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  • 1.
    Bech, Linda
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Genetic and phenotypic characterization of trypanosomas2009Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

     

    Trypanosoma theileri, of the subgenus Megatrypanum, a non-pathogenic cosmopolitan blood dwelling parasite of bovine. T. theileri can be cultured at room temperature in several culture media.

    Blood samples were collected from deer's. To see if the blood was infected with trypanosomes it was cultivated in 2 ml sheep blood or cell cultivation medium DMEM with antibiotics.

    Growth was detected by microscopy to see if there were any trypanosomes.

    To determine the species of trypanosomes that was in the deer blood a DNA-preparation was done before a Polymerase Chain Reaction (PCR) could be done. With sequencing the trypanosomes where determined to be Trypanosoma theileri.

    Different tests were made to see in what way the trypanosomes best were caught to the objective slides.

    Forty samples of borrelia positive serum from forty different patients were tested with the fluorescent microscopy. Forty different samples from blood donors were tested the same way.

    Blood samples from 16 different fissiped were taken and to see if they were infected with trypanosomes. Three different PCR's were done on the 16 blood samples.

    A small test on human blood was also performed.

    Protein identification by immunoblot with western blot and silver staining was done.

    With the electron microscopy tests were done in the ordinary way and Critical Dry Point to see if both of the techniques worked.

    Enzyme-Linked Immuno Sorbent Assay (ELISA) test were accomplished on two 96 well plates. The wells on the plates were diluted in different ways before they were processed.

     

     

  • 2.
    Bergkvist, Magnus
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Carlsson, J
    Uppsala University, Sweden.
    Karlsson, T
    Pharmacia and Upjohn Diagnostics, Sweden.
    Oscarsson, Sven
    Mälardalen University, Department of Biology and Chemical Engineering.
    TM-AFM Threshold Analysis of Macromolecular Orientation: A Study of the Orientation of IgG and IgE on Mica Surfaces.1998In: Journal of Colloid and Interface Science, ISSN 0021-9797, Vol. 206, no 2, p. 475-481Article in journal (Refereed)
    Abstract [en]

    Adsorption and orientation properties of two different types of immunoglobulin molecules on derivatized and native mica surfaces were investigated using TM-AFM. The analyses included height measurements at two different pH values and a new technique, presented here as threshold analysis, which displays the outer mantle shape of an adsorbed protein. A major difference in preferential orientation is observed upon comparing the adsorption of the two proteins onto the different surfaces. The characteristics of both the adsorbed immunoglobulin and the surface are important for any preferential orientation of the adsorbed protein.

  • 3.
    Bergkvist, Magnus
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering. Uppsala University, Sweden.
    Carlsson, Jan
    Uppsala University, Sweden.
    Oscarsson, Sven
    Mälardalen University, Department of Biology and Chemical Engineering. Uppsala University, Sweden.
    Surface-dependent conformations of human plasma fibronectin adsorbed to silica, mica, and hydrophobic surfaces, studied with use of Atomic Force Microscopy2003In: Journal of biomedical materials research. Part A., ISSN 0021-9304, Vol. 64, no 2, p. 349-356Article in journal (Refereed)
    Abstract [en]

    Human plasma fibronectin (Fn) is a large flexible protein stabilized by intermolecular ionic interactions forming a compact structure. On altering solution conditions, the structure can revert to a more expanded state, thereby exposing previously hidden domains (e.g., cell-binding sites). Electron microscopy images of Fn air-sprayed onto mica surfaces show elongated protein structures, indicating a surface-induced structural change. This makes it interesting to investigate the influence of surface properties on the structure of adsorbed Fn. We have used intermittent-contact Atomic Force Microscopy to investigate the structure of Fn adsorbed onto mica, silica, and methylated silica surfaces. We observed that on silica surfaces, which is hydrophilic, most (70%) of the molecules had an elongated structure with partial intramolecular chain interactions, compare to molecules adsorbed on hydrophobic, methylated surfaces, where a compact structure predominated (70%). On mica surfaces, both compact and elongated protein structures were observed, with a slight preference for the elongated form (53%). Results show that surface physical properties influence the molecular structure of fibronectin on adsorption, which could provide useful information in understanding surface-induced in vivo responses.

  • 4.
    Berner, S.
    et al.
    Uppsala University, Sweden.
    Biela, S.
    Uppsala University, Sweden.
    Ledung, G.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Gogoll, A.
    Uppsala University, Sweden.
    Bäckvall, J.E.
    Stockholm University, Sweden.
    Puglia, C.
    Uppsala University, Sweden.
    Oscarsson, S.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Activity boost of a biomimetic oxidation catalyst by immobilization onto a gold surface2006In: Journal of Catalysis, ISSN 0021-9517, Vol. 244, no 1, p. 86-91Article in journal (Refereed)
    Abstract [en]

    Thiol-functionalized cobalt porphyrins were used as a model system for investigating catalytic activity in homogeneous and heterogeneous oxidation catalysis. Self-assembled monolayers of thiol-functionallized cobalt porphyrins were prepared on a gold surface and served as heterogeneous catalysts. These immobilized molecules prevented the strong inactivation observed for their homogeneous congener. As a result, the turnover number per molecule in heterogeneous catalysis was at least 100 times higher than that of the corresponding homogeneous catalyst. It is atypical for a heterogenized catalyst to outperform its homogeneous congener. The properties of the molecular layers were characterized on the molecular level by means of X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM). The results demonstrate that the performance of these biomimetic catalysts can be dramatically improved if the catalyst arrangement can be controlled on the molecular level.

  • 5.
    Berner, S.
    et al.
    Uppsala University, Uppsala, Sweden.
    Lidbaum, H.
    Uppsala University, Uppsala, Sweden.
    Ledung, G.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Åhlund, J.
    Uppsala University, Uppsala, Sweden.
    Nilson, K.
    Uppsala University, Uppsala, Sweden.
    Schiessling, J.
    Uppsala University, Uppsala, Sweden.
    Gelius, U.
    Uppsala University, Uppsala, Sweden.
    Bäckvall, J.
    Stockholm University, Sweden.
    Puglia, C.
    Uppsala University, Uppsala, Sweden.
    Oscarsson, Sven
    Mälardalen University, Department of Biology and Chemical Engineering.
    Electronic and structural studies of immobilized thiol-derivatized cobalt porphyrins on gold surfaces2007In: Applied Surface Science, ISSN 0169-4332, Vol. 253, no 18, p. 7540-7548Article in journal (Refereed)
    Abstract [en]

    The immobilisation of thiol-derivatized cobalt porphyrins on gold surfaces has been studied in detail by means of combined scanning tunnelling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). S-thioacetyl has been used as a protective group for the thiol. Different routes for deprotection of the acetyl groups were performed in acidic and in basic conditions. The results show the formation of monolayer films for the different preparation schemes. The immobilisation of the molecules on the gold surface takes place through the thiol-linkers by the formation of multiple thiolate bonds. In the case of layers formed with protected porphyrins approximately 60% of the linkers are bonded to the gold surface whereas for deprotected layers the amount of bonded linkers is increased up to about 80%. STM measurements revealed that the molecules arrange in a disordered overlayer and do not exhibit mobility on the gold surface. Annealing experiments have been performed in order to test the stability of the porphyrin layers. Disordered patterns have been observed in the STM images after annealing at T= 400 degrees C. XPS revealed that the sulphur content disappeared completely after annealing at T= 180 degrees C and that the molecules did undergo significant modifications.

  • 6.
    Buijs, Jos
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Håkansson, Kristina
    Uppsala University, Sweden.
    Hagman, Charlotte
    Uppsala University, Sweden.
    Håkansson, Per
    Uppsala University, Sweden.
    Oscarsson, Sven
    Mälardalen University, Department of Biology and Chemical Engineering.
    A new method for the accurate determination of the isotopic state of single amide hydrogens within peptides using Fourier transform ion cyclotron resonance mass spectrometry2000In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, Vol. 14, no 19, p. 1751-1756Article in journal (Refereed)
    Abstract [en]

    A new method is presented to accurately determine the probability of having a deuterium or hydrogen atom on a specific amide position within a peptide after deuterium/hydrogen (D/H) exchange in solution. Amide hydrogen exchange has been proven to be a sensitive probe for studying protein structures and structural dynamics. At the same time, mass spectrometry in combination with physical fragmentation methods is commonly used to sequence proteins based on an amino acid residue specific mass analysis. In the present study it is demonstrated that the isotopic patterns of a series of peptide fragment ions obtained with capillary-skimmer dissociation, as observed with a 9.4 T Fourier transform ion cyclotron resonance (FTICR) mass spectrometer, can be used to calculate the isotopic state of specific amide hydrogens. This calculation is based on the experimentally observed isotopic patterns of two consecutive fragments and on the isotopic binomial distributions of the atoms in the residue constituting the difference between these two consecutive fragments. The applicability of the method is demonstrated by following the sequence-specific D/H exchange rate in solution of single amide hydrogens within some peptides.

  • 7.
    Bürger, Raimund
    et al.
    Universidad de Concepción, Concepción, Chile.
    Careaga, Julio
    Lund University, Sweden.
    Diehl, Stefan
    Lund University, Sweden.
    Merckel, Ryan
    University of Pretoria, South Africa.
    Zambrano, Jesús
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Estimating the hindered-settling flux function from a batch test in a cone2018In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 192, p. 244-253Article in journal (Refereed)
    Abstract [en]

    The hindered-settling velocity function for the modelling, simulation and control of secondary settling tanks can be determined from batch tests. The conventional method is to measure the velocity of the descending sludge-supernatant interface (sludge blanket) as the change in height over time in a vessel with constant cross-sectional area. Each such experiment provides one point on the flux curve since, under idealizing assumptions (monodisperse suspension, no wall-effects), the concentration of sludge remains constant just below the sludge blanket until some wave from the bottom reaches it. A newly developed method of estimation, based on the theory of nonlinear hyperbolic partial differential equations, is applied to both synthetic and experimental data. The method demonstrates that a substantial portion of the flux function may be estimated from a single batch test in a conical vessel. The new method takes into consideration that during an ideal settling experiment in a cone, the concentration just below the sludge blanket increases with time since the mass of suspended solids occupy a reduced volume over time.

  • 8.
    Campana, Pietro Elia
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Daianova, L.
    Yan, Jinyue
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Desideri, U.
    Bioethanol Production from Lignocellulosic Biomass, Evaluation of the Potential Bioethanol Production in Three Swedish Regions2009Conference paper (Refereed)
  • 9.
    Cronstrand, P.
    et al.
    Royal Institute of Technology, Sweden.
    Jansik, B.
    Royal Institute of Technology, Sweden.
    Jonsson, D.
    Mälardalen University, Department of Mathematics and Physics. Stockholm University, Sweden.
    Luo, Y.
    Mälardalen University, Department of Mathematics and Physics. Royal Institute of Technology, Sweden.
    Ågren, H.
    Mälardalen University, Department of Mathematics and Physics. Royal Institute of Technology, Sweden.
    Density functional theory calculations of three-photon absorption2004In: Journal of Chemical Physics, ISSN 0021-9606, Vol. 121, no 19, p. 9239-9246Article in journal (Refereed)
    Abstract [en]

    Three-photon absorption probabilities delta(3PA) have been calculated through application of a recently derived method for cubic response functions within density functional theory (DFT). Calculations are compared with Hartree-Fock (HF) and with a coupled cluster hierarchy of models in a benchmarking procedure. Except for cases having intermediate states near resonance, density functional theory is demonstrated to be in sufficient agreement with the highly correlated methods in order to qualify for predictions of delta(3PA). For the larger systems addressed, a set of acceptor A and donor D substituted pi-conjugated systems formed by trans-stilbene and dithienothiophene (DTT), we find noticeable differences in the magnitude of delta(3PA) between HF and DFT, although similar trends are followed. It is shown that the dipolar structures, TS-AD and DTT-AD, have substantially larger delta(3PA) than other types of modifications which is in accordance with observations for two-photon absorption. This is the first application of density functional theory to three-photon absorption beyond the use of few-state models.

  • 10.
    Cronstrand, P.
    et al.
    Royal Institute of Technology, Sweden.
    Norman, P.
    Mälardalen University, Department of Mathematics and Physics. Linköping University, Sweden.
    Luo, Y.
    Royal Institute of Technology, Sweden.
    Ågren, H
    Royal Institute of Technology, Sweden.
    Few-states models for three-photon absorption2004In: Journal of Chemical Physics, ISSN 0021-9606, Vol. 121, no 5, p. 2020-2029Article in journal (Refereed)
    Abstract [en]

    Few-states models are derived for the calculation of three-photon absorption matrix elements. Together with earlier derived few-states models for two-photon absorption, the models are evaluated against results from response theory calculations that provide the full sum-over-states values. It is demonstrated that not even for systems with charge-transfer character, where few-states models for two-photon absorption are in excellent agreement with response theory, do the models provide a quantitatively correct description for three-photon absorption. The convergence behavior, merits, and shortcomings of the models are elucidated in some detail. The role of various characteristics of the electronic structure, such as symmetry, charge transfer, and conjugation-important for the formation of a large three-photon cross section-is analyzed. As for two-photon absorption cross sections, it is essential to consider generalized few-states models also for three-photon absorption, that is, to account for dipolar directions and laser beam polarization. Despite their poor quantitative performance, it is argued that few-states models at times can be useful for interpretation purposes when applied to three-photon absorption. (C) 2004 American Institute of Physics.

  • 11.
    Ell, A.H.
    et al.
    Stockholm University, Sweden.
    Csjernyik, G.
    Stockholm University, Sweden.
    Slagt, V.F.
    Stockholm University, Sweden.
    Bäckvall, J.E.
    Stockholm University, Sweden.
    Berner, S.
    Uppsala University, Sweden.
    Puglia, C
    Uppsala University, Sweden.
    Ledung, G
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Oscarsson, S
    Mälardalen University, School of Sustainable Development of Society and Technology. Uppsala University, Sweden.
    Synthesis of thioacetate-functionalized cobalt(II) porphyrins and their immobilization on gold surface - Characterization by X-ray photoelectron spectroscopy2006In: European Journal of Organic Chemistry, ISSN 1434-193X, no 5, p. 1193-1199Article in journal (Refereed)
    Abstract [en]

    Cobalt tetraarylporphyrins 1-Co and 2-Co with thioacetate-functionalized carbon chains on the aryl groups were synthesized. The cobalt porphyrin 2-Co was immobilized on a gold surface after deprotection of the S-acetyl group. The immobilized porphyrin was studied by X-ray Photoelectron Spectroscopy (XPS) and the results suggest that a complete monolayer of porphyrins is formed.

  • 12.
    Farooq, Usman
    et al.
    East China Univ Sci & Technol, China..
    Danish, Muhammad
    East China Univ Sci & Technol, China..
    Lu, Shuguang
    East China Univ Sci & Technol, China..
    Naqvi, Muhammad
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Gu, Xiaogang
    East China Univ Sci & Technol, China..
    Fu, Xiaro
    East China Univ Sci & Technol, China..
    Zhang, Xiang
    East China Univ Sci & Technol, China..
    Nasir, Muhammad
    COMSATS Inst Informat Technol, IRCBM, Lahore, Pakistan..
    Synthesis of nZVI@reduced graphene oxide: an efficient catalyst for degradation of 1,1,1-trichloroethane (TCA) in percarbonate system2017In: Research on chemical intermediates (Print), ISSN 0922-6168, E-ISSN 1568-5675, Vol. 43, no 5, p. 3219-3236Article in journal (Refereed)
    Abstract [en]

    Graphene-oxide-supported nano zero-valent iron (nZVI) composite (nZVI-rGO) was synthesized and tested as an efficient percarbonate activator for degradation of 1,1,1-trichloroethane (TCA). Significant dispersion of nZVI on the surface of reduced graphene oxide (rGO) was observed, with good limitation of nanoparticle agglomeration and aggregation. Good TCA degradation efficiency of 90% was achieved in 2.5 h in presence of 0.8 g/l nZVI-rGO catalyst and 30 mM sodium percarbonate (SPC) oxidant; however, excessive catalyst or oxidant concentration reduced the degradation efficiency. Investigation of reactive oxygen species using radical probe compounds as well as radical scavengers confirmed presence of hydroxyl (OH center dot) and superoxide () radicals that are responsible for the TCA degradation. The morphology and surface characteristics of the heterogeneous catalyst were analyzed by transmission electron microscopy and scanning electron microscopy. Brunauer-Emmett-Teller analysis revealed that the synthesized catalyst had large surface area and small particle size of 299.12 m(2)/g and 20.10 nm, respectively, compared with 5.33 m(2)/g and 1.12 A mu m for bare graphene oxide. X-ray diffraction analysis revealed good dispersion of nZVI on the surface of rGO. Fourier-transform infrared characteristic peaks confirmed strong attachment of Fe onto the rGO surface. Energy-dispersive spectroscopy analysis validated the stoichiometric composition of the prepared Fe/rGO material. In conclusion, use of nZVI-rGO-activated SPC could represent an alternative technique for remediation of TCA-contaminated groundwater.

  • 13.
    Grandin, Anna
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Synthetic Routes towards 2-thia-7,8-diaza-cyclopenta[l]phenanthrene and 1-thia-7,8-diaza-cyclopenta[l]phenanthrene for Molecular Electronics Applications2009Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Electric current is known to flow through the π-bonds in oligothiophenes. In order to use them as molecular wires it is important to use a technique where the potential gradients can be generated and maintained in supramolecular networks. A solution to this problem can be the use of metal complexes as junction points within such a network.

     In this project pathways to synthesize 2-thia-7,8-diaza-cyclopenta[l]phenanthrene (1) and 1-thia-7,8-diaza-cyclopenta[l]phenanthrene (2) for use in molecular electronic devices have been investigated. 4-(5-Bromo-thiophen-2-yl)2,2’-bipyridine (3) was prepared via Kröhnke reaction from 3-(5-bromothiophene-2-yl)acrolein and 1-(2-Oxo-2-pyridine-2-yl-ethyl)-pyridinium iodide in an overall yield of 14 %.  

     Several routes towards 2-thia-7,8-diaza-cyclopenta[l]phenanthrene (1) and 1-thia-7,8-diaza-cyclopenta[l]phenanthrene (2) were tested. Since the original planned pathway did not work, lack of time made it impossible to complete the series of experiments that were needed. The synthesis of 2-thia-7,8-diaza-cyclopenta[l]phenanthrene (1) is almost finished. Due to the solvation problems, after the decarboxylation step, the product could not be analyzed by 1H-NMR in a satisfactory manner. The product was sent for analysis.

     A number of experiments towards 1-thia-7,8-diaza-cyclopenta[l]phenanthrene (2) were tested but few of them worked as planned. There is a lot of work left to be done in the synthesis of this compound but the lack of time made it impossible.

     The chemistry that has been achieved is the synthesis of 1,10-phenanthroline-5,6-dione in the synthesis of 2-thia-7,8-diaza-cyclopenta[l]phenanthrene (1). The following Hinsberg thiophene synthesis probably worked but due to solvation problems the product could not be isolated. The final product after hydrolysis and decarboxylation of the remaining ester groups after the Hinsberg thiophene synthesis was tested but the results were difficult to confirm.

     In the synthesis of 1-thia-7,8-diaza-cyclopenta[l]phenanthrene (2) several attempts to make 3,4-diamino-N,N-diethyl-benzamide were made. The attack from the primary amines on the carbonyl carbon made it necessary to protect them. The attempt to synthesize 3,4-bis-acetylamino-N,N-diethyl-benzamide also failed, both the attempt directly from the carboxylic acid and through the acylchloride, even though the amines were protected.  

  • 14.
    Gunnarsson, K
    et al.
    Uppsala University, Sweden.
    Roy, P.E.
    Uppsala University, Sweden.
    Felton, S.
    Uppsala University, Sweden.
    Pihl, J.
    Uppsala University, Sweden.
    Svedlindh, P.
    Uppsala University, Sweden.
    Berner, S
    Mälardalen University, Department of Biology and Chemical Engineering. Uppsala University, Sweden.
    Lidbaum, H.
    Uppsala University, Sweden.
    Oscarsson, S
    Mälardalen University, Department of Biology and Chemical Engineering. Uppsala University, Sweden.
    Programmable motion and separation of single magnetic particles on patterned magnetic surfaces2005In: Advanced Materials, ISSN 0935-9648, Vol. 17, no 14, p. 1730-1734Article in journal (Refereed)
    Abstract [en]

    Motion of single micrometer-sized magnetic particles on patterned magnetic surfaces is controlled by a rotating magnetic field (see Figure and cover). Patterns of thin-film magnetic elements are tailored to form transport lines. Individual particles are separated by adding junctions to the transport lines. The method can improve existing applications in biotechnology and generate new ones in life sciences.

  • 15.
    Guo, K.
    et al.
    Univ Stavanger, Norway.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Yu, Zhixin
    Univ Stavanger, Norway.
    Size-Dependent Catalytic Activity of Monodispersed Nickel Nanoparticles for the Hydrolytic Dehydrogenation of Ammonia Borane2018In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 1, p. 517-525Article in journal (Refereed)
    Abstract [en]

    Nickel (Ni) nanoparticles (NPs) with controlled sizes in the range of 4.9-27.4 nm are synthesized by tuning the ratio of the nickel acetylacetonate precursor and trioctylphosphine in the presence of oleylamine. X-ray diffraction and transmission electron microscopy confirm the formation of the metallic Ni crystal phase and their monodispersed nature. These Ni NPs are found to be effective catalysts for the hydrolytic dehydrogenation of ammonia borane, and their catalytic activities are size-dependent. A volcano-type activity trend is observed with 8.9 nm Ni NPs presenting the best catalytic performance. The activation energy and turnover frequency (TOF) of the 8.9 nm NP catalyst are further calculated to be 66.6 kJ·mol-1 and 154.2 molH2·molNi -1·h-1, respectively. Characterization of the spent catalysts indicates that smaller-sized NPs face severe agglomeration, resulting in poor stability and activity. Three carbon support materials are thus used to disperse and stabilize the Ni NPs. It shows that 8.9 nm Ni NPs supported on Ketjenblack (KB) exhibit higher activity than that supported on carbon nanotubes and graphene nanoplatelets. The agglomeration-induced activity loss is further illustrated by immobilizing 4.9 nm Ni NPs onto KB, which exhibits significantly enhanced activity with a high TOF of 447.9 molH2·molNi -1·h-1 as well as an excellent reusability in the consecutive dehydrogenation of ammonia borane. The high catalytic performance can be attributed to the intrinsic activity of nanoparticulate Ni and the improved activity and stability due to the strong Ni/KB metal-support interactions.

  • 16. Jönsson, Mats
    et al.
    Aldaeus, Fredrik
    Johansson, LarsErik
    Lindberg, Ulf
    Roeraade, Johan
    Hamp, Sven
    Jonsson, Gunnar
    A Simple Open Micro System for Dielectrophoresis and Impedance MeasurementsManuscript (preprint) (Other academic)
  • 17.
    Karlsson, Anders
    et al.
    Gothenburg University, Sweden.
    Karlsson, Roger
    Gothenburg University, Sweden.
    Karlsson, Mattias
    Gothenburg University, Sweden.
    Cans, Annsofie
    Gothenburg University, Sweden.
    Strömberg, Anette
    Gothenburg University, Sweden.
    Ryttsén, Frida
    Gothenburg University, Sweden.
    Orwar, Owe
    Chalmers University of Technology, Sweden.
    Molecular engineering: Networks of nanotubes and containers2001In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 409, no 6817, p. 150-152Article in journal (Refereed)
  • 18.
    Kindmark, Maria
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Laborationers inverkan på elevers intresse för kemi2011Independent thesis Advanced level (professional degree), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    Syftet med undersökningen var att komma fram till hur man med hjälp av laborationer kan entusiasmera elever till att bli intresserade av kemi. Undersökningen utfördes i form av en enkät bland elever på gymnasiet (år 1-3). Enkäten hade en öppen struktur med dels öppna frågor men även frågor med flervalsalternativ. Elevsvaren har sammanställts i kategorier och diskuteras utifrån aktuell forskning. Resultatet visade att gymnasieeleverna efterfrågar laborationer med tydlig koppling till vardagen. De efterfrågar också en tydlig koppling mellan teori och laboration. Eleverna gav också uttryck för att det är viktigt med kunskaper i kemi för att påverka utvecklingen i framtiden samt kunna granska vad som skrivs och sägs i media. En slutsats av undersökningen är att man i elevgruppen finner elever med en inställning som tyder på att kemi anses som viktigt, men att man som lärare måste koppla laborationerna till såväl elevernas vardag som till teorin. Det innebär att en laboration om t.ex. syror och baser kan leda till att eleven lär sig såväl om försurning som om den mer teoretiska delen av kemin. För att sådana laborationer ska bli genomförbara krävs det noggrann förberedelse av läraren. Det är också viktigt i samband med laborationer att det förs diskussioner kring experimentets slutsats så att eleven med hjälp av t.ex. laborationen om syror och baser kan förklara försurning och hur det påverkar naturen, men även få stöd i sin teoretiska förståelse för syra-basreaktioner. På så sätt kan eleven använda sig av sin nyvunna kunskap från laborationen i ett större sammanhang.

  • 19.
    Larsericsdotter, Helén
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Oscarsson, Sven
    Mälardalen University, Department of Biology and Chemical Engineering.
    Buijs, Jos
    Mälardalen University, Department of Biology and Chemical Engineering. Uppsala University, Sweden.
    Thermodynamic analysis of lysozyme adsorbed to silica2004In: Journal of colloid and interface science, ISSN 0021-9797, Vol. 276, no 2, p. 261-268Article in journal (Refereed)
    Abstract [en]

    The structural stability of hen egg white lysozyme in solution and adsorbed to small colloidal silica particles at various surface concentrations was investigated using hydrogen-deuterium (H/D) exchange in combination with mass spectrometry (HDX-MS) and differential scanning calorimetry (DSC). The combination of HDX-MS and DSC allows a full thermodynamic analysis of the lysozyme structure as both the enthalpy and the Gibbs free energy can be derived from the various measurements. Moreover, both HDX-MS and DSC provide information on the relative structural heterogeneity of lysozyme in the adsorbed state compared to that in solution. Results demonstrated that at high surface coverage, the structural stability of lysozyme was only marginally affected by adsorption to silica particles whereas the unfolding enthalpy decreased by more than 10%, meaning that the entropy of lysozyme increased with a similar value upon adsorption. Furthermore, the structural heterogeneity increased considerably. At lower surface concentrations, the structural heterogeneity increased further whereas the enthalpy of unfolding decreased. Further analyses of the HDX-MS experiments clearly indicated that folding/unfolding of lysozyme occurs through a two-domain process. These two domains had a similar amount of structural elements and a difference in stabilization energy of 8 kJ/mol, regardless if lysozyme was in solution or adsorbed to silica.

  • 20.
    Larseriksdotter, Helén
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Oscarsson, S
    Mälardalen University, Department of Biology and Chemical Engineering.
    Buijs, J
    Biacore AB, Sweden.
    Structure Stability and Orientation of BSA Adsorbed to Silica2005In: Journal of Colloid and Interface Science, ISSN 0021-9797, Vol. 289, no 1, p. 26-35Article in journal (Other (popular science, discussion, etc.))
    Abstract [en]

    In this investigation, the structure, stability, and orientation of bovine serum albumin (BSA) adsorbed onto silica particles were studied using differential scanning calorimetry (DSC) and limited proteolysis in combination with mass spectrometry (MS). DSC gave information on the overall structural stability of BSA while limited proteolysis was used to probe the accessibility of enzymatic cleavage sites, thereby yielding information on the orientation and structure of BSA adsorbed to silica surfaces. Thermal investigation of BSA in various buffers, both free in solution and in the adsorbed state, showed that solutes that surround the protein played an important role with respect to the overall structural stability and the structural heterogeneity of BSA. Limited proteolysis with trypsin and chymotrypsin indicated that BSA in the adsorbed state is oriented with domain 2 facing the silica surface. Also, upon adsorption, no additional cleavage sites were exposed. The combination of the results presented in this study implied that BSA molecules adsorbed onto silica particles were significantly reduced in their structural stability, but not to an extent that internal residues within the nativP structure became fully exposed to the solution.

  • 21.
    Ledung, G.
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Bergkvist, M.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Quist, A.P.
    Uppsala University, Sweden.
    Gelius, U.
    Uppsala University, Sweden.
    Carlsson, J.
    Uppsala University, Sweden.
    Oscarsson, S.
    Uppsala University, Sweden.
    Novel method for preparation of disulfides on silicon2001In: Langmuir, ISSN 0743-7463, Vol. 17, no 2, p. 6056-6058Article in journal (Refereed)
    Abstract [en]

    This work describes an efficient novel method to incorporate reactive disulfide bonds onto a silica surface under mild reaction conditions. The reactive thiol groups introduced onto the silicon surface in the first reaction step will be oxidized but easily converted into highly reactive thiopyridyl groups, which can therefore easily be utilized for further organic synthesis involving thiol-containing molecules. This is done in a way that yields approximately a monolayer of reactant on the surface, thereby not adding to the roughness of the surface, of special importance, for instance, for single molecule interaction studies.

  • 22.
    Ledung, G.
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Gothelid, E.
    Berner, S.
    Backvall, J.E.
    Puglia, C.
    Oscarsson, S.
    The performance of a biomimetic oxidation catalyst immobilized on silicon wafers: A comparison with the catalyst in solution and immobilized on goldManuscript (Other academic)
  • 23.
    Malmberg, Jennie
    Mälardalen University, School of Sustainable Development of Society and Technology.
    The neuroanatomical  expression profile of novel  membrane proteins.: The effect of macronutrients on gene expression.2008Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    Worldwide obesity is an increasing problem. Apart from the fact that obesity greatly  impairs the health, quality and length of life for the affected individuals, it is also has the  potential to become a major socioeconomic problem in a near future. However preventive  actions require an understanding of the cause. Before the psychological influence on  eating can be evaluated a profound understanding of the biological regulatory system and  how this interacts with the food consumed is required. On the assumption that food  consumption is regulated by interplay between food and genes, the food itself may  influence the genes that regulate consumption, hence change the expression levels of the  genes regulating food intake.     To evaluate the interplay between food and gene expression, the project contained several  parts, reflecting different aspects of the area of research. The feeding studies had in  common that they were initial trials in a larger project. The results of these will be  evaluated and used in combination with further studies.     The mice typed for food preference illustrate the complexity of the feeding regulatory  system by pointing out the differences between individuals even in a relatively small  group of animals. Mice in general like food high in fat and here the animals that showed a  preference for sugar also showed a significant increase in their intake of chow. Since  chow consists mainly of carbohydrates the results might indicate a preference not for  sucrose in particular but for carbohydrates in general. The effect this may have on other  studies is still unclear as further studies are needed to determine whether the difference  may be the result of an innate genetic difference.      Leucine has been previously shown to reduce the total caloric intake. When given in  combination with palatable food the addition of Leucine primarily reduced the intake of  chow. From a dietary perspective this would translate to a preference to sweets and fast  food at the expense of food with more nutritious content.     The RT-PCR analysis’s gives clues to how the energy regulatory circuitry responds to the  intake of selected macronutrients. When it comes to gene expression there is a significant  effect of macronutrients on the gene expression levels. The common theme for many of  the genes tested seems to be down regulation of satiety signals, as if to support over  feeding on palatable diets and in many cases sucrose in particular.     The intake of macronutrients such as sugar or fat has been showed to have an effect on  the feeding regulatory circuitry, demonstrated by the change in gene expression levels.   The response to said macronutrients is site specific which is clearly shown both by RTPCR analysis of samples from different parts of the brain, such as the brainstem or  hypothalamus, and by immunohistochemistry of selected areas. The  immunohistochemistry also confirms that the novel Oxytocin receptor-antagonist, who is  injected IP, actually passes over the blood-brain barrier and has an actual affect on the  regions of interest. The areas affected by the antagonist can be visualized and identified  through the staining of active sites.

  • 24.
    Nurkkala, Lasse J.
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Malmquist, Jenny K.
    Uihero, Jaana
    Ryytty, Rebecca B.
    Dunne, Simon J.
    Use of Heck Methodology for the formation of Mono- and Di-pyridyl ThienopyridinesManuscript (Other academic)
  • 25.
    Nurkkala, Lasse J.
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Steen, Robert O.
    Hougen, I. A.
    Schmitt, C. X.
    Constable, E. C.
    Bernhardt, P. V.
    Dunne, S. J.
    Coordination-mode pH and Light-activated Molecular Switches based on Ruthenium(II) Oligopyridine Complex ArchitectureManuscript (Other academic)
  • 26.
    Nurkkala, Lasse
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Steen, Robert
    Mälardalen University, Department of Biology and Chemical Engineering.
    Friberg, Henrik
    Mälardalen University, Department of Biology and Chemical Engineering.
    Häggström, Johanna
    Mälardalen University, Department of Biology and Chemical Engineering.
    Bernhardt, Paul
    Riley, Mark
    Dunne, Simon
    Mälardalen University, Department of Biology and Chemical Engineering.
    The effects of pendant vs. fused thiophene attachment upon the luminescence lifetimes and electrochemistry of tris(2,2 '-bipyridine)ruthenium(II) complexes2008In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 26, p. 4101-4110Article in journal (Refereed)
    Abstract [en]

    The electrochemical and photophysical properties for a range of ruthenium(II) tris-2,2’-bipyridine complexes in which a thiophene substituent is attached to one of the bipyridine ligands via either a pendant or a fused mode have been determined. The fused mode of attachment eliminates torsional movement between the thiophene unit and the chelating bipyridine, thereby offering optimal overlap between the p systems of the chelating unit and the attached thiophene unit. The electrochemical properties of these complexes were found to be similar, however the luminescence lifetimes and intensities (in CH3CN at room temperature) were found to be correlated to the mode of attachment. The longest luminescence lifetime was

    observed for the complex [Ru(bpy)2(4-thiophen-2-yl-[2,2']-bipyridine)]2+ (3000 ns), as compared to the prototypic [Ru(bpy)3]2+ (1745 ns). This complex also had the highest quantum yield (0.045). In the four isomeric complexes where the thiophene ring was fused to the b or c face of the pyridine the lifetimes fell in the interval 275-1510 ns and the quantum yield ranged between 0.0047-0.014.

     

    (© WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

  • 27.
    Olofsson, J.
    et al.
    Chalmers University of Technology, Sweden.
    Levin, M.
    Cellectricon AB, Sweden.
    Strömberg, A
    Cellectricon AB, Sweden.
    Weber, S.G
    University of Pittsburgh, USA.
    Ryttsén, F.
    Cellectricon AB, Sweden.
    Orwar, O.
    Chalmers University of Technology, Sweden.
    Generation of focused electric field patterns at dielectric surfaces2005In: Anal.Chem, Vol. 77, no 14, p. 4667-4672Article in journal (Other (popular science, discussion, etc.))
    Abstract [en]

    We here report on a concept for creating well-defined electric field gradients between the boundaries of capillary electrode (a capillary of a nonconducting material equipped with an interior metal electrode) outlets, and dielectric surfaces. By keeping a capillary electrode opening close to a boundary between a conducting solution and a nonconducting medium, a high electric field can be created close to the interface by field focusing effects. By varying the inner and outer diameters of the capillary, the span of electric field strengths and the field gradient obtained can be controlled, and by varying the slit height between the capillary rim and the surface, or the applied current, the average field strength and gradient can be varied. Field focusing effects and generation of electric field patterns were analyzed using finite element method simulations. We experimentally verified the method by electroporation of a fluorescent dye (fluorescein diphosphate) into adherent, monolayered cells (PC-12 and WSS-1) and obtained a pattern of fluorescent cells corresponding to the focused electric field.

  • 28.
    Olofsson, Jessica
    et al.
    Chalmers University of Technology, Gothenburg, Sweden .
    Levin, Mikael
    Cellectricon AB, Gothenburg, Sweden.
    Strömberg, Anette
    Cellectricon AB, Gothenburg, Sweden.
    Weber, Stephen
    University of Pittsburgh, United States.
    Ryttsén, Frida
    Cellectricon AB, Gothenburg, Sweden.
    Orwar, Owe
    Chalmers University of Technology, Gothenburg, Sweden .
    Scanning electroporation of selected areas of adherent cell cultures2007In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 79, no 12, p. 4410-4418Article in journal (Refereed)
    Abstract [en]

    We present a computer-controlled scanning electroporation method. Adherent cells are electroporated using an electrolyte-filled capillary in contact with an electrode. The capillary can be scanned over a cell culture and locally deliver both an electric field and an electroporation agent to the target area without affecting surrounding cells. The instantaneous size of the targeted area is determined by the dimensions of the capillary. The size and shape of the total electroporated area are defined by these dimensions in combination with the scanning pattern. For example, striped and serpentine patterns of electroporated cells in confluent cultures can be formed. As it is easy to switch between different electroporation agents, the method is suitable for design of cell cultures with complex composition. Finite element method simulations were used to study the spatial distributions of the electric field and the concentration of an electroporation agent, as well as the fluid dynamics related to scanning and flow ofelectroporation agent from the capillary. The method was validated for transfection by introduction of a 9-base-pair-long randomized oligonucleotide into PC12 cells and a pmaxGFP plasmid coding for green fluorescent protein into CHO and WSS cells.

  • 29.
    Oscarsson, Sven
    Mälardalen University, Department of Biology and Chemical Engineering.
    Factors affecting protein interaction at sorbent interfaces1997In: Journal of Chromatography B: Biomedical Applications, ISSN 1572-6495, Vol. 699, no 1-2, p. 117-131Article in journal (Refereed)
    Abstract [en]

    Interactions between surfaces and macromolecules are the fundamentals in separation and detection of diverse solutes. In this very brief review the central aspects of protein-surface interactions are discussed with the intention of identifying the important factors influencing such processes and placing them in relation to the established knowledge in this field. Some perspectives of new techniques related to scanning probe microscopy for studying interactions at the nanometer level are also discussed.

  • 30.
    Oscarsson, Sven
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Kårsnäs, Per
    PerCreative, Gothenburg, Sweden.
    Salt-promoted adsorption of proteins onto amphiphilic agarose-based adsorbents. II. Effects of salt and salt concentration1998In: Journal of Chromatography A, ISSN 0021-9673, Vol. 803, no 1-2, p. 83-93Article in journal (Refereed)
    Abstract [en]

    The effects of different types of salts and salt concentrations on the selectivity in the adsorption of serum proteins have been compared for the amphiphilic agarose-based adsorbents Phenyl-Sepharose, Octyl-Sepharose, butyl-agarose and mercaptopyridine-derivatized agarose. By use of multivariate analysis, the complex interrelationships for the different combined effects were evaluated. From these analyses conclusions about similarities and/or dissimilarities in the mechanisms involved in adsorption of proteins on respective adsorbent were made.

  • 31. Quist, Arjan P.
    et al.
    Pavlovic, Elisabeth
    Oscarsson, Sven
    Mälardalen University, Department of Biology and Chemical Engineering.
    Recent advances in microcontact printing2005In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 381, no 3, p. 591-600Article in journal (Refereed)
    Abstract [en]

    Microcontact printing is a remarkable surface patterning technique. Developed about 10 years ago, it has triggered enormous interest from the surface science community, as well as from engineers and biologists. The last five years have been rich in improvements to the microcontact printing process itself, as well as in new technical innovations, many designed to suit new applications. In this review, we describe the evolution of microcontact printing over the past five years. The review is categorized into three main sections: the improvements made to the technique, new variations, and new applications.

  • 32.
    Saarinen, Gabrielle
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Development of Synthetic Routes for Preparation of 2,6-Disubstituted Spiro[3.3]heptanes.2009Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    2,6-Disubstituted spiro[3.3]heptanes were synthesized to investigate and develop synthetic methods for preparation of these compounds. Possibilities for introducing different functionalities like nitriles and sulfonamides were also investigated.

     

    Synthetic routes presented describe successive [2+2] cycloadditions between dichloroketene and olefins to give the sought after spiro compounds with low to moderate yields throughout the multi-step synthesis. [2+2] Cycloadditions offered low turnovers and chromatography was required for purification.

     

    A synthetic route with cyclisations through double substitution reactions between di-electrophiles and di-nucleophiles resulting in a 2,6-disubstituted spiro[3.3]heptane is also described. This multi-step synthesis offered higher turnover and yields and often there was no need for purification through chromatography.

  • 33.
    Skvaril, Jan
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Avelin, Anders
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Odlare, Monica
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Dahlquist, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Fast Determination of Fuel Properties in Solid Biofuel Mixtures by Near Infrared Spectroscopy2017In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 105, p. 1309-1317Article in journal (Refereed)
    Abstract [en]

    This paper focuses on the characterization of highly variable biofuel properties such as moisture content, ash content and higher heating value by near-infrared (NIR) spectroscopy. Experiments were performed on different biofuel sample mixtures consisting of stem wood chips, forest residue chips, bark, sawdust, and peat. NIR scans were performed using a Fourier transform NIR instrument, and reference values were obtained according to standardized laboratory methods. Spectral data were pre-processed by Multiplicative scatter correction correcting light scattering and change in a path length for each sample. Multivariate calibration was carried out employing Partial least squares regression while absorbance values from full NIR spectral range (12,000–4000 cm-1), and reference values were used as inputs. It was demonstrated that different solid biofuel properties can be measured by means of NIR spectroscopy. The accuracy of the models is satisfactory for industrial implementation towards improved process control. 

  • 34.
    Skvaril, Jan
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Dahlquist, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Applications of near-infrared spectroscopy (NIRS) in biomass energy conversion processes: A review2017In: Applied spectroscopy reviews (Softcover ed.), ISSN 0570-4928, E-ISSN 1520-569X, Vol. 52, no 8, p. 675-728Article in journal (Refereed)
    Abstract [en]

    Biomass used in energy conversion processes is typically characterized by high variability, making its utilization challenging. Therefore, there is a need for a fast and non-destructive method to determine feedstock/product properties and directly monitor process reactors. The near-infrared spectroscopy (NIRS) technique together with advanced data analysis methods offers a possible solution. This review focuses on the introduction of the NIRS method and its recent applications to physical, thermochemical, biochemical and physiochemical biomass conversion processes represented mainly by pelleting, combustion, gasification, pyrolysis, as well as biogas, bioethanol, and biodiesel production. NIRS has been proven to be a reliable and inexpensive method with a great potential for use in process optimization, advanced control, or product quality assurance.

  • 35.
    Steen, Robert
    Mälardalen University, Department of Biology and Chemical Engineering.
    The Synthesis of Molecular Switches Based Upon Ru(II) Polypyridyl Architecture for Electronic Applications2007Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    According to the famous axiom known as Moore’s Law the number of transistors that can be etched on a given piece of silicon, and therefore the computing power, will double every 18 to 24 months. For the last 40 years Moore’s prediction has held true as computers have grown more and more powerful. However, around 2020 hardware manufac-turers will have reached the physical limits of silicon. A proposed solution to this dilemma is molecular electronics. Within this field researchers are attempting to develop individual organic molecules and metal complexes that can act as molecular equivalents of electronic components such as diodes, transistors and capacitors. By utilizing molecular electronics to construct the next generation of computers processors with 100,000 times as many components on the same surface area could potentially be created.

    We have synthesized a range of new pyridyl thienopyridine ligands and compared the electrochemical and photophysical properties of their corresponding Ru(II) complexes with that with the Ru(II) complexes of a variety of ligands based on 6-thiophen-2-yl-2,2´-bipyridine and 4-thiophen-2-yl-2,2´-bipyridine. While the electrochemistry of the Ru(II) complexes were similar to that of unsubstituted [Ru(bpy)3]2+, substantial differences in luminescence lifetimes were found. Our findings show that, due to steric interactions with the auxiliary bipy-ridyl ligands, luminescence is quenched in Ru(II) complexes that in-corporate the 6-thiophen-2-yl-2,2´-bipyridine motif, while it is on par with the luminescence of [Ru(bpy)3]2+ in the Ru(II) complexes of the pyridyl thienopyridine ligands. The luminescence of the Ru(II) com-plexes based on the 4-thiophen-2-yl-2,2´-bipyridine motif was en-hanced compared to [Ru(bpy)3]2+ which indicates that complexes of this category are the most favourable for energy/electron-transfer sys-tems.

    At the core of molecular electronics are the search for molecular ON/OFF switches. We have synthesized a reversible double cyclome-tallated switch based on the Ru(tpy) complex of 3,8-bis-(6-thiophen-2-yl-pyridin-2-yl)-[4,7]phenanthroline. Upon treatment with acid/base the complex can be switched between the cyclometallated and the S-bonded form. This prototype has potentially three different states which opens the path to systems based on ternary computer logic.

  • 36.
    Steen, Robert O.
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Nurkkala, Lasse J.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Angus-Dunne, Sarah J.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Schmitt, Chantal X.
    University of Basel, Switzerland.
    Constable, Edwin C.
    University of Basel, Switzerland.
    Riley, Mark J.
    University of Queensland, Australia.
    Bernhardt, Paul V.
    University of Queensland, Australia.
    Dunne, Simon J.
    Mälardalen University, Department of Biology and Chemical Engineering.
    The role of isomeric effects on the luminescence lifetimes and electrochemistry of oligothienyl-bridged dinuclear tris(2,2′-bipyridine) ruthenium(II) complexes2008In: European Journal of Inorganic Chemistry, ISSN 1434-1948, no 11, p. 1784-1794Article in journal (Refereed)
    Abstract [en]

    The luminescence lifetimes (in CH 3CN at room temperature) and electrochemical potentials (in CH 3CN) of a range of mono- and bis(bidentate) 2,2′-bipyridine-capped oligothiophene-bridged Ru II complexes based on the 6-(2-thienyl)-2,2′-bipyridine and 4-(2-thienyl)-2,2′-bipyridine motifs have been measured. The redox potentials occurred in a very narrow range and showed only small shifts from that of [Ru(bpy) 3] 2+, which indicates that the inductive effects of the substituents on the 2,2′-bipyridine ligands are very similar across this series. In the complexes that incorporated a bithiophene moiety the oxidation of the bithienyl group occurred at higher potentials than the metal-centered Ru III/II oxidation. No or very weak interaction between the metal cores in the dinuclear complexes was observed. It was found that the luminescence lifetimes of the complexes where the attachment point of the oligothiophene bridge is in the 4-position of a 2,2′-bipyridine ligand were extended compared to [Ru(bpy) 3] 2+, whereas the luminescence was very short-lived (<30 ns) or completely quenched in the complexes where the oligothiophene bridge was attached in the 6-position. The difference in lifetimes is probably due to steric interactions between the thienyl bridge and the auxiliary bipyridyl ligands, resulting in disturbances in coordination symmetry of the metal core.

  • 37.
    Steen, Robert O.
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Nurkkala, Lasse J.
    Bernhardt, Paul V.
    University of Queensland, Dept. of Chemistry, School of Molecular & Microbial Sciences .
    Dunne, Simon J.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Bis-cyclometallated Molecular Switches Based on 4,7-phenantroline and 1,5-naphthyridine ArchitectureManuscript (preprint) (Other academic)
    Abstract [en]

    Two new bis-terdentate ligands,  3,8-bis-(6-thiophen-2-yl-pyridin-2-yl)-[4,7]phenanthroline (L1) and 2,6-bis(6-(thiophen-2-yl)pyridin-2-yl)-1,5-naphthyridine (L2), capable of reversible double cyclometallation have been synthesized. Both syntheses proceeded via a Skraup synthesis followed by Stille cross-coupling with 2-thiophen-2-yl-6-tributylstannylpyridine to yield the final product. The Ru2(tpy)2-complex of L1 was shown to be capable of reversible cyclometallation, where the bis-cyclometallated (C,C) isomer of the complex had an oxidation potential of +249 mV while the oxidation potential of the doubly S-coordinated (S,S) complex was +987 mV. No ground state interaction between the Ru cores was however found. In theory the complex should display a third, mixed, state. An S,C-coordinated isomer would open the way for molecular electronic applications based on ternary logic. However, despite attempts the S,C-coordinated complex could not be generated.

  • 38.
    Steen, Robert O.
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Nurkkala, Lasse J.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Bernhardt, Paul V.
    University of Queensland, Dept. of Chemistry, School of Molecular & Microbial Sciences .
    Dunne, Simon J.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Synthesis of the Pyridyl Thienopyridine Ligands 5-phenyl-7-(pyridin-2-yl)-thieno[2,3-c]pyridine, 7-(pyridin-2-yl)-5-(thiophen-2-yl)­thieno­[2,3-c]­­pyridine and 5,7-di(pyridin-2-yl)thieno[2,3-c]pyridine via the Hurtley ReactionManuscript (preprint) (Other academic)
    Abstract [en]

    The tridentate thienopyridines 5-phenyl-7-(pyridin-2-yl)thieno[2,3-c]pyridine (L1), 7-(pyridin-2-yl)-5-(thiophen-2-yl)thieno[2,3-c]pyridine (L2) and 5,7-di(pyridin-2-yl)thieno[2,3-c]pyridine (L3) have been synthesized via the Hurtley reaction. L1 and L2 were synthesized by condensing 3-bromothiophene-2-carboxylic acid with phenyl-1,3-butanedione and 1-thienyl-1,3-butanedione respectively. L3 was synthesized by condensing 3-bromothiophene-2- carboxylic acid with benzoylacetonitrile. Ring closure and a subsequent Negishi or Stille cross-coupling afforded L1, L2 and L3 in an overall yield of 20%, 3% and 6% respectively. The corresponding [Ru(tpy)L]n+ complexes were prepared and their electrochemical and structural properties were examined.

  • 39.
    Steen, Robert O.
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Nurkkala, Lasse J.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Hougen, Annett I.
    University of Basel, Dept. of Chemistry.
    Schmitt, Chantal X.
    University of Basel, Dept. of Chemistry.
    Constable, Edwin C.
    University of Basel, Dept. of Chemistry.
    Rees, David G. F.
    University of Basel, Dept. of Chemistry.
    Bernhardt, Paul V.
    University of Queensland, Dept. of Chemistry, School of Molecular & Microbial Sciences .
    Dunne, Simon J.
    Coordination-mode pH-activated Molecular Switches based on Ruthenium(II) Oligopyridine Complex ArchitectureManuscript (preprint) (Other academic)
    Abstract [en]

    A number of [Ru(tpy)L] complexes (where L is a ligand based on the 6-thien-2-yl-2,2’-bipyridine motif) have been generated to study the ability of this terdentate motif to switch between a N,N,C and a N,N,S binding mode as a function of pH and irradiation. Whilst the parent system 6-thien-2-yl-2,2’-bipyridine (1) displayed facile switching between the orange and purple forms, heavier analogues displayed sluggish switching – most likely resulting from a large moment of inertia about the bond between the S/C-bonded thiophene ring and the chelating bipyridine unit. Prototypic unsymmetrical bimetallic complexes (C7S and C7C) have been generated in order to test if the binding mode of the switching unit can affect the oxidation potential of the remote [Ru(bpy)2(L)] unit. The results of cyclic voltammetry studies suggest that only weak electronic coupling between the metal cores exists, and that the coordination mode (N,N,C or N,N,S) of the thiophene moiety only has a small effect on the oxidation potential of the [Ru(bpy)2(L)] unit.

  • 40.
    Strömberg, Anette
    University of Gothenburg.
    Manipulating and Mimicking Single-Cell Compartments Using Liposome Chemistry and Miniaturized Biomembrane Electropermeabilization2001Doctoral thesis, comprehensive summary (Other academic)
  • 41.
    Waltersson, Johanna
    Mälardalen University, School of Sustainable Development of Society and Technology. Mälardalen University, Department of Biology and Chemical Engineering.
    The metal binding properties of kraft lignin2009Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    There is a strong driving force to increase the competitiveness of the pulping industry by finding new business opportunities. In this context full utilisation of the wood raw material used in conventional pulping mills is of vital importance. One focus area is to increase the utilisation areas of lignin. LignoBoost is a new method to obtain kraft lignin of high purity.

    The aim of the project was to investigate and increase the ability of LignoBoost kraft lignins to bind metals in aqueous solutions.

    The metal binding property of kraft lignins was evaluated using copper (II) ions. The metal binding capacities were 1.76 mg Cu2+/g LignoBoost softwood kraft lignin, 0.96 mg Cu2+/g LignoBoost hardwood kraft lignin and 1.12 mg Cu2+/g condensed softwood kraft lignin. The metal binding capacities of the softwood and hardwood kraft lignins from LignoBoost were lower than expected, when compared to the metal binding capacities of other lignins found in literature. The highest copper binding capacity of a kraft lignin found in literature was almost 50 times greater than that of the LignoBoost softwood kraft lignin.

     

    The Mannich reaction was used to increase the nitrogen content in softwood lignin, and thereby increase its electron-donating capacity. An increase in electron-donating capacity should promote its metal binding capacity.

     

    The Mannich reaction occurs in the vacant ortho position of the phenolic groups of lignin, introducing an aminomethyl group at that position. The only vacant ortho position in the phenol unit for reaction is in the guaicyl unit. Softwood lignin underwent a Mannich reaction, since softwood contains a greater number of guaiacyl units than hardwoods.

     

    A screening of the products from this Mannich reaction on LignoBoost softwood kraft lignin was performed to optimise the reaction conditions. The reaction time, temperature, amount of formaldehyde and dimethylamine were varied. The Mannich products were evaluated by elemental analysis. The conditions giving the highest nitrogen content in the product were used further in a Mannich reaction of condensed softwood kraft lignin. The condensed softwood kraft lignin (7 g) was treated with dimethylamine (0.35 mol) and formaldehyde (0.35 mol) at 80°C for 24 hours.

     

    The metal binding experiment could not be carried out with Mannich-modified condensed softwood kraft lignin since the lignin dissolved in the copper solution.

     

    When introducing nitrogen functionalities into lignin the electron-donating capacity should increase. An increase in donor groups should promote the metal binding capacity of the lignin. A problem that occurred when introducing aminomethyl groups was an increase in solubility of the lignin. Water solubility of the lignin derivative is undesirable in the envisaged utilization area, metal binding in, for example mine deposits, from where contaminated water may be a concentrated source of heavy metals.

  • 42.
    Wolf, Matthew J.
    et al.
    Uppsala Univ, Dept Chem, Angstrom Lab, Uppsala, Sweden.;Univ Bath, Dept Phys, Claverton Down, England..
    Castleton, Christopher
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics. Nottingham Trent Univ, Sch Sci & Technol, Nottingham, England.
    Hermansson, Kersti
    Uppsala Univ, Dept Chem, Angstrom Lab, Uppsala, Sweden..
    Kullgren, Jolla
    Uppsala Univ, Dept Chem, Angstrom Lab, Uppsala, Sweden..
    STM Images of Anionic Defects at CeO2(111)-A Theoretical Perspective2019In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 7, article id 212Article in journal (Refereed)
    Abstract [en]

    We present a theoretically oriented analysis of the appearance and properties of plausible candidates for the anionic defects observed in scanning tunneling microscopy (STM) experiments on CeO2(111). The simulations are based on density functional theory (DFT) and cover oxygen vacancies, fluorine impurities and hydroxyl groups in the surface and sub-surface layers. In the surface layer, all three appear as missing spots in the oxygen sublattice in filled state simulated STM images, but they are distinguishable in empty state images, where surface oxygen vacancies and hydroxyls appear as, respectively, diffuse and sharp bright features at oxygen sites, while fluorine defects appear as triangles of darkened Ce ions. In the sub-surface layer, all three defects present more complex patterns, with different combinations of brightened oxygen ion triangles and/or darkened Ce ion triangles, so we provide image maps to support experimental identification. We also discuss other properties that could be used to distinguish the defects, namely their diffusion rates and distributions.

  • 43.
    Östlund, Lena
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Development of a Multiresidue Method for Analysis of Acidic Pesticides in Cereals with Liquid Chromatography-Tandem Mass Spectrometry2009Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A new method for analysis of acidic herbicides, mostly phenoxy acids and their esters, in cereals with liquid chromatography-tandem quadrupole mass spectrometry (LS-MS/MS) has been developed. Samples were hydrolyzed with sodium hydroxide in order to release covalently bound compounds followed by neutralization and finally extraction with acidified ethyl acetate. The extraction efficiency for both ester formulations and acids were studied. Acceptable results (70-120 %) were obtained for 2,4-D, dichlorprop, MCPA and mecoprop for both esters and acids. However, low recoveries were observed for ester formulations of dicamba, fluroxypyr, fluazifop and haloxyfop, possibly due to the complex structure of the compounds in combination with the matrix and/or incomplete hydrolysis step. The limit of quantification (LOQ) for targeted pesticides was 0.01 mg/kg. The method has been tested in the EU Proficiency Test for cereals with good results.

1 - 43 of 43
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