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  • 1975-1979  (26)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 107 (1976), S. 459-472 
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The syntheses and mass spectra of the four 3,17β-dihydroxyandrostane-11,16-diones and of the two 17β-hydroxyandrostane-3,11,16-triones are described. These compounds decompose in the mass spectrometer in a different way than androstanes containing a carbonyl group in the position 11 or 16: First they eliminate the C-atoms 15 to 17. Then a cleavage of the C-atoms of the ringA plus C-6 follows resulting in key ions which contain the ringC and the C-atom 7. The connection of theA/B-ring system can be deduced by the spectra for all described compounds. The unequivocal determination of the configuration of the 3-hydroxy group is possible only for the 3,17β-dihydroxy-5β-androstan-11,16-diones.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 11 (1976), S. 175-177 
    ISSN: 1432-0630
    Keywords: 82.50 ; 42.60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Trimethylamine and triethylamine are shown to luminesce at their wavelengths of fluorescence when excited by electrical discharge. When excited at low pressures or at high frequencies, a longer wavelength emission is observed at 380 nm. This emission, rather than being due to excimers which are known to exist for some tertiary aliphatic amines, is shown to be due to emission from a decomposition product. Lasing using electrical discharge pumping was attempted, but yielded negative results due to the rapid decomposition. Optical pumping might be successful however, and produce a tunable gas-phase ultraviolet laser
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Helgoland marine research 28 (1976), S. 250-303 
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung 1. Die Wachstumsphase der Oocyten vonLepidochitona cinereus L. läßt sich nach cytomorphologischen und histologischen Gesichtspunkten in fünf Entwicklungsstadien einteilen. 2. Typische Oogonien in den Ovarien adulter Weibchen sind nicht eindeutig nachzuweisen. Es ist noch kein kugeliger Nucleolus ausgebildet; der Kern ist teilweise dicht mit Chromatinkörpern angefüllt. Diese Eizellen sind noch nicht vollständig durch Follikelzellen getrennt. 3. Die Oocyten des Stadiums I sind stets von Follikelzellen umgeben. Ribosomenähnliche Grana akkumulieren sich zum kugeligen Nucleolus oder sind auf dem Wege zur Emission durch die Kernhülle. Sie bilden einen osmiophilen juxtanucleären Saum. Das Oocytoplasma enthält wenige kleine Mitochondrien, einen kleinen Golgi-Apparat, einige Lipidschollen und einzelne Stränge des Endoplasmatischen Retikulums. 4. Charakteristisch für das Stadium II sind 1 bis 2 Dotterkerne (Balbiani-Körper), die sich aus einer dichten Wolke von Ribosomen und einer Schale aus Mitochondrien zusammensetzen. Der Nucleolus tritt in eine aktive Phase, zoniert sich in ein vakuoläres Zentrum und einen homogenen Cortex und schnürt von nun an Nucleolargrana (Paranucleoli) ab. 5. Die vitellogenetische Phase wird im Entwicklungsstadium III durch die Vakuolisierung des Cytoplasma eingeleitet. Es können drei Vakuolentypen unterschieden werden, die ihren Ursprung entweder im Grundcytoplasma selbst, in Vesikeln des ER oder in benachbarten Golgi-Feldern haben können. Das ER entwickelt sich zu konzentrischen Membranstapeln. 6. Das Stadium IV ist gekennzeichnet durch cytoplasmatische Aufwölbungen mit gleichzeitigen Einsenkungen der Oocytenmembran, die auf die Tätigkeit des oocytären Follikelepithels zurückzuführen sind. Es werden möglicherweise drei Wege der Dottersynthese beschritten: (a) In der inneren Mitochondrienmatrix akkumulieren sich Substanzen, die zu Protein-Primordialdotter mit Myelinlamellen führen. (b) Pinocytotische Vesikeln beteiligen sich an der Genese von homogen strukturierten Eiweiß-Dotterkugeln. (c) Lipidschollen gehen aus cytoplasmatischen Vakuolen hervor, die mit den umfangreichen Stapeln der annulate lamellae in Verbindung gestanden haben. Beim Übergang zum Stadium IV scheidet hauptsächlich die Oocyte über Mikrovilli eine aus Mucopolysacchariden bestehende dreischichtige, kompliziert gebaute Oocytenhülle ab. Im Cytoplasma liegen rootlets, die im Aufbau Cilienwurzeln gleichen. 7. Im Stadium V erscheinen im cortikalen Cytoplasma Rindenvakuolen. Die Kernhülle faltet sich; die Nucleoli zerfallen. Die ausgereiften Protein-Dotterpartikeln enthalten ein homogenes Internum mit aufgelagertem parakristallin strukturiertem Cortex. Durch Anlagerung von Vesikeln und Lipidkörpern entsteht schließlich typischer Lipoproteindotter. Die Eizelle gibt eine weitere primäre Oocytenhülle, die Dottermembran ab.
    Notes: Abstract Oocyte development ofLepidochitona cinereus L. has been examined by electron microscope with special regard to ultrastructural changes during vitellogenesis. Oogenesis can be subdivided into five stages based on cytological and histochemical features. Typical oogonia have not been found; only early oocytes of the meiotic prophase with an incomplete nucleolus are situated on the basallamina of the gonadal wall. The single nucleolus is formed in stage I; osmiophilic nucleolar granules pass through the nuclear envelope. Stage II — oocytes are characterized by simple Balbiani-bodies or yolk nuclei, which consist of ribosomes and a hull of mitochondria. The formerly homogenous nucleolus disintegrates into caryoplasmic vacuoles and produces paranucleoli. In the previtellogenetic stage III the yolk nuclei are reduced and large systems of endoplasmic reticula — arranged concentrically or flattened — and voluminous cytoplasmic vacuoles appear. Three types of vacuolar complexes can be observed: Complete membrane bounded vacuoles with a filaceous content built up by Golgi dictyosomes, vacuoles with remains of membranes which seem to originate from endoplasmic cisternae and vacuolar spaces lying free in the cytoplasm. The vacuoles contain either acid mucopolysaccharides or acid lipids. The actual vitellogenesis starts in stage IV after depression of the oocyte membrane to ooplasmic bumbs by the perioocytal follicle epithelium. Extensive piles of annulate lamellae contact the cytoplasmic vacuolar bodies. Striated long rootlets branch off microtubules at their terminal end in the direction of the oocyte membrane below the oocyte hull. Microvilli secrete mucopolysaccharides into the intercellular space between oocyte membrane and inner follicle cell membrane. The resulting eight cup-like hull processes are composed of three layers. Possibly there are three ways of forming vitelline bodies: (a) transforming mitochondria and multivesicular bodies lead to protein yolk; (b) mitochondria connect with cytoplasmic vacuoles and probably participate in genesis of lipid yolk; (c) microvesicles become protein yolk precursors. The lipoprotein yolk spheres consist of a homogenous internum and a paracrystalline structured cortex. Lipid yolk accumulates at the periphery of the cytoplasmic vacuoles, which degenerate later. The mature oocyte secretes another primary oocyte envelope, the vitelline membrane, shortly before spawning. Cortical granules appear below the oocyte membrane.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 11 (1976), S. 2075-2081 
    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 The composition triangle of the Ni-Mo-Al ternary system contains a monovariant trough between theγ′ (Ni3Al)-α(Mo) pseudobinary eutectic and a guessedγ(Ni)-γ′ (Ni3Al)-α(Mo) ternary eutectic. Alloys with compositions on this trough were directionally solidified at various growth rates. The microstructure of the alloys consists of fine Mo fibres of rectangular cross-section in an Ni3Al/Ni matrix. The determined crystallographic relationship does not correspond to an interface of low lattice mismatch. The eutectic trough strongly extends towards increasing Mo contents so that the volume fraction of the Mo fibres varies between 18 and 25% dependent on composition. It was not possible to determine the position of a ternary eutecticγ-γ′-α because the liquidus temperatures along the trough are almost equal and the distribution of the three phases is strongly dependent on the growth rate.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 11 (1976), S. 2075-2081 
    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 The composition triangle of the Ni-Mo-Al ternary system contains a monovariant trough between theγ′ (Ni3Al)-α(Mo) pseudobinary eutectic and a guessedγ(Ni)-γ′ (Ni3Al)-α(Mo) ternary eutectic. Alloys with compositions on this trough were directionally solidified at various growth rates. The microstructure of the alloys consists of fine Mo fibres of rectangular cross-section in an Ni3Al/Ni matrix. The determined crystallographic relationship does not correspond to an interface of low lattice mismatch. The eutectic trough strongly extends towards increasing Mo contents so that the volume fraction of the Mo fibres varies between 18 and 25% dependent on composition. It was not possible to determine the position of a ternary eutecticγ-γ′-α because the liquidus temperatures along the trough are almost equal and the distribution of the three phases is strongly dependent on the growth rate.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 48 (1976), S. 21-26 
    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
    Notes: Bei der Kohle- und Erzaufbereitung durch Flotation wird wegen der abzuscheidenden spezifisch schwereren Teilchen mit groben Luftblasen gearbeitet, die mittels Filterböden, Begasungsrührern o. ä. erzeugt werden. Im Gegensatz hierzu werden in der Abwassertechnik wegen der geringen Größe und des geringen Gewichtes der zu entfernenden schwer- oder nicht absetzbaren Stoffe sowie des häufig hydrophilen Charakters dieser Stoffe nur Flotationsverfahren mit kleinsten Luftblasen eingesetzt. Zur Erzeugung feinster Luftblasen findet überwiegend das Überdruck-Flotationsverfahren Anwendung. Die Erzeugung sehr feiner Gasblasen durch Elektrolyse oder mit Hilfe spezieller Begasungsrührer ist ebenfalls möglich. Es werden die Grundlagen der Überdruck-Flotation, konstruktive Gestaltungsmöglichkeiten, Anwendungsfälle und Bemessungsgrundlagen sowie Wirtschaftlichkeitsfragen behandelt. Das Flotationsverfahren gehört heute zu den erprobten unit operations der Abwasser-Technik.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 443 (1978), S. 5-10 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: An Eight-membered Ring System Made of Phosphorus, Nitrogen, and OxygenThe synthesis of the cyclic anhydride of imido dimethylphosphinic ethylphosphoric acid is described. The compound is characterized by its n.m.r. and mass spectra.
    Notes: Die Synthese des cyclischen Anhydrids der Imido-dimethylphosphinsäure-äthylphosphorsäure wird beschrieben. Die Verbindung wird durch ihre NMR- und Massenspektren charakterisiert.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Publication Date: 1976-11-01
    Print ISSN: 0022-2461
    Electronic ISSN: 1573-4803
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Published by Springer
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  • 9
    Publication Date: 1976-10-01
    Print ISSN: 0340-3793
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Published by Springer
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  • 10
    Publication Date: 1975-09-01
    Print ISSN: 0015-7899
    Electronic ISSN: 1434-0860
    Topics: Technology
    Published by Springer
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