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  • Chemistry  (82)
  • Inorganic Chemistry  (12)
  • Basement membrane  (1)
  • Magnetism
  • 1970-1974  (83)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 133 (1972), S. 231-248 
    ISSN: 1432-0878
    Keywords: Ontogenesis ; Capillary ; Basement membrane ; Cerebral cortex (Rat.) ; Light- and Electromicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The vascularization of the parietal-temporal region of the cerebral hemispheres has been studied in a total of 50 rats from day 11 of gestation up to adults. The first extracerebral vessels constituting the primary perineural vascular network and the first intracerebral vessels on day 12–14 of gestation show sinusoid characteristics, i.e. irregular thickness of the endothelial wall perforated by fenestrations or small holes and showing, if at all, the beginning accumulation of basement membrane (BM) material. No paired vessels have been observed which would be expected if internal vascularization of cortical anlage starts by penetrating loops. Immature capillaries developing by sprouting (and) from the preexistent vessels begin to appear at about day 15 of gestation. The further differentiation of the terminal vascular bed and the establishing of the definitive architecture is accompanied by the maturation of cortical tissue, i.e. diminution of extracellular spaces, differentiation of perivascular, astroglial and neuronal elements including the development of synapses. The continuous process of BM-formation from the first appearance until the postnatal thickening is described by four successive stages: Stage 1. Local accumulations of fine filamentous material between endothelium and opposite perivascular surfaces of sinusoids and sprouts. Stage 2. Delicate networks of filaments attached on endothelial, pericytal and adjacent glial plasma membranes (PM) of immature capillaries, plaques of lamina densa in narrow perivascular clefts. Stage 3. A thin continuous lamina densa adapted to the PM; its filaments are arranged parallel to the cell surface. In this plane they run randomly. In the lamina rara only few filaments run to the PM mainly perpendicular: stage of immature cortical capillaries. Stage 4. Thickened lamina densa, condensed filamentous pattern; narrow zone of lamina rara: stage of mature cortical capillaries. Coincidental with the rapid thickening of BM in the 3rd–4th postnatal week the characteristics of capillary growth change: The intensive sprouting is finished and the capillary length increases nearly proportionally to tissue volume later on. It is suggested that the BM plays a role in regulating differentiation and mitotic division of the adjacent cells.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Double-stranded DNA can be readily adsorbed on mica or directly on carbon coated grids from the surface of solutions containing ethidium bromide, actinomine, or propidium diiodide. The DNA molecules are unfolded, well separated, and show a length distribution similar to molecules prepared by protein monolayer techniques.Since the intercalating dyes tested do not lead to an increased apparent diameter of the nucleic acid the method is useful for the study of nucleic acid-protein complexes. As a model, the binding of E. coli RNA polymerase to phage T7 and T3 DNA was examined under different conditions. The enzyme can easily be identified and its position along the DNA molecule can be mapped.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 5 (1971), S. 65-77 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 19 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 3461-3462 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1891-1902 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation of [2.2]Paracyclophanes by Addition of Acetylene Derivatives to 1,2,4,5-HexatetraeneThe tetrasubstituted [2.2]paracyclophanes 4a - e are formed by cycloaddition of the symmetrical acetylene derivatives 2a - e to 1,2,4,5-hexatetraene (1), and their constitution and configuration is established by spectroscopic methods, degradation and pyrolysis experiments. The tetramethyl ester 4a is reduced to the tetraalcohol 4g, and the tetracarboxylic acid 4c is converted to the bisanhydride 4f and [2.2] paracyclophanes (4h), respectively. All possible disubstituted [2.2] paracyclophanes 6 are obtained when methyl propiolate (5a) is added to. 1, whereas further symmetrical and unsymmetrical acetylene derivatives do not react with 1.
    Notes: Die tetrasubstituierten [2.2]Paracyclophane 4a - e werden durch Cycloaddition der symmetrischen Acetylenderivate 2a - e an 1,2,4,5-Hexatetraen (1) dargestellt und ihre Konstitution und Konfiguration durch spektroskopische Methoden. Abbau- und Pyrolyseversuche bewiesen. Der Tetramethylester 4a wird zum Tetraalkohol 4g reduziert und die Tetracarbonsäure 4c in das Bisanhydrid 4f bzw. [2.2] Paracyclophan (4h) übergeführt. Bei der Anlagerung von Propiolsäure-methylester (5a) an 1 werden alle isomeren disubstituierten [2.2]paracyclophanes 6 erhalten. Weitere symmetrische und unsymmetrische Acetylenderivate reagieren nicht mit 1.
    Additional Material: 3 Tab.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 2 (1971), S. 127-135 
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Thermal aging and endurance of organic insulating materials. The knowledge of the thermal endurance of organic insulating materials is very important for the application in electrical engineering. The change of the values of the properties by thermal aging is, theoretically, described under the assumption being a linear connection to the rules of the kinetic theory of chemical reactions. By this premise it is possible to indicate functions for aging and thermal endurance, being plotted as straight lines in suitable coordinates. In this way the test results can be evaluated better than by conventional means.
    Notes: Die Kenntnis der Grenztemperatur organischer Isolierstoffe ist für deren Anwendung in der Elektrotechnik von großer Wichtigkeit. Die Änderung von Eigenschaftswerten auf Grund einer Wärmebehandlung wird theoretisch beschrieben unter der Annahme, daß ein linearer Zusammenhang mit den Gesetzen der Reaktionskinetik besteht. Unter den getroffenen Voraussetzungen können. Alterungs- und Lebensdauerfunktionen angegeben werden, die sich bei geeigenten Koordinaten als Geradendarstellen lassen. Meßergebnisse können auf diese Weise besser ausgewertet werden als nach herkömmlichen Verfahren.
    Additional Material: 9 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 23 (1972), S. 993-1002 
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Experience gained with protective coating systems on steel underwater structures managed by Wasser- und Schifffahrtsverwaltung in the North Sea and Baltic Sea regionsIn order to develop protection systems for steel underwater structures in the coastal regions long-term exposure tests have been carried out at Kiel-Holtenau, Büsum and Brunsbüttelkoog (Germany); the tests included exposure to seawater and brackish water. On the basis of the results obtained it was possible to design coating systems having relatively long useful life. The behaviour ob these systems under practical application conditions is in agreement with the results obtained during the tests. On this basis it is possible to define requirements concerning in efficient coating: derusting to the blank metal;Zn dust primer; coating of tar modified epoxy resins having a minimum coating thickness of 500 μm; (multicoat systems on tar-epoxy basis are not satisfactory); thick coatings on polyurethane basis are promising for the future.
    Notes: Um Schutzmaßnahmen für Stahlwasserbauten im Küstenbereich zu entwickeln, wurden Langzeitversuche in Kiel-Holtenau und Büsum sowie Brunsbüttelkoog durchgeführt, wobei sowohl die Einwirkung von Meerwasser als auch die von Brackwasser untersucht wurde. Aufgrund der dabei erhaltenen Ergebnisse konnten neue Beschichtungssysteme mit verhältnismäßig langer Lebensdauer entwickelt werden. Das Verhalten der Systeme unter Praxisbedingungen entspricht den bei den Versuchen erhaltenen Ergebnissen. Auf dieser Grundlage lassen sich die an eine Beschichtung zu stellenden Anforderungen wie folgt definieren: Metallblanke Entrostung; evtl. Zn-Staubbeschichtung als Grundierung; Überzug auf Teerepoxidbasis mit mindestens 500 μm Schichtdicke (Mehrschichtenanstriche auf Teerepoxidbasis haben sich nicht bewährt); Dickschichtüberzüge auf Polyurethanbasis dürften sich in Zukunft durchsetzen.
    Additional Material: 12 Ill.
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  • 9
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Gold Flashing on Relay Contacts. It is not the colour but the resistance of contacts which determines their efficiency. Since, however, it is an expensive and time-wasting procedure to measure the resistance of every contact, many costomers reject relays whose silver contacts show a brownish-black discolouration, complaining that they have been kept too long in stock.This problem was believed to have been solved by the introduction of gold-flashing as a temporary coating while the contacts are kept in stock. Now the German Post Office's Telecommunications Head Quarters (Fernmeldetechnisches Zentralamt der Deutschen Bundespost) in Darmstadt have found indications which raise some suspecions as to the damaging side-effects of gold-flashing. For this reason, a working committee of the VDE (Association of German Electrical Engineers), group 1.6„Contact behaviour and switching processes“, undertook its own investigations. The results were revealed during a platform-discussion on the 3rd October, 1973 in the Technical College at Karlsruhe and are given here in the form of edited speeches and a summary of the discussion.
    Notes: Nicht die Farbe, sondern der Kontaktwiderstand ist ein eindeutiges Maß für die Brauchbarkeit von Kontakten. Da aber die Messung des Kontaktwiderstandes zeitraubend und teuer ist, weisen viele Kunden Relais mit braun-schwarz angelaufenen Silberkontakten als „überlagert“ zurück. Seit der Einführung der Hauchvergoldung als vorübergehender Lagerschutz galt dieses Problem als gelöst. Hinweise des Fernmeldetechnischen Zentralamtes der Deutschen Bundespost in Darmstadt haben Zweifel an der Unschädlichkeit der Hauchvergoldung aufkommen lassen und einen Arbeitskreis der VDE-Fachgruppe 1.6„Kontaktverhalten und Schalten“ zu eigenen Untersuchungen veranlaßt. Die Ergebnisse wurden in einer Podiumsdiskussion am 3. 10. 1973 an der Technischen Hochschule Karlsruhe vorgetragen und werden heir als Kurzfassung der Vorträge und Zusammenfassung der Diskussion wiedergegeben.
    Additional Material: 4 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 162 (1972), S. 63-79 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The reaction of α,ω-dihalogeno-alkanes with sodium and a consecutive catalytic hydrogenation results in a mixture of paraffins with a discontinuous distribution of molecular weight. Starting with 1.10-dibromodecane only paraffins with 10, 20, 30 etc. carbon atoms are obtained, whereas 1.20-dibromoeicosane produces a mixture of paraffins with 20, 40, 60 etc. carbon atoms. These mixtures of paraffins were separated by gel chromatography into monodisperse compounds. The highest molecular paraffine thus obtained was C140H282.With C70H142 as an example the temperature dependence of the small angle X-ray diffraction has been measured. From the intensity and position of the long period reflexion the variation of three structure parameters could be ascertained, suited for the characterization of the lamellar structure.
    Notes: Die Umsetzung von α,ω-Dihalogenalkanen mit Natrium führt nach anschließender katalytischer Hydrierung zu einem Paraffingemisch mit diskontinuierlicher Molekulargewichtsverteilung. So enthält das aus 1.10-Dibromdecan hergestellte Produkt nur Paraffine mit 10, 20, 30 usw. C-Atomen, ein aus 1.20-Dibromeicosan hergestelltes Produkt dagegen nur die Paraffine mit 20, 40, 60 usw. C-Atomen. Diese Paraffingemische wurden gelchromatographisch in die molekulareinheitlichen Verbindungen zerlegt und Paraffine bis C140H282 isoliert.Am Beispiel des C70H142 wurde die Temperaturabhängigkeit der Röntgenkleinwinkelstreuung gemessen. Aus Intensität und Lage der Langperiodenreflexe ließen sich die Änderungen von drei Strukturparametern ermitteln, die zur Charakterisierung der Lamellarstruktur geeignet sind.
    Additional Material: 9 Ill.
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