Multiresolution MAPEM method for 3D reconstruction of symmetrical particles with electron microscopy

The resolution and accuracy of the 3D images obtained with single particle reconstruction (SPR) highly depend on the number and signal to noise ratio of the particle images. The maximum a posteriori probability expectation maximization (MAPEM) reconstruction methods have been successful in suppressing noise and compensating for the limited angular sampling. This paper presents a multiresolution MAPEM (mMAPEM) method to improve the resolution and accuracy of the 3D images of the symmetrical particles reconstructed using SPR. The method utilizes the median root prior and the symmetry information about the reconstructed structure in the image domain. The method was compared with the conventional Fourier Reconstruction (FR) method using phantom and experimental datasets for different noise levels and projection angle sampling conditions. The numerical and visual assessment of the reconstruction results demonstrate that the mMAPEM method provides more accurate results than FR.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Signal Processing, Research group: M2oBSI, UC Davis
Contributors: Acar, E., Baikoghli, M. A., Stark, M., Peltonen, S., Ruotsalainen, U., Cheng, R. H.
Number of pages: 4
Pages: 141-144
Publication date: 2018

Host publication information

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

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: Electron microscopy, HEV, Multiresolution MAPEM reconstruction, Single particle reconstruction

Bibliographical note

jufoid=58152

Source: Scopus
Source ID: 85021754768

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

Enablers and barriers of smart data-based asset management services in industrial business networks

Recent academic research has paid particular attention to how digitalization disrupts current business models and business environments. Furthermore, servitization has gained significant attention. However, so far only a fraction of the wide range of opportunities related to digitalization has been realized. In this paper we aim to better understand the drivers, limitations and stakeholder expectations in different industrial business environments. In the proposed paper, we address digitalization in the area of engineering asset management from the following perspectives: (1) enablers and barriers of digitalized asset management service business, (2) availability and use of data for decision-making support, and (3) changes for business models. We also further contemplate which decision-making situations need to be supported by digital asset services. The paper is based on data received from a company workshop and a literature review.

General information

Publication status: Published
MoE publication type: A3 Part of a book or another research book
Organisations: Mechanical Engineering and Industrial Systems, Research area: Design, Development and LCM, VTT Technical Research Centre of Finland
Contributors: Ahonen, T., Hanski, J., Hyvärinen, M., Kortelainen, H., Uusitalo, T., Vainio, H., Kunttu, S., Koskinen, K.
Number of pages: 10
Pages: 51-60
Publication date: 2019

Host publication information

Title of host publication: Lecture Notes in Mechanical Engineering
Publisher: Pleiades Publishing

Publication series

Name: Lecture Notes in Mechanical Engineering
ISSN (Print): 2195-4356
ISSN (Electronic): 2195-4364
ASJC Scopus subject areas: Automotive Engineering, Aerospace Engineering, Mechanical Engineering, Fluid Flow and Transfer Processes

Bibliographical note

jufoid=79273

Source: Scopus
Source ID: 85056662614

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

Twelve years follow-up of ballistocardiography

The purpose of this work is to study the effect of long term alterations of ballistocardiography during 12 years time recorded in sitting position by using EMFi (Electromechanical Film) sensors. ECG, BCG, ankle pulse signal and carotid pulse (CP) signal from the neck near the carotid artery were recorded from a single person and duration of the signal components according to R spike of the ECG and amplitudes of the signals were studied. The time domain properties of BCG, CP and ankle pulse signals at different times (time interval around 1 year during 12 years time) remained rather stable within the same person. The BCG signal stability endured during 12 years time showing that no major changes happened in the condition of the heart-vasculature system.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Faculty of Biomedical Sciences and Engineering, Research group: Physiological Measurement Systems and Methods Group, BioMediTech, Tampere University of Applied Sciences (TAMK)
Contributors: Alametsä, J., Viik, J.
Number of pages: 4
Pages: 1117-1120
Publication date: 2018

Host publication information

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

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: BCG, Blood pressure, EMFi, Follow-up

Bibliographical note

jufoid=58152
EXT="Alametsä, J."

Source: Scopus
Source ID: 85021746269

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

Effects of nitroglycerin to ballistocardiography by EMFi

The purpose of this work was to study the effect of nitroglycerin (glyceryl trinitrate) to ballistocardiographic signal (BCG) recorded in sitting position by using Electromechanical Film (EMFi) sensors. ECG, BCG, ankle pulse signal and carotid pulse (CP) signal from the neck near the carotid artery were recorded from a single person and duration of the signal components according to R wave of the ECG and amplitudes of the signals were studied. In the first study the effect of 1 nitroglycerin pill was studied and in the second study the effect of exercise and the intake of 2 nitroglycerin pills were examined. The time domain properties of BCG, CP and ankle pulse signals stayed somewhat stable due to nitroglycerin intake. Noticeable increase was seen in some systolic signal amplitudes. Diastolic signal amplitudes mainly decreased. Signal traces became smoother and the fluctuation of the ballistic signals decreased. Nitroglycerin intake had a major but temporary effect on the heart-vasculature system due to increased aortic elasticity.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Faculty of Biomedical Sciences and Engineering, Tampere Uni. of Applied Sci.
Contributors: Alametsä, J., Viik, J.
Number of pages: 5
Pages: 541-545
Publication date: 2018

Host publication information

Title of host publication: World Congress on Medical Physics and Biomedical Engineering 2018
Volume: 2
Publisher: Springer
ISBN (Print): 978-981-10-9037-0
ISBN (Electronic): 978-981-10-9038-7

Publication series

Name: IFMBE Proceedings
Volume: 68
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Bioengineering, Biomedical Engineering
Keywords: Ballistocardiography, Nitro, Pulse wave

Bibliographical note

jufoid=58152
EXT="Alametsä, Jarmo"

Source: Scopus
Source ID: 85048209979

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

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

Screening ethnically diverse human embryonic stem cells identifies a chromosome 20 minimal amplicon conferring growth advantage

The International Stem Cell Initiative analyzed 125 human embryonic stem (ES) cell lines and 11 induced pluripotent stem (iPS) cell lines, from 38 laboratories worldwide, for genetic changes occurring during culture. Most lines were analyzed at an early and late passage. Single-nucleotide polymorphism (SNP) analysis revealed that they included representatives of most major ethnic groups. Most lines remained karyotypically normal, but there was a progressive tendency to acquire changes on prolonged culture, commonly affecting chromosomes 1, 12, 17 and 20. DNA methylation patterns changed haphazardly with no link to time in culture. Structural variants, determined from the SNP arrays, also appeared sporadically. No common variants related to culture were observed on chromosomes 1, 12 and 17, but a minimal amplicon in chromosome 20q11.21, including three genes expressed in human ES cells, ID1, BCL2L1 and HM13, occurred in >20% of the lines. Of these genes, BCL2L1 is a strong candidate for driving culture adaptation of ES cells.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Integrated Technologies for Tissue Engineering Research (ITTE), University of Sheffield, International Centre for Life, A-STAR, Immunos, Royan Institute, mediaX and H*STAR Stanford University Stanford, Sheffield Children's NHS Trust, University of Nottingham, Keck School of Medicine of USC, Hebrew University of Jerusalem, Tel Aviv University, Sackler Faculty of Medicine, Cedars-Sinai Medical Institute, University of Geneva, Manchester Academic Health Sciences Centre, Cellartis AB, University of Manchester, Genome Institute of Singapore, Hoffmann-LaRoche, Seoul National University College of Medicine, Bioprocessing Technology Institute, Roslin Cells Ltd., University of Melbourne, Harvard Stem Cell Institute, University of Edinburgh, Masaryk University, WiCell Research Institute, Hopital Cantonal Fribourgois, Department of Applied Physics, Lis Maternity Hospital Israel, Central South University China, Hadassah University Medical Center, Institute of Experimental Botany of the Academy of Sciences of the Czech Republic, University College London, National Institute for Biological Standards and Control, Karolinska University Hospital, Jawaharlal Nehru Centre for Advanced Scientific Research, NYU Langone Medical Center, Shanghai Jiaotong University, Vavilov Institute of General Genetics, Reproductive Genetics Institute, Monash University, CHA University, Vrije Universiteit Brussel, Mount Sinai Hospital, GE Healthcare, UK, Kyoto Women's University, Leiden University Medical Center - LUMC, University of Helsinki, Yale School of Medicine, Viacyte, Hospital for Sick Children University of Toronto, University of New South Wales (UNSW) Australia, Gladstone Institute of Cardiovascular Disease, CSIRO Energy Centre
Contributors: Amps, K., Andrews, P. W., Anyfantis, G., Armstrong, L., Avery, S., Baharvand, H., Baker, J., Baker, D., Munoz, M. B., Beil, S., Benvenisty, N., Ben-Yosef, D., Biancotti, J. C., Bosman, A., Brena, R. M., Brison, D., Caisander, G., Camarasa, M. V., Chen, J., Chiao, E., Choi, Y. M., Choo, A. B. H., Collins, D., Colman, A., Crook, J. M., Daley, G. Q., Dalton, A., De Sousa, P. A., Denning, C., Downie, J., Dvorak, P., Montgomery, K. D., Feki, A., Ford, A., Fox, V., Fraga, A. M., Frumkin, T., Ge, L., Gokhale, P. J., Golan-Lev, T., Gourabi, H., Gropp, M., Guangxiu, L., Hampl, A., Harron, K., Healy, L., Herath, W., Holm, F., Hovatta, O., Hyllner, J., Inamdar, M. S., Irwanto, A. K., Ishii, T., Jaconi, M., Jin, Y., Kimber, S., Kiselev, S., Knowles, B. B., Kopper, O., Kukharenko, V., Kuliev, A., Lagarkova, M. A., Laird, P. W., Lako, M., Laslett, A. L., Lavon, N., Lee, D. R., Lee, J. E., Li, C., Lim, L. S., Ludwig, T. E., Ma, Y., Maltby, E., Mateizel, I., Mayshar, Y., Mileikovsky, M., Minger, S. L., Miyazaki, T., Moon, S. Y., Moore, H., Mummery, C., Nagy, A., Nakatsuji, N., Narwani, K., Oh, S. K. W., Oh, S. K., Olson, C., Otonkoski, T., Pan, F., Park, I. H., Pells, S., Pera, M. F., Pereira, L. V., Qi, O., Raj, G. S., Reubinoff, B., Robins, A., Robson, P., Rossant, J., Salekdeh, G. H., Schulz, T. C., Sermon, K., Mohamed, J. S., Shen, H., Sherrer, E., Sidhu, K., Sivarajah, S., Skottman, H., Spits, C., Stacey, G. N., Strehl, R., Strelchenko, N., Suemori, H., Sun, B., Suuronen, R., Takahashi, K., Tuuri, T., Venu, P., Verlinsky, Y., Oostwaard, D. W. V., Weisenberger, D. J., Wu, Y., Yamanaka, S., Young, L., Zhou, Q.
Number of pages: 13
Pages: 1132-1144
Publication date: Dec 2011
Peer-reviewed: Yes

Publication information

Journal: Nature Biotechnology
Volume: 29
Issue number: 12
ISSN (Print): 1087-0156
Ratings: 
  • Scopus rating (2011): CiteScore 38.7 SJR 11.749 SNIP 6.125
Original language: English
ASJC Scopus subject areas: Biotechnology, Bioengineering, Medicine(all), Molecular Medicine, Biomedical Engineering, Applied Microbiology and Biotechnology
Source: Scopus
Source ID: 83255189758

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

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

Applications of nanocellulose/nanocarbon composites: Focus on biotechnology and medicine

Nanocellulose/nanocarbon composites are newly emerging smart hybrid materials containing cellulose nanoparticles, such as nanofibrils and nanocrystals, and carbon nanoparticles, such as “classical” carbon allotropes (fullerenes, graphene, nanotubes and nanodiamonds), or other carbon nanostructures (carbon nanofibers, carbon quantum dots, activated carbon and carbon black). The nanocellulose component acts as a dispersing agent and homogeneously distributes the carbon nanoparticles in an aqueous environment. Nanocellulose/nanocarbon composites can be prepared with many advantageous properties, such as high mechanical strength, flexibility, stretchability, tunable thermal and electrical conductivity, tunable optical transparency, photodynamic and photothermal activity, nanoporous character and high adsorption capacity. They are therefore promising for a wide range of industrial applications, such as energy generation, storage and conversion, water purification, food packaging, construction of fire retardants and shape memory devices. They also hold great promise for biomedical applications, such as radical scavenging, photodynamic and photothermal therapy of tumors and microbial infections, drug delivery, biosensorics, isolation of various biomolecules, electrical stimulation of damaged tissues (e.g., cardiac, neural), neural and bone tissue engineering, engineering of blood vessels and advanced wound dressing, e.g., with antimicrobial and antitumor activity. However, the potential cytotoxicity and immunogenicity of the composites and their components must also be taken into account.

General information

Publication status: Published
MoE publication type: A2 Review article in a scientific journal
Organisations: BioMediTech, Research group: Micro and Nanosystems Research Group, Automation Technology and Mechanical Engineering, Research group: Plastics and Elastomer Technology, Institute of Physiology of the Czech Academy of Sciences, Slovak University of Agriculture in Nitra
Contributors: Bacakova, L., Pajorova, J., Tomkova, M., Matejka, R., Broz, A., Stepanovska, J., Prazak, S., Skogberg, A., Siljander, S., Kallio, P.
Number of pages: 32
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: Nanomaterials
Volume: 10
Issue number: 2
Article number: 196
ISSN (Print): 2079-4991
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Materials Science(all)
Keywords: Carbon nanotubes, Cellulose nanocrystals, Diamond nanoparticles, Drug delivery, Fullerenes, Graphene, Nanofibrillated cellulose, Sensors, Tissue engineering, Wound dressing
Source: Scopus
Source ID: 85078449208

Research output: Contribution to journalReview ArticleScientificpeer-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

Moving Web and Dynamic Problem of Aerothermoelastic Vibrations and Instability

The paper is devoted to the analysis of the axially travelling web supported by a system of fixed rollers and submerged in axially flowing gas medium. In order to accurately model the dynamics and stability of a lightweight moving web, the interaction between it and the surrounding air is taken into account. The light weight of the moving web leads to the inertial contribution of the surrounding air to the acceleration of the material becoming significant. In the context of this paper we apply a Galerkin method for dynamic stability analysis of the moving web based on developed added-mass model.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Civil Engineering, Research group: Electromechanics, Russian Acad Sci, Russian Academy of Sciences, Kotelnikov Inst Radio Engn & Elect
Contributors: Banichuk, N., Ivanova, S., Jeronen, J.
Number of pages: 6
Pages: 66-71
Publication date: 2020

Host publication information

Title of host publication: Advanced Problems in Mechanics : Proceedings of the 47th International Summer School-Conference on Advanced Problems in Mechanics, APM 2019
Publisher: Springer
Editors: Indeitsev, D., Krivtsov, A.
ISBN (Print): 9783030498818
ISBN (Electronic): 978-3-030-49882-5

Publication series

Name: Lecture Notes in Mechanical Engineering
ISSN (Print): 2195-4356
ISSN (Electronic): 2195-4364
ASJC Scopus subject areas: Automotive Engineering, Aerospace Engineering, Mechanical Engineering, Fluid Flow and Transfer Processes
Keywords: Aeroelastic vibrations, Instability, Moving web

Bibliographical note

JUFOID=79273

Source: Scopus
Source ID: 85090672412

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

Nanostructured Ionomeric Elastomers

Driven by the desire to find an alternative way of vulcanizing elastomers without sulfur, researchers have widely explored ionic crosslinking techniques. The opportunity was taken to play with the functionality of the host polymer and its modification process to develop nanostructured ionic elastomers. Neutralization of polar elastomers by various divalent metal cations has been the route most employed for fabrication of this class of material. Ionic association or aggregation on the molecular level results in microphase separation of certain regions and, hence, enables easier processing. Thermally labile ionic domains introduced into the network make the entire material thermoresponsive and, therefore, it is possible to obtain reversible transition of dynamic mechanical properties. The unique network structure of these materials has led to outstanding physical properties that have not been achieved so far for conventional sulfidic networks. Consequently, many multifunctional and smart materials have been envisaged and designed using these systems. A detailed overview is provided on the various nanostructured ionic elastomers developed over the years. It would not be exaggerating to mention in the context of the discussion that nanostructured ionic elastomers will definitely open up new horizons in materials research.

General information

Publication status: Published
MoE publication type: A3 Part of a book or another research book
Organisations: Department of Materials Science, Research group: Plastics and Elastomer Technology, Apollo Tyres Limited, Leibniz-Institut für Polymerforschung Dresden E.V., Vodafone Department of Mobile Communications Systems
Contributors: Basu, D., Das, A., Stöckelhuber, K. W., Wießner, S.
Number of pages: 32
Pages: 235-266
Publication date: 17 Aug 2016

Host publication information

Title of host publication: Designing of Elastomer Nanocomposites: From Theory to Applications
Publisher: Springer International Publishing
Editors: Stöckelhuber, K. W., Das, A., Klüppel, M.
ISBN (Print): 9783319476957
ISBN (Electronic): 9783319476964

Publication series

Name: Advances in Polymer Science
Volume: 275
ISSN (Print): 0065-3195
ASJC Scopus subject areas: Chemical Engineering(all), Polymers and Plastics, Organic Chemistry
Keywords: Elastomers, Ionic crosslinking, Self healing rubber

Bibliographical note

JUFOID=50551

Source: Scopus
Source ID: 84994670333

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

Second-harmonic generation imaging of semiconductor nanowires with focused vector beams

We use second-harmonic generation (SHG) with focused vector beams to investigate individual vertically aligned GaAs nanowires. Our results provide direct evidence that SHG from oriented nanowires is mainly driven by the longitudinal field along the nanowire growth axis. Consequently, focused radial polarization provides a superior tool to characterize such nanowires compared to linear polarization, also allowing this possibility in the native growth environment. We model our experiments by describing the SHG process for zinc-blende structure and dipolar bulk nonlinearity.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Physics, Research area: Optics, Research group: Nonlinear Optics, Tampere University of Technology, Frontier Photonics, Aalto University, Department of Micro- and Nanosciences, Aalto University, Department of Applied Physics and Nanomicroscopy Center
Contributors: Bautista, G., Mäkitalo, J., Chen, Y., Dhaka, V., Grasso, M., Karvonen, L., Jiang, H., Huttunen, M. J., Huhtio, T., Lipsanen, H., Kauranen, M.
Number of pages: 6
Pages: 1564-1569
Publication date: 6 Feb 2015
Peer-reviewed: Yes

Publication information

Journal: Nano Letters
Volume: 15
Issue number: 3
ISSN (Print): 1530-6984
Ratings: 
  • Scopus rating (2015): CiteScore 22.9 SJR 8.359 SNIP 3.071
Original language: English
ASJC Scopus subject areas: Condensed Matter Physics, Bioengineering, Chemistry(all), Materials Science(all), Mechanical Engineering
Keywords: modeling, nonlinear imaging, radial polarization, Second-harmonic generation, semiconductor

Bibliographical note

AUX=fys,"Grasso, Marco"
EXT="Dhaka, Veer"
EXT="Huttunen, Mikko J."

Source: Scopus
Source ID: 84924595561

Research output: Contribution to journalArticleScientificpeer-review

Screening pretreatment methods to enhance thermophilic anaerobic digestion of pulp and paper mill wastewater treatment secondary sludge

The effect of hydrothermal (150°C for 10min and 70°C for 40min), enzymatic (Accelerase 1500, 0.07g/g volatile solids (VS)), ultrasound (45kHz for 30min) and chemical pretreatments (HNO3 at pH3 and NaOH at pH12) alone or in combination on the chemical composition and methane yield of the pulp and paper mill secondary sludge was studied in batch assays at 55°C. In total, 12 different pretreatment combinations were compared. Chemical analyses showed that all pretreatments except for HNO3 and ultrasound pretreatments improved the organic matter solubilization. Among the studied pretreatments, hydrothermal (150°C, 10min) pretreatment alone or in combination with enzymatic and/or ultrasound pretreatment had the highest impact on sludge solubilization and methane yield. The increase in methane yield was 31% (from 108ml/g VSoriginal to 141ml/gVSoriginal). In addition, enzymatic pretreatment also improved the methane yields but only when combined with hydrothermal pretreatment at 150°C or ultrasound+hydrothermal pretreatment at 150°C. On the other hand, ultrasound pretreatment did not improve the methane yields while acid and alkaline pretreatments resulted in lower methane yields than control. Improved hydrolysis and higher methane production rates noticed in assays subjected to hydrothermal pretreatment alone or in combination with enzymes and/or ultrasound could make these treatments more attractive in reducing the retention times required during full-scale anaerobic digestion of pulp and paper mill wastewater sludges. © 2013 Elsevier B.V.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Tampere University of Technology, Department of Chemistry and Bioengineering, Urban circular bioeconomy (UrCirBio), Jyväskylän yliopisto, University of Jyväskylä
Contributors: Bayr, S., Kaparaju, P., Rintala, J.
Number of pages: 8
Pages: 479-486
Publication date: 1 May 2013
Peer-reviewed: Yes

Publication information

Journal: Chemical Engineering Journal
Volume: 223
ISSN (Print): 1385-8947
Ratings: 
  • Scopus rating (2013): CiteScore 6.2 SJR 1.597 SNIP 1.908
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Chemistry(all), Industrial and Manufacturing Engineering, Environmental Chemistry
Keywords: Anaerobic digestion, Methane yield, Pretreatment, Pulp and paper mill, Secondary sludge

Bibliographical note

Contribution: organisation=keb,FACT1=1<br/>Portfolio EDEND: 2013-11-29<br/>Publisher name: Elsevier BV

Source: researchoutputwizard
Source ID: 1974

Research output: Contribution to journalArticleScientificpeer-review

Multifunctional ultrasmall nanoplatforms for vascular-targeted interstitial photodynamic therapy of brain tumors guided by real-time MRI

Photodynamic therapy (PDT) for brain tumors appears to be complementary to conventional treatments. A number of studies show the major role of the vascular effect in the tumor eradication by PDT. For interstitial PDT (iPDT) of brain tumors guided by real-time imaging, multifunctional nanoparticles consisting of a surface-localized tumor vasculature targeting neuropilin-1 (NRP-1) peptide and encapsulated photosensitizer and magnetic resonance imaging (MRI) contrast agents, have been designed. Nanoplatforms confer photosensitivity to cells and demonstrate a molecular affinity to NRP-1. Intravenous injection into rats bearing intracranial glioma exhibited a dynamic contrast-enhanced MRI for angiogenic endothelial cells lining the neovessels mainly located in the peripheral tumor. By using MRI completed by NRP-1 protein expression of the tumor and brain adjacent to tumor tissues, we checked the selectivity of the nanoparticles. This study represents the first in vivo proof of concept of closed-head iPDT guided by real-time MRI using targeted ultrasmall nanoplatforms.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Frontier Photonics, Université de Lorraine, Lille University Hospital - CHRU, Marcilly-sur-Eure, CHU de Nancy, Claude Bernard-University
Contributors: Bechet, D., Auger, F., Couleaud, P., Marty, E., Ravasi, L., Durieux, N., Bonnet, C., Plénat, F., Frochot, C., Mordon, S., Tillement, O., Vanderesse, R., Lux, F., Perriat, P., Guillemin, F., Barberi-Heyob, M.
Number of pages: 14
Pages: 657-670
Publication date: 2015
Peer-reviewed: Yes

Publication information

Journal: NANOMEDICINE: NANOTECHNOLOGY BIOLOGY AND MEDICINE
Volume: 11
Issue number: 3
ISSN (Print): 1549-9634
Ratings: 
  • Scopus rating (2015): CiteScore 11.4 SJR 1.857 SNIP 1.69
Original language: English
ASJC Scopus subject areas: Molecular Medicine, Bioengineering, Biomedical Engineering, Materials Science(all), Medicine (miscellaneous), Pharmaceutical Science, Medicine(all)
Keywords: Brain tumor, iPDT, Multifunctional nanoplatforms, Real-time MRI, Targeting
Source: Scopus
Source ID: 84933510120

Research output: Contribution to journalArticleScientificpeer-review

Optical projection tomography imaging of single cells in 3D gellan gum hydrogel

3D cell culturing has become attractive in biology and tissue engineering laboratories as it mimics the natural environment for the cells to grow, differentiate and interact in all directions. To study cells and cellular interactions within 3D, cell culture requires a non-invasive, non-toxic, and high resolution imaging technique. The existing imaging techniques face challenges to image cells in 3D macro-scale environment because of the sample size, photo-bleaching or resolution requirements. Optical projection tomography (OPT) is a non-invasive 3D imaging technique for samples in the range of 1-10 mm. It works in both emission and transmission modes for fluorescence and bright-field imaging, respectively. Here, we demonstrate the use of OPT for imaging of cells and cellular materials in 3D gellan gum hydrogel. Fluorescence projection images showed alive and dead human lung fibroblast cells encapsulated in hydrogel. The mineralized extracellular matrix secreted by the human adipose stem cells in the hydrogel was evenly distributed throughout the sample and analyzable in 3D volume.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Faculty of Biomedical Sciences and Engineering, Research group: Computational Biophysics and Imaging Group, Research group: Biomaterials and Tissue Engineering Group, BioMediTech, International Iberian Nanotechnology Laboratory, BioMediTech Institute and Faculty of Medicine and Life Sciences
Contributors: Belay, B., Koivisto, J. T., Vuornos, K., Montonen, T., Koskela, O., Lehti-Polojärvi, M., Miettinen, S., Kellomäki, M., Figueiras, E., Hyttinen, J.
Number of pages: 4
Pages: 996-999
Publication date: 2018

Host publication information

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

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: 3D imaging, Fluorescence, Hydrogel, Mesenchymal cell culture, Optical projection tomography
Electronic versions: 

Bibliographical note

jufoid=58152
EXT="Vuornos, K."

Source: Scopus
Source ID: 85021747989

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

Waves in hyperbolic and double negative metamaterials including rogues and solitons

The topics here deal with some current progress in electromagnetic wave propagation in a family of substances known as metamaterials. To begin with, it is discussed how a pulse can develop a leading edge that steepens and it is emphasised that such self-steepening is an important inclusion within a metamaterial environment together with Raman scattering and third-order dispersion whenever very short pulses are being investigated. It is emphasised that the self-steepening parameter is highly metamaterial-driven compared to Raman scattering, which is associated with a coefficient of the same form whether a normal positive phase, or a metamaterial waveguide is the vehicle for any soliton propagation. It is also shown that the influence of magnetooptics provides a beautiful and important control mechanism for metamaterial devices and that, in the future, this feature will have a significant impact upon the design of data control systems for optical computing. A major objective is fulfiled by the investigations of the fascinating properties of hyperbolic media that exhibit asymmetry of supported modes due to the tilt of optical axes. This is a topic that really merits elaboration because structural and optical asymmetry in optical components that end up manipulating electromagnetic waves is now the foundation of how to operate some of the most successful devices in photonics and electronics. It is pointed out, in this context, that graphene is one of the most famous plasmonic media with very low losses. It is a two-dimensional material that makes the implementation of an effective-medium approximation more feasible. Nonlinear non-stationary diffraction in active planar anisotropic hyperbolic metamaterials is discussed in detail and two approaches are compared. One of them is based on the averaging over a unit cell, while the other one does not include sort of averaging. The formation and propagation of optical spatial solitons in hyperbolic metamaterials is also considered with a model of the response of hyperbolic metamaterials in terms of the homogenisation ('effective medium') approach. The model has a macroscopic dielectric tensor encompassing at least one negative eigenvalue. It is shown that light propagating in the presence of hyperbolic dispersion undergoes negative (anomalous) diffraction. The theory is ten broadened out to include the influence of the orientation of the optical axis with respect to the propagation wave vector. Optical rogue waves are discussed in terms of how they are influenced, but not suppressed, by a metamaterial background. It is strongly discussed that metamaterials and optical rogue waves have both been making headlines in recent years and that they are, separately, large areas of research to study. A brief background of the inevitable linkage of them is considered and important new possibilities are discussed. After this background is revealed some new rogue wave configurations combining the two areas are presented alongside a discussion of the way forward for the future.

General information

Publication status: Published
MoE publication type: A2 Review article in a scientific journal
Organisations: Photonics, University of Salford, Sapienza University, IICBA, UMR 6174, Original Perspectives Ltd, Aalto University, ITMO University, Taras Shevchenko National University of Kyiv, Nazarbayev University
Contributors: Boardman, A. D., Alberucci, A., Assanto, G., Grimalsky, V. V., Kibler, B., McNiff, J., Nefedov, I. S., Rapoport, Y. G., Valagiannopoulos, C. A.
Publication date: 9 Oct 2017
Peer-reviewed: Yes

Publication information

Journal: Nanotechnology
Volume: 28
Issue number: 44
Article number: 444001
ISSN (Print): 0957-4484
Ratings: 
  • Scopus rating (2017): CiteScore 5.2 SJR 1.079 SNIP 0.885
Original language: English
ASJC Scopus subject areas: Bioengineering, Chemistry(all), Materials Science(all), Mechanics of Materials, Mechanical Engineering, Electrical and Electronic Engineering
Keywords: rogues, solitons, waves
Source: Scopus
Source ID: 85032180863

Research output: Contribution to journalReview ArticleScientificpeer-review

The sensitivity of random polymer brush-lamellar polystyrene-b-polymethylmethacrylate block copolymer systems to process conditions

The use of random copolymer brushes (polystyrene- r-polymethylmethacrylate - PS- r-PMMA) to 'neutralise' substrate surfaces and ordain perpendicular orientation of the microphase separated lamellae in symmetric polystyrene- b-polymethylmethacrylate (PS- b-PMMA) block copolymers (BCPs) is well known. However, less well known is how the brushes interact with both the substrate and the BCP, and how this might change during thermal processing. A detailed study of changes in these films for different brush and diblock PS- b-PMMA molecular weights is reported here. In general, self-assembly and pattern formation is altered little, and a range of brush molecular weights are seen to be effective. However, on extended anneal times, the microphase separated films can undergo dimension changes and loss of order. This process is not related to any complex microphase separation dynamics but rather a degradation of methacrylate components in the film. The data suggest that care must be taken in interpretation of structural changes in these systems as being due to BCP only effects.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Frontier Photonics, Tyndall National Institute at National University of Ireland, Cork, Materials Chemistry and Analysis Group, University College Cork, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Leixlip Co.
Contributors: Borah, D., Rasappa, S., Senthamaraikannan, R., Shaw, M. T., Holmes, J. D., Morris, M. A.
Number of pages: 11
Pages: 192-202
Publication date: 1 Mar 2013
Peer-reviewed: Yes

Publication information

Journal: Journal of Colloid and Interface Science
Volume: 393
Issue number: 1
ISSN (Print): 0021-9797
Ratings: 
  • Scopus rating (2013): CiteScore 6.1 SJR 1.195 SNIP 1.437
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Biomaterials, Surfaces, Coatings and Films, Colloid and Surface Chemistry
Keywords: Microphase separation, Polymer brush, Polystyrene-b-polymethylmethacrylate, Polystyrene-r-polymethylmethacrylate, Surface morphology
Source: Scopus
Source ID: 84873060382

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

Synthesis of depsipeptides from L-amino acids and lactones

By using the corresponding L-amino acid sodium as initiator, e{open}-caprolactone-depsipeptides CL-Ala and CL-Leu were prepared by the reactions of e{open}-caprolactone (CL) with L-alanine and L-leucine, respectively, and p-dioxanone-depsipeptide (PDO-Leu) was prepared by the reaction of p-dioxanone (PDO) with L leucine. Two poly(e{open}-caprolactone) oligomers (PCL-Ala and PCL-Leu) of different molecular weights with depsipeptide unit were synthesized by controlling the feed ratio of L-amino acid sodium and CL. The presence of the depsipeptide structure in these obtained products was confirmed by 1H NMR spectra and the molecular weight of the poly(e{open}-caprolactone) oligomers was measured by gel permeation chromatography (GPC). These products contain a hydroxyl group and a carboxyl group in one molecule, which means they could act as bifunctional monomers for further polymerization to prepare high molecular weight polymers. By this way, the depsipeptide unit could be introduced into the polymers and the biodegradation rates of the novel polymers could be well controlled in vivo by the tailored molecular structures.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Integrated Technologies for Tissue Engineering Research (ITTE), Tianjin University, School of Chemical Engineering and Technology
Contributors: Cao, H., Feng, Y., Wang, H., Zhang, L., Khan, M., Guo, J.
Number of pages: 7
Pages: 409-415
Publication date: Dec 2011
Peer-reviewed: Yes

Publication information

Journal: Frontiers of Chemical Science and Engineering
Volume: 5
Issue number: 4
ISSN (Print): 2095-0179
Ratings: 
  • Scopus rating (2011): CiteScore 0.7 SJR 0.23 SNIP 0.35
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all)
Keywords: e{open}-caprolactone, L-alanine, L-leucine depsipeptide, p-dioxanone
Source: Scopus
Source ID: 83355176163

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

Electricity production by a microbial fuel cell fueled by brewery wastewater and the factors in its membrane deterioration

Electricity production from brewery wastewater using dual-chamber microbial fuel cells (MFCs) with a tin-coated copper mesh in the anode was investigated by changing the hydraulic retention time (HRT). The MFCs were fed with wastewater samples from the inlet (inflow, MFC-1) and outlet (outflow, MFC-2) of an anaerobic digester of a brewery wastewater treatment plant. Both chemical oxygen demand removal and current density were improved by decreasing HRT. The best MFC performance was with an HRT of 0.5 d. The maximum power densities of 8.001 and 1.843 µW/cm<sup>2</sup> were obtained from reactors MFC-1 and MFC-2, respectively. Microbial diversity at different conditions was studied using PCR-DGGE profiling of 16S rRNA fragments of the microorganisms from the biofilm on the anode electrode. The MFC reactor had mainly Geobacter, Shewanella, and Clostridium species, and some bacteria were easily washed out at lower HRTs. The fouling characteristics of the MFC Nafion membrane and the resulting degradation of MFC performance were examined. The ion exchange capacity, conductivity, and diffusivity of the membrane decreased significantly after fouling. The morphology of the Nafion membrane and MFC degradation were studied using scanning electron microscopy and attenuated total reflection-Fourier transform infrared spectroscopy.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Portland State University, Department of Civil and Environmental Engineering, Yildiz Technical University
Contributors: Çetinkaya, A. Y., Köroğlu, E. O., Demir, N. M., Baysoy, D. Y., Özkaya, B., Çakmakçi, M.
Number of pages: 9
Pages: 1068-1076
Publication date: 20 Jul 2015
Peer-reviewed: Yes

Publication information

Journal: Chinese Journal of Catalysis
Volume: 36
Issue number: 7
ISSN (Print): 0253-9837
Ratings: 
  • Scopus rating (2015): CiteScore 3.4 SJR 0.579 SNIP 0.805
Original language: English
ASJC Scopus subject areas: Catalysis, Chemistry(all)
Keywords: Anaerobic processe, Biofilm, Microbial community, Microbial fuel cell, Wastewater treatment

Bibliographical note

EXT="Çakmakçi, Mehmet"

Source: Scopus
Source ID: 84934932934

Research output: Contribution to journalArticleScientificpeer-review

Evaluating different shapes of cranial fixation mini-plates using finite element method

Medical grade 3D printing offers the possibility to manufacture patient-specific implants to treat cranial defects. The performance of the implant assembly depends on many factors, such as material, thickness, size and manufacturing accuracy. A significant factor in the stability and success of the assembly is the fixation method. Cranial implants are usually fixed to the skull by means of mini-plates. Biomechanical assessment of fixing the implant to the skull might be helpful not only for mini-plate design but might be beneficial also for the surgeons. In this study, four different mini-plate designs were analyzed and compared based on the stress-strain analysis of one cranial implant fixed at three locations by mini-plates. Computational simulations were done using Finite Element Method.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Faculty of Biomedical Sciences and Engineering, Research group: Computational Biophysics and Imaging Group, BioMediTech, Brno University of Technology
Contributors: Chamrad, J., Marcián, P., Narra, N., Borák, L.
Number of pages: 4
Pages: 747-750
Publication date: 2018

Host publication information

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

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: Cranial implants, FEA, Fixation mini-plates, Polymethyl methacrylate, Stress-strain analysis

Bibliographical note

jufoid=58152

Source: Scopus
Source ID: 85021704982

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

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

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

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

Assessment of metabolic flux distribution in the thermophilic hydrogen producer Caloramator celer as affected by external pH and hydrogen partial pressure

Background: Caloramator celer is a strict anaerobic, alkalitolerant, thermophilic bacterium capable of converting glucose to hydrogen (H2), carbon dioxide, acetate, ethanol and formate by a mixed acid fermentation. Depending on the growth conditions C. celer can produce H2 at high yields. For a biotechnological exploitation of this bacterium for H2 production it is crucial to understand the factors that regulate carbon and electron fluxes and therefore the final distribution of metabolites to channel the metabolic flux towards the desired product.Results: Combining experimental results from batch fermentations with genome analysis, reconstruction of central carbon metabolism and metabolic flux analysis (MFA), this study shed light on glucose catabolism of the thermophilic alkalitolerant bacterium C. celer. Two innate factors pertaining to culture conditions have been identified to significantly affect the metabolic flux distribution: culture pH and partial pressures of H2 (PH2). Overall, at alkaline to neutral pH the rate of biomass synthesis was maximized, whereas at acidic pH the lower growth rate and the less efficient biomass formation are accompanied with more efficient energy recovery from the substrate indicating high cell maintenance possibly to sustain intracellular pH homeostasis. Higher H2 yields were associated with fermentation at acidic pH as a consequence of the lower synthesis of other reduced by-products such as formate and ethanol. In contrast, PH2 did not affect the growth of C. celer on glucose. At high PH2 the cellular redox state was balanced by rerouting the flow of carbon and electrons to ethanol and formate production allowing unaltered glycolytic flux and growth rate, but resulting in a decreased H2 synthesis.Conclusion: C. celer possesses a flexible fermentative metabolism that allows redistribution of fluxes at key metabolic nodes to simultaneously control redox state and efficiently harvest energy from substrate even under unfavorable conditions (i.e. low pH and high PH2). With the H2 production in mind, acidic pH and low PH2 should be preferred for a high yield-oriented process, while a high productivity-oriented process can be achieved at alkaline pH and high PH2. © 2014 Ciranna et al.; licensee BioMed Central Ltd.

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, Tampere University of Technology, Urban circular bioeconomy (UrCirBio), Lunds Universitet / Lunds Tekniska Högskola, Lund Univ, Lund University, Department of Applied Microbiology
Contributors: Ciranna, A., Pawar, S. S., Santala, V., Karp, M., van Niel, E. W. J.
Publication date: 28 Mar 2014
Peer-reviewed: Yes

Publication information

Journal: Microbial Cell Factories
Volume: 13
Issue number: 1
Article number: 48
ISSN (Print): 1475-2859
Ratings: 
  • Scopus rating (2014): CiteScore 7 SJR 1.757 SNIP 1.508
Original language: English
ASJC Scopus subject areas: Biotechnology, Bioengineering, Applied Microbiology and Biotechnology
Keywords: Biohydrogen production, Caloramator, Ethanol, Fermentation, Formate, Hydrogen tolerance, Metabolic flux analysis, Metabolic shift, Pyruvate node, Redox state

Bibliographical note

Contribution: organisation=keb,FACT1=1<br/>Portfolio EDEND: 2014-04-29<br/>Publisher name: BioMed Central Ltd.

Source: researchoutputwizard
Source ID: 236

Research output: Contribution to journalArticleScientificpeer-review

Second-Harmonic Generation from Metal Nanoparticles: Resonance Enhancement versus Particle Geometry

We demonstrate that optical second-harmonic generation (SHG) from arrays of noncentrosymmetric gold nanoparticles depends essentially on particle geometry. We prepare nanoparticles with different geometrical shapes (L and T) but similar wavelengths for the polarization-dependent plasmon resonances. In contrast to recent interpretations emphasizing resonances at the fundamental frequency, the T shape leads to stronger SHG when only one, instead of both, polarization component of the fundamental field is resonant. This is explained by the character of plasmon oscillations supported by the two shapes. Our numerical simulations for both linear and second-order responses display unprecedented agreement with measurements.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Physics, Research area: Optics, Research group: Nonlinear Optics, Frontier Photonics, Institute of Photonics, Univ Eastern Finland, University of Eastern Finland, Sch Pharm
Contributors: Czaplicki, R., Mäkitalo, J., Siikanen, R., Husu, H., Lehtolahti, J., Kuittinen, M., Kauranen, M.
Number of pages: 5
Pages: 530-534
Publication date: 14 Jan 2015
Peer-reviewed: Yes
Early online date: 18 Dec 2014

Publication information

Journal: Nano Letters
Volume: 15
Issue number: 1
ISSN (Print): 1530-6984
Ratings: 
  • Scopus rating (2015): CiteScore 22.9 SJR 8.359 SNIP 3.071
Original language: English
ASJC Scopus subject areas: Condensed Matter Physics, Bioengineering, Chemistry(all), Materials Science(all), Mechanical Engineering
Keywords: Metal nanoparticles, nonlinear optics, plasmonic resonances, second-harmonic generation
Source: WOS
Source ID: 000348086100083

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

Osteoconductive properties of poly(96L/4D-lactide)/beta-tricalcium phosphate in long term animal model

The objective of this study was to determine the effect of calcium phosphate mineral content on the bone in-growth at the expense of composite of co-polylactide polymer charged with 2 different ratios of β-TCP granules (10 and 24 w-% of β-TCP). The evaluation was realized in a long term rabbit bone model. After 24, 48 and 76 weeks, the implants were examined by micro CT, scanning electron microscopy (SEM) using backscattered electron (BSE) and light microscopy (polarized and blue light microscopy). No foreign body reaction was detected during the 76 weeks follow-up in any of the test samples. Polymer hydrolysis began at approximately 24 weeks, by 76 weeks, the pure polymer implant had begun to release P(96L/4D)LA particles and show signs of peripheral localized bone resorption. A decrease in the amount of CaP was noticed between 24 and 76 weeks in both 10 wt-% and 24 wt-% β-TCP/P(96L/4D)LA composites. The study showed that the highest bone in-growth was with 24 wt-% β-TCP/P(96L/4D)LA composite. Bone in-growth and mineralization were evident for the composites associated with specific peripheral bone architecture. Fluorescent labelling demonstrated high bone in-growth and remodeling at the interface, while for pure co-polymer no bone remodeling or bone activity was maintained after 48 weeks. The study demonstrated the positive effect of calcium phosphate content into P(96L/4D)LA. This kind of composite is a suitable resorbable osteoconductive matrix, which provides long term stability required for ligament fixation device.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Engineering materials science and solutions (EMASS), PTIB Hôpital Xavier Arnozan, National Veterinary School of Nantes, Conmed Linvatec Biomaterials Ltd.
Contributors: Daculsi, G., Goyenvalle, E., Cognet, R., Aguado, E., Suokas, E. O.
Number of pages: 12
Pages: 3166-3177
Publication date: Apr 2011
Peer-reviewed: Yes

Publication information

Journal: Biomaterials
Volume: 32
Issue number: 12
ISSN (Print): 0142-9612
Ratings: 
  • Scopus rating (2011): CiteScore 11.3 SJR 3.302 SNIP 2.203
Original language: English
ASJC Scopus subject areas: Biomaterials, Bioengineering, Ceramics and Composites, Mechanics of Materials, Biophysics
Keywords: Bone regeneration, Co-polylactide/beta-tricalcium phosphate, Composite, Long term study
Source: Scopus
Source ID: 79951769703

Research output: Contribution to journalArticleScientificpeer-review

Direct position control of electro-hydraulic excavator

Position measurement in the electro-hydraulic systems is feasible via the utilization of physical sensors. An improvement in technology has led to the manufacturing of high accurate position sensors for direct position control. This paper proposes utilization of direct position control in an electro-hydraulic system with a new hydraulic zonal system architecture implemented with Direct Driven Hydraulics. It was mentioned in early study that this hydraulic system architecture as a replacement for the traditional valve-based hydraulic systems, has higher energy efficiency rate. In this study, the simulation implementation and experimental verification of Direct Driven Hydraulics (DDH) will be investigated for a micro excavator test case from position control point of view. Results demonstrated that the implementation of DDH in an excavator case will lead to maximum 5 cm error in a single-cycle movement.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Automation and Hydraulic Engineering, Aalto University
Contributors: Danaee, S., Nurmi, J., Minav, T., Mattila, J., Pietola, M.
Publication date: 2018

Host publication information

Title of host publication: BATH/ASME 2018 Symposium on Fluid Power and Motion Control, FPMC 2018
Publisher: ASME
ISBN (Electronic): 9780791851968
ASJC Scopus subject areas: Fluid Flow and Transfer Processes, Control and Systems Engineering
Source: Scopus
Source ID: 85058007169

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

On entropy-based molecular descriptors: Statistical analysis of real and synthetic chemical structures

This paper presents an analysis of entropy-based molecular descriptors. Specifically, we use real chemical structures, as well as synthetic isomeric structures, and investigate properties of and among descriptors with respect to the used data set by a statistical analysis. Our numerical results provide evidence that synthetic chemical structures are notably different to real chemical structures and, hence, should not be used to investigate molecular descriptors. Instead, an analysis based on real chemical structures is favorable. Further, we find strong hints that molecular descriptors can be partitioned into distinct classes capturing complementary information.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: TU Vienna, Technical University Darmstadt, Computational Biology and Machine Learning, School of Medicine
Contributors: Dehmer, M., Varmuza, K., Borgert, S., Emmert-Streib, F.
Number of pages: 9
Pages: 1655-1663
Publication date: 27 Jul 2009
Peer-reviewed: Yes

Publication information

Journal: Journal of Chemical Information and Modeling
Volume: 49
Issue number: 7
ISSN (Print): 1549-9596
Ratings: 
  • Scopus rating (2009): SJR 1.039 SNIP 1.219
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Chemistry(all), Computer Science Applications, Library and Information Sciences
Source: Scopus
Source ID: 68149167631

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

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

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

Development and characterization of poly(ε-caprolactone) hollow fiber membranes for vascular tissue engineering

The fabrication of tissue-engineered scaffolds for small-caliber blood vessels still remains a challenge. In the present work, we prepared poly(ε-caprolactone) (PCL) hollow fiber (HF) membranes, suitable for small-diameter blood vessel regeneration, by a phase separation spinning technique. The difficulty of processing PCL, a highly elastic material prone to suffer die swelling by extrusion, was overcome by tailoring the dope solution temperature and extrusion flow rate during the spinning procedure. The influence of the composition of the coagulation bath (water, ethanol, isopropanol) on the HF membrane physico-chemical properties (morphology, transport and mechanical properties) and cell attachment and proliferation was studied. The HF membranes fabricated using ethanol as coagulation bath had the most uniform morphology, good mechanical and transport properties and showed human adipose stem cell attachment and proliferation. Therefore, these fibers are promising scaffolds for small-caliber blood vessel regeneration.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Integrated Technologies for Tissue Engineering Research (ITTE), University of Cantabria, University of Twente
Contributors: Diban, N., Haimi, S., Bolhuis-Versteeg, L., Teixeira, S., Miettinen, S., Poot, A., Grijpma, D., Stamatialis, D.
Number of pages: 9
Pages: 29-37
Publication date: 1 Jul 2013
Peer-reviewed: Yes

Publication information

Journal: Journal of Membrane Science
Volume: 438
ISSN (Print): 0376-7388
Ratings: 
  • Scopus rating (2013): CiteScore 8.2 SJR 2.451 SNIP 1.98
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Materials Science(all), Biochemistry, Filtration and Separation
Keywords: Adipose stem cell, Hollow fiber, Phase-inversion, Poly(ε-caprolactone), Vascular regeneration
Source: Scopus
Source ID: 84876440642

Research output: Contribution to journalArticleScientificpeer-review

Chemolithotrophic denitrification in biofilm reactors

Chemolithotrophic denitrification is an inexpensive and advantageous process for nitrate removal and represents a promising alternative to classical denitrification with organics. Chemolithotrophic denitrifiers are microorganisms able to reduce nitrate and nitrite using inorganic compounds as source of energy. Ferrous iron, sulfur-reduced compounds (e.g. hydrogen sulfide, elemental sulfur and thiosulfate), hydrogen gas, pyrite and arsenite have been used as inorganic electron donors resulting in diverse outcomes. In the last 40years, a large number of engineered systems have been used to maintain chemolithotrophic denitrification and improve rate and efficiency of the process. Among them, biofilm reactors proved to be robust and high-performing technologies. Packed bed reactors are particularly suitable for the removal of low nitrate concentrations, since high retention times are required to complete denitrification. Fluidized bed and membrane biofilm reactors result in the highest denitrification rates (>20kg N-NO<inf>3</inf><sup>-</sup>/m<sup>3</sup>d) when hydrogen gas and sulfur reduced compounds are used as electron donors. Hydrogen gas pressure and current intensity rule the performance of membrane biofilm and biofilm electrode reactors, respectively. Biofouling is the most common and detrimental issue in biofilm reactors. Bed fluidization and hydrogen supply limitation are convenient and effective solutions to mitigate biofouling.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Urban circular bioeconomy (UrCirBio), Department of Chemistry and Bioengineering, Research group: Industrial Bioengineering and Applied Organic Chemistry, Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio
Contributors: Di Capua, F., Papirio, S., Lens, P. N. L., Esposito, G.
Number of pages: 15
Pages: 643-657
Publication date: 2015
Peer-reviewed: Yes
Early online date: 15 Jun 2015

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: Biofilm, Biofilm electrode reactor, Chemolithotrophic denitrification, Fluidized bed reactor, Membrane biofilm reactor, Packed bed reactor

Bibliographical note

AUX=keb,"Di Capua, Francesco"
EXT="Papirio, Stefano"

Source: Scopus
Source ID: 84932636341

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

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

Deformability analysis and improvement in stretchable electronics systems through finite element analysis

Stretchable electronic systems employ a combination of extremely deformable substrates with electrically conductive inks printed on their surface, on which components are connected. The absence of solid metal as conductive material greatly enhances the deformability of these systems. However, although being able to sustain high deformation, the presence of rigid components heavily affects the achievable deformation levels due to strain concentrations near the interconnection area. In order to improve stretchability under these conditions, a combination of research on materials for conductive inks and optimization of the employed layout is needed. Especially for the latter, the use of Finite Element (FE) modeling is very useful, since it allows to locate critical regions for deformation behavior and to perform design optimization and instability analyses. In this work, the authors show the application of this strategy to improve mechano-electrical performance of the system under uniaxial tension by modelling and then modifying the overall stiffness of specific sample regions. Depending on the specific need, different strategies can be adopted to intervene on stiffness changes, such as material addition to specific regions. This work shows that, in particular, a simple technique such as laser cutting can be used to tailor the local material parameters at a deeper level, thus allowing decrease in stiffness gradients and a general enhancement of electrical performances under high levels of uniaxial deformation of the sample, as also predicted in the FE analyses.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electrical Engineering, Research group: Plastics and Elastomer Technology, Research group: Laboratory for Future Electronics, Materials Science and Environmental Engineering
Contributors: Di Vito, D., Mosallaei, M., Vahed, B. K., Kanerva, M., Mäntysalo, M.
Number of pages: 9
Pages: 755-763
Publication date: 2020

Host publication information

Title of host publication: Proceedings of XXIV AIMETA Conference 2019
Publisher: Springer
Editors: Carcaterra, A., Graziani, G., Paolone, A.
ISBN (Print): 9783030410568
ISBN (Electronic): 978-3-030-41057-5

Publication series

Name: Lecture Notes in Mechanical Engineering
ISSN (Print): 2195-4356
ISSN (Electronic): 2195-4364
ASJC Scopus subject areas: Automotive Engineering, Aerospace Engineering, Mechanical Engineering, Fluid Flow and Transfer Processes
Keywords: FEM, Optimization, Stretchable electronics
Electronic versions: 
URLs: 

Bibliographical note

jufoid=79273

Source: Scopus
Source ID: 85083958324

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

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

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

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

Stearate Modified Zinc-Aluminum Layered Double Hydroxides and Acrylonitrile Butadiene Rubber Nanocomposites

The aim of this investigation is to highlight the potentials of layered double hydroxides (LDH) and to serve as a replacement for zinc oxide and stearic acid from the basic rubber formulation. This will eventually result in about a 10× significant reduction of Zn2+ ion concentration in the final compound. The unique advantage of stearate ion-modified LDH is the delivery of zinc ions to accelerate and stearate ions to activate the vulcanization process. Furthermore, it can also reinforce the rubber matrix by virtue of its layered structure as nanofiller.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Engineering materials science and solutions (EMASS), Vodafone Department of Mobile Communications Systems, Leibniz-Institut für Polymerforschung Dresden E.V., Rubber Technology Centre, Indian Institute of Technology Kharagpur
Contributors: Eshwaran, S. B., Basu, D., Kutlu, B., Leuteritz, A., Wagenknecht, U., Stöckelhuber, K. W., Naskar, K., Das, A., Heinrich, G.
Number of pages: 9
Pages: 65-73
Publication date: Jan 2014
Peer-reviewed: Yes

Publication information

Journal: Polymer-Plastics Technology and Engineering
Volume: 53
Issue number: 1
ISSN (Print): 0360-2559
Ratings: 
  • Scopus rating (2014): CiteScore 3.9 SJR 0.664 SNIP 1.117
Original language: English
ASJC Scopus subject areas: Polymers and Plastics, Materials Science (miscellaneous), Chemical Engineering(all), Materials Chemistry
Keywords: Layered double hydroxide, Nitrile rubber, Sulfur vulcanization, Zinc oxide
Source: Scopus
Source ID: 84891541802

Research output: Contribution to journalArticleScientificpeer-review

EMBEC & NBC 2017: Joint Conference of the European Medical and Biological Engineering Conference (EMBEC) and the Nordic-Baltic Conference on Biomedical Engineering and Medical Physics (NBC), Tampere, Finland, June 2017

This volume presents the proceedings of the joint conference of the European Medical and Biological Engineering Conference (EMBEC) and the Nordic-Baltic Conference on Biomedical Engineering and Medical Physics (NBC), held in Tampere, Finland, in June 2017.

The proceedings present all traditional biomedical engineering areas, but also highlight new emerging fields, such as tissue engineering, bioinformatics, biosensing, neurotechnology, additive manufacturing technologies for medicine and biology, and bioimaging, to name a few. Moreover, it emphasizes the role of education, translational research, and commercialization.

General information

Publication status: Published
MoE publication type: C2 Edited books
Organisations: BioMediTech, Faculty of Biomedical Sciences and Engineering, Research group: Quantitative medical imaging, Research group: Computational Biophysics and Imaging Group
Contributors: Eskola, H. (ed.), Väisänen, O. (ed.), Viik, J. (ed.), Hyttinen, J. (ed.)
Number of pages: 1,139
Publication date: 2017

Publication information

Publisher: Springer
ISBN (Print): 978-981-10-5121-0
ISBN (Electronic): 978-981-10-5122-7
Original language: English

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Source: Scopus
Source ID: 85024836985

Research output: Book/ReportAnthologyScientificpeer-review

Chemically tailored dielectric-to-metal transition for the design of metamaterials from nanoimprinted colloidal nanocrystals

We demonstrate optical metamaterial design using colloidal gold nanocrystal building blocks. In the solid state, chemically exchanging the nanocrystals' surface-capping molecules provides a tailorable dielectric-to-metal transition exhibiting a 1010 range in DC conductivity and dielectric permittivity ranging from everywhere positive to everywhere negative throughout the visible-to-near-IR. Direct, wide-area nanoimprinting of subwavelength superstructures at room temperature, on plastic and glass substrates, affords plasmonic resonances ranging from 660 to 1070 nm, in agreement with numerical simulations.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: University of Pennsylvania, Department of Electrical and Systems Engineering
Contributors: Fafarman, A. T., Hong, S. H., Caglayan, H., Ye, X., Diroll, B. T., Paik, T., Engheta, N., Murray, C. B., Kagan, C. R.
Number of pages: 8
Pages: 350-357
Publication date: 13 Feb 2013
Peer-reviewed: Yes

Publication information

Journal: Nano Letters
Volume: 13
Issue number: 2
ISSN (Print): 1530-6984
Ratings: 
  • Scopus rating (2013): CiteScore 22.6 SJR 9.081 SNIP 3.355
Original language: English
ASJC Scopus subject areas: Bioengineering, Chemistry(all), Materials Science(all), Condensed Matter Physics, Mechanical Engineering
Keywords: ammonium thiocyanate, dielectric function, gold nanoparticles, ligand exchange, Plasmonics, soft lithography

Bibliographical note

EXT="Caglayan, Humeyra"

Source: Scopus
Source ID: 84873680258

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

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

Sol-gel synthesis of quaternary (P2O5)55-(CaO)25-(Na2O)(20-x)-(TiO2) x bioresorbable glasses for bone tissue engineering applications (x = 0, 5, 10, or 15)

In the present study, we report a new and facile sol-gel synthesis of phosphate-based glasses with the general formula of (P2O5)55-(CaO)25-(Na2O)(20-x)-(TiO2) x , where x = 0, 5, 10 or 15, for bone tissue engineering applications. The sol-gel synthesis method allows greater control over glass morphology at relatively low processing temperature (200 °C) in comparison with phosphate-based melt-derived glasses (~1000 °C). The glasses were analyzed using several characterization techniques, including x-ray diffraction (XRD), (31)P magic angle spinning nuclear magnetic resonance ((31)P MAS-NMR), Fourier transform infrared (FTIR) spectroscopy and energy-dispersive x-ray (EDX) spectroscopy, which confirmed the amorphous and glassy nature of the prepared samples. Degradation was assessed by measuring the ion release and pH change of the storage medium. Cytocompatibility was also confirmed by culturing osteoblast-like osteosarcoma cell line MG-63 on the glass microparticles over a seven-day period. Cell attachment to the particles was imaged using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The results revealed the potential of phosphate-based sol-gel derived glasses containing 5 or 10 mol% TiO2, with high surface area, ideal dissolution rate for cell attachment and easily metabolized dissolution products, for bone tissue engineering applications.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Integrated Technologies for Tissue Engineering Research (ITTE), UCL Eastman Dental Institute
Contributors: Foroutan, F., Walters, N. J., Owens, G. J., Mordan, N. J., Kim, H. W., de Leeuw, N. H., Knowles, J. C.
Number of pages: 1
Pages: 45025
Publication date: 1 Aug 2015
Peer-reviewed: Yes

Publication information

Journal: Biomedical materials (Bristol, England)
Volume: 10
Issue number: 4
Ratings: 
  • Scopus rating (2015): CiteScore 5.1 SJR 1.118 SNIP 1.118
Original language: English
ASJC Scopus subject areas: Bioengineering, Biomaterials, Biomedical Engineering

Research output: Contribution to journalArticleScientificpeer-review

Biomimetic surface modification of polycarbonateurethane film via phosphorylcholine-graft for resisting platelet adhesion

Phosphorylcholine groups were covalently introduced onto a polycarbonateurethane (PCU) surface in order to create a biomimetic structure on the polymer surfaces. After introducing primary amine groups onto the polymer surface by 1,6-hexanediamine, phosphorylcholine groups were covalently linked onto the surface by the reductive amination between the amino group and the aldehyde group of phosphorylcholine glyceraldehyde (PCGA). The results of water contact angle test, X-ray photoelectron spectroscopy (XPS), and X-ray fluorescence spectrometer (XRF) analysis of the modified films indicated that PCGA had already been covalently linked to the PCU surface. The topographies and surface roughnesses were both imaged and measured by atomic force microscopy (AFM). Scanning electron microscopy (SEM) observation of the PCU films after treatment with platelet-rich plasma demonstrated that platelets had rarely adhered to the surface of the PCGA-grafted PCU films but had mainly adhered to the surface of the blank PCU films. The platelet adhesion result indicated that the PC modified PCU films could resist platelet adhesion after grafting with PCGA, and that these PCGA-grafted PCU materials, potentially, might be applied as blood-contacting materials.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Integrated Technologies for Tissue Engineering Research (ITTE), Tianjin University, School of Chemical Engineering and Technology
Contributors: Gao, W., Feng, Y., Lu, J., Khan, M., Guo, J.
Number of pages: 7
Pages: 1063-1069
Publication date: Oct 2012
Peer-reviewed: Yes

Publication information

Journal: Macromolecular Research
Volume: 20
Issue number: 10
ISSN (Print): 1598-5032
Ratings: 
  • Scopus rating (2012): CiteScore 2.2 SJR 0.569 SNIP 0.801
Original language: English
ASJC Scopus subject areas: Organic Chemistry, Materials Chemistry, Polymers and Plastics, Chemical Engineering(all)
Keywords: Biomimetic, Phosphorylcholine glyceraldehydes, Platelet adhesion, Polycarbonateurethane, Surface modification
Source: Scopus
Source ID: 84867230066

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

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

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

Reproducible preparation method of hydrogels for cell culture applications – Case study with spermidine crosslinked gellan gum

Hydrogels are promising materials to culture cells in 3D environment. Their mechanical properties are decisive, as cells understand the stiffness of their surroundings. Herein, a method is presented to produce ionically crosslinked hydrogel matrices. A reproducible method is needed, because conventional methods cause inconsistent properties. The investigated material is gellan gum, crosslinked with the bioamine spermidine. Samples were prepared with the more conventional ‘pipetting’ technique and with self-developed ‘uniform mixing’ technique. The two preparation techniques are described in detail and the obtained hydrogels are compared. The mechanical properties are analyzed with compression testing. The obtained results show that samples by the so-called ‘uniform mixing’ method have more uniform dimensions and higher compression modulus. A preliminary stability test in cell culture medium was also carried out.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: BioMediTech, Faculty of Biomedical Sciences and Engineering, Research group: Biomaterials and Tissue Engineering Group
Contributors: Gering, C., Koivisto, J. T., Parraga, J. E., Kellomäki, M.
Number of pages: 4
Pages: 811-814
Publication date: 2018

Host publication information

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

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: 3D cell culture, Compression modulus, Gellan gum, Hydrogel, Spermidine

Bibliographical note

jufoid=58152

Source: Scopus
Source ID: 85021737623

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

Towards universal enrichment nanocoating for IR-ATR waveguides

Polymer multilayered nanocoating capable of concentrating various chemical substances at IR-ATR waveguide surfaces is described. The coating affinity to an analyte played a pivotal role in sensitivity enhancement of the IR-ATR measurements, since the unmodified waveguide did not show any analyte detection.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Frontier Photonics, Clemson University, School of Materials Science and Engineering/COMSET, University of Delaware, Massachusetts Institute of Technology
Contributors: Giammarco, J., Zdyrko, B., Petit, L., Musgraves, J. D., Hu, J., Agarwal, A., Kimerling, L., Richardson, K., Luzinov, I.
Number of pages: 3
Pages: 9104-9106
Publication date: 28 Aug 2011
Peer-reviewed: Yes

Publication information

Journal: Chemical Communications
Volume: 47
Issue number: 32
ISSN (Print): 1359-7345
Ratings: 
  • Scopus rating (2011): CiteScore 7.9 SJR 2.889 SNIP 1.326
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: 79961012632

Research output: Contribution to journalArticleScientificpeer-review

Enrichment polymer layers for detection of volatile vapors by ATR FT-IR

Fourier Transformed Infrared Spectroscopy (FT-IR) is an effective analytical method for the identification of organic compounds be they man made or naturally produced. There is, however, a limitation to what a normal FT-IR can detect if an analyte is in vapor phase or in low concentration. To this end, we have applied enrichment polymer layer systems (EPLS) to an attenuated total reflection (ATR) crystal waveguide to enhance detection capability for the method. These EPLS are comprised of polymers with different functionality along the backbone and provide unique interaction capabilities that can attract volatile chemicals and concentrate them in the evanescence wave region. The thickness of the polymer layers is kept on 30-50nm level. The EPLS were characterized by atomic force microscopy, ellipsometry and FT-IR. The overall goal of this work is to construct a "universal" sensor platform capable of detecting a wide range of volatile organic chemicals via infrared spectroscopy.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Frontier Photonics, Massachusetts Institute of Technology, School of Materials Science and Engineering/COMSET, Clemson University, Department of Materials Science and Engineering, University of Delaware
Contributors: Giammarco, J. M., Zdyrko, B., Hu, J., Agarwal, A., Kimerling, L., Carlie, N., Petit, L., Richardson, K., Luzinov, I.
Publication date: 2011
Peer-reviewed: Yes

Publication information

Journal: ACS National Meeting Book of Abstracts
ISSN (Print): 0065-7727
Ratings: 
  • Scopus rating (2011): SJR 0.101 SNIP 0
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all)
Source: Scopus
Source ID: 80051876637

Research output: Contribution to journalArticleScientificpeer-review

Shape-dependent plasmonic response and directed self-assembly in a new semiconductor building block, indium-doped cadmium oxide (ICO)

The influence of particle shape on plasmonic response and local electric field strength is well-documented in metallic nanoparticles. Morphologies such as rods, plates, and octahedra are readily synthesized and exhibit drastically different extinction spectra than spherical particles. Despite this fact, the influence of composition and shape on the optical properties of plasmonic semiconductor nanocrystals, in which free electrons result from heavy doping, has not been well-studied. Here, we report the first observation of plasmonic resonance in indium-doped cadmium oxide (ICO) nanocrystals, which exhibit the highest quality factors reported for semiconductor nanocrystals. Furthermore, we are able to independently control the shape and free electron concentration in ICO nanocrystals, allowing for the influence of shape on the optical response of a plasmonic semiconductor to be conclusively demonstrated. The highly uniform particles may be self-assembled into ordered single component and binary nanocrystal superlattices, and in thin films, exhibit negative permittivity in the near infrared (NIR) region, validating their use as a new class of tunable low-loss plasmonic building blocks for 3-D optical metamaterials.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: University of Pennsylvania, Purdue University, Department of Electrical and Systems Engineering
Contributors: Gordon, T. R., Paik, T., Klein, D. R., Naik, G. V., Caglayan, H., Boltasseva, A., Murray, C. B.
Number of pages: 7
Pages: 2857-2863
Publication date: 12 Jun 2013
Peer-reviewed: Yes

Publication information

Journal: Nano Letters
Volume: 13
Issue number: 6
ISSN (Print): 1530-6984
Ratings: 
  • Scopus rating (2013): CiteScore 22.6 SJR 9.081 SNIP 3.355
Original language: English
ASJC Scopus subject areas: Bioengineering, Chemistry(all), Materials Science(all), Condensed Matter Physics, Mechanical Engineering
Keywords: indium-doped cadmium oxide, metamaterials, nanocrystal superlattices, Plasmonics, shape effects, transparent conducting oxide

Bibliographical note

EXT="Caglayan, Humeyra"

Source: Scopus
Source ID: 84879097164

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

Nonlinear local projection filter for impedance pneumography

The ability of impedance pneumography (IP) for recording tidal flow during long periods of free breathing make it a promising tool for assessing temporal complexity of respiration. However, techniques quantifying complexity may be sensitive to the noise in the IP signal resulting from the current processing method. A nonlinear local projection filter (NLPF) is presented as the solution to the current linear processing method, failing to reduce noise without distorting the flow signal. Current and proposed NLPF methods were applied to and existing data set of raw IP recorded in 21 infants during a methacholine challenge test. Methods’ performance was compared in a battery of test using mouth flow as a reference. NLPF achieved lower sample-by-sample error, and higher frequency attenuation, while linearity with mouth flow was maintained. Therefore, we concluded that NLPF superiorly reduces noise without distorting respiratory information.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Faculty of Biomedical Sciences and Engineering, Research group: Physiological Measurement Systems and Methods Group, BioMediTech, Helsinki University Central Hospital
Contributors: Gracia, J., Seppä, V. P., Pelkonen, A., Kotaniemi-Syrjänen, A., Mäkelä, M., Malmberg, P., Viik, J.
Number of pages: 4
Pages: 306-309
Publication date: 2018

Host publication information

Title of host publication: EMBEC and NBC 2017 - Joint Conference of the European Medical and Biological Engineering Conference EMBEC 2017 and the Nordic-Baltic Conference on Biomedical Engineering and Medical Physics, NBC 2017
Place of publication: Singapore
Publisher: Springer Verlag
ISBN (Print): 9789811051210
ISBN (Electronic): 978-981-10-5122-7

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: Impedance pneumography, Lung function, Noise reduction, Nonlinear filter

Bibliographical note

jufoid=58152

Source: Scopus
Source ID: 85021722594

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

Ectopic Beat Detection from Wrist Optical Signals for Sinus Rhythm and Atrial Fibrillation Subjects

Ectopic beats are abnormal cardiac beats originating from a location different than the sino-atrial node and therefore not being controlled by the autonomous nervous system. Thus, correct heart rate variability analysis inevitably requires accurate ectopic beat detection. Furthermore, an accurate ectopic beat detection is crucial to differentiate irregular cardiac rhythm due to different types of pathological arrhythmias from those caused by isolated ectopic beats. In this paper, we present an algorithm for ectopic beat detection based on wrist plethysmographic (PPG) signals. The proposed algorithm relies on analyzing the inter-beat patterns while considering the heart-rhythm condition; whether sinus rhythm (SR) or atrial fibrillation (AF). We monitor 29 patients recovering from surgery in the post-anesthesia care unit. During the recordings, 15 patients had SR and 14 patients had AF. The proposed ectopic beat detection algorithm achieves a sensitivity of and a specificity of 2.12.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: BioMediTech, Research group: Sensor Technology and Biomeasurements (STB), PulseOn SA, Tampere University Hospital, Pulseon Oy, Tampere University
Contributors: Haddad, S., Harju, J., Tarniceriu, A., Halkola, T., Parak, J., Korhonen, I., Yli-Hankala, A., Vehkaoja, A.
Number of pages: 9
Pages: 150-158
Publication date: 2020

Host publication information

Title of host publication: 15th Mediterranean Conference on Medical and Biological Engineering and Computing – MEDICON 2019 - Proceedings of MEDICON 2019
Publisher: Springer
Editors: Henriques, J., de Carvalho, P., Neves, N.
ISBN (Print): 9783030316341

Publication series

Name: IFMBE Proceedings
Volume: 76
ISSN (Print): 1680-0737
ISSN (Electronic): 1433-9277
ASJC Scopus subject areas: Bioengineering, Biomedical Engineering
Keywords: Atrial fibrillation, Ectopic beat detection, Heart rate variability, Photoplethysmography

Bibliographical note

EXT="Parak, Jakub"
dupl=51710603

Source: Scopus
Source ID: 85075876200

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

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

Lithography-free oxide patterns as templates for self-catalyzed growth of highly uniform GaAs nanowires on Si(111)

We report self-catalyzed growth of GaAs nanowires (NWs) on Si/SiO<inf>x</inf> patterns fabricated by a lithography-free method. The patterns are defined using droplet epitaxy of GaAs nanocrystals, spontaneous oxidation, and thermal annealing. We investigate the influence of the size and density of the nucleation sites on the NW growth process and show that this approach enables the fabrication of highly uniform GaAs NWs with controllable density. The pattern fabrication and NW growth process are studied and discussed in relation to the surface morphology and chemical properties of the Si/SiO<inf>x</inf> patterns. Furthermore, the optical quality of the NWs is investigated by photoluminescence experiments performed for GaAs-AlGaAs core-shell NWs.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Optoelectronics Research Centre, Research group: Semiconductor Technology and Applications, Augmented Human Activities (AHA), Frontier Photonics, Department of Physics and Astronomy, University of Turku, University of Turku
Contributors: Hakkarainen, T. V., Schramm, A., Mäkelä, J., Laukkanen, P., Guina, M.
Publication date: 18 Jul 2015
Peer-reviewed: Yes

Publication information

Journal: Nanotechnology
Volume: 26
Issue number: 27
Article number: 275301
ISSN (Print): 0957-4484
Ratings: 
  • Scopus rating (2015): CiteScore 6.6 SJR 1.257 SNIP 1.117
Original language: English
ASJC Scopus subject areas: Bioengineering, Chemistry(all), Electrical and Electronic Engineering, Mechanical Engineering, Mechanics of Materials, Materials Science(all)
Keywords: droplet epitaxy, GaAs, nanowires, self-catalyzed

Bibliographical note

EXT="Laukkanen, P."

Source: Scopus
Source ID: 84934916555

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

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

Miniaturized stimulator for imaging of live cell responses to high frequency mechanical vibration

Cellular mechanobiology is highly important for tissue development and disease formation. However, lack of proper tools limit investigation of the cellular responses to different mechanical cues. High frequency (HF) vibration has already been applied in different cellular applications, but the knowledge of the stimulation effect on cells is limited. To meet this challenge, we designed a HF vibration stimulator for combined mechanical manipulation of live cells and high-resolution light-microscopy. Our system utilizes a commercial miniaturized speaker to vibrate a 3D printed sample vehicle horizontally. Technical tests demonstrated excellent performance at lower frequencies (30–60 Hz), enabling even high magnitude (HMHF, Gpeak ≥ 1 Gpeak ) method. Real-time acceleration measurement and light-microscopy both revealed accurately and precisely produced low magnitude (LMHF, Gpeak < 1 Gpeak ) vibrations. With our system, we could observe cellular responses to the LMHF (0.2 Gpeak , 30 Hz) vibration. In this paper, we introduce an inexpensive stimulation platform for the mechanobiology research of different cell applications.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Research group: Computational Biophysics and Imaging Group, BioMediTech
Contributors: Halonen, H. T., Hyttinen, J. A., Ihalainen, T. O.
Number of pages: 7
Pages: 21-27
Publication date: 11 May 2019

Host publication information

Title of host publication: CMBEBIH 2019 - Proceedings of the International Conference on Medical and Biological Engineering
Publisher: Springer Verlag
Editors: Badnjevic, A., Gurbeta Pokvić, L., Škrbić, R., Badnjevic, A., Gurbeta Pokvić, L.
ISBN (Print): 9783030179700

Publication series

Name: IFMBE Proceedings
Volume: 73
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Bioengineering, Biomedical Engineering
Keywords: High frequency vibration, Live cell imaging, Mechanotransduction

Bibliographical note

jufoid=58152
dupl=51710515

Source: Scopus
Source ID: 85066029834

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

X-ray microtomography of collagen and polylactide samples in liquids

Methods to image and assess the microstructure of polymer based biomaterials in liquid phase, for example cell culture medium, are well warranted. X-ray microtomography could provide a mean to visualize and analyze such structures. However, the density of such polymers is close to that of water and hence the inherent X-ray contrast is poor. The material can provide good contrast when dry, however, if the materials contain cells and are dried, the cell morphology may be distorted. Moreover the entire structure of these water containing materials are deformed in the drying process. In this paper we tested phosphotungstic acid (PTA) staining to improve the contrast. We imaged collagen and PLA samples, as well as collagen-PLA composites with μCT in air, water and alcohol. The methods were compared visually and with contrast to noise ratio calculated from the images. Our results demonstrate that with alcohol the PLA can be imaged also in liquid phase. PTA staining seems to be a good method to increase the contrast for collagen in μCT imaging.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Department of Electronics and Communications Engineering, Research group: Biomaterials and Tissue Engineering Group, Research group: Computational Biophysics and Imaging Group
Contributors: Hannula, M., Haaparanta, A. M., Tamminen, I., Aula, A., Kellomäki, M., Hyttinen, J.
Number of pages: 5
Pages: 420-424
Publication date: 2016

Host publication information

Title of host publication: XIV Mediterranean Conference on Medical and Biological Engineering and Computing 2016 : MEDICON 2016, March 31st–April 2nd 2016, Paphos, Cyprus
Publisher: Springer Verlag
ISBN (Print): 9783319327013

Publication series

Name: IFMBE Proceedings
Volume: 57
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: Collagen, Polylactide, Staining, μCT imaging

Bibliographical note

JUFOID=58152

Source: Scopus
Source ID: 84968645247

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

µCT based characterization of biomaterial scaffold microstructure under compression

Scaffolds are often designed with progressive degradation to make way for cell proliferation of seeded cells for native tissue. The viability of the scaffold has been shown to depend on, among other things, the microstructure. Common parameters, that are used to describe microstructure, are porosity, material thickness, pore size and surface area. These properties quantify the suitability of the scaffold as a substrate for cell adhesion, fluid exchange and nutrient transfer. Bone and cartilage scaffolds are often placed or operated under loads (predominantly compression). This can alter the structural parameters depending on the stiffness of the scaffold and applied deformation. It is important to know, how scaffolds’ parameters change under deformation. In this study, two scaffolds (PLCL-TCP and collagen-PLA) intended for use in bone and cartilage applications, were studied through micro computed tomography based imaging and in situ mechanical testing. The scaffolds were subjected to uniaxial compressive deformation up to 50% of the original size. The corresponding changes in the individual scaffold bulk characteristics were analyzed. Our results show an expected decrease in porosity with increasing deformation (with PLCL-TCP scaffold 52% deformation resulted in 56% decrease in porosity). Especially in the sandwich constructs of collagen-PLA, but also in PLCL-TCP composites, it was evident that different materials are affected differently which may be of significance in applications with mechanical loading. Our results are a step towards understanding the changes in the structure of these scaffolds under loading.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Faculty of Biomedical Sciences and Engineering, Research group: Computational Biophysics and Imaging Group, Division of Biomedical Engineering, University of Cape Town, Faculty of Health Sciences
Contributors: Hannula, M., Narra, N., Paakinaho, K., Haaparanta, A., Kellomäki, M., Hyttinen, J.
Number of pages: 5
Pages: 165-169
Publication date: 2019

Host publication information

Title of host publication: World Congress on Medical Physics and Biomedical Engineering 2018
Publisher: Springer
ISBN (Electronic): 978-981-10-9023-3

Publication series

Name: IFMBE Proceedings
Volume: 68
No.: 3
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Bioengineering, Biomedical Engineering
Keywords: Biomaterials, Compression, In situ imaging, Porosity, X-ray microtomography
Source: Scopus
Source ID: 85048307904

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

Enhancing CT 3D Images by Independent Component Analysis of Projection Images

Computed tomography (CT) is an imaging modality producing 3D images from sets of 2D X-ray images taken around the object. The images are noisy by nature, and segmentation of the 3D images is tedious. Also, detection of low contrast objects may be difficult, if not impossible. Here, we propose an independent component analysis (ICA) based method to process sets of 2D projection images prior to 3D reconstruction to remove noise, and to enhance objects for detection and segmentation. In this paper, a proof-of-concept is provided: the proposed method was able to separate noise and image components, as well as to make visible objects that were not observable in 3D images without processing. We demonstrate our method in object separation with 2D slice image processing simulations, and by enhancing a 3D image of a polymer sample taken with Xradia MicroXCT-400. The method is applicable in any CT tomography for which a number of project image sets with different contrasts can be taken, e.g., in multispectral fashion.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Research group: Computational Biophysics and Imaging Group, BioMediTech
Contributors: Hannula, M., Hyttinen, J. A., Tanskanen, J. M.
Number of pages: 9
Pages: 381-389
Publication date: 2020

Host publication information

Title of host publication: 15th Mediterranean Conference on Medical and Biological Engineering and Computing – MEDICON 2019 - Proceedings of MEDICON 2019
Publisher: Springer
Editors: Henriques, J., de Carvalho, P., Neves, N.
ISBN (Print): 9783030316341

Publication series

Name: IFMBE Proceedings
Volume: 76
ISSN (Print): 1680-0737
ISSN (Electronic): 1433-9277
ASJC Scopus subject areas: Bioengineering, Biomedical Engineering
Keywords: 3D imaging, Computed tomography, CT, Image processing, Independent component analysis, Micro-CT, µCT

Bibliographical note

dupl=51710539

Source: Scopus
Source ID: 85075871982

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

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

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

General information

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

Host publication information

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

Publication series

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

Bibliographical note

jufoid=58152

Source: Scopus
Source ID: 85021754208

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

Altered synaptic signaling due to β-amyloid interference in astrocytes: A modeling study

Astrocytes are active participants in brain physiology and a known target of pathological processes of several diseases. Using a mathematical model of a tripartite synapse, we investigated the effects of astrocyte intracellular β-amyloid 1-42 fragments on astrocyte Ca2+ signaling and synaptic signal transmission. Our results show that with this model, β-amyloid interference of astrocyte Ca2+ signaling can considerably alter signal transmission at the synapse, and even silence postsynaptic firing. We conclude that when disturbing astrocyte Ca2+ signaling, β-amyloid fragments can potentially contribute to changes in synaptic signaling.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: BioMediTech, Faculty of Biomedical Sciences and Engineering, Research group: Computational Neuro Science-CNS
Contributors: Havela, R., Manninen, T., Linne, M. L.
Number of pages: 4
Pages: 679-682
Publication date: 2018

Host publication information

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

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: Astrocytes, Biophysical modeling, Tripartite synapses, β-amyloid

Bibliographical note

jufoid=58152

Source: Scopus
Source ID: 85021708806

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

Versatile bio-ink for covalent immobilization of chimeric avidin on sol-gel substrates

A bio-ink for covalent deposition of thermostable, high affinity biotin-binding chimeric avidin onto sol-gel substrates was developed. The bio-ink was prepared from heterobifunctional crosslinker 6-maleimidohexanoic acid N-hydroxysuccinimide which was first reacted either with 3-aminopropyltriethoxysilane or 3-aminopropyldimethylethoxysilane to form silane linkers 6-maleimide- N-(3-(triethoxysilyl)propyl)hexanamide or -(ethoxydimethylsilyl)propyl)-hexanamide. C-terminal cysteine genetically engineered to chimeric avidin was reacted with the maleimide group of silane linker in methanol/PBS solution to form a suspension, which was printed on sol-gel modified PMMA film. Different concentrations of chimeric avidin and ratios between silane linkers were tested to find the best properties for the bio-ink to enable gravure or inkjet printing. Bio-ink prepared from 3-aminopropyltriethoxysilane was found to provide the highest amount of active immobilized chimeric avidin. The developed bio-ink was shown to be valuable for automated fabrication of avidin-functionalized polymer films.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Multi-scaled biodata analysis and modelling (MultiBAM), Univ of Oulu, VTT Technical Research Centre of Finland, Tampere University Hospital
Contributors: Heikkinen, J. J., Kivimäki, L., Määttä, J. A. E., Mäkelä, I., Hakalahti, L., Takkinen, K., Kulomaa, M. S., Hytönen, V. P., Hormi, O. E. O.
Number of pages: 6
Pages: 409-414
Publication date: 15 Oct 2011
Peer-reviewed: Yes

Publication information

Journal: Colloids and Surfaces B: Biointerfaces
Volume: 87
Issue number: 2
ISSN (Print): 0927-7765
Ratings: 
  • Scopus rating (2011): CiteScore 4.7 SJR 1.051 SNIP 1.27
Original language: English
ASJC Scopus subject areas: Biotechnology, Colloid and Surface Chemistry, Physical and Theoretical Chemistry, Surfaces and Interfaces
Keywords: Avidin-biotin technology, Biomolecule immobilization, Biosensing, Chimeric avidin, Maleimide, Printing, Sol-gel
Source: Scopus
Source ID: 79960384544

Research output: Contribution to journalArticleScientificpeer-review

Comparison of linear and non-linear heart rate variability indices between preterm infants at their theoretical term age and full term newborns

Heart rate variability (HRV) enables non-invasive evaluation of cardiac autonomic activity. Preterm infants are known to have altered HRV characteristics that remain even when reaching their term age. Little is known about non-linear HRV measures between full term and preterm babies close to their theoretical full term. In this study, we calculated sample entropy, shape-describing parameters (skewness and kurtosis) and detrended fluctuation analysis coefficients α1 and α2 from RR time series of 16 very preterm babies (37 weeks, “FT group”) infants. Compared to the FT group, smaller values of sample entropy and lower values of α1 were found in the PT group. No difference in α2, kurtosis, or skewness was found. This indicates decrease in overall complexity of HR dynamics in the PT group. When various HRV indices, that included also non-linear indices, were projected to the principal component analysis space obtained from the FT group, a good separation between the PT and FT groups was found. The study was limited by a small sample but the results were in line with literature. The combinations of several HRV parameters can be of interest for future studies on the degree of ANS maturity.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Faculty of Biomedical Sciences and Engineering, Research group: Personal Health Informatics-PHI, Research group: Sleep and Sensory Signal Analysis Group-SSSAG, BioMediTech, U1099, Service de Neonatologie Saint Etienne, Service de Neonatologie
Contributors: Helander, E., Khodor, N., Kallonen, A., Värri, A., Patural, H., Carrault, G., Pladys, P.
Number of pages: 4
Pages: 153-156
Publication date: 2018

Host publication information

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

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: Autonomic nervous system, Detrended fluctuation analysis, Heart rate variability, Premature infant, Sample entropy

Bibliographical note

jufoid=58152

Source: Scopus
Source ID: 85021734112

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

Coronary artery disease diagnosis by means of heart rate variability analysis using respiratory information

Heart rate variability (HRV) analysis during exercise has been used to evaluate cardiovascular response to the stress of exercise, which may offer additional value than in rest condition. To properly analyze HRV during exercise, several challenges need to be addressed, such as including respiratory information and removing the dependance with the mean heart rate (HR) level. The objective of this work is to extract parameters from HRV analysis and respiratory information during exercise to evaluate their capability of diagnose coronary artery disease (CAD). Significant differences in mean HR were found due to medication effect in patients with CAD. By correcting the HRV parameters by mean HR, this effect is minimized. Power related to high frequency, when guided by respiration, results to have the best diagnosis capability (AUC > 0.7).

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Faculty of Biomedical Sciences and Engineering, Research group: Physiological Measurement Systems and Methods Group, BioMediTech, CIBER, Imec, Department of Internal Medicine, University of Helsinki, Tampere University Hospital
Contributors: Hernando, D., Kähönen, M., Lázaro, J., Lehtinen, R., Nieminen, T., Nikus, K., Lehtimäki, T., Bailón, R., Viik, J.
Number of pages: 4
Pages: 270-273
Publication date: 2018

Host publication information

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

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: CAD diagnosis, Exercise test, Respiratory rate

Bibliographical note

jufoid=58152

Source: Scopus
Source ID: 85021756438

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

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

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

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

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

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

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

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

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

Biokalvojen rakenteen ja toiminnan simulointi tuo uutta tietoa rasvoista

The article discusses the importance of lipid membranes in biological systems and the use of molecular dynamics simulations to explore their structure and function. Results from a recent study on the effects of polyunsaturation on a phospholipid membrane are presented [Biophys. J. 73 (1997) 2907].

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: University of Oulu
Contributors: Hyvönen, M. T., Rantala, T. T., Ala-Korpela, M.
Number of pages: 4
Pages: 222-225
Publication date: 1999
Peer-reviewed: Yes

Publication information

Journal: Kemia - Kemi
Volume: 26
Issue number: 3
ISSN (Print): 0355-1628
Ratings: 
  • Scopus rating (1999): SJR 0.129 SNIP 0.113
Original language: Finnish
ASJC Scopus subject areas: Chemical Engineering(all)
Source: Scopus
Source ID: 0043139016

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

Automated pipeline for brain ROI analysis with results comparable to previous freehand measures in clinical settings

Diffusion tensor imaging (DTI) has become a relatively common MR imaging technique in only 10 years. DTI can provide important information of brain microstructure in vivo. Many quantitative DTI analysis methods utilize either region of interest (ROI) or voxel-wise whole-brain methods. ROI methods do not require potentially bias-inducing image data altering, e.g., resampling and smoothing, and are the preferred method in clinical settings. We present an automated pipeline for quantitative ROI analysis of brain DTI data. The pipeline includes pre-processing, registrations, and calculation of mean (and SD) DTI scalar values from the automated ROIs. In addition to atlas regions, the pipeline accepts freehand ROIs, as long as the frame of reference is also provided. By the uniquely designed pipeline, we ensure that the results can be retrospectively compared to previously conducted manual freehand ROI measurement results, if desired. We validated the feasibility of the pipeline by comparing manual freehand ROI measurement results from 40 subjects against the results obtained from automated ROIs. A single set of freehand ROIs (drawn similarly to the original freehand manual ROIs in the population) was input to the pipeline, and the resulting scalar values from the automated ROIs were compared to the manual freehand ROIs’ data. Adopting a limit for goodness of fit of z = ± 1.6 resulted in 94 % success rate for the pipeline’s automated ROI registrations in the whole population. The pipeline can reduce the time taken in clinical ROI measurements.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Faculty of Biomedical Sciences and Engineering, Research group: Quantitative medical imaging, BioMediTech, BioMediTech Institute, Department of Radiology, Pirkanmaan sairaanhoitopiiri
Contributors: Ilvesmäki, T., Hakulinen, U., Eskola, H.
Number of pages: 4
Pages: 635-638
Publication date: 2018

Host publication information

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

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: Atlas, DTI, Image analysis, Pipeline, ROI

Bibliographical note

jufoid=58152

Source: Scopus
Source ID: 85021741082

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

Learned vs. hand-designed features for ECG beat classification: A comprehensive study

In this study, in order to find out the best ECG classification performance we realized comparative evaluations among the state-of-the-art classifiers such as Convolutional Neural Networks (CNNs), multi-layer perceptrons (MLPs) and Support Vector Machines (SVMs). Furthermore, we compared the performance of the learned features from the last convolutional layer of trained 1-D CNN classifier against the handcrafted features that are extracted by Principal Component Analysis, Hermite Transform and Dyadic Wavelet Transform. Experimental results over the MIT-BIH arrhythmia benchmark database demonstrate that the single channel (raw ECG data based) shallow 1D CNN classifier over the learned features in general achieves the highest classification accuracy and computational efficiency. Finally, it is observed that the use of the learned features on either SVM or MLP classifiers does not yield any performance improvement.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Signal Processing, Research group: Video, Research group: Multimedia Research Group - MRG, Qatar University, Izmir University of Economics
Contributors: Ince, T., Zabihi, M., Kiranyaz, S., Gabbouj, M.
Number of pages: 4
Pages: 551-554
Publication date: 2018

Host publication information

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

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: Convolutional neural networks, Learned and hand-crafted features, Real-time ECG classification

Bibliographical note

jufoid=58152
EXT="Kiranyaz, S."
EXT="Ince, T."

Source: Scopus
Source ID: 85021707201

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

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

Effect of micro-aeration and leachate replacement on COD solubilization and VFA production during mono-digestion of grass-silage in one-stage leach-bed reactors

The effect of micro-aeration and leachate replacement with fresh water on chemical oxygen demand (COD) solubilization and volatile fatty acid (VFA) production during the mono-digestion of grass-silage in one-stage leach-bed reactors (LBRs) was investigated in four LBRs, L0 (control), L1, L2 and L3 in batch mode at 35 ± 1 °C for 57 days. Results showed that leachate replacement without pH adjustment (L3) resulted in 2.7 and 1.3 times more SCOD in the leachate compared to control (L0) or leachate replacement with initial pH adjustment (L1), respectively. Micro-aeration at flow rate of 1 L min-1 (2.5 L of air) in L2 resulted in 4-fold increase in VFA production (from 2.2 to 9 g L-1) without any significant increase in cumulative SCOD in the leachate. Increasing the air flow rate to 4 L min-1 (24 L of air) in L2 resulted in a decrease in SCOD extraction. Leachate replacement without pH adjustment (L3) resulted in higher (mean) specific SCOD production (0.51 g SCOD g-1 VSadded) than control (L0, 0.34 g SCOD g-1 VSadded), leachate replacement with initial pH adjustment (L1, 0.33 g SCOD g-1 VSadded) or micro-aeration (L2, 0.32 g SCOD g-1 VSadded). These results suggest that the challenge of hydrolysis during anaerobic digestion of particulate substrates like grass-silage can be improved by micro-aeration and leachate replacement methods with or without pH adjustment.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Jyväskylän yliopisto, University of Jyväskylä
Contributors: Jagadabhi, P. S., Kaparaju, P., Rintala, J.
Number of pages: 7
Pages: 2818-2824
Publication date: Apr 2010
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 101
Issue number: 8
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2010): SJR 2.089 SNIP 2.348
Original language: English
ASJC Scopus subject areas: Bioengineering, Environmental Engineering, Waste Management and Disposal
Keywords: Grass-silage, Leach-bed reactor, Leachate replacement, Micro-aeration, Solubilization
Source: Scopus
Source ID: 73749087133

Research output: Contribution to journalArticleScientificpeer-review

Two-stage anaerobic digestion of tomato, cucumber, common reed and grass silage in leach-bed reactors and upflow anaerobic sludge blanket reactors

Anaerobic digestion of tomato, cucumber, common reed and grass silage was studied in four separate two-stage reactor configuration consisting of leach bed reactor (LBR) and upflow anaerobic sludge blanket reactor (UASB). LBR studies showed that COD solubilization for cucumber and grass silage was higher (50%) than tomato (35%) and common reed (15%). Results also showed that 31-39% of initial TKN present in tomato and cucumber was solubilized in the leachates and 47-54% of the solubilized TKN was converted to NH4-N. The corresponding values for common reed and grass silage were 38-50% and 18-36%, respectively. Biomethanation of the leachates in UASB reactors resulted in methane yields of 0.03-0.14m3 CH4 kg-1VSfed for the studied crop materials. Thus, high COD solubilization, high nitrogen mineralization and solubilization rates were feasible during anaerobic digestion of lignocellulosic materials in a two-stage LBR-UASB reactor system.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Urban circular bioeconomy (UrCirBio), Jyväskylän yliopisto, University of Jyväskylä
Contributors: Jagadabhi, P. S., Kaparaju, P., Rintala, J.
Number of pages: 8
Pages: 4726-4733
Publication date: Apr 2011
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 102
Issue number: 7
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2011): CiteScore 7.9 SJR 2.308 SNIP 2.526
Original language: English
ASJC Scopus subject areas: Bioengineering, Environmental Engineering, Waste Management and Disposal
Keywords: Biogas, Crop materials, Leach bed reactor, Leachate, Two-stage
Source: Scopus
Source ID: 79951945757

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

Understanding selenium biogeochemistry in engineered ecosystems: Transformation and analytical methods

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

General information

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

Host publication information

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

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

Electric field of eeg during anesthesia

Electroencephalogram (EEG) has been clinically used to estimate the level of consciousness during anesthesia, but its physiology and biophysics are poorly understood in anesthe-siological literature. The electrical sources of EEG are in cortical structures. EEG currents create closed-loops, which flow from the surface of the cortex and then return to the inside of the hemispheres. In the case of widespread synchronous activity like physiological sleep or anesthesia, the currents return through the base of brain and skull. Here we show with a typical EEG pattern of anesthesia, burst-suppression, that due to those currents EEG is recordable outside of scalp area. We also present the sensitivity field of electrodes located submentally, as well as the electrodes used for anesthesia monitoring, calculated from a realistic head model of the potential distribution and currents of EEG. Our results show that anesthesia EEG can be recorded with a pair of electrodes anywhere on the surface of head, as well as inside of head and brain, because the EEG current loops produce recordable voltage gradients in the whole head. A pair of electrodes submentally is most sensitive to basal parts of the brain. The typical electrodes used in anesthesia monitoring are most sensitive to basal surface of frontal lobes as well as frontal and mesial parts of temporal lobes.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: BioMediTech, Faculty of Biomedical Sciences and Engineering, Seinäjoki Central Hospital, Central Hospital of Seinäjoki, Aalto University, Aalto University, Tampere University Hospital
Contributors: Jäntti, V., Subramaniyam, N. P., Kamata, K., Ylinen, T., Yli-Hankala, A., Kauppinen, P., Väisänen, O.
Number of pages: 4
Pages: 354-357
Publication date: 2018

Host publication information

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

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: Anesthesia, EEG, Electrode, Montage, Sensitivity

Bibliographical note

jufoid=58152
EXT="Subramaniyam, Narayan Puthanmadam"

Source: Scopus
Source ID: 85021765902

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

Linearity of simultaneously recorded impedance pneumography and direct pneumotachography in thoracic surgery patients

Current assessment of postoperative lung function of thoracic surgery patients based on spirometry requires patient’s mechanical effort. Non-invasive impedance pneumography (IP) has the potential to evaluate postoperative patients while alleviating their effort. The objective of this study was to assess the agreement of IP and pneumotachography (PNT) of adult cardiac and pulmonary surgery patients before and after surgery. IP was measured simultaneously with the flow signal from the mouth for one minute. Pearson correlation coefficient and linearity test were used to evaluate the agreement. 324 measurements had r≥ 0.7 and 23 measurements had r<0.7. Linearity studies revealed that the average deviation from the linearity and sample-by-sample difference were similar between the surgery groups. The visualization shows that there is more deviation from the linearity in the lung resection group than in the cardiac surgery group during inspiration. The linearity was similar perioperatively, thus the surgery did not affect the agreement of IP and PNT. The results indicate that IP is potential to be used for evaluation of postoperative lung functions of cardiac and pulmonary patients.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Faculty of Biomedical Sciences and Engineering, Research group: Physiological Measurement Systems and Methods Group, BioMediTech, Tampere University Hospital, Faculty of Medicine and Life Sciences (Otorhinolaryngology),
Contributors: Jauhiainen, M., Gracia, J., Seppä, V. P., Mahrberg, H., Tuomisto, L., Laurikka, J., Viik, J.
Number of pages: 4
Pages: 1077-1080
Publication date: 2018

Host publication information

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

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: Impedance pneumography, Linearity, Pneumotachography, Thoracic surgery

Bibliographical note

jufoid=58152

Source: Scopus
Source ID: 85021696654

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

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

Optimal short distance electrode locations for impedance pneumography measurement from the frontal thoracic area

Electrical impedance pneumography signal is a valuable tool in qualifying better the person’s health condition. It can be used in monitoring of respiration rate, rhythm and tidal volume. Impedance pneumography has also the potential in ambulatory physiological monitoring systems that are increasingly often implemented using plaster-like on-body devices. In such cases, the area of electrode substrate may be limited and therefore, the electrode configuration, which is able to provide both a clinically valuable electrocardiogram signal and accurate pulmonary information, is an issue. EAS is a useful small area electrode configuration that can be used for electrocardiogram measurements. In this work, different two-electrode bipolar pairs of EAS system are tested for impedance pneumography measurements. Two additional electrodes are also considered in these tests. Our results show that the electrode pair S-A provides the most accurate respiration cycle length and is least affected by movement artifact. Additionally, the results show that this electrode pair produces the signals with highest amplitude.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Department of Electronics and Communications Engineering, Research group: Laboratory for Future Electronics, Department of Automation Science and Engineering, Research area: Microsystems, Research area: Measurement Technology and Process Control, University of Oulu
Contributors: Jeyhani, V., Vuorinen, T., Noponen, K., Mäntysalo, M., Vehkaoja, A.
Number of pages: 6
Pages: 1138-1143
Publication date: 2016

Host publication information

Title of host publication: XIV Mediterranean Conference on Medical and Biological Engineering and Computing 2016 : MEDICON 2016, March 31st-April 2nd 2016, Paphos, Cyprus
Publisher: Springer Verlag
ISBN (Print): 9783319327013

Publication series

Name: IFMBE Proceedings
Volume: 57
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: Electrode, Impedance, Location, Pneumography, Respiration

Bibliographical note

INT=ase,"Jeyhani, Vala"
JUFOID=58152

Source: Scopus
Source ID: 84968593202

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

Hydrolysis rates, methane production and nitrogen solubilisation of grey waste components during anaerobic degradation

Municipal grey waste (i.e. the remaining fraction in municipal waste management systems in which putrescibles (biowaste) and other recyclables (paper, metals, glass) are source-segregated) was manually sorted into six main fractions on the basis of composition and also separated by sieving (100 mm mesh size) into two fractions, oversized and undersized, respectively. In practice, in waste management plant the oversized fraction is (or will be) used to produce refuse-derived fuel and the undersized landfilled after biological stabilisation. The methane yields and nitrogen solubilisation of the grey waste and the different fractions (all studied samples were first milled to 5 mm particle samples) were determined in a 237-day methane production batch assay and in a water elution test, respectively. The grey waste was found to contained remnants of putrescibles and also a high amount of other biodegradable waste, including packaging, cartons and cardboard, newsprint, textiles and diapers. These waste fractions comprised 41%-w/w of the grey waste and produced 40-210 m3 methane (total solids (TS))-1 and less than 0.01 gNH4-NkgTS-1 added except diapers which produced 9.8 gNH4-N kgTS-1 added in the batch assays. In the case of the two sieved fractions and on mass bases, most of the methane originated from the oversized fraction, whereas most of the NH4-N was solublised from the undersized fraction. The first-order kinetic model described rather well the degradation of each grey waste fraction and component, showing the different components to be in the range 0.021-0.058 d-1, which was around one-sixth of the values reported for the source-segregated putrescible fraction of MSW.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: University of Jyväskylä, Jyväskylän yliopisto, Russian Academy of Sciences
Contributors: Jokela, J. P. Y., Vavilin, V. A., Rintala, J. A.
Number of pages: 8
Pages: 501-508
Publication date: Mar 2005
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 96
Issue number: 4
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2005): SJR 1.278 SNIP 1.99
Original language: English
ASJC Scopus subject areas: Agronomy and Crop Science, Food Science, Process Chemistry and Technology, Applied Microbiology and Biotechnology
Keywords: Anaerobic degradation, Components, Grey waste, Hydrolysis rate, Landfill, Methane, Municipal solid waste, Nitrogen, Solubilisation, Source-segregation
Source: Scopus
Source ID: 7544250470

Research output: Contribution to journalArticleScientificpeer-review

Nocturnal use of light compression garments and recovery

The aim of the study was to investigate nocturnal effect of wearing whole-body light compression garments on post-exercise recovery. HRV analysis was used to evaluate the recovery. The study involved sixteen female Finnish baseball players for four three-day-periods. The participants wore light compression garments every other three-day period and kept record of daily events. The analyzed period was 4 hours starting from the moment subjects fell asleep. The HRV analysis was performed for the time domain, frequency domain and nonlinear measurements. There were no statistical differences in HRV parameters between nights when subjects used or did not use light compression garments. This indicates that whole-body light compression garments had no benefits on the post-exercise recovery during the night.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Faculty of Biomedical Sciences and Engineering, Research group: Physiological Measurement Systems and Methods Group, BioMediTech
Contributors: Jokinen, V., Korpela, J., Lehtinen, E., Perttunen, J., Viik, J.
Number of pages: 4
Pages: 125-128
Publication date: 2018

Host publication information

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

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: Athletes, Autonomic nervous system, Heart rate variability, Light compression garments, Nocturnal recovery

Bibliographical note

INT=tut-bmt,"Jokinen, V.I."
jufoid=58152

Source: Scopus
Source ID: 85021718673

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

Dry electrode sizes in recording ECG and heart rate in wearable applications

The rise of wearable electronics is paving the way for textile integrated sensor applications. ECG and heart rate monitoring are common in health care and consumer applications, respectively. In short term monitoring Ag/AgCl, conductive polymer or fabric electrodes can be used. In long term monitoring the electrolyte and adhesives may cause skin irritation, therefore textile integrated skin friendly dry electrodes may be a solution. The electrodes need to be cost-effective, easy to integrate, need no special care from the user and perform well. Conductive polymer and textile used in sports applications perform poorly when used without electrolyte. Stainless steel is common, affordable, easy to process, biocompatible (selected alloys), and provides adequate ECG quality. In this paper, we study different size stainless steel dry electrodes in ECG and heart rate monitoring and compare those with commercial disposable Ag/AgCl electrodes. The results show that stainless steel dry electrodes performed well throughout the tested activities if the circular electrode diameter was 20 mm or larger.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electronics and Communications Engineering
Contributors: Joutsen, A. S., Kaappa, E. S., Karinsalo, T. J., Vanhala, J.
Number of pages: 4
Pages: 735-738
Publication date: 2018

Host publication information

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

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: Dry electrodes, ECG, Electrode size, Heart rate, Stainless steel

Bibliographical note

jufoid=58152

Source: Scopus
Source ID: 85021723087

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

Performance analysis of novel flexible electrodes for wearable ECG/heart rate monitoring

The development of manufacturing methods has made it possible to add metal materials as flexible electrodes into wearables. This paper presents effective methods of manufacturing custom electrodes that give reliable ECG/HR signal and maintain textile comfort. Screen-printing, micro etching and electro plating have been used to make dry electrodes that are integrated into common types of heart rate straps. Each manufacturing method of dry electrodes is related to single electrode material. The effects of different materials on signal quality are investigated. Tested materials were platinum, silver ink and stainless steel. These heart rate straps were used during rest condition, cycling, walking and running. Ten users were included (7 male and 3 female) and were measured during physical activity. Electrode performance was measured and signals were compared simultaneously with silver/silver chloride gel electrodes. In this study, platinum has the smallest signal error; therefore, it is the most appropriate of the tested materials. Followed by Ag ink, disposable Ag/AgCl and lastly stainless steel. The results obtained during exercise indicate that, all of the tested materials worked reliably with these activities and there is no statistical difference between them. The HR error % in all materials was below 20%, which was considered the limit for reliability. It can be concluded that their signal measurement reliability is adequate for sportswear and health care applications. These electrodes did not rub or the edges scratched the skin. The additional result is that they are reasonably comfortable to wear during exercising.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electronics and Communications Engineering, Research group: Personal Electronics Group
Contributors: Kaappa, E. S., Joutsen, A. S., Vanhala, J.
Number of pages: 4
Pages: 237-240
Publication date: 2018

Host publication information

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

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: Electro plating, Electrode, Micro etching, Screen print, Wearable

Bibliographical note

jufoid=58152

Source: Scopus
Source ID: 85021752411

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

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

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

Characterisation of novel regenerated cellulosic, viscose, and cotton fibres and the dyeing properties of fabrics

There is a global demand for constant increase in the production of textile fibres. Currently, the market for cellulosic fibres is dominated by cotton and viscose fibres. However, new alternative cellulosic fibres are being sought to meet the growing demand. The dyeing properties of novel fibres aiming at the marketplace are among the properties that determine their applicability to textiles. Recently, a novel process for producing cellulosic fibres, the Biocelsol process, has been scaled up so that the spinning of yarn from Biocelsol fibres is now possible. In this study, the reactive dye Levafix CA Blue was applied to cellulosic fabrics made from viscose, cotton, and Biocelsol yarns. The crystalline structure and morphology of the fibres were studied by Fourier transform infrared spectroscopy and field-emission scanning electron microscopy. The crystalline structure and morphology of the Biocelsol fibres resembled those of viscose fibres, but, owing to higher water absorption, the Biocelsol fabric had a higher dye exhaustion. The colour yield of the Biocelsol fabric was 62% and 41% higher than that of cotton and viscose fabrics respectively, suggesting that less dye is needed to gain a shade in Biocelsol fabric than in viscose and cotton fabrics.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Materials Science, Research group: Fibre Materials, Research group: Materials Characterization, Engineering materials science and solutions (EMASS)
Contributors: Kamppuri, T., Vehviläinen, M., Puolakka, A., Honkanen, M., Vippola, M., Rissanen, M.
Number of pages: 7
Pages: 396-402
Publication date: 2015
Peer-reviewed: Yes

Publication information

Journal: Coloration Technology
Volume: 131
Issue number: 5
ISSN (Print): 1472-3581
Ratings: 
  • Scopus rating (2015): CiteScore 2.2 SJR 0.425 SNIP 0.97
Original language: English
ASJC Scopus subject areas: Chemistry (miscellaneous), Chemical Engineering(all), Materials Science (miscellaneous)
Source: Scopus
Source ID: 84941940416

Research output: Contribution to journalArticleScientificpeer-review

Evaluation of crushing strength of spray-dried MgAl2O4 granule beds

The crushing strengths of four different experimental magnesium aluminate spinel (MgAl2O4) granule beds were monitored with the axial die pressing test after heat treatments. Precursor, magnesium hydroxide (Mg(OH)2) and magnesium oxide (MgO) as Mg precursor and aluminium oxide hydroxide Al(O)OH and α-Al2O3 as Al precursor, were used for experimental granules, which were manufactured via a dispersion manufacturing and spray-drying process. After spray-drying, granules were heat treated in air at 1000, 1100, 1200, 1300 and 1400 °C. In order to understand the potential effect of precursor, phase structure, morphology, particle size distribution and density of granules on crushing strength behaviour, scanning X-ray diffraction (XRD) was used together with electron microscopy (SEM) and laser diffraction (LDPA) for characterisation. All precursor mixtures formed spherical granules during the spray-drying process and pure spinel phase structure during heat treatment. The crushing strength test results indicated that the Al precursor clearly affected the crushing strength behaviour of experimental granule beds. The highest strength was observed for granule beds with Al(O)OH) as Al and Mg(OH)2 as Mg precursor.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Materials Science, Engineering materials science and solutions (EMASS), VTT Technical Research Centre of Finland
Contributors: Kanerva, U., Suhonen, T., Lagerbom, J., Levänen, E.
Number of pages: 7
Pages: 8494-8500
Publication date: 1 Aug 2015
Peer-reviewed: Yes

Publication information

Journal: Ceramics International
Volume: 41
Issue number: 7
ISSN (Print): 0272-8842
Ratings: 
  • Scopus rating (2015): CiteScore 4 SJR 0.823 SNIP 1.353
Original language: English
ASJC Scopus subject areas: Ceramics and Composites, Process Chemistry and Technology, Electronic, Optical and Magnetic Materials, Surfaces, Coatings and Films, Materials Chemistry
Keywords: Axial pressing, Granule, MgAl<inf>2</inf>O<inf>4</inf> spinel, The crushing strength

Bibliographical note

EXT="Lagerbom, Juha"
EXT="Kanerva, Ulla"

Source: Scopus
Source ID: 84929271760

Research output: Contribution to journalArticleScientificpeer-review

Surface science analysis and surface modification methods for biomaterials research

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Surface Science, Department of Physics, Department of Biomedical Engineering, University of Tampere Institute of Medical Technology, Department of Biomedical Engineering
Contributors: Kanninen, L., Jokinen, N., Lahtonen, K., Jussila, P., Ali-Löytty, H., Hirsimäki, M., Leppiniemi, J., Hytönen, V., Kulomaa, M., Ahola, N., Paakinaho, K., Kellomäki, M., Valden, M.
Number of pages: 1
Pages: 133
Publication date: 1 Jan 2010
Peer-reviewed: Yes

Publication information

Journal: European Cells and Materials
Volume: 20
Issue number: SUPPL. 3
ISSN (Print): 1473-2262
Ratings: 
  • Scopus rating (2010): SJR 0.192 SNIP 0.193
Original language: English
ASJC Scopus subject areas: Bioengineering, Biochemistry, Biomaterials, Biomedical Engineering, Cell Biology
Source: Scopus
Source ID: 84860892200

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

Effects of solid-liquid separation on recovering residual methane and nitrogen from digested dairy cow manure

The feasibility of optimizing methane and nitrogen recovery of samples obtained from farm biogas digester (35 °C) and post-storage tank (where digested material is stored for 9-12 months) was studied by separating the materials into different fractions using 2, 1, 0.5 and 0.25 mm sieves. Mass-balances revealed that digested material mainly consists of <0.25 mm (60-69%) and >2 mm (18-27%) fractions, while fractions between 2 and 0.25 mm made the rest. Incubation of solid fractions >0.25 mm of digester material at 35 °C resulted in specific methane yields of 0.060-0.085 m3 kg-1 volatile solids (VS) during initial 30-50 d and 0.16-0.18 m3 kg-1 VS at the end of 340 d incubation. Similarly, fractions >0.25 mm of post-storage tank material produced 0.055-0.092 m3 kg-1 VS and 0.13-0.16 m3 kg-1 VS of methane after 30-50 d and after 250 d, respectively. Methane yields for fractions <0.25 mm of post-storage tank was 0.03 m3 kg-1 VS after 30-50 d and 0.05 m3 kg-1 VS after 250 d compared to 0.20 m3 kg-1 VS and 0.41 m3 kg-1 VS, respectively for the same fraction of digester material. Separation of digested cow manure into solids and liquid fractions to recover methane may be feasible only for post-storage tank material and not for digester material. Nitrogen management would not be feasible with neither material as total nitrogen and ammonium-nitrogen concentrations were equally distributed among the segregated fractions.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Jyväskylän yliopisto, University of Jyväskylä
Contributors: Kaparaju, P. L. N., Rintala, J. A.
Number of pages: 8
Pages: 120-127
Publication date: Jan 2008
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 99
Issue number: 1
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2008): SJR 1.736 SNIP 2.724
Original language: English
ASJC Scopus subject areas: Agronomy and Crop Science, Food Science, Process Chemistry and Technology, Applied Microbiology and Biotechnology, Bioengineering, Environmental Engineering, Waste Management and Disposal
Keywords: Anaerobic digestion, Digested material, Farm-scale digester, Fractionation, Methane, Post-storage tank
Source: Scopus
Source ID: 34848884581

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

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

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

Enqueˆte de la variabilit´ cycle-`-cycle du NO dans la combustion homog`ne

Cyclic variability of spark ignition engines is recognized as a scatter in the combustion parameter recordings during actual operation in steady state conditions. Combustion variability may occur due to fluctuations in both early flame kernel development and in turbulent flame propagation with an impact on fuel consumption and emissions. In this study, a detailed chemistry model for the prediction of NO formation in homogeneous engine conditions is presented. The Wiebe parameterization is used for the prediction of heat release; then the calculated thermodynamic data are fed into the chemistry model to predict NO evolution at each degree of crank angle. Experimental data obtained from literature studies were used to validate the mean NO levels calculated. Then the model was applied to predict the impact of cyclic variability on mean NO and the amplitude of its variation. The cyclic variability was simulated by introducing random perturbations, which followed a normal distribution, to the Wiebe function parameters. The results of this approach show that the model proposed better predicts mean NO formation than earlier methods. Also, it shows that to the non linear formation rate of NO with temperature, cycle-to-cycle variation leads to higher mean NO emission levels than what one would predict without taking cyclic variation into account.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Urban circular bioeconomy (UrCirBio), Aristotle University of Thessaloniki, Laboratory of Applied Thermodynamics
Contributors: Karvountzis-Kontakiotis, A., Ntziachristos, L.
Number of pages: 13
Pages: 111-123
Publication date: 2015
Peer-reviewed: Yes

Publication information

Journal: OIL AND GAS SCIENCE AND TECHNOLOGY : REVUE DE L'INSTITUT FRANCAIS DU PETROLE
Volume: 70
Issue number: 1
ISSN (Print): 1294-4475
Ratings: 
  • Scopus rating (2015): CiteScore 2.1 SJR 0.361 SNIP 0.733
Original language: French
ASJC Scopus subject areas: Chemical Engineering(all), Fuel Technology, Energy Engineering and Power Technology
Source: Scopus
Source ID: 84924341440

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

Modular Instrumentation for Controlling and Monitoring In-Vitro Cultivation Environment and Image-based Functionality Measurements of Human Stem Cells

Artificial animal cell culture was successfully developed by Ross Harrison in 1907. But it was not until the 1940’s and 1950’s that several developments occurred, which expedited the cell culturing in-vitro (C-Vitro) to be a consistent and reproducible technique to study isolated living-cells in a controlled environment. Currently, CVitro is one of the major tools in cellular and molecular biology both in the academia and industry. They are extensively utilised to study the cellular physiology/biochemistry, to screen drugs/therapeutic compounds, to understand the effects of drugs/toxic compounds and also to identify the pathways of carcinogenesis/mutagenesis. It is also used in large scale manufacturing of vaccines and therapeutic proteins. In any experimental setup, it is important that the C-Vitro model should represent the physiological phenomena of interest with reasonable accuracy so that all experimental results are statistically consistent and reproducible. In this direction, sensors and measurement systems play important roles in in-situ detection and/or control/manipulation of cells/tissues/environment. This thesis aimed to develop new technology for tailored cell culturing and integrated measurements. Firstly, design and assembly of a portable Invert-upright microscope interchangeable modular cell culturing platform (iuCMP) was envisioned. In contrast to conventional methods, micro-scaled systems mimic the cells' natural microenvironment more precisely, facilitating accurate and tractable models. The iuCMP integrates modular measurement schemes with a mini culture chamber using biocompatible cell-friendly materials, automated environment-control (temperature and gas concentrations), oxygen sensing and simultaneous functional measurements (electrophysiological and image-based). Time lapse microscopy is very useful in cell biology, but integration of advanced >i>in-vitro/device based biological systems (e.g. lab/organ/body-on-chips, or mini-bioreactors/microfluidic systems) into conventional microscopes can be challenging in several circumstances due to multiple reasons. But in iuCMP the main advantage is, the microscope can be switched either as an inverted or as an upright system and therefore can accommodate virtually any in-vitro device. It can capture images from regions that are otherwise inaccessible by conventional microscopes, for example, cells cultured on physical or biochemical sensor systems. The modular design also allows accommodating more sensor or measurement systems quite freely. We have demonstrated the system for video-based beating analysis of cardiomyocytes, cell orientation analysis on nanocellulose, and simultaneous long-term in-situ microscopy with oxygen and temperature sensing in hypoxia.

In an example application, the system was utilised for long-term temperature stressing and simultaneous mechanobiological analysis of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). For this the iuCMP together with a temperature sensor plate (TSP) and a novel non-invasive beating analysis software (CMaN—cardiomyocyte function analysis tool, scripted as a subpart of this thesis), was applied for automated temperature response studies in hiPSC-CM cultures. In-situ temperature sensing is usually challenging with bulky external sensors, but TSPs solved this issue. In the temperature response study, we showed that the relationship between hiPSC-CM beating frequency and temperature is non-linear and measured the Q10 temperature coefficients. Moreover, we observed the hiPSC-CM contractile networking, including propagation of the action potential signal between dissociated clusters and their non-invasive measurements. It was the first case where these events were reported in hiPSC-CM clusters and their noninvasive measurements by image processing.

The software CMaN comes with a user-friendly interface and, is equipped with features for batch processing, movement centre detection and cluster finding. It can extract six different signals of the contractile motion of cardiomyocytes (clusters or single cells) per processing. This ensures a minimum of one useful beating signal even in the cases of complex beating videos. On the processing end, compared to similar tools, CMaN is faster, more sensitive, and computationally less expensive and allows ROI based processing. In the case of healthy cells, the waveform of the signal from the CMaN resembles an ECG signal with positive and negative segments, allowing the computation of contraction and relaxation features separately.

In addition to iuCMP, a Modular optical pH measurement system (MO-pH) for 24/7 non-contact cell culture measurements was also developed. The MO-pH incorporates modular sterilisable optical parts and is used in phenol-red medium cell cultures. The modular assembly of MO-pH cassettes is unique and reusable. Measurements are carried out in a closed flow system without wasting any culture medium and requires no special manual attention or recalibrations during culture. Furthermore, a new absorption correction model was put forward that minimised errors caused e.g. by biolayers in spectrometric pH measurement, which improved the pH measurement accuracy. MO-pH has been applied in long-term human adipose stem cells (hASC) expansion cultures in CO2 dependent and independent media. Additionally, the MO-pH was also utilised to comprehend the behaviour of pH, temperature and humidity in water jacked incubators as well as to record the pH response as a function of temperature in the presence and absence of CO2 in the context of stem cell cultures. The resulting plots clearly showed the interplay between measured parameters indicating a few stress sources present all through the culture. Additionally, it provided an overall picture of behaviour of critical control parameters in an incubator and pointed out the need for bioprocess systems with automatic process monitoring and smart control for maximum yield, optimal growth and maintenance of the cells. Besides, we also integrated MO-pH into flasks with reclosable lids (RL-F) and tested its applicability in stem cell cultures. A standalone system around an RL-F flask was built by combining the cell culture, medium perfusion and optical measurements. The developed RL-F system has been successfully tested in ASC-differentiation cultures.

Finally, a few trial experiments for image-based pH estimation aimed for iuCMP have also been carried out. This includes tests with LCD illumination, optical projection tomography, and webcam systems. In reality, the pH is not distributed uniformly in tissues, and has shown a gradient of up to 1.0 pH unit within 1 cm distance. Therefore, producing reliable pH maps also in in-vitro can be important in understanding various common pathologies and location of lesions. A reliable and adequately developed long-term pH mapping method will be an important addition into the iuCMP.

General information

Publication status: Published
MoE publication type: G5 Doctoral dissertation (article)
Organisations: BioMediTech, Research group: Sensor Technology and Biomeasurements (STB)
Contributors: Kattipparambil Rajan, D.
Publication date: 27 May 2020

Publication information

Publisher: Tampere University
Volume: 256
ISBN (Print): 978-952-03-1568-9
ISBN (Electronic): 978-952-03-1569-6
Original language: English

Publication series

Name: Tampere University Dissertations
Volume: 256
ISSN (Print): 2489-9860
ISSN (Electronic): 2490-0028
ASJC Scopus subject areas: Cardiology and Cardiovascular Medicine, Biomedical Engineering, Bioengineering

Research output: Book/ReportDoctoral thesisCollection of Articles

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

Sorption and retention of ethylene glycol monoethyl ether (EGME) on silicas

Sorption of ethylene glycol monoethyl ether (EGME) was studied gravimetrically and correlated with the results of retention experiments where samples wetted with EGME were evacuated. If a sorption measurement is done conventionally by increasing the vapor pressure slowly by small steps, molecules are packed smoothly along the surface, and a fairly flat isotherm is obtained. If the sample is directly exposed to a high vapor pressure or the normal sorption mode is disturbed by directly reducing the pressure, more EGME is sorbed. Then some of the molecules may be fixed only at their hydroxy ends. The evacuation curves are best interpreted in a semilogarithmic form, by which the value of the monolayer capacity can be estimated. EGME can be used for surface area measurements of silicas, but with porous samples areas that are too large are probably obtained. When EGME is packed smoothly on standard silica TK 800, one molecule occupies an area of 0.44 nm2, computed by the BET equation with three parameters, or 1 mg of EGME covers 3.0 m2.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Rakennetekniikka, Tampere University of Technology, University of Tampere
Contributors: Kellomäki, A., Kuula-Väisänen, P., Nieminen, P.
Number of pages: 6
Pages: 373-378
Publication date: 1989
Peer-reviewed: Yes

Publication information

Journal: Journal of Colloid and Interface Science
Volume: 129
Issue number: 2
ISSN (Print): 0021-9797
Original language: English
ASJC Scopus subject areas: Colloid and Surface Chemistry, Physical and Theoretical Chemistry, Surfaces and Interfaces
Source: Scopus
Source ID: 45149145866

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

Fabrication of ssDNA/oligo(ethylene glycol) monolayers and complex nanostructures by an irradiation-promoted exchange reaction

Creative design: An approach to preparing mixed monolayers of thiolated single-stranded DNA (ssDNA) and oligo(ethylene glycol)s (OEG-AT) in a broad range of compositions as well as ssDNA/OEG-AT patterns of any required shape (see top figure) has been shown. A combination of this approach with surface-initiated enzymatic polymerization allows complex 3D DNA nanostructures to be sculpted with high spatial precision (bottom).

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Integrated Technologies for Tissue Engineering Research (ITTE), Universitat Heidelberg, Duke University
Contributors: Khan, M. N., Tjong, V., Chilkoti, A., Zharnikov, M.
Number of pages: 4
Pages: 10303-10306
Publication date: 8 Oct 2012
Peer-reviewed: Yes

Publication information

Journal: Angewandte Chemie (International Edition)
Volume: 51
Issue number: 41
ISSN (Print): 1433-7851
Ratings: 
  • Scopus rating (2012): CiteScore 16.5 SJR 6.407 SNIP 2.329
Original language: English
ASJC Scopus subject areas: Chemistry(all), Catalysis
Keywords: chemical lithography, DNA structures, monolayers, nanostructures, polymer brushes
Source: Scopus
Source ID: 84867091572

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

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

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

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

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

Workplace performance of a loose-fitting powered air purifying respirator during nanoparticle synthesis

Nanoparticle (particles with diameter ≤100 nm) exposure is recognized as a potentially harmful size fraction for pulmonary particle exposure. During nanoparticle synthesis, the number concentrations in the process room may exceed 10 × 10<sup>6</sup> cm<sup>−3</sup>. During such conditions, it is essential that the occupants in the room wear highly reliable high-performance respirators to prevent inhalation exposure. Here we have studied the in-use program protection factor (PPF) of loose-fitting powered air purifying respirators, while workers were coating components with TiO<inf>2</inf> or Cu<inf>x</inf>O<inf>y</inf> nanoparticles under a hood using a liquid flame spray process. The PPF was measured using condensation particle counters, an electrical low pressure impactor, and diffusion chargers. The room particle concentrations varied from 4 × 10<sup>6</sup> to 40 × 10<sup>6</sup> cm<sup>−3</sup>, and the count median aerodynamic diameter ranged from 32 to 180 nm. Concentrations inside the respirator varied from 0.7 to 7.2 cm<sup>−3</sup>. However, on average, tidal breathing was assumed to increase the respirator concentration by 2.3 cm<sup>−3</sup>. The derived PPF exceeded 1.1 × 10<sup>6</sup>, which is more than 40 × 10<sup>3</sup> times the respirator assigned protection factor. We were unable to measure clear differences in the PPF of respirators with old and new filters, among two male and one female user, or assess most penetrating particle size. This study shows that the loose-fitting powered air purifying respirator provides very efficient protection against nanoparticle inhalation exposure if used properly.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Physics, Research group: Aerosol Synthesis, National Research Centre for the Working Environment, Finnish Institute of Occupational Health, Helsinki University, TNO
Contributors: Koivisto, A. J., Aromaa, M., Koponen, I. K., Fransman, W., Jensen, K. A., Mäkelä, J. M., Hämeri, K. J.
Publication date: 9 Apr 2015
Peer-reviewed: Yes

Publication information

Journal: Journal of Nanoparticle Research
Volume: 17
Issue number: 4
ISSN (Print): 1388-0764
Ratings: 
  • Scopus rating (2015): CiteScore 3.8 SJR 0.568 SNIP 0.725
Original language: English
ASJC Scopus subject areas: Atomic and Molecular Physics, and Optics, Condensed Matter Physics, Modelling and Simulation, Chemistry(all), Materials Science(all), Bioengineering
Keywords: Aerosol, Air purifying respirator, Filtration, Occupational safety, Protection factor, Respirator performance

Bibliographical note

EXT="Koivisto, Antti J."

Source: Scopus
Source ID: 84927730047

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

Texture-property relations of bioamine crosslinked gellan gum hydrogels

Gellan gum is a hydrogel with potential for soft tissue engineering but a quick and thorough method is needed for screening of different possible compositions for more extensive studies. Here optical projection tomography in bright field mode was used to image nearly transparent hydrogels to record their optical texture in 3D. The gained Haralick’s textural features were then analyzed with multiple discriminant analysis and combined with data from mechanical testing and neuronal cell culturing. We show the usefulness of optical texture analysis in screening of hydrogel compositions when aiming for tissue engineering applications.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: BioMediTech, Faculty of Biomedical Sciences and Engineering, Research group: Biomaterials and Tissue Engineering Group, Facilities and Infrastructure, Research group: Computational Biophysics and Imaging Group
Contributors: Koivisto, J., Koskela, O., Montonen, T., Parraga, J. E., Joki, T., Ylä-Outinen, L., Narkilahti, S., Figueiras, E., Hyttinen, J., Kellomäki, M.
Number of pages: 4
Pages: 189-192
Publication date: 2018

Host publication information

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

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: Gellan gum, Haralick’s textural features, Hydrogel, Neuron, Optical projection tomography

Bibliographical note

jufoid=58152

Source: Scopus
Source ID: 85021715316

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

Addressing closed-chain dynamics for high-precision control of hydraulic cylinder actuated manipulators

Nonlinear model-based (NMB) control methods have been shown (both in theory and in practice) to provide the most advanced control performance for highly nonlinear hydraulic manipulators. In these methods, the inverse dynamics of a system are used to proactively generate the system actuation forces from the desired motion dynamics. To model the inverse dynamics in articulated systems, the Lagrange dynamics and the Newton- Euler dynamics are the most common methods. In hydraulic cylinder actuated manipulators, a linear motion of the cylinder can be converted to a rotational joint motion between two links, creating closed-chain structures in the system. In Lagrange-dynamics-based control methods, the closed-chain structures are typically treated as an open-chain structure, which may raise the question of inaccurate system modeling. Contrary, the virtual decomposition control (VDC) approach is the first rigorous NMB control method to take full advantage of Newton- Euler dynamics, allowing to address the system nonlinear dynamics without imposing additional approximations. In VDC, the actuated closed-chain structures can be virtually decomposed to open chain structures. To address the dynamics between the decomposed open chains, three specific terms (namely two load distribution factors and an internal force vector) need to be addressed. However, analytical solutions for these terms cannot be found in the literature. This paper provides the detailed solutions for these terms, which are further needed in a high-precision control of hydraulic robotic manipulators.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Automation and Hydraulic Engineering, Research group: Innovative Hydraulic Automation, Canadian Space Agency
Contributors: Koivumäki, J., Zhu, W. H., Mattila, J.
Publication date: 2018

Host publication information

Title of host publication: BATH/ASME 2018 Symposium on Fluid Power and Motion Control, FPMC 2018
Publisher: ASME
ISBN (Electronic): 9780791851968
ASJC Scopus subject areas: Fluid Flow and Transfer Processes, Control and Systems Engineering
Source: Scopus
Source ID: 85058051592

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

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

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

General information

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

Publication information

Journal: Bioresource Technology
Volume: 258
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2018): CiteScore 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: Bioelectrochemical system, Exoelectrogen, Microbial community, Wastewater
Source: Scopus
Source ID: 85043472557

Research output: Contribution to journalReview ArticleScientificpeer-review

Low-latency EMG onset and termination detection for facial pacing

An adaptive method for reliable and fast detection of muscle activity from surface electromyographic (sEMG) signals is introduced. The aim of this research was to minimize the delay of the onset and termination detection, while still retaining the reliability and simplicity of the detection algorithm. The proposed algorithm is based on a double-threshold detector. The algorithm applies the same principles as a constant false alarm rate (CFAR) processor that is often used to distinguish events from noisy environments with dynamic noise characteristics. The algorithm was tested with different noise conditions and frequencies. For each condition, a set of 1000 computer-simulated EMG signals were processed multiple times with different processing parameters in order to find the optimal settings for reliable muscle activity detection. The results for the detection delays were comparable to previously published results, and for low-noise conditions the detection worked without errors. The performance of the algorithm was verified using real sEMG signals. Performance in termination detection that has often been neglected in prior studies, is also reported. The results show that the method could be applied in the targeted real-time application: facial pacing.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: BioMediTech, Faculty of Biomedical Sciences and Engineering, Research area: Microsystems, Research group: Sensor Technology and Biomeasurements (STB), Department of Clinical Neurophysiology, Pirkanmaan sairaanhoitopiiri, Faculty of Medicine and Life Sciences (Otorhinolaryngology),
Contributors: Kontunen, A., Rantanen, V., Vehkaoja, A., Ilves, M., Lylykangas, J., Mäkelä, E., Rautiainen, M., Surakka, V., Lekkala, J.
Number of pages: 4
Pages: 1016-1019
Publication date: 2018

Host publication information

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

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: Double threshold detector, Electromyography, Facial pacing
Electronic versions: 
URLs: 

Bibliographical note

jufoid=58152

Source: Scopus
Source ID: 85021753090

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

A simulation case study of production planning and control in printed wiring board manufacturing

Production planning and control in printed wiring board (PWB) manufacturing is becoming more difficult as PWB's technology is developing and the production routings become more complex. Simultaneously, the strategic importance of delivery accuracy, short delivery times, and production flexibility is increasing with the highly fluctuating demand and short product life cycles of end products. New principles, that minimize throughput time while guaranteering excellent customer service and adequate capacity utilization, are needed for production planning and control. Simulation is needed in order to develop the new principles and test their superiority. This paper presents an ongoing simulation product that aims at developing the production planning and control of a PWB manufacturer. In the project, a discrete event simulation model is built of a pilot case factory. The model is used for comparing the effect of scheduling, queuing rules, buffer policies, and lot sizes on customer service and cost efficiency.

General information

Publication status: Published
MoE publication type: Not Eligible
Organisations: Industrial Engineering and Management, Aalto University, TAI Research Centre
Contributors: Korhonen, H. M. E., Heikkilä, J., Törnwall, J. M.
Number of pages: 4
Pages: 844-847
Publication date: 1 Dec 2001
Peer-reviewed: Yes

Publication information

Journal: Winter Simulation Conference Proceedings
Volume: 2
ISSN (Print): 0275-0708
Ratings: 
  • Scopus rating (2001): SJR 0.377
Original language: English
ASJC Scopus subject areas: Chemical Health and Safety, Software, Safety, Risk, Reliability and Quality, Applied Mathematics, Modelling and Simulation
Source: Scopus
Source ID: 0035708229

Research output: Contribution to journalConference articleScientificpeer-review

Characterization of chloride channels in human embryonic stem cell derived retinal pigment epithelium

Retinal pigment epithelium (RPE) is vital for vision. Its ion channels play important roles in the various functions of RPE that are critical for retinal welfare. These functions are often disrupted in degenerative eye diseases leading to visual impairment and even blindness. New treatments are currently being developed and transplantation of human embryonic stem cell (hESC)-derived RPE is showing great promise. For the success of these therapies, functionality of the transplantable cells needs to be verified. Presence of ion channels in hESC-derived RPE remains poorly known, particularly regarding the various chloride (Cl-) channels. We addressed this issue by investigating the Cl- conductivity of hESC-derived RPE by whole-cell patch clamp recordings followed by immunolabeling of the Cl- channels typical to RPE. Our recordings showed a diverse pattern of slowly inactivating currents characteristic to voltage-dependent Cl- channels (ClC) previously reported for RPE. Some of the identified currents were modulated by changes in intracellular calcium concentration. This data, together with the immunolabeling, demonstrated the presence of bestrophin-1, cystic fibrosis transmembrane regulator (CFTR) and ClC-2 channels in hESC-derived RPE thus indicating their capability to mimic native Cl- physiology.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Faculty of Biomedical Sciences and Engineering, Research group: Computational Biophysics and Imaging Group, BioMediTech
Contributors: Korkka, I., Johansson, J. K., Skottman, H., Hyttinen, J., Nymark, S.
Number of pages: 4
Pages: 454-457
Publication date: 2018

Host publication information

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

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: Chloride channels, Human embryonic stem cells, Immunolabeling, Patch clamp, Retinal pigment epithelium

Bibliographical note

jufoid=58152

Source: Scopus
Source ID: 85021731884

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

Light-fuelled transport of large dendrimers and proteins

This work presents a facile water-based supramolecular approach for light-induced surface patterning. The method is based upon azobenzene- functionalized high-molecular weight triazine dendrimers up to generation 9, demonstrating that even very large globular supramolecular complexes can be made to move in response to light. We also demonstrate light-fuelled macroscopic movements in native biomolecules, showing that complexes of apoferritin protein and azobenzene can effectively form light-induced surface patterns. Fundamentally, the results establish that thin films comprising both flexible and rigid globular particles of large diameter can be moved with light, whereas the presented material concepts offer new possibilities for the yet marginally explored biological applications of azobenzene surface patterning.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Frontier Photonics, COMP Centre of Excellence, Department of Applied Physics, Aalto University, Aalto University, Texas Christian University
Contributors: Koskela, J. E., Liljeström, V., Lim, J., Simanek, E. E., Ras, R. H. A., Priimagi, A., Kostiainen, M. A.
Number of pages: 4
Pages: 6850-6853
Publication date: 14 May 2014
Peer-reviewed: Yes

Publication information

Journal: Journal of the American Chemical Society
Volume: 136
Issue number: 19
ISSN (Print): 0002-7863
Ratings: 
  • Scopus rating (2014): CiteScore 20.9 SJR 6.294 SNIP 2.573
Original language: English
ASJC Scopus subject areas: Chemistry(all), Catalysis, Biochemistry, Colloid and Surface Chemistry, Medicine(all)
Source: Scopus
Source ID: 84900818359

Research output: Contribution to journalArticleScientificpeer-review

Computational model for multifocal imaging in optical projection tomography and numerical analysis of all-in-focus fusion in tomographic image reconstruction

Optical projection tomography (OPT) is a noninvasive 3D imaging method that has been used to study small biological samples. In OPT samples can be mounted in hydrogel scaffold mimicking real life extracellular matrix, and hence grown in all natural dimensions. In optical imaging systems, focusing lenses are required for image acquisition. Due to these lenses, particles at a certain distance from objectives — in the focal plane of the lens — are captured accurately and the further a particle is from the focal plane the blurrier it is captured in the resulting image. To compensate this limitation, multifocal OPT is implemented, where images from each angle are taken with multiple focal planes at different distances. From these images, parts in focus are detected and combined into a single image using all-in-focus fusion algorithm. In this work we present computational way of modeling multifocal imaging and use the presented model to assess the performance of two different all-in-focus fusion methods.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Faculty of Biomedical Sciences and Engineering, Mathematics, Research group: Inverse Problems, Research group: Computational Biophysics and Imaging Group, BioMediTech, International Iberian Nanotechnology Laboratory
Contributors: Koskela, O., Pursiainen, S., Belay, B., Montonen, T., Figueiras, E., Hyttinen, J.
Number of pages: 4
Pages: 282-285
Publication date: 2018

Host publication information

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

Publication series

Name: IFMBE Proceedings
Volume: 65
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Biomedical Engineering, Bioengineering
Keywords: All-in-focus fusion, Multifocal microscopy, Optical 3D microscopy, Optical projection tomography, Tomographic image reconstruction
Electronic versions: 

Bibliographical note

jufoid=58152

Source: Scopus
Source ID: 85021750721

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

Finite element mapping for efficient image reconstruction in rotational electrical impedance tomography

Electrical impedance tomography (EIT) is a label free harmless imaging method capable of imaging differences in electrical conductivity of a sample. In EIT, a low frequency current is injected into the sample, voltage differences on sample surface are measured, and from these measurements, interior conductivity distribution is reconstructed. To increase the accuracy of reconstruction, rotational EIT (rEIT) has been proposed where independent measurements are taken from multiple rotational positions around the sample. However, the benefit of conventional electrode configurations are limited to small number of rotational positions. We have presented an approach called Limited Angle Full Revolution rEIT (LAFR-rEIT) that uses a small number of electrodes and large number of rotational measurement position measurements over 360°. The results are comparable to previous rotational EIT implementations, and furthermore, the limited EIT boundary access provides space for simultaneous attachment of other measurement modalities. On the other hand, the increased number of measurement positions cause an increase in computational complexity, and optimization is required until 3D applications are feasible. This work presents modifications into finite element mesh presentation of the imaging domain and outlines an optimization, that enables sufficiently light rotation for 3D LAFR-rEIT computations.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Faculty of Biomedical Sciences and Engineering, Research group: Computational Biophysics and Imaging Group, Ita-Suomen yliopisto, INL - International Iberian Nanotechnology
Contributors: Koskela, O., Lehti-Polojärvi, M., Seppänen, A., Figueiras, E., Hyttinen, J.
Number of pages: 4
Pages: 901-904
Publication date: 2018

Host publication information

Title of host publication: World Congress on Medical Physics and Biomedical Engineering 2018
Volume: 2
Publisher: Springer
ISBN (Print): 978-981-10-9037-0
ISBN (Electronic): 978-981-10-9038-7

Publication series

Name: IFMBE Proceedings
Volume: 68
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Bioengineering, Biomedical Engineering
Keywords: Finite element mesh, Multimodal imaging, Rotational electrical impedance tomography

Bibliographical note

jufoid=58152

Source: Scopus
Source ID: 85048211497

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

Impact of biodiesel application at various blending ratios on passenger cars of different fueling technologies

The effect of biodiesel on emissions of diesel passenger cars is a combination of the fuel properties, the blending ratio, and the vehicle technology. In this study, saturated and unsaturated biodiesel fuels were tested neat (B100) and in 30% blend with fossil diesel (B30) on two Euro 3 diesel passenger cars of different engine technologies, namely common rail and unit injector. The measured dataset is enlarged by introducing B10 results from an earlier study [15] in order to produce generalized conclusions over a wider range of blends. None of these vehicles was equipped with a particle filter and different conclusions might be reached for filter-equipped vehicles. The results indicate that the influence of biodiesel on pollutant emissions primarily depends on the blending ratio and secondly on the level of unsaturation and engine technology. Tailpipe CO 2, NO x and PM emissions with biodiesel varied from -1% to +3%, -1% to 14%, and -18% to -35%, respectively, compared to fossil diesel. The difference over fossil diesel generally increased with an increasing blending ratio. CO and HC emissions increased over the fossil diesel but remained at low levels and did not threaten the compliance of the vehicles with their respective emission limits. Use of biodiesel on the common rail vehicle led to a smaller NO x increase and a higher PM reduction than in the unit-injector case. The unsaturated fuel generally led to higher NO x emissions from both engine technologies. However, the maximum blending ratio of saturated biodiesel is limited to around B30 due to cold-flow limitations. Hence, the saturated vs. unsaturated species ratio should be carefully designed in market fuels in order to optimize environmental and operational benefits. Overall, it appears that blends up to 10% v/v may be introduced with limited urban air quality implications.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Urban circular bioeconomy (UrCirBio), Aristotle University of Thessaloniki, Laboratory of Applied Thermodynamics, European Commission-JRC
Contributors: Kousoulidou, M., Ntziachristos, L., Fontaras, G., Martini, G., Dilara, P., Samaras, Z.
Number of pages: 7
Pages: 88-94
Publication date: Aug 2012
Peer-reviewed: Yes

Publication information

Journal: Fuel
Volume: 98
ISSN (Print): 0016-2361
Ratings: 
  • Scopus rating (2012): CiteScore 5.6 SJR 1.813 SNIP 2.387
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Fuel Technology, Energy Engineering and Power Technology, Organic Chemistry
Keywords: Biodiesel, Fuel injection technology, Unsaturation level, Vehicle emissions
Source: Scopus
Source ID: 84861986728

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

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

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

A 'clusters-in-liquid' method for calculating infrared spectra identifies the proton-transfer mode in acidic aqueous solutions

In liquid water the transfer of an excess proton between two water molecules occurs through the Zundel cation, H 2 O···H + ···OH 2. The proton-transfer mode is the asymmetric stretch of the central O···H + ···O moiety, but there is no consensus on its identification in the infrared spectra of acidic aqueous solutions. Also, in experiments with protonated gas-phase water clusters, its position shifts with cluster size, which makes its relationship with solution spectra unclear. Here we introduce a 'clusters-in-liquid' approach for calculating the infrared spectrum from any set of charges, even single protons. We apply this procedure to multistate empirical valence-bond trajectories of protonated liquid water and to ab initio molecular dynamics of the protonated water dimer and hexamer in the gas phase. The calculated proton-transfer mode is manifested in both systems as a peak near 1,740% cm -1, in quantitative agreement with a band of similar frequency in the experimental infrared spectrum of protonated water clusters.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Computational Science X (CompX), Tallinn Technical University, Institute of Chemistry, Hebrew University of Jerusalem
Contributors: Kulig, W., Agmon, N.
Number of pages: 7
Pages: 29-35
Publication date: Jan 2013
Peer-reviewed: Yes

Publication information

Journal: Nature Chemistry
Volume: 5
Issue number: 1
ISSN (Print): 1755-4330
Ratings: 
  • Scopus rating (2013): CiteScore 28.8 SJR 8.691 SNIP 3.664
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all)
Source: Scopus
Source ID: 84871565081

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

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

Molecular engineering of avidin and hydrophobin for functional self-assembling interfaces

Control over the functionality of interfaces through biomolecular engineering is a central tool for nanoscale technology as well as many current applications of biology. In this work we designed fusion proteins that combined the surface adhesion and interfacial activity of a hydrophobin-protein together with the high affinity biotin-binding capability of an avidin-protein. We found that an overall architecture that was based on a circularly permuted version of avidin, dual-chain avidin, and hydrophobin gave a highly functional combination. The protein was produced in the filamentous fungus Trichoderma reesei and was efficiently purified using an aqueous two-phase partitioning procedure. The surface adhesive properties were widely different compared to wild-type avidin. Functional characterization showed that the protein assembled on hydrophobic surfaces as a thin layer even at very low concentrations and efficiently bound a biotinylated compound. The work shows how the challenge of creating a fusion protein with proteins that form multimers can be solved by structural design and how protein self-assembly can be used to efficiently functionalize interfaces.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Multi-scaled biodata analysis and modelling (MultiBAM), VTT Technical Research Centre of Finland, Fimlab Laboratories Ltd, Tampere University Hospital, Aalto University
Contributors: Kurppa, K., Hytönen, V. P., Nakari-Setälä, T., Kulomaa, M. S., Linder, M. B.
Number of pages: 8
Pages: 102-109
Publication date: 1 Aug 2014
Peer-reviewed: Yes

Publication information

Journal: Colloids and Surfaces B: Biointerfaces
Volume: 120
ISSN (Print): 0927-7765
Ratings: 
  • Scopus rating (2014): CiteScore 6.8 SJR 1.21 SNIP 1.565
Original language: English
ASJC Scopus subject areas: Surfaces and Interfaces, Biotechnology, Colloid and Surface Chemistry, Physical and Theoretical Chemistry, Medicine(all)
Keywords: Avidin, Biofunctional surface, Hydrophobin, Nanomaterial, Protein engineering
Source: Scopus
Source ID: 84901790623

Research output: Contribution to journalArticleScientificpeer-review

Tampere University of Technology, laboratory of materials science, paper converting and packaging technology Tampere, Finland

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Materials Science, Research group: Paper Converting and Packaging
Contributors: Kuusipalo, J., Lahti, J.
Number of pages: 1
Publication date: 1 Jan 2017

Host publication information

Title of host publication: 16th TAPPI European PLACE Conference 2017 : Basel; Switzerland; 22 May 2017 through 24 May 2017
Volume: May-2017
Publisher: TAPPI Press
ISBN (Electronic): 9781510850880
ASJC Scopus subject areas: Media Technology, Chemical Engineering(all), Chemistry(all), Mechanical Engineering, Materials Science(all)
Source: Scopus
Source ID: 85044476202

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

Improving the effect of nanoscale barrier coating on BOPP film properties: Influence of substrate contamination, web handling and pretreatments

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Department of Materials Science, Research group: Paper Converting and Packaging, Engineering materials science and solutions (EMASS), Lappeenranta University of Technology, ASTRaL, Miktech Oy, Masaryk Univ, Masaryk University Brno, R&D Ctr Low Cost Plasma & Nanotechnol Surface Mod
Contributors: Lahti, J., Johansson, P., Lahtinen, K., Cameron, D. C., Seppänen, T.
Number of pages: 23
Pages: 1039-1061
Publication date: 2014

Host publication information

Title of host publication: TAPPI PLACE Conference 2014
Volume: 2
Publisher: TAPPI Press
ISBN (Print): 9781510801271
ASJC Scopus subject areas: Materials Science(all), Chemistry(all), Mechanical Engineering, Media Technology, Chemical Engineering(all)
Source: Scopus
Source ID: 84939521131

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

Nanoscale barrier coating on BOPP packaging film by ALD

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Department of Materials Science, Research group: Paper Converting and Packaging
Contributors: Lahti, J.
Number of pages: 13
Pages: 493-505
Publication date: 2016

Host publication information

Title of host publication: TAPPI PLACE Conference 2016: Exploring New Frontiers
Publisher: TAPPI Press
ISBN (Electronic): 9781510823563
ASJC Scopus subject areas: Media Technology, Mechanical Engineering, Materials Science(all), Chemistry(all), Chemical Engineering(all)
Source: Scopus
Source ID: 84981736600

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

The effects of corona and flame treatment: Part 2. PE-HD and PP coated papers

The most important function of a packaging material is to shield the product inside the package. Extrusion coated papers and paperboards are generally used in various consumer packages like food, medical and cosmetic packages. Extrusion coatings give a barrier against water, water vapour, aroma, grease, oxygen, etc. In addition to barrier properties, heat sealability and printability are important properties in packaging applications. From the point of view of printing, the dense and impervious structure of extrusion coatings is challenging: printing inks and toners do not penetrate into the coatings. The durability of the printed image is significant, because the image must withstand various converting operations when the package is constructed. The most common method for obtaining good ink or toner adhesion is to oxidise the surface. Surface treatments are used to change the chemical composition, increase surface energy, modify surface morphology and topography, or remove contaminants and weak boundary layers. Two widely used methods are corona discharge treatment and flame treatment. These processes generally cause physical and chemical changes in a thin surface layer without affecting the bulk properties. Treatments will increase surface energy and also provide polar molecular groups necessary for good bonds between ink/toner and polymer molecules. In addition to printability, surface treatments also affect the sealing properties, i.e. initial heat sealing temperature, initial hot tack temperature, sealing window and seal strength of extrusion coatings. Both the sealability of packaging material and the tightness of the seal are critical points in the manufacturing process of packages and of the final package. The printability must be obtained without losing the sealability properties. In the first part of this research (TAPPI European PLACE 2007), surface energy, printability and sealability of low density polyethylene (PE-LD) coated paperboard after flame and corona treatments were studied. In this second part of the study, the research is extended to other polyolefins, i.e. high-density polyethylene (PE-HD) and polypropylene (PP). The surface chemistry is evaluated with contact angle measurements and X-ray photoelectron spectroscopy (XPS) measurements. Scanning electron microscopy (SEM) and optical profilometry are used to study the topographical and morphological changes on the surfaces. Furthermore, the heat sealing and hot tack properties, and water vapour barrier properties of the extrusion coatings are evaluated. The aim of this study is also to evaluate the printability of the extrusion coatings and to map out the role of surface modification in print quality formation. This study has concentrated on digital printing, particularly on the dry toner-based electrophotographic printing process. Flame treatment decreases the contact angle of water on PE-LD, PE-HD and PP coated papers more than corona treatment, but the lowest contact angle is obtained when the treatments are used simultaneously (i.e. co-effect of the treatments). Flame treatment deteriorates the sealability properties of PE-LD coated paper, whereas corona treatment improves sealability for example by decreasing the minimum heat sealing temperature. The sealability properties of PE-HD and PP coated papers are improved not only by corona treatment, but also by flame treatment. Flame treatment significantly improves the water vapour barrier of PEs. Where printability is concerned, it can be noticed that all the treatments improve rub-off resistance with PEs. With PE-LD flame is the most effective, and with PE-HD corona. With PP, the co-treatment gives the best result. Morphological changes in micro- and nano- scale were most observed on the flame treated PE-LD surface, whereas the electret phenomenon was observed on PE-LD, PE-HD and PP surfaces only after corona treatment.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Department of Materials Science, Paper Converting and Packaging Technology, Stora Enso
Contributors: Lahti, J., Tuominen, M., Penttinen, T., Räsänen, J. P., Kuusipalo, J.
Number of pages: 37
Pages: 278-314
Publication date: 2009

Host publication information

Title of host publication: TAPPI Press - 12th European PLACE Conference 2009
Volume: 1
ISBN (Print): 9781615679850
ASJC Scopus subject areas: Media Technology, Chemical Engineering(all), Chemistry(all), Mechanical Engineering, Materials Science(all)
Source: Scopus
Source ID: 77952354412

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

Novel equipment to simulate hot air heat sealability of packaging materials

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Materials Science, Research group: Paper Converting and Packaging
Contributors: Lahti, J., Kuusipalo, J., Auvinen, S.
Number of pages: 12
Pages: 237-248
Publication date: 1 Jan 2017

Host publication information

Title of host publication: 16th TAPPI European PLACE Conference 2017
Publisher: TAPPI Press
ISBN (Electronic): 9781510850880
ASJC Scopus subject areas: Media Technology, Chemical Engineering(all), Chemistry(all), Mechanical Engineering, Materials Science(all)
Source: Scopus
Source ID: 85044468996

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

Novel bio-based materials for active and intelligent packaging

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Materials Science
Contributors: Lahti, J., Kamppuri, T., Kuusipalo, J.
Number of pages: 1
Publication date: 1 Jan 2017

Host publication information

Title of host publication: 16th TAPPI European PLACE Conference 2017
Publisher: TAPPI Press
ISBN (Electronic): 9781510850880
ASJC Scopus subject areas: Media Technology, Chemical Engineering(all), Chemistry(all), Mechanical Engineering, Materials Science(all)
Source: Scopus
Source ID: 85044445672

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

Nanocellulose and Polylactic Acid Based Multilayer Coatings for Barrier Applications

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Materials Science and Environmental Engineering, Research group: Paper Converting and Packaging
Contributors: Lahti, J.
Number of pages: 10
Pages: 446-455
Publication date: 2019

Host publication information

Title of host publication: 17th Biennial TAPPI European PLACE Conference 2019
Publisher: TAPPI Press
ISBN (Electronic): 9781510888012
ASJC Scopus subject areas: Chemical Engineering(all), Chemistry(all), Mechanical Engineering, Media Technology, Materials Science(all)
Source: Scopus
Source ID: 85073782128

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

Market implementation of active and intelligent packaging-opportunities from a socio-economic perspective

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Materials Science and Environmental Engineering, Research group: Paper Converting and Packaging
Contributors: Lahti, J.
Number of pages: 9
Pages: 419-427
Publication date: 2019

Host publication information

Title of host publication: 17th Biennial TAPPI European PLACE Conference 2019
Publisher: TAPPI Press
ISBN (Electronic): 9781510888012
ASJC Scopus subject areas: Chemical Engineering(all), Chemistry(all), Mechanical Engineering, Media Technology, Materials Science(all)
Source: Scopus
Source ID: 85073779128

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

Statistical modeling of water vapor transmission rates for extrusion-coated papers

The testing of water vapor transmission rates (WVTR) for extrusion-coated papers can be a time-consuming task for laboratories. This study introduces a prediction model that provides an effective and helpful option to laboratory measurements. In practice, the WVTR of an extrusion-coated paper is affected by three main factors: coating weight (or squared mass) of the polymer concerned, the temperature and moisture content of the immediate surroundings. The prediction model determines mathematical connections between the WVTR and these variables covering the detected region of experimental WVTR results with a continuous estimation. By using mixing ratio as a variable of humidity, the model was found to provide accurate estimation across the field of experiments. As a result of this study, a practical computer program, which predicts the WVTR of a multilayer extrusion-coated paper as a function of user-defined temperature and relative humidity values and the layer structure of the coating, was developed. APPLICATION STATEMENT: This work shows how WVTR of a multilayer extrusion-coated paper can be estimated with the help of a statistical prediction model.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Department of Energy and Process Engineering, Department of Materials Science
Contributors: Lahtinen, K., Kuusipalo, J.
Publication date: 2008

Host publication information

Title of host publication: TAPPI 2008 PLACE Conference: Innovations in Flexible Consumer Packaging
ASJC Scopus subject areas: Chemical Engineering(all), Chemistry(all), Mechanical Engineering, Media Technology, Materials Science(all)
Source: Scopus
Source ID: 77950684840

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

Improving the effect of a nanoscale barrier coating on BOPP film properties by surface pretreatments

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Department of Materials Science, Engineering materials science and solutions (EMASS), Lappeenranta University of Technology, Paper Converting and Packaging Technology
Contributors: Lahtinen, K., Lahti, J., Johansson, P., Seppänen, T., Cameron, D. C.
Number of pages: 25
Pages: 469-493
Publication date: 2013

Host publication information

Title of host publication: 14th European PLACE Conference 2013
Volume: 1
Publisher: TAPPI Press
ISBN (Electronic): 9781510815568
ASJC Scopus subject areas: Media Technology, Chemical Engineering(all), Chemistry(all), Mechanical Engineering, Materials Science(all)
Source: Scopus
Source ID: 84962833172

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

Bilateral teleoperation of a hydraulic robotic manipulator in contact with physical and virtual constraints

Teleoperated robotic manipulators can be used to remotely operate within hazardous, hard to reach or dangerous environments. In tasks requiring handling of heavy objects with high forces, hydraulic manipulators have remained the most practical solution. Contrary to the previous research on teleoperation of hydraulic manipulators based on linearization and linear control theory, the present study proposes a full-dynamics-based bilateral force-reflected teleoperation, designed between a multiple degrees-of-freedom (n-DOF) electrical master manipulator and an n-DOF hydraulic slave manipulator. The used teleoperation method allows arbitrary motion and force scaling between the n-DOF manipulators, effectively enabling the use of two greatly dissimilar manipulators. The proposed teleoperation system is demonstrated with a full-scale two-DOF hydraulic slave manipulator (having 475 kg payload attached to the tip) in a free-space motion task, and in a constrained motion task including both real and virtual constraints in the environment. Despite the inherent highly nonlinear dynamic behaviour of hydraulic systems and challenges in realizing a bilateral teleoperation, the experimental results demonstrate that the proposed controller for fulldynamics- based teleoperation 1) can rigorously address the system nonlinearities, 2) can realize a high-performance bilateral teleoperation with hydraulic slave manipulators, and 3) is capable to operate in constrained motion with the environment having both real and virtual (i.e., artificially rendered) constraints.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Automation and Hydraulic Engineering, Research group: Innovative Hydraulic Automation
Contributors: Lampinen, S., Koivumäki, J., Mattila, J.
Publication date: 2018

Host publication information

Title of host publication: BATH/ASME 2018 Symposium on Fluid Power and Motion Control, FPMC 2018
Publisher: ASME
ISBN (Electronic): 9780791851968
ASJC Scopus subject areas: Fluid Flow and Transfer Processes, Control and Systems Engineering
Source: Scopus
Source ID: 85058006160

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

A new method to optimize natural convection heat sinks

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

General information

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

Publication information

Journal: Heat and Mass Transfer/Waerme- und Stoffuebertragung
Volume: 54
Issue number: 8
ISSN (Print): 0947-7411
Ratings: 
  • Scopus rating (2018): CiteScore 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

The electrical conductivity of human cerebrospinal fluid in vivo

Cerebrospinal fluid (CSF) is a clear, highly conductive liquid. Due to its much higher electric conductivity compared to other intracranial tissues, its influence is significant, for example, on volume conductor models, current distribution and heat generation in RF surgery. It has already been shown previously that it is important to include CSF in models to achieve more accurate results. Conductivity values measured in vitro are commonly used in modelling because in vivo values are not available. We have developed a method for taking calibrated in vivo human CSF conductivity measurements with a needle electrode. We used this method to take CSF conductivity measurements from four patients during brain surgeries that were conducted to remove tumours. The patients were selected so that the surgical path went through a ventricle to make sure that there was enough CSF volume to take the measurements. Two of the patients had meningiomas and the other two had gliomas. Measurements taken from clear CSF with our method resulted in conductivity values of 1.79–1.81 S/m. Impurities such as blood or the presence of cystic brain tumour decreased the measured electrical conductivity of CSF. Our results support the findings that the previously suggested conductivity value of 1.79 S/m for human CSF at 37 °C taken from in vitro measurements is applicable for modelling purposes.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Research group: Quantitative medical imaging, Faculty of Biomedical Sciences and Engineering
Contributors: Latikka, J., Eskola, H.
Number of pages: 4
Pages: 773-776
Publication date: 2019

Host publication information

Title of host publication: World Congress on Medical Physics and Biomedical Engineering 2018
Publisher: Springer
ISBN (Electronic): 978-981-10-9035-6

Publication series

Name: IFMBE Proceedings
Volume: 68
No.: 1
ISSN (Print): 1680-0737
ASJC Scopus subject areas: Bioengineering, Biomedical Engineering
Keywords: Brain tissue, Electrical properties, Measurements, Modelling

Bibliographical note

INT=tut-bmt,"Latikka, Juha"
jufoid=58152

Source: Scopus
Source ID: 85048302965

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

Effect of non-rubber components of NR on the carbon nanotube (CNT) localization in SBR/NR blends

Carbon nanotubes (CNTs) are mixed into SBR/NR and SBR/IR blends using a wet mixing process. The phase specific localization of CNTs in rubber blends is predicted theoretically using surface energy data of blend components and determined experimentally by means of the wetting concept. Almost all CNTs are found to be localized in the SBR matrix of SBR/IR blends due to the better affinity of CNTs to SBR than to IR. In contrast, a high CNT loading localized in the NR phase of SBR/NR blends results from the presence of phospholipids in NR. Electrical and mechanical properties of the rubber blends depend strongly on CNT localization. A lower CNT loading in SBR matrix of SBR/NR blends imparts a better wet grip and lower rolling resistance to tire tread compounds.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Engineering materials science and solutions (EMASS), Martin-Luther-University Halle-Wittenberg, Styron Deutschland GmbH, Fraunhofer IWM, Leibniz-Institut für Polymerforschung Dresden E.V., Dau Mot University, Tribhuvan University, Vodafone Department of Mobile Communications Systems
Contributors: Le, H. H., Parsekar, M., Ilisch, S., Henning, S., Das, A., Stöckelhuber, K. W., Beiner, M., Ho, C. A., Adhikari, R., Wießner, S., Heinrich, G., Radusch, H. J.
Number of pages: 14
Pages: 569-582
Publication date: 2014
Peer-reviewed: Yes

Publication information

Journal: Macromolecular Materials and Engineering
Volume: 299
Issue number: 5
ISSN (Print): 1438-7492
Ratings: 
  • Scopus rating (2014): CiteScore 4.7 SJR 1.009 SNIP 1.294
Original language: English
ASJC Scopus subject areas: Organic Chemistry, Materials Chemistry, Polymers and Plastics, Chemical Engineering(all)
Keywords: carbon nanotubes, filler localization, nanocomposites, rubber blends