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  • 1
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 121 (1979), S. 255-260 
    ISSN: 1432-072X
    Keywords: Purine fermentation ; Xanthine dehydrogenase ; Selenium ; Tungsten ; Molybdenum ; Clostridium acidiurici ; Clostridium cylindrosporum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The xanthine dehydrogenase of Clostridium acidiurici and C. cylindrosporum was assayed with methyl viologen as acceptor. In C. acidiurici the basal activity level was about 0.3 μmol/min x mg of protein. Cells grown on uric acid in the presence of 10-7 M selenite showed a 14-fold increase in xanthine dehydrogenase activity, which decreased with higher selenite concentrations (10-5 M). The supplementation with 10-7 M molybdate or tungstate was without effect. High concentrations of tungstate decreased the xanthine dehydrogenase if selenite was also present. In comparison, high concentrations of molybdate affected only a small decrease in activity level at the optimal concentration for selenite and relieved to some degree the inhibitory effect of 10-5 M selenite. With hypoxanthine and xanthine as substrates for growth again only the addition of selenite was necessary to show a similar increase in xanthine dehydrogenase activity. C. acidiurici could be grown in a mineral medium. Both xanthine dehydrogenase and formate dehydrogenase exhibited the highest level of activity if selenite and tungstate were present in that medium. In C. cylindrosporum the basal activity level of xanthine dehydrogenase was about 0.95 μmol/min x mg of protein. The addition of 10-7 M selenite to the growth medium increased the activity level about 3-fold, but the highest level (3.7 U/mg) was reached if 10-7 M molybdate was also added. The presence of tungstate resulted in a decreased enzyme activity.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Genetics 9 (1975), S. 187-212 
    ISSN: 0066-4197
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 4
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    Berlin : Periodicals Archive Online (PAO)
    Orientalistische Literaturzeitung. 71:2 (1976:März/Apr.) 196 
    ISSN: 0030-5383
    Topics: Linguistics and Literary Studies , Ethnic Sciences , History
    Notes: Besprechungen
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  • 5
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 274 (1978), S. 394-395 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Table 1 demonstrates that the cholesterol present in membranes of intact VS virus and intact human erythrocytes was essentially inaccessible to oxidation by cholesterol oxidase compared with 100% oxidation after disruption of each membrane with 0.3% sodium taurodeoxycholate. Trypsin digestion of ...
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Archives of gynecology and obstetrics 224 (1977), S. 522-523 
    ISSN: 1432-0711
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    International journal of fracture 11 (1975), S. 135-140 
    ISSN: 1573-2673
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Résumé Des essais de fatigue sur des éprouvettes de traction-compression (CT) à entaille aiguë d'alliage d'Aluminium 7075-T6 ont été exécutés à rapports R=σ min/σ max constants et rayon d'arrondi à fond d'entaille ρ imposé. En surveillant le progrès de la fissuration au cours des essais, on a pu déterminé le nombre de cycles auquel l'état caractéristique des tensions près de la racine de l'entaille n'a plus d'influence sur la vitesse de propagation de la pointe de la fissure. Les résultats sont discutés sur base de la théorie de Neuber sur l'effet de support macroscopique. Une analogie avec la mécanique de la rupture en conditions élastique est mentionnée.
    Abstract: Zusammenfassung Man bespricht Müdigkeitsversuche mit konstantem Verhältnis R=σ min/σ max auf Kompaktspannungsproben (CT) aus Aluminium 7075-T6, mit scharfer Kerbwirkung, und einem konstanten Kerbwurzelradius ρ. Durch Überwachung der Rißausdehnung während des ganzen Versuches konnte man die Zahl der Lastspielen festlegen, für die das typische Spannungsstadium an der Kerbwurzel keinen Einfluß mehr auf die Rißspitzengeschwindigkeit hat. Die Ergebnisse werden auf Grund der Theorie von Neuber für Makrounterlageneffekt besprochen. Eine Ähnlichkeit mit der elastischen Bruchmechanik wird hervorgehoben.
    Notes: Abstract Fatigue tests with sharply notched compact tension (CT) specimens of 7075-T6 aluminum were conducted for constant ratios of R=σ min/σ max and constant notch root radius, ρ. By monitoring the crack propagation throughout the tests, the number of cycles at which the characteristic state of stress near the notch root has no further influence on crack tip velocity could be determined. The results are discussed on the basis of Neuber's theory of macro-support effect. An analogy to linear elastic fracture mechanics is pointed out.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 20 (1976), S. 1483-1490 
    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 sizes of dissolved polymers can be estimated a priori at infinite dilution and under theta conditions from existing theories. The effects of concentration can be calculated by assuming that the hydrodynamic volume decreases from a maximum value at infinite dilution toward the theta condition volume, which is reached when the volume fraction of solvated polymer in solution is unity. The predicted hydrodynamic volumes coincide with results of small-angle x-ray scattering and effects of solvent and concentration on gel permeation chromatography elution volumes.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Halosilane Adducts. XIV. Neutral Ligand Complexes of Silicon Containing Six N-Donor Atoms[Si · 3 bipy]4+ is obtained in high yield by the oxidation of Si · 3 bipy with the halogens. [Si · 3 bipy]I4 may also be prepared by directly reacting SiI4 and bipy in the melt. Phen and SiI4 yield [Si · 3 phen]I4 under the same conditions. Mimi and vimi and dimi react with SiI4 in CHCl3 to give [Si · 6 L]I4 (L = mimi, vimi) and [Si · 3 dimi]I4. Thiazole and pyridine and 4-dimethylaminopyridine, on the other hand, yield 1:4 complexes, isoxazole does not react at all. The complex stoichiometry is dependant on the basicity and the structure of the ligands. The 1:4 complexes are easily hydrolysed whereas the N-hexacoordinated complexes are very resistant against solvolysis. They are soluble in water without decomposition. Spectroscopic investigations (i.r., u.v., 1H-nmr) prove the presence of octahedral complex cations of the charge +4 according to the given formulae for the solid and dissolved compounds. Complete anion-exchange is possible. Using ion-exchangers the complexes [Si · 6(3)L](ClO4)4 are obtained.
    Notes: [Si · 3 bipy]4+ wird in hoher Ausbeute durch Oxydation von Si · 3 bipy mit Halogen erhalten. Die Darstellung von [Si · 3 bipy]I4 gelingt auch durch direkte Reaktion von SiI4 und bipy in der Schmelze. Mit phen wird unter gleichen Bedingungen [Si · 3 phen]I4 gebildet. 1-Methyl(Vinyl)-imidazol (mimi, vimi) und 1,1′-Dimethyl-2,2′-diimidazol (dimi) reagieren mit SiI4 in CHCl3 zu [Si · 6 L]I4 (L = mimi, vimi) und [Si · 3 dimi]I4. Mit Thiazol, Pyridin und 4-Dimethyl-aminopyridin werden 1:4 Komplexe, mit Isoxazol keine Reaktion erhalten. Die Komplexstöchiometrie hängt von Basizität und Struktur der Liganden ab. Die 1:4 Komplexe sind hydrolyseempfindlich, die N-hexakoordinierten Komplexe sehr solvolysebeständig. Sie sind unzersetzt in Wasser löslich. Spektroskopische Untersuchungen (IR, UV, 1H-NMR) weisen für die festen und gelösten Titelverbindungen oktaedrische Komplexkationen der Ladung 4+ entsprechend den gegebenen Formeln nach. Über Ionenaustauscher ist vollständiger Anionenaustausch möglich. Mit dieser Methode werden die Komplexe [Si · 6(3)L](ClO4)4 dargestellt.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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