FCC-hh: The Hadron Collider: Future Circular Collider Conceptual Design Report Volume 3

In response to the 2013 Update of the European Strategy for Particle Physics (EPPSU), the Future Circular Collider (FCC) study was launched as a world-wide international collaboration hosted by CERN. The FCC study covered an energy-frontier hadron collider (FCC-hh), a highest-luminosity high-energy lepton collider (FCC-ee), the corresponding 100 km tunnel infrastructure, as well as the physics opportunities of these two colliders, and a high-energy LHC, based on FCC-hh technology. This document constitutes the third volume of the FCC Conceptual Design Report, devoted to the hadron collider FCC-hh. It summarizes the FCC-hh physics discovery opportunities, presents the FCC-hh accelerator design, performance reach, and staged operation plan, discusses the underlying technologies, the civil engineering and technical infrastructure, and also sketches a possible implementation. Combining ingredients from the Large Hadron Collider (LHC), the high-luminosity LHC upgrade and adding novel technologies and approaches, the FCC-hh design aims at significantly extending the energy frontier to 100 TeV. Its unprecedented centre of-mass collision energy will make the FCC-hh a unique instrument to explore physics beyond the Standard Model, offering great direct sensitivity to new physics and discoveries.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research area: Design, Development and LCM, Automation Technology and Mechanical Engineering, Electrical Engineering, CNRS Centre National de la Recherche Scientifique, Istituto Nazionale di Fisica Nucleare Sezione di Bari (INFN BA), Universita degli Studi di Bari, Shahid Beheshti University, Bochvar Institute of Inorganic Materials (VNIINM), University of Oxford, Royal Holloway University (RHUL), University of Applied Sciences Technikum Wien (UAS TW), TOBB University of Economics and Technology, University of Belgrade, Harvard University, Universidad de Granada, Universitat Politecnica de Valencia, Spain, Paul Scherrer Institut, European Organization for Nuclear Research, Laboratorio Accelatori e Superconduttività Applicata, University Tor Vergata, Kahramanmaras Sutcu Imam University (KSU), Istituto Nazionale di Fisica Nucleare, Sezione di Catania, Università degli Studi di Catania, University of Manchester, French Atomic Energy Commission (CEA) Saclay, Fermi National Accelerator Laboratory, Istituto Nazionale di Fisica Nucleare, Sezione di Milano, University of Cambridge, University of Birmingham, Eskişehir Technical University (ESTU), Istanbul University, University of California Santa Cruz (UCSC), Linde Kryotechnik AG (Linde), Istituto Nazionale di Fisica Nucleare, Sezione di Firenze, CNR-INO, Università degli Studi di Milano, Massachusetts Institute of Technology, MAN Energy Solutions Schweiz AG (MAN ES), University of Münster, Laboratori Nazionali di Frascati (INFN LNF), Sezione di Padova (INFN PD), Universita degli Studi di Padova, Italy, Università di Insubria (UNINSUBRIA)
Contributors: Abada, A., Abbrescia, M., AbdusSalam, S. S., Abdyukhanov, I., Abelleira Fernandez, J., Abramov, A., Aburaia, M., Acar, A. O., Adzic, P. R., Agrawal, P., Aguilar-Saavedra, J. A., Aguilera-Verdugo, J. J., Aiba, M., Aichinger, I., Aielli, G., Akay, A., Akhundov, A., Aksakal, H., Albacete, J. L., Albergo, S., Alekou, A., Aleksa, M., Aleksan, R., Alemany Fernandez, R. M., Alexahin, Y., Alía, R. G., Alioli, S., Alipour Tehrani, N., Allanach, B. C., Allport, P. P., Altınlı, M., Altmannshofer, W., Ambrosio, G., Amorim, D., Amstutz, O., Anderlini, L., Andreazza, A., Andreini, M., Andriatis, A., Andris, C., Andronic, A., Angelucci, M., Antinori, F., Antipov, S. A., Antonelli, M., Antonello, M., Lehtinen, T., Penttinen, J. P., Salmi, T., Stenvall, A.
Number of pages: 353
Pages: 755-1107
Publication date: 1 Jul 2019
Peer-reviewed: Yes

Publication information

Journal: European Physical Journal: Special Topics
Volume: 228
Issue number: 4
ISSN (Print): 1951-6355
Original language: English
ASJC Scopus subject areas: Materials Science(all), Physics and Astronomy(all), Physical and Theoretical Chemistry
Source: Scopus
Source ID: 85068232451

Research output: Contribution to journalArticleScientificpeer-review

Frequency Comb Generation in a Continuous-Wave Pumped Second-Order Nonlinear Waveguide Resonator

Optical frequency comb generation has been experimentally studied using an integrated system based on a lithium niobate waveguide resonator featuring a strong quadratic nonlinearity. Our theoretical model shows good agreement with the experimental results.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Physics, Paderborn University, University of Helsinki, VTT Technical Research Centre of Finland
Contributors: Abdallah, Z., Stefszky, M., Ulvila, V., Silberhorn, C., Vainio, M.
Publication date: 1 May 2019

Host publication information

Title of host publication: 2019 Conference on Lasers and Electro-Optics, CLEO 2019 - Proceedings
Publisher: IEEE
ISBN (Electronic): 9781943580576
ASJC Scopus subject areas: Spectroscopy, Industrial and Manufacturing Engineering, Safety, Risk, Reliability and Quality, Management, Monitoring, Policy and Law, Electronic, Optical and Magnetic Materials, Radiology Nuclear Medicine and imaging, Instrumentation, Atomic and Molecular Physics, and Optics
Source: Scopus
Source ID: 85069196416

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

Synthesis and Photophysical Properties of Two Diazaporphyrin-Porphyrin Hetero Dimers in Polar and Nonpolar Solutions

Two diazaporphyrin (DAP)-porphyrin hetero dimers, in β-meso and β-β configurations, were prepared to study their photoinduced intramolecular electron transfer properties. The two meso nitrogen atoms in the porphyrin ring of DAP change its redox potential, making DAP more easily reduced, compared to its porphyrin counterpart. A charge-transfer from porphyrin to DAP in both hetero dimers was verified by versatile optical spectroscopic methods. The steady-state fluorescence spectra indicated an efficient intramolecular exciplex formation for both dimers. For the β-meso dimer, ultrafast time-resolved spectroscopic methods revealed the subpicosecond formation of two types of primary short-living (1-18 ps) intramolecular exciplexes, which relaxed in toluene to form a long-living final exciplex (1.4 ns) followed by a longer-living charge transfer complex (>5 ns). However, in benzonitrile, the lifetime of the final exciplex was longer (660 ps) as was that of the charge transfer complex (180 ps). The β-β analogue formed similar short-living exciplexes in both solvents, but the final exciplex and the charge transfer state had significantly shorter lifetimes. The electrochemical redox potential measurements and density functional theory calculations supported the proposed mechanism.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Research group: Supramolecular photochemistry, Frontier Photonics, Tampere Graduate School in Information Science and Engineering (TISE), Kyoto Women's University, Department of Molecular Engineering, Graduate School of Engineering, Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyushu University, Niigata University
Contributors: Abou-Chahine, F., Fujii, D., Imahori, H., Nakano, H., Tkachenko, N. V., Matano, Y., Lemmetyinen, H.
Number of pages: 10
Pages: 7328-7337
Publication date: 18 Jun 2015
Peer-reviewed: Yes
Early online date: 30 Jan 2015

Publication information

Journal: Journal of Physical Chemistry Part B
Volume: 119
Issue number: 24
ISSN (Print): 1520-6106
Ratings: 
  • Scopus rating (2015): CiteScore 3.25 SJR 1.335 SNIP 1.058
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Materials Chemistry, Surfaces, Coatings and Films
Source: Scopus
Source ID: 84934905262

Research output: Contribution to journalArticleScientificpeer-review

Synthesis and study of electrochemical and optical properties of substituted perylenemonoimides in solutions and on solid surfaces

A new and efficient methodology towards the synthesis of 7-pyrrolidinyl and 7,12-bispyrrolidinyl perylenemonoimide monoanhydrides (PMI monoanhydrides) and their corresponding dicarboxylic acids is devised. The high yields (70-96%) and facile synthesis of PMI monoanhydrides, as compared to traditional methodologies, make the method attractive and versatile. The reported 7,12-bispyrrolidinyl PMI monoanhydrides are a new family of peryleneimides, where both the bay-substituents are located towards the anhydride cycle. The electrochemical and optical properties of target molecules and their precursors were investigated using UV-Vis spectroscopy and differential pulse voltammetry. Atomic charges and electronic properties were calculated using density functional theory (DFT). In addition, self-assembling monolayers of the PMI monoanhydrides and their corresponding diacids were successfully formed over ZnO and TiO<inf>2</inf> films. The results of the current study indicate that these molecules are potentially good candidates for various applications in the fields of organic electronics and solar cells.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Research group: Supramolecular photochemistry, Frontier Photonics
Contributors: Ahmed, Z., George, L., Hiltunen, A., Lemmetyinen, H., Hukka, T., Efimov, A.
Number of pages: 8
Pages: 13332-13339
Publication date: 7 Jul 2015
Peer-reviewed: Yes

Publication information

Journal: Journal of Materials Chemistry A
Volume: 3
Issue number: 25
ISSN (Print): 2050-7488
Ratings: 
  • Scopus rating (2015): CiteScore 8.36 SJR 2.62 SNIP 1.63
Original language: English
ASJC Scopus subject areas: Chemistry(all), Renewable Energy, Sustainability and the Environment, Materials Science(all)
Source: Scopus
Source ID: 84934958229

Research output: Contribution to journalArticleScientificpeer-review

Magnetic origin of the chemical balance in alloyed Fe-Cr stainless steels: First-principles and Ising model study

Iron-chromium is the base material for most of the stainless steel grades. Recently, new insights into the origins of fundamental physical and chemical characteristics of Fe-Cr based alloys have been achieved. Some of the new results are quite unexpected and call for further investigations. The present study focuses on the magnetic contribution in the atomic driving forces related to the chemical composition in Fe-Cr when alloyed with Al, Ti, V, Mn, Co, Ni, and Mo. Using the ab initio exact muffin-tin orbitals method combined with an Ising-type spin model, we demonstrate that the magnetic moment of the solute atoms with the induced changes in the magnetic moments of the host atoms form the main factor in determining the mixing energy and chemical potentials of low-Cr Fe-Cr based alloys. The results obtained in the present work are related to the designing and tuning of the microstructure and corrosion protection of low-Cr steels.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Computational Science X (CompX), Turun Yliopisto/Turun Biomateriaalikeskus, Department of Physics and Astronomy, University of Turku, Abo Akad Univ, Abo Akademi University, Dept Phys, Uppsala University, Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences
Contributors: Airiskallio, E., Nurmi, E., Väyrynen, I. J., Kokko, K., Ropo, M., Punkkinen, M. P. J., Johansson, B., Vitos, L.
Number of pages: 6
Pages: 135-140
Publication date: 2014
Peer-reviewed: Yes

Publication information

Journal: Computational Materials Science
Volume: 92
ISSN (Print): 0927-0256
Ratings: 
  • Scopus rating (2014): CiteScore 2.47 SJR 1.098 SNIP 1.612
Original language: English
ASJC Scopus subject areas: Computer Science(all), Chemistry(all), Materials Science(all), Mechanics of Materials, Physics and Astronomy(all), Computational Mathematics
Keywords: Al, Chemical potential, Co, Corrosion protection, Cr, Fe, First principles calculation, Ising model, Magnetic moment, Mixing energy, Mn, Mo, Ni, Stainless steel, Ti, V
Source: Scopus
Source ID: 84902660256

Research output: Contribution to journalArticleScientificpeer-review

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

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

General information

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

Publication information

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

Research output: Contribution to journalArticleScientificpeer-review

Photoresponsive liquid-crystalline polymer films bilayered with an inverse opal structure

An inverse opal film was layered to a photodeformable film, and its photoresponsive behavior was investigated. This bilayer films composed of colorless photonic crystal using inverse opal structures and colored photoresponsive layers with azobenzene-containing CLCP.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Research group: Supramolecular photochemistry, Tokyo Institute of Technology, Japan Science and Technology Agency
Contributors: Akamatsu, N., Aizawa, M., Tatsumi, R., Hisano, K., Priimägi, A., Shishido, A.
Number of pages: 4
Pages: 145-148
Publication date: 2016
Peer-reviewed: Yes

Publication information

Journal: JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY
Volume: 29
Issue number: 1
ISSN (Print): 0914-9244
Ratings: 
  • Scopus rating (2016): CiteScore 0.88 SJR 0.3 SNIP 0.558
Original language: English
ASJC Scopus subject areas: Organic Chemistry, Polymers and Plastics, Materials Chemistry
Keywords: Bragg diffraction, Inverse opal structure, Photoresponsive film
Source: Scopus
Source ID: 84981200985

Research output: Contribution to journalArticleScientificpeer-review

Novel derivatives of bacteriochlorophyll a: Complex formation with albumin and the mechanism of tumor cell photodamage

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Frontier Photonics, Emanuel’ Institute of Biochemical Physics, Russian Academy of Sciences, M.V. Lomonosov Moscow State University of Fine Chemical Technologies, Georgian Technical University, St. Petersburg State Polytechnical University, N.N. Blokhin Russian Cancer Research Center, Russian Academy of Medical Sciences
Contributors: Akimova, A. V., Grin, M. A., Golovina, G. V., Kokrashvili, T. A., Vinogradov, A. M., Mironov, A. F., Rychkov, G. N., Shtil, A. A., Kuzmin, V. A., Durandin, N. A.
Number of pages: 4
Pages: 17-20
Publication date: 2014
Peer-reviewed: Yes

Publication information

Journal: DOKLADY BIOCHEMISTRY AND BIOPHYSICS
Volume: 454
Issue number: 1
ISSN (Print): 1607-6729
Ratings: 
  • Scopus rating (2014): CiteScore 0.38 SJR 0.208 SNIP 0.312
Original language: English
ASJC Scopus subject areas: Biophysics, Chemistry(all), Medicine(all), Biochemistry
Source: Scopus
Source ID: 84896349301

Research output: Contribution to journalArticleScientificpeer-review

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

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

General information

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

Publication information

Journal: Fuel
Volume: 162
ISSN (Print): 0016-2361
Ratings: 
  • Scopus rating (2015): CiteScore 4.46 SJR 1.781 SNIP 2.091
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

Methods for simultaneous robot-world-hand–eye calibration: A comparative study

In this paper, we propose two novel methods for robot-world-hand-eye calibration and provide a comparative analysis against six state-of-the-art methods. We examine the calibration problem from two alternative geometrical interpretations, called 'hand-eye' and 'robot-world-hand-eye', respectively. The study analyses the effects of specifying the objective function as pose error or reprojection error minimization problem. We provide three real and three simulated datasets with rendered images as part of the study. In addition, we propose a robotic arm error modeling approach to be used along with the simulated datasets for generating a realistic response. The tests on simulated data are performed in both ideal cases and with pseudo-realistic robotic arm pose and visual noise. Our methods show significant improvement and robustness on many metrics in various scenarios compared to state-of-the-art methods.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Computing Sciences, Remote Handling Project Team
Contributors: Ali, I., Suominen, O., Gotchev, A., Morales, E. R.
Publication date: 2 Jun 2019
Peer-reviewed: Yes

Publication information

Journal: Sensors (Switzerland)
Volume: 19
Issue number: 12
Article number: 2837
ISSN (Print): 1424-8220
Original language: English
ASJC Scopus subject areas: Analytical Chemistry, Atomic and Molecular Physics, and Optics, Biochemistry, Instrumentation, Electrical and Electronic Engineering
Keywords: Hand-eye calibration, Optimization, Robot-world-hand-eye calibration
Electronic versions: 
Source: Scopus
Source ID: 85068904338

Research output: Contribution to journalArticleScientificpeer-review

Ambient-Pressure XPS Study of a Ni-Fe Electrocatalyst for the Oxygen Evolution Reaction

Chemical analysis of solid-liquid interfaces under electrochemical conditions has recently become feasible due to the development of new synchrotron radiation techniques. Here we report the use of "tender" X-ray ambient-pressure X-ray photoelectron spectroscopy (APXPS) to characterize a thin film of Ni-Fe oxyhydroxide electrodeposited on Au as the working electrode at different applied potentials in 0.1 M KOH as the electrolyte. Our results show that the as-prepared 7 nm thick Ni-Fe (50% Fe) film contains Fe and Ni in both their metallic as well as oxidized states, and undergoes further oxidation when the sample is subjected to electrochemical oxidation-reduction cycles. Metallic Fe is oxidized to Fe3+ and metallic Ni to Ni2+/3+. This work shows that it is possible to monitor the chemical nature of the Ni-Fe catalyst as a function of potential when the corresponding current densities are small. This allows for operando measurements just above the onset of OER; however, current densities as they are desired in photoelectrochemical devices (∼1-10 mA cm-2) could not be achieved in this work, due to ohmic losses in the thin electrolyte film. We use a two-dimensional model to describe the spatial distribution of the electrochemical potential, current density, and pH as a function of the position above the electrolyte meniscus, to provide guidance toward enabling the acquisition of operando APXPS at high current density. The shifts in binding energy of water with applied potential predicted by the model are in good agreement with the experimental values.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Optoelectronics Research Centre, Research group: Surface Science, SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, Department of Chemical and Biomolecular Engineering, Berkeley, Materials Sciences Division, Lawrence Berkeley National Laboratory, Materials and Corrosion Engineering, Exponent, Inc., Polymer Science and Materials Chemistry
Contributors: Ali-Löytty, H., Louie, M. W., Singh, M. R., Li, L., Sanchez Casalongue, H. G., Ogasawara, H., Crumlin, E. J., Liu, Z., Bell, A. T., Nilsson, A., Friebel, D.
Number of pages: 7
Pages: 2247-2253
Publication date: 4 Feb 2016
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry C
Volume: 120
Issue number: 4
ISSN (Print): 1932-7447
Ratings: 
  • Scopus rating (2016): CiteScore 4.48 SJR 1.964 SNIP 1.189
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Electronic, Optical and Magnetic Materials, Surfaces, Coatings and Films, Energy(all)
Electronic versions: 
URLs: 
Source: Scopus
Source ID: 84957588014

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 5.19 SJR 1.891 SNIP 2.459
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

Guanidinium Pairing Facilitates Membrane Translocation

Ab initio free energy calculations of guanidinium pairing in aqueous solution confirm the counterintuitive conjecture that the like-charge ion pair is thermodynamically stable. Transferring the guanidinium pair to the inside of a POPC lipid bilayer, like-charge ion pairing is found to occur also inside the membrane defect. It is found to contribute to the nonadditivity of ion transfer, thereby facilitating the presence of ions inside the bilayer. The effect is quantified by free energy decomposition and comparison with ammonium ions, which do not form a stable pair. The presence of two charges inside the center of the bilayer leads to the formation of a pore. Potential consequences for cell penetrating peptides and ion conduction are drawn.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Physics, Universität Regensburg, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Bijenička Cesta 54
Contributors: Allolio, C., Baxova, K., Vazdar, M., Jungwirth, P.
Number of pages: 11
Pages: 143-153
Publication date: 14 Jan 2016
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry Part B
Volume: 120
Issue number: 1
ISSN (Print): 1520-6106
Ratings: 
  • Scopus rating (2016): CiteScore 3.03 SJR 1.345 SNIP 1.023
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Materials Chemistry, Surfaces, Coatings and Films

Bibliographical note

EXT="Vazdar, Mario"

Source: Scopus
Source ID: 84955271467

Research output: Contribution to journalArticleScientificpeer-review

Impact of selective catalytic reduction on exhaust particle formation over excess ammonia events

The introduction of selective catalytic reduction (SCR) aftertreatment to meet stringent diesel NOx emission standards around the world increases exhaust ammonia. Further to the direct air quality and health implications of ammonia, this may also lead to particle formation in the exhaust. In this study, an ammonia SCR system was examined with respect to its impact on both solid and total exhaust particle number and size distribution, downstream of a diesel particulate filter (DPF). Fuel post-injection was conducted in some tests to investigate the effect of ammonia during active DPF regeneration. On average, the post-DPF solid >23 nm and total x control. Ammonia did not have a significant additional effect on the high particle concentrations measured during DPF regeneration. Based on species availability and formation conditions, sulfate, nitrate, and chloride salts with ammonium are possible sources of the new particles formed. Ammonia-induced particle formation corresponds to an environmental problem which is not adequately addressed by current regulations.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Urban circular bioeconomy (UrCirBio), Laboratory of Applied Thermodynamics, Aristotle University of Thessaloniki, European Commission-JRC, AVL List GmbH
Contributors: Amanatidis, S., Ntziachristos, L., Giechaskiel, B., Bergmann, A., Samaras, Z.
Number of pages: 8
Pages: 11527-11534
Publication date: 7 Oct 2014
Peer-reviewed: Yes

Publication information

Journal: Environmental Science and Technology
Volume: 48
Issue number: 19
ISSN (Print): 0013-936X
Ratings: 
  • Scopus rating (2014): CiteScore 5.5 SJR 2.777 SNIP 1.992
Original language: English
ASJC Scopus subject areas: Chemistry(all), Environmental Chemistry
Source: Scopus
Source ID: 84907936083

Research output: Contribution to journalArticleScientificpeer-review

Possible strategy to use differential mobility spectrometry in real time applications

Differential Mobility Spectrometry (DMS), also called as FAIMS is a variation of atmospheric pressure ion mobility measurement techniques and is capable of providing information about the electric field - mobility dependence of ions. In this method, a combined electric field is used. This field consists of asymmetric oscillating electric field of high intensity and low static field component. Analytical information in DMS is 2-dimensional dependence of ionic current on oscillating field amplitude and the value of static field intensity. The measurement of DMS signal for whole ranges of both variables is time consuming and also generates lot of data. It is a disadvantage of DMS method, which limits the use of this otherwise powerful technology in real time applications that require a response time of few seconds. This paper presents a way to limit measurement time by heuristic knowledge of the properties of the data space and another method based on the concept of Shannon Entropy to find operating parameters satisfying both separation and signal to noise ratio requirements.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: BioMediTech, Tampere University Hospital, Military University of Technology, Department of Surgery, Tampere University of Applied Sciences, LappeenrantaLahti University of Technology LUT
Contributors: Anttalainen, O., Puton, J., Kontunen, A., Karjalainen, M., Kumpulainen, P., Oksala, N., Safaei, Z., Roine, A.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: International Journal for Ion Mobility Spectrometry
ISSN (Print): 1435-6163
Original language: English
ASJC Scopus subject areas: Spectroscopy
Keywords: Differential mobility spectrometry, DMS, FAIMS, Shannon entropy
Source: Scopus
Source ID: 85067989586

Research output: Contribution to journalArticleScientificpeer-review

Hydrolysis and drug release from poly(ethylene glycol)-modified lactone polymers with open porosity

The ability to release active agents from a porous scaffold structure in situ enables the simultaneous structural support for the cells proliferating and differentiating towards tissue as well as the stimulation of tissue regeneration. Due to the great potentiality of such approach, drug-releasing scaffolds were fabricated from hydrolytically degradable polymers. Three copolymers of poly(ethylene glycol), ɛ-caprolactone, L- and D,L-lactide were synthesized and blended with bone-growth inducing active agents, dexamethasone (DM) and 2-phospho-L-ascorbic acid trisodium salt (AS). Porous scaffolds were prepared by means of super-critical carbon dioxide foaming. In the final scaffold structures, the particle size, location and the water solubility of the drug affected the release kinetics. As the large and water soluble AS particles were more exposed to the buffer solution compared to small DM particles, the AS release was burst-like whereas DM showed a long-term release. The material structure had a significant effect on the release kinetics as the porous scaffolds released active agents faster compared to the solid cylinders. Furthermore, this study showed the strong effect of polymer degradation and wettability on the release, which were more determinative than the pore architecture.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: BioMediTech, Aalto University, Orton Orthopaedic Hospital
Contributors: Asikainen, S., Paakinaho, K., Kyhkynen, A. K., Hannula, M., Malin, M., Ahola, N., Kellomäki, M., Seppälä, J.
Number of pages: 11
Pages: 165-175
Publication date: 1 Apr 2019
Peer-reviewed: Yes

Publication information

Journal: European Polymer Journal
Volume: 113
ISSN (Print): 0014-3057
Original language: English
ASJC Scopus subject areas: Physics and Astronomy(all), Organic Chemistry, Polymers and Plastics, Materials Chemistry
Keywords: 2-Phospho-L-ascorbic acid trisodium salt, Bulk degradation, Dexamethasone, Drug release, Hydrolytic degradation, Supercritical carbon dioxide foaming
Source: Scopus
Source ID: 85060767586

Research output: Contribution to journalArticleScientificpeer-review

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

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

General information

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

Publication information

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

Bibliographical note

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

Source: Scopus
Source ID: 85068362408

Research output: Contribution to journalArticleScientificpeer-review

Detection of DNA hybridisation in a diluted serum matrix by surface plasmon resonance and film bulk acoustic resonators

Nanomolar quantities of single-stranded DNA products ∼ 100 nucleotides long can be detected in diluted 1% serum by surface plasmon resonance (SPR) and film bulk acoustic resonators (FBARs). We have used a novel FBAR sensor in parallel with SPR and obtained promising results with both the acoustic and the optical device. Oligonucleotides and a repellent lipoamide, Lipa-DEA, were allowed to assemble on the sensor chip surfaces for only 15 min by dispensing. Lipa-DEA surrounds the analyte-binding probes on the surface and effectively reduces the non-specific binding of bovine serum albumin and non-complementary strands. In a highly diluted serum matrix, the non-specific binding is, however, a hindrance, and the background response must be reduced. Nanomolar concentrations of short complementary oligos could be detected in buffer, whereas the response was too low to be measured in serum. DNA strands that are approximately 100 base pairs long at concentrations as low as 1-nM could be detected both in buffer and in 1% serum by both SPR and the FBAR resonator.

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, HCI e 486.1, Siemens AG
Contributors: Auer, S., Nirschl, M., Schreiter, M., Vikholm-Lundin, I.
Number of pages: 10
Pages: 1387-1396
Publication date: May 2011
Peer-reviewed: Yes

Publication information

Journal: Analytical and Bioanalytical Chemistry
Volume: 400
Issue number: 5
ISSN (Print): 1618-2642
Ratings: 
  • Scopus rating (2011): CiteScore 3.47 SJR 1.37 SNIP 1.27
Original language: English
ASJC Scopus subject areas: Analytical Chemistry, Biochemistry
Keywords: DNA hybridisation detection, DNA sensor, Film bulk acoustic resonator, Self-assembled monolayer, Serum, Surface plasmon resonance
Source: Scopus
Source ID: 79955562374

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
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

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

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

General information

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

Publication information

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

Research output: Contribution to journalArticleScientificpeer-review

Photophysical properties of porphyrin dimer-single-walled carbon nanotube linked systems

Porphyrin dimers were covalently grafted onto electron-accepting single-walled carbon nanotube (SWNT) sidewalls by direct aryl radical addition reaction with an m-or p-phenylene linker with the help of p-p interaction between the porphyrins. A splitting of the porphyrin Soret band and DFT calculations supported the selective formation of the porphyrin dimers on the sidewall of SWNTs. Photoexcitation of the porphyrin dimers on the SWNT resulted in the formation of the exciplex state, which directly decayed to the ground state without yielding the complete charge-separated state. Lifetimes of the porphyrin dimer-SWNT exciplex were longer than that of a porphyrin monomer-SWNT exciplex due to the stabilization by p-electron interaction over two porphyrin rings. In addition, the weaker electronic coupling through the meta-linkage than the para-one may be responsible for the exciplex lifetime of the porphyrin dimer-SWNT with the m-phenylene linker (49 ps) longer than that with the p-phenylene one (24 ps). The results obtained here provide the basic information on the effect of the donor dimerization on the photodynamic behavior of the exciplex state in donor-acceptor linked systems. [Figure presented]

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Kyoto Women's University
Contributors: Baek, J., Umeyama, T., Mizuno, S., Tkachenko, N. V., Imahori, H.
Publication date: 2017
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry C
Volume: 121
Issue number: 39
ISSN (Print): 1932-7447
Ratings: 
  • Scopus rating (2017): CiteScore 4.58 SJR 2.135 SNIP 1.135
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Energy(all), Physical and Theoretical Chemistry, Surfaces, Coatings and Films
Source: Scopus
Source ID: 85032629899

Research output: Contribution to journalArticleScientificpeer-review

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

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

General information

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

Publication information

Journal: Fuel
Volume: 155
ISSN (Print): 0016-2361
Ratings: 
  • Scopus rating (2015): CiteScore 4.46 SJR 1.781 SNIP 2.091
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

Polarization resolved photoluminescence in GaAs1−xBix/GaAs quantum wells

We have investigated polarization resolved photoluminescence (PL) of GaAs1−xBix/GaAs quantum wells (QWs) with different Bi concentrations in the dilute range (x1−xBix/GaAs QWs increase with the increase of Bi concentration. Excitonic gex-factors of 4 and 10 were obtained at 15 T for as-grown GaAs1−xBix/GaAs QWs with 1.2% and 1.9% Bi concentration, respectively. These values evidence an important increase of electron and hole g-factors with the introduction of Bi in GaAs.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Optoelectronics Research Centre, Research group: Semiconductor Technology and Applications, Universid ade Federal de São Carlos, University of Nottingham, Universidade Federal de São Carlos
Contributors: Balanta, M. A. G., Orsi Gordo, V., Carvalho, A. R. H., Puustinen, J., Alghamdi, H. M., Henini, M., Galeti, H. V. A., Guina, M., Galvão Gobato, Y.
Number of pages: 4
Pages: 49-52
Publication date: Feb 2017
Peer-reviewed: Yes
Early online date: 13 Oct 2016

Publication information

Journal: Journal of Luminescence
Volume: 182
ISSN (Print): 0022-2313
Ratings: 
  • Scopus rating (2017): CiteScore 2.72 SJR 0.694 SNIP 1.075
Original language: English
ASJC Scopus subject areas: Biophysics, Chemistry(all), Atomic and Molecular Physics, and Optics, Biochemistry, Condensed Matter Physics
Source: Scopus
Source ID: 84992707527

Research output: Contribution to journalArticleScientificpeer-review

Water-Responsive and Mechanically Adaptive Natural Rubber Composites by in Situ Modification of Mineral Filler Structures

A new biomimetic stimuli-responsive adaptive elastomeric material, whose mechanical properties are altered by a water treatment is reported in this paper. This material is a calcium sulphate (CaSO4) filled composite with an epoxidized natural rubber (ENR) matrix. By exploiting various phase transformation processes that arise when CaSO4 is hydrated, several different crystal structures of CaSO4·xH2O can be developed in the cross-linked ENR matrix. Significant improvements in the mechanical and thermal properties are then observed in the water-treated composites. When compared with the untreated sample, there is approximately 100% increase in the dynamic modulus. The thermal stability of the composites is also improved by increasing the maximum degradation rate temperature by about 20 °C. This change in behavior results from an in situ development of hydrated crystal structures of the nanosized CaSO4 particles in the ENR matrix, which has been verified using Raman spectroscopy, transmission electron microscopy, atomic force microscopy, and X-ray scattering. This work provides a promising and relatively simple pathway for the development of next generation of mechanically adaptive elastomeric materials by an eco-friendly route, which may eventually also be developed into an innovative biodegradable and biocompatible smart polymeric material.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Leibniz-Institut für Polymerforschung Dresden E.V., University of Massachusetts Lowell, Vodafone Department of Mobile Communications Systems, Queen Mary University of London
Contributors: Banerjee, S. S., Hait, S., Natarajan, T. S., Wießner, S., Stöckelhuber, K. W., Jehnichen, D., Janke, A., Fischer, D., Heinrich, G., Busfield, J. J., Das, A.
Number of pages: 8
Pages: 5168-5175
Publication date: 20 Jun 2019
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry B
Volume: 123
Issue number: 24
ISSN (Print): 1520-6106
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Surfaces, Coatings and Films, Materials Chemistry
Source: Scopus
Source ID: 85067653290

Research output: Contribution to journalArticleScientificpeer-review

Temperature scanning stress relaxation behavior of water responsive and mechanically adaptive elastomer nanocomposites

The decrease of stress at constant strain, that is, the stress relaxation process as a function of temperature, is a central mechanical characteristics of elastomer nanocomposites for their potential applications. However, in the conventional stress relaxation test, the relaxation behavior is usually determined as a function of time at constant temperature. The present work reports the temperature scanning stress relaxation (TSSR) characteristics of a new kind of mechanically adaptive elastomer nanocomposite by monitoring the nonisothermal relaxation behavior as a function of temperature. This kind of adaptive elastomer nanocomposite was prepared by introducing calcium sulfate (CaSO4), as the water-responsive phase into the hydrophilic elastomer matrix. The influence of water-induced structural changes on TSSR behavior was investigated. Water treatment had a strong effect on the shape of the relaxation spectrum of the nanocomposite. It was revealed that the in situ development of hydrated nano-rod crystal structures of CaSO4 in the elastomer matrix was responsible for the changes in the mechanical relaxation behavior of the composites. Atomic force microscopy was used to verify this nano-rod crystal morphology in the elastomer matrix. The mechanism of water-induced mechanical reinforcement of the composite was explored from dynamic mechanical analysis of the material and correlated with its stress relaxation behavior.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Leibniz-Institut für Polymerforschung Dresden E.V., University of Massachusetts Lowell, Vodafone Department of Mobile Communications Systems
Contributors: Banerjee, S. S., Natarajan, T. S., Subramani B., E., Wießner, S., Janke, A., Heinrich, G., Das, A.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Journal of Applied Polymer Science
Article number: 48344
ISSN (Print): 0021-8995
Original language: English
ASJC Scopus subject areas: Chemistry(all), Surfaces, Coatings and Films, Polymers and Plastics, Materials Chemistry
Keywords: adaptive elastomer nanocomposite, calcium sulphate, mechanical reinforcement, morphology, temperature scanning stress relaxation
Source: Scopus
Source ID: 85070677934

Research output: Contribution to journalArticleScientificpeer-review

Compatibilization of natural rubber/nitrile rubber blends by sol–gel nano-silica generated by in situ method

Abstract: Controlled growth of in situ silica, into natural rubber (NR)/nitrile rubber (NBR) blend (40/60 composition by weight) following solution sol–gel method, results in a coherent blend morphology with enhanced composite properties. Similar composites, i.e., in situ silica-filled NR/NBR blend (40/60 by weight), showed better mechanical properties than any other composition that were prepared by soaking sol–gel method in earlier study. However, silica content in the rubber blend was limited to 20 phr (parts per hundred parts of rubber) and could not be increased under experimental condition following soaking sol–gel method. In the present work, silica content is increased (up to 30 phr) beyond that limit for the same blend composition. Accordingly, mechanical properties of the NR/NBR composites are improved. Use of a silane coupling agent, viz., bis-(3-triethoxysilylpropyl)-tetra sulfide, in the reactive sol–gel system during in situ silica generation brings in remarkable effect in silica distribution, rubber–filler interaction and mechanical properties of the composites. TEM micrographs of the selected composites reveal that silica is mostly grown at the interfacial region, when silane is used in particular. This results in further enhancement in mechanical properties and compatibility of the blend at the same silica content as evident from stress–strain and dynamic mechanical analysis studies. The reinforcement of effect in situ silica is assessed by Guth–Gold equation and modified form of Guth equation (with shape factor f = 2.53). The results are supported by the detailed studies on rheological, morphological, mechanical and viscoelastic properties of the composites. Graphical Abstract: [Figure not available: see fulltext.]

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Materials Science, Visvesvaraya National Institute of Technology, Indian Rubber Manufacturers Research Association, Department of Elastomers, Leibniz-Institut für Polymerforschung Dresden E.V., University of Kalyani
Contributors: Bansod, N. D., Kapgate, B. P., Das, C., Das, A., Basu, D., Debnath, S. C.
Number of pages: 12
Pages: 548–559
Publication date: 2016
Peer-reviewed: Yes

Publication information

Journal: JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
Volume: 80
Issue number: 2
ISSN (Print): 0928-0707
Ratings: 
  • Scopus rating (2016): CiteScore 1.53 SJR 0.48 SNIP 0.678
Original language: English
ASJC Scopus subject areas: Chemistry(all), Condensed Matter Physics, Biomaterials, Ceramics and Composites, Electronic, Optical and Magnetic Materials, Materials Chemistry
Keywords: In situ silica, Reinforcement, Rubber blend, Rubber–filler interaction, Silane treatment, Sol–gel method
Source: Scopus
Source ID: 84974817789

Research output: Contribution to journalArticleScientificpeer-review

Optical vortex generation in nematic liquid crystal light valves

A nematic liquid crystal light valve (LCLV) is made by using a photosensitive material as one of the cell-confining walls. The liquid crystals (LCs) are homeotropically aligned and with a negative anisotropy; therefore, they naturally produce topological defects when they reorient under the application of an electric field. In our work, we show that by sending circularly polarized light beams onto the photosensitive wall of the light valve, it is possible to locally induce the reorientation and to generate vortex-like defects that remain, each stable and trapped at the chosen location. We demonstrate the ability of the system to create optical vortices with opposite topological charge that, consistently with angular momentum conservation, both derive from the same defect created in the LC texture.The efficiency of the spin-to-orbital angular momentum conversion is measured as a function of the system control parameters, namely the low-frequency electric field applied to the light valve and the intensity of the optical beam inducing the matter defect.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Frontier Photonics, CNRS, NooEL (Nonlinear Optics and OptoElectronics Laboratory), University “Roma Tre”
Contributors: Barboza, R., Bortolozzo, U., Assanto, G., Residori, S.
Number of pages: 7
Pages: 24-30
Publication date: 1 Mar 2013
Peer-reviewed: Yes

Publication information

Journal: Molecular Crystals and Liquid Crystals
Volume: 572
Issue number: 1
ISSN (Print): 1542-1406
Ratings: 
  • Scopus rating (2013): CiteScore 0.52 SJR 0.279 SNIP 0.38
Original language: English
ASJC Scopus subject areas: Chemistry(all), Condensed Matter Physics, Materials Science(all)
Keywords: Liquid crystal light valves, optical vortices, spin-to-orbital angular momentum conversion, topological defects
Source: Scopus
Source ID: 84876183883

Research output: Contribution to journalArticleScientificpeer-review

Affine-response model of molecular solvation of ions: Accurate predictions of asymmetric charging free energies

Two mechanisms have been proposed to drive asymmetric solvent response to a solute charge: a static potential contribution similar to the liquid-vapor potential, and a steric contribution associated with a water molecules structure and charge distribution. In this work, we use free-energy perturbation molecular-dynamics calculations in explicit water to show that these mechanisms act in complementary regimes; the large static potential (∼44kJ/mol/e) dominates asymmetric response for deeply buried charges, and the steric contribution dominates for charges near the solute-solvent interface. Therefore, both mechanisms must be included in order to fully account for asymmetric solvation in general. Our calculations suggest that the steric contribution leads to a remarkable deviation from the popular linear response model in which the reaction potential changes linearly as a function of charge. In fact, the potential varies in a piecewise-linear fashion, i.e., with different proportionality constants depending on the sign of the charge. This discrepancy is significant even when the charge is completely buried, and holds for solutes larger than single atoms. Together, these mechanisms suggest that implicit-solvent models can be improved using a combination of affine response (an offset due to the static potential) and piecewise-linear response (due to the steric contribution).

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Computational Science X (CompX), Northeastern University, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic
Contributors: Bardhan, J. P., Jungwirth, P., Makowski, L.
Publication date: 28 Sep 2012
Peer-reviewed: Yes

Publication information

Journal: Journal of Chemical Physics
Volume: 137
Issue number: 12
Article number: 124101
ISSN (Print): 0021-9606
Ratings: 
  • Scopus rating (2012): CiteScore 2.86 SJR 1.832 SNIP 1.16
Original language: English
ASJC Scopus subject areas: Physics and Astronomy(all), Physical and Theoretical Chemistry
Source: Scopus
Source ID: 84867017908

Research output: Contribution to journalArticleScientificpeer-review

Fe2O3-TiO2 nanosystems by a hybrid PE-CVD/ALD approach: controllable synthesis, growth mechanism, and photocatalytic properties

Supported Fe2O3-TiO2 nanocomposites are fabricated by an original vapor phase synthetic strategy, consisting of the initial growth of Fe2O3 nanosystems on fluorine-doped tin oxide substrates by plasma enhanced-chemical vapor deposition, followed by atomic layer deposition of TiO2 overlayers with variable thickness, and final thermal treatment in air. A thorough characterization of the target systems is carried out by X-ray diffraction, atomic force microscopy, field emission-scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. High purity nanomaterials characterized by the co-presence of Fe2O3 (hematite) and TiO2 (anatase), with an intimate Fe2O3-TiO2 contact, are successfully obtained. In addition, photocatalytic tests demonstrate that, whereas both single-phase oxides do not show appreciable activity, the composite systems are able to degrade methyl orange aqueous solutions under simulated solar light, and even visible light, with an efficiency directly dependent on TiO2 overlayer thickness. This finding opens attractive perspectives for eventual applications in wastewater treatment.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Research group: Supramolecular photochemistry, Padova University, Padova University and INSTM, Department of Physics and Astronomy, University of Turku, Univ Antwerp, University of Antwerp, EMAT, CNR-IENI and INSTM, Department of Chemistry, Department of Chemical and Pharmaceutical Sciences, ICCOM-CNR Trieste Research Unit - INSTM Research Unit, Trieste University
Contributors: Barreca, D., Carraro, G., Warwick, M. E. A., Kaunisto, K., Gasparotto, A., Gombac, V., Sada, C., Turner, S., Van Tendeloo, G., Maccato, C., Fornasiero, P.
Number of pages: 8
Pages: 6219-6226
Publication date: 28 Aug 2015
Peer-reviewed: Yes

Publication information

Journal: CrystEngComm
Volume: 17
Issue number: 32
ISSN (Print): 1466-8033
Ratings: 
  • Scopus rating (2015): CiteScore 3.83 SJR 1.04 SNIP 0.98
Original language: English
ASJC Scopus subject areas: Chemistry(all), Materials Science(all), Condensed Matter Physics
Source: Scopus
Source ID: 84938522112

Research output: Contribution to journalArticleScientificpeer-review

Controlled Growth of Supported ZnO Inverted Nanopyramids with Downward Pointing Tips

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

General information

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

Publication information

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

Research output: Contribution to journalArticleScientificpeer-review

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 3.06 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 14.76 SJR 8.359 SNIP 3.064
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 4.59 SJR 1.597 SNIP 1.902
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

Encapsulation of secondary and tertiary ammonium salts by resorcinarenes and pyrogallarenes: The effect of size and charge concentration

The binding of different categories of alkyl ammonium (secondary and tertiary mono- and di-ammonium) salts with resorcinarenes and a pyrogallarene through weak interactions was analysed in all phases. 1H NMR spectroscopy and electrospray ionisation mass spectrometry were utilized in analysing the complexes in solution and in the gas phase, respectively. The 1H NMR titration studies in methanol-d4 reveal that the association constants for the 1:1 complexes vary according to the electronic properties of the hosts as well as the size, geometric orientation and charge concentration of the guest cations with binding constants of up to 950 M-1 in some cases. Mass spectrometry reveals 1:1 monomeric and 1:2 dimeric complexes in the gas phase. Six co-crystals, three of which are dimeric host-guest capsular assemblies, two open inclusion complexes and a pseudocapsular methanol solvate, were analysed in the solid state through single-crystal X-ray diffraction. The crystal structures confirm that the complexes are held together by multiple cation⋯π, CH⋯π and hydrogen bond interactions.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, University of Jyväskylä
Contributors: Beyeh, N. K., Pan, F., Valkonen, A., Rissanen, K.
Number of pages: 7
Pages: 1182-1188
Publication date: 7 Feb 2015
Peer-reviewed: Yes

Publication information

Journal: CrystEngComm
Volume: 17
Issue number: 5
ISSN (Print): 1466-8033
Ratings: 
  • Scopus rating (2015): CiteScore 3.83 SJR 1.04 SNIP 0.98
Original language: English
ASJC Scopus subject areas: Chemistry(all), Materials Science(all), Condensed Matter Physics
Source: Scopus
Source ID: 84921648549

Research output: Contribution to journalArticleScientificpeer-review

Construction of an Interconnected Nanostructured Carbon Black Network: Development of Highly Stretchable and Robust Elastomeric Conductors

In the present work, a strong filler-filler network of conductive carbon black was strategically established in an elastomer matrix, which leads to a unique combination of electrical and mechanical properties. The novelty of our composites was the development of a strong percolated morphology of nanostructured conducting carbon black particles by the incorporation of relatively large nonreinforcing spherical silica particles, inside the soft elastomer matrix. This technique allowed us to fabricate solution styrene butadiene rubber (S-SBR) composites with outstanding electrical conductivity of 40 S/m, tensile strength ∼10 MPa, and extensibility up to 200%. Furthermore, the electrical conductivity was strain-independent up to 50% elongation strain. The electrical conductivity was found to be unaltered after 2000 loading-unloading cycles. This is the first ever report of a robust elastomeric system with such high electrical conductivity where all the basic ingredients used were selected from well-known commercially available raw materials of rubber industry. This work directly manifests an industrially viable method for preparing high-performance elastic conductors that can be utilized in robust and flexible applications.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Materials Science, Engineering materials science and solutions (EMASS), Leibniz-Institut für Polymerforschung Dresden E.V., Technische Universität Dresden, Institut für Werkstoffwissenschaft, Institut für Polymerwerkstoffe E.V., Elkem AS, Silicon Materials
Contributors: Bhagavatheswaran, E. S., Parsekar, M., Das, A., Le, H. H., Wiessner, S., Stöckelhuber, K. W., Schmaucks, G., Heinrich, G.
Number of pages: 9
Pages: 21723-21731
Publication date: 17 Sep 2015
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry C
Volume: 119
Issue number: 37
ISSN (Print): 1932-7447
Ratings: 
  • Scopus rating (2015): CiteScore 4.68 SJR 1.886 SNIP 1.24
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Electronic, Optical and Magnetic Materials, Surfaces, Coatings and Films, Energy(all)
Source: Scopus
Source ID: 84941928016

Research output: Contribution to journalArticleScientificpeer-review

Tuning of nonlinear absorption in highly luminescent CdSe based quantum dots with core-shell and core/multi-shell architectures

We present our effort on an efficient way of tuning the nonlinear absorption mechanisms in ultra-small CdSe based quantum dots by implementing core-shell and core/multi-shell architectures. Depending on the size, architecture and composition of the QDs, these materials exhibited resonant and near-resonant nonlinear optical absorption properties such as saturable (SA) and reverse saturable (RSA) absorption for 5 ns pulses of 532 nm. These QDs exhibited a non-monotonic dependence of the effective two-photon absorption coefficient (β) under nanosecond excitation with a maximum value for a thinner shell. We obtained a nonlinear absorption enhancement of an order of magnitude by adopting the core-shell architecture compared to their individual counterparts. Interestingly, CdSe QDs exhibit SA and/or RSA depending on their size and show a switching over from SA to RSA as the input intensity increases. We explained the enhanced nonlinear absorption in core-shell QDs compared to their individual counterparts in view of enhanced local fields associated with the core-shell structure. Thus, the present nanostructured materials are excellent candidates as saturable absorbers and optical limiters.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, University of Johannesburg, Mahatma Gandhi University, Qatar University, Laboratory of Photonics, University of Concepcion
Contributors: Bhagyaraj, S., Perumbilavil, S., Udayabashkar, R., Mangalaraja, R. V., Thomas, S., Kalarikkal, N., Oluwafemi, O. S.
Number of pages: 11
Pages: 11424-11434
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Physical Chemistry Chemical Physics
Volume: 21
Issue number: 21
ISSN (Print): 1463-9076
Original language: English
ASJC Scopus subject areas: Physics and Astronomy(all), Physical and Theoretical Chemistry
Source: Scopus
Source ID: 85066623857

Research output: Contribution to journalArticleScientificpeer-review

Highly Oxygenated Organic Molecules (HOM) from Gas-Phase Autoxidation Involving Peroxy Radicals: A Key Contributor to Atmospheric Aerosol

Highly oxygenated organic molecules (HOM) are formed in the atmosphere via autoxidation involving peroxy radicals arising from volatile organic compounds (VOC). HOM condense on pre-existing particles and can be involved in new particle formation. HOM thus contribute to the formation of secondary organic aerosol (SOA), a significant and ubiquitous component of atmospheric aerosol known to affect the Earth's radiation balance. HOM were discovered only very recently, but the interest in these compounds has grown rapidly. In this Review, we define HOM and describe the currently available techniques for their identification/quantification, followed by a summary of the current knowledge on their formation mechanisms and physicochemical properties. A main aim is to provide a common frame for the currently quite fragmented literature on HOM studies. Finally, we highlight the existing gaps in our understanding and suggest directions for future HOM research.

General information

Publication status: Published
MoE publication type: A2 Review article in a scientific journal
Organisations: Physics, University of Helsinki, University of Chemical Technology, CNRS University of Lyon, Stockholm University, Institute for Atmospheric and Earth System Research/Physics, Lunds Universitet / Lunds Tekniska Högskola, Leibniz-Institut für Troposphärenforschung (TROPOS), California Institute of Technology, Forschungszentrum Jülich (FZJ), Institute of Physics, University of Tartu, Aerodyne Research Inc., Visiting Graduate Student in Department of Urban Design and Planning, University of Washington, Seattle, USA 1.1.2012-15.6.2012 (12.9.2011 alkaen), Carnegie Mellon University, Kobenhavns Universitet
Contributors: Bianchi, F., Kurtén, T., Riva, M., Mohr, C., Rissanen, M. P., Roldin, P., Berndt, T., Crounse, J. D., Wennberg, P. O., Mentel, T. F., Wildt, J., Junninen, H., Jokinen, T., Kulmala, M., Worsnop, D. R., Thornton, J. A., Donahue, N., Kjaergaard, H. G., Ehn, M.
Number of pages: 38
Pages: 3472-3509
Publication date: 27 Mar 2019
Peer-reviewed: Yes

Publication information

Journal: Chemical Reviews
Volume: 119
Issue number: 6
ISSN (Print): 0009-2665
Original language: English
ASJC Scopus subject areas: Chemistry(all)
Source: Scopus
Source ID: 85062513494

Research output: Contribution to journalReview ArticleScientificpeer-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 14.05 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 3.01 SJR 1.079 SNIP 0.88
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

Quantifying non-ergodic dynamics of force-free granular gases

Brownian motion is ergodic in the Boltzmann-Khinchin sense that long time averages of physical observables such as the mean squared displacement provide the same information as the corresponding ensemble average, even at out-of-equilibrium conditions. This property is the fundamental prerequisite for single particle tracking and its analysis in simple liquids. We study analytically and by event-driven molecular dynamics simulations the dynamics of force-free cooling granular gases and reveal a violation of ergodicity in this Boltzmann-Khinchin sense as well as distinct ageing of the system. Such granular gases comprise materials such as dilute gases of stones, sand, various types of powders, or large molecules, and their mixtures are ubiquitous in Nature and technology, in particular in Space. We treat - depending on the physical-chemical properties of the inter-particle interaction upon their pair collisions - both a constant and a velocity-dependent (viscoelastic) restitution coefficient ε. Moreover we compare the granular gas dynamics with an effective single particle stochastic model based on an underdamped Langevin equation with time dependent diffusivity. We find that both models share the same behaviour of the ensemble mean squared displacement (MSD) and the velocity correlations in the limit of weak dissipation. Qualitatively, the reported non-ergodic behaviour is generic for granular gases with any realistic dependence of ε on the impact velocity of particles.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Physics, Max-Planck Institute for the Physics of Complex Systems, Institute for Physics and Astronomy, University of Potsdam, Babes-Bolyai University, Faculty of Physics, Cluj-Napoca, Romania, Akhiezer Institute for Theoretical Physics, Kharkov Institute of Physics and Technology, M.V. Lomonosov Moscow State University
Contributors: Bodrova, A., Chechkin, A. V., Cherstvy, A. G., Metzler, R.
Number of pages: 8
Pages: 21791-21798
Publication date: 27 Jul 2015
Peer-reviewed: Yes

Publication information

Journal: Physical Chemistry Chemical Physics
Volume: 17
Issue number: 34
ISSN (Print): 1463-9076
Ratings: 
  • Scopus rating (2015): CiteScore 4.45 SJR 1.725 SNIP 1.188
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Physics and Astronomy(all)
Source: Scopus
Source ID: 84939865265

Research output: Contribution to journalArticleScientificpeer-review

Tribology of HVOF- and HVAF-sprayed WC-10Co4Cr hardmetal coatings: A comparative assessment

This paper provides a comprehensive assessment of the sliding and abrasive wear behaviour of WC-10Co4Cr hardmetal coatings, representative of the existing state-of-the-art. A commercial feedstock powder with two different particle size distributions was sprayed onto carbon steel substrates using two HVOF and two HVAF spray processes. Mild wear rates of <10-7mm3/(Nm) and friction coefficients of ≈0.5 were obtained for all samples in ball-on-disk sliding wear tests at room temperature against Al2O3 counterparts. WC-10Co4Cr coatings definitely outperform a reference electrolytic hard chromium coating under these test conditions. Their wear mechanisms include extrusion and removal of the binder matrix, with the formation of a wavy surface morphology, and brittle cracking. The balance of such phenomena is closely related to intra-lamellar features, and rather independent of those properties (e.g. indentation fracture toughness, elastic modulus) which mainly reflect large-scale inter-lamellar cohesion, as quantitatively confirmed by a principal component analysis. Intra-lamellar dissolution of WC into the matrix indeed increases the incidence of brittle cracking, resulting in slightly higher wear rates. At 400°C, some of the hardmetal coatings fail because of the superposition between tensile residual stresses and thermal expansion mismatch stresses (due to the difference between the thermal expansion coefficients of the steel substrate and of the hardmetal coating). Those which do not fail, on account of lower residual stresses, exhibit higher wear rates than at room temperature, due to oxidation of the WC grains.The resistance of the coatings against abrasive wear, assessed by dry sand-rubber wheel testing, is related to inter-lamellar cohesion, as proven by a principal component analysis of the collected dataset. Therefore, coatings deposited from coarse feedstock powders suffer higher wear loss than those obtained from fine powders, as brittle inter-lamellar detachment is caused by their weaker interparticle cohesion, witnessed by their systematically lower fracture toughness as well.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Materials Science, Research group: Surface Engineering, Engineering materials science and solutions (EMASS), University West, Dipartimento di Ingegneria Enzo Ferrari, University of Modena and Reggio Emilia, Fraunhofer-Institut für Werkstoff- und Strahltechnik (IWS), Fraunhofer-Institut für Keramische Technologien und Systeme (IKTS), Institut für Korrosionsschutz Dresden GmbH
Contributors: Bolelli, G., Berger, L. M., Börner, T., Koivuluoto, H., Lusvarghi, L., Lyphout, C., Markocsan, N., Matikainen, V., Nylén, P., Sassatelli, P., Trache, R., Vuoristo, P.
Number of pages: 20
Pages: 125-144
Publication date: 15 Mar 2015
Peer-reviewed: Yes

Publication information

Journal: Surface and Coatings Technology
Volume: 265
ISSN (Print): 0257-8972
Ratings: 
  • Scopus rating (2015): CiteScore 2.46 SJR 0.852 SNIP 1.37
Original language: English
ASJC Scopus subject areas: Chemistry(all), Condensed Matter Physics, Materials Chemistry, Surfaces, Coatings and Films, Surfaces and Interfaces
Keywords: Abrasive wear, Hardmetal, High velocity air-fuel (HVAF), High velocity oxy-fuel (HVOF), Sliding wear, WC-10Co4Cr
Source: Scopus
Source ID: 84925299473

Research output: Contribution to journalArticleScientificpeer-review

Soft graphoepitaxy for large area directed self-assembly of polystyrene-block-poly(dimethylsiloxane) block copolymer on nanopatterned poss substrates fabricated by nanoimprint lithography

Polyhedral oligomeric silsequioxane (POSS) derivatives have been successfully employed as substrates for graphoepitaxial directed self-assembly (DSA) of block copolymers (BCPs). Tailored POSS materials of tuned surface chemistry are subject to nanoimprint lithography (NIL) resulting in topographically patterned substrates with dimensions commensurate with the BCP block length. A cylinder forming polystyrene-block-polydimethylsiloxane (PS-b-PDMS) BCP is synthesized by sequential living anionic polymerization of styrene and hexamethylcyclotrisiloxane. The patterned POSS materials provide a surface chemistry and topography for DSA of this BCP and after solvent annealing the BCP shows well-ordered microphase segregation. The orientation of the PDMS cylinders to the substrate plane could be controlled within the trench walls by the choice of the POSS materials. The BCP patterns are successfully used as on-chip etch mask to transfer the pattern to underlying silicon substrate. This soft graphoepitaxy method shows highly promising results as a means to generate lithographic quality patterns by nonconventional methods and could be applied to both hard and soft substrates. The methodology might have application in several fields including device and interconnect fabrication, nanoimprint lithography stamp production, nanofluidic devices, lab-on-chip, or in other technologies requiring simple nanodimensional patterns. A methodology for fabricating highly ordered silicon nanostructures at a substrate is reported using nanoimprint lithography imprinted polyhedral oligomeric silsequioxane (POSS) substrates for graphoepitaxial directed self-assembly (DSA) of block copolymer (BCP). The patterned POSS materials provide a surface chemistry and topography for DSA of a cylinder forming polystyrene-block-polydimethylsiloxane BCP with well-ordered microphase segregation upon solvent annealing.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Frontier Photonics, Trinity College Dublin, University College Cork, Tyndall National Institute at National University of Ireland, Cork, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Laboratoire des Technologies de la Microelectronique (CNRS), Profactor GmbH, University Campus-Dourouti
Contributors: Borah, D., Rasappa, S., Salaun, M., Zellsman, M., Lorret, O., Liontos, G., Ntetsikas, K., Avgeropoulos, A., Morris, M. A.
Number of pages: 8
Pages: 3425-3432
Publication date: 1 Jun 2015
Peer-reviewed: Yes

Publication information

Journal: Advanced Functional Materials
Volume: 25
Issue number: 22
ISSN (Print): 1616-301X
Ratings: 
  • Scopus rating (2015): CiteScore 11.93 SJR 4.859 SNIP 2.439
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Biomaterials, Condensed Matter Physics, Electrochemistry
Keywords: block copolymer, directed self-assembly, nanoimprint lithography, pattern transfer, polyhedral oligomeric silsequioxane (POSS)
Source: Scopus
Source ID: 84930932614

Research output: Contribution to journalArticleScientificpeer-review

Block co-polymers for nanolithography: Rapid microwave annealing for pattern formation on substrates

The integration of block copolymer (BCP) self-assembled nanopattern formation as an alternative lithographic tool for nanoelectronic device fabrication faces a number of challenges such as defect densities, feature size, pattern transfer, etc. Key barriers are the nanopattern process times and pattern formation on current substrate stack layers such as hard masks (e.g., silicon nitride, Si3N4). We report a rapid microwave assisted solvothermal (in toluene environments) self-assembly and directed self-assembly of a polystyrene-blockpolydimethylsiloxane (PS-b-PDMS) BCP thin films on planar and topographically patterned Si3N4 substrates. Hexagonally arranged, cylindrical structures were obtained and good pattern ordering was achieved. Factors affecting BCP self-assembly, notably anneal time and temperature, were studied and seen to have significant effects. Graphoepitaxy within the topographical structures provided long range, translational alignment of the patterns. The effect of surface topography feature size and spacing was investigated. The solvothermal microwave based technique used to provide periodic order in the BCP patterns showed significant promise and ordering was achieved in much shorter periods than more conventional thermal and solvent annealing methods. The implications of the work in terms of manufacturing technologies are discussed.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Frontier Photonics, Trinity College Dublin, Materials Chemistry and Analysis Group, University College Cork, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Tyndall National Institute at National University of Ireland, Cork
Contributors: Borah, D., Rasappa, S., Senthamaraikannan, R., Holmes, J. D., Morris, M. A.
Number of pages: 18
Pages: 592-609
Publication date: 2015
Peer-reviewed: Yes

Publication information

Journal: Polymers
Volume: 7
Issue number: 4
ISSN (Print): 2073-4360
Ratings: 
  • Scopus rating (2015): CiteScore 3.37 SJR 0.888 SNIP 1.325
Original language: English
ASJC Scopus subject areas: Polymers and Plastics, Chemistry(all)
Keywords: Block copolymer, Graphoepitaxy, Microwave anneal, Nanoscale patterns, Plasma etching, Polymer brush, Self-assembly, Silicon nitride substrate, Solvothermal process
Source: Scopus
Source ID: 84930638018

Research output: Contribution to journalArticleScientificpeer-review

Soft-graphoepitaxy using nanoimprinted polyhedral oligomeric silsesquioxane substrates for the directed self-Assembly of PS-b-PDMS

We report here the fabrication of periodic sub-25 nm diameter size cylinder structures using block copolymer (BCP) directed self-Assembly on nanoimprinted topographically patterned substrates. Tailored polyhedral oligomeric silsesquioxanes (POSSs) films were spin coated onto silicon substrates and were patterned by nanoimprint lithography to produce topographies commensurable with the BCP domain spacing. The chemistry of the POSS was tuned to control the alignment and orientation of the BCP films. The substrates were used to direct the microphase separation (following toluene solvent annealing) of a hexagonal structure forming polystyrene-block-polydimethylsiloxane (PS-b-PDMS) having a domain spacing of 42.6 nm and PDMS cylinder widths of 23.7 nm. On more hydrophilic POSS substrates the cylinders were obtained parallel to the substrate plane and aligned with the topography. In contrast, in more hydrophobic POSS patterns, the cylinders align perpendicular to the substrate plane. The use of these methods for the nanofabrication of vias, nanofluidic devices or interconnect structures of sub-25 nm feature size is discussed.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Research group: Nanophotonics, Frontier Photonics, Trinity College Dublin, Edifici CM3, University College Cork, Tyndall National Institute at National University of Ireland, Cork, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Profactor GmbH, CNRS/UJF-Grenoble1/CEA LTM, Catalan Institute for Research and Advanced Studies (ICREA)
Contributors: Borah, D., Simao, C. D., Senthamaraikannan, R., Rasappa, S., Francone, A., Lorret, O., Salaun, M., Kosmala, B., Kehagias, N., Zelsmann, M., Sotomayor-Torres, C. M., Morris, M. A.
Number of pages: 10
Pages: 3512-3521
Publication date: Nov 2013
Peer-reviewed: Yes

Publication information

Journal: European Polymer Jounal
Volume: 49
Issue number: 11
ISSN (Print): 0014-3057
Ratings: 
  • Scopus rating (2013): CiteScore 3.43 SJR 1.087 SNIP 1.66
Original language: English
ASJC Scopus subject areas: Polymers and Plastics, Physics and Astronomy(all), Organic Chemistry
Keywords: Block copolymer-Polyhedral oligomeric silsesquioxanes, Directed self-Assembly, Graphoepitaxy, Nanoimprint lithography, Surface chemistry
Source: Scopus
Source ID: 84885020807

Research output: Contribution to journalArticleScientificpeer-review

Tuning PDMS brush chemistry by UV-O3 exposure for PS-b-PDMS microphase separation and directed self-assembly

The directed self-assembly (DSA) of block copolymer (BCP) thin films could enable a scalable, bottom-up alternative to photolithography for the generation of substrate features. The PS-b-PDMS (polystyrene-b-polydimethylsiloxane) system is attractive as it can be extended toward very small feature sizes as well as having two blocks that can be readily differentiated during pattern transfer. However, PS-b-PDMS offers a considerable challenge because of the chemical differences in the blocks which lead to poor surface-wetting, poor pattern orientation control, and structural instabilities. These challenges can be mitigated by careful definition of the interface chemistry between the substrate and the BCP. Here, we report controlled pattern formation in cylinder forming PS-b-PDMS system by use of a carefully controlled PDMS brush. Control of the brush was achieved using exposure to UV-O3 for varying time. It is demonstrated that this treatment enhances surface wetting and coverage of the BCP. The modified brushes also enable DSA of the BCP on topographically patterned substrates. UV-O3 exposure was also used to reveal the BCP structure and provide an in situ "hard mask" for pattern transfer to the substrate.

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
Contributors: Borah, D., Rasappa, S., Senthamaraikannan, R., Holmes, J. D., Morris, M. A.
Number of pages: 10
Pages: 8959-8968
Publication date: 16 Jul 2013
Peer-reviewed: Yes

Publication information

Journal: Langmuir
Volume: 29
Issue number: 28
ISSN (Print): 0743-7463
Ratings: 
  • Scopus rating (2013): CiteScore 4.55 SJR 1.896 SNIP 1.333
Original language: English
ASJC Scopus subject areas: Electrochemistry, Condensed Matter Physics, Surfaces and Interfaces, Materials Science(all), Spectroscopy
Source: Scopus
Source ID: 84880308592

Research output: Contribution to journalArticleScientificpeer-review

Molecularly functionalized silicon substrates for orientation control of the microphase separation of PS-b-PMMA and PS-b-PDMS block copolymer systems

The use of block copolymer (BCP) thin films to generate nanostructured surfaces for device and other applications requires precise control of interfacial energies to achieve the desired domain orientation. Usually, the surface chemistry is engineered through the use of homo- or random copolymer brushes grown or attached to the surface. Herein, we demonstrate a facile, rapid, and tunable approach to surface functionalization using a molecular approach based on ethylene glycol attachment to the surface. The effectiveness of the molecular approach is demonstrated for the microphase separation of PS-b-PMMA and PS-b-PDMS BCPs in thin films and the development of nanoscale features at the substrate.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Frontier Photonics, Tyndall National Institute at National University of Ireland, Cork, Selcuk University, Materials Chemistry and Analysis Group, University College Cork, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Collinstown Industrial Estate
Contributors: Borah, D., Ozmen, M., Rasappa, S., Shaw, M. T., Holmes, J. D., Morris, M. A.
Number of pages: 12
Pages: 2809-2820
Publication date: 5 Mar 2013
Peer-reviewed: Yes

Publication information

Journal: Langmuir
Volume: 29
Issue number: 9
ISSN (Print): 0743-7463
Ratings: 
  • Scopus rating (2013): CiteScore 4.55 SJR 1.896 SNIP 1.333
Original language: English
ASJC Scopus subject areas: Electrochemistry, Condensed Matter Physics, Surfaces and Interfaces, Materials Science(all), Spectroscopy
Source: Scopus
Source ID: 84874584704

Research output: Contribution to journalArticleScientificpeer-review

Semiclassical hybrid approach to condensed phase molecular dynamics: Application to the I2Kr17 cluster

We study the vibrational decoherence dynamics of an iodine molecule in a finite krypton cluster comprising the first solvation shell. A normal mode analysis allows us to successively increase the complexity of the description. For the ground state dynamics, comparison with experimental matrix results shows that already four degrees of freedom are sufficient to capture the main decoherence mechanism. For electronically excited iodine, we model the vibrational dynamics of initial Schrödinger cat-like states by the semiclassical hybrid dynamics [ Grossmann, F.J. Chem. Phys. 2006, 125, 014111 ] and full quantum calculations, where available. Good agreement of the results is found for a reduced model with three degrees of freedom. We find non-Gaussian distortions of the bath density matrix, which is a necessary condition, if Schrödinger catlike states in the bath are to be identified. However, in contrast to the experiment [ Segale, D.; et al. J. Chem. Phys. 2005, 122, 111104 ], we observe only incoherent superpositions of bath vibrational states.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Computational Science X (CompX), Vodafone Department of Mobile Communications Systems, Freie Universität Berlin, Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic
Contributors: Buchholz, M., Goletz, C. M., Grossmann, F., Schmidt, B., Heyda, J., Jungwirth, P.
Number of pages: 12
Pages: 11199-11210
Publication date: 26 Nov 2012
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry A
Volume: 116
Issue number: 46
ISSN (Print): 1089-5639
Ratings: 
  • Scopus rating (2012): CiteScore 2.78 SJR 1.513 SNIP 1.119
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry
Source: Scopus
Source ID: 84870038667

Research output: Contribution to journalArticleScientificpeer-review

Porous polybutylene succinate films enabling adhesion of human embryonic stem cell-derived retinal pigment epithelial cells (hESC-RPE)

In the last decade, several studies have shown that polybutylene succinate (PBSu)has a high potential as a biomaterial enabling cell adhesion and growth. In this study, porous PBSu films have been prepared by the breath figure method (BF)and by particulate leaching (PL), and characterized in terms of thickness, surface properties, diffusion capacity and in vitro stability. Because porous films are of high interest for tissue engineering of retinal pigment epithelium (RPE), the initial viability and adhesion of human embryonic stem cell-derived RPE onto the PBSu films was then evaluated. To the best of our knowledge, this is the first study on the adhesion behavior of hESC-RPE onto porous and biodegradable polymer surfaces. The results clearly demonstrated that the two manufacturing methods produced materials with very distinct properties. Films produced by BF expressively demonstrated the highest roughness and surface area, and the lowest water contact angle. These features likely contributed to increase the biocompatibility of the surface, particularly when coated with laminin and collagen IV, as observed by the improved cell viability, cell morphology, adhesion and production of extracellular matrix proteins. Altogether, our results showed not only that PBSu holds high potential in retinal tissue engineering, but also that the physical properties and biocompatibility of the material are highly dependent on the adopted casting method.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: BioMediTech, Tampere University, Tampere University Hospital
Contributors: Calejo, M. T., Haapala, A., Skottman, H., Kellomäki, M.
Number of pages: 10
Pages: 78-87
Publication date: 1 Sep 2019
Peer-reviewed: Yes

Publication information

Journal: European Polymer Journal
Volume: 118
ISSN (Print): 0014-3057
Original language: English
ASJC Scopus subject areas: Physics and Astronomy(all), Polymers and Plastics, Organic Chemistry, Materials Chemistry
Keywords: Biodegradable films, Breath figures, Cell adhesion, Polybutylene succinate, Retinal pigment epithelium
Source: Scopus
Source ID: 85066269398

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 10.8 SJR 5.954 SNIP 2.182
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 2.24 SJR 0.579 SNIP 0.772
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

Ergodicity breaking and particle spreading in noisy heterogeneous diffusion processes

We study noisy heterogeneous diffusion processes with a position dependent diffusivity of the form D(x) ∼ D<inf>0</inf>|x|α<inf>0</inf> in the presence of annealed and quenched disorder of the environment, corresponding to an effective variation of the exponent α in time and space. In the case of annealed disorder, for which effectively α<inf>0</inf> = α<inf>0</inf>(t), we show how the long time scaling of the ensemble mean squared displacement (MSD) and the amplitude variation of individual realizations of the time averaged MSD are affected by the disorder strength. For the case of quenched disorder, the long time behavior becomes effectively Brownian after a number of jumps between the domains of a stratified medium. In the latter situation, the averages are taken over both an ensemble of particles and different realizations of the disorder. As physical observables, we analyze in detail the ensemble and time averaged MSDs, the ergodicity breaking parameter, and higher order moments of the time averages.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Physics, Institute for Physics and Astronomy, University of Potsdam
Contributors: Cherstvy, A. G., Metzler, R.
Publication date: 14 Apr 2015
Peer-reviewed: Yes

Publication information

Journal: Journal of Chemical Physics
Volume: 142
Issue number: 14
Article number: 144105
ISSN (Print): 0021-9606
Ratings: 
  • Scopus rating (2015): CiteScore 1.98 SJR 1.255 SNIP 1.042
Original language: English
ASJC Scopus subject areas: Physics and Astronomy(all), Physical and Theoretical Chemistry
Source: Scopus
Source ID: 84927611195

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 14.75 SJR 7.468 SNIP 2.634
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

Syndecan-4 tunes cell mechanics by activating the kindlin-integrin-RhoA pathway

Extensive research over the past decades has identified integrins to be the primary transmembrane receptors that enable cells to respond to external mechanical cues. We reveal here a mechanism whereby syndecan-4 tunes cell mechanics in response to localized tension via a coordinated mechanochemical signalling response that involves activation of two other receptors: epidermal growth factor receptor and β1 integrin. Tension on syndecan-4 induces cell-wide activation of the kindlin-2/β1 integrin/RhoA axis in a PI3K-dependent manner. Furthermore, syndecan-4-mediated tension at the cell–extracellular matrix interface is required for yes-associated protein activation. Extracellular tension on syndecan-4 triggers a conformational change in the cytoplasmic domain, the variable region of which is indispensable for the mechanical adaptation to force, facilitating the assembly of a syndecan-4/α-actinin/F-actin molecular scaffold at the bead adhesion. This mechanotransduction pathway for syndecan-4 should have immediate implications for the broader field of mechanobiology.

General information

Publication status: Accepted/In press
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Imperial College London, Queen Mary University of London, Tampere University, Fimlab Laboratories, Helsinki University, University of Tampere
Contributors: Chronopoulos, A., Thorpe, S. D., Cortes, E., Lachowski, D., Rice, A. J., Mykuliak, V. V., Róg, T., Lee, D. A., Hytönen, V. P., del Río Hernández, A. E.
Publication date: 2020
Peer-reviewed: Yes

Publication information

Journal: Nature Materials
ISSN (Print): 1476-1122
Original language: English
ASJC Scopus subject areas: Chemistry(all), Materials Science(all), Condensed Matter Physics, Mechanics of Materials, Mechanical Engineering
Source: Scopus
Source ID: 85077339980

Research output: Contribution to journalArticleScientificpeer-review

Self-assembly of polystyrene-block-poly(4-vinylpyridine) block copolymer on molecularly functionalized silicon substrates: Fabrication of inorganic nanostructured etchmask for lithographic use

Block copolymers (BCPs) are seen as a possible cost effective complementary technique to traditional lithography currently used in the semiconductor industry. This unconventional approach has received increased attention in recent years as a process capable of facilitating the ever decreasing device size demanded. Control over microdomain orientation and enhancing long range order are key aspects for the utility of BCPs for future lithographic purposes. This paper provides an efficient route for the fabrication of highly ordered nanostructures suitable for such application. We investigate the significant effect of surface treatment regarding the self-assembly process of polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) by employing an ethylene glycol layer, producing well defined perpendicular P4VP cylinders with long range order over large surface areas. Nanopores are generated through surface reconstruction using a preferential solvent, which allows for the incorporation of an inorganic moiety. Treatment of this pattern with UV/Ozone leads to formation of well-ordered iron oxide nanodots with a pitch of ∼26 nm. Furthermore, high aspect ratio silicon nanopillars result following pattern transfer (using Ar/O2).

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Frontier Photonics, Tyndall National Institute at National University of Ireland, Cork, Trinity College Dublin, University College Cork, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN)
Contributors: Cummins, C., Borah, D., Rasappa, S., Chaudhari, A., Ghoshal, T., O'Driscoll, B. M. D., Carolan, P., Petkov, N., Holmes, J. D., Morris, M. A.
Number of pages: 11
Pages: 7941-7951
Publication date: 21 Dec 2013
Peer-reviewed: Yes

Publication information

Journal: Journal of Materials Chemistry C
Volume: 1
Issue number: 47
ISSN (Print): 2050-7534
Original language: English
ASJC Scopus subject areas: Chemistry(all), Materials Chemistry
Source: Scopus
Source ID: 84887902210

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 14.76 SJR 8.359 SNIP 3.064
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 12.71 SJR 6.211 SNIP 2.396
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

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 3.9 SJR 1.349 SNIP 1.216
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

Efficient production of NV colour centres in nanodiamonds using high-energy electron irradiation

Nanodiamond powders with an average size of 50 nm have been irradiated using high-energy electron beam. After annealing and chemical treatment, nanodiamond colloidal solutions were obtained and deposited on silica coverslips by spin-coating. The fluorescence of nanodiamonds was studied by confocal microscopy together with atomic force microscopy. We evaluated the proportion of luminescent nanodiamonds as a function of the irradiation duration and showed that large quantities, exceeding hundreds of mg, of luminescent nanodiamonds can be produced within 1 h of electron irradiation.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Laboratoire de Physique Quantique et Moléculaire
Contributors: Dantelle, G., Slablab, A., Rondin, L., Lainé, F., Carrel, F., Bergonzo, P., Perruchas, S., Gacoin, T., Treussart, F., Roch, J. F.
Number of pages: 4
Pages: 1655-1658
Publication date: Sep 2010
Peer-reviewed: Yes

Publication information

Journal: Journal of Luminescence
Volume: 130
Issue number: 9
ISSN (Print): 0022-2313
Ratings: 
  • Scopus rating (2010): SJR 0.909 SNIP 1.103
Original language: English
ASJC Scopus subject areas: Atomic and Molecular Physics, and Optics, Condensed Matter Physics, Chemistry(all), Biochemistry, Biophysics
Keywords: Diamond, Luminescence, NV centre
Source: Scopus
Source ID: 77955274026

Research output: Contribution to journalArticleScientificpeer-review

A novel thermotropic elastomer based on highly-filled LDH-SSB composites

Elastomeric composites are prepared based on solution styrene butadiene elastomer and zinc-aluminium layered double hydroxides (LDH), using a conventional sulphur cure system. Up to 100 parts per hundred rubber of LDH are incorporated into the elastomer matrix. The composites exhibit an interesting phenomenon of thermoreversible transparency, i.e. the transparent sample becomes opaque at warm condition and restores the transparency at room temperature. The transparency is found to be increased as the amount of LDH was increased. The addition of LDH gradually improved the mechanical, dynamic mechanical performance and thermal stability of the base elastomer. These developped elastomers could be utilised as smart materials in different applications

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Engineering materials science and solutions (EMASS), Leibniz-Institut für Polymerforschung Dresden E.V., Vodafone Department of Mobile Communications Systems
Contributors: Das, A., George, J. J., Kutlu, B., Leuteritz, A., Wang, D. Y., Rooj, S., Jurk, R., Rajeshbabu, R., Stöckelhuber, K. W., Galiatsatos, V., Heinrich, G.
Number of pages: 6
Pages: 337-342
Publication date: 27 Feb 2012
Peer-reviewed: Yes

Publication information

Journal: Macromolecular Rapid Communications
Volume: 33
Issue number: 4
ISSN (Print): 1022-1336
Ratings: 
  • Scopus rating (2012): CiteScore 4.7 SJR 2.096 SNIP 1.251
Original language: English
ASJC Scopus subject areas: Organic Chemistry, Materials Chemistry, Polymers and Plastics
Source: Scopus
Source ID: 84863149624

Research output: Contribution to journalArticleScientificpeer-review

Preparation of zinc oxide free, transparent rubber nanocomposites using a layered double hydroxide filler

A layered double hydroxide (LDH) mineral filler particle has been designed and employed in rubber vulcanization to prepare a more environmentally friendly rubber composite. The LDH delivers zinc ions in the vulcanization process as accelerators, stearate anions as activators and simultaneously the mineral sheets act as a nanofiller to reinforce the rubber matrix whilst totally replacing the separate zinc oxide (ZnO) and stearic acid conventionally used in the formulation of rubber. This method leads to a significant reduction (nearly 10 times) of the zinc level and yields excellent transparent properties in the final rubber product. The morphological characterization, rheometric curing behaviour, mechanical properties and uniaxial multi-hysteresis behaviours of the resultant rubber/LDH nanocomposite are studied in this paper.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Engineering materials science and solutions (EMASS), Leibniz-Institut für Polymerforschung Dresden E.V., Durham University
Contributors: Das, A., Wang, D. Y., Leuteritz, A., Subramaniam, K., Greenwell, H. C., Wagenknecht, U., Heinrich, G.
Number of pages: 7
Pages: 7194-7200
Publication date: 28 May 2011
Peer-reviewed: Yes

Publication information

Journal: Journal of Materials Chemistry
Volume: 21
Issue number: 20
ISSN (Print): 0959-9428
Ratings: 
  • Scopus rating (2011): SJR 2.614 SNIP 1.539
Original language: English
ASJC Scopus subject areas: Chemistry(all), Materials Chemistry
Source: Scopus
Source ID: 79955619174

Research output: Contribution to journalArticleScientificpeer-review

Temperature scanning stress relaxation of an autonomous self-healing elastomer containing non-covalent reversible network junctions

In this work, we report about the mechanical relaxation characteristics of an intrinsically self-healable imidazole modified commercial rubber. This kind of self-healing rubber was prepared by melt mixing of 1-butyl imidazole with bromo-butyl rubber (bromine modified isoprene-isobutylene copolymer, BIIR). By this melt mixing process, the reactive allylic bromine of bromo-butyl rubber was converted into imidazole bromide salt. The resulting development of an ionic character to the polymer backbone leads to an ionic association of the groups which ultimately results to the formation of a network structure of the rubber chains. The modified BIIR thus behaves like a robust crosslinked rubber and shows unusual self-healing properties. The non-covalent reversible network has been studied in detail with respect to stress relaxation experiments, scanning electron microscopic and X-ray scattering.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science, Vodafone Department of Mobile Communications Systems, University of Applied Sciences Osnabrück, Leibniz-Institut für Polymerforschung Dresden E.V.
Contributors: Das, A., Sallat, A., Böhme, F., Sarlin, E., Vuorinen, J., Vennemann, N., Heinrich, G., Stöckelhuber, K. W.
Publication date: 19 Jan 2018
Peer-reviewed: Yes

Publication information

Journal: Polymers
Volume: 10
Issue number: 1
Article number: 94
ISSN (Print): 2073-4360
Ratings: 
  • Scopus rating (2018): CiteScore 3.25 SJR 0.724 SNIP 1.057
Original language: English
ASJC Scopus subject areas: Chemistry(all), Polymers and Plastics
Keywords: Bromo-butyl rubber, Ionic modification, Reversible polymer network, Self-healing, Stress-relaxation
Electronic versions: 
Source: Scopus
Source ID: 85040774453

Research output: Contribution to journalArticleScientificpeer-review

Inverted critical adsorption of polyelectrolytes in confinement

What are the fundamental laws for the adsorption of charged polymers onto oppositely charged surfaces, for convex, planar, and concave geometries? This question is at the heart of surface coating applications, various complex formation phenomena, as well as in the context of cellular and viral biophysics. It has been a long-standing challenge in theoretical polymer physics; for realistic systems the quantitative understanding is however often achievable only by computer simulations. In this study, we present the findings of such extensive Monte-Carlo in silico experiments for polymer-surface adsorption in confined domains. We study the inverted critical adsorption of finite-length polyelectrolytes in three fundamental geometries: planar slit, cylindrical pore, and spherical cavity. The scaling relations extracted from simulations for the critical surface charge density σ<inf>c</inf> - defining the adsorption-desorption transition - are in excellent agreement with our analytical calculations based on the ground-state analysis of the Edwards equation. In particular, we confirm the magnitude and scaling of σ<inf>c</inf> for the concave interfaces versus the Debye screening length 1/κ and the extent of confinement a for these three interfaces for small κa values. For large κa the critical adsorption condition approaches the known planar limit. The transition between the two regimes takes place when the radius of surface curvature or half of the slit thickness a is of the order of 1/κ. We also rationalize how σ<inf>c</inf>(κ) dependence gets modified for semi-flexible versus flexible chains under external confinement. We examine the implications of the chain length for critical adsorption - the effect often hard to tackle theoretically - putting an emphasis on polymers inside attractive spherical cavities. The applications of our findings to some biological systems are discussed, for instance the adsorption of nucleic acids onto the inner surfaces of cylindrical and spherical viral capsids.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Physics, Institute for Physics and Astronomy, University of Potsdam, Sao Paulo State University
Contributors: De Carvalho, S. J., Metzler, R., Cherstvy, A. G.
Number of pages: 14
Pages: 4430-4443
Publication date: 14 Jun 2015
Peer-reviewed: Yes

Publication information

Journal: Soft Matter
Volume: 11
Issue number: 22
ISSN (Print): 1744-683X
Ratings: 
  • Scopus rating (2015): CiteScore 3.97 SJR 1.634 SNIP 1.24
Original language: English
ASJC Scopus subject areas: Chemistry(all), Condensed Matter Physics
Source: Scopus
Source ID: 84930640692

Research output: Contribution to journalArticleScientificpeer-review

Structural information content of networks: Graph entropy based on local vertex functionals

In this paper we define the structural information content of graphs as their corresponding graph entropy. This definition is based on local vertex functionals obtained by calculating j-spheres via the algorithm of Dijkstra. We prove that the graph entropy and, hence, the local vertex functionals can be computed with polynomial time complexity enabling the application of our measure for large graphs. In this paper we present numerical results for the graph entropy of chemical graphs and discuss resulting properties.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: TU Vienna, Department of Biostatistics, Visiting Graduate Student in Department of Urban Design and Planning, University of Washington, Seattle, USA 1.1.2012-15.6.2012 (12.9.2011 alkaen), Department of Genome Sciences
Contributors: Dehmer, M., Emmert-Streib, F.
Number of pages: 8
Pages: 131-138
Publication date: Apr 2008
Peer-reviewed: Yes

Publication information

Journal: Computational Biology and Chemistry
Volume: 32
Issue number: 2
ISSN (Print): 1476-9271
Ratings: 
  • Scopus rating (2008): SJR 0.795 SNIP 0.687
Original language: English
ASJC Scopus subject areas: Biochemistry, Structural Biology, Analytical Chemistry, Physical and Theoretical Chemistry
Keywords: Chemical graph theory, Gene networks, Graph entropy, Information theory, Structural information content
Source: Scopus
Source ID: 40049085450

Research output: Contribution to journalArticleScientificpeer-review

Quantifying structural complexity of graphs: Information measures in mathematical chemistry

In this chapter, we give a conceptional view about information measures for graphs which can be used to quantify their structural complexity. We focus on treating such measures in the context of mathematical chemistry but we want to mention that those are also applicable for arbitrary complex networks. Besides reviewing the most known information indices often used in chemical graph theory, we propose an information functional that is based on degree-degree associations in a graph. This leads us to a parametric graph entropy measure to quantify the structural information content of a graph. A brief numerical example shows how the measure can be calculated explicitly.

General information

Publication status: Published
MoE publication type: A3 Part of a book or another research book
Organisations: Research Community on Data-to-Decision (D2D), Institute for Bioinformatics and Translational Research, Computational Biology and Machine Learning Lab., Faculty of Medicine, Health and Life Sciences, Queen's University, Belfast, Northern Ireland, Tomsk Polytechnic University, TU Vienna
Contributors: Dehmer, M., Emmert-Streib, F., Tsoy, Y. R., Varmuza, K.
Number of pages: 19
Pages: 479-497
Publication date: 2011

Host publication information

Title of host publication: Quantum Frontiers of Atoms and Molecules
Publisher: Nova Science Publishers, Inc.
Editor: Putz, M. V.
ISBN (Print): 9781616681586
ASJC Scopus subject areas: Chemistry(all)
Source: Scopus
Source ID: 84895219944

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

The structural information content of chemical networks

We present an information-theoretic method to measure the structural information content of networks and apply it to chemical graphs. As a result, we find that our entropy measure is more general than classical information indices known in mathematical and computational chemistry. Further, we demonstrate that our measure reflects the essence of molecular branching meaningfully by determining the structural information content of some chemical graphs numerically.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: TU Vienna, Department of Biostatistics, Visiting Graduate Student in Department of Urban Design and Planning, University of Washington, Seattle, USA 1.1.2012-15.6.2012 (12.9.2011 alkaen)
Contributors: Dehmer, M., Emmert-Streib, F.
Number of pages: 4
Pages: 155-158
Publication date: Mar 2008
Peer-reviewed: Yes

Publication information

Journal: Zeitschrift fur Naturforschung Section A: A Journal of Physical Sciences
Volume: 63
Issue number: 3-4
ISSN (Print): 0932-0784
Ratings: 
  • Scopus rating (2008): SJR 0.318 SNIP 0.78
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry
Keywords: Chemical graph theory, Graph entropy, Information theory, Structural information content
Source: Scopus
Source ID: 46649096825

Research output: Contribution to journalArticleScientificpeer-review

Global analysis of human nonreceptor tyrosine kinase specificity using high-density peptide microarrays

Protein kinases phosphorylate substrates in the context of specific phosphorylation site sequence motifs. The knowledge of the specific sequences that are recognized by kinases is useful for mapping sites of phosphorylation in protein substrates and facilitates the generation of model substrates to monitor kinase activity. Here, we have adapted a positional scanning peptide library method to a microarray format that is suitable for the rapid determination of phosphorylation site motifs for tyrosine kinases. Peptide mixtures were immobilized on glass slides through a layer of a tyrosine-free Y33F mutant avidin to facilitate the analysis of phosphorylation by radiolabel assay. A microarray analysis provided qualitatively similar results in comparison with the solution phase peptide library "macroarray" method. However, much smaller quantities of kinases were required to phosphorylate peptides on the microarrays, which thus enabled a proteome scale analysis of kinase specificity. We illustrated this capability by microarray profiling more than 80% of the human nonreceptor tyrosine kinases (NRTKs). Microarray results were used to generate a universal NRTK substrate set of 11 consensus peptides for in vitro kinase assays. Several substrates were highly specific for their cognate kinases, which should facilitate their incorporation into kinase-selective biosensors.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Multi-scaled biodata analysis and modelling (MultiBAM), Yale School of Medicine, Bio21 Molecular Science and Biotechnology Institute, Fimlab Laboratories Ltd
Contributors: Deng, Y., Alicea-Velázquez, N. L., Bannwarth, L., Lehtonen, S. I., Boggon, T. J., Cheng, H. C., Hytönen, V. P., Turk, B. E.
Number of pages: 8
Pages: 4339-4346
Publication date: 3 Oct 2014
Peer-reviewed: Yes

Publication information

Journal: Journal of Proteome Research
Volume: 13
Issue number: 10
ISSN (Print): 1535-3893
Ratings: 
  • Scopus rating (2014): CiteScore 4.64 SJR 1.959 SNIP 1.158
Original language: English
ASJC Scopus subject areas: Chemistry(all), Biochemistry
Keywords: drug discovery, enzyme specificity, kinase inhibitors, nonreceptor tyrosine kinases, peptide libraries, peptide microarrays, protein kinases
Source: Scopus
Source ID: 84907855794

Research output: Contribution to journalArticleScientificpeer-review

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

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

General information

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

Publication information

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

Research output: Contribution to journalArticleScientificpeer-review

Synthesis, crystal structure, physico-chemical characterization and dielectric properties of a new hybrid material, 1-Ethylpiperazine-1,4-diium tetrachlorocadmate


General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Carthage University, Laboratoire de chimie des Matériaux, Faculté des Sciences de Bizerte, Université de Carthage
Contributors: Dhieb, A. C., Valkonen, A., Rzaigui, M., Smirani, W.
Number of pages: 7
Pages: 50-56
Publication date: 15 Dec 2015
Peer-reviewed: Yes
Early online date: 22 Aug 2015

Publication information

Journal: Journal of Molecular Structure
Volume: 1102
ISSN (Print): 0022-2860
Ratings: 
  • Scopus rating (2015): CiteScore 1.7 SJR 0.446 SNIP 0.822
Original language: English
ASJC Scopus subject areas: Spectroscopy, Analytical Chemistry, Inorganic Chemistry, Organic Chemistry
Keywords: Dielectric properties, IR-Raman spectroscopies, NMR spectroscopy, Phase transition, Photoluminescence, X-Ray diffraction
Source: Scopus
Source ID: 84940482600

Research output: Contribution to journalArticleScientificpeer-review

Effect of surface morphology of poly(ïμ-caprolactone) scaffolds on adipose stem cell adhesion and proliferation

Summary The effect of the surface morphology of flat poly(Ïμ- caprolactone) (PCL) scaffolds on human adipose stem cell (hASC) adherence and proliferation was studied. During fabrication of the scaffolds by phase inversion, the employment of different non-solvents (water (W), ethanol (EtOH) or isopropanol (IPA)) led to distinct surface morphologies. It was found that PCL scaffolds fabricated using IPA as a non-solvent had a higher roughness and porosity compared to the other groups. Moreover, during culturing of hASCs under static conditions, best cell attachment, spreading and growth were observed on the PCL scaffold. Our results show the potential of PCL scaffolds prepared using IPA as a non-solvent for especially soft tissue engineering applications.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Integrated Technologies for Tissue Engineering Research (ITTE), University of Twente, University of Groningen
Contributors: Diban, N., Haimi, S. P., Bolhuis-Versteeg, L., Teixeira, S., Miettinen, S., Poot, A. A., Grijpma, D. W., Stamatialis, D.
Number of pages: 7
Pages: 126-132
Publication date: Dec 2013
Peer-reviewed: Yes

Publication information

Journal: Macromolecular symposia
Volume: 334
Issue number: 1
ISSN (Print): 1022-1360
Ratings: 
  • Scopus rating (2013): CiteScore 0.71 SJR 0.326 SNIP 0.388
Original language: English
ASJC Scopus subject areas: Organic Chemistry, Materials Chemistry, Polymers and Plastics, Condensed Matter Physics
Keywords: morphology, phase inversion, poly(Ïμ-caprolactone), roughness, scaffold porosity
Source: Scopus
Source ID: 84890745371

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 5.38 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 5.68 SJR 1.676 SNIP 1.895
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

Adsorption of furfural from torrefaction condensate using torrefied biomass

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

General information

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

Publication information

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

Research output: Contribution to journalArticleScientificpeer-review

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

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

General information

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

Publication information

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

Research output: Contribution to journalArticleScientificpeer-review

Detection and characterization at nM concentration of oligomers formed by hIAPP, Aβ(1-40) and their equimolar mixture using SERS and MD simulations

We report a structural investigation on IAPP, Aβ(1-40) and their equi-molar mixture aggregation pathway at nano-molar concentration using the Surface Enhanced Raman Spectroscopy (SERS) effect induced by silver metal colloids prepared by laser processes in solution and molecular dynamics simulations. Our data show the ability of silver NPs coupled with SERS to detect secondary structures of IAPP, Aβ(1-40) and their 1:1 molar ratio mixture in the oligomeric state. The preparation of silver colloids shows superior performance with respect to chemically prepared nano-particles. SERS spectroscopy shows both selectivity and sensitivity in detecting the secondary structures of hIAPP and Aβ(1-40) and to recognize both proteins in their mixture. On the other hand, molecular dynamics simulations confirm SERS structural data and the given atomistic details about the structural organization of IAPP and Aβ(1-40) oligomers. Our study shows an inhomogeneity in the chemical composition of IAPP/Aβ(1-40) oligomer aggregates.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Department of Chemical Sciences
Contributors: D'Urso, L., Condorelli, M., Puglisi, O., Tempra, C., Lolicato, F., Compagnini, G., La Rosa, C.
Number of pages: 9
Pages: 20588-20596
Publication date: 2018
Peer-reviewed: Yes

Publication information

Journal: Physical Chemistry Chemical Physics
Volume: 20
Issue number: 31
ISSN (Print): 1463-9076
Ratings: 
  • Scopus rating (2018): CiteScore 3.69 SJR 1.31 SNIP 0.981
Original language: English
ASJC Scopus subject areas: Physics and Astronomy(all), Physical and Theoretical Chemistry
Source: Scopus
Source ID: 85051509553

Research output: Contribution to journalArticleScientificpeer-review

PEGylated liposomes as carriers of hydrophobic porphyrins

Sterically stabilized liposomes (SSLs) (PEGylated liposomes) are applied as effective drug delivery vehicles. Understanding the interactions between hydrophobic compounds and PEGylated membranes is therefore important to determine the effectiveness of PEGylated liposomes for delivery of drugs or other bioactive substances. In this study, we have combined fluorescence quenching analysis (FQA) experiments and all-atom molecular dynamics (MD) simulations to study the effect of membrane PEGylation on the location and orientation of 5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin (p-THPP) that has been used in our study as a model hydrophobic compound. First, we consider the properties of p-THPP in the presence of different fluid phosphatidylcholine bilayers that we use as model systems for protein-free cell membranes. Next, we studied the interaction between PEGylated membranes and p-THPP. Our MD simulation results indicated that the arrangement of p-THPP within zwitterionic membranes is dependent on their free volume, and p-THPP solubilized in PEGylated liposomes is localized in two preferred positions: deep within the membrane (close to the center of the bilayer) and in the outer PEG corona (p-THPP molecules being wrapped with the polymer chains). Fluorescence quenching methods confirmed the results of atomistic MD simulations and showed two populations of p-THPP molecules as in MD simulations. Our results provide both an explanation for the experimental observation that PEGylation improves the drug-loading efficiency of membranes and also a more detailed molecular-level description of the interactions between porphyrins and lipid membranes.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Physics, Research area: Computational Physics, Research group: Biological Physics and Soft Matter, Computational Science X (CompX), University of Cambridge, Faculty of Physics and Chemistry, Helsinki University, University of Southern Denmark, Jagiellonian University, Centre for Drug Research, Faculty of Pharmacy
Contributors: Dzieciuch, M., Rissanen, S., Szydłowska, N., Bunker, A., Kumorek, M., Jamróz, D., Vattulainen, I., Nowakowska, M., Róg, T., Kepczynski, M.
Number of pages: 12
Pages: 6646-6657
Publication date: 4 Jun 2015
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry Part B
Volume: 119
Issue number: 22
ISSN (Print): 1520-6106
Ratings: 
  • Scopus rating (2015): CiteScore 3.25 SJR 1.335 SNIP 1.058
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Materials Chemistry, Surfaces, Coatings and Films
Source: Scopus
Source ID: 84930960276

Research output: Contribution to journalArticleScientificpeer-review

A microscopic view of the mechanisms of active transport across the cellular membrane

Membrane transporters are molecular machines that couple active transport of their specific substrates to various sources of cellular energy through a set of highly coordinated protein conformational changes. The alternating-access mechanism of transport in these proteins, which ensures that the substrate is only accessible from one side of the membrane at any given time, relies on complex and global protein conformational changes that are also closely coupled to molecular events such as substrate binding and translocation. In this review, we describe the application of advanced molecular modeling and simulation technologies to a number of membrane transport proteins studied in our laboratory. The goal is to demonstrate the power of the methods in describing functionally relevant molecular events ranging from more localized events such as substrate binding and gating motions to large, global protein conformational changes governing the transition of the protein between major functional states.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Computational Science X (CompX), Department of Biochemistry, Univ Illinois, University of Illinois System, University of Illinois Urbana-Champaign, Frederick Seitz Mat Res Lab, Dept Mat Sci & Engn
Contributors: Enkavi, G., Li, J., Wen, P., Thangapandian, S., Moradi, M., Jiang, T., Han, W., Tajkhorshid, E.
Number of pages: 49
Pages: 77-125
Publication date: 2014
Peer-reviewed: Yes

Publication information

Journal: Annual Reports in Computational Chemistry
Volume: 10
ISSN (Print): 1574-1400
Ratings: 
  • Scopus rating (2014): CiteScore 1.25 SJR 0.74 SNIP 0.985
Original language: English
ASJC Scopus subject areas: Chemistry(all), Computational Mathematics
Keywords: Conformational changes, Membrane transporters, Molecular dynamics, Nonequilibrium simulation, Primary transporters, Secondary transporters, Substrate binding
Source: Scopus
Source ID: 84919386963

Research output: Contribution to journalArticleScientificpeer-review

Multiscale Simulations of Biological Membranes: The Challenge To Understand Biological Phenomena in a Living Substance

Biological membranes are tricky to investigate. They are complex in terms of molecular composition and structure, functional over a wide range of time scales, and characterized by nonequilibrium conditions. Because of all of these features, simulations are a great technique to study biomembrane behavior. A significant part of the functional processes in biological membranes takes place at the molecular level; thus computer simulations are the method of choice to explore how their properties emerge from specific molecular features and how the interplay among the numerous molecules gives rise to function over spatial and time scales larger than the molecular ones. In this review, we focus on this broad theme. We discuss the current state-of-the-art of biomembrane simulations that, until now, have largely focused on a rather narrow picture of the complexity of the membranes. Given this, we also discuss the challenges that we should unravel in the foreseeable future. Numerous features such as the actin-cytoskeleton network, the glycocalyx network, and nonequilibrium transport under ATP-driven conditions have so far received very little attention; however, the potential of simulations to solve them would be exceptionally high. A major milestone for this research would be that one day we could say that computer simulations genuinely research biological membranes, not just lipid bilayers.

General information

Publication status: Published
MoE publication type: A2 Review article in a scientific journal
Organisations: Research group: Biological Physics and Soft Matter, Research area: Computational Physics, Physics, Helsinki University, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, MEMPHYS-Center for Biomembrane Physics
Contributors: Enkavi, G., Javanainen, M., Kulig, W., Róg, T., Vattulainen, I.
Number of pages: 168
Pages: 5607-5774
Publication date: 8 May 2019
Peer-reviewed: Yes

Publication information

Journal: Chemical Reviews
Volume: 119
Issue number: 9
ISSN (Print): 0009-2665
Original language: English
ASJC Scopus subject areas: Chemistry(all)
Electronic versions: 

Bibliographical note

EXT="Enkavi, Giray"
EXT="Kulig, Waldemar"

Source: Scopus
Source ID: 85063142928

Research output: Contribution to journalReview ArticleScientificpeer-review

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

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

General information

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

Publication information

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

Research output: Contribution to journalArticleScientificpeer-review

Exploring the role of stearic acid in modified zinc aluminum layered double hydroxides and their acrylonitrile butadiene rubber nanocomposites

The proposed study attempted to explore the role of stearic acid modification on the properties of zinc-aluminum based layered double hydroxides (LDH) and their composites with acrylonitrile butadiene rubber (NBR). Three distinctive LDH systems were adapted for such comparison; an unmodified LDH and two stearic acid modified LDH. The use of zinc oxide and stearic acid in the rubber formulation was avoided as the modified LDH would be able to deliver the necessary activators for the vulcanization process. Emphasis was predominantly given to reconnoiter the merits of stearic acid modification on the increase in interlayer distance of the LDH. X-ray diffraction studies and transmission electron microscope morphological investigations of LDH powders indicated that modification with stearic acid increased the interlayer spacing which would favor the intercalation of NBR polymer chains into the layered space. However, stress-strain studies indicated better mechanical properties for composites with unmodified LDH. Composites with LDH showed higher crosslinking densities than conventionally sulfur cured control compounds using zinc oxide/stearic acid as activators. This was evident from equilibrium swelling method as well as statistical theory of rubber elasticity.

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., Technische Universität Dresden, Rubber Technology Centre, Indian Institute of Technology Kharagpur
Contributors: Eshwaran, S. B., Basu, D., Vaikuntam, S. R., Kutlu, B., Wiessner, S., Das, A., Naskar, K., Heinrich, G.
Publication date: 1 Mar 2015
Peer-reviewed: Yes

Publication information

Journal: Journal of Applied Polymer Science
Volume: 132
Issue number: 9
Article number: 41539
ISSN (Print): 0021-8995
Ratings: 
  • Scopus rating (2015): CiteScore 1.74 SJR 0.587 SNIP 0.846
Original language: English
ASJC Scopus subject areas: Chemistry(all), Surfaces, Coatings and Films, Polymers and Plastics, Materials Chemistry
Keywords: crosslinking, elastomers, mechanical properties, properties and characterization, rubber
Source: Scopus
Source ID: 84913616731

Research output: Contribution to journalArticleScientificpeer-review

Crystallization and sintering of borosilicate bioactive glasses for application in tissue engineering

Typical silicate bioactive glasses are known to crystallize readily during the processing of porous scaffolds. While such crystallization does not fully suppress the bioactivity, the presence of significantly large amounts of crystals leads to a decrease in the rate of reaction of the glass and an uncontrolled release of ions. Furthermore, due to the non-congruent dissolution of silicate glasses, these materials have been shown to remain within the surgical site even 14 years post-operation. Therefore, bioactive materials that can dissolve more effectively and have higher conversion rates are required. Within this work, boron was introduced, in the FDA approved S53P4 glass, at the expense of SiO2. The crystallization and sintering-ability of the newly developed glasses were investigated by differential thermal analysis. All the glasses were found to crystallize primarily from the surface, and the crystal phase precipitation was dependent on the quantity of B2O3 incorporated. The rate of crystallization was found to be lower for the glasses when 25, 50 and 75% of SiO2 was replaced with B2O3. These glasses were further sintered into porous scaffolds using simple heat sintering. The impact of glass particle size and heat treatment temperature on the scaffold porosity and average pore size was investigated. Scaffolds with porosity ranging from 10 to 60% and compressive strength ranging from 1 to 35 MPa were produced. The scaffolds remained amorphous during processing and their ability to rapidly precipitate hydroxycarbonate apatite was maintained. This is of particular interest in the field of tissue engineering as scaffold degradation and reaction is generally faster and offers higher controllability as opposed to the current partially/fully crystallized scaffolds obtained from the FDA approved bioactive glasses.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Photonics Glasses, Faculty of Biomedical Sciences and Engineering, Research group: Computational Biophysics and Imaging Group, Materials Science, Research group: Biomaterials and Tissue Engineering Group, BioMediTech, Department of Mining and Metallurgical Engineering, UMR CNRS 6226 Sciences Chimiques de Rennes, University of Witwatersrand, University of Namibia, Department of Chemistry and Bioengineering
Contributors: Fabert, M., Ojha, N., Erasmus, E., Hannula, M., Hokka, M., Hyttinen, J., Rocherullé, J., Sigalas, I., Massera, J.
Number of pages: 12
Pages: 4514-4525
Publication date: 2017
Peer-reviewed: Yes

Publication information

Journal: Journal of Materials Chemistry B
Volume: 5
Issue number: 23
ISSN (Print): 2050-7518
Ratings: 
  • Scopus rating (2017): CiteScore 4.95 SJR 1.561 SNIP 1.024
Original language: English
ASJC Scopus subject areas: Chemistry(all), Medicine(all), Biomedical Engineering, Materials Science(all)

Bibliographical note

INT=keb,"Fabert, M."

Source: Scopus
Source ID: 85021668458

Research output: Contribution to journalArticleScientificpeer-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 14.23 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
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

Evaluating transparent liquid screen overlay as a haptic conductor: Method of enhancing touchscreen based user interaction by a transparent deformable liquid screen overlay

In line with our previous work, this research focuses on a method for attenuating acoustic components (noise) while providing enhanced vibrotactile feedback signals on mobile devices using, deformable touchscreen overlays. Traditional mechanism of providing tactile feedback to the fingertip via a flat rigid touchscreen is limited due to the dampening of the mechanoreceptors which are sensitive to static deformation and lie at the tips of the intermediate ridges in the epidermal-dermal junction. This tactile mechanism becomes useless when the fingertip acts against a ridged surface (chemically strengthened alkali-aluminosilicate glass). Furthermore, the actuation provided by most devices is indirect with little or no mediation mechanism, which results in filtering various signal frequencies, loss of signal intensity as well as creating acoustic noise. The resulting haptic signal is considerably inefficient and incongruent to the applied signal, which was designed to stimulate user skin contact. To resolve these issues we developed a unique transparent screen overlay conductor which contains an oil based composition (a low viscosity inert nonconductive liquid), that acts as a soft deformable interaction point, enhancing the ratio between tactile signals and the acoustic components, provided by haptic actuators. Using surface mounted and embedded actuators to the overlay, while being attached to an ExoPC Slate, we measured haptic signal to noise correlation, as well as signal efficiency and strength over multiple frequencies and concluded that the haptic conductor was able to limit auditory noise and mediate tactile signals more efficiently than traditional rigid glass based surfaces.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Augmented Human Activities (AHA), Fukoku-Rubber Co.
Contributors: Farooq, A., Evreinov, G., Raisamo, R., Takahata, D.
Publication date: 31 Dec 2015

Host publication information

Title of host publication: 2015 IEEE SENSORS - Proceedings
Publisher: Institute of Electrical and Electronics Engineers Inc.
Article number: 7370186
ISBN (Electronic): 9781479982028
ASJC Scopus subject areas: Instrumentation, Electronic, Optical and Magnetic Materials, Spectroscopy, Electrical and Electronic Engineering
Keywords: haptic signal mediation, haptics user interface, Liquid transparent screen overlay, piezoelectric and voice coil actuators, vibrotactile mechano-transduction
Source: Scopus
Source ID: 84963615224

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

Sulfonated polyetheretherketone/polypropylene polymer blends for the production of photoactive materials

Sulfonated polyetheretherketone (SPEEK) was synthesized via a mono-substitution reaction of PEEK in concentrated sulphuric acid and was blended with polypropylene (PP) in 2-10%w/w concentration to be used for the production of photoactive thermoplastic products. SPEEK and SPEEK/PP blends were characterized using FTIR, DSC, TGA, NMR, rheology, SEM, and EPR. Under UV-Vis irradiation, stable benzophenone ketyl (BPK) radicals were generated by hydrogen extraction from PP. By increasing the amount of SPEEK in the polymer blend a linear increase in the BPK radicals was achieved according to the EPR data. DSC and TGA tests indicated weaknesses in the thermal stability of SPEEK but according to the rheological tests this should not have a major effect on processabililty. The optimal amount of SPEEK in the blend was obtained at 5%w/w. This concentration provided a good compromise between radical concentration, material processability, and cost.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Materials Science
Contributors: Fatarelle, E., Mylläri, V., Ruzzante, M., Pogni, R., Baratto, M. C., Skrifvars, M., Syrjälä, S., Järvelä, P.
Publication date: 1 Feb 2015
Peer-reviewed: Yes

Publication information

Journal: Journal of Applied Polymer Science
Volume: 132
Issue number: 8
Article number: 41509
ISSN (Print): 0021-8995
Ratings: 
  • Scopus rating (2015): CiteScore 1.74 SJR 0.587 SNIP 0.846
Original language: English
ASJC Scopus subject areas: Materials Chemistry, Polymers and Plastics, Surfaces, Coatings and Films, Chemistry(all)
Keywords: Blends, Photochemistry, Polyolefins

Bibliographical note

Article first published online: 1 OCT 2014 ;(Volume 132, Issue 8, February 20, 2015)<br/>Contribution: organisation=mol,FACT1=1<br/>Portfolio EDEND: 2014-12-30<br/>Publisher name: JohnWiley & Sons, Inc.

Source: researchoutputwizard
Source ID: 296

Research output: Contribution to journalArticleScientificpeer-review

Coordination networks incorporating halogen-bond donor sites and azobenzene groups

Two Zn coordination networks, {[Zn(1)(Py)2]2(2-propanol)}n (3) and {[Zn(1)2(Bipy)2](DMF)2}n (4), incorporating halogen-bond (XB) donor sites and azobenzene groups have been synthesized and fully characterized. Obtaining 3 and 4 confirms that it is possible to use a ligand wherein its coordination bond acceptor sites and XB donor sites are on the same molecular scaffold (i.e., an aromatic ring) without interfering with each other. We demonstrate that XBs play a fundamental role in the architectures and properties of the obtained coordination networks. In 3, XBs promote the formation of 2D supramolecular layers, which, by overlapping each other, allow the incorporation of 2-propanol as a guest molecule. In 4, XBs support the connection of the layers and are essential to firmly pin DMF solvent molecules through I⋯O contacts, thus increasing the stability of the solvated systems.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Research group: Supramolecular photochemistry
Contributors: Fernandez-Palacio, F., Saccone, M., Priimägi, A., Terraneo, G., Pilati, T., Metrangolo, P., Resnati, G.
Number of pages: 7
Pages: 2251-2257
Publication date: 7 Apr 2016
Peer-reviewed: Yes

Publication information

Journal: CrystEngComm
Volume: 18
Issue number: 13
ISSN (Print): 1466-8033
Ratings: 
  • Scopus rating (2016): CiteScore 3.37 SJR 1.053 SNIP 0.905
Original language: English
ASJC Scopus subject areas: Chemistry(all), Materials Science(all), Condensed Matter Physics
Source: Scopus
Source ID: 84962331348

Research output: Contribution to journalArticleScientificpeer-review

Bi-directional cell-pericellular matrix interactions direct stem cell fate

Modifiable hydrogels have revealed tremendous insight into how physical characteristics of cells’ 3D environment drive stem cell lineage specification. However, in native tissues, cells do not passively receive signals from their niche. Instead they actively probe and modify their pericellular space to suit their needs, yet the dynamics of cells’ reciprocal interactions with their pericellular environment when encapsulated within hydrogels remains relatively unexplored. Here, we show that human bone marrow stromal cells (hMSC) encapsulated within hyaluronic acid-based hydrogels modify their surroundings by synthesizing, secreting and arranging proteins pericellularly or by degrading the hydrogel. hMSC’s interactions with this local environment have a role in regulating hMSC fate, with a secreted proteinaceous pericellular matrix associated with adipogenesis, and degradation with osteogenesis. Our observations suggest that hMSC participate in a bi-directional interplay between the properties of their 3D milieu and their own secreted pericellular matrix, and that this combination of interactions drives fate.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Biomaterials and Tissue Engineering Group, Faculty of Biomedical Sciences and Engineering, King’s College London, The Francis Crick Institute, UCL Eastman Dental Institute, Imperial College, London, 24.8.2012, University College London, Uppsala University, University of Toronto, Canada
Contributors: Ferreira, S. A., Motwani, M. S., Faull, P. A., Seymour, A. J., Yu, T. T., Enayati, M., Taheem, D. K., Salzlechner, C., Haghighi, T., Kania, E. M., Oommen, O. P., Ahmed, T., Loaiza, S., Parzych, K., Dazzi, F., Varghese, O. P., Festy, F., Grigoriadis, A. E., Auner, H. W., Snijders, A. P., Bozec, L., Gentleman, E.
Number of pages: 12
Publication date: Dec 2018
Peer-reviewed: Yes

Publication information

Journal: Nature Communications
Volume: 9
Issue number: 1
Article number: 4049
ISSN (Print): 2041-1723
Ratings: 
  • Scopus rating (2018): CiteScore 12.19 SJR 5.992 SNIP 2.805
Original language: English
ASJC Scopus subject areas: Chemistry(all), Biochemistry, Genetics and Molecular Biology(all), Physics and Astronomy(all)
Electronic versions: 
Source: Scopus
Source ID: 85054315213

Research output: Contribution to journalArticleScientificpeer-review

Synthesis, characterization and solid-state photoluminescence studies of six alkoxy phenylene ethynylene dinuclear palladium(ii) rods

A rare family of six discrete binuclear [PdCl(PEt3)2] phenylene ethynylene rods with alkoxy side chains (methoxy, ethoxy and heptoxy) have been developed, and their solid-state photoluminescence results have been presented and discussed. The shorter bridging ligands are of the general formula H-CC-C6H2(R)2-CC-H, where R = H, OCH3, OC2H5, and OC7H15, whereas the longer ones are based on H-CC-C6H4-CC-C6H2(R)2-CC-C6H4-CC-H, where R = OCH3, OC2H5. These ligands display increasing length in both the main dimension (backbone length) as well as the number of carbons in the side chains (R, alkoxide side chain) that stem from the central phenylene moiety. The X-ray crystal structures of two of the prepared complexes are reported: one corresponds to a shorter rod, 1,4-bis[trans-(PEt3)2ClPd-CC]-2,5-diethoxybenzene (6c), while the second one is associated with a longer rod, the binuclear complex 1,4-bis[trans-(PEt3)2ClPd-4-(-CC-C6H4-CC)]-2,5-diethoxybenzene (7c). All new compounds were characterized by NMR spectroscopy (1H, 13C{1H} and 31P{1H}) as well as ESI-MS(TOF), EA, FTIR, UV-Vis, cyclic voltammetry and solid-state photoluminescence. Our work shows the influence of the alkoxy side chains on the electronic structure of the family of binuclear Pd rods by lowering its oxidation potential. In addition to this, the increase of the length of the bridge results in a higher oxidation potential. Solid state photoluminescence results indicate that Pd complexes are characterized by a marked decrease in both the emission intensity and the fluorescence lifetime values as compared to their ligands. This behaviour could be due to some degree of ligand-to-metal charge transfer. This journal is

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: University of Jyväskylä, CQM-Centro de Química da Madeira, Universidade da Madeira Campus Universitário da Penteada, MMRG, Departamento de Física Fundamental y Experimental, Faculdad de Física, Universidad de la Laguna
Contributors: Figueira, J., Czardybon, W., Mesquita, J. C., Rodrigues, J., Lahoz, F., Russo, L., Valkonen, A., Rissanen, K.
Number of pages: 13
Pages: 4003-4015
Publication date: 7 Mar 2015
Peer-reviewed: Yes

Publication information

Journal: DALTON TRANSACTIONS
Volume: 44
Issue number: 9
ISSN (Print): 1477-9226
Ratings: 
  • Scopus rating (2015): CiteScore 4.1 SJR 1.302 SNIP 1.001
Original language: English
ASJC Scopus subject areas: Inorganic Chemistry
Source: Scopus
Source ID: 84923350178

Research output: Contribution to journalArticleScientificpeer-review

Measuring synthesis yield in graphene oxide synthesis by modified hummers method

Synthesis of graphene oxide by the modified Hummers method and measuring the synthesis yield were investigated. Based on the results, a comprehensive method to measure graphene oxide synthesis yield was proposed, which will allow comparison of future literature results. In addition, changes are proposed to the exfoliation procedure to improve the yield of the modified Hummers synthesis. With the proposed method, systematic error of the concentration measurement was calculated to be ±0.08 × 10<sup>-3</sup> g mL<sup>-1</sup>. In addition, changes proposed to the graphene oxide exfoliation process can improve the synthesis yield by up to 70%.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Materials Science, Research group: Ceramic materials, Tampere University of Technology, Department of Chemistry and Bioengineering, Research group: Supramolecular photochemistry, Research group: Materials Characterization, Engineering materials science and solutions (EMASS), University of Helsinki
Contributors: Frankberg, E. J., George, L., Efimov, A., Honkanen, M., Pessi, J., Levänen, E.
Number of pages: 5
Pages: 755-759
Publication date: 2 Sep 2015
Peer-reviewed: Yes

Publication information

Journal: Fullerenes Nanotubes and Carbon Nanostructures
Volume: 23
Issue number: 9
ISSN (Print): 1536-383X
Ratings: 
  • Scopus rating (2015): CiteScore 1.62 SJR 0.278 SNIP 0.596
Original language: English
ASJC Scopus subject areas: Organic Chemistry, Physical and Theoretical Chemistry, Materials Science(all), Atomic and Molecular Physics, and Optics
Keywords: Concentration, Graphene oxide, Hummers method, Synthesis, Yield
Electronic versions: 

Bibliographical note

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Source: Scopus
Source ID: 84929598253

Research output: Contribution to journalArticleScientificpeer-review

The Suzuki, the Heck, and the Stille reaction - Three versatile methods, for the introduction of new C-C bonds on solid support

Metal-catalyzed coupling reactions are very efficient and reliable methods for the introduction of new carbon-carbon bonds onto molecules attached to a solid support. This review summarizes recent advances in utilizing the three most used methods, the Suzuki reaction, the Heck reaction, and the Stille reaction, in the field of solid phase organic synthesis resulting in small organic molecule libraries.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: University of Helsinki
Contributors: Franzén, R.
Number of pages: 6
Pages: 957-962
Publication date: 2000
Peer-reviewed: Yes

Publication information

Journal: Canadian Journal of Chemistry - Revue Canadienne de Chimie
Volume: 78
Issue number: 7
ISSN (Print): 0008-4042
Ratings: 
  • Scopus rating (2000): SJR 0.628 SNIP 0.672
Original language: English
ASJC Scopus subject areas: Chemistry(all)
Keywords: Carbon-carbon bonds, Combinatorial chemistry, Drug discovery, Metal-catalyzed coupling reactions, Solid phase synthesis
Source: Scopus
Source ID: 0033843143

Research output: Contribution to journalArticleScientificpeer-review

Recent advances in the preparation of heterocycles on solid support: A review of the literature

General information

Publication status: Published
MoE publication type: A2 Review article in a scientific journal
Organisations: University of Helsinki
Contributors: Franzén, R. G.
Number of pages: 20
Pages: 195-214
Publication date: May 2000
Peer-reviewed: Yes

Publication information

Journal: Journal of Combinatorial Chemistry
Volume: 2
Issue number: 3
ISSN (Print): 1520-4766
Original language: English
ASJC Scopus subject areas: Chemistry(all), Organic Chemistry, Discrete Mathematics and Combinatorics, Drug Discovery
Source: Scopus
Source ID: 0041037814

Research output: Contribution to journalReview ArticleScientificpeer-review

Utilization of Grignard reagents in solid-phase synthesis: A review of the literature

General information

Publication status: Published
MoE publication type: A2 Review article in a scientific journal
Organisations: University of Helsinki
Contributors: Franzén, R. G.
Number of pages: 7
Pages: 685-691
Publication date: 28 Jan 2000
Peer-reviewed: Yes

Publication information

Journal: Tetrahedron
Volume: 56
Issue number: 5
ISSN (Print): 0040-4020
Ratings: 
  • Scopus rating (2000): SJR 1.536 SNIP 1.113
Original language: English
ASJC Scopus subject areas: Biochemistry, Organic Chemistry, Drug Discovery
Source: Scopus
Source ID: 0034723167

Research output: Contribution to journalReview ArticleScientificpeer-review

Investigation of the adducts formed by reaction of butenedioic acids with adenosine

Several genotoxic butenedioic acids present in chlorine-disinfected drinking water were allowed to react with adenosine, guanosine, and cytidine in aqueous solution. HPLC analyses, with detection at 254 and 310 nm, showed that clearly detectable products were formed only in the reactions with adenosine. The major products from the reactions between either 2-chloro-3- methyl-2-butenedioic acid (ox-MCF) or 2-chloro-3-(chloromethyl)-2- butenedioic acid (ox-CMCF) and adenosine were the same. This substance was isolated by C18 column chromatography and characterized by UV absorbance, 1H and 13C NMR spectroscopy, and mass spectrometry. It was identified as 3-(β-D-ribofuranosyl)-7-carboxy-7-formyl-8-[9'-(β-D-ribofuranosyl)-N 6- adenosinyl]-1,N 6-ethanoadenosine (cfεA,A). The yields of cfεA,A in reactions performed at pH 7.4 and 37 °C were 0.7% and 0.3% with ox-MCF and ox-CMCF, respectively.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Natl. Inst. for Environ. Studies
Contributors: Franzén, R., Morita, M., Tanabe, K., Takagi, H., Shibata, Y.
Number of pages: 6
Pages: 1186-1191
Publication date: Oct 1997
Peer-reviewed: Yes

Publication information

Journal: Chemical Research in Toxicology
Volume: 10
Issue number: 10
ISSN (Print): 0893-228X
Original language: English
ASJC Scopus subject areas: Drug Discovery, Organic Chemistry, Chemistry(all), Toxicology, Health, Toxicology and Mutagenesis
Source: Scopus
Source ID: 0030778905

Research output: Contribution to journalArticleScientificpeer-review

Synthesis of chlorinated 5-hydroxy 4-methyl-2(5H)-furanones and mucochloric acid

An improved procedure for the synthesis of chlorinated 5-hydroxy-4-methyl-2(5H)-furanones is described. By this method also carbon-labelled (13C and 14C at C-3) hydroxyfuranones, including mucochioric acid, can be prepared. Each step of the method was examined in an effort to optimize both the yield and the purity of the compounds.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Abo Akademi University
Contributors: Franzén, R., Kronberg, L.
Number of pages: 4
Pages: 3905-3908
Publication date: 29 May 1995
Peer-reviewed: Yes

Publication information

Journal: Tetrahedron Letters
Volume: 36
Issue number: 22
ISSN (Print): 0040-4039
Original language: English
ASJC Scopus subject areas: Biochemistry, Organic Chemistry, Drug Discovery
Source: Scopus
Source ID: 0029012567

Research output: Contribution to journalArticleScientificpeer-review

La thérapie photodynamique: État de l'art et perspectives

Photodynamic therapy (PDT) is a method of medical treatment using the concomitant action of a photoactivatable molecule called the photosensitizer (PS), light, and oxygen naturally present in the biological medium. After light excitation of the photosensitizer, an energy transfer to oxygen allows to generate the formation of reactive oxygen species, especially singlet oxygen reactive leading to cell death. This technique proves to be very efficient for certain types of cancer (especially in dermatology) and is promising in other pathologies (prostate, brain). This article briefly describes the principle of PDT and then analyzes the latest advances in PDT in terms of clinical applications (actinic keratoses, prostate, brain cancer, retinoblastoma) and the use of PDT for antibacterial applications. Finally, the prospects of this technique with among others the development of new vesicles or the use of X-rays as a source of energy to overcome the problems of light penetration in tissues are presented.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Frontier Photonics, Université de Lorraine, ISLM, Universite' Pierre et Marie Curie, Sorbonne, France, 13.12.2011, Université de Montpellier 2, Université Reims Champagne Ardenne, Univ Paris 06, Centre National de la Recherche Scientifique (CNRS), Pierre & Marie Curie University - Paris 6, Institut de Recherche pour le Developpement (IRD), Inria, Institut National de la Sante et de la Recherche Medicale (Inserm), Univ Sorbonne, CNRS,ICM,UMR S 1127,UMR 7225,U1127, INSERM,Inria Paris Rocquencourt,Inst Cerveau & Mo, Institut Curie, Groupement de Recherche Eau Sol Environnement, Université Paul Sabatier
Contributors: Frochot, C., Barberi-Heyob, M., Blanchard-Desce, M., Bolotine, L., Bonneau, S., Jimenez, C. M., Durand, J. O., Lassalle, H. P., Lemercier, G., Mordon, S., Maillard, P., Sol, V., Vever-Bizet, C., Vicendo, P.
Number of pages: 5
Pages: 46-50
Publication date: 1 Jun 2015
Peer-reviewed: Yes

Publication information

Journal: ACTUALITE CHIMIQUE
Issue number: 397-398
ISSN (Print): 0151-9093
Ratings: 
  • Scopus rating (2015): CiteScore 0.04 SJR 0.102 SNIP 0.003
Original language: French
ASJC Scopus subject areas: Chemistry(all)
Keywords: Cancer, Photodynamic therapy, Photosensitizer
Source: Scopus
Source ID: 84973500613

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 1.44 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

Buckling Behavior of Cold-Formed Studs with Thermal Perforations

Studies have shown that the optimal structural scheme for low-rise buildings that meets all regulatory requirements is a frame system. In this connection, thin-walled cold-formed steel (CFS) profiles seem to be the best material for constructing light steel framed (LSF) walls. The framework of LSF walls is usually constructed from CFS C-shaped profiles. To increase the thermal effectiveness of a wall, CFS profiles usually have thermal perforations and thus are called thermoprofiles. However, these openings have a negative impact on bearing capacity of profiles and require accurate evaluation. In this article a relatively new reticular-stretched thermoprofile with diamond-shaped openings is considered. The article deals with the buckling analysis of perforated CFS C-sections subjected to compression.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Peter the Great Saint-Petersburg Polytechnic University, University of Maribor
Contributors: Garifullin, M., Sinelnikov, A., Bronzova, M., Kovacic, B., Kamnik, R.
Publication date: 11 Aug 2016
Peer-reviewed: Yes

Publication information

Journal: MATEC Web of Conferences
Volume: 73
Article number: 04011
ISSN (Print): 2274-7214
Ratings: 
  • Scopus rating (2016): CiteScore 0.2 SJR 0.132 SNIP 0.346
Original language: English
ASJC Scopus subject areas: Chemistry(all), Engineering(all), Materials Science(all)
Source: Scopus
Source ID: 84983508952

Research output: Contribution to journalArticleScientificpeer-review

Experimental moment resistance of rectangular hollow section T joints

Resistance is the main property of tubular joints. The determination of the joint resistance from the experimental load-deformation curve always represents a challenging task. Currently there are two main methods to find the experimental resistance, which are called plastic and ultimate resistance. However, there is no single opinion on which one should be commonly used. Based on the experimental results, this paper directly compares the two existed approaches. The study is restricted to welded square hollow section T joints under in-plane bending moment. The paper considers only the joints with β < 0.85, i.e. when the behaviour of the joint is governed by chord face failure. The results show that plastic resistance leads to more conservative results than ultimate resistance, providing thus safer results. However, attention should be also paid to the difference between the labour intensity of the presented methods.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Civil Engineering
Contributors: Garifullin, M.
Publication date: 5 Dec 2018
Peer-reviewed: Yes

Publication information

Journal: MATEC Web of Conferences
Volume: 245
Article number: 08003
ISSN (Print): 2274-7214
Ratings: 
  • Scopus rating (2018): CiteScore 0.42 SJR 0.169 SNIP 0.548
Original language: English
ASJC Scopus subject areas: Chemistry(all), Materials Science(all), Engineering(all)
Electronic versions: 
Source: Scopus
Source ID: 85058463414

Research output: Contribution to journalConference articleScientificpeer-review

Human adipose stem cells in chondrogenic differentiation medium without growth factors differentiate towards annulus fibrosus phenotype in vitro

Summary Intervertebral disc degeneration is the main cause of chronic back pain. Disc degeneration mainly leads to tearing of annulus fibrosus (AF), which is with current methods difficult to restore and impossible to regenerate. Stem cell technology offers a potential technique to repair the ruptured AF by enabling new matrix synthesis at the defect site. Previous studies have shown that human adipose stem cells (hASCs) are able to differentiate towards AF phenotype when treated with suitable growth factors. There are concerns about the use of growth factors in clinical applications because of their short half-lives, high costs and low effectiveness. The main aim of this research project was to regenerate AF tissue in vitro using hASCs and serum free chondrogenic medium without supplementation of growth factors. Differentiation of hASCs was induced by using the micromass culture technique. Human annulus fibrosus cell (hAFCs) cultured in commercial AF growth medium were used as positive control. Assessment of AF phenotype of hASCs and hAFCs was done at 14 and 21 days of culture. Quantification of sulphated glycosaminoglycan (GAG) content showed that hASCs cultured in chondrogenic medium expressed similar levels of sulphated GAGs as hAFCs. qRT-PCR confirmed the similarity of the differentiated hASCs with AF phenotype. Several markers for AF phenotype (aggrecan, collagen type I and glypican-3) were expressed in both hAFCs and differentiated hASCs. This is the first study that demonstrated that hASCs can be differentiated towards AF phenotype using serum free chondrogenic medium without growth factors. In a next step, scaffolds manufactured from biodegradable polymers will be used in combination with ASCs to find an optimal construct to repair AF defects.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Integrated Technologies for Tissue Engineering Research (ITTE), University of Twente, University of Groningen
Contributors: Gebraad, A. W. H., Miettinen, S., Grijpma, D. W., Haimi, S. P.
Number of pages: 8
Pages: 49-56
Publication date: Dec 2013
Peer-reviewed: Yes

Publication information

Journal: Macromolecular symposia
Volume: 334
Issue number: 1
ISSN (Print): 1022-1360
Ratings: 
  • Scopus rating (2013): CiteScore 0.71 SJR 0.326 SNIP 0.388
Original language: English
ASJC Scopus subject areas: Organic Chemistry, Materials Chemistry, Polymers and Plastics, Condensed Matter Physics
Keywords: adipose stem cells, annulus fibrosus, intervertebral disc, tissue engineering
Source: Scopus
Source ID: 84890722713

Research output: Contribution to journalArticleScientificpeer-review

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

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

General information

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

Publication information

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

Research output: Contribution to journalArticleScientificpeer-review

Cell toxicity and oxidative potential of engine exhaust particles: Impact of using particulate filter or biodiesel fuel blend

The link between emissions of vehicular particulate matter (PM) and adverse health effects is well established. However, the influence of new emission control technologies and fuel types on both PM emissions and health effects has been less well investigated. We examined the health impact of PM emissions from two vehicles equipped with or without a diesel particulate filter (DPF). Both vehicles were powered either with diesel (B0) or a 50% v/v biodiesel blend (B50). The DPF effectively decreased PM mass emissions (∼85%), whereas the fuel B50 without DPF lead to less reduction (∼50%). The hazard of PM per unit distance driven was decreased for the DPF-equipped vehicle as indicated by a reduced cytotoxicity, oxidative, and pro-inflammatory potential. This was not evident and even led to an increase when the hazard was expressed on a per unit of mass basis. In general, the PM oxidative potential was similar or reduced for the B50 compared to the B0 powered vehicle. However, the use of B50 resulted in increased cytotoxicity and IL-6 release in BEAS-2B cells irrespective of the expression metric. This study shows that PM mass reduction achieved by the use of B50 will not necessarily decrease the hazard of engine emissions, while the application of a DPF has a beneficial effect on both PM mass emission and PM hazard.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Urban circular bioeconomy (UrCirBio), National Institute for Public Health and the Environment, Norwegian Institute of Public Health, Aristotle University of Thessaloniki, Laboratory of Applied Thermodynamics, Utrecht University
Contributors: Gerlofs-Nijland, M. E., Totlandsdal, A. I., Tzamkiozis, T., Leseman, D. L. A. C., Samaras, Z., Låg, M., Schwarze, P., Ntziachristos, L., Cassee, F. R.
Number of pages: 8
Pages: 5931-5938
Publication date: 4 Jun 2013
Peer-reviewed: Yes

Publication information

Journal: Environmental Science and Technology
Volume: 47
Issue number: 11
ISSN (Print): 0013-936X
Ratings: 
  • Scopus rating (2013): CiteScore 5.52 SJR 2.952 SNIP 2.094
Original language: English
ASJC Scopus subject areas: Chemistry(all), Environmental Chemistry
Source: Scopus
Source ID: 84878655379

Research output: Contribution to journalArticleScientificpeer-review

Proliferation and differentiation of adipose stem cells towards smooth muscle cells on poly(trimethylene carbonate) membranes

Summary Multipotent human adipose stem cells (hASCs) are an abundant and potential source of cells for vascular tissue engineering when combined with a suitable biomaterial scaffold. Poly(trimethylene carbonate) (PTMC) has been shown to be a useful biodegradable material for tissue engineered vascular grafts due to its flexibility, excellent biocompatibility and enzymatic degradation by surface erosion in vivo. The purpose of the current study was to evaluate the proliferation and differentiation of hASCs towards smooth muscle cells (SMCs) on gamma-crosslinked and photo-crosslinked PTMC membranes. PTMC macromers were functionalized with methacrylate end groups and crosslinked by UV initiated radical polymerization. High molecular weight linear PTMC was crosslinked by gamma irradiation. Cell viability, cell numbers and SMC differentiation of hASCs were evaluated on the differently crosslinked PTMC films at 7 and 14 days (d). On the photo-crosslinked membranes, homogenous monolayers of hASC were detected by live/dead assay. Consistently, cells on the photo-crosslinked membranes had significantly higher cell numbers compared to cells on the gamma-crosslinked membranes after 14 d of culture. SMC specific genes were expressed on both membranes at 14 d. Photo-crosslinked membranes showed higher expression of SMC specific proteins at 14 d compared to gamma-crosslinked membranes. These results suggest that especially the photo-crosslinked PTMC membranes are suitable for vascular tissue engineering applications when combined with hASCs.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Integrated Technologies for Tissue Engineering Research (ITTE), Aachen University of Applied Sciences, University of Groningen
Contributors: German, S. J., Behbahani, M., Miettinen, S., Grijpma, D. W., Haimi, S. P.
Number of pages: 10
Pages: 133-142
Publication date: Dec 2013
Peer-reviewed: Yes

Publication information

Journal: Macromolecular symposia
Volume: 334
Issue number: 1
ISSN (Print): 1022-1360
Ratings: 
  • Scopus rating (2013): CiteScore 0.71 SJR 0.326 SNIP 0.388
Original language: English
ASJC Scopus subject areas: Condensed Matter Physics, Polymers and Plastics, Organic Chemistry, Materials Chemistry
Keywords: adipose stem cell differentiation, poly (trimethylene carbonate), smooth muscle cells, tissue engineering
Source: Scopus
Source ID: 84890729494

Research output: Contribution to journalArticleScientificpeer-review

Pyrolytic behavior of lignocellulosic-based polysaccharides

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

General information

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

Publication information

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

Research output: Contribution to journalArticleScientificpeer-review

The Hosoya entropy of graphs revisited

In this paper we extend earlier results on Hosoya entropy (H-entropy) of graphs, and establish connections between H-entropy and automorphisms of graphs. In particular, we determine the H-entropy of graphs whose automorphism group has exactly two orbits, and characterize some classes of graphs with zero H-entropy.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Computational Medicine and Statistical Learning Laboratory (CMSL), Computing Sciences, Research group: Predictive Society and Data Analytics (PSDA), Shahid Rajaee Teacher Training University, University of Applied Sciences Upper Austria, School of Management, Hall in Tyrol, Nankai University, The City College of New York (CUNY), Aalto University, Peking University
Contributors: Ghorbani, M., Dehmer, M., Mowshowitz, A., Tao, J., Emmert-Streib, F.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Symmetry
Volume: 11
Issue number: 8
Article number: 1013
ISSN (Print): 2073-8994
Original language: English
ASJC Scopus subject areas: Computer Science (miscellaneous), Chemistry (miscellaneous), Mathematics(all), Physics and Astronomy (miscellaneous)
Keywords: Automorphism of graphs, Graph entropy, Graph products
Electronic versions: 
Source: Scopus
Source ID: 85070525428

Research output: Contribution to journalArticleScientificpeer-review

Non-universal tracer diffusion in crowded media of non-inert obstacles

We study the diffusion of a tracer particle, which moves in continuum space between a lattice of excluded volume, immobile non-inert obstacles. In particular, we analyse how the strength of the tracer-obstacle interactions and the volume occupancy of the crowders alter the diffusive motion of the tracer. From the details of partitioning of the tracer diffusion modes between trapping states when bound to obstacles and bulk diffusion, we examine the degree of localisation of the tracer in the lattice of crowders. We study the properties of the tracer diffusion in terms of the ensemble and time averaged mean squared displacements, the trapping time distributions, the amplitude variation of the time averaged mean squared displacements, and the non-Gaussianity parameter of the diffusing tracer. We conclude that tracer-obstacle adsorption and binding triggers a transient anomalous diffusion. From a very narrow spread of recorded individual time averaged trajectories we exclude continuous type random walk processes as the underlying physical model of the tracer diffusion in our system. For moderate tracer-crowder attraction the motion is found to be fully ergodic, while at stronger attraction strength a transient disparity between ensemble and time averaged mean squared displacements occurs. We also put our results into perspective with findings from experimental single-particle tracking and simulations of the diffusion of tagged tracers in dense crowded suspensions. Our results have implications for the diffusion, transport, and spreading of chemical components in highly crowded environments inside living cells and other structured liquids.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Physics, Institute for Physics and Astronomy, University of Potsdam
Contributors: Ghosh, S. K., Cherstvy, A. G., Metzler, R.
Number of pages: 12
Pages: 1847-1858
Publication date: 21 Jan 2015
Peer-reviewed: Yes

Publication information

Journal: Physical Chemistry Chemical Physics
Volume: 17
Issue number: 3
ISSN (Print): 1463-9076
Ratings: 
  • Scopus rating (2015): CiteScore 4.45 SJR 1.725 SNIP 1.188
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Physics and Astronomy(all)
Source: Scopus
Source ID: 84919346836

Research output: Contribution to journalArticleScientificpeer-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 5.96 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
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all)
Source: Scopus
Source ID: 80051876637

Research output: Contribution to journalArticleScientificpeer-review

An electro-optically tunable Bragg reflector based on liquid crystals

In this paper we report the analysis of a distributed feedback guided-wave reflector in liquid crystals and we describe the main properties of the device. The device is based on a comb-shaped interdigitated electrodes and a liquid crystal slab. The device shows a wide tuning range exceeding 100 nm covering C and L bands for wavelength division multiplexing.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Frontier Photonics, Sapienza University, University “Roma Tre”, Dipartimento di Ingegneria dell'Informazione, Elettronica e Telecomunicazioni
Contributors: Gilardi, G., Asquini, R., D'Alessandro, A., Assanto, G.
Number of pages: 7
Pages: 62-68
Publication date: 2011
Peer-reviewed: Yes

Publication information

Journal: Molecular Crystals and Liquid Crystals
Volume: 549
ISSN (Print): 1542-1406
Ratings: 
  • Scopus rating (2011): CiteScore 0.53 SJR 0.288 SNIP 0.473
Original language: English
ASJC Scopus subject areas: Chemistry(all), Condensed Matter Physics, Materials Science(all)
Keywords: electro-optic effect, liquid crystals, Optical waveguides
Source: Scopus
Source ID: 80053362957

Research output: Contribution to journalArticleScientificpeer-review

Energy-dependent diffusion in a soft periodic Lorentz gas

The periodic Lorentz gas is a paradigmatic model to examine how macroscopic transport emerges from microscopic chaos. It consists of a triangular lattice of circular hard scatterers with a moving point particle. Recently this system became relevant as a model for electronic transport in low-dimensional nanosystems such as molecular graphene. However, to more realistically mimic such dynamics, the hard Lorentz gas scatterers should be replaced by soft potentials. Here we study diffusion in a soft Lorentz gas with Fermi potentials under variation of the total energy of the moving particle. Our goal is to understand the diffusion coefficient as a function of the energy. In our numerical simulations we identify three different dynamical regimes: (i) the onset of diffusion at small energies; (ii) a transition where for the first time a particle reaches the top of the potential, characterized by the diffusion coefficient abruptly dropping to zero; and (iii) diffusion at high energies, where the diffusion coefficient increases according to a power law in the energy. All these different regimes are understood analytically in terms of simple random walk approximations.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research area: Computational Physics, Research group: Quantum Control and Dynamics, Physics, School of Mathematical Sciences, Technische Universität Berlin, Universitat zu Koln, Computational Physics Laboratory
Contributors: Gil-Gallegos, S., Klages, R., Solanpää, J., Räsänen, E.
Number of pages: 18
Pages: 143-160
Publication date: 1 May 2019
Peer-reviewed: Yes

Publication information

Journal: European Physical Journal: Special Topics
Volume: 228
Issue number: 1
ISSN (Print): 1951-6355
Original language: English
ASJC Scopus subject areas: Materials Science(all), Physics and Astronomy(all), Physical and Theoretical Chemistry
Source: Scopus
Source ID: 85066258822

Research output: Contribution to journalArticleScientificpeer-review

Arrhenius analysis of anisotropic surface self-diffusion on the prismatic facet of ice

We present an Arrhenius analysis of self-diffusion on the prismatic surface of ice calculated from molecular dynamics simulations. The six-site water model of Nada and van der Eerden was used in combination with a structure-based criterion for determining the number of liquid-like molecules in the quasi-liquid layer. Simulated temperatures range from 230 K-287 K, the latter being just below the melting temperature of the model, 289 K. Calculated surface diffusion coefficients agree with available experimental data to within quoted precision. Our results indicate a positive Arrhenius curvature, implying a change in the mechanism of self-diffusion from low to high temperature, with a concomitant increase in energy of activation from 29.1 kJ mol -1 at low temperature to 53.8 kJ mol -1 close to the melting point. In addition, we find that the surface self-diffusion is anisotropic at lower temperatures, transitioning to isotropic in the temperature range of 240-250 K. We also present a framework for self-diffusion in the quasi-liquid layer on ice that aims to explain these observations.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Computational Science X (CompX), Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, University of Puget Sound
Contributors: Gladich, I., Pfalzgraff, W., Maršálek, O., Jungwirth, P., Roeselová, M., Neshyba, S.
Number of pages: 10
Pages: 19960-19969
Publication date: 28 Nov 2011
Peer-reviewed: Yes

Publication information

Journal: Physical Chemistry Chemical Physics
Volume: 13
Issue number: 44
ISSN (Print): 1463-9076
Ratings: 
  • Scopus rating (2011): CiteScore 3.6 SJR 1.707 SNIP 1.184
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Physics and Astronomy(all)
Source: Scopus
Source ID: 80455123676

Research output: Contribution to journalArticleScientificpeer-review

Silver sulfide nanoclusters and the superatom model

The superatom model of electron-shell closings has been widely used to explain the stability of noble-metal nanoclusters of few nanometers, including thiolate-protected Au and Ag nanoclusters. The presence of core sulfur atoms in silver sulfide (Ag-S) nanoclusters renders them a class of clusters with distinctive properties as compared to typical noble-metal clusters. Here, it is natural to ask whether the superatom model is still applicable for the Ag-S nanoclusters with mixed metal and nonmetal core atoms. To address this question, we applied density functional simulations to analyze a series of Ag-S nanoclusters: Ag14S(SPh)12(PPh3)8, Ag14(SC6H3F2)12(PPh3)8, Ag70S16(SPh)34(PhCO2)4(triphos)4, and [Ag123S35(StBu)50]3+. We observed that superatomic orbitals are still present in the conduction band of these Ag-S clusters where the cluster cores comprise mostly silver atoms. Our Bader charge analysis illustrates that thiolates play a significant role in withdrawing charge (electron density) from the core Ag atoms. The simulated optical absorption properties of the selected Ag-S clusters reflect the substantial band gaps associated with typical molecular orbitals on both sides. Apart from Ag14S(SPh)12(PPh3)8, which has a central sulfur atom in the cluster core, superatomic orbitals of the Ag-S clusters can have contributions for individual transitions in the conduction band.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Physics, Research group: Materials and Molecular Modeling, Computational Science X (CompX), University of Jyväskylä, Departments of Physics and Chemistry
Contributors: Goh, J., Malola, S., Häkkinen, H., Akola, J.
Number of pages: 8
Pages: 1583-1590
Publication date: 22 Jan 2015
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry C
Volume: 119
Issue number: 3
ISSN (Print): 1932-7447
Ratings: 
  • Scopus rating (2015): CiteScore 4.68 SJR 1.886 SNIP 1.24
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Electronic, Optical and Magnetic Materials, Surfaces, Coatings and Films, Energy(all)
Source: Scopus
Source ID: 84921476515

Research output: Contribution to journalArticleScientificpeer-review

Superatom Model for Ag-S Nanocluster with Delocalized Electrons

Several Ag–S nanoclusters where the cluster core comprises mixed metal (main component) and sulfur atoms show superatomic orbitals in the conduction band edge. However, there are no superatomic states, i.e., delocalized electrons, in the valence band, and the clusters in question can be labeled as “zerovalent”. We show here an example of an Ag–S cluster which fulfills the superatom model and has delocalized electrons: The recently synthesized and characterized [Ag62S12(StBu)32]2+ cluster has four delocalized valence electrons based on a simple counting rule, and we compare it to the zerovalent cluster [Ag62S13(StBu)32]4+. Our electronic structure analysis confirms the existence of superatomic states in the valence and conduction bands, but the locations of these states do not agree completely with the conventional prediction based on the spherical Jellium model. [Ag62S12(StBu)32]2+ displays the 1S2 electronic shell closure at the Fermi energy instead of the 1S21P2 configuration as suggested by its electron count. This shift of energy levels and electron shell closing has been introduced by the core–shell structure of the cluster. Our optical absorption simulation can reproduce the features observed in the experiments, and we assign these features to the transitions involving superatomic states within the conduction band.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Physics, Research group: Materials and Molecular Modeling, Computational Science X (CompX), COMP Centre of Excellence, Department of Applied Physics, Aalto University
Contributors: Goh, J. Q., Akola, J.
Number of pages: 8
Pages: 21165-21172
Publication date: 10 Sep 2015
Peer-reviewed: Yes
Early online date: 19 Aug 2015

Publication information

Journal: Journal of Physical Chemistry C
Volume: 119
Issue number: 36
ISSN (Print): 1932-7447
Ratings: 
  • Scopus rating (2015): CiteScore 4.68 SJR 1.886 SNIP 1.24
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Electronic, Optical and Magnetic Materials, Surfaces, Coatings and Films, Energy(all)
Source: Scopus
Source ID: 84941254956

Research output: Contribution to journalArticleScientificpeer-review

Geometric Structure and Chemical Ordering of Large AuCu Clusters: A Computational Study

Understanding the structure and composition of nanosized gold-copper (AuCu) clusters is crucial for designing an effective AuCu catalyst. Global optimization of AuCu clusters using atomistic force fields is a viable solution for clusters with at least a few nm sizes, because of its fast computation. Here we develop an atomistic many-body potential for AuCu on the basis of the second-moment approximation to the tight-binding model. We show that our potential is in good agreement with density-functional theory calculations, and use it to study the structure and chemical ordering of clusters of sizes up to ∼4 nm by means of global optimization searches. We show that the clusters present a surface enrichment in Au, while subsurface and central sites are enriched in Cu. Surface enrichment in Au and center enrichment in Cu are stronger in icosahedra. Surface Cu atoms prefer terrace sites on (111) facets. Both atomistic and DFT calculations show that L10 and L12 ordered phases are not favorable, even at their ideal compositions for these sizes, because of the tendency of Au to surface segregation. The stability range of icosahedral structures is wider in AuCu nanoalloys than in Au and Cu pure clusters.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, COMP Centre of Excellence, Department of Applied Physics, Aalto University, Aalto University, Università di Genova
Contributors: Goh, J., Akola, J., Ferrando, R.
Number of pages: 8
Pages: 10809-10816
Publication date: 25 May 2017
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry C
Volume: 121
Issue number: 20
ISSN (Print): 1932-7447
Ratings: 
  • Scopus rating (2017): CiteScore 4.58 SJR 2.135 SNIP 1.135
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Energy(all), Physical and Theoretical Chemistry, Surfaces, Coatings and Films
Source: Scopus
Source ID: 85016919329

Research output: Contribution to journalArticleScientificpeer-review

Thermal desorption of molecular oxygen from SnO2 (110) surface: Insights from first-principles calculations

First-principles density functional theory calculations in the generalized gradient approximation, with plane wave basis set and pseudopotentials, have been used to investigate the desorption pathways of molecular oxygen species adsorbed on the SnO2 (110) surface. Energetics of the thermodynamically favored precursors is studied in dependence on the surface charge provided either by surface defects or by donor type impurities from the near-surface region. The resonant desorption modes of O2 molecules are examined in the framework of ab initio atomic thermodynamics and relationship of these results to experimental observations is discussed.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Physics, Research area: Computational Physics, Research group: Electronic Structure Theory, South-Ukrainian University
Contributors: Golovanov, V., Golovanova, V., Rantala, T. T.
Number of pages: 8
Pages: 15-22
Publication date: 2016
Peer-reviewed: Yes

Publication information

Journal: Journal of Physics and Chemistry of Solids
Volume: 89
ISSN (Print): 0022-3697
Ratings: 
  • Scopus rating (2016): CiteScore 1.94 SJR 0.596 SNIP 0.948
Original language: English
ASJC Scopus subject areas: Condensed Matter Physics, Chemistry(all), Materials Science(all)
Keywords: A. oxides, B. ab initio calculations, C. surface properties
Source: Scopus
Source ID: 84945973267

Research output: Contribution to journalArticleScientificpeer-review

Effects of orientation at the phthalocyanine-CdSe interface on the electron transfer characteristics

A phthalocyanine molecule adsorbed on the (1010) surface of wurtzite CdSe is theoretically modeled by the DFT method. We have found that a linker does not affect substantially the redox properties of phthalocyanine, while saturation of the macrocycle with peripheral substituent groups causes a downward shift in the energy position of its frontier orbitals that can hinder electron injection to the CdSe surface. Tilting of the phthalocyanine molecule relative to the surface also leads to the lowering of its molecular electronic levels relative to the bands of CdSe. At a tilting angle of 30°, the LUMO level of the dye appears to be lower than the conduction band minimum of cadmium selenide, which makes the electron transfer to its hybridized surface unfavorable. By contrast, the HOMO level of the phenylbutyric acid linker provides a suitable intermediate channel for the hole transfer from the valence band of CdSe to the phthalocyanine that points to the possible acceptor behavior of the phthalocyanine molecule in its hybrids with CdSe nanostructures.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Research group: Electronic Structure Theory, Research area: Computational Physics, Center of Innovation Technologies
Contributors: Golovanov, V. V., Nazarchuk, B. V., Golovanova, V. V., Tkachenko, N. V., Rantala, T. T.
Number of pages: 7
Pages: 10511-10517
Publication date: 2017
Peer-reviewed: Yes

Publication information

Journal: Physical Chemistry Chemical Physics
Volume: 19
Issue number: 16
ISSN (Print): 1463-9076
Ratings: 
  • Scopus rating (2017): CiteScore 4.04 SJR 1.686 SNIP 1.075
Original language: English
ASJC Scopus subject areas: Physics and Astronomy(all), Physical and Theoretical Chemistry
Source: Scopus
Source ID: 85019969347

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 14.23 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

Effect of head group size on the photoswitching applications of azobenzene Disperse Red 1 analogues

We investigate the effect of the increased molecular bulk in the 'head' group for a class of newly synthesized azobenzene chromophores with a clickable ethynyl group para and a nitro group ortho to the azo bond on the distal benzene ring. This 'variable-head' functionalization provides a family of dyes with photophysical characteristics very similar to those of Disperse Red 1, one of the most commonly used azo dyes in materials science. Phenyl, naphthyl, and anthracyl derivatives were synthesized as small molecules, monomers, homopolymers, and copolymers in a rapid and facile manner using click chemistry, confirming the versatility of this parent chromophore. Photochemical and spectral studies indicate that this strategy is suitable to build a 'bulkiness series' of stimuli-responsive materials, as the various material derivatives retain the absorption and kinetic characteristics of the parent chromophore necessary for all optical patterning applications that DR1 dyes have been optimized for. In thin films, larger head group size was found to increase the stability of light-induced birefringence in copolymers. The homopolymers formed stable surface-relief gratings upon interference irradiation, whose grating depths correlate with head group size, demonstrating that this new class of polymers can also undergo tailored macroscopic photoinduced motions, which could have applications in all optical nano-patterning.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Frontier Photonics, Humboldt-Universität zu Berlin, McGill University, Aalto University
Contributors: Goulet-Hanssens, A., Corkery, T. C., Priimagi, A., Barrett, C. J.
Number of pages: 8
Pages: 7505-7512
Publication date: 28 Sep 2014
Peer-reviewed: Yes

Publication information

Journal: Journal of Materials Chemistry C
Volume: 2
Issue number: 36
ISSN (Print): 2050-7534
Ratings: 
  • Scopus rating (2014): CiteScore 4.64 SJR 1.517 SNIP 1.351
Original language: English
ASJC Scopus subject areas: Chemistry(all), Materials Chemistry
Source: Scopus
Source ID: 84906539664

Research output: Contribution to journalArticleScientificpeer-review

O2-requiring molecular reporters of gene expression for anaerobic microorganisms

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

General information

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

Publication information

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

Research output: Contribution to journalArticleScientificpeer-review

Membrane cholesterol access into a G-protein-coupled receptor

Cholesterol is a key component of cell membranes with a proven modulatory role on the function and ligand-binding properties of G-protein-coupled receptors (GPCRs). Crystal structures of prototypical GPCRs such as the adenosine A2A receptor (A2A R) have confirmed that cholesterol finds stable binding sites at the receptor surface suggesting an allosteric role of this lipid. Here we combine experimental and computational approaches to show that cholesterol can spontaneously enter the A2A R-binding pocket from the membrane milieu using the same portal gate previously suggested for opsin ligands. We confirm the presence of cholesterol inside the receptor by chemical modification of the A2A R interior in a biotinylation assay. Overall, we show that cholesterol's impact on A2A R-binding affinity goes beyond pure allosteric modulation and unveils a new interaction mode between cholesterol and the A2A R that could potentially apply to other GPCRs.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Research area: Computational Physics, Charité-Universitätsmedizin Berlin, Universidad de Castilla-La Mancha, Universitat Pompeu Fabra
Contributors: Guixà-González, R., Albasanz, J. L., Rodriguez-Espigares, I., Pastor, M., Sanz, F., Martí-Solano, M., Manna, M., Martinez-Seara, H., Hildebrand, P. W., Martín, M., Selent, J.
Publication date: 21 Feb 2017
Peer-reviewed: Yes

Publication information

Journal: Nature Communications
Volume: 8
Article number: 14505
ISSN (Print): 2041-1723
Ratings: 
  • Scopus rating (2017): CiteScore 12.41 SJR 6.582 SNIP 2.934
Original language: English
ASJC Scopus subject areas: Chemistry(all), Biochemistry, Genetics and Molecular Biology(all), Physics and Astronomy(all)
Source: Scopus
Source ID: 85013391445

Research output: Contribution to journalArticleScientificpeer-review

The Devil Is in the Details: What Do We Really Track in Single-Particle Tracking Experiments of Diffusion in Biological Membranes?

Single-particle tracking (SPT) is an experimental technique that allows one to follow the dynamics of individual molecules in biological membranes with unprecedented precision. Given the importance of lipid and membrane protein diffusion in the formation of nanoscale functional complexes, it is critical to understand what exactly is measured in SPT experiments. To clarify this issue, we employed nanoscale computer simulations designed to match SPT experiments that exploit streptavidin-functionalized Au nanoparticles (AuNPs). The results show that lipid labeling interferes critically with the diffusion process; thus, the diffusion measured in SPT is a far more complex process than what has been assumed. It turns out that the influence of AuNP-based labels on the dynamics of probe lipids includes not only the AuNP-induced viscous drag that is the more significant the larger the NP but, more importantly, also the effects related to the interactions of the streptavidin linker with membrane lipids. Due to these effects, the probe lipid moves in a concerted manner as a complex with the linker protein and numerous unlabeled lipids, which can slow down the motion of the probe by almost an order of magnitude. Furthermore, our simulations show that nonlinker streptavidin tetramers on the AuNP surface are able to interact with the membrane lipids, which could potentially lead to multivalent labeling of the NPs by the probe lipids. Our results further demonstrate that in the submicrosecond time domain the motion of the probe lipid is uncorrelated with the motion of the AuNP, showing that there is a 1 μs limit for the temporal resolution of the SPT technique. However, this limit for the temporal resolution depends on the nanoparticle size and increases rapidly with growing AuNPs. Overall, the results provide a molecular-scale framework to accurately interpret SPT data and to design protocols that minimize label-induced artifacts.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Research group: Biological Physics and Soft Matter, Research area: Computational Physics, Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg State University, Helsinki University, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, MEMPHYS - Center for Biomembrane Physics, Computational Physics Laboratory
Contributors: Gurtovenko, A. A., Javanainen, M., Lolicato, F., Vattulainen, I.
Number of pages: 7
Pages: 1005-1011
Publication date: 7 Mar 2019
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry Letters
Volume: 10
Issue number: 5
ISSN (Print): 1948-7185
Original language: English
ASJC Scopus subject areas: Materials Science(all), Physical and Theoretical Chemistry
Source: Scopus
Source ID: 85062352015

Research output: Contribution to journalArticleScientificpeer-review

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

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

General information

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

Publication information

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

Research output: Contribution to journalArticleScientificpeer-review

The effect of start-up on energy recovery and compositional changes in brewery wastewater in bioelectrochemical systems

Start-up of bioelectrochemical systems (BESs) fed with brewery wastewater was compared at different adjusted anode potentials (−200 and 0 mV vs. Ag/AgCl) and external resistances (50 and 1000 Ω). Current generation stabilized faster with the external resistances (9 ± 3 and 1.70 ± 0.04 A/m3 with 50 and 1000 Ω, respectively), whilst significantly higher current densities of 76 ± 39 and 44 ± 9 A/m3 were obtained with the adjusted anode potentials of −200 and 0 mV vs. Ag/AgCl, respectively. After start-up, when operated using 47 Ω external resistance, the current densities and Coulombic efficiencies of all BESs stabilized to 9.5 ± 2.9 A/m3 and 12 ± 2%, respectively, demonstrating that the start-up protocols were not critical for long-term BES operation in microbial fuel cell mode. With adjusted anode potentials, two times more biofilm biomass (measured as protein) was formed by the end of the experiment as compared to start-up with the fixed external resistances. After start-up, the organics in the brewery wastewater, mainly sugars and alcohols, were transformed to acetate (1360 ± 250 mg/L) and propionate (610 ± 190 mg/L). Optimized start-up is required for prompt BES recovery, for example, after process disturbances. Based on the results of this study, adjustment of anode potential to −200 mV vs. Ag/AgCl is recommended for fast BES start-up.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Research group: Bio- and Circular Economy
Contributors: Haavisto, J. M., Kokko, M. E., Lakaniemi, A. M., Sulonen, M. L., Puhakka, J. A.
Number of pages: 8
Publication date: 1 Apr 2020
Peer-reviewed: Yes
Early online date: 2019

Publication information

Journal: BIOELECTROCHEMISTRY
Volume: 132
Article number: 107402
ISSN (Print): 1567-5394
Original language: English
ASJC Scopus subject areas: Biophysics, Physical and Theoretical Chemistry, Electrochemistry
Keywords: Adjusted anode potential, Brewery wastewater, External resistance, Microbial fuel cell, Process recovery, Start-up protocol
Source: Scopus
Source ID: 85075970236

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 3.07 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

Analysis of free, mono- and diacetylated polyamines from human urine by LC-MS/MS

Polyamines are promising biochemical markers of cancer and many other pathophysiological conditions, and thus their concentrations in biological fluids are a matter of interest. However, since the concentrations of these compounds are low, their quantitation is typically based on methods requiring laborious sample preparation. Here we developed and validated an LC-MS/MS method to analyze simultaneously free (DAP, PUT, CAD, SPD, SPM) monoacetylated (AcPUT, AcCAD, N1AcSPD, N8AcSPD, N1AcSPM) and diacetylated (DiAcPUT, DiAcCAD, DiAcSPD, DiAcSPM) polyamines from human urine without the need for derivatization. Deuterium labeled polyamines were the internal standards for each analyte. Diluted urine samples spiked with internal standards were filtered through a strong anion exchange resin prior to LC-MS/MS analysis. The chromatographic separation of 14 polyamines was achieved in 12min on C18 column with 0.1% HFBA (v/v) as the ion-pairing agent and a water-acetonitrile gradient. Ionization was performed with positive electrospray ionization (ESI) and detection was with a triple quadrupole mass spectrometer with selected reaction monitoring. Calibration curves ranged from up to 5 to 10,000nM. The accuracy and precision of the method were determined using urine based quality control samples, and matrix effects were examined by using standard addition methods. This novel method is suitable for elucidating differences in urinary polyamine excretion in cancer patients and healthy humans.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Integrated Technologies for Tissue Engineering Research (ITTE), Ita-Suomen yliopisto, Tampere University Hospital, Karolinska University Hospital, School of Management (JKK)
Contributors: Häkkinen, M. R., Roine, A., Auriola, S., Tuokko, A., Veskimäe, E., Keinänen, T. A., Lehtimäki, T., Oksala, N., Vepsäläinen, J.
Number of pages: 9
Pages: 81-89
Publication date: 15 Dec 2013
Peer-reviewed: Yes

Publication information

Journal: JOURNAL OF CHROMATOGRAPHY B: ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES
Volume: 941
ISSN (Print): 1570-0232
Ratings: 
  • Scopus rating (2013): CiteScore 2.78 SJR 1.061 SNIP 1.278
Original language: English
ASJC Scopus subject areas: Analytical Chemistry, Biochemistry, Clinical Biochemistry, Cell Biology
Keywords: Cancer diagnostic markers, Liquid chromatography-tandem mass spectrometry, N-acetylated, Polyamines, Prostate cancer, Urine
Source: Scopus
Source ID: 84887097655

Research output: Contribution to journalArticleScientificpeer-review

Effect of Hole Transporting Material on Charge Transfer Processes in Zinc Phthalocyanine Sensitized ZnO Nanorods

The photoinduced electron transfer processes were studied for hybrid systems consisting of self-assembled monolayer of zinc phthalocyanine (ZnPc) assembled on ZnO nanorods and a film of organic hole transporting material (HTM) atop. Polythiophene (P3HT) or Spiro-OMeTAD were used as HTM. The study was carried out by ultrafast transient absorption spectroscopy technique with selective excitation of ZnPc at 680 nm or P3HT at 500 nm. Data analysis revealed that photoexcitation of ZnPc in the structure ZnO|ZnPc|P3HT results in a fast (1.8 ps) electron transfer from ZnPc to ZnO, which is followed by a hole transfer from the ZnPc cation to P3HT roughly in 30 ps. However, in the case of ZnO|ZnPc|Spiro-OMeTAD structure, the primary reaction upon excitation of ZnPc is a fast (0.5 ps) hole transfer from ZnPc to Spiro-OMeTAD, and the second step is electron injection from the ZnPc anion to ZnO in roughly 120 ps. Thus, we demonstrate two structurally very similar hybrid architectures that implement two different mechanisms for photoinduced charge separation found in dye-sensitized or in organic solar cells.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Research group: Supramolecular photochemistry
Contributors: Hakola, H., Sariola-Leikas, E., Efimov, A., Tkachenko, N. V.
Number of pages: 8
Pages: 7044-7051
Publication date: 21 Apr 2016
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry C
Volume: 120
Issue number: 13
ISSN (Print): 1932-7447
Ratings: 
  • Scopus rating (2016): CiteScore 4.48 SJR 1.964 SNIP 1.189
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Electronic, Optical and Magnetic Materials, Surfaces, Coatings and Films, Energy(all)
Source: Scopus
Source ID: 84964529902

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 10.8 SJR 5.954 SNIP 2.182
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

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 9.92 SJR 4.224 SNIP 1.769
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

The Discovery of Compounds That Stimulate the Activity of Kallikrein-Related Peptidase3 (KLK3)

Kallikrein-related peptidase3 (KLK3), also known as prostate-specific antigen (PSA), is the most useful biomarker for prostate cancer (PCa). KLK3 is suggested to play a role in regulating cancer growth through anti-angiogenic activity invivo and invitro. This feature, together with its specificity for prostate tissue, makes KLK3 an intriguing target for the design of new therapies for PCa. 3D pharmacophores for KLK3-stimulating compounds were generated based on peptides that bind specifically to KLK3 and increase its enzymatic activity. As a result of pharmacophore-based virtual screening, four small, drug-like compounds with affinity for KLK3 were discovered and validated by capillary differential scanning calorimetry. One of the compounds also stimulated the activity of KLK3, and is therefore the first published small molecule with such an activity. Target specificity: Successful 3D pharmacophore-based virtual screening resulted in the first small, drug-like molecule that stimulates the activity of kallikrein-related peptidase3 (KLK3, PSA). The compound discovered can be applied to the design of novel KLK3-stimulating compounds with the potential to inhibit tumor angiogenesis and progression of prostate cancer.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Multi-scaled biodata analysis and modelling (MultiBAM), Ita-Suomen yliopisto, Helsinki University Central Hospital, Tampere University Hospital, Kobenhavns Universitet, European ScreeningPort GmbH
Contributors: Härkönen, H. H., Mattsson, J. M., Määttä, J. A. E., Stenman, U. H., Koistinen, H., Matero, S., Windshügel, B., Poso, A., Lahtela-Kakkonen, M.
Number of pages: 9
Pages: 2170-2178
Publication date: 9 Dec 2011
Peer-reviewed: Yes

Publication information

Journal: CHEMMEDCHEM
Volume: 6
Issue number: 12
ISSN (Print): 1860-7179
Ratings: 
  • Scopus rating (2011): CiteScore 3.24 SJR 1.267 SNIP 0.933
Original language: English
ASJC Scopus subject areas: Molecular Medicine, Pharmacology, Toxicology and Pharmaceutics(all), Organic Chemistry
Keywords: Angiogenesis, Kallikrein, Molecular modeling, Peptides, Virtual screening
Source: Scopus
Source ID: 82955165662

Research output: Contribution to journalArticleScientificpeer-review

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

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

General information

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

Publication information

Journal: Journal of Coatings Technology Research
Volume: 15
Issue number: 3
ISSN (Print): 1547-0091
Ratings: 
  • Scopus rating (2018): CiteScore 1.66
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

Polymorph crystal packing effects on charge transfer emission in the solid state

Condensation of 1,8-naphthalic anhydride with N,N-(dimethylamino)aniline produced the donor-acceptor compound DMIM, which crystallised from a chloroform-diethyl ether mixture to afford two different coloured crystal polymorphs. Crystals for one polymorph are small and green, whereas the other crystals are orange and needle-like. X-ray crystal structures for both polymorphs were determined. The donor N,N-dimethylaniline and acceptor naphthalimide groups are twisted with respect to each other; the degree of twist is marginally different for the two structures. The orange crystal polymorph crystallises in the monoclinic space group C2/c and contains two slightly different molecular conformers in the unit cell (calculated density is 1.410 g cm<sup>-3</sup>). The green crystal polymorph crystallises in the triclinic space group P1 and contains only one type of molecule in the unit cell (calculated density is 1.401 g cm<sup>-3</sup>). The crystal packing motifs for the two polymorphs are subtly different, explaining the small variance in the observed densities. Very weak room temperature emission was observed for DMIM in a CHCl<inf>3</inf> solution, but crystals deposited on a glass slide glowed when irradiated at 488 nm using a fluorescence microscope. Disparate solid-state emission spectra and lifetimes for the two polymorphic crystal forms are observed for the dyad. The emission is assigned to charge recombination fluorescence from a charge transfer state. This journal is

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Research group: Supramolecular photochemistry, Molecular Photonics Laboratory, School of Chemistry, Newcastle University, United Kingdom, University of Malta
Contributors: He, X., Benniston, A. C., Saarenpää, H., Lemmetyinen, H., Tkachenko, N. V., Baisch, U.
Number of pages: 8
Pages: 3525-3532
Publication date: 1 Jun 2015
Peer-reviewed: Yes

Publication information

Journal: Chemical Science
Volume: 6
Issue number: 6
ISSN (Print): 2041-6520
Ratings: 
  • Scopus rating (2015): CiteScore 9.13 SJR 4.647 SNIP 1.718
Original language: English
ASJC Scopus subject areas: Chemistry(all)
Source: Scopus
Source ID: 84929589670

Research output: Contribution to journalArticleScientificpeer-review

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

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

General information

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

Publication information

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

Research output: Contribution to journalArticleScientificpeer-review

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 3.49 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

Urea and guanidinium induced denaturation of a Trp-cage miniprotein

Using a combination of experimental techniques (circular dichroism, differential scanning calorimetry, and NMR) and molecular dynamics simulations, we performed an extensive study of denaturation of the Trp-cage miniprotein by urea and guanidinium. The experiments, despite their different sensitivities to various aspects of the denaturation process, consistently point to simple, two-state unfolding process. Microsecond molecular dynamics simulations with a femtosecond time resolution allow us to unravel the detailed molecular mechanism of Trp-cage unfolding. The process starts with a destabilizing proline shift in the hydrophobic core of the miniprotein, followed by a gradual destruction of the hydrophobic loop and the α-helix. Despite differences in interactions of urea vs guanidinium with various peptide moieties, the overall destabilizing action of these two denaturants on Trp-cage is very similar.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Computational Science X (CompX), Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, University of Leeds
Contributors: Heyda, J., Kožíšek, M., Bednárova, L., Thompson, G., Konvalinka, J., Vondrášek, J., Jungwirth, P.
Number of pages: 15
Pages: 8910-8924
Publication date: 21 Jul 2011
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry Part B
Volume: 115
Issue number: 28
ISSN (Print): 1520-6106
Ratings: 
  • Scopus rating (2011): CiteScore 3.62 SJR 1.801 SNIP 1.223
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Materials Chemistry, Surfaces, Coatings and Films
Source: Scopus
Source ID: 79960344032

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 10.8 SJR 5.954 SNIP 2.182
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

Hexaphyrin as a Potential Theranostic Dye for Photothermal Therapy and 19F Magnetic Resonance Imaging

Two features of meso-Aryl-substituted expanded porphyrins suggest suitability as theranostic agents. They have excellent absorption in near infrared (NIR) region, and they offer the possibility of introduction of multiple fluorine atoms at structurally equivalent positions. Here, hexaphyrin (hexa) was synthesized from 2,6-bis(trifluoromethyl)-4-formyl benzoate and pyrrole and evaluated as a novel expanded porphyrin with the above features. Under NIR illumination hexa showed intense photothermal and weak photodynamic effects, which were most likely due to its low excited states, close to singlet oxygen. The sustained photothermal effect caused ablation of cancer cells more effectively than the photodynamic effect of indocyanine green (a clinical dye). In addition, hexa showed potential for use in the visualization of tumors by 19F magnetic resonance imaging (MRI), because of the multiple fluorine atoms. Our results strongly support the utility of expanded porphyrins as theranostic agents in both photothermal therapy and 19F MRI.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Chemistry & Advanced Materials, Kyoto Women's University, Toyama Prefectural University
Contributors: Higashino, T., Nakatsuji, H., Fukuda, R., Okamoto, H., Imai, H., Matsuda, T., Tochio, H., Shirakawa, M., Tkachenko, N. V., Hashida, M., Murakami, T., Imahori, H.
Number of pages: 9
Pages: 951-959
Publication date: 24 Mar 2017
Peer-reviewed: Yes

Publication information

Journal: ChemBioChem
Volume: 18
Issue number: 10
ISSN (Print): 1439-4227
Ratings: 
  • Scopus rating (2017): CiteScore 2.64 SJR 1.407 SNIP 0.726
Original language: English
ASJC Scopus subject areas: Biochemistry, Molecular Medicine, Molecular Biology, Organic Chemistry
Keywords: expanded porphyrin, fluorine, MRI, NMR spectroscopy, photochemistry, theranostics
Source: Scopus
Source ID: 85016610793

Research output: Contribution to journalArticleScientificpeer-review

Epitaxial phases of high Bi content GaSbBi alloys

GaSbBi alloys have recently emerged as attractive materials for mid-infrared optoelectronics owing to strong band gap reduction enabled by Bi incorporation into the GaSb matrix. The fundamental understanding of the epitaxial process required to demonstrate high quality crystals is in an early-developmental phase. From this perspective, we report on the key role played by the Sb/Ga flux ratio in controlling the structural quality and incorporation of high Bi content GaSbBi (up to 14.5%-Bi), revealing three distinct epitaxial phases. The first phase (below stoichiometric Sb/Ga) exhibits Ga-Bi compound droplets, low crystal quality, and reduced Bi content. At the second phase (above stoichiometric Sb/Ga), the crystal exhibits smooth surfaces and excellent crystallinity with efficient Bi incorporation. The last phase corresponds to exceeding a Sb/Ga threshold that leads to reduced Bi incorporation, Bi droplets and degraded crystallinity. This threshold value that defines the optimal growth window is controlled by the temperature as well as the Bi/Ga ratio. Increasing temperature increases the threshold, albeit simultaneously reducing Bi incorporation. Conversely, increasing the Bi/Ga flux ratio increases Bi incorporation, while narrowing down and ultimately closing the window. This study provides a general framework enabling development of high quality GaSbBi heterostructures for emerging mid-infrared optoelectronics.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Research group: ORC
Contributors: Hilska, J., Koivusalo, E., Puustinen, J., Suomalainen, S., Guina, M.
Number of pages: 5
Pages: 67-71
Publication date: 15 Jun 2019
Peer-reviewed: Yes

Publication information

Journal: Journal of Crystal Growth
Volume: 516
ISSN (Print): 0022-0248
Original language: English
ASJC Scopus subject areas: Condensed Matter Physics, Inorganic Chemistry, Materials Chemistry
Keywords: A3. Molecular beam epitaxy, B1. Antimonides, B1. Bismuth compounds, B2. Semiconducting III-V materials, B2. Semiconducting ternary compounds
Source: Scopus
Source ID: 85063780657

Research output: Contribution to journalArticleScientificpeer-review

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

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

General information

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

Publication information

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

Research output: Contribution to journalArticleScientificpeer-review

Release of halide ions from the buried active site of the haloalkane dehalogenase LinB revealed by stopped-flow fluorescence analysis and free energy calculations

Release of halide ions is an essential step of the catalytic cycle of haloalkane dehalogenases. Here we describe experimentally and computationally the process of release of a halide anion from the buried active site of the haloalkane dehalogenase LinB. Using stopped-flow fluorescence analysis and umbrella sampling free energy calculations, we show that the anion binding is ion-specific and follows the ordering I- > Br- > Cl-. We also address the issue of the protonation state of the catalytic His272 residue and its effect on the process of halide release. While deprotonation of His272 increases binding of anions in the access tunnel, we show that the anionic ordering does not change with the switch of the protonation state. We also demonstrate that a sodium cation could relatively easily enter the active site, provided the His272 residue is singly protonated, and replace thus the missing proton. In contrast, Na+ is strongly repelled from the active site containing the doubly protonated His272 residue. Our study contributes toward understanding of the reaction mechanism of haloalkane dehalogenase enzyme family. Determination of the protonation state of the catalytic histidine throughout the catalytic cycle remains a challenge for future studies.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Computational Science X (CompX), Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Masaryk University
Contributors: Hladilkova, J., Prokop, Z., Chaloupkova, R., Damborsky, J., Jungwirth, P.
Number of pages: 7
Pages: 14329-14335
Publication date: 21 Nov 2013
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry Part B
Volume: 117
Issue number: 46
ISSN (Print): 1520-6106
Ratings: 
  • Scopus rating (2013): CiteScore 3.53 SJR 1.504 SNIP 1.194
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Materials Chemistry, Surfaces, Coatings and Films
Source: Scopus
Source ID: 84888618153

Research output: Contribution to journalArticleScientificpeer-review

Hydration of hydroxyl and amino groups examined by molecular dynamics and neutron scattering

Neutron diffraction with isotopic substitution was performed on aqueous solutions of isopropyl alcohol and isopropylamine. The difference between these two measurements primarily contains information about the different hydration of the alcohol and amino group. This data is used as a test of the accuracy of molecular dynamic simulations of the same systems. Having established the level of accuracy of the modeling, it is employed as an interpretive tool for the experimental data. Even though the alcohol and the amine possess comparable hydrogen bonding capabilities, consisting respectively of either two hydrogen bond acceptors and one donor, or two hydrogen bond donors and one acceptor, we find significant differences in the hydration of the hydroxyl and amino groups.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Computational Science X (CompX), Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Institut Laue-Langevin
Contributors: Hladílková, J., Fischer, H. E., Jungwirth, P., Mason, P. E.
Number of pages: 9
Pages: 6357-6365
Publication date: 28 May 2015
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry Part B
Volume: 119
Issue number: 21
ISSN (Print): 1520-6106
Ratings: 
  • Scopus rating (2015): CiteScore 3.25 SJR 1.335 SNIP 1.058
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Materials Chemistry, Surfaces, Coatings and Films
Source: Scopus
Source ID: 84930682015

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 6.99 SJR 2.397 SNIP 1.839
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 7.6 SJR 2.254 SNIP 1.715
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

Controllable Electronic Structures and Photoinduced Processes of Bay-Linked Perylenediimide Dimers and a Ferrocene-Linked Triad

A series of perylene-3,4,9,10-bis(dicarboximide) (PDI) dimers linked through the bay regions was systematically synthesized to examine the electronic structures and photophysical properties in dependence on the distance and orientation between the two PDI units. The spectroscopic and electrochemical measurements suggested that the coupling value of a directly linked PDI dimer (PDI)2 is much larger than those of para- and meta-phenylene-bridged PDI dimers p-(PDI)2 and m-(PDI)2. The width of Davydov splitting was quantitatively evaluated to compare the coupling values between the two PDI units in these dimers by absorption spectroscopy in frozen 2-methyl-THF. Excimer formation of PDI dimers induced the strong fluorescence quenching and large red-shifts. Femtosecond transient absorption revealed a broad absorption derived from an excimer in the range from about 600nm to the near-IR region. The rate constants of formation and decay of the excimer are strongly dependent on the coupling values. Time-resolved measurements on ferrocene-linked p-(PDI)2 revealed a competition between the photoinduced processes of electron transfer and excimer formation in PhCN, which is in sharp contrast with the sole electron-transfer process in toluene.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Research group: Supramolecular photochemistry
Contributors: Horinouchi, H., Sakai, H., Araki, Y., Sakanoue, T., Takenobu, T., Wada, T., Tkachenko, N. V., Hasobe, T.
Pages: 9631-9641
Publication date: 2016
Peer-reviewed: Yes

Publication information

Journal: Chemistry: A European Journal
Volume: 22
Issue number: 28
ISSN (Print): 0947-6539
Ratings: 
  • Scopus rating (2016): CiteScore 5.03 SJR 2.352 SNIP 1.082
Original language: English
ASJC Scopus subject areas: Chemistry(all)
Keywords: Electron transfer, Electronic structure, Excimers, Perylenediimides, Photophysics
Source: Scopus
Source ID: 84973522054

Research output: Contribution to journalArticleScientificpeer-review

Appropriate pricing policy needed worldwide for improving water services infrastructure

This article highlights the enormous and growing gap between the projected and required financing of water services infrastructure, which is caused by unviable pricing and/or costrecovery regimes. Globally there is a growing funding gap in rehabilitation, renewal, and replacement of aging water infrastructure and the need for future greenfield investments. Underpricing of water services and the need for rehabilitation seem to be worldwide phenomena. There are diverse constraints in OECD (Organisation for Economic Co-Operation and Development) and non-OECD countries contributing to underpriced water services; however, the message is clear: the global water industry must stop underpricing precious water resources. Future enjoyment of sustainable water services will require customers to bear all or at least a major part of the costs. Better awareness of broader economic and social benefits of water supply, and particularly of sanitation, also will be needed.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Chemistry and Bioengineering, Life Cycle Effectiveness of the Built Environment (LCE@BE)
Contributors: Hukka, J. J., Katko, T. S.
Pages: E37-E46
Publication date: 1 Jan 2015
Peer-reviewed: Yes

Publication information

Journal: Journal American Water Works Association
Volume: 107
Issue number: 1
ISSN (Print): 0003-150X
Ratings: 
  • Scopus rating (2015): CiteScore 0.41 SJR 0.401 SNIP 0.641
Original language: English
ASJC Scopus subject areas: Water Science and Technology, Chemistry(all)
Keywords: Aging and deteriorating infrastructure, Pricing, Sustainability, Sustainable cost recovery, Underpricing, Water services infrastructure
Source: Scopus
Source ID: 84920619765

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 6.76 SJR 2.131 SNIP 2.595
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

Protein conformation as a regulator of cell-matrix adhesion

The dynamic regulation of cell-matrix adhesion is essential for tissue homeostasis and architecture, and thus numerous pathologies are linked to altered cell-extracellular matrix (ECM) interaction and ECM scaffold. The molecular machinery involved in cell-matrix adhesion is complex and involves both sensory and matrix-remodelling functions. In this review, we focus on how protein conformation controls the organization and dynamics of cell-matrix adhesion. The conformational changes in various adhesion machinery components are described, including examples from ECM as well as cytoplasmic proteins. The discussed mechanisms involved in the regulation of protein conformation include mechanical stress, post-translational modifications and allosteric ligand-binding. We emphasize the potential role of intrinsically disordered protein regions in these processes and discuss the role of protein networks and co-operative protein interactions in the formation and consolidation of cell-matrix adhesion and extracellular scaffolds.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Multi-scaled biodata analysis and modelling (MultiBAM), Fimlab Laboratories Ltd, University of Geneva
Contributors: Hytönen, V. P., Wehrle-Haller, B.
Number of pages: 16
Pages: 6342-6357
Publication date: 14 Apr 2014
Peer-reviewed: Yes

Publication information

Journal: Physical Chemistry Chemical Physics
Volume: 16
Issue number: 14
ISSN (Print): 1463-9076
Ratings: 
  • Scopus rating (2014): CiteScore 4.29 SJR 1.771 SNIP 1.231
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Physics and Astronomy(all)
Source: Scopus
Source ID: 84896364401

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 4.05 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

Inequivalence of single CHa and CHb methylene bonds in the interior of a diunsaturated lipid bilayer from a molecular dynamics simulation

Orientational order parameters for individual CHa and CHb bonds are local measures for the alignment of the bonds in a membrane interior. Experimental values exist for some lipid systems but no results are available from molecular dynamics (MD) simulations, although they are increasingly used to study biomembranes. We present such detailed analysis of a one nanosecond MD simulation for a PLPC (16:0/18:2Δ9.12) bilayer. The results show marked inequivalence for the CHa and CHb bonds of the methylene segments in the beginning and in the double bond region of the diunsaturated sn-2 chain. They also suggest slight inequivalences in the saturated chain.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Ita-Suomen yliopisto, University of Oulu, Department of Physical Sciences
Contributors: Hyvönen, M., Ala-Korpela, M., Vaara, J., Rantala, T. T., Jokisaari, J.
Number of pages: 6
Pages: 55-60
Publication date: 4 Apr 1997
Peer-reviewed: Yes

Publication information

Journal: Chemical Physics Letters
Volume: 268
Issue number: 1-2
ISSN (Print): 0009-2614
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Spectroscopy, Atomic and Molecular Physics, and Optics
Source: Scopus
Source ID: 0031552317

Research output: Contribution to journalArticleScientificpeer-review

Effects of two double bonds on the hydrocarbon interior of a phospholipid bilayer

A phospholipid bilayer was modelled by duplicating a monolayer system of 36 1-palmitoyl-2-linoleoyl-sn-glycero-3-phosphatidylcholine (PLPC) molecules ( 16:0 18:2) plus 1368 water molecules and simulated using molecular dynamics. The analyses revealed distinct characteristics in the membrane structure due to polyunsaturation. The orientational behaviour of the fatty acid chains in the PLPC bilayer was found to be seemingly different from that in monounsaturated or in saturated phospholipid bilayers. The specific attributes responsible for the observed behaviour of the saturated and polyunsaturated chains are discussed and their relative importance assessed.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: University of Oulu, Hammersmith Hospital, Department of Physical Sciences
Contributors: Hyvönen, M., Ala-Korpela, M., Vaara, J., Rantala, T. T., Jokisaari, J.
Number of pages: 7
Pages: 300-306
Publication date: 24 Nov 1995
Peer-reviewed: Yes

Publication information

Journal: Chemical Physics Letters
Volume: 246
Issue number: 3
ISSN (Print): 0009-2614
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Physics and Astronomy(all)
Source: Scopus
Source ID: 4243491046

Research output: Contribution to journalArticleScientificpeer-review

MetrIntSimil-an accurate and robust metric for comparison of similarity in intelligence of any number of cooperative multiagent systems

Intelligent cooperative multiagent systems are applied for solving a large range of real-life problems, including in domains like biology and healthcare. There are very few metrics able to make an effective smeasure of the machine intelligence quotient. The most important drawbacks of the designed metrics presented in the scientific literature consist in the limitation in universality, accuracy, and robustness. In this paper, we propose a novel universal metric called MetrIntSimil capable of making an accurate and robust symmetric comparison of the similarity in intelligence of any number of cooperative multiagent systems specialized in difficult problem solving. The universality is an important necessary property based on the large variety of designed intelligent systems. MetrIntSimil makes a comparison by taking into consideration the variability in intelligence in the problem solving of the compared cooperativemultiagent systems. It allows a classification of the cooperativemultiagent systems based on their similarity in intelligence. A cooperative multiagent system has variability in the problem solving intelligence, and it can manifest lower or higher intelligence in different problem solving tasks. More cooperative multiagent systems with similar intelligence can be included in the same class. For the evaluation of the proposed metric, we conducted a case study for more intelligent cooperative multiagent systems composed of simple computing agents applied for solving the Symmetric Travelling Salesman Problem (STSP) that is a class of NP-hard problems. STSP is the problem of finding the shortest Hamiltonian cycle/tour in a weighted undirected graph that does not have loops or multiple edges. The distance between two cities is the same in each opposite direction. Two classes of similar intelligence denoted IntClassA and IntClassB were identified. The experimental results show that the agent belonging to IntClassA intelligence class is less intelligent than the agents that belong to the IntClassB intelligence class.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Research group: Computational Medicine and Statistical Learning Laboratory (CMSL), Faculty of Biomedical Sciences and Engineering, Research group: Predictive Society and Data Analytics (PSDA), Petru Maior University, University of Applied Sciences Upper Austria, Nankai University, Institute for Bioinformatics and Translational Research
Contributors: Iantovics, L. B., Dehmer, M., Emmert-Streib, F.
Publication date: 1 Feb 2018
Peer-reviewed: Yes

Publication information

Journal: Symmetry
Volume: 10
Issue number: 2
Article number: 48
ISSN (Print): 2073-8994
Ratings: 
  • Scopus rating (2018): CiteScore 2.28 SJR 0.287 SNIP 1.046
Original language: English
ASJC Scopus subject areas: Computer Science (miscellaneous), Chemistry (miscellaneous), Mathematics(all), Physics and Astronomy (miscellaneous)
Keywords: Computational-hard problem, Cooperative problem solving, Diversity of intelligent systems, Machine intelligence measure, Similarity in intelligence, Symmetric travelling salesman problem
Electronic versions: 
Source: Scopus
Source ID: 85042547076

Research output: Contribution to journalArticleScientificpeer-review

Differential basal-to-apical accessibility of lamin A/C epitopes in the nuclear lamina regulated by changes in cytoskeletal tension

Nuclear lamins play central roles at the intersection between cytoplasmic signalling and nuclear events. Here, we show that at least two N- and C-terminal lamin epitopes are not accessible at the basal side of the nuclear envelope under environmental conditions known to upregulate cell contractility. The conformational epitope on the Ig-domain of A-type lamins is more buried in the basal than apical nuclear envelope of human mesenchymal stem cells undergoing osteogenesis (but not adipogenesis), and in fibroblasts adhering to rigid (but not soft) polyacrylamide hydrogels. This structural polarization of the lamina is promoted by compressive forces, emerges during cell spreading, and requires lamin A/C multimerization, intact nucleoskeleton-cytoskeleton linkages (LINC), and apical-actin stress-fibre assembly. Notably, the identified Ig-epitope overlaps with emerin, DNA and histone binding sites, and comprises various laminopathy mutation sites. Our findings should help decipher how the physical properties of cellular microenvironments regulate nuclear events.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Integrated Technologies for Tissue Engineering Research (ITTE), Laboratory of Applied Mechanobiology, HCI e 486.1
Contributors: Ihalainen, T. O., Aires, L., Herzog, F. A., Schwartlander, R., Moeller, J., Vogel, V.
Number of pages: 10
Pages: 1252-1261
Publication date: 1 Dec 2015
Peer-reviewed: Yes

Publication information

Journal: Nature Materials
Volume: 14
Issue number: 12
ISSN (Print): 1476-1122
Ratings: 
  • Scopus rating (2015): CiteScore 25.58 SJR 16.382 SNIP 8.962
Original language: English
ASJC Scopus subject areas: Mechanical Engineering, Mechanics of Materials, Condensed Matter Physics, Materials Science(all), Chemistry(all)
Source: Scopus
Source ID: 84947870719

Research output: Contribution to journalArticleScientificpeer-review

Strain rate change tests with the Split Hopkinson Bar method

In this paper, methods to produce rapid strain rate changes for strain rate sensitivity measurements in Split Hopkinson Bar arrangements are presented and discussed. Two different cases are considered: a strain rate change test within the high strain rate region in compression, and a tension test incorporating a large strain rate jump directly from the low strain rate region to high strain rates. The former method is based on the loading wave amplitude manipulation, while the latter method is based on the incorporation of a low strain rate loading device into a Tensile Split Hopkinson Bar apparatus.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Materials Science, Research group: Materials Characterization
Contributors: Isakov, M., Kokkonen, J., Östman, K., Kuokkala, V.
Pages: 231-242
Publication date: 1 Apr 2016
Peer-reviewed: Yes

Publication information

Journal: European Physical Journal. Special Topics
Volume: 225
Issue number: 2
ISSN (Print): 1951-6355
Ratings: 
  • Scopus rating (2016): CiteScore 1.94 SJR 0.581 SNIP 0.793
Original language: English
ASJC Scopus subject areas: Physics and Astronomy(all), Materials Science(all), Physical and Theoretical Chemistry
Source: Scopus
Source ID: 84941343460

Research output: Contribution to journalArticleScientificpeer-review

Systematic analysis of coating-substrate interactions in the presence of flow localization

Localized deformation and cracking in a system of thermally sprayed hard metal coating overlaid on a low alloy steel is studied by means of bend testing. In-situ digital image correlation measurements are used to characterize material strain field near the coating/substrate interface. The studied substrate undergoes softening upon yielding which manifests itself as narrow bands of localized shear deformation. The measurements show that the coating cracks and the substrate shear bands interact. When the coating starts cracking during the elastic loading of the substrate, the formed cracks function as nucleation points for the shear bands. In contrast, if the coating resists cracking until the yielding of the substrate, the coating cracks and substrate shear bands form simultaneously. Based on the experiments, continuum-scale finite element model of the system is developed, validated and then used for a systematic numerical analysis of the effects of substrate shear banding on the measurement of coating properties. Based on the results of this work, three main effects can be identified. Firstly, the flow localization in the substrate can increase the measured apparent (macroscopic) surface strain of the coating, if not accounted for by using microscopic techniques. Secondly, substrate shear bands increase the interfacial loading, which may cause unexpected delamination of the coating and thus affect the evaluation of the interfacial strength. Finally, substrate shear bands affect the stress state within the coating and may thus affect the cracking morphology in the coating. Therefore, based on the results of this study, if the coating and interfacial strengths are of similar magnitude with the substrate yield strength, the possible tendency of the substrate towards flow localization should be taken into account in the analysis of the coating behavior.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science, Research group: Surface Engineering, Ernst-Mach-Institut
Contributors: Isakov, M., Matikainen, V., Koivuluoto, H., May, M.
Number of pages: 17
Pages: 264-280
Publication date: 15 Sep 2017
Peer-reviewed: Yes

Publication information

Journal: Surface and Coatings Technology
Volume: 324
ISSN (Print): 0257-8972
Ratings: 
  • Scopus rating (2017): CiteScore 3.08 SJR 0.928 SNIP 1.565
Original language: English
ASJC Scopus subject areas: Chemistry(all), Condensed Matter Physics, Surfaces and Interfaces, Surfaces, Coatings and Films, Materials Chemistry
Keywords: Bending, Digital image correlation, Finite element method, Hard metal coating, Interfacial strength, Shear band
Electronic versions: 
URLs: 
Source: Scopus
Source ID: 85019992522

Research output: Contribution to journalArticleScientificpeer-review

Measuring optical anisotropy in poly(3,4-ethylene dioxythiophene): poly(styrene sulfonate) films with added graphene

Abstract Graphene is a 2D nanomaterial having a great potential for applications in electronics and optoelectronics. Composites of graphene with conducting polymers have shown high performance in practical devices and their solution-processability enables low-cost and high-throughput mass manufacturing using printing techniques. Here we measure the effect of incorporation of graphene into poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) to the optical anisotropy, absorbance and conductivity of the film. Uniaxial anisotropy in PEDOT:PSS films has been thought to be caused by the spin-coating process used in fabrication. We have characterized spray- and spin-coated films using ellipsometry and total internal reflection spectroscopy, the latter especially for films too thick and uneven for ellipsometry, and show that spray-coating, similar to inkjet printing, also produces consistently anisotropic properties even in very thick and uneven films. Possible plasmonic excitations related to graphene are not seen in the films. The optical and electrical anisotropy of graphene/PEDOT:PSS enables routes to high performance devices for electronics, photonics and optoelectronics.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Automation Science and Engineering, Research area: Microsystems, Research area: Measurement Technology and Process Control, Integrated Technologies for Tissue Engineering Research (ITTE), Miktech Oy, University of Jyväskylä
Contributors: Isoniemi, T., Tuukkanen, S., Cameron, D. C., Simonen, J., Toppari, J. J.
Number of pages: 7
Pages: 317-323
Publication date: 9 Jul 2015
Peer-reviewed: Yes

Publication information

Journal: Organic Electronics
Volume: 25
ISSN (Print): 1566-1199
Ratings: 
  • Scopus rating (2015): CiteScore 3.6 SJR 1.135 SNIP 1.082
Original language: English
ASJC Scopus subject areas: Biomaterials, Electronic, Optical and Magnetic Materials, Materials Chemistry, Electrical and Electronic Engineering, Chemistry(all), Condensed Matter Physics
Keywords: PEDOT: PSS, Graphene, Anisotropy, Spectroscopy, Conducting polymer, CARBON-NANOTUBE, ELECTRONICS, OPTOELECTRONICS, CONDUCTIVITY, TRANSPARENT, PHOTONICS, GROWTH, CELLS

Bibliographical note

Versio ja lupa ok 13.1.2016 /KK
EXT="Simonen, Janne"

Source: Scopus
Source ID: 84936759109

Research output: Contribution to journalArticleScientificpeer-review

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

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

General information

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

Publication information

Journal: Corrosion
Volume: 72
Issue number: 6
ISSN (Print): 0010-9312
Ratings: 
  • Scopus rating (2016): CiteScore 2.02 SJR 1.075 SNIP 1.496
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

Feed-hopper level estimation and control in cone crushers

This paper describes a novel feed-hopper level estimation and control scheme for addressing the known problem of unreliable and occasionally corrupted feed-hopper level measurement in a cone crusher. The approach involves estimating the feed-hopper level with an adaptive time-variant state estimator. The proposed adaptive scheme delivers asymptotically unbiased feed-hopper level estimates, despite using an inherently biased state estimator with biased measurement(s) and/or model, and therefore addresses the common pitfall of state estimators. The paper details the entire control system design procedure, from the fundamental theory, through dynamic modeling and estimator/controller tuning, to the design validation and control performance evaluation. The performance of the proposed scheme is evaluated through extensive full-scale tests in various production scenarios, including process start-up, level setpoint changes, and mass flow disturbance rejection. The full-scale tests revealed a number of benefits compared to the straightforward level control implementation. These benefits include the possibility of recovering from a temporary loss of measurement signal, smaller control effort, and increased system robustness due to an increased ability to withstand measurement errors. Therefore, the proposed scheme will enable more consistent size reduction and provide protection against performance degradation and process down-time.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Automation and Hydraulic Engineering, Chalmers University of Technology
Contributors: Itävuo, P., Hulthén, E., Vilkko, M.
Number of pages: 14
Pages: 82-95
Publication date: 15 Aug 2017
Peer-reviewed: Yes

Publication information

Journal: Minerals Engineering
Volume: 110
ISSN (Print): 0892-6875
Ratings: 
  • Scopus rating (2017): CiteScore 2.99 SJR 1.248 SNIP 2.073
Original language: English
ASJC Scopus subject areas: Control and Systems Engineering, Chemistry(all), Geotechnical Engineering and Engineering Geology, Mechanical Engineering
Keywords: Adaptive state estimation, Cone crusher, Dynamic modeling, Level control, System identification
Source: Scopus
Source ID: 85018328452

Research output: Contribution to journalArticleScientificpeer-review

Mass balance control of crushing circuits

This paper describes a novel circuit-wide control scheme that addresses the challenging problem of mass balance control of crushing circuits. The control objective is to ensure 100% utilization at the circuit bottleneck and hence push the realized performance towards the theoretical maximum. The present control problem is challenging due to long transport delays, complex circuit layout, under-actuated process, several uncontrolled disturbance flows, varying number of active equipment, varying downstream demand, and changing bottleneck location. The proposed mass balance control scheme involves feeding the circuit according to actual demand and realized circuit throughput, whilst maintaining the amount of material accumulated into the circuit and ensuring the physical integrity of the circuit. Therefore, the circuit feeding is based on the realized processing capacity, rather than an individual bin level or an operator decision. To ensure the efficient use of available surge capacity, a limiting control structure is proposed to simultaneously realize the in-circuit multi-objective limit violation control and loose bin level control strategy. The proposed scheme offers a simple solution for the otherwise complex control problem, which can be easily and efficiently implemented using classic control methods. The paper details an entire design procedure, from the fundamental theory, through dynamic modeling and controller tuning, to the complete circuit control system design and implementation. The proposed scheme is evaluated under extensive full-scale and simulated experiments at various production scenarios and equipment combinations. The rigorous control experiments revealed that the proposed scheme delivered the desired behavior in every possible scenario. This enables the circuit to reach its true potential.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Automation Technology and Mechanical Engineering, Research group: Automation and Systems Theory, Chalmers University of Technology, University of Queensland
Contributors: Itävuo, P., Hulthén, E., Yahyaei, M., Vilkko, M.
Number of pages: 11
Pages: 37-47
Publication date: May 2019
Peer-reviewed: Yes

Publication information

Journal: Minerals Engineering
Volume: 135
ISSN (Print): 0892-6875
Original language: English
ASJC Scopus subject areas: Control and Systems Engineering, Chemistry(all), Geotechnical Engineering and Engineering Geology, Mechanical Engineering
Keywords: Crushing, Dynamic modeling, Limiting control, Mass balance control, Sensor fusion
Source: Scopus
Source ID: 85062035841

Research output: Contribution to journalArticleScientificpeer-review

Reaction between Peroxy and Alkoxy Radicals Can Form Stable Adducts

Peroxy (RO 2 ) and alkoxy (RO) radicals are prototypical intermediates in any hydrocarbon oxidation. In this work, we use computational methods to (1) study the mechanism and kinetics of the RO 2 + OH reaction for previously unexplored "R" structures (R = CH(O)CH 2 and R = CH 3 C(O)) and (2) investigate a hitherto unaccounted channel of molecular growth, R′O 2 + RO. On the singlet surface, these reactions rapidly form ROOOH and R′OOOR adducts, respectively. The former decomposes to RO + HO 2 and R(O)OH + O 2 products, while the main decomposition channel for the latter is back to the reactant radicals. Decomposition rates of R′OOOR adducts varied between 103 and 0.015 s -1 at 298 K and 1 atm. The most long-lived R′OOOR adducts likely account for some fraction of the elemental compositions detected in the atmosphere that are commonly assigned to stable covalently bound dimers.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, University of Helsinki
Contributors: Iyer, S., Rissanen, M. P., Kurtén, T.
Number of pages: 7
Pages: 2051-2057
Publication date: 2 May 2019
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry Letters
Volume: 10
Issue number: 9
ISSN (Print): 1948-7185
Original language: English
ASJC Scopus subject areas: Materials Science(all), Physical and Theoretical Chemistry
Electronic versions: 
Source: Scopus
Source ID: 85064871304

Research output: Contribution to journalArticleScientificpeer-review

Magnetic routing of light-induced waveguides

Among photofunctional materials that can be employed to control the propagation of light by modifying their properties, soft dielectrics such as nematic liquid crystals (NLCs) stand out for their large all-optical response. Through reorientation, the molecular distribution of NLCs can be modified by the electric field of light, permitting functional operations and supporting self-localized light beams or spatial optical solitons. To date, the generation and routing of such solitons have been limited by the boundary conditions employed to tailor the properties of NLCs in planar cells or capillaries. Here we report on spatial solitons in bulk NLCs with no lateral anchoring, where the application of an external magnetic field effectively controls the direction of propagation and the angular steering of the self-trapped wavepackets. Our results entail a completely new approach to the routing of self-localized beams and light-induced waveguides in three dimensions, without the usual limitations imposed by transverse boundary conditions.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Australian National University, Nonlinear Optics and OptoElectronics Lab, University “Roma Tre”, Texas A and M University at Qatar
Contributors: Izdebskaya, Y., Shvedov, V., Assanto, G., Krolikowski, W.
Publication date: 15 Feb 2017
Peer-reviewed: Yes

Publication information

Journal: Nature Communications
Volume: 8
Article number: 14452
ISSN (Print): 2041-1723
Ratings: 
  • Scopus rating (2017): CiteScore 12.41 SJR 6.582 SNIP 2.934
Original language: English
ASJC Scopus subject areas: Chemistry(all), Biochemistry, Genetics and Molecular Biology(all), Physics and Astronomy(all)
Source: Scopus
Source ID: 85012921190

Research output: Contribution to journalArticleScientificpeer-review

Behavior of the eigen form of hydronium at the air/water interface

Surface affinity of hydronium was explored using umbrella sampling molecular dynamics simulations with a refined polarizable potential. The polarizable interaction potential of H3O+ was reparametrized against accurate ab initio calculations for geometries including a water molecule approaching the Eigen cation from its oxygen side. Although there is no true hydrogenbonding with H3O+ acting as an acceptor, respecting in the force field the very shallow ab initio minimum corresponding to this interaction leads to a decrease in surface propensity of hydronium compared to previous results. Qualitatively, the mild surface affinity and strong surface orientation of hydronium is, nevertheless, robustly predicted by various computational approaches, as well as by spectroscopic experiments.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Computational Science X (CompX), Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, J. Heyrovský Institute of Physical Chemistry
Contributors: Jagoda-Cwiklik, B., Cwiklik, L., Jungwirth, P.
Number of pages: 6
Pages: 5881-5886
Publication date: 16 Jun 2011
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry A
Volume: 115
Issue number: 23
ISSN (Print): 1089-5639
Ratings: 
  • Scopus rating (2011): CiteScore 2.87 SJR 1.422 SNIP 1.131
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry
Source: Scopus
Source ID: 79959934455

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 6.34 SJR 1.758 SNIP 1.941
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

Influence of heat treatment on the abrasive wear resistance of a Cr3C2NiCr coating deposited by an ethene-fuelled HVOF spray process

This work reveals the influence of heat treatments on the microstructure, mechanical properties and abrasive wear behaviour of a Cr3C2NiCr coating deposited by an ethene-fuelled high-velocity oxygen-fuel spray process using an agglomerated-and-sintered feedstock powder. The wear resistance of an as-sprayed and heat treated (8 h at 800 °C) coating was evaluated in low- and high-stress abrasion regimes, the latter in a temperature range up to 800 °C. Precipitation of secondary carbides from the supersaturated as-sprayed binder matrix is at the core of the observed changes in the coatings wear resistance upon heat treating. This aging process renders the binder matrix softer and more ductile, as was probed by means of nanoindentation, and thereby improves its resistance against micro-cracking which is identified as an important wear mechanism in high-stress abrasion conditions.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Materials Science, AC2T Research GmbH, Fraunhofer Institut für Werkstoff- und Strahltechnik, Fraunhofer Institut für Keramische Technologien und Systeme
Contributors: Janka, L., Norpoth, J., Trache, R., Berger, L. M.
Number of pages: 8
Pages: 444-451
Publication date: 15 Apr 2016
Peer-reviewed: Yes

Publication information

Journal: Surface and Coatings Technology
Volume: 291
ISSN (Print): 0257-8972
Ratings: 
  • Scopus rating (2016): CiteScore 2.56 SJR 0.882 SNIP 1.379
Original language: English
ASJC Scopus subject areas: Chemistry(all), Condensed Matter Physics, Materials Chemistry, Surfaces, Coatings and Films, Surfaces and Interfaces
Keywords: Abrasion, CrC, Heat treatment, HVOF, Mechanical properties
Source: Scopus
Source ID: 84960192258

Research output: Contribution to journalArticleScientificpeer-review

Improving the high temperature abrasion resistance of thermally sprayed Cr3C2-NiCr coatings by WC addition

Two experimental agglomerated and sintered (a&s) feedstock powders were prepared, in order to reveal the role of WC addition on the microstructure, hardness, and the abrasion resistance of HVOF-sprayed Cr3C2-NiCr coatings. These powders contained 10 wt.% of sub-micron WC, 20 or 10 wt.% of nickel binder, and Cr3C2 as balance. Experimental coatings were deposited by a liquid fueled high velocity oxygen-fuel (HVOF) spray process and subsequently heat treated at 800 °C for 8 h to simulate elevated temperature service conditions. The microstructures of the powders and coatings were studied by SEM and X-ray diffraction, and the hardnesses of coatings were probed by means of micro and nanoindentation. In addition, the high stress abrasion resistance was tested in a temperature range from room temperature up to 800 °C. The microstructural characterization of the coatings displayed the presence of WC and tungsten containing Cr3C2 grains. The coating hardness increased after heat treatment, which stemmed from precipitation of secondary carbides and solid solution strengthening of the binder by tungsten. In addition, the study revealed that both experimental coatings have high wear resistance at room and elevated temperatures.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science, Research group: Surface Engineering, Viktor-Kaplan-Straße 2/C, Fraunhofer Institut für Keramische Technologien und Systeme, Fraunhofer Institut für Werkstoff- und Strahltechnik, Treibacher Industrie AG
Contributors: Janka, L., Berger, L. M., Norpoth, J., Trache, R., Thiele, S., Tomastik, C., Matikainen, V., Vuoristo, P.
Number of pages: 10
Pages: 296-305
Publication date: 15 Mar 2018
Peer-reviewed: Yes

Publication information

Journal: Surface and Coatings Technology
Volume: 337
ISSN (Print): 0257-8972
Ratings: 
  • Scopus rating (2018): CiteScore 3.44 SJR 0.973 SNIP 1.435
Original language: English
ASJC Scopus subject areas: Chemistry(all), Condensed Matter Physics, Surfaces and Interfaces, Surfaces, Coatings and Films, Materials Chemistry
Keywords: Abrasive wear, CrC-NiCr, Hardmetal, High temperature, Thermal spray, WC
Source: Scopus
Source ID: 85041378943

Research output: Contribution to journalArticleScientificpeer-review

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

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

General information

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

Publication information

Journal: Chemical Communications
Volume: 53
Issue number: 39
ISSN (Print): 1359-7345
Ratings: 
  • Scopus rating (2017): CiteScore 6.03 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 5.05 SJR 1.158 SNIP 1.458
Original language: English
ASJC Scopus subject areas: Analytical Chemistry, Filtration and Separation
Keywords: Ammonium bicarbonate precipitation, Electro-concentration, Nutrient recovery, Urine
Source: Scopus
Source ID: 85045218335

Research output: Contribution to journalArticleScientificpeer-review

Density functional study of structure and dynamics in liquid antimony and Sbn clusters

Density functional/molecular dynamics simulations have been performed on liquid antimony (588 atoms and six temperatures between 600 K and 1300 K) and on neutral Sb clusters with up to 14 atoms. We study structural patterns (coordination numbers, bond angles, and ring patterns, structure factors, pair distribution functions) and dynamical properties (vibration frequencies, diffusion constants, power spectra, dynamical structure factors, viscosity) and compare with available experimental results and with the results of our previous simulations on Bi. Three short covalent bonds characteristic of pnictogens are common in the clusters, and higher temperatures lead in the liquid to broader bond angle distributions, larger total cavity volumes, and weaker correlations between neighboring bond lengths. There are clear similarities between the properties of Sb and Bi aggregates.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Physics, Forschungszentrum Jülich (FZJ), Norwegian Univ. of Sci. and Technol., COMP Centre of Excellence, Department of Applied Physics, Aalto University, Aalto University
Contributors: Jones, R. O., Ahlstedt, O., Akola, J., Ropo, M.
Publication date: 21 May 2017
Peer-reviewed: Yes

Publication information

Journal: Journal of Chemical Physics
Volume: 146
Issue number: 19
Article number: 194502
ISSN (Print): 0021-9606
Ratings: 
  • Scopus rating (2017): CiteScore 2.5 SJR 1.252 SNIP 0.971
Original language: English
ASJC Scopus subject areas: Physics and Astronomy(all), Physical and Theoretical Chemistry
Source: Scopus
Source ID: 85029897404

Research output: Contribution to journalArticleScientificpeer-review

Reversible photodoping of TiO2 nanoparticles

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

General information

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

Publication information

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

Bibliographical note

INT=fot,"Joost, Urmas"

Research output: Contribution to journalArticleScientificpeer-review

Molekuly a ionty v pohybu: Počítačové simulace biochemických a biofyzikálních procesů

The review presents research activities aimed at better understanding of the effects of salt ions on biological processes (protein salting out/in, protein denaturation, enzymatic activity, processes in biological membranes, and radiation damage to DNA) using molecular simulations in close contact with the experiment.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Computational Science X (CompX), Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic
Contributors: Jungwirth, P.
Number of pages: 7
Pages: 278-284
Publication date: 2014
Peer-reviewed: Yes

Publication information

Journal: Chemicke Listy
Volume: 108
Issue number: 4
ISSN (Print): 0009-2770
Ratings: 
  • Scopus rating (2014): CiteScore 0.33 SJR 0.198 SNIP 0.504
Original language: Undefined/Unknown
ASJC Scopus subject areas: Chemistry(all)
Source: Scopus
Source ID: 84899732053

Research output: Contribution to journalArticleScientificpeer-review

Double-side pumped membrane external-cavity surface-emitting laser (MECSEL) with increased efficiency emitting > 3 W in the 780 nm region

We demonstrate a double-side pumped MECSEL emitting more than 3 W of output power in the 780 nm wavelength region. The laser exhibits an efficiency as high as 34.4 %.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Physics
Contributors: Kahle, H., Phung, H., Penttinen, J., Rajala, P., Tukiainen, A., Ranta, S., Guina, M.
Publication date: 1 May 2019

Host publication information

Title of host publication: 2019 Conference on Lasers and Electro-Optics, CLEO 2019 - Proceedings
Publisher: IEEE
ISBN (Electronic): 9781943580576
ASJC Scopus subject areas: Spectroscopy, Industrial and Manufacturing Engineering, Safety, Risk, Reliability and Quality, Management, Monitoring, Policy and Law, Electronic, Optical and Magnetic Materials, Radiology Nuclear Medicine and imaging, Instrumentation, Atomic and Molecular Physics, and Optics

Bibliographical note

INT=phys,"Rajala, Patrik"

Source: Scopus
Source ID: 85069191246

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

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

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

General information

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

Publication information

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

Research output: Contribution to journalArticleScientificpeer-review

How conformational flexibility stabilizes the hyperthermophilic elongation factor G-domain

Proteins from thermophilic organisms are stable and functional well above ambient temperature. Understanding the molecular mechanism underlying such a resistance is of crucial interest for many technological applications. For some time, thermal stability has been assumed to correlate with high mechanical rigidity of the protein matrix. In this work we address this common belief by carefully studying a pair of homologous G-domain proteins, with their melting temperatures differing by 40 K. To probe the thermal-stability content of the two proteins we use extensive simulations covering the microsecond time range and employ several different indicators to assess the salient features of the conformational landscape and the role of internal fluctuations at ambient condition. At the atomistic level, while the magnitude of fluctuations is comparable, the distribution of flexible and rigid stretches of amino-acids is more regular in the thermophilic protein causing a cage-like correlation of amplitudes along the sequence. This caging effect is suggested to favor stability at high T by confining the mechanical excitations. Moreover, it is found that the thermophilic protein, when folded, visits a higher number of conformational substates than the mesophilic homologue. The entropy associated with the occupation of the different substates and the thermal resilience of the protein intrinsic compressibility provide a qualitative insight on the thermal stability of the thermophilic protein as compared to its mesophilic homologue. Our findings potentially open the route to new strategies in the design of thermostable proteins.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Multi-scaled biodata analysis and modelling (MultiBAM), Laboratoire de Biochimie Théorique, Université Paris Diderot, Centro S3
Contributors: Kalimeri, M., Rahaman, O., Melchionna, S., Sterpone, F.
Number of pages: 11
Pages: 13775-13785
Publication date: 7 Nov 2013
Peer-reviewed: Yes

Publication information

Journal: Journal of Physical Chemistry Part B
Volume: 117
Issue number: 44
ISSN (Print): 1520-6106
Ratings: 
  • Scopus rating (2013): CiteScore 3.53 SJR 1.504 SNIP 1.194
Original language: English
ASJC Scopus subject areas: Physical and Theoretical Chemistry, Materials Chemistry, Surfaces, Coatings and Films

Bibliographical note

EXT="Kalimeri, Maria"

Source: Scopus
Source ID: 84887752230

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 1.28 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

Effect of nitro groups and alkyl chain length on the negative ion tandem mass spectra of alkyl 3-hydroxy-5-(4'-nitrophenoxy) and alkyl 3-hydroxy-5-(2', 4'-dinitrophenoxy) benzoates

Tandem mass spectrometric behaviour was studied for a small combinatorial library of alkyl 3-hydroxy-5(4'-nitrophenoxy) benzoates (A1-A5) and alkyl 3-hydroxy-5-(2', 4'-dinitrophenoxy) benzoates (B1-B5). The spectra were recorded by negative ion electrospray low-energy collision induced dissociation (CID) tandem mass spectrometry. The product ion spectra of [M - H]- of the benzoates A1-A5 are similar, as are those of benzoates B1-B5. However, the spectra of the B series compounds differ significantly from those of the A series owing to the second electron-withdrawing nitro substituent in the B compounds. In addition, the length of the alkyl chain has an effect on the fragmentation. However, both series of compounds exhibit an abundant nitrophenoxy ion formed by the loss of 3-hydroxybenzoate. This is at m/z 138 in A1-A5 and at m/z 183 in B1-B5. A precursor ion scan of the nitrophenoxy ion provides a rapid method to identify the synthesised compounds in this type of combinatorial mixture.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Division of Pharmaceutical Chemistry, University of Helsinki, Department of Pharmacy
Contributors: Kangas, H., Franzén, R., Tois, J., Taskinen, J., Kostiainen, R.
Number of pages: 5
Pages: 1680-1684
Publication date: 1999
Peer-reviewed: Yes

Publication information

Journal: Rapid Communications in Mass Spectrometry
Volume: 13
Issue number: 16
ISSN (Print): 0951-4198
Ratings: 
  • Scopus rating (1999): SJR 1.379 SNIP 1.096
Original language: English
ASJC Scopus subject areas: Analytical Chemistry, Spectroscopy
Source: Scopus
Source ID: 0032814434

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 3.42 SJR 0.947 SNIP 0.834
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Chemistry(all)
Electronic versions: