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  • Organic Chemistry  (19)
  • Polymer and Materials Science  (15)
  • Capillary  (1)
  • Superfluidity and superconductivity
  • 1970-1974  (35)
  • 1
    Electronic Resource
    Electronic Resource
    The formation of capillary basement membranes during internal vascularization of the rat's cerebral cortex (1972)
    Springer
    Cell & tissue research 133 (1972), S. 231-248 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00307145
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  • 2
    Electronic Resource
    Electronic Resource
    An electron microscopic method for studying nucleic acid-protein complexes. Visualization of RNA polymerase bound to the DNA of bacteriophages T7 and T3Dedicated to the memory of Dr. Jean-Pierre Tranzer. (1974)
    New York : Wiley-Blackwell
    Biopolymers 13 (1974), S. 995-1009 
    Details
    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
    URL: http://dx.doi.org/10.1002/bip.1974.360130514
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  • 3
    Electronic Resource
    Electronic Resource
    Determination of thermodynamic parameters of polymer-solvent systems from sedimentation-diffusion equilibrium in the ultracentrifugePresented in part at the Microsymposium on Macromolecules, “Polymer Gels and Concentrated Solutions,” Prague, September 1967. (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 841-868 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Sedimentation equilibrium in the ultracentrifuge means that there is such a distribution of molecular species throughout the cell, that the centrifugal forces are balanced by differences in the activities. This provides a method for determination of the activities and the chemical potentials in polymer solutions which, in principle, is very simple and reliable. A complication is caused by polydispersity of the dissolved polymer. If one assumes that the interaction parameter depends on concentration and temperature, but not on molecular weight, it is possible to determine the chemical potential of polymer and solvent from the ultracentrifugal data. Experiments have been carried out on the systems polystyrene-toluene and polystyrene-cyclohexane at different temperatures and in the concentration range 0-80 wt-%. The results are expressed in the data for the chemical potential of the solvent, the number average chemical potential of the polymer and the interaction parameter χ.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1970.160080603
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  • 4
    Electronic Resource
    Electronic Resource
    Wärmealterung und Grenztemperatur von organischen Isolierstoffen (1971)
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 2 (1971), S. 127-135 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mawe.19710020304
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  • 5
    Electronic Resource
    Electronic Resource
    Erfahrungen mit Schutzbeschichtungen an Stahlwasserbauten der Wasser- und Schiffahrtsverwaltung im Bereich der Nord- und Ostsee (1972)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 23 (1972), S. 993-1002 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19720231106
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  • 6
    Electronic Resource
    Electronic Resource
    Hauchvergoldung auf RelaiskontaktenKurzfassung einer Podiumsdiskussion vom 3. 10. 1973, veranstaltet von der Fachgruppe 1.6 „Kontaktverhalten und Schalten“ an der TU-Karlsruhe (1974)
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 5 (1974), S. 290-297 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mawe.19740050603
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  • 7
    Electronic Resource
    Electronic Resource
    Synthese und eigenschaften molekulareinheitlicher n-paraffine bis zum C140H282 (1972)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 162 (1972), S. 63-79 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1972.021620107
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  • 8
    Electronic Resource
    Electronic Resource
    Thermodynamic parameters of polymer-solvent systems from light-scattering measurements below the theta temperature (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 9 (1971), S. 1553-1577 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: As is well known, the chemical potentials of polymer and solvent in solution and, hence, the Flory-Huggins interaction parameter χ can be determined from scattered light intensities from dilute and concentrated solutions of the polymer in the solvent concerned. Preferably, measurements should be performed at temperatures as low as possible, provided the temperature exceeds the cloudpoint for the concentration used. It is shown that the lower the temperature and, consequently the higher the scattered light intensity, the better is the accuracy of the parameters obtained. At each temperature the scattered light intensity shows a maximum at some concentration. Below the theta temperature the ratio of scattered light intensity and concentrations also shows a maximum at some concentration. The values and the concentrations of these maxima for various temperatures enable the maximum of the spinodal to be determined. The spinodal itself can be determined by an extrapolation procedure of the reciprocal scattered light intensities. Measurements have been performed with three narrow-distribution polystyrene samples in cyclohexane. On the basis of the results, χ, and its dependence on concentration, temperature, and molecular weight can be determined to high accuracy.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.160090902
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  • 9
    Electronic Resource
    Electronic Resource
    Relation between the refractive index increment and the density increment of binary mixtures: Application to the determination of partial specific volumes of polymers in solution (1972)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 519-526 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Starting from the Lorentz-Lorenz equation, Heller, a few years ago, advanced a method for calculating the partial specific volume of a substance in a dilute solution from the refractive index increment of the solution and the specific refraction of the solute. It is shown that this method, based on graphical extrapolation, can be considerably simplified. Further, a method is indicated by which the partial specific volume of a substance over the whole range of concentrations can be calculated in an analogous manner. The method is checked and elucidated with reference to some experimental examples.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1972.160100308
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  • 10
    Electronic Resource
    Electronic Resource
    Experimental thermodynamics of the helix-random coil transition. III. Determination of the transition enthalpies of the helical complexes poly(I + C) and poly I in solution (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 923-936 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The enthalpies of the helix-coil transitions of the ordered polynucleotide systems of poly(inosinic acid)-poly(cytidylic acid) [poly(I + C)], (helical duplex), and of poly (inosinic acid) [poly(I + I + I)], (proposed secondary structure: a triple-stranded helical complex), were determined by using an adiabatic twin-vessel differential calorimeter. Measuring the temperature course of the heat capacity of the aqueous polymer solutions, the enthalpy values for the dissociation of the helical duplex poly (I + C) and the three-stranded helical complex poly(I + 1 + 1), respectively, were obtained by evaluating the additional heat capacity involved in the conformational change of the polynucleotide system in the transition range. The ΔH values of the helix-coil transition of poly (I + C) resulting from the analysis of the calorimetric measurements vary between the limits 6.5 ± 0.4 kcal/mole (I + C) and 8.4 ± 0.4 kcal/mole (I + C). depending on the variation of the cation concentration ranging from 0.063 mole cations kg H2O to 1.003 mole cations/kg H2O. The calorimetric investigation of an aqueous poly I solution (cation concentration 1.0 mole/kg H2O) yielded the enthalpy value ΔH = 1.9 ± 0.4 kcal/mole (I), a result which has been interpreted qualitatively following current models of inter- and intramolecular forces of biologically significant macromolecules. Additional information on the transition behavior of poly(I+ C)Was obtained by ultraviolet and infrared absorption measurements.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360090806
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