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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.

     

     

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    FULLTEXT02
  • 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.
    Castleton, Christopher
    et al.
    Uppsala universitet, Sweden.
    Nokbin, Somkiat
    Uppsala universitet, Sweden.
    Hermansson, Kersti
    Uppsala universitet, Sweden.
    Charge transfer and adhesion in Rh/MgO(001)2008In: Proceedings of the 17th international vacuum congress/13th international conference on surface science/international conference on nanoscience and technology / [ed] Johansson LSO; Andersen JN; Gothelid M; Helmersson U; Montelius L; Rubel M; Setina J; Wernersson LE, 2008, p. 082027-Conference paper (Refereed)
    Abstract [en]

    Ab initio density functional calculations are reported for Rh adlayers on MgO(001) at coverages of 1, 1/2 and 1/8 monolayers. It is shown that charge is transferred from oxide surface to the Rh adatoms. The transfer ranges from 0.06 e to 0.27 e, depending upon adsorption site and coverage. In comparison, transfers of 0.08 e from adatom to surface and 0.32 e surface to adatom are found for monolayer coverages of Mg and O, respectively. With the Rh adatoms, significant charge polarization of both Rh and the surface are also seen, but it is never-the-less found that the adhesion energy is linearly related to the charge transfer, with the most stable adsorption site at any particular coverage being the one at which the charge transfer is a maximum.

  • 10.
    Chiu, D T
    et al.
    Univ. of Washington, United States.
    Davidson, M
    Goteborg Univ..
    Strömberg, Anette
    Mälardalen University, School of Innovation, Design and Engineering, Innovation and Product Realisation. Goteborg Univ..
    Ryttsen, F
    Goteborg Univ..
    Orwar, O
    Goteborg Univ..
    Electrical and optical methods for the manipulation and analyses of single cells2001In: CLINICAL DIAGNOSTIC SYSTEMS / [ed] Cohn, G E, Univ Washington, Dept Chem, Seattle, WA 98195 USA.: SPIE-INT SOC OPTICAL ENGINEERING , 2001, p. 1-8Conference paper (Refereed)
    Abstract [en]

    This paper describes the use of focused electric fields and focused optical fields for the high resolution manipulation of single cells. A focused electric field, obtained with the use of ultramicroelectrodes (tip diameter similar to 5 mum), is used to electroporate and electrofuse individual cells selectively and with high spatial resolution. A focused optical field, in the form of an optical tweezer, is used to isolate single organelles from a cell as well as to position liposomes incorporated with receptors and transporters along the cell for the high-resolution sampling and probing of the cellular microenvironment.

  • 11. Chiu, D T
    et al.
    Wilson, C F
    Karlsson, A
    Danielsson, A
    Lundqvist, A
    Strömberg, Anette
    Göteborg University, Göteborg, Sweden.
    Ryttsen, F
    Davidson, M
    Nordholm, S
    Orwar, O
    Zare, R N
    Manipulating the biochemical nanoenvironment around single molecules contained within vesicles1999In: Chemical Physics, ISSN 0301-0104, E-ISSN 1873-4421, Vol. 247, no 1, p. 133-139Article in journal (Refereed)
    Abstract [en]

    A method to study single-molecule reactions confined in a biomimetic container is described. The technique combines rapid vesicle preparation, optical trapping and fluorescence confocal microscopy for performing simultaneous single-vesicle trapping and single-molecule detection experiments. The collisional environment between a single enzyme and substrate inside a vesicle is characterized by a Brownian dynamics Monte Carlo simulation. (C) 1999 Elsevier Science B.V. All rights reserved.

  • 12. Chiu, D T
    et al.
    Wilson, C F
    Ryttsen, F
    Strömberg, Anette
    Göteborg University, Sweden.
    Farre, C
    Karlsson, A
    Nordholm, S
    Gaggar, A
    Modi, B P
    Moscho, A
    Garza-Lopez, R A
    Orwar, O
    Zare, R N
    Chemical transformations in individual ultrasmall biomimetic containers1999In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 283, no 5409, p. 1892-1895Article in journal (Refereed)
    Abstract [en]

    Individual phospholipid vesicles, 1 to 5 micrometers in diameter, containing a single reagent or a complete reaction system, were immobilized with an infrared laser optical trap or by adhesion to modified borosilicate glass surfaces. Chemical transformations were initiated either by electroporation or by electrofusion, in each case through application of a short (10-microsecond), intense (20 to 50 kilovolts per centimeter) electric pulse delivered across ultramicroelectrodes. Product formation was monitored by far-field laser fluorescence microscopy. The ultrasmall characteristic of this reaction volume led to rapid diffusional mixing that permits the study of fast chemical kinetics. This technique is also well suited for the study of reaction dynamics of biological molecules within lipid-enclosed nanoenvironments that mimic cell membranes.

  • 13.
    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.

  • 14.
    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.

  • 15.
    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.

  • 16.
    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.

  • 17.
    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.  

    Download full text (pdf)
    FULLTEXT01
  • 18.
    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.

  • 19.
    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.

  • 20.
    Höglund, Andreas
    et al.
    Uppsala universitet, Sweden.
    Castleton, Christopher
    Uppsala universitet, Sweden.
    Mirbt, Susanne
    Uppsala universitet, Sweden.
    Diffusion mechanism of Zn in InP and GaP from first principles2008In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 77, no 11, p. 113201-Article in journal (Refereed)
    Abstract [en]

    The diffusion mechanism of Zn in GaP and InP has been investigated using first-principles computational methods. It is found that the kickout mechanism is the favored diffusion process under all doping conditions for InP, and under all except n-type conditions for GaP. In n-type GaP the dissociative mechanism is probable. In both p-type GaP and InP, the diffusing species is found to be Zn. The activation energy for the kickout process is 2.49 eV in GaP and 1.60 eV in InP, and therefore unintentional diffusion of Zn should be a larger concern in InP than in GaP. The dependence of the activation energy both on the doping conditions of the material and on the stoichiometry is explained, and found to be in qualitative agreement with the experimentally observed dependencies. The calculated activation energies agree reasonably with experimental data, assuming that the region from which Zn diffuses is p type. Explanations are also found as to why Zn tends to accumulate at pn junctions in InP and to why a relatively low fraction of Zn is found on substitutional sites in InP.

  • 21.
    Höglund, Andreas
    et al.
    Uppsala universitet, Sweden.
    Eriksson, Olle
    Uppsala universitet, Sweden.
    Castleton, Christopher
    Uppsala universitet, Sweden.
    Mirbt, Susanne
    Uppsala universitet, Sweden.
    Increasing the equilibrium solubility of dopants in semiconductor multilayers and alloys2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 100, no 10, p. 105501-Article in journal (Refereed)
    Abstract [en]

    We have theoretically studied the possibility to control the equilibrium solubility of dopants in semiconductor alloys, by strategic tuning of the alloy concentration. From the modeled cases of C-0 in SixGe1-x, Zn- and Cd- in GaxIn1-xP it is seen that under certain conditions the dopant solubility can be orders of magnitude higher in an alloy or multilayer than in either of the elements of the alloy. This is found to be due to the solubility's strong dependence on the lattice constant for size mismatched dopants. The equilibrium doping concentration in alloys or multilayers could therefore be increased significantly. More specifically, Zn- in a GaxIn1-xP multilayer is found to have a maximum solubility for x=0.9, which is 5 orders of magnitude larger than that of pure InP.

  • 22. 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)
  • 23.
    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)
  • 24.
    Karlsson, M
    et al.
    Department of Chemistry, Göteborg University.
    Nolkrantz, K
    Department of Chemistry, Göteborg University.
    Davidson, M J
    Department of Chemistry, Göteborg University.
    Strömberg, Anette
    Department of Chemistry, Göteborg University.
    Ryttsen, F
    Department of Chemistry, Göteborg University.
    Akerman, B
    Department of Chemistry, Göteborg University.
    Orwar, O
    Department of Chemistry, Göteborg University.
    Electroinjection of colloid particles and biopolymers into single unilamellar liposomes and cells for bioanalytical applications2000In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 72, no 23, p. 5857-5862Article in journal (Refereed)
    Abstract [en]

    A combined electroporation and pressure-driven microinjection method for efficient loading of biopolymers and colloidal particles into single-cell-sized unilamellar liposomes was developed. Single liposomes were positioned between a similar to2-mum tip diameter solute-filled glass micropipet, equipped with a Pt electrode, and a 5-mum-diameter carbon fiber electrode. A transient, 1-10 ms, rectangular waveform de voltage pulse (10-40 V/cm) was applied between the electrodes, thus focusing the electric field over the liposome. Dielectric membrane breakdown induced by the applied voltage pulse caused the micropipet tip to enter the liposome and a small volume (typically 50-500 x 10(-15) L) of fluorescein, YOYO-intercalated T7-phage DNA, 100-nm-diameter unilamellar liposomes, or fluorescent latex spheres could be injected into the intraliposomal compartment. We also demonstrate initiation of a chemical intercalation reaction between T2-phage DNA and YOYO-1 by dual injection into a single giant unilamellar liposome. The method was also successfully applied for loading of single cultured cells.

  • 25.
    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.

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    laborationers inverkan på elevers intresse för kemi
  • 26.
    Kostela, Johan
    Uppsala Universitet.
    Electrochemical Behavior of Redox Molecules in Michelles and in a Bicontinous Cubic Phase2003Licentiate thesis, monograph (Other academic)
  • 27.
    Kostela, Johan
    Uppsala universitet, Fysikalisk-kemiska institutionen.
    Electrochemical Studies of Redox Properties and Diffusion in Self-Assembled Systems2004Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis electron transfer reactions and diffusion of redox molecules in three different types of self-aggregated structures are investigated. Electrochemistry was used to investigate the redox potential and diffusion coefficients for redox active molecules with different polarity. The first aggregate system studied was the micellar phase. The role of electrostatic interactions in the stability of an amphiphilic viologen was investigated for differently charged micelles. It was concluded that the electrostatic environment changed the redox potential of the viologen. In differently charged micelles the redox potential was more negative compared to when the viologen was situated in micelles with the same charge.

    The second structure investigated is a very fascinating phase, the bicontinuous cubic phase, with its continuous channels of water and an apolar bilayer. Its domains with different polarity made it possible to solvate both hydrophilic and hydrophobic molecules. An amphiphilic molecule will have its head-group at the interface between the apolar and polar part, and can move lateral within the bilayer. All molecules investigated made contact with and reacted at the surface of the electrode. The diffusion of water bound species diffusing in the water channels was 3-4 times slower than in water. Hydrophobic and amphiphilic molecules were much more hindered, probably because the cubic phase was not defect free.

    The third kind of structure studied was a lamellar system. This phase is built up from planar bilayers that are stacked with a repeating distance and with water in between. A hydrophilic molecule was severely hindered to move in the direction perpendicular to the bilayer plane. Upon addition of the peptide melittin the current increased, due to pore formation in the bilayer.

  • 28.
    Kostela, Johan
    et al.
    Uppsala universitet, Fysikalisk-kemiska institutionen.
    Almgren, Mats
    Electrochemical behaviour of an amphiphilic viologen incorporated in a stacked bilayer systemIn: Journal of Electroanalytical Chemistry, ISSN 0022-0728, E-ISSN 1873-2569Article in journal (Refereed)
  • 29.
    Kostela, Johan
    et al.
    Uppsala universitet, Fysikalisk-kemiska institutionen.
    Almgren, Mats
    Pore formation in a stacked bilayer system induced by the addition of the peptide melittinManuscript (preprint) (Other academic)
  • 30.
    Kostela, Johan
    et al.
    Uppsala Universitet.
    Elmgren, Maja
    Uppsala Universitet.
    Almgren, Mats
    Uppsala Universitet.
    Electrochemical properties and diffusion of a redox active surfactant incorporated in bicontinuous cubic and lamellar phase2005In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 50, no 16-17, p. 3333-Article in journal (Refereed)
    Abstract [en]

    The objective of this study was to investigate the electrochemical behaviour of the divalent redox active surfactant, N-cetyl-N′-methylviologen (CMV), in bicontinuous cubic and lamellar phases. The liquid crystalline phases were prepared from the system glycerolmonooleate (GMO)–water (and brine)–cationic surfactant. A comparison of the phase behaviour of GMO with the monovalent cetyltrimethylammonium bromide (CTAB) and the divalent CMV surfactant showed that the surfactants gave about the same effect at the same surface charge density. The electrochemical measurements were made with a mixture of CTAB and CMV as the surfactant. Cyclic voltammetry was used to study the electrochemistry of CMV incorporated in the cubic and lamellar phases that were spread on a gold electrode. The E0-values in the cubic samples were more negative (−0.55 V versus SCE) than in the lamellar samples (−0.53 V versus SCE). This can be explained by the higher charge density in the lamellar phase. The diffusion coefficients were also measured in the cubic phase. The mass transport is slowed down about fifty times in the cubic phase compared to in the pure electrolyte. The concentration dependence on the diffusion coefficient was also investigated. No electron hopping could be observed, which suggest that diffusional movement of the redox probe is the main source of charge transport. By placing the samples on a conducting glass slide, spectroelectrochemical investigations were performed. In the lamellar phase strong dimerization was detected at high concentration of viologen, but much less in the cubic phase.

  • 31.
    Kostela, Johan
    et al.
    Uppsala universitet, Fysikalisk-kemiska institutionen.
    Elmgren, Maja
    Uppsala universitet, Fysikalisk-kemiska institutionen.
    Almgren, Mats
    Electrochemistry and diffusion of a redox active surfactant in bicontinuous cubic and lamellar phase2005In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 50, no 16-17, p. 3333-3340Article in journal (Refereed)
  • 32.
    Kostela, Johan
    et al.
    Fysikalisk-kemiska institutionen, Uppsala universitet.
    Elmgren, Maja
    Uppsala universitet.
    Hansson, Per
    Uppsala universitet.
    Almgren, Mats
    Uppsala universitet.
    Electrochemical properties of an amphiphilic viologen in differently charged micelles2002In: Journal of Electroanalytical Chemistry, ISSN 0022-0728, E-ISSN 1873-2569, Vol. 536, no 1-2, p. 97-107Article in journal (Refereed)
    Abstract [en]

    The electrochemical properties of N-tetradecyl-N′-methylviologen (TMV) in differently charged micelles were studied with a glassy carbon electrode using electrochemical techniques. The redox potential varied depending on the charge of the surrounding surfactants. When the viologen was situated in cationic micelles the redox potential for the 2+/1+ reaction was more positive than when situated in negatively charged micelles. The non-ionic micelles destabilised the 2+-state most showing the highest redox potentials. From studies of several different cationic micelles it was concluded that the most important parameter for the redox potential was the surface charge density. A calculation based on a simple model confirmed this. Other interactions also influenced the stability of the redox states. Adsorption, desorption and reorganisation of the surfactants at the electrode surface caused capacitive currents. To control the nonfaradaic current, differential pulse voltammetry (DPV) was used in addition to cyclic voltammetry.

  • 33.
    Kostela, Johan
    et al.
    Fysikalisk-kemiska institutionen, Uppsala Universitet.
    Elmgren, Maja
    Uppsala Universitet.
    Kadi, Mari
    Uppsala Universitet.
    Almgren, Mats
    Redox activity and diffusion of hydrophilic, hydrophobic, and amphiphilic redox active molecules in a bicontinuous cubic phase2005In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 109, no 11, p. 5073-Article in journal (Refereed)
  • 34.
    Kullgren, Jolla
    et al.
    Uppsala universitet, Sweden.
    Castleton, Christopher W.M
    Nottingham Trent Univ, Sch Sci & Technol, Nottingham NG11 8NS, England.
    Müller, Carsten
    Uppsala universitet, Sweden.
    Ramo, David Muñoz
    London Ctr Nanotechnol, London WC1E 6BT, England.
    Hermansson, Kersti
    Uppsala universitet, Sweden.
    B3LYP calculations of cerium oxides2010In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 132, no 5, p. 054110-Article in journal (Refereed)
    Abstract [en]

    In this paper we evaluate the performance of density functional theory with the B3LYP functional for calculations on ceria (CeO2) and cerium sesquioxide (Ce2O3). We demonstrate that B3LYP is able to describe CeO2 and Ce2O3 reasonably well. When compared to other functionals, B3LYP performs slightly better than the hybrid functional PBE0 for the electronic properties but slightly worse for the structural properties, although neither performs as well as LDA+U(U = 6 eV) or PBE+U(U = 5 eV). We also make an extensive comparison of atomic basis sets suitable for periodic calculations of these cerium oxides. Here we conclude that there is currently only one type of cerium basis set available in the literature that is able to give a reasonable description of the electronic structure of both CeO2 and Ce2O3. These basis sets are based on a 28 electron effective core potential (ECP) and 30 electrons are attributed to the valence space of cerium. Basis sets based on 46 electron ECPs fail for these materials

  • 35. Kullgren, Jolla
    et al.
    Hermansson, Kersti
    KTH, Teoretisk kemi och biologi.
    Castleton, Christopher
    Nottingham Trent Univ, Sch Sci & Technol, Nottingham NG11 8NS, England.
    Many competing ceria (110) oxygen vacancy structures: From small to large supercells2012In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 137, no 4, p. 044705-Article in journal (Refereed)
    Abstract [en]

    We present periodic "DFT+U" studies of single oxygen vacancies on the CeO2(110) surface using a number of different supercells, finding a range of different local minimum structures for the vacancy and its two accompanying Ce(III) ions. We find three different geometrical structures in combination with a variety of different Ce(III) localization patterns, several of which have not been studied before. The desired trapping of electrons was achieved in a two-stage optimization procedure. We find that the surface oxygen nearest to the vacancy either moves within the plane towards the vacancy, or rises out of the surface into either a symmetric or an unsymmetric bridge structure. Results are shown in seven slab geometry supercells, p(2 x 1), p(2 x 2), p(2 x 3), p(3 x 2), p(2 x 4), p(4 x 2), and p(3 x 3), and indicate that the choice of supercell can affect the results qualitatively and quantitatively. An unsymmetric bridge structure with one nearest and one next-nearest neighbour Ce(III) ion (a combination of localizations not previously found) is the ground state in all (but one) of the supercells studied here, and the relative stability of other structures depends strongly on supercell size. Within any one supercell the formation energies of the different vacancy structures differ by up to 0.5 eV, but the same structure can vary by up to similar to 1 eV between supercells. Furthermore, finite size scaling suggests that the remaining errors (compared to still larger supercells) can also be similar to 1 eV for some vacancy structures.

  • 36.
    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.

  • 37.
    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.

  • 38.
    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.

  • 39.
    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)
  • 40.
    Ledung, Greger
    et al.
    Mälardalen University.
    Göthelid, Emmanuelle
    Mälardalen University. Uppsala University, Sweden.
    Berner, Simon
    University of Zurich, Switzerland.
    Bäckvall, Jan-E.
    Stockholm University, Sweden.
    Puglia, Carla
    Uppsala University, Sweden.
    Oscarsson, Sven
    Mälardalen University, Department of Biology and Chemical Engineering.
    The Performance of a Biomimetic Oxidation Catalyst Immobilised on Gold and Silica Substrates2007In: International Symposium on Relations between Homogeneous and Heterogeneous Catalysis: Abstracts / [ed] Gabor Somorjai, 2007, p. 180-Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    Thiol-functionalized cobalt porphyrins were used as a model system for investigating catalytic activity in homo-geneous and heterogeneous oxidation catalysis. Self-assembled monolayers of thiol-functionalized cobalt porphyrins were prepared on a gold surface and served as heterogeneous catalysts. The immobilization of the molecules prevented the strong inactivation observed for their homogeneous congener. As a result, the turnover number permolecule in heterogeneous catalysis was at least 100 times higher than that of the corresponding homogeneouscatalyst. It is atypical for a heterogenized catalyst to outperform its homogeneous congener. The properties of themolecular layers were characterized on the molecular level by means of X-ray photoelectron spectroscopy (XPS) and scanning probe microscopy (SPM). 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. In order to further investigate the influence of the substrate on the catalytic performance, monolayers of the cobalt porphyrins were grafted onto silica surfaces. The observed catalytic activity together with the surface analytical results are interpreted in relation to the supporting substrate. Preliminary results from this investigation (silicon wafer) show that the catalytic activity is similar to that of gold substrates.

  • 41.
    Lu, Zhansheng
    et al.
    Henan Normal Univ, Coll Phys & Elect Engn, Xinxiang 453007, Peoples R China.
    Yang, Zongxian
    Henan Normal Univ, Coll Phys & Elect Engn, Xinxiang 453007, Peoples R China.
    Hermansson, Kersti
    KTH, Teoretisk kemi och biologi, Sweden.
    Castleton, Christopher W. M.
    Nottingham Trent Univ, Sch Sci & Technol, Nottingham NG11 8NS, England.
    Several different charge transfer and Ce3+ localization scenarios for Rh-CeO2(111)2014In: Journal of Materials Chemistry A, ISSN 2050-7488, E-ISSN 2050-7496, Vol. 2, no 7, p. 2333-2345Article in journal (Refereed)
    Abstract [en]

    We present DFT+U based electronic structure calculations in a p(3 x 3) slab supercell, for low coverages of atomically dispersed Rh interacting with the CeO2(111) surface, comparing Rh as an adatom, and as a dopant substituted into the surface layer. We find that, energetically, a Rh atom approaching a ceria(111) surface with both sparse O and Ce vacancies present strongly prefers to heal the Ce vacancies, but next it prefers to adsorb on a stoichiometric region rather than healing an O vacancy. In the adatom system, Rh is oxidized by electron transfer to a 4f orbital on one Ce ion in the surface layer, which is then nominally converted from Ce4+ -> Ce3+ (i.e. Rh adatoms are single donors). We show that there are a number of different local minima, with Ce3+ localization at 1st, 2nd or 3rd nearest neighbour Ce sites. The second neighbour is the most stable, but all are close in energy. In the Rh-doped system (Rh replaces Ce), Rh is oxidized by charge transfer to neighbouring O atoms, and Rh doping leads to deep acceptor and donor states. Rh is not stable in the O sublattice. Moreover, based on vacancy formation energies, we find that oxygen vacancy formation is strongly enhanced in the vicinity of Rh dopants, but slightly suppressed in the vicinity of Rh adatoms.

  • 42. Lundqvist, J A
    et al.
    Sahlin, F
    Aberg, M A I
    Strömberg, Anette
    Göteborg University, Sweden.
    Eriksson, P S
    Orwar, O
    Altering the biochemical state of individual cultured cells and organelles with ultramicroelectrodes1998In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 95, no 18, p. 10356-10360Article in journal (Other academic)
    Abstract [en]

    We describe an efficient technique for the selective chemical and biological manipulation of the contents of individual cells. This technique is based on the electric-field-induced permeabilization (electroporation) in biological membranes using a low-voltage pulse generator and microelectrodes. A spatially highly focused electric field allows introduction of polar cell-impermeant solutes such as fluorescent dyes, fluorogenic reagents, and DNA into single cells. The high spatial resolution of the technique allows for design of, for example, cellular network constructions in which cells in close contact with each other can be made to possess different biochemical, biophysical, and morphological properties. Fluorescein, and fluo-3 (a calcium-sensitive fluorophore), are electroporated into the soma of cultured single progenitor cells derived from adult rat hippocampus. Fluo-3 also is introduced into individual submicrometer diameter processes of thapsigargin-treated progenitor cells, and a plasmid vector cDNA construct (pRAY 1), expressing the green fluorescent protein, is electroporated into cultured single COS 7 cells, At high electric field strengths, observations of dye-transfer into organelles are proposed.

  • 43.
    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.

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  • 44.
    Mutafela, Richard
    et al.
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM), Sweden.
    Ye, Fei
    KTH Royal institute of technology, Sweden.
    Jani, Yahya
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM), Sweden.
    Dutta, Joydeep
    KTH Royal institute of technology, Sweden.
    Hogland, William
    Linnéuniversitetet, Institutionen för biologi och miljö (BOM).
    Efficient and low-energy mechanochemical extraction of lead from dumped crystal glass waste2021In: Environmental Chemistry Letters, ISSN 1610-3653, E-ISSN 1610-3661, Vol. 19, p. 1879-1885Article in journal (Refereed)
    Abstract [en]

    Glass waste dumps from crystal glass production is an health issue due to the occurrence of antimony, arsenic, cadmium and lead in crystal glass. Recovery of those elements could both decrease pollution and recycle metals in the circular economy. Pyrometallurgy is a potential recovery method, yet limited by high energy consumption. Here we tested a lower-energy alternative in which glass is mechanically activated in a ball mill and leached with nitric acid. Results show that mechanical activation destabilised the glass structure and resulted in 78% lead extraction during leaching at 95 °C. Temperature had the most signifcant efect on extraction, whereas acid concentration, from 0.5 to 3 M, and leaching time, from 0.5 to 12 h, had insignifcant efects. In each experiment, 75% of the fnal extracted amount was achieved within 30 min. The study demonstrates potential for lead extraction from glass waste at lower acid concentration, shorter leaching time and lower temperature, of 95 °C, than traditional pyrometallurgical extraction, typically operating at 1100 °C.

  • 45.
    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)
  • 46.
    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)
  • 47.
    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)

  • 48.
    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.

  • 49.
    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.

  • 50.
    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.

12 1 - 50 of 68
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