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  • 101.
    Blomberg, Lars G
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Said, Rana
    Hassan, Moustapha
    Hassan, Zuzan
    Abdel-Rehim, Mohamed
    Rapid and sensitive method for determination of cyclophosphamide in patients plasma samples utilizing microextraction by packed sorbent online with liquid chromatography-tandem mass spectrometry (MEPS-LC-MS/MS)2008In: J. Liq. Chromatogr. & Relat. Technol., acceptedArticle in journal (Refereed)
  • 102.
    Blomberg, Lars G
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Vita, M.
    Abdel-Rehim, M.
    Nilsson, C.
    Hassan, Z.
    Skansen, P.
    Wan, H.
    Meurling, L.
    Hassan, M.
    Stability, pKa and plasma protein binding of roscovitine2005In: J. Chromatogr. B, 821 (2005) 75-80Article in journal (Refereed)
  • 103.
    Blomberg, Lars G
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Vita, M.
    Skansen, P.
    Hassan, M.
    Abdel-Rehim, M.
    Development and validation of a liquid chromatography and mass spectrometry method for determination of roscovitine in plasma and urine samples utilizing on-line sample preparation2005In: J. Chromatogr. B, 817 (2005) 303-307Article in journal (Refereed)
  • 104.
    Blomberg, Lars G
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Wan, H.
    Determination of enantiomeric excess by capillary electrophoresis,2000In: Electrophoresis, 21, (2000) 1940-1952Article in journal (Refereed)
  • 105.
    Blomberg, Lars G
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Öhman, Marcus
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Separation of Fatty Acid Isomers by Capillary Electrophoresis2002Licentiate thesis, monograph (Other academic)
  • 106. Bohlin, C.
    et al.
    Andersson, P.-O.
    Lundquist, K.
    Jönsson, Leif J
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre.
    Differences in stereo-preference in the oxidative degradation of diastereomers of the lignin model compound 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol with enzymic and non-enzymic oxidants2007In: J. Mol. Catal. B Enzym. (2007) 45, 21-26Article in journal (Refereed)
  • 107. Bohlin, C.
    et al.
    Jönsson, Leif J
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre.
    Roth, R.
    van Zyl, W.H.
    Heterologous expression of Trametes versicolor laccase in Pichia pastoris and Aspergillus niger2006In: Appl. Biochem. Biotechnol. (2006) 129-132, 195-214Article in journal (Refereed)
  • 108. Bohlin, C.
    et al.
    Persson, P.
    Gorton, L.
    Lundquist, K.
    Jönsson, Leif J
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre.
    Product profiles in enzymic and non-enzymic oxidations of the lignin model compound erythro-1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol2005In: J. Mol. Catal. B Enzym. (2005) 35, 100-107Article in journal (Refereed)
  • 109.
    Bohlin, Christina
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Jönsson, Leif J
    Karlstad University, Faculty of Technology and Science, Paper Surface Centre.
    Lundquist, K
    Oxidation of the erythro and threo forms of the phenolic lignin model compound 1-(4-hydroxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol by laccases and model oxidants2009In: Bioorganic chemistry (Print), ISSN 0045-2068, Vol. 37, no 5, p. 143-148Article in journal (Refereed)
    Abstract [en]

    Mixtures of equal amounts of the erythro and threo forms of the phenolic arylglycerol β-aryl ether 1-(4-hydroxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol were oxidized (i) with laccases from Trametes versicolor, Agaricus bisporus, Myceliophthora thermophila and Rhus vernicifera, (ii) with laccase-mediator systems consisting of T. versicolor laccase and ABTS or HBT, and (iii) with various model oxidants including cerium(IV) ammonium nitrate (CAN), lignin peroxidase, Fenton’s reagent, and lead(IV) tetraacetate (LTA). All the laccases exhibited a similar preferential degradation of the threo form. The mediator ABTS counteracted the threo preference of laccase, but the mediator HBT did not affect it. The outer-sphere model oxidants CAN and lignin peroxidase showed a preferential degradation of the threo form. LTA and Fenton’s reagent did not exhibit any stereo-preference. The results suggest that laccases of different origin, primary structure, and redox potential behave as typical outer-sphere oxidants in their interaction with the diastereomers of the arylglycerol β-aryl ether

  • 110.
    Bohlin, Christina
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Lundquist, Knut
    Forest Products and Chemical Engineering, Department of Chemical and Biological Engineering, Chalmers Univeristy of Technology.
    Jönsson, Leif J.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Diastereomer selectivity in the degradation of a lignin model compound of the arylglycerol β-aryl ether type by white-rot fungi2008In: Enzyme and microbial technology, ISSN 0141-0229, E-ISSN 1879-0909, Vol. 43, no 2, p. 199-204Article in journal (Refereed)
  • 111.
    Bohlin, Christina
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Lundquist, Knut
    Forest Products and Chemical Engineering, Department of Chemical and Biological Engineering, Chalmers University of Technology.
    Jönsson, Leif J.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Oxidation of the erythro and threo forms of the phenolic lignin model compound 1-(4-hydroxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol by laccases and model oxidantsManuscript (Other academic)
  • 112.
    Bohlin, Erik
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Johansson, Caisa
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Lestelius, Magnus
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Flexographic ink-coating interactions: Effects of latex variations in coating layers2016In: TAPPI Journal, ISSN 0734-1415, Vol. 15, no 4, p. 253-262Article in journal (Refereed)
  • 113.
    Bohlin, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Enzymes and electron transport in microbial chlorate respiration2008Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Microbial chlorate respiration plays an important role in the turnover of oxochlorates in nature and industrial waste management. This thesis deals with the characterization of the molecular components of chlorate respiration in Ideonella dechloratans. Chlorate respiration utilizes two soluble periplasmic enzymes, chlorate reductase and chlorite dismutase, to convert chlorate to chloride and oxygen. The genes encoding the enzymes participating in the chlorate degradation have been sequenced, and are found in close proximity, forming a gene cluster for chlorate metabolism. This work also includes the successful recombinant expression of three genes from Ideonella dechloratans. Two of the gene products, chlorite dismutase and the C subunit of chlorate reductase, participate in the chlorate respiration. The third gene, which is found close to the gene cluster for chlorate metabolism, encodes a soluble c-type cytochrome. The localization of the gene suggests the corresponding protein as a candidate for a role as electron donor to chlorate reductase. Also, the role of soluble periplasmic c cytochromes of Ideonella dechloratans in chlorate respiration was studied. At least one of the soluble c cytochromes was found capable of serving as electron donor for chlorate reduction. This c cytochrome, and several others, can also donate electrons to a terminal oxidase for subsequent reduction of oxygen, as required for the branched electron flow during chlorate respiration.

  • 114.
    Bohlin, Jan
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Smedja Bäcklund, Anna
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Gustavsson, Niklas
    Novozymes Biopharma AB, Lund.
    Sara, Wahlberg
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Nilsson, Thomas
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Expression, refolding and reconstitution of a c-type cytochrome of Ideonella dechloratansManuscript (Other academic)
  • 115.
    Bohlin, Jan
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Smedja Bäcklund, Anna
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Gustavsson, Niklas
    Novozymes Biopharma AB, Lund, Sweden.
    Wahlberg, Sara
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Nilsson, Thomas
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Characterization of a candidate cytochome c gene associated with the gene cluster for chlorate respiration in Ideonella dechloratansManuscript (Other (popular science, discussion, etc.))
  • 116.
    Bohlin, Jan
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Smedja Bäcklund, Anna
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Gustavsson, Niklas
    Novozymes Biopharma AB, Lund, Sweden.
    Wahlberg, Sara
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Nilsson, Thomas
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Characterization of a cytochrome c gene located at the gene cluster for chlorate respiration in Ideonella dechloratans2010In: Microbiology Research, ISSN 0944-5013, E-ISSN 1618-0623, Vol. 165, p. 450-457Article in journal (Refereed)
  • 117.
    Bohlin, Maria
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Capillary electrophoresis of b2-glycoprotein I: Method Development for Binding Studies2009In: / [ed] Lars G. Blomberg, Niels H. H. Heegaard, 2009Conference paper (Other (popular science, discussion, etc.))
  • 118.
    Bohlin, Maria
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Capillary electrophoresis of beta2-glycoprotein I: Method development and binding studies2006Licentiate thesis, monograph (Other academic)
  • 119.
    Bohlin, Maria
    et al.
    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.
    Affinity studies of beta-2-glycoprotein I using capillary electrophoresis2010In: / [ed] Lars G. Blomberg, Niels H. H. Heegaard, 2010Conference paper (Refereed)
    Abstract

    Beta2-glycoprotein I (b2gpI), also known as apolipoprotein H, is a plasma protein which is involved in the blood coagulation cascade. It binds negatively charged substances such as heparin, DNA, and anionic phospholipids. A number of functions of b2gpI have been proposed, however, the precise function is still not entirely known. Circulating autoantibodies against b2gpI are associated with increased risk of thrombotic events, such as thrombosis and reoccurring fetal loss. It is therefore of interest to functionally characterize b2gpI including the influence of anti-b2gpI autoantibodies on the ligand binding behavior of the protein. The characterization of interactions between biological molecules may be accomplished by capillary electrophoresis under non-denaturing conditions, without the need for immobilization. To avoid charge dependent analyte adsorption to the negative charges of the capillary wall we found the pH hysteresis effect of silica very useful. An acidic pretreatment of the capillary made it possible to perform a subsequent analysis at neutral pH. We were able to perform binding studies between b2gpI and heparin and monosaccharides at different ionic strengths and temperatures in a simple way. We could also study the effect of mildly denaturing conditions on the binding to the different ligands simply by adding sodium dodecyl sulfate (SDS), urea and ACN to the background electrolyte.

    The approach is simple, fast and automatic. The ionic strength, temperature and other parameters such as denaturing agents could easily be changed to characterize the binding between b2gpI and different ligands.

  • 120.
    Bohlin, Maria
    et al.
    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.
    Affinity studies of beta2-glycoprotein I using capillary electrophoresis2010In: / [ed] Lars G. Blomberg, Niels Heegaard, 2010Conference paper (Refereed)
    Abstract

    beta2-glycoprotein I (b2gpI), also known as apolipoprotein H, is a plasma protein which is involved in the blood coagulation cascade. It binds negatively charged substances such as heparin, DNA, and anionic phospholipids. A number of functions of b2gpI have been proposed, however, the precise function is still not entirely known. Circulating autoantibodies against b2gpI are associated with increased risk of thrombotic events, such as thrombosis and reoccurring fetal loss. It is therefore of interest to functionally characterize b2gpI including the influence of anti-b2gpI autoantibodies on the ligand binding behavior of the protein. The characterization of interactions between biological molecules may be accomplished by capillary electrophoresis under non-denaturing conditions, without the need for immobilization. To avoid charge dependent analyte adsorption to the negative charges of the capillary wall we found the pH hysteresis effect of silica very useful. An acidic pretreatment of the capillary made it possible to perform a subsequent analysis at neutral pH. We were able to perform binding studies between b2gpI and heparin at different ionic strengths and temperatures in a simple way. We could also study the effect of mildly denaturing conditions on the binding to the ligand simply by adding sodium dodecyl sulfate (SDS), urea and ACN to the background electrolyte. The approach is simple, fast and automatic

  • 121.
    Bohlin, Maria
    et al.
    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.
    Affinity-CE with phospholipid and carbohydrate ligands: Binding between heparin and anionic liposomes and the anticoagulant protein, beta-2-glycoprotein I2004In: / [ed] E. Kogutowska, L. Blomberg, N. H. H. Heegaard, 2004Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    Binding studies executed by capillary electrophoresis (CE) benefit from flexibility in experimental set-up, wide applicability, and low consumption of reagents. Importantly, the high resolution inherent in CE allows complex mixtures and binding resulting in only small migration changes to be characterized quantitatively. One specific problem, however, that may be encountered when applying CE for the analysis of binding interactions of proteins is the need to avoid interactions other than those between the analyte and the ligand. Thus, protein-wall interactions in unmodified fused-silica capillaries used at neutral pH often invalidate analyses of protein binding. This problem is especially pronounced with basic proteins and proteins containing exposed patches of positive charge. Ways to overcome this are to neutralize the immobilized wall charges e.g. by different wall coatings and/or buffer additives, or by using the pH hysteresis effect, i.e., the slow deprotonation at neutral pH of low pH-treated fused silica. We illustrate the use of the pH-hysteresis effect to avoid adsorption problems in the analysis of a phospholipid- and heparin-binding anticoagulant protein, beta-2-glycoprotein under physiological pH conditions. The approach was useful for characterizing protein-heparin and protein-liposome binding. This will be the basis of using CE methods to evaluate the influence of human thrombogenic autoantibodies against this protein on such interactions and the approach will be also be a useful means to measure the binding activity of different domains and structurally modified variants of this protein and other proteins that suffer from a tendency to stick to fused silica

  • 122.
    Bohlin, Maria
    et al.
    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.
    Capillary electrophoresis-based analysis of phospholipid- and glycosaminoglycan-binding by human beta-2-glycoprotein I2004In: / [ed] E. Kogutowska, L. Blomberg, N. H. H. Heegaard, 2004Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    Human beta-2-glycoprotein I (b2gpI) is a phospholipid- and heparin-binding plasma glycoprotein involved in autoimmune diseases characterized by blood clotting disturbances (thrombosis) together with the occurrence of autoantibodies against b2gpI. With the final goal of assessing autoantibody influence on binding interactions of b2gpI we have studied the development of capillary electrophoresis (CE)-based assays for interactions of negatively charged ligands with b2gpI. Binding studies executed by capillary electrophoresis benefit from flexibility in experimental set-up, wide applicability, and low consumption of reagents.

    Importantly, the high resolution inherent in CE allows complex mixtures and binding resulting in only small migration changes to be characterized quantitatively. One specific problem, however, that may be encountered when applying CE for the analysis of binding interactions of proteins is the need to avoid interactions other than those between the analyte and the ligand. Thus, protein-wall interactions in unmodified fused-silica capillaries used at neutral pH often invalidate analyses of protein binding. This problem is especially pronounced with basic proteins and proteins containing exposed patches of positive charge. In the development of suitable conditions for analysis at neutral pH of b2gpI we found the pH hysteresis behavior of fused silica surfaces useful since the protonated surface after an acid pre-wash counteracted protein adsorption efficiently in contrast to more laborious procedures including acrylamide/dimethylacrylamide coatings that did not permit analysis of this particular protein. This approach made quantitative studies of heparin-b2gpI interactions possible and the principle was shown also to work for detection of b2gpI binding to anionic phospholipids. Utilizing the pH hysteresis effect may be a simple solution to the adsorption problems often encountered in analyses of proteins by CE.

  • 123.
    Bohlin, Maria
    et al.
    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.
    Use of Dimethylacrylamide Coated Capillaries for the Study of beta2-Glycoprotein I with Affinity Capillary Electrophoresis2003In: / [ed] Lars G. Blomberg, Niels H. H. Heegaard, 2003Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    The purpose of this work is to develop a solution method for examining interactions of human beta2-Glycoprotein I (b2gpI) with antibodies and natural ligands under nondenaturing conditions. In the approach, a physiological pH was applied because our intention was to study the interactions between b2gpI and antibodies and the protein must thus be kept in its native state. Preliminary experiments have shown that the recovery of the protein, when analyzed in an uncoated capillary, is poor. At physiological pH the protein is positively charged and most likely it was adsorbed at the negatively charged capillary wall in these experiments. Therefore dimethylacrylamide (DMA) coated capillaries1 are used and analyses could be performed with acceptable recovery. Interaction studies are performed simply by adding the antibody or ligand to the running buffer. The method showed good repeatability and efficiency

  • 124.
    Bohlin, Maria
    et al.
    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.
    Heegaard, N.H.H.
    Utilizing the pH Hysteresis Effect for Versatile and Simple Electrophoretic Analysis of Proteins in Bare Fused-Silica Capillaries2005In: Electrophoresis, 26 (2005) 4043-4049Article in journal (Refereed)
  • 125.
    Bohlin, Maria
    et al.
    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.
    Olsson, Ola
    Heegaard, Niels H.H
    Structure-activity studies of human beta2-glycoprotein I using capillary electrophoresis2011Conference paper (Refereed)
    Abstract

    We have investigated various modes of CE to evaluate the interaction between beta2-glycoprotein I (b2gpI) and a number of anionic ligands to contribute to the elucidation of the structure-function relationship of b2gpI. b2gpI is a plasma protein which is involved in the blood coagulation cascade under normal, physiological conditions, however, its precise function is undefined. It is also involved in pathological conditions such as the so-called anti-phospholipid syndrome, where anti-b2gpI autoantibodies induce a prothrombotic state. Therefore, functional characterization of b2gpI under near physiological conditions is of interest.

    To avoid charge-dependent analyte adsorption to the inner surface of the capillary wall, we have utilized the pH hysteresis effect, where an acidic pretreatment of the capillary made it possible to perform subsequent CE analyses of b2gpI at neutral pH.

    The interaction between b2gpI and the anionic ligand heparin was studied with migration shift ACE, where the ionic strength, temperature and conformation of b2gpI were easily varied. The interaction between b2gpI and phosphatidylcholine/phosphatidylserine liposomes are subject to an ongoing investigation by means of migration shift ACE, frontal analysis CE, partial filling CE and pre-equilibration partial filling ACE.

    We conclude that differential, but relatively low binding affinities that are highly dependent on electrostatic interactions and on a preserved conformation of the protein, characterize its interactions with ligands that in vivo will be present in multiple copies on e.g. cell surfaces. The CE procedure for this study is simple, fast and automatic and quantitative binding affinity parameters are conveniently obtained using small amounts of biological materials.

  • 126.
    Bohlin, Maria E.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Method development for affinity capillary electrophoresis of ß2-glycoprotein I and biological ligands2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The final goal of this study is to establish a microscale analysis method that allows solution phase characterization of interactions between β2-glycoprotein I (β2gpI) and some of its ligands. Human β2gpI is a phospholipid- and heparin-binding plasma glycoprotein. The physiological role of the protein in normal blood coagulation is not entirely known, nor is its role in autoimmune diseases characterized by blood clotting disturbances (thrombosis). Quantitative binding data of β2gpI interactions with some of its ligands may help elucidating the mechanisms behind these diseases and in the development of new approaches for diagnostics, prevention, and therapy.

    In this thesis, capillary electrophoresis (CE) was used as methodological platform for the interaction studies. The analysis of peptides and proteins by CE is desirable due to low sample consumption, possibilities for non-denaturing and highly effective separations. The first objective of this thesis was to find an approach to prevent charge dependent adsorption of β2gpI to the inner surface of the capillaries. Analyte adsorption at the negatively charged inner surface of fused silica capillaries is detrimental to interaction analyses. This phenomenon is especially pronounced in the analysis of basic proteins and proteins containing exposed positively charged domains, such as β2gpI. A new strategy to suppress these solute-wall interactions was devised, investigated and optimized. This strategy exploits the pH hysteresis behavior of fused silica surfaces, by simply performing an acidic pretreatment of the capillary. The results in this thesis show that the acidic pretreatment efficiently prevents protein adsorption.

  • 127.
    Bohlin, Maria E
    et al.
    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.
    Heegaard, Niels H H
    Statens Serum Institut, Copenhagen.
    Effects of ionic strength, temperature and conformation on affinity interactions of β2-glycoprotein I monitored by capillary electrophoresis2011In: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683, Vol. 32, p. 728-737Article in journal (Refereed)
    Abstract [en]

    We have used CE to evaluate the interaction between β2-glycoprotein I (β2gpI) and heparin. β2gpI is a human plasma protein involved in the blood coagulation cascade. It is of interest to functionally characterize the interactions of β2gpI because the exact function is not entirely known and because circulating autoantibodies against β2gpI are associated with an increased risk of thrombotic events.

     

    The effect of the ionic strength, temperature, and conformation of the protein on the interaction between β2gpI and heparin has been studied. The CE procedure for this study is simple, fast and automatic. β2gpI and heparin were allowed to interact during electrophoresis at different ionic strength buffers and at different capillary temperatures. To mimic perturbation of the conformation of β2gpI, different denaturing agents (SDS, ACN and urea) were added to the background electrolyte. While simple 1:1 binding isotherms were obtained at 22 °C the data strongly suggests that at physiological temperature the binding stoichiometry is not 1:1 and/or that cooperative interactions begin to play a role. We found that (i) the KD values differed by a factor of 60 at the ionic strengths studied (ii) β2gpI was resistant to denaturation with SDS and ACN, but was partially denatured by urea and (iii) the KD for the β2gpI-heparin interaction in the presence of urea was 10 times higher than the KD determined at the same conditions without urea added. Therefore, we conclude that the interaction between β2gpI and heparin is dependent on electrostatic interactions and on the conformation of β2gpI. 

  • 128.
    Bohlin, Maria E.
    et al.
    Karlstad University, Division for Chemistry.
    Blomberg, Lars G.
    Karlstad University, Division for Chemistry.
    Heegard, Niels H.H.
    Department of Autoimmunology, Statens Serum Institut, Copenhagen.
    Utilizing the pH hysteresis effect for versatile and simple electrophoretic analysis of protein in bare fused-silica capillaries2005In: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683, Vol. 26, no 21, p. 4043-4049Article in journal (Refereed)
  • 129.
    Bohlin, Maria E.
    et al.
    Karlstad University, Division for Chemistry.
    Kogutowska, Ewa
    Department of Autoimmunology, Statens Serum Institut, Copenhagen.
    Blomberg, Lars G.
    Karlstad University, Division for Chemistry.
    Heegaard, Niels H.H.
    Department of Autoimmunology, Statens Serum Institut, Copenhagen.
    Capillary electrophoresis-based analysis of phospholipid and glycosaminoglycan binding by human β2-glycoprotein I2004In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1059, p. 215-222Article in journal (Refereed)
  • 130.
    Bohlin, Maria
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Johannesson, Ida
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Carlsson, Gunilla
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Heegaard, Nils H H
    Department of Clinical Biochemistry and Immunology, Statens Serum Institut, Copenhagen, Denmark.
    Blomberg, Lars G.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Estimation of the amount of β2-glycoprotein I adsorbed at the inner surface of fused silica capillaries after acidic, neutral and alkaline pretreatment2012In: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683, Vol. 33, no 12, p. 1695-1702Article in journal (Refereed)
    Abstract [en]

    Sample adsorption to the inner surface of fused silica capillaries is a common problem in

    CE when analyzingmacromolecules and is harmful to the analysis. We previously utilized

    the pH hysteresis effect of fused silica to facilitate electrophoresis of the strongly adsorbing

    protein β2gpI in plain-fused silica capillaries at neutral pH. In the present paper, the

    effect of different pretreatments of the capillary on the adsorption of the β2-glycoprotein

    I has been investigated using electroosmosis markers, SDS mobilization, and imaging

    based on indirect immunofluorescence microscopy for direct visualization. The amount

    of β2gpI adsorbed on the surface was probed using all these independent techniques after

    electrophoresis at neutral pH on capillaries pretreated with HCl, background electrolyte

    (BGE), and NaOH. BGE pretreatment was included as a positive control. We found that

    80% or more of the starting material was adsorbed to the inner surface of the silica

    capillaries during electrophoresis after pretreatment with only BGE or with NaOH, but

    after acidic pretreatment the loss was consistently less than 20%. NaOH most efficiently

    removes adsorbed protein between runs. A theoretical calculation of the pH change of

    the BGE showed that electrolysis affects the pH more than the deprotonation of silanols

    during electrophoresis. We conclude that acidic pretreatment of fused silica capillaries

    diminishes adsorption of β2gpI by decreasing charge-dependent wall adsorption.

     

  • 131.
    Bohlin, Maria
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Kogutowska, E.
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Heegaard, N.H.H
    Capillary electrophoresis-based analysis of phospholipid- and glucosaminoglycan-binding by human β2-glycoprotein I2004In: J. Chromatogr. A, 1059 (2004) 215-222Article in journal (Refereed)
  • 132.
    Bohlin, Maria
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Öhman, Marcus
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Hamberg, M.
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Separation of conjugated trienoic fatty acid isomers by micellar electrokinetic chromatographic2003In: J. Chromatogr. A, 985 (2003) 471-478Article in journal (Refereed)
  • 133.
    Boudreau, Jonna
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Germgård, Ulf
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Influence of Various Pulp Properties on the Adhesion Between Tissue Paper and Yankee Cylinder Surface2014In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 9, no 2, p. 2107-2114Article, review/survey (Refereed)
    Abstract [en]

    The strength of the adhesion between the paper and the drying Yankee cylinder is of great importance with respect to the final properties of a tissue paper product. Therefore, the effects of a few potentially important pulp properties have been evaluated in laboratory experiments. Four highly different kraft pulps were used, and the adhesion strength was measured by means of the force required when scraping off a paper from a metal surface with a specifically designed knife mounted on a moving cart. The adhesion strength was observed to increase with increasing grammage and increasing degree of beating of the pulp. It was also found that pulpscontainingmore fines, or with higher hemicellulose content, gave rise to higher adhesion strength.

  • 134.
    Brandberg, Ida
    Karlstad University, Faculty of Arts and Social Sciences (starting 2013), Department of Educational Studies (from 2013).
    Partiklarnas dans: En studie om kemi och dans som estetisk lärprocess i förskolan2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The aim of this study is to increase knowledge about how dance as aesthetic learning process can affect children's explanations of the perception of the matter indestructibility based on a solution process. In a semi-structured group interview, the children were able to explain the same chemical phenomena both before and after the gestation of the phenomenon through dance. The dance in the study portrayed the movements of the particles based on the solution process and evaporation. The result showed that children use three different types of explanation models to explain the chemical phenomenon. The three explanatory models are natural science, animistic and magical explanatory models. The survey shows that the proportion of scientific explanatory models increased after the dance activity. The study suggests that dance as an aesthetic learning process can benefit children's learning in terms of chemistry content in preschool.

  • 135.
    Breen, C.
    et al.
    Sheffield Hallam University, Sheffield, United Kingdom.
    Clegg, F.
    Sheffield Hallam University, Sheffield, United Kingdom.
    Thompson, S.
    Sheffield Hallam University, Sheffield, United Kingdom.
    Järnström, Lars
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Johansson, Caisa
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013). BillerudKorsnäs.
    Exploring the interactions between starches, bentonites and plasticizers in sustainable barrier coatings for paper and board2019In: Applied Clay Science, ISSN 0169-1317, E-ISSN 1872-9053, Vol. 183, article id 105272Article in journal (Refereed)
    Abstract [en]

    Effective food packaging is a major factor in the current global drive to minimise food waste. Starch is an excellent oxygen barrier for packaging but it is brittle and moisture sensitive. The addition of layered minerals and plasticizers can significantly improve the moisture barrier and flexibility of the resulting composite. Some combinations of starch and plasticizer are incompatible but our results show that the addition of bentonite ensures the formation of coherent starch films with much improved moisture barrier regardless of the starch-plasticizer compatibility. It was clearly demonstrated that improvement of the moisture barrier was critically dependent on the layer charge of the bentonite used. Starch was readily accommodated in the interlayer space of bentonites with a layer charge of <0.4 electrons per formula unit but was not adsorbed if the layer charge was above this value. Starch-bentonite-plasticizer coatings prepared using bentonites with the lower layer charge routinely produced higher barriers to water vapour. The water vapour transmission rate (WVTR) of the base paper was reduced from 780 to 340 ± 20 g m2 day−1 when coated with starch alone. This was further reduced to 48 or 66 g m2 day−1 if glycerol or lower charge bentonite, respectively, was added to the starch. Optimised coatings of starch-lower charge bentonite-plasticizer provided WVTR values of ≤10 g m2 day−1 whereas WVTR values for comparative coatings prepared using the higher charge bentonites were three to four times higher (35 ± 7 g m2 day−1). Scanning electron micrographs provided clear evidence for the presence of 60 nm thick supramolecular layers formed from starch-bentonite-plasticizer in the samples coated on either glass or paper. The WVTR values for these low-eco footprint coatings are competitive with proprietary coatings prepared using petroleum derived resins.

  • 136.
    Briscoe, Wuge H.
    et al.
    University of Bristol, England.
    Speranza, Francesca
    University of Bristol, England.
    Li, Peixun
    University of Oxford, England.
    Konovalov, Oleg
    ESRF, France.
    Bouchenoire, Laurence
    University of Liverpool, England.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Klein, Jacob
    Weizmann institute of science, Israel.
    Jacobs, Robert M.J.
    University of Oxford, England.
    Thomas, Robert K.
    University of Oxford, England.
    Synchtrotron XRR study of soft nanofilms at the mica-water interface2012In: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 8, no 18, p. 5055-5068Article in journal (Refereed)
  • 137. Brown, W
    et al.
    Rymdén, R
    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.
    Almgren, M
    Svensk, G
    Static and Dynamic Properties of Nonionic Amphiphile Micelles: Triton X-100 in Aqueous Solution1989In: J. Phys. Chem., 1989, 93, 2512-2519Article in journal (Refereed)
  • 138. Bäcklund, AS
    et al.
    Bohlin, J
    Nilsson, Thomas
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    c-type cytochromes coupled to chlorate reduction in Ideonella dechloratans2008Conference paper (Refereed)
  • 139.
    Carlsson, Carolin
    Karlstad University, Faculty of Technology and Science.
    Konstruktion av en mindre variant av plasmiden pQlacZ-12012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

       The aim with this project was to design a smaller version of pQlacZ-1 in order to later use it as a reporter vector in Ideonella dechloratans.  pQlacZ-1 is a plasmid that is 17,1 kbp big, which might be used as a reporter vector in Ideonella dechloratans to investigate different promoter sequences. This is possible because pQlacZ-1 is a broad host range plasmid and lacks the promoter sequence of the lacZ gene. A problem with pQlacZ-1 is its size which makes it difficult to transform, and especially in Ideonella dechloratans which is difficult to transform at all. A large part of the project has been about finding out how pQlacZ-1 looks like in detail, as this is not well described. Even after this study information about one fragment is missing to get a completely clear picture of how the plasmid is constructed. After formulation of a hypothesis about how the plasmid is constructed, a section that could be removed was identified. The part of pQlacZ-1 that was removed was the lacA and lacY. This was done by a double digestion with SalI and BstBI. The new smaller version of the plasmid, is called pQlacZ-1cc. Theoretically it should be about 13427 bp, which should make it easier to work with. Additional work is required to verify the design of pQlacZ-1cc.

  • 140.
    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.
    Fluorescence Microscopy Applied to the Dynamics of Latex Colloids2003Licentiate thesis, monograph (Other academic)
  • 141.
    Carlsson, Gunilla
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Kursvärdering av examensarbeten för en kandidatexamen2011Conference paper (Refereed)
  • 142.
    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.
    Latex Colloid Dynamics in Complex Dispersions2004Doctoral thesis, monograph (Other academic)
  • 143.
    Carlsson, Gunilla
    Karlstad University, Division for Chemistry.
    Latex Colloid Dynamics in Complex Dispersions: Fluorescence Microscopy Applied to Coating Color Model Systems2004Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Coating colors are applied to the base paper in order to maximize the performance of the end product. Coating colors are complex colloidal systems, mainly consisting of water, binders, and pigments. To understand the behavior of colloidal suspensions, an understanding of the interactions between its components is essential.

  • 144.
    Carlsson, Gunilla
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Programutvärdering av det Naturvetenskapliga programmet 2009-2010: förberedelser, resultat och uppföljning2011Conference paper (Refereed)
  • 145.
    Carlsson, Gunilla
    et al.
    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.
    Järnström, Lars
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Paper Surface Centre. Karlstad University, Faculty of Technology and Science, Department of Chemical Engineering. Karlstad University, Faculty of Technology and Science, Materials Science.
    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.
    Latex Diffusion at High Volume Fractions Studied by Fluorescence Microscopy2006In: J. Colloid Interface Sci. 298(1), 162-171 (2006)Article in journal (Refereed)
  • 146.
    Carlsson, Gunilla
    et al.
    Karlstad University, Division for Chemistry.
    Järnström, Lars
    Karlstad University, Division for Chemistry.
    van Stam, Jan
    Karlstad University, Division for Chemistry.
    Latex Diffusion at High Volume Fractions Studied by Fluorescence Microscopy2006In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 298, no 1, p. 162-171Article in journal (Refereed)
  • 147.
    Carlsson, Gunilla
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Ljungqvist, Carl-Henrik
    Stora Enso, Karlstad Research Center.
    Nyflött, Åsa
    Karlstad University, Faculty of Technology and Science, Materials Science.
    Axrup, Lars
    Stora Enso, Karlstad Research Center.
    Characterization of Micro Fibrillated Cellulose using fluorescence microscopy: Evaluation of pretreatments of Micro Fibrillated Cellulose using fluorescence microscopy2011Conference paper (Refereed)
    Abstract [en]

    The paper making process is well known but the underlying mechanisms are not fully understood. Paper builds up from cellulose fibers and many additives are needed in the process. The interactions between components in the furnish are important. Pulp fibers have a wide size distribution and the finest particle fraction is called fines. The fines used in this study are Micro Fibrillated Cellulose (MFC) from bleached craft pulp.

     

    A model system containing fibers and latex was used together with fluorescence microscopy and image analysis. By studying the motion of a labeled latex particle more can be understood about the internal structure of the system. The system consists of:

    • A water suspension of MFC. At the concentrations used the fines are interacting with each other, forming a gel like structure.
    • Negatively charged labeled latex particles (probes), with radius 0,1 µm.
    • Two types of electrolytes (NaCl and CaCl2). The electrolytes were used for altering the electrical double layer of the charged surfaces in the system.

    Different pretreatments of the MFC has been investigated and evaluated using the movements of the probe in the network of fibers.

  • 148.
    Carlsson, Gunilla
    et al.
    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.
    van Stam, Jan
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Polymer film formation studied with fluorescence microscopy2009Conference paper (Refereed)
    Abstract [en]

    One problem with water-based film-forming systems is the high heat of evaporation, yielding long drying times. Short drying times are commonly important, and solvents with high vapour pressures must be used. This fluorescence microscopy method has successfully been used for studies of low and high volume latex fractions, even for particles with a diameter as small as 100 nm. It is possible to perform statistical analyses from single particles traces, yielding information on interactions with other compounds, as well as changes in the environment of the particle. For fast-drying systems, film formation often occurs under non-equilibrium conditions. The microstructure, frequently due to uncompleted phase separation, is decisive for the film properties. Such microstructures have been found in polymer thin films for optoelectronic devices. Of special interest is the recognition of arrested states and so-called Levy walk diffusion at elevated concentrations, the concentration gradient being a consequence of the drying process

  • 149.
    Carlsson, Gunilla
    et al.
    Karlstad University, Faculty of Technology and Science, 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.
    Rådberg, Weronica
    Ljungqvist, Carl-Henrik
    Axrup, Lars
    Determination of Distribution of Fines in a Paper Structure using Fluorescence Microscopy and Image Analysis2010Conference paper (Refereed)
    Abstract

    When making paper a sheet is formed by draining a specific amount of dilute water suspension of pulp through a wire-cloth. The procedure is well known but the underlying mechanisms are not fully understood. The different particles such as fines, fibers, retention aids and other additives interact with each other during the process. These interactions are important since they impact the properties of the formed paper. The fibers have different sizes and the finest particle fraction is called fines. The fines used in this study are from bleached kraft pulp and are therefore oxidized to some extent.

    By labelling the fines with a fluorophore the movements of individual fines can be followed with video-based fluorescence microscopy even if the size of the fines is below the microscopes resolution limit. [1-3] The fluorophores that has been used are N-Methylisatoic anhydride and fluorescein-5-thiosemicarbazide. N-Methylisatoic anhydride reacts directly with hydroxyl groups on the cellulose chain. Fluorescein-5-thiosemicarbazide reacts with groups like aldehydes and ketones in the cellulose chain, so the chain has to be oxidized before the labeling process. These two fluorephores have different absorption and emission wavelengths. [4]

    The methods for labeling the fibers are easy to perform. The labeled fiber can be seen in the microscope. One problem is that the fibers aggregate, probably due to the method used for labeling. Another problem can be the fading of the flourophores. Both problems will be further investigated. [5]

    The elevated drying process in the paper machine makes it difficult to understand the mechanisms involved. Within this project the understanding will be built up in many steps. The first step is to study the labeled fibers in water. A model system containing fibers and latex will be used to study the behavior in different environments such as different electrolyte concentration and pH.



    References

    [1] Carlsson G., Warszynski P., van Stam J., J. Colloid Interface Sci., 2003, 267, 500-508

    [2] Carlsson G., van Stam J., Nord. Pulp Pap. Res. J., 2005, 20, 192-199

    [3] Carlsson G., Järnström L., van Stam J., J. Colloid Interface Sci., 2006, 298, 162-171

    [4] DeAngelis P. L., Analytical Biochemistry, 2000, 284, 167-169

    [5] Rådberg W., Bsc thesis, Karlstad university, 2010

  • 150.
    Carlsson, Gunilla
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Rådberg, Weronika
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Ljungqvist, Carl-Henrik
    Stora Enso, Karlstad Research Center.
    Axrup, Lars
    Stora Enso, Karlstad Research Center.
    A model system for understanding the distribution of fines in a paper structure using fluorescence microscopy2011Conference paper (Refereed)
    Abstract [en]

    When making paper a sheet is formed by draining a specific amount of dilute water suspension of pulp and wet end additives through a wire-cloth. The procedure is well known but the underlying mechanisms are not fully understood. The pulp stock is composed by different particles such as fines, fibers, retention aids and other additives that interact with each other during the papermaking process. These interactions are important since they influence the properties of the formed paper. Pulp fibers have different sizes and the finest particle fraction is referred to as fines. In this study fines from bleached Kraft pulp were used.

    The fines were oxidized to some extent as a consequence of the Kraft pulp process.A model system containing fibers and latex was used together with fluorescence microscopyand image analysis to study the Brownian motion of a probe in different electrolyte concentrations. The model system was built up of:

    • A water suspension of 1 % fines, negatively charged. At this concentration the fines are interacting with each other, forming a gel like structure.

    • Negatively charged probes with three different sizes (radii 50, 100 and 500 nm).

    • Two types of electrolytes (NaCl and CaCl2). The electrolytes were used for altering the electrical double layer of the charged surfaces in the system.

    By studying the Brownian motion of the probes with different sizes in the network of fines more can be understood about this model system. The knowledge obtained from this model system can be used for further understanding of the paper chemistry mechanisms.

    References

    Carlsson G., Warszynski P., van Stam J., J. Colloid Interface Sci., 2003, 267, 500-508

    Carlsson G., van Stam J., Nord. Pulp Pap. Res. J., 2005, 20, 192-199

    Carlsson G.,  Järnström L., van Stam J., J. Colloid Interface Sci., 2006, 298, 162-171

    Rådberg W., Bachelor thesis, Karlstad University, 2010

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