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  • 201.
    EL Andaloussi, Samir
    et al.
    Stockholm University, Faculty of Science, Department of Neurochemistry.
    Lehto, Taavi
    Laboratory of Molecular Biotechnology, Institute of Technology, Tartu University, Tartu, Estonia.
    Lundin, Per
    Stockholm University, Faculty of Science, Department of Neurochemistry.
    Langel, Ülo
    Stockholm University, Faculty of Science, Department of Neurochemistry.
    Application of PepFect peptides for the delivery of splice-correcting oligonucleotides2011In: Cell-penetrating peptides: Methods and Protocols, New York: Humana Press, 2011, p. 361-373Chapter in book (Other academic)
    Abstract [en]

    One oligonucleotide-based approach that appear very promising for the treatment of different genetic disorders are based on so-called splice-correcting oligonucleotides (SCOs) that are exploited to manipulate splicing patterns. In order to increase the bioavailability, cell-penetrating peptides (CPPs) have readily been covalently conjugated to SCOs to facilitate cellular internalization. While being a successful strategy for the delivery of uncharged oligonucleotides (ONs), it is extremely difficult to generate covalent conjugates between commonly used negatively charged ON analogs and cationic CPPs. Furthermore, high concentrations of ONs in the micromolar range are often needed to obtain biological responses, most likely as a result of endosomal entrapment of material. Therefore, exploring other vectorization methods using CPPs with endosomolytic properties are highly desired. A method of using stearyl modified CPP (i.e., TP10) analogs, named PepFect3 and PepFect4, are being described for the transfection of antisense SCOs using a simple one-step co-incubation procedure. These peptides form complexes with SCOs and efficiently promote cellular uptake by facilitating endosomal escape. This chapter describes the methods of how to form and characterize these nanoparticles and the cellular assay used to address the delivery.

  • 202.
    EL Andaloussi, Samir
    et al.
    Stockholm University, Faculty of Science, Department of Neurochemistry.
    Said Hassane, Fatouma
    Université Montpellier, Motpellier, France.
    Boisguerin, Prisca
    Université Montpellier, Motpellier, France.
    Sillard, Rannar
    University of Tartu, Institute of Technology, Tartu, Estonia.
    Langel, Ülo
    Stockholm University, Faculty of Science, Department of Neurochemistry.
    Lebleu, Bernard
    Université Montpellier, Motpellier, France.
    Cell-penetrating peptides-based strategies for the delivery of splice redirecting antisense oligonucleotides2011In: Therapeutic Oligonucleotides: Methods and Protocols / [ed] John Goodchild, New York: Humana Press, 2011, p. 75-89Chapter in book (Other academic)
    Abstract [en]

    Progress in our understanding of the molecular pathogenesis of human malignancies has provided therapeutic targets amenable to oligonucleotide (ON)-based strategies. Antisense ON-mediated splicing regulation in particular offers promising prospects since the majority of human genes undergo alternative splicing and since splicing defects have been found in many diseases. However, their implementation has been hampered so far by the poor bioavailability of nucleic acids-based drugs. Cell-penetrating peptides (CPPs) now appear as promising non-viral delivery vector for non-permeant biomolecules. We describe here new CPPs allowing the delivery of splice redirecting steric-block ON using either chemical conjugation or non-covalent complexation. We also describe a convenient and robust splice redirecting assay which allows the quantitative assessment of ON nuclear delivery.

  • 203. Elbourne, Aaron
    et al.
    Sweeney, James
    Webber, Grant B.
    Wanless, Erica J.
    Warr, Gregory G.
    Rutland, Mark W.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Atkin, Rob
    Adsorbed and near-surface structure of ionic liquids determines nanoscale friction2013In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 49, no 60, p. 6797-6799Article in journal (Refereed)
    Abstract [en]

    Surface-adsorbed and near-surface ion layer structure controls nanotribology in the silica-propylammonium nitrate (PAN)-mica system. Atomic Force Microscopy (AFM) imaging and normal force curves reveal that the normal load dictates the number of interfacial ion layers and the lateral layer structure. Shear force measurements show the lubricity of the interface changes with the number, and lateral structure, of the confined ion layer(s).

  • 204.
    Elmgren, Maja
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Ho, Felix M.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Åkesson, Eva
    Uppsala University, University Administration.
    Schmid, Siegbert
    University of Sydney, School of Chemistry.
    Towns, Marcy
    Purdue University, Department of Chemistry.
    Comparison and Evaluation of Learning Outcomes from an International Perspective: Development of a Best-Practice Process2015In: Journal of Chemical Education, ISSN 0021-9584, E-ISSN 1938-1328, Vol. 92, no 3, p. 427-432Article in journal (Refereed)
    Abstract [en]

    Chemistry education focused on learning outcomes is increasingly practiced, providing new opportunities for international comparisons. The interest in intended learning outcomes and constructive alignment has grown in many parts of the world due to both research in higher education and political decisions. In an International Union of Pure and Applied Chemistry (IUPAC) project, we have developed a method of using critical evaluation of learning outcomes and descriptors at international, national, and institutional levels to enhance learner-centered chemistry education. This method is process-focused, aimed at learning by sharing and comparing practices around the world. Three overarching documents for the chemistry bachelor from the USA, Europe and Australia were compared. The differences were found to be more in style than in content. A tool for self-analysis was constructed to evaluate how learning outcomes for courses and modules are linked to each other and to learning outcomes for educational programs and how the expected learning outcomes can be aligned with learning activities and assessment. We conclude that the method can be used to elucidate the correspondence between learning outcomes at different levels, and the constructive alignment between learning outcomes, learning activities and assessment. The process gives new perspectives and shared knowledge. Chemistry education may need to be different depending on local considerations, and awareness of these differences is of value for further development.

  • 205. Emam, A. N.
    et al.
    Mohamed, M. B.
    Girgis, E.
    Rao, K. Venkat
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Hybrid magnetic-plasmonic nanocomposite: Embedding cobalt clusters in gold nanorods2015In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 44, p. 34696-34703Article in journal (Refereed)
    Abstract [en]

    We developed a method to fabricate hybrid magnetic-plasmonic nanorods (Au-Co NRs) via a modified seed mediated method. The only modification is to use cobalt ions instead of Au3+ in the preparation of the seed solution to obtain gold nanorods doped with Co clusters. By adjusting the amount of cobalt seed solution, Au-Co NRs of controlled aspect ratio can be obtained. The optical properties of the obtained Au-Co NRs were investigated and compared to those of the pure Au NRs. A slight shift and broadening were observed in the alloys compared to the pure ones, which was attributed to the presence of Co clusters leading to suppression of the dielectric properties. High resolution transmission electron microscopy (HRTEM) images indicate the existence of Co clusters in situ in the Au NR host and clearly show the metal-metal interface. The magnetic properties of the obtained Au-Co NRs increase as the concentration of dopant Co cluster seeds increases, as investigated by vibrating sample magnetometry (VSM). Our approach allows us to design nanomaterials of controlled shape, optical and magnetic properties which have many promising applications in tharanostics and photoelectronics.

  • 206. Emanuelsson, Rikard
    et al.
    Löfås, Henrik
    Wallner, Andreas
    Nauroozi, Djawed
    Baumgartner, Judith
    Marschner, Christoph
    Ahuja, Rajeev
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics. Uppsala University, Sweden.
    Ott, Sascha
    Grigoriev, Anton
    Ottosson, Henrik
    Configuration- and Conformation-Dependent Electronic-Structure Variations in 1,4-Disubstituted Cyclohexanes Enabled by a Carbon-to-Silicon Exchange2014In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 20, no 30, p. 9304-9311Article in journal (Refereed)
    Abstract [en]

    Cyclohexane, with its well-defined conformers, could be an ideal force-controlled molecular switch if it were to display substantial differences in electronic and optical properties between its conformers. We utilize sigma conjugation in heavier analogues of cyclohexanes (i.e. cyclohexasilanes) and show that 1,4-disubstituted cyclohexasilanes display configuration-and conformation-dependent variations in these properties. Cis- and trans-1,4-bis(trimethylsilylethynyl)-cyclohexasilanes display a 0.11 V difference in their oxidation potentials (computed 0.11 V) and a 0.34 eV difference in their lowest UV absorption (computed difference between first excitations 0.07 eV). This is in stark contrast to differences in the corresponding properties of analogous all-carbon cyclohexanes (computed 0.02 V and 0.03 eV, respectively). Moreover, the two chair conformers of the cyclohexasilane trans isomer display large differences in electronic-structure-related properties. This enables computational design of a mechanically force-controlled conductance switch with a calculated single-molecule ON/OFF ratio of 213 at zero-bias voltage.

  • 207.
    Engdahl, Cecilia
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Knutsson, Sofie
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Fredriksson, Sten-Åke
    Linusson, Anna
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bucht, Göran
    Ekström, Fredrik
    Acetylcholinesterases from the Disease Vectors Aedes aegypti and Anopheles gambiae: Functional Characterization and Comparisons with Vertebrate Orthologues2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 10, article id e0138598Article in journal (Refereed)
    Abstract [en]

    Mosquitoes of the Anopheles (An.) and Aedes (Ae.) genus are principal vectors of human diseases including malaria, dengue and yellow fever. Insecticide-based vector control is an established and important way of preventing transmission of such infections. Currently used insecticides can efficiently control mosquito populations, but there are growing concerns about emerging resistance, off-target toxicity and their ability to alter ecosystems. A potential target for the development of insecticides with reduced off-target toxicity is the cholinergic enzyme acetylcholinesterase (AChE). Herein, we report cloning, baculoviral expression and functional characterization of the wild-type AChE genes (ace-1) from An. gambiae and Ae. aegypti, including a naturally occurring insecticide-resistant (G119S) mutant of An. gambiae. Using enzymatic digestion and liquid chromatography-tandem mass spectrometry we found that the secreted proteins were post-translationally modified. The Michaelis-Menten constants and turnover numbers of the mosquito enzymes were lower than those of the orthologous AChEs from Mus musculus and Homo sapiens. We also found that the G119S substitution reduced the turnover rate of substrates and the potency of selected covalent inhibitors. Furthermore, non-covalent inhibitors were less sensitive to the G119S substitution and differentiate the mosquito enzymes from corresponding vertebrate enzymes. Our findings indicate that it may be possible to develop selective non-covalent inhibitors that effectively target both the wild-type and insecticide resistant mutants of mosquito AChE.

  • 208.
    ENMYREN, CAROLINE
    KTH, School of Chemical Science and Engineering (CHE).
    Syntes av betulinderivat och deras applikation som mjukgörare för PVC2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Betulin is an easily extractable substance that is found in high concentrations in the bark of birch trees. As bark is a by-product that is generated in thousands of tonnes every year in pulp and paper mills, it would be of both economic and environmental gain to utilize its possible extractives. Betulin has currently found application as an additive in skin care products, but is as of yet not considered a large scale industrial resource.

    In this project betulin was used as a starting material to synthesize mono- and di-substituted betulin derivatives via esterification of the hydroxyl groups with propionyl chloride, isopropionyl chloride, 2- chloropropionyl chloride, 3-chloropropionyl chloride, nonanoyl chloride, palmitoyl chloride, trimethyl acetyl chloride and methacrylic anhydride. The structures of the products were confirmed with FT-IR and 1H-NMR. The products’ potential as plasticizers for poly (vinyl chloride) (PVC) was evaluated theoretically with the Hansen Solubility Parameter and practically via solvent casting with PVC and determination of the glass transition temperature with differential scanning calorimetry (DSC). It was found that most of the derivatives appeared to be soluble in PVC at 10-30wt% but appeared to induce only minor effects on the thermal properties when compared to pure PVC films.

  • 209.
    Eriksson, Jonas
    Stockholm University, Faculty of Science, Department of Neurochemistry.
    Gene therapy tools: oligonucleotides and peptides2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Genetic mutations can cause a wide range of diseases, e.g. cancer. Gene therapy has the potential to alleviate or even cure these diseases. One of the many gene therapies developed so far is RNA-cleaving deoxyribozymes, short DNA oligonucleotides that specifically bind to and cleave RNA. Since the development of these synthetic catalytic oligonucleotides, the main way of determining their cleavage kinetics has been through the use of a laborious and error prone gel assay to quantify substrate and product at different time-points. We have developed two new methods for this purpose. The first one includes a fluorescent intercalating dye, PicoGreen, which has an increased fluorescence upon binding double-stranded oligonucleotides; during the course of the reaction the fluorescence intensity will decrease as the RNA is cleaved and dissociates from the deoxyribozyme. A second method was developed based on the common denominator of all nucleases, each cleavage event exposes a single phosphate of the oligonucleotide phosphate backbone; the exposed phosphate can simultaneously be released by a phosphatase and directly quantified by a fluorescent phosphate sensor. This method allows for multiple turnover kinetics of diverse types of nucleases, including deoxyribozymes and protein nucleases.

    The main challenge of gene therapy is often the delivery into the cell. To bypass cellular defenses researchers have used a vast number of methods; one of these are cell-penetrating peptides which can be either covalently coupled to or non-covalently complexed with a cargo to deliver it into a cell. To further evolve cell-penetrating peptides and understand how they work we developed an assay to be able to quickly screen different conditions in a high-throughput manner. A luciferase up- and downregulation experiment was used together with a reduction of the experimental time by 1 day, upscaling from 24- to 96-well plates and the cost was reduced by 95% compared to commercially available assays. In the last paper we evaluated if cell-penetrating peptides could be used to improve the uptake of an LNA oligonucleotide mimic of GRN163L, a telomerase-inhibiting oligonucleotide. The combination of cell-penetrating peptides and our mimic oligonucleotide lead to an IC50 more than 20 times lower than that of GRN163L.

  • 210.
    Eriksson, Ulrika
    Örebro University, School of Science and Technology.
    Contribution of polyfluoroalkyl phosphate esters (PAPs) and other precursor compounds to perfluoroalkyl carboxylates (PFCAs) in humans and the environment2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Per-and polyfluoroalkyl substances (PFAS) are anthropogenic compounds that have been spread all over the world. The use of fluorotelomer compounds, short-chained homologues, and other PFASs with perfluorinated moieties has emerged recent years. One of these emerging compound classes is polyfluoroalkyl phosphate esters (PAPs), which have the ability to degrade into persistent PFCAs.

    The aim of this thesis was to assess the contribution of PAPs and other precursors to the exposure of PFCAs to humans and the environment. The main objective was to analyze a wide range of PFAS in human serum, wild bird eggs, indoor dust, waste water, and sludge. There was a significant contribution from selected precursors to the total amount of PFASs in the abiotic compartments indoor dust, waste water, and sludge. Levels of PAPs found in house dust exceeded those of PFCAs and perfluorosulfonic acids (PFSAs), revealing PAPs as a world-wide important exposure source.

    A net increase was during waste water treatment was observed for several PFASs in Swedish waste water treatment plants. Together with presence of precursor compounds and intermediates in the influent water and the sludge, this suggest that degradation of PFCA precursors contributed to the increase of PFCAs. Detection of precursors in human serum, together with slow declining trends of PFCAs, revealed an ongoing exposure of PFCAs to the general population of Australia. The diPAPs and the FTSAs were also detected in raptor bird eggs from Sweden from both the terrestrial and the freshwater environment. The precursors concentrations and patterns observed reveal that current regulatory measures are insufficient for the purpose of protecting humans and the environment from PFASs exposure.

  • 211.
    Eriksson, Ulrika
    et al.
    Örebro University, School of Science and Technology.
    Haglund, Peter
    Umeå University, Umeå, Sweden.
    Kärrman, Anna
    Örebro University, School of Science and Technology.
    Contribution of precursor compounds to the release of per- and polyfluoroalkyl substances (PFASs) from waste water treatment plants (WWTPs)Manuscript (preprint) (Other academic)
  • 212.
    Eriksson, Ulrika
    et al.
    Örebro University, School of Science and Technology.
    Mueller, Jochen F.
    University of Queensland, Coopers Plains, Australia.
    Toms, Leisa-Maree L.
    Queensland University of Technology, Kelvin Grove, Australia .
    Hobson, Peter
    Sullivan and Nicolaides Pathology, Taringa, Australia.
    Kärrman, Anna
    Örebro University, School of Science and Technology.
    Temporal trends of PFSAs, PFCAs and selected precursors in Australian serum from 2002 to 2013Manuscript (preprint) (Other academic)
  • 213. Eshagh, Mehdi
    et al.
    Bagherbandi, Mohammad
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geoinformatik och Geodesi.
    Smoothing impact of isostatic crustal thickness models on local integral inversion of satellite gravity gradiometry data2011In: ACTA GEOPHYSICA, ISSN 1895-6572, Vol. 59, no 5, p. 891-906Article in journal (Refereed)
    Abstract [en]

    The effects of topographic masses on satellite gradiometric data are large and in order to reduce the magnitude of these effects some compensation mechanisms should be considered. Here we use the isostatic hypotheses of Airy-Heiskanen and the recent Vening Meinesz-Moritz for compensating these effects and to smooth the data prior to their downward continuation to gravity anomaly. The second-order partial derivatives of extended Stokes' formula are used for the continuations over a topographically rough territory like Persia. The inversions are performed and compared based on two schemes of the remove-compute-restore technique and direct downward continuation. Numerical results show that the topographic-isostatic effect based on Vening Meinesz-Mortiz's hypothesis smoothes the data better than that based on Airy-Heiskanen's hypothesis. Also the quality of inversions of the smoothed data by this mechanism is twice better than that of the nonsmoothed ones.

  • 214. Esmaily, M.
    et al.
    Blücher, D. B.
    Wreland Lindström, Rakel
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Svensson, J. -E
    Johansson, L. G.
    The influence of SO2 on the corrosion of Mg and Mg-Al alloys2015In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 162, no 6, p. C260-C269Article in journal (Refereed)
    Abstract [en]

    The SO2-induced atmospheric corrosion of some magnesium-aluminum (Mg-Al) alloys, including Mg alloy AZ91D, and commercially pure Mg (CP Mg) was investigated using well-controlled laboratory exposures and included real-time measurements of SO2 deposition. The influence of SO2 concentration, alloy composition, humidity, and ppb level additions of O-3 or NO2 on the rate of SO2 deposition was investigated. SO2 accelerates the corrosion of Mg and Mg alloys causing localized corrosion, MgSO(3)6H(2)O being the dominant corrosion product. At 60% RH, traces of O-3 or NO2 strongly increased both the SO2 deposition and the corrosion rate. The rate of SO2 deposition was strongly dependent on humidity; at 70% RH and higher the SO2 deposition rate was very rapid and constant in time while it was transient below 50% RH. At 60% RH, a change from transient to rapid, steady-state, SO2 deposition occurred. The sudden activation is explained by the onset of electrochemical corrosion. The activation behavior was shown to depend on SO2 concentration, the thickness of the surface film and by the presence of ambient O-2. (C) The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited.

  • 215.
    Espling, Maria
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Copper-transporting proteins and their interactions with platinum-based anticancer substances2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

      Cisplatin (CisPt) is an important drug that is used against various cancers, including testicular, ovarian, lung, head, and neck cancer. However, its effects are limited by cellular resistance. The resistance is believed to be multifactorial, and may be mediated to varying degree by multiple systems in cells, one of the proposed systems being the copper (Cu) transporting system. The Cu-importer Ctr1 has proven importance for cellular sensitivity to CisPt by regulating its influx, while the Golgi-localized Cu-ATP:ases ATP7A/B can putatively mediate CisPt efflux and/or drug sequestration. Atox1 is a small Cu-chaperone that normally transfers Cu between Ctr1 and ATP7A/B, prior to delivery of Cu to the proteins in the secretory pathway. Since Ctr1 and ATP7A/B are reportedly involved in CisPt-resistance, CisPt interaction with Atox1 was the focus of the project this thesis is based upon.

      Using a variety of techniques, Atox1 was found to bind CisPt, also simultaneously with Cu. The Atox1-CisPt complexes were further probed using selected mutants in studies demonstrating that only the two cysteines (Cys12 and Cys15) in the Cu-binding site of Atox1 are essential for CisPt interactions. A proposed Atox1 di-metal complex containing both Cu and CisPt was found to be monomeric, and no loss of Cu was observed. In vitro experiments demonstrated that CisPt could also bind to metal-binding domain 4 of ATP7B (WD4), and that the drug could be transferred from Atox1 to the domain. These findings indicated that Atox1 may transfer CisPt to ATP7A/B in vivo, utilizing the same transport pathway as Cu. However, the CisPt-bound Atox1 complexes were not stable over time; upon incubation, protein unfolding and aggregation were observed. Thus, in vivo, Atox1 might alternatively be a dead-end sink for CisPt.

      The effects of the ligands around the Pt-center of Pt-based anticancer drugs and drug derivatives on Atox1 binding and unfolding were also investigated. The ligands’ chemistry and geometry were shown to dictate the extent and rate of the Pt-based substances interactions with Atox1. Finally, the occurrence of Atox1-CisPt interactions in a biological environment was demonstrated by developing and applying an antibody-based method allowing analysis of metals associated with Atox1 extracted from CisPt-treated cells.

      The findings presented in this thesis show that CisPt binds to Atox1 and WD4, also simultaneously with Cu, in vitro. The results support the hypothesis that Cu-transporting proteins can mediate cellular resistance to CisPt in vivo, and provide a deeper chemical understanding of the interactions between the proteins and the drug.

  • 216.
    Falk, Adrian
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Bengtsson, Emmy
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Juhlin, Stina
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Le, Dong
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Niklasson, Lovisa
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Svensson, Karolina
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Tesfamhret, Yonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Utveckling av flödesreaktor: Ett sammarbetesprojekt mellan fakulteten för teknik och naturvetenskap vid Uppsala Universitet och Fagrell produktutveckling AB2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

     This report deals with the

    collaborative project between Fagrell

    Produkt Utveckling AB and students

    from the Faculty of Science and

    Technology at Uppsala University. The

    overall objective of the project was

    in addition to developing students'

    abilities, to help Fagrell with

    verification and development of

    Fagrells prototype, Fundamental flow

    reactor, for flow chemistry. The

    uniqueness of Fagrells flow reactor is

    that it should be simple and

    affordable compared to competing flow

    reactors in the market.

    The verification was done by

    laboratory and simulation sessions.

    The verification shows that Fagrells

    idea on how to construct a flow

    reactor is very good.

    The development included both

    technology and business. The result of

    developments can be helpful for the

    commercialization of Fagrell flow

    reactor.

  • 217.
    Fall, Andreas B.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Lindström, Stefan B.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Sprakel, Joris
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    A physical cross-linking process of cellulose nanofibril gels with shear-controlled fibril orientation2013In: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 9, no 6, p. 1852-1863Article in journal (Refereed)
    Abstract [en]

    Cellulose nanofibrils constitute the smallest fibrous components of wood, with a width of approximately 4 nm and a length in the micrometer range. They consist of aligned linear cellulose chains with crystallinity exceeding 60%, rendering stiff, high-aspect-ratio rods. These properties are advantageous in the reinforcement components of composites. Cross-linked networks of fibrils can be used as templates into which a polymer enters. In the semi-concentrated regime (i.e. slightly above the overlap concentration), carboxy methylated fibrils dispersed in water have been physically cross-linked to form a volume-spanning network (a gel) by reducing the pH or adding salt, which diminishes the electrostatic repulsion between fibrils. By applying shear during or after this gelation process, we can orient the fibrils in a preferred direction within the gel, for the purpose of fully utilizing the high stiffness and strength of the fibrils as reinforcement components. Using these gels as templates enables precise control of the spatial distribution and orientation of the dispersed phase of the composites, optimizing the potentially very large reinforcement capacity of the nanofibrils.

  • 218.
    Femenia, Marc
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Corrosion Studies of Duplex Stainless Steels with Micrometer Resolution2004In: Journal of Corrosion Science & Engineering, ISSN 1466-8858, E-ISSN 1466-8858, Vol. 6, p. paper 28-Article in journal (Refereed)
    Abstract [en]

    The local corrosion behavior of duplex stainless steel (DSS) is affected by a wide variety of factors. Localized corrosion of DSS frequently starts at micrometer scale inclusions or precipitates, which are often segregated in the austenite-ferrite boundary regions. Moreover, due to the partitioning of the key alloying elements of ferrite (Cr and Mo) and austenite (N and Ni), the local interactions between the phases must also be considered. The aim of this doctoral study was to increase the knowledge about the local dissolution behavior of DSS in acidic-chloride environments. The recent developments of new local probing techniques have opened a new frontier in corrosion science, providing valuable local information not accessible in the past. The local techniques used include electrochemical scanning tunneling microscopy (EC-STM), scanning probe force microscopy (SKPFM), magnetic force microscopy (MFM), and scanning Auger electron Spectroscopy (SAES), all with micrometer or sub-micrometer resolution. With EC-STM, it was possible to monitor local dissolution processes on DSS in situ, and in real time. MFM was capable of imaging the phase distribution in DSS without the need of the traditional surface etching, while SKPFM revealed that the Volta potential difference between the two phases was measurable and significant. SAES showed that the composition gradient at the phase boundaries is narrower than 2 µm. Different types of DSSs have been studied, from low-alloyed DSS to superduplex. Higher contents of Cr, Mo and N strengthened both phases as well as the phase boundaries, resulting in phases having similar corrosion resistance that showed a more uniform dissolution behavior. However, the Volta potential difference between the phases proved to be of the same order for all the DSSs studied. Austenite was in general associated to regions displaying a more noble Volta potential than ferrite, resulting in a higher dissolution rate of the ferrite next to the austenite phase.

  • 219.
    Feng, Wenting
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Klaminder, Jonatan
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Boily, Jean-Francois
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Thermal Stability of Goethite-Bound Natural Organic Matter Is Impacted by Carbon Loading2015In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 119, no 51, p. 12790-12796Article in journal (Refereed)
    Abstract [en]

    Dissolved natural organic matter (NOM) sorption at mineral surfaces can significantly affect the persistence. of organic carbon in soils and sediments. Consequently, determining the mechanisms that stabilize sorbed NOM is crucial for predicting the persistence of carbon in nature. This study determined the effects of loadings and pH on the thermal stability of NOM associated: With synthetic goethite (alpha-FeOOH) particle surfaces, as a proxy for NOM mineral interactions taking place in nature.. NOM thermal stability was investigated using temperature programmed desorption (TPD) in the 30-700 degrees C range to collect vibration spectra of thermally decomposing goethite NOM assemblages, and to concomitantly analyze evolved gases using mass spectrometry Results showed that NOM thermal stability, indicated by the range of temperatures in which CO2 evolved during thermal decomposition, was greatest in unbound NOM and lowest when NOM was bound to goethite. NOM thermal Stability was also loading dependent. It decreased:when loadings were in increased the 0.01 to 042 mg C m(-2) range, where the upper value corresponds to a Langmuirian adsorption maximum. Concomitant Fourier transform infrared (FTIR) spectroscopy measurement showed that these lowered stabilities could be ascribed to direct NOM-goethite interactions that dominated the NOM binding environment. Mineral surface interactions at larger loadings involved, on the contrary, a smaller fraction of the sorbed NOM, thus increasing thermal stability toward that of its unbound counterpart. This study thus identifies a sorption threshold below which NOM sorption to goethite decreases NOM thermal stability, and above which no strong effects are Manifested. This should likely influence the fate of organic carbon exposed to thermal gradients in natural environments.

  • 220.
    Fernandes, Ricardo Madeira F.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. University of Porto, Portugal.
    Buzaglo, M.
    Regev, O.
    Furó, I.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Marques, E. F.
    Mechanical agitation induces counterintuitive aggregation of pre-dispersed carbon nanotubes2017In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 493, p. 398-404Article in journal (Refereed)
    Abstract [en]

    Mechanical agitation is commonly used to fragment and disperse insoluble materials in liquids. However, here we show that when pristine single-walled carbon nanotubes pre-dispersed in water are subject to vortex-shaking for very short periods (typically 10–60 s, power density ∼0.002 W mL−1), re-aggregation counterintuitively occurs. The initial dispersions are produced using surfactants as dispersants and powerful tip sonication (∼1 W mL−1) followed by centrifugation. Detailed imaging by light and electron microscopies shows that the vortex-induced aggregates consist of loose networks (1–102 μm in size) of intertwined tubes and thin bundles. The average aggregate size increases with vortexing time in an apparently logarithmic manner and depends on the dispersant used, initial concentration of nanotubes and size distribution of bundles. The aggregation is, nonetheless, reversible: if the vortex-shaken dispersions are mildly bath-sonicated (∼0.03 W mL−1), the flocs break down and re-dispersal occurs. Molecular insight for the mechanism behind this surprising phenomenon is put forth.

  • 221.
    Ferraris, M.
    et al.
    Politecnico di Torino, Italy.
    Perero, S.
    Politecnico di Torino, Italy.
    Ferraris, S.
    Politecnico di Torino, Italy.
    Miola, M.
    Politecnico di Torino, Italy.
    Vernè, E.
    Politecnico di Torino, Italy.
    Skoglund, S.
    KTH Royal Institute of Technology, Sweden.
    Blomberg, Eva
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry, Materials and Surfaces. KTH Royal Institute of Technology, Sweden.
    Odnevall Wallinder, I.
    KTH Royal Institute of Technology, Sweden.
    Antibacterial silver nanocluster/silica composite coatings on stainless steel2017In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 396, p. 1546-1555Article in journal (Refereed)
    Abstract [en]

    A coating made of silver nanocluster/silica composites has been deposited, via a radio frequency (RF) co-sputtering technique, for the first time onto stainless steel (AISI 304L) with the aim to improve its antibacterial properties. Different thermal treatments after coating deposition have been applied in order to optimize the coating adhesion, cohesion and its antibacterial properties. Its applicability has been investigated at realistic conditions in a cheese production plant. The physico-chemical characteristics of the coatings have been analyzed by means of different bulk and surface analytical techniques. Field emission scanning electron microscopy (FESEM), X-ray Photoelectron Spectroscopy (XPS), contact angle measurements and atomic force microscopy (AFM) were employed to assess coating morphology, composition, surface roughness, wetting properties, size and local distribution of the nanoparticles within the coating. Tape tests were used to determine the adhesion/cohesion properties of the coating. The amount and time-dependence of released silver in solutions of acetic acid, artificial water, artificial tap water and artificial milk were determined by means of Atomic Absorption Spectroscopy (AAS). The antibacterial effect of the coating was evaluated at different experimental conditions using a standard bacterial strain of Staphylococcus aureus in compliance with National Committee for Clinical Laboratory Standards (NCCLS) and AATCC 147 standards. The Ahearn test was performed to measure the adhesion of bacteria to the coated stainless steel surface compared with a control surface. The antibacterial coating retained its antibacterial activity after thermal treatment up to 450 °C and after soaking in common cleaning products for stainless steel surfaces used for e.g. food applications. The antibacterial capacity of the coating remained at high levels for 1-5 days, and showed a good capacity to reduce the adhesion of bacteria up to 30 days. Only a few percent of silver in the coating was released into acetic acid, even after 10 days of exposure at 40 °C. Most silver (> 90%) remained also in the coating even after 240 h of continuous exposure. Similar observations were made after repeated exposure at 100 °C. Very low levels of released silver in solution were observed in artificial milk. No release of silver nanoparticles was observed either in synthetic tap water or in artificial milk at given conditions. The coating further displayed good antibacterial properties also when tested during working conditions in a cheese production plant.

  • 222.
    Ferro, Lorenza
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gentili, Francesco G.
    Funk, Christiane
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Isolation and characterization of microalgal strains for biomass production and wastewater reclamation in Northern Sweden2018In: Algal Research, ISSN 2211-9264, Vol. 32, p. 44-53Article in journal (Refereed)
    Abstract [en]

    Microalgal strains adapted to the harsh Nordic climate were isolated from Swedish fresh- and wastewater sources and tested for their ability to grow in municipal wastewater. The 62 strains able to grow in municipal wastewater belonged to 12 different genera, of those DesmodesmusScenedesmus and Chlorella were most representative. Eight axenic strains were further characterized, all of which could efficiently remove nitrogen (>90%) and phosphate (>99%) from the wastewater in less than two weeks. The microalga Coelastrellasp. had the highest performance in terms of both biomass concentration and total lipid content (1.46 g/L, 30.8%) after 13 days of cultivation. This is the first report of a Coelastrellastrain isolated in Sweden. Even Chlorella vulgaris performed very well with a biomass concentration and total lipid content of 1.15 g/L and 34.2%, respectively. Finally, two Desmodesmus sp. strains showed desirable traits for biofuel-feedstock, due to their fast growth rates (1.18 and 1.08 d−1) together with high oil content (29.8% and 36.7% of DW).

  • 223.
    Fischer, Andreas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Chlordiazepoxide dichloromethane monosolvate2012In: Acta Crystallographica Section E: Structure Reports Online, ISSN 1600-5368, E-ISSN 1600-5368Article in journal (Refereed)
    Abstract [en]

    In the title compound (systematic name: 7-chloro-2-methyl­amino-5-phenyl-3H-1,4-benzodiazepine 4-oxide dichloro­meth­ane monosolvate), C16H14ClN3O·CH2Cl2, the seven-membered ring adopts a boat conformation with the CH2 group as the prow and the two aromatic C atoms as the stern. The dihedral angle between the benzene rings is 75.25 (6)°. The crystal structure features centrosymmetric pairs of chlordiazepoxide mol­ecules linked by pairs of N—H...O hydrogen bonds, which generate R22(12) loops.

  • 224. Florén, Anders
    et al.
    Mäger, Imre
    Langel, Ülo
    Stockholm University, Faculty of Science, Department of Neurochemistry. Tartu University, Estonia.
    Uptake kinetics of cell-penetrating peptides2011In: Cell-penetrating peptides: Methods and Protocols, Humana Press, 2011, p. 117-128Chapter in book (Refereed)
    Abstract [en]

    As our knowledge increases about the diversity in uptake mechanisms displayed by cell-penetrating peptides (CPP), the concept of CPP uptake kinetics becomes increasingly complex. Here, we present three different assays that can be used for studying different kinetic aspects of CPP-mediated delivery: intracellular accumulation and membranolytical effects, intracellular CPP-cargo detachment, and finally a functional readout of a biological action from the delivered cargo. Unlike the traditional end-point measurements that give a static postincubation readout, these assays are all dynamic, real-time, in situ measurements obtained during incubation. A combination of some (or all) of these different assays gives us not only interesting kinetic information about the uptake routes but also provides a simple and valuable methodology for the evaluation of potential drug candidates based on the chemical modification of CPPs by cargo attachment.

  • 225.
    Fogden, Andrew
    et al.
    YKI, Institute for Surface Chemistry, Stockholm, Sweden.
    Vyoerykkae, Jouko
    YKI, Institute for Surface Chemistry, Stockholm, Sweden.
    Corkery, Robert W.
    YKI, Institute for Surface Chemistry, Stockholm, Sweden.
    An aqueous dispersion, a coated subject and use of an aqueous dispersion2007Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    There is disclosed an aqueous dispersion comprising a) inorganic particles b) at least one fatty acid or a salt thereof, c) a polymeric binder, and d) water, wherein said aqueous dispersion is free of organic solvent. There is also disclosed use of an aqueous dispersion comprising a) inorganic particles, b) at least one fatty acid or a salt thereof, c) a polymeric binder, and d) water, as a coating on a substrate surface, wherein said surface after coating displays an equilibrium contact angle higher than 120° degrees, preferably more than 135°, most preferably more than 150° for a drop of water on the surface. There is also disclosed a method for coating a substrate comprising contacting said substrate with the aqueous dispersion. The coating allows application in one step, it is non-toxic, safe for food packaging, and environmentally friendly as well as inexpensive.

  • 226.
    Fogden, Andrew
    et al.
    YKI, Institute for Surface Chemistry, Stockholm, Sweden.
    Vyoerykkae, Jouko
    YKI, Institute for Surface Chemistry, Stockholm, Sweden.
    Corkery, Robert W.
    YKI, Institute for Surface Chemistry, Stockholm, Sweden.
    An aqueous hydrophobic coating composition comprising a fatty acid or a salt thereof2007Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    There is disclosed an aqueous dispersion to be used in the manufacture of a hydrophobic coating, wherein said aqueous dispersion comprises: inorganic particles, at least one fatty acid or a salt thereof, a polymeric binder, and water. There is further disclosed a method for preparing an aqueous dispersion and a method of coating a substrate. There is also disclosed a subject coated with the method. The coating can be applied in one step, it is non-toxic, safe for food packaging, and relatively environmentally friendly as well as inexpensive.

  • 227.
    Forslund, Mattias
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Claesson, Per M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Octadecanethiol as Corrosion Inhibitor for Zinc and Patterned Zinc-Copper in Humidified Air with Formic Acid2014In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 161, no 6, p. C330-C338Article in journal (Refereed)
    Abstract [en]

    The corrosion inhibition efficiency of octadecanethiol (ODT) for zinc and a zinc-copper patterned model sample (Zn-Cu) has been explored during exposure in an atmosphere that mimics indoor atmospheric corrosion containing humidified air (80% relative humidity at 20 degrees C) and formic acid (around 100 ppb). The corrosion kinetics were monitored in situ with infrared reflection absorption spectroscopy, and the local nature of corrosion effects post-analyzed with complementary scanning electron microscopy, atomic force microscopy and confocal Raman spectroscopy. ODT shows initially a corrosion inhibiting ability both on zinc and on Zn-Cu. This ability decreases with time due to local removal of ODT, which causes micro-galvanic effects that eventually result in corrosion rates that exceed those for the uncovered samples. On bare and ODT-covered samples, the presence of a copper-zinc junction results in both accelerated corrosion and in structurally more developed corrosion products. Overall, the results suggest that ODT can function as a temporary corrosion inhibitor in representative indoor environments on zinc and zinc with zinc-copper junctions.

  • 228.
    Forslund, Mattias
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Claesson, Per Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Lin, C.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Micro-galvanic corrosion effects on patterned copper-zinc samples during exposure in humidified air containing formic acid2013In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 160, no 9, p. C423-C431Article in journal (Refereed)
    Abstract [en]

    Corrosion in indoor atmospheric environments is often triggered by carboxylic acids, especially at higher relative humidity. Microgalvanic effects can lead to severe corrosion, particularly important in miniature devices with small-sized metallic components. To elucidate the mechanism of micro-galvanic corrosion effects, well-defined zinc-copper patterned samples were investigated during exposure to 100 ppb formic acid (HCOOH) and 80% relative humidity at 20°C. The corrosion effects were monitored quantitatively with in situ infrared absorption spectroscopy, and the corrosion products characterized with scanning electron microscopy, confocal Raman microscopy, and atomic force microscopy. The nature of corrosion on zinc on the patterned samples was compared with that on pure zinc and turned out to result, not only in several times higher corrosion kinetics, but also in different corrosion products with respect to distribution, morphology, and composition. Local electrochemical and chemical gradients across the copper-zinc borders resulted in characteristic hemispherically shaped corrosion products at the zinc-copper junction, and in the formation of zinc formate dihydrate (Zn(HCOO)2 · 2H 2O) and crystalline zinc oxide (ZnO), phases not identified on pure zinc. In all, the micro-galvanic effects on the patterned samples resulted in accelerated corrosion kinetics and in structurally more developed corrosion products.

  • 229.
    Fredriksson, Mårten
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Physics (from 2013).
    Syftet med NTA i kemi: Fjärdeklasselevers uppfattning av syftet jämfört med lärarens syfte2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of my study was to contribute with increased knowledge on what ideas fourth grade pupils have about the aims of NTA in chemistry, and if their ideas correspond with the teachers´ aims. The data collection is made through group interviews with fifteen pupils and their teacher. The answers in these interviews have been inductively categorized. The results have shown that pupils don´t see the aims of the NTA-boxes as the teacher have in mind. It seems like the pupils´ see aims in each lesson and focus on what is happening. The teacher, on the other hand, has a much more overall aim that originates from the curriculum, but which she doesn´t manage to fully communicate to the pupils. She also intends that the pupils should develop their capability of reasoning, which they do during classroom discussions. In addition to this, the pupils also find classroom discussions both interesting and educational. Time is given for classroom discussions which gives an opportunity for scientific literacy.

  • 230.
    Freitag, Marina
    et al.
    Uppsala Univ, Dept Chem Angstrom Lab, Sweden..
    Quentin, Daniel
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Pazoki, Meysam
    Uppsala Univ, Dept Chem Angstrom Lab, Sweden..
    Sveinbjornsson, Kari
    Uppsala Univ, Dept Chem Angstrom Lab, Sweden..
    Zhang, Jinbao
    Uppsala Univ, Dept Chem Angstrom Lab, Sweden..
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. State Key Laboratory of Fine Chemicals, DUT-KTH Joint Education and Research Center on Molecular Devices, Dalian University of Technology (DUT), Dalian, China.
    Hagfeldt, Anders
    Uppsala Univ, Dept Chem Angstrom Lab, Sweden..
    Boschloo, Gerrit
    Uppsala Univ, Dept Chem Angstrom Lab, Sweden..
    High-efficiency dye-sensitized solar cells with molecular copper phenanthroline as solid hole conductor2015In: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 8, no 9, p. 2634-2637Article in journal (Refereed)
    Abstract [en]

    Copper phenanthroline complexes in the solid phase can act as efficient molecular hole transporting material (HTM) for hybrid solar cells. We prepared solid-state dye-sensitized solar cells with the organic dye LEG4 and bis(2,9-dimethyl-1,10-phenanthroline)copper(I/II) (Cu(dmp)(2)) and achieved power conversion efficiencies of more than 8% under 1000 W m(-2) AM1.5G illumination, with open-circuit potentials of more than 1.0 V. The successful application of a copper-complex based HTM paves the way for low-cost and efficient hybrid solar cells, as well as for other opto-electronic devices.

  • 231.
    Friberg, Stig E.
    et al.
    Dept of Chemistry, Clarkson University, Potsdam, New York, USA.
    Corkery, Robert W.
    YKI, Institute for Surface Chemistry, Stockholm, Sweden.
    Blute, Irena A.
    YKI, Institute for Surface Chemistry, Stockholm, Sweden.
    Phase Inversion Temperature (PIT) Emulsification Process2011In: Journal of Chemical and Engineering Data, ISSN 0021-9568, E-ISSN 1520-5134, Vol. 56, no 12, p. 4282-4290Article in journal (Refereed)
    Abstract [en]

    A quant. anal. is made of the phase changes during the phase inversion temp. (PIT) emulsification process of an aq. hexadecane emulsion stabilized by a tetra-ethylene glycol dodecyl ether surfactant. The mech. dispersion part of the process takes place at the PIT, at which temp. the emulsion contains three phases: (1) water, with only minute fractions of surfactant and hydrocarbon; (2) an inverse micellar soln., with modest fractions of solubilized water; and (3) a bicontinuous microemulsion, with large concurrent solubilization of both water and hydrocarbon. After the mech. action at the PIT, the emulsion is immediately cooled to temps. beneath the PIT range, reducing the no. of phases in the emulsion to two, an oil/water (O/W) microemulsion with moderate surfactant and hydrocarbon content, and an inverse micellar hydrocarbon soln. with a significantly greater surfactant fraction. The emulsion is characterized by its large fraction of extremely small oil drops, significantly smaller than expected from the mech. process. These drops are commonly assumed to emanate from the hydrocarbon fraction of the original bicontinuous microemulsion, the small size of the oil drops being a rational consequence of the colloidal dispersion prior to the phase sepn. The quant. anal. of the phase fractions vs. temp. revealed this assumption to be premature. The original water phase is not the final aq. phase in the emulsion; this phase is instead formed from the microemulsion phase by absorbing the original water phase, gradually modifying its own structure to become water-continuous with the originally large hydrocarbon fraction reduced to modest levels. In the process, a part of the original microemulsion is sepd., forming the small oil drops. [on SciFinder(R)]

  • 232.
    Friedman, Ran
    et al.
    Department of Biochemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich .
    Caflisch, A
    Discovery of plasmepsin inhibitors by fragment-based docking and consensus scoring2009In: ChemMedChem, ISSN 1860-7179, E-ISSN 1860-7187, Vol. 4, no 8, p. 1317-1326Article in journal (Refereed)
    Abstract [en]

    Plasmepsins (PMs) are essential proteases of the plasmodia parasites and are therefore promising targets for developing drugs against malaria. We have discovered six inhibitors of PM II by high-throughput fragment-based docking of a diversity set of ∼40 000 molecules, and consensus scoring with force field energy functions. Using the common scaffold of the three most active inhibitors (IC50=2–5 μM), another seven inhibitors were identified by substructure search. Furthermore, these 13 inhibitors belong to at least three different classes of compounds. The in silico approach was very effective since a total of 13 active compounds were discovered by testing only 59 molecules in an enzymatic assay. This hit rate is about one to two orders of magnitude higher than those reported for medium- and high-throughput screening techniques in vitro. Interestingly, one of the inhibitors identified by docking was halofantrine, an antimalarial drug of unknown mechanism. Explicit water molecular dynamics simulations were used to discriminate between two putative binding modes of halofantrine in PM II.

  • 233. Friedman, Ran
    et al.
    Caflisch, A
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Pepsinogen-like activation intermediate of plasmepsin II revealed by molecular dynamics analysis2008In: Proteins: Structure, Function, and Bioinformatics, ISSN 0887-3585, E-ISSN 1097-0134, Vol. 73, no 4, p. 814-827Article in journal (Refereed)
  • 234.
    Friedman, Ran
    et al.
    University of Zürich, Switzerland.
    Caflisch, A.
    The Protonation State of the Catalytic Aspartates in Plasmepsin II2007In: FEBS Letters, ISSN 0014-5793, E-ISSN 1873-3468, Vol. 581, p. 4120-4124Article in journal (Refereed)
  • 235. Fronzoni, Giovanna
    et al.
    Baseggio, Oscar
    Stener, Mauro
    Hua, Weijie
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Tian, Guangjun
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Luo, Yi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. University of Science and Technology of China.
    Apicella, Barbara
    Alfe, Michela
    de Simone, Monica
    Kivimäki, Antti
    Coreno, Marcello
    Vibrationally resolved high-resolution NEXAFS and XPS spectra of phenanthrene and coronene2014In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 141, no 4, p. 044313-Article in journal (Refereed)
    Abstract [en]

    We performed a combined experimental and theoretical study of the C1s Near-Edge X-ray Absorption Fine-Structure (NEXAFS) spectroscopy and X-ray Photoelectron Spectroscopy in the gas phase of two polycyclic aromatic hydrocarbons (phenanthrene and coronene), typically formed in combustion reactions. In the NEXAFS of both molecules, a double-peak structure appears in the C1s -> LUMO region, which differ by less than 1 eV in transition energies. The vibronic coupling is found to play an important role in such systems. It leads to weakening of the lower-energy peak and strengthening of the higher-energy one because the 0 - n (n > 0) vibrational progressions of the lower-energy peak appear in nearly the same region of the higher-energy peak. Vibrationally resolved theoretical spectra computed within the Frank-Condon (FC) approximation and linear coupling model agree well with the high-resolution experimental results. We find that FC-active normal modes all correspond to in-plane vibrations.

  • 236.
    Fröberg, Henric
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    A metaproteomics-based method for environmental assessment: A pilot study2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Metaproteomics, as a proteomic approach to analyse environmental samples, is a new and expanding field of research. The field promises new ways of determining the status of the organisms present in a sample, and could provide additional information compared to metagenomics. Being a novel field of research, robust methods and protocols have not yet been established. In this thesis, we examine several methods for a reliable extraction of protein from soil and periphyton samples. The extraction should preferably be fast, compatible with downstream analysis by mass spectrometry and extract proteins in proportion to their presence in the original sample. A variety of methods and buffers were used to extract proteins from soil and periphyton samples. Concentration determinations showed that all of these methods extracted enough protein for further analysis. For purification and digestion of the samples, several methods were used. The purified samples were analysed on three different mass spectrometers, with the Orbitrap Velos Pro delivering the best results. The results were matched against four genomic and metagenomic databases for identification of proteins, of which the UniProt/SwissProt database gave the best result. A maximum of 52 proteins were identified from periphyton samples when searching against UniProt/SwissProt with strict settings, of which the majority were highly conserved proteins. The main limitation for this type of work is currently the lack of proper metagenomic databases.

  • 237.
    Fu, Qiang
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Luo, Yi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Active sites of Pd-doped flat and stepped Cu(111) surfaces for H 2 dissociation in heterogeneous catalytic hydrogenation2013In: ACS Catalysis, ISSN 2155-5435, Vol. 3, no 6, p. 1245-1252Article in journal (Refereed)
    Abstract [en]

    It has been shown in recent experiments that the Cu(111) surface doped by a small amount of Pd atoms can exhibit excellent catalytic performance toward the dissociation of H2 molecules. Here we performed systematic first-principles calculations to investigate the corresponding mechanism. Our results clearly demonstrate that a very small number of Pd atoms in the subsurface layer can effectively reduce the energy barrier of H2 dissociation, making the ensembles composed of the surface and contiguous subsurface Pd atoms as the active sites. The catalytic activity can be further improved if the Pd atoms are doped in the stepped Cu surfaces. The impact of the subsurface Pd atoms comes from an enhanced surface-adsorbate interaction caused by adjusting the electronic structure of the substrate. The important role played by the subsurface atoms offers an efficient approach to finely tune the surface activity by a very limited number of atoms. Our findings should be very useful for understanding and improving the catalytic properties of alloy systems for the industrially important hydrogenation reactions.

  • 238.
    Gabrielsson, Erik
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Ellis, Hanna
    Feldt, Sandra
    Tian, Haining
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Boschloo, Gerrit
    Hagfeldt, Anders
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Convergent/Divergent Synthesis of a Linker-Varied Series of Dyes for Dye-Sensitized Solar Cells Based on the D35 Donor2013In: Advanced Energy Materials, ISSN 1614-6832, Vol. 3, no 12, p. 1647-1656Article in journal (Refereed)
    Abstract [en]

    A series of four new dyes, based on the D35 type donor moiety with varied linker units, is synthesized using a facile convergent/divergent method, enabled by an improved synthesis of the D35 donor. The dyes are evaluated in dye sensitized solar cells with Co(II/III)(bpy)(3)-based electrolytes. By extending the linker fragment, higher photocurrents and solar energy conversion efficiencies are achieved. It is also found that the linker unit plays a crucial role in maintaining a high open-circuit photovoltage. Based on the photovoltaic performance it is concluded that the hexylthiophene unit is the most suitable for this purpose, as it allows further enhancement of the already high open-circuit voltage of D35 to 0.92 V. The best dye in this series reaches an efficiency of 6.8%.

  • 239. Gadjieva, Rena
    et al.
    Mamedov, Fikret
    Albertsson, Per-Åke
    Styring, Stenbjörn
    Fractionation of the thylakoid membranes from tobacco. A tentative isolation of “end membrane” and purified “stroma lamellae” membranes1999In: Biochimica et Biophysica Acta - Bioenergetics, ISSN 0005-2728, E-ISSN 1879-2650, Vol. 1411, p. 92-100Article in journal (Refereed)
  • 240. Gadjieva, Rena
    et al.
    Mamedov, Fikret
    Renger, Gernot
    Styring, Stenbjörn
    Interconversion of low and high potential forms of cytochrome b559 in tris-washed photosystem II membranes under aerobic/anaerobic conditions1999In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Biochem, Vol. 38, p. 10578-10584Article in journal (Refereed)
  • 241.
    Galushin, Sergey
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Power Safety. AlbaNova Univ Ctr, SE-10691 Stockholm, Sweden.
    Kudinov, Pavel
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Power Safety. AlbaNova Univ Ctr, SE-10691 Stockholm, Sweden.
    Sensitivity analysis of debris properties in lower plenum of a Nordic BWR2018In: Nuclear Engineering and Design, ISSN 0029-5493, E-ISSN 1872-759X, Vol. 332, p. 374-382Article in journal (Refereed)
    Abstract [en]

    Severe accident management (SAM) in Nordic Boiling Water Reactors (BWR) employs ex-vessel core debris coolability. The melt released from the vessel is poured into a deep pool of water and is expected to fragment, quench, and form a coolable debris bed. Success of the strategy is contingent upon the melt release mode from the vessel, which determine conditions for (i) the debris bed coolability, (ii) steam explosion that present credible threats to containment integrity. Melt release conditions are recognized as the major source of uncertainty in quantification of the risk of containment failure in Nordic BWRs. The characteristics of melt release are determined by the in-vessel accident scenarios and phenomena, subject to aleatory and epistemic uncertainties respectively. Specifically, properties of the debris relocated into the lower head determine conditions for the corium interactions with the vessel structures (such as instrumentation guide tubes IGTs, control rod guide tubes CRGTs), vessel failure and melt release. This work is focused on the evaluation of uncertainty in core degradation progression and its effect on the resultant properties of relocated debris in lower plenum of Nordic BWR. We use MELCOR code for prediction of the accident progression. The main goal of this paper is to characterize the range of possible debris properties in lower plenum and its sensitivity towards different modelling parameters, which is of paramount importance for the analysis of in-vessel debris coolability and vessel failure mode in the risk assessment framework.

  • 242.
    Gan, Zhixing
    et al.
    Nanjing Normal Univ, Sch Phys & Technol, Key Lab Optoelect Technol Jiangsu Prov, Nanjing 210023, Jiangsu, Peoples R China..
    Pan, Pengfei
    Nanjing Normal Univ, Sch Phys & Technol, Key Lab Optoelect Technol Jiangsu Prov, Nanjing 210023, Jiangsu, Peoples R China..
    Chen, Zhihui
    Taiyuan Univ Technol, Coll Phys & Optoelect, Minist Educ & Shanxi Prov, Key Lab Adv Transducers & Intelligent Control Sys, Taiyuan 030024, Shanxi, Peoples R China..
    Meng, Ming
    Zhoukou Normal Univ, Sch Phys & Telecommun Engn, Zhoukou 466001, Peoples R China..
    Xu, Hao
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Cellular and Clinical Proteomics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Yu, Zhizhou
    Nanjing Normal Univ, Sch Phys & Technol, Key Lab Optoelect Technol Jiangsu Prov, Nanjing 210023, Jiangsu, Peoples R China..
    Chang, Chenliang
    Nanjing Normal Univ, Sch Phys & Technol, Key Lab Optoelect Technol Jiangsu Prov, Nanjing 210023, Jiangsu, Peoples R China..
    Tao, Yongchun
    Nanjing Normal Univ, Sch Phys & Technol, Key Lab Optoelect Technol Jiangsu Prov, Nanjing 210023, Jiangsu, Peoples R China..
    Ultraviolet Photoluminescence of Carbon Nanospheres and its Surface Plasmon-Induced Enhancement2018In: Small, ISSN 1613-6810, E-ISSN 1613-6829, Vol. 14, no 16, article id 1704239Article in journal (Refereed)
    Abstract [en]

    Ultraviolet (UV) light can be used in versatile applications ranging from photo-electronic devices to biomedical imaging. In the development of new UV light sources, in this study, stable UV emission at approximate to 350 nm is unprecedentedly obtained from carbon nanospheres (CNSs). The origin of the UV fluorescence is comprehensively investigated via various characterization methods, including Raman and Fourier transform infrared analyses, with comparison to the visible emission of carbon nanodots. Based on the density functional calculations, the UV fluorescence is assigned to the carbon nanostructures bonded to bridging O atoms and dangling -OH groups. Moreover, a twofold enhancement in the UV emission is acquired for Au-carbon core-shell nanospheres (Au-CNSs). This remarkable modification of the UV emission is primarily ascribed to charge transfer between the CNSs and the Au surface.

  • 243.
    Gao, Li
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Sun, Xianqiang
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Tu, Yaoquan
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Eriksson, Leif A.
    Modification of the anticancer drug tamoxifen to avoid CYP2D6 polymorphism2013In: Canadian journal of chemistry (Print), ISSN 0008-4042, E-ISSN 1480-3291, Vol. 91, no 9, p. 916-924Article in journal (Refereed)
    Abstract [en]

    The prodrug tamoxifen (TAM) is the most widely used drug to treat breast cancer, and is metabolised to the active 4-hydroxy derivatives dominantly by hepatic CYP2D6. However, the application to patients with different polymorphic CYP2D6 has been under debate, because the efficacy of TAM is suspected to be suppressed in patients who have diminished CYP2D6 activity, resulting in inadequate active metabolites. We here propose modified structures, such as 4-methylTAM, which is highly possible to be activated by CYP3A, the most abundant CYP isoforms in the liver, whereby the genetic polymorphism of CYP2D6 is avoided. The diversity of CYP catalyzed metabolic paths for TAM and its derivatives are studied by quantum chemistry calculations on the reaction energies of the initial H atom abstraction steps. The ability of forming DNA adducts is compared through the formation enthalpy of the carbocation intermediate. The results suggest that the modified structures are safe with regard to forming DNA adducts and may be used as prodrugs in a wide range of patients, due to CYP3A, rather than CYP2D6, mediated activation.

  • 244.
    Gatty, M. Gilbert
    et al.
    Uppsala Univ, Dept Chem, Angstrom Lab, Phys Chem, Box 523, S-75120 Uppsala, Sweden..
    Pullen, S.
    Uppsala Univ, Dept Chem, Angstrom Lab, Phys Chem, Box 523, S-75120 Uppsala, Sweden..
    Sheibani, Esmaeil
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry.
    Tian, H.
    Uppsala Univ, Dept Chem, Angstrom Lab, Phys Chem, Box 523, S-75120 Uppsala, Sweden..
    Ott, S.
    Uppsala Univ, Dept Chem, Angstrom Lab, Phys Chem, Box 523, S-75120 Uppsala, Sweden..
    Hammarstrom, L.
    Uppsala Univ, Dept Chem, Angstrom Lab, Phys Chem, Box 523, S-75120 Uppsala, Sweden..
    Direct evidence of catalyst reduction on dye and catalyst co-sensitized NiO photocathodes by mid-infrared transient absorption spectroscopy2018In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 9, no 22, p. 4983-4991Article in journal (Refereed)
    Abstract [en]

    Co-sensitization of molecular dyes and catalysts on semiconductor surfaces is a promising strategy to build photoelectrodes for solar fuel production. In such a photoelectrode, understanding the charge transfer reactions between the molecular dye, catalyst and semiconductor material is key to guide further improvement of their photocatalytic performance. Herein, femtosecond mid-infrared transient absorption spectroscopy is used, for the first time, to probe charge transfer reactions leading to catalyst reduction on co-sensitized nickel oxide (NiO) photocathodes. The NiO films were co-sensitized with a molecular dye and a proton reducing catalyst from the family of [FeFe](bdt)(CO)(6) (bdt = benzene-1,2-dithiolate) complexes. Two dyes were used: an organic push-pull dye denoted E2 with a triarylamine-oligothiophene-dicyanovinyl structure and a coumarin 343 dye. Upon photo-excitation of the dye, a clear spectroscopic signature of the reduced catalyst is observed a few picoseconds after excitation in all co-sensitized NiO films. However, kinetic analysis of the transient absorption signals of the dye and reduced catalyst reveal important mechanistic differences in the first reduction of the catalyst depending on the co-sensitized molecular dye (E2 or C343). While catalyst reduction is preceded by hole injection in NiO in C343-sensitized NiO films, the singly reduced catalyst is formed by direct electron transfer from the excited dye E2* to the catalyst in E2-sensitized NiO films. This change in mechanism also impacts the lifetime of the reduced catalyst, which is only ca. 50 ps in E2-sensitized NiO films but is >5 ns in C343-sensitized NiO films. Finally, the implication of this mechanistic study for the development of better co-sensitized photocathodes is discussed.

  • 245. Gebauer, Denis
    et al.
    Oliynyk, Vitaliy
    Salajkova, Michaela
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Sort, Jordi
    KTH, School of Biotechnology (BIO), Glycoscience.
    Zhou, Qi
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Bergstrom, Lennart
    Salazar-Alvarez, German
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    A transparent hybrid of nanocrystalline cellulose and amorphous calcium carbonate nanoparticles2011In: NANOSCALE, ISSN 2040-3364, Vol. 3, no 9, p. 3563-3566Article in journal (Refereed)
    Abstract [en]

    Nanocellulose hybrids are promising candidates for biodegradable multifunctional materials. Hybrids of nanocrystalline cellulose (NCC) and amorphous calcium carbonate (ACC) nanoparticles were obtained through a facile chemical approach over a wide range of compositions. Controlling the interactions between NCC and ACC results in hard, transparent structures with tunable composition, homogeneity and anisotropy.

  • 246.
    Geng, Dawei
    Örebro University, School of Science and Technology.
    Gas chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry methods for the determination of environmental contaminants2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The recent developments and improvements of instrumental methods for the analyses of the environmental contaminants, especially the persistent organic pollutants (POPs), have made it possible to detect and quantify these at very low concentrations in environmental and biotic matrices.

    The main objective of this thesis is to demonstrate the capability of the atmospheric pressure chemical ionization technique (APCI), using gas chromatography coupled to tandem mass spectrometry for the determination of a wide range of environmental contaminants, including the POPs regulated by Stockholm Convention, such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), but also the derivates of PBDEs and novel brominated flame retardants (NBFRs).

    The APCI was operated in charge transfer condition, preferably producing molecular ions. Multiple reaction monitoring (MRM) experiments were optimized by adjusting cone voltage, collision energy and dwell time. Optimization of source parameters, such as gas flows and temperatures was also performed. Low concentration standards were analyzed, achieving a visible chromatographic peak for 2 fg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) demonstrating the excellent sensitivity of the system. Adequate linearity and repeatability were observed for all the studied compounds. The performance of APCI methods was validated against the conventional methods using gas chromatography coupled to high resolution mass spectrometry for chlorinated compounds in a wide range of matrices including environmental, air, human and food matrices.

    The GC-APCI-MS/MS method was successfully applied to a set of 75 human serum samples to study the circulating levels of POPs in epidemiologic studies. Moreover the method was utilized to establish temporal trends of POPs in osprey eggs samples collected during the past five decades.

  • 247.
    Geng, Dawei
    et al.
    Örebro University, School of Science and Technology.
    Ericson Jogsten, Ingrid
    Örebro University, School of Science and Technology.
    Kukucka, Petr
    Örebro University, School of Science and Technology. RECETOX Masaryk University, Brno, Czech Republic.
    Eriksson, Ulrika
    Örebro University, School of Science and Technology.
    Ekblad, Alf
    Örebro University, School of Science and Technology.
    Grahn, Hans
    Örebro University, School of Science and Technology.
    Roos, Anna
    Department for Environmental Research and Monitoring, Swedish Museum of Natural History, Stockholm, Sweden.
    Temporal Trends of Polychlorinated Biphenyls, Organochlorine Pesticides and Polybrominated Diphenyl Ethers in Osprey Eggs in Sweden over the Years 1966 – 2013Manuscript (preprint) (Other academic)
  • 248.
    Geng, Dawei
    et al.
    Örebro University, School of Science and Technology.
    Kukucka, Petr
    Örebro University, School of Science and Technology. RECETOX Masaryk University, Brno, Czech Republic.
    Ericson Jogsten, Ingrid
    Örebro University, School of Science and Technology.
    Analysis of Novel and Legacy Brominated Flame Retardants Including Their Derivates by Atmospheric Pressure Chemical Ionization Using Gas Chromatography Coupled to Triple Quadrupole Mass SpectrometryManuscript (preprint) (Other academic)
  • 249.
    Ghadami Yazdi, Milad
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Material Physics, MF.
    H. Moud, Pouya
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology. KTH.
    Marks, Kess
    Piskorz, Witold
    Öström, Henrik
    Hansson, Tony
    Kotarba, Andrzej
    Engvall, Klas
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Göthelid, Mats
    KTH, School of Engineering Sciences (SCI), Applied Physics, Material Physics, MF.
    Naphthalene on Ni(111): experimental and theoretical insights into adsorption, dehydrogenation and carbon passivationManuscript (preprint) (Other academic)
    Abstract [en]

    An attractive solution to mitigate tars and also to decompose lighter hydrocarbons in biomass gasification is secondary catalytic reforming, converting hydrocarbons to useful permanent gases. Albeit in use for long time in fossil feedstock catalytic steam reforming, the understanding of the catalytic processes is still limited. Naphthalene is typically present in the biomass gasification gas and to further understand the elementary steps of naphthalene transformation, we investigated the temperature dependent naphthalene adsorption, dehydrogenation and passivation on Ni(111). TPD (temperature programmed desorption) and STM (scanning tunneling microscopy) in ultra-high vacuum environment from 110 K up to 780 K, combined with DFT (density functional theory) were used in the study. Room temperature adsorption results in a flat naphthalene monolayer. DFT favors the di-bridge[7] geometry but the potential energy surface is rather smooth. DFT also reveals a pronounced dearomatization and charge transfer from the adsorbed molecule into the nickel surface. Dehydrogenation occurs in two steps, with two desorption peaks at approximately 450 K and 600 K. The first step is due to partial dehydrogenation generating active hydrocarbon species that at higher temperatures migrates over the surface forming graphene. The graphene formation is accompanied by desorption of hydrogen in the high temperature TPD peak. The formation of graphene effectively passivates the surface both for hydrogen adsorption and naphthalene dissociation. In conclusion, the obtained results on the model naphthalene and Ni(111) system, provides insight into elementary steps of naphthalene adsorption, dehydrogenation and carbon passivation, which may serve as a good starting point for rational design, development and optimization of the Ni catalyst surface, as well as process conditions, for the aromatic hydrocarbon reforming process.

  • 250.
    Ghanadpour, Maryam
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Cellulose-based fire retardant material2014In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 247, p. 247-CELL-Article in journal (Other academic)
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