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  • 301.
    Hamberg, Anders
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry.
    Magnusson, Anders
    KTH, School of Biotechnology (BIO), Biochemistry.
    Hu, Francis J.
    KTH, School of Biotechnology (BIO), Biochemistry.
    Hult, Karl
    KTH, School of Biotechnology (BIO), Biochemistry.
    Selective Monoacylation of Diols by Substrate Assisted Catalysis in T40A Candida antarctica Lipase B2013In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 5, no 3, p. 743-747Article in journal (Refereed)
    Abstract [en]

    The selectivity towards diols over monoesters in the esterification of diols catalysed by lipase B from Candida antarctica (CALB) was improved by the single point mutation T40A in the enzyme's oxyanion hole. Substrate-assisted catalysis was suggested from molecular modelling of the tetrahedral intermediate in esterification of 1,2-ethanediol catalysed by T40A CALB. The non-reacting hydroxyl group of the diol forms a hydrogen bond to the oxyanion in the transition state, replacing that deleted in mutation. Monoester yields in transacylation reactions were monitored over time to compare the selectivities for wild-type and T40A CALB. The results showed increased selectivities towards the diols tested over their corresponding monoesters as a result of the T40A mutation with substrate-assisted catalysis as a plausible explanation.

  • 302.
    Hamedi, Mahiar M.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hajian, Alireza
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Fall, Andreas B.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Håkansson, Karl
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Salajkova, Michaela
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Lundell, Fredrik
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Highly Conducting, Strong Nanocomposites Based on Nanocellulose-Assisted Aqueous Dispersions of Single-Wall Carbon Nanotubes2014In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 8, no 3, p. 2467-2476Article in journal (Refereed)
    Abstract [en]

    It is challenging to obtain high-quality dispersions of single-wall nanotubes (SWNTs) in composite matrix materials, in order to reach the full potential of mechanical and electronic properties. The most widely used matrix materials are polymers, and the route to achieving high quality dispersions of SWNT is mainly chemical functionalization of the SWNT. This leads to increased cost, a loss of strength and lower conductivity. In addition full potential of colloidal self-assembly cannot be fully exploited in a polymer matrix. This may limit the possibilities for assembly of highly ordered structural nanocomposites. Here we show that nanofibrillated cellulose (NFC) can act as an excellent aqueous dispersion agent for as-prepared SWNTs, making possible low-cost exfoliation and purification of SWNTs with dispersion limits exceeding 40 wt %. The NFC:SWNT dispersion may also offer a cheap and sustainable alternative for molecular self-assembly of advanced composites. We demonstrate semitransparent conductive films, aerogels and anisotropic microscale fibers with nanoscale composite structure. The NFC:SWNT nanopaper shows increased strength at 3 wt % SWNT, reaching a modulus of 133 GPa, and a strength of 307 MPa. The anisotropic microfiber composites have maximum conductivities above 200 S cm(-1) and current densities reaching 1400 A cm(-2).

  • 303.
    Hamnevik, Emil
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Blikstad, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Norrehed, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Widersten, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Kinetic characterization of Rhodococcus ruber DSM 44541 alcohol dehydrogenase A2014In: Journal of Molecular Catalysis B: Enzymatic, ISSN 1381-1177, E-ISSN 1873-3158, Vol. 99, p. 68-78Article in journal (Refereed)
    Abstract [en]

    An increasing interest in biocatalysis and the use of stereoselective alcohol dehydrogenases in synthetic asymmetric catalysis motivates detailed studies of potentially useful enzymes such as alcohol dehydrogenase A (ADH-A) from Rhodococcus ruber. This enzyme is capable of catalyzing enantio-, and regioselective production of phenyl-substituted α-hydroxy ketones (acyloins) which are precursors for the synthesis of a range of biologically active compounds. In this study, we have determined the enzyme activity for a selection of phenyl-substituted vicinal diols and other aryl- or alkyl-substituted alcohols and ketones. In addition, the kinetic mechanism for the oxidation of (R)- and (S)-1-phenylethanol and the reduction of acetophenone has been identified as an Iso Theorell-Chance (hit and run) mechanism with conformational changes of the enzyme-coenzyme binary complexes as rate-determining for the oxidation of (S)-1-phenylethanol and the reduction of acetophenone. The underlying cause of the 270-fold enantiopreference for the (S)-enantiomer of 1-phenylethanol has been attributed to non-productive binding of the R-enantiomer. We have also shown that it is possible to tune the direction of the redox chemistry by adjusting pH with the oxidative reaction being favored at pH values above 7.

  • 304. Han, Kai
    et al.
    Wang, Mei
    Zhang, Shuai
    Wu, Suli
    Yang, Yong
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Photochemical hydrogen production from water catalyzed by CdTe quantum dots/molecular cobalt catalyst hybrid systems2015In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 51, no 32, p. 7008-7011Article in journal (Refereed)
    Abstract [en]

    A hybrid system with a coordinative interaction between a cobalt complex of a N2S2-tetradentate ligand and CdTe quantum dots displayed a high activity (initial TOF 850 h(-1)) and improved stability (TON 1.44 x 10(4) based on catalyst over 30 h) for the photochemical H-2 generation from water, with a quantum efficiency of 5.32% at 400 nm.

  • 305. Hansson, Petra M.
    et al.
    Claesson, Per M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Swerin, Agne
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Briscoe, Wuge H.
    Schoelkopf, Joachim
    Gane, Patrick A. C.
    Thormann, Esben
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Frictional forces between hydrophilic and hydrophobic particle coated nanostructured surfaces2013In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 15, no 41, p. 17893-17902Article in journal (Refereed)
    Abstract [en]

    Friction forces have long been associated with the famous Amontons' rule that states that the friction force is linearly dependent on the applied normal load, with the proportionality constant being known as the friction coefficient. Amontons' rule is however purely phenomenological and does not in itself provide any information on why the friction coefficient is different for different material combinations. In this study, friction forces between a colloidal probe and nanostructured particle coated surfaces in an aqueous environment exhibiting different roughness length scales were measured by utilizing the atomic force microscope (AFM). The chemistry of the surfaces and the probe was varied between hydrophilic silica and hydrophobized silica. For hydrophilic silica surfaces, the friction coefficient was significantly higher for the particle coated surfaces than on the flat reference surface. All the particle coated surfaces exhibited similar friction coefficients, from which it may be concluded that the surface geometry, and not the roughness amplitude per se, influenced the measured friction. During measurements with hydrophobic surfaces, strong adhesive forces related to the formation of a bridging air cavity were evident from both normal force and friction force measurements. In contrast to the frictional forces between the hydrophilic surfaces, the friction coefficient for hydrophobic surfaces was found to depend on the surface structure and we believe that this dependence is related to the restricted movement of the three-phase line of the bridging air cavity. For measurements using a hydrophobic surface and a hydrophilic probe, the friction coefficient was significantly smaller compared to the two homogeneous systems. A layer of air or air bubbles on the hydrophobic surface working as a lubricating layer is a possible mechanism behind this observation.

  • 306.
    Hansson, Petra M
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Claesson, Per Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Swerin, Agne
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Schoelkopf, Joachim
    Gane, Patrick A. C.
    Thormann, Esben
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Frictional forces between hydrophilic and hydrophobic particle coated nanostructured surfacesManuscript (preprint) (Other academic)
  • 307.
    Hansson, Petra M.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Hormozan, Yashar
    KTH, School of Information and Communication Technology (ICT), Material Physics.
    Brandner, Birgit D.
    Linnros, Jan
    KTH, School of Information and Communication Technology (ICT), Material Physics.
    Claesson, Per Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Swerin, Agne
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Schoelkopf, Joachim
    Gane, Patrick A. C.
    Thormann, Esben
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Hydrophobic pore array surfaces: Wetting and interaction forces in water/ethanol mixtures2013In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 396, p. 278-286Article in journal (Refereed)
    Abstract [en]

    Interactions between and wetting behavior of structured hydrophobic surfaces using different concentrations of water/ethanol mixtures have been investigated. Silica surfaces consisting of pore arrays with different pore spacings and pore depths were made hydrophobic by silanization. Their static and dynamic contact angles were found to be independent of the pore depth while fewer pores on the surface, i.e. a closer resemblance to a flat surface, gave a lower contact angle. As expected, a higher amount of ethanol facilitated wetting on all the surfaces tested. Confocal Raman microscopy measurements proved both water and ethanol to penetrate into the pores. AFM colloidal probe force measurements clearly showed that formation of air cavitation was hindered between the hydrophobic surfaces in presence of ethanol, and an increase in ethanol concentration was followed by a smaller jump-in distance and a weaker adhesion force. On separation, an immediate jump-out of contact occurred. The measured forces were interpreted as being due to capillary condensation of ethanol between the surfaces giving rise to very unstable cavities immediately rupturing on surface separation.

  • 308. Hao, Shuwei
    et al.
    Shang, Yunfei
    Li, Deyang
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Yang, Chunhui
    Chen, Guanying
    Enhancing dye-sensitized solar cell efficiency through broadband near-infrared upconverting nanoparticles2017In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 9, no 20, p. 6711-6715Article in journal (Refereed)
    Abstract [en]

    The inability to utilize near infrared (NIR) light has posed a stringent limitation for the efficiencies of most single-junction photovoltaic cells such as dye-sensitized solar cells (DSSCs). Here, we describe a strategy to alleviate the NIR light harvesting problem by upconverting non-responsive NIR light in a broad spectral range (over 190 nm, 670-860 nm) to narrow solar-cell-responsive visible emissions through incorporated dye-sensitized upconversion nanoparticles (DSUCNPs). Unlike typically reported UCNPs with narrow and low NIR absorption, the organic dyes (IR783) anchored on the DSUCNP surface were able to harvest NIR photons broadly and efficiently, and then transfer the harvested energy to the inorganic UCNPs (typically reported), entailing an efficient visible upconversion. We show that the incorporation of DSUCNPs into the TiO2 photoanode of a DSSC is able to elevate its efficiency from 7.573% to 8.568%, enhancing the power conversion efficiency by about 13.1%. We quantified that among the relative efficiency increase, 7.1% arose from the contribution of broad-band upconversion in DSUCNPs (about similar to 3.4 times higher than the highest previously reported value of similar to 2.1%), and 6.0% mainly from the scattering effect of DSUCNPs. Our strategy has immediate implications for the use of DSUCNPs to improve the performance of other types of photovoltaic devices.

  • 309.
    Hao, Yan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Yang, Wenxing
    Uppsala Univ, Dept Chem, Angstrom Lab, Phys Chem, SE-75120 Uppsala, Sweden.;Emory Univ, Dept Chem, 1515 Dickey Dr NE, Atlanta, GA 30322 USA..
    Karlsson, Karl Martin
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Cong, Jiayan
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Wang, Shihuai
    Uppsala Univ, Dept Chem, Angstrom Lab, Phys Chem, SE-75120 Uppsala, Sweden..
    Lo, Xing
    East China Univ Sci & Technol, Inst Fine Chem, Sch Chem & Mol Engn, Key Lab Adv Mat, Shanghai 200237, Peoples R China..
    Xu, Bo
    Uppsala Univ, Dept Chem, Angstrom Lab, Phys Chem, SE-75120 Uppsala, Sweden..
    Hua, Jianli
    East China Univ Sci & Technol, Inst Fine Chem, Sch Chem & Mol Engn, Key Lab Adv Mat, Shanghai 200237, Peoples R China..
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD.
    Boschloo, Gerrit
    Uppsala Univ, Dept Chem, Angstrom Lab, Phys Chem, SE-75120 Uppsala, Sweden..
    Efficient Dye-Sensitized Solar Cells with Voltages Exceeding 1 V through Exploring Tris(4-alkoxyphenyl)amine Mediators in Combination with the Tris(bipyridine) Cobalt Redox System2018In: ACS ENERGY LETTERS, ISSN 2380-8195, Vol. 3, no 8, p. 1929-1937Article in journal (Refereed)
    Abstract [en]

    Tandem redox electrolytes, prepared by the addition of a tris(p-anisyl)amine mediator into classic tris(bipyridine)cobalt-based electrolytes, demonstrate favorable electron transfer and reduced energy loss in dye-sensitized solar cells. Here, we have successfully explored three tris(4-alkoxyphenyl)-amine mediators with bulky molecular structures and generated more effective tandem redox systems. This series of tandem redox electrolytes rendered solar cells with very high photovoltages exceeding 1 V, which approaches the theoretical voltage limit of tris(bipyridine)cobalt-based electrolytes. Solar cells with power conversion efficiencies of 9.7-11.0% under 1 sun illumination were manufactured. This corresponds to an efficiency improvement of up to 50% as compared to solar cells based on pure tris(bipyridine)cobalt-based electrolytes. The photovoltage increases with increasing steric effects of the tris(4-alkoxyphenyl)amine mediators, which is attributed to a retarded recombination kinetics. These results highlight the importance of structural design for optimized charge transfer at the sensitized semiconductor/electrolyte interface and provide insights for the future development of efficient dye-sensitized solar cells.

  • 310.
    Harczuk, Ignat
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Nagy, B.
    Jensen, F.
    Vahtras, Olav
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Siberian Federal University, Russian Federation.
    Local decomposition of imaginary polarizabilities and dispersion coefficients2017In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, no 30, p. 20241-20250Article in journal (Refereed)
    Abstract [en]

    We present a new way to compute the two-body contribution to the dispersion energy using ab initio theory. By combining the complex polarization propagator method and the LoProp transformation, local contributions to the Casimir-Polder interaction is obtained. The full dispersion energy in dimer systems consisting of pairs of molecules including H2, N2, CO, CH4, pyridine, and benzene is investigated, where anisotropic as well as isotropic models of dispersion are obtained using a decomposition scheme for the dipole-dipole polarizability. It is found that the local minima structure of the π-cloud stacking of the benzene dimer is underestimated by the total molecular dispersion, but is alleviated by the inclusion of atomic interactions via the decomposition scheme. The dispersion energy in the T-shaped benzene dimer system is greatly underestimated by all dispersion models, as compared to high-level quantum calculations. The generalization of the decomposition scheme to higher order multipole polarizability interactions, representing higher order dispersion coefficients, is briefly discussed. It is argued that the incorporation of atomic C6 coefficients in new atomic force fields may have important ramifications in molecular dynamics studies of biomolecular systems.

  • 311.
    Hatamie, Amir
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Shahid Chamran University, Iran.
    Khan, Azam
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology. NED University of Engn and Technology, Pakistan.
    Golabi, Mohsen
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Beni, Valerio
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Mak, Wing Cheung
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Sadollah Khani, Azar
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology. Shahid Chamran University, Iran.
    Alnoor, Hatim
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Zargar, Behrooz
    Shahid Chamran University, Iran.
    Bano, Sumaira
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Zinc Oxide Nanostructure-Modified Textile and Its Application to Biosensing, Photocatalysis, and as Antibacterial Material2015In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 31, no 39, p. 10913-10921Article in journal (Refereed)
    Abstract [en]

    Recently, one-dimensional nanostructures with different morphologies (such as nanowires, nanorods (NRs), and nanotubes) have become the focus of intensive research, because of their unique properties with potential applications. Among them, zinc oxide (ZnO) nanomaterials has been found to be highly attractive, because of the remarkable potential for applications in many different areas such as solar cells, sensors, piezoelectric devices, photodiode devices, sun screens, antireflection coatings, and photocatalysis. Here, we present an innovative approach to create a new modified textile by direct in situ growth of vertically aligned one-dimensional (1D) ZnO NRs onto textile surfaces, which can serve with potential for biosensing, photocatalysis, and antibacterial applications. ZnO NRs were grown by using a simple aqueous chemical growth method. Results from analyses such as X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed that the ZnO NRs were dispersed over the entire surface of the textile. We have demonstrated the following applications of these multifunctional textiles: (1) as a flexible working electrode for the detection of aldicarb (ALD) pesticide, (2) as a photo catalyst for the degradation of organic molecules (i.e., Methylene Blue and Congo Red), and (3) as antibacterial agents against Escherichia coli. The ZnO-based textile exhibited excellent photocatalytic and antibacterial activities, and it showed a promising sensing response. The combination of sensing, photo catalysis, and antibacterial properties provided by the ZnO NRs brings us closer to the concept of smart textiles for wearable sensing without a deodorant and antibacterial control. Perhaps the best known of the products that is available in markets for such purposes are textiles with silver nanoparticles. Our modified textile is thus providing acceptable antibacterial properties, compared to available commercial modified textiles.

  • 312.
    Hatton, Fiona L.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Ruda, M.
    Lansalot, M.
    D'Agosto, F.
    Malmström, Eva
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Carlmark, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Xyloglucan-Functional Latex Particles via RAFT-Mediated Emulsion Polymerization for the Biomimetic Modification of Cellulose2016In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 17, no 4, p. 1414-1424Article in journal (Refereed)
    Abstract [en]

    Herein, we report a novel class of latex particles composed of a hemicellulose, xyloglucan (XG), and poly(methyl methacrylate) (PMMA), specially designed to enable a biomimetic modification of cellulose. The formation of the latex particles was achieved utilizing reversible addition-fragmentation chain transfer (RAFT) mediated surfactant-free emulsion polymerization employing XG as a hydrophilic macromolecular RAFT agent (macroRAFT). In an initial step, XG was functionalized at the reducing chain end to bear a dithioester. This XG macroRAFT was subsequently utilized in water and chain extended with methyl methacrylate (MMA) as hydrophobic monomer, inspired by a polymerization-induced self-assembly (PISA) process. This yielded latex nanoparticles with a hydrophobic PMMA core stabilized by the hydrophilic XG chains at the corona. The molar mass of PMMA targeted was varied, resulting in a series of stable latex particles with hydrophobic PMMA content between 22 and 68 wt % of the total solids content (5-10%). The XG-PMMA nanoparticles were subsequently adsorbed to a neutral cellulose substrate (filter paper), and the modified surfaces were analyzed by FT-IR and SEM analyses. The adsorption of the latex particles was also investigated by quartz crystal microbalance with dissipation monitoring (QCM-D), where the nanoparticles were adsorbed to negatively charged model cellulose surfaces. The surfaces were analyzed by atomic force microscopy (AFM) and contact angle (CA) measurements. QCM-D experiments showed that more mass was adsorbed to the surfaces with increasing molar mass of the PMMA present. AFM of the surfaces after adsorption showed discrete particles, which were no longer present after annealing (160 °C, 1 h) and the roughness (Rq) of the surfaces had also decreased by at least half. Interestingly, after annealing, the surfaces did not all become more hydrophobic, as monitored by CA measurements, indicating that the surface roughness was an important factor to consider when evaluating the surface properties following particle adsorption. This novel class of latex nanoparticles provides an excellent platform for cellulose modification via physical adsorption. The utilization of XG as the anchoring molecule to cellulose provides a versatile methodology, as it does not rely on electrostatic interactions for the physical adsorption, enabling a wide range of cellulose substrates to be modified, including neutral sources such as cotton and bacterial nanocellulose, leading to new and advanced materials.

  • 313. He, Qinggang
    et al.
    Cheng, Xiao
    Wang, Ying
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Qiao, Ruimin
    Yang, Wanli
    Guo, Jinghua
    Electrochemical and spectroscopic characterization of a dicobalt macrocyclic Pacman complex in the catalysis of the oxygen reduction reaction in acid media2013In: Journal of Porphyrins and Phthalocyanines, ISSN 1088-4246, E-ISSN 1099-1409, Vol. 17, no 4, p. 252-258Article in journal (Refereed)
    Abstract [en]

    The dicobalt complex [Co-2(L-2)] of a Schiff-base pyrrole macrocycle adopts a Pacman structure in solution and the solid state and shows much greater catalytic activity and selectivity for the four-electron oxygen reduction reaction (ORR) than the mononuclear cobalt phthalocyanine (CoPc) counterpart. Soft X-ray absorption spectroscopy (XAS) shows that the Co center in Co-2(L-2) is of the same valence as mononuclear CoPc. However, the former complex shows higher unoccupied Co 3d density which is believed to be beneficial for electron transfers. Furthermore, the XAS data suggests that the crystal fields for Co-2(L-2) and CoPc are different, and that an interaction remains between two Co atoms in Co-2(L-2). DFT calculations imply that the sterically hindered, cofacial structure of the dicobalt complex is critical for the operation of the four-electron reaction pathway during the ORR.

  • 314. He, W
    et al.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Runoff Rates of Zinc - a Four-Year Field and Laboratory Study: American Society for Testing and Materials2002In: Outdoor Atmospheric Corrosion / [ed] Herbert E Townsend, ASTM International, 2002, p. 216-Chapter in book (Refereed)
  • 315.
    He, Yunjuan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Dobryden, Illia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Pan, Jinshan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Ahniyaz, Anwar
    RISE Res Inst Sweden, Div Biosci & Mat, SE-11486 Stockholm, Sweden..
    Deltin, Tomas
    PTE Coatings AB, Hammarsvagen 4, SE-59432 Gamleby, Sweden..
    Corkery, Robert W.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Claesson, Per M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Nano-scale mechanical and wear properties of a waterborne hydroxyacrylic-melamine anti-corrosion coating2018In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 457, p. 548-558Article in journal (Refereed)
    Abstract [en]

    Corrosion protection is commonly achieved by applying a thin polymer coating on the metal surface. Many studies have been devoted to local events occurring at the metal surface leading to local or general corrosion. In contrast, changes occurring in the organic coating after exposure to corrosive conditions are much less studied. In this article we outline how changes in the coating itself due to curing conditions, environmental and erosion effects can be investigated at the nanometer scale, and discuss how such changes would affect its corrosion protection performance. We focus on a waterborne hydroxyacrylic-melamine coating, showing high corrosion protection performance for carbon steel during long-term (approximate to 35 days) exposure to 0.1 M NaCl solution. The effect of curing time on the conversion of the crosslinking reaction within the coating was evaluated by fourier transform infrared spectroscopy (FTIR); the wetting properties of the cured films were investigated by contact angle measurement, and the corrosion resistance was studied by electrochemical impedance spectroscopy (EIS). In particular, coating nanomechanical and wear properties before and after exposure to 0.1 M NaCl, were evaluated by atomic force microscopy (AFM). Fiber-like surface features were observed after exposure, which are suggested to arise due to diffusion of monomers or low molecular weight polymers to the surface. This may give rise to local weakening of the coating, leading to local corrosion after even longer exposure times. We also find a direct correlation between the stick-slip spacing during shearing and plastic deformation induced in the surface layer, giving rise to topographical ripple structures on the nanometer length scale.

  • 316.
    Hedayati, Ali
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Lindgren, Robert
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Ash transformation during single-pellet combustion of agricultural biomass fuels – focus on K and P2018Conference paper (Refereed)
  • 317.
    Hedberg, Jonas
    et al.
    KTH Royal Institute of Technology, Sweden.
    Karlsson, Hanna L.
    Karolinska Institute, Sweden.
    Hedberg, Yolanda
    KTH Royal Institute of Technology, Sweden.
    Blomberg, Eva
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Life Science. KTH Royal Institute of Technology, Sweden.
    Odnevall Wallinder, Inger
    KTH Royal Institute of Technology, Sweden.
    The importance of extracellular speciation and corrosion of copper nanoparticles on lung cell membrane integrity2016In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 141, p. 291-300Article in journal (Refereed)
    Abstract [en]

    Copper nanoparticles (Cu NPs) are increasingly used in various biologically relevant applications and products, e.g., due to their antimicrobial and catalytic properties. This inevitably demands for an improved understanding on their interactions and potential toxic effects on humans. The aim of this study was to investigate the corrosion of copper nanoparticles in various biological media and to elucidate the speciation of released copper in solution. Furthermore, reactive oxygen species (ROS) generation and lung cell (A549 type II) membrane damage induced by Cu NPs in the various media were studied. The used biological media of different complexity are of relevance for nanotoxicological studies: Dulbecco's modified eagle medium (DMEM), DMEM+ (includes fetal bovine serum), phosphate buffered saline (PBS), and PBS + histidine. The results show that both copper release and corrosion are enhanced in DMEM+, DMEM, and PBS + histidine compared with PBS alone. Speciation results show that essentially no free copper ions are present in the released fraction of Cu NPs in neither DMEM+, DMEM nor histidine, while labile Cu complexes form in PBS. The Cu NPs were substantially more membrane reactive in PBS compared to the other media and the NPs caused larger effects compared to the same mass of Cu ions. Similarly, the Cu NPs caused much more ROS generation compared to the released fraction only. Taken together, the results suggest that membrane damage and ROS formation are stronger induced by Cu NPs and by free or labile Cu ions/complexes compared with Cu bound to biomolecules.

  • 318.
    Hedberg, Jonas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Lundin, Maria
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Lowe, Troy
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Blomberg, Eva
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Wold, Susanna
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Interactions between surfactants and silver nanoparticles of varying charge2012In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 369, no 1, p. 193-201Article in journal (Refereed)
    Abstract [en]

    The interaction between silvernanoparticles (Ag NPs) of different surface charge and surfactants relevant to the laundry cycle has been investigated to understand changes in speciation, both in and during transport from the washing machine. Ag NPs were synthesized to exhibit either a positive or a negative surface charge in solution conditions relevant for the laundry cycle (pH 10 and pH 7). These particles were characterized in terms of size and surface charge and compared to commercially laser ablated Ag NPs. The surfactants included anionic sodium dodecylbenzenesulfonate (LAS), cationic dodecyltrimethylammoniumchloride (DTAC) and nonionic Berol 266 (Berol). Surfactant–Ag NP interactions were studied by means of dynamic light scattering, Raman spectroscopy, zeta potential, and Quartz Crystal Microbalance. Mixed bilayers of CTAB and LAS were formed through a co-operative adsorption process on positively charged Ag NPs with pre-adsorbed CTAB, resulting in charge reversal from positive to negative zeta potentials. Adsorption of DTAC on negatively charged synthesized Ag NPs and negatively charged commercial Ag NPs resulted in bilayer formation and charge reversal. Weak interactions were observed for nonionic Berol with all Ag NPs via hydrophobic interactions, which resulted in decreased zeta potentials for Berol concentrations above its critical micelle concentration. Differences in particle size were essentially not affected by surfactant adsorption, as the surfactant layer thicknesses did not exceed more than a few nanometers. The surfactant interaction with the Ag NP surface was shown to be reversible, an observation of particular importance for hazard and environmental risk assessments.

  • 319.
    Hedberg, Y. S.
    et al.
    KTH Royal Institute of Technology, Sweden; Karolinska Institute, Sweden.
    Pradhan, S.
    KTH Royal Institute of Technology, Sweden.
    Cappellini, F.
    Karolinska Institute, Sweden.
    Karlsson, M. -E
    KTH Royal Institute of Technology, Sweden.
    Blomberg, Eva
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Life Science. KTH Royal Institute of Technology, Sweden.
    Karlsson, H. L.
    Karolinska Institute, Sweden.
    Odnevall Wallinder, I.
    KTH Royal Institute of Technology, Sweden.
    Hedberg, J. F.
    KTH Royal Institute of Technology, Sweden.
    Electrochemical surface oxide characteristics of metal nanoparticles (Mn, Cu and Al) and the relation to toxicity2016In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 212, p. 360-371Article in journal (Refereed)
    Abstract [en]

    Most metal nanoparticles (NPs), except noble metal NPs, rapidly form a thin surface oxide in ambient conditions. The protective properties of these oxides improve or worsen depending on the environment, e.g., the human lung. Several properties, including the chemical/electrochemical stability and defect density, determine the capacity of these surface oxides to hinder the bulk metal from further oxidation (corrosion). The aim of this study was to investigate whether electrochemical surface oxide characterization of non-functionalized base metal NPs of different characteristics (Al, Mn and Cu) can assist in understanding their bioaccessibility (metal release) in cell media (DMEM+) and their cytotoxic properties following exposure in lung epithelial (A549) cells. The composition and valence states of surface oxides of metal NPs and their electrochemical activity were investigated using an electrochemical technique based on a graphite paste electrode to perform cyclic voltammetry in buffer solutions and open circuit potential measurements in DMEM+. The electrochemical surface oxide characterization was complemented and verified by Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The open circuit potential trends in DMEM+ correlated well with metal release results in the same solution, and provided information on the kinetics of oxide dissolution in the case of Cu NPs. Extensive particle agglomeration in cell medium (DMEM+) was observed by means of photon-cross correlation spectroscopy for all metal NPs, with sedimentation taking place very quickly. As a consequence, measurements of the real dose of added non-functionalized metal NPs to cell cultures for cytotoxicity testing from a sonicated stock solution were shown necessary. The cytotoxic response was found to be strongly correlated to changes in physico-chemical and electrochemical properties of the surface oxides of the metal NPs, the most potent being Cu NPs, followed by Mn NPs. No cytotoxicity was observed for Al NPs. The electrochemical surface oxide characterization corresponded well with other tools commonly used for nanotoxicological characterization and provided additional information.

  • 320.
    Hedberg, Yolanda
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Stainless Steel in Biological Environments – Relation between Material Characteristics, Surface Chemistry and Toxicity2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Triggered by the regulatory need of the industry to demonstrate safe use of their alloy products from an environmental and health perspective, and by the significant lack of metal release data and its correlation to material and surface characteristics for iron- and chromium-based alloys, a highly interdisciplinary in-depth research effort was undertaken to assess the relation between material/surface characteristics and toxicity with main emphasis on stainless steel alloys. This thesis focuses predominantly on studies made on AISI 316L both as massive sheet and as powder particles, but includes also results for other stainless steel grades and reference metals and metal oxides.

     

    The work comprises multi-analytical bulk and surface characterizations combined with particle characterizations and corrosion investigations, all correlated with in-depth kinetic metal release (bioaccessibility) studies as a function of route of manufacture, powder particle characteristics, surface finish, stainless steel grade, solution composition, pH, acidity and complexation capacity, as well as the presence of proteins. Speciation (chemical form) measurements were in addition conducted of released chromium, and of metal species in the surface oxide. Protein interactions were investigated in terms of adsorption, protein-metal complexation both at the surface and in solution, and the relative strength of protein-stainless steel surface interaction was addressed. In vitro and in vivo toxicological studies were conducted for the same inert-gas-atomized 316L powder sized < 4µm.

     

    Bulk and surface oxide properties, such as phase, structure, morphology, chemical and electrochemical stability, protein-surface interactions, bioavailability of released metals, were all clearly evident to largely influence the metal release process and any induced toxicity. The route of manufacture was shown to strongly influence the bulk and surface oxide characteristics of stainless steel powders, hence also their electrochemical and catalytic properties, as well as the release/dissolution of metals from the powders (Papers VIII, XIII, XIV-XVII). The release of metals from both stainless steel sheets and powders was in general low compared to pure iron or nickel metal, and highly dependent on bulk and surface characteristics, the composition, complexation capacity and buffering capacity (and pH) of the solution, as well as on many experimental factors including time and sonication (Papers VI, VIII, XI, and XVII).

     

    Surface-protein interactions strongly enhanced the release of alloy constituents (Papers IX, XI, and XVII). Iron was preferentially released (manganese in the case of inert-gas-atomized stainless steel powders) (Papers VIII, XI, and XVII). Protein-stainless steel surface interactions were most probably governed by chemisorption at given experimental conditions (Papers XI-XII). A strong protein-adsorption was evident for all stainless steel surfaces investigated, independent of protein charge, size or structure (Paper IX). Protein-metal complexes were formed both at the surface and in solution (Papers X-XII). Differences in protein charge and type resulted in varying degrees of interaction with differences in the extent of enhanced metal release as a consequence (Papers XI-XII). The inert-gas-atomized stainless steel powder sized <4 µm induced neither any significant increase of lysis of erythrocytes (rupture of red blood cells) nor any cytotoxicity, but resulted in a slight DNA damage in in vitro toxicity measurements (Paper VI). No adverse effects were however observed in an in vivo 28-day repeated-dose inhalation study on rats using the same powder (Paper VII).

     

    The most important bulk, surface, particle, and experimental factors governing the bioaccessibility properties of stainless steel were identified and mechanistically elucidated. Detailed knowledge of all factors is essential for accurate hazard or risk assessment of metal alloys and enables read-across possibilities with materials of the same or similar characteristics. However, in cases where data is different from known systems for one factor or more, bioaccessibility data should be generated before any risk assessment is made.

  • 321.
    Hedberg, Yolanda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Dromberg, P.
    Water and Sewage Network Investigations, Stockholm Vatten VA AB.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Die Bindekapazität von Entwässerungssystemen für Kupfer von Kupferdächern: Vergleich von Regenwasserkupferkonzentrationen in einem Kupferdachentwässerungssystem und einem Parkplatz2010In: Wasser- /Abwassertechnik, Vol. 3, p. 22-23Article in journal (Other (popular science, discussion, etc.))
  • 322.
    Hedberg, Yolanda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Protective green patinas on copper in outdoor constructions2011In: Journal of Environmental Protection, ISSN 2152-2197, E-ISSN 2152-2219, Vol. 2, no 7, p. 956-959Article in journal (Refereed)
    Abstract [en]

    The last 15 years of research related to atmospheric corrosion and the release of copper to the environment are shortly summarized. Brown and green patinas with high barrier properties for corrosion are gradually evolved on copper at atmospheric conditions. The corrosion process and repeated dry and wet cycles results in a partial dissolution of cor-rosion products within the patina. Dissolved copper can be released and dispersed into the environment via the action of rainwater, however the major part is rearranged within the patina during drying cycles. The majority of corrosion products formed have a poor solubility, very different from water soluble copper salts. The release process is very slow and takes place independent of patina color. Its extent has only a marginal effect on the adherent patina. Released cop-per rapidly interacts with organic matter and in contact with different surfaces already in the close vicinity of the building, such as drainage systems, storm water pipes, pavements, stone materials and soil systems. These surfaces all have high capacities to retain copper in the runoff water and to reduce its concentration and chemical form to non-available and non-toxic levels for aquatic organisms.

  • 323.
    Hedberg, Yolanda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Transformation /dissolution studies on the release of iron and chromium from particles of alloys compared with their pure metals and selected metal oxides2012In: Materials and Corrosion, ISSN 0947-5117, Vol. 63, no 6, p. 481-491Article in journal (Refereed)
    Abstract [en]

    Transformation/dissolution (T/D) data for different Cr- and Fe-based alloys (a FeCr alloy, stainless steel AISI 316L, an alloy side product (SP) from stainless steel production) compared with their pure metals (Cr, Fe) and selected metal oxides (Cr2O3, Fe3O4) was generated and is used throughout the entire REACH assessment documentation of chromium metal and ferrochromium alloys to derive conclusions regarding their acute and chronic ecotoxicity hazard classification. Short and long term tests were conducted to assess data for acute and chronic aquatic toxicity following the recognized standardized T/D protocol. Tests were performed in media of different pH (pH 6.0 and pH 8.0), time periods, and solution composition, also investigating the effect of different experimental parameters. Generated data elucidates the complexity of the metal release process and its dependence on many interacting material-, surface-, and experimental factors as well as on the chemistry of the metalwater system being metal species specific. It is evident that the extent of metal release cannot be predicted by either the bulk or the surface composition, and that metal speciation measurements of released metals are essential to assess aquatic toxicity induced by metal/alloy particles. Observed released Fe and Cr concentrations were significantly lower than reported acute and chronic ecotoxicological endpoints.

  • 324.
    Hedberg, Yolanda S.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Hedberg, Jonas F.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Herting, Gunilla
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Goidanich, Sara
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Critical Review: Copper Runoff from Outdoor Copper Surfaces at Atmospheric Conditions2014In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 48, no 3, p. 1372-1381Article, review/survey (Refereed)
    Abstract [en]

    This review on copper runoff dispersed from unsheltered naturally patinated copper used for roofing and facades summarizes and discusses influencing factors, available literature, and predictive models, and the importance of fate and speciation for environmental risk assessment. Copper runoff from. outdoor surfaces is predominantly governed by electrochemical and chemical reactions and is highly dependent on given exposure conditions (size, inclination, geometry, degree of sheltering, and orientation), surface parameters (age, patina composition, and thickness), and site-specific environmental conditions (gaseous pollutants, chloride, rainfall characteristics (amount, intensity, pH), wind direction, temperature, time of wetness, season). The corrosion rate cannot be used to assess the runoff rate. The extent of released copper varies largely between different rain events and is related to dry and wet periods, dry deposition prior to the rain event and prevailing rain and patina characteristics. Interpretation and use of copper runoff data for environmental risk assessment and management need therefore to consider site-specific factors and focus on average data of long-term studies (several years). Risk assessments require furthermore that changes in copper speciation, bioavailability aspects, and potential irreversible retention on solid surfaces are considered, factors that determine the environmental fate of copper runoff from outdoor surfaces.

  • 325.
    Hedberg, Yolanda S.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Lidén, Carola
    Chromium(III) and chromium(VI) release from leather during 8 months of simulated use2016In: Contact Dermatitis, ISSN 0105-1873, E-ISSN 1600-0536, Vol. 75, no 2, p. 82-88Article in journal (Refereed)
    Abstract [en]

    Background. Chromium ( Cr) release from Cr-tanned leather articles is amajor cause of Cr contact dermatitis. It has been suggested that Cr( VI) release from leather is not necessarily an intrinsic property of the leather, but is strongly dependent on environmental conditions. Objectives. To test this hypothesis for long-term ( 8 months) simulated use. Materials and methods. The release of total Cr and Cr( VI) from Cr-tanned, unfinished leather was analysed in subsequent phosphate buffer ( pH 8.0) immersions for a period of 7.5 months. The effect of combined ultraviolet treatment and alkaline solution ( pH 12.1) was tested. Dry storage [ 20% relative humidity ( RH)] was maintained between immersions. Atomic absorption spectroscopy, X-ray fluorescence and diphenylcarbazide tests were used. Results. Cr( VI) release was dependent on previous dry storage or alkaline treatment, but not on duration or number of previous immersions. Cr(III) release decreased with time. Fifty-two percent of the total Cr released during the last immersion period was Cr( VI). Cr( VI) release exceeded 9 mg/kg in all immersion periods except in the first 10-day immersion ( 2.6mg/kg). Conclusions. Cr( VI) release is primarily determined by environmental factors ( RH prior to immersion, solution pH, and antioxidant content). The RH should be kept low prior to testing Cr( VI) release from leather.

  • 326.
    Hedberg, Yolanda S.
    et al.
    KTH Royal Institute of Technology, Sweden; Karolinska Institute, Sweden.
    Pettersson, Maria
    Uppsala University, Sweden.
    Pradhan, Sulena
    KTH Royal Institute of Technology, Sweden.
    Odnevall Wallinder, Inger
    KTH Royal Institute of Technology, Sweden.
    Rutland, Mark W.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Life Science. KTH Royal Institute of Technology, Sweden.
    Persson, Cecilia
    Uppsala University, Sweden.
    Can Cobalt(II) and Chromium(III) ions released from joint prostheses influence the friction coefficient?2015In: ACS Biomaterial Science and Engineering, E-ISSN 2373-9878, Vol. 1, no 8, p. 617-620Article in journal (Refereed)
    Abstract [en]

    Cobalt chromium molybdenum alloys (CoCrMo) are commonly used as articulating components in joint prostheses. In this tribocorrosive environment, wear debris and metal ionic species are released and interact with proteins, possibly resulting in protein aggregation. This study aimed to investigate whether this could have an effect on the friction coefficient in a typical material couple, namely CoCrMo-on-polyethylene. It was confirmed that both Co(II) and Cr(III) ions, and their combination, at concentrations relevant for the metal release situation, resulted in protein aggregation and its concomitant precipitation, which increased the friction coefficient. Future studies should identify the clinical importance of these findings.

  • 327.
    Hedberg, Yolanda
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Wei, Zheng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Chevez, Federico Moncada
    Natl Autonomous Univ Honduras, Dept Publ Hlth, Fac Med Sci, Tegucigalpa, Honduras.;Cent Amer Network Informat & Advice Ctr Toxicol R, Tegucigalpa, Honduras.;Ctr Res & Dev Hlth Labour & Environm CIDSTA, Tegucigalpa, Honduras..
    Chromium(III), chromium(VI) and cobalt release from leathers produced in Nicaragua2019In: Contact Dermatitis, ISSN 0105-1873, E-ISSN 1600-0536, Vol. 80, no 3, p. 149-155Article in journal (Refereed)
    Abstract [en]

    Background: Leather exposure has been associated with chromium (Cr) and cobalt (Co) contact dermatitis. Cr(VI) in leather is now restricted to < 3 mg/kg in the EU. Cr(III) is not restricted. Objectives: To analyse 29 differently coloured Cr-tanned leather samples from two Nicaraguan tanneries, and to compare their release of Cr, Cr(VI) and Co with that of leathers produced in Europe. Methods: Cr, Cr(VI) and Co were extracted in phosphate buffer for 3 hours at 25 degrees C according to EN ISO 17075. Atomic absorption spectroscopy and spectrophotometry were used for detection of the metals in phosphate buffer. Results: There was no difference in total Cr or Cr(VI) release between European and Nicaraguan leathers. There was no association between Cr(VI) and total Cr release. Co was released primarily from leathers of one tannery. Cr(III) was released in significantly higher amounts than Cr(VI). Conclusions: Future investigations and regulations should focus on Cr(III) and Co as well as on Cr(VI).

  • 328.
    Hellander, Stefan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computational Science.
    Hellander, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computational Science.
    Petzold, Linda
    University of California, Department of Computer Science.
    Mesoscopic-microscopic spatial stochastic simulation with automatic system partitioning2017In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 147, no 23, article id 234101Article in journal (Refereed)
    Abstract [en]

    The reaction-diffusion master equation (RDME) is a model that allows for efficient on-lattice simulation of spatially resolved stochastic chemical kinetics. Compared to off-lattice hard-sphere simulations with Brownian dynamics or Green's function reaction dynamics, the RDME can be orders of magnitude faster if the lattice spacing can be chosen coarse enough. However, strongly diffusion-controlled reactions mandate a very fine mesh resolution for acceptable accuracy. It is common that reactions in the same model differ in their degree of diffusion control and therefore require different degrees of mesh resolution. This renders mesoscopic simulation inefficient for systems with multiscale properties. Mesoscopic-microscopic hybrid methods address this problem by resolving the most challenging reactions with a microscale, off-lattice simulation. However, all methods to date require manual partitioning of a system, effectively limiting their usefulness as "black-box" simulation codes. In this paper, we propose a hybrid simulation algorithm with automatic system partitioning based on indirect a priori error estimates. We demonstrate the accuracy and efficiency of the method on models of diffusion-controlled networks in 3D.

  • 329.
    Hellström, Lisbeth
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Carlberg, Torbjörn
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Gradin, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Gregersen, Øyvind
    Department of chemical engineering, NTNU, Norway.
    Collimated chipping technology in order to reduce the energy consumption in mechanical pulping2011In: Proceeding for International Mechanical Pulping Conference, Xi'an, P.R. of China, 2011, p. 457-460Conference paper (Other academic)
    Abstract [en]

    It has recently been shown that it is possible to improve the energy efficiency during first stage TMP (thermomechanical pulp) refining by utilizing a modified chipping method (collimated chipping). A patent application regarding this method has been filed and is pending. The modification consists in that the spout angle i.e. the angle between the fibre direction of the wood specimen and the cutting plane, is increased. This paper reports the differences in properties of IMP refined from chips produced at two different spout angles i.e. 30 and 50 with and without the addition of sodium bisulphite (NaHSO3) to the dilution water. It was found that the specific energy input for a certain CSF (Canadian Standard Freeness) value was lower for chips produced at spout 50 but that the addition of chemicals to the dilution water had no influence on the specific energy value for a given CSF value. However, the tensile index and specific light scattering coefficient was substantially higher for handsheets made of the pulp refined from chips produced at spout angle 50 and with NaHSO3 added compared to handsheets from pulp made from 30 and 50 chips without chemicals added.

  • 330.
    Henriksson, Linda
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Structural and functional studies of a novel Botulinum neurotoxin and of MTH12018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    X-ray crystallography visualizes the three dimensional molecular structures of proteins at atomic resolution. Seeing the molecular structure of a biomedically interesting protein enables a higher understanding of its function. The process of producing pure protein from genetic material to generate crystals and determine the molecular structure can be a long and challenging process. My thesis involves structural and functional studies of two different proteins, which are both biomedically interesting and important to learn about. X-ray crystallography is the method which has been used to determine the majority of the protein structures that we know of today and is also the method used in the results presented in my thesis. 

    Today there are no cancer therapies defeating all types of cancers and they do not come without side effects. Battling cancer diseases often include long and painful treatments. Finding an anti-cancer drug targeting phenotypes characteristic of cancer cells is a compelling thought. MutT homolog-1 (MTH1) is an enzyme present in all proliferating cells. The enzyme seems to be crucial for cancer cell survival but not for the viability of normal cells. MTH1 cleans out oxidized and thereby damaged nucleotides from the free nucleotide pool and stops them from being used in DNA synthesis. This process is very important in fast proliferating cancer cells. The hypothesis is to inhibit MTH1 and thereby allow a limitless amount of DNA damage in the cancer cells. This action will eventually kill cancer cells while not affecting normal cells. The molecular structure of MTH1 with (PDB ID: 3ZR0) and without a product bound (PDB ID: 3ZR1) was determined and is presented in my thesis. These two structures aided in the synthesis of inhibitors. 

    Botulinum neurotoxins (BoNTs) are the most potent toxins known. As little as one gram of pure toxin could potentially kill one million people. Due to its potency BoNT is a potential  bioterrorism threat. The toxin is also a very potent drug used clinically to relieve the symptoms of an array of neuromuscular disorders. Most people know this neurotoxin by one of its commercial names: Botox™. Additionally BoNTs are the cause of botulism. BoNTs are neuro-specific enzymes that target neuromuscular signaling, inducing flaccid paralysis and potentially death. It is of importance to learn more about these toxins to enable the development of new countermeasures, vaccines or more efficient neuroparalytic drugs. BoNTs consist of three domains with different functions, all crucial for intoxication. The toxins are fragile and can easily be destroyed by harsh surroundings if not protected by non-toxic non-hemagglutinin (NTNH) proteins. The complex of some BoNT serotypes and their protective NTNH have proven to be pH-dependent. Parts of the intoxication process are not yet clear and their mechanisms are still puzzling researchers. Until recently seven BoNT serotypes were identified. We have now identified and characterized a novel serotype called BoNT/X. The molecular structure of the active domain is presented here (PDB ID: 6F47). The pH-dependent mechanism forming a complex as seen in other serotypes, is confirmed to be present in BoNT/X as well.

  • 331.
    Henschen, Jonatan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Illergård, Josefin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Larsson, Per
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Ek, Monica
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Wågberg, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Antibacterial surface modification of nanocellulosic materials2015In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 249Article in journal (Other academic)
  • 332.
    Hernell, Olle
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Den humana mjölkens lipaser: egenskaper och fysiologiska aspekter1974Doctoral thesis, comprehensive summary (Other academic)
    Abstract [sv]

    I avhandlingen visas att:

    1.  Human mjölk innehåller två lipaser. Det ena är ett serum-stimulerat lipas (lipoprotein lipas). Lipoprotein lipaser är enzymer som har en central roll i den normala katabolismen av de triglyceridrika plasma- lipoproteinerna. Lipaset har sannolikt inte någon fysiologisk funktion i mjölken. En metod beskrivs med vilken lipaset har renats ca 9 500 gånger från mjölk.

    2.  Det serum-stimulerade lipaset från human mjölk har de klassiska egen­skaperna för ett serum-stimulerat lipas (lipoprotein lipas). Med en immunologisk metod visas att lipaset korsreagerar med motsvarande lipaser i bovin mjölk och human postheparin plasma. Slutsatsen är att det serum-stimulerade lipaset i human mjölk är väl värt att studera eftersom det mycket väl kan ha många egenskaper gemensamma med de fysiologiskt aktiva och viktiga humana serum-stimulerade lipaserna.

    3.  Det andra lipaset i human mjölk, det gallsalt-stimulerade lipaset, har en låg substratspecificitet. Gallsalter stimulerar enzymaktiviteten mot alla substrat som testats. Mot mjölkens egna triglycerider är lipaset helt inaktivt i frånvaro av gallsalter. I närvaro av gall- salter spjälkar lipaset alla tre esterbindningarna i triglycerid- molekylen så att slutprodukterna blir fria fettsyror och glycerol.

    4.  Gallsalter skyddar lipaset mot olika typer av inaktivering, t ex mot inaktivering av tarmens proteinnedbrytande enzymer. Det är sanno­likt att gallsalternas effekt beror på att de direkt interagerar med enzymproteinet. Lipaset visas ha sådana egenskaper att det väsentligt skulle kunna bidraga till den spjälkning av mjölktriglyceriderna som sker i tarmen hos den nyfödde.

  • 333.
    Herting, Gunilla
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Jiang, Tao
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Sjöstedt, Carin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Release of Si from Silicon, a Ferrosilicon (FeSi) Alloy and a Synthetic Silicate Mineral in Simulated Biological Media2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 9, p. e107668-Article in journal (Refereed)
    Abstract [en]

    Unique quantitative bioaccessibility data has been generated, and the influence of surface/material and test media characteristics on the elemental release process were assessed for silicon containing materials in specific synthetic body fluids at certain time periods at a fixed loading. The metal release test protocol, elaborated by the KTH team, has previously been used for classification, ranking, and screening of different alloys and metals. Time resolved elemental release of Si, Fe and Al from particles, sized less than 50 mm, of two grades of metallurgical silicon (high purity silicon, SiHG, low purity silicon, SiLG), an alloy (ferrosilicon, FeSi) and a mineral (aluminium silicate, AlSi) has been investigated in synthetic body fluids of varying pH, composition and complexation capacity, simple models of for example dermal contact and digestion scenarios. Individual methods for analysis of released Si (as silicic acid, Si(OH)(4)) in synthetic body fluids using GF-AAS were developed for each fluid including optimisation of solution pH and graphite furnace parameters. The release of Si from the two metallurgical silicon grades was strongly dependent on both pH and media composition with the highest release in pH neutral media. No similar effect was observed for the FeSi alloy or the aluminium silicate mineral. Surface adsorption of phosphate and lactic acid were believed to hinder the release of Si whereas the presence of citric acid enhanced the release as a result of surface complexation. An increased presence of Al and Fe in the material (low purity metalloid, alloy or mineral) resulted in a reduced release of Si in pH neutral media. The release of Si was enhanced for all materials with Al at their outermost surface in acetic media.

  • 334.
    Herting, Gunilla
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Lindström, David
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science (closed 20081231).
    Multi-analytical investigation of stainless steel grade AISI 420 in simulated food contact2009In: Journal of Food Engineering, ISSN 0260-8774, E-ISSN 1873-5770, Vol. 93, no 1, p. 23-31Article in journal (Refereed)
    Abstract [en]

    Martensitic stainless steel grade AN 420 intended for cutlery knives and scissor blades has been investigated in all attempt to correlate microstructure and surface finish (polishing procedure) to metal release rates of the main alloy constituents, iron and chromium. Metallographic investigations proved the knife steel and, in particular the scissor steel to have very inhomogeneous microstructures. The knife steel contained bands of ferrite in the martensitic structure while the scissor steel revealed large amounts of tempered martensite and inclusions of manganese sulphides and silicon oxides. Samples of different surface finish were immersed in 3 vol% acetic acid at 40 degrees C from 1 to 10 days for metal release testing. simulating food contact. The largely inhomogeneous microstructure of the scissor steel results in high and greatly varying metal release rates. despite a fairly high chromium content Of the Surface oxide. Areas of inclusions seem to act as initiation points for accelerated metal release and the forming of a surface oxide depleted in chromium, but rich in copper. The generation Of high Surface temperatures during polishing was found beneficial from a metal release perspective as a result Of the formation of a surface oxide of improved passivating properties.

  • 335.
    Heydari, Golrokh
    et al.
    KTH Royal Institute of Technology, Sweden.
    Tyrode, Erik
    KTH Royal Institute of Technology, Sweden.
    Visnevskij, Ceslav
    Vilnius University, Lithuania.
    Makuska, Ricardas
    Vilnius University, Lithuania.
    Claesson, Per M.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Material och ytteknik. KTH Royal Institute of Technology, Sweden.
    Temperature-dependent deicing properties of electrostatically anchored branched brush layers of poly(ethylene oxide)2016In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 32, no 17, p. 4194-4202Article in journal (Refereed)
    Abstract [en]

    The hydration water of hydrophilic polymers freezes at subzero temperatures. The adsorption of such polymers will result in a hydrophilic surface layer that strongly binds water. Provided this interfacial hydration water remains liquidlike at subzero temperatures, its presence could possibly reduce ice adhesion, in particular, if the liquidlike layer is thicker than or comparable to the surface roughness. To explore this idea, a diblock copolymer, having one branched bottle-brush block of poly(ethylene oxide) and one linear cationic block, was electrostatically anchored on flat silica surfaces. The shear ice adhesion strength on such polymer-coated surfaces was investigated down to -25 °C using a homebuilt device. In addition, the temperature dependence of the ice adhesion on surfaces coated with only the cationic block, only the branched bottle-brush block, and with linear poly(ethylene oxide) was investigated. Significant ice adhesion reduction, in particular, at temperatures above -15 °C, was observed on silica surfaces coated with the electrostatically anchored diblock copolymer. Differential scanning calorimetry measurements on bulk polymer solutions demonstrate different thermal transitions of water interacting with branched and linear poly(ethylene oxide) (with hydration water melting points of about -18 and -10 °C, respectively). This difference is consistent with the low shear ice adhesion strength measured on surfaces carrying branched bottle-brush structured poly(ethylene oxide) at -10 °C, whereas no significant adhesion reduction was obtained with linear poly(ethylene oxide) at this temperature. We propose a lubrication effect of the hydration water bound to the branched bottle-brush structured poly(ethylene oxide), which, in the bulk, does not freeze until -18 °C.

  • 336.
    Hirn, A
    et al.
    Nordic Galvanizers Association, Stockholm.
    Odnevall Wallinder, Inger
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Varmförzinkat stål i samhället2008In: Ytforum, ISSN 0349-4470, Vol. 3, no 17Article in journal (Other (popular science, discussion, etc.))
  • 337.
    Hjalmarsson, Nicklas
    et al.
    KTH Royal Institute of Technology, Sweden.
    Atkin, Rob
    University of Newcastle, Australia.
    Rutland, Mark W.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Life Science. KTH Royal Institute of Technology, Sweden.
    Effect of Lithium ions on rheology and interfacial forces in Ethylammonium Nitrate and Ethanolammonium Nitrate2016In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 120, no 47, p. 26960-26967Article in journal (Refereed)
    Abstract [en]

    The effect of added Li+ to two ionic liquids (ILs), ethylammonium nitrate (EAN) and ethanolammonium nitrate (EtAN), has been investigated using rheology and colloidal probe atomic force microscopy (AFM). Rheology data revealed a complex viscosity dependence that can be ascribed to the different bulk nanostructures. AFM force curves revealed steps for the neat ILs, analogous to those in previous studies. The addition of Li+ broadened the steps, which is likely an effect of ion clusters formed. Friction measurements corroborate this data and also showed that the structure of EtAN is much more prone to change as Li+ is added. These results demonstrate the complex behavior of ILs on interfaces and the effect of perturbing such interactions. (Graph Presented).

  • 338.
    Hjalmarsson, Nicklas
    et al.
    KTH Royal Institute of Technology, Sweden.
    Wallinder, Daniel
    Attana AB, Sweden.
    Glavatskih, Sergei
    KTH Royal Institute of Technology, Sweden; Ghent University, Belgium.
    Atkin, Rob
    University of Newcastle, Australia.
    Aastrup, Teodor
    Attana AB, Sweden.
    Rutland, Mark W.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Life Science. KTH Royal Institute of Technology, Sweden.
    Weighing the surface charge of an ionic liquid2015In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 7, no 38, p. 16039-16045Article in journal (Refereed)
    Abstract [en]

    Electrochemical quartz crystal microbalance has been used to measure changes in the composition of the capacitive electrical double layer for 1-ethyl-3-methylimidazolium tris(pentafluoroethyl)-trifluorophosphate, an ionic liquid, in contact with a gold electrode surface as a function of potential. The mass difference between the cation and anion means that the technique can effectively "weigh" the surface charge accurately with high temporal resolution. This reveals quantitatively how changing the potential alters the ratio of cations and anions associated with the electrode surface, and thus the charge per unit area, as well as the kinetics associated with these interfacial processes. The measurements reveal that it is diffusion of co-ions into the interfacial region rather than expulsion of counterions that controls the relaxation. The measured potential dependent double layer capacitance experimentally validates recent theoretical predictions for counterion overscreening (low potentials) and crowding (high potentials) at electrode surfaces. This new capacity to quantitatively measure ion composition is critical for ionic liquid applications ranging from batteries, capacitors and electrodeposition through to boundary layer structure in tribology, and more broadly provides new insight into interfacial processes in concentrated electrolyte solutions.

  • 339.
    Hohn, Nuri
    et al.
    Tech Univ Munich, Lehrstuhl Funkt Mat, Dept Phys, James Franck Str 1, D-85748 Garching, Germany. chwartzkopf, Matthias; Roth, Stephan V..
    Shlosser, Steffen J.
    Biessmann, Lorenz
    Song, Lin
    Grott, Sebastian
    Xia, Senlin
    Wang, Kun
    Schwartzkopf, Matthias
    Roth, Stephan V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Mueller-Buschbaum, Peter
    Impact of Catalytic Additive on Spray Deposited and Nanoporous Titania in Films Observed via in Situ X-ray Scattering: Implications for hanced Photovoltaics2018In: ACS Applied Nano Materials, ISSN 2574-0970, Vol. 1, no 8, p. 4227-4235Article in journal (Refereed)
    Abstract [en]

    With the aim of obtaining nanostructured titania thin films for the tential use in hybrid or dye sensitized solar cells, the amphiphilic block copolymer polystyrene-b-poly(ethylene oxide) is employed as a ructure directing template in combination with solgel chemistry. For sy upscaling, spraying is used as a deposition technique. In situ azing incidence small-angle X-ray scattering (GISAXS) measurements are rformed during spraying and show that most titania structures are ready formed within the solution prior to deposition. However, ructural rearrangement is enabled during the deposition period when all amounts of hydrochloric acid (HCl) are used as a catalytic ditive to the spray solution. This behavior is ascribed to an altering the reaction dynamics and phase separation in the presence of HCl, ich significantly improves the templating effect of the employed block copolymer. With HCl as an additive the final nanoscale rphologies exhibit smaller pore sizes and strongly enhanced order as mpared to thin films sprayed from solutions that do not contain HCl as antified with atomic force microscopy, scanning electron microscopy, d GISAXS.

  • 340.
    Hollertz, Rebecca
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Arwin, Hans
    Faure, Bertrand
    Zhang, Yujia
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Bergström, Lennart
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Dielectric properties of lignin and glucomannan as determined by spectroscopic ellipsometry and Lifshitz estimates of non-retarded Hamaker constants2013In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 20, no 4, p. 1639-1648Article in journal (Refereed)
    Abstract [en]

    We present in this study a quantitative estimate of the dispersive interactions between lignin, hemicellulose and cellulose, which are the dominating components in wood and also extensively used to produce paper and packaging materials. The dielectric properties in the UV-visible region of spin-coated films of pure lignin and glucomannan were determined by spectroscopic ellipsometry. The non-retarded Hamaker constants were estimated from the determined spectral parameters using Lifshitz theory for lignin and glucomannan interacting with cellulose, titania and calcium carbonate in vacuum, water and hexane. The Hamaker constants for the different combinations of cellulose, lignin and glucomannan fall within a relatively narrow range of 35-58 and 8-17 zJ, for the values in vacuum (air) and water, respectively. The estimated Hamaker constants for the interactions of the wood components with TiO2 and CaCO3, common additives in paper, in water range from 3 to 19 zJ, thus being similar in magnitude as the interactions between the wood components themselves. In contrast, the Hamaker constant is essentially zero for glucomannan interacting with calcium carbonate in hexane. The Hamaker constants for lignin, hemicellulose and cellulose determined in this study can provide information regarding the surface interactions important for e.g. adhesion, friction, swelling and wetting in paper processing as well as for the resulting behavior of paper products.

  • 341.
    Hollertz, Rebecca
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Pitois, Claire
    Novel cellulose nanomaterials: Towards usage in electrical insulation2014In: Proceedings of the 2014 IEEE 18th International Conference on Dielectric Liquids, ICDL 2014, 2014, p. 6893152-Conference paper (Refereed)
    Abstract [en]

    Papers, foams and gels from nanofibrillated cellulose (NFC) have emerged as promising materials for various applications. In this study NFC from a Kraft Pulp used in traditional electrical insulation was produced with the aid of a high pressure homogenizer. Papers were manufactured and their mechanical properties as well as their dielectric responses in oil were measured. The disintegration results in a durable, flexible papers with high strength and density while the dielectric response correlate to that of Kraft Paper with similar density. This paper also includes a description on how inorganic nanoparticles was used to modify the properties of the fibres through a topochemical modification. In this latter technique a Layer-by-Layer technology was used where the charges of the fibres are treated with consecutive layers of oppositely charged polyelectrolytes and nanoparticles.

  • 342.
    Holmboe, Michael
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Pharmacy.
    Clay barrier properties studied with in silico techniques2014In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 248Article in journal (Other academic)
  • 343.
    Holmboe, Michael
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics.
    Bourg, Ian C.
    Interlayer diffusion in hydrated smectites - a molecular dynamics study2013In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 245, p. 163-GEOC-Article in journal (Other academic)
  • 344.
    Holmboe, Michael
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Wold, Susanna
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Free Porosity of Compacted Saturated MX-80 Bentonite and Na-montmorillonite as a Function of Dry Density2009Article in journal (Refereed)
  • 345. Hong, Tao
    et al.
    Song, Heli
    Li, Xin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Zhang, Weibing
    Xie, Yongshu
    Syntheses of mono- and diacylated bipyrroles with rich substitution modes and development of a prodigiosin derivative as a fluorescent Zn(II) probe2014In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 4, no 12, p. 6133-6140Article in journal (Refereed)
    Abstract [en]

    The acylation of 2,20-bipyrrole with pentafluorobenzoyl chloride in the presence of AlCl3 afforded six acylated products with rich alpha-, beta-, beta(1)-, alpha,alpha'-, alpha,beta(')-, and alpha,beta(1)'-substitution modes for 1-6, respectively. Then, the alpha,alpha'-diacylated compound 4 was used to synthesize a prodigiosin derivative 9, which provides an alternative method for the syntheses of prodigiosin derivatives. Crystal structures of 1, 4 and 9 show interesting supramolecular dimers formed by multiple hydrogen bonds, O...pi interactions, as well as pi... pi interactions. Interestingly, 9 shows fluorescence turn-on probing behavior towards Zn2+ both in DMF and in DMF-HEPES, with high sensitivity and selectivity. The detection limit for Zn2+ in DMF was calculated to be 1.1 x 10(-8) M.

  • 346. Hosseinpour, S.
    et al.
    Leygraf, Christopher
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Gretic, Z. H.
    Mioc, E. K.
    Curkovic, H. O.
    Bochmann, S.
    Bachmann, J.
    Waegner, V.
    Virtanen, S.
    Peukert, W.
    Self-assembled monolayers as corrosion inhibitors; indoor, marine and biologically relevant exposure2017In: EUROCORR 2017 - The Annual Congress of the European Federation of Corrosion, 20th International Corrosion Congress and Process Safety Congress 2017, Asociace koroznich inzenyru z.s.- AKI - Czech Association of Corrosion Engineers , 2017Conference paper (Refereed)
  • 347.
    Hosseinpour, Saman
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Hedberg, Jonas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Johnson, Magnus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Baldelli, Steven
    Dpt of Chemistry, University of Houston, Texas, US.
    Initial Oxidation of Alkanethiol-Covered Copper Studied by Vibrational Sum Frequency Spectroscopy2011In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 115, no 48, p. 23871-23879Article in journal (Refereed)
    Abstract [en]

    The oxidation of octadecanethiol (ODT, CH3-(CH2)17SH)-covered copper in dry air has been studied by in situ vibrational sum frequency spectroscopy (VSFS), infrared reflection absorption spectroscopy (IRAS), and cathodic reduction (CR). During the first 10 h of exposure, the VSF spectral line shape in the CH stretching region changed

    significantly, with resonances observed as dips being transformed into peaks. This was attributed to a phase change in the nonresonant sum frequency signal due to the formation of a thin layer of copper(I) oxide beneath the ODT. Complementary cathodic reduction and infrared reflection/absorption spectroscopy studies yielded a thickness of the oxide layer of <2 nm after 19 h exposure. An orientation analysis on the adsorbed molecules by VSFS indicated a decreased tilt angle of the terminating methyl groups with respect to the surface normal during the formation of the oxide layer.

  • 348.
    Hosseinpour, Saman
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Johnson, C. Magnus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Alkanethiols as inhibitors for the atmospheric corrosion of copper induced by formic acid: Effect of chain length2013In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 160, no 6, p. C270-C276Article in journal (Refereed)
    Abstract [en]

    Self assembled monolayers (SAMs) of n-alkanethiols of different chain length (4, 6, 8, 12, and 18 carbons in the chain) have been explored as corrosion inhibitors for copper exposed to humidified air containing formic acid, an environment used to mimic accelerated indoor atmospheric corrosion. Near-surface sensitive in-situ infrared reflection/absorption spectroscopy combined with interface sensitive vibrational sum frequency spectroscopy revealed unique molecular information on the role of each SAM during ongoing corrosion. All SAMs protect copper against corrosion, and this ability increases continuously with chain length. Their structural order is high prior to exposure, but an increased disorder is observed as a result of the corrosion process. The protection ability of the SAMs is attributed to a selective hindrance of the corrosion stimulators water, oxygen gas, and formic acid to reach the copper-SAM interface through each SAM, which results in different corrosion mechanisms on SAM protected copper and unprotected copper. This significantly retards the formation of the corrosion products copper hydroxide and copper formate, and results in essentially no formation of cuprite.

  • 349. Hou, Yi
    et al.
    Hu, Songqing
    Lindström, Mikael E.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Feasibility of monomer aromatic substances as calibration standards for lignin quantitative analyses in Pyrolysis-GCMS2013In: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 101, p. 232-237Article in journal (Refereed)
    Abstract [en]

    In this article, the feasibilities of five different monomer aromatic substances as calibration standards by analytical pyrolysis with gas chromatographic separation and mass selective detection (Py-GC/MS) were applied for the quantification of lignin in paper and pulp. The stabilities of these substances in the pyrolysis process were evaluated and the curves of peak response area to mass also were obtained. The results showed that the substances with exact same substitutions on the benzene ring as lignin units had good stabilities in the pyrolysis process with good lineabilities of peak response area to the mass curves, which implicated these substances can be applied as calibration standards in the liginin quick quantitative analyse without tedious pretreatments and structure changes.

  • 350. Houde, Magali
    et al.
    Pacepavicius, Grazina
    Darling, Colin
    Fair, Patricia A
    Alaee, Mehran
    Bossart, Gregory D
    Solomon, Keith R
    Letcher, Robert J
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Marsh, Göran
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Muir, Derek C G
    POLYBROMINATED DIPHENYL ETHERS AND THEIR HYDROXYLATED ANALOGS IN PLASMA OF BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS) FROM THE UNITED STATES EAST COAST.2009In: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 28, no 10, p. 2061-2068Article in journal (Refereed)
    Abstract [en]

    Polybrominated diphenyl ethers (PBDEs) and hydroxylated-PBDEs (OH-PBDE) were determined in plasma of free-ranging bottlenose dolphins (Tursiops truncatus) from Charleston (CHS), South Carolina, and the Indian River Lagoon (IRL), Florida, US. Significantly lower sum (Sigma) of PBDE concentrations (sum of 12 congeners) were found in animals from the IRL [arithmetic mean: 5.454.63 ng/g wet weight (ww)] compared to CHS (3040 ng/g ww). BDE-47 was the predominant PBDE in dolphins from the IRL (50% of the SigmaPBDEs) and CHS (58%). SigmaPBDE concentrations in plasma of dolphins were negatively correlated with age at both locations. Fifteen and sixteen individual OH-PBDE congeners could be quantified in plasma of dolphins from IRL and CHS, respectively. Similar to SigmaPBDE, mean SigmaOH-PBDE concentrations were significantly higher in plasma of dolphins at CHS (1150708 pg/g ww) compared to IRL (624393 pg/g ww). The predominant congener at both locations was 6-OH-PBDE 47 (IRL: 384319 pg/g ww; CHS: 541344 pg/g ww) representing 61.5% of total SigmaOH-PBDE at IRL and 47.0% at CHS. Concentrations of SigmaOH-PBDEs were weakly negatively correlated with age in dolphins from both locations (P<0.05; IRL, R2=0.048; CHS, R2=0.021). In addition to the OH-PBDE congeners identified with technical standards, eight and four unidentified OH-PBDEs were detected and quantified respectively in animals from CHS (sum of unidentified OH-PBDEs=1.350.90 pg/g ww) and IRL (0.730.40 pg/g ww). Our results suggest that, unlike OH-PCBs, OH-PBDEs in bottlenose dolphins are minor products in plasma relative to SigmaPBDEs and a significant proportion may be a consequence of the dietary uptake of naturally produced methoxylated- and OH-PBDEs.

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