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  • 1
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Crystal Growth 29 (1975), S. 215-216 
    ISSN: 0022-0248
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Inorganic and Nuclear Chemistry 31 (1969), S. 3855-3859 
    ISSN: 0022-1902
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Naturwissenschaften 42 (1955), S. 624-624 
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 60 (1968), S. 99-110 
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Das sich bei Phosphormangel und fast vollständiger Abwesenheit von Kupfer anreichernde Chromogen von A. chroococcum ist neben vielleicht noch einigen anderen Stoffen vor allem Brenzcatechin und nicht Tyrosin, wie bisher angenommen wurde. Der schwarzbraune Farbstoff ist darum auch kein Melanin im klassischen Sinne, sondern eine den Grauhuminsäuren ähnliche Substanz. A. agilis bildet kein Brenzcatechin und keine anderen über Chinone zu Farbstoffen kondensierbaren und polymerisierenden Phenole. Brenzcatechin wird durch diese in ihrer Grundatmung wirksamere Azotobacter-Art in jedem Falle zerstört, wenn es dem Nährsubstrat zugesetzt wird. Ähnliches geschieht durch A. chroococcum nur dann, wenn die Zellen mit viel Phosphat ernährt werden. Brenzcatechin und der daraus entstehende schwarzbraune Farbstoff werden von den bei Phosphormangel sich entwickelnden rundlichen, dickwandigen, schwächer atmenden und als Cysten angesprochenen Zellen von A. chroococcum gebildet. Sie enthalten reichlich Fett und PHB, jedoch kein Glykogen und keine „Nadi”-positiven Körnchen (Cytochromoxydase). Umgekehrt speichern die bei Phosphorüberfluß sich entwickelnden ovalen, dünnwandigen und stärker atmenden Zellen Glykogen, weniger PHB, kein Fett und enthalten reichlich „Nadi”-positive Körnchen. Auch für Azotobacter ist Brenzcatechin ein Zellgift, das aber infolge seiner augen-blicklichen Überführung in den dunklen, humusartigen Farbstoff schnell entgiftet wird. Nicht nur biochemisch, nämlich in Anwesenheit lebender Azotobacter-Zellen, sondern auch rein chemisch kann bei mittlerer Temperatur, bei gepufferter neutraler Reaktion und mit verhältnismäßig viel Eisen-Ionen in der Reaktionslösung ein schwarzbrauner Niederschlag aus Brenzcatechin entstehen, hann allerdings langsamer. Kupfer, für die schneller verlaufende biochemische Reaktion unentbehrlich, scheint bei der rein chemischen keine Rolle zu spielen. Bei der rein chemischen wie auch vermutlich bei der biochemischen Oxydation des Brenzcatechins zum Chinon verbindet es sich unter den gegebenen Versuchsbedingungen mit nucleophilen Stoffen. Auf diese Weise dürften wesentliche Mengen des Stickstoffs und anderer Pflanzennährstoffe in den fruchtbaren Bodenhumus gelangen.
    Notes: Summary The chromogen of A. chroococcum which concentrates under conditions of phosphorus deficiency and almost complete lack of copper is not tyrosine, as previously accepted, but is catechol in the first place. Possibly some other compounds of chromogenic nature are produced in smaller quantities. Hence, the black-brown pigment is not a melanin in the classic sense but a substance related to the gray humic acids. A. agilis does not produce catechol or any other phenol that by condensation and polymerization of the corresponding quinone is converted into pigment. This Azotobacter species which compared with A. chroococcum has a more active basic respiration destroys the catechol when added to the nutrient substrate. A. chroococcum acts the same way only in case of abundant phosphorus supply. Catechol and the black-brown pigment developing from it are produced by cells of A. chroococcum known as cysts that are round, possess thick cell walls and have a weak respiratory activity. They contain plenty of fat and PHB, but no glycogen, and do not possess any granules positive in the „Nadi”-reaction (Cytochromoxidase). On the other hand, with abundance of phosphorus, oval cells with thin cell walls develop exhibiting a stronger respiration. These cells store up glycogen, but less PHB, and no fat. They have plenty of “Nadi”-positive granules. To Azotobacter as to many other organisms catechol represents a cell poison; however, it is quickly detoxified by its immediate conversion into the dark humus-like pigment. Not only in the presence of living cells of Azotobacter but even in a pure chemical reaction a dark-brown precipitate is produced from catechol in neutral and buffered solution provided that Fe-ions are present in a relatively high concentration. This process, however, takes more time. Copper is indispensable in the quick biochemical reaction but appears to be of no importance for pure chemical conversion. In the chemical conversion and presumably also in the biochemical oxidation of catechol into quinone there is a combination with nucleophilic substances under the chosen experimental conditions. By this process considerable amounts of nitrogen and of other plant nutrient elements might be incorporated into the productive soil humus.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 9 (1974), S. 1696-1700 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Large stoichiometric MgAl2O4 spinel single crystals of high crystalline perfection have been grown by the Czochralski method. By means of X-ray diffraction topography the dislocation arrangement, Burgers vector directions and glide planes were investigated in relation to crystal growth conditions. Fast cooling rates generated prismatic dislocation hexagons in the central region of as-grown crystals. For the first time a new glide system in spinel following {311} planes was observed.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 359 (1968), S. 160-177 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hitherto unknown MgPdF6 [a = 4.98, c = 13.48 Å], CaPdF6 [a = 5.19, c = 14.59 Å], ZnPdF6 [a = 4.95, c = 13.69 Å] and CdPdF6 [a = 5.08, c = 14.39 Å] have been prepared, all of the hexagonal LiSbF6-type of structure. In addition, newly prepared are Li2PdF6 [a = 10.09, b = 4.64, c = 4.63 Å; β = 117°] and Li2PtF6 [a = 10.23, b = 4.68, c = 4.65 Å; β = 117°], both of the monoclinic Na2SnF6-type of structure. It is confirmed that Na2PdF6 is isotypic with Na2SiF6. The compounds are partly yellow, partly brownish-yellow.
    Notes: Neu dargestellt wurden die hexagonalen Verbindungen MgPdF6 [a = 4,98 Å, c = 13,48 Å], CaPdF6 [a = 5,19 Å, c = 14,59 Å], ZnPdF6 [a = 4,95 Å, c = 13,69 Å] und CdPdF6 [a = 5,08 Å, c = 14,39 Å], die alle zum LiSbF6-Typ gehören und teils hellgelb, teils bräunlichgelb aussehen. Ebenfalls neu erhielt man die zum monoklinen Na2SnF6-Typ gehörenden Verbindungen Li2PdF6 [a = 10,09 Å, b = 4,64 Å, c = 4,63 Å, β = 117°] und Li2PtF6 [a = 10,23 Å, b = 4,68 Å, c = 4,65 Å, β = 117°]. Die Isotypie von Na2PdF6 mit Na2SiF6 wird bestätigt.
    Additional Material: 2 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 364 (1969), S. 253-262 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Newly prepared Na3NiF6 of violett-blue colour is monoclinic [a = 5.44; b = 5.67; c = 7.85 Å; β = 90.1°] and isotypic with cryolite as well as Na3CoF6 [a = 5.49; b = 5.71; c = 7.90 Å; β = 90.1°] and Na3FeF6 [a = 5.52; b = 5.73; c = 7.95 Å; β = 90.4°]. Na3NiF6 does not obey the Curie-Weiss Law; the dependence of the effective magnetic moments on temperature indicates an equilibrium between low-spin and high-spin form.
    Notes: Neu dargestellt wurde violettblaues Na3NiF6. das monoklin [a = 5,44; b = 5,67; c = 7,85 Å; β = 90,1°] im Kryolith-Typ kristallisiert, zu dem auch Na3CoF6 [a = 5,49; b = 5,71; c = 7,90 Å; β = 90,1°] und Na3FeF6 [a = 5,52; b = 5,73; c = 7,95 Å; β = 90,4°] gehören. Na3NiF6 befolgt das Curie-Weisssche Gesetzt nicht; die Temperaturabhängigkeit der effektiven magnetischen Momente weist auf ein Gleichgewicht zwischen low-spin- und high-spin-Form hin.
    Additional Material: 1 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 67 (1995), S. 120-120 
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 105 (1922), S. 31-38 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1. Die Versuche, einen zu Cleves [Pt(NH3)2,(C6H5NH2) ]SO4 isomeren Komplex, ausgehend von einem tr-[Pt(NH3)2X2], darzustellen, schlugen fehl, führten jedoch zum tr-[Pt(C6H5NH2)2J2],dessen Konstitution durch Gegenüberstellen mit cis-[Pt(C6H5NH2)2J2] aus Synthese und chemischen Verhalten beider gegenüber Pyridin und Äthylendiamin festgelegt wurde. Außerdem wurde das [PtenJ2] dargestellt und [Pten2]J2 auf fünf verschiedenen Wegen erreicht.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 18 (1905), S. 1936-1941 
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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