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  • Chemistry  (19)
  • Polymer and Materials Science  (9)
  • Betriebsanalyse  (8)
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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 26 (1984), S. 191-193 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 24 (1985), S. 461-482 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mechanical creep and creep recovery in small shearing deformations have been studied in unligated clots formed with both thrombin and ancrod. In thrombin clots, both A binding sites (which interact with “a” sites to link monomer units within a protofibril) and B sites (which interact with “b” sites to form links between protofibrils) are exposed to enable formation of linkages; in ancrod clots, only the A sites are exposed. Fine clots (with minimal lateral aggregation of protofibrils), coarse clots (with substantial aggregation of fibril bundles), and clots of intermediate coarseness were compared. Fine thrombin clots showed less creep at short times but more creep at long times than coarse or intermediate clots and had more irrecoverable deformation relative to the initial elastic deformation. Ancrod clots had greater irrecoverable deformation than the corresponding thrombin clots, both fine and coarse. The permanent deformation in fine ancrod clots was enormous, corresponding almost to fluid character; the rate of permanent deformation was larger than that in fine thrombin clots by more than two orders of magnitude. For all types of clots, differential measurements of compliance (or its reciprocal, elastic modulus), as well as the applicability of the Boltzmann superposition principle to calculation of creep recovery, showed that the overall density of structure remained constant throughout the mechanical history; i.e., if structural elements were breaking, they were reforming at the same rate in different configurations. The possibility that the weakness of ancrod clots is attributable to partial degradation of α-chains rather than absence of Bb linkages was eliminated by comparisons of clots made with thrombin, ancrod, and ancrod plus thrombin; the last two showed identical partial degradation of α-chains (by gel electrophoresis), but the first and third had essentially identical initial elastic moduli and creep behavior. Two alternative mechanisms for irrecoverable deformation in fine clots are discussed, involving rupture of protofibrils and slippage of twisted segments, respectively.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1989 (1989), S. 367-374 
    ISSN: 0170-2041
    Keywords: Concave base ; 1,10-Phenanthroline ; Macrobicyclic lactam ; Template cyclization ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Konkave Reagenzien, 2. - Makrobicyclische 1,10-PhenanthrolineDrei makrobicyclische 2,9-disubstituierte 1,10-Phenanthrolin-bislactame 4 wurden mit Gesamtausbeuten bis zu 43% synthetisiert. Dabei wurden zwei Makrocyclisierungstechniken angewandt: 1) Eine Metallionen-gesteuerte Biskondensation (Templatsynthese) eines Diamins 6 mit 1,10-Phenanthrolin-2,9-dicarbaldehyd (5) führte zu neuen makrocyclischen 1,10-Phenanthrolin-Diimin-Komplexen 7 (Schiff-Basen, als Pb2⊕-Komplexe isolierbar), die durch Reduktion mit NaBH4 in die makrocyclischen Diamine 8 übergeführt werden konnten. 2) Die makrocyclischen Diamine 8 wurden mit Dicarbonsäuredichloriden 9 nach dem Verdünnungsprinzip zu den Makrobicyclen 4 umgesetzt. - Die Synthesen der Bicyclen 4, ihre Reaktionen mit Cu⊕ und die relativen Basizitäten von 4 und Vergleichsverbindungen in Ethanol werden beschrieben.
    Notes: Three macrobicyclic 2,9-disubstituted 1,10-phenanthroline-containing bislactams 4 were synthesized in overall yields of up to 43%. Two successive macrocyclization techniques were used: i) metal ion template-assisted bis-condensations of diamines 6 with 1,10-phenanthroline-2,9-dicarbaldehyde (5), leading to new macrocyclic 1,10-phenanthroline-diimine complexes 7 (Schiff bases, isolable as their Pb2⊕ complexes), which were then reduced with NaBH4 to yield the macrocyclic diamines 8, and ii) a high dilution cyclization reaction between the macrocyclic diamines 8 and diacyl dichlorides 9. - Syntheses, complexing abilities towards Cu⊕, and relative basicities of 4 and related compounds in ethanol are reported.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Basel : Wiley-Blackwell
    ISSN: 0173-2803
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Basel : Wiley-Blackwell
    ISSN: 0173-2803
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 104 (1992), S. 309-312 
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1991 (1991), S. 987-998 
    ISSN: 0170-2041
    Keywords: Macrocycles ; Template synthesis ; Conformers ; Sulfonamides ; Pyridines ; Phenanthrolines ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bimacrocyclic concave pyridinebissulfonamides 2 and concave 1,10-phenanthrolinebissulfonamides 4 have been synthesized by bridging macrocyclic pyridinediamines 12 or 1,10-phenanthrolinediamines 16 with alkylenebis(sulfonyl chloride)s 14. In contrast to concave pyridine- and 1,10-phenanthrolinebislactams 1 and 3, the new compounds 2 and 4 exhibit simpler 1H-NMR spectra and sharper melting points due to the absence of amide conformers; in comparison to 1, the basicities of 2 are decreased by a factor of ca. 100. By introduction of donor substituents into the 4-position of the pyridine ring the basicity loss can be easily compensated. The 4-diethylamino substituent increases the basicity of the concave pyridines 1 and 2 as expected (ca. + 4 pK units). Since no deviations from the expected basicity and reactivity for the amino-substituted concave pyridines 1 and 2 have been found, also in these sterically hindered pyridines, the pyridine nitrogen atom is the centre of basicity and reactivity. - The synthesis of new building blocks is described, i.e. 4-diethylamino-2,6-pyridinedicarbaldehyde (9c), the polyether-based bis(sulfonyl chloride) 14b, the monomacrocyclic diamines 12e-h with a pentaethyleneglycol chain or a 4-diethylamino substituent.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 179 (1978), S. 1821-1835 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The scattering behaviour and the critical conditions where gelation takes place have been calculated for polycondensates formed under constraints. The general model includes fully random and stringently restricted reactions as limiting cases. Also polycondensates of glycerine-type monomers are included as special cases. The particle scattering factors of the f-functional random polycondensates differ remarkably from those polycondensates formed under strict constraints. The former show a Kratky plot of a simple curve, independent of the magnitude of the molecular weight and the number of functional groups, and the curve approaches a constant asymptote of u2·Pz(u)=3, the latter exhibits a maximum at u2=6 which becomes more pronounced with increasing molecular weight, (u2 = 〈S2〉zh2, with h, the value of the scattering vector). The scattering curves of the polycondensates formed under weak constraints show at low molecular weights the same behaviour as those formed under stringent constraints, but approach the behaviour of random polycondensates at large molecular weights. The scattering curves of the glycerine-type polycondensates show no deviations in shape from random polycondensates.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 185 (1984), S. 1727-1737 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Poly(diacetylene)s dissolved in common organic solvents undergo random chain scission, if irradiated by UV-light. The pure polymers and their solutions are, however, stable, if they are photoirradiated within the main-absorption band of the polymer backbone. The usual triplet sensitizers, especially in the presence of oxygen, and radical donors such as 2,2′-azoisobutyronitrile (AIBN) enhance the rate of photodegradation. Suitable dyes are able to sensitize the chain-scission in the visible regions as well. Random chain scission occurs also in the dark, but only at temperatures above room temperature and is enhanced by the addition of radical-donors, e.g. AIBN. A mechanism of chain scission, induced by the attack of a radical to a multiple bond of the polyconjugated backbone of the polymer is proposed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 189 (1988), S. 2823-2837 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The commercially available poly(1-octenylene) Vestenamer® formed by the metathetic polymerization of cyclooctene with a tungsten catalyst, is highly crystalline at room temperature; it shows specific properties as a blend component, thus favourably influencing the processing characteristics and the final product quality. Differential scanning calorimetry, infrared and torsion pendulum experiments indicate that the melting temperature and the degree of crystallinity depend on the concentration of trans double bonds, on their distribution along the polymer chain as well as on the sample history. The formation of crosslinks induced by very intensive UV irradiation of 100 μm thin films leads to a reduction of the melting temperature and the crystallinity. A correlation between stiffness (shear modulus G′) and crystallinity was found for samples with varying amounts of trans double bonds.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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