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  • 1
    Electronic Resource
    Electronic Resource
    Metastatic colon carcinoma simulating primary bile duct carcinoma via endoscopic cholangiography (1977)
    Springer
    Abdominal imaging 2 (1977), S. 75-76 
    Details
    ISSN: 1432-0509
    Keywords: Bile duct carcinoma ; Colon carcinoma ; Endoscopic retrograde cholangiopancreatography ; Adenocarcinoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A case of metastatic colon carcinoma simulating primary bile duct carcinoma is presented. The radiographic similarities via endoscopic retrograde cholangiopancreatography include bile duct narrowing and mucosal destruction. A distinguishing feature, however, is failure of the intrahepatic bile ducts to dilate in metastatic carcinoma to the biliary tree.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02256470
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  • 2
    Electronic Resource
    Electronic Resource
    Alternierende copolymerisation von butadien und ethen (1992)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 196 (1992), S. 37-48 
    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: The copolymerization of butadiene and ethene in the presence of the catalyst dineopentyloxyvanadiumoxychloride/triisobutylaluminum was investigated. Basic reaction parameters, such as the [A1]/[V] ratio, the composition of monomer mixture and the polymerization temperature result in a significant influence on the progress of reaction, the conversion of monomers and on the molecular weight and polydispersity of copolymers obtained. NMR measurements demonstrate a high degree of alternation.A maximum of conversion and molecular weight was found by variation of the ratio of catalyst components at [A1]/[V] ≍ 7. An increase of ethene content in the monomer mixture also results in a maximum of conversion but, in contrast, in a continuous decrease in molecular weight. The increase of polymerization temperature from -25°C up to +40°C results in different effects on the yield of copolymers and appropriate data of molecular weight. The microstructure of products with a high content of trans-butadiene units exhibits an increase of 1,2-addition of butadiene and the beginning of crosslinking reactions at temperatures above 20°C.
    Notes: Es wurde die Copolymerissation von Butadien und Ethen in Gegenwart des katalysatorsystems Dineopetyloxyvanadiumoxychlorid/Aluminiumtriisobutyl untersucht. Die Variation der grundlegenden Reaktionsparameter [A1]/[V]-Verhältnis, Zusammensetzung der Monomermischug und Polymerisationstemperature ergab einen signifikanten Einfluß auf den Verlauf der Reaction, den Umsatz der Moomeren die, Molmasse und die Polydispersität der erhaltenen Copolymeren. NMR-Untersuchngen belegen einen hohen Alternierungsgrad.Bei der Variation des Verhaltnisses der Katalysatorkomponenten wurde ein Maximum für Umsatz und die Molmasse bei einem Verhältnis [A1]/[V] ≍ 7 ermittelt. Die Erhöhung des Ethengehaltes in der Moomermischung führt ebenfalls zu einer Erhöhung des Umsatzes. Dabei werden die Molmassen jedoch erniedrigt. Die Variation der Polymerisationstemparatur im Bereich von -25°C bis +40°C ergab für den Umsatz und die Molmasse Abhängigkeiten mit Minimum bzw. Maximum. Bei Polymerisationstemperaturen oberhalb +20°C ist ein Anwachsen der 1,2 -Addition des Butadiens und eine zunehmende Vernetzung der Produkte zu verzeichnen.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1992.051960103
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  • 3
    Electronic Resource
    Electronic Resource
    Massenspektren alicyclischer Verbindungen. VI. Massenspektrometrisches Fragmentierungsverhalten von Chloressigsäurediestern des trans-1,4-Cyclohexandiols (1979)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 321 (1979), S. 953-958 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mass Spectra of Alicyclic Compounds. VI. Mass Spectrometric Fragmentation of Chloroacetic Esters of the trans-1,4-CyclohexanediolThe electron impact mass spectra of some chloroacetic esters of trans-1,4-cyclo-hexanediol and of cyclohexanol are discussed.It was found that the fragmentation process in these compounds is determined by the number of chlorine atoms in the acid and the interactions between the two functional groups.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19793210610
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  • 4
    Electronic Resource
    Electronic Resource
    Liquid crystalline side-group block copolymers with triblock structure: Investigations on the influence of the block arrangement on the morphology and the LC-phase behavior (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 1733-1740 
    Details
    ISSN: 0887-624X
    Keywords: LC side-group block copolymer ; morphology ; phase separation ; LC behavior ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Liquid crystalline triblock copolymers with LC inner block and amorphous outer blocks have been synthesized by “living” anionic polymerization and investigated using DSC, TEM, and small-angle x-ray diffraction. All samples of poly[styrene-block-2-(3-cholesteryloxycarbonyloxy) ethyl methacrylate-block-styrene] (PS-b-PChEMA-b-PS) show liquid crystalline behavior and phase separation between the blocks. Compared to triblock copolymers with PS inner block (PChEMA-b-PS-b-PChEMA) and diblock copolymers (PS-b-PChEMA) the LC block copolymers with PS outer blocks have the same properties. The LC behavior and the morphology do not depend on the block arrangement; they are only influenced by the volume fractions of the blocks. Those samples in which the liquid crystalline subphase is not continuous (spheres) only a nematic phase was found, whereas in all samples with a continuous liquid crystalline subphase, the smectic A phase of the homopolymer was observed. © 1996 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    The β association of (DLLys)10-(LVal)20-(DLLys)10: An nmr study (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 1377-1395 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (DLLys)10-(LVal)20-(DLLys)10, a copolymer of a valine block in the β conformation with randomly coiled flanking blocks of lysine [Kubota, S. & Fasman, G. D. (1975) Biopolymers 14, 605-631], was studied by nuclear magnetic resonance. The peak areas of the N—H and C—H resonances of valine and lysine are concentration-dependent with little chemical shift change. A model is presented describing the aggregation of the copolymer. Additional evidence, obtained by monitoring the spin-lattice relaxation times of amino, amide, γ-methyl-valine, and ∊-methylene-lysine, is consistent with the aggregation model. Hydrodynamic studies are presented which show monomer → oligomer aggregation of four or five subunits.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1976.360150711
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  • 6
    Electronic Resource
    Electronic Resource
    Thermal denaturation of chromatin and lysine copolymer-DNA complexes. Effects of ethylene glycol (1979)
    New York : Wiley-Blackwell
    Biopolymers 18 (1979), S. 1045-1063 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chromatin was thermally denatured in the presence and absence of 1M ethylene glycol using a technique whereby both the hyperchromism and ellipticity are monitored simultaneously. Model complexes containing poly(L-Lys) or poly(L-Lys, L-Ala, Gly) and DNA were similarly melted in order to assist in interpreting the chromatin results. In both cases a general pattern emerged whereby ethylene glycol perturbed the resultant melting profile, showing increased hyperchromicity, ellipticity, and premelt slope. In addition, ethylene glycol destabilizes and reduces the high melting region of polypeptide-bound DNA and the extent of higher ordered structure in model complexes and chromatin. These results emphasize the importance of hydrophobic forces in polypeptide-polypeptide and polypeptide-DNA interactions.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1979.360180503
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  • 7
    Electronic Resource
    Electronic Resource
    Mass Spectrometric Decomposition Processes in Labelled 1-Heptenes (1976)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 59 (1976), S. 987-998 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 70 eV mass spectra of a number of 13C- and D-labelled analogs of 1-heptene have been measured, as well as the metastable transitions in the non-labelled compound. Isotopic distributions in the major fragment ions have been calculated from the high and low resolution data. The results show that considerable skeletal rearrangement must take place before formation of most of the fragment ions. Loss of methyl and ethyl radicals occurs mainly from the two ends of the molecule. Ethylene fragments come primarily from the unsaturated end of the molecule, but show evidence of significant prior skeletal rearrangement. The predicted McLafferty rearrangement accounts for only 2/3 of the C4H8+ ions formed, less for the C3H6+ ions. At least 80% of C4H9+ ions appear to be formed by allylic cleavage, as expected, but this mechanism can only account for a maximum of 20% of the formation of the complementary ion C3H5+. Both, this latter ion and C3H6+, are probably generated by loss of hydrogen from C3H7+.Figures obtained for label retention in 1-[13C]- and 1-D-labelled analogs were nearly identical for most fragment ions, probably indicating that the hydrogen atoms in position 1 remain on C(1) even following skeletal rearrangement. A similar result was found for the 7-[13C]- and 7-D-labelled compounds. The main exceptions in the case of the products labelled in position 1 (C4H7+, C3H3+) seem to be due to initial loss of an hydrogen atom from this position followed by further fragmentation.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19760590403
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  • 8
    Electronic Resource
    Electronic Resource
    Der Einfluß von Donatoren und Acceptoren auf die Copolymerisation von Styrol und Maleinsäureanhydrid. I. Der Einfluß von Sauerstoff als Acceptor bei der Polymerisation in polaren Lösungsmitteln (1980)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 31 (1980), S. 572-577 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The spontaneous thermal polymerization of the system styrene/maleic acid anhydride in the presence and absence of oxygen was investigated. The acceleration of the reaction by oxygen cannot be explained by the formation of peroxy compounds. The initiation of the reaction by the cationic styrene radical and an anionic radical of maleic acid anhydride is discussed.
    Notes: Die spontane thermische Polymerisation des Systems Styrol/Maleinsäureanhydrid wurde in Gegenwart und Abwesenheit von Sauerstoff untersucht. Durch entsprechende Untersuchungen konnte gezeigt werden, daß die Beschleunigung der Reaktion unter Sauerstoffeinfluß nicht auf gebildete peroxidische Verbindungen zurückgeführt werden kann. Es wird die Reaktionsauslösung über ein Kationenradikal des Styrols und ein Anionenradikal des Maleinsäureanhydrids diskutiert.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1980.010310908
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  • 9
    Electronic Resource
    Electronic Resource
    13C-NMR-Untersuchungen an Styren-Maleinsäureanhydrid-CopolymerenVortrag auf dem Mikrosymposium „Radikalische Polymerisation“, März 1980 in Leipzig. (1981)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 32 (1981), S. 277-280 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Based on 13C NMR investigations the microstructure of the polymer chain is shown to be controlled by varying the monomer composition. The copolymerization of maleic anhydride with styrene in excess results in distinct deviations from the alternating structure.
    Notes: Anhand von 13C-NMR-Messungen wird gezeigt, wie durch Variation der Monomerzusammensetzung die Mikrostruktur der makromolekularen Kette vorbestimmt werden kann. Bei unter Überschuß von Styren ablaufender Copolymerisation mit MSA entstehen sicher nachweisbare Abweichungen von der alternierenden Struktur.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1981.010320509
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  • 10
    Electronic Resource
    Electronic Resource
    Besonderheiten bei der Copolymerisation mit Maleinsäureanhydrid (1981)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 32 (1981), S. 300-307 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: In the copolymerization of maleic anhydride with weak donor monomers the rate of polymerization depends in different ways on the monomer composition. Three principally different types of plots demonstrating the dependence of the overall rate of polymerization on the composition of the monomer mixture in the systems styrene/MSA, vinylacetate/MSA and acrylamide/MSA were obtained. The explanation of these differences is based on separate association of monomers in the growth reaction and dominating cross termination as compared with the termination of unique monomers.
    Notes: Bei der Copolymerisation von Maleinsäureanhydrid mit schwachen Donatormonomeren wird die Polymerisationsgeschwindigkeit in unterschiedlicher Weise von der Monomerzusammensetzung beeinflußt. Es werden drei grundsätzlich unterschiedliche Kurventypen für die Abhängigkeit der Bruttopolymerisationsgeschwindigkeit von der Zusammensetzung der Monomermischung an den Systemen Styren/MSA, Vinylacetat/MSA und Acrylamid/MSA gefunden und auf der Basis der getrennten Anlagerung der Monomere im Wachstumsschritt und einem gegenüber den Abbruchschritten gleichartiger Radikale erhöhten gekreuzten Abbruchschritt diskutiert.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1981.010320603
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