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  • 1. Abdel-Rehim, M.
    et al.
    Altun, Zeki
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    New trend in sample preparation: On-line microextraction in packed syringe (MEPS) for LC and GC applications, Part II, Determination of ropivacaine and its metabolites in human plasma samples using MEPS-LC-MS-MS2004In: J. Mass Spectr., 39 (2004) 1488-1493Article in journal (Refereed)
  • 2. Abdel-Rehim, M.
    et al.
    Carlsson, Gunilla
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    Bielenstein, M.
    Arvidsson, T.
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Evaluation of Solid-Phase microextraction (SPME) for Study of the protein Binding in Human Plasma Samples,2000In: J. Chromatogr. Sci., 38 (2000) 458-464Article in journal (Refereed)
  • 3. Abdel-Rehim, M.
    et al.
    Hassan, Z.
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Hassan, M.
    Determination of Busulphan in plasma samples by gas chromatography-mass spectrometry (GC-MS) using on-line derivatization utilizing solid-phase microextraction (SPME)2003In: J. Therapeutic Drug Monitoring, 25 (2003) 400-406Article in journal (Refereed)
  • 4. Abdel-Rehim, M.
    et al.
    Skansen, P.
    Vita, M.
    Hassan, Z.
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Hassan, M.
    Microextraction in packed syringe / liquid chromatography /electrospray tandem mass spectrometry (MEPS/LC/MS/MS) for quantification of olomoucine in human plasma samples2005In: Anal.Chim. Acta., 539 (2005) 35-39Article in journal (Refereed)
  • 5.
    Abdel-Rehim, Mohamed
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. AstraZeneca R&D Sodertalje, Global DMPK, SE-15185 Sodertalje, Sweden.;Stockholm Univ, Dept Analyt Chem, SE-10691 Stockholm, Sweden.;Karlstad Univ, Dept Chem & Biomed Sci, Fac Sci & Technol, SE-65188 Karlstad, Sweden..
    Microextraction by packed sorbent (MEPS): A tutorial2011In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 701, no 2, 119-128 p.Article in journal (Refereed)
    Abstract [en]

    This tutorial provides an overview on a new technique for sample preparation, microextraction by packed sorbent (MEPS). Not only the automation process by MEPS is the advantage but also the much smaller volumes of the samples, solvents and dead volumes in the system. Other significant advantages such as the speed and the simplicity of the sample preparation process are provided. In this tutorial the main concepts of MEPS will be elucidated. Different practical aspects in MEPS are addressed. The factors affecting MEPS performance will be discussed. The application of MEPS in clinical and pre-clinical studies for quantification of drugs and metabolites in blood, plasma and urine will be provided. A comparison between MEPS and other extraction techniques such as SPE, LLE, SPME and SBSE will be discussed. (C) 2011 Elsevier B.V. All rights reserved.

  • 6.
    Abdel-Rehim, Mohamed
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. AstraZeneca R&D Sodertalje, Global DMPK, Sodertalje, Sweden.;Karlstad Univ, Fac Sci & Technol, Dept Chem & Biomed Sci, Karlstad, Sweden..
    On-Line Whole Blood Analysis Using Microextraction by Packed Sorbent and LC-MS-MS2011In: LC GC North America, ISSN 1527-5949, E-ISSN 1939-1889, Vol. 29, no 7, 612-618 p.Article in journal (Refereed)
    Abstract [en]

    Microextraction by packed sorbent (MEPS) is a new technique for sample preparation that can be connected on-line with liquid chromatography (LC) or gas chromatography (GC) systems without any modifications. This article describes the use of MEPS in clinical and preclinical studies to quantify different drugs in whole blood samples. MEPS was used to determine cyclophosphamide in mouse blood from preclinical g studies using 20 mu L of blood samples. The interday accuracies and 0 precisions ranged from 107-109% and from 2.0-7.0%, respectively. The determination of four immunosuppressive drugs in human blood by MEPS and liquid chromatography-mass spectrometry (LC-MS) is described. The method showed a good selectivity and sensitivity. The calibration curves for everolimus, sirolimus, and tacrolimus ranged from 0.5 to 50 ng/mL and for cyclosporine from 3.0 to 1500 ng/mL. Intraday precisions for the studied immunosuppressive drugs were 2.0-11.7% and interday precision ranged from 5.1 to 13.7% (CV).

  • 7.
    Abdel-Rehim, Mohamed
    et al.
    AstraZeneca R&D Södertälje, Södertälje, Sweden.
    Andersson, L.I.
    AstraZeneca R&D Södertälje, Södertälje, Sweden.
    Altun, Zeki
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Microextraction in Packed Syringe Online with Liquid Chromatography-Tandem Mass Spectrometry: Molecularly imprinted polymer as packing material for MEPS in selective extraction of ropivacaine from plasma2006In: Journal of Liquid Chromatography & Related Technologies, ISSN 1082-6076, E-ISSN 1520-572X, Vol. 29, no 12, 1725-1736 p.Article in journal (Refereed)
    Abstract [en]

    The excellent performance of a new sample preparation method, microextraction in packed syringe (MEPS), was recently illustrated by online LC‐MS and GS‐MS assays of local anaesthetics in plasma samples. In the method, approximately 1 mg of solid packing material was inserted into a syringe (100–250 µL) as a plug. Sample preparation took place on the packed bed. The new method was easy to use, fully automated, of low cost, and rapid in comparison with previously used methods. This paper presents the use of molecularly imprinted polymers (MIPs) as packing material for higher extraction selectivity. Development and validation of a method for MIP‐MEPS online with LC‐MS‐MS using ropivacaine in plasma as model compound were investigated. A bupivacaine imprinted polymer was used. The method was validated and the standard curves were evaluated by means of quadratic regression and weighted by inverse of the concentration: 1/x for the calibration range 2–2000 nM. The applied polymer could be used more than 100 times before the syringe was discarded. The extraction recovery was 60%. The results showed high correlation coefficients (R 2 >0.999) for all runs. The accuracy, given as a percentage deviation from the nominal concentration values, ranged from -6% to 3%. The precision, given as the relative standard deviation, at three different concentrations (QC samples) was consistently about 3% to 10%. The limit of quantification was 2 nM.

  • 8. Abdel-Rehim, Mohamed
    et al.
    Dahlgren, Marie
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Quantification of ropivacaine and its major metabolites in human urine samples utilizing microextraction in packed syringe automated with liquid chromatography-tandem mass spectrometry (MEPS-LC-MS-MS)2006In: J. Sep. Sci., 29 (2006) 1658-1661Article in journal (Refereed)
  • 9. Abdel-Rehim, Mohamed
    et al.
    Dahlgren, Marie
    Claude, Saturnin
    Tabacchi, Raphael
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Microextraction in packed syringe (MEPS) utilizing methylcyanopropyl silarylene as coating polymer for extraction of drugs in biological samples,2006In: J. Liq. Chromatogr. & Relat. Technol., 29 (2006) No. 17, 2537-2544Article in journal (Refereed)
  • 10. Almgren, M
    et al.
    Alsins, J
    Mukhtar, E
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    Diffusion-Controlled Fluorescence Quenching in Micelles1989In: Reactions in Compartmentalized Liquids; Knoche W and Shomacker R (eds), Springer-Verlag, Berlin Heidelberg (1989), 61-68, 1989Chapter in book (Refereed)
  • 11. Almgren, M.
    et al.
    Alsins, J.
    Mukhtar, E.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    Fluorescence Quenching Dynamics in Rodlike Micelles1988In: J. Phys. Chem., 1988, 92, 4479-4483Article in journal (Refereed)
  • 12. Almgren, M.
    et al.
    Alsins, J.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    Fluorescence Decay Studies of Structures and Dynamics in Ionic Micellar Solutions1988In: Ordering and Organization in Ionic Solutions, World Scientific Publishing Co Ltd, Singapore, 1988, 225-232, 1988Chapter in book (Refereed)
  • 13. Almgren, M
    et al.
    Alsins, J
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    Mukhtar, E
    The micellar sphere-to-rod transition in CTAC-NaClO3. A fluorescence quenching study1988In: Progr. Colloid Polym. Sci., 1988, 76, 68-74Article in journal (Refereed)
  • 14. Almgren, M.
    et al.
    Hansson, P.
    Mukhtar, E.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    Aggregation of Alkyltrimethylammonium Surfactants in Aqueous Poly(styrenesulfonate) Solutions1992In: Langmuir, 1992, 8, 2405-2412Article in journal (Refereed)
  • 15. Almgren, M.
    et al.
    Löfroth, J-E
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    Fluorescence Decay Kinetics in Monodisperse Confinements with Exchange of Probes and Quenchers1986In: J. Phys. Chem., 1986, 90, 4431-4437Article in journal (Refereed)
  • 16. Almgren, M.
    et al.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    Lindblad, C.
    Li, P.
    Stilbs, P.
    Bahadur, P.
    Aggregation of Poly(ethyelene oxide)-Poly(propylene oxide)-Poly(ethylene oxide) Triblock Copolymers in the Presence of Sodium Dodecyl Sulfate in Aqueous Solution1991In: J. Phys. Chem., 1991, 95, 5677-5684Article in journal (Refereed)
  • 17. Almgren, M
    et al.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    Swarup, S
    Löfroth, J-E
    Structure and Transport in the Microemulsion Phase of the System Triton X-100-Toluene-Water1986In: Langmuir, 1986, 2, 432-438Article in journal (Refereed)
  • 18.
    Alriksson, Björn
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Ethanol from lignocellulose: Alkali detoxification of dilute-acid spruce hydrolysates2006Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Detoxification of dilute-acid lignocellulose hydrolysates by treatment with Ca(OH)2 (overliming) efficiently improves the production of fuel ethanol, but is associated with drawbacks like sugar degradation and CaSO4 precipitation. In factorial designed experiments, in which pH and temperature were varied, dilute-acid spruce hydrolysates were treated with Ca(OH)2, NH4OH or NaOH. The concentrations of sugars and inhibitory compounds were measured before and after the treatments. The fermentability was examined using the yeast Saccharomyces cerevisiae and compared with reference fermentations of synthetic medium without inhibitors. The treatment conditions were evaluated by comparing the balanced ethanol yield, which takes both the degradation of sugars and the ethanol production into account. Treatment conditions resulting in excellent fermentability and minimal sugar degradation were possible to find regardless of whether Ca(OH)2, NH4OH or NaOH was used. Balanced ethanol yields higher than those of the reference fermentations were achieved for hydrolysates treated with all three types of alkali. As expected, treatment with Ca(OH)2 gave rise to precipitated CaSO4. The NH4OH treatments gave rise to a brownish precipitate but the amounts of precipitate formed were relatively small. No precipitate was observed in treatments with NaOH. The possibility that the ammonium ions from the NH4OH treatments gave a positive effect as an extra source of nitrogen during the fermentations was excluded after experiments in which NH4Cl was added to the medium. The findings presented can be used to improve the effectiveness of alkali detoxification of lignocellulose hydrolysates and to minimize problems with sugar degradation and formation of precipitates.

  • 19.
    Alriksson, Björn
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Ethanol from lignocellulose: Management of by-products of hydrolysis2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Fuel ethanol can be produced from lignocellulosic materials, such as residues from agriculture and forestry. The polysaccharides of lignocellulose are converted to sugars by hydrolysis and the sugars can then be fermented to ethanol using microorganisms. However, during hydrolysis a wide range of by-products are also generated. By-product formation can affect ethanol yield and productivity. Management of by-products of hydrolysis is therefore important in the development of commercially viable production of cellulosic ethanol.

    Detoxification of inhibitory dilute-acid lignocellulose hydrolysates by treatment with Ca(OH)2 (overliming) efficiently improves the fermentability, but is associated with drawbacks like sugar degradation and CaSO4 precipitation. In factorial designed experiments, in which pH and temperature were varied, dilute-acid spruce hydrolysates were treated with Ca(OH)2, NH4OH or NaOH. The concentrations of sugars and inhibitory compounds were measured before and after the treatments. The fermentability was examined using the yeast Saccharomyces cerevisiae and compared with reference fermentations of synthetic medium without inhibitors. The treatment conditions were evaluated by comparing the balanced ethanol yield, which takes both the degradation of sugars and the ethanol production into account. Treatment conditions resulting in excellent fermentability and minimal sugar degradation were possible to find regardless of whether Ca(OH)2, NH4OH or NaOH was used. Balanced ethanol yields higher than those of the reference fermentations were achieved for hydrolysates treated with all three types of alkali. As expected, treatment with Ca(OH)2 gave rise to precipitated CaSO4. The NH4OH treatments gave rise to a brownish precipitate but the amounts of precipitate formed were relatively small. No precipitate was observed in treatments with NaOH. The findings presented can be used to improve the effectiveness of alkali detoxification of lignocellulose hydrolysates and to minimize problems with sugar degradation and formation of precipitates.

    Overexpression of different S. cerevisiae genes was investigated with the aim to engineer a biocatalyst with increased inhibitor tolerance. Overexpression of YAP1, a gene encoding a transcription factor, conveyed increased resistance to lignocellulose-derived inhibitors as well as to a dilute-acid hydrolysate of spruce.

    Recombinant Aspergillus niger expressing the Hypocrea jecorina endoglucanase Cel7B was cultivated on spent lignocellulose hydrolysate (stillage). The fungus simultaneously removed inhibitors present in the stillage and produced higher amounts of endoglucanase than when it was grown in a standard medium with comparable monosaccharide content. The concept can be applied for on-site production of enzymes in a cellulose-to-ethanol process and facilitate recycling of the stillage stream.

  • 20.
    Alriksson, Björn
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Rose, Shaunita, H
    Department of Microbiology, University of Stellenbosch, South Africa.
    van Zyl, Wilhelm, H
    Department of Microbiology, University of Stellenbosch, South Africa.
    Sjöde, Anders
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Nilvebrant, Nils-Olof
    STFI-Packforsk AB, Stockholm, Sweden.
    Jönsson, Leif J.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Cellulase Production from Spent Lignocellulose Hydrolysates with Recombinant Aspergillus niger.2009In: Applied and Environmental Microbiology, ISSN 0099-2240, E-ISSN 1098-5336, Vol. 75, no 8, 2366-2374 p.Article in journal (Refereed)
  • 21.
    Alriksson, Björn
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Sárvári Horváth, Ilona
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Jönsson, Leif J.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Overexpression of Saccharomyces cerevisiae transcription factor and multidrug resistance genes conveys enhanced resistance to lignocellulose-derived fermentation inhibitors.2010In: Process Biochemistry, ISSN 1359-5113, E-ISSN 1873-3298, Vol. 45, no 2, 264-271 p.Article in journal (Refereed)
  • 22. Altun, Z.
    et al.
    Andersson, L.I.
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Abdel-Rehim, M.
    Some factors affecting the performance of microextraction in packed syringe (MEPS)2008In: submitted to Analyt. Chim. ActaArticle in journal (Refereed)
  • 23.
    Altun, Zeki
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    New Techniques for Sample Preparation in Analytical Chemistry: Microextraction in Packed Syringe (MEPS) and Methacrylate Based Monolithic Pipette Tips2008Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Sample preparation is often a bottleneck in systems for chemical analysis. The aim of this work was to investigate and develop new techniques to address some of the shortcomings of current sample preparation methods. The goal has been to provide full automation, on-line coupling to detection systems, short sample preparation times and high-throughput.

    In this work a new technique for sample preparation that can be connected on-line to liquid chromatography (LC) and gas chromatography (GC) has been developed. Microextraction in packed syringe (MEPS) is a new solid-phase extraction (SPE) technique that is miniaturized and can be fully automated. In MEPS approximately 1 mg of sorbent material is inserted into a gas tight syringe (100-250 μL) as a plug. Sample preparation takes place on the packed bed. Evaluation of the technique was done by the determination of local anaesthetics in human plasma samples using MEPS on-line with LC and tandem mass spectrometry (MS-MS). MEPS connected to an autosampler was fully automated and clean-up of the samples took about one minute. In addition, in the case of plasma samples the same plug of sorbent could be used for about 100 extractions before it was discarded.

    A further aim of this work was to increase sample preparation throughput. To do that disposable pipette tips were packed with a plug of porous polymer monoliths as sample adsorbent and were then used in connection with 96-well plates and LC-MS-MS. The evaluation of the methods was done by the analysis of local anaesthetics lidocaine and ropivacaine, and anti-cancer drug roscovitine in plasma samples. When roscovitine and lidocaine in human plasma and water samples were used as model substances, a 96-plate was handled in about two minutes. Further, disposable pipette tips may be produced at low cost and because they are used only once, carry-over is eliminated.

  • 24. Altun, Zeki
    et al.
    Abdel-Rehim, M.
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    New trends in sample preparation: On-line microextraction in packed syringe (MEPS) for LC and GC applications. Part III Determination and validation of local anaesthetics in human plasma samples using a cation-exchange sorbent and MEPS-LC-MS-MS2004In: J. Chromatogr. B, 813 (2004) 129-135Article in journal (Refereed)
  • 25.
    Altun, Zeki
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Andersson, Lars I.
    AstraZeneca R&D Södertälje, DMPK & BAC, Södertälje, Sweden.
    Blomberg, Lars G.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Abdel-Rehim, Mohamed
    Karlstad University, Division for Business and Economics.
    Some Factors Affecting the Performance of Microextraction in Packed Syringe (MEPS)Manuscript (Other academic)
  • 26. Altun, Zeki
    et al.
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Use of carbon dioxide and ammonia as nebulizer gases in mass spectrometry2002In: Rapid Comm. Mass Spectrometry, 16 (2002) 738-739Article in journal (Refereed)
  • 27. Altun, Zeki
    et al.
    Hjelmström, Anette
    Abdel-Rehim, Mohamed
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Surface Modified Polypropylene Pipette Tips Packed with a Monolithic Plug of Adsorbent for High Throughput Sample Preparation2007In: J. Sep. Sci., 30 (2007) 1964-1972Article in journal (Refereed)
  • 28. Altun, Zeki
    et al.
    Hjelmström, Anette
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Abdel-Rehim, Mohamed
    Evaluation of monolithic packed 96-tips for solid-phase extraction of local anesthetics from human plasma for quantitation by liquid chromatography tandem mass spectrometry2008In: J. Liq. Chromatogr. & Relat. Technol , 31 (2008) 743-751Article in journal (Refereed)
  • 29. Altun, Zeki
    et al.
    Jagerdeo, E.
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Abdel-Rehim, M.
    Drug screening using microextraction in packed syringe (MEPS) / LC-MS utilizing monolithic-based sorbent material,2006In: Journal of Liquid Chromatography and Related Technologies, 29 (2006) 829-839Article in journal (Refereed)
  • 30. Andersson, Magnus
    et al.
    Lu, B.
    Abdel-Rehim, M.
    Blomberg, S.
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Capillary electrophoresis methods for the separation of the basic compound lidocaine and its metabolites2004In: Rapid Commun. Mass Spectr., 18 (2004) 2612-2618Article in journal (Refereed)
  • 31. Andersson, Magnus
    et al.
    Wan, H.
    Abdel-Rehim, M.
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Characterization of Lidocaine and its Metabolites in Human Plasma using Capillary Electrophoresis,1999In: J. Microcol. Sep., 11, (1999) 620-626Article in journal (Refereed)
  • 32. Andersson, M.B.O.
    et al.
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Electric field-assisted micro-packed HPLC,2001In: J. Sep. Sci. 24 (2001) 304-308Article in journal (Refereed)
  • 33. Andersson,, M.B.O.
    et al.
    King, J.W.
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Synthesis of fatty alcohol mixtures from oleochemicals in supercritical fluids,2000In: Green Chemistry, (2000) 230-234Article in journal (Refereed)
  • 34.
    Anselmo, Ana Sofia
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering. Karlstad University, Faculty of Technology and Science, Materials Science.
    Dzwilewski, Andrzej
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Rysz, Jakub
    M. Smoluchowski Insitute of Physics, Jagiellonian University, Reymonta 4, Krakow 30–059, Poland.
    Bernasik, Andrzej
    Faculty of Physics and Applied Computer Science, AGH-University of Science and Technology, Al. Mickiewicza 30, Krakow 30–059, Poland.
    Budkowski, Andrzej
    M. Smoluchowski Insitute of Physics, Jagiellonian University, Reymonta 4, Krakow 30–059, Poland.
    Andersson, Mats R.
    Department of Chemical and Biological Engineering, Chalmers University of Technology.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Svensson, Krister
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Moons, Ellen
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering. Karlstad University, Faculty of Technology and Science, Materials Science.
    Characterisation of vertical phase separation in polymer: fullerene blend films for photovoltaics by dSIMS and NEXAFS2011In: E-MRS 2011 Spring Meeting: Bilateral Energy Conference, Malden, MA: John Wiley & Sons, 2011, 62-63 p.Conference paper (Refereed)
    Abstract [en]

    Morphological control and characterization of blend films is key in the development of viable polymer solar cells. Spontaneous formation of vertical compositional gradients during solution processing has been shown for polyfluorene:PCBM blends and rationalized with thermodynamic and kinetic models of nucleation and spinodal decomposition.[1, 2] The extent of vertical stratification is affected by polymer side-chain modification aimed at controlling polymer:fullerene miscibility.[3] Here we present high-resolution film morphology results for several polymer:fullerene systems as obtained from near-edge X-ray fine structure spectroscopy (NEXAFS) in partial and in total electron yield modes. Blend films were found to be polymer- enriched at the surface. Dynamic secondary ion mass spectrometry (dSIMS) and NEXAFS give compositional information at different depths, resulting in a more complete picture of the film morphology.

     

  • 35.
    Anselmo, Ana Sofia
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering. Karlstad University, Faculty of Technology and Science, Materials Science.
    Dzwilewski, Andrzej
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Rysz, Jakub
    M. Smoluchowski Insitute of Physics, Jagiellonian University, Reymonta 4, Krakow 30–059, Poland.
    Budkowski, Andrzej
    M. Smoluchowski Insitute of Physics, Jagiellonian University, Reymonta 4, Krakow 30–059, Poland.
    Svensson, Krister
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Moons, Ellen
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering. Karlstad University, Faculty of Technology and Science, Materials Science.
    Polymer solar cells: Visualizing vertical phase separation in solution-processed films of polymer fullerene blends2012In: Proceedings of the 5th International Symposium Technologies for Polymer Electronics - TPE 12 / [ed] Hans-Klaus Roth, Klaus Heinemann, Ilmenau, Germany: Universitätsverlag Ilmenau , 2012, 125-128 p.Conference paper (Refereed)
  • 36.
    Anselmo, Ana Sofia
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering. Karlstad University, Faculty of Technology and Science, Materials Science.
    Dzwilewski, Andrzej
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Wang, Ergang
    Department of Chemical and Biological Engineering, Chalmers University of Technology.
    Andersson, Mats R.
    Department of Chemical and Biological Engineering, Chalmers University of Technology.
    Hörmann, Ulrich
    Institute of Physics, Augsburg University.
    Opitz, Andreas
    Institute of Physics, Augsburg University.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Svensson, Krister
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Moons, Ellen
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Surface Organization in Thin-Films of Conjugated Polymers for Organic Photovoltaics2011Conference paper (Other academic)
  • 37.
    Anselmo, Ana Sofia
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering. Karlstad University, Faculty of Technology and Science, Materials Science.
    Dzwilewski, Andrzej
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Wang, Ergang
    Chalmers University of Technology.
    Andersson, Mats R.
    Chalmers University of Technology.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Svensson, Krister
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Moons, Ellen
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering. Karlstad University, Faculty of Technology and Science, Materials Science.
    Molecular orientation and composition at the surface of APFO3:PCBM blend films2012In: Hybrid and Organics Photovoltaics Conference: Uppsala, Sweden, 2012 / [ed] Anders Hagfeldt, SEFIN, Castelló (Spain), 2012, 278- p.Conference paper (Refereed)
  • 38.
    Anselmo, Ana Sofia
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering. Karlstad University, Faculty of Technology and Science, Materials Science.
    Lindgren, Lars
    Department of Chemical and Biological Engineering, Chalmers University of Technology.
    Rysz, Jakub
    Institute of Physics, Jagiellonian University, Poland.
    Bernasik, Andrzej
    Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Poland.
    Budkowski, Andrzej
    Institute of Physics, Jagiellonian University, Poland.
    Andersson, Mats R.
    Department of Chemical and Biological Engineering, Chalmers University of Technology.
    Svensson, Krister
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Moons, Ellen
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering. Karlstad University, Faculty of Technology and Science, Materials Science.
    Tuning the Vertical Phase Separation in Polyfluorene:Fullerene Blend Films by Polymer Functionalization2011In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 23, no 9, 2295-2302 p.Article in journal (Refereed)
    Abstract [en]

    Achieving control over the nanomorphology of blend films of the fullerene derivative [6,6]-phenyl C61-butyric acid methyl ester, PCBM, with light-absorbing conjugated polymers is an important challenge in the development of efficient solution-processed photovoltaics. Here, three new polyfluorene copolymers are presented, tailored for enhanced miscibility with the fullerene through the introduction of polymer segments with modified side chains, which enhance the polymer’s polar character. The composition of the spincoated polymer:PCBM films is analyzed with dynamic secondary ion mass spectrometry (dSIMS). The dSIMS depth profiles demonstrate compositional variations perpendicular to the surface plane, as a result of vertical phase separation, directed by the substrate. These variations propagate to a higher degree through the film for the polymers with a larger fraction of modified side chains. The surface composition of the films is studied by Near-edge X-ray absorption fine structure spectroscopy (NEXAFS). Quantitative analysis of the NEXAFS spectra through a linear combination fit with the spectra of the pure components yields the surface composition. The resulting blend ratios reveal polymer-enrichment of the film surface for all three blends, which also becomes stronger as the polar character of the polymer increases. Comparison of the NEXAFS spectra collected with two different sampling depths shows that the vertical composition gradient builds up already in the first nanometers underneath the surface of the films. The results obtained with this new series of polymers shed light on the onset of formation of lamellar structures in thin polymer:PCBM films prepared from highly volatile solvents

  • 39.
    Anselmo, Ana Sofia
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering. Karlstad University, Faculty of Technology and Science, Materials Science.
    Lindgren, Lars
    Department of Chemical and Biological Engineering, Chalmers University of Technology.
    Svensson, Krister
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Hörmann, Ulrich
    Institute of Physics, University of Augsburg.
    Brütting, Wolfgang
    Institute of Physics, University of Augsburg.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Andersson, Mats R.
    Department of Chemical and Biological Engineering, Chalmers University of Technology.
    Opitz, Andreas
    Institute of Physics, Humboldt University Berlin.
    Moons, Ellen
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Polyfluorene copolymers with functionalized side chains: Opto-electronic properties and solar cell performance2012Manuscript (preprint) (Other academic)
  • 40.
    Anselmo, Ana Sofia
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Moons, Ellen
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    Svensson, Krister
    Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Morphology of Thin-Films of Polyfluorene: Fullerene Blends2008In: 1st Portuguese Young Chemists Meeting, PYCheM: Abstracts, 2008, 36-36 p.Conference paper (Refereed)
  • 41.
    Ashri, Nadia Y.
    et al.
    Najd Consulting Hosp, Riyadh, Saudi Arabia..
    Abdel-Rehim, Mohamed
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. AstraZeneca R&D Sodertalje, Clin Pharmacol, SE-15185 Sodertalje, Sweden.;AstraZeneca R&D Sodertalje, DMPK, SE-15185 Sodertalje, Sweden.;Karlstad Univ, Dept Chem & Biomed Sci, SE-65188 Karlstad, Sweden.;Stockholm Univ, Dept Analyt Chem, SE-10691 Stockholm, Sweden..
    Sample treatment based on extraction techniques in biological matrices2011In: Bioanalysis, ISSN 1757-6180, E-ISSN 1757-6199, Vol. 3, no 17, 2003-2018 p.Article, review/survey (Refereed)
    Abstract [en]

    The importance of sample preparation methods as the first stage in bioanalysis is described. In this article, the sample preparation concept and strategies will be discussed, along with the requirements for good sample preparation. The most widely used sample preparation methods in the pharmaceutical industry are presented; for example, the need for same-day rotation of results from large numbers of biological samples in pharmaceutical industry makes high throughput bioanalysis more essential. In this article, high-throughput sample preparation techniques are presented; examples are given of the extraction and concentration of analytes from biological matrices, including protein precipitation, solid-phase extraction, liquid-liquid extraction and microextraction-related techniques. Finally, the potential role of selective extraction methods, including molecular imprinted phases, is considered.

  • 42. Babcock, G.T.
    et al.
    Floris, R.
    Nilsson, Thomas
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Pressler, M. A.
    Varotsis, C.
    Vollenbroek, E.
    Dioxygen activation in enzymic systems and in inorganic models1996In: Inorg. Chim. Acta, 243 , 345-353Article in journal (Refereed)
  • 43.
    Bassyouni, Fatma A.
    et al.
    Natl Res Ctr, Ctr Excellence Adv Sci, Dept Chem Nat & Microbial Prod & Pharmaceut Res, Cairo, Egypt..
    Abu-Bakr, Sherifa M.
    Natl Res Ctr, Dept Chem Nat & Microbial Prod, Cairo, Egypt..
    Rehim, Mohamed Abdel
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. AstraZeneca, DMPK, R&D, S-15185 Sodertalje, Sweden..
    Evolution of microwave irradiation and its application in green chemistry and biosciences2012In: Research on chemical intermediates (Print), ISSN 0922-6168, E-ISSN 1568-5675, Vol. 38, no 2, 283-322 p.Article, review/survey (Refereed)
    Abstract [en]

    Microwave-assisted organic reactions have been applied as an effective technique in organic synthesis. Microwave irradiation often leads to shorter reaction times, increased yields, easier workup, matches with green chemistry protocols, and can enhance the region and stereo selectivity of reactions. In fact, the high usefulness of microwave-assisted synthesis encouraged us to increase the efficiency of several organic transformations and synthesis. High-speed microwave-assisted chemistry has attracted a considerable amount of attention in recent years and has been applied successfully in various fields of synthetic organic chemistry, proteins, peptides, drug discovery, and green chemistry. The various roles of microwave-assisted organic chemistry in green and sustainable chemistry are discussed, beginning with the strategies, technologies, and methods that were employed routinely at the time of the first reports of microwave applications. Microwave processing has several advantages over conventional sintering/heating, such as the reduction in cycle time, energy efficiency, eco-friendliness, and providing finer microstructures, leading to improved mechanical properties. Herein, we also describe the evolution of the microwave and some early applications of microwave assistance in the biomolecular sciences and treatment of solid malignant tumors.

  • 44.
    Bergqvist, Anna
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Models of chemical bonding: Representations Used in School Textbooks and by Teachers and their Relation to Students´Difficulties in Understanding.2012Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis focuses on how school textbooks and teachers present models of chemical bonding in upper secondary schools in Sweden. In science, as well as in science education, models play a central role, but research has shown that they often are difficult for students to understand. In science education, models are presented to students mainly through textbooks and teachers, and textbooks influence teachers’ teaching. The aim of this thesis was to investigate how textbooks and teachers present models of chemical bonding with respect to students’ difficulties in understanding.

    To analyze representations of models, an analytical framework based on research reports of students’ difficulties in understanding related to models in general and chemical bonding in particular was developed. The chapters of chemical bonding in five chemistry textbooks were analyzed. Further, ten Chemistry teachers’ lesson plans about chemical bonding and semi-structured interviews with the teachers concerning their teaching were analyzed.

    This analysis concerned teachers pedagogical content knowledge (PCK) of teaching chemical bonding, with focus on knowledge of students’ difficulties in understanding and teaching strategies that take these difficulties into account. The results show that the teachers could specify examples of students’ learning difficulties, but the teaching strategies to promote the students’ understanding were limited. This indicates a deficient interaction between knowledge of difficulties in understanding and teaching strategies, two essential components of teachers’ PCK. Further, the models of chemical bonding represented in the textbooks and by the teachers might cause students’ difficulties in understanding. This indicates a gap between research of students’ difficulties in understanding and teaching practices as well as textbooks’ development. Further, the teachers’ representations of models were strongly influenced by the textbooks. Implications for textbooks’ authors, pre-service as well as in-service teachers are addressed.

     

     

     

  • 45.
    Bergqvist, Anna
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Drechsler, Michal
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    De Jong, Onno
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Chang Rundgren, Shu-Nu
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Swedish upper secondary teachers’ pedagogical content knowledge to teach chemical bondingIn: Research in science education, ISSN 0157-244X, E-ISSN 1573-1898Article in journal (Other academic)
    Abstract [en]

    In the last two decades, researchers have shown a growing interest in science teachers’ knowledge. The present study focuses on chemistry teachers’ knowledge of teaching one of the most important topics at upper secondary school chemistry, chemical bonding, dominated by the use of models. Models are important to understand science, however, research has shown that the use of models in science education also can cause students’ learning difficulties, and that chemical bonding is a topic that students find difficult. The aim of this study is to investigate the teachers’ pedagogical content knowledge (PCK) of teaching chemical bonding in order to promote students’ understanding with a focus on teachers’ knowledge of students’ learning difficulties and teaching strategies to meet these difficulties. In this study, ten Chemistry teachers’ lesson plans about chemical bonding and semi-structured interviews with the teachers concerning their teaching were analyzed. The representations of models of chemical bonding used by the teachers were compared to the representations used in the textbooks. Our results showed that teachers could specify examples of students’ learning difficulties, but the teaching strategies were limited in order to promote the students’ understanding. These results indicate a deficient interaction between knowledge of learning difficulties and teaching strategies, two essential components of teachers’ PCK. Further, the teachers were not aware of in what way the representations of models might influence the students’ understanding negatively, indicating a gap between research of students’ learning difficulties regarding chemical bonding and teaching practices. Furthermore, the teachers’ representations of models of chemical bonding were strongly influenced by the textbooks. Implications for pre-service as well as in-service teachers are addressed.

  • 46. Bhaskar Dutt, G.
    et al.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences. Karlstad University, Faculty of Technology and Science, Materials Science.
    De Schryver, FC
    Are Aqueous Sodium Dodecyl Sulfate Micelles in the Presence of Added Salt Polydisperse? A Time-Resolved Fluorescence Quenching Study with Global Analysis1997In: Langmuir, 1997, 13, 1957-1963Article in journal (Refereed)
  • 47.
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Models in chemistry education - A study of teaching and learning acids and bases in Swedish upper secondary schools2007Doctoral thesis, monograph (Other academic)
  • 48.
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Silicone stationary phases for gas chromatography,2001In: LC/GC Europe, 14 (2001) 106-112Article in journal (Refereed)
  • 49.
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Textbooks, teachers, and students understanding of models used to explain acid-base reactions2005Licentiate thesis, monograph (Other academic)
  • 50.
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Two new techniques for sample preparation in bioanalysis: Microextraction in packed sorbent (MEPS) and use of a bonded monolith as sorbent for sample preparation in polypropylene tips for 96-well plates2009In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 393, no 3, 797-807 p.Article in journal (Refereed)
1234567 1 - 50 of 411
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