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  • 301.
    Elsamadony, Mohamed
    et al.
    Tokyo Inst Technol, Japan; Tanta Univ, Egypt.
    Elreedy, Ahmed
    Karlsruhe Inst Technol, Germany; Alexandria Univ, Egypt.
    Mostafa, Alsayed
    Inha Univ, South Korea.
    Fujii, Manabu
    Tokyo Inst Technol, Japan.
    Gescher, Johannes
    Karlsruhe Inst Technol, Germany; Karlsruhe Inst Technol KIT, Germany.
    Shakeri Yekta, Sepehr
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten.
    Schnurer, Anna
    Swedish Univ Agr Sci, Sweden.
    Gaillard, Jean-Francois
    Northwestern Univ, IL 60208 USA; Tokyo Inst Technol, Japan.
    Pant, Deepak
    Flemish Inst Technol Res VITO, Belgium.
    Perspectives on Potential Applications of Nanometal Derivatives in Gaseous Bioenergy Pathways: Mechanisms, Life Cycle, and Toxicity2021Inngår i: ACS Sustainable Chemistry and Engineering, E-ISSN 2168-0485, Vol. 9, nr 29, s. 9563-9589Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nanosized metal derivatives (NMDs), referring to metals and their oxides, are extensively utilized as additives for anaerobic digestion (AD) and dark fermentation (DF) processes, for enhancing the production of methane (CH4) and hydrogen (H-2), respectively. NMDs-derived positive impacts were widely confirmed in many previous studies; however, no consensus exists about how these have been acquired. Undoubtedly, NMDs affect extracellular electron transfer (EET). Consequently, we explore how biotic-biotic interactions, referring to direct interspecies electron transfer (DIET) among AD partners, and biotic-abiotic exchanges, which are mediated by redox reactions with metals, are affected. In this perspective, the mechanisms behind all those effects are reviewed and explained in detail, considering the specific properties of each NMD, e.g., size and type. We discuss previous studies that offer contradicting interpretations about which process dominates metal oxidation, metal reduction, or DIET. In addition, the fate of NMDs residues in the digestate after the treatment process is discussed, focusing on NMDs toxicity. From previous literature, the environmental impacts are evaluated for the production process of NMDs that are utilized in AD and DF processes via life-cycle assessment. This review provides a comprehensive understanding of NMDs-microbes interactions, which are mandatory for (i) building clear scientific knowledge about processes in play and (ii) engineering favorable conditions to achieve optimum yields in AD and DF processes.

  • 302.
    El-Shabasy, Rehan
    et al.
    KTH Royal Inst Technol, Dept Chem, Ecol Chem Grp, Sch Chem Sci & Engn, Stockholm, Sweden;Menoufia Univ, Fac Sci, Dept Chem, Shibin Al Kawm 32512, Egypt.
    Yosri, Nermeen
    Menoufia Univ, Fac Sci, Dept Chem, Shibin Al Kawm 32512, Egypt.
    El-Seedi, Hesham
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Farmakognosi. KTH Royal Inst Technol, Dept Chem, Ecol Chem Grp, Sch Chem Sci & Engn, Stockholm, Sweden;Menoufia Univ, Fac Sci, Dept Chem, Shibin Al Kawm 32512, Egypt.
    Shoueir, Kamel
    Kafrelsheikh Univ, Inst Nanosci & Nanotechnol, Kafrelsheikh 33516, Egypt.
    El-Kemary, Maged
    Kafrelsheikh Univ, Inst Nanosci & Nanotechnol, Kafrelsheikh 33516, Egypt.
    A green synthetic approach using chili plant supported Ag/Ag2O@P25 heterostructure with enhanced photocatalytic properties under solar irradiation2019Inngår i: Optik (Stuttgart), ISSN 0030-4026, E-ISSN 1618-1336, Vol. 192, artikkel-id 162943Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    As the environmental pollution is a global, catastrophic occurrence, green synthesis of different catalysts has long been pursued. Herein, Capsicum annuum L (chili) extract-based catalysts were used for the fabrication of Ag/Ag2O nanoparticles (NPs) without harsh conditions. The prepared Ag/Ag2O NPs were uniform with an average size of 11.4 nm. The Ag/Ag2O was smoothly coupled with P25 to produce Ag/Ag2O@P25 photocatalyst which had effective electron-hole pair separation and active sites for high photocatalytic activity. The catalyst degraded 98.7% of the model pollutant methylene blue (MB) and catalytic conversion of 100% 2,4-dinitroaniline (2,4-DNA) within 60 s were realized under energy saving solar-light illumination, matching the rules of "green chemistry". In addition, the prepared photocatalyst exhibited superior stability and reusability, and the hot filtration test proved the heterogeneity of the catalyst.

  • 303. Emam, A. N.
    et al.
    Mohamed, M. B.
    Girgis, E.
    Rao, K. Venkat
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Hybrid magnetic-plasmonic nanocomposite: Embedding cobalt clusters in gold nanorods2015Inngår i: RSC Advances, E-ISSN 2046-2069, Vol. 5, nr 44, s. 34696-34703Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 304. Emanuelsson, Rikard
    et al.
    Löfås, Henrik
    Wallner, Andreas
    Nauroozi, Djawed
    Baumgartner, Judith
    Marschner, Christoph
    Ahuja, Rajeev
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad materialfysik. 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 Exchange2014Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 20, nr 30, s. 9304-9311Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 305.
    Eneborg, Alexander
    RISE - Research Institutes of Sweden, Biovetenskap och material, Yta, process och formulering. KTH Royal Institute of Technology, Sweden.
    Improvement and Characterization of Aqueous Graphene Dispersions2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Graphene has many outstanding properties which make it a prime candidate for new technology. At the current time it is very difficult and expensive to produce large sheets of graphene, but there are many applications where that is not necessary and smaller flakes of graphene can be used instead. A practical way of handling these graphene flakes is in a dispersion, especially a water-based dispersion have many benefits. Such a stable dispersion of functionalized graphene is produced, improved, and characterized in this project. An aqueous system that was developed in two previous M.Sc. theses, each determining a suitable graphene powder and stabilizer, was used as a starting point with the main purpose being to improve the yield. The method used to produce these dispersions can be described as sonicating graphene powder in a solution of water and stabilizer followed by centrifuging to remove un-dispersed graphene particles. Experiments were carried out examining the possibility of dispersing those previously undispersed graphene flakes, combining the stabilizer with several surfactants, optimizing the centrifuge speed and time, refining the sonication procedure with longer exposure time and cooling, narrowing the size-distribution of the original stabilizer through ultrafiltration, and removing excessive unbound stabilizer through ultrafiltration. Samples were characterized with UV-vis, SEM, TGA, Electrophoretic light scattering, and Laser diffraction spectroscopy. It was discovered that the yield from the graphene powder was heavily dependent on sonication time and centrifugation conditions. The gain from increasing sonication time showed that most, if not all, of the un-dispersed graphene flakes previously considered lost could in fact be dispersed. In an industrial setting any un-dispersed flakes could simply be added to the next batch. Reducing the centrifugation speed as well as time increased the concentration of graphene to more than twice as high, and that gain comes solely from the larger graphene flakes. Thusly the previous problem with a low yield was shown to have been caused by too little sonication and too much centrifugation. The particle size analysis did show a small reduction in flake size as the sonication time was increased, but when those dispersions were characterized in SEM they all formed even films with no discernable difference between them. Purifying the scaled up dispersions by removing excess stabilizer through ultrafiltration was performed to three different degrees, 0 %, 50 % and 95 %, for a total of three dispersions of 100ml. All three dispersions were shown to be highly stable, with no apparent reduction in graphene concentration over 5 weeks and a zeta potential averaging below -50mV. The TGA results reinforce the UV-vis results, proving that the purification worked as intended.

  • 306.
    Engdahl, Cecilia
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Knutsson, Sofie
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Fredriksson, Sten-Åke
    Linusson, Anna
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Bucht, Göran
    Ekström, Fredrik
    Acetylcholinesterases from the Disease Vectors Aedes aegypti and Anopheles gambiae: Functional Characterization and Comparisons with Vertebrate Orthologues2015Inngår i: PLOS ONE, E-ISSN 1932-6203, Vol. 10, nr 10, artikkel-id e0138598Artikkel i tidsskrift (Fagfellevurdert)
    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.

    Fulltekst (pdf)
    fulltext
  • 307.
    ENMYREN, CAROLINE
    KTH, Skolan för kemivetenskap (CHE).
    Syntes av betulinderivat och deras applikation som mjukgörare för PVC2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    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.

  • 308.
    Eriksen, Jonas Borregaard
    et al.
    Univ Southern Denmark, Dept Phys Chem & Pharm, Odense M, Denmark..
    Jacobsen, Ann-Christin
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för farmaci. Univ Southern Denmark, Dept Phys Chem & Pharm, Odense M, Denmark..
    Christensen, Katrine Taekker
    Univ Southern Denmark, Dept Phys Chem & Pharm, Odense M, Denmark..
    Bauer-Brandl, Annette
    Univ Southern Denmark, Dept Phys Chem & Pharm, Odense M, Denmark..
    Brandl, Martin
    Univ Southern Denmark, Dept Phys Chem & Pharm, Odense M, Denmark..
    'Stirred not Shaken!' Comparing Agitation Methods for Permeability Studies Using a Novel Type of 96-Well Sandwich-Plates2022Inngår i: Journal of Pharmaceutical Sciences, ISSN 0022-3549, E-ISSN 1520-6017, Vol. 111, nr 1, s. 32-40Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In order to achieve a high sample throughput, permeation experiments are often carried out using 96-well sandwich plates. Even though agitation is regarded as important, permeation studies in 96-well format are often carried out without agitation since orbital shaking, the most common agitation method for 96-well plates, has been reported to create difficulties (e.g., well-to-well cross-talk), and high cost and low availability limits the use of other agitation techniques (e.g., magnetic stirring). This study investigates how orbital shaking and magnetic stirring affect the apparent permeability of model compounds with different water-solubilities (methylene blue, carbamazepine, and albendazole) using a novel 96-well sandwich plate comprising a cellulose-hydrate membrane (PermeaPlain (R) plate). Orbital shaking was found less efficient than magnetic stirring in terms of homogeneously distributing a small volume of dye within the donor compartment. Furthermore, in terms of achieving maximum trans-barrier flux, magnetic stirring was found a more effective agitation method than orbital shaking. Obviously, with orbital shaking the medium in the bottom compartment of the sandwich plates never was mixed in-phase. The impact of insufficient mixing on permeation was found strongest with the most lipophilic compound, which correlates with literature reports that the contribution of the unstirred water layer towards the overall resistance of the barrier is most expressed in case of lipophilic drugs. Finally, it was tested how different liquid volumes in the bottom compartment of the plates affect the well-to-well cross-talk during permeation experiments under orbital shaking. This study revealed that 250-300 mu L should be used in the bottom compartment of the sandwich plates to reduce well-to-well cross-talk when using orbital shaking for agitation. (C) 2021 Published by Elsevier Inc. on behalf of American Pharmacists Association.

    Fulltekst (pdf)
    FULLTEXT01
  • 309.
    Eriksson, Jonas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi.
    Gene therapy tools: oligonucleotides and peptides2016Doktoravhandling, med artikler (Annet vitenskapelig)
    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.

    Fulltekst (pdf)
    Gene therapy tools: oligonucleotides and peptides
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  • 310.
    Eriksson, Lars
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Crystal Structure of Methyl 3-O-α-D-Glucopyranosyl 2-Acetamido-2-Deoxy-α-D-Galactopyranoside Hydrate2023Inngår i: Journal of Chemical Crystallography, ISSN 1074-1542, E-ISSN 1572-8854, Vol. 53, nr 3, s. 400-406Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Methyl 3-O-α-D-glucopyranosyl 2-acetamido-2-deoxy-α-D-galactopyranoside as a monohydrate, C15H27NO11·H2O, crystallizes in space group P212121, with four molecules in the unit cell. It constitutes the methyl glycoside of the carbohydrate part of the teichoic acid type polysaccharide from Micrococcus sp. A1, in which the disaccharides are joined through phosphodiester linkages. The conformation of the disaccharide is described by the glycosidic torsion angles ϕ =  − 31° and ψ =  + 1°, and the hydroxymethyl groups of the constituent monosaccharides are present in the gg and gt conformations for the sugar residues having the gluco- and galacto-configuration, respectively. For the N-acetyl group at C2 of the galactosamine residue the torsion angle τH = 147°, i.e., the amide proton has an antiperiplanar relationship to H2 of the sugar ring. The structure shows extensive hydrogen bonding along the a-direction, including the water molecule, and forms sheets with hydrophilic interactions within the sheets as a result of hydrogen bonding between disaccharides as well as hydrophobic interactions between the sheets, in particular, amongst methyl groups of the N-acetyl group of the α-D-GalpNAc residue in the disaccharides.

  • 311.
    Eriksson, Ulrika
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Contribution of polyfluoroalkyl phosphate esters (PAPs) and other precursor compounds to perfluoroalkyl carboxylates (PFCAs) in humans and the environment2016Doktoravhandling, med artikler (Annet vitenskapelig)
    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.

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    Contribution of polyfluoroalkyl phosphate esters (PAPs)
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  • 312.
    Eriksson, Ulrika
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Haglund, Peter
    Umeå University, Umeå, Sweden.
    Kärrman, Anna
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Contribution of precursor compounds to the release of per- and polyfluoroalkyl substances (PFASs) from waste water treatment plants (WWTPs)Manuskript (preprint) (Annet vitenskapelig)
  • 313.
    Eriksson, Ulrika
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    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 universitet, Institutionen för naturvetenskap och teknik.
    Temporal trends of PFSAs, PFCAs and selected precursors in Australian serum from 2002 to 2013Manuskript (preprint) (Annet vitenskapelig)
  • 314. Eshagh, Mehdi
    et al.
    Bagherbandi, Mohammad
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Geodesi och geoinformatik.
    Smoothing impact of isostatic crustal thickness models on local integral inversion of satellite gravity gradiometry data2011Inngår i: ACTA GEOPHYSICA, ISSN 1895-6572, Vol. 59, nr 5, s. 891-906Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 315.
    Eskandari, Vahid
    et al.
    Univ Kashan, Iran.
    Sadeghi, Mohammadreza
    Linköpings universitet, Tekniska fakulteten.
    Hadi, Amin
    Yasuj Univ Med Sci, Iran.
    Physical and chemical properties of nano-liposome, application in nano medicine2021Inngår i: JOURNAL OF COMPUTATIONAL APPLIED MECHANICS, ISSN 2423-6713, Vol. 52, nr 4, s. 751-767Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The liposome is derived from two Greek roots: Lipo meaning fat and Some meaning structure. Liposomes can be made from natural phospholipids and cholesterol and, if necessary, other additives. Liposomes were first discovered by Bangham in 1961 due to their simple, self-fulfilling structure and low cost. Liposomes are spherical vesicles with a membrane composed of bilayer phospholipids that are used to release drugs or genetic material into the cell. Current research is focused on liposome technology based on the preparation and development of long-circulating liposomes, lipid components changing, and vesicles charge amount. Liposomes, in addition to pharmaceutical carriers, are used in cutaneous, respiratory, food industries, injectable, and in genetic engineering and diagnostic applications. This paper reviews the physical and chemical characteristics, structure, construction methods, and applications of nanoliposomes in various uses as drug carriers, including the treatment of specific diseases.

  • 316. Esmaily, M.
    et al.
    Blücher, D. B.
    Wreland Lindström, Rakel
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Svensson, J. -E
    Johansson, L. G.
    The influence of SO2 on the corrosion of Mg and Mg-Al alloys2015Inngår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 162, nr 6, s. C260-C269Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 317.
    Espling, Maria
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Copper-transporting proteins and their interactions with platinum-based anticancer substances2013Doktoravhandling, med artikler (Annet vitenskapelig)
    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.

    Fulltekst (pdf)
    Avhandling Maria Espling
  • 318. Etman, Ahmed
    et al.
    Halim, Joseph
    Rosen, Johanna
    MXene-based Zn-ion hybrid supercapacitors: Effects of anion carriers and MXene surface coatings on the capacities and life span2022Inngår i: Journal of Energy Storage, ISSN 2352-152X, E-ISSN 2352-1538, Vol. 52, s. 104823-104823, artikkel-id 104823Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Energy storage devices such as rechargeable batteries and supercapacitors are of great importance for establishing clean energy sources. Accordingly, the production of these devices needs to rely on sustainable and environmentally friendly materials. This report provides an insight on the use of two-dimensional transition metal carbides (MXene) based electrodes, here shown for Mo1.33CTz-Ti3C2Tz mixed MXene, in Zn-ion hybrid supercapacitors (ZHSC) using aqueous and nonaqueous (acetonitrile-based) electrolytes. The effect of anion carriers on the accessible capacity, rate capability, and life span of the MXene//Zn hybrid supercapacitor is explored in-depth. Halide carriers such as chloride (Cl−) and iodide (I−) feature a superior performance, however, a fast passivation is observed in Cl− based electrolytes and a narrow potential window is achieved in I− based electrolytes. Importantly, a few micron layer of Ti3C2Tz MXene coated on the surface of the Zn anode is found to inhibit the side reactions and passivation observed in ZnCl2 solutions, which enables the use of such low-cost Zn salt in MXene//Ti3C2Tz-coated-Zn cells. The cells can be reversibly cycled over 10,000 cycles, delivering a capacity up to 200 mAh g−1 at low rate (0.5 mV s−1) and a capacity retention of about 36% at high rate (100 mV s−1). Furthermore, the Ti3C2Tz surface coating layer enhanced the coulombic efficiency in Zn(CF3SO3)2 electrolyte without affecting the accessible capacity or the rate capability. This work sheds light on the use of MXenes in sustainable low-cost ZHSC with high energy density and power density as a positive electrode material as well as a surface coating material for the Zn negative electrode.

    Fulltekst (pdf)
    fulltext
  • 319.
    Etman, Ahmed S.
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Alexandria Univ, Egypt.
    Wang, Zhaohui
    Uppsala Univ, Sweden.
    El Ghazaly, Ahmed
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Sun, Junliang
    Peking Univ, Peoples R China.
    Nyholm, Leif
    Uppsala Univ, Sweden.
    Rosén, Johanna
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Flexible Freestanding MoO3-x-Carbon Nanotubes-Nanocellulose Paper Electrodes for Charge-Storage Applications2019Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 12, nr 23, s. 5157-5163Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Herein, a one-step synthesis protocol was developed for synthesizing freestanding/flexible paper electrodes composed of nanostructured molybdenum oxide (MoO3-x) embedded in a carbon nanotube (CNT) and Cladophora cellulose (CC) matrix. The preparation method involved sonication of the precursors, nanostructured MoO3-x, CNTs, and CC with weight ratios of 7:2:1, in a water/ethanol mixture, followed by vacuum filtration. The electrodes were straightforward to handle and possessed a thickness of approximately 12 mu m and a mass loading of MoO3-x-CNTs of approximately 0.9 mg cm(-2). The elemental mapping showed that the nanostructured MoO3-x was uniformly embedded inside the CNTs-CC matrix. The MoO3-x-CNTs-CC paper electrodes featured a capacity of 30 C g(-1), normalized to the mass of MoO3-x-CNTs, at a current density of 78 A g(-1) (corresponding to a rate of approximately 210 C based on the MoO3 content, assuming a theoretical capacity of 1339 C g(-1)), and exhibited a capacity retention of 91 % over 30 000 cycles. This study paves the way for the manufacturing of flexible/freestanding nanostructured MoO3-x-based electrodes for use in charge-storage devices at high charge/discharge rates.

    Fulltekst (pdf)
    fulltext
  • 320.
    Falk, Adrian
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Bengtsson, Emmy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Juhlin, Stina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Le, Dong
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Niklasson, Lovisa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Svensson, Karolina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Tesfamhret, Yonas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    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 poäng / 15 hpOppgave
    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.

    Fulltekst (pdf)
    fulltext
  • 321.
    Falk, Joel
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Skoglund, Nils
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Grimm, Alejandro
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Boström, Dan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Difference in phosphate speciation between sewage sludge and biomass ash from fluidized bed combustion2018Inngår i: 27th International Conference of Impacts of Fuel Quality on Power Production and the Environment, September 23–28 September, 2018, Lake Louise, Canada, 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The role of phosphorus in biomass combustion is a topic that has become increasingly relevantin recent years. Due to the demand for new sources of renewable energy and recovery of phosphorus from waste streams such as sewage sludge, research into the behavior of phosphorus during combustion is necessary for a continued development. This study aims to investigate potential differences in phosphate behavior during co-combustion of sewage sludge compared to other phosphorus-rich biomass or additives. The investigation was carried out in a bench scale bubbling fluidized bed, co-combusting six biomass blends of similar ash composition and combustion conditions but with different phosphorus association (logging residues (LR) or wheat straw (WS) with sewage sludge (SS), dried distiller’s grain (DG), or phosphoric acid (PA)). After combustion, bed ash samples, fly ash deposits and cyclone ash were collected and analyzed for elemental composition (SEM-EDS) and phase composition (XRD). Based on the XRD phase analyses, a significant difference in phosphate speciation were foundbetween biomass blends containing SS compare to DG or PA. Only two phosphate phases were identified in the ash from SS blends compared to a large variety of phosphates in ash from DG or PA blends. The difference in speciation could not be explained by a difference in ash fractionation as the elemental composition of the analyzed ash fractions were similar. Rather, the results indicate that the behavior of phosphorus in SS may be different to that in DG or PA.

  • 322.
    Fall, Andreas B.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Fiberteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lindström, Stefan B.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Fiberteknologi.
    Sprakel, Joris
    Wågberg, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Fiberteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    A physical cross-linking process of cellulose nanofibril gels with shear-controlled fibril orientation2013Inngår i: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 9, nr 6, s. 1852-1863Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 323.
    Fan, Qunping
    et al.
    Chalmers Univ Technol, Sweden.
    Ma, Ruijie
    Hong Kong Univ Sci & Technol, Peoples R China; Hong Kong Univ Sci & Technol, Peoples R China.
    Liu, Tao
    Hong Kong Univ Sci & Technol, Peoples R China; Hong Kong Univ Sci & Technol, Peoples R China.
    Yu, Jianwei
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Elektroniska och fotoniska material. Linköpings universitet, Tekniska fakulteten.
    Xiao, Yiqun
    Chinese Univ Hong Kong, Peoples R China.
    Su, Wenyan
    Chalmers Univ Technol, Sweden; Karlstad Univ, Sweden.
    Cai, Guilong
    Department of Physics, The Chinese University of Hong Kong, New Territories, 999077, Hong Kong, China.
    Li, Yuxiang
    Xian Univ Sci & Technol, Peoples R China.
    Peng, Wenhong
    Chalmers Univ Technol, Sweden.
    Guo, Tao
    Chalmers Univ Technol, Sweden.
    Luo, Zhenghui
    Hong Kong Univ Sci & Technol, Peoples R China; Hong Kong Univ Sci & Technol, Peoples R China.
    Sun, Huiliang
    Hong Kong Univ Sci & Technol, Peoples R China; Hong Kong Univ Sci & Technol, Peoples R China.
    Hou, Lintao
    Jinan Univ, Peoples R China.
    Zhu, Weiguo
    Changzhou Univ, Peoples R China.
    Lu, Xinhui
    Chinese Univ Hong Kong, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Elektroniska och fotoniska material. Linköpings universitet, Tekniska fakulteten.
    Moons, Ellen
    Karlstad Univ, Sweden.
    Yu, Donghong
    Aalborg Univ, Denmark; Sino Danish Ctr Educ & Res, Denmark.
    Yan, He
    Hong Kong Univ Sci & Technol, Peoples R China; Hong Kong Univ Sci & Technol, Peoples R China.
    Wang, Ergang
    Chalmers Univ Technol, Sweden; Zhengzhou Univ, Peoples R China.
    High-performance all-polymer solar cells enabled by a novel low bandgap non-fully conjugated polymer acceptor2021Inngår i: Science in China Series B: Chemistry, ISSN 1674-7291, E-ISSN 1869-1870, Vol. 64, nr 8, s. 1380-1388Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Anon-fully conjugated polymer as a new class of acceptor materials has shown some advantages over its small molecular counterpart when used in photoactive layers for all-polymer solar cells (all-PSCs), despite a low power conversion efficiency (PCE) caused by its narrow absorption spectra. Herein, a novel non-fully conjugated polymer acceptor PFY-2TS with a low bandgap of similar to 1.40 eV was developed, via polymerizing a large pi-fused small molecule acceptor (SMA) building block (namely YBO) with a non-conjugated thioalkyl linkage. Compared with its precursor YBO, PFY-2TS retains a similar low bandgap but a higher LUMO level. Moreover, compared with the structural analog of YBO-based fully conjugated polymer acceptor PFY-DTC, PFY-2TS shows similar absorption spectrum and electron mobility, but significantly different molecular crystallinity and aggregation properties, which results in optimal blend morphology with a polymer donor PBDB-T and better device physical processes in all-PSCs. As a result, PFY-2TS-based all-PSCs achieved a PCE of 12.31% with a small energy loss of 0.56 eV enabled by the reduced non-radiative energy loss (0.24 eV), which is better than that of 11.08% for the PFY-DTC-based ones. Our work clearly demonstrated that non-fully conjugated polymers as a new class of acceptor materials are very promising for the development of high-performance all-PSCs.

  • 324.
    Fang, Zhiyong
    et al.
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Zhang, Peili
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Wang, Mei
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Li, Fusheng
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Wu, Xiujuan
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Fan, Ke
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Sun, Licheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi. Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, State Key Lab Fine Chem, Dalian 116024, Peoples R China.;Westlake Univ, Ctr Artificial Photosynth Solar Fuels, Sch Sci, Hangzhou 310024, Peoples R China..
    Selective Electro-oxidation of Alcohols to the Corresponding Aldehydes in Aqueous Solution via Cu(III) Intermediates from CuO Nanorods2021Inngår i: ACS Sustainable Chemistry and Engineering, E-ISSN 2168-0485, Vol. 9, nr 35, s. 11855-11861Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electrochemical oxidation using renewable energy is an attractive strategy that provides a sustainable and mild approach for biomass transformation. Herein, the electrocatalytic oxidation of furfuryl alcohol in an aqueous solution was investigated using CuO nanorods. Two kinds of Cu-III intermediates, namely, (CuO2)(-) and (Cu2O6)(6-), were detected on the surface of the working electrode. (Cu2O6)(6-), generated in the potential range of 1.35-1.39 V versus the reversible hydrogen electrode (RHE), induced the oxidation of furfuryl alcohol to furaldehyde with a yield of >= 98%. (CuO2)(-), generated at a potential greater than 1.39 V versus RHE, which led to the oxidation of furfuryl alcohol to 2-furoic acid with a yield of >= 99%. Furthermore, the Cu-III-catalyzed system exhibited a measure of universal applicability, wherein (Cu2O6)(6-) and (CuO2)(-) induced the highly selective electro-oxidation of benzyl alcohol, vanillyl alcohol, and 4-pyridinemethanol to yield the corresponding aldehydes and acids, respectively.

  • 325.
    Fazilati, Mina
    et al.
    Malmö universitet, Fakulteten för hälsa och samhälle (HS), Institutionen för biomedicinsk vetenskap (BMV). Malmö universitet, Biofilms Research Center for Biointerfaces. Chalmers University of Technology.
    Ingelsten, Simon
    Chalmers University of Technology.
    Wojno, Sylwia
    Chalmers University of Technology.
    Nypelo, Tiina
    Chalmers University of Technology.
    Kadar, Roland
    Chalmers University of Technology.
    Thixotropy of cellulose nanocrystal suspensions2021Inngår i: Journal of rheology (New York, N.Y.), ISSN 0148-6055, E-ISSN 1520-8516, Vol. 65, nr 5, s. 1035-1052Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The thixotropy of cellulose nanocrystal (CNC) water suspensions is intrinsically dependent on the hierarchical structure of the suspension. The diverse hierarchies that comprise individual CNC nanoparticles and mesophase liquid crystalline domains, chiral nematic and nematic structures, contribute selectively to the rheological material response. Here, we combine rheology with polarized light imaging (PLI) to elucidate the thixotropic behavior of CNCs suspended in water. The simultaneous monitoring of PLI and rheological tests enables the observation of mesogens and their orientation dynamics. Creep, dynamic time sweep, ramped hysteresis loop, and thixotropic recovery tests combined with PLI aim to differentiate the contribution of the different hierarchical levels of CNC suspensions to their thixotropy. The range of concentrations investigated comprised biphasic (4 and 5 wt. %) and liquid crystalline phase suspensions (6, 7, and 8 wt. %). The CNC suspensions exhibited complex thixotropy behavior, such as viscosity bifurcations in creep tests and overshoot in ramped hysteresis loop tests. The restructuring and destructuring appeared to correspond to different levels of their hierarchical structure, depending mainly on the phase, in agreement with previous studies. Restructuring was attributed to re-organizations of an individual CNC, e.g., in the isotropic fraction of biphasic suspensions and at the mesogen interfaces in liquid crystalline phase suspensions. However, by increasing liquid crystalline fraction in the biphasic concentrations, restructuring could also involve mesogens, as indicated in the creep tests. For flow conditions above the yield stress, as evidenced by the ramped hysteresis and thixotropy recovery tests, destructuring was dominated by orientation in the flow direction, a process that is readily observable in the form of PLI "Maltese-cross" patterns. Finally, we show that a simple thixotropy model, while unable to capture the finer details of the suspension's thixotropic behavior, could be employed to predict general features thereof.

    Fulltekst (pdf)
    fulltext
  • 326.
    Femenia, Marc
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    Pan, Jinshan
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Korrosionslära.
    Corrosion Studies of Duplex Stainless Steels with Micrometer Resolution2004Inngår i: Journal of Corrosion Science & Engineering, E-ISSN 1466-8858, Vol. 6, s. paper 28-Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 327.
    Feng, Ailin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    The influence of repeated cleaning on corrosion and metal migration of 316L stainless steel in food contact applications2023Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Vilken påverkan som upprepad rengöring av rostfritt stål 316L inom livsmedelsindustrin har gällande dess ytegenskaper, grad av metallfrisättning och korrosionsbeteende är delvis outforskat. Vid rengöring skapar en förhöjd temperatur, olika pH-värden hos rengöringsmedlen och kloridjoner (Cl-) från kranvatten eller desinfektionsmedel en potentiellt korrosiv miljö. Felaktiga rengöringsmetoder kan öka risken för lokal korrosion, såsom gropkorrosion, vilket även påverkar metallfrisättningen under produktion och transport. Därför är det viktigt för livsmedelsindustrin att ha pålitlig information om hur upprepad rengöring påverkar ytegenskaperna, graden av metallfrisättning och förändringar i korrosionsmotstånd för att säkerställa en säker produktionsmiljö.

    Syftet med denna studie var att undersökta effekterna av upprepad rengöring av rostfritt stål av typ 316L som används för att processa livsmedel. Genom att undersöka effekter av de individuella rengöringsmedlen, H2O2, NaOH, HNO3, och CH3CO2OH, var för sig samt i en sekvens (relevant för industriellt bruk) tillhandahölls information om förändringar i ytoxiden relaterat till användning av de olika kemikalierna. 

    Resultaten visar att upprepad rengöring förändrar den kemiska sammansättningen av ytoxiderna på den rostfria stålytan (XPS) efter individuell exponering för NaOH, HNO3 och den sekventiella metoden, men visade på ingen betydande skillnad efter individuell exponering för H2O2 eller CH3CO2OH. Ingen betydande förändring i ytmorfologi kunde heller observeras (LOM). En högre mängd frisatt metall observerades i NaOH, HNO3 och den sekventiella rengöringsmetoden jämfört med H2O2, och CH3CO2OH (AAS). 

    En uppskattning av de tvättade ytornas korrosionsbeteende i kontakt med livsmedel erhölls genom elektrokemiska tester i citronsyra och artificiellt kranvatten. Resultaten visade att rostfritt stål 316L efter upprepad rengöring hade en högre benägenhet för gropkorrosion vid kontakt med artificiellt tappvatten (PDP). Skillnaden i den passiva ytoxidens elektrokemiska egenskaper hos det rengjorda rostfria stålet 316L var liten vid simulering av livsmedelskontakt (EIS).

    Fulltekst tilgjengelig fra 2024-04-30 13:05
  • 328.
    Feng, Ethan Y.
    et al.
    Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA, USA; BASIS Independent Silicon Valley High School, San Jose, CA, USA.
    Zelaya, Rosadriana
    Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA, USA.
    Holm, Alexander
    Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA, USA.
    Yang, An-Chih
    Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA, USA.
    Cargnello, Matteo
    Department of Chemical Engineering and SUNCAT Center for Interface Science and Catalysis, Stanford University, Stanford, CA, USA.
    Investigation of the optical properties of uniform platinum, palladium, and nickel nanocrystals enables direct measurements of their concentrations in solution2020Inngår i: Colloids and Surfaces A: Physicochemical and Engineering Aspects, ISSN 0927-7757, E-ISSN 1873-4359, Vol. 601, artikkel-id 125007Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Colloidal transition metal nanocrystals have gained increased interest in several fields because of the fascinating structural, optical, and catalytic properties obtained at the nanoscale. A thorough and systematic understanding of their characteristics could prove beneficial for different applications. Among these characteristics, the optical properties of colloidal nanoparticles are especially of interest due to the intriguing features that emerge at sub-wavelength scales, such as surface plasmon resonance. However, most research in this domain has focused on metals with absorption maxima in the visible light range, while the optical characteristics of other species remain relatively less studied. Therefore, in this work, we report on the optical properties of uniform platinum, palladium, and nickel nanocrystals, which are widely used in fields from sensors to catalysis, yet, with regard to their optical properties, remain largely uninvestigated. In particular, we measure and analyze their extinction coefficients, showing a size-dependence that can be rationalized with simple equations that relate light absorption to the diameter of the particles. The comprehension of this relationship enables a simple, time-efficient, and accurate method to measure the concentrations of metallic nanoparticles in solution with UV-vis spectroscopy, a useful property which facilitates the preparation of materials based on these colloidal nanoparticles for further research.

  • 329.
    Feng, Wenting
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Klaminder, Jonatan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och geovetenskap.
    Boily, Jean-Francois
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Thermal Stability of Goethite-Bound Natural Organic Matter Is Impacted by Carbon Loading2015Inngår i: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 119, nr 51, s. 12790-12796Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 330.
    Fernandes, Ricardo Madeira F.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi. University of Porto, Portugal.
    Buzaglo, M.
    Regev, O.
    Furó, Istvan
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Marques, E. F.
    Mechanical agitation induces counterintuitive aggregation of pre-dispersed carbon nanotubes2017Inngår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 493, s. 398-404Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 331.
    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 (2017-2019), Biovetenskap och material, Kemi och material. KTH Royal Institute of Technology, Sweden.
    Odnevall Wallinder, I.
    KTH Royal Institute of Technology, Sweden.
    Antibacterial silver nanocluster/silica composite coatings on stainless steel2017Inngår i: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 396, s. 1546-1555Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 332.
    Ferro, Lorenza
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Gentili, Francesco G.
    Funk, Christiane
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Isolation and characterization of microalgal strains for biomass production and wastewater reclamation in Northern Sweden2018Inngår i: Algal Research, ISSN 2211-9264, Vol. 32, s. 44-53Artikkel i tidsskrift (Fagfellevurdert)
    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 Desmodesmus, Scenedesmus 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 Coelastrella sp. 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 Coelastrella strain 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).

  • 333.
    Filippov, Andrei
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Soenen, Hilde
    Nynas NV, B-2020 Antwerp, Belgium.
    Blom, Johan
    Univ Antwerp, Fac Appl Engn, EMIB Res Grp, B-2020 Antwerp, Belgium.
    Antzutkin, Oleg N.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Dynamics and Structure of a Bitumen Emulsion as Studied by 1H NMR Diffusometry2023Inngår i: ACS Omega, E-ISSN 2470-1343, Vol. 8, nr 39, s. 36534-36542Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Self-diffusion in a bitumen emulsion was studied by H-1 NMR. The emulsion forms two phases: continuous and dispersed. The continuous aqueous phase contains mainly water, with the energy of activation of the diffusion process equal to that of bulk water, while its diffusivity is smaller than that of bulk water by a factor of 2. The dispersed phase consists of bitumen droplets containing confined water, whose dynamics is characterized by a fully restricted diffusion regime in cavities with sizes of similar to 0.11 mu m. Therefore, the studied bitumen emulsion can be described by a model of a complex multiple emulsion of the water/oil/water (WOW) type. The suggested model does agree well with data from H-1 NMR spectroscopy and diffusometry of the bitumen emulsion doped with paramagnetic MnSO4(aq) as well as with an additional H-1 NMR study of the emulsion structure, in which emulsion stability was compromised by freezing at 253 K.

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  • 334.
    Fischer, Andreas
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Chlordiazepoxide dichloromethane monosolvate2012Inngår i: Acta Crystallographica Section E: Structure Reports Online, E-ISSN 1600-5368Artikkel i tidsskrift (Fagfellevurdert)
    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.

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  • 335. Florén, Anders
    et al.
    Mäger, Imre
    Langel, Ülo
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för neurokemi. Tartu University, Estonia.
    Uptake kinetics of cell-penetrating peptides2011Inngår i: Cell-penetrating peptides: Methods and Protocols, Humana Press, 2011, s. 117-128Kapittel i bok, del av antologi (Fagfellevurdert)
    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.

  • 336.
    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 (Annet (populærvitenskap, debatt, mm))
    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.

  • 337.
    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 (Annet (populærvitenskap, debatt, mm))
    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.

  • 338.
    Forsberg, Diana Carolina Reyes
    et al.
    MoRe Research AB, Örnsköldsvik, Sweden.
    Sundman, Ola
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    On the importance of variation of alkalisation conditions on cellulose ether synthesis2022Inngår i: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 56, nr 3-4, s. 227-238Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    With a multivariate approach, we investigate and correlate the effect of mercerization conditions on the properties of a cellulose ether. We have chosen to work with carboxymethylcellulose (CMC) for analytical reasons. As expected, the DS was found to increase when the NaOH/AGU (anhydroglucose unit) stoichiometric ratio (r) was increased (range 1.0–1.3) and [NaOH] was decreased (range 50-30%). However, such changes also favoured the formation of unwanted side products. Decreased (r) and increased [NaOH] resulted in increased heterogeneity, and thus the quantities of insoluble particles and unreacted chemicals also increased. As another result, the prediction between mercerisation and synthesis weakens. Consequently, a DS of 0.18–0.7 was obtained; the measured solubility was much lower than expected. A non-statistical distribution of substituents was further found. Interestingly, the relative importance of substitution at increases with an increased [NaOH].

  • 339.
    Forslund, Mattias
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Claesson, Per M.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Pan, Jinshan
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Octadecanethiol as Corrosion Inhibitor for Zinc and Patterned Zinc-Copper in Humidified Air with Formic Acid2014Inngår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 161, nr 6, s. C330-C338Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 340.
    Forslund, Mattias
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Leygraf, Christofer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Claesson, Per Martin
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Lin, C.
    Pan, Jinshan
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Micro-galvanic corrosion effects on patterned copper-zinc samples during exposure in humidified air containing formic acid2013Inngår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 160, nr 9, s. C423-C431Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 341.
    Fredriksson, Felicia
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Analysis of fluoroalkyl sulfonamide (FASA) based copolymers: An indirect source of non-polymeric PFAS2023Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Per- and polyfluoroalkyl substances (PFAS) are an extensive group of anthropogenic compounds and are of global concern due to their negative effects on the environment and humans. Most environmental research reports non-polymeric PFAS, leading to a scarce understanding of polymeric PFAS, despite their large share on the global market.

    In this thesis, two fluoroalkyl sulfonamide (FASA)-based copolymers were studied to gain knowledge regarding their chemical characterization, occurrence, and fate. The main objectives were to provide analytical methods to analyze the FASA-based copolymers in sludge in relation to non-polymeric PFAS and extractable organo-fluorine (EOF) and to study their fate to the arable land when sludge is used as a fertilizer.

    The results revealed that the FASA-based copolymers were present in all sludge samples and their levels contributed to between 2 and 6 % of the total PFAS. Using two complementary extraction methods, both polymeric and non-polymeric PFAS were captured. However, more than 90% of the EOF belongs to unidentified origin. These results indicate the importance of extending the analysis of polymeric PFAS in environmental research.

    Further, elevated levels in sludge-amended soil of the C8-FASA-based copolymer were seen, illustrating sludge to be a potential source of C8-FASA-based copolymer to the environment. Both copolymers were transformed into non-polymeric PFAS in earthworms. This thesis provides evidence that these FASA-based copolymers are of concern, both as a direct emission and indirect source of non-polymeric PFAS to the environment.

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  • 342.
    Fredriksson, Felicia
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Eriksson, Ulrika
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Kärrman, Anna
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Yeung, Leo W. Y.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Impact of sample treatment on extractable organofluorine mass balance in sludge – an insight into the characteristics of unidentified organofluorineManuskript (preprint) (Annet vitenskapelig)
  • 343.
    Fredriksson, Felicia
    et al.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Kärrman, Anna
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Eriksson, Ulrika
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Yeung, Leo W. Y.
    Örebro universitet, Institutionen för naturvetenskap och teknik.
    Experimental and field studies of bioavailability and transformation of fluoroalkyl sulfonamide (FASA) based copolymers in earthwormsManuskript (preprint) (Annet vitenskapelig)
  • 344.
    Fredriksson, Mårten
    Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för ingenjörsvetenskap och fysik (from 2013).
    Syftet med NTA i kemi: Fjärdeklasselevers uppfattning av syftet jämfört med lärarens syfte2018Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Syftet med min undersökning var att bidra med ökade kunskaper om vilka uppfattningar som finns bland fjärdeklasselever gällande syftet med NTA i kemi, och om dessa överensstämmer med lärarens syfte. Datainsamlingen har gjorts via gruppintervjuer med femton elever och deras lärare. Intervjusvaren har sedan kategoriserats induktivt. Resultatet har visat att eleverna inte uppfattar syftet med NTA-lådan så som läraren tänkt. Det verkar som att eleverna ser ett mer närliggande syfte och fokuserar på vad som händer. Läraren, å andra sidan, tycks ha ett mer övergripande syfte som utgår från kunskapskraven men som hon inte fullt ut lyckas kommunicera till eleverna. Hon syftar även till att eleverna utvecklar sin resonemangsförmåga genom diskussioner i helklass. Eleverna tycker dessutom att helkassdiskussionerna är intressanta och lärorika. Tid läggs på diskussionerna vilket ger en möjlighet till en naturvetenskaplig literacitet.

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  • 345.
    Freitag, Marina
    et al.
    Uppsala Univ, Dept Chem Angstrom Lab, Sweden..
    Quentin, Daniel
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    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, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi. 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 conductor2015Inngår i: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 8, nr 9, s. 2634-2637Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 346.
    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 Process2011Inngår i: Journal of Chemical and Engineering Data, ISSN 0021-9568, E-ISSN 1520-5134, Vol. 56, nr 12, s. 4282-4290Artikkel i tidsskrift (Fagfellevurdert)
    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)]

  • 347.
    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 scoring2009Inngår i: ChemMedChem, ISSN 1860-7179, E-ISSN 1860-7187, Vol. 4, nr 8, s. 1317-1326Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 348. Friedman, Ran
    et al.
    Caflisch, A
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Pepsinogen-like activation intermediate of plasmepsin II revealed by molecular dynamics analysis2008Inngår i: Proteins: Structure, Function, and Bioinformatics, ISSN 0887-3585, E-ISSN 1097-0134, Vol. 73, nr 4, s. 814-827Artikkel i tidsskrift (Fagfellevurdert)
  • 349.
    Friedman, Ran
    et al.
    University of Zürich, Switzerland.
    Caflisch, A.
    The Protonation State of the Catalytic Aspartates in Plasmepsin II2007Inngår i: FEBS Letters, ISSN 0014-5793, E-ISSN 1873-3468, Vol. 581, s. 4120-4124Artikkel i tidsskrift (Fagfellevurdert)
  • 350. Fronzoni, Giovanna
    et al.
    Baseggio, Oscar
    Stener, Mauro
    Hua, Weijie
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Tian, Guangjun
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Luo, Yi
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi. 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 coronene2014Inngår i: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 141, nr 4, s. 044313-Artikkel i tidsskrift (Fagfellevurdert)
    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.

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