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  • 1975-1979  (9)
  • 1970-1974  (5)
  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 24 (1977), S. 215-222 
    ISSN: 1432-0827
    Keywords: Mineralization ; Osteodentin ; Intracellular ; Ultrastructure ; Microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Newly formed osteodentin obtained from the anterior extremities of fetal or young rat incisors was observed by means of electron microscopy and electron probe X-ray microanalysis. Cells related to osteodentin formation frequently showed membrane bound intracellular bodies containing varying amounts of fine, needle-shaped crystals, which were identified as apatite. The intracellular clusters of apatite crystals were extruded from the cells through membrane fusion or cellular degeneration. These extracellular clusters seemed to be gradually incorporated into the mineralizing collagenous matrix, which developed around them. Frequent occurrence of dense, dotshaped or filamentous profiles suggested that the dense bodies seen in the perinuclear regions or in the Golgi area were the sites of crystal formation. Energy dispersive X-ray point analysis showed that the intracellular or extracellular apatite clusters contained sulfur in a concentration higher than was present in the mineralizing collagenous matrix. Furthermore, wave dispersive X-ray line analysis showed that the concentration of sulfur was higher in the osteodentin matrix than in the dentin matrix. The sulfur detected is presumed to be contained in acid mucopolysaccharides, which were distributed more heavily in the osteodentin matrix than in the dentin matrix. On the basis of these data, it was concluded that the unique chemical and structural characteristics of the osteodentin result primarily from the incorporation of apatite clusters of intracellular origin and associated acid mucopolysaccharides.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Flow, turbulence and combustion 27 (1973), S. 451-462 
    ISSN: 1573-1987
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In linear isotropic elasticity, cases exist where pure shear waves are possible even in bounded media; these have a nondispersive mode with propagation speed equal to that in an infinite medium. For these cases, consideration of a two-layer medium shows the existence of dispersion which vanishes only with equality of the propagation speeds. The present study uses the method of asymptotic expansions; a uniformly valid approximation is obtained to describe the speed and dispersive nature of these waves. The elegance of this approach is brought out by derivation of the basic result of this study viz., Jeffrey equation to describe the farfield structure of these waves.
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 20 (1974), S. 306-310 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A thermal continuous parametric pump for separating multicomponent mixtures was experimentally investigated using the model system tolueneaniline-n-heptane on silica gel adsorbent. A simple method for predicting separations is presented and is found to be in good agreement with the experimental results. The method, based on an equilibrium theory, invokes the assumption that a multicomponent mixture contains a series of pseudo binary systems. Each binary system consists of one of the solutes as one component and the common inert solvent as the other component.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Microchimica acta 58 (1970), S. 207-213 
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Unterwirft man Butyllävulinat in wäßrigem oder alkoholischem Milieu der reduktiven Aminierung, so entstehen unter anderemγ-Valerolactam undγ-Valerolacton. Diese wurden nach weitgehender Entfernung der flüchtigen Anteile (Ammoniak, Wasser oder Alkohol) durch isotherme Gaschromatographie unter Verwendung von Phenyläther oder Isoamylsalicylat als interne Standards bestimmt. Mit einem Wärmeleitfähigkeitsdetektor wurde eine 2 m lange Säule mit 6 mm i. D. aus Kupferrohr mit einer Füllung aus 25% Glykoladipat und Chromosorb W verwendet, mit Wasserstoff als Trägergas. Die Genauigkeit betrug ± 0,4% fürγ-Valerolacton und ± 0,5% fürγ-Valerolactam. Wurde hingegen ein Ionisierungsdetektor mit Wasserstoff-Flamme verwendet, so diente eine 2 m lange Säule mit 3 mm i. D. aus rostfreiem Stahl mit einer Füllung aus 10% Glykoladipat und Chromosorb W und Stickstoff als Trägergas. Die Genauigkeit betrug dann ± 0,5 bzw. ± 1,8%.
    Notes: Summary Theγ-valerolactam andγ-valerolactone in the reductive amination products of butyl levulinate in water or alcoholic medium, after removing most of the light fractions, ammonia, and water or alcohol, have been determined by isothermal gas chromatography using phenylether or isoamyl salicylate as the internal standard. With the thermal conductivity detector, a column of 6 mm I. D., 2 m long copper tubing packed with 25% glycol adipate/chromosorb-W was used, with hydrogen as the carrier gas. The accuracy was ± 0.4% forγ-valerolactone and ± 0.5% forγ-valerolactam. Using the hydrogen flame ionization detector, a column of 3 mm I. D., 2 m long stainless steel tubing packed with 10% glycol adipate/chromosorb-W was used, with nitrogen as the carrier gas; the accuracies forγ-valerolactone andγ-valerolactam were ± 0.5% and ± 0.8% respectively.
    Type of Medium: Electronic Resource
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