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  • 2020-2022
  • 1985-1989
  • 1970-1974  (2)
  • 1965-1969  (3)
  • 1973  (2)
  • 1965  (3)
  • Phosphorus
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 12 (1973), S. 259-279 
    ISSN: 1432-0827
    Keywords: Osteocyte ; Calvarium ; Histology ; Development ; Calcium ; Phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des cartes tissulaires ainsi que les caractéristiques et propriétés cellularires ont été relevées au cours d'une étude de microscopie optique du développement de la calotte cranienne de souris, avant la naissance, jusqu'au 26ème jour. Les population d'ostéocytes de moitiés droite et gauche de ces calottes sont semblables, mais décroissent avec le temps dans un volume donné. De petites plages limitées de matrice osseuse se colorent pour le phosphate (ou carbonate) de façon plus nette que la matrice environnante, qui se colore légèrement après coupe. Les divers types ostéocytaires se distinguent par les réactions histochimiques du calcium et du phosphate, qui sont associés dans les cellules osseuses de façon complexe, variant dans le temps et la localisation. Ces deux constituants ne sont pas toujours présent dans les cellules des diverses régions, ou dans la même localisation dans un type cellulaire donné. En tenant compte des changements visible dans les divers types cellulaires avec le temps, dans des régions données, une hypothèse de “charge” et “décharge” cellulaire est émise.
    Abstract: Zusammenfassung Anläßlich einer mikroskopischen Studie über die Entwicklung des Mäuse-Calvariums von der Pränatalperiode bis zu 26 Tagen nach der Geburt wurden auch die Gewebetopographie sowie die Charakteristica und Eigenschaften der Zellen aufgezeichnet. Die Osteocyten-populationen in der linken und rechten Hälfte des Calvariums waren sich gleich, nahmen jedoch bei einem gegebenen Volumen mit der Zeit ab. Kleine isolierte Stellen von Knochen-matrix konnten leichter auf Ph sphat (oder Carbonat) angefärbt werden, als die umgebende Matrix, welche sich wohl am Schnitt, nicht aber am ganzen Stück färben ließ. Die verschiedenen Typen von Osteocyten wurden aufgrund histochemischer Calcium- und Phosphat-reaktionen bestimmt. Calcium und Phosphat waren innerhalb der Knochenzellen auf komplexe Art miteinander verbunden, die je nach Zeit und Lagerung unterschiedlich war. Zellen in abgetrennten Bereichen enthielten nicht immer Calcium und Phosphat und beide waren bei einer bestimmten Zellenart auch nicht immer am gleichen Ort abgelagert. Aufgrund der an ausgewählten Stellen beobachteten, zeitlich bedingten Veränderungen innerhalb der verschiedenen Zelltypen wird vorgeschlagen, daß es sich dabei um eine Sequenz von “Ladung” und “Entladung” der Zellen handelt.
    Notes: Abstract Tissue maps, and cell characteristics and properties were recorded in a study under the optical microscope of the development of the mouse calvarium from pre-natal to 26 days. Osteocyte populations in left and right halves of the calvarium were similar, but decreased with time for a given volume. Small isolated areas of bone matrix stained for phosphate (or carbonate) in a more readily available form from that in the surrounding matrix, which could be stained after sectioning but failed to stain in bulk. Osteocyte types were defined on the basis of histochemical methods for calcium and phosphate, which were associated inside bone cells in a complex manner, varying with time and position. The calcium and phosphate were not always present within the cell in discrete regions and were not always present in the same place in a given cell type. On the basis of a study of changes in cell types with time in selected sites a sequence of “loading” and “unloading” is proposed.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0570-0833
    Keywords: Displacement reactions ; Phosphorus ; Phosphorus ; Reaction mechanisms ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of phosphorus(v) compounds involving the mutual interconversion of tetra- and pentacoordinate species are discussed in a critical review emphasizing stereochemical implications of the reaction mechanism. This discussion includes the formation and decomposition of the stable oxyphosphoranes, the Michaelis-Arbusov, Perkov, and Wittig reactions, interconversions of phosphines and their oxides, and the nucleophilic displacements on phosphonium compounds. Reactions of phosphate esters and related compounds receive particular attention. All chemical arguments are derived by considering the effect of factors determining the relative stabilities of phosphorane derivatives, their rates of formation, decomposition and rearrangement by bond deformation or rupture and recombination processes, considerations which are uniformly applied on the basis of concepts developed in a preceding communication[2]. It is shown that a comprehensive mechanistic interpretation of the foregoing reactions requires substantial addition to available conceptual foundations such that, in many cases, present concepts and mechanisms must be revised.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 457-471 
    ISSN: 0570-0833
    Keywords: Color ; Azo compounds ; Azobisphosphoric acid ; Phosphorus ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Attempts to explain the surprising violet color of the new azobisphosphonic acid derivatives Y2OP—N=N—POY2 have led to the preparation and spectroscopic characterization of more than 60 azo compounds. The long-wavelength n → π* transitions on which the color depends exhibit regularities which justify the assumption of substitutent-specific absorption increments. The complex relation between color and constitution of azo compounds can be qualitatively explained with the aid of orbital models. Infrared and ultraviolet spectral data show that conjugation is inhibited by tetra-coordinated phosphorus (V). the π-system of these compounds therfore comprises only for atoms, P·N·N·P. The unexpected violet color of the phosphorus azo compounds can be ascribed to a π*/d orbital interaction. The substituent effects described have general significance, and n→π*transitions of other chromophores are similarly affected.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 1023-1038 
    ISSN: 0570-0833
    Keywords: Heterocycles ; Phosphorus ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation of heterocycles containing phosphorus is described. The chemical behavior of ring systems containing trivalent phosphorus is mainly determined by their phosphine character; heterocyclic behavior in the ordinary sense is shown by rings containing functional groups. Syntheses and reactions of cyclic compounds of pentavalent and hexavalent phosphorus are particularly interesting.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 4 (1965), S. 1007-1013 
    ISSN: 0570-0833
    Keywords: Sulfur ; Selenium ; Tellurium ; Phosphorus ; Organometallic compounds ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bond fission of molecular sulfur, selenium, and tellurium by lithiotriphenylmetal compounds (of Ge, Sn, Pb) is summarized. The products are suitable as starting materials for synthesis of new “ether analogues”. Transphenylation with tetraphenylstannane is interpreted as a high-temperature variant of the usual fission of chalcogen molecules by nucleophilic reagents. In principle, transphenylation can be applied also to other elements, as is illustrated for phosphorus. In the syntheses achieved, many of the tin-phosphorus compounds arising as intermediates can be isolated.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
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