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  • 1
    Electronic Resource
    Electronic Resource
    Selenium requirement for active xanthine dehydrogenase from Clostridium acidiurici and Clostridium cylindrosporum (1979)
    Springer
    Archives of microbiology 121 (1979), S. 255-260 
    Details
    ISSN: 1432-072X
    Keywords: Purine fermentation ; Xanthine dehydrogenase ; Selenium ; Tungsten ; Molybdenum ; Clostridium acidiurici ; Clostridium cylindrosporum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The xanthine dehydrogenase of Clostridium acidiurici and C. cylindrosporum was assayed with methyl viologen as acceptor. In C. acidiurici the basal activity level was about 0.3 μmol/min x mg of protein. Cells grown on uric acid in the presence of 10-7 M selenite showed a 14-fold increase in xanthine dehydrogenase activity, which decreased with higher selenite concentrations (10-5 M). The supplementation with 10-7 M molybdate or tungstate was without effect. High concentrations of tungstate decreased the xanthine dehydrogenase if selenite was also present. In comparison, high concentrations of molybdate affected only a small decrease in activity level at the optimal concentration for selenite and relieved to some degree the inhibitory effect of 10-5 M selenite. With hypoxanthine and xanthine as substrates for growth again only the addition of selenite was necessary to show a similar increase in xanthine dehydrogenase activity. C. acidiurici could be grown in a mineral medium. Both xanthine dehydrogenase and formate dehydrogenase exhibited the highest level of activity if selenite and tungstate were present in that medium. In C. cylindrosporum the basal activity level of xanthine dehydrogenase was about 0.95 μmol/min x mg of protein. The addition of 10-7 M selenite to the growth medium increased the activity level about 3-fold, but the highest level (3.7 U/mg) was reached if 10-7 M molybdate was also added. The presence of tungstate resulted in a decreased enzyme activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00425064
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  • 2
    Electronic Resource
    Electronic Resource
    Comparative studies on physiology and taxonomy of obligately purinolytic clostridia (1984)
    Springer
    Archives of microbiology 138 (1984), S. 345-353 
    Details
    ISSN: 1432-072X
    Keywords: Clostridium acidiurici ; Clostridium cylindrosporum ; Clostridium purinolyticum ; Purine metabolism ; Selenite ; Antibiogram ; DNA homology ; Taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Eleven strains of obligately purinolytic clostridia have been studied with respect to their assignment to the three type strains of Clostridium acidiurici, C. cylindrosporum, and C. purinolyticum. DNA/DNA-hybridization proved to be the method of choice for differentiation whereas phenotypic characteristics such as spore morphology, substrate spectra, nutritional requirements, product formation, and sensitivity against various antibiotics did not allow unequivocal identification. All strains depended on selenite for growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00410902
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  • 3
    Electronic Resource
    Electronic Resource
    Accumulation and incorporation of 185W-tungsten into proteins of Clostridium acidiurici and Clostridium cylindrosporum (1987)
    Springer
    Archives of microbiology 147 (1987), S. 295-299 
    Details
    ISSN: 1432-072X
    Keywords: Clostridium acidiurici ; Clostridium cylindrosporum ; Tungsten uptake ; Molybdate antagonism ; Formate dehydrogenase ; Tungsten-binding-storage protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Uptake of tungstate by growing cells was unaffected by the presence of molybdate in Clostridium cylindrosporum, whereas in C. acidiurici the accumulation was decreased by molybdate at 10-6 mol/l tungstate and higher concentrations. The labelling pattern of soluble proteins by 185W-tungsten indicated after gel chromatography the presence of three different tungstoproteins in both bacteria. Formate dehydrogenase activity always eluted at a maximum of tungsten labelling. The incorporation of tungsten into formate dehydrogenase containing fractions and a possible tungsten-binding-storage protein was independent of the presence of excess molydate pointing to a genuine role for tungstate in these bacteria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00463491
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  • 4
    Electronic Resource
    Electronic Resource
    Solubility and rate of hydrolysis of chlorine in aqueous sodium hydroxide at 273 K (1981)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 27 (1981), S. 856-859 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690270526
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  • 5
    Electronic Resource
    Electronic Resource
    Intrinsic viscosities and molecular weights of polyvinyl acetatesCommunication No. 1122 from the Kodak Research Laboratories. (1947)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 2 (1947), S. 21-35 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A polyvinyl acetate polymer of medium viscosity was fractionated into sixteen fractions (first series) and three of the larger of these further separated into twenty subfractions (second series). The intrinsic viscosities and the osmotic pressure molecular weights were determined at 25°C. and the relation between them was found to be expressed by the equations: first series: [η] = (1.88 × 10-4) M0.69; second series: [η] = (1.76 × 10-4) M0.68. The data indicate that little, if any, increase in homogeneity is to be expected by further successive fractionations and that the equations applicable to the second fractionation series are representative of essentially homogeneous polyvinyl acetates in acetone. An equation applicable to fractionated and unfractionated vinyl acetate polymers is described that is useful in obtaining the intrinsic viscosity from a single viscosity measurement. Several unfractionated materials from different sources were also studied and the calculated ratios of the viscosity-average to the number-average molecular weight indicate that the degree of heterogeneity of chain-length distribution increases with increasing average molecular weight.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1947.120020105
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  • 6
    Electronic Resource
    Electronic Resource
    A note on the osmometry of polyvinyl acetate-acetone solutions (1949)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 4 (1949), S. 542-542 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1949.120040413
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  • 7
    Electronic Resource
    Electronic Resource
    Silicon-modified carbohydrate surfactants VI: Synthesis of carbosilane, silane, polysilane and non-permethylated siloxane derivatives; the wetting behaviour of epoxy-modified precursor liquids on non-polar surfacesIn remembrance of Professor Dr Edwin Hengge (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 47-58 
    Details
    ISSN: 0268-2605
    Keywords: surfactants ; carbohydrate ; carbosilane ; silane ; wetting ; surface tension ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of carbohydrate surfactants bearing carbosilane, silane, polysilane and non-permethylated siloxane moieties is described. These surfactants consist of three structural elements: (1) a silicon-containing moiety, (2) a spacer and (3) a carbohydrate unit. Additionally two different types of mixed structures have been synthesized: (a) single-chained carbosilane-siloxane surfactants and (b) double-chained combinations of carbo- silanes, silanes and siloxanes. The wetting behaviour of the key intermediates, the allyl glycidyl derivatives, has been investigated by static surface tension (γlv, σ) and wetting tension (γsv-γsl, α) measurements on a non-polar perfluorinated surface (FEP® plate). The contact angles obtained for these pure liquids are not a linear function of the surface tension but depend on the polarity of the substructures. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Silicon-Modified Carbohydrate Surfactants II: Siloxanyl Moieties Containing Branched Structures (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 10 (1996), S. 437-450 
    Details
    ISSN: 0268-2605
    Keywords: siloxanes ; surfactant ; carbohydrate ; amino ; regioselective ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Branched siloxanyl-modified carbohydrate surfactants have been synthesized by coupling mono-, di- and poly-functional siloxanes to carbohydrate units either via a branched spacer or by attaching a separate modifying element to a straight-chained structure. Hydrophilic as well as extremely hydrophobic elements have been incorporated successfully. Siloxanyl-modified carbohydrates bearing a secondary amino function were alkylated in regioselective reactions by different epoxides ranging from glycidol- to siloxanyl-modified allyl glycidyl ether derivatives. Alternatively, carbohydrate-modified piperazinyl structures yielded cyclic subunits after alkylation. Structures bearing two identical hydrophilic groups are accessible by alkylation of carbohydrate-modified bisamides. The derivatives synthesized were characterized by means of GC, NMR and elemental analysis.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Silicon-Modified Carbohydrate Surfactants III: Cationic and Anionic Compounds (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 11 (1997), S. 523-538 
    Details
    ISSN: 0268-2605
    Keywords: silicon-modified ; carbohydrate ; surfactant ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ionic siloxanyl-modified carbohydrate surfactants have been synthesized by alkylation/esterification of precursors containing tertiary amino functions. Depending on the reaction strategy, the siloxanyl moiety is part of the alkylating agent or the substrate. Polyhydroxylated tertiary amines can be quaternized by siloxanyl-modified chloroacetic acid esters or epoxysiloxanes in the presence of glacial acetic acid. The esterification of tertiary amines bearing carbohydrate and siloxanyl subunits by cyclic acid anhydrides yields, after neutralization, carboxylate salts. The reaction of hydroxyl groups and sulfamic acid leads to sulfates. The new substances were characterized by means of 13C NMR spectroscopy, gas chromatography, elemental analysis and their solubility profile. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Silicon-modified carbohydrate surfactants. IV. The impact of substructures on the wetting behaviour of siloxanyl-modified carbohydrate surfactants on low-energy surfaces (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 11 (1997), S. 617-632 
    Details
    ISSN: 0268-2605
    Keywords: siloxanyl-modified ; carbohydrate ; surfactant ; wetting behaviour ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The siloxanyl-modified carbohydrate surfactants investigated consist of the four structural elements: (1) siloxanyl moiety; (2) spacer; (3) carbohydrate unit; and (4) modifying element. By static surface tension (γsν  -  γsβ α) measurements the contact angles of the aqueous surfactant solutions above the critical micelle formation concentration (cmc) on nonpolar perfluorinated surfaces (FEP® plate) were determined. Although the siloxanyl units were found to have a high capacity to level out the interfacial properties, both surface tension and wetting tension react independently to defined changes in the chemical structure of the surfactant molecules. The results of spreading experiments on polyproylene show good correlation with the dependences found by wetting meaurements. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
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