Die Lumineszenz,Verfärbung und Exoelektronenemission von Nach Verschiedenen Arten Gefärbten Ca2F-Kristallen

Zusammenfassung Anführung der Ergebnisse eines komplexen Studiums einiger optischer und elektrischer Erscheinungen bei natürlichen und künstlichen Kristallen von CaF₂ verschiedener Herkunft, die photochemisch, additiv oder gleichzeitig auf beide Arten (kombiniert) gefärbt waren. Untersucht wurden vor allem die Absorption bei konstanter und gleichmäßig ansteigender Temperatur (Thermoabsorption), die integrale Lumineszenz und deren Spektralanalyse und die Exoelektronenemission.Auszug aus einem Artikel, der in tschechischem Wortlaut in der Zeitschr. s. as. Fys.8 (1958) veröffentlicht wurde.     

Electronic processes andZ centres in NaCl and KC1 crystals

The paper gives the experimental results of the team-work study of coloured pure and Ca doped NaCl and KC1 crystals. The mechanism of the formation ofR centres by coagulation ofF centres and of the formation ofZ centres fromF centres, cation vacancies and Ca ions is discussed. An alternative model forZ ₃ centres is proposed. The possible connections between physical and chemical behaviour are indicated.

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Z- NaCl 1

NaCl KCl . R- F- Z- F-, Ca. Z ₃-. .

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This work was presented by the courtesy of Prof. R. Maurer at the Symposium on Color Centers, Corvallis, Oregon (1959).

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The authors wish to express their gratitude to K. Suk, K. Listoová and M. Javrková for carefully carrying out the measurements and I. Kunzlová and L. Nováková for preparing the crystals.     

Zur Frage der Pb(II)-Komplexe in den Alkalibromiden

Zusammenfassung Mittels der polarographischen Methode wurden die Bildungskonstanten der Bleibromokomplexe in Kaliumbromidlösungen berechnet, wobei als höchster der Komplex mit sechs Bromionen ermittelt wurde. Die gemessenen Absorptionsbanden von Blei in verschieden konzentrierten Kaliumbromidlösungen wurden den einzelnen Komplextypen zugeordnet.Auf Grund des Vergleiches des Absorptionsspektrums der mit Blei dotierten Alkali-bromidkristalle und der genügend konzentrierten analogen Lösungen ist man zur Ansicht gelangt, daß in Kristallen die die Gitterstelle des Alkaliions besetzenden zweiwertigen Bleiionen mit sechs benachbarten Bromionen als Liganden einen oktaedrischen Komplex bilden, analog wie dies bei Alkalichloridkristallen der Fall ist.

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On the problem of lead (II) complexes in alkaline bromides

The polarographic method was used to determine the stability constants of complexes of bivalent lead with bromide ions. The absorption bands of lead, measured in solutions of potassium bromide of varying concentration, were ascribed to these complexes. The agreement of the absorption bands of KBr crystals doped with lead and of analogical sufficiently concentrated solutions shows that in alkali bromide crystals lead is bound in the octahedral complex with six neighbouring bromine ions.

     

Die Röntgenolumineszenz von NaCl-Kristallen mit Kobalt

Ohne Zusammenfassung

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NaCl

     

Zur Bestimmung des Kaliums als Kaliumplatinchlorid

Ohne Zusammenfassung     

Thiosugars--derivatization agents for chiral resolution of homoleucines

o-Phthaldialdehyde was used in combination with a series of six thiosugars for the pre-column chiral derivatization of selected primary amino acids. The diastereomers were resolved on a conventional reversed-phase column and with fluorescence detection. A surprisingly effective resolution of 1-isoindolyl-(1-thioglycosides) derived from 1-thio-beta-L-fucose was observed.     

Estrogen-induced cholestasis results in a dramatic increase of b-series gangliosides in the rat liver

Hepatic ganglioside composition was investigated in normal and cholestatic Wistar rats. Cholestasis was induced by 17alpha-ethinylestradiol (EE; 5 mg/kg body weight s.c. for 18 days). As compared with controls, the EE administration resulted in severe cholestasis, as indicated by biochemical as well as morphological signs. Gangliosides isolated from the liver tissue were separated by TLC, with resorcinol-HCl detection and densitometric evaluation. As compared with controls, the total hepatic lipid sialic acid content in cholestatic rats was increased almost 2-fold (44.3 +/- 15.2 vs 79.1 +/- 9.0 nmol/g wet weight of liver tissue, p < 0.01). This increase was primarily due to the increase of ganglioside GD1a (3.6 +/- 1.0 vs 11.8 +/- 3.0 nmol/g wet weight of liver tissue, p = 0.001), as well as to the enormous up-regulation of b-series gangliosides GD3 (0.08 +/- 0.03 vs 2.0 +/- 1.2 nmol/g wet weight of liver tissue, p = 0.002), GD1b (0.1 +/- 0.06 vs 5.4 +/- 1.6 nmol/g wet weight of liver tissue, p = 0.002) and GT1b (0.06 +/- 0.03 vs 6.4 +/- 2.6 nmol/g wet weight of liver tissue, p = 0.002). As the majority of gangliosides are concentrated in cell membranes, our findings suggest that dramatic increase of b-series gangliosides might contribute to the protection of hepatocytes against the deleterious effects of cholestasis.     

Modification of the omega-meson lifetime in nuclear matter

Information on hadron properties in the nuclear medium has been derived from the photoproduction of omega mesons on the nuclei C, Ca, Nb, and Pb using the Crystal Barrel/TAPS detector at the ELSA tagged photon facility in Bonn. The dependence of the omega-meson cross section on the nuclear mass number has been compared with three different types of models: a Glauber analysis, a Boltzmann-Uehling-Uhlenbeck analysis of the Giessen theory group, and a calculation by the Valencia theory group. In all three cases, the inelastic omega width is found to be 130-150 MeV/c(2) at normal nuclear matter density for an average 3-momentum of 1.1 GeV/c. In the rest frame of the omega meson, this inelastic omega width corresponds to a reduction of the omega lifetime by a factor approximately 30. For the first time, the momentum dependent omegaN cross section has been extracted from the experiment and is in the range of 70 mb.