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  • Polymer and Materials Science  (11)
  • Escherichia coli  (2)
  • 1
    Digitale Medien
    Digitale Medien
    Amsterdam : Elsevier
    FEBS Letters 329 (1993), S. 287-290 
    ISSN: 0014-5793
    Schlagwort(e): Bacterial motility ; Escherichia coli ; Flagellin ; Flagellum ; Phosphatidylglycerol
    Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Thema: Biologie , Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 252 (1996), S. 212-215 
    ISSN: 1617-4623
    Schlagwort(e): Escherichia coli ; Phenothiazine derivatives ; DnaA protein
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The activation of DnaA protein by cardiolipin is inhibited by fluphenazinein vitro. We therefore examined the sensitivity of temperature-sensitivednaA mutants ofEscherichia coli to fluphenazine and other phenothiazine derivatives. Among the eightdnaA mutants tested,dnaA5, dnaA46 dnaA602, anddnaA604, mutants with mutations in the putative ATP binding site of DnaA protein, showed higher sensitivities to phenothiazine derivatives than did the wild-type strain. ThednaA508 anddnaA167 mutants, which have mutations in the N-terminal region of DnaA protein, also showed higher sensitivities to phenothiazine derivatives. On the other hand, thednaA204 anddnaA205 mutants, with lesions in the C-terminal region of the DnaA protein, showed the same sensitivity to phenothiazine derivatives as the wild-type strain. Complementation analysis with a plasmid containing the wild-typednaA gene and phage P1-mediated transduction confirmed thatdnaA mutations are responsible for these sensitivity phenotypes.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 5 (1967), S. 65-67 
    ISSN: 0449-2986
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 5 (1967), S. 583-587 
    ISSN: 0449-2986
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 5 (1967), S. 1937-1949 
    ISSN: 0449-296X
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The copolymerization of tetraoxane with styrene catalyzed by BF3·O(C2H5)2 was studied at 30°C. to determine whether a cyclic monomer can copolymerize with a vinyl monomer. The formation of the copolymer was confirmed by elementary analysis of both benzene-soluble and benzene-insoluble fractions of the polymer obtained. It was found by gas chromatography that a fairly large amount of 4-phenyl-1,3-dioxane and a small amount of trioxane were formed in the present system, in addition to polymers. Roughly a third of the total amount of the monomers reacted was consumed in the formation of methanol-insoluble polymer, a third for 4-phenyl-1,3-dioxane, and another third for trioxane and unknown products which could not be indentified. The formation of these cyclic compounds during the copolymerization may be explained in terms of a back-biting (or intramolecular transacetalization) reaction. The cationic reactivity of tetraoxane was found to be similar to that of styrene on the basis of both the consumption rate of each monomer in the copolymerizing system and the composition of the methanol-insoluble polymer obtained.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 5 (1967), S. 2997-3007 
    ISSN: 0449-296X
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: In the solution polymerization of tetraoxane catalyzed by BF3·O(C2H5)2, trioxane and methanol-insoluble polymer were produced. However, the amounts of these products depend on the nature of solvent used. A critical concentration of tetraoxane is observed for the formation of methanol-insoluble polymer; at less than this critical concentration of tetraoxane no methanol-insoluble polymer is obtained, but trioxane is preferentially produced. This critical concentration of tetraoxane is higher in a more polar solvent, so the amount of methanol-insoluble polymer produced decreases and the amount of trioxane produced increases with increasing the polarity of solvent used. These results may be explained in terms of a stabilization of the active center leading to formation of trioxane by a solvation with solvent.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 8 (1970), S. 157-162 
    ISSN: 0449-296X
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: In the cationic polymerization of trioxane and tetraoxane near room temperature, the equilibrium trioxane concentration is not negligible during polymerization. In this work, tetraoxane was polymerized with BF3 • O(C2H5)2 in various solvents and the equilibrium concentration of trioxane produced during the polymerization of tetraoxane and equilibrated with the growing polyoxymethylene chain was determined. The equilibrium trioxane concentrations were 0.05, 0.13, and 0.19 mole/l. in benzene, ethylene dichloride, and nitrobenzene at 30°C, respectively, and 0.20 mole/l. in thhylene dichloride at 50°C. The values in ethylene dichloride showed that the approximate values of ΔHp and ΔSp0 were -4.2 kcal/mole and -9.7 cal/mole-deg., respectively.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 5 (1967), S. 2989-2996 
    ISSN: 0449-296X
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The amounts of tetraoxane produced in the polymerization of trioxane catalyzed by BF3·O(C2H5)2 were measured in various solvents. The maximum amount of tetraoxane produced depends on the nature of solvent used. This amount was independent of the initial concentration of the catalyst in ethylene dichloride and in nitrobenzene. On the other hand, in benzene, the amount of tetraoxane produced decreased slightly with increasing initial catalyst concentration. This result was explained by the reaction of tetraoxane produced with the residual catalyst as well as with the active center. The maximum amount of tetraoxane produced decreased, other conditions being similar, in the order, nitrobenzene 〉 ethylene dichloride 〉 benzene solvent. This order may be explained in terms of a longer lifetime of the active center in the more polar solvent, leading to the formation of tetraoxane.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 6 (1968), S. 3031-3040 
    ISSN: 0449-296X
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The polymerization of trioxane catalyzed by stannic chloride (SnCl4) in ethylene dichloride was studied and compared with the results obtained with boron trifluoride etherate, BF3·O(C2H5)2, as catalyst. Under the same conditions, the polymerization rate was larger with SnCl4 than with BF3·O(C2H5)2, while at a fixed polymer yield the molecular weight of the polymer obtained by SnCl4 was lower than with the BF3·O(C2H5)2 catalyzed reaction. The overall activation energy of trioxane polymerization with SnCl4 was 11.0 ± 0.8 kcal/mole. The kinetic orders of catalyst and monomer were determined to be close to 2 and 4, respectively. A certain amount of tetraoxane was also produced in an early stage of the polymerization with SnCl4 similar to BF3·O(C2H5)2-catalyzed reaction. However, the maximum amount of tetraoxane produced at 30°C was larger with SnCl4 than with BF3·O(C2H5)2. In addition, a ten-membered ring compound (pentoxane) was isolated in the solution polymerization of trioxane catalyzed by both SnCl4 and BF3·O(C2H5)2. The confirmation of pentoxane formation is strong evidence for the back-biting reaction mechanism.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 5 (1967), S. 1927-1936 
    ISSN: 0449-296X
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: It was determined whether trioxane, a cyclic formal, can copolymerize with styrene, a vinyl monomer, in the presence of BF3·O(C2H5)2 catalyst at 30°C. The methanol-in-soluble fraction after extraction with benzene was found to contain the copolymer of styrene and trioxane, thus demonstrating that trioxane can copolymerize with styrene In this case the amount of the methanol-insoluble polymer was less than that of the total monomer consumed, as determined by gas chromatography. This was found to be caused partly by the formation of the cyclic oligomer, 4-phenyl-1,3-dioxane. The relative reactivity of styrene was qualitatively found to be larger than that of trioxane, not only from the rate of monomer consumption but also from the composition of the methanol-insoluble polymer obtained. In a nonpolar solvent the reactivity of trioxane increased, and the difference in reactivity between the two monomers decreased. Indeed, an apparent monomer reactivity ratio might be obtained from the relationship between the monomer composition and the monomer consumption rate or the composition of the methanol-insoluble polymer, but it did not have a quantitative meaning because of the complexity of the copolymerization reaction.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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