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  • 1
    Electronic Resource
    Electronic Resource
    Mechanism of intercalation: Ion effects on the equilibrium and kinetic constants for the interaction of propidium and ethidium with DNA (1985)
    New York : Wiley-Blackwell
    Biopolymers 24 (1985), S. 1941-1961 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effects of sodium ion concentration on the binding isotherms and association and dissociation reaction rates for the interaction of the closely related intercalating dication, propidium, and the monocation, ethidium, with DNA have been determined by spectrophotometric binding and stopped-flow kinetics methods. The binding of propidium to DNA is best described by a neighbor-exclusion binding isotherm (two base pairs per binding site) with negative ligand cooperatively on binding. The cooperativity parameter is fairly independent of salt concentration, while the log of the observed equilibrium binding constant varies with -log [Na+], with a slope of two for the propidium-DNA interaction. These effects of the sodium ion on the equilibrium binding of propidium with DNA are similar to those previously described for the dication, quinacrine [Wilson, W.D. & Lopp, I.G. (1979) Biopolymers, 18, 3025-3041]. Ethidium behaves, as a function of salt, as a monocation binding to DNA with neighbor exclusion and without ligand cooperativity. Equations are derived for two limiting kinetics models for intercalation involving binding of the intercalator to a preequilibrium, open state of DNA (model I) or binding form a preequilibrium externally associated state of the intercalator with DNA (model II). Model II gives the best fit to all of the kinetic results if it is assumed that the initial external interaction of the intercalator with DNA is similar to the exchange of free and condensed simple counterions. Intercalation then occurs from this state following an opening transition of the base pairs of the double helix. This model predicts a larger effect of salt concentration on the association than on the dissociation reaction, and that is what is experimentally observed. The intercalation conformational change makes a significant contribution to the ionic effects for both the equilibrium binding and the kinetic constants. The dissociation results and the association reaction results under pseudo-first-order conditions could be fit with single exponential curves under the conditions of our experiments.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360241008
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis and properties of model oligomers of poly(naphthylenevinylene)s (1989)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 190 (1989), S. 2995-3003 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Model compounds for poly(1,4-naphthylenevinylene) (1) and poly(2,6-naphthylenevinylene) (2) were synthesized by the Wittig synthesis and studied by UV/VIS spectroscopy and cyclic voltammetry. The values of 2,0 eV for the band gap edge and 0,7 V vs. the saturated calomel electrode for the oxidation potential, which were estimated by an extrapolation of the band gap edge and oxidation potential of model dimer and trimer of 1, are in excellent agreement with the literature values for the polymer. A value of 2,3 eV for the band gap edge of 2 was found by extrapolating the band gap edge of a model dimer and trimer, but the oxidation potential of polymer 2 could not be estimated, because the model trimer was not sufficiently soluble in solvents used. The stoichiometries of the radical cation salts of the model compounds, which were prepared by electrocrystallization, were evaluated from elemental analysis. A single crystal, radical cation salt was obtained for the model dimer of polymer 2.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1989.021901130
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  • 3
    Electronic Resource
    Electronic Resource
    Effect of vulcanization on the low-strain dynamic properties of filled rubbers (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 1191-1212 
    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: A change in the degree of vulcanization in a carbon black-filled rubber is shown not to affect the change of in-phase shear modulus with strain amplitude, provided the amount of filler is kept constant. Similar results are found with the change of out-of-phase modulus and phase angle with strain amplitude. A similar value of change of in-phase shear modulus with strain amplitude (G′0 - G′∞) is found for a vulcanized and unvulcanized tire tread rubber; this behavior is attributed for the breakdown of the secondary three-dimensional carbon black aggregated network. Detailed consideration is given to other factors such as hydrodynamic, shape factor, and relaxation effects which contribute to the difference between the shear modulus of the gum rubber and the filled rubber when all the carbon black structure has been broken down. The consequence of the breakdown of the secondary aggregated structure of carbon black are considered in terms of factors affecting heat build-up in tires.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1972.070160513
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  • 4
    Electronic Resource
    Electronic Resource
    Metal acetylacetonates as latent accelerators for anhydridehyphen;cured epoxy resins (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 26 (1981), S. 979-986 
    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: Twenty-two metal acetylacetonate compounds have been evaluated as possible latent accelerators for epoxy-anhydride solventless resins. Experimental data have revealed that titanium (IV) oxyacetylacetonate, chromium (III), zirconium (IV), cobalt (III), and cobalt (II) acetylacetonates are particularly effective with anhydride cured epoxy resins. When added to the resin at a level of 0.05-0.10% (w/w), they provide very fast gel times at 150-175°C combined with very good storage stabilities (〉 six months) at room temperature. The power factor values of cured resin samples, containing these preferred metal acetylacetonates, have been found to be between 2.0 and 2.5% at 150°C and 60 Hz. Correlation between the catalytic effectiveness of these metal acetylacetonates, as latent accelerators for epoxy-anhydride resins, and their thermal stabilities suggest that decomposition products may be the active species responsible for initiating polymerization in epoxyanhydride resin systems.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1981.070260320
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  • 5
    Electronic Resource
    Electronic Resource
    The mechanism of post cure of viton ARegistered trademark of E. I. du Pont de Nemours & Co., Inc. Fluorocarbon elastomerBased on a lecture delivered at the 2nd International Synthetic Rubber Symposium, London, October 1960, by arrangement with Rubber and Plastics World. (1961)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 5 (1961), S. 460-467 
    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 necessity for oven post-curing Viton A vulcanizates is explained in the following way: The formation of crosslinks is accompanied by the elimination of HF from the polymer. In the subsequent reaction of HF with the magnesium oxide present as acid acceptor water is formed which acts to inhibit the full development of cure unless it is removed from the vicinity of the polymer by post-curing in an open system. Measurement of the rate of elimination of water from the polymer serves as a method of following the development of crosslinking during cure. Approximately two moles of water, derived from four moles of hydrogen fluoride, are associated with the use of one mole of diamine curing agent. This ratio is confirmed by independent estimates of the relationship of crosslinking density to curing agent level based on measurements of swollen compression moduli.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1961.070051612
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  • 6
    Electronic Resource
    Electronic Resource
    Poly[(4-N-ethylene-N-ethylamino)-α-cyanocinnamate]: A nonlinear optical polymer with a chromophoric mainchain. I. Synthesis and spectral characterization (1991)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 29 (1991), S. 1623-1631 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly[(4-N-ethylene-N-ethylamino)-α-cyanocinnamate] was prepared by solution esterification of (4-N-ethyl-N-(2-hydroxyethyl) amino)-α-Cyanocinnamic acid and by melt transesterification of ethyl (4-N-ethyl-N-(2-hydroxyethyl) amino)-α-cyanocinnamate. The melt transesterification generally yielded polymer with a number-average molecular weight of about 10,200 by gel permeation chromatography (GPC) versus polystyrene standards. The polymer was found to be amorphous with a glass transition temperature of about 103°C by differential scanning calorimetry (DSC). The solution esterification generally gave a polymer with a number-average molecular weight of about 2200 by GPC versus polystyrene standards. This polymer was found to have a glass transition temperature varying between 60 and 90°C by DSC. The infrared (IR) spectrum of the polymer made from both methods were analyzed in detail. The 1H- and 13C-NMR spectra of the meltsynthesized ethyl cinnamate derivative polymer are consistent with the reported structure.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1991.080291112
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  • 7
    Electronic Resource
    Electronic Resource
    Main-chain, syndioregic, high-glass transition temperature polymer for nonlinear optics: Synthesis and characterization (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 2899-2906 
    Details
    ISSN: 0887-624X
    Keywords: high-glass transition temperature nonlinear optical polymer ; syndioregic ; mainchain chromophore ; accordion polymers ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new main-chain syndioregic (head-to-head) NLO polymer was synthesized. The glass transition temperature of high molecular weight polymer was found to be 208°C, and the polymer has minimal weight loss at temperatures to at least 250°C owing to the incorporation of hydrogen bonding moieties and rigid bridging groups. The polymer was further characterized using nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). The study of the nonlinear optical properties of this polymer are in progress. © 1993 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080311203
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  • 8
    Electronic Resource
    Electronic Resource
    Laser-Initiated copolymerization of N-vinylpyrrolidone with maleic anhydride and maleimide (1992)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 30 (1992), S. 589-595 
    Details
    ISSN: 0887-624X
    Keywords: laser copolymerization ; charge transfer complexes ; N-vinylpyrrolidone ; maleic anhydride ; maleimide ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This article describes the laser-initiated copolymerization of N-vinylpyrrolidone with maleic anhydride and maleimide via charge transfer complexes. The dependence of copolymer yield on the molar ratios of the monomers in the feed and on the irradiation time is described. Based on the ultraviolet and infrared spectroscopy, and chemical analysis results, a tentative mechanism of polymerization is suggested. The rates of polymerization of several monomer systems are compared. The N-vinylpyrrolidone and maleimide system shows the highest rate of polymerization.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1992.080300410
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  • 9
    Electronic Resource
    Electronic Resource
    Synthesis and properties of poly[arylene ether (N-arylenebenzimidazole)]s (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 3099-3108 
    Details
    ISSN: 0887-624X
    Keywords: poly(arylene ether)s ; poly(N-arylene benzimidazole)s ; high-temperature polymers ; high-performance polymers ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(arylene ether)s containing N-arylenebenzimidazole groups were prepared by the aromatic nucleophilic displacement reaction of two new bis(hydroxyphenyl-N-arylenebenzimidazole)s with activated aromatic difluorides in sulfolane at 200°C in the presence of anhydrous potassium carbonate. The bis(hydroxyphenyl-N-arylenebenzimidazole)s were prepared from bis(o-aminoanilino) arylenes and phenyl-4-hydroxybenzoate. The polymers were soluble in N-methyl-2-pyrrolidinone and m-cresol and exhibited inherent viscosities from 0.37-0.86 dL/g and glass transition temperatures from 219-289°C. Thermogravimetric analyses showed 5% weight losses from 463-506°C in air and 467-522°C in nitrogen. Unoriented thin films exhibited tensile strengths, moduli, and break elongations at 23°C of 10.2-12.5 ksi, 318-365 ksi, and 4-7%, respectively, and at 177°C of 5.1-6.9 ksi, 256-296 ksi, and 1-5%, respectively. A 50 : 50 random copolymer prepared from 1,3-bis(4-fluorobenzoyl) benzene, 1,1'-(4,4'-biphenylene)-bis[2-(4-hydroxyphenyl)benzimidazole], and 5,5'-bis[2-(4-hydroxyphenyl)benzimidazole] exhibited higher moisture absorption and lower tensile properties than those predicted by a rule of mixtures relationship. The chemical, physical, and mechanical properties of these polymers are discussed. © 1993 John Wiley & Sons, Inc.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080311226
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  • 10
    Electronic Resource
    Electronic Resource
    Letters to the editor (1991)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 37 (1991), S. 791-799 
    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: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690370517
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