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  • Cell & Developmental Biology  (13)
  • Biochemistry and Biotechnology  (8)
  • Gas chromatography  (6)
Materialart
Erscheinungszeitraum
Schlagwörter
  • 1
    ISSN: 1612-1112
    Schlagwort(e): Aldehydes and ketones ; 2,4-dinitrophenylhydrazine-coated silica gel ; Gas chromatography ; Column liquid chromatography ; Pollution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary After a brief review of several methods described in the literature this paper discusses air-sampling on 2,4-dinitrophenylhydrazine-coated silica gel and identification requirements for aldehydes and ketones most commonly found in industrial pollution. Quantitative analysis of formaldehyde and acetaldehyde either by GC or by HPLC techniques is established using a dynamic system producing test atmospheres and compared with the usual colorimetric determinations.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 27 (1989), S. 37-43 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Methylbromide ; Charcoal tubes ; Pollution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Air sampling of methylbromide using 900 mg HBr-treated activated charcoal tubes, followed by solvent desorption and FID or ECD chromatographic analysis, makes it possible to evaluate concentrations ranging from 0.2 ppm (1 mg×m−3) to 250 ppm (1g×m−3) at ambient temperature even with a high hygrometric level. Thermal desorption does not lead to satisfactory results.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 28 (1989), S. 617-619 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Chlorinated methanes ; Activated charcoal sampling ; Pollution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A sampling method using activated charcoal, followed by percolation with ethanol and FID or ECD chromatographic analysis, depending on the concentrations to be monitored, makes it possible to evaluate concentrations of methylene chloride between 5 and 1000mg m−3, chloroform between 0.1 and 2000mg m−3, and carbon tetrachloride between 0.015 and 1000mg m−3.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 26 (1996), S. 353-357 
    ISSN: 0887-3585
    Schlagwort(e): VEGF ; angiogenesis ; tumor vascularization ; inclusion bodies ; cysteine mutants ; X-ray crystallography ; crystals ; Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Vascular endothelial growth factor (VEGF) is a potent angiogenic factor with a unique specificity for vascular endothelial cells. In addition to its role in vasculogenesis and embryonic angiogenesis, VEGF is implicated in pathologic neovascularization associated with tumors and diabetic retinopathy. Four different constructs of a short variant of VEGF sufficient for receptor binding were overexpressed in Escherichia coli, refolded, purified, and crystallized in five different space groups. In order to facilitate the product on of heavy atom derivatives, single cysteine mutants were designed based on the crystal structure of platelet-derived growth factor. A construct consisting of residues 8 to 109 was crystallized in space group P21, with cell parameters a = 55.6 Å, b = 60.4 Å, c = 77.7 Å, β = 90.0°, and four monomers in the asymmetric unit. Native and derivative data were collected for two of the cysteine mutants as well as for wild-type VEGF. © 1996 Wiley-Liss, Inc.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Chicester [u.a.] : Wiley-Blackwell
    Journal of Molecular Recognition 9 (1996), S. 143-148 
    ISSN: 0952-3499
    Schlagwort(e): polyamines ; steroids ; DNA ; DNA binding ; hydrophobic effects ; Coulombic interactions ; guanidinium ion ; Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Seven new steroidal polyamines derived from bile acids, either lithocholic or deoxycholic acid, have been studied as DNA-binding agents using four complimentary methods: an ethidium displacement assay, observed changes in the thermal denaturation of poly[d(AT)], effects on hyperchromicity of DNA, and circular dichroism. In addition, modelling studies were conducted to examine the electrostatic surface potential of the polycations. The results point to a key role for a large hydrophobic surface area on the steroid in addition to the Coulombic attraction by ammonium and guanidinium groups on the steroid interacting with the polyphosphate backbone.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Chicester [u.a.] : Wiley-Blackwell
    Journal of Molecular Recognition 9 (1996), S. 401-406 
    ISSN: 0952-3499
    Schlagwort(e): derivatized polystyrene ; anti-FVIII ; affinity chromatography ; extracorporeal circulation ; Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Human anti-factor VIII antibodies (anti-FVIII) neutralize Factor VIII (FVIII) procoagulant activity. These antibodies appear in about 5-15 per cent of severely affected patients with haemophilia A treated with FVIII concentrates (Mannucci, 1993). In order to obtain non-thrombogenic materials able to interact specifically with anti-FVIII, amino acids residues that mimic part of the FVIII molecule recognized by anti-FVIII have been grafted. Several cross-linked polystyrenes were functionalized with sulphonate and tyrosine sulphamide groups or tyrosine derivatives sulphamide groups such as methyl ester tyrosine, or the peptides aspartic acid methyl amide tyrosine, tyrosine aspatic acid methyl amide or aspartic acid aspatic acid methyl amide tyrosine.The in vitro removal of anti-FVIII from haemophilic A plasma was performed on different supports. These polymers exhibit strong and selective affinity for the anti-FVIII. The amont of adsorbed anti-FVIII varies with the composition of the polymer and a maximum is achieved for 15-35 per cent of amino acid sulphamide groups. The influence of different chemical groups on the surface of the polymeric solid supports on the adsorption of anti-FVIII was also studied.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1059-910X
    Schlagwort(e): Ultrastructure ; Immunocytochemistry ; Chromatin structure ; Nuclear proteins ; Testis ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: We have followed the fine structural distribution of two nucleosomal core histones, H2B and H3, and of protamines in the course of mouse spermiogenesis by means of specific antibodies and ultrastructural immunocytochemistry.Our results demonstrate that the nuclear labeling density of histone H2B decreases during steps 6-8 and then increases again in step 9-10 spermatids, while the labeling for histone H3 is constant throughout this period. In step 12 spermatids, the anti-H2B antibody labels mainly the central area of the nucleus. The first signs of protamine labeling are present in step 12 spermatids, where the gold grains can be found over the periphery of the nucleus. Later on, protamine labeling constantly increases and, by the end of spermiogenesis, the whole nucleus is labeled.We suggest that the morphological and structural differences between the central area and the periphery of mouse spermatids are, at least partly, due to a difference in the protein moiety associated with DNA. The central area, which is peculiar to the mouse and has been previously considered as a focus of chromatin condensation, represents, however, the last nuclear region containing histones and consequently the last area where the substitution of histones by protamines takes place.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Chicester [u.a.] : Wiley-Blackwell
    Journal of Molecular Recognition 2 (1989), S. 63-74 
    ISSN: 0952-3499
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A consensus sequence has been derived for vertebrate topoisomerase II cleavage of DNA (Spitzner, J. R. and Muller, M. T. (1988) Nucleic Acid. Res. 16, 5533-5556). An independent sample of 65 topoisomerase II sites (obtained in the absence of topoisomerase II inhibitors) was analyzed and found to match the consensus sequence as well as enzyme sites determined in the presence of the anti-tumor drug 4′-(9-acridinyl-amino)-methanesulfon-manisidide (m-AMSA). As originally described, conventional application of the consensus sequence afforded accuracy in the prediction of the locations but not the frequencies of topoisomerase II cleavages. In the present report, we describe a new method which quantitatively discriminates sites from nonsites, called the ‘matrix mean’ method (the mean match of a site to the matrix of base proportions from the original consensus sequence derivation). Furthermore, we derived a second method, called the ‘unique score’ model, which predicts frequency of topoisomerase II activity at a cleavage site. In the unique score method both DNA strands of a site are examined to determine the total number of the consensus positions that match on at least one strand of a potential site. From the new data base of 65 topoisomerase II sites, cleavages were scored for relative cleavage strength. Linear regression analysis showed a significant (p 〈 0.01) correlation between the unique score and cleavage strength. The study was extended to show that the unique score model accurately and quantitatively predicts topoisomerase II sites either in the absence or presence of m-AMSA using the same consensus sequence.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 440-452 
    ISSN: 1040-452X
    Schlagwort(e): Spermiogenesis ; Nuclear condensation ; Chromatin ; Protamines ; Protein-precursors ; Neogastropod mollusc ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: During the process of chromatin cndensation in the spermiogenesis of the neogastropod mollusc Murex brandaris, the nuclear protein complement undergoes a complex series of changes. These changes lead to the appearance of three small protamines in the ripe sperm nuclei. We have characterized this system electrophoretically and at the compositions with antibodies elicited against a specific spermatozoan protamine. Our results indicate that the complex pattern of chromatin condensation during spermiogenesis in this species (M. brandaris) may be modulated by a series of post-translational (and intranuclear) modifications of DNA-interacting proteins, such as precursors to the sperm protamines. The amino acid composition of each sperm protamine is remarkably simple (lys + arg + gly ≥96 mol%). This system of spermiogenic/spermatozoal proteins in the neogastropod M. brandaris clearly differs from that in patellogastropods and archaeogastropods, and it may be helpful in understanding evolutionary changes in the chromatin condensation pattern during the spermiogenesis of gastropod molluscs. © 1994 Wiley-Liss, Inc.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 21 (1986), S. 201-204 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Ethylene oxide ; Active charcoal tubes ; Pollution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Air sampling of ethylene oxide on active charcoal tubes followed by GC analysis is a frequently proposed method. This paper studies just to what extent it can be used, defining its limitations (concentration range, influence of ambient temperature and relative humidity), which are seldom taken seriously into account. This method proves inadequate to determine low pollution levels, i.e. around 2 mg m−3.
    Materialart: Digitale Medien
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