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  • Particle-induced X-ray emission  (1)
  • emissions  (1)
Materialart
Erscheinungszeitraum
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Neurochemical research 14 (1989), S. 1099-1112 
    ISSN: 1573-6903
    Schlagwort(e): Particle-induced X-ray emission ; elements ; age ; human brain
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Eight elements (i.e. K, Ca, Mn, Fe, Cu, Zn, Se, and Rb) were measured in 50 different regions of 12 normal human brains by particle-induced X-ray emission (PIXE) analysis. The dry weight concentrations of K, Fe, Cu, Zn, Se, and Rb were consistently higher for gray than for white matter areas. The K, Zn and Se concentrations for the regions of mixed composition and, to some extent, also the Rb concentrations, were intermediate between the gray and white matter values, and they tended to decrease with decreasing neuron density. The mean dry weight concentrations of K, Ca, Zn, Se, and Rb in the various brain regions were highly correlated with the mean wet-to-dry weight ratios of these regions. For Mn, Fe, and Cu, however, such a correlation was not observed, and these elements exhibited elevated levels in several structures of the basal ganglia. For K, Fe, and Se the concentrations seemed to change with age. A hierarchical cluster analysis indicated that the structures clustered into two large groups, one comprising gray and mixed matter regions, the other white and mixed matter areas. Brain structures involved in the same physiological function or morphologically similar regions often conglomerated in a single subcluster.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Water, air & soil pollution 85 (1995), S. 1933-1940 
    ISSN: 1573-2932
    Schlagwort(e): acid precipitation ; base cations ; emissions ; airborne concentrations ; deposition in Europe
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract Mineral dust in the atmosphere is generally alkaline, and is a source of base cations in precipitation. Annual emissions of particles from large combustion plants and industrial processes in Europe is of the order of 24 million tonnes, and the calcium content may be as high as 1.4 million tonnes. Emissions from diffuse sources such as agricultural activities, construction and quarrying are much less well known. Emissions of dust from the Sahara have been estimated to more than 200 tonnes, with a calcium content of 3–5%. In northern Europe, airborne concentrations of calcium and the concentration of calcium in precipitation are generally consistent with the anthropogenic emissions and their regional distribution. Transport of dust from Sahara is a major source of base cations in precipitation around the Mediterranean Sea, but the influence diminishes further north. The concentration of calcium in precipitation decreases from south to north and from east to west in Europe. Dry deposition of alkaline particles is not well documented, but may be at least as high as the input by precipitation in regions where there are large emissions. There are still large uncertainty gaps with respect to emissions, transport and deposition of calcium-containing particles.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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