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  • 1
    Electronic Resource
    Electronic Resource
    Elektrochemische Darstellung von Cyclopolyphosphanen - Elektrochemische Untersuchung von Phenyldichlorphosphan, o-, m-, p-Bromphenyl-dichlorphosphan sowie tert.-Butyldichlorphosphan (1986)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 542 (1986), S. 167-174 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Different Cyclopolyphosphanes by Cathodic Reduction, Electrochemical Investigation of Phenyldichlorophosphane, o-, m-, p-Bromophenyldichlorophosphane and tert.-ButyldichlorophosphaneThe electrochemical properties of selected dichlorophosphanes R-PCl2 (R = C6H5, o-BrC6H4, m-BrC6H4, p-BrC6H4, t-Bu) have been investigated by the Differential-Pulse-Polarography (DPP) and by cyclic voltammetry. On the basis of the obtained results an electrolysis (cathodic reduction) has been carried out with these substances in a 1,2-dichlorethane/0.1 M tetrabutyl-ammonium tetrafluoroborate solution with a mercury pool. The following cyclopolyphosphanes have been prepared, isolated, and characterized: (C6H5P)5,(4); (o-BrC6H4P)4; (m-BrC6H4P)5,(4,6); (p-BrC6H4P)5,(4); (t-BuP)4.
    Notes: Mit Hilfe von Differential-Puls-Polarographie (DPP) und Cyclovoltammetrie wurde das elektrochemische Verhalten ausgewählter Dichlorphosphan-Verbindungen R-PCl2 (R = C6H5, o-BrC6H4, m-BrC6H4, p-BrC6H4, t-Bu) untersucht. Auf der Grundlage der erhaltenen Werte wurden diese Substanzen in einer 1,2-Dichlorethan/0,1 M Tetrabutylammonium-tetrafluoroborat-Lösung kathodisch an einem Quecksilbersee elektrolysiert. Folgende Cyclopolyphosphane wurden dabei hergestellt, isoliert und charakterisiert: (C6H5P)5,(4); (o-BrC6H4P)4; (m-BrC6H4P)5,(4,6); (p-BrC6H4P)5,(4); (t-BuP)4.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19865421122
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  • 2
    Electronic Resource
    Electronic Resource
    Influence of different tripeptides on the stability of the collagen triple helix. II. An experimental approach with appropriate variations of a trimer model oligotripeptide (1986)
    New York : Wiley-Blackwell
    Biopolymers 25 (1986), S. 1081-1086 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A collagen model peptide comprising three covalently cross-linked chains (Ala-Gly-Pro)8 with a stable triple-helix conformation was utilized as the constant part of elongated model peptides of different composition. The tripeptides Gly-Pro-Hyp, Gly-Pro-Ala, Gly-Pro-Pro, Gly-Pro-Ser, Gly-Ala-Hyp, Gly-Phe-Hyp, Gly-Glu-Hyp, Gly-Ala-Lys, and Gly-Pro-Phe were coupled at the N-terminal to the cross-linked peptide. The transition temperatures determined by CD measurements are higher for the peptides containing the Gly-X-Hyp sequences followed by those with the Gly-Pro-Y sequences. In experiments with combinations of two different tripeptides coupled to the constant part of the cross-linked model peptides higher transition temperatures were observed if the sequence of helix-promoting tripeptides was not interrupted.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360250608
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  • 3
    Electronic Resource
    Electronic Resource
    Protein complexation with DNA phosphates as a cause for DNA duplex destabilization: A thermodynamic model (1989)
    New York : Wiley-Blackwell
    Biopolymers 28 (1989), S. 1653-1665 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complexation of positively charged sites in a protein with the negative DNA phosphate groups shields the phosphate charges. This diminishes interstrand electrostatic repulsions, which stabilizes the duplex. When phosphate shidlding is present in one DNA strand only, the conformation of this strand changes due to a decrease of intrastrand phosphate-phosphate repulsions. This destabilizes the duplex since then the strands differ in conformation. A thermodynamic model is formulated to describe this stabilization/destabilization effect in terms of changed enthalpies and entropies of hybridization. It is found that protein complexation with one DNA strand can indeed lower the TM value of a duplex. The model is applied to the action of helicases (replication), RNA polymerases (transcription), and restriction endonucleases. Mechanisms with unilateral charge shielding are proposed for their duplex-destabilizing properties.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360281002
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  • 4
    Electronic Resource
    Electronic Resource
    A synthetic model of collagen: An experimental investigation of the triple-helix stability (1988)
    New York : Wiley-Blackwell
    Biopolymers 27 (1988), S. 157-163 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Variations I-XVIII of a trimerlike cross-linked collagen model peptide were synthesized and used to investigate the cooperation of different neighboring Gly-X-Y tripeptides. The carboxy-terminal decapentapeptide of the tripe-helical part of collagen type I was chosen as the starting point of sequentially modified elongations. The transition temperatures determined by CD measurements show that the incorporation of the imino acid free tripeptides Gly-Ala-Ala and Gly-Ile-Ala results in a weakening of the triple-helical structure. It is demonstrated that the desired thermal stability of the collagen triple helix requires the “clustered” arrangement of helix-promoting tripeptides, especially of Gly-Pro-Hyp.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360270112
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  • 5
    Electronic Resource
    Electronic Resource
    Prostaglandins and prostaglandin intermediates. XVFor paper XIV of this series see [1]. The content of this publication is in part subject of the GDR-patents 138 768 and 157 096 (Chem. Abstr. 93, 94833 (1980) and 98, 197875 (1983)).. Synthesis of 4-Oxo Carboxylic Acids and γ-Lactones by oxidative cleavage of homoallyl and homopropargyl ketones or alcohols (1985)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 327 (1985), S. 91-95 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A convenient method to convert homoallyl or homopropargyl ketones or alcohols into 4-oxo carboxylic acids or γ-lactones is the oxidative cleavage of the multiple bond with potassium permanganate in diluted sulfuric acid. This is exemplified by the preparation of intermediates for the synthesis of 8-methylprostaglandin C2. The oxidation of the allylic compounds with permanganate is compared with the oxidative cleavage by ozone/hydrogen peroxide, ozone/chromic acid or sodium periodate/potassium permanganate.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19853270112
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  • 6
    Electronic Resource
    Electronic Resource
    Solution-induced changes in the properties of polyethylenes (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 30 (1985), S. 731-740 
    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 chain entanglement states in high density, linear low density, and low density polyethylenes (HDPE, LLDPE, and LDPE) have been modified by recovering the polymers from solutions in trichlorobenzene (TCB) and p-xylene. In the thermodynamically good solvent, TCB, the entanglement density is assumed to be sharply reduced, a condition which is carried over to the corresponding solids. These display transient, but large increments in tensile moduli, slight changes in stress at rupture, and decreases in dynamic mechanical parameters and in elongation at rupture. Scanning calorimetry also shows these solids to have reduced crystallinity. Much smaller property modifications are noted in corresponding samples recovered from p-xylene. This liquid is a poorer solvent, particularly for HDPE and LLDPE. The results indicate that property modifications due to deliberate changes in the entanglement states of the polymers are a general phenomenon in the polyethylenes, and the magnitude of property changes depends on parameters of the molecular weight distribution. Chain branching does not seem to be a leading factor in the sensitivity of properties to modifications in the entanglement states. The property modifications produced by the present solution treatments are viewed as guides to the magnitude and duration of shear refining effects to be expected in HDPE, LLDPE, and LDPE polymers.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1985.070300221
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  • 7
    Electronic Resource
    Electronic Resource
    Rates of property change in plasticized filled PVC compounds (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 33 (1987), S. 2493-2501 
    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: Rheological and mechanical properties of polyvinyl chloride (PVC) compounds vary with the polymer entanglement state at the time of testing. Controlled shearing episodes and thermal histories applied to the compounds produce major property variations. These then relax toward steady-state values at rates which are consistent with diffusion-controlled processes, presumably connected with the development of steady-states in entanglement couplings. Activation energies of 4-7 kcal/mol apply to the proposed re-entanglement processes. Rates of property variation can be altered by the addition of fillers to the compounds, the interactions between polymer and filler being an important factor in this regard. CaCO3 samples with strong affinity for the PVC retard the rate of property variations (i.e., the filler tends to stabilize non-steady-state entanglement couplings). Fillers, surface treated so as not to interact strongly with the polymer, produce lesser effects on relaxation rates. The data indicate the feasibility of controlling both the sensitivity of polymer properties to processing variables, and the rates of property change associated with the attainment of steady-state polymer entanglement morphologies.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1987.070330718
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  • 8
    Electronic Resource
    Electronic Resource
    Thermal degradation of cellulose-containing composites during processing (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 37 (1989), S. 233-240 
    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 strength properties of composites made of untreated cellulose fibers and linear low density polyethylene were investigated as a function of processing parameters. Studies have shown that the strength properties of composites increase with processing time and temperature. The increase in strength is accompanied by the appearance of new infrared absorption bands at 1718 and 1735 cm-1. A linear relationship between the absorbance and yield strength of composites indicates that oxidation, possibly directly at interfaces, takes place and enhances adhesion between the cellulose and polyethylene.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1989.070370118
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  • 9
    Electronic Resource
    Electronic Resource
    Dimorphie des Eises (1896)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 11 (1896), S. 454-455 
    Details
    ISSN: 0863-1778
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.18960110133
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  • 10
    Electronic Resource
    Electronic Resource
    Nachweis und annähernde Bestimmung geringer Mengen von Arsen im Kupfer (1894)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 7 (1894), S. 127-131 
    Details
    ISSN: 0863-1778
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.18940070123
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