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  • 1
    Electronic Resource
    Electronic Resource
    Investigation of synthesis and light stability of polymeric azo dyes. I. Polymeric urethane-azo dyes (1992)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 197 (1992), S. 159-173 
    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: Ausgehend von 10 unterschiedlich 4′-substituierten 4-[N,N-dihydroxyethyl]aminoazobenzolen wurden durch Umsetzung mit Hexamethylendiisocyanat polymere Azofarbstoffe (M̄n 4200-10200) synthetisiert und die Substituentenabhängigkeit der spektralen Eigenschaften, der Redoxpotentiale und des Ausbleichverhaltens mit entsprechenden monomeren und dimeren Modellverbindungen verglichen. Die Ausbleichung erfolgt durch einen photooxidativen Prozeß. In der Reihenfolge monomerer 〉 dimerer 〉 polymerer Azofarbstoff sinkt die Lichtstabilität durch die Verringerung thermischer Desaktivierungsprozesse sowie durch einen möglichen intramolekularen Energietransfer.
    Notes: Starting from 10 different 4′-substituted 4-[N,N-dihydroxyethyl]aminoazobenzenes, polymeric urethane-azo dyes (M̄n 42000-10200) were prepared by reacting those with hexamethylene diisocyanate. The dependence of spectral properties, redox potentials and photofading behaviour on the kind of substitutents was determined and then compared with corresponding monomer and dimer model compounds. Photofading is caused by a photooxidative process. In the sequence of monomeric 〉 dimeric 〉 polymeric azo dyes, light stability decreases due to a diminution in thermal disactivation processes and in a possible intramolecular energy transfer.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1992.051970114
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  • 2
    Electronic Resource
    Electronic Resource
    Investigation of synthesis and light stability of polymeric azo dyes. II. Polymeric acrylate-azo dyesPart I cf.3. (1992)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 197 (1992), S. 175-184 
    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: Unterschiedlich 4′-substituierte 4-[N-Ethyl-N-(2-acryloyloxy)ethyl]aminoazobenzole dienten als Ausgangsmonomere für Homopolymerisationen und Copolymerisationen mit Styrol und Methylmethacrylat. Die Photobleichung der erhaltenen polymeren Azofarbstoffe (M̄ 4200-9000) wurde mittels einer Xenotest-Apparatur untersucht und mit den entsprechenden Monomeren verglichen. Es wird angenommen, daß die in der Reihenfolge monomerer  -  copolymerisierter  -  homopolymerisierter Azofarbstoff sinkende Photostabilität durch zunehmenden Energietransfer in der Matrix verursacht wird.
    Notes: Different 4′-substituted 4-[N-ethyl-N-(2-acryloyloxy)ethyl]aminoazobenzenes were used as starting monomers for homopolymerization and copolymerization reactions with styrene and methyl methacrylate. The photofading behaviour of the obtained polymeric azo dyes (M̄n 4200 - 9000) was investigated by means of a Xenotest device and compared with that of the corresponding monomers. The decreased photostability in the order monomer  -  copolymer  -  homopolymer was assumed to be caused by an increasing energy transfer in the matrix.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1992.051970115
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  • 3
    Electronic Resource
    Electronic Resource
    Stretching and overstretching of DNA in pulsed field gel electrophoresis. I. A quantitative study from the steady state birefringence decay (1993)
    New York : Wiley-Blackwell
    Biopolymers 33 (1993), S. 1347-1357 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Using a sensitive birefringence instrument, the birefringence arising from the orientation of the DNA chain during electrophoretic transport has been recorded. This birefringence is shown to proceed both from the alignment (stretching) of the molecule in the direction of the electric field and from the extension of the length of its primitive path (overstretching). The contribution of these two processes can be separated in the decay of the birefringence after the end of the application of the electric field. The fast relaxation of the overstretching occurs first and is demonstrated to be the main contribution to the birefringence. The orientation factor of the remaining stretched state and its decay can be quantitatively understood using the biased reptation model. It provides, in addition, a high value for the tube diameter or gel pore size a (4500 ± 450 Å for a 0.7% agarose gel with a c-0.6g dependence in the agarose concentration cg) and a low value for the effective charge per base pair (0.2e as compared to 0.5e using the condensation hypothesis). The contribution of overstretching to the birefringence is also quantitatively interpreted in term of the change in the mean length l of DNA inside a pore size a. The dynamics of decay of this overstretching is well represented by a stretched exponential with a stretching exponent α = 0.44. The mean decay time decreases slightly with increasing fields and scales with the overall DNA length close to N20. © 1993 John Wiley & Sons, Inc.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360330905
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  • 4
    Electronic Resource
    Electronic Resource
    Influence of proline-14 substitution on the secondary structure in a synthetic analogue of alamethicin (1995)
    New York : Wiley-Blackwell
    Biopolymers 36 (1995), S. 547-558 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Due to the bend introduced by proline 14 in the conformation of alamethicin (AcUPUAUQUVUGLUPVUUEQFol), the role of this residue was assumed essential in the barrel-stave model for voltage-gated ion channels. Taking advantage of a previous synthetic alamethicin analogue (L2) in which all eight α-aminoisobutyric(U) Were replaced by leucines (AcLPLALAQLVLGLLPVLLEQFol), another analogue (L5) was synthesized in order to test the effects ofproline-14 substitution by an alanine (AcLPLALAQLVLGLLPVLLEQFol). Previous conductance experiments showed that both high voltage dependence and multistate behavior were conserved. In order to complement these functional results, a conformational study of L5 has been undertaken and compared to L2 using CD. high field nmr, and molecular dynamics. Results show that L5 presents a better ordered structure than L2 particularly in the region of the substitution and in the C-terminal part. These results are discussed as regards the previous hypothesis of the nonessential character of helix bending for the gating of voltage-dependent ion channels. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360360416
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  • 5
    Electronic Resource
    Electronic Resource
    Solid-state conformation of some basic sequential polypeptides (1985)
    New York : Wiley-Blackwell
    Biopolymers 24 (1985), S. 1801-1808 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We have studied the structure of solid films obtained by x-ray diffraction, from several basic polypeptides with a defined sequence. The alterating polypeptides poly(Ala-Lys), poly(Leu-Lys), poly(Val-Lys), and poly(Arg-Leu) all show a cross-β-structure in which layers of hydrophilic side chains alternate with layers containing hydrophobic side chains. The other polypeptides studied are not in the β-conformation and appear to be in the α-helical conformation. The helices obtained from poly(Lys-Ala-Ala) and poly(Lys-Ala-Ala-Lys) appear to be packed in an unusual fashion, which favors interaction between alanine side chains. Such behavior is not found in poly(Lys-Leu-Ala).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360240910
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  • 6
    Electronic Resource
    Electronic Resource
    Stretching and overstretching of DNA in pulsed field gel electrophoresis. II. Coupling of orientation and transport in initial response to the field (1993)
    New York : Wiley-Blackwell
    Biopolymers 33 (1993), S. 1359-1363 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rise of the birefringence following the application of an electric field to DNA in an agarose gel has been quantitatively analyzed to demonstrate the major role played by the chain overstretching. By analyzing the field free decay after short times, we demonstrate that the overshoot is completely due to overstretching. Its time of appearance τov varies with the field and DNA length in fair agreement with the E-lN0ln N0 prediction of Lim et al. [ (1990), Journal of Chemical Physics, Vol. 92, pp. 709-721]. The τov is also the time corresponding to one tube renewal after relaxation of the overstretching. © 1993 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360330906
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  • 7
    Electronic Resource
    Electronic Resource
    Einführung in die Massenspektrometrie (1973)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 7 (1973), S. 192-192 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19730070606
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  • 8
    Electronic Resource
    Electronic Resource
    Römpps Chemie-Lexikon. Von O.-A. Neumüller. Franckh'sche Verlagsbuchhandlung, Stuttgart 1983. 8. Aufl., Band 3, H-L, 868 S., 183 Zeichn., geb. DM 195,- (1984)
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 18 (1984), S. 143-143 
    Details
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ciuz.19840180407
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  • 9
    Electronic Resource
    Electronic Resource
    Über Thio-cyclopentanon-(2)-carbonsäure-(1)-ester und einige Derivate (1960)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 93 (1960), S. 428-434 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Während bei den Cyclopentanon-o-carbonsäureestern die C-Alkylierung und -Acylierung vorherrschen, sind bei den entsprechenden Thio-cyclopentanon-o-carbonsäureestern nur am Schwefel substituierte Abkömmlinge zu erhalten. -  Die Säurespaltung führt zur Thio-cyclopentanon-o-carbonsäure und nicht zu ringaufgespaltenen Produkten.  -  Bei der Oxydation entstehen äußerst stabile Disulfide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19600930224
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  • 10
    Electronic Resource
    Electronic Resource
    Cyclopentanon-o-carbonsäureester, II. Aldehyd-Kondensationen am C-Atom 3 (1960)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 93 (1960), S. 1212-1219 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Während am C-Atom 1 substituierte und am Enol-Sauerstoff alkylierte Cyclopentanon-o-carbonsäureester mit Aldehyden nicht kondensiert werden können, setzen sich unsubstituierte oder in 4.5-Stellung substituierte Ester glatt mit Benzaldehyd, Anisaldehyd und Zimtaldehyd um, wobei Kondensation am C-Atom 3 erfolgt.  -  Erstmalig wird die freie β-Ketosäure von I als Enol isoliert; sie ist beständiger als bisher angenommen wurde.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19600930535
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