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  • Chemistry  (22)
  • Wiley-Blackwell  (22)
  • International Union of Crystallography
  • Blackwell Publishers Inc.
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Verlag/Herausgeber
  • Wiley-Blackwell  (22)
  • International Union of Crystallography
  • Blackwell Publishers Inc.
Erscheinungszeitraum
  • 1
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 191 (1990), S. 2801-2814 
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Being solubilized in systems of reversed micelles of a surfactant, the macromolecules incorporate into the inner cavities of the micelles, whose size can be changed by varying the degree of hydration, w0 = [H2O]/[surfactant]. The conjugates of proteins (α-chymotrypsin, bovine serum albumin (BSA), monoclonal antibodies to insulin) with linear polyelectrolytes (poly(methacrylic acid), quaternized poly(4-vinylpyridine)) are synthesized in reversed micelles of Aerosol OT (sodium bis(2-ethylhexyl)sulfosuccinate) in the octane with 100% yield. The yield critically depends on the degree of hydration: the reaction does not proceed at low w0, but if w0 exceeds a threshold value (which differs for various macromolecules) the yield increases sharply and reaches 100%. Using the ultracentrifugation it was demonstrated that at low w0 the polyelectrolyte represents a compact globule compressed by the micellar matrix in the inner cavity of a micelle. Under these conditions, there is no space for the protein in a micelle which contains polyelectrolyte, and therefore reaction does not proceed. If w0 exceeds a threshold value the micelles become large enough to entrap the conjugated macromolecules simultaneously. The possibility of regulation of the conjugate composition by variation of w0 (via the size of the micellar matrix) was demonstrated by a conjugate of BSA with quaternized poly(4-vinylpyridine).
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A tool was developed for enhancement of plasmid penetration into an intact cell, based on increasing DNA hydrophobicity via inclusion into a soluble interpolyelectrolyte complex (IPC) with polycations. The characteristics of formation of DNA IPC with synthetic polycations [poly(N-ethyl-4-vinylpyridinium)bromide (PVP) and PVP modified with 3% of N-cetyl-4-vinylpyridinium units (PVP-C)] were studied using ultracentrifugation and polyacrylamide gel electrophoresis methods. The conditions were established under which the mixing of DNA and polycation aqueous solutions results in the selfassembly of soluble IPC species. Incorporation of DNA into IPC results in the enhancement of DNA binding with isolated Bacillus subtilis membranes. A considerable increase in the efficiency of transformation of B. subtilis cells with pBC16 plasmid resulted from incorporation of the plasmid into the IPC with PVP and CVP.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    ISSN: 0947-6539
    Schlagwort(e): liposomes ; phospholipids ; surfactants ; vesicles ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A combination of electrophoresis, dynamic light scattering, conductometry, and fluorescence spectroscopy was applied to investigate vesicles (both in the “solid” and “liquid” states) that had been imparted with electric charge through the incorporation of ionic amphiphiles. These amphiphilic compounds comprised cardiolipin (with two negative charges), sodium dodecyl sulfate (with one negative charge), and cetylpyridinium bromide (with one positive charge). By this means it was discovered that negative vesicles could be converted into neutral vesicles, and then into positive vesicles, by the addition of a cationic surfactant. The amount of cationic surfactant required for the conversion depended upon the mobility of the surfactant within the bilayer. Vesicles were found to be capable of absorbing large amounts of surfactant, both cationic and anionic, before ultimately disintegrating and releasing their contents. Mixtures of cationic and anionic vesicles were able to exchange surfactant, and thereby neutralize each other's charges, without any concurrent vesicle fusion. This phenomenon is reliable only if the vesicles are in the liquid state. Finally, a biphasic exchange process was observed in which a surfactant rapidly departs from one bilayer and then enters another, while a fluorescently labeled lipid travels the reverse path only slowly.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Poly(propargylpyridinium chloride), poly(propargy1-4-vinylpyridinium chloride), poly(propargyl-2,2-bipyridinium chloride), poly(propargyl-1-methyl-2,2-bipyridinium methylsulfate chloride), poly(N-ethyl-vinylpyridinium bromide), and poly(propargyl-2-hydroxyquinolium chloride) were synthesized and a number of simple and complex, tetracyanoquinodimethane ionradical polyelectrolytes were prepared from them. An attempt was made to understand how the molecular structure of these compounds manifests itself in their observed electrophysical properties. Our results show increased electroconductivity in cases of simple and complex ion-radical polyelectrolytes where the conjugated bond polymer “backbone” is in close proximity to dipyridyl polarizing side groups.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 24 (1979), S. 259-267 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Crosslinked polymeric sorbents with macromolecular arrangement favorable for sorption of copper ions have been obtained obtained on the base of copolymer of diethyl ester of vinylphosphonic acid with acrylic acid. The general principle involves interaction of linear polymer and sorbing ions in solution where the segments of the macromolecules are still mobile enough, subsequent fixation of optimal ion uptake conformations of macromolecules by crosslinking of metal polymer complexes, and removal of ions from crosslinked sorbent. Such treatment increases the exchange capacity of the sorbents more than twice and improves essentially its kinetic characteristics in comparison with the same copolymer crosslinked by conventional methods without special arrangement of macromolecules. The rate of the uptake on the sorbents with macromolecular arrangement favorable for ion sorption first increases with increase in the degree of crosslinking and then decreases. Apparently the jise of the crosslinking degree leads to more rigid fixation of the optimum ion uptake conformations of the macromolecules' segments. Further increase of the crosslinking degree alongside with fixation prevents ions from diffusion into the sorbent.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 5 (1981), S. 121-154 
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The general principles of construction of gel-immobilized catalyst systems (GICS) are reported as well as some peculiarities of the polymerization of ethylene and of the dimerization of ethylene and propylene in the presence of these systems.GICS consist of a transition metal complex and a specially designed polymeric support. Advantages offered by gel-immobilized catalyst systems are discussed with respect to homogeneous and microheterogeneous metal complex catalysts.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 13 (1985), S. 137-155 
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Water-soluble nonstoichiometric polyelectrolyte complexes (NPEC) are formed as a result of interaction of opposite charged polyelectrolytes used in nonequivalent ratios. One of the most important properties of NPEC is their ability to participate in intermacromolecular exchange and substitution reactions in aqueous solutions. The kinetics of exchange and substitution reactions has been studied by the method of luminescence quenching. It has been found that such reactions proceed by the contact mechanism and that addition of low molecular electrolytes to the reaction mixtures results in a dramatic increase in the rates of the reactions. The kinetics of the reactions is well described by the equation q = 1-exp(- kt∝) (here q is the degree of conversion and ∝ 〈 1), deduced under the assumption that exchange and substitution occur by the nucleation mechanism and the development of nuclei is inhibited in time. The studied reactions represent a new class of interpolymer reactions and they can be very important, in particular, for understanding the mechanism of functioning of biologically important macromolecules and for the interpretation of the physiological activity of polyelectrolytes.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 3 (1979), S. 41-68 
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: This paper deals with general and also specific aspects of matrix polyreactions on macromolecular templates, namely, mutual assistance of active centres of propagating chains and template units in elementry steps of propagatior. Such assistance has been found in polymerization of 4-vinylpyridine on polyacids and propargyl compounds on poly-4-vinylpyridine. These examples have shown that these kinds of assistance are the crucial points in kinetic template effects.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Interpolymer reactions between poly(acrylic acid) (PAA) or poly(methacrylic acid) (PMAA) and poly(N-tert-butylaziridine) (PTBA) were studied and compared with the corresponding reactions of these polyacids with linear polyethyleneimine (LPEI). In aqueous alkaline and salt media the presence of the bulky non-polar N-substituent in the main chain of PTBA results in a decrease of stability of polyacid-PTBA polyelectrolyte complexes. LPEI, which forms stronger salt bonds with PAA, substitutes PTBA in the PAA-PTBA polyelectrolyte complexes. Addition of simple salts to aqueous solutions of non-stoichiometric polyelectrolyte complexes (N-PEC) PAA-PTBA and PMAA-PTBA at room temperature causes a phase separation due to macromolecular exchange and disproportionation reactions. At elevated temperatures (T = 40 - 60 °C), however, the macromolecular exchange between different N-PEC particles does not occur and phase separation in aqueous salt solution of the N-PEC's PAA-PTBA, PMAA-PTBA is not observed. This is attributed to hydrophobic interactions in polyacid-PTBA complexes due to the presence of the tert-butyl groups in the latter.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 190 (1989), S. 2211-2216 
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The interaction between oppositely charged linear and crosslinked polyelectrolytes and the molecular mechanism of the transport of linear polyelectrolytes into oppositely charged gels were studied. The mechanism represents a “relay-race” transfer of polyion segments from one fragment of the polyelectrolyte network to the other via interpolyelectrolyte exchange reaction. Thus, the whole layer of the formed interpolyelectrolyte complex serves as an active zone. The driving force for the transport is produced by interpolyelectrolyte addition reaction on the solution/gel interface.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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