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  • 301.
    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.))
  • 302.
    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.

  • 303.
    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.

  • 304.
    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.

  • 305.
    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.

  • 306.
    Heinze, Thomas
    et al.
    Friedrich Schiller University of Jena.
    et al., et al.
    Friedrich Schiller University of Jena.
    Cellulose Carbonates: A Platform for Promising Biopolymer Derivatives with Multifunctional Capabilities2016Conference paper (Other academic)
    Abstract [en]

    In addition to cellulose tosylates (Heinze et al 2016), cellulose carbonates represent a new type of platform compounds that open new possibilities for the design of advanced materials based on the most important renewable resource cellulose. In addition, the synthesis concept can be used for polysaccharides in general that could be proofed for starch and dextran carbonates. In the presentation, the efficient preparation of well-soluble cellulose carbonates is discussed based on own research program about organo-soluble and reactive polysaccharide derivatives. Homogeneous procedures are most efficient applying typical cellulose solvents including N,N-dimethylacetamide (DMAc)/LiCl and ionic liquids (IL) in combination with organic solvents like pyridine. Even products with complete functionalization of all hydroxyl groups are available (degree of substitution, DS 3). The cellulose carbonates are commercially available from a start-up company and are well suitable for homogeneous conversion with nucleophilic compounds in particular with amines. They are easily soluble in organic solvents; thus, the time-consuming and tricky dissolution of cellulose in complex solvents can be omitted. The synthesis and aminolysis of cellulose carbonates with low, intermediate, and high DS and the evaluation of this chemistry with respect to specific challenges will be exemplarily discussed. Functional cellulose carbamates, obtained from cellulose phenyl carbonate by aminolysis, show the potential use of this class of celluloses. Immunoassays, zwitterionic polymers, products for laundry applications are included as representative examples regarding properties and application of the new cellulose-based products (Elschner and Heinze 2015) 

  • 307.
    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.

    The full text will be freely available from 2018-12-21 09:05
  • 308.
    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.

  • 309.
    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.

  • 310.
    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.

  • 311.
    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.

  • 312.
    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.

  • 313. Heydari, G.
    et al.
    Tyrode, E.
    Visnevskij, C.
    Makuska, R.
    Claesson, Per M.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Material och ytteknik. Department of Chemistry Surface and Corrosion Science, KTH Royal Institute of Technology.
    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.

  • 314.
    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.))
  • 315. Hjalmarsson, N.
    et al.
    Atkin, R.
    Rutland, Mark W.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Life Science. Department of Surface and Corrosion Science, School of Chemical Science and Engineering, KTH Royal Institute of Technology.
    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).

  • 316. Hjalmarsson, N.
    et al.
    Wallinder, D.
    Glavatskih, S.
    Atkin, R.
    Aastrup, T.
    Rutland, Mark W.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Life Science. Department of Surface and Corrosion Science, School of Chemical Science and Engineering, KTH Royal Institute of Technology.
    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.

  • 317.
    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.

  • 318.
    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.

  • 319.
    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)
  • 320.
    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)
  • 321.
    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)
  • 322. 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.

  • 323. 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)
  • 324.
    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.

  • 325.
    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.

  • 326. 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.

  • 327. 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.

  • 328.
    Huang, Hui
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Dobryden, Illia
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Thorén, Per Anders
    KTH, School of Engineering Sciences (SCI), Applied Physics, Nanostructure Physics.
    Ejenstam, Lina
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. SP Technical Research Institute of Sweden.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Fielden, Matthew
    KTH, School of Engineering Sciences (SCI), Applied Physics, Nanostructure Physics.
    Haviland, David
    KTH, School of Engineering Sciences (SCI), Applied Physics, Nanostructure Physics.
    Claesson, Per Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. SP Technical Research Institute of Sweden.
    Local surface mechanical properties of PDMS-silica nanocomposite probed with Intermodulation AFM2017In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 150, p. 111-119Article in journal (Refereed)
    Abstract [en]

    The mechanical properties of polymeric nanocomposites are strongly affected by the nature of the interphase between filler and matrix, which can be controlled by means of surface chemistry. In this report, we utilize intermodulation atomic force microscopy (ImAFM) to probe local mechanical response with nanometer-scale resolution of poly(dimethylsiloxane) (PDMS) coatings with and without 20 wt% of hydrophobic silica nanoparticles. The data evaluation is carried out without inferring any contact mechanics model, and is thus model-independent. ImAFM imaging reveals a small but readily measurable inhomogeneous mechanical response of the pure PDMS surface layer. The analysis of energy dissipation measured with ImAFM showed a lowering of the viscous response due to the presence of the hydrophobic silica nanoparticles in the polymer matrix. An enhanced elastic response was also evident from the in-phase stiffness of the matrix, which was found to increase by a factor of 1.5 in presence of the nanoparticles. Analysis of dissipation energy and stiffness in the immediate vicinity of the nanoparticles provides an estimate of the interphase thickness. Because the local stiffness varies significantly near the nanoparticle, AFM height images contain artifacts that must be corrected in order to reveal the true surface topography. Without such a correction the AFM height images erroneously show that the stiff particles protrude from the surface, whereas corrected images show that they are actually embedded in the matrix and likely covered with a thin layer of polymer.

  • 329. Huo, Jinxing
    et al.
    Rojas, Ramiro
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Bohlin, Jan
    Hilborn, Jöns
    Gamstedt, E. Kristofer
    Parametric elastic analysis of coupled helical coils for tubular implant applications: experimental characterization and numerical analysis.2014In: Journal of The Mechanical Behavior of Biomedical Materials, ISSN 1751-6161, E-ISSN 1878-0180, Vol. 29, no SI, p. 462-469Article in journal (Refereed)
    Abstract [en]

    Coupled helical coils show promising mechanical behavior to be used as tubular organ constructs, e.g., in trachea or urethra. They are potentially easy to manufacture by filament winding of biocompatible and resorbable polymers, and could be tailored for suitable mechanical properties. In this study, coupled helical coils were manufactured by filament winding of melt-extruded polycaprolactone, which was reported to demonstrate desired in vivo degradation speed matching tissue regeneration rate. The tensile and bending stiffness was characterized for a set of couple helical coils with different geometric designs, with right-handed and left-handed polymer helices fused together in joints where the filaments cross. The Young's modulus of unidirectional polycaprolactone filaments was characterized, and used as input together with the structural parameters of the coupled coils in finite element simulations of tensile loading and three-point bending of the coils. A favorable comparison of the numerical and experimental results was found, which paves way for use of the proposed numerical approach in stiffness design under reversible elastic conditions of filament wound tubular constructs.

  • 330.
    Huotari, Joni
    et al.
    Microelectronics and Material Physics Laboratories, University of Oulu, Finland.
    Lappalainen, Jyrki
    Microelectronics and Material Physics Laboratories, University of Oulu, Finland.
    Puustinen, Jarkko
    Microelectronics and Material Physics Laboratories, University of Oulu.
    Baur, Tobias
    Department of Mechatronics, Saarland University, Germany.
    Alepee, Christine
    SGX Sensortech SA, Switzerland.
    Haapalainen, Tomi
    Microelectronics and Material Physics Laboratories, University of Oulu, Finland.
    Komulainen, Samuli
    Microelectronics and Material Physics Laboratories, University of Oulu, Finland.
    Pylvänäinen, Juho
    Microelectronics and Material Physics Laboratories, University of Oulu, Finland.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, Faculty of Science & Engineering. Microelectronics and Material Physics Laboratories, University of Oulu, Finland.
    Pulsed laser deposition of metal oxide nanoparticles, agglomerates, and nanotrees for chemical sensors2015In: Procedia Engineering, ISSN 1877-7058, E-ISSN 1877-7058, Vol. 120, p. 1158-1161Article in journal (Refereed)
    Abstract [en]

    Pulsed laser deposition (PLD) was used to prepare WO3, ZnO-modified SnO2, and V2O5 nanostructures as gas sensing materials on top of commercial SGX Sensortech MEMS microheater platforms. The layers were formed of different types of nanostructures including nanoparticles, agglomerates, and nanotrees with fractal-like growth. Clear dependency between the deposition parameters, structural morphology, and gas sensing performance was found. The sensing materials were found to be sensitive to different types of gaseous species, so that WO3 and SnO2 had very good response up to 600% to 50 ppm NO, and V2O5 up to -35% to 20 ppm NH3, respectively.

  • 331.
    Hussain, Tanveer
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Chakraborty, Sudip
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Kang, T. W.
    Johansson, Borje
    Ahuja, Rajeev
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    BC3 Sheet Functionalized with Lithium-Rich Species Emerging as a Reversible Hydrogen Storage Material2015In: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641, Vol. 16, no 3, p. 634-639Article in journal (Refereed)
    Abstract [en]

    The decoration of a BC3 monolayer with the polylithiated molecules CLi4 and OLi2 has been extensively investigated to study the hydrogen-storage efficiency of the materials by first principles electronic structure calculations. The binding energies of both lithiated species with the BC3 substrate are much higher than their respective cohesive energies, which confirms the stability of the doped systems. A significant positive charge on the Li atom in each of the dopants facilitates the adsorption of multiple H-2 molecules under the influence of electrostatic and van der Waals interactions. We observe a high H-2-storage capacity of 11.88 and 8.70 wt% for the BC3-CLi4 and BC3-OLi2 systems, respectively, making them promising candidates as efficient energy-storage systems.

  • 332. Iavicoli, P.
    et al.
    Xu, H.
    Feldborg, L. N.
    Linares, Mathieu
    Linköping University, Sweden .
    Paradinas, M.
    Stafström, S.
    Ocal, C.
    Nieto-Ortega, B.
    Casado, J.
    Navarrete, J. T. L.
    Lazzaroni, R.
    De Feyter, S.
    Amabilino, D. B.
    Tuning the supramolecular chirality of one-and two-dimensional aggregates with the number of stereogenic centers in the component porphyrins2010In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 132, no 27, p. 9350-9362Article in journal (Refereed)
    Abstract [en]

    A synthetic strategy was developed for the preparation of porphyrins containing between one and four stereogenic centers, such that their molecular weights vary only as a result of methyl groups which give the chiral forms. The low-dimensional nanoscale aggregates of these compounds Reveal the profound effects of this varying molecular chirality on their supramolecular structure and optical activity. The number of stereogenic centers influences significantly the self-assembly and chiral structure of the aggregates of porphyrin molecules described here. A scanning tunneling microscopy study of monolayers on graphite shows that the degree of structural chirality with respect to the surface increases almost linearly with the number of stereogenic centers, and only one handedness is formed in the monolayers, whereas the achiral compound forms a mixture of mirror-image domains at the surface. In solution, four hydrogen bonds induce the formation of an H-aggregate, and circular dichroism measurements and theoretical studies indicate that the compounds self-assemble into helical structures. Both the chirality and stability of the aggregates depend critically on the number of stereocenters. The chiral porphyrin derivatives gelate methylcyclohexane at concentrations dependent on the number and position of chiral groups at the periphery of the aromatic core, reflecting the different aggregation forces of the molecules in solution. Increasing the number of stereogenic centers requires more material to immobilize the solvent, in all likelihood because of the greater solubility of the porphyrins. The vibrational circular dichroism spectra of the gels show that all compounds have a chiral environment around the amide bonds, confirming the helical model proposed by calculations. The morphologies of the xerogels (studied by scanning electron microscopy and scanning force microscopy) are similar, although more fibrous features are present in the molecules with fewer stereogenic centers. Importantly, the presence of only one stereogenic center, bearing a methyl group as the desymmetrizing ligand, in a molecule of considerable molecular weight is enough to induce singlehanded chirality in both the one-and two-dimensional supramolecular self-assembled structures.

  • 333.
    Idström, Alexander
    et al.
    Swerea IVF.
    Gentil, Luigi
    Lund University.
    Gubitosi, Marta
    Lund University.
    Olsson, Carina
    Swerea IVF.
    Stenqvist, Björn
    Lund University.
    Lund, Mikael
    Lund University.
    Olsson, Ulf
    Lund University.
    Köhnke, Tobias
    Swerea IVF.
    Bergquist, Karl-Erik
    Lund University.
    Dissolution of cellulose in tetrabutylammonium acetate/dimethyl sulfoxide2016In: The 7th workshop on cellulose, regenerated cellulose and cellulose derivatives, 2016Conference paper (Other academic)
    Abstract [en]

    The dissolution of cellulose in tetrabutylammonium acetate (TBAAc)/dimethyl sulfoxide (DMSO) was studied combining experimental and simulation techniques. It was found that the dissolution limit at 40 °C corresponded to a molar ratio close to one acetate per cellulose anhydroglucose units. MD simulations suggested that the acetate ions bind to cellulose by dual hydrogen bonds. This effectively turns cellulose into a polyelectrolyte, attracting the bulky tetrabutylammonium (TBA+) counter ions, which prevent close contact between chains in the dissolved state. This hypothesis was tested by 1H- and 13C-NMR spectroscopy, which confirmed that acetate forms hydrogen bonds to cellulose, and by diffusion NMR spectroscopy, which demonstrated a strong dynamic correlation between bound acetate and tetrabutylammonium in near-quantitative agreement with simulation. The present results suggest that offering hydrogen bonding to the acetate ions is the main driving force for dissolving cellulose and that the TBA+ counter ions form a diffuse layer around the acetate-decorated cellulose chains.

  • 334.
    Illergård, Josefin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Ek, Monica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Contact-active antibacterial polyelectrolyte multilayers: The influence of substrate2013In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 245, p. 515-PMSE-Article in journal (Other academic)
  • 335.
    Isaksson, Sara
    KTH, School of Chemical Science and Engineering (CHE).
    Simulation of Metal and Metal Oxide Nanoparticle Sedimentation in Solution Using a Computational Model2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Nanoparticles are used in many different applications because of their small size and unique properties. The usage is increasing rapidly, which will increase the nanoparticle exposure to the environment. Up till now, environmental behavior and ecotoxicology of nanoparticles have only been studied to a certain extent and because of the increasing usage, research should focus more on nanoparticle behavior and ecotoxicology. An effective way of studying nanoparticles in aqueous environments is to use mathematical models. In this study, the In vitro Sedimentation, Diffusion, and Dosimetry (ISDD) model was investigated and applied to copper, manganese, and zinc oxide nanoparticles to determine their sedimentation velocity in 1 mM NaClO4(aq).

     

    The results show that the simulated sedimentation of nanoparticles in solution, i.e. the output from the ISDD model, can vary a lot depending on some of the input parameters in the model. The fact that some of these parameters have to be estimated increases the uncertainty of the ISDD model, although it is possible to yield results in great agreement with experimentally determined sedimentation velocities for the studied systems. The simulation results could always be explained by the theory behind it, which increases the reliability of the ISDD model.

     

    The possibility of measuring the effective density of nanoparticle agglomerates using the volumetric centrifugation method was also investigated. This method makes it possible to avoid estimating the fractal dimension, an input parameter with great uncertainty in the ISDD model. The results look promising, although further investigation is needed. 

     

    The ISDD model seems to be a promising model for future simulation work. The model should be investigated further in order to minimize the uncertainties due to estimations. The possibility to predict nanoparticle sedimentation using a mathematical model will save a lot of time and money, and it can be a helpful tool in the extensive work of identifying the behavior of nanoparticles in aqueous environments.   

  • 336.
    Israel, Liron L.
    et al.
    Bar Ilan Univ, Dept Chem, IL-5290002 Ramat Gan, Israel.;Bar Ilan Univ, Inst Nanotechnol & Adv Mat, IL-5290002 Ramat Gan, Israel..
    Karimi, Farhad
    Bencar AB, Uppsala, Sweden..
    Bianchessi, Silvia
    Fdn Filarete, I-20139 Milan, Italy..
    Scanziani, Eugenio
    Fdn Filarete, I-20139 Milan, Italy..
    Passoni, Lorena
    Fdn Filarete, I-20139 Milan, Italy..
    Matteoli, Michela
    Univ Milan, I-20129 Milan, Italy.;Univ Milan, Humanitas Clin & Res Ctr, Dipartimento Biotecnol Med & Med Traslaz, I-20129 Milan, Italy..
    Långström, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC. Bencar AB, Uppsala, Sweden..
    Lellouche, Jean-Paul
    Bar Ilan Univ, Dept Chem, IL-5290002 Ramat Gan, Israel.;Bar Ilan Univ, Inst Nanotechnol & Adv Mat, IL-5290002 Ramat Gan, Israel..
    Surface metal cation doping of maghemite nanoparticles: modulation of MRI relaxivity features and chelator-free Ga-68-radiolabelling for dual MRI-PET imaging2015In: MATERIALS RESEARCH EXPRESS, ISSN 2053-1591, Vol. 2, no 9, article id 095009Article in journal (Refereed)
    Abstract [en]

    Magnetically responsive maghemite (gamma-Fe2O3) nanoparticles (NPs) are the subject of current interest due to their potential use as contrast agents for in vivo magnetic resonance imaging (MRI). In addition, PET (positron emission tomography) is another non-invasive molecular imaging modality based on nuclear medicine and short-lived positron radionuclides incorporated in various bioprobes. In previous work (Haviv et al 2010 J. Am. Chem. Soc. 132 12519-12521), Massart magnetite (Fe3O4) oxidation using ceric ammonium nitrate (CAN) was explored. The resulting hydrophilic maghemite (gamma-Fe2O3) NPs formed a stable aqueous colloid/ferrofluid that disclosed a low level of NP surface doping by Ce3/4+ atoms/cations. In this work, magnetically responsive gallium(III) or various other lanthanide(III) cation-doped maghemite NPs were prepared in different ways which influenced their r(2)* MRI relaxivities, which were usually strengthened vs those of known FDA approved ferrofluids. In addition, this resulting NP surface chemistry enabled their direct labeling with PET-enabled Ga-68(III) cations (scheme 1) without using any attached chelating organic species/polymer, providing PET-enabled radioactive magnetic NPs towards a novel dual PET/MRI imaging nanoscale agent.

  • 337. Ivaniuk, K.
    et al.
    Cherpak, V.
    Stakhira, P.
    Baryshnikov, Gleb
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Bohdan Khmelnytsky National University, Ukraine.
    Minaev, Boris
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Bohdan Khmelnytsky National University, Ukraine.
    Hotra, Z.
    Turyk, P.
    Zhydachevskii, Y.
    Volyniuk, D.
    Aksimentyeva, O.
    Penyukh, B.
    Lazauskas, A.
    Tamulevičius, S.
    Grazulevicius, J. V.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Siberian Federal University, Russian Federation.
    BaZrO3 perovskite nanoparticles as emissive material for organic/inorganic hybrid light-emitting diodes2017In: Dyes and pigments, ISSN 0143-7208, E-ISSN 1873-3743, Vol. 145, p. 399-403Article in journal (Refereed)
    Abstract [en]

    In the present work we have demonstrated double-channel emission from organic exciplexes coupled to inorganic nanoparticles. The process is demonstrated by yellow-green emission in light-emitting diodes based on organic exciplexes hybridized with perovskite-type dispersed BaZrO3 nanoparticles. Such double-channel emission provides a broadening of the electroluminescence spectrum and a resultant yellow-green emission color of the device. We have realized an energy transfer from the exciplexes arranged by the interface between two organic layers and the spherical-shaped BaZrO3 nanoparticles randomly deposited on the organic interface constructed of the tris(4-carbazoyl-9-ylphenyl)amine and 4,7-diphenyl-1,10-phenanthroline molecules. The fabricated device exhibits a current efficiency value of 3.88 C d/A, maximum brightness of 3465 cd/m2 (at 15 V), and external quantum efficiency of about 1.26%. In order to estimate the efficiency of the energy transfer from the exciplex to the BaZrO3 nanoparticles we have applied the Förster model for the dipole-dipole energy transfer accounting for the mutual overlap of the exciplex emission spectrum and the absorption spectrum of the BaZrO3 nanoparticles.

  • 338.
    Jacob, Rebecca
    KTH, School of Chemical Science and Engineering (CHE).
    Lipid bilayers and their interactions with the antimicrobial peptide LL37: a TIR Raman study2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As a direct consequence of the misuse of antibiotics since its first discovery, bacteria have developed extensive resistance mechanisms making them once again potential lethal threats. This eventuality has triggered a vast research effort from scientists worldwide to find solutions to mitigate antimicrobial resistance. One such option is the identification of new potential antimicrobial agents, like for example antimicrobial peptides (AMPs). Various methods have been applied to evaluate the properties and determine the complex mechanism of AMPs. However, the details of the mechanism remain unknown and hence the work in this project seeks to examine the suitability of using TIR Raman, a vibrational spectroscopy technique which is sufficiently surface sensitive to study the interaction of AMPs in contact with lipid bilayers, which are just a few nanometres thick.

    In order to evaluate the information that could be extracted from TIR Raman, measurement of solid supported lipid bilayers in the absence of peptides were first carried out. In particular, the lipid DMPC with a phase transition close to room temperature, was measured at various temperatures to determine spectral changes associated with the transition. For the peptide-membrane interactions, the AMP LL37 was put into contact with solid supported lipid bilayers modelling the cell membranes of bacteria (DOPE, DOPG) or humans (DOPC) respectively. The data clearly indicates that the membrane composition, and specifically the lipid head group charge, play an important role in the peptide-membrane interactions. In the bilayers mimicking bacteria cell membranes, the peptide either absorbed onto or inserted into the bilayer. In contrast, for the bilayer modelling a human cell membrane, no significant variations were detected, indicating no interaction with LL37. The findings presented in this work generally coincide with similar research of LL37 using other techniques. At hand of the herein presented data, TIR Raman has proven suitable and effective in detecting effects of antimicrobial peptides in contact with model lipid bilayers, and hence can be recommended for further studies.

  • 339.
    Jafarzadeh, Shadi
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Goidanich, Sara
    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.
    A comparison between corrosion-induced metal release from copper-based alloys at field conditions and at laboratory simulated bulk conditions using the OECD T/D test2008In: Proc. 17th International Corrosion Congress: Oct 6-10, Las Vegas, 2008Conference paper (Refereed)
  • 340.
    Jafarzadeh, Shadi
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Johansson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Sundell, P. -E
    Claudino, Mauro
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Pan, Jinshan
    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.
    UV-curable acrylate-based nanocomposites: Effect of polyaniline additives on the curing performance2013In: Polymers for Advanced Technologies, ISSN 1042-7147, E-ISSN 1099-1581, Vol. 24, no 7, p. 668-678Article in journal (Refereed)
    Abstract [en]

    Composites of nanostructured polyaniline (PANI) conducting polymer in a polyester acrylate (PEA) formulation were made to provide conductive organic coatings. The effect of the presence and amount of PANI on the photocuring performance of the ultraviolet (UV)-curable acrylate system has been investigated employing real-time Fourier transform infrared spectroscopy as the main technique. Longer initial retardation of the radical polymerization and lower rates of cross-linking reactions were observed for dispersions containing PANI of higher than 3wt.%. The PEA/PANI samples were more affected than the neat PEA resin by the changes in UV light intensity and oxygen accessibility during UV curing. Samples with higher PANI content, of up to 10wt.%, were tested and could be partially cured even at UV light intensities as low as 2mW cm-2 when the oxygen replenishment into the system was inhibited. Thermal analysis revealed that the presence of PANI did not induce any significant change in Tg of the cured system, meaning that early decrease in mobility and vitrification is not the reason for lower ultimate conversion of the dispersions with higher PANI content compared with the neat PEA resin. Curing under strong UV lamps, of 1.5W cm-2 intensity, made it possible to reach high degrees of conversion on films with similar mechanical properties independent of the PANI content.

  • 341. Jakobsson, K.
    et al.
    Fång, Johan
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Athanasiadou, Maria
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Rignell-Hydbom, A.
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Polybrominated diphenyl ethers in maternal serum, umbilical cord serum, colostrum and mature breast milk: Insights from a pilot study and the literature2012In: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 47, p. 121-130Article in journal (Refereed)
    Abstract [en]

    Human serum and mother's milk are frequently used to assess exposure to polybrominated diphenyl ethers (PBDEs), including transplacental transfer to the foetus. However, little is known about the kinetics of PBDEs, especially the highly brominated BDE congeners.

    In this pilot study, maternal serum samples were collected from 10 women at delivery and five to six weeks post partum. Umbilical serum was also obtained. Milk was donated two to five days, and five to six weeks after delivery. The amount of PBDEs in these samples was determined using liquid–liquid extraction and GC/MS.

    Low, moderately and highly brominated diphenyl ethers were present in umbilical cord serum, indicating placental transfer. The lipid-adjusted levels of BDE-47, BDE-207 and BDE-209 were similar in maternal and umbilical cord serum, whereas the cord serum levels for the penta- to octa-BDEs quantified were lower than in maternal serum.

    Marked changes were seen in the congener pattern in breast milk during the first month of lactation, whereas maternal serum levels did not change significantly. The general pattern was an enrichment of low to moderately brominated congeners (i.e. from BDE-17 to BDE-154, with the exception of BDE-28) in colostrum compared with maternal serum. In contrast, more highly brominated congeners were found at similar, or lower levels in colostrum than in maternal serum. After the transition from colostrum to mature milk, the levels of BDE-153 and BDE-209 were substantially reduced, and BDE‐209 was below the limit of detection in 6 out of 9 samples.

    A literature review on the design and reporting of studies on the transfer of PBDEs from mother to infant revealed a lack of transparency in many cases. The use of the recently published STROBE-ME guidelines is therefore recommended.

  • 342.
    Jakobsson, Liv
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Evaluating the Interactions of Chitosan with Mucus for the Development of a Non-Hormonal Contraceptive2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    There is a huge need for non-hormonal contraceptives today, as many women suffer from hormone related side effects. Cervical mucus allows spermatozoa penetration only around ovulation, when the mucins in it form loose networks. Our aim is to develop a new, safe, and easily administered non-hormonal contraceptive. The strategy is to utilize the mucoadhesive properties of chitosan biopolymers to crosslink mucins and thus strengthen the cervical mucus barrier. To achieve this, the interactions of chitosan with mucus must be evaluated. The objectives of this study are as follows; a) quantification of the complexation between chitosan with different physicochemical properties and the model mucin pig gastric mucin (PGM), b) an optimization study of different pH and dissolution buffers with different osmolalities, and c) observation of chitosan penetration into human cervical mucus. The complexation was quantified indirectly by fluorometric quantitation of chitosan concentration before and after complexation. The optimization study was performed by complexation at pH 4.5, 5.5, 6.5, and 7.5, and with dissolution buffers water (~0 mOsm/kg), phosphate buffered saline (~100 mOsm/kg), and a custom produced buffer (~300 mOsm/kg). Accumulation and distribution of chitosan in human cervical mucus was studied by allowing fluorescently labelled chitosan to diffuse into capillaries filled with human cervical mucus, then visualized by fluorescence microscopy. This study shows that Chitosan Oligomer (CO) complexed the most with PGM in relation to further chitosans investigated. The complexation of CO with PGM was not pH dependent. The highest complexation of CO with PGM, as well as the highest accumulation of CO in human cervical mucus was achieved when CO was dissolved in the buffer with the highest osmolality (~300 mOsm/kg). Therefore, CO dissolved in a buffer of high osmolality is the most interesting chitosan solution for further investigation towards the development of a non-hormonal contraceptive.

  • 343. Jana, Avijit
    et al.
    Nguyen, Kim Truc
    Li, Xin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Zhu, Pengcheng
    Tan, Nguan Soon
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Zhao, Yanli
    Perylene-Derived Single-Component Organic Nanoparticles with Tunable Emission: Efficient Anticancer Drug Carriers with Real-Time Monitoring of Drug Release2014In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 8, no 6, p. 5939-5952Article in journal (Refereed)
    Abstract [en]

    An organic nanoparticle-based drug delivery system with high drug loading efficacy (similar to 79 wt %) was developed using a perylene-derived photoremovable protecting group, namely, perylene-3,4,9,10-tetrayltetramethanol (Pe(OH)(4)). The anticancer drug chlorambucil was protected by coupling with Pe(OH)(4) to form photocaged nanoparticles (Pe(OH)(4)). The photorelease mechanism of chlorambucil from the Pe(Cbl)(4) conjugate was investigated experimentally by high-resolution mass spectrometry and theoretically by density functional theory calculations. The Pe(Cbl)(4) nanoparticles perform four important roles: (i) a nanocarrier for drug delivery, (ii) a phototrigger for drug release, (iii) a fluorescent chromophore for cell imaging, and (iv) a photoswitchable fluorophore for real-time monitoring of drug release. Tunable emission of the perylene-derived nanoparticles was demonstrated by comparing the emission properties of the Pe(OH)(4) and Pe(Cbl)(4) nanoparticles with perylene-3-ylmethanol. These nanoparticles were subsequently employed in cell imaging for investigating their intracellular localization. Furthermore, the in vivo toxicity of the Pe(OH)(4) nanoparticles was investigated using the mouse model. Histological tissue analysis of five major organs, i.e., heart, kidney, spleen, liver, and lung, indicates that the nanoparticles did not show any obvious damage to these major organs under the experimental conditions. The current research presents a successful example of integrating multiple functions into single-component organic nanoparticles for drug delivery.

  • 344.
    Jansson, J
    et al.
    Chalmers University of Technology.
    Palmqvist, A E C
    Chalmers University of Technology.
    Fridell, E
    Chalmers University of Technology.
    Skoglundh, M
    Chalmers University of Technology.
    Österlund, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Thormahlen, P
    Chalmers University of Technology.
    Langer, V
    Chalmers University of Technology.
    On the catalytic activity of Co3O4 in low-temperature CO oxidation2002In: Journal of Catalysis, ISSN 0021-9517, E-ISSN 1090-2694, Vol. 211, no 2, p. 387-397Article in journal (Refereed)
    Abstract [en]

    Oxidation of CO over Co3O4 at ambient temperature was studied with flow reactor experiments, and in-situ spectroscopic and structural methods. The catalyst deactivates during the reaction. The rate of deactivation increased with increasing CO or CO2 gas-phase concentration but decreased with increased 02 concentration or increased temperature. Regeneration of the catalyst in 10% O-2/Ar was more efficient than regeneration in Ar alone. The presence of carbonates and surface carbon on the deactivated catalyst was concluded from TPO experiments. None of these species could, however, be correlated with the deactivation of the catalyst. In-situ FTIR showed the presence of surface carbonates, carbonyl, and oxygen species. The change in structure and oxidation state of the catalyst was studied by in-situ XRD, in-situ XANES, XPS, and flow reactor experiments. One possible explanation for the deactivation of the catalyst is a surface reconstruction hindering the redox cycle of the reaction. (C) 2002 Elsevier Science (USA).

  • 345.
    Jantunen, Liisa
    et al.
    Environment Canada, Canada.
    Wong, Fiona
    Stockholm University.
    Gawor, Anya
    Environment Canada.
    Kylin, Henrik
    Linköpings universitet, Tema Miljöförändring.
    Helm, Paul
    Ontario Ministry of the Environment, Canada.
    Stern, Gary
    University of Manitoba, Canada.
    Strachan, William
    Environment Canada, Canada.
    Burniston, Deborah
    Environment Canada, Canada.
    Bidleman, Terry
    Umeå University.
    20 Years of Air-Water Gas Exchange Observations for Pesticides in the Western Arctic Ocean2015In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, no 23, p. 13844-13852Article in journal (Refereed)
    Abstract [en]

    The Arctic has been contaminated by legacy organochlorine pesticides (OCPs) and currently used pesticides (CUPs) through atmospheric transport and oceanic currents. Here we report the time trends and air−water exchange of OCPs and CUPs from research expeditions conducted between 1993 and 2013. Compounds determined in both air and water were trans- and cis-chlordanes (TC, CC), trans- and cis-nonachlors (TN, CN), heptachlor exo-epoxide (HEPX), dieldrin (DIEL), chlorobornanes (ΣCHBs and toxaphene), dacthal (DAC), endosulfans and metabolite endosulfan sulfate (ENDO-I, ENDO-II, and ENDO SUL), chlorothalonil (CHT), chlorpyrifos (CPF), and trifluralin (TFN). Pentachloronitrobenzene (PCNB and quintozene) and its soil metabolite pentachlorothianisole (PCTA) were also found in air. Concentrations of most OCPs declined in surface water, whereas some CUPs increased (ENDO-I, CHT, and TFN) or showed no significant change (CPF and DAC), and most compounds declined in air. Chlordane compound fractions TC/(TC + CC) and TC/(TC + CC + TN) decreased in water and air, while CC/(TC + CC + TN) increased. TN/(TC + CC + TN) also increased in air and slightly, but not significantly, in water. These changes suggest selective removal of more labile TC and/or a shift in chlordane sources. Water−air fugacity ratios indicated net volatilization (FR > 1.0) or near equilibrium (FR not significantly different from 1.0) for most OCPs but net deposition (FR < 1.0) for ΣCHBs. Net deposition was shown for ENDO-I on all expeditions, while the net exchange direction of other CUPs varied. Understanding the processes and current state of air−surface exchange helps to interpret environmental exposure and evaluate the effectiveness of international protocols and provides insights for the environmental fate of new and emerging chemicals.

  • 346.
    Jenevieve Linell, Yao
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Nano-Graphene Oxide Surface-Functionalized Poly(e-caprolactone) Scaffolds with Drug Delivery Capability2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Grafenoxid (GO) ar en lovande kandidat som nano-tillsats i medicinska byggnadsstallningar for benregenerering. GO kan forbattra den biologiska kompatibiliteten och osteogena prestandan hos polymerbaserade byggstallningar, och ocksa vasentligt bidra till forbattringen av materialets mekaniska egenskaper. I detta arbete ympades nano-grafenoxid (nGO) kovalent pa ytan av poly (e-kaprolakton) (PCL) genom att fdrst modifiera polymerytan via aminolys. Med anvandning av 1,6-hexandiamin / isopropanol infordes fria amingrupper framgangsrikt pa PCL-ytan for efterfoljande immobilisering av nGO. En optimerad ympningsprocess utvecklades via en losningsmedelsassisterad metod med vatten som losningsmedel for att kovalent binda nGO pa ytan av PCL byggnadsstallningar. De initiala nGO koncentrationerna var 0,5 och 1 mg / ml. fourier-transform infrarodspektroskopi (FTIR) och termogravimetrisk analys (TGA) verifierade bindningen mellan de funktionella gruppema pa nGO och de fria aminema. Svepelektronmikroskopi (SEM) visade en homogen fordelning av nGO pa ytan av de porosa byggnadsstallningarna. De mekaniska testema som utfordes demonstrerade · en 50 och 21 % okning av kompressionsstyrkan :for byggnadsstallningarna ympade med de initiala nGO-koncentrationema pa 0,5 och 1 mg / ml. In vitro-mineraliseringstester visade bildandet av mineralfallningar pa ytan av byggnadsstallningama som okade i storlek med hogre nGO-halt. A ven nGO: s potential som nano-barare av ett antibiotikum studerades i detta arbete. Pa grund av sitt overflod av kemiska funktionaliteter kan nGO effektivt adsorbera foreningar genom olika sekundara interaktioner. I denna studie optimerades dessa sekundara interaktioner genom att reglera losningens pH for maximal adsorption av ciprofloxacin, ett bredspektrum antibiotikum som anvands vid behandling av osteomyelit. Ciprofloxacin befanns kunna adsorberas starkast i sin katjonform vid pH 5, dar 1t-1t elektron­donatoracceptor (EDA) -interaktioner dominerar. Sammanfattningsvis bekraftar de resultat som presenteras i detta arbete potentialen hos nGO som egenskapsforbattrare och lakemedelsbarare i applikationer inom vavnadsregenerering.

    The full text will be freely available from 2019-06-08 15:19
  • 347.
    Jeppsson, Fredrik
    et al.
    Innovative Medicines AstraZeneca, CNS and Pain, Södertälje, Sweden; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Sweden.
    Falting, Johanna
    Discovery of AZD3839, a Potent and Selective BACE1 Inhibitor Clinical Candidate for the Treatment of Alzheimer Disease2012In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 287, no 49, p. 41245-41257Article in journal (Refereed)
    Abstract [en]

    beta-Site amyloid precursor protein cleaving enzyme1 (BACE1) is one of the key enzymes involved in the processing of the amyloid precursor protein (APP) and formation of amyloid beta peptide (A beta species. Because cerebral deposition of A beta species might be critical for the pathogenesis of Alzheimer disease, BACE1 has emerged as a key target for the treatment of this disease. Here, we report the discovery and comprehensive preclinical characterization of AZD3839, a potent and selective inhibitor of human BACE1. AZD3839 was identified using fragment-based screening and structure-based design. In a concentration-dependent manner, AZD3839 inhibited BACE1 activity in a biochemical fluorescence resonance energy transfer (FRET) assay, A beta and sAPP beta release from modified and wild-type human SH-SY5Y cells and mouse N2A cells as well as from mouse and guinea pig primary cortical neurons. Selectivity against BACE2 and cathepsin D was 14 and >1000-fold, respectively. AZD3839 exhibited dose-and time-dependent lowering of plasma, brain, and cerebrospinal fluid A beta levels in mouse, guinea pig, and non-human primate. Pharmacokinetic/pharmacodynamic analyses of mouse and guinea pig data showed a good correlation between the potency of AZD3839 in primary cortical neurons and in vivo brain effects. These results suggest that AZD3839 effectively reduces the levels of A beta in brain, CSF, and plasma in several preclinical species. It might, therefore, have disease-modifying potential in the treatment of Alzheimer disease and related dementias. Based on the overall pharmacological profile and its drug like properties, AZD3839 has been progressed into Phase 1 clinical trials in man.

  • 348. Ji, Y.
    et al.
    Ji, X.
    Lu, X.
    Tu, Yongming
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges. Southeast University, China.
    Modeling mass transfer of CO2 in brine at high pressures by chemical potential gradient2013In: Science China Chemistry, ISSN 1674-7291, Vol. 56, no 6, p. 821-830Article in journal (Refereed)
    Abstract [en]

    To investigate long-term CO2 behavior in geological formations and quantification of possible CO2 leaks, it is crucial to investigate the potential mobility of CO2 dissolved in brines over a wide range of spatial and temporal scales and density distributions in geological media. In this work, the mass transfer of aqueous CO2 in brines has been investigated by means of a chemical potential gradient model based on non-equilibrium thermodynamics in which the statistical associating fluid theory equation of state was used to calculate the fugacity coefficient of CO2 in brine. The investigation shows that the interfacial concentration of aqueous CO2 and the corresponding density both increase with increasing pressure and decreasing temperature; the effective diffusion coefficients decrease initially and then increase with increasing pressure; and the density of the CO2-disolved brines increases with decreasing CO2 pressure in the CO2 dissolution process. The aqueous CO2 concentration profiles obtained by the chemical potential gradient model are considerably different from those obtained by the concentration gradient model, which shows the importance of considering non-ideality, especially when the pressure is high.

  • 349. Jiang, J.
    et al.
    Wang, M.
    Yan, W.
    Liu, X.
    Liu, J.
    Yang, J.
    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.
    Highly active and durable electrocatalytic water oxidation by a NiB0.45/NiOx core-shell heterostructured nanoparticulate film2017In: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 38, p. 175-184Article in journal (Refereed)
    Abstract [en]

    On the way to energy-efficient and cost-effective hydrogen production by electrochemical or photoelectrochemical water splitting, it is of primary importance to develop highly active and durable water oxidation electrocatalysts based on earth-abundant elements. Here we report a highly active, robust, cheap, and facilely fabricated O2-evolving catalyst on a Cu foil, NiB0.45-250/Cu, which forms a NiB0.45/NiOx core-shell heterostructured nanoparticulate film during anodic electrolysis. The performance of NiB0.45-250/Cu, to produce 10 mA cm−2 at 296 mV overpotential in 1 M KOH over 60 h, is at par with the best efficiency of earth-abundant electrocatalysts reported to date and surpasses that of IrO2-loaded copper electrode under identical conditions. Experimental evidence and theoretical calculations reveal the correlations of B/Ni atomic ratio and annealing temperature with the morphology, surface microtexture, electrochemical active surface area, and electrical conductivity of NiBx films. Optimal combination of these factors can evidently enhance the catalytic activity of nickel boride electrocatalysts.

  • 350. Jin, Ying
    et al.
    Liu, Min
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. University of Science and Technology Beijing, China.
    Zhang, Chuanhui
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Wen, Lei
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    First-Principle Calculation of Volta Potential of Intermetallic Particles in Aluminum Alloys and Practical Implications2017In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 164, no 9, p. C465-C473Article in journal (Refereed)
    Abstract [en]

    This work presents a theoretical assessment of galvanic (relative) nobility of four intermetallic particles (IMPs), Al2Cu, Al2CuMg, Mg2Si andMgZn(2), in aluminum alloys through work function calculation based on density functional theory (DFT). The concepts of work function, Volta potential and relative nobility are discussed with respect to the IMPs and aluminum matrix. The calculated Volta potentials are compared with reported experimental Volta potentials measured by scanning Kelvin probe forcemicroscopy (SKPFM). Various crystal faces and terminal types are examined in the DFT calculation, showing that these two factors have a significant effect on the work function value. Considering the large divergence in the reported experimental data, the comparison shows a general agreement between the calculated and experimental Volta potential data for the investigated IMPs. The DFT calculations provide theoretical explanations for several experimental phenomena. The results demonstrate that DFT calculation is a valuable theoretical approach for assessment of the relative nobility of different phases in the alloys, providing complementary information to experimental data from SKFPM. Moreover, the implications of the calculated Volta potentials are discussed with respect to the corrosion potentials.

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