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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Water, air & soil pollution 5 (1976), S. 469-490 
    ISSN: 1573-2932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The concentrations of organic matter, major elements and trace elements were determined at 14 core locations in Lakes Ontario, Erie and Huron. The chemical composition of the cores was related to the sediment particle size, Eh, pH, chronology and location of sampling site. Concentrations of Si, Al, Fe, Mg, Ti, K and Na, which represent the major mineral species in the sediments, are generally uniform in each core. Surface enrichments of Hg, Pb, Zn, Cd, Cu, Be, V, Org-C, N and P are observed at most locations, with their concentrations, usually much greater above the Ambrosia horizon (≈ 120 yr BP), irrespective of the depth of the horizon. The enrichment of these elements is attributed to anthropogenic inputs in recent years. Concentration profiles for Mn and S are related to the migration of these elements in the pore waters. Anthropogenic loadings of the trace metals and nutrients parallel the population and degree of industrialization of each lake drainage basin. Natural loadings parallel the sedimentation rates. Although it is not possible to evaluate the contributions of the trace metals from various sources, evidence is presented that atmospheric inputs are important.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-2932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The concentrations of organic matter, major elements and trace elements were determined at 15 core locations in Lake Superior and Huron. The chemical compositions of the cores are related to sediment particle size, Eh, pH, chronology and location. Concentrations of Si, Al, Ca, Mg, K, Na, and Ti, which represent the major mineral species in the sediments, are generally uniform in each core. Surface enrichments of Hg, Pb, Zn, Cu, Ni, Co, Cd, Cr, Be, V, As, Org-C, and N at many of the locations are attributed to anthropogenic inputs of these elements in recent years. Concentration profiles of Fe, Mn, P, and S are influenced by migration of these elements in the pore waters. High anthropogenic Cu loadings in Lake Superior were related to Cu mining activities in the lake basin, while high anthropogenic inputs of Ni to the Lake Huron sediments were related to Ni contamination from the Sudbury area. Sediment loading calculations show that the anthropogenic inputs of trace and nutrient elements are related to the sedimentation rate, that the inputs are dispersed over wide areas of the lakes and that inputs to Lake Superior have increased significantly since 1955. Evidence is presented that atmospheric inputs are an important source of contaminants.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 3 (1975), S. 284-296 
    ISSN: 0091-7419
    Keywords: Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The tightly bound nucleotides of the beef-heart mitochondrial ATPase are released during cold inactivation followed by ammonium sulfate precipitation. During incubation at 0°C the sedimentation coefficient (s20 W) of the ATPase first declines from 12.1 S to 9 S. Prolonged incubation or precipitation with ammonium sulfate leads to dissociation of the 9 S component into subunits with s20 W of 3.5 S. The 9 S component still bears bound nucleotides which exchange more extensively and rapidly with added nucleotides than those bound to the active 12.1 S component. The bound nucleotides are lost when the 9 S form dissociates into the smaller subunits. Thus, firm binding of nucleotides is a property of the quarternary structure of the enzyme.The exchangeability of the nucleotides bound to the ATPase of chloroplast membranes is greatly increased in membranes illuminated in the presence of pyocyanine. Pi can exchange into both the β and γ positions of the bound nucleotides when the membranes are energized in the presence of Mg2+. The exchange of the nucleotides and the incorporation of Pi are insensitive to the inhibitor Dio-9 but are inhibited by the uncoupler S13.Abbreviation: S13, 5-chloro-3-t-butyl-2′-chloro-4′nitrosalicylanilide. This inhibition by S13 parallels that of the inhibition of photosynthetic phosphorylation. These findings are discussed with regard to our hypothesis that electron transfer causes release of preformed tightly bound ATP from the ATPase by inducing a conformational change.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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