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  • Chemistry  (7)
  • 1980-1984  (3)
  • 1970-1974  (3)
  • 1960-1964  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Temperature dependence of nuclear magnetic resonance absorption in coal (1962)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 6 (1962), S. 94-97 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The proton magnetic resonance in the vitrain of Yūbari caking coal and its residue of pyridine extraction has been studied over the range 90 to 423°K. At lower temperature the absorption line consists of a broad component. At higher temperature this component begins to decrease rapidly in the line width and resolves into two components. This rapid narrowing of the absorption line width suggests a glass transition attributed to the molecular motion in coal. The variation of the second moment of the absorption line with temperature reflects the line width variation. From these results some information on the molecular motion and arrangement in coal have been obtained.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1962.070061910
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  • 2
    Electronic Resource
    Electronic Resource
    The differential refractive index increments of statistical styrene/acrylonitrile/methyl methacrylate terpolymers (1972)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 25 (1972), S. 163-169 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Das Brechungsindexinkrement von acht verschieden zusammengesetzten Terpolymeren aus Styrol, Acrylnitril und Methylmethacrylat wurde in Dimethylfoirmamid und in Butanon bestimmt. Aus der infrarotspektroskopisch ermittelten Zusammensetzung der Copolymeren und den Brechungsinkrementen der Homopolymeren wurden die Brechungsinkremente der Terpolymeren berechnet. Das ptrrtielle azeotrope Terpolymere besitzt ein konstantes Brechungsinkrement während der Terpolymerisation, während die aus anderen Monomermischungen erhaltenen Werte sich mit dem Umsatz ändern.
    Notes: The differential refractive index increment was measured for statistical styrene/acrylonitrile/methyl methacrylate terpolymers of eight different compositions in dimethylformamide and in butanone. With the terpolymer composition obtained from infrared absorption and the differential refractive index increments of the homopolymers, the differential refractive index increments of terpolymers are calculated. The partial azeotropic terpolymer gives a constant value in the course of terpolymerization. The differential refractive index increment of a terpolymer synthesized from other monomer feed than the azeotropic composition changes with conversion.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1972.050250115
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  • 3
    Electronic Resource
    Electronic Resource
    Direct polymerization of N-carboxy anhydride of L-glutamic acid (1981)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 182 (1981), S. 2127-2137 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A new method of polymerization of the N-carboxy anhydride (NCA) of glutamic acid is presented by which poly(glutamic acid) is obtained directly from the NCA without protecting its carboxyl group. The principle underlying is that by adjusting the mole ratio of the initiator butylamine, [I], to the monomer, [A], butylamine can be used as protecting agent for the carboxyl group of the NCA so that the rest of butylamine acts as initiator in the heterogeneous polymerization in acetonitrile. Quantitative conversion was obtained for an [A]/[I] ratio of 1. In analogy to other heterogeneous polymerizations of NCAs in acetonitrile, this is due to the formation of the helix during polymerization, which was confirmed by IR absorption and X-ray diffraction measurements. As the [A]/[I] ratio increases, the conversion, the helix content of the resultant polymer, and the amount of butylamine combined with it decrease drastically. It is suggested that “copolymerization” of the amine-protected and unprotected NCAs occurs, giving rise to a partially helical chain, whose contents of the amine-protected side chains and accordingly of the helix are the higher the smaller the [A]/[I] ratio.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1981.021820802
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  • 4
    Electronic Resource
    Electronic Resource
    Dilute solution of amylose in dimethylsuldoxide (1973)
    New York : Wiley-Blackwell
    Biopolymers 12 (1973), S. 1177-1195 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Measurements of light scatting, sedimentation equilibrium, sedimentation velocity, and viscosity were carried out on fractions of native amylose in dimethylsulfoxide at 25°C. The data for statistical radius as a function of weight-average molecular weight Mw suggested a stiff nature of this biopolymer in the solvent studied when interpreted in terms of Kirste's recent calculations with a stiff chain model. The data for sedimentation coefficient were consistent with this suggestion, and when analyzed in terms of the theory Hearst and Stockmayer for wormlike chain, a value of 233 Å2 was obtainedd for a/λ, where a is the length of a monomer unit projected on the chain axis and (2λ)-1is the persistence length of the wormlike chain. The intrinsic viscosity data gave a high a value as 0.91 for the exoponent in the Houwink-Mark-Sakuarada equation, in Substantial agreement with Cowie's prenious work.We attempted to interpret these data by use of the Eizner-Ptitsyn equation for wormlike chains, with omission of the free-drainage term and introduction of the a/λ value obtained from sedimentation data. It was found that, except in the region of Mw above one million, the observed values were fitted well by the E-P theory with a = 1.4 Å and (2λ)-1 = 87 Å. The disagreement in the high-molecular-weight region was tentatively attributed to excluded volume effect. The a value obtained suggests that the molecular conformation of amylose in dimethylsulfoxide is predominantly helical, in contrast to that of the same polymer in aqueous solutions of simple electrolyte. It was also found that a similar value of a was derived from our data for the second virial coefficient and partial specific volume if the molecule was assumed to be essentially rodlike.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1973.360120520
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  • 5
    Electronic Resource
    Electronic Resource
    Reversible oxygenation of heme bound to polyvinylpyridine and polyvinylimidazole (1974)
    New York : Wiley-Blackwell
    Biopolymers 13 (1974), S. 2147-2159 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The interaction between heme bound to poly-4-vinylpyridine (PVP) or poly-N-vinyl-2-methylimidazole (PVMI) and molecular oxygen (O2) was studied. In this paper, the reactions of some types of heme with O2 in organic solvents, particularly in N,N-dimethylformamide (DMF) were discussed. The free heme not bound to an axial base was easily oxidized irreversibly to hemin in DMF with bubbled O2. The hemochromogens complexed with pyridine, imidazole, or their polymeric derivatives such as PVP and PVMI bound O2 to one of the axial coordination sites. The characteristic absorption band assignable to the resulting oxygenated heme was observed at 402 nm. This absorption band could be changed back to the characteristic band of the reduced hemochromogen at 418 nm by removing O2 dissolved in the DMF solution by a vacuum or by a stream of nitrogen. Thus, the hemochromogens bound to the synthetic polymers were found to adsorb and desorb O2 reversible in DMF.When the polymeric ligands were used, the equilibrium constants in the complexation of heme with these polymers were about 102 times as large as those of the corresponding monomeric ligands. The oxygenation rates and the capacities of O2 of the polymeric hemochromogens were larger than those of the monomeric hemochromogens. In addition, the oxygenation rate of the polymer complex was changeable owing to the conformational change of the polymeric ligand; this rate increased about ten times under the optimal condition.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1974.360131015
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  • 6
    Electronic Resource
    Electronic Resource
    Biosynthesis of the Indole Alkaloids. Cell-free Systems from Catharanthus roseus PlantsFor preliminary reports of this work, see [1-4]. (1982)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 65 (1982), S. 2088-2101 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cell-free systems from Catharanthus roseus plants are utilized for various studies relating to the biosynthesis of indole alkaloids. Tryptamine (5) and secologanin (6), two fundamental building units, are shown to be incorporated into the alkaloid vindoline (7). In another study, catharanthine (18) and vindoline (7) are utilized by this enzyme system and coupled to the important bisindole biointermediate 3′,4′-anhydrovinblastineThe previously [20] used name for 17, 3′, 4′-dehydrovinblastine, is incorrect. (17). The latter substance is, in turn, incorporated and converted to the natural alkaloids leurosine (8), Catharine (9) and vinblastine (10), thereby providing information about the biosynthesis of these complex molecules. High pressure liquid chromatography assay of the enzymic mixture sheds light on the enzymes involved in the coupling of 18 and 7.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19820650716
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  • 7
    Electronic Resource
    Electronic Resource
    Total Synthesis of Indole and Dihydroindole Alkaloids. XVIIIPart XVII: [1].. Isomers and analogues of vinblastine (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 366-374 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and conformational analysis of (3′R)-3-hydroxyleurosidine (5), (3′S)-3-hydroxyleurosidine (10), (3′S)-3-acetoxy-4′-deoxyleurosidine (15), (3′R)-3-acetoxy-4′-deoxyleurosidine (23), (3′R)-3-acetoxy-4′-deoxyvinblastine (16), (3′S)-3-acetoxy-4′-deoxyleurosidine (28) is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19800630206
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