Mixed carbon substrates: a necessary nuisance or a missed opportunity?

Although fermentation with single carbon sources is the preferred mode of operation in current industrial biotechnology, the use of multiple substrates has been continuously investigated throughout the years. Generally, microbial metabolism varies significantly when cells are presented with mixed carbon substrates compared to a single carbon-energy source, as different nutrients interact in complex ways within the metabolic network. By exploiting these distinct modes of interaction, researchers have identified unique opportunities to optimize metabolism using mixed carbon sources. Here we review situations where process yield and productivity are markedly improved through the judicious introduction of substrate mixtures. Our goal is to illustrate that with proper design of the choice of substrates and the way they are introduced to cultures, metabolic optimization with mixed substrates can be a unique strategy that complements genetic engineering techniques to enhance cell performance beyond what is accomplished in single substrate fermentations.

General information

Publication status: Published
MoE publication type: A2 Review article in a scientific journal
Organisations: Materials Science and Environmental Engineering, Massachusetts Institute of Technology, Department of Chemical Engineering
Contributors: Liu, N., Santala, S., Stephanopoulos, G.
Number of pages: 7
Pages: 15-21
Publication date: 1 Apr 2020
Peer-reviewed: Yes

Publication information

Journal: CURRENT OPINION IN BIOTECHNOLOGY
Volume: 62
ISSN (Print): 0958-1669
Original language: English
ASJC Scopus subject areas: Biotechnology, Bioengineering, Biomedical Engineering
Source: Scopus
Source ID: 85071874245

Research output: Contribution to journalReview ArticleScientificpeer-review

Linking volatile and non-volatile compounds to sensory profiles and consumer liking of wild edible Nordic mushrooms

Current information on the links between the chemistry and hedonic liking of edible mushrooms is scarce. In this study, 84 consumers evaluated the appearance, odor, taste, texture and overall liking of samples of Nordic edible wild mushroom species. Subsequently, multivariate models on the effects of non-volatile compounds, odor-contributing volatile compounds, sensory attributes and hedonic likings were created. The non-volatile compounds were measured with quantitative NMR. The five studied mushroom species were different in their sugar and acid contents. Three consumer clusters were found with species*cluster interactions. Correlations with sensory attributes and chemical components were found, and the multivariate models indicated predictor attributes for each consumer cluster. The results indicate that the sensory properties could be correlated to both volatile and non-volatile compounds, there are consumer clusters with differing likings as regards mushrooms, and these clusters are heterogenic groups with no simple factors such as age explaining their liking scores.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Turun yliopisto, Tokyo University of Agriculture
Contributors: Aisala, H., Manninen, H., Laaksonen, T., Linderborg, K. M., Myoda, T., Hopia, A., Sandell, M.
Publication date: 30 Jan 2020
Peer-reviewed: Yes

Publication information

Journal: Food Chemistry
Volume: 304
Article number: 125403
ISSN (Print): 0308-8146
Original language: English
ASJC Scopus subject areas: Analytical Chemistry, Food Science
Keywords: External preference mapping, Hedonic testing, Mushrooms, NMR, PLS
Source: Scopus
Source ID: 85071453617

Research output: Contribution to journalArticleScientificpeer-review

Power production and microbial community composition in thermophilic acetate-fed up-flow and flow-through microbial fuel cells

The microbial communities developed from a mixed-species culture in up-flow and flow-through configurations of thermophilic (55 °C) microbial fuel cells (MFCs), and their power production from acetate, were investigated. The up-flow MFC was operated for 202 days, obtaining an average power density of 0.13 W/m3, and Tepidiphilus was the dominant transcriptionally-active microorganisms. The planktonic community developed in the up-flow MFC was used to inoculate a flow-through MFC resulting in the proliferation of Ureibacillus, whose relative abundance increased from 1 to 61% after 45 days. Despite the differences between the up-flow and flow-through MFCs, including the anode electrode, hydrodynamic conditions, and the predominant microorganism, similar (p = 0.05) volumetric power (0.11–0.13 W/m3), coulombic efficiency (16–18%) and acetate consumption rates (55–69 mg/L/d) were obtained from both. This suggests that though MFC design can shape the active component of the thermophilic microbial community, the consortia are resilient and can maintain similar performance in different MFC configurations.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Bio- and Circular Economy, Natl. University of Ireland, Galway, Indian Institute of Technology Hyderabad
Contributors: Dessì, P., Chatterjee, P., Mills, S., Kokko, M., Lakaniemi, A., Collins, G., Lens, P. N.
Publication date: 1 Dec 2019
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 294
Article number: 122115
ISSN (Print): 0960-8524
Original language: English
ASJC Scopus subject areas: Bioengineering, Environmental Engineering, Renewable Energy, Sustainability and the Environment, Waste Management and Disposal
Keywords: Attached community, Bioelectrochemical system, Electrogenic microorganisms, MFC, Microbial electrochemical technology, Planktonic community
Source: Scopus
Source ID: 85072279751

Research output: Contribution to journalArticleScientificpeer-review

Programmable responsive hydrogels inspired by classical conditioning algorithm

Living systems have inspired research on non-biological dynamic materials and systems chemistry to mimic specific complex biological functions. Upon pursuing ever more complex life-inspired non-biological systems, mimicking even the most elementary aspects of learning is a grand challenge. We demonstrate a programmable hydrogel-based model system, whose behaviour is inspired by associative learning, i.e., conditioning, which is among the simplest forms of learning. Algorithmically, associative learning minimally requires responsivity to two different stimuli and a memory element. Herein, nanoparticles form the memory element, where a photoacid-driven pH-change leads to their chain-like assembly with a modified spectral behaviour. On associating selected light irradiation with heating, the gel starts to melt upon the irradiation, originally a neutral stimulus. A logic diagram describes such an evolution of the material response. Coupled chemical reactions drive the system out-of-equilibrium, allowing forgetting and memory recovery. The findings encourage to search non-biological materials towards associative and dynamic properties.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Chemistry & Advanced Materials, Aalto University
Contributors: Zhang, H., Zeng, H., Priimägi, A., Ikkala, O.
Publication date: 1 Dec 2019
Peer-reviewed: Yes

Publication information

Journal: Nature Communications
Volume: 10
Issue number: 1
Article number: 3267
ISSN (Print): 2041-1723
Original language: English
ASJC Scopus subject areas: Chemistry(all), Biochemistry, Genetics and Molecular Biology(all), Physics and Astronomy(all)
Electronic versions: 
Source: Scopus
Source ID: 85070331406

Research output: Contribution to journalArticleScientificpeer-review

Anaerobic treatment of LCFA-containing synthetic dairy wastewater at 20 °C: Process performance and microbial community dynamics

Facilitating anaerobic degradation of long-chain fatty acids (LCFA) is key for tapping the high methane production potential of the fats, oil and grease (FOG) content of dairy wastewaters. In this study, the feasibility of using high-rate granular sludge reactors for the treatment of mixed LCFA-containing synthetic dairy wastewater (SDW) was assessed at 20 °C. The effects of the LCFA concentration (33–45% of COD) and organic loading rates (2–3 gCOD/L·d) were determined using three parallel expanded granular sludge bed reactors. For the first time, long term anaerobic treatment of LCFA-containing feed at 20 °C was shown to be feasible and was linked to the microbial community dynamics in high-rate reactors. During a two-month operation, a soluble COD removal of 84–91% and COD to methane conversion of 44–51% was obtained. However, granular sludge flotation and washout occurred after two months in all reactors without volatile fatty acids (VFA) accumulation, emphasizing the need for sludge retention for long-term granular sludge reactor operation with LCFA-containing feed at low ambient temperatures. The temporal shifts in microbial community structure were studied in the high-rate treatment of SDW, and the process disturbances (elevated LCFA loading, LCFA accumulation, and batch operation) were found to decrease the microbial community diversity. The relative abundance of Methanosaeta increased with higher LCFA accumulation in the settled and flotation layer granules in the three reactors, therefore, acetoclastic methanogenesis was found to be crucial for the high-rate treatment of SDW at 20 °C. This study provides an initial understanding of the continuous anaerobic treatment of LCFA-containing industrial wastewaters at low ambient temperatures.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Tampere Water, Hydraulic and Environmental Engineering (IHE) Inst. for Water Education, Natl. University of Ireland, Galway
Contributors: Singh, S., Rinta-Kanto, J. M., Kettunen, R., Tolvanen, H., Lens, P., Collins, G., Kokko, M., Rintala, J.
Number of pages: 9
Pages: 960-968
Publication date: 15 Nov 2019
Peer-reviewed: Yes

Publication information

Journal: Science of the Total Environment
Volume: 691
ISSN (Print): 0048-9697
Original language: English
ASJC Scopus subject areas: Environmental Engineering, Environmental Chemistry, Waste Management and Disposal, Pollution
Keywords: Dairy wastewater, Expanded granular sludge bed (EGSB), Granule disintegration, Long chain fatty acids (LCFA), Methanogenesis pathway, Microbial community dynamics
Source: Scopus
Source ID: 85069487981

Research output: Contribution to journalArticleScientificpeer-review

Lewis Base-Catalyzed Modification of Ortho-Substituted Phenols

Lewis base catalysis in chemical transformations has received tremendous recognition in both academic and industrial applications over the years as it offers a convenient alternative to the use of expensive/toxic metal or large enzyme catalysts under mild reaction conditions. In light of this, efforts towards the development of synthetic strategies that employ Lewis base catalysts in mild and selective organic transformations are highly desirable.

In this thesis, we present an efficient Lewis base promoted hydrosilylation protocol with a novel cyclic 5-membered pinacol-derived chlorohydrosilane (PCS). This study provides information on the reactivity of this chlorohydrosilane as a hydride donor in the reduction of carbonyl and C=N moieties. Screening of various Lewis bases led to identification of DMPU as an effective catalyst for the hydrosilylation of salicylaldehydes. The role of the base as a catalyst in the reaction mechanism is further supported by computational studies. Hydroquinone serves as a starting material for the synthesis of formyl-hydroquinone, which was used to test the efficiency of our hydrosilylation protocol. The synthesis of hydroquinone from naturally available quinic acid was also studied. The hydrosilylation method was further developed for the preparation of novel tertiary alkylphenolmethyl amines employing pyridine as an effective Lewis base catalyst.

During the course of the study, the unprecedented preparation of 6, 12disubstituted methanodibenzo[b,f][1,5]dioxocins from pyrrolidine-catalyzed selfcondensation of 2’-hydroxyacetophenones was discovered and improved. This fascinating highly bridged polycyclic core is present in numerous biologically active natural products and pharmaceuticals.

The findings presented in this thesis exemplifies the high reactivity of PCS as a new reagent for Lewis base-catalyzed hydrosilylation. It is nevertheless envisioned that this silane finds usefulness in the hydrosilylation of other functional groups besides those employed in this work. In addition, the study provides mild and selective synthetic strategies to access diverse phenolic compounds of potential use by the pharmaceutical industry in the development of new bioactive molecules.

General information

Publication status: Published
MoE publication type: G5 Doctoral dissertation (article)
Organisations: Research group: Chemistry & Advanced Materials
Contributors: Assoah, B.
Number of pages: 76
Publication date: 15 Nov 2019

Publication information

Publisher: Tampere University
ISBN (Print): 978-952-03-1321-3
ISBN (Electronic): 978-952-03-1321-0
Original language: English

Publication series

Name: Tampere University Dissertations
Volume: 160
ISSN (Print): 2489-9860
ISSN (Electronic): 2490-0028

Research output: Book/ReportDoctoral thesisCollection of Articles

Miniature CoCr laser welds under cyclic shear: Fatigue evolution and crack growth

Miniature laser welds with the root depth in the range of 50–300 μm represent air-tight joints between the components in medical devices, such as those in implants, growth rods, stents and various prostheses. The current work focuses on the development of a fatigue test specimen and procedure to determine fatigue lives of shear-loaded laser welds. A cobalt-chromium (CoCr) alloy is used as a benchmark case. S–N graphs, damage process, and fracture surfaces are studied by applying x-ray analysis, atomic force microscopy, and scanning electron microscopy both before and after the crack onset. A non-linear material model is fitted for the CoCr alloy to run finite element simulations of the damage and deformation. As a result, two tensile-loaded specimen designs are established and the performance is compared to that of a traditional torque-loaded specimen. The new generation specimens show less variation in the determined fatigue lives due to well-defined crack onset point and, therefore, precise weld seam load during the experiments. The fatigue damage concentrates to the welded material and the entire weld experiences fatigue prior to the final, fracture-governed failure phase. For the studied weld seams of hardened CoCr, a regression fatigue limit of 10.8–11.8 MPa, where the stress refers to the arithmetic average shear stress computed along the region dominated by shear loading, is determined.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Orton Orthopaedic Hospital, Surface and Corrosion Science
Contributors: Kanerva, M., Besharat, Z., Pärnänen, T., Jokinen, J., Honkanen, M., Sarlin, E., Göthelid, M., Schlenzka, D.
Number of pages: 11
Pages: 93-103
Publication date: 1 Nov 2019
Peer-reviewed: Yes

Publication information

Journal: Journal of the Mechanical Behavior of Biomedical Materials
Volume: 99
ISSN (Print): 1751-6161
Original language: English
ASJC Scopus subject areas: Biomaterials, Biomedical Engineering, Mechanics of Materials
Keywords: CoCr, Crack growth, Fatigue, Implant, Laser weld
Electronic versions: 

Bibliographical note

EXT="Pärnänen, T."

Source: Scopus
Source ID: 85069732362

Research output: Contribution to journalArticleScientificpeer-review

Effects of elevated pressures on the activity of acidophilic bioleaching microorganisms

This study reports effects of elevated pressures on the oxidation of a soluble ferrous iron and low-grade sulphidic ore as little is known about biological iron and sulphur oxidation under these conditions. Pressure effects were studied in a pressurised batch-operated stirred tank reactor using acidophilic enrichment cultures. The oxidation of soluble Fe2+ by enrichment culture dominated by Leptospirillum ferriphilum, Sulfobacillus sp. and Ferrimicrobium acidiphilum increased with increasing pressure induced by technical air to up to +3 bar (0.63 bar PO2) and was inhibited at +7 bar (1.47 bar PO2). Elevated pressures induced by nitrogen (low oxygen partial pressure) were tolerated up to +40 bar. Another enrichment culture dominated by Acidithiobacillus ferrivorans, Sulfobacillus sp. and F. acidiphilum partially oxidised the ore at pressures up to +20 bar induced with air (4.2 bar PO2). This is the first study reporting activity of acidophiles under pressurised conditions in a stirred tank reactor.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering
Contributors: Hajdu-Rahkama, R., Ahoranta, S., Lakaniemi, A., Puhakka, J. A.
Publication date: 15 Oct 2019
Peer-reviewed: Yes

Publication information

Journal: Biochemical Engineering Journal
Volume: 150
Article number: 107286
ISSN (Print): 1369-703X
Original language: English
ASJC Scopus subject areas: Biotechnology, Bioengineering, Environmental Engineering, Biomedical Engineering
Keywords: Acidophiles, Biooxidation, Iron oxidation, Pressure tolerance, Pressurised stirred tank reactor
Source: Scopus
Source ID: 85070494949

Research output: Contribution to journalArticleScientificpeer-review

Utilizing mixed-mineralogy ferroan magnesite tailings as the source of magnesium oxide in magnesium potassium phosphate cement

A mixed-mineralogy talc mine tailing (MT) fraction consisting of 80% ferroan magnesite (MgCO3) was studied for utilization as the source of magnesium oxide (MgO) in magnesium potassium phosphate cement (MKPC). The effects of calcination temperature of this low-grade magnesite on the composition, BET surface area and phosphate reactivity of the resulting magnesia powder were studied. The 4-point flexural strength of resulting MKPC was measured for all calcined raw material fractions that produced a solid. Based on the strength measurement results, the optimal range for calcination resided between 700 °C and 1150 °C, which is drastically lower than commonly recommended for finer magnesia sources in MKPCs. Accelerated reactivity assessment showed that phosphate reactivity behavior could not be entirely predicted by BET surface area. The presence of impurity silicates and high iron content in all the constituent minerals was posed as the reason for densification and loss of reactivity at higher calcination temperatures.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Ceramic materials, Geological Survey of Finland, VTT Technical Research Centre of Finland
Contributors: Ismailov, A., Merilaita, N., Solismaa, S., Karhu, M., Levänen, E.
Publication date: 20 Jan 2020
Peer-reviewed: Yes
Early online date: 9 Oct 2019

Publication information

Journal: Construction and building materials
Volume: 231
Article number: 117098
ISSN (Print): 0950-0618
Original language: English
ASJC Scopus subject areas: Civil and Structural Engineering, Building and Construction, Materials Science(all)
Keywords: Bending strength, Chemically bonded ceramics, MgO, Mixed-mineralogy, pH, Phosphate cement, Surface area
Electronic versions: 

Bibliographical note

EXT="Karhu, Marjaana"

Source: Scopus
Source ID: 85072982997

Research output: Contribution to journalArticleScientificpeer-review

Controlled Orientations of Neighboring Tetracene Units by Mixed Self-Assembled Monolayers on Gold Nanoclusters for High-Yield and Long-Lived Triplet Excited States through Singlet Fission

Although tetracene (Tc) is well-known as a good candidate for singlet fission (SF), the number of high-yield and long-lived triplet excited states through SF is extremely limited because of the relative acceleration of the reverse triplet-triplet annihilation (TTA) considering the energy matching between a singlet and two triplet states. Systematic control of electronic interactions between two neighboring units using conventional covalent linkages and molecular assembly methods to optimize these kinetic processes is quite difficult because of the complicated synthesis and random orientations. In this study, we propose a novel supramolecular strategy utilizing mixed self-assembled monolayers (SAMs) with two different chain lengths. Specifically, mixed Tc-SAMs on gold nanoclusters, which are prepared using Tc-modified heterodisulfides with two different chain lengths, attain high-yield SF (ΦSF ≈ 90%) and individual triplet yields (ΦΤ ≈ 160%). The obtained ΦSF is the highest value among Tc derivatives in homogeneous solution to the best of our knowledge.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Chemistry & Advanced Materials, Keio University, Kobe University
Contributors: Saegusa, T., Sakai, H., Nagashima, H., Kobori, Y., Tkachenko, N. V., Hasobe, T.
Number of pages: 8
Pages: 14720-14727
Publication date: 18 Sep 2019
Peer-reviewed: Yes

Publication information

Journal: Journal of the American Chemical Society
Volume: 141
Issue number: 37
ISSN (Print): 0002-7863
Original language: English
ASJC Scopus subject areas: Catalysis, Chemistry(all), Biochemistry, Colloid and Surface Chemistry
Source: Scopus
Source ID: 85072270985

Research output: Contribution to journalArticleScientificpeer-review

Effects of anode materials on electricity production from xylose and treatability of TMP wastewater in an up-flow microbial fuel cell

The aim of this study was to determine an optimal anode material for electricity production and COD removal from xylose containing synthetic wastewater in an up-flow microbial fuel cell (MFC), and assess its suitability for treatment of thermomechanical pulping (TMP) wastewater with an enrichment culture at 37 °C. The anode materials tested included carbon-based electrodes (graphite plate, carbon cloth and zeolite coated carbon cloth), metal-based electrodes (tin coated copper) and a metal-carbon assembly (granular activated carbon in stainless steel cage). During continuous operation with xylose, COD removal was 77–86% of which 25–28% was recovered as electricity. The highest power density of 333 (±15) mW/m 2 was obtained with the carbon cloth electrode. However, based on an overall analysis including electrode performance, surface area and scalability, the granular activated carbon in stainless steel cage (GAC in SS cage) was chosen to be used as electrode for bioelectrochemical treatment of TMP wastewater. The TMP fed MFC was operated in continuous mode with 1.8 days hydraulic retention time, resulting in 47 (±13%) COD removal of which 1.5% was recovered as electricity with the average power production of 10–15 mW/m 2 . During operation with TMP wastewater, membrane fouling increased the polarization resistance causing a 50% decrease in power production within 30 days. This study shows that MFC pretreatment removes half of the TMP wastewater COD load, reducing the energy required for aerobic treatment.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Bio- and Circular Economy, Materials Science and Environmental Engineering, Natl. University of Ireland, Galway, Indian Institute of Technology Hyderabad, Microscopy Center, Kyung Hee University
Contributors: Haavisto, J., Dessì, P., Chatterjee, P., Honkanen, M., Noori, M. T., Kokko, M., Lakaniemi, A. M., Lens, P. N., Puhakka, J. A.
Number of pages: 10
Pages: 141-150
Publication date: 15 Sep 2019
Peer-reviewed: Yes

Publication information

Journal: Chemical Engineering Journal
Volume: 372
ISSN (Print): 1385-8947
Original language: English
ASJC Scopus subject areas: Chemistry(all), Environmental Chemistry, Chemical Engineering(all), Industrial and Manufacturing Engineering
Keywords: Electricity production, Electrode material, Granular activated carbon, Membrane fouling, Microbial electrochemical technology, Thermomechanical pulping wastewater
Source: Scopus
Source ID: 85064600846

Research output: Contribution to journalArticleScientificpeer-review

Effects of nanofibrillated cellulose hydrogels on adipose tissue extract and hepatocellular carcinoma cell spheroids in freeze-drying

The aim of this study was to evaluate the effects of two nanofibrillated cellulose (NFC) hydrogels on two human derivatives during freeze-drying. Native NFC hydrogel is a suitable platform to culture 3D cell spheroids and a hydrogel processed further, called anionic NFC (ANFC) hydrogel, is an excellent platform for controlled release of proteins. Moreover, it has been shown to be compatible with freeze-drying when correct lyoprotectants are implemented. Freeze-drying is a method, where substance is first frozen, and then vacuum dried trough sublimation of water in order to achieve dry matter without the loss of the original three-dimensional structures. The first chosen human derivative was adipose tissue extract (ATE) which is a cell-free growth factor-rich preparation capable of promoting growth of regenerative cells. The release of growth factors from the freeze-dried mixture of ATE and ANFC was compared to that of non-freeze-dried control mixtures. The release profiles remained at the same level after freeze-drying. The second derivative was hepatocellular carcinoma (HepG2) cell spheroids which were evaluated before and after freeze-drying. The 3D structure of the HepG2 cell spheroids was preserved and the spheroids retained 18% of their metabolic activity after rehydration. However, the freeze-dried and rehydrated HepG2 cell spheroids did not proliferate and the cell membrane was damaged by fusion and formation of crystals.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Chemistry & Advanced Materials, University of Helsinki, Tampere University, Universita degli Studi di Padova, Italy
Contributors: Auvinen, V., Merivaara, A., Kiiskinen, J., Paukkonen, H., Laurén, P., Hakkarainen, T., Koivuniemi, R., Sarkanen, R., Ylikomi, T., Laaksonen, T., Yliperttula, M.
Publication date: 15 Sep 2019
Peer-reviewed: Yes

Publication information

Journal: Cryobiology
ISSN (Print): 0011-2240
Original language: English
ASJC Scopus subject areas: Biochemistry, Genetics and Molecular Biology(all), Agricultural and Biological Sciences(all)
Keywords: 3D cell culture, Adipose tissue extract, Cell spheroids, Freeze-drying, Nanofibrillated cellulose

Bibliographical note

dupl=50229030

Source: Scopus
Source ID: 85072559849

Research output: Contribution to journalArticleScientificpeer-review

Critical Sensitizer Quality Attributes for Efficient Triplet−Triplet Annihilation Upconversion with Low Power Density Thresholds

Triplet-triplet annihilation upconversion (TTAUC) is a power density-dependent process where photons of low energy are transformed into high energy ones. The most important attributes of efficient TTAUC are quantum yield φTTAUC, power density threshold Ith (photon flux at which 50% of φTTAUC is achieved), and the upconversion shift of emitted photons (anti-Stokes shift). To date, approaches to balance these parameters have remained unclear. Herein, the cumulative effect of sensitizer triplet lifetime (τ0 S), sensitizer-annihilator triplet energy gap (ΔET), and the total concentration of the sensitizer on the power density threshold at high TTAUC quantum yields is evaluated experimentally using Pt, Pd, and Zn tetraphenylporphyrin derivatives and a tetra-tert-butylperylene annihilator, and by kinetic rate modeling. The results suggest that a large energy gap (ΔET ≥ 4 kBT) and long sensitizer triplet lifetime make the triplet-triplet energy transfer (TTET) extremely efficient and allow the utilization of high sensitizer concentrations for low Ith. However, for large upconversion shifts, the triplet energy gap should be as small as possible. Smaller energy gap values result in slower forward TTET and faster reverse TTET, which together with high total sensitizer concentration can lead to a quenching of annihilator's triplet state and therefore elevate the Ith. In this regard, low concentration of a sensitizer is beneficial, making sensitizers with high molar extinction coefficients preferential. Sensitizers with a long living triplet state and a high molar extinction coefficient can work efficiently and have low Ith at 0 kBT or even negative ΔET. Kinetic rate modeling further helps to optimize the parameters for best possible TTAUC performance. Thus, the findings of the study pave the way for the design of TTAUC systems with superior performance, such as high φTTAUC at low excitation power densities with large anti-Stokes shift, for, for example, solar-driven photovoltaics, photocatalysis, bioimaging, and safe light-triggered drug-delivery systems.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Chemistry & Advanced Materials
Contributors: Durandin, N., Isokuortti, J., Efimov, A., Vuorimaa-Laukkanen, E., Tkachenko, N. V., Laaksonen, T.
Pages: 22865−22872
Publication date: 26 Aug 2019
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry C
Volume: 123
Issue number: 37
ISSN (Print): 1932-7447
Original language: English

Research output: Contribution to journalArticleScientificpeer-review

Nano-structured TiO2 grown by low-temperature reactive sputtering for planar perovskite solar cells

Low-temperature nanostructured electron-transporting layers (ETLs) for perovskite solar cells are grown by reactive sputtering at 160 °C with thickness in the range 22–76 nm and further stabilization in air at 180 °C to improve the lattice structure and to consequently reduce charge recombination during solar cell operation. In addition, the post-deposition treatment aims at leveling differences among samples to ensure material reproducibility. Nanostructured TiO2 has a further added value in promoting the structural coupling with the perovskite layer and establishing conformal interfaces in favor of the charge extraction from the active material. Nanostructuring of the ETLs also allows the shaping of the band gap width and position with a beneficial impact on the electrical parameters, as tested in standard architecture containing methylammonium lead iodide perovskites. A balance among parameters is achieved using a 40-nm-thick TiO2 ETL with a maximum efficiency of ∼15% reached without surface treatments or additional layers. The proposed growth methodology would be compatible with the use of flexible substrates after appropriated ETL structural adaptation. It can be likewise applied in perovskite/silicon-heterojunction tandem solar cells to fulfill the industrial demand for clean, solvent-free, reproducible, reliable, and high-throughput processes.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Chemistry & Advanced Materials
Contributors: Alberti, A., Smecca, E., Sanzaro, S., Bongiorno, C., Giannazzo, F., Mannino, G., La Magna, A., Liu, M., Vivo, P., Listorti, A., Calabro', E., Matteocci, F., Di Carlo, A.
Number of pages: 12
Pages: 6218-6229
Publication date: 16 Aug 2019
Peer-reviewed: Yes

Publication information

Journal: ACS Applied Energy Materials
Volume: 2
Issue number: 9
ISSN (Print): 2574-0962
Original language: English

Research output: Contribution to journalArticleScientificpeer-review

Chlorine induced high-temperature corrosion mechanisms in HVOF and HVAF sprayed Cr3C2-based hardmetal coatings

A novel method that combines thermal analysis and traditional furnace corrosion tests was used to study the corrosion behaviour of thermally sprayed Cr3C2-based hardmetal coatings at 450 °C and 550 °C under a KCl deposit. This method enabled the identification of the onset temperature of chlorine-induced oxidation to be within 450–500 °C. Two corrosion mechanisms were suggested for these temperatures. At 450 °C, the corrosion rate was slow and mainly controlled by the formation of K2CrO4. Exposure at 550 °C caused the formation of fine interconnected secondary-carbide precipitates in the metal matrix. Their fast corrosion was identified as the major cause of degradation.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Surface Engineering, Valmet Automation Oy
Contributors: Fantozzi, D., Matikainen, V., Uusitalo, M., Koivuluoto, H., Vuoristo, P.
Publication date: 14 Aug 2019
Peer-reviewed: Yes

Publication information

Journal: Corrosion Science
Article number: 108166
ISSN (Print): 0010-938X
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all), Materials Science(all)
Keywords: A. Metal matrix composites, A. Superalloys, B. SEM, B. TGA, B. XRD, C. Chlorination, C. High temperature corrosion, C. Thermodynamic diagrams

Bibliographical note

EXT="Uusitalo, Mikko"

Source: Scopus
Source ID: 85072275416

Research output: Contribution to journalArticleScientificpeer-review

Alkane and wax ester production from lignin-related aromatic compounds

Lignin has potential as a sustainable feedstock for microbial production of industrially relevant molecules. However, the required lignin depolymerization yields a heterogenic mixture of aromatic monomers that are challenging substrates for the microorganisms commonly used in the industry. Here, we investigated the properties of lignin-related aromatic compounds (LRAs), namely coumarate, ferulate, and caffeate, in the synthesis of biomass and products in an LRA-utilizing bacterial host Acinetobacter baylyi ADP1. The biosynthesis products, wax esters, and alkanes are relevant compounds for the chemical and fuel industries. Here, wax esters were produced by a native pathway of ADP1, whereas alkanes were produced by a synthetic pathway introduced to the host. Using individual LRAs as substrates, the growth and product formation were monitored with internal biosensors and off-line analytics. Of the tested LRAs, coumarate was the most propitious in terms of product synthesis. Wax esters were produced from coumarate with yield and titer of 37 mg/gcoumarate and 202 mg/L, whereas alkanes were produced with a yield of 62.3 µg /gcoumarate and titer of 152 µg/L. This study demonstrates the microbial preference for certain LRAs and highlights the potential of A. baylyi ADP1 as a host for LRA upgrading to value-added products.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Bio- and Circular Economy
Contributors: Salmela, M., Lehtinen, T., Efimova, E., Santala, S., Santala, V.
Number of pages: 12
Pages: 1934-1945
Publication date: 1 Aug 2019
Peer-reviewed: Yes

Publication information

Journal: Biotechnology and Bioengineering
Volume: 116
Issue number: 8
ISSN (Print): 0006-3592
Original language: English
ASJC Scopus subject areas: Biotechnology, Bioengineering, Applied Microbiology and Biotechnology
Keywords: Acinetobacter baylyi ADP1, alkane, lignin, wax ester
Source: Scopus
Source ID: 85070728183

Research output: Contribution to journalArticleScientificpeer-review

Photochemistry of dithiophosphinate Ni(S2P(i-Bu)2)2 complex in CCl4. Transient species and TD-DFT calculations

Femtosecond spectroscopy and nanosecond laser flash photolysis were used to study the photophysical and photochemical transformations of the bis-diisobutyl-dithiophosphinate Ni(II)complex (Ni(S2P(i-Bu)2)2 = Ni(dtpi)2, where dtpiS2P(i-Bu)2)in CCl4 solutions. The radiation of second harmonic (405 nm)of Ti:Sapphire laser transfers the Ni(dtpi)2 complex to an excited 1LMCT state. Its decay in CCl4 is described by three exponents with time constants 0.58, 2.0 and ˜150 ps. The first process apparently involves the fast transitions from 1LMCT state to 3LMCT due to the intersystem crossing (ISC)and then to lower-lying “hot” 3LF (Ligand Field)state. The second time constant, most likely, corresponds to the vibrational cooling of this “hot” 3LF state. And the third slow process is the transition from 3LF state to ground state (1GS). The quantum yield of photochemical transformation under the 405 irradiation is close to zero, so the study of photochemistry was performed with a nanosecond flash photolysis at 308 nm. In this case an electron transfer from the excited Ni(dtpi)2 complex to a solvent molecule leads to the appearance of primary intermediate, the [ClNi(dtpi)(dtpi[rad])]complex, in which a dtpi[rad] radical is coordinated with a nickel ion via one sulfur atom. In the fast reaction with Ni(dtpi)2, this complex forms a long-lived dimer ClNi(dtpi)(dtpi[rad])[Ni(dtpi)2]. This intermediate for a few hundred microseconds decays in the reaction of recombination with the formation of (dtpi)2 disulphide and unstable ClNi(dtpi)complex. The insoluble NiCl2 salt falled in CCl4 as the sediment due to the reaction of two ClNi(dtpi)complexes. The quantum chemical calculations allowed to determine the geometry of the intermediate complexes arising in the photochemistry of Ni(S2P(i-Bu)2)2 complex.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Voevodsky Institute of Chemical Kinetics and Combustion SB RAS, Novosibirsk State University, Boreskov Institute of Catalysis SB RAS, Nikolaev Institute of Inorganic Chemistry SB RAS
Contributors: Solovyev, A. I., Mikheylis, A. V., Plyusnin, V. F., Shubin, A. A., Grivin, V. P., Larionov, S. V., Tkachenko, N. V., Lemmetyinen, H.
Publication date: 1 Aug 2019
Peer-reviewed: Yes

Publication information

Journal: Journal of Photochemistry and Photobiology A: Chemistry
Volume: 381
Article number: 111857
ISSN (Print): 1010-6030
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all), Physics and Astronomy(all)
Keywords: Bis-diisobutyl-dithiophosphinate Ni(II)complex, Intermediate particles, Kinetics, Laser flash photolysis, Photolysis mechanism, Quantum-chemical calculation
Source: Scopus
Source ID: 85067953554

Research output: Contribution to journalArticleScientificpeer-review

Pyrolytic behavior of lignocellulosic-based polysaccharides

The thermochemical behavior of cellulose, glucomannan, and xylan was investigated by pyrolysis–gas chromatography-mass spectrometry (Py-GC/MS). In each case, major GC-amenable condensable products were classified into several compound groups, and the formation of these monomer-related fragments from the model substance samples was determined at 500, 600, and 700 °C with a residence time of 5 s and 20 s. The results revealed that despite some general formation trends, no compound group was selectively formed at certain temperatures. Of the 11 product groups, the primary ones, including lactone, furan, and cyclopentenone derivatives, accounted for 72–85% (from cellulose), 86–90% (from glucomannan), and 76–81% (from xylan) of the total amount of pyrolysis products determined. At 500 °C, about half of the major product groups accounted for lactones, such as 3-hydroxy-2-penteno-1,5-lactone and 5H-furan-2-one. It was also confirmed by thermogravimetric analyses that within the temperature range studied, cellulose was thermally more stable than the heterogeneous hemicelluloses. These kinds of data are of importance, for example, with respect to efforts to develop new biorefinery possibilities for renewable resources.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, University of Jyvaskyla
Contributors: Ghalibaf, M., Doddapaneni, T. R. K. C., Alén, R.
Pages: 121-131
Publication date: Jul 2019
Peer-reviewed: Yes
Early online date: 2018

Publication information

Journal: Journal of Thermal Analysis and Calorimetry
Volume: 137
Issue number: 1
ISSN (Print): 1388-6150
Original language: English
ASJC Scopus subject areas: Condensed Matter Physics, Physical and Theoretical Chemistry
Keywords: Cellulose, Condensable products, Glucomannan, Pyrolysis–gas chromatography, Thermogravimetry, Xylan
Source: Scopus
Source ID: 85057074557

Research output: Contribution to journalArticleScientificpeer-review

Photocontrol of Supramolecular Azo-Containing Block Copolymer Thin Films during Dip-Coating: Toward Nanoscale Patterned Coatings

Dip-coating allows nanostructured block copolymer (BCP) thin film fabrication in a fast and facile one-step process. It can also be coupled with external controls, such as illumination. Herein, we expose several design principles that enable photocontrol of the nanostructured surface pattern and thickness of supramolecular BCP thin films. This is done using a polystyrene-poly(4-vinylpyridine) (PS-P4VP) BCP and two hydroxy-functionalized small-molecule (SM) azo derivatives that have different photochemical characteristics and that hydrogen bond to the P4VP block. We show how the film preparation concept provides tunability through the chemical structure of the photoactive SM, the relative amount of SM in the dip-coating solution, and the choice of solvent. It was found that the film thickness and SM uptake in the films are increased by illumination when THF is used but are unchanged when toluene is used as solvent, which is attributed to an optical heating effect observable with volatile solvents. The photocontrol of surface patterns is a result of photoinduced changes in the effective volume fraction of the P4VP+SM phase, which is increased by a greater volume of cis isomers, by higher SM uptake (using THF), and by more trans-cis-trans cycling for systems with shorter cis lifetime. The extent of photoinduced change can also be increased by higher molecular mobility due to more flexible SMs, lower BCP molecular weight, and nonmicellar or softer micellar solutions.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Chemistry & Advanced Materials, Département de Chimie, Succ. Centre-Ville
Contributors: Vapaavuori, J., Grosrenaud, J., Siiskonen, A., Priimägi, A., Pellerin, C., Bazuin, C. G.
Number of pages: 12
Pages: 3526-3537
Publication date: 28 Jun 2019
Peer-reviewed: Yes

Publication information

Journal: ACS Applied Nano Materials
Volume: 2
Issue number: 6
ISSN (Print): 2574-0970
Original language: English
ASJC Scopus subject areas: Materials Science(all)
Keywords: azo-containing, block copolymer thin films, dip-coating, nanoscale patterns, photocontrol, supramolecular

Bibliographical note

EXT="Vapaavuori, Jaana"

Source: Scopus
Source ID: 85068593381

Research output: Contribution to journalArticleScientificpeer-review

Photoreversible Soft Azo Dye Materials: Toward Optical Control of Bio‐Interfaces

Photoreversible optically switchable azo dye molecules in polymer‐based materials can be harnessed to control a wide range of physical, chemical, and mechanical material properties in response to light, that can be exploited for optical control over the bio‐interface. As a stimulus for reversibly influencing adjacent biological cells or tissue, light is an ideal triggering mechanism, since it can be highly localized (in time and space) for precise and dynamic control over a biosystem, and low‐power visible light is also an inherently gentle, benign, and nondamaging stimulus in a biological environment. Azobenzene‐based dyes in particular are emerging as especially attractive candidates among photoreversible molecules, and soft azobenzene‐containing materials are promising due to their ease of incorporation, and efficient and robust photochemistry and photophysics. This review provides a current survey of the use of photoreversible azo soft materials in cell biology and tissue engineering bio‐interface applications, to afford light control over molecular motion (orientation, flow), by inscribing surface morphological patterns or macroscopically photoactuating surfaces and structures, via three key photophysical and bioactive effects enabled by the azo groups' light‐induced photo‐orientation, topological optical patterning, and photomechanical actuation.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, McGill University, Tokyo Institute of Technology
Contributors: Chang, V. Y., Fedele, C., Priimägi, A., Shishido, A., Barrett, C. J.
Pages: 1900091
Publication date: 29 May 2019
Peer-reviewed: Yes

Publication information

Journal: Advanced Optical Materials
ISSN (Print): 2195-1071
Original language: English

Research output: Contribution to journalArticleScientificpeer-review

Lasing in Ni Nanodisk Arrays

We report on lasing at visible wavelengths in arrays of ferromagnetic Ni nanodisks overlaid with an organic gain medium. We demonstrate that by placing an organic gain material within the mode volume of the plasmonic nanoparticles both the radiative and, in particular, the high ohmic losses of Ni nanodisk resonances can be compensated. Under increasing pump fluence, the systems exhibit a transition from lattice-modified spontaneous emission to lasing, the latter being characterized by highly directional and sub-nanometer line width emission. By breaking the symmetry of the array, we observe tunable multimode lasing at two wavelengths corresponding to the particle periodicity along the two principal directions of the lattice. Our results are relevant for loss-compensated magnetoplasmonic devices and topological photonics.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Aalto University, University of Eastern Finland, Campus de la UAB
Contributors: Pourjamal, S., Hakala, T. K., Nečada, M., Freire-Fernández, F., Kataja, M., Rekola, H., Martikainen, J. P., Törmä, P., Van Dijken, S.
Number of pages: 7
Pages: 5686-5692
Publication date: 28 May 2019
Peer-reviewed: Yes

Publication information

Journal: ACS Nano
Volume: 13
Issue number: 5
ISSN (Print): 1936-0851
Original language: English
ASJC Scopus subject areas: Materials Science(all), Engineering(all), Physics and Astronomy(all)
Keywords: loss-compensated magnetoplasmonics, nanolasing, Ni nanodisk array, plasmonics, surface lattice resonance
Electronic versions: 
Source: Scopus
Source ID: 85064967811

Research output: Contribution to journalArticleScientificpeer-review

Photoinduced Charge Transfer Processes at Organic-Semiconductor Interfaces

The growing energy demand of the mankind has lead to the extensive use of fossil fuels. The burning of oil, coal and natural gas has increased the global temperature and atmospheric carbon dioxide percentage to a dangerously high level. Therefore, carbon-neutral energy sources such as solar cells are needed.

In order to design more effective solar cells, a deep understanding of the primary photochemical processes in the cells is needed. Ultrafast time-resolved spectroscopy, especially transient absorption methods, are a very useful tool for investigating the reaction kinetics in order to optimize the solar cell performance.

In this thesis, kinetics of the photoinduced processes at the interface of an organic monomolecular layer and a semiconductor are studied. Such structures may be used as the active material e.g. in dye-sensitized solar cells. Two different types of organic–semiconductor hybrids were prepared: fullerenes (C60) immobilized on colloidal semiconductor quantum dots (QDs), and zinc phthalocyanine (ZnPc) derivatives on nanostructured titanium dioxide (TiO2) and zinc oxide (ZnO) surfaces. The driving force of photocurrent generation in these systems is a photonic excitation leading to an electron transfer reaction across the organic–semiconductor interface. The observed electron transfer rates vary from a few picoseconds in ZnPc monolayers on TiO2 to ca. 100 ps in QD–fullerene systems.

Phthalocyanine derivatives are very attractive sensitizing dyes for solar cell applications because of their excellent stability and strong absorption in the red part of the spectrum. A drawback with these compounds is their tendency towards aggregation. It reduces the solar cell efficiencies due to intra-aggregate losses. There are two common methods for aggregation-reduction: the use of molecular co-adsorbates and substitution of the phthalocyanine core with bulky side groups. Both mechanisms were observed to lower the degree of aggregation in the ZnPc samples. The substitution method proved to be more efficient in terms of the lifetime of the charge-separated state.

To more realistically mimic a solar cell, a hole-transporting material (HTM) was used. Its effect on the primary photoinduced reactions in the phthalocyanine–semiconductor samples was studied. With the chosen HTM, spiro-MeOTAD, the charge separation was observed to occur first at the phthalocyanine–HTM interface, followed by electron injection into the semiconductor material.

Complete solar cell samples were prepared in order to link the ultrafast spectroscopy results to actual solar cell performance. A correlation between the degree of aggregation and the produced photocurrent was confirmed. The less aggregated samples produce a higher photocurrent per number of absorbed photons. This study indentifies bottlenecks in modern hybrid organic–semiconductor solar cell design and suggests solutions for improving the solar cell performance.

General information

Publication status: Published
MoE publication type: G5 Doctoral dissertation (article)
Organisations: Materials Science and Environmental Engineering
Contributors: Virkki, K.
Number of pages: 55
Publication date: 24 May 2019

Publication information

Publisher: Tampere University
ISBN (Print): 978-952-03-1101-8
ISBN (Electronic): 978-952-03-1102-5
Original language: English

Publication series

Name: Tampere University Dissertations
Volume: 67
ISSN (Print): 2489-9860
ISSN (Electronic): 2490-0028

Research output: Book/ReportDoctoral thesisCollection of Articles

Bioinspired Light Robots from Liquid Crystal Networks

Bioinspired material research aims at learning from the sophisticated design principles of nature, in order to develop novel artificial materials with advanced functionalities. Some of the sophisticated capabilities of biological materials, such as their ability to self-heal or adapt to environmental changes, are challenging to realize in artificial systems. Nevertheless, many efforts have been recently devoted to develop artificial materials with adaptive functions, especially materials which can generate movement in response to external stimuli. One such effort is the field of soft robots, which aims towards fabrication of autonomous adaptive systems with flexibility, beyond the current capability of conventional robotics. However, in most cases, soft robots still need to be connected to hard electronics for powering and rely on complicated algorithms to control their deformation modes. Soft robots that can be powered remotely and are capable of self-regulating function, are of great interest across the scientific community.

In order to realize such responsive and adaptive systems, researches across the globe are making constant efforts to develop new, ever-more sophisticated stimuliresponsive materials. Among the different stimuli-responsive materials, liquid crystal networks (LCNs) are the most suited ones to design smart actuating systems as they can be controlled and powered remotely with light and thereby obviate the need for external control circuitry. They enable pre-programable shape changes, hence equipping a single material with multiple actuation modes. In addition to light, they can also be actuated by variety of stimuli such as heat, humidity, pH, electric and magnetic fields etc., or a combination of these. Based on these advantages of LCNs, we seek inspiration from natural actuator systems present in plants and animals to devise different light controllable soft robotic systems.

In this thesis, inspired from biological systems such as octopus arm movements, iris movements in eyes, object detection and capturing ability of Venus flytraps and opening and closing of certain nocturnal flowers, we demonstrate several light robots that can be programmed to show pre-determined shape changes. By employing a proper device design, these light robots can even show the characteristics of selfregulation and object recognition, which brings new advances to the field of LCNbased light robots. For instance, octopod light robot can show bidirectional bending owing to alignment programming using a commercial laser projector; artificial iris is a fully light controllable device that can self-regulate its aperture size based on intensity of incident light; the optical flytrap can not only autonomously close on an object coming into its ‘‘mouth’’ but it can also distinguish between different kinds of objects based on optical feedback, and finally, integration of light and humidity responsiveness in a single LCN actuator enables a nocturnal flower-mimicking actuator, which provides an opportunity to understand the delicate interplay between different simultaneously occurring stimuli in a monolithic actuator.

We believe that besides providing a deeper understanding on the photoactuation in liquid crystal networks, at fundamental level, our work opens new avenues by providing several pathways towards next-generation intelligent soft microrobots.

General information

Publication status: Published
MoE publication type: G5 Doctoral dissertation (article)
Organisations: Materials Science and Environmental Engineering, Research group: Chemistry & Advanced Materials
Contributors: Wani, O.
Number of pages: 70
Publication date: 17 May 2019

Publication information

Publisher: Tampere University
ISBN (Print): 978-952-03-1095-0
ISBN (Electronic): 978-952-03-1096-7
Original language: English

Publication series

Name: Tampere University Dissertations
Volume: 64
ISSN (Print): 2489-9860
ISSN (Electronic): 2490-0028

Research output: Book/ReportDoctoral thesisCollection of Articles

Dopant-free hole-transporting materials via thionation approach towards stable and efficient perovskite solar cells

General information

Publication status: Published
MoE publication type: Not Eligible
Organisations: Materials Science and Environmental Engineering
Contributors: Liu, M., Vivo, P.
Publication date: 12 May 2019
Peer-reviewed: Unknown
Event: Paper presented at HOPV 2019, Rome, Italy.

Research output: Other conference contributionPaper, poster or abstractScientific

Long-term performance evaluation of an anoxic sulfur oxidizing moving bed biofilm reactor under nitrate limited conditions

An anoxic sulfur-oxidizing moving bed biofilm reactor (MBBR) treating sulfur and nitrate-contaminated synthetic wastewater was monitored for 306 days under feed nitrogen-to-sulfur (N/S) molar ratios of 0.5, 0.3 and 0.1. Thiosulfate (S2O32−) removal efficiencies (RE) exceeding 98% were observed at a N/S ratio of 0.5 and a S2O32− loading rate of 0.9 g S2O32−–S L−1 d−1, whereas a RE of 82.3 (±2.6)% and 37.7 (±3.4)% were observed at N/S ratios of 0.3 and 0.1, respectively. Complete nitrate (NO3−) removal was obtained at all tested N/S ratios. A comparison of the kinetic parameters of the MBBR biomass under the same stoichiometric conditions (N/S ratio of 0.5) revealed a 1.3-fold increase of the maximum specific rate of S2O32− oxidation (rmax) and a 30-fold increase of the affinity constant for S2O32− (Ks) compared to those observed after long-term NO3− limitation (N/S ratio of 0.1). The MBBR showed optimal resilience to NO3− limitation as the S2O32− RE recovered from 37.3% to 94.1% within two days after increasing the N/S ratio from 0.1 to 0.5. Based on PCR-DGGE analysis, sulfur-oxidizing nitrate-reducing bacteria, i.e. Thiobacillus sp. and Sulfuritalea sp., dominated in the MBBR biofilm during the entire study.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Bio- and Circular Economy, Materials Science and Environmental Engineering, Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, ENEA/CREATE/Università Degli Studi Napoli Federico II, Wageningen University and the UNESCO-IHE Institute for Water Education, Delft, The Netherlands, 18.10.2013, Hydraulic and Environmental Engineering (IHE) Inst. for Water Education
Contributors: Khanongnuch, R., Di Capua, F., Lakaniemi, A., Rene, E. R., Lens, P.
Pages: 1072-1081
Publication date: 29 Apr 2019
Peer-reviewed: Yes

Publication information

Journal: Environmental Science: Water Research & Technology
Volume: 5
Issue number: 6
ISSN (Print): 2053-1400
Original language: English

Research output: Contribution to journalArticleScientificpeer-review

Halide Perovskite Nanocrystals for Next‐Generation Optoelectronics

Colloidal perovskite nanocrystals (PNCs) combine the outstanding optoelectronic properties of bulk perovskites with strong quantum confinement effects at the nanoscale. Their facile and low-cost synthesis, together with superior photoluminescence quantum yields and exceptional optical versatility, make PNCs promising candidates for next-generation optoelectronics. However, this field is still in its early infancy and not yet ready for commercialization due to several open challenges to be addressed, such as toxicity and stability. Here, the key synthesis strategies and the tunable optical properties of PNCs are discussed. The photophysical underpinnings of PNCs, in correlation with recent developments of PNC-based optoelectronic devices, are especially highlighted. The final goal is to outline a theoretical scaffold for the design of high-performance devices that can at the same time address the commercialization challenges of PNC-based technology.

General information

Publication status: Published
MoE publication type: A2 Review article in a scientific journal
Organisations: Materials Science and Environmental Engineering
Contributors: Liu, M., Zhang, H., Gedamu, D., Fourmont, P., Rekola, H., Hiltunen, A., Cloutier, S. G., Nechache, R., Priimägi, A., Vivo, P.
Publication date: 23 Apr 2019
Peer-reviewed: Yes

Publication information

Journal: Small
Article number: 1900801
ISSN (Print): 1613-6810
Original language: English

Research output: Contribution to journalReview ArticleScientificpeer-review

H2S removal and microbial community composition in an anoxic biotrickling filter under autotrophic and mixotrophic conditions

Removal of H2S from gas streams using NO3--containing synthetic wastewater was investigated in an anoxic biotrickling filter (BTF) at feed N/S ratios of 1.2-1.7 mol mol-1 with an initial nominal empty bed residence time of 3.5 min and a hydraulic retention time of 115 min. During 108 days of operation under autotrophic conditions, the BTF showed a maximum elimination capacity (EC) of 19.2 g S m-3 h-1 and H2S removal efficiency (RE) above 99%. Excess biofilm growth reduced the HRT from 115 to 19 min and decreased the desulfurization efficiency of the BTF. When the BTF was operated under mixotrophic conditions by adding organic carbon (43.2 g acetate m-3 h-1) to the synthetic wastewater, the H2S EC decreased from 16.4 to 13.1 g S m-3 h-1, while the NO3- EC increased from 9.9 to 11.1 g NO3--N m-3 h-1, respectively. Thiobacillus sp. (98-100% similarity) was the only sulfur-oxidizing nitrate-reducing bacterium detected in the BTF biofilm, while the increased abundance of heterotrophic denitrifiers, i.e. Brevundimonas sp. and Rhodocyclales, increased the consumed N/S ratio during BTF operation. Residence time distribution tests showed that biomass accumulation during BTF operation reduced gas and liquid retention times by 17.1% and 83.5%, respectively.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, UNESCO–IHE, Department of Civil, Architectural and Environmental Engineering (DICEA), University of Naples Federico II
Contributors: Khanongnuch, R., Di Capua, F., Lakaniemi, A., Rene, E. R., Lens, P.
Pages: 397-406
Publication date: 5 Apr 2019
Peer-reviewed: Yes
Early online date: 18 Dec 2018

Publication information

Journal: Journal of Hazardous Materials
Volume: 367
ISSN (Print): 0304-3894
Original language: English
Keywords: H2S removal, autotrophic denitrification, nitrate-containing wastewater, substrate competition, PCR-DGGE

Research output: Contribution to journalArticleScientificpeer-review

GIS-data related route optimization, hierarchical clustering, location optimization, and kernel density methods are useful for promoting distributed bioenergy plant planning in rural areas

Currently, geographic information system (GIS) models are popular for studying location-allocation-related questions concerning bioenergy plants. The aim of this study was to develop a model to investigate optimal locations for two different types of bioenergy plants, for farm and centralized biogas plants, and for wood terminals in rural areas based on minimizing transportation distances. The optimal locations of biogas plants were determined using location optimization tools in R software, and the optimal locations of wood terminals were determined using kernel density tools in ArcGIS. The present case study showed that the utilized GIS tools are useful for bioenergy-related decision-making to identify potential bioenergy areas and to optimize biomass transportation, and help to plan power plant sizing when candidate bioenergy plant locations have not been defined in advance. In the study area, it was possible to find logistically viable locations for 13 farm biogas plants (>100 kW) and for 8 centralized biogas plants (>300 kW) using a 10-km threshold for feedstock supply. In the case of wood terminals, the results identified the most intensive wood reserves near the highest road classes, and two potential locations were determined.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Bio- and Circular Economy, University of Jyvaskyla, Seinäjoki University of Applied Sciences
Contributors: Laasasenaho, K., Lensu, A., Lauhanen, R., Rintala, J.
Number of pages: 11
Pages: 47-57
Publication date: 1 Apr 2019
Peer-reviewed: Yes

Publication information

Journal: Sustainable Energy Technologies and Assessments
Volume: 32
ISSN (Print): 2213-1388
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology
Keywords: Biogas, Circular economy, Location-allocation, Network analysis, Wood terminal
URLs: 
Source: Scopus
Source ID: 85061098980

Research output: Contribution to journalArticleScientificpeer-review

Impacts of short-term temperature fluctuations on biohydrogen production and resilience of thermophilic microbial communities

Anaerobic microflora enriched for dark fermentative H2 production from a mixture of glucose and xylose was used in batch cultivations to determine the effects of sudden short-term temperature fluctuations on H2 yield and microbial community composition. Batch cultures initially cultivated at 55 °C (control) were subjected to downward (from 55 °C to 35 °C or 45 °C) or upward (from 55 °C to 65 °C or 75 °C) temperature shifts for 48 h after which, each culture was transferred to a fresh medium and cultivated again at 55 °C for two consecutive batch cycles. The average H2 yield obtained during the first cultivation at 55 °C was 2.1 ± 0.14 mol H2 mol-1 hexose equivalent. During the temperature shifts, the obtained H2 yields were 1.8 ± 0.15, 1.6 ± 0.27 and 1.9 ± 0.00 mol H2 mol-1 hexose equivalent at 35 °C, 45 °C and 65 °C, respectively, while no metabolic activity was observed at 75 °C. The sugars were completely utilized during the 48 h temperature shift to 35 °C but not at 65 °C and 45 °C. At the end of the second cycle after the different temperature shifts, the H2 yield obtained was 96.5, 91.6, 79.9 and 54.1% (second cycle after temperature shift to 35 °C, 45 °C, 65 °C and 75 °C, respectively) when compared to the average H2 yield produced in the control at 55 °C. Characterization of the microbial communities present in the control culture at 55 °C showed the predominance of Thermoanaerobacteriales, Clostridiales and Bacilliales. The microbial community composition differed based on the fluctuation temperature with Thermoanaerobacteriales being most dominant during the upward temperature fluctuations and Clostridiales being the most dominant during the downward temperature fluctuations.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Bio- and Circular Economy, INRA
Contributors: Okonkwo, O., Escudié, R., Bernet, N., Mangayil, R., Lakaniemi, A., Trably, E.
Pages: 8028-8037
Publication date: 29 Mar 2019
Peer-reviewed: Yes

Publication information

Journal: International Journal of Hydrogen Energy
Volume: 44
Issue number: 16
ISSN (Print): 0360-3199
Original language: English

Research output: Contribution to journalArticleScientificpeer-review

Thiocyanate precursor impact on the formation of cobalt complexes: Synthesis and characterization

Two new thiocyanate complexes have been synthesized with two different thiocyanate anion sources using 1-(2-Pyrimidyl) piperazine andCoCl2.6H2O. These compounds were characterized by single X-ray diffraction, FTIR, UV-Visible and TGA-DTA. The antibacterial activity was also examined. The XRD showed that compounds 1 and 2 crystallized into monoclinic and orthorhombic systems respectively. In compound 1, cobalt is surrounded by two isothiocyanate anions and two nitrogen-amides, while in compound 2 it is surrounded by four isothiocyanate ligands and a separate protonated amide. Different interactions packed the system through N-H···S, N-H···O and O-H ···S hydrogen bonds forming a ring. Gap energy determination revealed two diverse behaviors, the first being characteristic of a semiconductor and the second of an insulator. In the 10-500 °C range, the thermal behaviors were investigated and showed the decomposition of the two complexes with metal complexes residues. The antibacterial analysis presented a weak performance.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering
Contributors: Hannachi, A., Valkonen, A., Rzaigui, M., Smirani, W.
Pages: 222-230
Publication date: 15 Mar 2019
Peer-reviewed: Yes
Early online date: 30 Dec 2018

Publication information

Journal: Polyhedron
Volume: 161
ISSN (Print): 0277-5387
Original language: English
Keywords: Thiocyanate precursor, Metal complexes, Crystal structures
Source: Bibtex
Source ID: urn:57e8c491b3071e3adc8ce62c0a54169f

Research output: Contribution to journalArticleScientificpeer-review

Synthetic metabolic pathway for the production of 1-alkenes from lignin-derived molecules

Background: Integration of synthetic metabolic pathways to catabolically diverse chassis provides new opportunities for sustainable production. One attractive scenario is the use of abundant waste material to produce a readily collectable product, which can reduce the production costs. Towards that end, we established a cellular platform for the production of semivolatile medium-chain α-olefins from lignin-derived molecules: we constructed 1-undecene synthesis pathway in Acinetobacter baylyi ADP1 using ferulate, a lignin-derived model compound, as the sole carbon source for both cell growth and product synthesis. Results: In order to overcome the toxicity of ferulate, we first applied adaptive laboratory evolution to A. baylyi ADP1, resulting in a highly ferulate-tolerant strain. The adapted strain exhibited robust growth in 100 mM ferulate while the growth of the wild type strain was completely inhibited. Next, we expressed two heterologous enzymes in the wild type strain to confer 1-undecene production from glucose: a fatty acid decarboxylase UndA from Pseudomonas putida, and a thioesterase 'TesA from Escherichia coli. Finally, we constructed the 1-undecene synthesis pathway in the ferulate-tolerant strain. The engineered cells were able to produce biomass and 1-undecene solely from ferulate, and excreted the product directly to the culture headspace. Conclusions: In this study, we employed a bacterium Acinetobacter baylyi ADP1 to integrate a natural aromatics degrading pathway to a synthetic production route, allowing the upgradation of lignin derived molecules to value-added products. We developed a highly ferulate-tolerant strain and established the biosynthesis of an industrially relevant chemical, 1-undecene, solely from the lignin-derived model compound. This study reports the production of alkenes from lignin derived molecules for the first time and demonstrates the potential of lignin as a sustainable resource in the bio-based synthesis of valuable products.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Bio- and Circular Economy
Contributors: Luo, J., Lehtinen, T., Efimova, E., Santala, V., Santala, S.
Number of pages: 13
Publication date: 11 Mar 2019
Peer-reviewed: Yes

Publication information

Journal: Microbial Cell Factories
Volume: 18
Issue number: 1
Article number: 48
ISSN (Print): 1475-2859
Original language: English
ASJC Scopus subject areas: Biotechnology, Bioengineering, Applied Microbiology and Biotechnology
Keywords: 1-Alkenes, Acinetobacter baylyi, Adaptive laboratory evolution, Ferulate, Lignin
Source: Scopus
Source ID: 85062867820

Research output: Contribution to journalArticleScientificpeer-review

Vertical stratification of bacteria and archaea in sediments of a small boreal humic lake

Although sediments of small boreal humic lakes are important carbon stores and greenhouse gas sources, the composition and structuring mechanisms of their microbial communities have remained understudied. We analyzed the vertical profiles of microbial biomass indicators (PLFAs, DNA and RNA) and the bacterial and archaeal community composition (sequencing of 16S rRNA gene amplicons and qPCR of mcrA) in sediment cores collected from a typical small boreal lake. While microbial biomass decreased with sediment depth, viable microbes (RNA and PLFA) were present all through the profiles. The vertical stratification patterns of the bacterial and archaeal communities resembled those in marine sediments with well-characterized groups (e.g. Methanomicrobia, Proteobacteria, Cyanobacteria, Bacteroidetes) dominating in the surface sediment and being replaced by poorly-known groups (e.g. Bathyarchaeota, Aminicenantes and Caldiserica) in the deeper layers. The results also suggested that, similar to marine systems, the deep bacterial and archaeal communities were predominantly assembled by selective survival of taxa able to persist in the low energy conditions. Methanotrophs were rare, further corroborating the role of these methanogen-rich sediments as important methane emitters. Based on their taxonomy, the deep-dwelling groups were putatively organo-heterotrophic, organo-autotrophic and/or acetogenic and thus may contribute to changes in the lake sediment carbon storage.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Department of Biological and Environmental Science, Jyväskylän yliopisto, University of Eastern Finland
Contributors: Rissanen, A. J., Peura, S., Mpamah, P. A., Taipale, S., Tiirola, M., Biasi, C., Mäki, A., Nykänen, H.
Publication date: 1 Mar 2019
Peer-reviewed: Yes

Publication information

Journal: FEMS Microbiology Letters
Volume: 366
Issue number: 5
ISSN (Print): 0378-1097
Original language: English
ASJC Scopus subject areas: Microbiology, Molecular Biology, Genetics
Keywords: 16S rRNA, archaea, bacteria, biomass, lake, sediment
Electronic versions: 
Source: Scopus
Source ID: 85066419815

Research output: Contribution to journalArticleScientificpeer-review

Quantitative Sequential Photoenergy Conversion Process from Singlet Fission to Intermolecular Two-Electron Transfers Utilizing Tetracene Dimer

Singlet fission (SF) theoretically enables the performance of the sequential photoenergy conversion process starting from the singlet state and leading to electron transfer (ET) with the radical ion pair quantum yield approaching 200%. Additionally, the long lifetime of the triplet state opens the possibility for an intermolecular ET process in a diffusion-limited reaction. However, the quantitative two-electron transfer process through SF has yet to be reported. Herein we demonstrate the quantitative sequential process involving SF and leading to intermolecular two-electron transfers using 2,2′-biphenyl-bridged tetracene dimer (Tet-BP-Tet: SF and electron donor) and chloranil (Ch: electron acceptor). The high-yield and long-lived individual triplet excited states of Tet-BP-Tet by SF (ΦT = 175 ± 5% and τT = 0.29 ms) resulted in the quantitative two-electron transfer process (ΦET = 173 ± 5%) with Ch in benzonitrile.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials
Contributors: Nakamura, S., Sakai, H., Nagashima, H., Kobori, Y., Tkachenko, N. V., Hasobe, T.
Number of pages: 6
Pages: 26-31
Publication date: 11 Jan 2019
Peer-reviewed: Yes
Early online date: 20 Nov 2018

Publication information

Journal: ACS Energy Letters
Volume: 4
Issue number: 1
ISSN (Print): 2380-8195
Original language: English
Source: RIS
Source ID: urn:9E96397B0FF697D1EB23606A29362AF2

Research output: Contribution to journalLetterScientificpeer-review

The economics of renewable CaC2 and C2H2 production from biomass and CaO

This article presents the economics of a bio-based CaC2/C2H2 production concept plant. The aim of the research was to study if renewable CaC2/C2H2 production could be competitive in comparison with current technologies. The starting point was to integrate a wood char production unit into a combined heat and power (CHP) plant with a bubbling fluidized bed (BFB) boiler. The wood char was reacted with CaO in an electric arc furnace (EAF). The production costs of the CaC2 were determined based on the wood char production costs as well as the EAF electric power consumption. The results showed that the C2H2 yield (18%) is similar to the current fossil-based production. However, the production costs proved to be even higher than the current selling prices of CaC2 and C2H2. With the chosen basic feedstock (20 €/MWh) and electricity prices (45 €/MWh) the production costs of CaC2 were calculated to be 725 €/t and for C2H2 1805 €/t. The cost effectiveness of the concept plant was determined using the payback time method including the time value of money. The break even selling prices were 747–920 €/t for the CaC2 and 1940–3015 €/t for C2H2 depending on the desired payback time (4–30 years). The key factors in the production costs of CaC2 and C2H2 are the price of electricity and the electrical efficiency of the EAF. The results also showed that recycling the Ca at the site could save up to 48% in fresh Ca material costs.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Test Rig Finland, Inc.
Contributors: Pääkkönen, A., Tolvanen, H., Kokko, L.
Number of pages: 9
Pages: 40-48
Publication date: 1 Jan 2019
Peer-reviewed: Yes
Early online date: 10 Nov 2018

Publication information

Journal: Biomass and Bioenergy
Volume: 120
ISSN (Print): 0961-9534
Original language: English
ASJC Scopus subject areas: Forestry, Renewable Energy, Sustainability and the Environment, Agronomy and Crop Science, Waste Management and Disposal
Keywords: /C, H, Poly-generation, Renewable CaC, Renewable chemicals, Techno-economic evaluation
Source: Scopus
Source ID: 85056214971

Research output: Contribution to journalArticleScientificpeer-review

An Artificial Nocturnal Flower via Humidity-Gated Photoactuation in Liquid Crystal Networks

Beyond their colorful appearances and versatile geometries, flowers can self-shape-morph by adapting to environmental changes. Such responses are often regulated by a delicate interplay between different stimuli such as temperature, light, and humidity, giving rise to the beauty and complexity of the plant kingdom. Nature inspires scientists to realize artificial systems that mimic their natural counterparts in function, flexibility, and adaptation. Yet, many of the artificial systems demonstrated to date fail to mimic the adaptive functions, due to the lack of multi-responsivity and sophisticated control over deformation directionality. Herein, a new class of liquid-crystal-network (LCN) photoactuators whose response is controlled by delicate interplay between light and humidity is presented. Using a novel deformation mechanism in LCNs, humidity-gated photoactuation, an artificial nocturnal flower is devised that is closed under daylight conditions when the humidity level is low and/or the light level is high, while it opens in the dark when the humidity level is high. The humidity-gated photoactuators can be fueled with lower light intensities than conventional photothermal LCN actuators. This, combined with facile control over the speed, geometry, and directionality of movements, renders the “nocturnal actuator” promising for smart and adaptive bioinspired microrobotics.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Eindhoven University of Technology
Contributors: Wani, O. M., Verpaalen, R., Zeng, H., Priimagi, A., Schenning, A. P.
Publication date: Jan 2019
Peer-reviewed: Yes
Early online date: 2018

Publication information

Journal: Advanced Materials
Volume: 31
Issue number: 2
Article number: 1805985
ISSN (Print): 0935-9648
Original language: English
ASJC Scopus subject areas: Materials Science(all), Mechanics of Materials, Mechanical Engineering
Keywords: actuator, azobenzene, bioinspired, humidity, light, liquid crystal, multi-responsive
Source: Scopus
Source ID: 85056318113

Research output: Contribution to journalArticleScientificpeer-review

A Pentacene-based Nanotube Displaying Enriched Electrochemical and Photochemical Activities

Unlike previously well-studied, acyclic pentacene oligomers, the first synthesis of a cyclic pentacene trimer with a fixed tubular conformation is reported. A short-step synthesis starting from common pentacenequinone yielded the target molecule with a 1.5 nanometer length and a subnanometer pore. Steady-state spectroscopic analyses revealed that the close proximity of the non-conjugated, three pentacene chromophores allows the nanotube to display stepwise electrochemical/chemical oxidation characteristics. Furthermore, time-resolved transient absorption measurements elucidated the generation of an excited triplet state of the nanotube, with high quantum yield reaching about 180 % through intramolecular singlet fission and a very long triplet lifetime.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Tokyo Institute of Technology, University of Yamanashi, Keio University
Contributors: Kuroda, K., Yazaki, K., Tanaka, Y., Akita, M., Sakai, H., Hasobe, T., Tkachenko, N. V., Yoshizawa, M.
Pages: 1115-1119
Publication date: Jan 2019
Peer-reviewed: Yes
Early online date: 2018

Publication information

Journal: Angewandte Chemie - International Edition
Volume: 58
Issue number: 4
ISSN (Print): 1433-7851
Original language: English
ASJC Scopus subject areas: Catalysis, Chemistry(all)
Keywords: macrocycles, nanotubes, pentacene, singlet fission, triplet states
Source: Scopus
Source ID: 85059193866

Research output: Contribution to journalArticleScientificpeer-review

Charge carrier dynamics in tantalum oxide overlayered and tantalum doped hematite photoanodes

We employ atomic layer deposition to prepare 50 nm thick hematite photoanodes followed by passivating them with a 0.5 nm thick Ta 2 O 5 -overlayer and compare them with samples uniformly doped with the same amount of tantalum. We observe a three-fold improvement in photocurrent with the same onset voltage using Ta-overlayer hematite photoanodes, while electrochemical impedance spectroscopy under visible light irradiation shows a decreased amount of surface states under water splitting conditions. The Ta-doped samples have an even higher increase in photocurrent along with a 0.15 V cathodic shift in the onset voltage and decreased resistivity. However, the surface state capacitance for the Ta-doped sample is twice that of the reference photoanode, which implies a larger amount of surface hole accumulation. We further utilize transient absorption spectroscopy in the sub-millisecond to second timescale under operating conditions to show that electron trapping in both Ta 2 O 5 -passivated and Ta-doped samples is markedly reduced. Ultrafast transient absorption spectroscopy in the sub-picosecond to nanosecond timescale shows faster charge carrier dynamics and reduced recombination in the Ta-doped hematite photoanode resulting in the increased photoelectrochemical performance when compared with the Ta 2 O 5 -overlayer sample. Our results show that passivation does not affect the poor charge carrier dynamics intrinsic to hematite based photoanodes. The Ta-doping strategy results in more efficient electron extraction, solving the electron trapping issue and leading to increased performance over the surface passivation strategy.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Chemistry & Advanced Materials, Materials Science and Environmental Engineering, Physics, Research group: Surface Science
Contributors: Ruoko, T., Hiltunen, A., Iivonen, T., Ulkuniemi, R., Lahtonen, K., Ali-Löytty, H., Mizohata, K., Valden, M., Leskelä, M., Tkachenko, N. V.
Number of pages: 10
Pages: 3206-3215
Publication date: Jan 2019
Peer-reviewed: Yes

Publication information

Journal: Journal of Materials Chemistry A
Volume: 7
Issue number: 7
ISSN (Print): 2050-7488
Original language: English
ASJC Scopus subject areas: Chemistry(all), Renewable Energy, Sustainability and the Environment, Materials Science(all)
Electronic versions: 

Bibliographical note

INT=phys,"Ulkuniemi, Riina"

Source: Scopus
Source ID: 85061474749

Research output: Contribution to journalArticleScientificpeer-review

Acetotrophic Activity Facilitates Methanogenesis from LCFA at Low Temperatures: Screening from Mesophilic Inocula

The inoculum source plays a crucial role in the anaerobic treatment of wastewaters. Lipids are present in various wastewaters and have a high methanogenic potential, but their hydrolysis results in the production of long chain fatty acids (LCFAs) that are inhibitory to anaerobic microorganisms. Screening of inoculum for the anaerobic treatment of LCFA-containing wastewaters has been performed at mesophilic and thermophilic conditions. However, an evaluation of inocula for producing methane from LCFA-containing wastewater has not yet been conducted at low temperatures and needs to be undertaken. In this study, three inocula (one granular sludge and two municipal digester sludges) were assessed for methane production from LCFA-containing synthetic dairy wastewater (SDW) at low temperatures (10 and 20°C). A methane yield (based on mL-CH4/g-CODadded) of 86-65% with acetate and 45-20% with SDW was achieved within 10 days using unacclimated granular sludge, whereas the municipal digester sludges produced methane only at 20°C but not at 10°C even after 200 days of incubation. The acetotrophic activity in the inoculum was found to be crucial for methane production from LCFA at low temperatures, highlighting the role of Methanosaeta (acetoclastic archaea) at low temperatures. The presence of bacterial taxa from the family Syntrophaceae (Syntrophus and uncultured taxa) in the inoculum was found to be important for methane production from SDW at 10°C. This study suggests the evaluation of acetotrophic activity and the initial microbial community characteristics by high-throughput amplicon sequencing for selecting the inoculum for producing methane at low temperatures (up to 10°C) from lipid-containing wastewaters.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Bio- and Circular Economy, Natl. University of Ireland, Galway
Contributors: Singh, S., Rinta-Kanto, J., Kettunen, R., Lens, P., Collins, G., Kokko, M., Rintala, J.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: ARCHAEA
Volume: 2019
Article number: 1751783
ISSN (Print): 1472-3646
Original language: English

Research output: Contribution to journalArticleScientificpeer-review

Antibacterial polymer fibres by rosin compounding and melt-spinning

The antibacterial features of natural pine/spruce rosin are well established, yet the functionality in various thermoplastics has not been surveyed. This work focuses on the processing of industrial grade purified rosin mixed with polyethylene (PE), polypropylene (PP), polylactic acid (PLA), polyamide (PA)and corn starch based biopolymer (CS). Homopolymer masterbatches were extrusion-compounded and melt-spun to form fibres for a wide range of products, such as filters, reinforcements, clothing and medical textiles. Due to the versatile chemical structure of rosin, it was observed compatible with all the selected polymers. In general, the rosin-blended systems were shear-thinning in a molten condition. The doped fibres spun of PE and PP indicated adequate melt-spinning capability and proper mechanical properties in terms of ultimate strength and Young's modulus. The antibacterial response was found dependent on the selected polymer. Especially PE with a 10 wt% rosin content showed significant antibacterial effects against Escherichia coli DH5α and Staphylococcus aureus ATCC 12598 when analysed in the Ringer's solution for 24 h.

General information

Publication status: Accepted/In press
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Plastics and Elastomer Technology, Department of Microbiology, Bundesanstalt für Materialforschung und -prüfung (BAM), Premix Oy, Aalto University, COMP Centre of Excellence, University of Helsinki
Contributors: Kanerva, M., Puolakka, A., Takala, T. M., Elert, A. M., Mylläri, V., Jönkkäri, I., Sarlin, E., Seitsonen, J., Ruokolainen, J., Saris, P., Vuorinen, J.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Materials Today Communications
Article number: 100527
ISSN (Print): 2352-4928
Original language: English
ASJC Scopus subject areas: Materials Science(all), Mechanics of Materials, Materials Chemistry
Keywords: Antibacterial, Fibre, Melt spinning, Thermoplastics
Electronic versions: 

Bibliographical note

EXT="Mylläri, V."

Source: Scopus
Source ID: 85066275027

Research output: Contribution to journalArticleScientificpeer-review

Bio-hydrogen Production from Sewage Sludge: Screening for Pretreatments and Semi-continuous Reactor Operation

Abstract: The high volumes of sewage sludge produced have raised interests for simultaneous treatment and clean energy production, e.g. in the form of hydrogen. Pretreatment of sewage sludge is required to enhance microbial degradation and in turn hydrogen yield from sewage sludge. The potential of five substrate pretreatments, individually and in combinations, to increase biohydrogen production from mixed primary and secondary sewage sludge at four incubation pH (5, 7, 9, and 11) was studied in batch assays. Alkali + ultrasonication pretreatment increased the hydrogen production almost seven times (0.35 mmol H2/g VS) compared to untreated sewage sludge at initial pH 11. In general, higher hydrogen yields and lower acetate concentrations were obtained under alkaline conditions (pH 9 and 11), being more favorable for protein degradation and not favorable for hydrogen consumption via homoacetogenesis. Subsequently, fermentation of alkali + ultrasonication pretreated sewage sludge in a semi-continuous stirred tank reactor (CSTR) produced a maximum hydrogen yield of 0.1 mmol H2/g VS, three times higher than the yield obtained from alkali pretreated sludge. The gas produced in the CSTRs contained a low concentration of CO2 (< 5%), and is thus easily upgradable to biohydrogen. Graphic Abstract: [Figure not available: see fulltext.].

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Water Pollution Research Department, National Research Centre, Indian Institute of Technology Hyderabad, Natl. University of Ireland, Galway, Ain Shams University
Contributors: El-Qelish, M., Chatterjee, P., Dessì, P., Kokko, M., El-Gohary, F., Abo-Aly, M., Rintala, J.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Waste and Biomass Valorization
ISSN (Print): 1877-2641
Original language: English
ASJC Scopus subject areas: Environmental Engineering, Renewable Energy, Sustainability and the Environment, Waste Management and Disposal
Keywords: Alkali treatment, Continuously stirred tank reactor (CSTR), Dark fermentation, Pretreatment, Sewage sludge, Ultrasonication
Source: Scopus
Source ID: 85069208392

Research output: Contribution to journalArticleScientificpeer-review

Charge transfer dynamics in CsPbBr3 perovskite quantum dots-anthraquinone/fullerene (C60) hybrids

An advantage of colloidal quantum dots, particularly perovskite quantum dots (PQDs), as photoactive components is that they easily form complexes with functional organic molecules, which results in hybrids with enriched photophysical properties. Herein, we demonstrate the formation of stable ground state complexes of CsPbBr3 PQD with two widely used molecular electron acceptors, fullerene (C60) and anthraquinone, (AQ) which contain carboxylic anchor groups. Dynamics of the photo-induced electron transfer in the hybrids were compared. The use of carboxylic groups for binding results in stable complex formation and their photophysical properties depend on the ratio of components but not the absolute concentrations (up to micromolar concentrations). Time-resolved transient absorption (TA) spectroscopy shows that in both cases, a charge separated (CS) state is formed. Data analysis was aimed to evaluate the CS time constant in ideal one-to-one complexes and was found to be in the range of 30-190 ps. The CS state of PQD-AQ complexes recombines directly to the ground state in roughly one microsecond. Recombination of the CS state of PQD-C60 is more complex and points to strong inhomogeneity of these complexes. Majority of the CS states relax by first forming the C60 triplet state.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering
Contributors: Mandal, S., George, L., Tkachenko, N. V.
Number of pages: 8
Pages: 862-869
Publication date: 2019
Peer-reviewed: Yes
Early online date: 10 Dec 2018

Publication information

Journal: Nanoscale
Volume: 11
Issue number: 3
ISSN (Print): 2040-3364
Original language: English
ASJC Scopus subject areas: Materials Science(all)
Source: Scopus
Source ID: 85060171357

Research output: Contribution to journalArticleScientificpeer-review

Effect of macro- and micro-nutrients addition during anaerobic mono-digestion of grass silage in leach-bed reactors

The effect of macro- (NH4Cl) (set I) and micro-nutrients (Fe, Ni, Co and Mo) (set II) addition on chemical oxygen demand (COD) solubilisation during anaerobic mono-digestion of grass silage was investigated in two sets of leach bed reactor experiments at 35°C. Results showed that addition of NH4Cl and micro-nutrients improved COD solubilisation by 18% (0.56 g SCOD g−1 volatile solids) and 7% (0.45 g SCOD g−1 VS), respectively than control. About 20–50% of the added micro-nutrients were bioavailable in the produced leachates, while the rest (50–80%) were adsorbed onto the grass silage. Results of biological methane potential assays showed that, specific methane yields of grass silage were improved by 17% (0.36 ± 0.02 m3 CH4 kg−1 VSadded) when NH4Cl was supplemented while Fe, Ni, Co and Mo addition improved methane yields by 15% (0.33 ± 0.005 m3 CH4 kg−1 VSadded) when compared to control.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, International Crops Research Institute for the Semi-Arid Tropics, Griffith University, Jyväskylän yliopisto
Contributors: Jagadabhi, P. S., Kaparaju, P., Väisänen, A., Rintala, J.
Number of pages: 12
Pages: 418-429
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Environmental Technology
Volume: 40
Issue number: 4
ISSN (Print): 0959-3330
Original language: English
ASJC Scopus subject areas: Environmental Chemistry, Water Science and Technology, Waste Management and Disposal
Keywords: anaerobic digestion, grass silage, Leach bed reactor, methane, micro-nutrients
Source: Scopus
Source ID: 85032370604

Research output: Contribution to journalArticleScientificpeer-review

Exclusive occurrence of photoinduced energy transfer and switching of its direction by rectangular π-extension of nanographenes

As structure defined cutouts of the graphene lattice, nanographene molecules have gained plenty of attention because of their high potential for versatile applications in organic electronics and energy conversion devices and as ideal model systems for the better understanding of intrinsic structure-property correlations of graphenes. In this study, well-defined nanographenes with sp2 carbon networks of different sizes, hexa-peri-hexabenzocoronene (HBC) and its rectangularly π-extended version, a short graphene nanoribbon (GNR), have been covalently functionalized with photoactive porphyrin molecules. On the basis of their spectroscopic studies, the photodynamics of the porphyrin-linked nanographenes was found to be influenced substantially by the size of the nanographenes. Photoexcitation of the porphyrin-HBC linked system led to exclusive energy transfer (EnT) from the first singlet excited state (S1) of the nanographene to the porphyrin, whereas opposite selective EnT occurred from the first and second singlet excited states (S1 and S2) of the porphyrin to the nanographene in the porphyrin-GNR linked system. In particular, ultrafast efficient EnTs from both the S2 and S1 states of the porphyrin to GNR mimic the corresponding ultrafast EnTs from the S2 and S1 states of carotenoids to chlorophylls in light-harvesting systems of natural photosynthesis. Such unique photophysical properties will be useful for the rational design of carbon-based photofunctional nanomaterials for optoelectronics and solar energy conversion devices.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Chemistry & Advanced Materials, Kyoto University, Institute for Integrated Cell-Material Sciences
Contributors: Umeyama, T., Hanaoka, T., Yamada, H., Namura, Y., Mizuno, S., Ohara, T., Baek, J., Park, J., Takano, Y., Stranius, K., Tkachenko, N. V., Imahori, H.
Number of pages: 9
Pages: 6642-6650
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Chemical Science
Volume: 10
Issue number: 27
ISSN (Print): 2041-6520
Original language: English
ASJC Scopus subject areas: Chemistry(all)
Electronic versions: 
Source: Scopus
Source ID: 85068830304

Research output: Contribution to journalArticleScientificpeer-review

Influence of titanium dioxide surface activation on the performance of mesoscopic perovskite solar cells

Perovskite solar cells with record efficiencies already above 24% are a highly promising clean energy technology. However, the reproducibility in their fabrication has proven to be challenging and needs more attention. Here we demonstrate that surface activation of the mesoscopic titanium dioxide (TiO2) scaffold, utilized in the two-step perovskite synthesis process, significantly affects the final device performance. Irradiating the mesostructured substrate with ultraviolet (UV) light prior to lead iodide (PbI2) deposition has a positive effect on the short-circuit current density and on the overall device performance (leading to a >20% increase in efficiency in our devices). As most of the UV light is absorbed in the topmost TiO2 layer, the interior of the scaffold remains less activated. This results in a sparsely packed PbI2 structure that facilitates an efficient conversion to the perovskite, while the activated topmost surface improves the perovskite capping layer. On the contrary, plasma treatment of the scaffold also activates the interior parts of the scaffold, which leads to a dense PbI2 structure that hampers the conversion and causing a >25% efficiency drop. We show that also minor changes in the surface properties of the mesoporous TiO2 scaffold can affect the device performance, which could explain some of the large efficiency variations observed between laboratories.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Åbo Akademi, Åbo Akademi University, Aalto University
Contributors: Masood, M. T., Weinberger, C., Qudsia, S., Rosqvist, E., Sandberg, O., Nyman, M., Sánden, S., Vivo, P., Aitola, K., Lund, P. D., Österbacka, R., Smått, J.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Thin Solid Films
Volume: 686
Article number: 137418
ISSN (Print): 0040-6090
Original language: English

Research output: Contribution to journalArticleScientificpeer-review

Low-dimensional formamidinium lead perovskite architectures via controllable solvent intercalation

We report the formation of a new class of solvent-intercalated two-dimensional (SI-2D) formamidinium lead halide perovskites. They can be mixed with three-dimensional (3D) stoichiometric perovskites by controlling the ratio of the precursor solutions. The composite leads to greatly improved photoluminescence quantum yield (PLQY) over the 3D compound. The enhanced PLQY is attributed to a type-I band alignment between the 3D and SI-2D, as revealed by first-principles calculations, which results in confined excitons with enhanced radiative recombination. The films exhibited excellent thermal and air stability retaining PLQY > 20% over 2 months in ambient conditions. Assemblies of halide perovskites with mixed dimensionality offer a pathway to enhance optoelectronic performance and device lifetimes.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Korea Advanced Institute of Science and Technology (KAIST), Yonsei University
Contributors: Shin, M., Kim, J., Jung, Y. K., Ruoko, T., Priimagi, A., Walsh, A., Shin, B.
Number of pages: 7
Pages: 3945-3951
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Journal of Materials Chemistry C
Volume: 7
Issue number: 13
ISSN (Print): 2050-7534
Original language: English
ASJC Scopus subject areas: Chemistry(all), Materials Chemistry
Source: Scopus
Source ID: 85064717293

Research output: Contribution to journalArticleScientificpeer-review

Metabolic profiling of water-soluble compounds from the extracts of dark septate endophytic fungi (DSE) isolated from scots pine (Pinus sylvestris L.) seedlings using UPLC–orbitrap–MS

Endophytes are microorganisms living inside plant hosts and are known to be beneficial for the host plant vitality. In this study, we isolated three endophytic fungus species from the roots of Scots pine seedlings growing on Finnish drained peatland setting. The isolated fungi belonged to dark septate endophytes (DSE). The metabolic profiles of the hot water extracts of the fungi were investigated using Ultrahigh Performance Liquid Chromatography with Diode Array Detection and Electron Spray Ionization source Mass Spectrometry with Orbitrap analyzer (UPLC–DAD–ESI–MS–Orbitrap). Out of 318 metabolites, we were able to identify 220, of which a majority was amino acids and peptides. Additionally, opine amino acids, amino acid quinones, Amadori compounds, cholines, nucleobases, nucleosides, nucleotides, siderophores, sugars, sugar alcohols and disaccharides were found, as well as other previously reported metabolites from plants or endophytes. Some differences of the metabolic profiles, regarding the amount and identity of the found metabolites, were observed even though the fungi were isolated from the same host. Many of the discovered metabolites have been described possessing biological activities and properties, which may make a favorable contribution to the host plant nutrient availability or abiotic and biotic stress tolerance.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Bio- and Circular Economy, Natural Resources Institute Finland (Luke), Turku University of Applied Science, University of Helsinki, School of Chemical Engineering, Aalto University
Contributors: Tienaho, J., Karonen, M., Muilu–Mäkelä, R., Wähälä, K., Denegri, E. L., Franzén, R., Karp, M., Santala, V., Sarjala, T.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Molecules
Volume: 24
Issue number: 12
Article number: 2330
ISSN (Print): 1420-3049
Original language: English
ASJC Scopus subject areas: Analytical Chemistry, Chemistry (miscellaneous), Molecular Medicine, Pharmaceutical Science, Drug Discovery, Physical and Theoretical Chemistry, Organic Chemistry
Keywords: Acephala applanata, Coniochaeta mutabilis, Endophytes, Endophytic fungi, Humicolopsis cephalosporioides, Metabolites, Peptides, Phialocephala fortinii, Scots pine, UPLC–MS
Electronic versions: 

Bibliographical note

EXT="Franzén, Robert"

Source: Scopus
Source ID: 85068104207

Research output: Contribution to journalArticleScientificpeer-review

Multiphoton Excitation of CsPbBr3 Perovskite Quantum Dots (PQDs): How Many Electrons Can One PQD Donate to Multiple Molecular Acceptors?

Metastable multiexcitonic states (MESs) of semiconductor quantum dots can be involved in multielectron transfer reactions, which opens new perspectives in nanomaterials-based optoelectronic applications. Herein, we demonstrate the generation of a MES in CsPbBr3 perovskite quantum dots (PQDs) and its dissociation dynamics through multiple electron transfers to molecular electron acceptors, anthraquinones (AQs), bound to the PQD surface by a carboxylic anchor. As many as 14 excitons are produced at an excitation density of roughly 220 μJ cm-2 without detectable PQD degradation. Addition of AQ results in the formation of PQD-AQ hybrids with excess of AQs (PQD:AQ ≈ 1:20), which opens the possibility of multielectron transfer acts from MES to AQs. We found that the electron transfer saturates after roughly five transfer acts and that the first electron transfer (ET) time constant is as short as 1 ps. However, each ET increases the Coulomb potential barrier for the next ET, which decreases the rate of ET, resulting in a saturation after five ETs.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Bio- and Circular Economy, Materials Science and Environmental Engineering
Contributors: Mandal, S., Tkachenko, N. V.
Number of pages: 7
Pages: 2775-2781
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry Letters
ISSN (Print): 1948-7185
Original language: English
ASJC Scopus subject areas: Materials Science(all), Physical and Theoretical Chemistry
Electronic versions: 
Source: Scopus
Source ID: 85066897133

Research output: Contribution to journalArticleScientificpeer-review

O2-requiring molecular reporters of gene expression for anaerobic microorganisms

Many genetic reporter systems require molecular oxygen; therefore, the use of reporter genes to study molecular mechanisms in anaerobic microorganisms has been hampered by the lack of convenient reporting systems. We describe reporter gene whole cell-based biosensor systems based on luciferase genes and the associated oxygen-requiring enzymes. By using two different oxygen-dependent reporters, insect and bacterial luciferases, and two bacterial hosts, Gram (+) Bifidobacterium longum and Gram (-) Escherichia coli, we show that the enzymes can be used in gene expression studies of anaerobic bacteria. E. coli, a facultative anaerobe, was grown both in aerobic and anaerobic conditions with an arabinose-inducible expression system. We show that a short treatment time of few minutes in ambient atmosphere is sufficient to detect light emission from living cells that is directly proportional to the number of cells and to the inducer concentration. The induction levels were the same in both the aerobically and anaerobically cultured cells. Similar results were obtained in the case of B. longum cultured in anaerobic conditions.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, Università degli Studi di Milano
Contributors: Guglielmetti, S., Santala, V., Mangayil, R., Ciranna, A., Karp, M. T.
Number of pages: 6
Pages: 1-6
Publication date: 2019
Peer-reviewed: Yes
Early online date: 20 Sep 2018

Publication information

Journal: Biosensors and Bioelectronics
Volume: 123
ISSN (Print): 0956-5663
Original language: English
ASJC Scopus subject areas: Biotechnology, Biophysics, Biomedical Engineering, Electrochemistry
Keywords: Bioluminescence, Gram (+), Gram (-), Luciferase, Arabinose induction
Electronic versions: 
Source: Scopus
Source ID: 85053858794

Research output: Contribution to journalArticleScientificpeer-review

Photoreactions of macrocyclic dyes on (1010) wurtzite surface – Interplay between conformation and electronic effects

Macrocyclic dyes such as phthalocyanine and porphyrin molecules are modeled on (10110) wurzite surfaces using the DFT and molecular dynamics approaches. It is found that the single dye anchored on the wurtzite surface stabilizes in an inclined geometry with its core facing the surface at a tilting angle of ca 60 . The tilting of the dye relative to the crystal surface has a dual effect on the charge transfer from a chromophore to the semiconductor. Increasing the tilting angle leads to a stronger coupling between the lowest level of the semiconductor conduction band and dye’s LUMO, thus raising the tunneling probability of the electron injection. By contrast, the electrostatic interaction between units upon the tilting of macrocycles results in a lowering of the molecule LUMO level with respect to the conduction band minimum of the wurzite crystal, which may hinder the electron transfer. The type of a linker and peripheral substituents significantly affect the mutual conformation of the moieties, and their proper choice can facilitate the photoinduced charge transfer reactions.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Materials Science and Environmental Engineering, South-Ukrainian National University, Center for Innovation Technologies
Contributors: Golovanova, V. V., Nazarchuk, B. V., Postnyi, O. V., Rantala, T. T., Tkachenko, N. V., Golovanov, V. V.
Number of pages: 9
Pages: 63-71
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Ukrainian Journal of Physics
Volume: 64
Issue number: 1
ISSN (Print): 2071-0186
Original language: English
ASJC Scopus subject areas: Physics and Astronomy(all)
Keywords: DFT, Electron transfer, Macrocyclic dyes, Wurzite

Bibliographical note

EXT="Golovanov, V. V."

Source: Scopus
Source ID: 85062936078

Research output: Contribution to journalArticleScientificpeer-review

Storing of exoelectrogenic anolyte for efficient microbial fuel cell recovery

Starting up a microbial fuel cell (MFC) requires often a long-term culture enrichment period, which is a challenge after process upsets. The purpose of this study was to develop low cost storage for microbial fuel cell enrichment culture to enable prompt process recovery after upsets. Anolyte of an operating xylose-fed MFC was stored at different temperatures and for different time periods. Storing the anolyte for one week or one month at +4 °C did not significantly affect power production, but lag time for power production was increased from 2 days to 3 or 5 days, respectively. One month storing at -20 °C increased the lag time to 7 days. The average power density in these MFCs varied between 1.2 and 1.7 W/m3. The share of dead cells (measured by live/dead staining) increased with storing time. After six-month storage the power production was insignificant. However, xylose removal remained similar in all cultures (99-100%) whilst volatile fatty acids production varied. The results indicate that fermentative organisms tolerated the long storage better than the exoelectrogens. As storing at +4 °C is less energy intensive compared to freezing, anolyte storage at +4 °C for maximum of one month is recommended as start-up seed for MFC after process failure to enable efficient process recovery.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy
Contributors: Haavisto, J. M., Lakaniemi, A., Puhakka, J. A.
Publication date: 2019
Peer-reviewed: Yes
Early online date: 2018

Publication information

Journal: Environmental Technology
Volume: 40
Issue number: 11
ISSN (Print): 0959-3330
Original language: English

Research output: Contribution to journalArticleScientificpeer-review

Structure and Dynamics of Thermosensitive pDNA Polyplexes Studied by Time-Resolved Fluorescence Spectroscopy

Combining multiple stimuli-responsive functionalities into the polymer design is an attractive approach to improve nucleic acid delivery. However, more in-depth fundamental understanding how the multiple functionalities in the polymer structures are influencing polyplex formation and stability is essential for the rational development of such delivery systems. Therefore, in this study the structure and dynamics of thermosensitive polyplexes were investigated by tracking the behavior of labeled plasmid DNA (pDNA) and polymer with time-resolved fluorescence spectroscopy using fluorescence resonance energy transfer (FRET). The successful synthesis of a heterofunctional poly(ethylene glycol) (PEG) macroinitiator containing both an atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain-transfer (RAFT) initiator is reported. The use of this novel PEG macroinitiator allows for the controlled polymerization of cationic and thermosensitive linear triblock copolymers and labeling of the chain-end with a fluorescent dye by maleimide-thiol chemistry. The polymers consisted of a thermosensitive poly(N-isopropylacrylamide) (PNIPAM, N), hydrophilic PEG (P), and cationic poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA, D) block, further referred to as NPD. Polymer block D chain-ends were labeled with Cy3, while pDNA was labeled with FITC. The thermosensitive NPD polymers were used to prepare pDNA polyplexes, and the effect of the N/P charge ratio, temperature, and composition of the triblock copolymer on the polyplex properties were investigated, taking nonthermosensitive PD polymers as the control. FRET was observed both at 4 and 37 °C, indicating that the introduction of the thermosensitive PNIPAM block did not compromise the polyplex structure even above the polymer's cloud point. Furthermore, FRET results showed that the NPD- and PD-based polyplexes have a less dense core compared to polyplexes based on cationic homopolymers (such as PEI) as reported before. The polyplexes showed to have a dynamic character meaning that the polymer chains can exchange between the polyplex core and shell. Mobility of the polymers allow their uniform redistribution within the polyplex and this feature has been reported to be favorable in the context of pDNA release and subsequent improved transfection efficiency, compared to nondynamic formulations.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Chemistry & Advanced Materials, Utrecht University, Helsinki University, Chemistry and Advanced Materials
Contributors: Fliervoet, L. A., Lisitsyna, E. S., Durandin, N. A., Kotsis, I., Maas-Bakker, R. F., Yliperttula, M., Hennink, W. E., Vuorimaa-Laukkanen, E., Vermonden, T.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Biomacromolecules
ISSN (Print): 1525-7797
Original language: English
ASJC Scopus subject areas: Bioengineering, Biomaterials, Polymers and Plastics, Materials Chemistry
Electronic versions: 
Source: Scopus
Source ID: 85073002500

Research output: Contribution to journalArticleScientificpeer-review

Sustainability of bioenergy in finland and globally – fact check

The sustainability of bioenergy has attracted recently a lot of debate and there has been critical arguments for and against the use of bioenergy. This presentation examines six international publications dealing with the use of bioenergy and collects systematically the allegations of bioenergy, as well as arguments for defending and restricting bioenergy use in the publications. Some of the most controversial arguments are analyzed more thoroughly and they are subjected to fact checking by comparing arguments with sources in scientific literature. At the same time, the preconditions, restrictions, and assumptions that can be used to modify the claims to favor desired arguments are identified. The study finds that there are several problems that can be criticized towards the arguments. Arguments can be justified, among others, by looking at the situation over different time periods or by emphasizing the maximization of short-term or long-term climate benefits. Different values can be selected from initial data, whereupon their own argument can be confirmed.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Materials Science and Environmental Engineering, Lappeenranta University of Technology, Tampere University
Contributors: Vakkilainen, E., Konttinen, J., Orasuo, V., Aalto, P.
Number of pages: 2
Pages: 1634-1635
Publication date: 2019

Host publication information

Title of host publication: 27th European Biomass Conference and Exhibition, EUBCE 2019
Publisher: ETA-Florence Renewable Energies

Publication series

Name: European Biomass Conference and Exhibition Proceedings
ISSN (Print): 2282-5819
ASJC Scopus subject areas: Agronomy and Crop Science, Forestry, Renewable Energy, Sustainability and the Environment, Waste Management and Disposal
Keywords: Bioenergy, Carbon neutrality, Carbon sinks, Climate change, Fact check, Forest Biomass, Sustainability

Bibliographical note

jufoid=71903

Source: Scopus
Source ID: 85071067879

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Synthesis of 6,12-disubstituted methanodibenzo[b,f ][1,5]dioxocins: Pyrrolidine catalyzed self-condensation of 2′-Hydroxyacetophenones

The preparation of unprecedented 6,12-disubstituted methanodibenzo[b,f ][1,5]dioxocins from pyrrolidine catalyzed self-condensation of 2′-hydroxyacetophenones is herein described. This method provides easy access to this highly bridged complex core, resulting in construction of two C-O and two C-C bonds, a methylene bridge and two quaternary centers in a single step. The intricate methanodibenzo[b,f ][1,5]dioxocin compounds were obtained in up to moderate yields after optimization of the reaction conditions concerning solvent, reaction times and the use of additives. Several halide substituted methanodibenzo[b,f ][1,5]dioxocins could be prepared from correspondent 2′-hydroxyacetophenones.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Faculdade de Farmacia da Universidade de Lisboa, University of Jyvaskyla
Contributors: Assoah, B., Riihonen, V., Vale, J. R., Valkonen, A., Candeias, N. R.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Molecules
Volume: 24
Issue number: 13
Article number: 2405
ISSN (Print): 1420-3049
Original language: English
ASJC Scopus subject areas: Analytical Chemistry, Chemistry (miscellaneous), Molecular Medicine, Pharmaceutical Science, Drug Discovery, Physical and Theoretical Chemistry, Organic Chemistry
Keywords: 1,5-dioxocin, 20-hydroxyacetophenone, Enamine, Self-condensation
Electronic versions: 

Bibliographical note

EXT="Valkonen, Arto"
INT=msee,"Riihonen, Vesa"
INT=msee,"Vale, João R."

Source: Scopus
Source ID: 85068362408

Research output: Contribution to journalArticleScientificpeer-review

Volatile fatty acid adsorption on anion exchange resins: kinetics and selective recovery of acetic acid

The removal of volatile fatty acids was examined through adsorption on anion exchange resins in batch systems. During the initial screening step, granular activated carbon and 11 anion exchange resins were tested and the resins Amberlite IRA-67 and Dowex optipore L-493 were chosen for further investigation. The adsorption kinetics and diffusion mechanism and adsorption isotherms of the two resins for VFA were evaluated. Based on the selective adsorption capacity of the resins, a sequential batch process was tested to achieve separation of acetic acid from the VFA mixture and selective recoveries > 85% acetic acid and ~ 75% propionic acid was achieved.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Hydraulic and Environmental Engineering (IHE) Inst. for Water Education, Institute for Water Education
Contributors: Eregowda, T., Rene, E. R., Rintala, J., Lens, P. N.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Separation Science and Technology (Philadelphia)
ISSN (Print): 0149-6395
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all), Process Chemistry and Technology, Filtration and Separation
Keywords: anion-exchange resins, Brunauer-Emmett-Teller model, selective recovery, Volatile fatty acids
Source: Scopus
Source ID: 85065190589

Research output: Contribution to journalArticleScientificpeer-review

Zinc phthalocyanine activated by conventional indoor light makes a highly efficient antimicrobial material from regular cellulose

Zn phthalocyanine with improved synthesis suitable for bulk production shows extremely high antimicrobial efficacies even under weak indoor light. The dye-impregnated cellulose material inactivates over 99.996% of drug-resistant C. albicans, S. aureus and E. faecalis in just one hour exposure with consumer-grade fluorescent lamps and diodes.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Chemistry & Advanced Materials
Contributors: Grammatikova, N. E., George, L., Ahmed, Z., Candeias, N. R., Durandin, N. A., Efimov, A.
Pages: 4379-4384
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Journal of Materials Chemistry B
Volume: 7
Issue number: 28
ISSN (Print): 2050-750X
Original language: English
Source: ORCID
Source ID: /0000-0003-2414-9064/work/59045423

Research output: Contribution to journalArticleScientificpeer-review

Reversible photodoping of TiO2 nanoparticles

Observations on strong photochromic effect of crystalline TiO2 quantum dots (mean size ≈ 4 nm) are presented. The synthesized quantum dots consist of irregularly shaped anatase TiO2 nanoparticles (NPs) and are dispersed in butanol (8 % by mass). Obtained NPs exhibit a dramatic photo-response to UV light, enabling effective transmittance modula-tion of in a broad wavelength range extending from visible to near-infrared region, and even the thermal black body radiation regime beyond 10 μm. The exceptional photo-response is attributed to hole-scavenging by butanol, TiO2 self-reduction, injection of electrons to the conduction band, and consequent localized surface plasmon resonances in NPs. Observed optical effect is reversible and the initial high transmittance state can be restored simply by exposing the NPs to air. Applied NP synthesis route is economic and can be easily scaled for applications such as smart window technol-ogies.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Photonics, Research group: Surface Science, Univ Tartu, University of Tartu, University of Tartu Institute of Physics, Inst Phys, University of Tartu
Contributors: Joost, U., Sutka, A., Oja, M., Smits, K., Doebelin, N., Loot, A., Järvekülg, M., Hirsimäki, M., Valden, M., Nommiste, E.
Pages: 8968-8974
Publication date: 26 Dec 2018
Peer-reviewed: Yes
Early online date: 10 Dec 2018

Publication information

Journal: Chemistry of Materials
Volume: 30
Issue number: 24
ISSN (Print): 0897-4756
Ratings: 
  • Scopus rating (2018): CiteScore 9.92 SJR 4.224 SNIP 1.769
Original language: English
ASJC Scopus subject areas: Inorganic Chemistry, Materials Chemistry, Surfaces and Interfaces, Electronic, Optical and Magnetic Materials, Condensed Matter Physics
Keywords: tio2, nano, nanoparticle, photochromic, anatase, light, photonics, functional
URLs: 

Bibliographical note

INT=fot,"Joost, Urmas"

Research output: Contribution to journalArticleScientificpeer-review

Bioengineering optimization and microbial characterization of elemental sulfur-fueled denitrifying biofilms

Nowadays, the increasing human population and limited water resources create a demand for sustainable wastewater treatment technologies. Chemically synthesized elemental sulfur (S0)-based denitrification is an effective and cost-efficient biotechnology for nitrate (NO3-) removal from organic-deficient wastewaters. However, the hydrophobic properties of S0 limit its application for denitrification. Thus, the goal of this project is to optimize the performance and explore the treatment mechanisms of S0-fueled denitrification in biofilm systems, and the understanding of the associated microbial communities.

To address the limitation of the chemically synthesized S0-driven denitrification applications, S0 solubilization prior to S0-driven denitrification was studied in batch bioassays. The kinetic experiments showed that the achieved denitrification and denitritation rates were 20.9 and 10.7 mg N/L∙d, respectively. Microbiological analysis detected the presence of the Helicobacteraceae family onto S0 particles, that was likely responsible for the S0 solubilization. A mathematical model of microbially-catalyzed S0 hydrolysis and subsequent two-step denitrification was developed. The sensitivity analysis identified the dominance of the hydrolysis-related parameters, and suggested that microbially-catalyzed surface-based S0 hydrolysis is the rate-limiting step during S0-driven denitrification.

Autotrophic denitrification with biosulfur (ADBIOS), a by-product of biological gas desulfurization, was investigated in batch bioassays as an alternative technological solution for treating NO3- pollution in wastewaters. Denitrification and denitritation rates of 49.4 mg NO3--N/L·d and 73.0 mg NO2--N/L·d, respectively, were obtained. The Thiobacillus, Moheibacter and Thermomonas genera were dominating the ADBIOS microbial community.

Two duplicate moving-bed biofilm reactors (MBBRs) with AnoxKTM K1 (K1) and AnoxKTM Z-200 (Z-200) carriers were operated for 309 days. The effect of the nitrate loading rate on the ADBIOS performance was studied by decreasing hydraulic retention time (HRT) from 72 to 21 h. The denitrification rates of 236 and 234 mg NO3--N/L·d were achieved at an HRT of 24 h for K1 and an HRT of 21 h for Z-200 carrier, respectively. Based on RNA analysis, the same active bacteria, belonging to Thiobacillus, Truepera, Flavobacterium and Hyphomonas genera, were dominating MBBRs with K1 and Z-200 carriers.

General information

Publication status: Published
MoE publication type: G5 Doctoral dissertation (article)
Organisations: Chemistry and Bioengineering
Contributors: Kostrytsia, A.
Number of pages: 142
Publication date: 6 Dec 2018

Publication information

Original language: English
URLs: 

Research output: Book/ReportDoctoral thesisCollection of Articles

Experimental and Modeling Assessment of the Main Bio-physical-chemical mechanisms and Kinetics in High-solids Anaerobic Digestion of Organic Waste

The organic fraction of municipal solid waste (OFMSW) includes readily biodegradable wastes such as food waste, and slowly biodegradable wastes such as lignocellulosic materials. Anaerobic digestion (AD) is a mature treatment biotechnology in which OFMSW is decomposed to a mixture of methane (CH4) and carbon dioxide (CO2), known as biogas. Due to the elevated CH4 content (50 - 70 %), biogas can be used as a source of renewable energy. Moreover, AD yields also a partially stabilized digestate, allowing the recycle of nutrients back to agriculture.

High-solids anaerobic digestion (HS-AD) is a well-suited strategy to enhance the overall AD efficiency for OFMSW treatment. HS-AD is operated at a total solid (TS) content ≥ 10 %, permitting to reduce the reactor size and overall operational costs. Nonetheless, the TS increase can result into biochemical instability, and even reactor failure by acidification. Both the high organic load and the buildup of inhibitors can be responsible for the HS-AD instability. The most notable inhibitor in HS-AD of OFMSW is the free ammonia nitrogen (NH3). Therefore, a balance is often required between enhancing the HS-AD economy and the ‘undesired’ instability for OFMSW treatment.

This PhD research investigated the main bio-physical-chemical mechanisms and kinetics in HS-AD of OFMSW, with the aim to optimize the industrial application and maximize the kinetic rates. Laboratory-scale batch and semi-continuous experiments highlighted the main strengths and weaknesses of HS-AD. Simultaneously, the development of a HS-AD model permitted to condense the experimental knowledge about the main bio-physical-chemical effects occurring when increasing the TS content in HS-AD.

HS-AD batch experiments required a tradeoff between the initial TS, the inoculum-to-substrate ratio (ISR), the alkalinity and the nitrogen content, to assess the effects of increasing the initial TS content upon the methane yield, TS removal and chemical oxygen demand conversion. Particularly, a low ISR led to acidification, whereas the NH3 buildup led to volatile fatty acid (VFA) accumulation, reducing the methane yield, whether or not co-digestion of OFMSW with beech sawdust was used.

In semi-continuous experiments, HS-AD of OFMSW required a reduced effluent compared to the influent to counterbalance the organic mass removal associated to the biogas production. Nonetheless, mono-digestion of readily-biodegradable OFMSW could not sustain a TS ≥ 10 % without exacerbating the risk of substrate overload. Overloading was associated to the high biodegradability of OFMSW and the NH3 buildup. Thus, adding sawdust to OFMSW permitted to operate the reactors up to 30 % TS, due to the lower biodegradability and nitrogen content of lignocellulosic substrates.

As the main novelty of this PhD research, a HS-AD model based on the Anaerobic Digestion Model No.1 (ADM1) was developed. This model simulates the reactor mass and TS in HS-AD, in contrast of models focusing on ‘wet’ AD simulations (TS < 10 %). Moreover, the HS-AD model considers also the TS concentration effect on soluble species. A ‘non-ideal’ bio-physical-chemical module, modifying predominantly the acid-base equilibrium constants, was subsequently coupled to the HS-AD model. Noteworthy, HS-AD is often characterized by a high ionic strength (I ≥ 0.2 M), affecting the pH, NH3 concentration and CO2 liquid-gas transfer, as the most important triggers for HS-AD inhibition.

The HS-AD model calibration required multiple experimental datasets to circumvent parameter non-identifiability. The model calibration showed that HS-AD of OFMSW might be operated at I up to 0.9 M and NH3 concentrations up to 2.3 g N/L, particularly at higher TS contents (25 - 30 %). Moreover, the model calibration suggested that a reversible non-competitive NH3 inhibition should be further tested. Further HS-AD model developments (e.g. precipitation) were also recommended. All these results might aid in the optimization of HS-AD for organic waste treatment, renewable energy and nutrient recovery.

General information

Publication status: Published
MoE publication type: G5 Doctoral dissertation (article)
Organisations: Chemistry and Bioengineering
Contributors: Pastor Poquet, V.
Number of pages: 237
Publication date: 5 Dec 2018

Publication information

Original language: English
URLs: 

Research output: Book/ReportDoctoral thesisCollection of Articles

Optimization of fermentative biohydrogen production by Thermotoga neapolitana

Hydrogen has revealed a great potential as a versatile and non-polluting energy carrier of the future providing a high energy density and an efficiently conversion to usable power. Dark fermentation is one of the most promising biological production processes, but still has to overcome major challenges, most importantly low hydrogen production rates (HPRs) and hydrogen yields (HYs), before its industrial application becomes cost- and energy-efficient.

In this work, we aimed to optimize the hydrogen production via dark fermentation by Thermotoga neapolitana. The main objectives were to enhance the HPR and maintain a high HY using different approaches to counteract process limitations and prevent the most relevant inhibitions. Furthermore, a development of the industrially preferred continuous-flow process was projected.

An increase of the initial biomass concentration from 0.46 to 1.74 g cell dry weight (CDW)/L in batch bioassays resulted in a more than 2-fold enhancement of the HPR up to 654 (±30) mL/L/h (mL of hydrogen produced per L of volume of reactor per hour of reaction or per hour of liquid retention) without negatively affecting the HY. However, while the volumetric productivity increased the specific HPR (per unit of biomass) was negatively correlated with the HPR and the biomass concentration.

Subsequently, we investigated the supersaturation of hydrogen in the liquid phase (H2aq) in batch bioassays. At 100 rpm agitation H2aq supersaturated up to 3 times the equilibrium concentration. Increasing the agitation speed diminished the accumulation of H2aq until an equilibrium between the gas and liquid phase hydrogen was reached with 500 rpm agitation at low cell concentrations. A raise from 200 to 600 rpm gradually reduced H2aq from 21.9 (± 2.2) to 8.5 (± 0.1) mL/L and approximately doubled the HPR, revealing a direct correlation between the two parameters. Similarly, the addition of K1 carrier and H2-rich biogas recirculation (GaR) successfully counteracted the accumulation of H2aq. Accelerating the process by increasing the reactors biomass concentration up to 0.79 g CDW/L, GaR revealed to be more efficient in removing H2aq than 500 rpm agitation. The application of GaR at 300 and 500 rpm enhanced the HPR by approximately 260% up to 850 (± 71) mL/L/h, compared to a sole 300 rpm agitation, reaching a HY of 3.5 mol H2/mol glucose. We demonstrated that an insufficient gas-liquid mass transfer leads to the accumulation of H2aq which inhibits the yield but even more so the rate of dark fermentation.

In the final phase of this project we successfully maintained continuous-flow hydrogen production. Increasing the feed glucose concentration from 11.1 to 41.6 mM diminished the HY from 3.6 (± 0.1) to 1.4 (± 0.1) mol H2/mol glucose. The HPR increased concomitantly up to approximately 55 mL/L/h at 27.8 mM of glucose, whereas a further increase of feed glucose to 41.6 mM did not enhance the HPR and the acetic acid (AA) concentration. To investigate whether high levels of AA limited the process, the feed AA concentration was gradually increased. However, this revealed no negative effect on continuous dark fermentation up to 240 mM of feed AA and, throughout the 110 days of continuous fermentation, the HY increased by 47%. Decreasing the hydraulic retention time (HRT) from 24 to 7 h also led to a HPR enhancement from 82 (± 1) to 192 (± 4) mL/L/h, while decreasing the HY. Concomitantly, the H2aq accumulated, directly correlated to the HPR reaching 15.6 mL/L at an HRT of 7 h and 500 rpm agitation. The application of GaR efficiently counteracted the supersaturation of H2aq and allowed the highest HPR of 277 mL/L/h at a HRT of 5 h.

General information

Publication status: Published
MoE publication type: G5 Doctoral dissertation (article)
Organisations: Chemistry and Bioengineering
Contributors: Dreschke, G.
Number of pages: 124
Publication date: 5 Dec 2018

Publication information

Original language: English
URLs: 

Research output: Book/ReportDoctoral thesisCollection of Articles

Highly Efficient Energy Transfer Cassettes by Assembly of Boronic Acid Derived Salicylidenehydrazone Complexes

Energy transfer cassettes that build on the platform of boronic acid derived salicylidenehydrazone (BASHY) complexes were prepared. The functional flexibility of the BASHY chromophore was underpinned by its tunable role as energy donor or acceptor, integrated in compact and non‐conjugated bichromophoric dyads. The energy transfer is highly efficient (ΦET>0.95) and is assumed to proceed mainly via a through‐bond mechanism. Both constituent chromophores benefit mutually from their integration in the cassettes: a) The pseudo Stokes shift is increased to 110–200 nm; b) the antenna (donor) chromophore improves the light absorption of the acceptor chromophore; and c) the emission window of the BASHY chromophore is expanded in the BASHY‐Bodipy dye without using strategies that compromise the observation of high quantum yields. The application of the cassettes for the formulation of fluorescent polymeric nanoparticles, that can be internalized in cells and observed by fluorescence imaging, was demonstrated using the BASHY‐Bodipy dye as an example.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Chemistry & Advanced Materials, Chemistry and Bioengineering, Univ Lisbon, Fac Farm, Inst Invest Medicamento iMed ULisboa, Faculdade de Farmacia da Universidade de Lisboa, Universidad de Huelva
Contributors: Santos, F. M. F., Dominguez, Z., Alcaide, M. M., Matos, A. I., Florindo, H. F., R. Candeias, N., Gois, P. M. P., Pischel, U.
Pages: 1038-1045
Publication date: Dec 2018
Peer-reviewed: Yes
Early online date: 3 Sep 2018

Publication information

Journal: ChemPhotoChem
Volume: 2
Issue number: 12
ISSN (Print): 2367-0932
Original language: English

Research output: Contribution to journalArticleScientificpeer-review

Aminobenzylated 4-Nitrophenols as Antibacterial Agents Obtained from 5-Nitrosalicylaldehyde through a Petasis Borono-Mannich Reaction

Multidrug-resistant bacteria are one of the current biggest threats to public health and are responsible for most nosocomial infections. Herein, we report the efficient and facile synthesis of antibacterial agents aminoalkylphenols, derived from 5-nitrosalicyladehyde and prepared through a Petasis borono-Mannich multicomponent reaction. Minimum inhibitory concentrations (MICs) as low as 1.23 μM for a chlorine derivative were determined for multidrug-resistant Gram-positive bacteria, namely, Staphylococcus aureus and Enterococcus faecalis, two of the main pathogens responsible for infections in a hospital environment. The most promising antibacterial agents were further tested against eight strains of four Gram-positive species in order to elucidate their antibacterial broadness. In vitro cytotoxicity assays of the most active aminoalkylphenol revealed considerably lower toxicity against mammalian cells, as concentrations one order of magnitude higher than the determined MICs were required to induce human keratinocyte cell death. The phenol moiety was verified to be important in deeming the antibacterial properties of the analyzed compounds, although no correlation between such properties and their antioxidant activity was observed. A density functional theory computational study substantiated the ability of aminoalkylphenols to serve as precursors of ortho-quinone methides.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, CBIOS-Universidade Lusófona Research Center for Biosciences and Health Technologies, National Institute of Health, Faculdade de Farmacia da Universidade de Lisboa
Contributors: Rimpiläinen, T., Andrade, J., Nunes, A., Ntungwe, E., Fernandes, A. S., Vale, J. R., Rodrigues, J., Gomes, J. P., Rijo, P., Candeias, N. R.
Number of pages: 12
Pages: 16191-16202
Publication date: 29 Nov 2018
Peer-reviewed: Yes

Publication information

Journal: ACS Omega
Volume: 3
Issue number: 11
ISSN (Print): 2470-1343
Ratings: 
  • Scopus rating (2018): CiteScore 2.54 SJR 0.754 SNIP 0.673
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all)
Electronic versions: 
Source: Scopus
Source ID: 85057603661

Research output: Contribution to journalArticleScientificpeer-review

Liquid Crystal Polymer Networks and Elastomers for Light-Fueled Robotics

Summary Liquid crystal (LC) polymer networks and elastomers are synthetic cross-linked polymer systems constituting liquid crystalline building blocks, or mesogens. This chapter provides an up-to-date overview of light- fueled LC network (LCN) robotics. It explains photoactuation and light robotics, and discusses the basic physics that a small-scale LCN robot encounters, as the forces at the microscale are very different from common everyday experience. The chapter also introduces the photoactuation mechanisms, making a comparison between photothermal and photochemical actuation strategies, which often times yield distinct actuation behavior and shape changes. Azobenzene-based photochemical actuators often times exhibit photoinduced bending as opposed to in-plane photocontraction. The chapter considers autonomous actuation, driven by dynamic light-response in the material, to adopt a significant role in the design of future LCN robots. Uniaxially aligned LCNs can undergo reversible contraction-expansion along the molecular director axis, thus presenting muscle-like motion under external stimulus.

General information

Publication status: Published
MoE publication type: A3 Part of a book or another research book
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials
Contributors: Zeng, H., Lahikainen, M., Wani, O. M., Berdin, A., Priimagi, A.
Number of pages: 30
Pages: 197-226
Publication date: 19 Nov 2018

Host publication information

Title of host publication: Photoactive Functional Soft Materials
Publisher: John Wiley & Sons, Ltd
Editor: Li, Q.
ISBN (Print): 978-3-527-34482-6
ISBN (Electronic): 978-3-527-81677-4
Keywords: elastomers, light-fueled robotics, liquid crystal polymer networks, photochemical actuation, photothermal actuation, small-scale robots, soft micro-robotics, uniaxial contraction, uniaxial expansion
Source: Bibtex
Source ID: urn:66e666ef0dccb2541602941e2c2fbc04

Research output: Chapter in Book/Report/Conference proceedingChapterScientificpeer-review

High-Yield Generation of Triplet Excited States by an Efficient Sequential Photoinduced Process from Energy Transfer to Singlet Fission in Pentacene-Modified CdSe/ZnS Quantum Dots

Singlet fission (SF) is expected to improve photoenergy conversion systems by generating two electrons from one photon. Pentacenes meet the energy-level matching condition between a singlet and two triplet states: [E(S1)≥2E(T1)]. However, the molar absorption coefficients of pentacenes in the approximately 400–500 nm region are limited, whereas quantum dots, such as CdSe/ZnS (QD), possess high fluorescence quantum yields and particle-size-dependent fluorescence wavelengths. Thus, a combination of QD (D) and pentacene (A) provides a system of both an enhanced light-harvesting efficiency throughout the solar spectrum and an efficient conversion of the harvested light into the triplet states by SF. Based on these points, m-phenylene-bridged triisopropylsilane (TIPS)-pentacene dimer-functionalized QD (denoted as m-(Pc)2-QD) was synthesized to examine the sequential photoinduced process from energy transfer to SF. In femtosecond transient absorption measurements, initial energy transfer from QD to pentacene (quantum yield: 87 %) and subsequent SF were efficiently observed. The quantum yield of triplet states of pentacene units (ΦΤ) based on the excitation of QD attained is 160±6.7 %.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Keio University
Contributors: Sakai, H., Inaya, R., Tkachenko, N. V., Hasobe, T.
Number of pages: 10
Pages: 17062-17071
Publication date: 16 Nov 2018
Peer-reviewed: Yes

Publication information

Journal: Chemistry - A European Journal
Volume: 24
Issue number: 64
ISSN (Print): 0947-6539
Ratings: 
  • Scopus rating (2018): CiteScore 4.77 SJR 1.842 SNIP 0.972
Original language: English
ASJC Scopus subject areas: Catalysis, Organic Chemistry
Keywords: energy transfer, pentacene, quantum dot, sequential photophysical process, singlet fission
Source: Scopus
Source ID: 85055548433

Research output: Contribution to journalArticleScientificpeer-review

Understanding Dissolution and Crystallization with Imaging: A Surface Point of View

The tendency for crystallization during storage and administration is the most considerable hurdle for poorly water-soluble drugs formulated in the amorphous form. There is a need to better detect often subtle and complex surface crystallization phenomena and understand their influence on the critical quality attribute of dissolution. In this study, the interplay between surface crystallization of the amorphous form during storage and dissolution testing, and its influence on dissolution behavior, is analyzed for the first time with multimodal nonlinear optical imaging (coherent anti-Stokes Raman scattering (CARS) and sum frequency generation (SFG)). Complementary analyses are provided with scanning electron microscopy, X-ray diffraction and infrared and Raman spectroscopies. Amorphous indomethacin tablets were prepared and subjected to two different storage conditions (30 °C/23% RH and 30 °C/75% RH) for various durations and then dissolution testing using a channel flow-through device. Trace levels of surface crystallinity previously imaged with nonlinear optics after 1 or 2 days of storage did not significantly decrease dissolution and supersaturation compared to the freshly prepared amorphous tablets while more extensive crystallization after longer storage times did. Multimodal nonlinear optical imaging of the tablet surfaces after 15 min of dissolution revealed complex crystallization behavior that was affected by both storage condition and time, with up to four crystalline polymorphs simultaneously observed. In addition to the well-known α- and ?-forms, the less reported metastable ?- and ?-forms were also observed, with the ?-form being widely observed in samples that had retained significant surface amorphousness during storage. This form was also prepared in the pure form and further characterized. Overall, this study demonstrates the potential value of nonlinear optical imaging, together with more established solid-state analysis methods, to understand complex surface crystallization behavior and its influence on drug dissolution during the development of amorphous drugs and dosage forms.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, University of Helsinki, University of Helsinki Faculty of Medicine, University of Otago
Contributors: Novakovic, D., Isomäki, A., Pleunis, B., Fraser-Miller, S. J., Peltonen, L., Laaksonen, T., Strachan, C. J.
Number of pages: 13
Pages: 5361-5373
Publication date: 5 Nov 2018
Peer-reviewed: Yes

Publication information

Journal: Molecular Pharmaceutics
Volume: 15
Issue number: 11
ISSN (Print): 1543-8384
Ratings: 
  • Scopus rating (2018): CiteScore 4.7 SJR 1.402 SNIP 1.165
Original language: English
ASJC Scopus subject areas: Molecular Medicine, Pharmaceutical Science, Drug Discovery
Keywords: amorphous, dissolution, indomethacin, nonlinear optics, polymorphism, surface crystallization
Electronic versions: 

Bibliographical note

EXT="Isomäki, Antti"

Source: Scopus
Source ID: 85054882971

Research output: Contribution to journalArticleScientificpeer-review

Production and Synthetic Modifications of Shikimic Acid

Shikimic acid is a natural product of industrial importance utilized as a precursor of the antiviral Tamiflu. It is nowadays produced in multihundred ton amounts from the extraction of star anise (Illicium verum) or by fermentation processes. Apart from the production of Tamiflu, shikimic acid has gathered particular notoriety as its useful carbon backbone and inherent chirality provide extensive use as a versatile chiral precursor in organic synthesis. This review provides an overview of the main synthetic and microbial methods for production of shikimic acid and highlights selected methods for isolation from available plant sources. Furthermore, we have attempted to demonstrate the synthetic utility of shikimic acid by covering the most important synthetic modifications and related applications, namely, synthesis of Tamiflu and derivatives, synthetic manipulations of the main functional groups, and its use as biorenewable material and in total synthesis. Given its rich chemistry and availability, shikimic acid is undoubtedly a promising platform molecule for further exploration. Therefore, in the end, we outline some challenges and promising future directions.

General information

Publication status: Published
MoE publication type: A2 Review article in a scientific journal
Organisations: Research group: Chemistry & Advanced Materials, Chemistry and Bioengineering, Bulgarian Acad Sci, Bulgarian Academy of Sciences, Inst Organ Chem, Ctr Phytochem, Lab Organ Synth & Stereochem
Contributors: Candeias, N. R., Assoah, B., Simeonov, S. P.
Number of pages: 93
Pages: 10458-10550
Publication date: 24 Oct 2018
Peer-reviewed: Yes

Publication information

Journal: Chemical Reviews
Volume: 118
Issue number: 20
ISSN (Print): 0009-2665
Ratings: 
  • Scopus rating (2018): CiteScore 54.26 SJR 22.157 SNIP 12.162
Original language: English
Keywords: OSELTAMIVIR PHOSPHATE TAMIFLU, DIELS-ALDER REACTION, ESCHERICHIA-COLI STRAIN, CHINESE STAR ANISE, HIGHLY EFFICIENT SYNTHESIS, MARINE NATURAL-PRODUCT, CARBOHYDRATE PHOSPHOTRANSFERASE SYSTEM, INFLUENZA NEURAMINIDASE INHIBITOR, INTERMEDIATES POTENTIALLY USEFUL, ABUNDANT (-)-SHILDMIC ACID
Source: WOS
Source ID: 000448754700006

Research output: Contribution to journalReview ArticleScientificpeer-review

Decane-1,2-diol derivatives as potential antitumor agents for the treatment of glioblastoma

Glioblastoma remains the most common and aggressive type of malignant brain tumor among adults thus, considerable attention has been given to discovery of novel anti-tumor drugs for its treatment. This study reports the synthesis of a series of twelve novel decane-1,2-diol derivatives and evaluation of its anti-tumor activity in mammalian glioblastoma cell lines, U87 and LN229. Starting from decane-1,2-diol, several derivatives were prepared using a diversity oriented synthesis approach through which a small library composed of esters, silyl ethers, sulfonates, sulfites, sulfates, ketals, and phosphonates was built. The decane-1,2-diol ditosylated derivative, DBT, found to have higher cytotoxicity than the standard drug cisplatin, has IC50 value of 52µM in U87 and 270µM in LN229. Migration analysis of U87 cell line treated with the DBT indicated its ability to effectively suppress proliferation during initial hours of treatment and decrease anti-proliferative property over time. Additionally, DBT was assessed for its role in apoptosis, oxidative stress and caspase 3/7 activation in U87. Interestingly, our experiments indicated that its cytotoxicity is independent of Reactive oxygen species induced caspase 3/7 activity. The compound also exhibited caspase independent apoptosis activity in U87. DBT treatment led to G1/S cell cycle arrest and apoptosis induction of glioma cell lines. In addition, we identified 1,533 genes with significant changes at the transcriptional level, in response to DBT. A molecular docking study accounting for the interaction of DBT with NMDA receptor disclosed several hydrogen bonds and charged residue interactions with 17 amino acids, which might be the basis of the DBT cytotoxicity observed. We conclude that this molecule exerts its cytotoxicity via caspase 3/7 independent pathways in glioblastoma cells. Concisely, simple decane-1,2-diol derivatives might serve as scaffolds for the development of effective anti-glioblastoma agents.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Faculty of Biomedical Sciences and Engineering, Chemistry and Bioengineering, Research group: Computational Systems Biology, Research group: Chemistry & Advanced Materials, Research group: Predictive Society and Data Analytics (PSDA), Centre of Advanced Study in Crystallography & Biophysics, University of Madras, Chennai - 600 025.
Contributors: Viswanathan, A., Zhurina, A., Assoah, B., Paakkunainen, A., Musa, A., Kute, D., Saravanan, K. M., Yli-Harja, O., Candeias, N. R., Kandhavelu, M.
Pages: 105-116
Publication date: 15 Oct 2018
Peer-reviewed: Yes
Early online date: 1 Sep 2018

Publication information

Journal: European Journal of Pharmacology
Volume: 837
ISSN (Print): 0014-2999
Ratings: 
  • Scopus rating (2018): CiteScore 3.24 SJR 1.001 SNIP 0.958
Original language: English

Bibliographical note

INT=tut-bmt,"Zhurina, Anastasia"
INT=keb,"Paakkunainen, Aleksi"
INT=tut-bmt,"Kute, Dinesh"

Source: PubMed
Source ID: 30179612

Research output: Contribution to journalArticleScientificpeer-review

Reconfigurable photoactuator through synergistic use of photochemical and photothermal effects

A reconfigurable actuator is a stimuli-responsive structure that can be programmed to adapt different shapes under identical stimulus. Reconfigurable actuators that function without control circuitry and are fueled remotely are in great demand to devise adaptive soft robotic devices. Yet, obtaining fast and reliable reconfiguration remains a grand challenge. Here we report a facile fabrication pathway towards reconfigurability, through synergistic use of photochemical and photothermal responses in light-active liquid crystal polymer networks. We utilize azobenzene photoisomerization to locally control the cis-isomer content and to program the actuator response, while subsequent photothermal stimulus actuates the structure, leading to shape morphing. We demonstrate six different shapes reconfigured from one single actuator under identical illumination conditions, and a light-fueled smart gripper that can be commanded to either grip and release or grip and hold an object after ceasing the illumination. We anticipate this work to enable all-optical control over actuator performance, paving way towards reprogrammable soft micro-robotics.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials
Contributors: Lahikainen, M., Zeng, H., Priimägi, A.
Number of pages: 9
Publication date: 8 Oct 2018
Peer-reviewed: Yes

Publication information

Journal: Nature Communications
Volume: 9
Article number: 4148
ISSN (Print): 2041-1723
Ratings: 
  • Scopus rating (2018): CiteScore 12.19 SJR 5.992 SNIP 2.805
Original language: English

Research output: Contribution to journalArticleScientificpeer-review

Quantification of bio-anode capacitance in bioelectrochemical systems using Electrochemical Impedance Spectroscopy

Understanding the electrochemical properties of bio-anodes is essential to improve performance of bioelectrochemical systems. Electrochemical Impedance Spectroscopy (EIS) is often used to study these properties in detail. Analysis of the EIS response, however, is challenging due to the interfering effect of the large capacitance of typically used graphite and carbon-based electrodes. In this study, we used flat electrodes made of conductive Fluorine-doped Tin Oxide (FTO) as anode, and monitored bio-anode performance. We show that with this configuration, it is possible to accurately separate the distinct contributions to the electrical response of the bio-anodes: charge transfer, biofilm and diffusion resistances, and biofilm capacitance. We observed that the capacitance of the biofilm increased from 2 μF cm−2 to 450 μF cm−2 during biofilm growth, showing a relationship with current and total produced charge. These results suggest that biofilm capacitance is a measure for the amount of active biomass in bioelectrochemical systems. At the end of the experiment, the biofilm was harvested from the FTO electrode and an average yield of 0.55 g COD biomass/mol e was determined.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, Wageningen University and Research Centre, Wetsus, Centre for Sustainable Water Technology, Universitat Jaume I
Contributors: Heijne, A. T., Liu, D., Sulonen, M., Sleutels, T., Fabregat-Santiago, F.
Number of pages: 6
Pages: 533-538
Publication date: 1 Oct 2018
Peer-reviewed: Yes

Publication information

Journal: Journal of Power Sources
Volume: 400
ISSN (Print): 0378-7753
Ratings: 
  • Scopus rating (2018): CiteScore 7.19 SJR 1.947 SNIP 1.433
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, Physical and Theoretical Chemistry, Electrical and Electronic Engineering
Keywords: BES, Bioanode, Biomass yield, Capacitance, Electrochemical Impedance Spectroscopy, MET, Microbial fuel cell
Electronic versions: 
Source: Scopus
Source ID: 85052096235

Research output: Contribution to journalArticleScientificpeer-review

Removal and recovery of uranium(VI) by waste digested activated sludge in fed-batch stirred tank reactor

This study demonstrated the removal and recovery of uranium(VI) in a fed-batch stirred tank reactor (STR) using waste digested activated sludge (WDAS). The batch adsorption experiments showed that WDAS can adsorb 200 (±9.0) mg of uranium(VI) per g of WDAS. The maximum adsorption of uranium(VI) was achieved even at an acidic initial pH of 2.7 which increased to a pH of 4.0 in the equilibrium state. Desorption of uranium(VI) from WDAS was successfully demonstrated from the release of more than 95% of uranium(VI) using both acidic (0.5 M HCl) and alkaline (1.0 M Na2CO3) eluents. Due to the fast kinetics of uranium(VI) adsorption onto WDAS, the fed-batch STR was successfully operated at a mixing time of 15 min. Twelve consecutive uranium(VI) adsorption steps with an average adsorption efficiency of 91.5% required only two desorption steps to elute more than 95% of uranium(VI) from WDAS. Uranium(VI) was shown to interact predominantly with the phosphoryl and carboxyl groups of the WDAS, as revealed by in situ infrared spectroscopy and time-resolved laser-induced fluorescence spectroscopy studies. This study provides a proof-of-concept of the use of fed-batch STR process based on WDAS for the removal and recovery of uranium(VI).

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Helmholtz-Zentrum Dresden-Rossendorf, Ita-Suomen yliopisto
Contributors: Jain, R., Peräniemi, S., Jordan, N., Vogel, M., Weiss, S., Foerstendorf, H., Lakaniemi, A.
Number of pages: 9
Pages: 167-175
Publication date: 1 Oct 2018
Peer-reviewed: Yes

Publication information

Journal: Water Research
Volume: 142
ISSN (Print): 0043-1354
Ratings: 
  • Scopus rating (2018): CiteScore 8.55 SJR 2.721 SNIP 2.426
Original language: English
ASJC Scopus subject areas: Ecological Modelling, Water Science and Technology, Waste Management and Disposal, Pollution
Keywords: Adsorption, Desorption, Infrared spectroscopy, Sludge, STR, Uranium
Source: Scopus
Source ID: 85047810396

Research output: Contribution to journalArticleScientificpeer-review

Electro-concentration for chemical-free nitrogen capture as solid ammonium bicarbonate

Source-separated urine is a promising stream for nutrient capture using electrochemical technologies. It contains the majority of macronutrients present in municipal wastewater in a concentrated, high ionic conductivity liquid and in N:P:K ratios suitable for agricultural application. The purpose of this study was to recover nutrients from urine, and particularly nitrogen as a solid without any chemical addition. Simulated source-separated urine was concentrated using a three-compartment electrochemical system, applying a range of current densities and feed compositions. Electro-concentration into a liquid concentrate reached maximum recovery of 72:61:79% for N:P:K, respectively, from a synthetic feed simulating ureolysed and digested urine, with a specific electrical energy consumption of 47 MJ/kg N and current efficiency of 67% for ammonium. Cooling the concentrate to −18 °C resulted in solid ammonium bicarbonate crystal formation in samples with high ammonium bicarbonate ionic product and high relative ammonium bicarbonate ionic strength. Precipitation started to occur when ammonium bicarbonate ionic product was higher than 2.25 M2 and ammonium bicarbonate accounted for more than 62% of the total ionic strength of the feed. The maximum observed nitrogen recovery into solid ammonium bicarbonate reached 17% using a current density of 100 A m−2. Based on these results, electro-concentration is a promising technology for urine nutrient capture. However, capture as solid ammonium bicarbonate is feasible only if higher recovery efficiencies are achieved by removing competing ions.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, University of Queensland
Contributors: Jermakka, J., Thompson Brewster, E., Ledezma, P., Freguia, S.
Number of pages: 8
Pages: 48-55
Publication date: 12 Sep 2018
Peer-reviewed: Yes
Early online date: 2018

Publication information

Journal: Separation and Purification Technology
Volume: 203
ISSN (Print): 1383-5866
Ratings: 
  • Scopus rating (2018): CiteScore 5.05 SJR 1.158 SNIP 1.458
Original language: English
ASJC Scopus subject areas: Analytical Chemistry, Filtration and Separation
Keywords: Ammonium bicarbonate precipitation, Electro-concentration, Nutrient recovery, Urine
Source: Scopus
Source ID: 85045218335

Research output: Contribution to journalArticleScientificpeer-review

Entangled and colloidally stable microcrystalline cellulose matrices in controlled drug release

Drug release from a new type of matrix material consisting of partially fibrillated microcrystalline cellulose was investigated. A mechanical treatment of novel AaltoCell™ cellulose microcrystals caused partial opening of the nanofibrillary structure of the cellulose particles and entanglement of individual particles led into formation of an elastic network of microcrystalline cellulose. The rheological properties of the stable hydrogel-like materials were characterised by shear rheometry. Model compounds metronidazole and lysozyme were successfully employed in drug release experiments carried out by delignified (bleached) and lignin-containing matrices. The viscosity as well as the lignin-content played a role in the release dynamics of the drugs. Microcrystalline AaltoCell™ was proven as high-performing material for diffusion controlled release of the chosen model compounds and can be seen as a safe and economical alternative for novel matrix materials such as nanocellulose or cellulose derivatives.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Chemistry & Advanced Materials, Chemistry and Bioengineering, Aalto University, University of Helsinki, Centre for Drug Research
Contributors: Dong, Y., Paukkonen, H., Fang, W., Kontturi, E., Laaksonen, T., Laaksonen, P.
Number of pages: 7
Pages: 113-119
Publication date: 5 Sep 2018
Peer-reviewed: Yes

Publication information

Journal: International Journal of Pharmaceutics
Volume: 548
Issue number: 1
ISSN (Print): 0378-5173
Ratings: 
  • Scopus rating (2018): CiteScore 4.35 SJR 1.135 SNIP 1.23
Original language: English
ASJC Scopus subject areas: Pharmaceutical Science
Keywords: Cellulose hydrogel, Controlled release, Diffusion-limited release, Microcrystalline cellulose
Electronic versions: 
URLs: 
Source: Scopus
Source ID: 85049349070

Research output: Contribution to journalArticleScientificpeer-review

Post operation inactivation of acidophilic bioleaching microorganisms using natural chloride-rich mine water

The H2020 BIOMOre project (www.biomore.info, Grant Agreement #642456) tests the feasibility of in situ bioleaching of copper in deep subsurface deposits in the Rudna mine, Poland. Copper is leached using biologically produced ferric iron solution, which is recycled back to the in situ reactor after re-oxidation by iron-oxidizing microorganisms. From a post operational point of view, it is important that the biological processes applied during the operation can be controlled and terminated. Our goal was to determine the possibility to use natural saline mine water for the inactivation of the introduced iron-oxidizing microorganisms remaining in the in situ reactor after completion of the leaching process of the ore block. Aerobic and anaerobic microcosms containing acid-leached (pH 2) sandstone or black shale from the Kupferschiefer in the Rudna mine were further leached with the effluent from a ferric iron generating bioreactor at 30 °C for 10 days to simulate the in situ leaching process. After the removal of the iron solution, residing iron-oxidizing microorganisms were inactivated by filling the microcosms with chloride-rich water (65 g L−1 Cl) originating from the mine. The chloride-rich water irreversibly inactivated the iron-oxidizing microorganisms and showed that the naturally occurring saline water of the mine can be used for long-term post process inactivation of bioleaching microorganisms

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, VTT Technical Research Centre of Finland
Contributors: Bomberg, M., Miettinen, H., Wahlström, M., Kaartinen, T., Ahoranta, S., Lakaniemi, A., Kinnunen, P.
Number of pages: 10
Pages: 236-245
Publication date: 1 Sep 2018
Peer-reviewed: Yes

Publication information

Journal: Hydrometallurgy
Volume: 180
ISSN (Print): 0304-386X
Ratings: 
  • Scopus rating (2018): CiteScore 4 SJR 1.014 SNIP 1.817
Original language: English
ASJC Scopus subject areas: Industrial and Manufacturing Engineering, Metals and Alloys, Materials Chemistry
Keywords: BIOMOre, in situ bioleaching, Inactivation, Iron-oxidizing bacteria, Quantitative PCR
Source: Scopus
Source ID: 85051388591

Research output: Contribution to journalArticleScientificpeer-review

Recent progress in biohydrometallurgy and microbial characterisation

Since the discovery of microbiological metal dissolution, numerous biohydrometallurgical approaches have been developed to use microbially assisted aqueous extractive metallurgy for the recovery of metals from ores, concentrates, and recycled or residual materials. Biohydrometallurgy has helped to alleviate the challenges related to continually declining ore grades by transforming uneconomic ore resources to reserves. Engineering techniques used for biohydrometallurgy span from above ground reactor, vat, pond, heap and dump leaching to underground in situ leaching. Traditionally biohydrometallurgy has been applied to the bioleaching of base metals and uranium from sulfides and the biooxidation of sulfidic refractory gold ores and concentrates before cyanidation. More recently the interest in using bioleaching for oxide ore and waste processing, as well as extracting other commodities such as rare earth elements has been growing. Bioprospecting, adaptation, engineering and storing of microorganisms has increased the availability of suitable biocatalysts for biohydrometallurgical applications. Moreover, the advancement of microbial characterisation methods has increased the understanding of microbial communities and their capabilities in the processes. This paper reviews recent progress in biohydrometallurgy and microbial characterisation.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, CSIRO Land and Water, School of Biomedical Sciences, University of Western Australia, CSIRO Mineral Resources, Murdoch University
Contributors: Kaksonen, A. H., Boxall, N. J., Gumulya, Y., Khaleque, H. N., Morris, C., Bohu, T., Cheng, K. Y., Usher, K. M., Lakaniemi, A.
Number of pages: 19
Pages: 7-25
Publication date: 1 Sep 2018
Peer-reviewed: Yes

Publication information

Journal: Hydrometallurgy
Volume: 180
ISSN (Print): 0304-386X
Ratings: 
  • Scopus rating (2018): CiteScore 4 SJR 1.014 SNIP 1.817
Original language: English
ASJC Scopus subject areas: Industrial and Manufacturing Engineering, Metals and Alloys, Materials Chemistry
Keywords: Biohydrometallurgy, Bioleaching, Biooxidation, Characterisation, Microbiology

Bibliographical note

EXT="Kaksonen, Anna H."

Source: Scopus
Source ID: 85049805480

Research output: Contribution to journalArticleScientificpeer-review

Photoinduced Energy Transfer in ZnCdSeS Quantum Dot-Phthalocyanines Hybrids

In this article, interaction between ZnCdSeS quantum dot (QD) and phthalocyanines with variable linker has been reported. Steady-state and time-resolved spectroscopic investigation reveals that only photoinduced energy transfer occurs from QD to phthalocyanines. To evaluate quantitatively the energy transfer, the Poisson statistics of QD-dye complex formation was used in the analysis of steady-state and time-resolved emission quenching, which allows to estimate the energy transfer rate constant for an ideal one-to-one complex. The measured rate constants are compared to the rates evaluated based on the classic Förster theory, which shows roughly 1 nm discrepancy in the energy transfer distance estimation, or one order in magnitude discrepancy in the transfer rate constants.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Universidad Autónoma de Madrid, Instituto Madrileño de Estudios Avanzados (IMDEA)-Nanociencia, Mersin University
Contributors: Mandal, S., Garcia Iglesias, M., Ince, M., Torres, T., Tkachenko, N. V.
Number of pages: 10
Pages: 10048-10057
Publication date: 31 Aug 2018
Peer-reviewed: Yes

Publication information

Journal: ACS Omega
Volume: 3
Issue number: 8
ISSN (Print): 2470-1343
Ratings: 
  • Scopus rating (2018): CiteScore 2.54 SJR 0.754 SNIP 0.673
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all)
Electronic versions: 
Source: Scopus
Source ID: 85052704543

Research output: Contribution to journalArticleScientificpeer-review

FLIM reveals alternative EV-mediated cellular up-take pathways of paclitaxel

In response to physiological and artificial stimuli, cells generate nano-scale extracellular vesicles (EVs) by encapsulating biomolecules in plasma membrane-derived phospholipid envelopes. These vesicles are released to bodily fluids, hence acting as powerful endogenous mediators in intercellular signaling. EVs provide a compelling alternative for biomarker discovery and targeted drug delivery, but their kinetics and dynamics while interacting with living cells are poorly understood. Here we introduce a novel method, fluorescence lifetime imaging microscopy (FLIM) to investigate these interaction attributes. By FLIM, we show distinct cellular uptake mechanisms of different EV subtypes, exosomes and microvesicles, loaded with anti-cancer agent, paclitaxel. We demonstrate differences in intracellular behavior and drug release profiles of paclitaxel-containing EVs. Exosomes seem to deliver the drug mostly by endocytosis while microvesicles enter the cells by both endocytosis and fusion with cell membrane. This research offers a new real-time method to investigate EV kinetics with living cells, and it is a potential advancement to complement the existing techniques. The findings of this study improve the current knowledge in exploiting EVs as next-generation targeted drug delivery systems.

General information

Publication status: Published
MoE publication type: A2 Review article in a scientific journal
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Faculty of Pharmacy, University of Helsinki, UC Davis, Orion Corporation, Universita degli Studi di Padova, Italy
Contributors: Saari, H., Lisitsyna, E., Rautaniemi, K., Rojalin, T., Niemi, L., Nivaro, O., Laaksonen, T., Yliperttula, M., Vuorimaa-Laukkanen, E.
Number of pages: 11
Pages: 133-143
Publication date: 28 Aug 2018
Peer-reviewed: Yes

Publication information

Journal: Journal of Controlled Release
Volume: 284
ISSN (Print): 0168-3659
Ratings: 
  • Scopus rating (2018): CiteScore 7.82 SJR 2.411 SNIP 1.717
Original language: English
ASJC Scopus subject areas: Pharmaceutical Science
Keywords: Cancer, Drug delivery, Exosomes, Extracellular vesicles, Fluorescence lifetime imaging microscopy, Microvesicles, Paclitaxel, Prostate
Electronic versions: 
Source: Scopus
Source ID: 85048776358

Research output: Contribution to journalReview ArticleScientificpeer-review

Optimization of Fin Arrays Cooled by Forced or Natural Convection

Electronic components must be cooled to maintain their operating temperatures below the specified limits. If the maximum permissible limit of a component is exceeded, its service life decreases considerably. With increasing power densities in recent decades, the use of heat sinks to improve component cooling has become virtually mandatory in many applications. However, designing a heat sink, which optimally compromises its material weight and its heat transfer performance, is a difficult task because the result depends heavily on its geometrical structure and its operating conditions.

In this thesis, a fast way to optimize industrial heat sinks with a fixed set of heat dissipating components is presented. In a typical optimization case, several hundred temperature field evaluations are needed to find the optimal geometry. These evaluations consume a lot of CPU time if done with conventional CFD. The main objective of this thesis is, therefore, to present a new calculation model, which can handle these temperature field evaluations in a much shorter time. In the model, the speedup is obtained by replacing the slow 3D CFD -solution of air velocity and temperature distributions with 1D solutions for the mean values of these distributions, where convective heat transfer and shear stress are calculated from analytical correlations. A complete 3D numerical solution is only performed for the solid temperature field. These modifications make the new model at least a thousand times faster than CFD.

The calculation model is then tested for accuracy in many test cases, where its results are compared to those calculated with CFD and analytical solutions. These comparisons ensure that the model operates with the precision needed for optimization to predict the maximum temperature of the components. This is important because, in optimization, the maximum temperature of the components is the most crucial quantity.

After accuracy testing, the use of the model as part of an efficient multi-objective optimization algorithm is demonstrated in many distinct cases. Instead of just one optimal solution, multiobjective optimization results in a set of best compromise solutions, called the Pareto optimal set, according to the chosen criteria. Usually, the optimization criteria are the maximum temperature of the components and the weight of the material, or the external volume, of the heat sink. A wellperformed optimization can allow a significant reduction of the solid material used. In the heat sink manufacturing industry, the potential for total savings in material, energy, and CO2 emissions is significant as the global market size of thermal management technology is vast.

General information

Publication status: Published
MoE publication type: G5 Doctoral dissertation (article)
Organisations: Chemistry and Bioengineering
Contributors: Lampio, K.
Number of pages: 71
Publication date: 24 Aug 2018

Publication information

Publisher: Tampere University of Technology
ISBN (Print): 978-952-15-4171-1
ISBN (Electronic): 978-952-15-4175-9
Original language: English

Publication series

Name: Tampere University of Technology. Publication
Volume: 1558
ISSN (Print): 1459-2045

Research output: Book/ReportDoctoral thesisCollection of Articles

Methods to design optimum heat sink geometries

This paper gives a short review of recent studies dealing with optimization of conjugated heat transfer of fin arrays. First, some results considering optimal geometries of single fins are presented to give some idea on how fin shape affects heat transfer. The main emphasis is on fin arrays, which can be solved with CFD, but it requires plenty of CPU-time and is thus often rejected in optimization of industrial applications. If the most time consuming phase of the solution, the convective heat transfer, is handled using analytical results and only conduction is solved numerically, we have a fast performing tool for design and optimization process. With this approach, the CPU-time is many orders of magnitude smaller than in the case of pure numerical solution with CFD. The accuracy of the results is checked by comparing them to experimental, and in some simple cases, to numerically calculated results. After testing the accuracy of the model, it is applied using multi-objective optimization to fin arrays cooled by natural and forced convection. The selected optimization algorithm was a multi-objective version of particle swarm optimization (PSO) algorithm, which works well.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Mechanical Engineering and Industrial Systems, Chemistry and Bioengineering, Research group: Bio- and Circular Economy
Contributors: Karvinen, R., Lampio, K.
Number of pages: 8
Pages: 5041-5048
Publication date: 10 Aug 2018

Host publication information

Title of host publication: International Heat Transfer Conference, IHTC-16, August 10-15, 2018, Beijing, China
Article number: IHTC16-23247

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

A new method to optimize natural convection heat sinks

The performance of a heat sink cooled by natural convection is strongly affected by its geometry, because buoyancy creates flow. Our model utilizes analytical results of forced flow and convection, and only conduction in a solid, i.e., the base plate and fins, is solved numerically. Sufficient accuracy for calculating maximum temperatures in practical applications is proved by comparing the results of our model with some simple analytical and computational fluid dynamics (CFD) solutions. An essential advantage of our model is that it cuts down on calculation CPU time by many orders of magnitude compared with CFD. The shorter calculation time makes our model well suited for multi-objective optimization, which is the best choice for improving heat sink geometry, because many geometrical parameters with opposite effects influence the thermal behavior. In multi-objective optimization, optimal locations of components and optimal dimensions of the fin array can be found by simultaneously minimizing the heat sink maximum temperature, size, and mass. This paper presents the principles of the particle swarm optimization (PSO) algorithm and applies it as a basis for optimizing existing heat sinks.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Mechanical Engineering and Industrial Systems
Contributors: Lampio, K., Karvinen, R.
Pages: 2571-2580
Publication date: Aug 2018
Peer-reviewed: Yes

Publication information

Journal: Heat and Mass Transfer/Waerme- und Stoffuebertragung
Volume: 54
Issue number: 8
ISSN (Print): 0947-7411
Ratings: 
  • Scopus rating (2018): CiteScore 1.72 SJR 0.561 SNIP 0.81
Original language: English
ASJC Scopus subject areas: Condensed Matter Physics, Fluid Flow and Transfer Processes
Source: Scopus
Source ID: 85028537040

Research output: Contribution to journalArticleScientificpeer-review

Selenate removal in biofilm systems: Effect of nitrate and sulfate on selenium removal efficiency, biofilm structure and microbial community

BACKGROUND: Selenium (Se) discharged into natural waterbodies can accumulate over time and have negative impacts on the environment. Se-laden wastewater streams can be treated using biological processes. However, the presence of other electron acceptors in wastewater, such as nitrate (NO3 -) and sulfate (SO4 2-), can influence selenate (SeO4 2-) reduction and impact the efficiency of biological treatment systems. RESULTS: SeO4 2- removal by biofilms formed from an anaerobic sludge inoculum was investigated in the presence of NO3 - and SO4 2- using drip flow reactors operated continuously for 10days at pH7.0 and 30°C. The highest total Se (∼60%) and SeO4 2- (∼80%) removal efficiencies were observed when the artificial wastewater contained SO4 2-. A maximum amount of 68μmol Se cm-2 was recovered from the biofilm matrix in SO4 2-+SeO4 2- exposed biofilms and biofilm mass was 2.7-fold increased for biofilms grown in the presence of SO4 2-. When SeO4 2- was the only electron acceptor, biofilms were thin and compact. In the simultaneous presence of NO3 - or SO4 2-, biofilms were thicker (> 0.6mm), less compact and exhibited gas pockets. CONCLUSION: The presence of SO4 2- had a beneficial effect on biofilm growth and the SeO4 2- removal efficiency, while the presence of NO3 - did not have a significant effect on SeO4 2- removal by the biofilms.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Hydraulic and Environmental Engineering (IHE) Inst. for Water Education, Montana State University (MSU), Bhabha Atomic Research Centre, UPEM
Contributors: Tan, L. C., Espinosa-Ortiz, E. J., Nancharaiah, Y. V., van Hullebusch, E. D., Gerlach, R., Lens, P. N.
Pages: 2380-2389
Publication date: Aug 2018
Peer-reviewed: Yes
Early online date: 1 Jan 2018

Publication information

Journal: Journal of Chemical Technology and Biotechnology
Volume: 93
Issue number: 8
ISSN (Print): 0268-2575
Ratings: 
  • Scopus rating (2018): CiteScore 2.88 SJR 0.715 SNIP 0.883
Original language: English
ASJC Scopus subject areas: Biotechnology, Chemical Engineering(all), Renewable Energy, Sustainability and the Environment, Fuel Technology, Waste Management and Disposal, Pollution, Organic Chemistry, Inorganic Chemistry
Keywords: Biofilm, Biofilm characterization, Co-electron acceptors, Nitrate, Selenate, Selenium removal, Sulfate
Source: Scopus
Source ID: 85043713774

Research output: Contribution to journalArticleScientificpeer-review

Design aspects of all atomic layer deposited TiO2–Fe2O3 scaffold-absorber photoanodes for water splitting

Iron and titanium oxides have attracted substantial attention in photoelectrochemical water splitting applications. However, both materials suffer from intrinsic limitations that constrain the final device performance. In order to overcome the limitations of the two materials alone, their combination has been proposed as a solution to the problems. Here we report on the fabrication of an atomic layer deposited (ALD) Fe2O3 coating on porous ALD-TiO2. Our results show that successful implementation requires complete mixing of the TiO2 and Fe2O3 layers via annealing resulting in the formation of a photoactive iron titanium oxide on the surface. Moreover, we found that incomplete mixing leads to crystallization of Fe2O3 to hematite that is detrimental to the photoelectrochemical performance. IPCE and transient photocurrent measurements performed using UV and visible light excitation confirmed that the iron titanium oxide extends the photocurrent generation to the visible range. These measurements were complemented by transient absorption spectroscopy (TAS), which revealed a new band absent in pristine hematite or anatase TiO2 that we assign to charge transfer within the structure. Taken together, these results provide design guidelines to be considered when aiming to combine TiO2 and Fe2O3 for photoelectrochemical applications.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Research group: Surface Science, Photonics, Materials Science, Research group: Plastics and Elastomer Technology
Contributors: Hiltunen, A., Ruoko, T., Iivonen, T., Lahtonen, K., Ali-Löytty, H., Sarlin, E., Valden, M., Leskelä, M., Tkachenko, N.
Pages: 2124-2130
Publication date: 31 Jul 2018
Peer-reviewed: Yes

Publication information

Journal: Sustainable Energy & Fuels
Volume: 2
Issue number: 9
ISSN (Print): 2398-4902
Ratings: 
  • Scopus rating (2018): CiteScore 4.94 SNIP 0.841
Original language: English
ASJC Scopus subject areas: Electrochemistry, Renewable Energy, Sustainability and the Environment, Surfaces, Coatings and Films
Keywords: Water splitting, Atomic layer deposition (ALD), Titanium dioxide, Hematite, Cellulose, Template

Research output: Contribution to journalArticleScientificpeer-review

Comparison of electron injection and recombination on TiO2 nanoparticles and ZnO nanorods photosensitized by phthalocyanine

Titanium dioxide (TiO2) and zinc oxide (ZnO) semiconductors have similar band gap positions but TiO2 performs better as an anode material in dye-sensitized solar cell applications. We compared two electrodes made of TiO2 nanoparticles and ZnO nanorods sensitized by an aggregation-protected phthalocyanine derivative using ultrafast transient absorption spectroscopy. In agreement with previous studies, the primary electron injection is two times faster on TiO2, but contrary to the previous results the charge recombination is slower on ZnO. The latter could be due to morphology differences and the ability of the injected electrons to travel much further from the sensitizer cation in ZnO nanorods.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Universidad Autónoma de Madrid, Mersin University, Instituto Madrileño de Estudios Avanzados (IMDEA)-Nanociencia
Contributors: Virkki, K., Tervola, E., Ince, M., Torres, T., Tkachenko, N. V.
Publication date: 11 Jul 2018
Peer-reviewed: Yes

Publication information

Journal: Royal Society Open Science
Volume: 5
Issue number: 7
Article number: 180323
ISSN (Print): 2054-5703
Ratings: 
  • Scopus rating (2018): CiteScore 2.71 SJR 1.131 SNIP 1.058
Original language: English
ASJC Scopus subject areas: General
Keywords: Photo-induced electron transfer, Phthalocyanine, Semiconductor–organic interface, TiO nanoparticles, ZnO nanorods
Electronic versions: 
Source: Scopus
Source ID: 85050034317

Research output: Contribution to journalArticleScientificpeer-review

Halogen-bond driven self-assembly of triangular macrocycles

2-Iodoethynylpyridine and 2-iodoethynyl-1-methyl-imidazole self-assemble under halogen-bonding control into discrete macrocycles, viz. supramolecular triangles.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials
Contributors: Szell, P. M. J., Siiskonen, A., Catalano, L., Cavallo, G., Terraneo, G., Priimägi, A., Bryce, D. L., Metrangolo, P.
Number of pages: 5
Pages: 10467-10471
Publication date: 7 Jul 2018
Peer-reviewed: Yes

Publication information

Journal: New Journal of Chemistry
Volume: 42
Issue number: 13
ISSN (Print): 1144-0546
Ratings: 
  • Scopus rating (2018): CiteScore 3.09 SJR 0.716 SNIP 0.724
Original language: English
Source: Bibtex
Source ID: urn:ffbda8958063fdfcff5c170b8d5cde7c

Research output: Contribution to journalArticleScientificpeer-review

Metabolic pairing of aerobic and anaerobic production in a one-pot batch cultivation

Background: The versatility of microbial metabolic pathways enables their utilization in vast number of applications. However, the electron and carbon recovery rates, essentially constrained by limitations of cell energetics, are often too low in terms of process feasibility. Cocultivation of divergent microbial species in a single process broadens the metabolic landscape, and thus, the possibilities for more complete carbon and energy utilization. Results: In this study, we integrated the metabolisms of two bacteria, an obligate anaerobe Clostridium butyricum and an obligate aerobe Acinetobacter baylyi ADP1. In the process, a glucose-negative mutant of A. baylyi ADP1 first deoxidized the culture allowing C. butyricum to grow and produce hydrogen from glucose. In the next phase, ADP1 produced long chain alkyl esters (wax esters) utilizing the by-products of C. butyricum, namely acetate and butyrate. The coculture produced 24.5 ± 0.8 mmol/l hydrogen (1.7 ± 0.1 mol/mol glucose) and 28 mg/l wax esters (10.8 mg/g glucose). Conclusions: The cocultivation of strictly anaerobic and aerobic bacteria allowed the production of both hydrogen gas and long-chain alkyl esters in a simple one-pot batch process. The study demonstrates the potential of 'metabolic pairing' using designed microbial consortia for more optimal electron and carbon recovery.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering
Contributors: Salmela, M., Lehtinen, T., Efimova, E., Santala, S., Mangayil, R.
Publication date: 3 Jul 2018
Peer-reviewed: Yes

Publication information

Journal: Biotechnology for Biofuels
Volume: 11
Issue number: 1
Article number: 187
ISSN (Print): 1754-6834
Ratings: 
  • Scopus rating (2018): CiteScore 5.84 SJR 1.762 SNIP 1.451
Original language: English
ASJC Scopus subject areas: Biotechnology, Applied Microbiology and Biotechnology, Renewable Energy, Sustainability and the Environment, Energy(all), Management, Monitoring, Policy and Law
Keywords: Hydrogen production, Integrated metabolism, Metabolic pairing, Synthetic microbial consortia, Wax esters
Electronic versions: 
Source: Scopus
Source ID: 85049884043

Research output: Contribution to journalArticleScientificpeer-review

Pectin and Mucin Enhance the Bioadhesion of Drug Loaded Nanofibrillated Cellulose Films

Purpose: Bioadhesion is an important property of biological membranes, that can be utilized in pharmaceutical and biomedical applications. In this study, we have fabricated mucoadhesive drug releasing films with bio-based, non-toxic and biodegradable polymers that do not require chemical modifications. Methods: Nanofibrillar cellulose and anionic type nanofibrillar cellulose were used as film forming materials with known mucoadhesive components mucin, pectin and chitosan as functional bioadhesion enhancers. Different polymer combinations were investigated to study the adhesiveness, solid state characteristics, film morphology, swelling, mechanical properties, drug release with the model compound metronidazole and in vitro cytotoxicity using TR146 cells to model buccal epithelium. Results: SEM revealed lamellar structures within the films, which had a thickness ranging 40–240 μm depending on the film polymer composition. All bioadhesive components were non-toxic and showed high adhesiveness. Rapid drug release was observed, as 60–80% of the total amount of metronidazole was released in 30 min depending on the film formulation. Conclusions: The liquid molding used was a straightforward and simple method to produce drug releasing highly mucoadhesive films, which could be utilized in treating local oral diseases, such as periodontitis. All materials used were natural biodegradable polymers from renewable sources, which are generally regarded as safe.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Aalto University, Universita degli Studi di Padova, Italy, University of Helsinki, University of Helsinki
Contributors: Laurén, P., Paukkonen, H., Lipiäinen, T., Dong, Y., Oksanen, T., Räikkönen, H., Ehlers, H., Laaksonen, P., Yliperttula, M., Laaksonen, T.
Publication date: 1 Jul 2018
Peer-reviewed: Yes

Publication information

Journal: Pharmaceutical Research
Volume: 35
Issue number: 7
Article number: 145
ISSN (Print): 0724-8741
Ratings: 
  • Scopus rating (2018): CiteScore 3.89 SJR 1.093 SNIP 1.108
Original language: English
ASJC Scopus subject areas: Biotechnology, Molecular Medicine, Pharmacology, Pharmaceutical Science, Organic Chemistry, Pharmacology (medical)
Keywords: bioadhesion, drug release, mucoadhesion, nanofibrillar cellulose, TR146
Electronic versions: 
URLs: 
Source: Scopus
Source ID: 85047448577

Research output: Contribution to journalArticleScientificpeer-review

Multiexciton Dynamics Depending on Intramolecular Orientations in Pentacene Dimers: Recombination and Dissociation of Correlated Triplet Pairs

Pentacene dimers bridged by a phenylene at ortho and meta positions [denoted as o-(Pc)2 and m-(Pc)2] were synthesized to examine intramolecular orientation-dependent multiexciton dynamics, especially focusing on singlet fission (SF) and recombination from correlated triplet pairs [(TT)]. Absorption and electrochemical measurements indicated strong intramolecular couplings of o-(Pc)2 relative to m-(Pc)2. Femtosecond and nanosecond TA measurements successfully demonstrated efficient SF in both dimers. In contrast, the dissociation process from the (TT) to the individual triplets [(2 × T)] was clearly observed in m-(Pc)2, which is in sharp contrast to a major recombination process in o-(Pc)2. Time-resolved electron spin resonance (TR-ESR) measurements demonstrated that the recombination and dissociation proceed from the quintet state of 5(TT) in m-(Pc)2. The rate constant of the SF was 2 orders of magnitude greater in o-(Pc)2 than that in m-(Pc)2 and was rationalized by enhanced electronic coupling between adjacent HOMOs of the Pc units.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials
Contributors: Sakai, H., Inaya, R., Nagashima, H., Nakamura, S., Kobori, Y., Tkachenko, N. V., Hasobe, T.
Number of pages: 7
Pages: 3354-3360
Publication date: 21 Jun 2018
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry Letters
Volume: 9
Issue number: 12
ISSN (Print): 1948-7185
Ratings: 
  • Scopus rating (2018): CiteScore 7.91 SJR 3.618 SNIP 1.476
Original language: English
Source: PubMed
Source ID: 29847939

Research output: Contribution to journalArticleScientificpeer-review

Light-Activated Antimicrobial Materials Based on Perylene Imides and Phthalocyanines

In the era of globalization, the spread of infectious diseases is a serious concern. The emergence of drug resistant bacteria and healthcare associated infections in particular, poses a great danger to human health. Self-disinfecting surfaces may play a significant role in controlling the spread of pathogenic diseases. Photodynamic antimicrobial chemotherapy (PACT) can be a very efficient way of inactivation of drug resistant bacteria and biofilms. However, making a self-disinfecting surface based on PACT principles requires novel photosensitizers, which can efficiently generate reactive oxygen species, and are stable and accessible. In this thesis, attempts are undertaken to synthesize novel photosensitizers based on peryleneimides and phthalocyanines. We propose a novel efficient method for the direct and regioselective amination of peryleneimides. The substitution occurs with high yields exclusively at 1,6- and 7,12-positions of the bay region of perylenediimide and perylenemonoimide diester. We also report the synthesis of novel cationic peryleneimides, which can be potentially used as photosensitizers in PACT. Phthalocyanines are known to be efficient photosensitizers. In this thesis we present the synthesis of novel pyridinyl-substituted phthalocyanine and its tetracationic derivatives. As a unique synthetic approach, pyridinyl groups are connected to α-phthalo positions of the macrocycle via direct C-C bonds. Prototype self-disinfecting materials are prepared by impregnating filter paper with the synthesized dyes. Binding of the dyes occurs via electrostatic interactions and does not require any special chemical modification. A fast and simple setup for the evaluation of antimicrobial efficacies of dyed papers is proposed. The setup employs bioluminescent bacteria and allows for a fast screening of a large number of dyes. According to the screening results, tetracationic phthalocyanines are the most efficient antimicrobial photosensitizers. The antimicrobial efficacies of phthalocyanine derivatives are evaluated quantitatively with the help of colony forming unit (CFU) counting method. The papers impregnated with as little as 80 mg/m2 of cationic zinc phthalocyanine exhibit 2.7 and 3.4 log reduction in CFU against Escherichia coli (E. coli) and Acinetobacter baylyi (A. baylyi), respectively after illumination with the light intensity 18 mW/cm2 in a solar simulator. Similar antimicrobial efficacies are achieved under illumination with consumer light emitting diode (LED) lights. Phthalocyanine-impregnated papers show very good stability. Incubation of the dye-impregnated papers in phosphatebuffered saline demonstrates superior binding ability of phthalocyanine, with basically no detectable leaching of the dye. Photostability of the dyed paper is also high. Continuous illumination with 42 mW/cm2 LED light for 64 h decreases the absorptance of dyed papers only by 10%.

General information

Publication status: Published
MoE publication type: G5 Doctoral dissertation (article)
Organisations: Chemistry and Bioengineering
Contributors: George, L.
Number of pages: 92
Publication date: 6 Jun 2018

Publication information

Publisher: Tampere University of Technology
ISBN (Print): 978-952-15-4156-8
ISBN (Electronic): 978-952-15-4159-9
Original language: English

Publication series

Name: Tampere University of Technology. Publication
Volume: 1554
ISSN (Print): 1459-2045

Research output: Book/ReportDoctoral thesisCollection of Articles

Effects of wastewater constituents and operational conditions on the composition and dynamics of anodic microbial communities in bioelectrochemical systems

Over the last decade, there has been an ever-growing interest in bioelectrochemical systems (BES) as a sustainable technology enabling simultaneous wastewater treatment and biological production of, e.g. electricity, hydrogen, and further commodities. A key component of any BES degrading organic matter is the anode where electric current is biologically generated from the oxidation of organic compounds. The performance of BES depends on the interactions of the anodic microbial communities. To optimize the operational parameters and process design of BES a better comprehension of the microbial community dynamics and interactions at the anode is required. This paper reviews the abundance of different microorganisms in anodic biofilms and discusses their roles and possible side reactions with respect to their implications on the performance of BES utilizing wastewaters. The most important operational parameters affecting anodic microbial communities grown with wastewaters are highlighted and guidelines for controlling the composition of microbial communities are given.

General information

Publication status: Published
MoE publication type: A2 Review article in a scientific journal
Organisations: Chemistry and Bioengineering, Laboratory for MEMS Applications, Universitat Freiburg im Breisgau, Karlsruhe Institute of Technology, Insitute for Technical Physics, Germany, University of Bremen
Contributors: Kokko, M., Epple, S., Gescher, J., Kerzenmacher, S.
Number of pages: 14
Pages: 376-389
Publication date: 1 Jun 2018
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 258
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2018): CiteScore 7.08 SJR 2.157 SNIP 1.824
Original language: English
ASJC Scopus subject areas: Bioengineering, Environmental Engineering, Renewable Energy, Sustainability and the Environment, Waste Management and Disposal
Keywords: Bioelectrochemical system, Exoelectrogen, Microbial community, Wastewater
Source: Scopus
Source ID: 85043472557

Research output: Contribution to journalReview ArticleScientificpeer-review

Lewis Base Catalyzed Intramolecular Reduction of Salicylaldehydes by Pinacol‐Derived Chlorohydrosilane

A newly developed stable chlorohydrosilane derived from pinacol is herein described. This was successfully used in the reduction of salicylaldehydes in reasonable to excellent yields (51–97 %). The ability of the hydrosilane to react as a reducing agent is increased upon the in situ formation of a trialkoxyhydrosilane and activation with a Lewis base, as further indicated by density functional theory studies. 1,3‐Dimethyl‐3,4,5,6‐tetrahydro‐2(1H)‐pyrimidinone (DMPU) was identified to be a suitable catalyst for this metal‐free reduction, promoting the regio‐ and chemoselective reduction of aldehydes in ortho‐position to phenols, despite the presence of vicinal ketones. The performance of pinacol‐derived chlorohydrosilane in the reduction of salicylaldehydes was further observed to be superior to that of well‐established commercially available chlorohydrosilanes.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Inst Super Tecn, Instituto Superior Tecnico, Universidade de Lisboa, CQFM, Univ Jyvaskyla, University of Jyvaskyla, Dept Chem, Nanosci Ctr
Contributors: Assoah, B., Vale, J. R., Kalenius, E., Veiros, L., Rafael Candeias, N.
Pages: 2910-2917
Publication date: 1 Jun 2018
Peer-reviewed: Yes

Publication information

Journal: European Journal of Organic Chemistry
Volume: 2018
Issue number: 23
ISSN (Print): 1434-193X
Ratings: 
  • Scopus rating (2018): CiteScore 2.81 SJR 0.987 SNIP 0.626
Original language: English

Research output: Contribution to journalArticleScientificpeer-review

Photo-antimicrobial efficacy of zinc complexes of porphyrin and phthalocyanine activated by inexpensive consumer LED lamp

The properties and antimicrobial efficacies of zinc complexes of tetrakis(N-methylpyridinium-4-yl) tetraiodide porphyrin and tetrakis(N-methylpyridinium-4-yl) tetraiodide phthalocyanine impregnated to paper were evaluated. Photo-inactivation of microbes using inexpensive consumer light-emitting diode lamp was assessed on surface of dyed papers. Antimicrobial experiments of phthalocyanine-dyed paper by live cell assessment through colony forming units counting demonstrated 3.72 and 4.01 log reduction against Escherichia coli (E. coli) and Acinetobacter baylyi (A. baylyi) respectively after 1 h of illumination with 35 mW/cm2 light. The porphyrin-dyed paper exhibited 1.66 and 2.01 log reduction in colony forming units against E. coli and A. baylyi respectively after 1 h exposure with 4 mW/cm2 light. Both dyed papers were photo-stable after 64 h of continuous exposure with 42 mW/cm2 light, while phthalocyanine-dyed paper exhibited superior leaching stability in phosphate-buffered saline.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Research group: Bio- and Circular Economy
Contributors: George, L., Hiltunen, A., Santala, V., Efimov, A.
Number of pages: 7
Pages: 94-100
Publication date: 1 Jun 2018
Peer-reviewed: Yes

Publication information

Journal: Journal of Inorganic Biochemistry
Volume: 183
ISSN (Print): 0162-0134
Ratings: 
  • Scopus rating (2018): CiteScore 3.16 SJR 0.655 SNIP 0.895
Original language: English
ASJC Scopus subject areas: Biochemistry, Inorganic Chemistry
Source: Scopus
Source ID: 85044575449

Research output: Contribution to journalArticleScientificpeer-review

Effect of Co-Adsorbate and Hole Transporting Layer on the Photoinduced Charge Separation at the TiO2-Phthalocyanine Interface

Understanding the primary processes of charge separation (CS) in solid-state dye-sensitized solar cells (DSSCs) and, in particular, analysis of the efficiency losses during these primary photoreactions is essential for designing new and efficient photosensitizers. Phthalocyanines (Pcs) are potentially interesting sensitizers having absorption in the red side of the optical spectrum and known to be efficient electron donors. However, the efficiencies of Pc-sensitized DSSCs are lower than that of the best DSSCs, which is commonly attributed to the aggregation tendency of Pcs. In this study, we employ ultrafast spectroscopy to discover why and how much does the aggregation affect the efficiency. The samples were prepared on a standard fluorine-doped tin oxide (FTO) substrates covered by a porous layer of TiO2 nanoparticles, functionalized by a Pc sensitizer and filled by a hole transporting material (Spiro-MeOTAD). The study demonstrates that the aggregation can be suppressed gradually by using co-adsorbates, such as chenodeoxycholic acid (CDCA) and oleic acid, but rather high concentrations of co-adsorbate is required. Gradually, a few times improvement of quantum efficiency was observed at sensitizer/co-adsorbate ratio Pc/CDCA = 1:10 and higher. The time-resolved spectroscopy studies were complemented by standard photocurrent measurements of the same sample structures, which also confirmed gradual increase in photon-to-current conversion efficiency on mixing Pc with CDCA.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Universidad Autónoma de Madrid, Instituto Madrileño de Estudios Avanzados (IMDEA)-Nanociencia, Departamento de Química Orgánica
Contributors: Virkki, K., Tervola, E., Medel, M., Torres, T., Tkachenko, N. V.
Number of pages: 12
Pages: 4947-4958
Publication date: 31 May 2018
Peer-reviewed: Yes

Publication information

Journal: ACS Omega
Volume: 3
Issue number: 5
ISSN (Print): 2470-1343
Ratings: 
  • Scopus rating (2018): CiteScore 2.54 SJR 0.754 SNIP 0.673
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all)
Source: Scopus
Source ID: 85046661219

Research output: Contribution to journalArticleScientificpeer-review

Mesophilic and thermophilic biohydrogen and bioelectricity production from real and synthetic wastewaters

In the last century, fossil fuels have been intensively used for energy production causing a dramatic increase of CO2 level in the atmosphere and the related environmental issues, such as global warming and ozone layer depletion. In 2015, the increased awareness about climate change led to the signature of the Paris agreement, in which 195 countries committed to cut off their greenhouse gases emission by 40% (compared to emissions in 1990) by 2030. The achievement of such an ambitious target is strictly linked to a gradual switch from fossil fuels to sustainable and renewable sources for energy production. This is driving many industries producing organic and inorganic waste towards a biorefinery concept, in which side streams, wastes and wastewaters are seen as a potential feedstocks for biofuel and/or biochemical production.

Dark fermentation and microbial fuel cells (MFCs) are two emerging technologies for biological conversion of the chemical energy of organic compounds into hydrogen (H2) and electricity, respectively. Although these technologies can potentially replace fossil fuels for energy production, their establishment is hindered by their low energy output. Due to kinetic and thermodynamic advantages, high temperature can be the key for increasing both dark fermentative H2 production and electricity production in MFCs. Therefore, this thesis focuses on delineating how temperature influences biological production of H2 and electricity from organic carbon-containing wastewaters.

Start-up and selection of a suitable microbial community is a crucial phase in dark fermentation. Two heat-treated inocula (fresh and digested activated sludge) were compared, in four consecutive batch cycles, for H2 production from xylose at 37, 55 and 70 °C. At both 37 and 55 °C, a higher H2 yield was achieved by the fresh than the digested activated sludge, whereas a very low H2 yield was obtained by both inocula at 70 °C. Then, four different inoculum pretreatments (acidic, alkaline, heat and freezing shocks) were evaluated, in a single-stage batch experiment, for creating an efficient mesophilic (37 °C) and thermophilic (55 °C) H2 producing community. Acidic and alkaline shocks selected known H2 producing microorganisms belonging to Clostridiaceae at the expenses of lactate producing bacteria, resulting in the highest H2 yield at 37 and 55 °C, respectively. Although a heat shock resulted in a low H2 yield in a single batch, H2 production by the heat-treated fresh activated sludge was shown to increase in the experiment with four consecutive batch cycles. This suggests that H2 producing microbial communities may develop in the long-term as long as culture conditions are optimized for growth of H2 producers.

Heat-treated fresh activated sludge was selected as inoculum for continuous H2 production from a xylose-containing synthetic wastewater in a mesophilic (37 °C) and a thermophilic (55-70 °C, increased stepwise) fluidized bed reactor (FBR). A higher H2 yield was obtained in the thermophilic than in the mesophilic FBR. Furthermore, H2 production at 70 °C, which failed in the earlier batch study, was successful in the FBR, with a stable yield of 1.2 mol H2 mol-1 xyloseadded, by adapting the microbial community from 55 °C to 70 °C stepwise at 5 °C intervals. Operation temperature of 70 °C was also found optimal for H2 production from thermomechanical pulping (TMP) wastewater in a temperature gradient incubator assay, as batch cultivation at 70 °C enriched the H2 producing Thermoanaerobacterium sp. and repressed homoacetogenic microorganisms.

A detailed knowledge of microbial communities, and particularly the active subpopulation, is crucial in order to adjust the conditions to favor the growth of exoelectrogenic microorganisms in MFCs. A RNA approach was used to study the structure and role of the anode-attached, membrane-attached and planktonic microbial communities in a mesophilic (37 °C) and a thermophilic (55 °C) two-chamber, xylose-fed MFC. An anodeattached community dominated by Geobacteraceae sustained electricity production at 37 °C, whereas the establishment of methanogenic and H2 oxidizing microorganisms resulted in a low electricity production at 55 °C. However, the development of a thermophilic exoelectrogenic community can be promoted by applying a start-up strategy which includes imposing a negative potential to the anode and chemical inhibition of methanogens. At both 37 and 55 °C, aerobic membrane-attached microorganisms were likely involved in consuming the oxygen diffusing from the cathodic to the anodic chamber, thus favoring the exoelectrogenic microorganisms, which are strictly anaerobic, but competing with them for the substrate. A mesophilic exoelectrogenic community was also shown to produce electricity from TMP wastewater in an upflow MFC operated at 37 °C.

In conclusion, a higher and more stable H2 yield can be achieved in thermophilic rather than mesophilic dark fermentation. Dark fermentation at 70 °C is particularly suitable for treatment of TMP wastewater as it is released at high temperature (50-80 °C) and could be treated on site with minimal energy requirement for heating the bioreactor. TMP wastewater can be also used as substrate for electricity production in mesophilic MFCs. Electricity production in thermophilic MFCs is feasible, but enrichment of thermophilic exoelectrogenic microorganisms may require a long start-up period with optimized conditions. The detailed RNA-level microbial community analysis performed in this study may help in selecting a start-up and operation strategy to optimize electricity production.

General information

Publication status: Published
MoE publication type: G5 Doctoral dissertation (article)
Organisations: Chemistry and Bioengineering
Contributors: Dessi, P.
Number of pages: 89
Publication date: 23 May 2018

Publication information

Publisher: Université Paris-Est
Original language: English
Electronic versions: 

Research output: Book/ReportDoctoral thesisCollection of Articles

Inoculum pretreatment differentially affects the active microbial community performing mesophilic and thermophilic dark fermentation of xylose

The influence of different inoculum pretreatments (pH and temperature shocks) on mesophilic (37 °C) and thermophilic (55 °C) dark fermentative H2 production from xylose (50 mM) and, for the first time, on the composition of the active microbial community was evaluated. At 37 °C, an acidic shock (pH 3, 24 h) resulted in the highest yield of 0.8 mol H2 mol−1 xylose. The H2 and butyrate yield correlated with the relative abundance of Clostridiaceae in the mesophilic active microbial community, whereas Lactobacillaceae were the most abundant non-hydrogenic competitors according to RNA-based analysis. At 55 °C, Clostridium and Thermoanaerobacterium were linked to H2 production, but only an alkaline shock (pH 10, 24 h) repressed lactate production, resulting in the highest yield of 1.2 mol H2 mol−1 xylose. This study showed that pretreatments differentially affect the structure and productivity of the active mesophilic and thermophilic microbial community developed from an inoculum.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Natl. University of Ireland, Galway, ENEA/CREATE/Università Degli Studi Napoli Federico II, University of Cassino and Southern Lazio, Institute for Water Education, UNESCO–IHE
Contributors: Dessì, P., Porca, E., Frunzo, L., Lakaniemi, A., Collins, G., Esposito, G., Lens, P. N.
Pages: 9233-9245
Publication date: 10 May 2018
Peer-reviewed: Yes
Early online date: 1 Jan 2018

Publication information

Journal: International Journal of Hydrogen Energy
Volume: 43
Issue number: 19
ISSN (Print): 0360-3199
Ratings: 
  • Scopus rating (2018): CiteScore 4.16 SJR 1.1 SNIP 1.128
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Fuel Technology, Condensed Matter Physics, Energy Engineering and Power Technology
Keywords: Biohydrogen, Clostridium, Lactobacillus, MiSeq, pH shock, Temperature shock
Source: Scopus
Source ID: 85045538153

Research output: Contribution to journalArticleScientificpeer-review

Crystallization Kinetics of an Amorphous Pharmaceutical Compound Using Fluorescence-Lifetime-Imaging Microscopy

Pharmaceutical scientists are increasingly interested in amorphous drug formulations especially because of their higher dissolution rates. Consequently, the thorough characterization and analysis of these formulations are becoming more and more important for the pharmaceutical industry. Here, fluorescence-lifetime-imaging microscopy (FLIM) was used to monitor the crystallization of an amorphous pharmaceutical compound, indomethacin. Initially, we identified different solid indomethacin forms, amorphous and γ- and α-crystalline, on the basis of their time-resolved fluorescence. All of the studied indomethacin forms showed biexponential decays with characteristic fluorescence lifetimes and amplitudes. Using this information, the crystallization of amorphous indomethacin upon storage in 60 °C was monitored for 10 days with FLIM. The progress of crystallization was detected as lifetime changes both in the FLIM images and in the fluorescence-decay curves extracted from the images. The fluorescence-lifetime amplitudes were used for quantitative analysis of the crystallization process. We also demonstrated that the fluorescence-lifetime distribution of the sample changed during crystallization, and when the sample was not moved between measuring times, the lifetime distribution could also be used for the analysis of the reaction kinetics. Our results clearly show that FLIM is a sensitive and nondestructive method for monitoring solid-state transformations on the surfaces of fluorescent samples.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials
Contributors: Rautaniemi, K., Vuorimaa-Laukkanen, E., Strachan, C. J., Laaksonen, T.
Number of pages: 8
Pages: 1964-1971
Publication date: 7 May 2018
Peer-reviewed: Yes

Publication information

Journal: Molecular Pharmaceutics
Volume: 15
Issue number: 5
ISSN (Print): 1543-8384
Ratings: 
  • Scopus rating (2018): CiteScore 4.7 SJR 1.402 SNIP 1.165
Original language: English
ASJC Scopus subject areas: Molecular Medicine, Pharmaceutical Science, Drug Discovery
Keywords: amorphous materials, crystal growth, fluorescence, fluorescence lifetime, kinetics
Electronic versions: 
Source: Scopus
Source ID: 85046674658

Research output: Contribution to journalArticleScientificpeer-review

Investigating the kinetics and biofuel properties of Alstonia congensis and Ceiba pentandra via torrefaction

Alstonia congensis (Ahun) and Ceiba pentandra (Araba) were chosen as representations of tropical wood in this study. The use of untreated wood for energy recovery could lead to a high loss in efficiency. One way of circumventing this in a developing country such as Nigeria is by exposing the fuel materials to a pre-treatment, such as torrefaction, prior to deployment. Attempts were made to improve the combustion properties of these resources and also to investigate their torrefaction kinetics. Derivations of kinetic parameters using Coats-Redfern method were discontinued due to inconsistent results. A non-linear regression method was then employed and the results compared to the average value obtained by the FWO method, which was considered more viable than the Coats-Redfern method. The kinetic parameters (Ea,A and n) derived by the regression method are 134.45 kJ/mol, 1.83E+13 min−1 and 2.15, respectively, for Araba and 143.38 kJ/mol, 1.90E+10 min−1 and 2.28, respectively, for Ahun. The thermal behaviour of the samples showed that a lower mass yield resulted in a lower energy yield, while the heating values increased with the temperature of torrefaction. The results obtained in this study affirm the possibility of obtaining an optimum conversion of these resources for energy recovery.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, University of Borås, Laboratory of Chemistry and Bioengineering
Contributors: Oluoti, K., Doddapaneni, T. R. K., Richards, T.
Number of pages: 8
Pages: 134-141
Publication date: 1 May 2018
Peer-reviewed: Yes

Publication information

Journal: Energy
Volume: 150
ISSN (Print): 0360-5442
Ratings: 
  • Scopus rating (2018): CiteScore 6.2 SJR 2.048 SNIP 1.822
Original language: English
ASJC Scopus subject areas: Civil and Structural Engineering, Building and Construction, Pollution, Energy(all), Mechanical Engineering, Industrial and Manufacturing Engineering, Electrical and Electronic Engineering
Keywords: Alstonia congensis, Ceiba pentandra, Energy densification, Kinetic parameters, Mini-grid, Torrefaction
Source: Scopus
Source ID: 85042679330

Research output: Contribution to journalArticleScientificpeer-review

Free amino acids and 5′-nucleotides in Finnish forest mushrooms

Edible mushrooms are valued because of their umami taste and good nutritional values. Free amino acids, 5′-nucleotides and nucleosides were analyzed from four Nordic forest mushroom species (Lactarius camphoratus, Boletus edulis, Cantharellus cibarius, Craterellus tubaeformis) using high precision liquid chromatography analysis. To our knowledge, these taste components were studied for the first time from Craterellus tubaeformis and Lactarius camphoratus. The focus was on the umami amino acids and 5′-nucleotides. The free amino acid and 5′-nucleotide/nucleoside contents of studied species differed from each other. In all studied samples, umami amino acids were among five major free amino acids. The highest concentration of umami amino acids was on L. camphoratus whereas B. edulis had the highest content of sweet amino acids and C. cibarius had the highest content of bitter amino acids. The content of umami enhancing 5′-nucleotides were low in all studied species.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Turun Yliopisto/Turun Biomateriaalikeskus
Contributors: Manninen, H., Rotola-Pukkila, M., Aisala, H., Hopia, A., Laaksonen, T.
Number of pages: 6
Pages: 23-28
Publication date: May 2018
Peer-reviewed: Yes
Early online date: 7 Dec 2017

Publication information

Journal: Food Chemistry
Volume: 247
ISSN (Print): 0308-8146
Ratings: 
  • Scopus rating (2018): CiteScore 5.8 SJR 1.768 SNIP 2.17
Original language: English
ASJC Scopus subject areas: Analytical Chemistry, Food Science
Keywords: 5′-Nucleotides, Amino acids, Mushrooms, Umami
URLs: 
Source: Scopus
Source ID: 85037999138

Research output: Contribution to journalArticleScientificpeer-review

Anaerobic digestion of 30−100-year-old boreal lake sedimented fibre from the pulp industry: Extrapolating methane production potential to a practical scale

Since the 1980s, the pulp and paper industry in Finland has resulted in the accumulation of fibres in lake sediments. One such site in Lake Näsijärvi contains approximately 1.5 million m3 sedimented fibres. In this study, the methane production potential of the sedimented fibres (on average 13% total solids (TS)) was determined in batch assays. Furthermore, the methane production from solid (on average 20% TS) and liquid fractions of sedimented fibres after solid-liquid separation was studied. The sedimented fibres resulted in fast methane production and high methane yields of 250 ± 80 L CH4/kg volatile solids (VS). The main part (ca. 90%) of the methane potential was obtained from the solid fraction of the sedimented fibres. In addition, the VS removal from the total and solid sedimented fibres was high, 61–65% and 63–78%, respectively. The liquid fraction also contained a large amount of organics (on average 8.8 g COD/L), treatment of which also has to be considered. The estimations of the methane production potentials in the case area showed potential up to 40 million m3 of methane from sedimented fibres.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering
Contributors: Kokko, M., Koskue, V., Rintala, J.
Number of pages: 9
Pages: 218-226
Publication date: 15 Apr 2018
Peer-reviewed: Yes

Publication information

Journal: Water Research
Volume: 133
ISSN (Print): 0043-1354
Ratings: 
  • Scopus rating (2018): CiteScore 8.55 SJR 2.721 SNIP 2.426
Original language: English
ASJC Scopus subject areas: Ecological Modelling, Water Science and Technology, Waste Management and Disposal, Pollution
Keywords: Anaerobic digestion, Methane, Pulp and paper industry, Sedimented fibre
Source: Scopus
Source ID: 85041395267

Research output: Contribution to journalArticleScientificpeer-review

Nutrient management via struvite precipitation and recovery from various agroindustrial wastewaters: Process feasibility and struvite quality

Improving environmental protection and finding sustainable and renewable resources of nutrients are core issues in circular bioeconomy. Thus, this study evaluated the efficiency of recovering struvite, MgNH4PO4·6H2O, from different agro-industrial wastewaters (four highly loaded reject waters of anaerobically co-digested agro-industrial waste and a raw swine slurry) and assessed the quality of recovered struvite crystals and their reusability as fertilizer. The efficiency of crystallization (Ec 40–80%) and amount of struvite in the precipitate (Pp 55–94%) highly varied due to the characteristics of influent wastewaters, particularly to the content of competing elements, such as alkaline and heavy metals and total solids (TS). In particular, Ec (94, 75, 61%) and Pp (76, 66, 48%) decreased at increasing TS (0.57, 0.73, 0.99%), demonstrating the hindering effect of solid content on struvite recovery and quality. According to X-ray diffraction analysis, the structure of all isolated samples corresponded to crystalline, orthorhombic struvite, which exhibited high purity (32–48 g/kgd N, 114–132 g/kgd P, and 99–116 g/kgd Mg) containing only a few foreign elements, whose amount depended on the characteristics of the influent wastewater. All struvite contained other plant macronutrients (K, Ca) and many micronutrients (Fe, Na, Cu, Mn, Co, Zn) that further enhance its agronomic value. Therefore, this study showed that struvite can be successfully recovered from a wide range of highly loaded agroindustrial wastewaters, and that the quality of the recovered struvite could be suitable for reuse in agriculture.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Materials Science, OY Scandinavian Colloids Ltd
Contributors: Taddeo, R., Honkanen, M., Kolppo, K., Lepistö, R.
Number of pages: 7
Pages: 433-439
Publication date: 15 Apr 2018
Peer-reviewed: Yes

Publication information

Journal: Journal of Environmental Management
Volume: 212
ISSN (Print): 0301-4797
Ratings: 
  • Scopus rating (2018): CiteScore 5.32 SJR 1.206 SNIP 1.726
Original language: English
ASJC Scopus subject areas: Environmental Engineering, Waste Management and Disposal, Management, Monitoring, Policy and Law
Keywords: Crystalline purity, Heavy metals, Nutrient recycling, Solid content, Sustainable fertilizer

Bibliographical note

EXT="Kolppo, Kari"

Source: Scopus
Source ID: 85042109316

Research output: Contribution to journalArticleScientificpeer-review

Composite Hydrogels Using Bioinspired Approach with in Situ Fast Gelation and Self-Healing Ability as Future Injectable Biomaterial

Biopolymers are attractive candidates to fabricate biocompatible hydrogels, but the low water solubility of most of them at physiological pH has hindered their applications. To prepare a water-soluble derivative of chitosan (WSC) biopolymer, it was grafted with a small anionic amino acid, l-glutamic acid, using a single-step 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide coupling reaction. This resulted in a zwitterion-tethered structure onto the polymer backbone. The degree of substitution range was 13–16 ± 1.25%, which was controlled by varying the feeding reagent ratios. Differential scanning calorimetry- and X-ray diffraction-based analysis confirmed a transition from amorphous into a moderately amorphous/crystalline morphology after amino acid grafting, which made the derivative water-soluble at physiological pH. Composite hydrogels gelated within 60 s when using this WSC together with benzaldehyde-terminated 4-arm poly(ethylene glycol) as cross-linker. The compressive modulus of these hydrogels could be easily tuned between 4.0 ± 1.0 and 31 ± 2.5 kPa, either by changing the cross-linker concentration or total solid content in the final gel. The gels were injectable at the lowest cross-linker as well as total solid content, due to the enhanced elastic behavior. These hydrogels showed biodegradability during a 1 month incubation period in phosphate-buffered saline with weight remaining of 60 ± 1.5 and 44 ± 1.45% at pHs 7.4 and 6.5, respectively. The cytocompatibility of the gels was tested using the fibroblast cell line (i.e., WI-38), which showed good cell viability on the gel surface. Therefore, these hydrogels could be an important injectable biomaterial for delivery purpose in the future.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Faculty of Biomedical Sciences and Engineering, Chemistry and Bioengineering, Materials Science, Research group: Biomaterials and Tissue Engineering Group, BioMediTech, Institute of Chemical Sciences, 25120 Peshawar, Pakistan
Contributors: Khan, M., Koivisto, J., Hukka, T., Hokka, M., Kellomäki, M.
Pages: 11950-11960
Publication date: 11 Apr 2018
Peer-reviewed: Yes
Early online date: 15 Mar 2018

Publication information

Journal: ACS Applied Materials & Interfaces
Volume: 10
Issue number: 14
ISSN (Print): 1944-8244
Ratings: 
  • Scopus rating (2018): CiteScore 8.69 SJR 2.596 SNIP 1.539
Original language: English
ASJC Scopus subject areas: Materials Science(all), Chemistry(all)

Research output: Contribution to journalArticleScientificpeer-review

Process Integration Approaches to Improve the Techno-Economic Feasibility of Torrefaction Process

Over the past few years, the torrefaction process has evolved into a promising pre-treatment process to improve the properties of biomass to a level at which it is competitive with coal. However, in order to make torrefied biomass pellets an economically viable alternative to coal and wood pellets, the techno-economic feasibility of the torrefaction process needs to be improved. Thus, new process configurations are required to produce torrefied biomass pellets and other high value products from the torrefaction process. This thesis presents new process configurations, which have been evaluated with laboratory experiments, process simulations and mathematical modeling.

Two different biomass samples i.e. eucalyptus clone and pinewood were used in torrefaction experiments. Initially, the effect that torrefaction pretreatment has on the kinetics, reaction mechanisms and heat flow during biomass pyrolysis was studied using TGA and DSC analysis. The results showed that the pyrolysis reaction mechanism varied significantly with torrefaction treatment. The heat flow data from DSC showed that torrefied biomass pyrolysis requires more energy than dried biomass in order to initiate the pyrolysis reactions.

In the second stage, the anaerobic digestion of torrefaction condensate for the efficient utilization of torrefaction volatiles was studied through batch anaerobic digestion assays. Torrefaction condensate produced at 225, 275 and 300 °C was used at various substrate to inoculum ratio i.e. 0.1, 0.2 and 0.5. The methane yield was in the range of 430 - 492 mL/g volatile solids (VS) and 430 - 460 mL/g VS under mesophilic and thermophilic conditions, respectively. With the higher loading, i.e. > 0.2 VSsubstrate:VSinoculum, the production of methane was inhibited because of the inhibitory compounds in the torrefaction condensate, such as furfural and guaiacol.

Large quantities of binders are required to make the pelletization process effective and to improve the quality of the pellets. An innovative process configuration is hereby proposed for detoxifying the torrefaction condensate and to reduce the binders’ requirement. The removal of a major inhibitory compound, i.e. furfural, through adsorption using torrefied biomass as an adsorbent was also studied. The adsorption of furfural from the torrefaction condensate at 250 g/L dosage was around 54%. Finally, the influence of the detoxification of the torrefaction condensate on the AD process was studied through batch assays.

Finally, the experimental results were used to simulate industrial scale operations to evaluate the feasibility of integrating the torrefaction process with anaerobic digestion. In addition, different process integration approaches were studied to identify possible heat energy recovery options in the torrefaction process, on its own, and also when integrated with AD. The standalone torrefaction process was compared with three different process configurations, which varied according to the intended application for the produced biogas. The mass balance showed that biomethane can be produced at 369 m3/h, at 10 t/h of torrefied biomass pellets production capacity. A sensitivity analysis showed that the cost of the feedstock has a significant effect on the economics of the overall process. The economic analysis showed that the price of torrefied biomass pellets could be significantly reduced if the torrefaction process is integrated with AD.

General information

Publication status: Published
MoE publication type: G5 Doctoral dissertation (article)
Organisations: Chemistry and Bioengineering
Contributors: Doddapaneni, T. R. K. C.
Number of pages: 84
Publication date: 6 Apr 2018

Publication information

Publisher: Tampere University of Technology
ISBN (Print): 978-952-15-4119-3
ISBN (Electronic): 978-952-15-4125-4
Original language: English

Publication series

Name: Tampere University of Technology. Publication
Volume: 1539
ISSN (Print): 1459-2045

Research output: Book/ReportDoctoral thesisCollection of Articles

Metabolic Engineering of Acinetobacter baylyi ADP1 for Improved Growth and Wax Ester Production Using Components of Lignocellulosic Hydrolysates as Carbon Sources

Microorganisms can be used in bioprocesses to produce various chemicals, such as fuels, cosmetics and medical products, as an environmentally friendly alternative for chemical synthesis. In these bioprocesses the raw materials (e.g. lignocellulose) can be converted to compounds with high complexity with a minimum energy input and waste material production. The metabolic capabilities and robustness of the bioprocess host organism limit the yield and purity of the product. Molecules that currently cannot be produced efficiently with robust microbial host organisms include wax esters, which have several industrial applications and are currently produced with the Jojoba plant.

Acinetobacter baylyi ADP1 is a non-pathogenic soil bacterium that produces wax esters that can readily incorporate foreign DNA into their genome and utilize various plant-derived molecules as a carbon source. For these reasons, A. baylyi ADP1 has become a model organism of bacterial genetics and metabolism, which has led to the accumulation of a vast amount of information about its biology. This Doctor of Science thesis describes experiments where the metabolism of A. baylyi ADP1 was engineered for improved growth and wax ester production using lignocellulose-derived molecules as raw material.

With a gene knockout (rmlA) and expression of a foreign gene (pykF), it was possible to double the growth rate of A. baylyi APD1 on glucose, double the molar wax ester yield from glucose while improving product purity and collection of the cells. An additional gene knockout (poxB) improved growth and wax ester production in the presence of acetate, a common growth inhibitor found in lignocellulosic hydrolysates. A combination of these modifications led to a strain that produced 0.45 g/l of wax esters in a medium containing glucose, amino acids from casein hydrolysate and acetate as carbon sources. In addition, a biodetoxification strain for the removal of inhibitors produced in the pretreatment of lignocellulosic biomass was produced with a single gene knockout.

While significant improvements in growth and wax ester production of A. baylyi ADP1 from components of lignocellulosic hydrolysates were obtained with metabolic engineering, the wax ester production needs to be further improved if this strain is going to be used in industrial applications. The strains that were produced here can be used as platform for further improvements of wax ester production by A. baylyi ADP1.

General information

Publication status: Published
MoE publication type: G5 Doctoral dissertation (article)
Organisations: Chemistry and Bioengineering
Contributors: Kannisto, M.
Number of pages: 64
Publication date: 23 Mar 2018

Publication information

Publisher: Tampere University of Technology
ISBN (Print): 978-952-15-4100-1
ISBN (Electronic): 978-952-15-4117-9
Original language: English

Publication series

Name: Tampere University of Technology. Publication
Volume: 1532
ISSN (Print): 1459-2045

Research output: Book/ReportDoctoral thesisCollection of Articles

Thermal Isomerization of Hydroxyazobenzenes as a Platform for Vapor Sensing

Photoisomerization of azobenzene derivatives is a versatile tool for devising light-responsive materials for a broad range of applications in photonics, robotics, microfabrication, and biomaterials science. Some applications rely on fast isomerization kinetics, while for others, bistable azobenzenes are preferred. However, solid-state materials where the isomerization kinetics depends on the environmental conditions have been largely overlooked. Herein, an approach to utilize the environmental sensitivity of isomerization kinetics is developed. It is demonstrated that thin polymer films containing hydroxyazobenzenes offer a conceptually novel platform for sensing hydrogen-bonding vapors in the environment. The concept is based on accelerating the thermal cis-trans isomerization rate through hydrogen-bond-catalyzed changes in the thermal isomerization pathway, which allows for devising a relative humidity sensor with high sensitivity and quick response to relative humidity changes. The approach is also applicable for detecting other hydrogen-bonding vapors such as methanol and ethanol. Employing isomerization kinetics of azobenzenes for vapor sensing opens new intriguing possibilities for using azobenzene molecules in the future.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Aalto University
Contributors: Poutanen, M., Ahmed, Z., Rautkari, L., Ikkala, O., Priimägi, A.
Number of pages: 6
Pages: 381-386
Publication date: 20 Mar 2018
Peer-reviewed: Yes

Publication information

Journal: ACS Macro Letters
Volume: 7
Issue number: 3
ISSN (Print): 2161-1653
Ratings: 
  • Scopus rating (2018): CiteScore 5.82 SJR 2.201 SNIP 1.255
Original language: English
ASJC Scopus subject areas: Organic Chemistry, Polymers and Plastics, Inorganic Chemistry, Materials Chemistry
Source: Scopus
Source ID: 85044222959

Research output: Contribution to journalArticleScientificpeer-review

Modeling of Charge Transfer at Dye-Semiconductor Interfaces in p-Type Solar Cells

Dye-sensitized solar cells are composed of cheap and recyclable materials. These colorful and flexible cells convert sunlight into renewable energy. However, dye-sensitized solar cells are inefficient due to their low-charge current. The goal of this thesis is thus to create better understanding of the various components of these cells in order to improve their efficiencies. The main focus of dye-sensitized solar energy research lies in charge-transfer reactions between three main components: dye molecule; semiconductor surface, and electrolyte. In dye-sensitized solar cells, the charge is transferred from the excited dye molecule to the semiconductor surface. The charge is then transported to the electrode to create the electric current.

The studied components are derivatives of boron-dipyrromethene, perylene monoimide, and trisphenyl amine as dye molecules. Nickel oxide and titanium dioxide are used as semiconductor surfaces. The studied anchoring groups are carboxylate, 1,2-diol, and pyridine. These are studied in isolation, and then, their interactions in contact are investigated. In this study theoretical modeling is used, which includes the hybrid functional B3LYP and CRYSTAL09 software. The hybrid functional, B3LYP, is not widely used in studies within periodic boundary conditions such as dye-semiconductor interfaces. Thus, the mentioned systems have not been studied earlier at this level of theory.

In the first part of the study, the isolated systems, namely derivatives borondipyrromethene and titanium dioxide, are investigated. Results with BODIPY show that i) the vinylene group makes no difference for the electron transition nor orbital localization of orbitals, ii) phosphonate draws the most and carboxyl the least amount of the electron localization from the anchor, iii) methyl groups block completely the electron localization from the anchoring group, and iv) the absence of donor decreases the energy of HOMO level. BODIPY with vinylene and methyl groups were chosen for the synthesis, because the methyl groups increase the life-time of electron–hole pair. Doping with nitrogen shows that the amount of nitrogen atoms makes difference for electronic structure, yet do not distort the lattice. The electronic structure changes due to the created empty gaps states that enhance electron conductivity.

In the second part of this study, derivates of perylenemonoimide based dye molecules trisphenyl amine based anchoring groups on the NiO(100) surface and their interactions are investigated. The study with complete dye molecules on the nickel oxide surface is straightforward: the dyes’ highest occupied molecular orbital is above nickel oxide’s valence band maximum, thus, the spontaneous charge transfer is hard to obtain. Next it is shown that the anchoring group impacts the energy level alignment because of created dipole moment of the system that creates a shift within an electrostatic potential. Due to the shift, the highest occupied molecular orbitals of the dye molecule are either above (in case of carboxylate) or below (in the cases of pyridine and 1,2-diol) valence band maximum. In the case of complete molecules, which have the carboxylate as an anchoring group, HOMOs are above the VBM.

The results and analysis of the study show the importance of the size of the molecule and the anchoring group. The smaller the dye molecule, the smaller the distances are inside the interacting system, and shorter distances to transfer the charge. In the case of complete molecules, which have the carboxylate as an anchoring group, HOMOs are above the VBM. In conclusion, the largest effect is caused by the anchoring group inside the interacting system.

General information

Publication status: Published
MoE publication type: G4 Doctoral dissertation (monograph)
Organisations: Physics
Contributors: Kontkanen, O. V.
Number of pages: 117
Publication date: 2 Mar 2018

Publication information

Publisher: Tampere University of Technology
ISBN (Print): 978-952-15-4097-4
ISBN (Electronic): 978-952-15-4107-0
Original language: English

Publication series

Name: Tampere University of Technology. Publication
Volume: 1530
ISSN (Print): 1459-2045

Research output: Book/ReportDoctoral thesisMonograph

Techno-economic analysis of a power to biogas system operated based on fluctuating electricity price

This article presents a feasibility analysis of a novel operating principle based on fluctuating electricity prices for an existing biogas plant. By investing in an electrolyzer, excess electricity from renewable production can be stored as CH4 by biological methanation of H2 with CO2 originating from the biogas plant. The main components of the system are an electrolyzer that is connected to an electric grid and an anaerobic digester where the methanation takes place as well as a biogas upgrading unit. First the energy flow of the system was studied, and secondly the operation costs of the system as well as the electrolyzer investment payback time were evaluated.

The study showed that up to 40% of the electricity fed into the system can be stored as biomethane, and the system energy flow is most sensitive to the electrolyzer efficiency. The economics of the studied system depend mostly on the electrolyzer investment cost and desired target price for the CH4. The system can be run economically with current electricity prices if the electrolyzer investment costs decrease 60–72% or the price of CH4 increases 20–76% depending on the investment interest and price fluctuation scheme.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy
Contributors: Pääkkönen, A., Tolvanen, H., Rintala, J.
Number of pages: 9
Pages: 166-174
Publication date: Mar 2018
Peer-reviewed: Yes
Early online date: 12 Oct 2017

Publication information

Journal: Renewable Energy
Volume: 117
ISSN (Print): 0960-1481
Ratings: 
  • Scopus rating (2018): CiteScore 6.19 SJR 1.889 SNIP 2.075
Original language: English

Research output: Contribution to journalArticleScientificpeer-review

Critical role and modification of surface states in hematite films for enhancing oxygen evolution activity

Hematite films deposited by plasma-enhanced chemical vapor deposition of iron pentacarbonyl [Fe(CO)(5)] in an oxygen plasma were modified by postdeposition (i) oxygen plasma treatment and (ii) short annealing treatments to reduce the defects and to modify the (sub)surface states and consequently the photoelectrochemical properties. The oxygen plasma treatment resulted in the increase of particle size and augmented surface roughening by densification of grains. Moreover, it induced saturated surface states with reactive oxygen species (O-, OH-), evident in the X-ray photoelectron spectroscopy (XPS). Under standard illumination (1.5 AM; 100 mW/cm(2); 150 W xenon lamp), when compared to the pristine hematite coating (0.696 mA/cm(2) at 1.23 V versus RHE and 0.74 V-onset) the oxygen plasma-treated films showed severe deterioration in photocurrent density of 0.035 mA/cm(2) and an anodic shift in the onset potential (1.10 V-onset) due to oxygen rich surface. In a second set of experiments, the oxygen plasma-treated hematite films were briefly annealed (10 min at 750 degrees C) and the signals of Fe 2p and O 1s recovered to higher binding energies, indicating the formation of oxygen vacancies. In addition, a superior photocurrent density value of max. 1.306 mA/cm(2) at 1.23 V versus RHE to that of the pristine hematite photoanode with 0.74 V-onset was obtained. Transient absorption spectroscopy further elucidated that the oxygen plasma-induced electron trap states acting as recombination centers that are unfavorable for photoelectrochemical activity. The alteration in Fe:O stoichiometry and thus photocurrent density are corroborated by determination of water oxidation rates in annealed (7.1 s(-1)) and oxygen plasma treated (2.5 s(-1)) samples.

General information

Publication status: Published
MoE publication type: A2 Review article in a scientific journal
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Univ Cologne, University of Cologne, Inst Inorgan Chem
Contributors: Pyeon, M., Ruoko, T., Leduc, J., Goenuellue, Y., Deo, M., Tkachenko, N. V., Mathur, S.
Number of pages: 12
Pages: 455-466
Publication date: 28 Feb 2018
Peer-reviewed: Yes

Publication information

Journal: Journal of Materials Research
Volume: 33
Issue number: 4
ISSN (Print): 0884-2914
Ratings: 
  • Scopus rating (2018): CiteScore 1.91 SJR 0.654 SNIP 0.754
Original language: English
Keywords: plasma-enhanced CVD (PECVD) (deposition), thin film, surface chemistry, RAY-ABSORPTION SPECTROSCOPY, WATER-SPLITTING PERFORMANCE, ALPHA-FE2O3 PHOTOELECTRODES, SEMICONDUCTOR ELECTRODE, OXIDE PHOTOANODES, TRANSITION-METAL, XPS SPECTRA, IN-SITU, K-EDGE, OXIDATION
Source: WOS
Source ID: 000426671400007

Research output: Contribution to journalReview ArticleScientificpeer-review

UV-Blocking Synthetic Biopolymer from Biomass-Based Bifuran Diester and Ethylene Glycol

A furan-based synthetic biopolymer composed of a bifuran monomer and ethylene glycol was synthesized through melt polycondensation, and the resulting polyester was found to have promising thermal and mechanical properties. The bifuran monomer, dimethyl 2,2′-bifuran-5,5′-dicarboxylate, was prepared using a palladium-catalyzed, phosphine ligand-free direct coupling protocol. A titanium-catalyzed polycondensation procedure was found effective at polymerizing the bifuran monomer with ethylene glycol. The prepared bifuran polyester exhibited several intriguing properties including high tensile modulus. In addition, the bifuran monomer furnished the polyester with a relatively high glass transition temperature. Films prepared from the new polyester also had excellent oxygen and water barrier properties, which were found to be superior to those of poly(ethylene terephthalate). Moreover, the novel polyester also has good ultraviolet radiation blocking properties.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, University of Oulu, Research Unit of Sustainable Chemistry, P.O. Box 3000, FI-90014 Oulu, University of Oulu, Fibre and Particle Engineering Research Unit, P.O. Box 4300, FI-90014 Oulu
Contributors: Kainulainen, T. P., Sirviö, J. A., Sethi, J., Hukka, T. I., Heiskanen, J. P.
Number of pages: 8
Pages: 1822-1829
Publication date: 21 Feb 2018
Peer-reviewed: Yes
Early online date: 21 Feb 2018

Publication information

Journal: Macromolecules
Volume: 51
Issue number: 5
ISSN (Print): 0024-9297
Ratings: 
  • Scopus rating (2018): CiteScore 5.88 SJR 2.243 SNIP 1.475
Original language: English
ASJC Scopus subject areas: Chemistry(all), Materials Science(all)
Keywords: Biopolymers, Synthesis, Characterization, Thermal analysis, Spectroscopy

Research output: Contribution to journalArticleScientificpeer-review

Pot-economy autooxidative condensation of 2-Aryl-2-lithio-1,3-dithianes

The autoxidative condensation of 2-aryl-2-lithio-1,3-dithianes is here reported. Treatment of 2-aryl-1,3-dithianes with n-BuLi in the absence of any electrophile leads to condensation of three molecules of 1,3-dithianes and formation of highly functionalized α-thioether ketones orthothioesters in 51-89% yields upon air exposure. The method was further expanded to benzaldehyde dithioacetals, affording corresponding orthothioesters and α-thioether ketones in 48-97% yields. The experimental results combined with density functional theory studies support a mechanism triggered by the autoxidation of 2-aryl-2-lithio-1,3-dithianes to yield a highly reactive thioester that undergoes condensation with two other molecules of 2-aryl-2-lithio-1,3-dithiane.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Faculdade de Farmacia da Universidade de Lisboa, Jyväskylän yliopisto
Contributors: Vale, J. R., Rimpiläinen, T., Sievänen, E., Rissanen, K., Afonso, C. A., Candeias, N. R.
Number of pages: 11
Pages: 1948-1958
Publication date: 16 Feb 2018
Peer-reviewed: Yes

Publication information

Journal: Journal of Organic Chemistry
Volume: 83
Issue number: 4
ISSN (Print): 0022-3263
Ratings: 
  • Scopus rating (2018): CiteScore 4.57 SJR 1.607 SNIP 0.952
Original language: English
ASJC Scopus subject areas: Organic Chemistry
Electronic versions: 

Bibliographical note

INT=keb,"Vale, Joao R."

Source: Scopus
Source ID: 85042195347

Research output: Contribution to journalArticleScientificpeer-review

Quantitative Real-time PCR Monitoring Dynamics Of Thermotoga Neapolitana In Synthetic Co-Culture For Biohydrogen Production

This study demonstrates the potential for biohydrogen production in a co-culture of two ecologically distant species, Thermatoga neapolitana and Caldicellulosiruptor saccharolyticus, and the development of a quantitative real-time PCR (qPCR) method for quantifying the hyperthermophilic bacterium of the genus Thermotoga. Substrate utilization and H2 production performance was compared to those of their individual cultures. The highest H2 yields obtained were 2.7 ± 0.05, 2.5 ± 0.07 and 2.8 ± 0.09 mol H2/mol glucose for C. saccharolyticus, T. neapolitana, and their co-culture respectively. Statistical analysis comparing the H2 production rate of the co-culture to either C. saccahrolyticus or T. neapolitana pure cultures indicated a significant difference in the H2 production rate (p < 0.05: t-test), with the highest rate of H2 production (36.02 mL L−1 h−1) observed from the co-culture fermentations. In order to monitor the presence of T. neapolitana in the bioprocess, we developed a qPCR method using 16S rRNA gene and hydrogenase (hydA) gene targets. The qPCR data using hydA primers specific to T. neapolitana showed an increase in hydA gene copies from 3.32 × 107 to 4.4 × 108hydA gene copies per mL confirming the influence of T. neapolitana in the synthetic consortium.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy
Contributors: Okonkwo, O., Lakaniemi, A., Santala, V., Karp, M., Mangayil, R.
Number of pages: 9
Pages: 3133-3141
Publication date: 8 Feb 2018
Peer-reviewed: Yes

Publication information

Journal: International Journal of Hydrogen Energy
Volume: 43
Issue number: 6
ISSN (Print): 0360-3199
Ratings: 
  • Scopus rating (2018): CiteScore 4.16 SJR 1.1 SNIP 1.128
Original language: English

Research output: Contribution to journalArticleScientificpeer-review

Controlled Growth of Supported ZnO Inverted Nanopyramids with Downward Pointing Tips

High purity porous ZnO nanopyramids with controllable properties are grown on their tips on Si(100) substrates by means of a catalyst-free vapor phase deposition route in a wet oxygen reaction environment. The system degree of preferential [001] orientation, as well as nanopyramid size, geometrical shape, and density distribution, can be finely tuned by varying the growth temperature between 300 and 400 °C, whereas higher temperatures lead to more compact systems with a three-dimensional (3D) morphology. A growth mechanism of the obtained ZnO nanostructures based on a self-catalytic vapor-solid (VS) mode is proposed, in order to explain the evolution of nanostructure morphologies as a function of the adopted process conditions. The results obtained by a thorough chemico-physical characterization enable us to get an improved control over the properties of ZnO nanopyramids grown by this technique. Taken together, they are of noticeable importance not only for fundamental research on ZnO nanomaterials with controlled nano-organization but also to tailor ZnO functionalities in view of various potential applications.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Supramolecular photochemistry, Chemistry and Bioengineering, Universita degli Studi di Padova, Italy, Universiteit Antwerpen, VTT Technical Research Centre of Finland
Contributors: Barreca, D., Carraro, G., Maccato, C., Altantzis, T., Kaunisto, K., Gasparotto, A.
Number of pages: 9
Pages: 2579-2587
Publication date: Feb 2018
Peer-reviewed: Yes

Publication information

Journal: Crystal Growth and Design
Volume: 18
Issue number: 4
ISSN (Print): 1528-7483
Ratings: 
  • Scopus rating (2018): CiteScore 4.01 SJR 1.046 SNIP 1.107
Original language: English
ASJC Scopus subject areas: Chemistry(all), Materials Science(all), Condensed Matter Physics
Source: Scopus
Source ID: 85044992194

Research output: Contribution to journalArticleScientificpeer-review

Ultralong 20 Milliseconds Charge Separation Lifetime for Photoilluminated Oligophenylenevinylene–Azafullerene Systems

The synthesis and characterization of oligophenylenevinylene (OPV)–azafullerene (C59N) systems in the form of OPV–C59N donor–acceptor dyad 1 and C59N–OPV–C59N acceptor–donor–acceptor triad 2 is accomplished. Photoinduced electronic interactions between OPV and C59N within 1 and 2 are assessed by UV–vis and photoluminescence. The redox properties of 1 and 2 are investigated, revealing a set of one-electron oxidation and three one-electron reduction processes owed to OPV and C59N, respectively. The electrochemical bandgap for 1 and 2 is calculated as 1.44 and 1.53 eV, respectively, and the free energy for the formation of the charge-separated state for 1 and 2 via the singlet-excited state of OPV is found negative, proving a thermodynamically favorable the process. Photoexcitation assays are performed in toluene and o-dichlorobenzene (oDCB) and the reactions are monitored with time-resolved absorption and emission spectroscopies. Competitive photoinduced energy and electron transfer are identified to occur in both systems, with the former being dominant in 2. Markedly, the charge-separated state in oDCB exhibits a much longer lifetime compared to that in toluene, reaching 20 ms for 1, the highest ever reported value for fullerene-based materials. These unprecedented results are rationalized by considering conformational phenomena affecting the charge-separated state.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials
Contributors: Rotas, G., Stranius, K., Tkachenko, N., Tagmatarchis, N.
Publication date: Feb 2018
Peer-reviewed: Yes
Early online date: 18 Dec 2017

Publication information

Journal: Advanced Functional Materials
Volume: 28
Issue number: 7
Article number: 1702278
ISSN (Print): 1616-3028
Ratings: 
  • Scopus rating (2018): CiteScore 14.58 SJR 5.646 SNIP 2.347
Original language: English
Keywords: azafullerenes, charge separation, oligophenylenevinylenes
Source: Bibtex
Source ID: urn:2bc506961085ad42222326b1b84a9083

Research output: Contribution to journalArticleScientificpeer-review

Concentration-dependent photophysical switching in mixed self-assembled monolayers of pentacene and perylenediimide on gold nanoclusters

Photophysical control and switching on organic-inorganic hybrid interfaces are of great interest in diverse fundamental and applicative research areas. 6,13-Bis(triisopropylsilylethynyl)pentacene (TP) is well-known to exhibit efficient singlet fission (SF) for generation of high-yield triplet excited states in aggregated forms, whereas perylenediimide (PDI) ensembles show the characteristic excimer formation. Additionally, a combination of pentacene (electron donor: D) and PDI (electron acceptor: A) is expected to undergo an efficient photoinduced electron transfer (PET), and absorption of two chromophores combined covers the entire visible region. Therefore, the concentration-dependent mixed self-assembled monolayers (SAMs) composed of two chromophores enable us to control and switch the photophysical processes on a surface. In this work, a series of mixed SAMs composed of TP and PDI units on gold nanoclusters (GNCs) were newly synthesized by changing the relative molecular concentration ratios. Structural control of mixed SAMs on a gold surface based on the concentration ratios was successfully achieved. Time-resolved femtosecond and nanosecond transient absorption measurements clearly demonstrate photophysical control and switching of the above competitive reactions such as SF, electron transfer (ET) and excimer formation. The maximum quantum yields of triplet states (ΦT = ∼170%) and electron transfer (ΦET = ∼95%) were quantitatively evaluated by changing the concentration ratios. The rate constants of SF and excimer processes are largely dependent on the concentration ratios, whereas the rate constants of ET processes approximately remain constant. These findings are also discussed based on the statistical framework of the assembly of chromophores on the gold surface.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Keio University, Tohoku University
Contributors: Kato, D., Sakai, H., Araki, Y., Wada, T., Tkachenko, N. V., Hasobe, T.
Number of pages: 12
Pages: 8695-8706
Publication date: 1 Jan 2018
Peer-reviewed: Yes

Publication information

Journal: Physical Chemistry Chemical Physics
Volume: 20
Issue number: 13
ISSN (Print): 1463-9076
Ratings: 
  • Scopus rating (2018): CiteScore 3.69 SJR 1.31 SNIP 0.981
Original language: English
ASJC Scopus subject areas: Physics and Astronomy(all), Physical and Theoretical Chemistry
Source: Scopus
Source ID: 85044838671

Research output: Contribution to journalArticleScientificpeer-review

Ortho-Fluorination of azophenols increases the mesophase stability of photoresponsive hydrogen-bonded liquid crystals

Photoresponsive liquid crystals (LCs) whose alignment can be controlled with UV-Visible light are appealing for a range of photonic applications. From the perspective of exploring the interplay between the light response and the self-assembly of the molecular components, supramolecular liquid crystals are of particular interest. They allow elaborating the structure-property relationships that govern the optical performance of LC materials by subtle variation of the chemical structures of the building blocks. Herein we present a supramolecular system comprising azophenols and stilbazoles as hydrogen-bond donors and acceptors, respectively, and show that ortho-fluorination of the azophenol dramatically increases the thermal stability of the LC phases, an important characteristics in their further utilization in photonics. The systems exhibit fast photoinduced order-disorder transitions, and rapid recovery of the liquid-crystalline state once the light irradiation is ceased, due to the photochemical properties of azophenols.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, University of Duisburg-Essen
Contributors: Saccone, M., Kuntze, K., Ahmed, Z., Siiskonen, A., Giese, M., Priimagi, A.
Number of pages: 6
Pages: 9958-9963
Publication date: 1 Jan 2018
Peer-reviewed: Yes

Publication information

Journal: Journal of Materials Chemistry C
Volume: 6
Issue number: 37
ISSN (Print): 2050-7534
Ratings: 
  • Scopus rating (2018): CiteScore 6.28 SJR 1.885 SNIP 1.321
Original language: English
ASJC Scopus subject areas: Chemistry(all), Materials Chemistry
Electronic versions: 
URLs: 
Source: Scopus
Source ID: 85054152271

Research output: Contribution to journalArticleScientificpeer-review

A Bioscreening Technique for Ultraviolet Irradiation Protective Natural Substances

Ultraviolet radiation (UV-R) causes genotoxic and aging effects on skin, and sunscreens are used to alleviate the damage. However, sunscreens contain synthetic shielding agents that can cause harmful effects in the environment. Nature-derived substances may have potential as replacement materials for the harmful sunscreen chemicals. However, screening of a broad range of samples is tedious, and often requires a separate genotoxicity assessment. We describe a simple microplate technique for the screening of UV protective substances using a recombinant Escherichia coli biosensor. Both absorbance-based and bioactivity-based shields can be detected with simultaneous information about the sample genotoxicity. With this technique, a controversial sunscreen compound, oxybenzone offers physical or absorbance-based shield but appears genotoxic at higher concentrations (3.3 mg/mL). We also demonstrate that pine needle extract (PiNe) shields the biosensor from UV-R in a dose-dependent manner without showing genotoxicity. The physical shield of 5 mg/mL PiNe was similar to that of one of the most common UV-shielding compound TiO2 concentration 0.80 mg/mL. The bioactivity-based shield of PiNe also reaches the extent of the physical shield with the highest concentration (3.3 mg/mL). We conclude that our technique is suitable in detecting the UV-shielding potential of natural substances, and gives simultaneous information on genotoxicity.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, Natural Resources Institute Finland (Luke)
Contributors: Tienaho, J., Poikulainen, E., Sarjala, T., Muilu-Mäkelä, R., Santala, V., Karp, M.
Pages: 1273-1280
Publication date: 2018
Peer-reviewed: Yes
Early online date: 2018

Publication information

Journal: Photochemistry and Photobiology
Volume: 94
Issue number: 6
ISSN (Print): 0031-8655
Ratings: 
  • Scopus rating (2018): CiteScore 2.35 SJR 0.806 SNIP 0.883
Original language: English
ASJC Scopus subject areas: Biochemistry, Physical and Theoretical Chemistry

Bibliographical note

INT=keb,"Poikulainen, Emmi"

Source: Scopus
Source ID: 85050664471

Research output: Contribution to journalArticleScientificpeer-review

Adsorption of furfural from torrefaction condensate using torrefied biomass

Torrefaction is a biomass energy densification process that generates a major byproduct in the form of torrefaction condensate. Microbial conversion of torrefaction condensate could be an attractive option for energy integration within torrefaction process. However, torrefaction condensate contains several compounds, such as furfural, 5-hydroxymethylfurfural and guaiacol that are inhibitory to microbes. In this study, for the first time, we reported detoxification of torrefaction condensate, by removing the major inhibitory compound furfural, using torrefied biomass and later used the detoxified torrefaction condensate for anaerobic digestion. The effect of varying torrefaction temperature (225–300 °C), torrefied biomass dosage (25–250 g/L), initial pH (2.0–9.0), and contact time (1–12 h) on furfural adsorption was studied with batch adsorption experiments. The furfural adsorption on torrefied biomass was best represented by pseudo second order kinetic model. The adsorption of furfural and other inhibitory compounds on torrefied biomass was likely a hydrophobic interaction. A maximum of 60% of furfural was adsorbed from torrefaction condensate containing 9000 mg furfural/L using 250 g/L of torrefied biomass in batch adsorption. For, column (20 mm internal diameter and 200 mm bed height), the saturation time for furfural adsorption was around 50 min. Anaerobic digestion of the detoxified torrefaction condensate shows that the lag phase in methane production was reduced from 25 d to 15 d for 0.2 volatile solid (VS)substrate:VSinoculum loading. The study shows that torrefaction condensate can be effectively detoxified using torrefied biomass for microbial conversion and can be integrated within the torrefied biomass pellet production process.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, Helmholtz-Zentrum Dresden-Rossendorf, Univ of Oulu
Contributors: Doddapaneni, T. R. K. C., Jain, R., Praveenkumar, R., Rintala, J., Romar, H., Konttinen, J.
Number of pages: 11
Pages: 558-568
Publication date: 2018
Peer-reviewed: Yes
Early online date: 2017

Publication information

Journal: Chemical Engineering Journal
Volume: 334
ISSN (Print): 1385-8947
Ratings: 
  • Scopus rating (2018): CiteScore 8.47 SJR 2.066 SNIP 1.941
Original language: English
ASJC Scopus subject areas: Chemistry(all), Environmental Chemistry, Chemical Engineering(all), Industrial and Manufacturing Engineering
Keywords: Anaerobic digestion, Detoxification, Energy densification, Pellets, Torrefaction volatiles
Source: Scopus
Source ID: 85033666908

Research output: Contribution to journalArticleScientificpeer-review

Archaea are prominent members of the prokaryotic communities colonizing common forest mushrooms

In this study, the abundance and composition of prokaryotic communities associated with the inner tissue of fruiting bodies of Suillus bovinus, Boletus pinophilus, Cantharellus cibarius, Agaricus arvensis, Lycoperdon perlatum, and Piptoporus betulinus were analyzed using culture-independent methods. Our findings indicate that archaea and bacteria colonize the internal tissues of all investigated specimens and that archaea are prominent members of the prokaryotic community. The ratio of archaeal 16S rRNA gene copy numbers to those of bacteria was >1 in the fruiting bodies of four out of six fungal species included in the study. The largest proportion of archaeal 16S rRNA gene sequences belonged to thaumarchaeotal classes Terrestrial group, Miscellaneous Crenarchaeotic Group (MCG), and Thermoplasmata. Bacterial communities showed characteristic compositions in each fungal species. Bacterial classes Gammaproteobacteria, Actinobacteria, Bacilli, and Clostridia were prominent among communities in fruiting body tissues. Bacterial populations in each fungal species had different characteristics. The results of this study imply that fruiting body tissues are an important habitat for abundant and diverse populations of archaea and bacteria.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Department of Microbiology, University of Helsinki, Turku University of Applied Science
Contributors: Rinta-Kanto, J. M., Pehkonen, K., Sinkko, H., Tamminen, M. V., Timonen, S.
Number of pages: 11
Pages: 716-726
Publication date: 2018
Peer-reviewed: Yes

Publication information

Journal: Canadian Journal of Microbiology
Volume: 64
Issue number: 10
ISSN (Print): 0008-4166
Ratings: 
  • Scopus rating (2018): CiteScore 1.65 SJR 0.613 SNIP 0.649
Original language: English
ASJC Scopus subject areas: Microbiology, Immunology, Applied Microbiology and Biotechnology, Molecular Biology, Genetics
Keywords: Archaea, Bacteria, Mushroom, qPCR, Sequencing
Electronic versions: 
Source: Scopus
Source ID: 85054057146

Research output: Contribution to journalArticleScientificpeer-review

Bio-electrochemical conversion of industrial wastewater-COD combined with downstream methanol synthesis-an economic and life cycle assessment

Herein, a techno-economic and environmental performance evaluation (i.e. Life Cycle Assessment (LCA)) of a 45 kW Microbial Electrolysis Cell (MEC) system is presented in the context of industrial wastewater remediation. This system produces H2 and CO2-suitable for downstream CH3OH synthesis-based on the bio-electrochemical conversion of chemical industry wastewater with an organic content of 3.9 g(COD) L-1. A cost-benefit analysis indicates that the MEC system hardware costs, share of CO2 captured from the MEC and MEC operating current density (i.e. 1.0 mA cm-2) are crucial parameters influencing the total cost and represent areas for potential cost reductions. It was established based on the present study that MEC system operation with renewable electricity leads to H2 production costs of 4-5.7€ kg(H2)-1 (comparable to H2O electrolysis) and CH3OH production costs of 900€ t(CH3OH)-1. At the current CH3OH market prices, however, the production is currently not profitable. In turn, the cost-efficient construction of the MEC system and the use of less expensive materials could lead to improved CH3OH production economics based on this route. Our results indicate that the use of low-cost materials has greater potential with regard to cost reduction compared to reducing the internal resistance and polarization losses via the use of expensive high-performance materials in MEC construction. A complementary LCA of the proposed system, based on a "cradle-to-gate" definition, indicates that waste-based is superior to fossil-based CH3OH production with respect to global warming potential and cumulated fossil energy demand, provided the system is operated with 100% renewable electricity and CO2 sourced only from the MEC. However, with regard to the impact categories Metal Depletion and Freshwater Eutrophication Potential, the system was found to perform less satisfactorily (i.e. in comparison with fossil-based CH3OH production).

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Fraunhofer Institute for Solar Energy Systems ISE, Albert-Ludwig-University of Freiburg, Karlsruhe Institute of Technology, Insitute for Technical Physics, Germany, University of Freiburg, Laboratory for MEMS Applications, University of Bremen
Contributors: Streeck, J., Hank, C., Neuner, M., Gil-Carrera, L., Kokko, M., Pauliuk, S., Schaadt, A., Kerzenmacher, S., White, R. J.
Number of pages: 21
Pages: 2742-2762
Publication date: 2018
Peer-reviewed: Yes

Publication information

Journal: Green Chemistry
Volume: 20
Issue number: 12
ISSN (Print): 1463-9262
Ratings: 
  • Scopus rating (2018): CiteScore 9.43 SJR 2.517 SNIP 1.815
Original language: English
ASJC Scopus subject areas: Environmental Chemistry, Pollution
Source: Scopus
Source ID: 85048986666

Research output: Contribution to journalArticleScientificpeer-review

Composition and role of the attached and planktonic microbial communities in mesophilic and thermophilic xylose-fed microbial fuel cells

A mesophilic (37 °C) and a thermophilic (55 °C) two-chamber microbial fuel cell (MFC) were studied and compared for their power production from xylose and the microbial communities involved. The anode-Attached, membrane-Attached, and planktonic microbial communities, and their respective active subpopulations, were determined by next generation sequencing (Illumina MiSeq), based on the presence and expression of the 16S rRNA gene. Geobacteraceae accounted for 65% of the anode-Attached active microbial community in the mesophilic MFC, and were associated to electricity generation likely through direct electron transfer, resulting in the highest power production of 1.1 W m-3. A lower maximum power was generated in the thermophilic MFC (0.2 W m-3), likely due to limited acetate oxidation and the competition for electrons by hydrogen oxidizing bacteria and hydrogenotrophic methanogenic archaea. Aerobic microorganisms, detected among the membrane-Attached active community in both the mesophilic and thermophilic MFC, likely acted as a barrier for oxygen flowing from the cathodic chamber through the membrane, favoring the strictly anaerobic exoelectrogenic microorganisms, but competing with them for xylose and its degradation products. This study provides novel information on the active microbial communities populating the anodic chamber of mesophilic and thermophilic xylose-fed MFCs, which may help in developing strategies to favor exoelectrogenic microorganisms at the expenses of competing microorganisms.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, Natl. University of Ireland, Galway, Institute for Water Education, Hydraulic and Environmental Engineering (IHE) Inst. for Water Education
Contributors: Dessì, P., Porca, E., Haavisto, J., Lakaniemi, A., Collins, G., Lens, P. N.
Number of pages: 12
Pages: 3069-3080
Publication date: 2018
Peer-reviewed: Yes

Publication information

Journal: RSC Advances
Volume: 8
Issue number: 6
ISSN (Print): 2046-2069
Ratings: 
  • Scopus rating (2018): CiteScore 3.16 SJR 0.807 SNIP 0.785
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all)
Electronic versions: 
Source: Scopus
Source ID: 85040867034

Research output: Contribution to journalArticleScientificpeer-review

Conjugated Heat Transfer Simulation of a Fin-and-Tube Heat Exchanger

Heat transfer and pressure drop of a fin-and-tube heat exchanger are studied by taking into account the conjugated heat transfer between the flow and the fin. The temperature distribution of the fin is calculated in respect to the convective heat transfer of the air flowing through the tube bank channel. Contemporary enhancement methods emphasize the importance of local turbulence augmentation which effects the convective heat transfer. In this paper, the importance of conjugated heat transfer, where the temperature of the flow and fin are coupled together is emphasized and compared with a constant surface temperature boundary condition simulation and experiment, which are found in the literature.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, Mechanical Engineering and Industrial Systems
Contributors: Välikangas, T., Karvinen, R.
Number of pages: 9
Pages: 1192-1200
Publication date: 2018
Peer-reviewed: Yes
Early online date: 12 Sep 2017

Publication information

Journal: Heat Transfer Engineering
Volume: 39
Issue number: 13-14
ISSN (Print): 0145-7632
Ratings: 
  • Scopus rating (2018): CiteScore 1.83 SJR 0.818 SNIP 0.991
Original language: English
ASJC Scopus subject areas: Condensed Matter Physics, Mechanical Engineering, Fluid Flow and Transfer Processes
Source: Scopus
Source ID: 85029408517

Research output: Contribution to journalArticleScientificpeer-review

Effect of elevated nitrate and sulfate concentrations on selenate removal by mesophilic anaerobic granular sludge bed reactors

Simultaneous removal of selenate (SeO42-), nitrate (NO3-) and sulfate (SO42-), typically present in Se-contaminated wastewaters, by Eerbeek anaerobic granular sludge, was investigated in batch and continuous bioreactor experiments. Batch experiments showed that SeO42- removal was enhanced to 91% in simulated wastewater with SeO42- + NO3- + SO42- (1 : 40 : 100 SeO42- : NO3- : SO42- molar ratios) compared to simulated wastewater with SeO42- alone (67%). SeO42- removal was severely impacted by high concentrations of SO42- (SeO42- : SO42- > 1 : 300). Removal of SeO42-, NO3- and SO42- at a 1 : 40 : 100 ratio was studied in a 2 L lab-scale upflow anaerobic sludge blanket (UASB) reactor operated at 20 [degree]C, a 24 h hydraulic retention time and a 2 g COD L-1 day-1 organic loading rate using lactate as the electron donor. The removal efficiencies were stabilized at 100, 30 and 80% for NO3-, SO42- and total Se, respectively, during 92 days of UASB operation. The total Se removal efficiencies dropped to 47% or even to a negative value when, respectively, SO42- and NO3- were sequentially excluded from the influent. Speciation of Se, particularly the microbial production of colloidal Se0 levels, was influenced by both SO42- and NO3-. The results presented here demonstrate that UASB reactors are capable of removing SeO42- in the presence of millimolar concentrations of NO3- and SO42- typically found in Se-contaminated wastewaters.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, UNESCO-IHE Institute for Water Education
Contributors: Tan, L. C., Nancharaiah, Y. V., van Hullebusch, E. D., Lens, P. N. L.
Pages: 303-314
Publication date: 2018
Peer-reviewed: Yes
Early online date: 5 Dec 2017

Publication information

Journal: Environmental Science: Water Research & Technology
Volume: 4
Issue number: 2
ISSN (Print): 2053-1400
Ratings: 
  • Scopus rating (2018): CiteScore 4.02 SJR 1.104 SNIP 1.081
Original language: English
Source: Bibtex
Source ID: urn:83b997c5e222c3328f8a2e876e3d3da8

Research output: Contribution to journalArticleScientificpeer-review

Effect of N/S ratio on anoxic thiosulfate oxidation in a fluidized bed reactor: Experimental and artificial neural network model analysis

Anoxic thiosulfate (S2O3 2−) oxidation using autotrophic denitrification by a mixed culture of nitrate reducing, sulfur oxidizing bacteria (NR-SOB) was studied in a fluidized bed reactor (FBR). The long-term performance of the FBR was evaluated for 306 days at three nitrogen-to-sulfur (N/S) molar ratios (0.5, 0.3 and 0.1) and a hydraulic retention time (HRT) of 5 h. S2O3 2− removal efficiencies >99% were obtained at a N/S ratio of 0.5 and a S2O3 2− and nitrate (NO3 ) loading rate of 820 (±84) mg S-S2O3 2− L−1 d−1 and 173 (±10) mg N-NO3 L−1 d−1, respectively. The S2O3 2− removal efficiency decreased to 76% and 26% at N/S ratios of 0.3 and 0.1, respectively, and recovered to 80% within 3 days after increasing the N/S ratio from 0.1 back to 0.5. The highest observed half-saturation (Ks) and inhibition (KI) constants of the biofilm-grown NR-SOB obtained from batch cultivations were 172 and 800 mg S-S2O3 2− L−1, respectively. Thiobacilus denitrificans was the dominant microorganism in the FBR. Artificial neural network modeling successfully predicted S2O3 2− and NO3 removal efficiencies and SO4 2− production in the FBR. Additionally, results from the sensitivity analysis showed that the effluent pH was the most influential parameter affecting the S2O3 2− removal efficiency.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Hydraulic and Environmental Engineering (IHE) Inst. for Water Education, University of Cassino and Southern Lazio, ENEA/CREATE/Università Degli Studi Napoli Federico II
Contributors: Khanongnuch, R., Di Capua, F., Lakaniemi, A., Rene, E. R., Lens, P. N.
Pages: 171-181
Publication date: 2018
Peer-reviewed: Yes
Early online date: 1 Jan 2018

Publication information

Journal: Process Biochemistry
Volume: 68
ISSN (Print): 1359-5113
Ratings: 
  • Scopus rating (2018): SJR 0.754 SNIP 1.018
Original language: English
ASJC Scopus subject areas: Bioengineering, Biochemistry, Applied Microbiology and Biotechnology
Keywords: Anoxic thiosulfate oxidation, Artificial neutral network, Kinetic constants, Nitrate reducing-sulfur oxidizing bacteria, Thiobacilus denitrificans
URLs: 
Source: Scopus
Source ID: 85044110451

Research output: Contribution to journalArticleScientificpeer-review

Effects of Biomass Type, Carbonization Process, and Activation Method on the Properties of Bio-Based Activated Carbons

Activated carbons (AC) serve as adsorbents in various applications requiring specific functionalities. In this study, the effects of biomass type, pre-carbonization process, and activation method on the properties of ACs were investigated. Chemical (KOH and H3PO4) and physical (CO2) activations were performed on slow pyrolyzed and hydrothermally carbonized (HTC) biochars produced from two feedstocks, willow and Scots pine bark (SPB). In addition, the adsorption capacities of the ACs were tested with two dyes and zinc metal. Distinct differences were found between the biochars and ACs regarding pore size distributions, surface area (238 - 3505 m(2) g(-1)), and surface chemistry. KOH activation produced highly microporous ACs from all biochars, whereas with H3PO4 and CO2 there was also increase in the meso- and macroporosity with the HTC biochars. Adsorption capacity for dyes was dependent on the surface area, while for zinc it depended on AC's pH. The results provide interesting insights into tailoring ACs for specific applications.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Faculty of Biomedical Sciences and Engineering, VTT Tech Res Ctr Finland Ltd, VTT Technical Research Center Finland, Univ Oulu, University of Oulu, Res Unit Sustainable Chem, Nat Resources Inst Finland Luke, Natural Resources Institute Finland (Luke)
Contributors: Siipola, V., Tamminen, T., Kalli, A., Lahti, R., Romar, H., Rasa, K., Keskinen, R., Hyvaluoma, J., Hannula, M., Wikberg, H.
Number of pages: 27
Pages: 5976-6002
Publication date: 2018
Peer-reviewed: Yes

Publication information

Journal: BioResources
Volume: 13
Issue number: 3
ISSN (Print): 1930-2126
Ratings: 
  • Scopus rating (2018): CiteScore 1.45 SJR 0.431 SNIP 0.728
Original language: English
Keywords: Biochar, Activated carbon, Bio-based activated carbon, Willow, Pine bark, X-ray tomography, PHOSPHORIC-ACID ACTIVATION, HYDROTHERMAL CARBONIZATION, CHEMICAL ACTIVATION, AGRICULTURAL RESIDUES, POROSITY DEVELOPMENT, H3PO4 ACTIVATION, POROUS CARBONS, FUEL-CELL, ADSORPTION, WASTE
Source: WOS
Source ID: 000440506300087

Research output: Contribution to journalArticleScientificpeer-review

Efficient photon upconversion at remarkably low annihilator concentrations in a liquid polymer matrix: when less is more

A green-to-blue triplet-triplet annihilation upconversion of 24.5% quantum yield was achieved at a remarkably low 600 μM annihilator concentration in a viscous polymer matrix. This was made possible by utilizing a ZnTPP-based photosensitizer with exceptionally long 11 ms phosphorescence lifetime. Higher 3 mM annihilator concentration resulted in lower 24% upconversion quantum yield.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering
Contributors: Durandin, N. A., Isokuortti, J., Efimov, A., Vuorimaa-Laukkanen, E., Tkachenko, N. V., Laaksonen, T.
Number of pages: 4
Pages: 14029-14032
Publication date: 2018
Peer-reviewed: Yes

Publication information

Journal: Chemical Communications
Volume: 54
Issue number: 99
ISSN (Print): 1359-7345
Ratings: 
  • Scopus rating (2018): CiteScore 6.12 SJR 2.177 SNIP 1.133
Original language: English
ASJC Scopus subject areas: Catalysis, Electronic, Optical and Magnetic Materials, Ceramics and Composites, Chemistry(all), Surfaces, Coatings and Films, Metals and Alloys, Materials Chemistry
Keywords: triplet-triplet annihilation, triplet-triplet energy transfer, triplet state lifetime, upconversion, triplet fusion
URLs: 
Source: Scopus
Source ID: 85058301188

Research output: Contribution to journalArticleScientificpeer-review

Electronic waste as a secondary source of critical metals: Management and recovery technologies

The wealth of the society depends on several metals, including base metals, precious metals and increasingly rare earth elements (REE). They are collectively termed as technology metals. Numerous applications stimulated the use of technology metals, and their supply is at stake, owing to the high demand and uneven geographical distribution of these metals. Their stable supply is crucial for the transition to a sustainable and circular economy. There is an increasing interest in secondary sources of these metals. This article outlines the global state of electronic waste, its management and the latest technological developments in metal recovery from various streams of electronic waste. An emphasis is given to printed circuit boards (PCB), hard disc drives (HDD) and displays regarding their critical metal content. Physical, pyrometallurgical and (bio)hydrometallurgical metal recovery technologies are overviewed. In addition, perspectives on electronic waste as a secondary source of critical metals are given.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Université Paris-Est, Hydraulic and Environmental Engineering (IHE) Inst. for Water Education
Contributors: Işildar, A., Rene, E. R., van Hullebusch, E. D., Lens, P. N.
Pages: 296-312
Publication date: 2018
Peer-reviewed: Yes

Publication information

Journal: Resources, Conservation and Recycling
Volume: 135
ISSN (Print): 0921-3449
Ratings: 
  • Scopus rating (2018): CiteScore 6.82 SJR 1.541 SNIP 2.258
Original language: English
ASJC Scopus subject areas: Waste Management and Disposal, Economics and Econometrics
Keywords: Critical metals, Hard disc drives (HDD), Liquid crystal displays (LCD), Printed circuit boards (PCB), Secondary source, WEEE
Source: Scopus
Source ID: 85030839291

Research output: Contribution to journalArticleScientificpeer-review

Fin-and-tube heat exchanger enhancement with a combined herringbone and vortex generator design

Vortex generators (VGs) are the most commonly investigated enhancement methods in the field of improved heat exchangers. The aim of present work is to study the effect of VGs in a fin-and-tube heat exchanger (FTHE) with herringbone fin shape. The delta winglet VG design with length (s) and height (H) is selected based on previous studies. The investigated VG design is simple and considered realistic from the manufacturing point of view. The combined enhancement with herringbone fin and the VG is evaluated by simulating the conjugate heat transfer and the air flow. The structured mesh is created for both solid and fluid domains to solve the model numerically using a coupled open source solver in OpenFOAM. The influence of flow condition on the performance enhancement is studied by changing the Reynolds number in a range Re=1354–6157. The study showed that VGs not only increase the heat transfer in the herringbone fin but also decrease the pressure drop. The highest and longest investigated VG design is found to perform the best because of its ability to delay the flow detachment from the tube, to feed high kinetic energy flow to the recirculation zone and to create longitudinal vortices in the downstream region from the VG. The fin with VG design s=0.5D and H=0.6Fp enhances the overall performance by 5.23% in comparison to the fin without VG. The results demonstrated the usefulness of VGs for the performance enhancement in connection with a herringbone fin design.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Bio- and Circular Economy, Physics, Chemistry and Bioengineering, Aalborg University
Contributors: Välikangas, T., Singh, S., Sørensen, K., Condra, T.
Number of pages: 15
Pages: 602-616
Publication date: 2018
Peer-reviewed: Yes
Early online date: 2017

Publication information

Journal: International Journal of Heat and Mass Transfer
Volume: 118
ISSN (Print): 0017-9310
Ratings: 
  • Scopus rating (2018): CiteScore 4.73 SJR 1.624 SNIP 1.92
Original language: English
ASJC Scopus subject areas: Condensed Matter Physics, Mechanical Engineering, Fluid Flow and Transfer Processes
Keywords: Conjugate heat transfer, Fin-and-tube heat exchanger, Herringbone fin, Vortex generator
Source: Scopus
Source ID: 85034060389

Research output: Contribution to journalArticleScientificpeer-review

Gammaproteobacterial methanotrophs dominate methanotrophy in aerobic and anaerobic layers of boreal lake waters

Small oxygen-stratified humic lakes of the boreal zone are important sources of methane to the atmosphere. Although stable isotope profiling has indicated that a substantial part of methane is already oxidized in the anaerobic water layers in these lakes, the contributions of aerobic and anaerobic methanotrophs in the process are unknown. We used next-generation sequencing of mcrA and 16S rRNA genes to characterize the microbial communities in the water columns of 2 boreal lakes in Finland, Lake Alinen-Mustajärvi and Lake Mekkojärvi, and complemented this with a shotgun metagenomic analysis from Alinen-Mustajärvi and an analysis of pmoA genes and 16S rRNA, mcrA, and pmoA transcripts from Mekkojärvi. Furthermore, we tested the effect of various electron acceptors and light on methane oxidation (13C-CH4 labeling) in incubations of water samples collected from the lakes. Aerobic gammaproteobacterial methanotrophs (order Methylococcales) exclusively dominated the methanotrophic community both above and below the oxycline in the lakes. A novel lineage within Methylococcales, Candidatus Methyloumidiphilus alinensis, defined here for the first time, dominated in Alinen-Mustajärvi, while methanotrophs belonging to Methylobacter were more abundant in Mekkojärvi. Light enhanced methane oxidation in the anoxic water layer, while alternative electron acceptors (SO42-, Fe3+, Mn4+, and anthraquinone-2,6-disulfonate), except for NO3-, suppressed the process. Our results suggest that oxygenic photosynthesis potentially fuels methanotrophy below the aerobic water layers in methane-rich boreal lakes. Furthermore, incubation results, together with the detection of denitrification genes from metagenome-assembled genomes of gammaproteobacterial methanotrophs, imply that boreal lake methanotrophs may couple methane oxidation with NOx- reduction in hypoxic conditions.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, Univ Jyvaskyla, University of Jyvaskyla, Dept Biol & Environm Sci, Nanosci Ctr, University of Jyväskylä, University of Eastern Finland
Contributors: Rissanen, A. J., Saarenheimo, J., Tiirola, M. A., Peura, S., Aalto, S. L., Karvinen, A., Nykänen, H.
Number of pages: 20
Pages: 257-276
Publication date: 2018
Peer-reviewed: Yes

Publication information

Journal: Aquatic Microbial Ecology
Volume: 81
Issue number: 3
ISSN (Print): 0948-3055
Ratings: 
  • Scopus rating (2018): CiteScore 2.26 SJR 0.944 SNIP 0.704
Original language: English

Research output: Contribution to journalArticleScientificpeer-review

High resolution E-jet printed temperature sensor on artificial skin

Skin-conformable electronics research field has grown rapidly during the recent years. Body monitoring systems are shrinking in size and integrating more seamlessly with the human skin. To make these monitoring systems feasible options, new suitable materials and manufacturing processes needs to be studied. This paper presents materials and a simple fabrication process for skin-conformable, E-jet printed silver temperature sensors. Utilizing printing processes and biodegradable substrate materials, the skin-conformable electronics may become attractive for disposable systems by decreasing the manufacturing costs and reducing the amount of waste materials. In this study, the temperature sensors are fabricated with E-jet printed silver nanoparticle ink and the printing is done on a bacterial nanocellulose substrate. During the characterization, the silver temperature sensors were able to reach more than 0.06 % resistance change per degree Celsius sensitivity and they exhibited positive temperature dependence.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electronics and Communications Engineering, Chemistry and Bioengineering, Research group: Bio- and Circular Economy, Research group: Laboratory for Future Electronics
Contributors: Vuorinen, T., Laurila, M. M., Mangayil, R., Karp, M., Mäntysalo, M.
Number of pages: 4
Pages: 839-842
Publication date: 2018

Host publication information

Title of host publication: EMBEC and NBC 2017 - Joint Conference of the European Medical and Biological Engineering Conference EMBEC 2017 and the Nordic-Baltic Conference on Biomedical Engineering and Medical Physics, NBC 2017
Publisher: Springer Verlag
ISBN (Print): 9789811051210

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: Bacterial nanocellulose, E-jet, Printed electronics, Temperature sensor
Electronic versions: 

Bibliographical note

jufoid=58152

Source: Scopus
Source ID: 85021718176

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Identification of feasible pathway information for c-di-GMP binding proteins in cellulose production

In this paper, we utilize a machine learning approach to identify the significant pathways for c-di-GMP signaling proteins. The dataset involves gene counts from 12 pathways and 5 essential c-di-GMP binding domains for 1024 bacterial genomes. Two novel approaches, Least absolute shrinkage and selection operator (Lasso) and Random forests, have been applied for analyzing and modeling the dataset. Both approaches show that bacterial chemotaxis is the most essential pathway for c-di-GMP encoding domains. Though popular for feature selection, the strong regularization of Lasso method fails to associate any pathway to MshE domain. Results from the analysis may help to understand and emphasis to the supporting pathways involved in bacterial cellulose production. These findings demonstrate the need for a chassis to restrict the behavior or functionality by deactivating the selective pathways in cellulose production.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Faculty of Biomedical Sciences and Engineering, Research group: Computational Systems Biology, Chemistry and Bioengineering, BioMediTech
Contributors: Hassan, S. S., Mangayil, R., Aho, T., Yli-Harja, O., Karp, M.
Number of pages: 4
Pages: 667-670
Publication date: 2018

Host publication information

Title of host publication: EMBEC and NBC 2017 - Joint Conference of the European Medical and Biological Engineering Conference EMBEC 2017 and the Nordic-Baltic Conference on Biomedical Engineering and Medical Physics, NBC 2017
Publisher: Springer Verlag
ISBN (Print): 9789811051210

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: Cyclic di-guanosine monophosphate, Metabolic pathways, Random forests, Regularized logistic regression

Bibliographical note

jufoid=58152

Source: Scopus
Source ID: 85021754208

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Light Robots: Bridging the Gap between Microrobotics and Photomechanics in Soft Materials

For decades, roboticists have focused their efforts on rigid systems that enable programmable, automated action, and sophisticated control with maximal movement precision and speed. Meanwhile, material scientists have sought compounds and fabrication strategies to devise polymeric actuators that are small, soft, adaptive, and stimuli-responsive. Merging these two fields has given birth to a new class of devices-soft microrobots that, by combining concepts from microrobotics and stimuli-responsive materials research, provide several advantages in a miniature form: external, remotely controllable power supply, adaptive motion, and human-friendly interaction, with device design and action often inspired by biological systems. Herein, recent progress in soft microrobotics is highlighted based on light-responsive liquid-crystal elastomers and polymer networks, focusing on photomobile devices such as walkers, swimmers, and mechanical oscillators, which may ultimately lead to flying microrobots. Finally, self-regulated actuation is proposed as a new pathway toward fully autonomous, intelligent light robots of the future.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, University of Warsaw, University of Florence
Contributors: Zeng, H., Wasylczyk, P., Wiersma, D. S., Priimagi, A.
Publication date: 2018
Peer-reviewed: Yes

Publication information

Journal: Advanced Materials
Volume: 30
Issue number: 24
Article number: 1703554
ISSN (Print): 0935-9648
Ratings: 
  • Scopus rating (2018): CiteScore 23.77 SJR 10.108 SNIP 3.67
Original language: English
ASJC Scopus subject areas: Materials Science(all), Mechanics of Materials, Mechanical Engineering
Keywords: Actuators, Liquid crystals, Microrobots, Photomobile, Soft robots
Electronic versions: 
Source: Scopus
Source ID: 85031898351

Research output: Contribution to journalArticleScientificpeer-review

On the molecular optical nonlinearity of halogen-bond-forming azobenzenes

We study hyper-Rayleigh scattering and computed molecular hyperpolarizability in a series of azobenzene chromophores in chloroform and dimethylformamide as solvents. The chromophores form halogen or hydrogen bonds of varying strength with dimethylformamide molecules, differently from what is expected for chloroform. We show that hyperpolarizability is unaffected or sligthly lower with the azobenzene forming the strongest halogen bond. Solid supramolecular polymers with the same chromophores have previously demonstrated clearly higher second-order nonlinear responses when a halogen-bond-accepting polymer is used, the larger increase being associated with the stronger halogen bond. The present study proves that the higher optical nonlinearity in polymers lies in the better ordering of the chromophores instead of changes in molecular hyperpolarizability, highlighting the unique properties of halogen bonding in supramolecular chemistry.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Photonics, Research group: Nonlinear Optics, Research group: Chemistry & Advanced Materials, Claude Bernard-University, Università degli Studi di Milano, Politecnico di Milano
Contributors: Virkki, M., Maurice, A., Forni, A., Sironi, M., Dichiarante, V., Brevet, P. F., Metrangolo, P., Kauranen, M., Priimagi, A.
Number of pages: 8
Pages: 28810-28817
Publication date: 2018
Peer-reviewed: Yes

Publication information

Journal: Physical Chemistry Chemical Physics
Volume: 20
Issue number: 45
ISSN (Print): 1463-9076
Ratings: 
  • Scopus rating (2018): CiteScore 3.69 SJR 1.31 SNIP 0.981
Original language: English
ASJC Scopus subject areas: Physics and Astronomy(all), Physical and Theoretical Chemistry
Source: Scopus
Source ID: 85056802102

Research output: Contribution to journalArticleScientificpeer-review

Pathwalue: Pathways with value

This work proposes a tool called PathWalue, that aims to identify commercially interesting reaction routes for bio-production. PathWalue evaluates large sets of pathways using stoichiometric data, pathway properties such as compounds involved and estimates of market information. The public databases Rhea, ChEBI and IntEnz were utilized in this work for reaction, compound and enzyme data, respectively. Data were handled using Python whereas the PathWalue tool was implemented as a JavaScript-based web application. The tool generates, filters and evaluates biochemical pathways. The functioning of the framework was assessed by querying pathways for ethanol and isoprene production and measuring the similarity of the generated pathways to known reference pathways. PathWalue is freely available at http://www.tut.fi/ pathw/.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy
Contributors: Losoi, P., Aho, T.
Number of pages: 4
Pages: 583-586
Publication date: 2018

Host publication information

Title of host publication: EMBEC and NBC 2017 - Joint Conference of the European Medical and Biological Engineering Conference EMBEC 2017 and the Nordic-Baltic Conference on Biomedical Engineering and Medical Physics, NBC 2017
Publisher: Springer Verlag
ISBN (Print): 9789811051210

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: Commercial interest, Pathway identification, Reaction networks

Bibliographical note

jufoid=58152
INT=keb,"Losoi, Pauli"

Source: Scopus
Source ID: 85021772763

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Photoinduced Charge Separation in Semiconductor-Quantum-Dot/Organic-Molecule Hybrids

Semiconductor colloidal quantum dot/organic molecule nanohybrids are gaining momentum due to the relative ease with which an efficient photoinduced charge transfer in the desired direction can be achieved between the dot and the molecule. At the same time analysis of the experimental studies of such systems, and in particular transient absorption spectroscopy data, is a challenging task because of the statistical nature of hybrid formation and the complex kinetics of the photoreactions. This Minireview aims to find common ground for comparing the photoinduced charge-separation reactions in quantum dot/organic molecule hybrids. It also discusses a common set of parameters which would help to compare different quantum dot/molecule hybrids as well as progress in developing design principles to achieve controllable photoinduced charge separation in such hybrids.

General information

Publication status: Published
MoE publication type: A2 Review article in a scientific journal
Organisations: Research group: Chemistry & Advanced Materials, Chemistry and Bioengineering
Contributors: Tkachenko, N.
Number of pages: 9
Pages: 112-120
Publication date: 2018
Peer-reviewed: Yes
Early online date: 14 Nov 2017

Publication information

Journal: ChemPhotoChem
Volume: 2
Issue number: 3
ISSN (Print): 2367-0932
Original language: English

Research output: Contribution to journalReview ArticleScientificpeer-review

Programming Photoresponse in Liquid Crystal Polymer Actuators with Laser Projector

A versatile, laser-projector-based method is demonstrated for programming alignment patterns into monolithic films of liquid crystal polymer networks. Complex images can be photopatterned into the polymer films with sub-100 μm resolution, using relatively short exposure times. The method is further used to devise both photochemically and photothermally driven actuators that can undergo distinct light-induced shape changes, dictated by the programmed alignment patterns. Deformation modes such as buckling and coiling, as well as miniature robotic devices such as a gripper and a light-responsive octopod, are demonstrated. The reported technique enables easy and cost-effective programmable actuation with relatively high throughput, thus significantly facilitating the design and realization of functional soft robotic actuators.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, University of Warsaw
Contributors: Wani, O. M., Zeng, H., Wasylczyk, P., Priimagi, A.
Publication date: 2018
Peer-reviewed: Yes
Early online date: 2017

Publication information

Journal: Advanced Optical Materials
Volume: 6
Issue number: 1
Article number: 1700949
ISSN (Print): 2195-1071
Ratings: 
  • Scopus rating (2018): CiteScore 7.36 SJR 2.711 SNIP 1.58
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Atomic and Molecular Physics, and Optics
Keywords: Azobenzene, Laser projectors, Liquid crystal, Patterning, Photoactuation, Photoalignment
Electronic versions: 
Source: Scopus
Source ID: 85037631675

Research output: Contribution to journalArticleScientificpeer-review

Sediment diffusion method improves wastewater nitrogen removal in the receiving lake sediments

Sediment microbes have a great potential to transform reactive N to harmless N2, thus decreasing wastewater nitrogen load into aquatic ecosystems. Here, we examined if spatial allocation of the wastewater discharge by a specially constructed sediment diffuser pipe system enhanced the microbial nitrate reduction processes. Full-scale experiments were set on two Finnish lake sites, Keuruu and Petäjävesi, and effects on the nitrate removal processes were studied using the stable isotope pairing technique. All nitrate reduction rates followed nitrate concentrations, being highest at the wastewater-influenced sampling points. Complete denitrification with N2 as an end-product was the main nitrate reduction process, indicating that the high nitrate and organic matter concentrations of wastewater did not promote nitrous oxide (N2O) production (truncated denitrification) or ammonification (dissimilatory nitrate reduction to ammonium; DNRA). Using 3D simulation, we demonstrated that the sediment diffusion method enhanced the contact time and amount of wastewater near the sediment surface especially in spring and in autumn, altering organic matter concentration and oxygen levels, and increasing the denitrification capacity of the sediment. We estimated that natural denitrification potentially removed 3–10% of discharged wastewater nitrate in the 33 ha study area of Keuruu, and the sediment diffusion method increased this areal denitrification capacity on average 45%. Overall, our results indicate that sediment diffusion method can supplement wastewater treatment plant (WWTP) nitrate removal without enhancing alternative harmful processes.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, University of Jyväskylä, Univ Jyvaskyla, University of Jyvaskyla, Dept Biol & Environm Sci, Nanosci Ctr, Univ Jyvaskyla, Dept Biomed & Environm Sci
Contributors: Aalto, S. L., Saarenheimo, J., Ropponen, J., Juntunen, J., Rissanen, A. J., Tiirola, M.
Pages: 312-322
Publication date: 2018
Peer-reviewed: Yes

Publication information

Journal: Water Research
Volume: 138
ISSN (Print): 0043-1354
Ratings: 
  • Scopus rating (2018): CiteScore 8.55 SJR 2.721 SNIP 2.426
Original language: English

Research output: Contribution to journalArticleScientificpeer-review

Simultaneous removal of tetrathionate and copper from simulated acidic mining water in bioelectrochemical and electrochemical systems

This study demonstrates (bio)electrochemical tetrathionate (S4O6 2 −) degradation with simultaneous elemental copper recovery from simulated acidic mining water. The effect of applied external voltage on anodic tetrathionate removal, cathodic copper removal and current density was studied using two-chamber flow-through bioelectrochemical (MEC) and abiotic electrochemical (EC) systems. At low applied cell voltages (≤ 0.5 V), the highest tetrathionate removal rate (150–170 mg L− 1 d− 1) and average current density (15–30 mA m− 2) was obtained with MEC. At applied external voltages above 0.75 V, abiotic EC provided the highest average current density (410–3600 mA m− 2). In bioelectrochemical systems, the current generation likely proceeds via intermediary reaction products (sulfide and/or thiosulfate), while in electrochemical system tetrathionate is oxidized directly on the electrode. The copper removal rates remained low (< 10 mg L− 1 d− 1) in all systems at applied cell voltages below 0.5 V, but increased up to a maximum of 440 mg L− 1 d− 1 in MEC and to 450 mg L− 1 d− 1 in EC at applied cell voltage of 1.5 V. After seven days of operation at applied cell voltage of 1.5 V, copper removal efficiency was 99.9% in both MEC and EC and the average tetrathionate removal rates were 160 mg L− 1 d− 1 and 190 mg L− 1 d− 1, respectively. This study shows that by applying external voltage, tetrathionate and copper can be efficiently removed from acidic waters with bioelectrochemical and electrochemical systems.

General information

Publication status: Unpublished
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy
Contributors: Sulonen, M. L., Kokko, M. E., Lakaniemi, A., Puhakka, J. A.
Number of pages: 10
Pages: 129-138
Publication date: 2018
Peer-reviewed: Yes
Early online date: Feb 2018

Publication information

Journal: Hydrometallurgy
Volume: 176
ISSN (Print): 0304-386X
Ratings: 
  • Scopus rating (2018): CiteScore 4 SJR 1.014 SNIP 1.817
Original language: English
ASJC Scopus subject areas: Industrial and Manufacturing Engineering, Metals and Alloys, Materials Chemistry
Keywords: Bioelectrochemical system, Copper removal, Electrochemical system, Reduced inorganic sulfur compound, Tetrathionate
Source: Scopus
Source ID: 85041488580

Research output: Contribution to journalArticleScientificpeer-review

Stable blue phase polymeric Langmuir-Schaefer films based on unsymmetrical hydroxyalkadiynyl N-arylcarbamate derivatives

Unsymmetrical diynes containing N-arylcarbamate groups in the hydrophobic part and hydroxymethylene groups in the hydrophilic part of the molecules were synthesized and studied. The Langmuir monolayer formation process was followed by Brewster angle microscopy (BAM). The Langmuir-Schaefer monolayer films, transferred on solid substrates (quartz or Si), were investigated by absorption spectroscopy and atomic force microscopy (AFM). Four substances had 2 methylene groups in the hydrophilic part of the molecule (n) and 4 or 5 of these groups in the hydrophobic part (m). At the same time the aryl substituent had a hydrogen atom or a MeO group in the p-position of the benzene ring. After 20 min of UV irradiation the initially colorless monomeric films of all four compounds turned into stable blue phase polymeric films. The blue phase is unusual for alcoholic diacetylene derivatives. The BAM and AFM measurements demonstrated higher homogeneity of the films with a MeO group in the aryl substituent in comparison to the molecules with a hydrogen atom. The reasons for these different structural organizations as well as potential applications of stable blue phase polydiacetylene thin films are discussed.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, A. M. Prokhorov General Physics Institute, Russian Academy of Sciences, Åbo Akademi University, St. Petersburg State University, Russian Academy of Science
Contributors: Alekseev, A., Ihalainen, P., Ivanov, A., Domnin, I., Rosqvist, E., Lemmetyinen, H., Vuorimaa-Laukkanen, E., Peltonen, J., Vyaz'min, S.
Number of pages: 11
Pages: 108-118
Publication date: 2018
Peer-reviewed: Yes
Early online date: 10 Oct 2017

Publication information

Journal: Thin Solid Films
Volume: 645
ISSN (Print): 0040-6090
Ratings: 
  • Scopus rating (2018): CiteScore 1.91 SJR 0.531 SNIP 0.815
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Surfaces and Interfaces, Surfaces, Coatings and Films, Metals and Alloys, Materials Chemistry
Keywords: Absorption spectroscopy, Blue phase polydiacetylenes, Brewster angle microscopy, Langmuir-Schaefer film, Photopolymerization

Bibliographical note

EXT="Alekseev, Alexander"

Source: Scopus
Source ID: 85032302551

Research output: Contribution to journalArticleScientificpeer-review

Supramolecular design principles for efficient photoresponsive polymer-azobenzene complexes

Noncovalent binding of azobenzenes to polymers allows harnessing light-induced molecular-level motions (photoisomerization) for inducing macroscopic effects, including photocontrol over molecular alignment and self-assembly of block copolymer nanostructures, and photoinduced surface patterning of polymeric thin films. In the last 10 years, a growing body of literature has proven the utility of supramolecular materials design for establishing structure-property-function guidelines for photoresponsive azobenzene-based polymeric materials. In general, the bond type and strength, engineered by the choice of the polymer and the azobenzene, influence the photophysical properties and the optical response of the material system. Herein, we review this progress, and critically assess the advantages and disadvantages of the three most commonly used supramolecular design strategies: hydrogen, halogen and ionic bonding. The ease and versatility of the design of these photoresponsive materials makes a compelling case for a paradigm shift from covalently-functionalized side-chain polymers to supramolecular polymer-azobenzene complexes.

General information

Publication status: Published
MoE publication type: A2 Review article in a scientific journal
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Département de Chimie, Succ. Centre-Ville
Contributors: Vapaavuori, J., Bazuin, C. G., Priimagi, A.
Number of pages: 21
Pages: 2168-2188
Publication date: 2018
Peer-reviewed: Yes

Publication information

Journal: Journal of Materials Chemistry C
Volume: 6
Issue number: 9
ISSN (Print): 2050-7534
Ratings: 
  • Scopus rating (2018): CiteScore 6.28 SJR 1.885 SNIP 1.321
Original language: English
ASJC Scopus subject areas: Chemistry(all), Materials Chemistry
Electronic versions: 
Source: Scopus
Source ID: 85042792061

Research output: Contribution to journalReview ArticleScientificpeer-review

Techno-economic evaluation of integrating torrefaction with anaerobic digestion

In recent days, the interest on torrefaction is increasing owing to its ability to improve biomass properties to a level of competing with coal. However, its techno-economic feasibility still need to be optimized. Integrating torrefaction with other thermochemical and biochemical processes could be a feasible option to improve the performance of the torrefaction process. In that regard, this study evaluates the techno-economic feasibility of integrating the torrefaction with anaerobic digestion (AD). In addition, new process configurations were studied to identify the possible heat energy recovery options. Technical feasibility was tested through mass and energy balance at each process unit. The economic indicators such as net present value (€), minimum selling price and internal rate on return (%) were used to evaluate the economic performance. At 10 t/h of torrefied biomass pellets production capacity, the estimated bio-methane production from AD was 369 m3/h. The economic evaluation shows that the minimum selling price of the torrefied biomass to reach the breakeven could be reduced from 199 €/t for standalone torrefaction to 185 €/t in case of torrefaction integrated with AD. The sensitivity analysis shows that feedstock and total capital investment were the most sensitive input parameters. This study shows that integrating the torrefaction with AD has better technical and economic feasibility than standalone torrefaction.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy
Contributors: Doddapaneni, T. R. K. C., Praveenkumar, R., Tolvanen, H., Rintala, J., Konttinen, J.
Number of pages: 13
Pages: 272-284
Publication date: 2018
Peer-reviewed: Yes
Early online date: Jan 2018

Publication information

Journal: Applied Energy
Volume: 213
ISSN (Print): 0306-2619
Ratings: 
  • Scopus rating (2018): CiteScore 9.54 SJR 3.455 SNIP 2.616
Original language: English
ASJC Scopus subject areas: Civil and Structural Engineering, Building and Construction, Energy(all), Mechanical Engineering, Management, Monitoring, Policy and Law
Keywords: Energy recovery, Minimum selling price, Process integration, Techno-economic analysis, Torrefaction – anaerobic digestion, Torrefied pellets
Source: Scopus
Source ID: 85041461877

Research output: Contribution to journalArticleScientificpeer-review

Thermophilic versus mesophilic dark fermentation in xylose-fed fluidised bed reactors: Biohydrogen production and active microbial community

Dark fermentative biohydrogen production in a thermophilic, xylose-fed (50 mM) fluidised bed reactor (FBR) was evaluated in the temperature range 55-70 °C with 5-degree increments and compared with a mesophilic FBR operated constantly at 37 °C. A significantly higher (p = 0.05) H2 yield was obtained in the thermophilic FBR, which stabilised at about 1.2 mol H2 mol-1 xylose (36% of the theoretical maximum) at 55 and 70 °C, and at 0.8 mol H2 mol-1 xylose at 60 and 65 °C, compared to the mesophilic FBR (0.5 mol H2 mol-1 xylose). High-throughput sequencing of the reverse-transcribed 16S rRNA, done for the first time on biohydrogen producing reactors, indicated that Thermoanaerobacterium was the prevalent active microorganism in the thermophilic FBR, regardless of the operating temperature. The active microbial community in the mesophilic FBR was mainly composed of Clostridium and Ruminiclostridium at 37 °C. Thermophilic dark fermentation was shown to be suitable for treatment of high temperature, xylose-containing wastewaters, as it resulted in a higher energy output compared to the mesophilic counterpart.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, Natl. University of Ireland, Galway, The James Hutton Institute, Hydraulic and Environmental Engineering (IHE) Inst. for Water Education
Contributors: Dessì, P., Porca, E., Waters, N. R., Lakaniemi, A., Collins, G., Lens, P. N.
Pages: 5473-5485
Publication date: 2018
Peer-reviewed: Yes
Early online date: 2018

Publication information

Journal: International Journal of Hydrogen Energy
Volume: 43
Issue number: 11
ISSN (Print): 0360-3199
Ratings: 
  • Scopus rating (2018): CiteScore 4.16 SJR 1.1 SNIP 1.128
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Fuel Technology, Condensed Matter Physics, Energy Engineering and Power Technology
Keywords: Active community, Biohydrogen, FBR, MiSeq, Thermoanaerobacterium, Thermophilic
Source: Scopus
Source ID: 85042365131

Research output: Contribution to journalArticleScientificpeer-review

Cellulose Nanofiber Alignment Using Evaporation-Induced Droplet-Casting, and Cell Alignment on Aligned Nanocellulose Surfaces

This work investigates droplet-evaporated cellulose nanofiber (CNF) alignment and cell responses on CNF surfaces. Surfaces of unmodified (u-), anionic (a-), and cationic (c-) CNFs were fabricated using an evaporation-induced droplet-casting method and characterized in terms of degree of orientation. Circular variance (CV) values obtained using Cytospectre software to analyze the degree of orientation from AFM images showed a significantly higher degree of orientation on c- and u-CNF surfaces (average CV 0.27 and 0.24, respectively) compared to a-CNF surfaces (average CV 0.76). Quantitative analysis of surface roughness plots obtained from AFM images confirmed the difference between the direction of alignment versus the direction perpendicular to alignment. AFM images as well as observations during droplet evaporation indicated c-CNF alignment parallel to a dry-boundary line during droplet evaporation. Fibroblasts were cultured on the u-, a-, and c-CNF surfaces with or without a fibronectin (FN) coating for 48 h, and the cell response was evaluated in terms of cell viability, proliferation, morphology, and degree of orientation. Cell viability and proliferation were comparable to that on a control surface on the a-CNF and c-CNF surfaces. Although an FN coating slightly enhanced cell growth on the studied surfaces, uncoated a-CNF and c-CNF surfaces were able to support cell growth as well. The results showed cell orientation on aligned c-CNF surfaces, a finding that could be further utilized when guiding the growth of cells. We also showed that the alignment direction of c-CNFs and thus the cell orientation direction can be controlled with a contact-dispensing technique.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Faculty of Biomedical Sciences and Engineering, Automation and Hydraulic Engineering, Research area: Measurement Technology and Process Control, Research group: Micro and Nanosystems Research Group, VTT Technical Research Center of Finland, Biologinkuja 7, 02150 Espoo, Finland.
Contributors: Skogberg, A., Mäki, A., Mettänen, M., Lahtinen, P., Kallio, P.
Number of pages: 18
Pages: 3936–3953
Publication date: 11 Dec 2017
Peer-reviewed: Yes

Publication information

Journal: Biomacromolecules
Volume: 18
Issue number: 12
ISSN (Print): 1525-7797
Ratings: 
  • Scopus rating (2017): CiteScore 5.89 SJR 1.95 SNIP 1.339
Original language: English
Keywords: Journal Article
Source: PubMed
Source ID: 28960956

Research output: Contribution to journalArticleScientificpeer-review

Technology Development and Techno-Economic Analysis of Hydrogen Production by Thermal Decomposition of Methane

The transition to the hydrogen economy has been proposed as a sustainable solution for the simultaneous depletion of fossil fuels and the increase in global energy demand since the 1970s. However, the current fossil fuel-based hydrogen production causes significant CO2 emissions. On the other hand, extensive hydrogen production by water electrolysis powered by renewable electricity requires a remarkable increase in the renewable electricity generation capacity. Therefore, alternative solutions are needed in order to promote the hydrogen economy, develop hydrogen infrastructure, and smoothen the transition to the wide-scale renewable-based hydrogen production in the future.

In this work, thermal decomposition of methane (TDM) was studied as a transition period solution towards the hydrogen economy. In TDM, methane is converted to hydrogen and solid carbon thereby avoiding the direct CO2 emissions. A laboratory-scale test reactor was designed and constructed in this work in order to experimentally study the TDM reaction. The experimental results were combined with mathematical modeling to find a suitable TDM reaction mechanism for reactor design studies. A global reaction mechanism with reaction parameters optimized in this study was found applicable for this purpose.

The TDM product carbon utilization possibilities were evaluated by conducting a market survey. According to the experimental TDM studies in the literature, the product carbon from non-catalytic TDM at temperatures above 1450 K is carbon black. Carbon black is mainly utilized in rubber industry and its market value vary from 500 EUR per tonne to 2,000 EUR per tonne depending on the quality. As a part of the technology development, a design path was outlined to assist the selection of the reaction, reactor, and process parameters for a TDM application. The path was followed in this work when potential industrial-scale technology concepts for hydrogen production by TDM were designed. The economic feasibility of these processes was evaluated and comparison was conducted with two other hydrogen production technologies, i.e., steam methane reforming (SMR) and water electrolysis.

According to the economic analysis, a break-even value for the TDM product carbon was found as 310 EUR per tonne of carbon in the current market situation and 280 EUR per tonne of carbon in a potential market situation in 2030 above which the hydrogen production by TDM would be economically feasible in comparison with SMR. The CO2 emissions from the hydrogen production by TDM were considerably lower than in SMR. Electrolysis could provide an economical option for the production of CO2 -free hydrogen when it is powered by inexpensive renewable electricity, but its availability is expected to remain limited in the near future. By contrast, the feedstock availability through the existing natural gas network provides a possibility for demand-driven hydrogen production by TDM. Thus, the most suitable application for TDM was identified in this work as small or medium industrial scale on-site hydrogen production, which minimizes hydrogen transportation costs. The TDM technology implementation could be further advanced by creating a sufficiently large market for the product carbon and tightening the CO2 emission regulation.

General information

Publication status: Published
MoE publication type: G5 Doctoral dissertation (article)
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy
Contributors: Keipi, T.
Number of pages: 68
Publication date: 8 Dec 2017

Publication information

Publisher: Tampere University of Technology
ISBN (Print): 978-952-15-4057-8
ISBN (Electronic): 978-952-15-4069-1
Original language: English

Publication series

Name: Tampere University of Technology. Publication
Volume: 1519
ISSN (Print): 1459-2045

Research output: Book/ReportDoctoral thesisCollection of Articles

Time-Resolved Fluorescence Spectroscopy Reveals Fine Structure and Dynamics of Poly(l-lysine) and Polyethylenimine Based DNA Polyplexes

Structural dynamics of the polyethylenimine-DNA and poly(l-lysine)-DNA complexes (polyplexes) was studied by steady-state and time-resolved fluorescence spectroscopy using the fluorescence resonance energy transfer (FRET) technique. During the formation of the DNA polyplexes, the negative phosphate groups (P) of DNA are bound by the positive amine groups (N) of the polymer. At N/P ratio 2, nearly all of the DNA's P groups are bound by the polymer N groups: These complexes form the core of the polyplexes. The excess polymer, added to this system to increase the N/P ratio to the values giving efficient gene delivery, forms a positively charged shell around the core polyplex. We investigated whether the exchange between the core and shell regions of PEI and PLL polyplexes takes place. Our results demonstrated a clear difference between the two studied polymers. Shell PEI can replace PEIs previously attached to DNA in the polyplex core, while PLL cannot. Such a dynamic structure of PEI polyplexes compared to a more static one found for PLL polyplexes partially explains the observed difference in the DNA transfection efficiency of these polyplexes. Moreover, the time-resolved fluorescence spectroscopy revealed additional details on the structure of PLL polyplexes: In between the core and shell, there is an intermediate layer where both core and shell PLLs or their parts overlap.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Centre for Drug Research, University of Helsinki, Ita-Suomen yliopisto, Universita degli Studi di Padova, Italy
Contributors: Lisitsyna, E. S., Ketola, T., Morin-Picardat, E., Liang, H., Hanzlíková, M., Urtti, A., Yliperttula, M., Vuorimaa-Laukkanen, E.
Number of pages: 11
Pages: 10782-10792
Publication date: 7 Dec 2017
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry B
Volume: 121
Issue number: 48
ISSN (Print): 1520-6106
Ratings: 
  • Scopus rating (2017): CiteScore 3.13 SJR 1.331 SNIP 0.996
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Surfaces, Coatings and Films, Materials Chemistry
Source: Scopus
Source ID: 85037731381

Research output: Contribution to journalArticleScientificpeer-review

Photodynamic self–disinfecting surface using pyridinium phthalocyanine

We have synthesized novel phthalocyanine with four pyridyl substituents connected to α-phthalo-positions via direct C-C bond. The Zn complex and tetracationic derivatives of phthalocyanine were also synthesized and the dyes were impregnated into filter paper to prepare photoactive antimicrobial surface. The photodynamic antimicrobial efficacy of the dyed paper samples was evaluated by a simple and fast setup using bioluminescent microbes. Escherichia coli and Acinetobacter baylyi ADP1 strains carrying bacterial luciferase genes were used in the screening experiment. The most efficient compound, tetracationic zinc derivative 8, was investigated further. The compound was highly water soluble, had high molar absorptivity and exhibited good adhesion to the filter paper without leaching into the solution. The singlet oxygen quantum yield of tetracationic zinc derivative 8 in water was found out to be 30 ± 20%. According to the cell viability assay test performed on E. coli wild type in solution, the molecule had similar or better photo toxicity as the reference photosensitizer, tetrakis (1-methyl-pyridinium-4-yl)porphyrin (TMPyP). Antimicrobial efficacy of the dye 8 on photoactive surface was studied by live cell assessment through colony forming unit (CFU) counting. The colored surface demonstrated 3 log reduction in CFU against E. coli and A. baylyi ADP1 just after 1 h of illumination with the white light of low intensity.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, Institut für Physik
Contributors: George, L., Müller, A., Röder, B., Santala, V., Efimov, A.
Number of pages: 9
Pages: 334-342
Publication date: 1 Dec 2017
Peer-reviewed: Yes

Publication information

Journal: Dyes and Pigments
Volume: 147
ISSN (Print): 0143-7208
Ratings: 
  • Scopus rating (2017): CiteScore 3.59 SJR 0.819 SNIP 1.005
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Process Chemistry and Technology
Keywords: Antimicrobial, Photodynamic antimicrobial chemotherapy, Pyridinium phthalocyanine, Self-disinfecting surface, Singlet oxygen
Source: Scopus
Source ID: 85027896139

Research output: Contribution to journalArticleScientificpeer-review

Comparison of Scenedesmus acuminatus and Chlorella vulgaris cultivation in liquid digestates from anaerobic digestion of pulp and paper industry and municipal wastewater treatment sludge

Two microalgae, Chlorella vulgaris and Scenedesmus acuminatus, were batch cultivated separately in two types of diluted liquid digestates. The first digestate (ADPP) was obtained from a mesophilic laboratory digester treating biosludge from a pulp and paper industry wastewater treatment plant. The second digestate (ADMW) was collected from a full-scale mesophilic anaerobic digester treating-mixed municipal wastewater treatment sludge. The highest biomass production (as volatile suspended solids, VSS), 8.2–9.4 g L−1, was obtained with S. acuminatus in ADPP. C. vulgaris in ADMW had the lowest biomass production, reaching 2.0 g L−1. Both microalgae removed ammonium efficiently from ADPP (99.9% removal) while the final ammonium removal efficiencies from ADMW with S. acuminatus and C. vulgaris were only 44.0 and 23.8%, respectively. The phosphate removal efficiencies from both ADPP and ADMW were higher than 96.9% with both microalgae. The highest carbohydrate content (60.5%) was obtained with S. acuminatus cultivated in ADPP. Scenedesmus acuminatus in ADPP showed one of the highest biomass production yields that have been reported for microalgae in real wastewater-derived nutrient sources. Consequently, this combination is promising for developing biorefinery and biofuel applications in the pulp and paper industry.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Bio- and Circular Economy, Chemistry and Bioengineering
Contributors: Tao, R., Kinnunen, V., Praveenkumar, R., Lakaniemi, A., Rintala, J. A.
Number of pages: 12
Pages: 2845–2856
Publication date: Dec 2017
Peer-reviewed: Yes

Publication information

Journal: Journal of Applied Phycology
Volume: 29
Issue number: 6
ISSN (Print): 0921-8971
Ratings: 
  • Scopus rating (2017): CiteScore 2.59 SJR 0.784 SNIP 1.022
Original language: English
ASJC Scopus subject areas: Aquatic Science, Plant Science
Keywords: Biorefinery, Chlorophyceae, Digestate, High biomass yield, Microalgae, Nutrient removal
Source: Scopus
Source ID: 85020258442

Research output: Contribution to journalArticleScientificpeer-review

Carbazole-based small molecule electron donors: Syntheses, characterization, and material properties

Efficient synthetic methods for carbazole-based small molecule electron donors with donor–acceptor (D–A) and A–D–A type structures were developed. In order to study the relation between chemical structures and material properties, the prepared compounds were characterized in detail using absorption spectroscopy, differential pulse voltammetry, and computational methods. In addition, symmetrical A–D–A type compounds were tested as an active layer component in bulk heterojunction based organic solar cell (OSC) devices with conventional structure. The results show that the two compound types have many similar properties. However, the extended molecular structure of A–D–A type compounds offer better film forming properties and higher molar absorption coefficients compared with the D–A type materials. Furthermore, the attachment of fluoro substituents in the A units has a positive effect on all solar cell device parameters. Moreover, the computational studies revealed that the molecular structures are twisted between the central carbazole D unit and π-bridge which may result in inefficient intramolecular charge transfer and, also, relatively limited short-circuit currents in OSC devices.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Supramolecular photochemistry, Research group: Chemistry & Advanced Materials, Research Unit of Sustainable Chemistry, IMEC PV Department
Contributors: Sippola, R. J., Hadipour, A., Kastinen, T., Vivo, P., Hukka, T. I., Aernouts, T., Heiskanen, J. P.
Number of pages: 10
Pages: 79-88
Publication date: 8 Nov 2017
Peer-reviewed: Yes
Early online date: 8 Nov 2017

Publication information

Journal: Dyes and Pigments
Volume: 150
Article number: j.dyepig.2017.11.014
ISSN (Print): 0143-7208
Ratings: 
  • Scopus rating (2017): CiteScore 3.59 SJR 0.819 SNIP 1.005
Original language: English
ASJC Scopus subject areas: Chemistry(all), Energy(all)
Keywords: Absorption, DFT, Electron donor, Organic solar cell, Suzuki-Miyaura, Synthesis

Research output: Contribution to journalArticleScientificpeer-review

Multimodal Nonlinear Optical Imaging for Sensitive Detection of Multiple Pharmaceutical Solid-State Forms and Surface Transformations

Two nonlinear imaging modalities, coherent anti-Stokes Raman scattering (CARS) and sum-frequency generation (SFG), were successfully combined for sensitive multimodal imaging of multiple solid-state forms and their changes on drug tablet surfaces. Two imaging approaches were used and compared: (i) hyperspectral CARS combined with principal component analysis (PCA) and SFG imaging and (ii) simultaneous narrowband CARS and SFG imaging. Three different solid-state forms of indomethacin-the crystalline gamma and alpha forms, as well as the amorphous form-were clearly distinguished using both approaches. Simultaneous narrowband CARS and SFG imaging was faster, but hyperspectral CARS and SFG imaging has the potential to be applied to a wider variety of more complex samples. These methodologies were further used to follow crystallization of indomethacin on tablet surfaces under two storage conditions: 30 degrees C/23% RH and 30 degrees C/75% RH. Imaging with (sub)micron resolution showed that the approach allowed detection of very early stage surface crystallization. The surfaces progressively crystallized to predominantly (but not exclusively) the gamma form at lower humidity and the alpha form at higher humidity. Overall, this study suggests that multimodal nonlinear imaging is a highly sensitive, solid-state (and chemically) specific, rapid, and versatile imaging technique for understanding and hence controlling (surface) solid-state forms and their complex changes in pharmaceuticals.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Univ Helsinki, University of Helsinki, Fac Pharm, Div Pharmaceut Chem & Technol, University of Otago, University of Helsinki
Contributors: Novakovic, D., Saarinen, J., Rojalin, T., Antikainen, O., Fraser-Miller, S. J., Laaksonen, T., Peltonen, L., Isomaki, A., Strachan, C. J.
Number of pages: 8
Pages: 11460-11467
Publication date: 7 Nov 2017
Peer-reviewed: Yes

Publication information

Journal: Analytical Chemistry
Volume: 89
Issue number: 21
ISSN (Print): 0003-2700
Ratings: 
  • Scopus rating (2017): CiteScore 6.24 SJR 2.362 SNIP 1.489
Original language: English
Keywords: RAMAN SCATTERING MICROSCOPY, CARS MICROSCOPY, AMORPHOUS INDOMETHACIN, DOSAGE FORMS, TRACE CRYSTALLINITY, T-G, CRYSTALLIZATION, DISSOLUTION, DRUG, POLYMORPHS
Source: WOS
Source ID: 000414887000044

Research output: Contribution to journalArticleScientificpeer-review

Azopolymer photopatterning for directional control of angiogenesis

Understanding cellular behavior in response to microenvironmental stimuli is central to tissue engineering. An increasing number of reports emphasize the high sensitivity of cells to the physical characteristics of the surrounding milieu and in particular, topographical cues. In this work, we investigated the influence of dynamic topographic signal presentation on sprout formation and the possibility to obtain a space–time control over sprouting directionality without growth factors, in order to investigate the contribution of just topography in the angiogenic process. To test our hypothesis, we employed a 3D angiogenesis assay based on the use of spheroids derived from human umbilical vein endothelial cells (HUVECs). We then modulated the in situ presentation of topographical cues during early-stage angiogenesis through real-time photopatterning of an azobenzene-containing polymer, poly (Disperse Red 1 methacrylate) (pDR1m). Pattern inscription on the polymer surface was made using the focused laser of a confocal microscope. We demonstrate that during early-stage angiogenesis, sprouts followed the pattern direction, while spheroid cores acquired a polarized shape. These findings confirmed that sprout directionality was influenced by the photo-inscribed pattern, probably through contact guidance of leader cells, thus validating the proposed platform as a valuable tool for understanding complex processes involved in cell-topography interactions in multicellular systems. Statement of Significance The complex relationship between endothelial cells and the surrounding environment that leads to formation of a newly formed vascular network during tissue repair is currently unknown. We have developed an innovative in vitro platform to study these mechanisms in a space and time controlled fashion simulating what happens during regeneration. In particular, we combine a “smart” surface, namely a polymer film, with a three-dimensional living cell aggregate. The polymer is activated by light through which we can design a path to guide cells toward the formation of a new vessel. Our work lies at the intersection of stimuli-responsive biointerfaces and cell biology and may be particularly inspiring for those interested in designing biomaterial surface related to angiogenesis.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Center for Advanced Biomaterials for Healthcare, Italian Institute of Technology, Dipartimento di Ingegneria Chimica dei Materiali e della Produzione Industriale, ENEA/CREATE/Università Degli Studi Napoli Federico II, Laboratory of Chemistry and Bioengineering
Contributors: Fedele, C., De Gregorio, M., Netti, P. A., Cavalli, S., Attanasio, C.
Number of pages: 9
Pages: 317-325
Publication date: 1 Nov 2017
Peer-reviewed: Yes

Publication information

Journal: Acta Biomaterialia
Volume: 63
ISSN (Print): 1742-7061
Ratings: 
  • Scopus rating (2017): CiteScore 6.97 SJR 1.967 SNIP 1.815
Original language: English
ASJC Scopus subject areas: Biotechnology, Biomaterials, Biochemistry, Biomedical Engineering, Molecular Biology
Keywords: Angiogenesis, Azopolymers, Directional sprouting, Photopatterning, Topographical cues
Source: Scopus
Source ID: 85029628146

Research output: Contribution to journalArticleScientificpeer-review

Effect of hydraulic retention time on continuous electricity production from xylose in up-flow microbial fuel cell

Aerobic wastewater management is energy intensive and thus anaerobic processes are of interest. In this study, a microbial fuel cell was used to produce electricity from xylose which is an important constituent of lignocellulosic waste. Hydraulic retention time (HRT) was optimized for the maximum power density by gradually decreasing the HRT from 3.5 d to 0.17 d. The highest power density (430 mW/m2) was obtained at 1 d HRT. Coulombic efficiency decreased from 30% to 0.6% with HRTs of 3.5 d and 0.17 d, respectively. Microbial community analysis revealed that anode biofilm contained known exoelectrogens, including Geobacter sp. and fermentative organisms were present in both anolyte and the anode biofilm. The peak power densities were obtained at 1-1.7 d HRTs and xylose degraded almost completely even with the lowest HRT of 0.17 d, which demonstrates the efficiency of up-flow MFC for treating synthetic wastewater containing xylose.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, Feng Chia University
Contributors: Haavisto, J. M., Kokko, M. E., Lay, C., Puhakka, J. A.
Pages: 27494-27502
Publication date: 1 Nov 2017
Peer-reviewed: Yes

Publication information

Journal: International Journal of Hydrogen Energy
Volume: 42
ISSN (Print): 0360-3199
Ratings: 
  • Scopus rating (2017): CiteScore 4.1 SJR 1.116 SNIP 1.292
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Fuel Technology, Condensed Matter Physics, Energy Engineering and Power Technology
Keywords: Continuous operation, Hydraulic retention time, Microbial community, Microbial fuel cell, Up-flow, Xylose
URLs: 

Bibliographical note

EXT="Lay, Chyi-How"

Source: Scopus
Source ID: 85019734862

Research output: Contribution to journalArticleScientificpeer-review

Modelling recovery of ammonium from urine by electro-concentration in a 3-chamber cell

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Tampere University of Technology, Chemistry and Bioengineering, University of Queensland
Contributors: Thompson Brewster, E., Jermakka, J., Freguia, S., Batstone, D. J.
Number of pages: 9
Pages: 210-218
Publication date: 1 Nov 2017
Peer-reviewed: Yes

Publication information

Journal: Water Research
Volume: 124
ISSN (Print): 0043-1354
Ratings: 
  • Scopus rating (2017): CiteScore 7.55 SJR 2.601 SNIP 2.388
Original language: English
Keywords: Ammonium bicarbonate, Electro-concentration, Electrochemical model, Nutrient recovery, Physicochemical model, Urine
Source: Scopus
Source ID: 85026353513

Research output: Contribution to journalArticleScientificpeer-review

Nanofibrillar cellulose hydrogels and reconstructed hydrogels as matrices for controlled drug release

Concentrated 3% and 6.5% anionic nanofibrillar cellulose (ANFC) hydrogels were introduced as matrix reservoirs for controlled delivery applications of small molecules and proteins. A further aim was to study how the freeze-drying and subsequent rehydration of ANFC hydrogel affects the rheological properties and drug release of selected model compounds from the reconstructed hydrogels. It was demonstrated that the 3% and 6.5% ANFC hydrogels can be freeze-dried with suitable excipients into highly porous aerogel structures and redispersed back into the hydrogel form without significant change in the rheological properties. Freeze-drying did not affect the drug release properties from redispersed ANFC hydrogels, indicating that these systems could be stored in the dry form and only redispersed when needed. For large molecules, the diffusion coefficients were significantly smaller when higher ANFC fiber content was used, indicating that the amount of ANFC fibers in the hydrogel can be used to control the release rate. The release of small molecules was controlled with the ANFC fiber content only to a moderate extent. The results indicate that ANFC hydrogel can be used for controlled delivery of several types of molecules and that the hydrogel can be successfully freeze-dried and redispersed.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, University of Helsinki, Centre for Drug Research, Universita degli Studi di Padova, Italy
Contributors: Paukkonen, H., Kunnari, M., Laurén, P., Hakkarainen, T., Auvinen, V., Oksanen, T., Koivuniemi, R., Yliperttula, M., Laaksonen, T.
Number of pages: 12
Pages: 269-280
Publication date: 30 Oct 2017
Peer-reviewed: Yes

Publication information

Journal: International Journal of Pharmaceutics
Volume: 532
Issue number: 1
ISSN (Print): 0378-5173
Ratings: 
  • Scopus rating (2017): CiteScore 4.06 SJR 1.172 SNIP 1.302
Original language: English
ASJC Scopus subject areas: Pharmaceutical Science
Keywords: Aerogel, Diffusion, Drug release, Freeze-drying, Hydrogel, Nanofibrillar cellulose, Rheology
Electronic versions: 
URLs: 
Source: Scopus
Source ID: 85029371925

Research output: Contribution to journalArticleScientificpeer-review

A demand-based nutrient utilization approach to urban biogas plant investment based on regional crop fertilization

This study aimed to develop a regional nutrient demand-based approach to assess the potential use of digestate nutrients from a planned biogas plant investment as a part of a regional circular economy concept. The assumed biogas plant is expected to treat urban wastes; biowastes (23,500 t/y) and sewage sludges (120,000 t/y) from the Tampere region, Finland (total population of 500,000). The calculation of the regional nutrient balance was based on the fertilizable crop areas, fertilization regimes and biomass nutrient amounts, with an assumption that livestock manures were primarily utilized in crop production. Subsequently, a Geographic Information System (GIS)-based methodology was applied to evaluate the transportation distances of nutrients from the biogas plant to the closest crop fields. As a result from the presented approach, livestock manure covered 41% and 12% of the phosphorus (P) and soluble nitrogen (N) need of the studied region. There was a residual potential for the regional utilization of biogas plant nutrients, which together with the livestock manure accounted for 50% of P and 15% of soluble-N need. Transportation of nutrients up to 40 km from the biogas plant is necessary if all nearby fields receive the waste-based nutrients, while the distance increased to 66 km if 30% of the local farmers are willing to use the nutrients. The approach presented in this study acts as a tool for planning nutrient cycles, which can be used to sustainably manage the regional nutrient flows when planning a new biogas plant investment.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Natural Resources Institute Finland (Luke)
Contributors: Tampio, E., Lehtonen, E., Kinnunen, V., Mönkäre, T., Ervasti, S., Kettunen, R., Rasi, S., Rintala, J.
Number of pages: 11
Pages: 19-29
Publication date: 15 Oct 2017
Peer-reviewed: Yes

Publication information

Journal: Journal of Cleaner Production
Volume: 164
ISSN (Print): 0959-6526
Ratings: 
  • Scopus rating (2017): CiteScore 5.79 SJR 1.467 SNIP 2.339
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Environmental Science(all), Strategy and Management, Industrial and Manufacturing Engineering
Keywords: Biogas plant, Biowaste, Digestate, Livestock manure, Nutrient recycling, Sewage sludge

Bibliographical note

EXT="Tampio, Elina"

Source: Scopus
Source ID: 85027488845

Research output: Contribution to journalArticleScientificpeer-review

Effect of natural convection and radiation inside of a hollow beam in a standard fire

In the design of steel structures, special attention must be paid on structural fire design in order to ensure a specified safe time period that the structure can withstand the fire without collapse. In the European design rules, the standard practise assumes uniform temperature for steel beam cross sections while the surrounding area is subjected to the so called standard fire. When the ambient temperature field is not uniform (e.g. at beam joint areas) neither will be the beam cross section temperature field. This paper studies the contribution of natural convection and cavity radiation to the temperature field of a hollow beam cross section in the case of non-uniform ambient temperature by using transient CFD-simulations.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, Civil Engineering, Research group: Light-weight structures, Aalborg University
Contributors: Välikangas, T., Pajunen, S., Baczkiewicz, J., Singh, S., Sørensen, K.
Number of pages: 7
Pages: 121-127
Publication date: 27 Sep 2017

Host publication information

Title of host publication: Proceedings of the 58th Conference on Simulation and Modelling (SIMS 58) Reykjavik, Iceland, September 25th – 27th, 2017
Volume: 138
Place of publication: Linköping
Publisher: Linköping University Electronic Press
Editor: Jonsson, M. T.
Article number: 16
ISBN (Electronic): 978-91-7685-417-4

Publication series

Name: Linköping Electronic Conference Proceedings
Publisher: Linköping University Electronic Press
No.: 138
ISSN (Print): 1650-3686
ISSN (Electronic): 1650-3740

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

New Evidence for the Mechanism of Action of a Type-2 Diabetes Drug Using a Magnetic Bead-Based Automated Biosensing Platform

The mechanism of action (MOA) of the first line type-2 diabetes drug metformin remains unclear despite its widespread usage. However, recent evidence suggests that the mitochondrial copper (Cu)-binding action of metformin may contribute toward the drug's MOA. Here, we present a novel biosensing platform for investigating the MOA of metformin using a magnetic microbead-based agglutination assay which has allowed us to demonstrate for the first time the interaction between Cu and metformin at clinically relevant low micromolar concentrations of the drug, thus suggesting a potential pathway of metformin's blood-glucose lowering action. In this assay, cysteine-functionalized magnetic beadswere agglutinated in the presence of Cu due to cysteine's Cu-chelation property. Addition of clinically relevant doses of metformin resulted in disaggregation of Cu-bridged bead-clusters, whereas the effect of adding a closely related but blood-glucose neutral drug propanediimidamide (PDI) showed completely different responses to the clusters. The entire assay was integrated in an automated microfluidics platform with an advanced optical imaging unit by which we investigated these aggregation-disaggregation phenomena in a reliable, automated, and user-friendly fashion with total assay time of 17 min requiring a sample (metformin/PDI) volume of 30 μL. The marked difference of Cu-binding action between the blood-glucose lowering drug metformin and its inactive analogue PDI thus suggests that metformin's distinctive Cu-binding properties may be required for its effect on glucose homeostasis. The novel automated platform demonstrating this novel investigation thus holds the potential to be utilized for investigating significant and sensitive molecular interactions via magnetic bead-based agglutination assay.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Danmarks Tekniske Universitet, DTU Informatik, University of Dundee, Academia Sinica Taiwan
Contributors: Uddin, R., Nur-E-Habiba, N., Rena, G., Hwu, E. T., Boisen, A.
Number of pages: 8
Pages: 1329-1336
Publication date: 22 Sep 2017
Peer-reviewed: Yes

Publication information

Journal: ACS Sensors
Volume: 2
Issue number: 9
ISSN (Print): 1424-8220
Ratings: 
  • Scopus rating (2017): CiteScore 3.23 SJR 0.584 SNIP 1.567
Original language: English
ASJC Scopus subject areas: Bioengineering, Fluid Flow and Transfer Processes, Process Chemistry and Technology, Instrumentation
Keywords: agglutination assay, biosensor, magnetic beads, metformin, molecular interactions, optical imaging, type-2 diabetes

Bibliographical note

INT=keb,"Nur-E-Habiba, N."

Source: Scopus
Source ID: 85029817525

Research output: Contribution to journalArticleScientificpeer-review

Bioelectrochemical Recovery of Energy and Metals from Simulated Mining Waters

Extremely acidic water with high metal concentrations is often produced during mining and processing of sulfidic ores. Sulfur-oxidizing microorganisms contribute significantly to the acidification of the water streams and oxygen depletion by oxidizing reduced inorganic sulfur compounds (RISCs) — which are released to the mining waters during the processing of sulfide minerals — to sulfuric acid. The acidic water continues leaching metals from minerals and the metal concentrations thus further increase.

Certain metals can be recovered from acidic solutions by using them as the electron acceptor at the cathode of an electrochemical system. The metal ions accept electrons from an electrode and deposit on the surface of the electrode in pure elemental form. The electrical current required for the electrodeposition of metals is conventionally drawn from the oxidation of water. However, with the assist of electroactive microorganisms, biodegradable compounds can be used as the source of the required energy. Electroactive microorganisms oxidize a substrate and donate electrons to an anode electrode. The flow of electrons from anode to cathode creates electrical current, which can be utilized in the electrodeposition of the metals. As mining waters do not usually contain organic compounds, RISCs are promising substrates for the recovery of metals from mining waters — they are present in the same stream and can be oxidized at lower potential than water. In addition, with the electrochemical treatment both metals and RISCs could be removed from the water streams simultaneously.

The aim of this work was to use tetrathionate (S4O62-) as the substrate for bioelectrochemical and electrochemical current generation. The possibility to spontaneously produce electricity from tetrathionate was first studied in microbial fuel cells (Paper I). After successful electricity production was obtained, a tetrathionate-fed microbial fuel cell was monitored for over 740 days to determine the long-term stability of such systems (Paper II). The anode potential was then externally adjusted in order to determine the minimum anode potential required for bioelectrochemical and electrochemical tetrathionate degradation (Paper III). Finally, the external voltage required for the simultaneous removal of tetrathionate and copper was determined (Paper IV).

The experiments were conducted using two-chamber flow through reactors at room temperature (22±5 °C) and highly acidic conditions (pH < 2.5). The initial lag-time for electricity production from tetrathionate was relatively long in bioelectrochemical systems (approximately 100 days), but spontaneous electricity production was proven successful with ferric iron as the cathodic electron acceptor. By optimizing the external resistance, the current density was successfully improved from 80 mA m-2 (1000 Ω) to 225 mA m-2 (100 Ω). In the long-term experiment, biofouling or accumulating reaction products were not observed to limit the electricity production even after 740 days of operation. The minimum anode potential for tetrathionate degradation was observed to be 0.3 V vs. Ag/AgCl in the bioelectrochemical systems and 0.5 V in the abiotic electrochemical systems. Higher tetrathionate degradation rates were obtained in the bioelectrochemical systems (>110 mg L-1 d-1) than in the electrochemical systems (<35 mg L-1 d-1). The reaction products of bioelectrochemical tetrathionate degradation were sulfate and elemental sulfur, while in electrochemical systems only sulfate was detected. For the efficient removal of tetrathionate and copper, applied voltage of above 1.0 V was required. The concentrations of tetrathionate and copper were successfully decreased below the limits set for toxicity (0.5 g S4O62- L-1) and mining effluent discharge (0.3 mg Cu2+ L-1).

This study demonstrates for the first time that tetrathionate can be used the substrate for bioelectrochemical current generation. In bioelectrochemical systems with an efficient catholyte, tetrathionate is degraded and electricity is produced spontaneously, but abiotic electrochemical degradation requires external energy. Both bioelectrochemical and electrochemical systems provided higher current densities than a water-oxidizing control reactor when controlling the anode potential or applying external voltage. The simultaneous removal of tetrathionate and copper shows that bioelectrochemical and electrochemical systems are promising alternatives for the treatment of mining waters.

General information

Publication status: Published
MoE publication type: G5 Doctoral dissertation (article)
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy
Contributors: Sulonen, M.
Number of pages: 98
Publication date: 15 Sep 2017

Publication information

Publisher: Tampere University of Technology
ISBN (Print): 978-952-15-3984-8
ISBN (Electronic): 978-952-15-4002-8
Original language: English

Publication series

Name: Tampere University of Technology. Publication
Volume: 1485
ISSN (Electronic): 1459-2045

Research output: Book/ReportDoctoral thesisCollection of Articles

Hole-Transporting Materials for Printable Perovskite Solar Cells

Perovskite solar cells (PSCs) represent undoubtedly the most significant breakthrough in photovoltaic technology since the 1970s, with an increase in their power conversion efficiency from less than 5% to over 22% in just a few years. Hole-transporting materials (HTMs) are an essential building block of PSC architectures. Currently, 2,2’,7,7’-tetrakis-(N,N’-di-p-methoxyphenylamine)-9,9’-spirobifluorene), better known as spiro-OMeTAD, is the most widely-used HTM to obtain high-efficiency devices. However, it is a tremendously expensive material with mediocre hole carrier mobility. To ensure wide-scale application of PSC-based technologies, alternative HTMs are being proposed. Solution-processable HTMs are crucial to develop inexpensive, high-throughput and printable large-area PSCs. In this review, we present the most recent advances in the design and development of different types of HTMs, with a particular focus on mesoscopic PSCs. Finally, we outline possible future research directions for further optimization of the HTMs to achieve low-cost, stable and large-area PSCs.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Supramolecular photochemistry, Research group: Chemistry & Advanced Materials
Contributors: Vivo, P., Salunke, J. K., Priimagi, A.
Publication date: 15 Sep 2017
Peer-reviewed: Yes

Publication information

Journal: Materials
Volume: 10
Issue number: 9
ISSN (Print): 1996-1944
Ratings: 
  • Scopus rating (2017): CiteScore 3.02 SJR 0.732 SNIP 1.285
Original language: English

Research output: Contribution to journalArticleScientificpeer-review

Understanding selenium biogeochemistry in engineered ecosystems: Transformation and analytical methods

Selenium is used extensively in many industries, and it is necessary for human nutrition. On the other hand, it is also toxic at slightly elevated concentrations. With the advent of industrialisation, selenium concentrations in the environment due to anthropogenic activities have increased. Treatment of selenium-laden wastewaters and bioremediation are of increasing importance for counteracting contamination. Developing an effective treatment process requires the identification of all the selenium chemical species and their concentrations in engineered settings. This chapter collates the available techniques for identifying and quantifying various selenium species in gas, liquid, and solid phases, including X-ray absorption spectroscopy, electron microscopy, and liquid/gas chromatography. This chapter also throws light on isotopic fractionation and sequential extraction methods used to study the behaviour of selenium. Prior to the discussion of analytical methods, this chapter discusses selenium mineralogy and biochemistry. Finally, the chapter concludes by discussing potential future analytical techniques that will further improve our understanding of selenium biogeochemistry in engineered bioprocesses.

General information

Publication status: Published
MoE publication type: A3 Part of a book or another research book
Organisations: Chemistry and Bioengineering, UPEM, Hydraulic and Environmental Engineering (IHE) Inst. for Water Education, University of Applied Sciences and Arts Northwestern Switzerland (FHNW), Wageningen University and Research Centre, Laboratoire de Biochimie Théorique
Contributors: Jain, R., Van Hullebusch, E. D., Lenz, M., Farges, F.
Number of pages: 24
Pages: 33-56
Publication date: 2 Sep 2017

Host publication information

Title of host publication: Bioremediation of Selenium Contaminated Wastewater
Publisher: Springer International Publishing
ISBN (Print): 9783319578309
ISBN (Electronic): 9783319578316
ASJC Scopus subject areas: Engineering(all), Chemical Engineering(all), Environmental Science(all), Immunology and Microbiology(all), Chemistry(all)
Keywords: Bioremediation, Elemental speciation, Redox labile elements, Trace elements
Source: Scopus
Source ID: 85034980155

Research output: Chapter in Book/Report/Conference proceedingChapterScientificpeer-review

Comparison of liposomal drug formulations for transdermal iontophoretic drug delivery

This study was aimed to evaluate the in vitro transdermal direct/pulsed current iontophoretic delivery of an amphiphilic model compound from various lipid vesicle-encapsulated formulations compared to free-drug formulation. Conventional, pegylated, ultradeformable liposomes (transfersomes) and ethosomes loaded with a negatively charged drug diclofenac sodium (DS) were prepared and characterized. All the liposomes possessed an average size of ≈ 100–150 nm and negative zeta potential. No changes in colloidal stability were detected after 8 h incubation of any vesicle formulation under constant or pulsed iontophoretic current. DS was released from all the liposome formulations with a similar, limited rate (≈ 50% in 24 h), leading therefore to significantly lower transdermal fluxes across full-thickness porcine skin compared to the respective free drug formulation. From the tested lipid vesicle formulations, the transfersomes resulted in the highest passive flux and the ethosomes in the highest iontophoretic flux under direct constant current treatment. Higher negative surface charge of the vesicle led to better transport efficiency due to the higher mobility of the drug carrier under electric field. Pulsed current iontophoresis had no advantage over constant current treatment in combination with any type of lipid vesicular nanocarriers, in contrast to what has been described earlier with drug-loaded polymeric nanocarriers.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, University of Helsinki, University of Navarra, Division of Pharmaceutical Chemistry and Technology
Contributors: Malinovskaja-Gomez, K., Espuelas, S., Garrido, M. J., Hirvonen, J., Laaksonen, T.
Number of pages: 8
Pages: 294-301
Publication date: 30 Aug 2017
Peer-reviewed: Yes

Publication information

Journal: European Journal of Pharmaceutical Sciences
Volume: 106
ISSN (Print): 0928-0987
Ratings: 
  • Scopus rating (2017): CiteScore 3.81 SJR 1.016 SNIP 1.317
Original language: English
ASJC Scopus subject areas: Pharmaceutical Science
Keywords: Diclofenac sodium, Iontophoresis, Liposome, NSAID delivery, Skin permeation, Transdermal drug delivery
Electronic versions: 
URLs: 
Source: Scopus
Source ID: 85020916069

Research output: Contribution to journalArticleScientificpeer-review

Locomotion of light-driven soft microrobots through a hydrogel via local melting

Soft mobile microrobots whose deformation can be directly controlled by an external field can adapt to move in different environments. This is the case for the light-driven microrobots based on liquid-crystal elastomers (LCEs). Here we show that the soft microrobots can move through an agarose hydrogel by means of light-controlled travelling-wave motions. This is achieved by exploiting the inherent rise of the LCE temperature above the melting temperature of the agarose gel, which facilitates penetration of the microrobot through the hydrogel. The locomotion performance is investigated as a function of the travelling-wave parameters, showing that effective propulsion can be obtained by adapting the generated motion to the specific environmental conditions.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Chemistry and Bioengineering, Max Planck Institute for Intelligent Systems, Max Planck ETH Center for Learning Systems, University of Florence, CNR-INO, University of Stuttgart
Contributors: Palagi, S., Mark, A. G., Melde, K., Qiu, T., Zeng, H., Parmeggiani, C., Martella, D., Wiersma, D. S., Fischer, P.
Publication date: 3 Aug 2017

Host publication information

Title of host publication: International Conference on Manipulation, Automation and Robotics at Small Scales, MARSS 2017 - Proceedings
Publisher: IEEE
ISBN (Electronic): 9781538603468
ASJC Scopus subject areas: Mechanical Engineering, Artificial Intelligence, Control and Optimization
Keywords: Hydrogels, Liquid-crystal elastomers (LCEs), Soft microrobots
Source: Scopus
Source ID: 85030234395

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Effects of different nickel species on autotrophic denitrification driven by thiosulfate in batch tests and a fluidized-bed reactor

Nickel is a common heavy metal and often occurs with nitrate (NO3 ) in effluents from mining and metal-finishing industry. The present study investigates the effects of increasing concentrations (5–200 mg Ni/L) of NiEDTA2− and NiCl2 on autotrophic denitrification with thiosulfate (S2O3 2−) in batch tests and a fluidized-bed reactor (FBR). In batch bioassays, 50 and 100 mg Ni/L of NiEDTA2− only increased the transient accumulation of NO2 , whereas 25–100 mg Ni/L of NiCl2 inhibited denitrification by 9–19%. NO3 and NO2 were completely removed in the FBR at feed NiEDTA2− and NiCl2 concentrations as high as 100 and 200 mg Ni/L, respectively. PCR-DGGE revealed the dominance of Thiobacillus denitrificans and the presence of the sulfate-reducing bacterium Desulfovibrio putealis in the FBR microbial community at all feed nickel concentrations investigated. Nickel mass balance, thermodynamic modeling and solid phase characterization indicated that nickel sulfide, phosphate and oxide precipitated in the FBR during NiCl2 injection.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Industrial Bioengineering and Applied Organic Chemistry, Research group: Bio- and Circular Economy, University of Cassino and Southern Lazio, UPEM, Hydraulic and Environmental Engineering (IHE) Inst. for Water Education
Contributors: Di Capua, F., Milone, I., Lakaniemi, A., Hullebusch, E. D., Lens, P. N., Esposito, G.
Number of pages: 8
Pages: 534-541
Publication date: 1 Aug 2017
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 238
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2017): CiteScore 6.28 SJR 2.029 SNIP 1.823
Original language: English
ASJC Scopus subject areas: Bioengineering, Environmental Engineering, Waste Management and Disposal
Keywords: Autotrophic denitrification, EDTA, Fluidized-bed reactor, Nickel, Thiosulfate

Bibliographical note

INT=keb,"Di Capua, Fransesco"

Source: Scopus
Source ID: 85019042670

Research output: Contribution to journalArticleScientificpeer-review

Nanofibrillar cellulose-alginate hydrogel coated surgical sutures as cell-carrier systems

Hydrogel nanomaterials, especially those that are of non-human and non-animal origins, have great potential in biomedical and pharmaceutical sciences due to their versatility and inherent soft-tissue like properties. With the ability to simulate native tissue function, hydrogels are potentially well suited for cellular therapy applications. In this study, we have fabricated nanofibrillar cellulose-alginate (NFCA) suture coatings as biomedical devices to help overcome some of the limitations related to cellular therapy, such as low cell survivability and distribution out of target tissue. The addition of sodium alginate 8% (w/v) increased the NFCA hydrogel viscosity, storage and loss moduli by slightly under one order of magnitude, thus contributing significantly to coating strength. Confocal microscopy showed nearly 100% cell viability throughout the 2-week incubation period within and on the surface of the coating. Additionally, typical morphologies in the dual cell culture of spheroid forming HepG2 and monolayer type SK-HEP-1 were observed. Twelve out of 14 NFCA coated surgical sutures remained intact during the suturing operation with various mice and rat tissue; however, partial peeling off was observed in 2 of the coated sutures. We conclude that NFCA suture coatings could perform as cell-carrier systems for cellular based therapy and post-surgical treatment.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, University of Helsinki, Aalto University, Ita-Suomen yliopisto, Made Consulting, Centre for Drug Research
Contributors: Laurén, P., Somersalo, P., Pitkänen, I., Lou, Y. R., Urtti, A., Partanen, J., Seppälä, J., Madetoja, M., Laaksonen, T., Mäkitie, A., Yliperttula, M.
Publication date: 1 Aug 2017
Peer-reviewed: Yes

Publication information

Journal: PLoS ONE
Volume: 12
Issue number: 8
Article number: e0183487
ISSN (Print): 1932-6203
Ratings: 
  • Scopus rating (2017): CiteScore 3.01 SJR 1.164 SNIP 1.144
Original language: English
ASJC Scopus subject areas: Medicine(all), Biochemistry, Genetics and Molecular Biology(all), Agricultural and Biological Sciences(all)
Electronic versions: 
Source: Scopus
Source ID: 85028334326

Research output: Contribution to journalArticleScientificpeer-review

Photoresponsive Polymer Hydrogel Coatings that Change Topography

This chapter provides a brief overview of the principles as well as the potential applications of photoresponsive hydrogel films, which change surface topography. It discusses the operating mechanisms that lead to topographical changes. Changes in topography can affect the wettability of a surface, which is an interesting characteristic for making self-cleaning coatings. The chapter also discusses polymer films that are useful for the development of self-cleaning films. It then discusses responsive materials, for cell culturing and microfluidics applications. The chapter further shows that appealing photoresponsive polymer hydrogel coatings that change topography can be fabricated, which holds great promise in a variety of fields ranging from microfluidic devices to biomedical applications. When the structures of the topography are in the micrometer size regime, they influence the wettability of the surface. Two types of wetting can be defined: Wenzel and Cassie-Baxter.

General information

Publication status: Published
MoE publication type: A3 Part of a book or another research book
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials
Contributors: Stumpel, J. E., ter Schiphorst, J., Schenning, A. P. H. J.
Pages: 159-173
Publication date: 21 Jul 2017

Host publication information

Title of host publication: Responsive Polymer Surfaces : Dynamics in Surface Topography
Publisher: Wiley-VCH
Editors: Liu, D., Broer, D.
ISBN (Print): 978-3-527-33869-6
ISBN (Electronic): 9783527690534

Research output: Chapter in Book/Report/Conference proceedingChapterScientificpeer-review

Effect of alkylaminophenols on growth inhibition and apoptosis of bone cancer cells

In this work, we report the anticancer properties of a series of 11 chemically synthesized alkylaminophenols against human osteosarcoma U2OS tumor cell line. Several assays including cytotoxicity, inhibitor kinetic study, cell migration, Annexin-V/PI double staining, reactive oxygen species (ROS) and caspase 3/7 assays were conducted on this cell line. Cytotoxic 2-((3,4-dihydroquinolin-1(2H)-yl)(p-tolyl)methyl)phenol was determined to have an IC50 value of 36.6μM against U2OS cells and it also inhibits the cell growth in time-dependent manner. The potent activity of lead compound against the growth of multiple cell lines, U2OS, MG-65 and HEK-293T, confirms the osteosarcoma cell specific inhibition. Further studies indicated that such compound is an inhibitor of metastatic property of tumor cells and inducing apoptosis agent. The ability of increasing ROS and inducing caspases 3 and 7 further confirm the contribution of programmed cell death in U2OS and HEK-293T cells. Additionally, four compounds based on the 2-(indolin-1-yl(aryl)methyl)-4-nitrophenol core were also identified to be cytotoxic with IC50 values in the 66-88μM range. This work further demonstrates the anticancer properties of phenol derivatives, adding one more entry to the collection of promising chemotherapeutic agents for cancer treatment.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Faculty of Biomedical Sciences and Engineering, Research group: Computational Systems Biology, Chemistry and Bioengineering, Research group: Industrial Bioengineering and Applied Organic Chemistry, Research group: Chemistry & Advanced Materials, BioMediTech, Molecular Signaling Lab, Computational Systems Biology Research Group, BioMediTech and Faculty of Biomedical Sciences and Engineering, Tampere University of Technology, P.O.Box 553, 33101 Tampere, Finland.
Contributors: Doan, P., Nguyen, T., Yli-Harja, O., Candeias, N. R., Kandhavelu, M.
Number of pages: 9
Pages: 208–216
Publication date: 17 Jul 2017
Peer-reviewed: Yes

Publication information

Journal: European Journal of Pharmaceutical Sciences
Volume: 107
ISSN (Print): 0928-0987
Ratings: 
  • Scopus rating (2017): CiteScore 3.81 SJR 1.016 SNIP 1.317
Original language: English
Keywords: Journal Article

Bibliographical note

INT=TUT-BMT, "Nguyen, Tien"

Source: PubMed
Source ID: 28728976

Research output: Contribution to journalArticleScientificpeer-review

Long-Range Observation of Exciplex Formation and Decay Mediated by One-Dimensional Bridges

We report herein unprecedented long-range observation of both formation and decay of the exciplex state in donor (D)-bridge (B)-acceptor (A) linked systems. Zinc porphyrins (ZnP) as a donor were tethered to single-walled carbon nanotube (SWNT) as an acceptor through oligo(p-phenylene)s (ZnP-phn-SWNT) or oligo(p-xylene)s (ZnP-xyn-1-ph1-SWNT) with systematically varied lengths (n = 1-5) to address the issue. Exponential dependencies of rate constants for the exciplex formation (kFEX) and decay (kDEX) on the edge-to-edge separation distance between ZnP and SWNT through the bridges were unambiguously derived from time-resolved spectroscopies. Distance dependencies (i.e., attenuation factor, β) of kFEX and kDEX in ZnP-phn-SWNT were found to be considerably small (β = 0.10 for kFEX and 0.12 Å-1 for kDEX) compared to those for charge separation and recombination (0.2-0.8 Å-1) in D-B-A systems with the same oligo(p-phenylene) bridges. The small β values may be associated with the exciplex state with mixed characters of charge-transfer and excited states. In parallel, the substantially nonconjugated bridge of oligo(p-xylene)s exhibited larger attenuation values (β = 0.12 for kFEX and 0.14 Å-1 for kDEX). These results provide deep insight into the unique photodynamics of electronically strongly coupled D-B-A systems involving exciplex.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Kyoto Women's University
Contributors: Baek, J., Umeyama, T., Stranius, K., Yamada, H., Tkachenko, N. V., Imahori, H.
Number of pages: 10
Pages: 13952-13961
Publication date: 29 Jun 2017
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry C
Volume: 121
Issue number: 25
ISSN (Print): 1932-7447
Ratings: 
  • Scopus rating (2017): CiteScore 4.58 SJR 2.135 SNIP 1.135
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Energy(all), Surfaces, Coatings and Films, Physical and Theoretical Chemistry
Source: Scopus
Source ID: 85022231305

Research output: Contribution to journalArticleScientificpeer-review

Effects of alternative electron acceptors on the activity and community structure of methane-producing and consuming microbes in the sediments of two shallow boreal lakes

The role of anaerobic CH4 oxidation in controlling lake sediment CH4 emissions remains unclear. Therefore, we tested how relevant EAs (SO42-, NO3-, Fe3+, Mn4+, O2) affect CH4 production and oxidation in the sediments of two shallow boreal lakes. The changes induced to microbial communities by the addition of Fe3+ and Mn4+ were studied using next-generation sequencing targeting the 16S rRNA and methyl-coenzyme M reductase (mcrA) genes and mcrA transcripts. Putative anaerobic CH4 oxidizing archaea (ANME-2D) and bacteria (NC 10) were scarce (up to 3.4% and 0.5% of archaeal and bacterial 16S rRNA genes, respectively), likely due to the low environmental stability associated with shallow depths. Consequently, the potential anaerobic CH4 oxidation (0-2.1 nmol g-1dry weight (DW)d-1) was not enhanced by the addition of EAs, nor important in consuming the produced CH4 (0.6-82.5 nmol g-1DWd-1). Instead, the increased EA availability suppressed CH4 production via the outcompetition of methanogens by anaerobically respiring bacteria and via the increased protection of organic matter from microbial degradation induced by Fe3+ and Mn4+. Future studies could particularly assess whether anaerobic CH4 oxidation has any ecological relevance in reducing CH4 emissions from the numerous CH4-emitting shallow lakes in boreal and tundra landscapes.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy
Contributors: Rissanen, A. J., Karvinen, A., Nykänen, H., Peura, S., Tiirola, M., Mäki, A., Kankaala, P.
Publication date: 15 Jun 2017
Peer-reviewed: Yes

Publication information

Journal: FEMS Microbiology Ecology
Volume: 93
Issue number: 7
ISSN (Print): 0168-6496
Ratings: 
  • Scopus rating (2017): CiteScore 3.87 SJR 1.492 SNIP 1.086
Original language: English
Keywords: lake, sediment, methanogenesis, methane oxidation, 16S rRNA, mcrA

Bibliographical note

© FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Source: PubMed
Source ID: 28637304

Research output: Contribution to journalArticleScientificpeer-review

The role of inorganics in modelling of biomass gasification

In this work, a summary of the research carried out about the role of inorganic elements in biomass gasification is presented. The research work has focused on the catalytic effects of alkali and alkaline earth metals in char gasification. The work has included gasification experiments using thermogravimetric analysis (TGA) and fluidized beds as well as modeling techniques. The results of the research presented in this paper indicate that the laboratory measured TGA reactivity numbers and correlations (including the effect of fuel ash inorganics) are possible to be converted to numbers predicting carbon conversion in a large scale fluidized bed gasification reactor. The model, called Carbon Conversion Predictor, is a relatively simple and transparent tool for the comparison of the gasification reactivity of different fuels in fluidized bed gasification.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, Univ Seville, University of Sevilla, Chem & Environm Engn Dept, Bioenergy Grp, Escuela Super Ingenieros, Åbo Akademi University, Process Chemistry Center
Contributors: Konttinen, J., Kramb, J., DeMartini, N., Gomez-Barea, A.
Number of pages: 5
Pages: 443-447
Publication date: 13 Jun 2017

Host publication information

Title of host publication: EUBCE 2017 Online Conference Proceedings
Publisher: ETA-Florence Renewable Energies
Editors: Ek, L., Ernrooth, H., Scarlat, N., Grassi, A., Helm, P.
ISBN (Electronic): 978-88-89407-17-2

Publication series

Name: European biomass conference and exhibition proceedings
Publisher: ETA Florence revewable energies
ISSN (Electronic): 2282-5819

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Self-Regulating Iris Based on Light-Actuated Liquid Crystal Elastomer

The iris, found in many animal species, is a biological tissue that can change the aperture (pupil) size to regulate light transmission into the eye in response to varying illumination conditions. The self-regulation of the eye lies behind its autofocusing ability and large dynamic range, rendering it the ultimate "imaging device" and a continuous source of inspiration in science. In optical imaging devices, adjustable apertures play a vital role as they control the light exposure, the depth of field, and optical aberrations of the systems. Tunable irises demonstrated to date require external control through mechanical actuation, and are not capable of autonomous action in response to changing light intensity without control circuitry. A self-regulating artificial iris would offer new opportunities for device automation and stabilization. Here, this paper reports the first iris-like, liquid crystal elastomer device that can perform automatic shape-adjustment by reacting to the incident light power density. Similar to natural iris, the device closes under increasing light intensity, and upon reaching the minimum pupil size, reduces the light transmission by a factor of seven. The light-responsive materials design, together with photoalignment-based control over the molecular orientation, provides a new approach to automatic, self-regulating optical systems based on soft smart materials.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Warsaw Univ Technol, Warsaw University of Technology, Fac Phys, Opt Div, Department and Clinic of Ophthalmology, Wrocław Medical University, Wrocław, Poland
Contributors: Zeng, H., Wani, O. M., Wasylczyk, P., Kaczmarek, R., Priimägi, A.
Publication date: 7 Jun 2017
Peer-reviewed: Yes

Publication information

Journal: Advanced Materials
ISSN (Print): 0935-9648
Ratings: 
  • Scopus rating (2017): CiteScore 21.1 SJR 10.579 SNIP 3.627
Original language: English

Bibliographical note

© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Source: PubMed
Source ID: 28589679

Research output: Contribution to journalArticleScientificpeer-review

CFD based reactivity parameter determination for biomass particles of multiple size ranges in high heating rate devolatilization

This work presents a methodology that combines experimental measurements and Computational Fluid Dynamics (CFD) modeling to determine the global reaction kinetics of high heating rate biomass devolatilization. Three particle size ranges of woody biomass are analyzed: small (SF), medium (MF) and large (LF) fractions. Devolatilization mass loss is measured for each fraction in a laminar Drop-Tube Reactor (DTR) in nitrogen atmosphere, using two nominal reactor temperatures of 873 and 1173 K. Single First Order Reaction (SFOR) kinetics are determined by coupling an optimization routine with CFD models of the DTR. The global pre-exponential factors and activation energies for the SF, MF and LF particles are 5880 1/s and 42.7 kJ/mol, 48.1 1/s and 20.2 kJ/mol, and 102 1/s and 24.8 kJ/mol, respectively. These parameters are optimized for the isothermal heat transfer model available in CFD programs, and it is recommended that the specific heat capacity that was used in the optimization (1500 J/kgK) is used together with the parameters. Using the SF kinetics for small wood particles and either of the MF or LF kinetics for large particles, it is expected that more accurate devolatilization predictions can be obtained for the whole fuel size distribution in large scale CFD simulations.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Power Plant and Combustion Technology, Valmet Technologies Oy
Contributors: Niemelä, N. P., Tolvanen, H., Saarinen, T., Leppänen, A., Joronen, T.
Number of pages: 12
Pages: 676-687
Publication date: 1 Jun 2017
Peer-reviewed: Yes

Publication information

Journal: Energy
Volume: 128
ISSN (Print): 0360-5442
Ratings: 
  • Scopus rating (2017): CiteScore 5.6 SJR 1.99 SNIP 1.941
Original language: English
ASJC Scopus subject areas: Pollution, Energy(all)
Keywords: Biomass, Computational Fluid Dynamics (CFD), Devolatilization, High heating rate, Pyrolysis, Single First Order Reaction (SFOR)
Source: Scopus
Source ID: 85018474683

Research output: Contribution to journalArticleScientificpeer-review

Impact of film thickness of ultra-thin dip-coated compact TiO2 layers on the performance of mesoscopic perovskite solar cells

Uniform and pinhole-free electron selective TiO2 layers are of utmost importance for efficient perovskite solar cells. Here we used a scalable and low-cost dip coating method to prepare uniform and ultra-thin (5−50 nm) compact TiO2 films on fluorine doped tin oxide (FTO) glass substrates. The thickness of the film was tuned by changing the TiCl4 precursor concentration. The formed TiO2 follows the texture of the underlying FTO substrates, but at higher TiCl4 concentrations, the surface roughness is substantially decreased. This change occurs at a film thickness close to 20–30 nm. A similar TiCl4 concentration is needed to produce crystalline TiO2 films. Furthermore, below this film thickness, the underlying FTO might be exposed resulting in pinholes in the compact TiO2 layer. When integrated into mesoscopic perovskite solar cells, there appears to be a similar critical compact TiO2 layer thickness above which the devices perform more optimally. The power conversion efficiency was improved by more than 50% (from 5.5% to ~8.6%) when inserting a compact TiO2 layer. Devices without or with very thin compact TiO2 layers display J-V curves with an “s-shaped” feature in the negative voltage range, which could be attributed to immobilized negative ions at the electron-extracting interface. A strong correlation between the magnitude of the s-shape feature and the exposed FTO seen in the x-ray photoelectron spectroscopy measurements indicates that the s-shape is related to pinholes in the compact TiO2 layer when it is too thin.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Supramolecular photochemistry, Åbo Akademi, Aalto University
Contributors: Masood, M. T., Weinberger, C., Sarfraz, J., Rosqvist, E., Sandén, S., Sandberg, O., Vivo, P., Hashmi, G., Lund, P. D., Österbacka, R., Smått, J.
Pages: 17906-17913
Publication date: 31 May 2017
Peer-reviewed: Yes

Publication information

Journal: ACS Applied Materials and Interfaces
Volume: 9
Issue number: 21
ISSN (Print): 1944-8244
Ratings: 
  • Scopus rating (2017): CiteScore 8.15 SJR 2.784 SNIP 1.543
Original language: English

Research output: Contribution to journalArticleScientificpeer-review

Charge Carrier Dynamics in Solar Water Oxidation

The search for sustainable energy sources is one of the greatest problems facing mankind in the 21st century. Most renewable sources do not have adequate potential to cover the growing need for energy in order to sustain economic and population growth. Solar power is a plausible way to fully cover mankind’s continuously growing need for energy. However, sunlight is diurnal, and the amount of sunlight received at different latitudes of the Earth varies drastically. Harnessing solar energy into chemical bonds is an attractive approach to enable the storage of energy for transportation and later use. Direct photoelectrochemical water splitting produces only oxygen and hydrogen, of which hydrogen can be used to sustain a possible hydrogen based economy. The materials used in this Thesis are metal oxide semiconductors that act as photoanodes, performing the water oxidation reaction on their surface and supplying electrons for the water reduction reaction.

Hematite is an n-type metal oxide semiconductor that has a band gap suitable for the absorption of a noticeable fraction of solar radiation. The absorption of light leads to the generation of electron-hole pairs that are separated due to a built-in electric field. However, the conduction band level of hematite is not suitable for unassisted water splitting and it suffers from poor intrinsic charge transport properties. For this reason the photoanodes studied in this Thesis have been modified with doping and by forming heterojunctions with other metal oxide semiconductors, namely titanium dioxide.

This Thesis studies the evolution of the primary charge carriers responsible for water splitting in modified hematite photoanodes. The method selected to probe the charge carrier dynamics is transient absorption spectroscopy that enables the monitoring of charge carriers from the subpicosecond timescale up to seconds. The measurements were performed in a three electrode photoelectrochemical cell to see the effects of additional bias voltage on the charge carrier dynamics and how the recombination and oxygen evolution reaction are changed when a photocurrent is generated.

The results of this Thesis indicate that the modification of hematite has a profound effect on the charge carrier behaviour. The observed effects range from changes in recombination on the picosecond timescale, to nanosecond timescale trapping of electrons into intraband or surface states, and all the way to changes in the reaction rates of long-lived holes in the hundreds of milliseconds timescale.

General information

Publication status: Published
MoE publication type: G5 Doctoral dissertation (article)
Organisations: Chemistry and Bioengineering, Research group: Supramolecular photochemistry
Contributors: Ruoko, T.
Number of pages: 49
Publication date: 24 May 2017

Publication information

Publisher: Tampere University of Technology
ISBN (Print): 978-952-15-3951-0
ISBN (Electronic): 978-952-15-3955-8
Original language: English

Publication series

Name: Tampere University of Technology. Publication
Volume: 1473
ISSN (Print): 1459-2045

Research output: Book/ReportDoctoral thesisCollection of Articles

Biohydrogen production from xylose by fresh and digested activated sludge at 37, 55 and 70 °C

Two heat–treated inocula, fresh and digested activated sludge from the same municipal wastewater treatment plant, were compared for their H2 production via dark fermentation at mesophilic (37 °C), thermophilic (55 °C) and hyperthermophilic (70 °C) conditions using xylose as the substrate. At both 37 and 55 °C, the fresh activated sludge yielded more H2 than the digested sludge, whereas at 70 °C, neither of the inocula produced H2 effectively. A maximum yield of 1.85 mol H2 per mol of xylose consumed was obtained at 55 °C. H2 production was linked to acetate and butyrate production, and there was a linear correlation (R2 = 0.96) between the butyrate and H2 yield for the fresh activated sludge inoculum at 55 °C. Approximately 2.4 mol H2 per mol of butyrate produced were obtained against a theoretical maximum of 2.0, suggesting that H2 was produced via the acetate pathway prior to switching to the butyrate pathway due to the increased H2 partial pressure. Clostridia sp. were the prevalent species at both 37 and 55 °C, irrespectively of the inoculum type. Although the two inocula originated from the same plant, different thermophilic microorganisms were detected at 55 °C. Thermoanaerobacter sp., detected only in the fresh activated sludge cultures, may have contributed to the high H2 yield obtained with such an inoculum.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Industrial Bioengineering and Applied Organic Chemistry, Institute for Water Education, Hydraulic and Environmental Engineering (IHE) Inst. for Water Education
Contributors: Dessì, P., Lakaniemi, A., Lens, P. N. L.
Number of pages: 10
Pages: 120-129
Publication date: 15 May 2017
Peer-reviewed: Yes

Publication information

Journal: Water Research
Volume: 115
ISSN (Print): 0043-1354
Ratings: 
  • Scopus rating (2017): CiteScore 7.55 SJR 2.601 SNIP 2.388
Original language: English
ASJC Scopus subject areas: Ecological Modelling, Water Science and Technology, Waste Management and Disposal, Pollution
Keywords: Biohydrogen, Butyrate, Dark fermentation, Inocula, Temperature, Xylose
Electronic versions: 
URLs: 
Source: Scopus
Source ID: 85014366720

Research output: Contribution to journalArticleScientificpeer-review

The effects of calcium and potassium on CO2 gasification of birch wood in a fluidized bed

Birch wood was leached of its naturally occurring ash forming elements and doped with three concentrations of calcium or potassium before being gasified in a laboratory bubbling fluidized bed reactor. The wood samples were pelletized and inserted into a fluidized bed reactor where they were first pyrolyzed with N2 and then gasified with CO2. In addition to tracking the gas concentration of the exit gas, char samples were taken from the fluidized bed and analyzed to study the char properties. The presence of potassium in the biomass was found to have a significant influence on the structure of the resulting char, however potassium did not have an observable catalytic effect on the overall gasification reaction rate with CO2 due to the formation of a unreactive coke layer on the char surface. In contrast, calcium did increase the char conversion rate and is likely the primary active catalyst in gasification of birch wood with CO2.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Industrial Bioengineering and Applied Organic Chemistry, Chemistry and Bioengineering, Research group: Power Plant and Combustion Technology, Universidad de Sevilla, Johan Gadolin Process Chemistry Centre, Abo Akademi University, Univ of Oulu
Contributors: Kramb, J., Gómez-Barea, A., DeMartini, N., Romar, H., Doddapaneni, T. R. K. C., Konttinen, J.
Number of pages: 10
Pages: 398-407
Publication date: 15 May 2017
Peer-reviewed: Yes

Publication information

Journal: Fuel
Volume: 196
ISSN (Print): 0016-2361
Ratings: 
  • Scopus rating (2017): CiteScore 5.4 SJR 1.891 SNIP 2.127
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Fuel Technology, Energy Engineering and Power Technology, Organic Chemistry
Keywords: Biomass, Catalysts, Char, Fluidized bed, Gasification
Source: Scopus
Source ID: 85012050856

Research output: Contribution to journalArticleScientificpeer-review

Photoinduced Electron Injection from Zinc Phthalocyanines into Zinc Oxide Nanorods: Aggregation Effects

Phthalocyanines (Pc) are well-known light-harvesting compounds. However, despite the tremendous efforts on phthalocyanine synthesis, the achieved energy conversion efficiencies for Pc-based dye-sensitized solar cells are moderate. To cast light on the factors reducing the conversion efficiency, we have undertaken a time-resolved spectroscopy study of the primary photoinduced reactions at a semiconductor-Pc interface. ZnO nanorods were chosen as a model semiconductor substrate with enhanced specific surface area. The use of a nanostructured oxide surface allows to extend the semiconductor-dye interface with a hole transporting layer (spiro-MeOTAD) in a controlled way, making the studied system closer to a solid-state dye-sensitized solar cell. Four zinc phthalocyanines are compared in this study. The compounds are equipped with bulky peripheral groups designed to reduce the self-aggregation of the Pcs. Almost no signs of aggregation can be observed from the absorption spectra of the Pcs assembled on a ZnO surface. Nevertheless, the time-resolved spectroscopy indicates that there are inter-Pc charge separation-recombination processes in the time frame of 1-100 ps. This may reduce the electron injection efficiency into the ZnO by more than 50%, pointing out to a remaining aggregation effect. Surprisingly, the electron injection time does not correlate with the length of the linker connecting the Pc to ZnO. A correlation between the electron injection time and the "bulkiness" of the peripheral groups was observed. This correlation is further discussed with the use of computational modeling of the Pc arrangements on the ZnO surface. (Figure Presented).

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Instituto Madrileño de Estudios Avanzados (IMDEA)-Nanociencia, Universidad Autónoma de Madrid, Mersin University, South-Ukrainian National Pedagogical University
Contributors: Virkki, K., Hakola, H., Urbani, M., Tejerina, L., Ince, M., Martínez-Díaz, M. V., Torres, T., Golovanova, V., Golovanov, V., Tkachenko, N. V.
Number of pages: 12
Pages: 9594-9605
Publication date: 4 May 2017
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry C
Volume: 121
Issue number: 17
ISSN (Print): 1932-7447
Ratings: 
  • Scopus rating (2017): CiteScore 4.58 SJR 2.135 SNIP 1.135
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Energy(all), Surfaces, Coatings and Films, Physical and Theoretical Chemistry
Source: Scopus
Source ID: 85020915273

Research output: Contribution to journalArticleScientificpeer-review

Alkyl thiophene vinylene electropolymerization in C8mimPF6, potential use in solar cells

We report the electrosynthesis of a novel semiconductor polymer based on alkyl vinylthiophene derivative in the presence of an ionic liquid (IL). The polymerization was performed under galvanostatic conditions and the polymer was studied as potential donor component of a multilayer heterojunction organic solar cell (OSC). The monomer used was (E)-1,2-di-(3-octyl-2-thienyl) vinylene (OTV) and the IL used for the electropolymerization was 1-octyl-3-methylimidazole hexafluorophosphate C8mimPF6. Optical properties, stability and morphology of the polymer were analyzed using FT-IR, UV-vis, Raman and XPS spectroscopy. Voltammetry analysis and scanning electron microscopy (SEM-EDX) were also performed on the polymer. The OSC assembled with the polymer of OTV was used as electro donor and C60 as acceptor. Molybdenum trioxide (MoO3) and bathocuproine (BCP) were used as buffer layer between anode and cathode respectively. I-V curves, in the dark and under AM 1.5 solar simulator were performed to measure its efficiency.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Supramolecular photochemistry, Research group: Chemistry & Advanced Materials
Contributors: Rojas, V., Martinez, F., Bernede, J. C., Guenadez, L. C., Efimov, A., Lemmetyinen, H.
Number of pages: 13
Pages: 405-417
Publication date: May 2017
Peer-reviewed: Yes

Publication information

Journal: Materials Sciences and Applications
Volume: 8
Issue number: 5
ISSN (Print): 2153-117X
Original language: English

Research output: Contribution to journalArticleScientificpeer-review

Elucidation of Compression-Induced Surface Crystallization in Amorphous Tablets Using Sum Frequency Generation (SFG) Microscopy

Purpose: To investigate the effect of compression on the crystallization behavior in amorphous tablets using sum frequency generation (SFG) microscopy imaging and more established analytical methods. Method: Tablets containing neat amorphous griseofulvin with/without excipients (silica, hydroxypropyl methylcellulose acetate succinate (HPMCAS), microcrystalline cellulose (MCC) and polyethylene glycol (PEG)) were prepared. They were analyzed upon preparation and storage using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy (SEM) and SFG microscopy. Results: Compression-induced crystallization occurred predominantly on the surface of the neat amorphous griseofulvin tablets, with minimal crystallinity being detected in the core of the tablets. The presence of various types of excipients was not able to mitigate the compression-induced surface crystallization of the amorphous griseofulvin tablets. However, the excipients affected the crystallization rate of amorphous griseofulvin in the core of the tablet upon compression and storage. Conclusions: SFG microscopy can be used in combination with ATR-FTIR spectroscopy and SEM to understand the crystallization behaviour of amorphous tablets upon compression and storage. When selecting excipients for amorphous formulations, it is important to consider the effect of the excipients on the physical stability of the amorphous formulations.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, University of Helsinki, Division of Biopharmaceutical Sciences, Biomedicum Imaging Unit, FIN-00014 University of Helsinki
Contributors: Mah, P. T., Novakovic, D., Saarinen, J., van Landeghem, S., Peltonen, L., Laaksonen, T., Isomäki, A., Strachan, C. J.
Number of pages: 14
Pages: 957-970
Publication date: May 2017
Peer-reviewed: Yes
Early online date: 13 Oct 2016

Publication information

Journal: Pharmaceutical Research
Volume: 34
Issue number: 5
ISSN (Print): 0724-8741
Ratings: 
  • Scopus rating (2017): CiteScore 3.3 SJR 1.077 SNIP 1.054
Original language: English
ASJC Scopus subject areas: Biotechnology, Molecular Medicine, Pharmacology, Pharmaceutical Science, Organic Chemistry, Pharmacology (medical)
Source: Scopus
Source ID: 84991051806

Research output: Contribution to journalArticleScientificpeer-review

Crystallisation-enhanced bulk hole mobility in phenothiazine-based organic semiconductors

A series of three novel donor-acceptor systems based on C(3)-malononitrile-substituted phenothiazines was synthesised in good overall yields and their thermal, spectroscopic, and electrochemical properties were characterised. The compounds were prepared through a sequence of Ullmann-coupling, Vilsmeier-Haack formylation and Knoevenagel-condensation, followed by Suzuki-coupling reactions for introduction of aryl substitutents at C(7) position of the phenothiazine. The introduction of a donor unit at the C(7) position exhibited a weak impact on the optical and electrochemical characteristics of the compounds and led to amorphous films with bulk hole mobilities in the typical range reported for phenothiazines, despite the higher charge delocalisation as attested by computational studies. In contrast, highly ordered films were formed when using the C(7)-unsubstituted 3-malononitrile phenothiazine, exhibiting an outstanding mobility of 1 × 10−3 cm2 V−1 s−1, the highest reported for this class of compounds. Computational conformational analysis of the new phenothizanes suggested that free rotation of the substitutents at the C(7) position suppresses the ordering of the system, thereby hampering suitable packing of the new materials needed for high charge carrier mobility.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Research group: Industrial Bioengineering and Applied Organic Chemistry, Research group: Supramolecular photochemistry
Contributors: Shinde, D. B., Salunke, J. K., Candeias, N. R., Francesca, T., Massimo, G., Wadgaonkar, P. P., Priimagi, A., Nadia, C., Vivo, P.
Number of pages: 10
Publication date: 12 Apr 2017
Peer-reviewed: Yes

Publication information

Journal: Scientific Reports
Volume: 7
Article number: 46268
ISSN (Print): 2045-2322
Ratings: 
  • Scopus rating (2017): CiteScore 4.36 SJR 1.533 SNIP 1.258
Original language: English

Research output: Contribution to journalArticleScientificpeer-review

Building up colors: multilayered arrays of peryleneimides on flat surfaces and on mesoporous layers

Novel monoisomeric perylene imide derivatives with terpyridinyl and pyrrolidinyl substituents were synthesized and deposited onto solid substrates, such as a thin film of Al2O3 and mesoporous TiO2 nanoparticle layer, by using a simple dip-by-dip method. Arrays of up to 33 layers were built on Al2O3. In the case of mesoporous TiO2, the interstitial volume between the particles was filled up with dye assemblies. Deposition could produce either layers of microcrystals or molecular layers if an appropriate washing procedure was used. The resultant arrays were studied by means of scanning electron microscopy, X-ray photoelectron spectroscopy measurements, and UV/Vis absorption.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Supramolecular photochemistry, Research group: Industrial Bioengineering and Applied Organic Chemistry, Photonics, Research group: Surface Science
Contributors: George, L., Efimova, E., Sariola-Leikas, E., Lahtonen, K., Valden, M., Vivo, P., Hakola, H., Hiltunen, A., Efimov, A.
Publication date: 7 Apr 2017
Peer-reviewed: Yes

Publication information

Journal: ChemPlusChem
ISSN (Print): 2192-6506
Ratings: 
  • Scopus rating (2017): CiteScore 2.79 SJR 1.051 SNIP 0.607
Original language: English

Research output: Contribution to journalArticleScientificpeer-review

Halogen bonding stabilizes a cis-azobenzene derivative in the solid state: A crystallographic study

Crystals of trans- and cis-isomers of a fluorinated azobenzene derivative have been prepared and characterized by single-crystal X-ray diffraction. The presence of F atoms on the aromatic core of the azobenzene increases the lifetime of the metastable cis-isomer, allowing single crystals of the cis-azobenzene to be grown. Structural analysis on the cis-azobenzene, complemented with density functional theory calculations, highlights the active role of the halogen-bond contact (N...I synthon) in promoting the stabilization of the cis-isomer. The presence of a long aliphatic chain on the azobenzene unit induces a phase segregation that stabilizes the molecular arrangement for both the trans- and cis-isomers. Due to the rarity of cis-azobenzene crystal structures in the literature, our paper makes a step towards understanding the role of non-covalent interactions in driving the packing of metastable azobenzene isomers. This is expected to be important in the future rational design of solid-state, photoresponsive materials based on halogen bonding. We show by single-crystal X-ray diffraction studies and computational analysis that halogen bonding can stabilize a metastable cis-azobenzene derivative in the solid state.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Supramolecular photochemistry, Research group: Chemistry & Advanced Materials, Politecnico di Milano, Aalto University
Contributors: Saccone, M., Siiskonen, A., Fernandez-Palacio, F., Priimägi, A., Terraneo, G., Resnati, G., Metrangolo, P.
Number of pages: 7
Pages: 227-233
Publication date: 1 Apr 2017
Peer-reviewed: Yes

Publication information

Journal: ACTA CRYSTALLOGRAPHICA SECTION B : STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS
Volume: 73
Issue number: 2
ISSN (Print): 2052-5192
Ratings: 
  • Scopus rating (2017): CiteScore 4.54
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Atomic and Molecular Physics, and Optics, Metals and Alloys, Materials Chemistry
Keywords: azobenzene, halogen bonding, isomerization
Source: Scopus
Source ID: 85017113549

Research output: Contribution to journalArticleScientificpeer-review

High-rate autotrophic denitrification in a fluidized-bed reactor at psychrophilic temperatures

In this study, high-rate autotrophic denitrification driven by thiosulfate (S2O32-) was maintained under psychrophilic conditions in a lab-scale fluidized-bed reactor (FBR) with a Thiobacillus-dominated biofilm. The temperature effects on the denitrifying performance of the FBR were monitored by gradually decreasing the temperature from 20 to 3°C. The potential of the FBR biofilm to maintain thiosulfate-driven denitrification at 3°C was further investigated at different HRTs (5.4, 3 and 1 h) and influent NO3- concentrations (200, 600 and 1078 mg/L), resulting in a gradual increase of the nitrogen loading rate (NLR) from 0.20 to 3.3 kg N-NO3-/m3 d. Complete thiosulfate-driven denitrification could be maintained at all temperatures, HRTs and influent NO3- concentrations tested. PCR-DGGE analysis revealed the dominance of the sulfur-oxidizing chemolithotrophs T. denitrificans and T. thioparus at all temperatures investigated. The FBR operation at a temperature as low as 3°C promoted bed expansion and increased the dissolved organic carbon (DOC) concentration in the effluent, but had no significant effects on the denitrification efficiency. The findings of this study are highly significant for the treatment of cold nitrogen-contaminated waters poor in organics and confirm the FBR as a robust and powerful bioreactor system for autotrophic denitrification.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Research group: Industrial Bioengineering and Applied Organic Chemistry
Contributors: Di Capua, F., Milone, I., Lakaniemi, A., N.L. Lens, P., Esposito, G.
Publication date: Apr 2017
Peer-reviewed: Yes
Early online date: 25 Dec 2016

Publication information

Journal: Chemical Engineering Journal
ISSN (Print): 1385-8947
Ratings: 
  • Scopus rating (2017): CiteScore 7.01 SJR 1.863 SNIP 1.96
Original language: English
Keywords: Autotrophic denitrification, Fluidized-bed reactor, Psychrophilic temperatures, Thiobacillus, Thiosulfate
Source: RIS
Source ID: urn:AA12A584D952BB2C4FADD94785C8DAC9

Research output: Contribution to journalArticleScientificpeer-review

Hydrophobin-nanofibrillated cellulose stabilized emulsions for encapsulation and release of BCS class II drugs

The purpose of this study was to construct biopolymer-based oil-in-water emulsion formulations for encapsulation and release of poorly water soluble model compounds naproxen and ibuprofen. Class II hydrophobin protein HFBII from Trichoderma reesei was used as a surfactant to stabilize the oil/water interfaces of the emulsion droplets in the continuous aqueous phase. Nanofibrillated cellulose (NFC) was used as a viscosity modifier to further stabilize the emulsions and encapsulate protein coated oil droplets in NFC fiber network. The potential of both native and oxidized NFC were studied for this purpose. Various emulsion formulations were prepared and the abilities of different formulations to control the drug release rate of naproxen and ibuprofen, used as model compounds, were evaluated. The optimal formulation for sustained drug release consisted of 0.01% of drug, 0.1% HFBII, 0.15% oxidized NFC, 10% soybean oil and 90% water phase. By comparison, the use of native NFC in combination with HFBII resulted in an immediate drug release for both of the compounds. The results indicate that these NFC originated biopolymers are suitable for pharmaceutical emulsion formulations. The native and oxidized NFC grades can be used as emulsion stabilizers in sustained and immediate drug release applications. Furthermore, stabilization of the emulsions was achieved with low concentrations of both HFBII and NFC, which may be an advantage when compared to surfactant concentrations of conventional excipients traditionally used in pharmaceutical emulsion formulations.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering