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  • 1975-1979  (1)
  • 1965-1969  (1)
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  • 1
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract K-, L andM-shell ionization cross sections have been measured for 23 elements, 12≦Z≦92, after bombardment with relativistic electrons, 15≦E 065MeV, by means of high resolution semiconductor detectors and a recently developed gas-scintillation proportional counter. For constant electron bombarding energyE 0 the ionization cross sections follow a power law dependence,σ∽Z −α, and forE 0=50MeV we deducedα =2.45±0.02 for theK shell andα=3.00 ±0.09 for theL shell. The observedZ dependence exhibits significant systematic deviations from theoretical predictions which exceed the experimental values up to 15 % at lowZ elements for theK shell and on the average about 11% for theL andM shell. The same behaviour of too low experimental values, i.e. an overestimation by the theory, is observed for the energy dependence of the cross sections for all shells. A scaling behaviour describing theZ andE 0 dependence for allK-, L andM-shell data points is observed which also predicts the experimental values by other groups at lower and higher energies correctly. The comparsion of the measuredLΒ/Lα, andLγ/Lα intensity ratios for highZ elements with the values obtained by other groups in the energy range 0.3≦E0≦1,000 MeV exhibits an increase with bombarding energy that cannot merely be explained by the energy dependence of the subshellionization cross sections for theL shell. An attempt to explain this effect with the change of the Coster-Kronig transition probability is described.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1435-702X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Serial examinations of rabbit eyes at different times following intravenous injections of a blastospore suspension of Candida albicans were performed. All histological findings in PAS stained slides demonstrate that the microorganisms reach the eye via the ciliary arteries and infection starts primarily in the choroid. Here the outpoured leukocytes are soon replaced by histocytic cell formations. The fungi break into the retina through Bruch's membrane followed by these inflammatory cells. In contrast to this there is a conspicuous absence of blastospores in and around the retinal vessels. The retina's lack of primary involvement is of great advantage to the function of the eye as the uvea has all defense mechanisms available to combat the invaders. Our results show that there are apparently particular ways of blood supply to the retinal circulation.
    Notes: Zusammenfassung An Hand von histologischen Befunden, die bei Serienuntersuchungen von Kaninchenaugen nach intravenöser Injektion von Candida albicans-Suspensionen zur Beobachtung kamen, konnte gezeigt werden, daß die Einschleusung der Keime über die Ciliararterien erfolgt und die Infektion primär in der Aderhaut beginnt. Hier bilden sich nach einer vorübergehenden Ausschüttung von polymorphkernigen Leukocyten histiocytäre Granulome. Die Pilze wandern, gefolgt von den Entzündungszellen, durch die Bruchsche Membran in die Retina ein. In den Netzhautgefäßen finden sich hingegen praktisch nie Blastosporen. Für den Bestand des Auges ist dieser Weg, der die Netzhaut offensichtlich weitgehend verschont, von entscheidendem Vorteil, da in der Chorioidea alle Defensivkräfte mobilisiert werden können, die letzten Endes die Zerstörung der eingedrungenen Erreger bewirken.
    Type of Medium: Electronic Resource
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