Formation of corrosion products on zinc in wet supercritical and subcritical CO2: In-situ spectroscopic study

Formation of corrosion products on zinc was investigated with in-situ Raman and FTIR when exposed to wet supercritical carbon dioxide (scCO2) and subsequent depressurization. Zinc oxide (ZnO) and smithsonite (ZnCO3) formed on zinc in scCO2. The dissolved water precipitated as liquid water in the reaction cell during depressurization. Formation of ZnO, ZnCO3 and a needle-like zinc hydroxy carbonate species on zinc was observed inside a sessile water droplet during conditions simulating the depressurization phase. Addition of oxygen accelerated the formation of the carbonate species due to higher cathodic activity that increased zinc dissolution.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Ceramic materials, CNRS, Université de Bordeaux, ICMCB, Top Analytica Oy, SSAB
Contributors: Kaleva, A., Tassaing, T., Saarimaa, V., Le Bourdon, G., Väisänen, P., Markkula, A., Levänen, E.
Number of pages: 10
Publication date: 1 Sep 2020
Peer-reviewed: Yes

Publication information

Journal: Corrosion Science
Volume: 174
ISSN (Print): 0010-938X
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all), Materials Science(all)
Keywords: Acid corrosion, IR spectroscopy, Oxidation, Raman spectroscopy, SEM, Zinc
Electronic versions: 
Source: Scopus
Source ID: 85087488046

Research output: Contribution to journalArticleScientificpeer-review

Optimization of photogenerated charge carrier lifetimes in ald grown tio2 for photonic applications

Titanium dioxide (TiO2) thin films are widely employed for photocatalytic and photovoltaic applications where the long lifetime of charge carriers is a paramount requirement for the device efficiency. To ensure the long lifetime, a high temperature treatment is used which restricts the applicability of TiO2 in devices incorporating organic or polymer components. In this study, we exploited low temperature (100–150 C) atomic layer deposition (ALD) of 30 nm TiO2 thin films from tetrakis(dimethylamido)titanium. The deposition was followed by a heat treatment in air to find the minimum temperature requirements for the film fabrication without compromising the carrier lifetime. Femto-to nanosecond transient absorption spectroscopy was used to determine the lifetimes, and grazing incidence X-ray diffraction was employed for structural analysis. The optimal result was obtained for the TiO2 thin films grown at 150 C and heat-treated at as low as 300 C. The deposited thin films were amorphous and crystallized into anatase phase upon heat treatment at 300–500 C. The average carrier lifetime for amorphous TiO2 is few picoseconds but increases to >400 ps upon crystallization at 500 C. The samples deposited at 100 C were also crystallized as anatase but the carrier lifetime was <100 ps.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Physics, Research group: Surface Science, Research group: ORC, Research group: Chemistry & Advanced Materials
Contributors: Khan, R., Ali-Löytty, H., Saari, J., Valden, M., Tukiainen, A., Lahtonen, K., Tkachenko, N. V.
Number of pages: 9
Publication date: 10 Aug 2020
Peer-reviewed: Yes

Publication information

Journal: Nanomaterials
Volume: 10
Issue number: 8
Article number: 1567
ISSN (Print): 2079-4991
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Materials Science(all)
Keywords: Atomic layer deposition, Lifetime of charge carriers, Thin films, Titanium dioxide, Transient absorption spectroscopy
Source: Scopus
Source ID: 85089562888

Research output: Contribution to journalArticleScientificpeer-review

Nucleation and growth behavior of Er3+doped oxyfluorophosphate glasses

The nucleation and growth behavior of glasses with the composition (75 NaPO3-25 CaF2)100-x-(TiO2/ZnO/MgO)x, with x = 0 and x = 1.5 (in mol%) is investigated. The glasses possess similar activation energy for crystallization and Johnson-Mehl-Avrami exponent, with value 2 confirming bulk crystallization of crystals with needle like shape. The Ti and Mg glasses exhibit broader nucleation curve and higher Tn max than the x = 0 and Zn glasses due to their stronger field strength. The crystal growth rates were determined and validated using SEM. Finally, we showed that the nucleation and growth of glasses can be controlled due to the large difference between onset of crystallization and maximum nucleation temperature which is crucial when preparing novel transparent glass-ceramics.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Research group: Photonics Glasses, BioMediTech, Research group: Biomaterials and Tissue Engineering Group, Fondazione LINKS – Leading Innovation & Knowledge for Society
Contributors: Ojha, N., Szczodra, A., Boetti, N. G., Massera, J., Petit, L.
Number of pages: 14
Pages: 25703-25716
Publication date: 7 Jul 2020
Peer-reviewed: Yes

Publication information

Journal: RSC Advances
Volume: 10
Issue number: 43
ISSN (Print): 2046-2069
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all)
Source: Scopus
Source ID: 85091239098

Research output: Contribution to journalArticleScientificpeer-review

Additive manufacturing of monolithic supercapacitors with biopolymer separator

In this paper, additive layer-by-layer fabrication of a fully screen printed monolithic supercapacitor exhibiting performance comparable with supercapacitors prepared using lamination is reported. A novel separator material improves the performance of the monolithic supercapacitor, is easily applicable using scalable processes such as screen and stencil printing, and is based on sustainable biomaterials. The additive monolithic manufacturing offers advantages for system integration and avoids the need of an additional alignment step as needed in the fabrication of laminated supercapacitors. Previously, the monolithically fabricated supercapacitors showed higher equivalent series resistance (ESR) and leakage current than the laminated ones. By using microfibrillated cellulose (MFC) and chitosan as separator materials ESR and leakage current were decreased. These disposable and non-toxic aqueous electrolyte supercapacitors are optimized for autonomous sensor systems, for example in Internet-of-Things (IoT) applications, with capacitance of 200–300 mF and ESR of about 10 Ω. The new composite separator material consisting of MFC and chitosan has good adhesion on the electrodes and the substrate, is easy to apply using printing and coating processes, and does not diffuse into the porous electrode. Graphic Abstract: [Figure not available: see fulltext.].

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Engineering, Automation Technology and Mechanical Engineering, BioMediTech, Abo Akademi University
Contributors: Arvani, M., Keskinen, J., Railanmaa, A., Siljander, S., Björkqvist, T., Tuukkanen, S., Lupo, D.
Number of pages: 9
Pages: 689-697
Publication date: 1 Jun 2020
Peer-reviewed: Yes

Publication information

Journal: Journal of Applied Electrochemistry
Volume: 50
Issue number: 6
ISSN (Print): 0021-891X
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Electrochemistry, Materials Chemistry
Keywords: Chitosan, Energy storage, MFC, Microfibrillated cellulose, Nanocellulose, Printed electronics, Separator, Supercapacitors
Source: Scopus
Source ID: 85085106449

Research output: Contribution to journalArticleScientificpeer-review

Utilizing Gelatinized Starchy Waste from Rice Noodle Factory as Substrate for L(+)-Lactic Acid Production by Amylolytic Lactic Acid Bacterium Enterococcus faecium K-1

To valorize starchy waste from rice noodle factory, bioconversion of gelatinized starchy waste (GSW) to value-added product as L(+)-lactic acid, the monomer for polylactate synthesis, was investigated using amylolytic lactic acid bacterium, Enterococcus faecium K-1. Screening for appropriate nitrogen source to replace expensive organic nitrogen sources revealed that corn steep liquor (CSL) was the most suitable regarding high efficacy for L(+)-LA achievement and low-cost property. The successful applying statistic experimental design, Plackett-Burman design incorporated with central composite design (CCD), predicted the maximum L(+)-LA of 93.07 g/L from the optimized medium (OM) containing 125.7 g/L GSW and 207.3 g/L CSL supplemented with CH3COONa, MgSO4, MnSO4, K2HPO4, CaCl2, (NH4)2HC6H5O7, and Tween80. Minimizing the medium cost by removal of all inorganic salts and Tween80 from OM was not an effect on L(+)-LA yield. Fermentation using the optimized medium without minerals (OM-Mi) containing only GSW (125.7 g/L) and CSL (207.3 g/L) in a 10-L fermenter was also successful. Thinning GSW with α-amylase from Lactobacillus plantarum S21 increased L(+)-LA productivity in the early stage of 24-h fermentation. Not only showing the feasible bioconversion process for GSW utilizing as a substrate for L(+)-LA production, this research also demonstrated the efficient model for industrial starchy waste valorization.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Chiang Mai University, North Dakota State University
Contributors: Unban, K., Khanongnuch, R., Kanpiengjai, A., Shetty, K., Khanongnuch, C.
Publication date: May 2020
Peer-reviewed: Yes

Publication information

Journal: Applied Biochemistry and Biotechnology
ISSN (Print): 0273-2289
Original language: English
ASJC Scopus subject areas: Biotechnology, Bioengineering, Biochemistry, Applied Microbiology and Biotechnology, Molecular Biology
Keywords: ALAB, Enterococcus faecium, L-lactic acid, Low-cost medium, Starchy waste
Source: Scopus
Source ID: 85084316077

Research output: Contribution to journalArticleScientificpeer-review

Evaluation of scaffold microstructure and comparison of cell seeding methods using micro-computed tomography-based tools

Micro-computed tomography (micro-CT) provides a means to analyse and model three-dimensional (3D) tissue engineering scaffolds. This study proposes a set of micro-CT-based tools firstly for evaluating the microstructure of scaffolds and secondly for comparing different cell seeding methods. The pore size, porosity and pore interconnectivity of supercritical CO2 processed poly(l-lactide-co-ɛ-caprolactone) (PLCL) and PLCL/β-tricalcium phosphate scaffolds were analysed using computational micro-CT models. The models were supplemented with an experimental method, where iron-labelled microspheres were seeded into the scaffolds and micro-CT imaged to assess their infiltration into the scaffolds. After examining the scaffold architecture, human adipose-derived stem cells (hASCs) were seeded into the scaffolds using five different cell seeding methods. Cell viability, number and 3D distribution were evaluated. The distribution of the cells was analysed using micro-CT by labelling the hASCs with ultrasmall paramagnetic iron oxide nanoparticles. Among the tested seeding methods, a forced fluid flow-based technique resulted in an enhanced cell infiltration throughout the scaffolds compared with static seeding. The current study provides an excellent set of tools for the development of scaffolds and for the design of 3D cell culture experiments.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: BioMediTech, Research group: Biomaterials and Tissue Engineering Group, Research group: Computational Biophysics and Imaging Group, Orton Orthopaedic Hospital, Tampere University Hospital
Contributors: Palmroth, A., Pitkänen, S., Hannula, M., Paakinaho, K., Hyttinen, J., Miettinen, S., Kellomäki, M.
Number of pages: 12
Publication date: 1 Apr 2020
Peer-reviewed: Yes

Publication information

Journal: Journal of the Royal Society. Interface
Volume: 17
Issue number: 165
Article number: 20200102
ISSN (Print): 1742-5689
Original language: English
ASJC Scopus subject areas: Biotechnology, Biophysics, Bioengineering, Biomaterials, Biochemistry, Biomedical Engineering
Keywords: cell seeding, micro-CT, microsphere, supercritical CO2 processing, tissue engineering, USPIO

Bibliographical note

INT=bmte,"Miettinen, Susanna"

Research output: Contribution to journalArticleScientificpeer-review

Utilizing Neurons for Digital Logic Circuits: A Molecular Communications Analysis

With the advancement of synthetic biology, several new tools have been conceptualized over the years as alternative treatments for current medical procedures. As part of this work, we investigate how synthetically engineered neurons can operate as digital logic gates that can be used towards bio-computing inside the brain and its impact on epileptic seizure-like behaviour. We quantify the accuracy of logic gates under high firing rates amid a network of neurons and by how much it can smooth out uncontrolled neuronal firings. To test the efficacy of our method, simulations composed of computational models of neurons connected in a structure that represents a logic gate are performed. Our simulations demonstrate the accuracy of performing the correct logic operation, and how specific properties such as the firing rate can play an important role in the accuracy. As part of the analysis, the mean squared error is used to quantify the quality of our proposed model and predict the accurate operation of a gate based on different sampling frequencies. As an application, the logic gates were used to smooth out epileptic seizure-like activity in a biological neuronal network, where the results demonstrated the effectiveness of reducing its mean firing rate. Our proposed system has the potential to be used in future approaches to treating neurological conditions in the brain.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Engineering, Waterford Institute of Technology, Tampere University, Telecommunications Software and Systems Group (TSSG)
Contributors: Adonias, G. L., Yastrebova, A., Barros, M. T., Koucheryavy, Y., Cleary, F., Balasubramaniam, S.
Number of pages: 13
Pages: 224-236
Publication date: 1 Apr 2020
Peer-reviewed: Yes

Publication information

Journal: IEEE Transactions on Nanobioscience
Volume: 19
Issue number: 2
ISSN (Print): 1536-1241
Original language: English
ASJC Scopus subject areas: Biotechnology, Bioengineering, Medicine (miscellaneous), Biomedical Engineering, Pharmaceutical Science, Computer Science Applications, Electrical and Electronic Engineering
Keywords: Boolean algebra, Logic gates, nano communications, nanonetworks, synthetic biology

Bibliographical note

EXT="Balasubramaniam, Sasitharan"

Source: Scopus
Source ID: 85083430394

Research output: Contribution to journalArticleScientificpeer-review

Transparent Yb3+ doped phosphate glass-ceramics

Yb3+ doped oxyfluorophosphate glasses with the composition (98.75) [90NaPO3-(10-x) Na2O-xNaF] - 1.25Yb2O3 (in mol%) with x = 0, 2.5, 5, 7.5 and 10 were prepared using a standard melting process. The progressive replacement of Na2O by NaF leads to an increase in the number of Q2 units at the expense of the Q1 units. This increase in the polymerization of the glass network leads to a shift of the optical band gap to lower wavelength, to a slight increase in the intensity of the emission at 1000 nm and more importantly to a change in the glass crystallization process. Indeed, both surface and bulk crystallization were observed in the glass with x = 0 while surface crystallization only occurs when NaF is added in the phosphate network. The heat treatment leads to the precipitation of at least three crystalline phases: as x increases, the NaPO3 phase grows at the expense of Na5P3O10. All glasses precipitate the Yb containing crystal, NaYbP2O7 which leads to an increase in the intensity of the emission at 1000 nm compared to the emission at 975 nm. We show for the first time to the best of our knowledge that transparent Yb3+ doped phosphate glass-ceramics can be obtained within this glass system when free of NaF.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Fondazione LINKS – Leading Innovation & Knowledge for Society, CNRS, Université de Bordeaux, ICMCB
Contributors: Hongisto, M., Veber, A., Boetti, N. G., Danto, S., Jubera, V., Petit, L.
Publication date: 1 Jan 2020
Peer-reviewed: Yes

Publication information

Journal: Ceramics International
ISSN (Print): 0272-8842
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Ceramics and Composites, Process Chemistry and Technology, Surfaces, Coatings and Films, Materials Chemistry
Keywords: Glass-ceramic, Luminescence, Phosphate glass, XRD, Yb
Source: Scopus
Source ID: 85077933290

Research output: Contribution to journalArticleScientificpeer-review

Investigation of well-defined pinholes in TiO2 electron selective layers used in planar heterojunction perovskite solar cells

The recently introduced perovskite solar cell (PSC) technology is a promising candidate for providing low-cost energy for future demands. However, one major concern with the technology can be traced back to morphological defects in the electron selective layer (ESL), which deteriorates the solar cell performance. Pinholes in the ESL may lead to an increased surface recombination rate for holes, if the perovskite absorber layer is in contact with the fluorine-doped tin oxide (FTO) substrate via the pinholes. In this work, we used sol-gel-derived mesoporous TiO2 thin films prepared by block co-polymer templating in combination with dip coating as a model system for investigating the effect of ESL pinholes on the photovoltaic performance of planar heterojunction PSCs. We studied TiO2 films with different porosities and film thicknesses, and observed that the induced pinholes only had a minor impact on the device performance. This suggests that having narrow pinholes with a diameter of about 10 nm in the ESL is in fact not detrimental for the device performance and can even, to some extent improve their performance. A probable reason for this is that the narrow pores in the ordered structure do not allow the perovskite crystals to form interconnected pathways to the underlying FTO substrate. However, for ultrathin (~20 nm) porous layers, an incomplete ESL surface coverage of the FTO layer will further deteriorate the device performance.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Chemistry & Advanced Materials, Abo Akademi University, National University of Science & Technology (NUST), Paderborn University
Contributors: Masood, M. T., Qudsia, S., Hadadian, M., Weinberger, C., Nyman, M., Ahläng, C., Dahlström, S., Liu, M., Vivo, P., Österbacka, R., Smått, J. H.
Number of pages: 16
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: Nanomaterials
Volume: 10
Issue number: 1
Article number: 181
ISSN (Print): 2079-4991
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Materials Science(all)
Keywords: Dip coating, Electron selective layer, Evaporation-induced self-assembly, Mesoporous TiO, Perovskite solar cell, Pinhole
Source: Scopus
Source ID: 85078423754

Research output: Contribution to journalArticleScientificpeer-review

The thermal contact resistance of a steel-ceramic interface with oxide intermediates

Metal structures covered by refractories are widely employed in high temperature processes such as incineration and metal production. The thermal resistance in refractories used in high temperature processes is associated with different phases, phase boundaries and porosity in the refractory and with the thermal contact resistance between the refractory and the metal interface. Here, a light flash method was used to evaluate the thermal contact resistance of the ceramic/steel interface at temperatures of 25, 100, 200, 300 and 400 °C. The material combinations studied were a commonly-used reference ceramic, Pyroceram 9606, and pressure vessel steel with oxidizing treatment at 450 and 650 °C for 50 h. Thermal resistance at a ceramic/steel interface increased significantly when a porous oxide layer was formed on the steel surface. The thermal contact resistance of the interface varied from 0.1 to 0.4 × 10−3 m2K/W, depending on the temperature and the oxidization of the steel sample.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Environmental Systems R & D, Valmet Technologies Oy
Contributors: Silvonen, J., Levänen, E., Uusitalo, M.
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: Cogent Engineering
Volume: 7
Issue number: 1
Article number: 1720057
ISSN (Print): 2331-1916
Original language: English
ASJC Scopus subject areas: Computer Science(all), Chemical Engineering(all), Engineering(all)
Keywords: heat conduction, light flash, oxidation, refractory, thermal contact resistance
Source: Scopus
Source ID: 85079383199

Research output: Contribution to journalArticleScientificpeer-review

In-flightwind field identification and prediction of parafoil systems

The wind field is an essential factor that affects accurate homing and flare landing of parafoil systems. In order to obtain the ambient wind field during the descent of a parafoil system, a combination method of in-flight wind field identification and prediction is proposed. First, a wind identification method only using global position system information is derived based on the flight dynamics of parafoil systems. Then a wind field prediction model is constructed using the atmospheric dynamics, and the low-altitude wind field is predicted based on the identified wind field of high-altitude. Finally, simulations of wind field identification and prediction are conducted. The results demonstrate that the proposed method can identify the wind fields precisely and also predict the wind fields reasonably. This method can potentially be applied in practical parafoil systems to provide wind field information for homing tasks.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Computing Sciences, Research group: Predictive Society and Data Analytics (PSDA), Research group: Computational Medicine and Statistical Learning Laboratory (CMSL), Anhui Science and Technology University, Aalto University, Peking University, University of Applied Sciences Upper Austria, School of Management, Nankai University
Contributors: Gao, H., Tao, J., Dehmer, M., Emmert-Streib, F., Sun, Q., Chen, Z., Xie, G., Zhou, Q.
Number of pages: 15
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: Applied Sciences (Switzerland)
Volume: 10
Issue number: 6
Article number: 1958
ISSN (Print): 2076-3417
Original language: English
ASJC Scopus subject areas: Materials Science(all), Instrumentation, Engineering(all), Process Chemistry and Technology, Computer Science Applications, Fluid Flow and Transfer Processes
Keywords: Autonomous homing, Identification, Parafoil system, Prediction, Wind field
Source: Scopus
Source ID: 85082646563

Research output: Contribution to journalArticleScientificpeer-review

Efficient Conversion of Light to Chemical Energy: Directional, Chiral Photoswitches with Very High Quantum Yields

Photochromic systems have been used to achieve a number of engineering functions such as light energy conversion, molecular motors, pumps, actuators, and sensors. Key to practical applications is a high efficiency in the conversion of light to chemical energy, a rigid structure for the transmission of force to the environment, and directed motion during isomerization. We present a novel type of photochromic system (diindane diazocines) that converts visible light with an efficiency of 18 % to chemical energy. Quantum yields are exceptionally high with >70 % for the cis–trans isomerization and 90 % for the back-reaction and thus higher than the biochemical system rhodopsin (64 %). Two diastereomers (meso and racemate) were obtained in only two steps in high yields. Both isomers are directional switches with high conversion rates (76–99 %). No fatigue was observed after several thousands of switching cycles in both systems.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Graz University of Technology, University of Jyväskylä, Christian-Albrechts-Universität zu Kiel
Contributors: Moormann, W., Tellkamp, T., Stadler, E., Röhricht, F., Näther, C., Puttreddy, R., Rissanen, K., Gescheidt, G., Herges, R.
Number of pages: 6
Pages: 15081-15086
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: Angewandte Chemie - International Edition
Volume: 59
Issue number: 35
ISSN (Print): 1433-7851
Original language: English
ASJC Scopus subject areas: Catalysis, Chemistry(all)
Keywords: diazocine, energy conversion, photochemistry, photochromism, quantum yields
Source: Scopus
Source ID: 85086003194

Research output: Contribution to journalArticleScientificpeer-review

Modelling of a pressure swing adsorption unit by deep learning and artificial Intelligence tools

Syngas is one of the main sources available for the production of pure H2 and synthetic fuels, among others. Pressure swing adsorption (PSA) is considered to be an efficient alternative for pre-treatment of syngas. However, it displays very complex dynamical behaviour. This work proposes the development of different Artificial Intelligence based models for the prediction of the dynamic behaviour of several process output variables. A classical model of ANNs, a machine learning model and a deep learning model was here developed. It was found that Deep Learning networks were the only ones capable of fully representing the dynamic behaviour of the PSA unit, whereas the other models were only partially capable of predicting it. Thus, it is proposed a reliable real-time soft sensor for a PSA unit based on Deep Leaning strategy. This strategy provides bases to overtake several problems associated to this processes control, operation and optimization.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Automation Technology and Mechanical Engineering, Universidade do Porto
Contributors: Oliveira, L. M. C., Koivisto, H., Iwakiri, I. G., Loureiro, J. M., Ribeiro, A. M., Nogueira, I. B.
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: Chemical Engineering Science
Volume: 224
Article number: 115801
ISSN (Print): 0009-2509
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all), Industrial and Manufacturing Engineering
Keywords: Artificial intelligence, Artificial neural networks, Deep learning, Machine learning, Pressure swing adsorption, Syngas

Bibliographical note

EXT="Nogueira, Idelfonso B.R."

Source: Scopus
Source ID: 85085301174

Research output: Contribution to journalArticleScientificpeer-review

CFD modeling the diffusional losses of nanocluster-sized particles and condensing vapors in 90° bends of circular tubes

Particle and vapor measurements typically include sampling tubing causing sampling losses therein. Correcting measured concentrations from the sampling losses using the calculated penetration efficiencies of straight tubes is a satisfactory approximation if sub-micrometer particles are of interest. However, in addition to inertial impaction of larger particles, bends in the tubing can cause a significant increase in diffusional losses of particles smaller than 5 nm or of condensing vapor, such as sulfuric acid. Here, the effects of 90° bends with various curvatures (dimensionless curvatures of 1.3−67) on the diffusional losses in a wide range of Reynolds (25−10000) and Schmidt (0.48−1400) numbers were simulated using computational fluid dynamics. The results were parametrized to output the functions for the penetration efficiencies of a bend.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Research group: The Instrumentation, Emissions, and Atmospheric Aerosols Group
Contributors: Olin, M., Dal Maso, M.
Number of pages: 10
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: Journal of Aerosol Science
Volume: 150
Article number: 105618
ISSN (Print): 0021-8502
Original language: English
ASJC Scopus subject areas: Environmental Engineering, Pollution, Mechanical Engineering, Fluid Flow and Transfer Processes, Atmospheric Science
Keywords: Bend, Diffusion, Nanocluster, Sulfuric acid
Source: Scopus
Source ID: 85087771556

Research output: Contribution to journalArticleScientificpeer-review

Kinetics and modelling of thiosulphate biotransformations by haloalkaliphilic Thioalkalivibrio versutus

Biotransformation of thiosulphate by Thioalkalivibrio versutus was studied under haloalkaline conditions (pH 10, 0.66–1.2 M Na+) using batch assays and modelling tools for possible sulphur recovery from haloalkaline industrial streams. The thiosulphate was fully biotransformed to sulphate or to sulphate and elemental sulphur at initial S2O32−-S concentrations of 25–550 mM within 10 days. The highest biotransformation rate of 2.66 mM [S2O32−-S] h−1 was obtained at initial S2O32−-S concentration of 550 mM with half saturation constant (Ks) of 54.5 mM [S2O32−-S]. At initial concentrations below 100 mM S2O32−-S, the main product was sulphate whilst at above 100 mM also elemental sulphur was produced with up to 29% efficiency. The model approach developed incorporated S2O32− biotransformation to SO42− and S0. The kinetic modelling results were compatible (R2 > 0.90) with the experimental data. The maximum growth rate (µm) was 0.048 h−1 (0.47 mM C5H7NO2 h−1) and the maximum growth yield 0.18 mM C5H7NO2/mM S2O32−-S (20 g cell/mol S2O32−-S). The high rate thiosulphate biotransformation and elemental sulphur recovery results together with the developed kinetic model can be used for bioprocess design and operation. The potential industrial applications would aim at sustainable resource recovery from industrial haloalkaline and sulphurous process and/or effluent streams.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Bio- and Circular Economy, Yildiz Technical University
Contributors: Hajdu-Rahkama, R., Özkaya, B., Lakaniemi, A. M., Puhakka, J. A.
Number of pages: 9
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: Chemical Engineering Journal
Volume: 401
Article number: 126047
ISSN (Print): 1385-8947
Original language: English
ASJC Scopus subject areas: Chemistry(all), Environmental Chemistry, Chemical Engineering(all), Industrial and Manufacturing Engineering
Keywords: Haloalkaliphilic sulfur oxidizing bacteria, Kinetics, Resource recovery, Sulfur disproportionation, Thioalkalivibrio versutus, Thiosulfate biotransformation

Bibliographical note

INT=msee,"Özkaya, Bestamin"

Source: Scopus
Source ID: 85087487287

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
Ratings: 
  • Scopus rating (2019): CiteScore 12.8 SJR 2.43 SNIP 2.012
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

Transcription closed and open complex formation coordinate expression of genes with a shared promoter region

Many genes are spaced closely, allowing coordination without explicit control through shared regulatory elements and molecular interactions. We study the dynamics of a stochastic model of a gene-pair in a head-to-head configuration, sharing promoter elements, which accounts for the rate-limiting steps in transcription initiation. We find that only in specific regions of the parameter space of the rate-limiting steps is orderly coexpression exhibited, suggesting that successful cooperation between closely spaced genes requires the coevolution of compatible rate-limiting step configuration. The model predictions are validated using in vivo single-cell, single-RNA measurements of the dynamics of pairs of genes sharing promoter elements. Our results suggest that, in E. coli, the kinetics of the rate-limiting steps in active transcription can play a central role in shaping the dynamics of gene-pairs sharing promoter elements.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: BioMediTech, Research group: Laboratory of Biosystem Dynamics-LBD
Contributors: Häkkinen, A., Oliveira, S. M., Neeli-Venkata, R., Ribeiro, A. S.
Number of pages: 11
Publication date: 1 Dec 2019
Peer-reviewed: Yes

Publication information

Journal: Journal of the Royal Society Interface
Volume: 16
Issue number: 161
Article number: 20190507
ISSN (Print): 1742-5689
Ratings: 
  • Scopus rating (2019): CiteScore 5.7 SJR 1.694 SNIP 1.411
Original language: English
ASJC Scopus subject areas: Biotechnology, Biophysics, Bioengineering, Biomaterials, Biochemistry, Biomedical Engineering
Keywords: Bidirectional promoter, Gene expression noise, Transcription
Source: Scopus
Source ID: 85076351347

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
Ratings: 
  • Scopus rating (2019): CiteScore 6.3 SJR 0.879 SNIP 1.18
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

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
Ratings: 
  • Scopus rating (2019): CiteScore 24.8 SJR 6.976 SNIP 2.682
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
Ratings: 
  • Scopus rating (2019): CiteScore 15.2 SJR 2.315 SNIP 2.177
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

Multiresonant High-Q Plasmonic Metasurfaces

Resonant metasurfaces are devices composed of nanostructured subwavelength scatterers that generate narrow optical resonances, enabling applications in filtering, nonlinear optics, and molecular fingerprinting. It is highly desirable for these applications to incorporate such devices with multiple high-quality-factor resonances; however, it can be challenging to obtain more than a pair of narrow resonances in a single plasmonic surface. Here, we demonstrate a multiresonant metasurface that operates by extending the functionality of surface lattice resonances, which are the collective responses of arrays of metallic nanoparticles. This device features a series of resonances with high-quality factors (Q ∼ 40), an order of magnitude larger than what is typically achievable with plasmonic nanoparticles, as well as a narrow free spectral range. This design methodology can be used to better tailor the transmission spectrum of resonant metasurfaces and represents an important step toward the miniaturization of optical devices.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Research group: Nonlinear Optics, Iridian Spectral Technologies, University of Rochester Institute of Optics
Contributors: Reshef, O., Saad-Bin-Alam, M., Huttunen, M. J., Carlow, G., Sullivan, B. T., Ménard, J. M., Dolgaleva, K., Boyd, R. W.
Number of pages: 6
Pages: 6429-6434
Publication date: 11 Sep 2019
Peer-reviewed: Yes

Publication information

Journal: Nano Letters
Volume: 19
Issue number: 9
ISSN (Print): 1530-6984
Ratings: 
  • Scopus rating (2019): CiteScore 20.5 SJR 5.786 SNIP 2.271
Original language: English
ASJC Scopus subject areas: Bioengineering, Chemistry(all), Materials Science(all), Condensed Matter Physics, Mechanical Engineering
Keywords: gold nanoparticles, nanophotonics, Plasmonics, resonant metasurface, surface lattice resonance
Source: Scopus
Source ID: 85072133592

Research output: Contribution to journalArticleScientificpeer-review

Shedding frequency in cavitation erosion evolution tracking

Cavitation erosion is a concern for most hydraulic machinery. An especially damaging type of cavitation is cloud cavitation. This type of cavitation is characterized by a growth-collapse cycle in which a group of vapor bubbles first grows together in a low-pressure region and then collapses almost simultaneously when the pressure recovers. Measuring the frequency of these collapse events is possible by acoustic emission (AE), as demonstrated in this study, in which a cavitation tunnel is utilized to create cloud cavitation in the vicinity of a sample surface. These samples were equipped with AE sensors, and the initially high frequency AE signal was demodulated to detect the relatively low frequency cloud cavitation shedding. It was found that when the cavitation number is increased, AE successfully detects the changes in this frequency, confirmed by comparing the results to video analysis and to simulations from literature. Additionally, the frequency increases when cavitation erosion progresses, thus providing means to track the erosion stage. It is concluded that the presented method is suitable for both detecting the transition from cloud to sheet cavitation and the erosion evolution in the experimental cavitation tunnel. The method could probably be extended to non-intrusive hydraulic machine monitoring, as this type of cloud cavitation is common in hydrofoils.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Automation Technology and Mechanical Engineering, Materials Science and Environmental Engineering, Université Grenoble Alpes
Contributors: Ylönen, M., Franc, J. P., Miettinen, J., Saarenrinne, P., Fivel, M.
Number of pages: 9
Pages: 141-149
Publication date: 1 Sep 2019
Peer-reviewed: Yes

Publication information

Journal: International Journal of Multiphase Flow
Volume: 118
ISSN (Print): 0301-9322
Ratings: 
  • Scopus rating (2019): CiteScore 5.1 SJR 1.18 SNIP 1.829
Original language: English
ASJC Scopus subject areas: Mechanical Engineering, Physics and Astronomy(all), Fluid Flow and Transfer Processes
Keywords: Acoustic emission, Cavitation erosion, Cloud cavitation, Shedding frequency
Source: Scopus
Source ID: 85067547906

Research output: Contribution to journalArticleScientificpeer-review

Influence of ions to modulate hydrazone and oxime reaction kinetics to obtain dynamically cross-linked hyaluronic acid hydrogels

Dynamic covalent chemistry forming hydrazone and oxime linkages is attractive due to its simplicity, selectivity and compatibility under aqueous conditions. However, the low reaction rate at physiological pH hampers its use in biomedical applications. Herein, we present different monovalent and bivalent aqueous salt solutions as bio-friendly, non-toxic catalysts which can drive the hydrazone and oxime reactions with excellent efficacy at physiological pH. Direct comparison of hydrazone and oxime reactions using a small molecule model, without any salt catalysis, indicated that oxime formation is 6-times faster than hydrazone formation. Addition of different salts (NaCl, NaBr, KCl, LiCl, LiClO4, Na2SO4, MgCl2 and CaCl2) accelerated the pseudo-first-order reaction kinetics by ∼1.2-4.9-fold for acylhydrazone formation and by ∼1.5-6.9-fold for oxime formation, in a concentration-dependent manner. We further explored the potential of such catalysts to develop acylhydrazone and oxime cross-linked hyaluronic acid (HA) hydrogels with different physicochemical properties without changing the degree of chemical modification. Analogous to the small molecule model system, the addition of monovalent and divalent salts as catalysts significantly reduced the gelling time. The gelling time for the acylhydrazone cross-linked HA-hydrogel (1.6 wt%) could be reduced from 300 min to 1.2 min by adding 100 mM CaCl2, while that for the oxime cross-linked HA-hydrogel (1.2 wt%) could be reduced from 68 min to 1.1 min by adding 50 mM CaCl2. This difference in the gelling time also resulted in hydrogels with differential swelling properties as measured after 24 h. Our results are the first to demonstrate the use of salts, for catalyzing hydrogel formation under physiologically relevant conditions.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: BioMediTech, Research group: Biomaterials and Tissue Engineering Group, University of Montreal, Uppsala University
Contributors: Wang, S., Nawale, G. N., Oommen, O. P., Hilborn, J., Varghese, O. P.
Number of pages: 6
Pages: 4322-4327
Publication date: 21 Aug 2019
Peer-reviewed: Yes

Publication information

Journal: Polymer Chemistry
Volume: 10
Issue number: 31
ISSN (Print): 1759-9954
Ratings: 
  • Scopus rating (2019): CiteScore 9 SJR 1.459 SNIP 1.057
Original language: English
ASJC Scopus subject areas: Bioengineering, Biochemistry, Polymers and Plastics, Organic Chemistry
Electronic versions: 
Source: Scopus
Source ID: 85070404630

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
Ratings: 
  • Scopus rating (2019): CiteScore 10.7 SJR 1.971 SNIP 2.654
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

Characterisation and in vitro and in vivo evaluation of supercritical-CO2-foamed β-TCP/PLCL composites for bone applications

Most synthetic bone grafts are either hard and brittle ceramics or paste-like materials that differ in applicability from the gold standard autologous bone graft, which restricts their widespread use. Therefore, the aim of the study was to develop an elastic, highly porous and biodegradable β-tricalciumphosphate/poly(L-lactide-co-ε-caprolactone) (β-TCP/PLCL) composite for bone applications using supercritical CO2 foaming. Ability to support osteogenic differentiation was tested in human adipose stem cell (hASC) culture for 21 d. Biocompatibility was evaluated for 24 weeks in a rabbit femur-defect model. Foamed composites had a high ceramic content (50 wt%) and porosity (65-67 %). After 50 % compression, in an aqueous environment at 37 °C, tested samples returned to 95 % of their original height. Hydrolytic degradation of β-TCP/PLCL composite, during the 24-week follow-up, was very similar to that of porous PLCL scaffold both in vitro and in vivo. Osteogenic differentiation of hASCs was demonstrated by alkaline phosphatase activity analysis, alizarin red staining, soluble collagen analysis, immunocytochemical staining and qRT-PCR. In vitro, hASCs formed a pronounced mineralised collagen matrix. A rabbit femur defect model confirmed biocompatibility of the composite. According to histological Masson-Goldner's trichrome staining and micro-computed tomography, β-TCP/PLCL composite did not elicit infection, formation of fibrous capsule or cysts. Finally, native bone tissue at 4 weeks was already able to grow on and in the β-TCP/PLCL composite. The elastic and highly porous β-TCP/PLCL composite is a promising bone substitute because it is osteoconductive and easy-to-use and mould intraoperatively.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: BioMediTech
Contributors: Pitkänen, S., Paakinaho, K., Pihlman, H., Ahola, N., Hannula, M., Asikainen, S., Manninen, M., Morelius, M., Keränen, P., Hyttinen, J., Kellomäki, M., Laitinen-Vapaavuori, O., Miettinen, S.
Number of pages: 16
Pages: 35-50
Publication date: 5 Aug 2019
Peer-reviewed: Yes

Publication information

Journal: European cells & materials
Volume: 38
ISSN (Print): 1473-2262
Ratings: 
  • Scopus rating (2019): CiteScore 6 SJR 1.141 SNIP 1.069
Original language: English
ASJC Scopus subject areas: Bioengineering, Biochemistry, Biomaterials, Biomedical Engineering, Cell Biology
Electronic versions: 
Source: Scopus
Source ID: 85071152630

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
Ratings: 
  • Scopus rating (2019): CiteScore 5.2 SJR 0.624 SNIP 0.822
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

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
Ratings: 
  • Scopus rating (2019): CiteScore 7.1 SJR 1.191 SNIP 1.139
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

Observation of Coexistence of Yu-Shiba-Rusinov States and Spin-Flip Excitations

We investigate the spectral evolution in different metal phthalocyanine molecules on NbSe2 surface using scanning tunnelling microscopy (STM) as a function of the coupling with the substrate. For manganese phthalocyanine (MnPc), we demonstrate a smooth spectral crossover from Yu-Shiba-Rusinov (YSR) bound states to spin-flip excitations. This has not been observed previously and it is in contrast to simple theoretical expectations. We corroborate the experimental findings using numerical renormalization group calculations. Our results provide fundamental new insight on the behavior of atomic scale magnetic/SC hybrid systems, which is important, for example, for engineered topological superconductors and spin logic devices.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Aalto University, Jozef Stefan Institute, University of Ljubljana
Contributors: Kezilebieke, S., Žitko, R., Dvorak, M., Ojanen, T., Liljeroth, P.
Number of pages: 6
Pages: 4614-4619
Publication date: 10 Jul 2019
Peer-reviewed: Yes

Publication information

Journal: Nano Letters
Volume: 19
Issue number: 7
ISSN (Print): 1530-6984
Ratings: 
  • Scopus rating (2019): CiteScore 20.5 SJR 5.786 SNIP 2.271
Original language: English
ASJC Scopus subject areas: Bioengineering, Chemistry(all), Materials Science(all), Condensed Matter Physics, Mechanical Engineering
Keywords: Magnetic impurity, scanning tunneling microscopy (STM), spin-flip excitation, superconductor, Yu-Shiba-Rusinov state
Electronic versions: 
Source: Scopus
Source ID: 85069329661

Research output: Contribution to journalArticleScientificpeer-review

An architectural understanding of natural sway frequencies in trees

The relationship between form and function in trees is the subject of a longstanding debate in forest ecology and provides the basis for theories concerning forest ecosystem structure and metabolism. Trees interact with the wind in a dynamic manner and exhibit natural sway frequencies and damping processes that are important in understanding wind damage. Tree-wind dynamics are related to tree architecture, but this relationship is not well understood. We present a comprehensive view of natural sway frequencies in trees by compiling a dataset of field measurement spanning conifers and broadleaves, tropical and temperate forests. The field data show that a cantilever beam approximation adequately predicts the fundamental frequency of conifers, but not that of broadleaf trees. We also use structurally detailed tree dynamics simulations to test fundamental assumptions underpinning models of natural frequencies in trees. We model the dynamic properties of greater than 1000 trees using a finite-element approach based on accurate three-dimensional model trees derived from terrestrial laser scanning data. We show that (1) residual variation, the variation not explained by the cantilever beam approximation, in fundamental frequencies of broadleaf trees is driven by their architecture; (2) slender trees behave like a simple pendulum, with a single natural frequency dominating their motion, which makes them vulnerable to wind damage and (3) the presence of leaves decreases both the fundamental frequency and the damping ratio. These findings demonstrate the value of new three-dimensional measurements for understanding wind impacts on trees and suggest new directions for improving our understanding of tree dynamics from conifer plantations to natural forests.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Computing Sciences, University of Oxford, SCION, University of Connecticut, Delft University of Technology, Wageningen University and Research Centre, University of Massachusetts Amherst, National Parks Board, University of Melbourne, Oregon State University, Universiteit Gent, National Physical Laboratory, University College London, NERC National Centre for Earth Observation (NCEO), 16 Center for International Forestry Research (CIFOR), Swedish University of Agricultural Sciences, INRA
Contributors: Jackson, T., Shenkin, A., Moore, J., Bunce, A., van Emmerik, T., Kane, B., Burcham, D., James, K., Selker, J., Calders, K., Origo, N., Disney, M., Burt, A., Wilkes, P., Raumonen, P., Gonzalez de Tanago Menaca, J., Lau, A., Herold, M., Goodman, R. C., Fourcaud, T., Malhi, Y.
Number of pages: 1
Publication date: 28 Jun 2019
Peer-reviewed: Yes

Publication information

Journal: Journal of the Royal Society. Interface
Volume: 16
Issue number: 155
ISSN (Print): 1742-5689
Ratings: 
  • Scopus rating (2019): CiteScore 5.7 SJR 1.694 SNIP 1.411
Original language: English
ASJC Scopus subject areas: Biotechnology, Biophysics, Bioengineering, Biomaterials, Biochemistry, Biomedical Engineering
Keywords: finite-element analysis, fundamental frequency, natural frequencies, terrestrial laser scanning, tree architecture, wind damage
Source: Scopus
Source ID: 85067464325

Research output: Contribution to journalArticleScientificpeer-review

Tailoring Second-Harmonic Emission from (111)-GaAs Nanoantennas

Second-harmonic generation (SHG) in resonant dielectric Mie-scattering nanoparticles has been hailed as a powerful platform for nonlinear light sources. While bulk-SHG is suppressed in elemental semiconductors, for example, silicon and germanium due to their centrosymmetry, the group of zincblende III-V compound semiconductors, especially (100)-grown AlGaAs and GaAs, have recently been presented as promising alternatives. However, major obstacles to push the technology toward practical applications are the limited control over directionality of the SH emission and especially zero forward/backward radiation, resulting from the peculiar nature of the second-order nonlinear susceptibility of this otherwise highly promising group of semiconductors. Furthermore, the generated SH signal for (100)-GaAs nanoparticles depends strongly on the polarization of the pump. In this work, we provide both theoretically and experimentally a solution to these problems by presenting the first SHG nanoantennas made from (111)-GaAs embedded in a low index material. These nanoantennas show superior forward directionality compared to their (100)-counterparts. Most importantly, based on the special symmetry of the crystalline structure, it is possible to manipulate the SHG radiation pattern of the nanoantennas by changing the pump polarization without affecting the linear properties and the total nonlinear conversion efficiency, hence paving the way for efficient and flexible nonlinear beam-shaping devices.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Nonlinear Optics, Physics, Australian National University, Friedrich-Schiller-University Jena, School of Engineering and Information Technology, University of New South Wales (UNSW) Australia, Russian Academy of Sciences
Contributors: Sautter, J. D., Xu, L., Miroshnichenko, A. E., Lysevych, M., Volkovskaya, I., Smirnova, D. A., Camacho-Morales, R., Zangeneh Kamali, K., Karouta, F., Vora, K., Tan, H. H., Kauranen, M., Staude, I., Jagadish, C., Neshev, D. N., Rahmani, M.
Number of pages: 7
Pages: 3905-3911
Publication date: 12 Jun 2019
Peer-reviewed: Yes

Publication information

Journal: Nano Letters
Volume: 19
Issue number: 6
ISSN (Print): 1530-6984
Ratings: 
  • Scopus rating (2019): CiteScore 20.5 SJR 5.786 SNIP 2.271
Original language: English
ASJC Scopus subject areas: Bioengineering, Chemistry(all), Materials Science(all), Condensed Matter Physics, Mechanical Engineering
Keywords: Dielectric nanoantennas, directional emission, III-V semiconductors, Mie resonance, multipolar interference, second harmonic generation
Source: Scopus
Source ID: 85067057047

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
Ratings: 
  • Scopus rating (2019): CiteScore 7.4 SJR 1.356 SNIP 1.308
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

Mining tailings as raw materials for reaction-sintered aluminosilicate ceramics: Effect of mineralogical composition on microstructure and properties

This paper presents studies on the utilization of aluminosilicate-based mining tailings as raw materials for mullite-based ceramics. Based on the 3:2 stoichiometric composition, mullite was synthesised by reactive sintering with a series of powder mixtures with alumina additions. X-ray diffractometry and scanning electron microscopy analyses revealed that, at the specific mineralogical composition, mullite structure formed surrounded by an amorphous glass phase in reaction-sintered powder mixtures. Results demonstrated that the chemical and mineralogical composition of mining tailings do have an effect on mullite formation possibilities and, only with the particular mineralogical composition, the mullite formation is possible regardless of the correct Al:Si ratio in tailings. Physical and mechanical properties of the formed ceramics were defined, showing comparable values to 3:2 mullite reference. Mullite structure formation enables a better thermal resistance up to above 1450 °C of the formed tailings-based ceramics compared to other aluminosilicates, reflecting their utilization potential for refractory ceramic applications.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science, Research group: Materials Characterization, VTT Technical Research Centre of Finland, Geologian tutkimuskeskus
Contributors: Karhu, M., Lagerbom, J., Solismaa, S., Honkanen, M., Ismailov, A., Räisänen, M. L., Huttunen-Saarivirta, E., Levänen, E., Kivikytö-Reponen, P.
Pages: 4840-4848
Publication date: Mar 2019
Peer-reviewed: Yes
Early online date: 2018

Publication information

Journal: Ceramics International
Volume: 45
Issue number: 4
ISSN (Print): 0272-8842
Ratings: 
  • Scopus rating (2019): CiteScore 6.1 SJR 0.891 SNIP 1.31
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Ceramics and Composites, Process Chemistry and Technology, Surfaces, Coatings and Films, Materials Chemistry
Keywords: Mining tailings, Mullite, Reaction sintering, Refractory ceramics, Utilization

Bibliographical note

EXT="Lagerbom, Juha"

Source: Scopus
Source ID: 85057276435

Research output: Contribution to journalArticleScientificpeer-review

Solvent Welding and Imprinting Cellulose Nanofiber Films Using Ionic Liquids

Cellulose nanofiber films (CNFF) were treated via a welding process using ionic liquids (ILs). Acid-base-conjugated ILs derived from 1,5-diazabicyclo[4.3.0]non-5-ene [DBN] and 1-ethyl-3-methylimidazolium acetate ([emim][OAc]) were utilized. The removal efficiency of ILs from welded CNFF was assessed using liquid-state nuclear magnetic resonance (NMR) spectroscopy and Fourier transform infrared spectroscopy (FTIR). The mechanical and physical properties of CNFF indicated surface plasticization of CNFF, which improved transparency. Upon treatment, the average CNFF toughness increased by 27%, and the films reached a Young's modulus of ∼5.8 GPa. These first attempts for IL "welding" show promise to tune the surfaces of biobased films, expanding the scope of properties for the production of new biobased materials in a green chemistry context. The results of this work are highly relevant to the fabrication of CNFFs using ionic liquids and related solvents.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science, Research group: Paper Converting and Packaging, Universidad Del Bío-Bío, Aalto University
Contributors: Reyes, G., Borghei, M., King, A. W. T., Lahti, J., Rojas, O. J.
Pages: 502-514
Publication date: 14 Jan 2019
Peer-reviewed: Yes
Early online date: 12 Dec 2018

Publication information

Journal: Biomacromolecules
Volume: 20
Issue number: 1
ISSN (Print): 1525-7797
Ratings: 
  • Scopus rating (2019): CiteScore 10 SJR 1.61 SNIP 1.276
Original language: English
ASJC Scopus subject areas: Bioengineering, Biomaterials, Polymers and Plastics, Materials Chemistry
Source: Scopus
Source ID: 85059629357

Research output: Contribution to journalArticleScientificpeer-review

Kinetics and thermochemistry of the reaction of 3-methylpropargyl radical with molecular oxygen

We have measured the kinetics and thermochemistry of the reaction of 3-methylpropargyl radical (but-2-yn-1-yl) with molecular oxygen over temperature (223-681 K) and bath gas density ( 1.2-15.0×1016 cm-3 ) ranges employing photoionization mass-spectrometry. At low temperatures (223-304 K), the reaction proceeds overwhelmingly by a simple addition reaction to the -CH2 end of the radical, and the measured CH3CCCH2•+O2 reaction rate coefficient shows negative temperature dependence and depends on bath gas density. At intermediate temperatures (340-395 K), the addition reaction equilibrates and the equilibrium constant was determined at different temperatures. At high temperatures (465-681 K), the kinetics is governed by O2 addition to the third carbon atom of the radical, and rate coefficient measurements were again possible. The high temperature CH3CCCH2•+O2 rate coefficient is much smaller than at low T, shows positive temperature dependence, and is independent of bath gas density. In the intermediate and high temperature ranges, we observe a formation signal for ketene (ethenone). The reaction was further investigated by combining the experimental results with quantum chemical calculations and master equation modeling. By making small adjustments ( 2-3kJmol-1 ) to the energies of two key transition states, the model reproduces the experimental results within uncertainties. The experimentally constrained master equation model was used to simulate the CH3CCCH2•+O2 reaction system at temperatures and pressures relevant to combustion.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: University of Helsinki, Hungarian Academy of Sciences
Contributors: Pekkanen, T. T., Timonen, R. S., Lendvay, G., Rissanen, M. P., Eskola, A. J.
Number of pages: 8
Pages: 299-306
Publication date: 1 Jan 2019
Peer-reviewed: Yes

Publication information

Journal: PROCEEDINGS OF THE COMBUSTION INSTITUTE
Volume: 37
Issue number: 1
ISSN (Print): 1540-7489
Ratings: 
  • Scopus rating (2019): CiteScore 6.5 SJR 2.116 SNIP 2.449
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Mechanical Engineering, Physical and Theoretical Chemistry
Keywords: Ab initio quantum chemistry, Combustion chemistry, Experimental gas kinetics, Master equation modeling, Propargyl radical
Source: Scopus
Source ID: 85049566548

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
Ratings: 
  • Scopus rating (2019): CiteScore 20.8 SJR 5.438 SNIP 2.254
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

Cost-optimal energy performance measures in a new daycare building in cold climate

New municipal service buildings must be energy effective, and cost-optimality is one of the criteria for selecting the suitable energy performance improvement measures. A daycare building in a cold climate was studied by means of simulation-based, multi-objective optimisation. Using a genetic algorithm, both target energy use and life-cycle cost of the selected measures were minimised. It was found that extensive insulation of the building envelope is not a cost-optimal method to reduce the daycare building energy use. Improving energy efficiency of the ventilation system, utilising solar energy on-site and employing a light control strategy are preferable ways of improving the building energy performance. Ground-source heat pump is a more cost-optimal heating system for the daycare building than district heating. The cost-optimal sizing of the heat pump is small, only 28% of the required maximum heating power. Abbreviations: AHU: air handling unit; CAV: constant air volume; COMBI: comprehensive development of nearly zero-energy municipal service buildings; COP: coefficient of performance; DH: district heating; DHW: domestic hot water; EPBD: energy performance of buildings directive; EU: European Union; FINVAC: Finnish Association of HVAC Societies; GSHP: ground-source heat pump; HRU: heat recovery unit; IDA ICE: IDA Indoor Climate and Energy; LED: light-emitting diode; MOBO: multi-objective building optimisation tool; NSGA-II: Non-dominated Sorting Genetic Algorithm II; nZEB: nearly zero-energy building; PV: photovoltaic; TRY: test reference year; VAV: variable air volume; ZEB: zero-energy building

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Civil Engineering, Equa Simulation Finland Oy, Aalto University, Sweco Finland Oy
Contributors: Sankelo, P., Jokisalo, J., Nyman, J., Vinha, J., Sirén, K.
Number of pages: 19
Pages: 104-122
Publication date: 2019
Peer-reviewed: Yes
Early online date: 15 Mar 2018

Publication information

Journal: International Journal of Sustainable Energy
Volume: 38
Issue number: 2
ISSN (Print): 1478-6451
Ratings: 
  • Scopus rating (2019): CiteScore 3 SJR 0.427 SNIP 0.595
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Fuel Technology, Energy(all), Process Chemistry and Technology, Fluid Flow and Transfer Processes
Keywords: Building simulation, daycare building, life-cycle cost, multi-objective optimisation, simulation-based optimisation, target energy use
URLs: 
Source: Scopus
Source ID: 85043677926

Research output: Contribution to journalArticleScientificpeer-review

Textile-integrated three-dimensional printed and embroidered structures for wearable wireless platforms

In this paper, we present fabrication and performance evaluation of three-dimensional (3D) printed and embroidered textile-integrated passive ultra high frequency radio frequency identification (RFID) platforms. The antennas were manufactured by 3D printing a stretchable silver conductor directly on an elastic band. The electric and mechanical joint between the 3D printed antennas and microchips was formed by gluing with conductive epoxy glue, by printing the antenna directly on top of the microchip structure, and by embroidering with conductive yarn. Initially, all types of fabricated RFID tags achieved read ranges of 8–9 meters. Next, the components were tested for wetting as well as for harsh cyclic strain and bending. The immersing and cyclic bending slightly affected the performance of the tags. However, they did not stop the tags from working in an acceptable way, nor did they have any permanent effect. The epoxy-glued or 3D printed antenna–microchip interconnections were not able to endure harsh stretching. On the other hand, the tags with the embroidered antenna–microchip interconnections showed excellent wireless performance, both during and after a 100 strong stretching cycles. Thus, the novel approach of combining 3D printing and embroidery seems to be a promising way to fabricate textile-integrated wireless platforms.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Faculty of Biomedical Sciences and Engineering, Research group: Wireless Identification and Sensing Systems Research Group
Contributors: He, H., Chen, X., Ukkonen, L., Virkki, J.
Publication date: 2019
Peer-reviewed: Yes
Early online date: 1 Jan 2018

Publication information

Journal: Textile Research Journal
Volume: 89
Issue number: 4
ISSN (Print): 0040-5175
Ratings: 
  • Scopus rating (2019): CiteScore 2.6 SJR 0.462 SNIP 1.44
Original language: English
ASJC Scopus subject areas: Chemical Engineering (miscellaneous), Polymers and Plastics
Keywords: antennas, embroidery, interconnections, passive ultra high frequency radio frequency identification, stretchable electronics, textile-integrated electronics, three-dimensional printing, wearable platforms
Source: Scopus
Source ID: 85045101109

Research output: Contribution to journalArticleScientificpeer-review

Reliability evaluation of wearable radio frequency identification tags: Design and fabrication of a two-part textile antenna

Passive radio frequency identification-based technology is a convincing approach to the achievement of versatile energy- and cost-efficient wireless platforms for future wearable applications. By using two-part antenna structures, the antenna-electronics interconnections can remain non-stressed, which can significantly improve the reliability of the textile-embedded wireless components. In this article, we describe fabrication of two-part stretchable and non-stretchable passive ultra-high frequency radio frequency identification textile tags using electro-textile and embroidered antennas, and test their reliability when immersed as well as under cyclic strain. The results are compared to tags with traditional one-part dipole antennas fabricated from electro-textiles and by embroidery. Based on the results achieved, the initial read ranges of the two-part antenna tags, around 5 m, were only slightly shorter than those of the one-part antenna tags. In addition, the tag with two-part antennas can maintain high performance in a moist environment and during continuous stretching, unlike the one-part antenna tag where the antenna-integrated circuit attachment is under stress.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Faculty of Biomedical Sciences and Engineering, Research group: Wireless Identification and Sensing Systems Research Group
Contributors: Chen, X., Ukkonen, L., Virkki, J.
Publication date: 2019
Peer-reviewed: Yes
Early online date: 1 Jan 2018

Publication information

Journal: Textile Research Journal
Volume: 89
Issue number: 4
ISSN (Print): 0040-5175
Ratings: 
  • Scopus rating (2019): CiteScore 2.6 SJR 0.462 SNIP 1.44
Original language: English
ASJC Scopus subject areas: Chemical Engineering (miscellaneous), Polymers and Plastics
Keywords: E-textile antenna, embroidery antenna, radio frequency identification
Source: Scopus
Source ID: 85045121603

Research output: Contribution to journalArticleScientificpeer-review

Towards the EU emissions targets of 2050: optimal energy renovation measures of Finnish apartment buildings

Member countries of the European Union have released targets to reduce carbon dioxide emissions by 80% by the year 2050. Energy use in buildings is a major source of these emissions, which is why this study focused on the cost-optimal renovation of Finnish apartment buildings. Apartment buildings from four different construction years (pre-1976, 1976–2002, 2003–2009 and post-2010) were modelled, using three different heating systems: district heating, ground-source heat pump and exhaust air heat pump. Multi-objective optimisation was utilised to find the most cost-effective energy renovation measures. Most cost-effective renovation measures were ground-source heat pumps, demand-based ventilation and solar electricity. Additional thermal insulation of walls was usually too expensive. By performing only the cost-effective renovations, the emissions could be reduced by 80%, 82%, 69% and 68%, from the oldest to the newest buildings, respectively. This could be done with the initial investment cost of 296, 235, 115 and 104 €/m2, respectively.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Civil Engineering, Aalto University, Nanjing Tech University
Contributors: Hirvonen, J., Jokisalo, J., Heljo, J., Kosonen, R.
Publication date: 2019
Peer-reviewed: Yes
Early online date: 2018

Publication information

Journal: International Journal of Sustainable Energy
Volume: 38
Issue number: 7
ISSN (Print): 1478-6451
Ratings: 
  • Scopus rating (2019): CiteScore 3 SJR 0.427 SNIP 0.595
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Fuel Technology, Energy(all), Process Chemistry and Technology, Fluid Flow and Transfer Processes
Keywords: apartment building, Cost-optimal renovation, energy performance, greenhouse gas emissions, multi-objective optimisation
Source: Scopus
Source ID: 85058681434

Research output: Contribution to journalArticleScientificpeer-review

Effect of apartment building energy renovation on hourly power demand

Optimal energy renovations of apartment buildings in Finland have a great impact on annual energy demand. However, reduction of energy demand does not necessarily translate into similar changes in peak power demand. Four different types of apartment buildings, representing the Finnish apartment building stock, were examined after optimal energy retrofits to see the influence of retrofitting on hourly power demand. Switching from district heating to ground-source heat pumps reduced emissions significantly under current energy mix. However, the use of ground-source heat pumps increased hourly peak electricity demand by 46–153%, compared to district heated apartment buildings. The corresponding increase in electrical energy demand was 30–108% in the peak month of January. This could increase the use of high emission peak power plants and negate some of the emission benefits. Solar thermal collectors and heat recovery systems could reduce purchased heating energy to zero in summer. Solar electricity could reduce median power demand in summer, but had only a little effect on peak power demand. The reduction in peak power demand after energy retrofits was less than the reduction in energy demand.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Civil Engineering, Aalto University, Nanjing Tech University
Contributors: Hirvonen, J., Jokisalo, J., Heljo, J., Kosonen, R.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: International Journal of Sustainable Energy
ISSN (Print): 1478-6451
Ratings: 
  • Scopus rating (2019): CiteScore 3 SJR 0.427 SNIP 0.595
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Fuel Technology, Energy(all), Process Chemistry and Technology, Fluid Flow and Transfer Processes
Keywords: apartment building, district heating, energy performance, Energy retrofits, greenhouse gas emissions, power demand
Source: Scopus
Source ID: 85065643393

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
Ratings: 
  • Scopus rating (2019): CiteScore 2.6 SJR 0.374 SNIP 0.66
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

Quality and Capacity Analysis of Molecular Communications in Bacterial Synthetic Logic Circuits

Synthetic logic circuits have been proposed as potential solutions for theranostics of biotechnological problems. One proposed model is the engineering of bacteria cells to create logic gates, and the communication between the bacteria populations will enable the circuit operation. In this paper, we analyse the quality of bacteria-based synthetic logic circuit through molecular communications that represent communication along a bus between three gates. In the bacteria-based synthetic logic circuit, the system receives environmental signals as molecular inputs and will process this information through a cascade of synthetic logic gates and free diffusion channels. We analyse the performance of this circuit by evaluating its quality and its relationship to the channel capacity of the molecular communications links that interconnect the bacteria populations. Our results show the effect of the molecular environmental delay and molecular amplitude differences over both the channel capacity and circuit quality. Furthermore, based on these metrics we also obtain an optimum region for the circuit operation resulting in an accuracy of 80&#x0025; for specific conditions. These results show that the performance of synthetic biology circuits can be evaluated through molecular communications, and lays the groundwork for combined systems that can contribute to future biomedical and biotechnology applications.

General information

Publication status: Accepted/In press
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Engineering, Waterford Institute of Technology
Contributors: Martins, D. P., Barros, M. T., Balasubramaniam, S.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: IEEE Transactions on Nanobioscience
ISSN (Print): 1536-1241
Ratings: 
  • Scopus rating (2019): CiteScore 5.4 SJR 0.62 SNIP 1.01
Original language: English
ASJC Scopus subject areas: Biotechnology, Bioengineering, Medicine (miscellaneous), Biomedical Engineering, Pharmaceutical Science, Computer Science Applications, Electrical and Electronic Engineering
Keywords: Engineered bacteria, Logic circuits, Logic gates, Microorganisms, Molecular communication (telecommunication), Molecular communications, Sensors, Sociology, Statistics, Synthetic logic circuits
Source: Scopus
Source ID: 85070392121

Research output: Contribution to journalArticleScientificpeer-review

High-speed production of antibacterial fabrics using liquid flame spray

Healthcare associated infections (HAIs) are known as one of the major problems of the modern healthcare system, which result in additional cost and mortality. It has also been shown that pathogenic bacteria are mostly transferred via surfaces in healthcare settings. Therefore, antibacterial surfaces, which include fabrics and textiles, can be used in a healthcare environment to reduce the transfer of pathogenic bacteria, hence reducing HAIs. Silver nanoparticles have been shown to have broad spectrum antibacterial properties, and therefore they have been incorporated into fabrics to provide antibacterial functionality. Liquid flame spray (LFS) nanoparticle synthesis allows nanoparticles to be produced and deposited on surfaces at speeds up to and beyond 300 m/min. Herein, LFS is used to deposit silver nanoparticles onto two fabrics that are commonly used in the hospital environment with the aim of producing antibacterial fabrics. A thin plasma coating on top of the fabrics after silver deposition is used to improve nanoparticle adhesion. Fabrics coated with silver nanoparticles demonstrated antibacterial properties against Escherichia coli. Nanoparticle imaging and surface chemical characterization are performed using scanning electron microscopy and X-ray photoelectron spectroscopy. The highlights of this research are as follows: • high-speed synthesis and deposition of silver nanoparticles on fabrics; • plasma coating onto fabrics with silver nanoparticles; • antibacterial fabrics for potential use in healthcare environments.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Aerosol Synthesis, Physics, Abo Akad Univ, Abo Akademi University, Dept Phys, RISE Research Institutes of Sweden AB, Turun yliopisto, University of Eastern Finland
Contributors: Brobbey, K. J., Haapanen, J., Tuominen, M., Mäkelä, J., Gunell, M., Eerola, E., Saarinen, J. J., Toivakka, M.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Textile Research Journal
ISSN (Print): 0040-5175
Ratings: 
  • Scopus rating (2019): CiteScore 2.6 SJR 0.462 SNIP 1.44
Original language: English
ASJC Scopus subject areas: Chemical Engineering (miscellaneous), Polymers and Plastics
Keywords: antibacterial, fabrics, liquid flame spray, nanoparticles, plasma deposition, silver
Source: Scopus
Source ID: 85071117647

Research output: Contribution to journalArticleScientificpeer-review

Activity Level and Body Mass Index as Predictors of Physical Workload During Working Career

The increasing prevalence of inactivity and obesity, along with aging, has implications on work capacity of labor force. This study reports the relationships between activity level and BMI by age with objectively measured physical workload. Data were examined from a sample of 19 481 Finnish employees using an estimate of minute-to-minute oxygen consumption based on R-R interval recordings. The mean estimated %VO2max during the working day was 12.1 (±3.6) and 15.1 (±4.5)% for men and women, respectively. Based on a linear model, the mean %VO2max increased by 1.5%-unit per 10-year increase in age, by 2.1%-unit per 5 kg/m2 increase in BMI, and decreased by 1.6%-unit if improving physical activity class by two (p < 0.001 for all). Overweight and obesity, together with inactivity, notably increases workload throughout the career, even though at young adulthood, the daily workload is almost the same for each person regardless of the BMI, activity level, or gender. This study highlights the importance of regular physical activity and normal weight in protecting the worker from excessive physical (cardiovascular) workload during the whole working career.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: BioMediTech, Research group: Personal Health Informatics-PHI, Tyoterveyslaitos
Contributors: Mänttäri, S. K., Oksa, J. A., Virkkala, J., Pietilä, J. A.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Safety and Health at Work
ISSN (Print): 2093-7911
Ratings: 
  • Scopus rating (2019): CiteScore 3.6 SJR 0.529 SNIP 1.996
Original language: English
ASJC Scopus subject areas: Safety, Risk, Reliability and Quality, Safety Research, Public Health, Environmental and Occupational Health, Chemical Health and Safety
Keywords: Aging worker, Big data, Functional capacity, Physical activity, Work ability
Electronic versions: 
Source: Scopus
Source ID: 85072749291

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
Ratings: 
  • Scopus rating (2019): CiteScore 10 SJR 1.61 SNIP 1.276
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

Large-scale efficient water harvesting using bioinspired micro-patterned copper oxide nanoneedle surfaces and guided droplet transport

As the Earth's atmosphere contains an abundant amount of water as vapors, a device which can capture a fraction of this water could be a cost-effective and practical way of solving the water crisis. There are many biological surfaces found in nature which display unique wettability due to the presence of hierarchical micro-nanostructures and play a major role in water deposition. Inspired by these biological microstructures, we present a large scale, facile and cost-effective method to fabricate water-harvesting functional surfaces consisting of high-density copper oxide nanoneedles. A controlled chemical oxidation approach on copper surfaces was employed to fabricate nanoneedles with controlled morphology, assisted by bisulfate ion adsorption on the surface. The fabricated surfaces with nanoneedles displayed high wettability and excellent fog harvesting capability. Furthermore, when the fabricated nanoneedles were subjected to hydrophobic coating, these were able to rapidly generate and shed coalesced droplets leading to further increase in fog harvesting efficiency. Overall, ∼99% and ∼150% increase in fog harvesting efficiency was achieved with non-coated and hydrophobic layer coated copper oxide nanoneedle surfaces respectively when compared to the control surfaces. As the transport of the harvested water is very important in any fog collection system, hydrophilic channels inspired by leaf veins were made on the surfaces via a milling technique which allowed an effective and sustainable way to transport the captured water and further enhanced the water collection efficiency by ∼9%. The system presented in this study can provide valuable insights towards the design and fabrication of fog harvesting systems, adaptable to arid or semi-arid environmental conditions.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: BioMediTech, Research group: Surface Science, Physics, Research group: Bioinspired Materials and Robotics (BMR)
Contributors: Sharma, V., Yiannacou, K., Karjalainen, M., Lahtonen, K., Valden, M., Sariola, V.
Number of pages: 16
Pages: 4025-4040
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Nanoscale Advances
Volume: 1
Issue number: 10
ISSN (Print): 2516-0230
Ratings: 
  • Scopus rating (2019): CiteScore 1
Original language: English
ASJC Scopus subject areas: Engineering(all), Bioengineering, Atomic and Molecular Physics, and Optics, Materials Science(all), Chemistry(all)
Source: Scopus
Source ID: 85073635162

Research output: Contribution to journalArticleScientificpeer-review

Mechanical impact stimulation platform tailored for high-resolution light microscopy

High frequency (HF) mechanical vibration has been used in vitro to study the cellular response to mechanical stimulation and induce stem cell differentiation. However, detailed understanding of the effect of the mechanical cues on cellular physiology is lacking. To meet this limitation, we have designed a system, which enables monitoring of living cells by high-resolution light microscopy during mechanical stimulation by HF vibration or mechanical impacts. The system consists of a commercial speaker, and a 3D printed sample vehicle and frame. The speaker moves the sample in the horizontal plane, allowing simultaneous microscopy. The HF vibration (30–200 Hz) performances of two vehicles made of polymer and aluminum were characterized with accelerometer. The mechanical impacts were characterized by measuring the acceleration of the aluminum vehicle and by time lapse imaging. The lighter polymer vehicle produced higher HF vibration magnitudes at 30–50 Hz frequencies than the aluminum vehicle. However, the aluminum vehicle performed better at higher frequencies (60–70 Hz, 90–100 Hz, 150 Hz). Compatibility of the system in live cell experiments was investigated with epithelial cells (MDCKII, expressing Emerald-Occludin) and HF (0.56 Gpeak, 30 Hz and 60 Hz) vibration. Our findings indicated that our system is compatible with high-resolution live cell microscopy. Furthermore, the epithelial cells were remarkable stable under mechanical vibration stimulation. To conclude, we have designed an inexpensive tool for the studies of cellular biophysics, which combines versatile in vivo like mechanical stimuli with live cell imaging, showing a great potential for several cellular applications.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: BioMediTech, Research group: Computational Biophysics and Imaging Group
Contributors: Halonen, H. T., Hyttinen, J. A., Ihalainen, T. O.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: HEALTH AND TECHNOLOGY
ISSN (Print): 2190-7188
Ratings: 
  • Scopus rating (2019): CiteScore 1.7 SJR 0.246 SNIP 0.631
Original language: English
ASJC Scopus subject areas: Biotechnology, Bioengineering, Applied Microbiology and Biotechnology, Biomedical Engineering
Keywords: HF vibration, In vitro mechanical stimulation, Live cell imaging, Mechanical impacts, Mechanobiology, Real-time imaging
Source: Scopus
Source ID: 85074696220

Research output: Contribution to journalArticleScientificpeer-review

Deposition of dry particles on a fin-and-tube heat exchanger by a coupled soft-sphere DEM and CFD

In this study, a novel computational model is utilized for investigating fouling of two commonly encountered heat exchanger fin shapes in an air-conditioning application. The computational method utilizes the discrete element method (DEM) coupled with a large-eddy simulation (LES) framework. The fin-and-tube heat exchangers (FTHE) are investigated for three different Reynolds numbers (ReDh =243, 528, 793), three different particle sizes (Dp= 5, 10, 20 µm) and two different adhesive particle types based on the experimental values in the literature. The code is first benchmarked from the CFD and DEM viewpoints. A comprehensive fouling study of the FTHE's, consisting of altogether 36 simulations, is then carried out. The major numerical findings of the paper consist of the following four features. First, with low adhesive particles, the plain fin shape has a 3.45 higher volume fouling rate with ReDh =793 than at ReDh =264. With the herringbone fin shape, and the low adhesive particles, the volume fouling rate is 1.76 higher with ReDh =793 than at ReDh =264. Second, for the high adhesive particles, the plain fin has a 5.4 times higher volume fouling rate at ReDh =793 than for ReDh =264. The herringbone fin shape has a 3.92 times higher volume fouling rate with the highest Reynolds number of ReDh =793 compared to ReDh =264. Third, high adhesive particles have 3.0 times higher volume fouling rate than low adhesive particles for both fin shapes, all particle sizes and all Reynolds numbers combined. And finally, herringbone fins have 1.74 times higher volume fouling rate than plain fins for low adhesive particles. For high adhesive particles, herringbone has 1.8 times higher volume fouling rate and when both particle types are summed together, herringbone has a 1.78 times higher volume fouling rate than the plain fin shape. As a major finding of the study, the high adhesive particle collection efficiency increases monotonously with the Stokes and Reynolds numbers while low adhesive particle collection efficiency poses a non-monotonous trend.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Research group: The Instrumentation, Emissions, and Atmospheric Aerosols Group, Research area: Aerosol Physics, Aalborg University, Aalto University
Contributors: Välikangas, T., Hærvig, J., Kuuluvainen, H., Dal Maso, M., Peltonen, P., Vuorinen, V.
Number of pages: 19
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: International Journal of Heat and Mass Transfer
Article number: 119046
ISSN (Print): 0017-9310
Ratings: 
  • Scopus rating (2019): CiteScore 8.2 SJR 1.647 SNIP 1.962
Original language: English
ASJC Scopus subject areas: Condensed Matter Physics, Mechanical Engineering, Fluid Flow and Transfer Processes
Keywords: CFD-DEM, Dry-particle, Fin-and-tube heat exchanger, Fouling, Herringbone fin, Large-eddy simulation, Plain fin, Soft sphere
URLs: 
Source: Scopus
Source ID: 85075984403

Research output: Contribution to journalArticleScientificpeer-review

Synergistic Computational-Experimental Discovery of Highly Selective PtCu Nanocluster Catalysts for Acetylene Semihydrogenation

Semihydrogenation of acetylene (SHA) in an ethylene-rich stream is an important process for polymer industries. Presently, Pd-based catalysts have demonstrated good acetylene conversion (XC2H2), however, at the expense of ethylene selectivity (SC2H4). In this study, we have employed a systematic approach using density functional theory (DFT) to identify the best catalyst in a Cu-Pt system. The DFT results showed that with a 55 atom system at ∼1.1 Pt/Cu ratio for Pt28Cu27/Al2O3, the d-band center shifted -2.2 eV relative to the Fermi level leading to electron-saturated Pt, which allows only adsorption of ethylene via a π-bond, resulting in theoretical 99.7% SC2H4 at nearly complete XC2H2. Based on the DFT results, Pt-Cu/Al2O3 (PtCu) and Pt/Al2O3 (Pt) nanocatalysts were synthesized via cluster beam deposition (CBD), and their properties and activities were correlated with the computational predictions. For bimetallic PtCu, the electron microscopy results show the formation of alloys. The bimetallic PtCu catalyst closely mimics the DFT predictions in terms of both electronic structure, as confirmed by X-ray photoelectron spectroscopy, and catalytic activity. The alloying of Pt with Cu was responsible for the high C2H4 specific yield resulting from electron transfer between Cu and Pt, thus making PtCu a promising catalyst for SHA.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Research group: Materials and Molecular Modeling, INL - International Iberian Nanotechnology, University of Swansea, Edifici CM3, Iowa State University, U.S. Department of Energy, Catalan Institute for Research and Advanced Studies (ICREA)
Contributors: Ayodele, O. B., Cai, R., Wang, J., Ziouani, Y., Liang, Z., Spadaro, M. C., Kovnir, K., Arbiol, J., Akola, J., Palmer, R. E., Kolen'Ko, Y. V.
Number of pages: 7
Pages: 451-457
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: ACS CATALYSIS
ISSN (Print): 2155-5435
Ratings: 
  • Scopus rating (2019): CiteScore 19.6 SJR 4.633 SNIP 2.178
Original language: English
ASJC Scopus subject areas: Catalysis, Chemistry(all)
Keywords: alloys, cluster beam deposition, hydrogenation, microkinetic model, nanoclusters
Source: Scopus
Source ID: 85076730121

Research output: Contribution to journalArticleScientificpeer-review

Characterization of the anisotropic deformation of the right ventricle during open heart surgery

Digital Image Correlation (DIC) was used for studying the anisotropic behavior of the thin walled right ventricle of the human heart. Strains measured with Speckle Tracking Echocardiography (STE) were compared with the DIC data. Both DIC and STE were used to measure longitudinal strains of the right ventricle in the beginning of an open-heart surgery as well as after the cardiopulmonary bypass. Based on the results, the maximum end-systolic strains obtained with the DIC and STE change similarly during the surgery with less than 10% difference. The difference is largely due to the errors in matching the longitudinal direction in the two methods, sensitivity of the measurement to the positioning of the virtual extensometer of in both STE and DIC, and physiological difference of the measurements as the DIC measures the top surface of the heart whereas the STE obtains the data from below. The anisotropy of the RV was measured using full field principal strains acquired from the DIC displacement fields. The full field principal strains cover the entire region of interest instead of just two points as the virtual extensometer approach used by the STE. The principal strains are not direction dependent measures, and therefore are more independent of the anatomy of the patient and the exact positioning of the virtual strain gage or the STE probe. The results show that the longitudinal strains alone are not enough to fully characterize the behavior of the heart, as the deformation of the heart can be very anisotropic, and the anisotropy changes during the surgery, and from patient to patient.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Materials Characterization, Hospital Heart Center, Tampere University
Contributors: Soltani, A., Lahti, J., Järvelä, K., Laurikka, J., Kuokkala, V. T., Hokka, M.
Number of pages: 12
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING
ISSN (Print): 1025-5842
Ratings: 
  • Scopus rating (2019): CiteScore 2.6 SJR 0.451 SNIP 0.695
Original language: English
ASJC Scopus subject areas: Bioengineering, Biomedical Engineering, Human-Computer Interaction, Computer Science Applications
Keywords: anisotropy, biomaterial characterization, deformation, digital image correlation, heart muscle, Human biomechanics, motion

Bibliographical note

dupl=51243005

Source: Scopus
Source ID: 85076903988

Research output: Contribution to journalArticleScientificpeer-review

How well can we predict cluster fragmentation inside a mass spectrometer?

Fragmentation of molecular clusters inside mass spectrometers is a significant source of uncertainty in a wide range of chemical applications. We have measured the fragmentation of sulfuric acid clusters driving atmospheric new-particle formation, and developed a novel model, based on first principles calculations, capable of quantitatively predicting the extent of fragmentation.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: University of Helsinki, Beijing University of Chemical Technology, CNRS, Centre National de la Recherche Scientifique (CNRS), Universite de Bordeaux - PRES, Lab Bordelais Rech Informat, PICTURA Res Grp, UMR 5800
Contributors: Passananti, M., Zapadinsky, E., Zanca, T., Kangasluoma, J., Myllys, N., Rissanen, M. P., Kurtén, T., Ehn, M., Attoui, M., Vehkamäki, H.
Number of pages: 4
Pages: 5946-5949
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Chemical Communications
Volume: 55
Issue number: 42
ISSN (Print): 1359-7345
Ratings: 
  • Scopus rating (2019): CiteScore 9.8 SJR 1.992 SNIP 1.144
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
Source: Scopus
Source ID: 85065980333

Research output: Contribution to journalArticleScientificpeer-review

Less Is More: Enhancement of Second-Harmonic Generation from Metasurfaces by Reduced Nanoparticle Density

We investigate optical second-harmonic generation (SHG) from metasurfaces where noncentrosymmetric V-shaped gold nanoparticles are ordered into regular array configurations. In contrast to expectations, a substantial enhancement of the SHG signal is observed when the number density of the particles in the array is reduced. More specifically, by halving the number density, we obtain over 5-fold enhancement in SHG intensity. This striking result is attributed to favorable interparticle interactions mediated by the lattice, where surface-lattice resonances lead to spectral narrowing of the plasmon resonances. Importantly, however, the results cannot be explained by the improved quality of the plasmon resonance alone. Instead, the lattice interactions also lead to further enhancement of the local fields at the particles. The experimental observations agree very well with results obtained from numerical simulations including lattice interactions.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Photonics, Institute of Physics, Nicolaus Copernicus University, University of Eastern Finland, CRPP
Contributors: Czaplicki, R., Kiviniemi, A., Huttunen, M. J., Zang, X., Stolt, T., Vartiainen, I., Butet, J., Kuittinen, M., Martin, O. J., Kauranen, M.
Number of pages: 6
Pages: 7709-7714
Publication date: 12 Dec 2018
Peer-reviewed: Yes

Publication information

Journal: Nano Letters
Volume: 18
Issue number: 12
ISSN (Print): 1530-6984
Ratings: 
  • Scopus rating (2018): CiteScore 21.2 SJR 6.211 SNIP 2.427
Original language: English
ASJC Scopus subject areas: Bioengineering, Chemistry(all), Materials Science(all), Condensed Matter Physics, Mechanical Engineering
Keywords: interparticle interactions, Metal nanoparticles, nonlinear optics, plasmonic resonances, second-harmonic generation, surface-lattice resonances
Electronic versions: 
URLs: 
URLs: 
Source: Scopus
Source ID: 85058303843

Research output: Contribution to journalArticleScientificpeer-review

Dynamic decoupling of biomass and wax ester biosynthesis in Acinetobacter baylyi by an autonomously regulated switch

For improving the microbial production of fuels and chemicals, gene knock-outs and overexpression are routinely applied to intensify the carbon flow from substrate to product. However, their possibilities in dynamic control of the flux between the biomass and product synthesis are limited, whereas dynamic metabolic switches can be used for optimizing the distribution of carbon and resources. The production of single cell oils is especially challenging, as the synthesis is strictly regulated, competes directly with biomass, and requires defined conditions, such as nitrogen limitation. Here, we engineered a metabolic switch for redirecting carbon flow from biomass to wax ester production in Acinetobacter baylyi ADP1 using acetate as a carbon source. Isocitrate lyase, an essential enzyme for growth on acetate, was expressed under an arabinose inducible promoter. The autonomous downregulation of the expression is based on the gradual oxidation of the arabinose inducer by a glucose dehydrogenase gcd. The depletion of the inducer, occurring simultaneously to acetate consumption, switches the cells from a biomass mode to a lipid synthesis mode, enabling the efficient channelling of carbon to wax esters in a simple batch culture. In the engineered strain, the yield and titer of wax esters were improved by 3.8 and 3.1 folds, respectively, over the control strain. In addition, the engineered strain accumulated wax esters 19% of cell dry weight, being the highest reported among microbes. The study provides important insights into the dynamic engineering of the biomass-dependent synthesis pathways for the improved production of biocompounds from low-cost and sustainable substrates.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy
Contributors: Santala, S., Efimova, E., Santala, V.
Publication date: 1 Dec 2018
Peer-reviewed: Yes

Publication information

Journal: Metabolic Engineering Communications
Volume: 7
Article number: e00078
ISSN (Print): 2214-0301
Ratings: 
  • Scopus rating (2018): CiteScore 7.4 SJR 1.699 SNIP 1.112
Original language: English
ASJC Scopus subject areas: Biotechnology, Bioengineering
Keywords: Acetate, Autonomous circuit, Decoupling, Dynamic control, Lipid biosynthesis, Wax esters
Electronic versions: 
Source: Scopus
Source ID: 85053844687

Research output: Contribution to journalArticleScientificpeer-review

The importance of controlled mismatch of biomechanical compliances of implantable scaffolds and native tissue for articular cartilage regeneration

Scaffolds for articular cartilage repair have to be optimally biodegradable with simultaneous promotion of hyaline cartilage formation under rather complex biomechanical and physiological conditions. It has been generally accepted that scaffold structure and composition would be the best when it mimics the structure of native cartilage. However, a reparative construct mimicking the mature native tissue in a healing tissue site presents a biological mismatch of reparative stimuli. In this work, we studied a new recombinant human type III collagen-polylactide (rhCol-PLA) scaffolds. The rhCol-PLA scaffolds were assessed for their relative performance in simulated synovial fluids of 1 and 4 mg/mL sodium hyaluronate with application of model-free analysis with Biomaterials Enhanced Simulation Test (BEST). Pure PLA scaffold was used as a control. The BEST results were compared to the results of a prior in vivo study with rhCol-PLA. Collectively the data indicated that a successful articular cartilage repair require lower stiffness of the scaffold compared to surrounding cartilage yet matching the strain compliance both in static and dynamic conditions. This ensures an optimal combination of load transfer and effective oscillatory nutrients supply to the cells. The results encourage further development of intelligent scaffold structures for optimal articular cartilage repair rather than simply trying to imitate the respective original tissue.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Faculty of Biomedical Sciences and Engineering, Aalto University, Seqvera Ltd., University of Helsinki
Contributors: Gasik, M., Zühlke, A., Haaparanta, A., Muhonen, V., Laine, K., Bilotsky, Y., Kellomäki, M., Kiviranta, I.
Publication date: 30 Nov 2018
Peer-reviewed: Yes

Publication information

Journal: Frontiers in Bioengineering and Biotechnology
Volume: 6
Issue number: NOV
Article number: 187
ISSN (Print): 2296-4185
Ratings: 
  • Scopus rating (2018): CiteScore 6.1 SJR 1.248 SNIP 1.327
Original language: English
ASJC Scopus subject areas: Biotechnology, Bioengineering, Histology, Biomedical Engineering
Keywords: Articular cartilage, Biomechanics, Collagen, PLA, Scaffold, Synovial fluid, Testing
Electronic versions: 
Source: Scopus
Source ID: 85058709882

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 1.4 SJR 0.754 SNIP 0.683
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

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 8.7 SJR 1.842 SNIP 0.98
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

Molecular-Scale Ligand Effects in Small Gold-Thiolate Nanoclusters

Because of the small size and large surface area of thiolate-protected Au nanoclusters (NCs), the protecting ligands are expected to play a substantial role in modulating the structure and properties, particularly in the solution phase. However, little is known on how thiolate ligands explicitly modulate the structural properties of the NCs at atomic level, even though this information is critical for predicting the performance of Au NCs in application settings including as a catalyst interacting with small molecules and as a sensor interacting with biomolecular systems. Here, we report a combined experimental and theoretical study, using synchrotron X-ray spectroscopy and quantum mechanics/molecular mechanics simulations, that investigates how the protecting ligands impact the structure and properties of small Au18(SR)14 NCs. Two representative ligand types, smaller aliphatic cyclohexanethiolate and larger hydrophilic glutathione, are selected, and their structures are followed experimentally in both solid and solution phases. It was found that cyclohexanethiolate ligands are significantly perturbed by toluene solvent molecules, resulting in structural changes that cause disorder on the surface of Au18(SR)14 NCs. In particular, large surface cavities in the ligand shell are created by interactions between toluene and cyclohexanethiolate. The appearance of these small molecule-accessible sites on the NC surface demonstrates the ability of Au NCs to act as a catalyst for organic phase reactions. In contrast, glutathione ligands encapsulate the Au NC core via intermolecular interactions, minimizing structural changes caused by interactions with water molecules. The much better protection from glutathione ligands imparts a rigidified surface and ligand structure, making the NCs desirable for biomedical applications due to the high stability and also offering a structural-based explanation for the enhanced photoluminescence often reported for glutathione-protected Au NCs.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Dalhousie University, Universitat Autonoma de Barcelona, Spain, Catalan Institute for Research and Advanced Studies (ICREA), Carnegie Mellon University, National University of Singapore, Norwegian Univ. of Sci. and Technol.
Contributors: Chevrier, D. M., Raich, L., Rovira, C., Das, A., Luo, Z., Yao, Q., Chatt, A., Xie, J., Jin, R., Akola, J., Zhang, P.
Number of pages: 7
Pages: 15430-15436
Publication date: 14 Nov 2018
Peer-reviewed: Yes

Publication information

Journal: Journal of the American Chemical Society
Volume: 140
Issue number: 45
ISSN (Print): 0002-7863
Ratings: 
  • Scopus rating (2018): CiteScore 24.4 SJR 7.468 SNIP 2.652
Original language: English
ASJC Scopus subject areas: Catalysis, Chemistry(all), Biochemistry, Colloid and Surface Chemistry
Source: Scopus
Source ID: 85056236370

Research output: Contribution to journalArticleScientificpeer-review

Chromatographic studies of n-Propyl Propionate: Adsorption equilibrium, modelling and uncertainties determination

The n-Propyl Propionate (ProPro) is a compound that has several possible industrial applications. However, the current production route of this component presents several problems, such as the downstream purification. In this way, chromatographic separation could be an alternative solution to the downstream purification. In this work experimental studies of the ProPro reaction system separation in a chromatographic fixed bed unit packed with Amberlyst 46 were performed. The adsorption equilibrium isotherms and the corresponding Langmuir model parameters were determined. A phenomenological model to represent the process was developed and validated through the experimental data. Meanwhile, it is proposed the characterization of the uncertainties of all steps and its extension to the model prediction, which allowed to estimate the model parameters with a reduced number of experiments, when compared with other reports in the literature; nevertheless, the final results lead to a statistically more reliable model.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Automation and Hydraulic Engineering, Research group: Automation and Systems Theory, Universidade do Porto, Federal Univ. of Bahia
Contributors: Nogueira, I. B., Faria, R. P., Requião, R., Koivisto, H., Martins, M. A., Rodrigues, A. E., Loureiro, J. M., Ribeiro, A. M.
Number of pages: 12
Pages: 371-382
Publication date: 2 Nov 2018
Peer-reviewed: Yes

Publication information

Journal: Computers and Chemical Engineering
Volume: 119
ISSN (Print): 0098-1354
Ratings: 
  • Scopus rating (2018): CiteScore 6.1 SJR 0.932 SNIP 1.562
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Computer Science Applications
Keywords: Adsorption equilibrium isotherms, Confidence region, Fixed bed adsorptive unit, n-Propyl Propionate, Particle swarm optimization
Source: Scopus
Source ID: 85054180293

Research output: Contribution to journalArticleScientificpeer-review

Tribocorrosion behaviour of aluminium bronze in 3.5 wt.% NaCl solution

Tribocorrosion behaviour of aluminium bronze CuAl10Fe5Ni5 in 3.5 wt.% NaCl solution was investigated in a pin-on-disc facility containing an electrochemical cell. Oxidising capacity and contact pressure to alumina counterbody were varied. Pure corrosion occurred as selective dissolution of α phase included in the eutectoid structure. Contact to counterbody introduced plastic deformation, extrusion of the material and abrasive wear. Wear-corrosion interactions varied between the two contact pressures, with lower material losses appearing at the higher pressure. The significant acceleration of material degradation by the interactions was not clearly reflected to kinetics or thermodynamics of corrosion. These results are presented and discussed here.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Photonics, VTT Technical Research Centre of Finland
Contributors: Huttunen-Saarivirta, E., Isotahdon, E., Metsäjoki, J., Salminen, T., Carpén, L., Ronkainen, H.
Number of pages: 17
Pages: 207-223
Publication date: 1 Nov 2018
Peer-reviewed: Yes

Publication information

Journal: Corrosion Science
Volume: 144
ISSN (Print): 0010-938X
Ratings: 
  • Scopus rating (2018): CiteScore 10.3 SJR 2.131 SNIP 2.759
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all), Materials Science(all)
Keywords: Corrosion, Plastic deformation, Selective dissolution, Tribocorrosion, Wear

Bibliographical note

EXT="Huttunen-Saarivirta, E."
EXT="Isotahdon, E."
EXT="Metsäjoki, J."

Source: Scopus
Source ID: 85053038794

Research output: Contribution to journalArticleScientificpeer-review

Novel osteoconductive β-tricalcium phosphate/poly(L-lactide-co-e-caprolactone) scaffold for bone regeneration: a study in a rabbit calvarial defect

The advantages of synthetic bone graft substitutes over autogenous bone grafts include abundant graft volume, lack of complications related to the graft harvesting, and shorter operation and recovery times for the patient. We studied a new synthetic supercritical CO2 –processed porous composite scaffold of β-tricalcium phosphate and poly(L-lactide-co-caprolactone) copolymer as a bone graft substitute in a rabbit calvarial defect. Bilateral 12 mm diameter critical size calvarial defects were successfully created in 18 rabbits. The right defect was filled with a scaffold moistened with bone marrow aspirate, and the other was an empty control. The material was assessed for applicability during surgery. The follow-up times were 4, 12, and 24 weeks. Radiographic and micro-CT studies and histopathological analysis were used to evaluate new bone formation, tissue ingrowth, and biocompatibility. The scaffold was easy to shape and handle during the surgery, and the bone-scaffold contact was tight when visually evaluated after the implantation. The material showed good biocompatibility and its porosity enabled rapid invasion of vasculature and full thickness mesenchymal tissue ingrowth already at four weeks. By 24 weeks, full thickness bone ingrowth within the scaffold and along the dura was generally seen. In contrast, the empty defect had only a thin layer of new bone at 24 weeks. The radiodensity of the material was similar to the density of the intact bone. In conclusion, the new porous scaffold material, composed of microgranular β-TCP bound into the polymer matrix, proved to be a promising osteoconductive bone graft substitute with excellent handling properties. [Figure not available: see fulltext.].

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electronics and Communications Engineering, Faculty of Biomedical Sciences and Engineering, Research group: Computational Biophysics and Imaging Group, Faculty of Veterinary Medicine, University of Helsinki, Orton Orthopaedic Hospital, Muonio Health Center
Contributors: Pihlman, H., Keränen, P., Paakinaho, K., Linden, J., Hannula, M., Manninen, I. K., Hyttinen, J., Manninen, M., Laitinen-Vapaavuori, O.
Publication date: 1 Oct 2018
Peer-reviewed: Yes

Publication information

Journal: Journal of Materials Science: Materials in Medicine
Volume: 29
Issue number: 10
Article number: 156
ISSN (Print): 0957-4530
Ratings: 
  • Scopus rating (2018): CiteScore 4.7 SJR 0.612 SNIP 0.855
Original language: English
ASJC Scopus subject areas: Biophysics, Bioengineering, Biomaterials, Biomedical Engineering
Source: Scopus
Source ID: 85054473480

Research output: Contribution to journalArticleScientificpeer-review

Molecular Communications Pulse-based Jamming Model for Bacterial Biofilm Suppression

Studies have recently shown that the bacteria survivability within biofilms is responsible for the emergence of superbugs. The combat of bacterial infections, without enhancing its resistance to antibiotics, includes the use of nanoparticles to quench the quorum sensing of these biofilm-forming bacteria. Several sequential and parallel multi-stage communication processes are involved in the formation of biofilms. In this paper, we use proteomic data from a wet lab experiment to identify the communication channels that are vital to these processes.We also identified the main proteins from each channel and propose the use of jamming signals from synthetically engineered bacteria to suppress the production of those proteins. This biocompatible technique is based on synthetic biology and enables the inhibition of biofilm formation. We analyse the communications performance of the jamming process, by evaluating the path loss for a number of conditions that include different engineered bacterial population sizes, distances between the populations and molecular signal power. Our results show that sufficient molecular pulsebased jamming signals are able to prevent the biofilm formation by creating lossy communications channels (almost -3 dB for certain scenarios). From these results, we define the main design parameters to develop a fully operational bacteria-based jamming system.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electronics and Communications Engineering, Research group: Emerging Technologies for Nano-Bio-Info-Cogno, Waterford Institute of Technology, Kasetsart University
Contributors: Martins, D. P., Leetanasaksakul, K., Barros, M. T., Thamchaipenet, A., Donnelly, W., Balasubramaniam, S.
Number of pages: 12
Pages: 533-542
Publication date: Oct 2018
Peer-reviewed: Yes
Early online date: 19 Sep 2018

Publication information

Journal: IEEE Transactions on Nanobioscience
Volume: 17
Issue number: 4
ISSN (Print): 1536-1241
Ratings: 
  • Scopus rating (2018): CiteScore 5 SJR 0.541 SNIP 0.792
Original language: English
ASJC Scopus subject areas: Biotechnology, Bioengineering, Medicine (miscellaneous), Biomedical Engineering, Pharmaceutical Science, Computer Science Applications, Electrical and Electronic Engineering
Keywords: Biofilm suppression, Communications systems, Jamming, Synthetic logic circuits
Source: Scopus
Source ID: 85053611196

Research output: Contribution to journalArticleScientificpeer-review

Temperature control as key factor for optimal biohydrogen production from thermomechanical pulping wastewater

This study evaluates the use of non-pretreated thermo-mechanical pulping (TMP) wastewater as a potential substrate for hydrogen production by dark fermentation. Batch incubations were conducted in a temperature gradient incubator at temperatures ranging from 37 to 80 °C, using an inoculum from a thermophilic, xylose-fed, hydrogen-producing fluidised bed reactor. The aim was to assess the short-term response of the microbial communities to the different temperatures with respect to both hydrogen yield and composition of the active microbial community. High throughput sequencing (MiSeq) of the reversely transcribed 16S rRNA showed that Thermoanaerobacterium sp. dominated the active microbial community at 70 °C, resulting in the highest hydrogen yield of 3.6 (±0.1) mmol H2 g−1 CODtot supplied. Lower hydrogen yields were obtained at the temperature range from 37 to 65 °C, likely due to consumption of the produced hydrogen by homoacetogenesis. No hydrogen production was detected at temperatures above 70 °C. Thermomechanical pulping wastewaters are released at high temperatures (50–80 °C), and thus dark fermentation at 70 °C could be sustained using the heat produced by the pulp and paper plant itself without any requirement for external heating.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, Research group: Industrial Bioengineering and Applied Organic Chemistry, Natl. University of Ireland, Galway, Institute for Water Education, UNESCO–IHE
Contributors: Dessì, P., Porca, E., Lakaniemi, A., Collins, G., Lens, P. N.
Number of pages: 8
Pages: 214-221
Publication date: 15 Sep 2018
Peer-reviewed: Yes

Publication information

Journal: Biochemical Engineering Journal
Volume: 137
ISSN (Print): 1369-703X
Ratings: 
  • Scopus rating (2018): CiteScore 6 SJR 0.904 SNIP 1.167
Original language: English
ASJC Scopus subject areas: Biotechnology, Bioengineering, Environmental Engineering, Biomedical Engineering
Keywords: Dark fermentation, MiSeq, Pulp and paper mill wastewater, Thermoanaerobacterium, Thermomechanical pulping, Thermophilic
Source: Scopus
Source ID: 85048157059

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 7.3 SJR 1.158 SNIP 1.469
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

Performance of a biotrickling filter for the anaerobic utilization of gas-phase methanol coupled to thiosulphate reduction and resource recovery through volatile fatty acids production

The anaerobic removal of continuously fed gas-phase methanol (2.5–30 g/m3.h) and the reduction of step-fed thiosulphate (1000 mg/L) was investigated in a biotrickling filter (BTF) operated for 123 d at an empty bed residence time (EBRT) of 4.6 and 2.3 min. The BTF performance during steady step-feed and special operational phases like intermittent liquid trickling in 6 and 24 h cycles and operation without pH regulation were evaluated. Performance of the BTF was not affected and nearly 100% removal of gas-phase methanol was achieved with an ECmax of 21 g/m3.h. Besides, >99% thiosulphate reduction was achieved, in all the phases of operation. The production of sulphate, H2S and volatile fatty acids (VFA) was monitored and a maximum of 2500 mg/L of acetate, 200 mg/L of propionate, 150 mg/L of isovalerate and 100 mg/L isobutyrate was produced.

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, Institute for Water Education
Contributors: Eregowda, T., Matanhike, L., Rene, E. R., Lens, P. N.
Number of pages: 10
Pages: 591-600
Publication date: 1 Sep 2018
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 263
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2018): CiteScore 11.1 SJR 2.157 SNIP 1.858
Original language: English
ASJC Scopus subject areas: Bioengineering, Environmental Engineering, Renewable Energy, Sustainability and the Environment, Waste Management and Disposal
Keywords: Anaerobic, Biotrickling filter (BTF), Gas-phase methanol, Steady and intermittent BTF operation, Thiosulphate reduction, Volatile fatty acid
Source: Scopus
Source ID: 85047081553

Research output: Contribution to journalArticleScientificpeer-review

Effects of pyrolysis temperature on the hydrologically relevant porosity of willow biochar

Biochar pore space consists of porosity of multiple length scales. In direct water holding applications like water storage for plant water uptake, the main interest is in micrometre-range porosity since these pores are able to store water that is easily available for plants. Gas adsorption measurements which are commonly used to characterize the physical pore structure of biochars are not able to quantify this pore-size range. While pyrogenetic porosity (i.e. pores formed during pyrolysis process) tends to increase with elevated process temperature, it is uncertain whether this change affects the pore space capable to store plant available water. In this study, we characterized biochar porosity with x-ray tomography which provides quantitative information on the micrometer-range porosity. We imaged willow dried at 60 °C and biochar samples pyrolysed in three different temperatures (peak temperatures 308, 384, 489 °C, heating rate 2 °C min−1). Samples were carefully prepared and traced through the experiments, which allowed investigation of porosity development in micrometre size range. Pore space was quantified with image analysis of x-ray tomography images and, in addition, nanoscale porosity was examined with helium ion microscopy. The image analysis results show that initial pore structure of the raw material determines the properties of micrometre-range porosity in the studied temperature range. Thus, considering the pore-size regime relevant to the storage of plant available water, pyrolysis temperature in the studied range does not provide means to optimize the biochar structure. However, these findings do not rule out that process temperature may affect the water retention properties of biochars by modifying the chemical properties of the pore surfaces.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Faculty of Biomedical Sciences and Engineering, Natural Resources Institute Finland (Luke), Jyväskylän yliopisto, Foshan University, Zhejiang A & F University
Contributors: Hyväluoma, J., Hannula, M., Arstila, K., Wang, H., Kulju, S., Rasa, K.
Publication date: Sep 2018
Peer-reviewed: Yes
Early online date: 2018

Publication information

Journal: Journal of Analytical and Applied Pyrolysis
Volume: 134
ISSN (Print): 0165-2370
Ratings: 
  • Scopus rating (2018): CiteScore 6.2 SJR 1.11 SNIP 1.256
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all)
Keywords: Biochar, Image analysis, Porosity, Slow pyrolysis, X-ray tomography

Bibliographical note

EXT="Kulju, Sampo"

Source: Scopus
Source ID: 85050304071

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 1.4 SJR 0.754 SNIP 0.683
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

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 2.2 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 4.8 SJR 0.715 SNIP 0.891
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

High Bending-Mode Sensitivity of Printed Piezoelectric Poly(vinylidenefluoride- co-trifluoroethylene) Sensors

Printable piezoelectric sensors were fabricated on a flexible polyethylene terephthalate (PET) substrate. Solution-processed piezoelectric poly(vinylidenefluoride-co-trifluoroethylene) ink was used as an active layer. Evaporated silver on PET was used as the bottom electrode and the painted silver glue as the top electrode. The sensors were poled using a high dc electric field from 25 to 65 MV m-1, yielding piezoelectric normal direction sensitivities up to 25 pC N-1. Bending-mode sensitivities showed values up to 200 nC N-1, which is 4 orders of magnitude larger than the force sensitivity in the normal direction. The high bending-mode sensitivities suggest suitability for detecting small forces, such as single fiber bonds or cardiomyocyte cell-beating force.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Faculty of Biomedical Sciences and Engineering, Nokia Technologies, University of Twente
Contributors: Rajala, S., Schouten, M., Krijnen, G., Tuukkanen, S.
Number of pages: 7
Pages: 8067-8073
Publication date: 23 Jul 2018
Peer-reviewed: Yes

Publication information

Journal: ACS Omega
Volume: 3
Issue number: 7
ISSN (Print): 2470-1343
Ratings: 
  • Scopus rating (2018): CiteScore 1.4 SJR 0.754 SNIP 0.683
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all)
Electronic versions: 

Bibliographical note

EXT="Rajala, Satu"

Source: Scopus
Source ID: 85050457848

Research output: Contribution to journalArticleScientificpeer-review

Fluid flow simulations meet high-speed video: Computer vision comparison of droplet dynamics

Hypothesis: While multiphase flows, particularly droplet dynamics, are ordinary in nature as well as in industrial processes, their mathematical and computational modelling continue to pose challenging research tasks - patent approaches for tackling them are yet to be found. The lack of analytical flow field solutions for non-trivial droplet dynamics hinders validation of computer simulations and, hence, their application in research problems. High-speed videos and computer vision algorithms can provide a viable approach to validate simulations directly against experiments. Experiments: Droplets of water (or glycerol-water mixtures) impacting on both hydrophobic and superhydrophobic surfaces were imaged with a high-speed camera. The corresponding configurations were simulated using a lattice-Boltzmann multiphase scheme. Video frames from experiments and simulations were compared, by means of computer vision, over entire droplet impact events. Findings: The proposed experimental validation procedure provides a detailed, dynamic one-on-one comparison of a droplet impact. The procedure relies on high-speed video recording of the experiments, computer vision, and on a software package for the analyzation routines. The procedure is able to quantitatively validate computer simulations against experiments and it is widely applicable to multiphase flow systems in general.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Natural Resources Institute Finland (Luke), BioFluidix GmbH, Faculty of Information Technology, Jyväskylän yliopisto
Contributors: Kulju, S., Riegger, L., Koltay, P., Mattila, K., Hyväluoma, J.
Number of pages: 9
Pages: 48-56
Publication date: 15 Jul 2018
Peer-reviewed: Yes

Publication information

Journal: Journal of Colloid and Interface Science
Volume: 522
ISSN (Print): 0021-9797
Ratings: 
  • Scopus rating (2018): CiteScore 9 SJR 1.29 SNIP 1.342
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Biomaterials, Surfaces, Coatings and Films, Colloid and Surface Chemistry
Keywords: Computer vision, Droplet, Experimental, High-speed video, Hydrophobic, Lattice Boltzmann, Simulation

Bibliographical note

EXT="Kulju, S."

Source: Scopus
Source ID: 85044153494

Research output: Contribution to journalArticleScientificpeer-review

Effect of surfactant type and sonication energy on the electrical conductivity properties of nanocellulose-CNT nanocomposite films

We present a detailed study on the influence of sonication energy and surfactant type on the electrical conductivity of nanocellulose-carbon nanotube (NFC-CNT) nanocomposite films. The study was made using a minimum amount of processing steps, chemicals and materials, to optimize the conductivity properties of free-standing flexible nanocomposite films. In general, the NFC-CNT film preparation process is sensitive concerning the dispersing phase of CNTs into a solution with NFC. In our study, we used sonication to carry out the dispersing phase of processing in the presence of surfactant. In the final phase, the films were prepared from the dispersion using centrifugal cast molding. The solid films were analyzed regarding their electrical conductivity using a four-probe measuring technique. We also characterized how conductivity properties were enhanced when surfactant was removed from nanocomposite films; to our knowledge this has not been reported previously. The results of our study indicated that the optimization of the surfactant type clearly affected the formation of freestanding films. The effect of sonication energy was significant in terms of conductivity. Using a relatively low 16 wt. % concentration of multiwall carbon nanotubes we achieved the highest conductivity value of 8.4 S/cm for nanocellulose-CNT films ever published in the current literature. This was achieved by optimizing the surfactant type and sonication energy per dry mass. Additionally, to further increase the conductivity, we defined a preparation step to remove the used surfactant from the final nanocomposite structure.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science, Faculty of Biomedical Sciences and Engineering, VTT Technical Research Centre of Finland
Contributors: Siljander, S., Keinänen, P., Räty, A., Ramakrishnan, K. R., Tuukkanen, S., Kunnari, V., Harlin, A., Vuorinen, J., Kanerva, M.
Publication date: 20 Jun 2018
Peer-reviewed: Yes

Publication information

Journal: International Journal of Molecular Sciences
Volume: 19
Issue number: 6
Article number: 1819
ISSN (Print): 1661-6596
Ratings: 
  • Scopus rating (2018): CiteScore 5.2 SJR 1.312 SNIP 1.274
Original language: English
ASJC Scopus subject areas: Catalysis, Molecular Biology, Spectroscopy, Computer Science Applications, Physical and Theoretical Chemistry, Organic Chemistry, Inorganic Chemistry
Keywords: Carbon nanotubes, Conductivity, Nanocellulose, Nanocomposite, Surfactant
Electronic versions: 

Bibliographical note

INT=mol,"Räty, Anna"
EXT="Harlin, Ali"

Source: Scopus
Source ID: 85048936349

Research output: Contribution to journalArticleScientificpeer-review

The effect of carbon and nickel additions on the precursor synthesis of Cr3C2-Ni nanopowder

Decreasing crystal size to nanoscale is a proven method to enhance material properties. In this study, nanosize Cr3C2 and Cr3C2-Ni were synthetized and the reaction sequence was studied. Aqueous precursors using only water-soluble raw materials with varying carbon contents and a nickel addition were spray-dried. Glycine was used as a carbon source and chromium acetate hydroxide as a chromium source in the precursor solutions. Nickel nitrate hexahydrate was introduced as a nickel source to yield a metallic binder into the carbide nanopowder.Resulting powders were heat-treating to identify an applicable precursor composition producing the targeted Cr3C2 phase with crystal size of tens of nanometers. Thermal synthesis tests of the precursor powders to yield Cr3C2 took place at a temperature between 900 and 1300 °C under an Argon atmosphere. The synthesis of nanosize Cr3C2-Ni powder was successful at 1000 °C in 30 min, in a case of the best precursor. In order to produce the carbide phase with no residual oxide traces, relative carbon load has to be 48 wt%, while the stoichiometric amount of carbon in Cr3C2 is 13 wt%. When also introducing the nickel source into the precursor, an even higher carbon load was required. The carbon surplus needed to enable the Cr3C2 synthesis attributes to the non-homogeneity of the precursor composition.The chemical synthesis starting from water-soluble raw materials is a promising way of preparing nanosize Cr3C2-Ni with the targeted phase configuration.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science, Research group: Materials Characterization, VTT Technical Research Centre of Finland
Contributors: Kaunisto, K., Kotilainen, M., Karhu, M., Lagerbom, J., Vuorinen, T., Honkanen, M., Vippola, M., Turunen, E.
Pages: 9338-9346
Publication date: 1 Jun 2018
Peer-reviewed: Yes
Early online date: 2018

Publication information

Journal: Ceramics International
Volume: 44
Issue number: 8
ISSN (Print): 0272-8842
Ratings: 
  • Scopus rating (2018): CiteScore 5.2 SJR 0.888 SNIP 1.297
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Ceramics and Composites, Process Chemistry and Technology, Surfaces, Coatings and Films, Materials Chemistry
Keywords: A. Nanosize CrC synthesis, A. Powders: chemical preparation, B. Grain size, D. Carbides, E. Wear parts

Bibliographical note

EXT="Vuorinen, Tommi"
EXT="Lagerbom, Juha"
EXT="Kaunisto, Kimmo"

Source: Scopus
Source ID: 85042300396

Research output: Contribution to journalArticleScientificpeer-review

The effects of laser patterning 10CeTZP-Al2O3 nanocomposite disc surfaces: Osseous differentiation and cellular arrangement in vitro

Customized square grid arrangements of different groove depths (1.0, 1.5 and 3.0 μm) and separations (10 and 30 μm) were successfully laser patterned, using a nanosecond pulsed fibre laser, on the surface of 10 mol% ceria-stabilized zirconia and alumina (10CeTZP-Al2O3) nanocomposite discs (diameter: 10 mm; thickness: 1.5 mm). The patterned surfaces and the in vitro biological response of osteoblasts (SAOS-2) towards them were thoroughly analysed. In terms of composition, the laser treatment was found to cause superficial monoclinic-tetragonal zirconia phase transformation and alumina evaporation. In vitro, the most effective grid configuration for osseous differentiation was found to be 1.5 μm groove depth and 10 μm groove separation, and confocal microscopy revealed that the cells show a tendency to be sorted as groove depth increases. It is thought that custom-made patterns could be produced to guide cell attachment in vivo, which could favour implant integration and reduce healing time.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science, Mechanical Engineering and Industrial Systems, Nanoker Research, Universidad de Oviedo
Contributors: Goyos-Ball, L., Prado, C., Díaz, R., Fernández, E., Ismailov, A., Kumpulainen, T., Levänen, E., Torrecillas, R., Fernández, A.
Pages: 9472-9478
Publication date: Jun 2018
Peer-reviewed: Yes
Early online date: 2018

Publication information

Journal: Ceramics International
Volume: 44
Issue number: 8
ISSN (Print): 0272-8842
Ratings: 
  • Scopus rating (2018): CiteScore 5.2 SJR 0.888 SNIP 1.297
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Ceramics and Composites, Process Chemistry and Technology, Surfaces, Coatings and Films, Materials Chemistry
Keywords: Alumina, Cellular arrangement, Ceramic nanocomposite, Laser patterning, Osseous differentiation, Zirconia
Source: Scopus
Source ID: 85042621677

Research output: Contribution to journalArticleScientificpeer-review

Influence of the phosphate glass melt on the corrosion of functional particles occurring during the preparation of glass-ceramics

We report our findings on the impact of the glass composition on the corrosion of microparticles occurring during the preparation of glass-ceramics using the direct doping method. Microparticles (MPs) with the composition Sr4Al14O25:Eu2+,Dy3+ with blue-green persistent luminescence were chosen as the changes in their spectroscopic properties can be related to the MPs’ corrosion. The MPs were added in phosphate-based glasses with different compositions. When using the same doping parameters, the glass system with the composition 90NaPO3-10Na2O (mol%) was found to be the least corrosive on the MPs whereas the glass system with the composition 90NaPO3-10NaF (mol%) is the most corrosive on the MPs probably due to their different viscosity at 575 °C, the temperature at which the MPs are added in the glass melts.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Photonics, Research group: Nanophotonics, Turun Yliopisto/Turun Biomateriaalikeskus, Laboratory of Photonics
Contributors: Ojha, N., Laihinen, T., Salminen, T., Lastusaari, M., Petit, L.
Pages: 11807-11811
Publication date: Jun 2018
Peer-reviewed: Yes
Early online date: 1 Jan 2018

Publication information

Journal: Ceramics International
Volume: 44
Issue number: 10
ISSN (Print): 0272-8842
Ratings: 
  • Scopus rating (2018): CiteScore 5.2 SJR 0.888 SNIP 1.297
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Ceramics and Composites, Process Chemistry and Technology, Surfaces, Coatings and Films, Materials Chemistry
Keywords: Corrosion, Direct doping method, Glass melt, Phosphate glass-ceramics, SrAlO:Eu, Dy microparticles
Source: Scopus
Source ID: 85044921933

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 1.4 SJR 0.754 SNIP 0.683
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all)
Source: Scopus
Source ID: 85046661219

Research output: Contribution to journalArticleScientificpeer-review

A Ceramide-Regulated Element in the Late Endosomal Protein LAPTM4B Controls Amino Acid Transporter Interaction

Membrane proteins are functionally regulated by the composition of the surrounding lipid bilayer. The late endosomal compartment is a central site for the generation of ceramide, a bioactive sphingolipid, which regulates responses to cell stress. The molecular interactions between ceramide and late endosomal transmembrane proteins are unknown. Here, we uncover in atomistic detail the ceramide interaction of Lysosome Associated Protein Transmembrane 4B (LAPTM4B), implicated in ceramide-dependent cell death and autophagy, and its functional relevance in lysosomal nutrient signaling. The ceramide-mediated regulation of LAPTM4B depends on a sphingolipid interaction motif and an adjacent aspartate residue in the protein's third transmembrane (TM3) helix. The interaction motif provides the preferred contact points for ceramide while the neighboring membrane-embedded acidic residue confers flexibility that is subject to ceramide-induced conformational changes, reducing TM3 bending. This facilitates the interaction between LAPTM4B and the amino acid transporter heavy chain 4F2hc, thereby controlling mTORC signaling. These findings provide mechanistic insights into how transmembrane proteins sense and respond to ceramide.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, University of Helsinki Faculty of Medicine, Minerva Foundation Institute for Medical Research Helsinki, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Laboratory of Physics, Abo Akademi University, Queens College, City University of New York, University of Helsinki
Contributors: Zhou, K., Dichlberger, A., Martinez-Seara, H., Nyholm, T. K., Li, S., Kim, Y. A., Vattulainen, I., Ikonen, E., Blom, T.
Number of pages: 11
Pages: 548-558
Publication date: 23 May 2018
Peer-reviewed: Yes

Publication information

Journal: ACS Central Science
Volume: 4
Issue number: 5
ISSN (Print): 2374-7943
Ratings: 
  • Scopus rating (2018): CiteScore 12.2 SJR 4.94 SNIP 2.058
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all)
Source: Scopus
Source ID: 85047534763

Research output: Contribution to journalArticleScientificpeer-review

Wet etching of dilute nitride GaInNAs, GaInNAsSb, and GaNAsSb alloys lattice-matched to GaAs

We have studied the etching of GaInNAs, GaInNAsSb, and GaNAsSb alloys by NH4OH, H2SO4, and H3PO4 based solutions. NH4OH based solutions resulted in smooth surface, while other solutions created rougher and granular surfaces. The etch rates were found to increase with the Sb content. For GaInNAs, x-ray photoelectron spectroscopy revealed the enrichment of In on the etched surfaces, indicating In or In oxides having a smaller removal rate compared to Ga or Ga oxides. The enrichment of In was associated with smoother surfaces after etching and an enhanced photoluminescence caused by lower surface recombination due to reduced surface state density.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Photonics, Research group: ORC, Department of Physics and Astronomy, University of Turku, Turun Yliopisto/Turun Biomateriaalikeskus
Contributors: Raappana, M., Polojärvi, V., Aho, A., Mäkelä, J., Aho, T., Tukiainen, A., Laukkanen, P., Guina, M.
Number of pages: 7
Pages: 268-274
Publication date: 15 May 2018
Peer-reviewed: Yes

Publication information

Journal: Corrosion Science
Volume: 136
ISSN (Print): 0010-938X
Ratings: 
  • Scopus rating (2018): CiteScore 10.3 SJR 2.131 SNIP 2.759
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all), Materials Science(all)
Keywords: A. Alloy, B. AFM, B. XPS, C. Acid corrosion, C. Alkaline corrosion, C. Passivity
Electronic versions: 
URLs: 

Bibliographical note

EXT="Mäkelä, Jaakko"
EXT="Laukkanen, Pekka"

Source: Scopus
Source ID: 85044276587

Research output: Contribution to journalArticleScientificpeer-review

Switchable light reflectance in dilute magneto-optical colloids based on nickel ferrite nanowires

Optical properties of diluted narrow band gap magnetic semiconductor nanowire colloids are controlled by modest magnetic fields under 100 Oe. High aspect ratio NiFe2O4 nanowires are used to achieve responsiveness to magnetic field, light absorption and -scattering. Visible light reflectance of the diluted colloids can be either increased or decreased depending on the nanowire alignment relative to the direction of the light propagation. The prepared colloids can be applied as magneto-optical switches or as smart window devices.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Photonics, Institute of Physics, University of Tartu, Riga Technical University, CRPP, University of Latvia
Contributors: Sutka, A., Timusk, M., Joost, U., Ignatans, R., Maiorov, M.
Number of pages: 3
Pages: 119-121
Publication date: 2 May 2018
Peer-reviewed: Yes

Publication information

Journal: e-Journal of Surface Science and Nanotechnology
Volume: 16
ISSN (Print): 1348-0391
Ratings: 
  • Scopus rating (2018): CiteScore 0.9 SJR 0.216 SNIP 0.317
Original language: English
ASJC Scopus subject areas: Biotechnology, Bioengineering, Condensed Matter Physics, Mechanics of Materials, Surfaces and Interfaces, Surfaces, Coatings and Films
Keywords: Colloid, Ferrimagnetic, Magneto-optical, Nanowire, NiFe2O4

Bibliographical note

INT=fot,"Joost, Urmas"

Source: Scopus
Source ID: 85047369076

Research output: Contribution to journalArticleScientificpeer-review

Characteristics of nFOG, an aerosol-based wet thin film coating technique

An atmospheric pressure aerosol-based wet thin film coating technique called the nFOG is characterized and applied in polymer film coatings. In the nFOG, a fog of droplets is formed by two air-assist atomizers oriented toward each other inside a deposition chamber. The droplets settle gravitationally and deposit on a substrate, forming a wet film. In this study, the continuous deposition mode of the nFOG is explored. We determined the size distribution of water droplets inside the chamber in a wide side range of 0.1–100 µm and on the substrate using aerosol measurement instruments and optical microscopy, respectively. The droplet size distribution was found to be bimodal with droplets of approximately 30–50 µm contributing the most to the mass of the formed wet film. The complementary measurement methods allow us to estimate the role of different droplet deposition mechanisms. The obtained results suggest that the deposition velocity of the droplets is lower than the calculated terminal settling velocity, likely due to the flow fields inside the chamber. Furthermore, the mass flux of the droplets onto the substrate is determined to be in the order of 1 g/m3s, corresponding to a wet film growth rate of 1 µm/s. Finally, the nFOG technique is demonstrated by preparing polymer films with thicknesses in the range of approximately 0.1–20 µm.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Materials Science, RISE Bioscience and Materials, Research Institutes of Sweden, Lund University
Contributors: Harra, J., Tuominen, M., Juuti, P., Rissler, J., Koivuluoto, H., Haapanen, J., Niemelä-Anttonen, H., Stenroos, C., Teisala, H., Lahti, J., Kuusipalo, J., Vuoristo, P., Mäkelä, J. M.
Number of pages: 10
Pages: 623-632
Publication date: May 2018
Peer-reviewed: Yes
Early online date: 1 Feb 2018

Publication information

Journal: Journal of Coatings Technology Research
Volume: 15
Issue number: 3
ISSN (Print): 1547-0091
Ratings: 
  • Scopus rating (2018): CiteScore 2.4 SNIP 0.716
Original language: English
ASJC Scopus subject areas: Chemistry(all), Surfaces and Interfaces, Surfaces, Coatings and Films, Colloid and Surface Chemistry
Keywords: Aerosol measurement, Droplet size distribution, nFOG, Polymer film, Wet coating technique

Bibliographical note

EXT="Tuominen, Mikko"

Source: Scopus
Source ID: 85045145179

Research output: Contribution to journalArticleScientificpeer-review

Membrane bound COMT isoform is an interfacial enzyme: General mechanism and new drug design paradigm

The enzyme catechol-O-methyltransferase (COMT) has water soluble (S-COMT) and membrane associated (MB-COMT), bitopic, isoforms. Of these MB-COMT is a drug target in relation to the treatment of Parkinson's disease. Using a combination of computational and experimental protocols, we have determined the substrate selection mechanism specific to MB-COMT. We show: (1) substrates with preferred affinity for MB-COMT over S-COMT orient in the membrane in a fashion conducive to catalysis from the membrane surface and (2) binding of COMT to its cofactor ADOMET induces conformational change that drives the catalytic surface of the protein to the membrane surface, where the substrates and Mg2+ ions, required for catalysis, are found. Bioinformatics analysis reveals evidence of this mechanism in other proteins, including several existing drug targets. The development of new COMT inhibitors with preferential affinity for MB-COMT over S-COMT is now possible and insight of broader relevance, into the function of bitopic enzymes, is provided.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Universite de Geneve
Contributors: Magarkar, A., Parkkila, P., Viitala, T., Lajunen, T., Mobarak, E., Licari, G., Cramariuc, O., Vauthey, E., Róg, T., Bunker, A.
Number of pages: 4
Pages: 3440-3443
Publication date: 11 Apr 2018
Peer-reviewed: Yes

Publication information

Journal: Chemical Communications
Volume: 54
Issue number: 28
ISSN (Print): 1359-7345
Ratings: 
  • Scopus rating (2018): CiteScore 11.6 SJR 2.177 SNIP 1.145
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
Source: Scopus
Source ID: 85044968200

Research output: Contribution to journalArticleScientificpeer-review

Uncertainty in multispectral lidar signals caused by incidence angle effects

Multispectral terrestrial laser scanning (TLS) is an emerging technology. Several manufacturers already offer commercial dual or three wavelength airborne laser scanners, while multispectral TLS is still carried out mainly with research instruments. Many of these research efforts have focused on the study of vegetation. The aim of this paper is to study the uncertainty of the measurement of spectral indices of vegetation with multispectral lidar. Using two spectral indices as examples, we find that the uncertainty is due to systematic errors caused by the wavelength dependency of laser incidence angle effects. This finding is empirical, and the error cannot be removed by modelling or instrument modification. The discovery and study of these effects has been enabled by hyperspectral and multispectral TLS, and it has become a subject of active research within the past few years. We summarize the most recent studies on multi-wavelength incidence angle effects and present new results on the effect of specular reflection from the leaf surface, and the surface structure, which have been suggested to play a key role. We also discuss the consequences to the measurement of spectral indices with multispectral TLS, and a possible correction scheme using a synthetic laser footprint.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Mathematics, Department of Navigation and Positioning, FGI
Contributors: Kaasalainen, S., Åkerblom, M., Nevalainen, O., Hakala, T., Kaasalainen, M.
Publication date: 6 Apr 2018
Peer-reviewed: Yes

Publication information

Journal: Interface Focus
Volume: 8
Issue number: 2
Article number: 20170033
ISSN (Print): 2042-8898
Ratings: 
  • Scopus rating (2018): CiteScore 5.8 SJR 1.138 SNIP 0.95
Original language: English
ASJC Scopus subject areas: Biotechnology, Biophysics, Bioengineering, Biochemistry, Biomaterials, Biomedical Engineering
Keywords: Hyperspectral, Incidence angle, Laser scanning, Vegetation
Electronic versions: 
Source: Scopus
Source ID: 85043458754

Research output: Contribution to journalArticleScientificpeer-review

Non-intersecting leaf insertion algorithm for tree structure models

We present an algorithm and an implementation to insert broadleaves or needleleaves into a quantitative structure model according to an arbitrary distribution, and a data structure to store the required information efficiently. A structure model contains the geometry and branching structure of a tree. The purpose of this work is to offer a tool for making more realistic simulations of tree models with leaves, particularly for tree models developed from terrestrial laser scanning (TLS) measurements. We demonstrate leaf insertion using cylinder-based structure models, but the associated software implementation is written in a way that enables the easy use of other types of structure models. Distributions controlling leaf location, size and angles as well as the shape of individual leaves are user definable, allowing any type of distribution. The leaf generation process consist of two stages, the first of which generates individual leaf geometry following the input distributions, while in the other stage intersections are prevented by carrying out transformations when required. Initial testing was carried out on English oak trees to demonstrate the approach and to assess the required computational resources. Depending on the size and complexity of the tree, leaf generation takes between 6 and 18 min. Various leaf area density distributions were defined, and the resulting leaf covers were compared with manual leaf harvesting measurements. The results are not conclusive, but they show great potential for the method. In the future, if our method is demonstrated to work well for TLS data from multiple tree types, the approach is likely to be very useful for three-dimensional structure and radiative transfer simulation applications, including remote sensing, ecology and forestry, among others.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Mathematics, Forest Research, Department of Applied Health Research, NERC National Centre for Earth Observation (NCEO), University of Salford, Newcastle University, United Kingdom, York St John University
Contributors: Åkerblom, M., Raumonen, P., Casella, E., Disney, M. I., Danson, F. M., Gaulton, R., Schofield, L. A., Kaasalainen, M.
Publication date: 6 Apr 2018
Peer-reviewed: Yes

Publication information

Journal: Interface Focus
Volume: 8
Issue number: 2
Article number: 20170045
ISSN (Print): 2042-8898
Ratings: 
  • Scopus rating (2018): CiteScore 5.8 SJR 1.138 SNIP 0.95
Original language: English
ASJC Scopus subject areas: Biotechnology, Biophysics, Bioengineering, Biochemistry, Biomaterials, Biomedical Engineering
Keywords: Laser scanning, Leaf distribution, Leaf insertion, Quantitative structure model, Tree reconstruction
Electronic versions: 
Source: Scopus
Source ID: 85043466694

Research output: Contribution to journalArticleScientificpeer-review

Weighing trees with lasers: Advances, challenges and opportunities

Terrestrial laser scanning (TLS) is providing exciting new ways to quantify tree and forest structure, particularly above-ground biomass (AGB). We show how TLS can address some of the key uncertainties and limitations of current approaches to estimating AGB based on empirical allometric scaling equations (ASEs) that underpin all large-scale estimates of AGB. TLS provides extremely detailed non-destructive measurements of tree form independent of tree size and shape. We show examples of three-dimensional (3D) TLS measurements from various tropical and temperate forests and describe how the resulting TLS point clouds can be used to produce quantitative 3D models of branch and trunk size, shape and distribution. These models can drastically improve estimates of AGB, provide new, improved large-scale ASEs, and deliver insights into a range of fundamental tree properties related to structure. Large quantities of detailed measurements of individual 3D tree structure also have the potential to open new and exciting avenues of research in areas where difficulties of measurement have until now prevented statistical approaches to detecting and understanding underlying patterns of scaling, form and function. We discuss these opportunities and some of the challenges that remain to be overcome to enable wider adoption of TLS methods.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Mathematics, Department of Applied Health Research, NERC National Centre for Earth Observation (NCEO), National Physical Laboratory, Universiteit Gent, School of Geography, University of Leeds
Contributors: Disney, M. I., Boni Vicari, M., Burt, A., Calders, K., Lewis, S. L., Raumonen, P., Wilkes, P.
Publication date: 6 Apr 2018
Peer-reviewed: Yes

Publication information

Journal: Interface Focus
Volume: 8
Issue number: 2
Article number: 20170048
ISSN (Print): 2042-8898
Ratings: 
  • Scopus rating (2018): CiteScore 5.8 SJR 1.138 SNIP 0.95
Original language: English
ASJC Scopus subject areas: Biotechnology, Biophysics, Bioengineering, Biochemistry, Biomaterials, Biomedical Engineering
Keywords: Above-ground biomass, Buttress, Canopy, Lidar, Structure, Terrestrial laser scanning
Electronic versions: 

Bibliographical note

EXT="Lewis, S. L."

Source: Scopus
Source ID: 85043466280

Research output: Contribution to journalArticleScientificpeer-review

Aqueous synthesis of Z-scheme photocatalyst powders and thin-film photoanodes from earth abundant elements

Solid-state narrow band gap semiconductor heterostructures with a Z-scheme charge-transfer mechanism are the most promising photocatalytic systems for water splitting and environmental remediation under visible light. Herein, we construct all-solid Z-scheme photocatalytic systems from earth abundant elements (Ca and Fe) using an aqueous synthesis procedure. A novel Z-scheme two-component Fe2O3/Ca2Fe2O5 heterostructure is obtained in a straightforward manner by soaking various iron-containing nanoparticles (amorphous and crystalline) with Ca(NO3)2 and performing short (20min) thermal treatments at 820°C. The obtained powder materials show high photocatalytic performances for methylene blue dye degradation under visible light (45 mW/cm2), exhibiting a rate constant up to 0.015min-1. The heterostructure exhibits a five-fold higher activity compared to that of pristine hematite. The experiments show that amorphous iron-containing substrate nanoparticles trigger the Fe2O3/Ca2Fe2O5 heterostructure formation. We extended our study to produce Fe2O3/Ca2Fe2O5 nanoheterostructure photoanodes via the electrochemical deposition of amorphous iron-containing sediment were used. The visible-light (15mW/cm2) photocurrent increases from 183μA/cm2 to 306μA/cm2 after coupling hematite and Ca2Fe2O5. Notably, the powders and photoanodes exhibit distinct charge-transfer mechanisms evidenced by the different stabilities of the heterostructures under different working conditions.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Photonics, Riga Technical University, Institute of Physics, University of Tartu, Institute of Solid State Physics University of Latvia, Riga Technical University
Contributors: Šutka, A., Vanags, M., Joost, U., Šmits, K., Ruža, J., Ločs, J., Kleperis, J., Juhna, T.
Number of pages: 10
Pages: 2606-2615
Publication date: 1 Apr 2018
Peer-reviewed: Yes

Publication information

Journal: Journal of Environmental Chemical Engineering
Volume: 6
Issue number: 2
ISSN (Print): 2213-3437
Ratings: 
  • Scopus rating (2018): CiteScore 5.3 SJR 0.876 SNIP 1.219
Original language: English
ASJC Scopus subject areas: Chemical Engineering (miscellaneous), Waste Management and Disposal, Pollution, Process Chemistry and Technology
Keywords: Hematite, Photoanode, Photocatalyst, Photoelectrochemical properties, Z-scheme

Bibliographical note

INT=fot, ”Joost, U.”

Source: Scopus
Source ID: 85045209610

Research output: Contribution to journalArticleScientificpeer-review

Soft hydrazone crosslinked hyaluronan- and alginate-based hydrogels as 3D supportive matrices for human pluripotent stem cell-derived neuronal cells

Regenerative medicine, especially cell therapy combined with a supportive biomaterial scaffold, is considered to be a potential treatment for various deficits in humans. Here, we have produced and investigated the detailed properties of injectable hydrazone crosslinked hyaluronan-polyvinyl alcohol (HA-PVA) and alginate-polyvinyl alcohol (AL-PVA) hydrogels to be used as a supportive biomaterial for 3D neural cell cultures. To the best of our knowledge, this is the first time the polymerization and properties of hydrazone crosslinked AL-PVA hydrogel have been reported. The effect of the degree of substitution and molecular weight of the polymer components as well as the polymer concentration of the hydrogel on the swelling, degradation and mechanical properties of the hydrogels is reported. Furthermore, we studied the effect of the above parameters on the growth of human pluripotent stem cell-derived neuronal cells. The most neural cell supportive HA-PVA hydrogel was composed of high molecular weight HA component with brain-mimicking mechanical properties and decreased polymer concentration. AL-PVA hydrogel, with stiffness quite similar to brain tissue, was also shown to be similarly supportive. Neuronal spreading and 3D network formation was enhanced inside the softest hydrogels.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Faculty of Biomedical Sciences and Engineering, Research group: Biomaterials and Tissue Engineering Group, BioMediTech Institute and Faculty of Medicine and Life Sciences
Contributors: Karvinen, J., Joki, T., Ylä-Outinen, L., Koivisto, J. T., Narkilahti, S., Kellomäki, M.
Number of pages: 11
Pages: 29-39
Publication date: 1 Mar 2018
Peer-reviewed: Yes

Publication information

Journal: Reactive and Functional Polymers
Volume: 124
ISSN (Print): 1381-5148
Ratings: 
  • Scopus rating (2018): CiteScore 4.9 SJR 0.712 SNIP 0.92
Original language: English
ASJC Scopus subject areas: Chemistry(all), Environmental Chemistry, Biochemistry, Chemical Engineering(all), Polymers and Plastics, Materials Chemistry
Keywords: 3D neuronal culture, Alginate, Hyaluronan, Hydrazone, Hydrogel
Source: Scopus
Source ID: 85040229275

Research output: Contribution to journalArticleScientificpeer-review

Improved Stability of Atomic Layer Deposited Amorphous TiO2 Photoelectrode Coatings by Thermally Induced Oxygen Defects

Amorphous titanium dioxide (a-TiO2) combined with an electrocatalyst has shown to be a promising coating for stabilizing traditional semiconductor materials used in artificial photosynthesis for efficient photoelectrochemical solar-to-fuel energy conversion. In this study we report a detailed analysis of two methods of modifying an undoped thin film of atomic layer deposited (ALD) a-TiO2 without an electrocatalyst to affect its performance in water splitting reaction as a protective photoelectrode coating. The methods are high-temperature annealing in ultrahigh vacuum and atomic hydrogen exposure. A key feature in both methods is that they preserve the amorphous structure of the film. Special attention is paid to the changes in the molecular and electronic structure of a-TiO2 induced by these treatments. On the basis of the photoelectrochemical results, the a-TiO2 is susceptible to photocorrosion but significant improvement in stability is achieved after heat treatment in vacuum at temperatures above 500 °C. On the other hand, the hydrogen treatment does not increase the stability despite the ostensibly similar reduction of a-TiO2. The surface analysis allows us to interpret the improved stability to the thermally induced formation of O- species within a-TiO2 that are essentially electronic defects in the anionic framework.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Photonics, Materials Science
Contributors: Hannula, M., Ali-Löytty, H., Lahtonen, K., Sarlin, E., Saari, J., Valden, M.
Number of pages: 10
Pages: 1199-1208
Publication date: 27 Feb 2018
Peer-reviewed: Yes

Publication information

Journal: Chemistry of Materials
Volume: 30
Issue number: 4
ISSN (Print): 0897-4756
Ratings: 
  • Scopus rating (2018): CiteScore 16.4 SJR 4.224 SNIP 1.797
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all), Materials Chemistry
Electronic versions: 
Source: Scopus
Source ID: 85042704048

Research output: Contribution to journalArticleScientificpeer-review

Improved fatty aldehyde and wax ester production by overexpression of fatty acyl-CoA reductases

Background: Fatty aldehydes are industrially relevant compounds, which also represent a common metabolic intermediate in the microbial synthesis of various oleochemicals, including alkanes, fatty alcohols and wax esters. The key enzymes in biological fatty aldehyde production are the fatty acyl-CoA/ACP reductases (FARs) which reduce the activated acyl molecules to fatty aldehydes. Due to the disparity of FARs, identification and in vivo characterization of reductases with different properties are needed for the construction of tailored synthetic pathways for the production of various compounds. Results: Fatty aldehyde production in Acinetobacter baylyi ADP1 was increased by the overexpression of three different FARs: a native A. baylyi FAR Acr1, a cyanobacterial Aar, and a putative, previously uncharacterized dehydrogenase (Ramo) from Nevskia ramosa. The fatty aldehyde production was followed in real-time inside the cells with a luminescence-based tool, and the highest aldehyde production was achieved with Aar. The fate of the overproduced fatty aldehydes was studied by measuring the production of wax esters by a native downstream pathway of A. baylyi, for which fatty aldehyde is a specific intermediate. The wax ester production was improved with the overexpression of Acr1 or Ramo compared to the wild type A. baylyi by more than two-fold, whereas the expression of Aar led to only subtle wax ester production. The overexpression of FARs did not affect the length of the acyl chains of the wax esters. Conclusions: The fatty aldehyde production, as well as the wax ester production of A. baylyi, was improved with the overexpression of a key enzyme in the pathway. The wax ester titer (0.45 g/l) achieved with the overexpression of Acr1 is the highest reported without hydrocarbon supplementation to the culture. The contrasting behavior of the different reductases highlight the significance of in vivo characterization of enzymes and emphasizes the possibilities provided by the diversity of FARs for pathway and product modulation.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy
Contributors: Lehtinen, T., Efimova, E., Santala, S., Santala, V.
Publication date: 8 Feb 2018
Peer-reviewed: Yes

Publication information

Journal: Microbial Cell Factories
Volume: 17
Issue number: 1
Article number: 19
ISSN (Print): 1475-2859
Ratings: 
  • Scopus rating (2018): CiteScore 6.9 SJR 1.407 SNIP 1.272
Original language: English
ASJC Scopus subject areas: Biotechnology, Bioengineering, Applied Microbiology and Biotechnology
Keywords: Acinetobacter baylyi ADP1, FAR, Fatty acyl-CoA reductase, Fatty aldehyde, Wax ester
Electronic versions: 
Source: Scopus
Source ID: 85041848256

Research output: Contribution to journalArticleScientificpeer-review

Design, synthesis, and structure-property relationships of Er3+ -doped TiO2 luminescent particles synthesized by sol-gel

Titania particles doped with various concentrations of Erbium were synthesized by the sol-gel method followed by different heat treatments. The shape and the grain growth of the particles were noticeably affected by the concentration of Erbium and the heat treatment conditions. An infrared emission at 1530 nm, as well as green and red up-conversion emissions at 550 and 670 nm, were observed under excitation at 976 nm from all of the synthesized particles. The emission spectra and lifetime values appeared to be strongly influenced by the presence of the different crystalline phases. This work presents important guidelines for the synthesis of functional Er3+ -doped titania particles with controlled and tailored spectroscopic properties for photonic applications.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Photonics, Research group: Photonics Glasses, Politecnico di Torino, Istituto Superiore Mario Boella, CERICOL, nLIGHT Corporation, Centro S3
Contributors: Lopez-Iscoa, P., Pugliese, D., Boetti, N. G., Janner, D., Baldi, G., Petit, L., Milanese, D.
Publication date: 2 Jan 2018
Peer-reviewed: Yes

Publication information

Journal: Nanomaterials
Volume: 8
Issue number: 1
Article number: 20
ISSN (Print): 2079-4991
Ratings: 
  • Scopus rating (2018): CiteScore 3.5 SJR 0.896 SNIP 1.144
Original language: English
ASJC Scopus subject areas: Materials Science(all), Chemical Engineering(all)
Keywords: Erbium-doped titania, Photoluminescence, Sol-gel synthesis
Electronic versions: 
Source: Scopus
Source ID: 85041603664

Research output: Contribution to journalArticleScientificpeer-review

Upconversion from fluorophosphate glasses prepared with NaYF4:Er3+,Yb3+nanocrystals

The direct doping method was applied to fabricate upconverter fluorophosphate glasses in the system (90NaPO3-(10-x)Na2O-xNaF) (mol%) by adding NaYF4:Er3+,Yb3+ nanocrystals. An increase in the network connectivity, a red shift of the optical band gap and a decrease in the thermal properties occur when Na2O is progressively replaced by NaF. To ensure the survival and the dispersion of the nanocrystals in the glasses with x = 0 and 10, three doping temperatures (Tdoping) (525, 550 and 575 °C) at which the nanocrystals were added in the glass melt after melting and 2 dwell times (3 and 5 minutes) before quenching the glasses were tested. Using 5 wt% of the NaYF4:Er3+,Yb3+ nanocrystals, green emission from the NaYF4:Er3+,Yb3+ nanocrystals-containing glasses was observed using a 980 nm pumping, the intensity of which depends on the glass composition and on the direct doping parameters (Tdoping and dwell time). The strongest upconversion was obtained from the glass with x = 10 prepared using a Tdoping of 550 °C and a 3 min dwell time. Finally, we showed that the upconversion, the emission at 1.5 μm and of the transmittance spectra of the nanocrystals-containing glasses could be measured to verify if decomposition of the nanocrystals occurred in glass melts during the preparation of the glasses.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Photonics, University of Turku
Contributors: Ojha, N., Tuomisto, M., Lastusaari, M., Petit, L.
Number of pages: 11
Pages: 19226-19236
Publication date: 1 Jan 2018
Peer-reviewed: Yes

Publication information

Journal: RSC Advances
Volume: 8
Issue number: 34
ISSN (Print): 2046-2069
Ratings: 
  • Scopus rating (2018): CiteScore 6.5 SJR 0.807 SNIP 0.799
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all)
Electronic versions: 
Source: Scopus
Source ID: 85047563423

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 2.9 SJR 0.818 SNIP 0.998
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

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 12.5 SJR 2.066 SNIP 1.962
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

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 7 SJR 1.624 SNIP 1.962
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

Regeneration of sulfur-poisoned Pd-based catalyst for natural gas oxidation

Sulfur deactivation and regeneration behavior of the Pd/Al2O3 catalyst has been investigated via experimental characterization and density functional theory (DFT) simulations. During the sulfur exposure, PdO crystallites grow slightly while bulk Al2(SO4)3 forms on the support. DFT calculations indicate that SOx species interact strongly with the catalyst surface making it chemically inactive in agreement with the experimental results. During the regeneration treatment (CH4 conditions), PdO particles reduce, Al2(SO4)3 is partially removed, and the activity for CH4 conversion is increased. No full recovery can be observed due to remaining Al2(SO4)3, the formation of encapsulating sulfur species, and the partial reduction of PdO particles. To reoxidize Pd, the catalyst is further regenerated (O2 conditions). The resulting CH4 conversion is at the same level than with the regenerated catalyst. Thus, a small amount of Al2(SO4)3 appears to have a stronger effect on the performance than the state of Pd.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science, Research group: Materials Characterization, Physics, Research area: Computational Physics, Research group: Materials and Molecular Modeling, Univ of Oulu, Aalto University, Dinex Ecocat Oy, Norwegian University of Science and Technology
Contributors: Honkanen, M., Wang, J., Kärkkäinen, M., Huuhtanen, M., Jiang, H., Kallinen, K., Keiski, R. L., Akola, J., Vippola, M.
Number of pages: 13
Pages: 253-265
Publication date: 2018
Peer-reviewed: Yes
Early online date: 4 Jan 2018

Publication information

Journal: Journal of Catalysis
Volume: 358
ISSN (Print): 0021-9517
Ratings: 
  • Scopus rating (2018): CiteScore 11.3 SJR 2.254 SNIP 1.756
Original language: English
ASJC Scopus subject areas: Catalysis, Physical and Theoretical Chemistry
Keywords: Catalytic testing, Density functional theory simulations, Fourier transform infrared spectrometry, Pd-based catalyst, Regeneration, Sulfur poisoning, Transmission electron microscopy
Source: Scopus
Source ID: 85039986144

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 6.5 SJR 0.807 SNIP 0.799
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

Decomposition of persistent luminescent microparticles in corrosive phosphate glass melt

Findings on the decomposition of persistent luminescent (PeL) SrAl2O4:Eu2+,Dy3+ microparticles (MPs) in phosphate glass melt under static condition are reported. PeL phosphate glasses with the composition (50P2O5-10Na2O-40SrO) (in mol%) were prepared by adding the MPs in the glass melt. The decomposition of the MPs occurs during the preparation of the glass and leads to changes in the Eu2+ sites and to the formation of Eu3+ which decreases the PeL properties of the glasses. The decomposition of the MPs depends on the temperature at which the MPs are added in the melt and also on the time before casting the melts.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Photonics, Research group: Nanophotonics, Turun Yliopisto/Turun Biomateriaalikeskus
Contributors: Ojha, N., Nguyen, H., Laihinen, T., Salminen, T., Lastusaari, M., Petit, L.
Pages: 207-214
Publication date: 2018
Peer-reviewed: Yes

Publication information

Journal: Corrosion Science
Volume: 135
ISSN (Print): 0010-938X
Ratings: 
  • Scopus rating (2018): CiteScore 10.3 SJR 2.131 SNIP 2.759
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all), Materials Science(all)
Keywords: Corrosion, Decomposition, Persistent luminescence, Phosphate glasses, SrAlO:Eu,Dy microparticles

Bibliographical note

INT=fot,"Nguyen, H."

Source: Scopus
Source ID: 85042665831

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): CiteScore 4.7 SJR 0.754 SNIP 1.043
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

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 11.6 SJR 2.177 SNIP 1.145
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

Bioactive glass induced osteogenic differentiation of human adipose stem cells is dependent on cell attachment mechanism and mitogen-activated protein kinases

Bioactive glasses (BaGs) are widely utilised in bone tissue engineering (TE) but the molecular response of cells to BaGs is poorly understood. To elucidate the mechanisms of cell attachment to BaGs and BaG-induced early osteogenic differentiation, we cultured human adipose stem cells (hASCs) on discs of two silica-based BaGs S53P4 (23.0 Na2O-20.0 CaO-4.0 P2O5-53.0 SiO2 (wt-%)) and 1-06 (5.9 Na2O-12.0 K2O-5.3 MgO-22.6 CaO-4.0 P2O5-0.2 B2O3-50.0 SiO2) in the absence of osteogenic supplements. Both BaGs induced early osteogenic differentiation by increasing alkaline phosphatase activity (ALP) and the expression of osteogenic marker genes RUNX2a and OSTERIX. Based on ALP activity, the slower reacting 1-06 glass was a stronger osteoinducer. Regarding the cell attachment, cells cultured on BaGs had enhanced integrinβ1 and vinculin production, and mature focal adhesions were smaller but more dispersed than on cell culture plastic (polystyrene). Focal adhesion kinase (FAK), extracellular signal-regulated kinase (ERK1/2) and c-Jun N-terminal kinase (JNK)-induced c-Jun phosphorylations were upregulated by glass contact. Moreover, the BaG-stimulated osteoinduction was significantly reduced by FAK and mitogen-activated protein kinase (MAPK) inhibitors, indicating an important role for FAK and MAPKs in the BaG-induced early osteogenic commitment of hASCs. Upon indirect insert culture, the ions released from the BaG discs could not reproduce the observed cellular changes, which highlighted the role of direct cell-BaG interactions in the osteopotential of BaGs. These findings gave valuable insight into the mechanism of BaG-induced osteogenic differentiation and therefore provided knowledge to aid the future design of new functional biomaterials to meet the increasing demand for clinical bone TE treatments.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Faculty of Biomedical Sciences and Engineering, The National Science Centre, Poland, Tampere University Hospital, Johan Gadolin Process Chemistry Centre, Abo Akademi University, University of Tampere
Contributors: Ojansivu, M., Wang, X., Hyväri, L., Kellomäki, M., Hupa, L., Vanhatupa, S., Miettinen, S.
Number of pages: 19
Pages: 53-71
Publication date: 2018
Peer-reviewed: Yes

Publication information

Journal: European Cells and Materials
Volume: 35
ISSN (Print): 1473-2262
Ratings: 
  • Scopus rating (2018): CiteScore 6.4 SJR 1.171 SNIP 1.062
Original language: English
ASJC Scopus subject areas: Bioengineering, Biochemistry, Biomaterials, Biomedical Engineering, Cell Biology
Keywords: Bioactive glass, Cell attachment, Cell signalling, Focal adhesion, Mesenchymal stem cell, Mitogen-activated protein kinase, Osteogenic differentiation

Bibliographical note

EXT="Ojansivu, M."
EXT="Vanhatupa, S."

Source: Scopus
Source ID: 85052576307

Research output: Contribution to journalArticleScientificpeer-review

Deactivation of Pt/SiO2-ZrO2 diesel oxidation catalysts by sulphur, phosphorus and their combinations

The impact of sulphur, phosphorus and water and their co-exposure on a monolith-type Pt/SiO2-ZrO2 diesel oxidation catalyst was investigated. The accelerated laboratory-scale sulphur treatments for Pt/SiO2-ZrO2 were done with and without water (S- and SW-treatments, respectively) at 400 °C. Similarly, the phosphorus treatment with water (PW-treatment) as well as the co-exposure of phosphorus, sulphur and water (PSW-treatment) were also done to find out the interactions between the impurities. The studied catalysts were characterized by using several techniques and the activity of the catalyst was tested in lean diesel exhaust gas conditions. Based on the XPS and the elemental analysis, more phosphorus was adsorbed on the Pt/SiO2-ZrO2 catalyst than sulphur. Sulphur, in the presence and absence of water, was found to have a negligible effect on the CO and C3H6 light-off temperatures (T90) over the fresh Pt/SiO2-ZrO2, whereas the T90 values of CO and C3H6 increased by 30–45 °C as a result of the PW-treatment and by 15–35 °C after the PSW-treatment. Based on the Transmission electron microscope (TEM) analyses, no morphological changes on the Pt/SiO2-ZrO2 surfaces were observed due to the phosphorus treatment. Therefore, the reason for the lower activity after the PW-treatment could be the formation of phosphates that are decreasing the specific surface area of the catalyst, blocking the accessibility of the reactants to the catalyst pores and active sites. However, it is worth noting that sulphur decreased the amount of adsorbed phosphorus and thus, inhibited the poisoning effect of phosphorus.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science, Research group: Materials Characterization, Dinex Ecocat Oy, Univ of Oulu, Aalto University
Contributors: Väliheikki, A., Kärkkäinen, M., Honkanen, M., Heikkinen, O., Kolli, T., Kallinen, K., Huuhtanen, M., Vippola, M., Lahtinen, J., Keiski, R. L.
Number of pages: 11
Pages: 409-419
Publication date: 5 Dec 2017
Peer-reviewed: Yes

Publication information

Journal: Applied Catalysis B-Environmental
Volume: 218
ISSN (Print): 0926-3373
Ratings: 
  • Scopus rating (2017): CiteScore 17.3 SJR 3.152 SNIP 2.367
Original language: English
ASJC Scopus subject areas: Catalysis, Environmental Science(all), Process Chemistry and Technology
Keywords: DOC, Phosphorus, Platinum, Silicon-zirconium oxide, Sulphur dioxide
Source: Scopus
Source ID: 85021933594

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 5.6 SJR 0.819 SNIP 1.009
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

Oxygen and water vapor transmission rates of starch-poly(vinyl alcohol) barrier coatings for flexible packaging paper

Creating efficient water-borne dispersions based mainly on renewable materials for coating of flexible packaging paper was the aim of this study. The effects of an ethylene modified poly(vinyl alcohol) grade and a standard poly(vinyl alcohol) on the oxygen and water vapor barrier performance of corn starch and potato starch coatings was studied. The results showed that a coating composition with a high fraction of a renewable polymer was effective in keeping the oxygen barrier at a technically and commercially applicable level. An ethylene modified poly(vinyl alcohol) grade was found to provide lower oxygen transmission rates at high relative humidity, as compared to a standard poly(vinyl alcohol) grade. The oxygen barrier properties of blends of starch and poly(vinyl alcohol) were similar to that of the pure modified poly(vinyl alcohol) in the range from 0% starch to 60% starch. This was observed with both hydroxypropylated and octenyl succinate modified starch grades. The drying conditions of the mixed starch:poly(vinyl alcohol) coatings were based on drying trials with pure poly(vinyl alcohol) coatings. Drying at moderate temperatures indicated the possibility to slightly decrease water vapor transmission rate by higher drying temperature. Several secondary effects of increased drying temperature such as coating hold-out and formation of defects may also be of importance.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Karlstad University
Contributors: Christophliemk, H., Johansson, C., Ullsten, H., Järnström, L.
Number of pages: 7
Pages: 218-224
Publication date: 1 Dec 2017
Peer-reviewed: Yes

Publication information

Journal: Progress in Organic Coatings
Volume: 113
ISSN (Print): 0300-9440
Ratings: 
  • Scopus rating (2017): CiteScore 5.1 SJR 0.844 SNIP 1.334
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Surfaces, Coatings and Films, Organic Chemistry, Materials Chemistry
Keywords: Barrier coating, Drying, Oxygen transmission rate, Poly(vinyl alcohol), Starch, Water vapor transmission rate
Source: Scopus
Source ID: 85019946529

Research output: Contribution to journalArticleScientificpeer-review

Production of long chain alkyl esters from carbon dioxide and electricity by a two-stage bacterial process

Microbial electrosynthesis (MES) is a promising technology for the reduction of carbon dioxide into value-added multicarbon molecules. In order to broaden the product profile of MES processes, we developed a two-stage process for microbial conversion of carbon dioxide and electricity into long chain alkyl esters. In the first stage, the carbon dioxide is reduced to organic compounds, mainly acetate, in a MES process by Sporomusa ovata. In the second stage, the liquid end-products of the MES process are converted to the final product by a second microorganism, Acinetobacter baylyi in an aerobic bioprocess. In this proof-of-principle study, we demonstrate for the first time the bacterial production of long alkyl esters (wax esters) from carbon dioxide and electricity as the sole sources of carbon and energy. The process holds potential for the efficient production of carbon-neutral chemicals or biofuels.

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, Wuhan University of Technology
Contributors: Lehtinen, T., Efimova, E., Tremblay, P. L., Santala, S., Zhang, T., Santala, V.
Number of pages: 7
Pages: 30-36
Publication date: 1 Nov 2017
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 243
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2017): CiteScore 10 SJR 2.029 SNIP 1.84
Original language: English
ASJC Scopus subject areas: Bioengineering
Keywords: Acinetobacter baylyi ADP1, Carbon dioxide fixation, Carbon neutral, Microbial electrosynthesis, Oleochemicals
Electronic versions: 
Source: Scopus
Source ID: 85021253675

Research output: Contribution to journalArticleScientificpeer-review

DoGlycans-Tools for Preparing Carbohydrate Structures for Atomistic Simulations of Glycoproteins, Glycolipids, and Carbohydrate Polymers for GROMACS

Carbohydrates constitute a structurally and functionally diverse group of biological molecules and macromolecules. In cells they are involved in, e.g., energy storage, signaling, and cell-cell recognition. All of these phenomena take place in atomistic scales, thus atomistic simulation would be the method of choice to explore how carbohydrates function. However, the progress in the field is limited by the lack of appropriate tools for preparing carbohydrate structures and related topology files for the simulation models. Here we present tools that fill this gap. Applications where the tools discussed in this paper are particularly useful include, among others, the preparation of structures for glycolipids, nanocellulose, and glycans linked to glycoproteins. The molecular structures and simulation files generated by the tools are compatible with GROMACS.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Research group: Biological Physics and Soft Matter, University of Helsinki, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, MEMPHYS - Centre for Biomembrane Physics, University of Southern Denmark, Laboratory of Physics
Contributors: Danne, R., Poojari, C., Martinez-Seara, H., Rissanen, S., Lolicato, F., Róg, T., Vattulainen, I.
Number of pages: 6
Pages: 2401-2406
Publication date: 23 Oct 2017
Peer-reviewed: Yes

Publication information

Journal: Journal of Chemical Information and Modeling
Volume: 57
Issue number: 10
ISSN (Print): 1549-9596
Ratings: 
  • Scopus rating (2017): CiteScore 6.9 SJR 1.349 SNIP 1.213
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all), Computer Science Applications, Library and Information Sciences
Source: Scopus
Source ID: 85031999962

Research output: Contribution to journalArticleScientificpeer-review

Starch-poly(vinyl alcohol) barrier coatings for flexible packaging paper and their effects of phase interactions

Starch and poly(vinyl alcohol) based barrier coatings for flexible packaging papers were studied. Both octenyl succinate modified and hydroxypropylated corn and potato starches were blended with regular and ethylene modified poly(vinyl alcohol) to increase the water vapor barrier properties and enhance the flexibility of the starch coatings, in order to accomplish superior barrier performance. Phase separation between starch and poly(vinyl alcohol) was studied in detail, both in the solution and in dry draw-down coatings on paper. The barrier performance of the coated paper was evaluated with respect to water vapor transmission rate. Conditions for the creation of a thin surface layer consisting of only one of the pure polymers were identified and discussed in terms of phase separation in solution migration of poly(vinyl alcohol) to the uppermost surface layer. The phase separation promoted low water vapor transmission rates also with a rather high fraction of starch in the coatings.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Karlstad University
Contributors: Christophliemk, H., Ullsten, H., Johansson, C., Järnström, L.
Number of pages: 10
Pages: 13-22
Publication date: 1 Oct 2017
Peer-reviewed: Yes

Publication information

Journal: Progress in Organic Coatings
Volume: 111
ISSN (Print): 0300-9440
Ratings: 
  • Scopus rating (2017): CiteScore 5.1 SJR 0.844 SNIP 1.334
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Surfaces, Coatings and Films, Organic Chemistry, Materials Chemistry
Keywords: Barrier coating, PVOH, Starch, Turbidity, Viscosity, WVTR, XPS
Source: Scopus
Source ID: 85019450052

Research output: Contribution to journalArticleScientificpeer-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 4.3 SJR 0.584 SNIP 1.593
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

Membrane Binding of Recoverin: From Mechanistic Understanding to Biological Functionality

Recoverin is a neuronal calcium sensor involved in vision adaptation that reversibly associates with cellular membranes via its calcium-activated myristoyl switch. While experimental evidence shows that the myristoyl group significantly enhances membrane affinity of this protein, molecular details of the binding process are still under debate. Here, we present results of extensive molecular dynamics simulations of recoverin in the proximity of a phospholipid bilayer. We capture multiple events of spontaneous membrane insertion of the myristoyl moiety and confirm its critical role in the membrane binding. Moreover, we observe that the binding strongly depends on the conformation of the N-terminal domain. We propose that a suitable conformation of the N-terminal domain can be stabilized by the disordered C-terminal segment or by binding of the target enzyme, i.e., rhodopsin kinase. Finally, we find that the presence of negatively charged lipids in the bilayer stabilizes a physiologically functional orientation of the membrane-bound recoverin.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Institute of Experimental Botany of the Academy of Sciences of the Czech Republic, University of Stuttgart, University of Helsinki
Contributors: Timr, Š., Pleskot, R., Kadlec, J., Kohagen, M., Magarkar, A., Jungwirth, P.
Number of pages: 7
Pages: 868-874
Publication date: 23 Aug 2017
Peer-reviewed: Yes

Publication information

Journal: ACS Central Science
Volume: 3
Issue number: 8
ISSN (Print): 2374-7943
Ratings: 
  • Scopus rating (2017): CiteScore 7.7 SJR 5.022 SNIP 1.991
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Chemistry(all)
Source: Scopus
Source ID: 85028063042

Research output: Contribution to journalArticleScientificpeer-review

Exhaust emissions of non-road mobile machine: Real-world and laboratory studies with diesel and HVO fuels

Exhaust emissions emitted by a non-road mobile machine were studied chasing a tractor in real-world conditions and repeating the same transient tests with a similar engine on an engine dynamometer where additionally, non-road steady state tests were carried out. The engines were equipped with an oxidation catalyst (DOC) and a selective catalytic reduction (SCR) system, and they were fuelled by fossil diesel fuel with ultra-low sulphur content and hydrotreated vegetable oil (HVO). By substituting diesel fuel with HVO the on-road emissions of nitrogen oxides (NOx) reduced 20% and particle number 44%, the emission factors being EFNOx = 1.62 ± 0.04 g/kWh and EFN = (28.2 ± 7.8) × 1013 #/kWh. Similar trend was observed for NOx at laboratory although the emissions were somewhat smaller than on-road. In contrast to real-world, in the laboratory experiment the EFN was only 2% smaller with HVO than with diesel, and these emission factors were almost one order of magnitude smaller than observed on-road. The number size distribution and volatility measurements showed that in real-world experiments small nucleation mode particles were formed during uphill and during downhill in engine braking conditions. These were not observed at laboratory. However, nucleation mode particles were observed in the laboratory experiments at high load steady driving conditions. At steady state tests the emissions strongly depended on engine load and engine speed with both fuels.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Research area: Aerosol Physics, University of Helsinki, Turku University of Applied Sciences
Contributors: Pirjola, L., Rönkkö, T., Saukko, E., Parviainen, H., Malinen, A., Alanen, J., Saveljeff, H.
Number of pages: 11
Pages: 154-164
Publication date: 15 Aug 2017
Peer-reviewed: Yes

Publication information

Journal: Fuel
Volume: 202
ISSN (Print): 0016-2361
Ratings: 
  • Scopus rating (2017): CiteScore 8.8 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: Diesel engine, Exhaust emissions, HVO, NO, Particle size distribution, Real-world emissions, Tractor
Electronic versions: 
URLs: 
Source: Scopus
Source ID: 85017566506

Research output: Contribution to journalArticleScientificpeer-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 10 SJR 2.029 SNIP 1.84
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

Dissolution-induced nanowire synthesis on hot-dip galvanized surface in supercritical carbon dioxide

In this study, we demonstrate a rapid treatment method for producing a needle-like nanowire structure on a hot-dip galvanized sheet at a temperature of 50 C. The processing method involved only supercritical carbon dioxide and water to induce a reaction on the zinc surface, which resulted in growth of zinc hydroxycarbonate nanowires into flower-like shapes. This artificial patina nanostructure predicts high surface area and offers interesting opportunities for its use in industrial high-end applications. The nanowires can significantly improve paint adhesion and promote electrochemical stability for organic coatings, or be converted to ZnO nanostructures by calcining to be used in various semiconductor applications.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science, Research group: Ceramic materials, Top Analytica Oy, SSAB
Contributors: Kaleva, A., Saarimaa, V., Heinonen, S., Nikkanen, J., Markkula, A., Väisänen, P., Levänen, E.
Publication date: 11 Jul 2017
Peer-reviewed: Yes

Publication information

Journal: Nanomaterials
Volume: 7
Issue number: 7
Article number: 181
ISSN (Print): 2079-4991
Ratings: 
  • Scopus rating (2017): SNIP 0.947
Original language: English
ASJC Scopus subject areas: Materials Science(all), Chemical Engineering(all)
Keywords: Nanowire, Supercritical carbon dioxide, Zinc hydroxycarbonate
Electronic versions: 
Source: Scopus
Source ID: 85025460868

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 8.8 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

Electron microscopic studies of natural gas oxidation catalyst – Effects of thermally accelerated aging on catalyst microstructure

Structural changes of PtPd nanoparticles in a natural gas oxidation catalyst were studied at elevated temperatures in air and low-oxygen conditions and in situ using environmental transmission electron microscopy (ETEM). The fresh catalyst shows x particles on the γ-Al2O3 support. At 700 °C, the noble metal oxide decomposes and Pt gets trapped by PdO particles followed by formation of metallic Pd and Pt containing particles. At 1000 °C, the particles had a metallic Pd and Pt containing core surrounded by PdO particles. In addition, the presence of

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science, Research group: Materials Characterization, Danmarks Tekniske Universitet, DTU Informatik, Aalto University, Univ of Oulu, Dinex Ecocat Oy
Contributors: Honkanen, M., Hansen, T. W., Jiang, H., Kärkkäinen, M., Huuhtanen, M., Heikkinen, O., Kallinen, K., Lahtinen, J., Keiski, R. L., Wagner, J. B., Vippola, M.
Number of pages: 11
Pages: 19-29
Publication date: 1 May 2017
Peer-reviewed: Yes

Publication information

Journal: Journal of Catalysis
Volume: 349
ISSN (Print): 0021-9517
Ratings: 
  • Scopus rating (2017): CiteScore 11.4 SJR 2.397 SNIP 1.865
Original language: English
ASJC Scopus subject areas: Catalysis, Physical and Theoretical Chemistry
Keywords: Environmental transmission electron microscope, Low-oxygen conditions, Natural gas oxidation, Palladium, Platinum, Sintering, Thermal aging
Source: Scopus
Source ID: 85016079754

Research output: Contribution to journalArticleScientificpeer-review

Bioamine-crosslinked gellan gum hydrogel for neural tissue engineering

Neural tissue engineering and three-dimensional in vitro tissue modeling require the development of biomaterials that take into account the specified requirements of human neural cells and tissue. In this study, an alternative method of producing biomimetic hydrogels based on gellan gum (GG) was developed by replacing traditional crosslinking methods with the bioamines spermidine and spermine. These bioamines were proven to function as crosslinkers for GG hydrogel at +37 °C, allowing for the encapsulation of human neurons. We studied the mechanical and rheological properties of the formed hydrogels, which showed biomimicking properties comparable to naïve rabbit brain tissue under physiologically relevant stress and strain. Human pluripotent stem cell-derived neuronal cells demonstrated good cytocompatibility in the GG-based hydrogels. Moreover, functionalization of GG hydrogels with laminin resulted in cell type-specific behavior: neuronal cell maturation and neurite migration.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: BioMediTech, Faculty of Biomedical Sciences and Engineering, Research group: Biomaterials and Tissue Engineering Group, Materials Science, Research group: Plastics and Elastomer Technology, BioMediTech Institute and Faculty of Medicine and Life Sciences
Contributors: Koivisto, J. T., Joki, T., Parraga, J. E., Paakkönen, R., Yla-Outinen, L., Salonen, L., Jönkkäri, I., Peltola, M., Ihalainen, T. O., Narkilahti, S., Kellomäki, M.
Publication date: 24 Mar 2017
Peer-reviewed: Yes

Publication information

Journal: Biomedical Materials
Volume: 12
Issue number: 2
Article number: 025014
ISSN (Print): 1748-6041
Ratings: 
  • Scopus rating (2017): CiteScore 4.5 SJR 0.768 SNIP 0.8
Original language: English
ASJC Scopus subject areas: Bioengineering, Biomaterials, Biomedical Engineering
Keywords: 3D cell culture, gellan gum, human pluripotent stem cells, hydrogel, laminin, neuronal cells

Bibliographical note

EXT="Ihalainen, Teemu O."

Source: Scopus
Source ID: 85018274634

Research output: Contribution to journalArticleScientificpeer-review

Calcium Directly Regulates Phosphatidylinositol 4,5-Bisphosphate Headgroup Conformation and Recognition

The orchestrated recognition of phosphoinositides and concomitant intracellular release of Ca2+ is pivotal to almost every aspect of cellular processes, including membrane homeostasis, cell division and growth, vesicle trafficking, as well as secretion. Although Ca2+ is known to directly impact phosphoinositide clustering, little is known about the molecular basis for this or its significance in cellular signaling. Here, we study the direct interaction of Ca2+ with phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2), the main lipid marker of the plasma membrane. Electrokinetic potential measurements of PI(4,5)P2 containing liposomes reveal that Ca2+ as well as Mg2+ reduce the zeta potential of liposomes to nearly background levels of pure phosphatidylcholine membranes. Strikingly, lipid recognition by the default PI(4,5)P2 lipid sensor, phospholipase C delta 1 pleckstrin homology domain (PLC δ1-PH), is completely inhibited in the presence of Ca2+, while Mg2+ has no effect with 100 nm liposomes and modest effect with giant unilamellar vesicles. Consistent with biochemical data, vibrational sum frequency spectroscopy and atomistic molecular dynamics simulations reveal how Ca2+ binding to the PI(4,5)P2 headgroup and carbonyl regions leads to confined lipid headgroup tilting and conformational rearrangements. We rationalize these findings by the ability of calcium to block a highly specific interaction between PLC δ1-PH and PI(4,5)P2, encoded within the conformational properties of the lipid itself. Our studies demonstrate the possibility that switchable phosphoinositide conformational states can serve as lipid recognition and controlled cell signaling mechanisms.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, German Center for Diabetes Research (DZD e.V.), Institute of Experimental Botany of the Academy of Sciences of the Czech Republic, Pennsylvania State University, University of Wrocław, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, J. Heyrovský Institute of Physical Chemistry, University of Helsinki, MEMPHYS, University of Southern Denmark
Contributors: Bilkova, E., Pleskot, R., Rissanen, S., Sun, S., Czogalla, A., Cwiklik, L., Róg, T., Vattulainen, I., Cremer, P. S., Jungwirth, P., Coskun, Ü.
Number of pages: 6
Pages: 4019-4024
Publication date: 22 Mar 2017
Peer-reviewed: Yes

Publication information

Journal: Journal of the American Chemical Society
Volume: 139
Issue number: 11
ISSN (Print): 0002-7863
Ratings: 
  • Scopus rating (2017): CiteScore 24 SJR 8.127 SNIP 2.633
Original language: English
ASJC Scopus subject areas: Catalysis, Chemistry(all), Biochemistry, Colloid and Surface Chemistry

Bibliographical note

EXT="Cwiklik, Lukasz"

Source: Scopus
Source ID: 85016148911

Research output: Contribution to journalArticleScientificpeer-review

Hierarchical Self-Assembly of Halogen-Bonded Block Copolymer Complexes into Upright Cylindrical Domains

Self-assembly of block copolymers into well-defined, ordered arrangements of chemically distinct domains is a reliable strategy for preparing tailored nanostructures. Microphase separation results from the system, minimizing repulsive interactions between dissimilar blocks and maximizing attractive interactions between similar blocks. Supramolecular methods have also achieved this separation by introducing small-molecule additives binding specifically to one block by noncovalent interactions. Here, we use halogen bonding as a supramolecular tool that directs the hierarchical self-assembly of low-molecular-weight perfluorinated molecules and diblock copolymers. Microphase separation results in a lamellar-within-cylindrical arrangement and promotes upright cylindrical alignment in films upon rapid casting and without further annealing. Such cylindrical domains with internal lamellar self-assemblies can be cleaved by solvent treatment of bulk films, resulting in separated and segmented cylindrical micelles stabilized by halogen-bond-based supramolecular crosslinks. These features, alongside the reversible nature of halogen bonding, provide a robust modular approach for nanofabrication.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Supramolecular photochemistry, VTT Technical Research Centre of Finland, Aalto University, Politecnico di Milano, Italian Institute of Technology, Università del Salento
Contributors: Milani, R., Houbenov, N., Fernandez-Palacio, F., Cavallo, G., Luzio, A., Haataja, J., Giancane, G., Saccone, M., Priimägi, A., Metrangolo, P., Ikkala, O.
Number of pages: 10
Pages: 417-426
Publication date: 9 Mar 2017
Peer-reviewed: Yes

Publication information

Journal: CheM
Volume: 2
Issue number: 3
ISSN (Print): 2451-9294
Ratings: 
  • Scopus rating (2017): CiteScore 6.7 SJR 5.295 SNIP 2.265
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all), Biochemistry, Environmental Chemistry, Materials Chemistry, Biochemistry, medical
Keywords: block copolymers, halogen bond, hierarchical self-assembly, nanofabrication, supramolecular complexes
Source: Scopus
Source ID: 85014778403

Research output: Contribution to journalArticleScientificpeer-review

Benchmarking DFT methods with small basis sets for the calculation of halogen-bond strengths

In recent years, halogen bonding has become an important design tool in crystal engineering, supramolecular chemistry and biosciences. The fundamentals of halogen bonding have been studied extensively with high-accuracy computational methods. Due to its non-covalency, the use of triple-zeta (or larger) basis sets is often recommended when studying halogen bonding. However, in the large systems often encountered in supramolecular chemistry and biosciences, large basis sets can make the calculations far too slow. Therefore, small basis sets, which would combine high computational speed and high accuracy, are in great demand. This study focuses on comparing how well density functional theory (DFT) methods employing small, double-zeta basis sets can estimate halogen-bond strengths. Several methods with triple-zeta basis sets are included for comparison. Altogether, 46 DFT methods were tested using two data sets of 18 and 33 halogen-bonded complexes for which the complexation energies have been previously calculated with the high-accuracy CCSD(T)/CBS method. The DGDZVP basis set performed far better than other double-zeta basis sets, and it even outperformed the triple-zeta basis sets. Due to its small size, it is well-suited to studying halogen bonding in large systems.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Supramolecular photochemistry
Contributors: Siiskonen, A., Priimägi, A.
Publication date: 1 Feb 2017
Peer-reviewed: Yes

Publication information

Journal: Journal of Molecular Modeling
Volume: 23
Issue number: 2
Article number: 50
ISSN (Print): 1610-2940
Ratings: 
  • Scopus rating (2017): CiteScore 2.3 SJR 0.36 SNIP 0.534
Original language: English
ASJC Scopus subject areas: Catalysis, Computer Science Applications, Physical and Theoretical Chemistry, Organic Chemistry, Computational Theory and Mathematics, Inorganic Chemistry
Keywords: Basis set, Benchmarking, Density functional theory, Halogen bonding
Source: Scopus
Source ID: 85011684872

Research output: Contribution to journalArticleScientificpeer-review

Biological removal of selenate and ammonium by activated sludge in a sequencing batch reactor

Wastewaters contaminated by both selenium and ammonium need to be treated prior to discharge into natural water bodies, but there are no studies on the simultaneous removal of selenium and ammonium. A sequencing batch reactor (SBR) was inoculated with activated sludge and operated for 90 days. The highest ammonium removal efficiency achieved was 98%, while the total nitrogen removal was 75%. Nearly a complete chemical oxygen demand removal efficiency was attained after 16 days of operation, whereas complete selenate removal was achieved only after 66 days. The highest total Se removal efficiency was 97%. Batch experiments showed that the total Se in the aqueous phase decreased by 21% with increasing initial ammonium concentration from 50 to 100 mg L−1. This study showed that SBR can remove both selenate and ammonium via, respectively, bioreduction and partial nitrification-denitrification and thus offer possibilities for treating selenium and ammonium contaminated effluents.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Industrial Bioengineering and Applied Organic Chemistry, UPEM, Homi Bhabha National Institute, Mumbai, Hydraulic and Environmental Engineering (IHE) Inst. for Water Education
Contributors: Mal, J., Nancharaiah, Y. V., van Hullebusch, E. D., Lens, P. N.
Number of pages: 9
Pages: 11-19
Publication date: 2017
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 229
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2017): CiteScore 10 SJR 2.029 SNIP 1.84
Original language: English
ASJC Scopus subject areas: Bioengineering, Environmental Engineering, Waste Management and Disposal
Keywords: Activated sludge, Elemental selenium, Selenate bioreduction, Sequencing batch reactor, Simultaneous nitrification and denitrification
Source: Scopus
Source ID: 85009200824

Research output: Contribution to journalArticleScientificpeer-review

Aligned Poly(ε-caprolactone) Nanofibers Guide the Orientation and Migration of Human Pluripotent Stem Cell-Derived Neurons, Astrocytes, and Oligodendrocyte Precursor Cells In Vitro

Stem cell transplantations for spinal cord injury (SCI) have been studied extensively for the past decade in order to replace the damaged tissue with human pluripotent stem cell (hPSC)-derived neural cells. Transplanted cells may, however, benefit from supporting and guiding structures or scaffolds in order to remain viable and integrate into the host tissue. Biomaterials can be used as supporting scaffolds, as they mimic the characteristics of the natural cellular environment. In this study, hPSC-derived neurons, astrocytes, and oligodendrocyte precursor cells (OPCs) are cultured on aligned poly(ε-caprolactone) nanofiber platforms, which guide cell orientation to resemble that of spinal cord in vivo. All cell types are shown to efficiently spread over the nanofiber platform and orient according to the fiber alignment. Human neurons and astrocytes require extracellular matrix molecule coating for the nanofibers, but OPCs grow on nanofibers without additional treatment. Furthermore, the nanofiber platform is combined with a 3D hydrogel scaffold with controlled thickness, and nanofiber-mediated orientation of hPSC-derived neurons is also demonstrated in a 3D environment. In this work, clinically relevant materials and substrates for nanofibers, fiber coatings, and hydrogel scaffolds are used and combined with cells suitable for developing functional cell grafts for SCI repair.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science, Research group: Materials Characterization
Contributors: Hyysalo, A., Ristola, M., Joki, T., Honkanen, M., Vippola, M., Narkilahti, S.
Publication date: 2017
Peer-reviewed: Yes
Early online date: 2017

Publication information

Journal: MACROMOLECULAR BIOSCIENCE
Volume: 17
Issue number: 7
Article number: 1600517
ISSN (Print): 1616-5187
Ratings: 
  • Scopus rating (2017): CiteScore 5.7 SJR 1.017 SNIP 0.776
Original language: English
ASJC Scopus subject areas: Biotechnology, Bioengineering, Biomaterials, Polymers and Plastics, Materials Chemistry
Keywords: 3D environment, Differentiated neural cell, Human pluripotent stem cell, Nanofiber, Orientation
Source: Scopus
Source ID: 85017192272

Research output: Contribution to journalArticleScientificpeer-review

Two cations, two mechanisms: Interactions of sodium and calcium with zwitterionic lipid membranes

Adsorption of metal cations onto a cellular membrane changes its properties, such as interactions with charged moieties or the propensity for membrane fusion. It is, however, unclear whether cells can regulate ion adsorption and the related functions via locally adjusting their membrane composition. We employed fluorescence techniques and computer simulations to determine how the presence of cholesterol - a key molecule inducing membrane heterogeneity - affects the adsorption of sodium and calcium onto zwitterionic phosphatidylcholine bilayers. We found that the transient adsorption of sodium is dependent on the number of phosphatidylcholine head groups, while the strong surface binding of calcium is determined by the available surface area of the membrane. Cholesterol thus does not affect sodium adsorption and only plays an indirect role in modulating the adsorption of calcium by increasing the total surface area of the membrane. These observations also indicate how lateral lipid heterogeneity can regulate various ion-induced processes including adsorption of peripheral proteins, nanoparticles, and other molecules onto membranes.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, University of Helsinki, J. Heyrovský Institute of Physical Chemistry, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic
Contributors: Javanainen, M., Melcrová, A., Magarkar, A., Jurkiewicz, P., Hof, M., Jungwirth, P., Martinez-Seara, H.
Number of pages: 4
Pages: 5380-5383
Publication date: 2017
Peer-reviewed: Yes

Publication information

Journal: Chemical Communications
Volume: 53
Issue number: 39
ISSN (Print): 1359-7345
Ratings: 
  • Scopus rating (2017): CiteScore 11.9 SJR 2.555 SNIP 1.127
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
Electronic versions: 
Source: Scopus
Source ID: 85021689400

Research output: Contribution to journalArticleScientificpeer-review

Supramolecular control of liquid crystals by doping with halogen-bonding dyes

Introducing photochromic or polymeric dopants into nematic liquid crystals is a well-established method to create stimuli-responsive photonic materials with the ability to "control light with light". Herein, we demonstrate a new material design concept by showing that specific supramolecular interactions between the host liquid crystal and the guest dopants enhance the optical performance of the doped liquid crystals. By varying the type and strength of the dopant-host interaction, the phase-transition temperature, the order parameter of the guest molecules, and the diffraction signal in response to interference irradiation, can be accurately engineered. Our concept points out the potential of supramolecular interactions in liquid-crystal photonics, being valuable for optimizing the design of dye-doped functional liquid-crystalline systems.

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, Département de Chimie, Succ. Centre-Ville, Politecnico di Milano, Università degli Studi di Milano, Tokyo Institute of Technology, VTT Technical Research Centre of Finland
Contributors: Vapaavuori, J., Siiskonen, A., Dichiarante, V., Forni, A., Saccone, M., Pilati, T., Pellerin, C., Shishido, A., Metrangolo, P., Priimagi, A.
Number of pages: 6
Pages: 40237-40242
Publication date: 2017
Peer-reviewed: Yes

Publication information

Journal: RSC Advances
Volume: 7
Issue number: 64
ISSN (Print): 2046-2069
Ratings: 
  • Scopus rating (2017): CiteScore 5.5 SJR 0.863 SNIP 0.736
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all)
Electronic versions: 
Source: Scopus
Source ID: 85028088976

Research output: Contribution to journalArticleScientificpeer-review

Cultivation of Scenedesmus acuminatus in different liquid digestates from anaerobic digestion of pulp and paper industry biosludge

Different undiluted liquid digestates from mesophilic and thermophilic anaerobic digesters of pulp and paper industry biosludge with and without thermal pretreatment were characterized and utilized for cultivating Scenedesmus acuminatus. Higher S. acuminatus biomass yields were obtained in thermophilic digestates (without and with pretreatment prior to anaerobic digestion (AD): 10.2 ± 2.2 and 10.8 ± 1.2 g L−1, respectively) than in pretreated mesophilic digestates (7.8 ± 0.3 g L−1), likely due to differences in concentration of sulfate, iron, and/or other minor nutrients. S. acuminatus removed over 97.4% of ammonium and 99.9% of phosphate and sulfate from the digestates. Color (74–80%) and soluble COD (29–39%) of the digestates were partially removed. Different AD processes resulted in different methane yields (18–126 L CH4 kg−1 VS), digestate compositions, and microalgal yields. These findings emphasize the importance of optimizing each processing step in wood-based biorefineries and provide information for pulp and paper industry development for enhancing value generation.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy
Contributors: Tao, R., Lakaniemi, A., Rintala, J. A.
Number of pages: 8
Pages: 706-713
Publication date: 2017
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 245
Issue number: A
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2017): CiteScore 10 SJR 2.029 SNIP 1.84
Original language: English
ASJC Scopus subject areas: Bioengineering, Environmental Engineering, Renewable Energy, Sustainability and the Environment, Waste Management and Disposal
Keywords: Digestate characteristics, Microalgal growth, Nutrient recovery, Pulp and paper industry, Wastewater treatment
Source: Scopus
Source ID: 85029373417

Research output: Contribution to journalArticleScientificpeer-review

Dynamic response to process disturbances—A comparison between TMB/SMB models in transient regime

The modelling and design of Simulated moving bed (SMB) processes is normally done using the True moving bed (TMB) approximation. Several studies show that average values obtained at cyclic steady state for SMB units approach the TMB unit at steady state and that this approach is better as the number of columns in the SMB increases. However, studies that evaluate this equivalence under dynamic conditions are scarce. The objective of this work is to perform an analysis of the transient behaviour of two SMB units, with four and eight columns, and compare the results with the ones obtained for a TMB unit. An analysis of the impact of operating variables on the processes performance parameters is performed. The results show that TMB/SMB equivalence is valid only for conditions that do not violate the regeneration/separation regions and that the transient behaviour of the four columns SMB can resemble more the TMB.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Univ Porto, Universidade do Porto, Fac Med, Dept Med Imaging
Contributors: Nogueira, I. B., Ribeiro, A. M., Rodrigues, A. E., Loureiro, J. M.
Number of pages: 15
Pages: 230-244
Publication date: 2017
Peer-reviewed: Yes

Publication information

Journal: Computers and Chemical Engineering
Volume: 99
ISSN (Print): 0098-1354
Ratings: 
  • Scopus rating (2017): CiteScore 6.1 SJR 1.024 SNIP 1.639
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Computer Science Applications
Keywords: Dynamic behaviour, Enantiomers separation, Simulated moving bed, True moving bed
Source: Scopus
Source ID: 85012284107

Research output: Contribution to journalArticleScientificpeer-review

Particle emissions characterization from a medium-speed marine diesel engine with two fuels at different sampling conditions

Particle emission characteristics for a medium-speed four-stroke marine diesel engine were studied using a variety of sampling systems. Measurements were conducted at 25% and 75% load employing a heavy fuel oil (HFO) and a lighter marine distillate oil. The measurements, especially with HFO, revealed that marine exhaust particles mostly consist of nanometer sized ash particles on which heavy volatile species condense during exhaust dilution and cooling. The soot mode number concentration was low with both fuels tested, in particular when HFO was used. Total particle number emissions ranged in the order of 5.2–6.9 × 1015 per kg of fuel and formed a monomodal size distribution when a porous tube diluter combined with an ageing chamber and operating at low dilution ratio was used for sampling. The levels and size distributions obtained in the lab using a porous tube diluter were similar to the ones reported in the literature studying ship plumes following atmospheric dilution. Lab measurements with ejector-type diluters mostly led to bi-modal distributions that did not well resemble atmospheric size distributions. Moreover, the nucleation mode formed with the ejector diluters was variable in size and concentration. When used with dilution air at ambient temperature, ejector diluters were inappropriate for primary dilution due to clogging.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Physics, Aerosol Physics Laboratory, VTT Technical Research Centre of Finland, Finnish Meteorological Institute
Contributors: Ntziachristos, L., Saukko, E., Lehtoranta, K., Rönkkö, T., Timonen, H., Simonen, P., Karjalainen, P., Keskinen, J.
Number of pages: 10
Pages: 456-465
Publication date: 15 Dec 2016
Peer-reviewed: Yes

Publication information

Journal: Fuel
Volume: 186
ISSN (Print): 0016-2361
Ratings: 
  • Scopus rating (2016): CiteScore 7.8 SJR 1.736 SNIP 2.206
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Fuel Technology, Energy Engineering and Power Technology, Organic Chemistry
Keywords: Heavy fuel oil, Light fuel oil, Marine emissions, Particle emissions, Soot particles
Source: Scopus
Source ID: 84984817885

Research output: Contribution to journalArticleScientificpeer-review

The effect of low-temperature pretreatment on the solubilization and biomethane potential of microalgae biomass grown in synthetic and wastewater media

Microalgae have been suggested as a sustainable raw material for biofuel production in the form of methane via anaerobic digestion. Here, pretreatments at 60–80 °C were investigated, aiming to study the impact of algae culture media on biomethane potential and pretreatment efficiency. Chlorella vulgaris and mixed culture of native algae species (dominating by Scenedesmus sp.) were grown in synthetic medium, wastewater (sterilized and non-sterilized) and digestate from anaerobic digestion of pulp and paper biosludge (sterilized and non-sterilized). The biomethane potential for native microalgal biomass varied between 154 and 252 L CH4 kg−1 VS depending on culture media. The efficiency of the low-temperature pretreatment (80 °C, 3 h) for solubilization (9–12%) of C. vulgaris and native algae biomass was similar for algae grown in sterilized and non-sterilized wastewater media. The pretreatment increased the biomethane potential of native algae biomass by 11–24%.

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: Kinnunen, V., Rintala, J.
Number of pages: 7
Pages: 78-84
Publication date: 1 Dec 2016
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 221
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2016): CiteScore 9.9 SJR 2.215 SNIP 1.945
Original language: English
ASJC Scopus subject areas: Bioengineering, Environmental Engineering, Waste Management and Disposal
Keywords: Anaerobic digestion, Digestate, Microalgae, Pulp and paper industry, Wastewater
Source: Scopus
Source ID: 84988027316

Research output: Contribution to journalArticleScientificpeer-review

Magnesium aminoclay enhances lipid production of mixotrophic Chlorella sp. KR-1 while reducing bacterial populations

Improving lipid productivity and preventing overgrowth of contaminating bacteria are critical issues relevant to the commercialization of the mixotrophic microalgae cultivation process. In this paper, we report the use of magnesium aminoclay (MgAC) nanoparticles for enhanced lipid production from oleaginous Chlorella sp. KR-1 with simultaneous control of KR-1-associated bacterial growth in mixotrophic cultures with glucose as the model substrate. Addition of 0.01–0.1 g/L MgAC promoted microalgal biomass production better than the MgAC-less control, via differential biocidal effects on microalgal and bacterial cells (the latter being more sensitive to MgAC's bio-toxicity than the former). The inhibition effect of MgAC on co-existing bacteria was, as based on density-gradient-gel-electrophoresis (DGGE) analysis, largely dosage-dependent and species-specific. MgAC also, by inducing an oxidative stress environment, increased both the cell size and lipid content of KR-1, resulting in a considerable, ∼25% improvement of mixotrophic algal lipid productivity (to ∼410 mg FAME/L/d) compared with the untreated control.

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, Chungnam National University, Korea Institute of Energy Research, Gachon University
Contributors: Kim, B., Praveenkumar, R., Lee, J., Nam, B., Kim, D. M., Lee, K., Lee, Y. C., Oh, Y. K.
Number of pages: 6
Pages: 608-613
Publication date: 1 Nov 2016
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 219
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2016): CiteScore 9.9 SJR 2.215 SNIP 1.945
Original language: English
ASJC Scopus subject areas: Bioengineering, Environmental Engineering, Waste Management and Disposal
Keywords: Aminoclay, Bacteria, Chlorella, Lipid, Mixotrophic culture
Source: Scopus
Source ID: 84982219447

Research output: Contribution to journalArticleScientificpeer-review

Mild pressure induces rapid accumulation of neutral lipid (triacylglycerol) in Chlorella spp.

Effective enhancement of neutral lipid (especially triacylglycerol, TAG) content in microalgae is an important issue for commercialization of microalgal biorefineries. Pressure is a key physical factor affecting the morphological, physiological, and biochemical behaviors of organisms. In this paper, we report a new stress-based method for induction of TAG accumulation in microalgae (specifically, Chlorella sp. KR-1 and Ch. sp. AG20150) by very-short-duration application of mild pressure. Pressure treatments of 10–15 bar for 2 h resulted in a considerable, ∼55% improvement of the 10–100 g/L cells’ TAG contents compared with the untreated control. The post-pressure-treatment increase of cytoplasmic TAG granules was further confirmed by transmission electron microscopy (TEM). Notwithstanding the increased TAG content, the total lipid content was not changed by pressurization, implying that pressure stress possibly induces rapid remodeling/transformation of algal lipids rather than de novo biosynthesis of TAG.

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, Chungnam National University, Korea Institute of Energy Research
Contributors: Ramasamy, P., Kim, B., Lee, J., Vijayan, D., Lee, K., Nam, B., Jeon, S. G., Kim, D. M., Oh, Y. K.
Number of pages: 5
Pages: 661-665
Publication date: 1 Nov 2016
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 220
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2016): CiteScore 9.9 SJR 2.215 SNIP 1.945
Original language: English
ASJC Scopus subject areas: Bioengineering, Environmental Engineering, Waste Management and Disposal
Keywords: Induction, Microalgae, Neutral lipid, Pressure stress, Triacylglycerol
Source: Scopus
Source ID: 84989931657

Research output: Contribution to journalArticleScientificpeer-review

Grain orientation dependent Nb-Ti microalloying mediated surface segregation on ferritic stainless steel

Surface segregation and oxide formation anisotropy on Ti-Nb stabilized ferritic stainless steel (EN 1.4521) were studied by XPS and Electron Backscatter Diffraction. Competitive surface segregation of Si, Nb and Ti was initiated at ∼550. °C, and segregation was favored to the open surface sites of 〈111〉 oriented grains. Furthermore, the surface segregation of Cr was strongly limited at the locations of stable Ti(CN)- and (NbTi)C-type precipitates. Consequently, the oxidation resistance of stainless steels can be enhanced cost-efficiently, without alloy additions, by optimizing the microstructure to facilitate the fast and uniform growth of protective oxide scale.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Optoelectronics Research Centre, Research group: Surface Science, Department of Materials Science, Research group: Materials Characterization
Contributors: Ali-Löytty, H., Hannula, M., Honkanen, M., Östman, K., Lahtonen, K., Valden, M.
Pages: 204-213
Publication date: Nov 2016
Peer-reviewed: Yes

Publication information

Journal: Corrosion Science
Volume: 112
ISSN (Print): 0010-938X
Ratings: 
  • Scopus rating (2016): CiteScore 9.6 SJR 1.891 SNIP 2.467
Original language: English
ASJC Scopus subject areas: Materials Science(all), Chemical Engineering(all), Chemistry(all)
Keywords: A. Stainless steel, B. SEM, B. XPS, C. Interfaces, C. Oxidation, C. Segregation
Source: Scopus
Source ID: 84979753478

Research output: Contribution to journalArticleScientificpeer-review

Increased survival rate by local release of diclofenac in a murine model of recurrent oral carcinoma

Despite aggressive treatment with radiation and combination chemotherapy following tumor resection, the 5-year survival rate for patients with head and neck cancer is at best only 50%. In this study, we examined the therapeutic potential of localized release of diclofenac from electrospun nanofibers generated from poly(d,l-lactide-co-glycolide) polymer. Diclofenac was chosen since anti-inflammatory agents that inhibit cyclooxygenase have shown great potential in their ability to directly inhibit tumor growth as well as suppress inflammation-mediated tumor growth. A mouse resection model of oral carcinoma was developed by establishing tumor growth in the oral cavity by ultrasound-guided injection of 1 million SCC-9 cells in the floor of the mouth. Following resection, mice were allocated into four groups with the following treatment: 1) no treatment, 2) implanted scaffolds without diclofenac, 3) implanted scaffolds loaded with diclofenac, and 4) diclofenac given orally. Small animal ultrasound and magnetic resonance imaging were utilized for longitudinal determination of tumor recurrence. At the end of 7 weeks following tumor resection, 33% of mice with diclofenac-loaded scaffolds had a recurrent tumor, in comparison to 90%-100% of the mice in the other three groups. At this time point, mice with diclofenac-releasing scaffolds showed 89% survival rate, while the other groups showed survival rates of 10%-25%. Immunohistochemical staining of recurrent tumors revealed a near 10-fold decrease in the proliferation marker Ki-67 in the tumors derived from mice with diclofenac-releasing scaffolds. In summary, the local application of diclofenac in an orthotopic mouse tumor resection model of oral cancer reduced tumor recurrence with significant improvement in survival over a 7-week study period following tumor resection. Local drug release of anti-inflammatory agents should be investigated as a therapeutic option in the prevention of tumor recurrence in oral squamous carcinoma.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Electronics and Communications Engineering, Clinic for Radiology and Neuroradiology, University Hospital Schleswig-Holstein, Institute of Biochemistry, University Hospital Cologne
Contributors: Will, O. M., Purcz, N., Chalaris, A., Heneweer, C., Boretius, S., Purcz, L., Nikkola, L., Ashammakhi, N., Kalthoff, H., Glüer, C. C., Wiltfang, J., Açil, Y., Tiwari, S.
Number of pages: 11
Pages: 5311-5321
Publication date: 12 Oct 2016
Peer-reviewed: Yes

Publication information

Journal: International Journal of Nanomedicine
Volume: 11
ISSN (Print): 1176-9114
Ratings: 
  • Scopus rating (2016): CiteScore 7 SJR 1.174 SNIP 1.211
Original language: English
ASJC Scopus subject areas: Bioengineering, Biophysics, Biomaterials, Drug Discovery, Organic Chemistry
Keywords: Drug releasing polymers, Head and neck cancer, Mouse model, NSAIDs, Oral squamous cell carcinoma, Tumor recurrence
Source: Scopus
Source ID: 84991726470

Research output: Contribution to journalArticleScientificpeer-review

Elimination of arsenic-containing emissions from gasification of chromated copper arsenate wood

The behavior of arsenic in chromated copper arsenate containing wood during gasification was modeled using thermodynamic equilibrium calculations. The results of the model were validated using bench-scale gasification tests. It is shown that over 99.6% of arsenic can be removed from the product gas by a hot filter when the gas is cooled below the predicted condensation temperature.

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, Energy Technology and Thermal Process Chemistry, Gasification Technologies Inc., Gas Technology Institute
Contributors: Kramb, J., Konttinen, J., Backman, R., Salo, K., Roberts, M.
Number of pages: 6
Pages: 319-324
Publication date: 1 Oct 2016
Peer-reviewed: Yes

Publication information

Journal: Fuel
Volume: 181
ISSN (Print): 0016-2361
Ratings: 
  • Scopus rating (2016): CiteScore 7.8 SJR 1.736 SNIP 2.206
Original language: English
ASJC Scopus subject areas: Fuel Technology, Energy Engineering and Power Technology, Chemical Engineering(all), Organic Chemistry
Keywords: Arsenic, CCA wood, Equilibrium modeling, Gasification
Source: Scopus
Source ID: 84965081806

Research output: Contribution to journalArticleScientificpeer-review

Long-term stability of bioelectricity generation coupled with tetrathionate disproportionation

To prevent uncontrolled acidification of the environment, reduced inorganic sulfur compounds (RISCs) can be bioelectrochemically removed from water streams. The long-term stability of bioelectricity production from tetrathionate (S4O6 2-) was studied in highly acidic conditions (pH <2.5) in two-chamber fed-batch microbial fuel cells (MFCs). The maximum current density was improved from previously reported 80 mA m-2 to 225 mA m-2 by optimizing the external resistance. The observed reaction products of tetrathionate disproportionation were sulfate and elemental sulfur. In long-term run, stable electricity production was obtained for over 700 days with the average current density of 150 mA m-2. The internal resistance of the MFC decreased over time and no biofouling was observed. This study shows that tetrathionate is an efficient substrate also for long-term bioelectricity production.

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: Sulonen, M. L. K., Lakaniemi, A. M., Kokko, M. E., Puhakka, J. A.
Number of pages: 7
Pages: 876-882
Publication date: 1 Sep 2016
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 216
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2016): CiteScore 9.9 SJR 2.215 SNIP 1.945
Original language: English
ASJC Scopus subject areas: Bioengineering, Environmental Engineering, Waste Management and Disposal
Keywords: Acidophile, Disproportionation, Long-term stability, Microbial fuel cell, Tetrathionate
Source: Scopus
Source ID: 84974777755

Research output: Contribution to journalArticleScientificpeer-review

3D micro-nano structured hybrid scaffolds: An investigation into the role of nanofiber coating on viability, proliferation and differentiation of seeded mesenchymal stem cells

The introduction of a three dimensional scaffold providing the closest analogies to extracellular matrix (ECM) is currently a key strategy for tackling many challenges in tissue repair. Here, we present a new hybrid scaffold constructed by coating electrospun chitosan/polyethylene oxide (PEO) nanofibers on commercial BioTek polystyrene (PS) scaffold obtained from Sigma Aldrich. The viability and proliferation rate of mesenchymal stem cells (MSCs) seeded on micro-nano structured hybrid scaffold (MNHS) and commercial PS scaffolds were analyzed by MTT assay. The results of the MTT assay revealed a higher degree of viability and proliferation rate in MSCs seeded on MNHS compared with the commercial PS scaffold. DAPI images also confirmed the higher degree of attachment and viability of MSCs seeded on MNHS. Moreover, MSCs on both scaffolds differentiated to osteoblasts and adipocytes cells, as reflected by the images obtained from Alizarin Red and Oil Red-O staining. Alkaline phosphatase activity (ALP) and calcium content assays revealed that the MNHS has a higher potential for osteogenic differentiation than the commercial scaffold. To quantify the osteoblast and adipocyte gene expression, quantitative RT-PCR was carried out for MNHS, commercial scaffold and Tissue culture polystyrene (TCPS). It was found that MNHS can express a higher level of Runt-related transcription factor 2 (Runx2), osteonectin and osteocalcin in osteogenic differentiation as well as increased expression of PPARγ and UCP-1 in adipogenic differentiation. The enhancement of the attachment, viability and proliferation as well as bi-lineage differentiation may result from the biochemical and structural analogies of MNHS to native ECM. Furthermore, it was observed that biocompatible MNHS scaffold can potentially be utilized as a suitable scaffold for bone and connective tissue engineering.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Materials Science, Research group: Fibre Materials, Tarbiat Modares University, Isfahan University of Medical Sciences, VTT Technical Research Centre of Finland
Contributors: Pilehrood, M. K., Atashi, A., Sadeghi-Aliabadi, H., Nousiainen, P., Harlin, A.
Number of pages: 8
Pages: 9000-9007
Publication date: 1 Sep 2016
Peer-reviewed: Yes

Publication information

Journal: Journal Nanoscience and Nanotechnology
Volume: 16
Issue number: 9
ISSN (Print): 1533-4880
Ratings: 
  • Scopus rating (2016): CiteScore 2.3 SJR 0.324 SNIP 0.486
Original language: English
ASJC Scopus subject areas: Bioengineering, Chemistry(all), Biomedical Engineering, Materials Science(all), Condensed Matter Physics
Keywords: Adipogenic Differentiation, Hybrid Scaffold, Mesenchymal Stem Cell, Micro Porosity, Nanofiber, Osteogenic Differentiation

Bibliographical note

EXT="Harlin, Ali"

Source: Scopus
Source ID: 84983416664

Research output: Contribution to journalArticleScientificpeer-review

Modeling of the catalytic effects of potassium and calcium on spruce wood gasification in CO2

Using previously reported thermogravimetric analysis measurements, the effects of calcium and potassium on the char gasification rate of spruce wood were modeled. Spruce wood was leached of inorganic ash elements and doped with measured amounts of potassium and calcium. The wood was gasified in an isothermal thermogravimetric analysis device in CO2 where the devolatilization of the wood, char formation and char gasification all occurred inside the preheated reactor. A new method for separating the effects of devolatilization and char gasification is presented. Kinetic models were evaluated for their ability to describe the observed catalytic effects of potassium and calcium on the gasification rate. Two modified versions of the random pore model were able to accurately describe the measured conversion rates and the parameters of the kinetic models were found to be dependent on the calcium and potassium concentrations. Empirical correlations were developed to predict the char conversion rate from only the potassium and calcium concentration of the sample.

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, Johan Gadolin Process Chemistry Centre, Abo Akademi University, VTT Technical Research Centre of Finland
Contributors: Kramb, J., DeMartini, N., Perander, M., Moilanen, A., Konttinen, J.
Number of pages: 10
Pages: 50-59
Publication date: 1 Jul 2016
Peer-reviewed: Yes

Publication information

Journal: Fuel Processing Technology
Volume: 148
ISSN (Print): 0378-3820
Ratings: 
  • Scopus rating (2016): CiteScore 6.8 SJR 1.397 SNIP 1.769
Original language: English
ASJC Scopus subject areas: Fuel Technology, Energy Engineering and Power Technology, Chemical Engineering(all)
Keywords: Biomass, Gasification, Modeling, Reaction kinetics

Bibliographical note

EXT=”Moilanen, Antero"

Source: Scopus
Source ID: 84959431503

Research output: Contribution to journalArticleScientificpeer-review

Hydrothermal carbonization of pulp mill streams

The progress of the conversion, the yield, the structure and the morphology of the produced carbonaceous materials as a function of time were systematically studied with pyrolysis-GC/FID and FESEM microscope. The conversion of galactoglucomannan, bleached kraft pulp and TEMPO oxidized cellulose nanofibrils followed the reaction route of glucose being slower though with fibrous material, higher molar mass and viscosity. The conversion of kraft lignin was minor following completely different reaction route. Carbonaceous particles of different shape and size were produced with yields between 23% and 73% after 4 h with being higher for lignin than carbohydrates. According to the results, potential pulp mill streams represent lignocellulosic resources for generation of carbonaceous materials.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Materials Science, Research group: Materials Characterization, VTT Technical Research Centre of Finland
Contributors: Wikberg, H., Ohra-aho, T., Honkanen, M., Kanerva, H., Harlin, A., Vippola, M., Laine, C.
Number of pages: 9
Pages: 236-244
Publication date: 1 Jul 2016
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 212
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2016): CiteScore 9.9 SJR 2.215 SNIP 1.945
Original language: English
ASJC Scopus subject areas: Bioengineering, Environmental Engineering, Waste Management and Disposal
Keywords: Galactoglucomannan, Hydrothermal carbonization, Kraft lignin, Kraft pulp, Pulp mill

Bibliographical note

EXT="Harlin, Ali"

Source: Scopus
Source ID: 84963954557

Research output: Contribution to journalArticleScientificpeer-review

The influence of high-temperature sulfuric acid solution ageing on the properties of laminated vinyl-ester joints

A carbon fiber powder doped corrosion layer is used as an inner layer in large composite tanks to improve their chemical and wear resistance. In joints fabricated on site, this layer is embedded into the structure. This study evaluates the lap shear strength of specimens, simulating a laminated joint in between the corrosion layer and the inner joint laminate. Lap-shear tests were carried out for as-fabricated and aged laminates at room temperature and at elevated temperature. Ageing was carried out for half a year in a 95 °C pressurized sulfuric acid solution. The tests showed that, after ageing, the room temperature shear strength remained unaltered but high-temperature shear strength was lowered. When the temperature increased, the failure location shifted from the interface between the doped layer and the joint laminate to the doped layer. Thermal analysis and microscopy were employed to clarify the reasons for the observed behavior.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Materials Science, Research group: Plastics and Elastomer Technology, Outotec Research Center, Aalto University
Contributors: Lindgren, M., Wallin, M., Kakkonen, M., Saarela, O., Vuorinen, J.
Number of pages: 7
Pages: 298-304
Publication date: 1 Jul 2016
Peer-reviewed: Yes

Publication information

Journal: International Journal of Adhesion and Adhesives
Volume: 68
ISSN (Print): 0143-7496
Ratings: 
  • Scopus rating (2016): CiteScore 4 SJR 0.919 SNIP 1.516
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Biomaterials, Polymers and Plastics
Keywords: Aging, Lap-shear, Sulfuric acid, Vinyl ester

Bibliographical note

EXT="Lindgren, M."

Source: Scopus
Source ID: 84973340146

Research output: Contribution to journalArticleScientificpeer-review

Spontaneous formation of three-dimensionally ordered Bi-rich nanostructures within GaAs1-xBix/GaAs quantum wells

In this work, we report on the spontaneous formation of ordered arrays of nanometer-sized Bi-rich structures due to lateral composition modulations in Ga(As,Bi)/GaAs quantum wells grown by molecular beam epitaxy. The overall microstructure and chemical distribution is investigated using transmission electron microscopy. The information is complemented by synchrotron x-ray grazing incidence diffraction, which provides insight into the in-plane arrangement. Due to the vertical inheritance of the lateral modulation, the Bi-rich nanostructures eventually shape into a three-dimensional assembly. Whereas the Bi-rich nanostructures are created via two-dimensional phase separation at the growing surface, our results suggest that the process is assisted by Bi segregation which is demonstrated to be strong and more complex than expected, implying both lateral and vertical (surface segregation) mass transport. As demonstrated here, the inherent thermodynamic miscibility gap of Ga(As,Bi) alloys can be exploited to create highly uniform Bi-rich units embedded in a quantum confinement structure.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Optoelectronics Research Centre, Research group: Semiconductor Technology and Applications, Hausvogteiplatz 5-7
Contributors: Luna, E., Wu, M., Hanke, M., Puustinen, J., Guina, M., Trampert, A.
Publication date: 1 Jul 2016
Peer-reviewed: Yes

Publication information

Journal: Nanotechnology
Volume: 27
Issue number: 32
Article number: 325603
ISSN (Print): 0957-4484
Ratings: 
  • Scopus rating (2016): CiteScore 5.8 SJR 1.339 SNIP 0.982
Original language: English
ASJC Scopus subject areas: Bioengineering, Chemistry(all), Electrical and Electronic Engineering, Mechanical Engineering, Mechanics of Materials, Materials Science(all)
Keywords: GaAsBi, phase separation and segregation, self organization, TEM

Bibliographical note

EXT="Wu, M."

Source: Scopus
Source ID: 84978884196

Research output: Contribution to journalArticleScientificpeer-review

The Influence of Phosphorus Exposure on a Natural-Gas-Oxidation Catalyst

Phosphorus is found to have a deactivating effect on the catalytic activity of the studied natural-gas-oxidation catalyst. Accelerated laboratory-scale phosphorus treatment was done to the PtPd/Al2O3 natural gas oxidation catalyst. The effect of phosphorus after low (0.065 M) and high (0.13 M) phosphorus concentration treatments was studied by using an inductively coupled plasma optical emission spectroscopy, N2 physisorption, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. In addition, the behavior of the catalyst was studied by a Gasmet FT-IR gas analyzer. Based on the received results it can be concluded that phosphorus was adsorbed on the surface by chemical bonds forming phosphates (PO4). In addition, the partial transformation of PdO to Pd was observed. Due to the phosphorus adsorption both the CO and CH4 oxidation activities were lower after the phosphorus treatments compared with the fresh catalyst.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Materials Science, Research group: Materials Characterization, University of Oulu, Aalto University, Dinex Ecocat Oy, COMP Centre of Excellence, Department of Applied Physics, Aalto University
Contributors: Kärkkäinen, M., Kolli, T., Honkanen, M., Heikkinen, O., Väliheikki, A., Huuhtanen, M., Kallinen, K., Lahtinen, J., Vippola, M., Keiski, R. L.
Number of pages: 5
Pages: 1044-1048
Publication date: 1 Jul 2016
Peer-reviewed: Yes

Publication information

Journal: Topics in Catalysis
Volume: 59
Issue number: 10-12
ISSN (Print): 1022-5528
Ratings: 
  • Scopus rating (2016): CiteScore 4.3 SJR 0.975 SNIP 0.855
Original language: English
ASJC Scopus subject areas: Catalysis, Chemistry(all)
Keywords: Methane degradation, Palladium, Platinum, Poisoning
Source: Scopus
Source ID: 84977071141

Research output: Contribution to journalArticleScientificpeer-review

Development of Magnetic Losses During Accelerated Corrosion Tests for Nd-Fe-B Magnets Used in Permanent Magnet Generators

Sintered Nd-Fe-B magnets are critical components in permanent magnet wind generators. They are the strongest permanent magnets available and thus enable the construction of light and effective devices, but their stability in corrosive environments is limited. In this work, the formation of corrosion losses in two types of Nd-Fe-B alloys was studied. Magnets were in a magnetized state during the corrosion test, enabling monitoring of the development of losses in magnetic flux along with those in weight. Parallel flux and weight loss measurements conducted during corrosion tests showed that percentage weight losses were lower than the total flux losses. Scanning electron microscope studies of corroded specimens disclosed that the magnets first underwent dissolution of the grain-boundary phase, followed by the detachment and movement of the loosened grains in the magnetic field. The degradation was accelerated by oxidation of the matrix phase, which introduced further damage by volume expansion.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Materials Science, Research group: Materials Characterization, VTT Technical Research Centre of Finland
Contributors: Isotahdon, E., Huttunen-Saarivirta, E., Kuokkala, V.
Number of pages: 10
Pages: 732-741
Publication date: 1 Jun 2016
Peer-reviewed: Yes

Publication information

Journal: Corrosion
Volume: 72
Issue number: 6
ISSN (Print): 0010-9312
Ratings: 
  • Scopus rating (2016): CiteScore 3.5 SJR 1.075 SNIP 1.488
Original language: English
ASJC Scopus subject areas: Materials Science(all), Chemical Engineering(all), Chemistry(all)
Keywords: Corrosion, Corrosion losses, Highly accelerated stress test (HAST test), Improved corrosion resistance sintered Nd-Fe-B magnets, Improved stability sintered Nd-Fe-B magnets, Nd-Fe-B, Permanent magnet, Scanning electron microscopy, Thermal losses, Wind power
Source: Scopus
Source ID: 84973626857

Research output: Contribution to journalArticleScientificpeer-review

Wetting hysteresis induced by temperature changes: Supercooled water on hydrophobic surfaces

The state and stability of supercooled water on (super)hydrophobic surfaces is crucial for low temperature applications and it will affect anti-icing and de-icing properties. Surface characteristics such as topography and chemistry are expected to affect wetting hysteresis during temperature cycling experiments, and also the freezing delay of supercooled water. We utilized stochastically rough wood surfaces that were further modified to render them hydrophobic or superhydrophobic. Liquid flame spraying (LFS) was utilized to create a multi-scale roughness by depositing titanium dioxide nanoparticles. The coating was subsequently made non-polar by applying a thin plasma polymer layer. As flat reference samples modified silica surfaces with similar chemistries were utilized. With these substrates we test the hypothesis that superhydrophobic surfaces also should retard ice formation. Wetting hysteresis was evaluated using contact angle measurements during a freeze-thaw cycle from room temperature to freezing occurrence at -7 °C, and then back to room temperature. Further, the delay in freezing of supercooled water droplets was studied at temperatures of -4 °C and -7 °C. The hysteresis in contact angle observed during a cooling-heating cycle is found to be small on flat hydrophobic surfaces. However, significant changes in contact angles during a cooling-heating cycle are observed on the rough surfaces, with a higher contact angle observed on cooling compared to during the subsequent heating. Condensation and subsequent frost formation at sub-zero temperatures induce the hysteresis. The freezing delay data show that the flat surface is more efficient in enhancing the freezing delay than the rougher surfaces, which can be rationalized considering heterogeneous nucleation theory. Thus, our data suggests that molecular flat surfaces, rather than rough superhydrophobic surfaces, are beneficial for retarding ice formation under conditions that allow condensation and frost formation to occur.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Physics, Research area: Aerosol Physics, Research group: Aerosol Synthesis, KTH Royal Institute of Technology, Surface and Corrosion Science, SP Technical Research Institute of Sweden, Department of Civil and Architectural Engineering, Nanostructure Physics
Contributors: Heydari, G., Sedighi Moghaddam, M., Tuominen, M., Fielden, M., Haapanen, J., Mäkelä, J. M., Claesson, P. M.
Number of pages: 13
Pages: 21-33
Publication date: 15 Apr 2016
Peer-reviewed: Yes

Publication information

Journal: Journal of Colloid and Interface Science
Volume: 468
ISSN (Print): 0021-9797
Ratings: 
  • Scopus rating (2016): CiteScore 7.2 SJR 1.156 SNIP 1.277
Original language: English
ASJC Scopus subject areas: Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Biomaterials, Colloid and Surface Chemistry
Keywords: Contact angle, Hydrophobization, Liquid flame spray (LFS), Morphology, Multi-scale roughness, Plasma polymerization, Supercooled water, Superhydrophobicity, Wetting hysteresis, Wood
Source: Scopus
Source ID: 84955276633

Research output: Contribution to journalArticleScientificpeer-review

Effect of heavy metal co-contaminants on selenite bioreduction by anaerobic granular sludge

This study investigated bioreduction of selenite by anaerobic granular sludge in the presence of heavy metals and analyzed the fate of the bioreduced selenium and the heavy metals. Selenite bioreduction was not significantly inhibited in the presence of Pb(II) and Zn(II). More than 92% of 79 mg/L selenite was removed by bioreduction even in the presence of 150 mg/L of Pb(II) or 400 mg/L of Zn(II). In contrast, only 65-48% selenite was bioreduced in the presence of 150-400 mg/L Cd(II). Formation of elemental selenium or selenide varied with heavy metal type and concentration. Notably, the majority of the bioreduced selenium (70-90% in the presence of Pb and Zn, 50-70% in the presence of Cd) and heavy metals (80-90% of Pb and Zn, 60-80% of Cd) were associated with the granular sludge. The results have implications in the treatment of selenium wastewaters and biogenesis of metal selenides.

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, UPEM, Bhabha Atomic Research Centre, Environmental Engineering and Water Technology Department, UNESCO-IHE Institute for Water Education
Contributors: Mal, J., Nancharaiah, Y. V., van Hullebusch, E. D., Lens, P. N. L.
Number of pages: 8
Pages: 1-8
Publication date: 1 Apr 2016
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 206
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2016): CiteScore 9.9 SJR 2.215 SNIP 1.945
Original language: English
ASJC Scopus subject areas: Bioengineering, Environmental Engineering, Waste Management and Disposal
Keywords: Anaerobic granular sludge, Biosorption, Heavy metal removal, Metal selenide, Selenite bioreduction
Source: Scopus
Source ID: 84961305364

Research output: Contribution to journalArticleScientificpeer-review

Metal chalcogenide quantum dots: Biotechnological synthesis and applications

Metal chalcogenide (metal sulfide, selenide and telluride) quantum dots (QDs) have attracted considerable attention due to their quantum confinement and size-dependent photoemission characteristics. QDs are one of the earliest products of nanotechnology that were commercialized for tracking macromolecules and imaging cells in life sciences. An array of physical, chemical and biological methods have been developed to synthesize different QDs. Biological production of QDs follow green chemistry principles, thereby use of hazardous chemicals, high temperature, high pressure and production of by-products is either minimized or completely avoided. In the past decade, significant progress has been made wherein a diverse range of living organisms, i.e. viruses, bacteria, fungi, microalgae, plants and animals have been explored for synthesis of all three types of metal chalcogenide QDs. However, better understanding of the biological mechanisms that mediate the synthesis of metal chalcogenides and control the growth of QDs is needed for improving their yield and properties as well as addressing issues that arise during scale-up. In this review, we present the current status of the biological synthesis and applications of metal chalcogenide QDs. Where possible, the role of key biological macromolecules in controlled production of the nanomaterials is highlighted, and also technological bottlenecks limiting widespread implementation are discussed. The future directions for advancing biological metal chalcogenide synthesis are presented.

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: Mal, J., Nancharaiah, Y. V., Van Hullebusch, E. D., Lens, P. N. L.
Number of pages: 19
Pages: 41477-41495
Publication date: Apr 2016
Peer-reviewed: Yes

Publication information

Journal: RSC Advances
Volume: 6
Issue number: 47
ISSN (Print): 2046-2069
Ratings: 
  • Scopus rating (2016): CiteScore 4.1 SJR 0.889 SNIP 0.757
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Chemistry(all)
Source: Scopus
Source ID: 84966421058

Research output: Contribution to journalArticleScientificpeer-review

Human Adipose Stem Cells Differentiated on Braided Polylactide Scaffolds is a Potential Approach for Tendon Tissue Engineering

Growing number of musculoskeletal defects increases the demand for engineered tendon. Our aim was to find an efficient strategy to produce tendon-like matrix in vitro. To allow efficient differentiation of human adipose stem cells (hASCs) toward tendon tissue, we tested different medium compositions, biomaterials, and scaffold structures in preliminary tests. This is the first study to report that medium supplementation with 50 ng/mL of growth and differentiation factor-5 (GDF-5) and 280 μM l-ascorbic acid are essential for tenogenic differentiation of hASCs. Tenogenic medium (TM) was shown to significantly enhance tendon-like matrix production of hASCs compared to other tested media groups. Cell adhesion, proliferation, and tenogenic differentiation of hASCs were supported on braided poly(l/d)lactide (PLA) 96l/4d copolymer filament scaffolds in TM condition compared to foamed poly(l-lactide-co-ε-caprolactone) (PLCL) 70L/30CL scaffolds. A uniform cell layer formed on braided PLA 96/4 scaffolds when hASCs were cultured in TM compared to maintenance medium (MM) condition after 14 days of culture. Furthermore, total collagen content and gene expression of tenogenic marker genes were significantly higher in TM condition after 2 weeks of culture. The elastic modulus of PLA 96/4 scaffold was more similar to the elastic modulus reported for native Achilles tendon. Our study showed that the optimized TM is needed for efficient and rapid in vitro tenogenic extracellular matrix production of hASCs. PLA 96/4 scaffolds together with TM significantly stimulated hASCs, thus demonstrating the potential clinical relevance of this novel and emerging approach to tendon injury treatments in the future.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Electronics and Communications Engineering, Research group: Biomaterials and Tissue Engineering Group, BioMediTech, Tampere University Hospital, Univ Helsinki, Helsinki University Central Hospital, University of Helsinki, Cent Hosp, Dept Med, Div Nephrol, University of Twente
Contributors: Vuornos, K., Björninen, M., Talvitie, E., Paakinaho, K., Kellomäki, M., Huhtala, H., Miettinen, S., Seppänen-Kaijansinkko, R., Haimi, S.
Number of pages: 11
Pages: 513-523
Publication date: 1 Mar 2016
Peer-reviewed: Yes

Publication information

Journal: Tissue Engineering Part A
Volume: 22
Issue number: 5-6
ISSN (Print): 1937-3341
Ratings: 
  • Scopus rating (2016): CiteScore 7.7 SJR 1.24 SNIP 0.988
Original language: English
ASJC Scopus subject areas: Bioengineering, Biochemistry, Biomedical Engineering, Biomaterials

Bibliographical note

EXT="Vuornos, Kaisa"

Source: Scopus
Source ID: 84961782193

Research output: Contribution to journalArticleScientificpeer-review

Importance of maintenance data quality in extended warranty simulation

As manufacturing industries are transforming towards service orientation, predicting the costs of product-service systems is becoming essential. Simulation is one possibility for evaluating the costs and risks involved in product-service systems, such as extended warranty agreements. We conducted a case study with a globally operating manufacturer of industrial goods who also provides services for the equipment. We created equipment performance simulation (EPSi) models and a tool, EPSitor, for using the models in predicting extended warranty costs. However, reliable simulation results require good quality maintenance and operation data from existing installations. We discovered that it is difficult to collect the data needed for simulations and there were many challenges with data quality. Quality problems were mainly observed in manually collected data. Insufficient data quality leads to a wider margin of error in the simulation models, which increases business risk. Identifying these challenges is the first step in transforming the data collection routines to support equipment performance simulations. The key to long-term business benefits of simulation is to acknowledge the importance of data quality and to establish efficient data collection routines. Future research should find ways to motivate maintenance technicians to collect good quality data. This would contribute to more accurate cost analysis and thus to better profitability of extended warranty contracts.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Mechanical Engineering and Industrial Systems, Research group: Käyttövarmuuden suunnittelu ja kunnossapito, Research area: Life-cycle Management, Aalto University
Contributors: Mahlamäki, K., Niemi, A., Jokinen, J., Borgman, J.
Number of pages: 8
Pages: 3-10
Publication date: 1 Jan 2016
Peer-reviewed: Yes

Publication information

Journal: International Journal of COMADEM
Volume: 19
Issue number: 1
ISSN (Print): 1363-7681
Ratings: 
  • Scopus rating (2016): CiteScore 0.2 SJR 0.128 SNIP 0.163
Original language: English
ASJC Scopus subject areas: Electrical and Electronic Engineering, Industrial and Manufacturing Engineering, Safety, Risk, Reliability and Quality, Bioengineering, Signal Processing, Strategy and Management
Keywords: Asset management, Data quality, Hitman factors

Bibliographical note

INT=mei,”Jokinen, Juuso”

Source: Scopus
Source ID: 84960940492

Research output: Contribution to journalArticleScientificpeer-review

Accelerated deactivation studies of the natural-gas oxidation catalyst-Verifying the role of sulfur and elevated temperature in catalyst aging

Accelerated deactivation, caused by thermal aging (TA) and/or sulfur+water poisoning (SW), of the PtPd/γ-Al2O3 natural-gas oxidation catalyst was studied. Thermal aging and poisoning treatments were performed separately and with varied combinations and comprehensive characterization of the catalyst was carried out after each step. The fresh catalyst has small, oxidized PtPd particles (<5nm) uniformly distributed in the γ-alumina washcoat. After the SW-treatment, a small amount of bulk aluminum sulfate was observed near the slightly grown noble metal particles. During the thermal aging, γ-alumina changed to δ-/θ- and α-alumina. In addition, total decomposition of oxidized Pt and partly decomposition of oxidized Pd occurred resulting in the formation of the grown noble metal particles with a bimetallic PtPd core and a polycrystalline PdO shell. Also few, small (~5nm) bimetallic PtPd particles were still detected. In the TA+SW-treated catalyst with grown noble metal particles, a small amount of bulk aluminum sulfate was detected and it was randomly distributed over the noble metal particles and washcoat. The activity in the terms of methane conversion over the TA-, SW-, and SW+TA-treated catalysts was similar but it was decreased compared to the fresh catalyst. The activity of the TA+SW-treated catalyst was drastically decreased compared to the fresh catalyst due to significant morphological changes and aluminum sulfate formation.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Materials Science, Research group: Materials Characterization, University of Oulu, Aalto University, Chalmers University of Technology, Dinex Ecocat Oy
Contributors: Honkanen, M., Kärkkäinen, M., Kolli, T., Heikkinen, O., Viitanen, V., Zeng, L., Jiang, H., Kallinen, K., Huuhtanen, M., Keiski, R. L., Lahtinen, J., Olsson, E., Vippola, M.
Number of pages: 10
Pages: 439-448
Publication date: 2016
Peer-reviewed: Yes
Early online date: 1 Oct 2015

Publication information

Journal: Applied Catalysis B-Environmental
ISSN (Print): 0926-3373
Ratings: 
  • Scopus rating (2016): CiteScore 14.9 SJR 2.693 SNIP 2.208
Original language: English
ASJC Scopus subject areas: Catalysis, Process Chemistry and Technology, Environmental Science(all)
Keywords: Deactivation, Palladium, Platinum, Sulfur poisoning, Thermal aging
Electronic versions: 
URLs: 
Source: Scopus
Source ID: 84943638016

Research output: Contribution to journalArticleScientificpeer-review

Cell-wall disruption and lipid/astaxanthin extraction from microalgae: Chlorella and Haematococcus

Recently, biofuels and nutraceuticals produced from microalgae have emerged as major interests, resulting in intensive research of the microalgal biorefinery process. In this paper, recent developments in cell-wall disruption and extraction methods are reviewed, focusing on lipid and astaxanthin production from the biotechnologically important microalgae Chlorella and Haematococcus, respectively. As a common, critical bottleneck for recovery of intracellular components such as lipid and astaxanthin from these microalgae, the composition and structure of rigid, thick cell-walls were analyzed. Various chemical, physical, physico-chemical, and biological methods applied for cell-wall breakage and lipid/astaxanthin extraction from Chlorella and Haematococcus are discussed in detail and compared based on efficiency, energy consumption, type and dosage of solvent, biomass concentration and status (wet/dried), toxicity, scalability, and synergistic combinations. This report could serve as a useful guide to the implementation of practical downstream processes for recovery of valuable products from microalgae including Chlorella and Haematococcus.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Korea Institute of Energy Research, KAIST
Contributors: Kim, D. Y., Vijayan, D., Praveenkumar, R., Han, J. I., Lee, K., Park, J. Y., Chang, W. S., Lee, J. S., Oh, Y. K.
Pages: 300-310
Publication date: 2016
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 199
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2016): CiteScore 9.9 SJR 2.215 SNIP 1.945
Original language: English
ASJC Scopus subject areas: Bioengineering, Environmental Engineering, Waste Management and Disposal
Keywords: Astaxanthin, Chlorella, Extraction, Haematococcus, Lipid

Research output: Contribution to journalArticleScientificpeer-review

Remarkable Dependence of the Final Charge Separation Efficiency on the Donor-Acceptor Interaction in Photoinduced Electron Transfer

The unprecedented dependence of final charge separation efficiency as a function of donor-acceptor interaction in covalently-linked molecules with a rectilinear rigid oligo-p-xylene bridge has been observed. Optimization of the donor-acceptor electronic coupling remarkably inhibits the undesirable rapid decay of the singlet charge-separated state to the ground state, yielding the final long-lived, triplet charge-separated state with circa 100% efficiency. This finding is extremely useful for the rational design of artificial photosynthesis and organic photovoltaic cells toward efficient solar energy conversion.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Research group: Supramolecular photochemistry, Kyoto Women's University, Tokushima University, Kobe University, Japan Science and Technology Agency, University of Tokyo
Contributors: Higashino, T., Yamada, T., Yamamoto, M., Furube, A., Tkachenko, N. V., Miura, T., Kobori, Y., Jono, R., Yamashita, K., Imahori, H.
Pages: 629-633
Publication date: 2016
Peer-reviewed: Yes

Publication information

Journal: Angewandte Chemie (International Edition)
Volume: 55
Issue number: 2
ISSN (Print): 1433-7851
Ratings: 
  • Scopus rating (2016): CiteScore 18.7 SJR 5.954 SNIP 2.185
Original language: English
ASJC Scopus subject areas: Chemistry(all), Catalysis
Keywords: Charge separation, Electron transfer, Electronic coupling, Exciplexes, Marcus theory
Source: Scopus
Source ID: 84958749577

Research output: Contribution to journalArticleScientificpeer-review

Preferential adsorption of Cu in a multi-metal mixture onto biogenic elemental selenium nanoparticles

Preferential adsorption of Cu contained in wastewaters is desirable as the Cu can then be reprocessed and reused more easily. In this study, biogenic elemental selenium nanoparticles (BioSeNPs) were assessed for their ability to preferentially adsorb Cu from an equimolar mixture containing Cu, Cd and Zn. Variations in metal to BioSeNPs ratios and initial metal solution pH improved the preferential adsorption capacity of BioSeNPs toward Cu, with the ratio of Cu adsorbed to combined Cd and Zn adsorbed varying from 2.3 to 6.6. More than 78% of the added Cu was adsorbed at an initial metal solution pH of 5.2 and metal to BioSeNPs ratio of 0.21mgmg-1 when the ratio of Cu adsorbed to the sum of Cd and Zn adsorbed was 2.3. Infrared spectroscopy revealed that the Cu, Cd and Zn were interacting with the hydroxyl and carboxyl surface functional groups of the BioSeNPs. The modeling of BioSeNPs' acid-base titration revealed the presence of high concentrations of carboxylic groups (C=60.3molkg-1) with a pKa of 3.9, providing further evidence of their interaction with Cu. The adsorption of Cu resulted in a lower colloidal stability of the BioSeNPs as indicated by more than 99% retention of added BioSeNPs after adsorption of heavy metals and filtration. BioSeNPs showed a good preferential adsorption capacity toward Cu as compared to other adsorbent. This study provides a proof-of-concept for the preferential adsorption of Cu onto BioSeNPs which are present in the effluent of a bioreactor treating selenium oxyanions containing wastewater.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Tampere University of Technology, Research group: Industrial Bioengineering and Applied Organic Chemistry, Université Paris-Est
Contributors: Jain, R., Dominic, D., Jordan, N., Rene, E. R., Weiss, S., van Hullebusch, E. D., Hübner, R., Lens, P. N. L.
Pages: 917–925
Publication date: 2016
Peer-reviewed: Yes
Early online date: 2015

Publication information

Journal: Chemical Engineering Journal
Volume: 284
ISSN (Print): 1385-8947
Ratings: 
  • Scopus rating (2016): CiteScore 9.7 SJR 1.758 SNIP 1.952
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Chemistry(all), Industrial and Manufacturing Engineering, Environmental Chemistry
Keywords: Biogenic, Copper, FT-IR, Heavy metals, Preferential adsorption, Selenium nanoparticles
Source: Scopus
Source ID: 84942540702

Research output: Contribution to journalArticleScientificpeer-review

Composites of high-temperature thermomechanical pulps and polylactic acid

High-temperature thermomechanical pulps (HT-TMP, defibrated at 150 to 170 °C) were compared to a reference TMP (defibrated at 130 °C) as a reinforcement for polylactic acid (PLA). Composites were prepared by melt compounding, followed by injection molding, gradually increasing the used fiber content from 0 to 20 wt.%. The injection-molded specimens were characterized by tensile and impact strength tests, scanning electron microscopy, water absorption tests, and differential scanning calorimetry. The TMP fiber damage was also characterized before and after melt compounding by optical analysis. At 20% fiber content, the Young's modulus increased significantly, while the tensile strength remained unchanged and the impact strength decreased slightly. All fibers suffered damage during melt compounding, but the tensile strength remained about the same as in pure PLA. All types of TMP were able to increase the PLA rate of crystallization. The HT-TMP fibers were dispersed more evenly in PLA than the 130 °C TMP. The 170 °C TMP produced composites of lower water absorption than the other two TMP types, probably because of its lower hemicellulose content and its higher surface coverage by lignin.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Materials Science, Research group: Plastics and Elastomer Technology, Aalto University
Contributors: Solala, I., Koistinen, A., Siljander, S., Vuorinen, J., Vuorinen, T.
Number of pages: 16
Pages: 1125-1140
Publication date: 2016
Peer-reviewed: Yes

Publication information

Journal: BioResources
Volume: 11
Issue number: 1
ISSN (Print): 1930-2126
Ratings: 
  • Scopus rating (2016): CiteScore 2.5 SJR 0.493 SNIP 0.877
Original language: English
ASJC Scopus subject areas: Waste Management and Disposal, Environmental Engineering, Bioengineering
Keywords: High-temperature thermomechanical pulp, Hydrophobic fibers, Mechanical properties, Polylactic acid, Thermal properties, Wood fiber composites
Source: Scopus
Source ID: 84949921508

Research output: Contribution to journalArticleScientificpeer-review

Biological and Bioelectrochemical Recovery of Critical and Scarce Metals

Metal-bearing solid and liquid wastes are increasingly considered as secondary sources of critical and scarce metals. Undoubtedly, microorganisms are a cost-effective resource for extracting and concentrating diffuse elements from secondary sources. Microbial biotechnology for extracting base metals from ores and treatment of metal-laden wastewaters has already been applied at full scale. By contrast, microbe-metal interactions in the recovery of scarce metals and a few critical metals have received attention, whereas the recovery of many others has been barely explored. Therefore, this article explores and details the potential application of microbial biotechnologies in the recovery of critical and scarce metals. In the past decade bioelectrochemical systems have emerged as a new technology platform for metal recovery coupled to the removal of organic matter. Overview of potential applications of microorganisms in critical metal recovery.Engineering of microbe-metal interactions for recovering rare earth elements and platinum group metals.Reductive mineral dissolution is a new dimension to biomining.Bioelectrochemical systems offer a new technology platform in metal recovery.

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, Biofouling and Biofilm Processes Section, Bhabha Atomic Research Centre, Council of Scientific and Industrial Research India, Hydraulic and Environmental Engineering (IHE) Inst. for Water Education
Contributors: Nancharaiah, Y. V., Mohan, S. V., Lens, P. N. L.
Number of pages: 19
Pages: 137-155
Publication date: 2016
Peer-reviewed: Yes

Publication information

Journal: Trends in Biotechnology
Volume: 34
Issue number: 2
ISSN (Print): 0167-7799
Ratings: 
  • Scopus rating (2016): CiteScore 22 SJR 4.203 SNIP 3.169
Original language: English
ASJC Scopus subject areas: Biotechnology, Bioengineering
Keywords: Bioelectrochemical systems, Biomining, Bioprecipitation, Biorecovery, Critical metals, Microbial fuel cells, Platinum group metals, Rare earth elements
Source: Scopus
Source ID: 84961085643

Research output: Contribution to journalArticleScientificpeer-review

High-Yield Excited Triplet States in Pentacene Self-Assembled Monolayers on Gold Nanoparticles through Singlet Exciton Fission

One of the major drawbacks of organic-dye-modified self-assembled monolayers on metal nanoparticles when employed for efficient use of light energy is the fact that singlet excited states on dye molecules can be easily deactivated by means of energy transfer to the metal surface. In this study, a series of 6,13-bis(triisopropylsilylethynyl)pentacene-alkanethiolate monolayer protected gold nanoparticles with different particle sizes and alkane chain lengths were successfully synthesized and were employed for the efficient generation of excited triplet states of the pentacene derivatives by singlet fission. Time-resolved transient absorption measurements revealed the formation of excited triplet states in high yield (172±26%) by suppressing energy transfer to the gold surface.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Research group: Supramolecular photochemistry, Keio University
Contributors: Kato, D., Sakai, H., Tkachenko, N. V., Hasobe, T.
Pages: 5230-5234
Publication date: 2016
Peer-reviewed: Yes

Publication information

Journal: Angewandte Chemie (International Edition)
Volume: 55
Issue number: 17
ISSN (Print): 1433-7851
Ratings: 
  • Scopus rating (2016): CiteScore 18.7 SJR 5.954 SNIP 2.185
Original language: English
ASJC Scopus subject areas: Chemistry(all), Catalysis
Keywords: Gold, Nanoparticles, Pentacene, Self-assembled monolayers, Singlet fission
Source: Scopus
Source ID: 84961773531

Research output: Contribution to journalArticleScientificpeer-review

Superfluorinated Ionic Liquid Crystals Based on Supramolecular, Halogen-Bonded Anions

Unconventional ionic liquid crystals in which the liquid crystallinity is enabled by halogen-bonded supramolecular anions [CnF2n+1-I···I···I-CnF2n+1]- are reported. The material system is unique in many ways, demonstrating for the first time 1)ionic, halogen-bonded liquid crystals, and 2)imidazolium-based ionic liquid crystals in which the occurrence of liquid crystallinity is not driven by the alkyl chains of the cation.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Research group: Supramolecular photochemistry
Contributors: Cavallo, G., Terraneo, G., Monfredini, A., Saccone, M., Priimägi, A., Pilati, T., Resnati, G., Metrangolo, P., Bruce, D. W.
Pages: 6300-6304
Publication date: 2016
Peer-reviewed: Yes

Publication information

Journal: Angewandte Chemie (International Edition)
Volume: 55
Issue number: 21
ISSN (Print): 1433-7851
Ratings: 
  • Scopus rating (2016): CiteScore 18.7 SJR 5.954 SNIP 2.185
Original language: English
ASJC Scopus subject areas: Chemistry(all), Catalysis
Keywords: Fluorophobic effect, Halogen bonding, Ionic liquid crystals, Self-assembly, Supramolecular chemistry
Source: Scopus
Source ID: 84979722901

Research output: Contribution to journalArticleScientificpeer-review

Fire-safe and environmentally friendly nanocomposites based on layered double hydroxides and ethylene propylene diene elastomer

In this work we describe layered double hydroxide (LDH), known as naturally occurring hydrotalcite, based rubber composites that can serve as outstanding fire retardant elastomeric materials. The preparation and detailed characterization of these composites are presented in this study. The inherent slow sulfur cure nature of EPDM rubber is considerably improved by the addition of LDH as realised by the observation of a shortening of the vulcanization time and an improvement of ultimate rheometric torque. This behavior of LDH signifies not only the filler-like character of itself, but also offers vulcanization active surface properties of layered double hydroxide particles. A good rubber-filler interaction was also realised by observing a positive shift of the glass transition temperature of ethylene propylene diene rubber (EPDM) in dynamic mechanical analysis (DMA). The flame retardant property was studied by the cone calorimeter test. The cone calorimeter investigation with sulfur cured gum rubber compounds found a peak heat release rate (PHRR) value of 654 kW m-2. However, at a higher phr loading of Zn-Al LDH i.e., at 40 phr and 100 phr, the PHRR is diminished to 311 kW m-2 and 161 kW m-2, respectively. Thus, this present work can pave the way to fabricate environmentally friendly fire retardant elastomeric composites for various applications.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Materials Science, Research group: Plastics and Elastomer Technology, Institut für Werkstoffwissenschaft, Leibniz-Institut für Polymerforschung Dresden E.V., IMDEA Materials Institute, Cochin University of Science and Technology
Contributors: Basu, D., Das, A., Wang, D. Y., George, J. J., Stöckelhuber, K. W., Boldt, R., Leuteritz, A., Heinrich, G.
Number of pages: 12
Pages: 26425-26436
Publication date: 2016
Peer-reviewed: Yes

Publication information

Journal: RSC Advances
Volume: 6
Issue number: 31
ISSN (Print): 2046-2069
Ratings: 
  • Scopus rating (2016): CiteScore 4.1 SJR 0.889 SNIP 0.757
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Chemistry(all)
Source: Scopus
Source ID: 84961194468

Research output: Contribution to journalArticleScientificpeer-review

Metrics for polyphonic sound event detection

This paper presents and discusses various metrics proposed for evaluation of polyphonic sound event detection systems used in realistic situations where there are typically multiple sound sources active simultaneously. The system output in this case contains overlapping events, marked as multiple sounds detected as being active at the same time. The polyphonic system output requires a suitable procedure for evaluation against a reference. Metrics from neighboring fields such as speech recognition and speaker diarization can be used, but they need to be partially redefined to deal with the overlapping events. We present a review of the most common metrics in the field and the way they are adapted and interpreted in the polyphonic case. We discuss segment-based and event-based definitions of each metric and explain the consequences of instance-based and class-based averaging using a case study. In parallel, we provide a toolbox containing implementations of presented metrics.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Signal Processing, Research group: Audio research group
Contributors: Mesaros, A., Heittola, T., Virtanen, T.
Publication date: 2016
Peer-reviewed: Yes

Publication information

Journal: Applied Sciences
Volume: 6
Issue number: 6
Article number: 162
ISSN (Print): 2076-3417
Ratings: 
  • Scopus rating (2016): SJR 0.315 SNIP 0.791
Original language: English
ASJC Scopus subject areas: Fluid Flow and Transfer Processes, Process Chemistry and Technology, Computer Science Applications, Engineering(all), Materials Science(all), Instrumentation
Keywords: Audio content analysis, Audio signal processing, Computational auditory scene analysis, Evaluation of sound event detection, Everyday sounds, Pattern recognition, Polyphonic sound event detection, Sound events
Source: Scopus
Source ID: 84973574836

Research output: Contribution to journalArticleScientificpeer-review

Decoding the Morphological Diversity in Two Dimensional Crystalline Porous Polymers by Core Planarity Modulation

Two new chemically stable triazine- and phenyl-core-based crystalline porous polymers (CPPs) have been synthesized using a single-step template-free solvothermal route. Unique morphological diversities were observed for these CPPs [2,3-DhaTta (ribbon) and 2,3-DhaTab (hollow sphere)] by simply altering the linker planarity. A detailed time-dependent study established a significant correlation between the molecular level structures of building blocks with the morphology of CPPs. Moreover, a DFT study was done for calculating the interlayer stacking energy, which revealed that the extent of stacking efficiency is responsible for governing the morphological diversity in these CPPs.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: CSIR-National Chemical Laboratory, Indian Institute of Technology Kanpur, Indian Institute of Technology Bombay, Jacobs University Bremen, Polymer Science and Engineering Division
Contributors: Halder, A., Kandambeth, S., Biswal, B. P., Kaur, G., Roy, N. C., Addicoat, M., Salunke, J. K., Banerjee, S., Vanka, K., Heine, T., Verma, S., Banerjee, R.
Number of pages: 5
Pages: 7806-7810
Publication date: 2016
Peer-reviewed: Yes

Publication information

Journal: Angewandte Chemie (International Edition)
Volume: 55
Issue number: 27
ISSN (Print): 1433-7851
Ratings: 
  • Scopus rating (2016): CiteScore 18.7 SJR 5.954 SNIP 2.185
Original language: English
ASJC Scopus subject areas: Catalysis, Chemistry(all)
Keywords: covalent organic frameworks, density functional calculations, dihedral angles, morphology, stacking interactions
Source: Scopus
Source ID: 84960155135

Research output: Contribution to journalArticleScientificpeer-review

Enhanced adsorption of orthophosphate and copper onto hydrochar derived from sewage sludge by KOH activation

Hydrothermal carbonization producing hydrochar from organic waste is increasingly gaining attention to deal with the challenge of excess waste activated sludge produced during centralized aerobic wastewater treatment. Hydrochar is used as an adsorbent for the removal of organics, metals and biotic contaminants. This study demonstrated the application of KOH activated hydrochar, called enhanced hydrochar (EHC) derived from sewage sludge, for the removal of orthophosphate from wastewater by means of batch adsorption, zetametry and infrared spectroscopy. The maximum Qe-PO4 3− of EHC was 14.3 mg orthophosphate adsorbed per g of EHC when the initial orthophosphate concentration was increased to 150 mg L−1. The application of orthophosphate removal by EHC from the effluent of a constructed wetland was demonstrated by achieving more than 97% orthophosphate removal at an EHC dosage of 6.0 g L−1 and an initial orthophosphate concentration of 13.1 mg L−1. pH dependent adsorption experiments and infrared spectroscopy showed the orthophosphate removal by EHC was due to the replacement of hydroxyl groups by orthophosphate in the EHC. Acid-base titration showed the KOH washing of the raw hydrochar (RHC) led to a 1.7 times increase in the hydroxyl groups in EHC compared to RHC. This study further confirmed the higher uptake capacity of EHC compared to RHC towards copper as a model divalent cation. EHC can thus be applied for the removal of both anions (orthophosphate) and cations (copper) from wastewater.

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, Hydraulic and Environmental Engineering (IHE) Inst. for Water Education, Zurich University of Applied Sciences
Contributors: Spataru, A., Jain, R., Chung, J. W., Gerner, G., Krebs, R., Lens, P. N. L.
Number of pages: 8
Pages: 101827-101834
Publication date: 2016
Peer-reviewed: Yes

Publication information

Journal: RSC Advances
Volume: 6
Issue number: 104
ISSN (Print): 2046-2069
Ratings: 
  • Scopus rating (2016): CiteScore 4.1 SJR 0.889 SNIP 0.757
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all)
Source: Scopus
Source ID: 84994048409

Research output: Contribution to journalArticleScientificpeer-review

Nonlinear transmittance and optical power limiting in magnesium ferrite nanoparticles: effects of laser pulsewidth and particle size

We report comparative measurements of size dependent nonlinear transmission and optical power limiting in nanocrystalline magnesium ferrite (MgFe2O4) particles excited by short (nanosecond) and ultrashort (femtosecond) laser pulses. A standard sol-gel technique is employed to synthesize particles in the size range of 10-50 nm, using polyvinyl alcohol as the chelating agent. The structure and morphology of the samples are studied using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Growth of the particles in time is tracked through Fourier transform infrared spectroscopy. Nonlinear transmission measurements have been carried out using the open aperture Z-scan technique employing 532 nm, 5 nanosecond pulses and 800 nm, 100 femtosecond pulses, respectively. The measured optical nonlinearity is primarily of a reverse saturable absorption (RSA) nature, arising mostly from excited state absorption for nanosecond excitation, and two-photon absorption for femtosecond excitation. The optical limiting efficiency is found to increase with particle size for both cases. The calculated nonlinear parameters indicate that these materials are potential candidates for optical limiting applications.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Photonics, National Institute of Technology Karnataka, International and Inter University Centre for Nanoscience and Nanotechnology, Mahatma Gandhi University, Raman Research Institute
Contributors: Perumbilavil, S., Sridharan, K., Abraham, A. R., Janardhanan, H. P., Kalarikkal, N., Philip, R.
Number of pages: 8
Pages: 106754-106761
Publication date: 2016
Peer-reviewed: Yes

Publication information

Journal: RSC Advances
Volume: 6
Issue number: 108
ISSN (Print): 2046-2069
Ratings: 
  • Scopus rating (2016): CiteScore 4.1 SJR 0.889 SNIP 0.757
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all)
Source: Scopus
Source ID: 84995977139

Research output: Contribution to journalArticleScientificpeer-review

The formation and physical properties of the particle emissions from a natural gas engine

Natural gas engine particle emissions were studied using an old gasoline engine modified to run with natural gas. The tests were steady-state tests performed on two different low loads in an engine dynamometer. Exhaust particle number concentration, size distribution, volatility and electric charge were measured. Exhaust particles were observed to have peak diameters below 10 nm. To get the full picture of particle emissions from natural gas engines, size range 1-5 nm is relevant and important to take into consideration. A particle size magnifier (PSM) was used in this engine application for measuring particles smaller than 3 nm and it proved to be a useful instrument when measuring natural gas engine exhaust particles. It is concluded that the detected particles probably originated from the engine cylinders or their vicinity and grew to detectable sizes in the sampling process because a small fraction of the particles were observed to carry electric charge and the particles did not evaporate totally at 265°C.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Physics, Research area: Aerosol Physics, Research group: The Instrumentation, Emissions, and Atmospheric Aerosols Group, Engineering materials science and solutions (EMASS), Urban circular bioeconomy (UrCirBio), Atmospheric Composition Research, VTT Technical Research Centre of Finland, Finnish Meteorological Institute
Contributors: Alanen, J., Saukko, E., Lehtoranta, K., Murtonen, T., Timonen, H., Hillamo, R., Karjalainen, P., Kuuluvainen, H., Harra, J., Keskinen, J., Rönkkö, T.
Number of pages: 7
Pages: 155-161
Publication date: 15 Dec 2015
Peer-reviewed: Yes

Publication information

Journal: Fuel
Volume: 162
ISSN (Print): 0016-2361
Ratings: 
  • Scopus rating (2015): CiteScore 6.9 SJR 1.781 SNIP 2.111
Original language: English
ASJC Scopus subject areas: Fuel Technology, Energy Engineering and Power Technology, Chemical Engineering(all), Organic Chemistry
Keywords: Fine particle emission, Internal combustion engine, Natural gas, Particle formation
Source: Scopus
Source ID: 84941782885

Research output: Contribution to journalArticleScientificpeer-review

Modeling carbon dioxide transport in PDMS-based microfluidic cell culture devices

Maintaining a proper pH level is crucial for successful cell culturing. Mammalian cells are commonly cultured in incubators, where the cell culture medium is saturated with a mixture of air and 5% carbon dioxide (CO<inf>2</inf>). Therefore, to keep cell culture medium pH in an acceptable level outside these incubators, a suitable CO<inf>2</inf> concentration must be dissolved in the medium. However, it can be very difficult to control and measure precisely local concentration levels. Furthermore, possible undesired concentration gradients generated during long-term cell culturing are almost impossible to detect. Therefore, we have developed a computational model to estimate CO<inf>2</inf> transport in silicone-based microfluidic devices. An extensive set of experiments was used to validate the finite element model. The model parameters were obtained using suitable measurement set-ups and the model was validated using a fully functional cell cultivation device. The predictions obtained by the simulations show very good responses to experiments. It is shown in this paper how the model helps to understand the dynamics of CO<inf>2</inf> transport in silicone-based cell culturing devices possessing different geometries, thus providing cost-effective means for studying different device designs under a variety of experimental conditions without the need of actual testing. Finally, based on the results from the computational model, an alternative strategy for feeding CO<inf>2</inf> is proposed to accelerate the system performance such that a faster and more uniform CO<inf>2</inf> concentration response is achieved in the area of interest.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Automation Science and Engineering, Department of Materials Science, Research group: Paper Converting and Packaging, BioMediTech, Integrated Technologies for Tissue Engineering Research (ITTE), BioMediTech
Contributors: Mäki, A. J., Peltokangas, M., Kreutzer, J., Auvinen, S., Kallio, P.
Number of pages: 10
Pages: 515-524
Publication date: 1 Dec 2015
Peer-reviewed: Yes

Publication information

Journal: Chemical Engineering Science
Volume: 137
ISSN (Print): 0009-2509
Ratings: 
  • Scopus rating (2015): CiteScore 5 SJR 1.022 SNIP 1.563
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Chemistry(all), Applied Mathematics, Industrial and Manufacturing Engineering
Keywords: Carbon dioxide, Finite element method, Mass transport, Microfluidics cell culturing, Numerical simulation, pH
Electronic versions: 
URLs: 

Bibliographical note

ORG=ase,0.9
ORG=mol,0.1

Source: Scopus
Source ID: 84938149959

Research output: Contribution to journalArticleScientificpeer-review

Polypyrrole coating on poly-(lactide/glycolide)-β-tricalcium phosphate screws enhances new bone formation in rabbits

Polypyrrole (PPy) has gained interest as an implant material due to its multifunctional properties and its high compatibility with several cell and tissue types. For the first time, the biocompatibility and osteointegration of PPy coating, incorporated with chondroitin sulfate (CS), were studied in vivo by implanting PPy-coated bioabsorbable bone fixation composite screws of poly-(lactide/glycolide) copolymer (PLGA) and β-tricalcium phosphate (TCP) into New Zealand white rabbits. Uncoated bioabsorbable polymer composite screws and commercially available stainless steel cortical screws were used as reference implants. The rabbits were euthanized 12 and 26 weeks after the implantation. The systemic effects were evaluated from food and water consumption, body weight, body temperature, clinical signs, blood samples, internal organ weights, and histological examination. Local effects were studied from bone tissue and surrounding soft tissue histology. New bone formation was evaluated by micro-computed tomography, tetracycline labeling and torsion tests. Torsion tests were performed in order to capture the peak value of the torsion force during the course of the screw's loosening. The coated screws induced significantly more bone formation than the uncoated screws. In addition, none of the implants induced any systemic or local toxicity. The results suggest that PPy is biocompatible with bone tissue and is a potential coating for enhancing osteointegration in orthopedic implants.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Electronics and Communications Engineering, Research group: Computational Biophysics and Imaging Group, Research group: Biomaterials and Tissue Engineering Group, BioMediTech, Integrated Technologies for Tissue Engineering Research (ITTE), Fudan University, University of Wollongong, VTT Technical Research Centre of Finland, Tampere University Hospital, University of Oulu, Univ Helsinki, Helsinki University Central Hospital, University of Helsinki, Cent Hosp, Dept Med, Div Nephrol, University of Twente
Contributors: Zhao, M. D., Björninen, M., Cao, L., Wang, H. R., Pelto, J., Li, X. Q., Hyttinen, J., Jiang, Y. Q., Kellomäki, M., Miettinen, S., Sándor, G. K., Seppänen, R., Haimi, S., Dong, J.
Publication date: 27 Nov 2015
Peer-reviewed: Yes

Publication information

Journal: Biomedical Materials
Volume: 10
Issue number: 6
Article number: 065016
ISSN (Print): 1748-6041
Ratings: 
  • Scopus rating (2015): CiteScore 5.1 SJR 1.118 SNIP 1.118
Original language: English
ASJC Scopus subject areas: Bioengineering, Biomaterials, Biomedical Engineering
Keywords: absorbable screw, biocompatibility, in vivo, osteointegration, polypyrrole (PPy)

Bibliographical note

EXT="Pelto, Jani"

Source: Scopus
Source ID: 84950121168

Research output: Contribution to journalArticleScientificpeer-review

Graphene-intercalated Fe2O3/TiO2 heterojunctions for efficient photoelectrolysis of water

Interfacial modification of α-Fe2O3/TiO2 multilayer photoanodes by intercalating few-layer graphene (FLG) was found to improve water splitting efficiency due to superior transport properties, when compared to individual iron and titanium oxides and heterojunctions thereof. Both metal oxides and graphene sheets were grown by plasma-enhanced chemical vapor deposition. Compared to the onset potential achieved for α-Fe2O3 films (1 V vs. RHE), the α-Fe2O3/TiO2 bilayer structure yielded a better onset potential (0.3 V vs. RHE). Heterojunctioned bilayers exhibited a higher photocurrent density (0.32 mA cm-2 at 1.23 V vs. RHE) than the single α-Fe2O3 layer (0.22 mA cm-2 at 1.23 V vs. RHE), indicating more efficient light harvesting and higher concentration of photogenerated charge carriers. For more efficient charge transport at the interface, a few layer graphene sheet was intercalated into the α-Fe2O3/TiO2 interface, which substantially increased the photocurrent density to 0.85 mA cm-2 (1.23 V vs. RHE) and shifted the onset potential (0.25 V vs. RHE). Ultrafast transient absorption spectroscopy studies indicated that the incorporation of FLG between the α-Fe2O3 and TiO2 layers resulted in reduced recombination in the α-Fe2O3 layer. The results showed that graphene intercalation improved the charge separation and the photocurrent density of the FTO/α-Fe2O3/FLG/TiO2 system.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Research group: Supramolecular photochemistry, Universitat zu Koln, Institute of Inorganic Chemistry, Ruhr-Universität Bochum
Contributors: Kaouk, A., Ruoko, T. P., Gönüllü, Y., Kaunisto, K., Mettenbörger, A., Gurevich, E., Lemmetyinen, H., Ostendorf, A., Mathur, S.
Number of pages: 7
Pages: 101401-101407
Publication date: 13 Nov 2015
Peer-reviewed: Yes

Publication information

Journal: RSC Advances
Volume: 5
Issue number: 123
ISSN (Print): 2046-2069
Ratings: 
  • Scopus rating (2015): CiteScore 3.5 SJR 0.947 SNIP 0.838
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Chemistry(all)
Electronic versions: 
Source: Scopus
Source ID: 84948652698

Research output: Contribution to journalArticleScientificpeer-review

Simultaneous nutrient removal and lipid production with Chlorella vulgaris on sterilized and non-sterilized anaerobically pretreated piggery wastewater

Piggery wastewater is a potent nutrient source for microalgal lipid production. Wastewater has been usually sterilized when used for microalgal cultivation. This is uneconomical in large-scale applications. Therefore, lipid productivity of Chlorella vulgaris CY5 using sterilized and non-sterilized diluted anaerobically pretreated piggery wastewater was studied in batch reactors. The maximum average lipid productivity was obtained after 12 days of incubation and it was higher with the sterilized wastewater than with the non-sterilized one (117g/L/d vs. 91.3g/L/d), due to the higher biomass concentration. Because of the unexpected increase of dissolved organic carbon (DOC) in the cultures, second experiment was conducted to characterize the composition of produced DOC in non-sterilized wastewater. Carbohydrate content increased in the liquid phase but decreased in the biomass after nitrogen had been exhausted. After 12 days of incubation, soluble chemical oxygen demand (COD<inf>s</inf>) was 414±56mg/L, biomass production was 2.8±0.15g/L, and lipid content was 30.3±1.2wt%. Average lipid productivity from day zero to day 12 was 70.5±1.1g/L/d. C. vulgaris removed nutrients from the non-sterilized wastewater and produced oleaginous biomass, although the lipid productivity was higher with sterilized wastewater.

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, Urban circular bioeconomy (UrCirBio), Center of Bioscience and Biotechnology, Research Center for Energy Technology and Strategy, National Cheng Kung University, Department of Environmental Engineering, Department of Chemical Engineering
Contributors: Marjakangas, J. M., Chen, C. Y., Lakaniemi, A. M., Puhakka, J. A., Whang, L. M., Chang, J. S.
Number of pages: 8
Pages: 177-184
Publication date: 5 Nov 2015
Peer-reviewed: Yes
Early online date: 23 Jul 2015

Publication information

Journal: Biochemical Engineering Journal
Volume: 103
ISSN (Print): 1369-703X
Ratings: 
  • Scopus rating (2015): CiteScore 4.6 SJR 0.952 SNIP 1.075
Original language: English
ASJC Scopus subject areas: Biotechnology, Bioengineering, Biomedical Engineering, Environmental Engineering
Keywords: Aerobic process, Lipid production, Microalgae, Piggery wastewater, Sterilization, Wastewater treatment
Source: Scopus
Source ID: 84939202209

Research output: Contribution to journalArticleScientificpeer-review

Tri-functionality of Fe3O4-embedded carbon microparticles in microalgae harvesting

Microalgae have received significant attention as promising resources for biodiesel. However, the downstream processes for the production of biodiesel, which range from cultivation, harvesting, dewatering, and lipid extraction to oil upgrading, are economically impracticable and can be improved. Therefore, efficient microalgal harvesting and integrated technologies are required to realize microalgae-based biodiesel. Herein, tri-functional (cationic, magnetic, and lipophilic) carbon microparticles filled with magnetite (Fe<inf>3</inf>O<inf>4</inf>) are synthesized through one-step aerosol spray pyrolysis and applied in microalgal harvesting and serial microalgal lipid entrapment. Carbon microparticles are tri-functional in the following respects: (i) the cationic carbon microparticles facilitate flocculation with anionic microalgae due to electrostatic attractions; (ii) the magnetic properties of the carbon microparticles, owing to embedded magnetites, enable the separation of microalgal flocs from low concentration cultures (~2gL<sup>-1</sup>) with a separation efficiency of 99%; and (iii) the lipophilicity enables the recovery of lipid droplets extracted from oleaginous microalgae. Microalgal lipids are directly separated through adsorption onto magnetic carbon microparticles from concentrated microalgal slurries after harvesting. The tri-functionality may facilitate the integrated use of magnetic carbon microparticles in microalgal biorefineries and the tri-functional microparticles could potentially be applied in various areas such as biomedicine, catalysis, magnetism, energy materials, and environmental remediation.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Urban circular bioeconomy (UrCirBio), KAIST, Korea Institute of Energy Research
Contributors: Seo, J. Y., Lee, K., Ramasamy, P., Kim, B., Lee, S. Y., Oh, Y. K., Park, S. B.
Number of pages: 9
Pages: 206-214
Publication date: 5 Nov 2015
Peer-reviewed: Yes

Publication information

Journal: Chemical Engineering Journal
Volume: 280
ISSN (Print): 1385-8947
Ratings: 
  • Scopus rating (2015): CiteScore 8.6 SJR 1.676 SNIP 1.912
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Chemistry(all), Industrial and Manufacturing Engineering, Environmental Chemistry
Keywords: Aerosol spray pyrolysis, Cationic functionality, Lipophilicity, Magnetic materials, Microalgae harvesting
Source: Scopus
Source ID: 84933567826

Research output: Contribution to journalArticleScientificpeer-review

Effect of rubber polarity on selective wetting of carbon nanotubes in ternary blends

Based on atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR) analysis of the rubber-filler gel (wetting concept) the kinetics of selective wetting of carbon nanotubes (CNTs) in ternary styrene butadiene rubber (SBR)/butadiene rubber (BR)/natural rubber (NR) blends was qualitatively and quantitatively characterized. Almost all CNTs are found to be wetted by the non-polar NR but not by the other non-polar rubber like BR or weakly polar SBR. It was proposed that phospholipids, which are linked to the α-terminal of NR can interact with the CNT surface through cation-π interactions forming strong bonding between NR and CNTs. Using the corrected surface tension value of NR, which involves the effect of phospholipids found in our previous work the selective wetting of CNTs in ternary rubber blends can be well predicted using the Z-model for a thermodynamic equilibrium state. By replacing the non-polar BR by a polar rubber like nitrile butadiene rubber (NBR) as a blend component CNTs are wetted by NBR slightly more than by NR thanks to the strong interaction between CNTs and nitrile groups of NBR. SBR remains unbound to CNTs in both blends.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Engineering materials science and solutions (EMASS), Institut für Polymerwerkstoffe E.V., Martin-Luther-University Halle-Wittenberg, Fraunhofer IWM, Vodafone Department of Mobile Communications Systems, Leibniz-Institut für Polymerforschung Dresden E.V., Vietnamese Academy of Science and Technology Institute of Chemistry, Polymer Service GmbH Merseburg
Contributors: Le, H. H., Parsaker, M., Sriharish, M. N., Henning, S., Menzel, M., Wießner, S., Das, A., Do, Q. K., Heinrich, G., Radusch, H. J.
Number of pages: 12
Pages: 960-971
Publication date: 1 Nov 2015
Peer-reviewed: Yes

Publication information

Journal: Express Polymer Letters
Volume: 9
Issue number: 11
ISSN (Print): 1788-618X
Ratings: 
  • Scopus rating (2015): CiteScore 5.4 SJR 0.929 SNIP 1.583
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Physical and Theoretical Chemistry, Polymers and Plastics, Organic Chemistry, Materials Chemistry
Keywords: Carbon nanotubes, Manocomposites, Rubber blends, Selective filler wetting
Source: Scopus
Source ID: 84940868023

Research output: Contribution to journalArticleScientificpeer-review

Comparison of different cationized proteins as biomaterials for nanoparticle-based ocular gene delivery

Cationized polymers have been proposed as transfection agents for gene therapy. The present work aims to improve the understanding of the potential use of different cationized proteins (atelocollagen, albumin and gelatin) as nanoparticle components and to investigate the possibility of modulating the physicochemical properties of the resulting nanoparticle carriers by selecting specific protein characteristics in an attempt to improve current ocular gene-delivery approaches. The toxicity profiles, as well as internalization and transfection efficiency, of the developed nanoparticles can be modulated by modifying the molecular weight of the selected protein and the amine used for cationization. The most promising systems are nanoparticles based on intermediate molecular weight gelatin cationized with the endogenous amine spermine, which exhibit an adequate toxicological profile, as well as effective association and protection of pDNA or siRNA molecules, thereby resulting in higher transfection efficiency and gene silencing than the other studied formulations.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Integrated Technologies for Tissue Engineering Research (ITTE), Federal University of Rio Grande do Sul, University of Santiago de Compostela (USC), University Clinical Hospital of Santiago de Compostela (IDIS)
Contributors: Zorzi, G. K., Párraga, J. E., Seijo, B., Sanchez, A.
Number of pages: 9
Pages: 533-541
Publication date: 1 Nov 2015
Peer-reviewed: Yes

Publication information

Journal: Colloids and Surfaces B: Biointerfaces
Volume: 135
ISSN (Print): 0927-7765
Ratings: 
  • Scopus rating (2015): CiteScore 6.9 SJR 1.085 SNIP 1.244
Original language: English
ASJC Scopus subject areas: Biotechnology, Surfaces and Interfaces, Physical and Theoretical Chemistry, Colloid and Surface Chemistry
Keywords: Cationized proteins, Gene therapy, Nanoparticles, pDNA, siRNA
Source: Scopus
Source ID: 84939622417

Research output: Contribution to journalArticleScientificpeer-review

Submolecular Plasticization Induced by Photons in Azobenzene Materials

We demonstrate experimentally for the first time that the illumination of azobenzene derivatives leads to changes in molecular environment similar to those observed on heating but that are highly heterogeneous at the submolecular scale. This localized photoplasticization, which can be associated with a free volume gradient, helps to understand the puzzling phenomenon of photoinduced macroscopic material flow and photoexpansion upon illumination far below the glass transition temperature (Tg). The findings stem from the correlation of infrared (IR) spectral band shifts measured upon illumination with those measured at controlled temperatures for two amorphous DR1-functionalized azo derivatives, a polymer, pDR1A, and a molecular glass, gDR1. This new approach reveals that IR spectroscopy can be used as an efficient label-free molecular-scale thermometer that allows the assignment of an effective temperature (Teff) to each moiety in these compounds when irradiated. While no band shift is observed upon illumination for the vibrational modes assigned to backbone moieties of pDR1A and gDR1 and a small band shift is found for the spacer moiety, dramatic band shifts are recorded for the azo moiety, corresponding to an increase in Teff of up to nearly 200 °C and a molecular environment that is equivalent to thermal heating well above the bulk Tg of the material. An irradiated azo-containing material thus combines characteristic properties of amorphous materials both below and above its bulk Tg. The direct measurement of Teff is a powerful probe of the local environment at the submolecular scale, paving the way toward better rationalization of photoexpansion and the athermal malleability of azo-containing materials upon illumination below their Tg.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Frontier Photonics, Département de Chimie, Succ. Centre-Ville, Royal Military College of Canada
Contributors: Vapaavuori, J., Laventure, A., Bazuin, C. G., Lebel, O., Pellerin, C.
Number of pages: 8
Pages: 13510-13517
Publication date: 28 Oct 2015
Peer-reviewed: Yes

Publication information

Journal: Journal of the American Chemical Society
Volume: 137
Issue number: 42
ISSN (Print): 0002-7863
Ratings: 
  • Scopus rating (2015): CiteScore 22.4 SJR 6.775 SNIP 2.6
Original language: English
ASJC Scopus subject areas: Catalysis, Chemistry(all), Biochemistry, Colloid and Surface Chemistry
Source: Scopus
Source ID: 84946020103

Research output: Contribution to journalArticleScientificpeer-review

Cultivation of Nannochloropsis for eicosapentaenoic acid production in wastewaters of pulp and paper industry

The eicosapentaenoic acid (EPA) containing marine microalga Nannochloropsis oculata was grown in an effluent from anaerobic digestion of excess activated sludge from a wastewater treatment plant serving a combination of a pulp and a paper mill and a municipality (digester effluent, DE), mixed with the effluent of the same wastewater treatment plant. The maximum specific growth rate and photosynthesis of N. oculata were similar in the DE medium and in artificial sea water medium (ASW) but after 7. days, algae grown in the DE medium contained seven times more triacylglycerols (TAGs) per cell than cells grown in ASW, indicating mild stress in the DE medium. However, the volumetric rate of EPA production was similar in the ASW and DE media. The results suggest that N. oculata could be used to produce EPA, utilizing the nutrients available after anaerobic digestion of excess activated sludge of a pulp and paper mill.

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, Urban circular bioeconomy (UrCirBio), University of Turku, Department of Biochemistry/Molecular Plant Biology, Department of Biochemistry/Food Chemistry and Food Development
Contributors: Polishchuk, A., Valev, D., Tarvainen, M., Mishra, S., Kinnunen, V., Antal, T., Yang, B., Rintala, J., Tyystjärvi, E.
Number of pages: 8
Pages: 469-476
Publication date: 1 Oct 2015
Peer-reviewed: Yes
Early online date: 2 Jul 2015

Publication information

Journal: Bioresource Technology
Volume: 193
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2015): CiteScore 9.2 SJR 2.243 SNIP 1.899
Original language: English
ASJC Scopus subject areas: Bioengineering, Environmental Engineering, Waste Management and Disposal
Keywords: Eicosapentaenoic acid, Nannochloropsis, Paper mill, Pulp mill, Wastewater
Source: Scopus
Source ID: 84936059366

Research output: Contribution to journalArticleScientificpeer-review

Molecular Design of Light-Responsive Hydrogels, for in Situ Generation of Fast and Reversible Valves for Microfluidic Applications

Reversible light-responsive hydrogel valves with response characteristics compatible for microfluidics have been obtained by optimization of molecular design of spiropyran photoswitches and gel composition. Self-protonating gel formulations were exploited, wherein acrylic acid was copolymerized in the hydrogel network as an internal proton donor, to achieve a swollen state of the hydrogel in water at neutral pH. Light-responsive properties were endowed upon the hydrogels by copolymerization of spiropyran chromophores, using electron withdrawing and donating groups to tune the gel-swelling and shrinkage behavior. In all cases, the shrinkage was determined by the water diffusion rate, while for the swelling the isomerization kinetics is the rate-determining step. For one hydrogel, reversible and reproducible volume changes were observed. Finally, gel-valves integrated within microfluidic channels were fabricated, allowing reversible and repeatable operation, with opening and closing of the valve in minutes.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Eindhoven University of Technology, Dublin City University
Contributors: Ter Schiphorst, J., Coleman, S., Stumpel, J. E., Ben Azouz, A., Diamond, D., Schenning, A. P. H. J.
Number of pages: 7
Pages: 5925-5931
Publication date: 8 Sep 2015
Peer-reviewed: Yes

Publication information

Journal: Chemistry of Materials
Volume: 27
Issue number: 17
ISSN (Print): 0897-4756
Ratings: 
  • Scopus rating (2015): CiteScore 12.8 SJR 3.958 SNIP 2.038
Original language: English
ASJC Scopus subject areas: Materials Chemistry, Chemical Engineering(all), Chemistry(all)
Source: Scopus
Source ID: 84941088068

Research output: Contribution to journalArticleScientificpeer-review

Effects of anode potentials on bioelectrogenic conversion of xylose and microbial community compositions

The results on the effects of different anode potentials on current densities, coulombic efficiencies and microbial communities are contradictory and have not been studied with xylose, an important constituent of lignocellulosic materials. In this study, the effects of different anode potentials (+0.2, 0 and -0.2V vs. Ag/AgCl) on current generation, xylose degradation and microbial communities were examined with an exoelectrogenic enrichment culture originating from anaerobic sludge. Anode potential of +0.2V (vs. Ag/AgCl) resulted in the highest current density and coulombic efficiency of 1.5±0.2A/m<sup>2</sup> and 62±11%, respectively, and there was no accumulation of soluble metabolites. With anode potentials of 0 and -0.2V the current densities remained low and acetate, butyrate and propionate were detected in the end of batch runs. Different anode potentials resulted in substantial differences in the anodic bacterial species. At more positive anode potentials, Ochrobactrum intermedium reported to be capable of direct electron transfer dominated. At more negative anode potentials, a known mediator-producer, Alcaligenes faecalis, and Desulfitobacterium hafnience, that has been reported to use mediated electron transfer, were detected. This study shows that the anode potential has a substantial effect on microbial communities and on xylose metabolism.

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, Urban circular bioeconomy (UrCirBio)
Contributors: Kokko, M. E., Mäkinen, A. E., Sulonen, M. L. K., Puhakka, J. A.
Number of pages: 5
Pages: 248-252
Publication date: 5 Sep 2015
Peer-reviewed: Yes
Early online date: 24 Jun 2015

Publication information

Journal: Biochemical Engineering Journal
Volume: 101
ISSN (Print): 1369-703X
Ratings: 
  • Scopus rating (2015): CiteScore 4.6 SJR 0.952 SNIP 1.075
Original language: English
ASJC Scopus subject areas: Biotechnology, Bioengineering, Biomedical Engineering, Environmental Engineering
Keywords: Anaerobic processes, Anode potential, Batch processing, Biocatalysis, Bioconversion, Microbial fuel cell
Source: Scopus
Source ID: 84936752873

Research output: Contribution to journalArticleScientificpeer-review

Enhanced photoactive and photoelectrochemical properties of TiO2 sol-gel coated steel by the application of SiO2 intermediate layer

Photocatalysis is a promising solution for purifying air and water from pollutants, yet more efficient photocatalytic materials are needed. A new approach is proposed in this paper for enhancing the photoactive and photoelectrical properties of anatase TiO2 films by applying an intermediate SiO2 film between the TiO2 film and the stainless steel substrate. TiO2 and SiO2 coatings are synthesized by a sol-gel method and the thickness of TiO2 film is varied in order to obtain improved understanding on the role of thickness in photocatalytic and electrochemical performance. The obtained coatings are systematically characterized in terms of microstructure using such techniques as field-emission scanning electron microscopy (FE-SEM), Raman spectroscopy and X-ray diffraction (XRD), that demonstrate, e.g., the anatase phase structure of the TiO2 films. The enhanced photocatalytic properties of SiO2/TiO2 coatings as compared to TiO2 films are verified using methylene blue (MB) discoloration tests, while the improved photoelectrochemical properties are shown by potentiodynamic i-V scans, open circuit potential (OCP) monitoring and electrochemical impedance spectroscopy (EIS). We attribute the beneficial effect of the intermediate SiO2 film on the photocatalytic and photoelectrochemical performance to the high electrical resistance of the SiO2 that imposes a high-energy barrier for electron transfer and, therefore, (partly) insulates the TiO2 film from the substrate and acts as a capacitor for photo-generated electrons under illumination. The presented results show an effective way of enhancing the photocatalytic performance of anatase TiO2 films.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Engineering materials science and solutions (EMASS), Frontier Photonics, Department of Materials Science, Research group: Ceramic materials, Optoelectronics Research Centre, Research group: Nanophotonics, Research group: Surface Engineering, Research group: Materials Characterization
Contributors: Nikkanen, J. P., Huttunen-Saarivirta, E., Salminen, T., Hyvärinen, L., Honkanen, M., Isotahdon, E., Heinonen, S., Levänen, E.
Number of pages: 11
Pages: 533-543
Publication date: 1 Sep 2015
Peer-reviewed: Yes

Publication information

Journal: Applied Catalysis B-Environmental
Volume: 174-175
ISSN (Print): 0926-3373
Ratings: 
  • Scopus rating (2015): CiteScore 12.7 SJR 2.326 SNIP 2.213
Original language: English
ASJC Scopus subject areas: Catalysis, Process Chemistry and Technology, Environmental Science(all)
Keywords: Electrical resistance, Electrochemical impedance spectroscopy, Photocatalysis, Substrate, Titanium dioxide

Bibliographical note

ORG=mol,0.5
ORG=orc,0.5

Source: Scopus
Source ID: 84937762118

Research output: Contribution to journalArticleScientificpeer-review

Searching for a robust strategy for minimizing alkali chlorides in fluidized bed boilers during burning of high SRF-energy-share fuel

To meet the increasing volume of waste to be treated via energy recovery, high SRF-energy-share fuel is being fired in conventional waste-to-energy facilities. In this work, corrosion related risk during firing of 70 e-% share (target fuel) is studied and compared against the base case fuel containing 50 e-% share. Cl and S concentration is highest in the target fuel as a direct result of increasing the proportion of SRF in the fuel mixture. Br, Zn and Pb showed the same trend. Meanwhile, the concentration of Na, K, Al and Si are highly dependent on the type of the SRF fired. The corrosion risk of the base and target fuels are analyzed using the composition of the fine aerosol fraction and deposit samples measured near the vicinity of the superheater. Surprisingly aerosols for the target fuel are less risky - having less Cl and more S, than that of the base fuel. The effects of sulfur based additives - elemental sulfur and sulfate injection, and fuel substitution on the risk of superheater corrosion are likewise analyzed. All these strategies can reduce the concentration of Cl in the aerosols, however it is concluded that sulfate injection is considered as a robust strategy for mitigating alkali chloride formation. Sulfate injection is able to reduce Cl in the aerosols and deposits regardless of the quality of the fuel mixture. Robust strategies are important in ensuring the boiler performance during high SRF-energy share firing. An attempt of linking the quality of the deposits and the properties of the flue gas and aerosols around the superheater using partial least squares regression is also presented.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Urban circular bioeconomy (UrCirBio), University of Jyväskylä, Valmet Technologies Oy, VTT Technical Research Centre of Finland, Department of Chemistry, Renewable Natural Resources and Chemistry of Living Environment, Stora Enso
Contributors: Bajamundi, C. J. E., Vainikka, P., Hedman, M., Silvennoinen, J., Heinanen, T., Taipale, R., Konttinen, J.
Number of pages: 12
Pages: 25-36
Publication date: 1 Sep 2015
Peer-reviewed: Yes

Publication information

Journal: Fuel
Volume: 155
ISSN (Print): 0016-2361
Ratings: 
  • Scopus rating (2015): CiteScore 6.9 SJR 1.781 SNIP 2.111
Original language: English
ASJC Scopus subject areas: Fuel Technology, Energy Engineering and Power Technology, Chemical Engineering(all), Organic Chemistry
Keywords: Alkali chloride mitigation, Corrosion, SRF, Waste-to-energy
Source: Scopus
Source ID: 84928243284

Research output: Contribution to journalArticleScientificpeer-review

Surface Modified Biodegradable Electrospun Membranes as a Carrier for Human Embryonic Stem Cell-Derived Retinal Pigment Epithelial Cells

Human embryonic stem cell-derived retinal pigment epithelial (hESC-RPE) cells are currently undergoing clinical trials to treat retinal degenerative diseases. Transplantation of hESC-RPE cells in conjuction with a supportive biomaterial carrier holds great potential as a future treatment for retinal degeneration. However, there has been no such biodegradable material that could support the growth and maturation of hESC-RPE cells so far. The primary aim of this work was to create a thin porous poly (L-lactide-co-caprolactone) (PLCL) membrane that could promote attachment, proliferation, and maturation of the hESC-RPE cells in serum-free culture conditions. The PLCL membranes were modified by atmospheric pressure plasma processing and coated with collagen IV to enhance cell growth and maturation. Permeability of the membranes was analyzed with an Ussing chamber system. Analysis with scanning electron microscopy, contact angle measurement, atomic force microscopy, and X-ray photoelectron spectroscopy demonstrated that plasma surface treatment augments the surface properties of the membrane, which enhances the binding and conformation of the protein. Cell proliferation assays, reverse transcription-polymerase chain reaction, indirect immunofluoresence staining, trans-epithelial electrical resistance measurements, and in vitro phagocytosis assay clearly demonstrated that the plasma treated PLCL membranes supported the adherence, proliferation, maturation and functionality of hESC-RPE cells in serum-free culture conditions. Here, we report for the first time, how PLCL membranes can be modified with atmospheric pressure plasma processing to enable the formation of a functional hESC-RPE monolayer on a porous biodegradable substrate, which have a potential as a tissue-engineered construct for regenerative retinal repair applications.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Integrated Technologies for Tissue Engineering Research (ITTE), University of Ulster
Contributors: Sorkio, A., Porter, P. J., Juuti-Uusitalo, K., Meenan, B. J., Skottman, H., Burke, G. A.
Number of pages: 14
Pages: 2301-2314
Publication date: 1 Sep 2015
Peer-reviewed: Yes

Publication information

Journal: Tissue Engineering Part A
Volume: 21
Issue number: 17-18
ISSN (Print): 1937-3341
Ratings: 
  • Scopus rating (2015): CiteScore 7.3 SJR 1.536 SNIP 1.099
Original language: English
ASJC Scopus subject areas: Bioengineering, Biochemistry, Biomedical Engineering, Biomaterials, Medicine(all)
Source: Scopus
Source ID: 84940705576

Research output: Contribution to journalArticleScientificpeer-review

Influence of relative humidity and physical load during storage on dustiness of inorganic nanomaterials: implications for testing and risk assessment

Dustiness testing using a down-scaled EN15051 rotating drum was used to investigate the effects of storage conditions such as relative humidity and physical loading on the dustiness of five inorganic metal oxide nanostructured powder materials. The tests consisted of measurements of gravimetrical respirable dustiness index and particle size distributions. Water uptake of the powders during 7 days of incubation was investigated as an explanatory factor of the changes. Consequences of these varying storage conditions in exposure modelling were tested using the control banding and risk management tool NanoSafer. Drastic material-specific effects on powder respirable dustiness index were observed with the change in TiO<inf>2</inf> from 30 % RH (639 mg/kg) to 50 % RH (1.5 mg/kg). All five tested materials indicate a decreasing dustiness index with relative humidity increasing from 30 to 70 % RH. Test of powder water uptake showed an apparent link with the decreasing dustiness index. Effects of powder compaction appeared more material specific with both increasing and decreasing dustiness indices observed as an effect of compaction. Tests of control banding exposure models using the measured dustiness indices in three different exposure scenarios showed that in two of the tested materials, one 20 % change in RH changed the exposure banding from the lowest level to the highest. The study shows the importance of powder storage conditions prior to tests for classification of material dustiness indices. It also highlights the importance of correct storage information and relative humidity and expansion of the dustiness test conditions specifically, when using dustiness indices as a primary parameter for source strength in exposure assessment.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Materials Science, Research group: Materials Characterization, Engineering materials science and solutions (EMASS), Department of Micro and Nanotechnology, Denmark Technical University DTU, Finnish Institute of Occupational Health, CIC biomaGUNE, National Research Centre for the Working Environment
Contributors: Levin, M., Rojas, E., Vanhala, E., Vippola, M., Liguori, B., Kling, K. I.,