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  • chemosystematics.  (4)
  • Physics  (3)
  • Key words Brackish Lake Obuchi  (2)
  • (-)-2-(1,2,2-trimethyl)-cyclopentyl-6-methyl-1,4-quinone  (1)
  • 1
    ISSN: 0031-9422
    Keywords: F. californica ; F. nepalensis ; Frullania tamarisci ; Hepaticae ; Jungermanniales ; chemosystematics. ; mossy odour ; sesquiterpene alcohol ; sesquiterpene lactones ; tamariscol
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Phytochemistry 30 (1991), S. 219-234 
    ISSN: 0031-9422
    Keywords: 5-lipoxygenase and calmodulin inhibitory activity ; Hepaticae ; Jungermanniales ; Radula kojana ; Radulaceae ; benzofuran ; bis(bibenzyls) ; chemosystematics. ; chromenes ; prenyl bibenzyls ; synthesis
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Phytochemistry 29 (1990), S. 2197-2199 
    ISSN: 0031-9422
    Keywords: B. harpago ; B. praerupta ; Bazzania spiralis ; Hepaticae ; Jungermanniales ; chemosystematics. ; ent-8β-hydroxy-eudesma-3, 11-diene ; ent-eudesmane-type sesquiterpenoids ; ent-α-selinene
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Phytochemistry 30 (1991), S. 4019-4024 
    ISSN: 0031-9422
    Keywords: Chandonathus hirtellus ; Frullania serratta ; Hepaticae ; Heteroscyphus aselliformis ; Lepidozia borneensis ; Mastigophora diclados ; Scapania javanica ; Schistochila aligera ; Trichocolea pluma ; Wiesnerelia denudata ; bibenzyls ; chemosystematics. ; cyclic bis(bibenzyls ; isocuparene dimers ; prenyl benzoates ; sesquiterpenoids
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Phytochemistry 30 (1991), S. 325-328 
    ISSN: 0031-9422
    Keywords: (-)-2-(1,2,2-trimethyl)-cyclopentyl-6-methyl-1,4-quinone ; Hepaticae ; Jungermanniales ; Radula javanica ; bibenzyls ; cuparene-type sesquiterpene quinone. ; cyclopropanochromans ; radulanins I, J and K
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1439-863X
    Keywords: Key words Brackish Lake Obuchi ; Uranium ; Sediment ; Physicochemical form ; Sequential extraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The physicochemical form of uranium (238U) in the sediment of brackish Lake Obuchi was investigated using the standard procedures of sequential extraction. Approximately 60% to 70% of 238U was composed of the form bound to carbonates and iron (Fe)-manganese (Mn) oxides in silty sediments, whereas more than 50% of 238U existed in the minerals of sandy sediments. The proportions of 238U bound to carbonates in the sediments of brackish Lake Obuchi were larger than those in fresh-water lake sediments. Most of the uranium in the brackish lake sediment was considered to be mainly influenced by UO2(CO3)3 4− in seawater, judging from the fact that the 234U/ 238U activity ratios (1.13 to 1.16) of silty sediments were very close to that of seawater (1.14). The high correlation found between the 238U concentration in the sediment and the amount of organic matter demonstrated that organic matter acts as a scavenger for 238U accumulation on the lake bottom.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1439-863X
    Keywords: Key words Brackish Lake Obuchi ; Salinity ; Water quality ; Density gradient
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fluctuations in the salinity and physicochemical characteristics of water quality were surveyed in brackish Lake Obuchi on the Shimokita Peninsula in Aomori, Japan. The mean salinity in the surface layer in all regions of Lake Obuchi was about 10 psu, whereas in the basin region at depths of greater than 3 m it was 20 psu. Furthermore, all the year round the halocline was formed at depths of 1–4 m. The maximum density gradient along a vertical axis in the center of the lake was observed at depths of 1–2 m in summer and 2–4 m in spring and fall. The depth of the maximum density gradient fluctuated with the seasons. In summer the water in the bottom layer was anoxic, and Fe, Mn, PO4 3−-P, and NH4 +-N supplied from the bottom sediment accumulated at high concentrations below the halocline. Thus, it was observed that the transfer of substances between the layers above and below the barrier formed by the halocline is suppressed. Although Lake Obuchi is small and shallow, the inflowing seawater easily resides, and a stable halocline readily forms because of the shape of its basin, which suddenly deepens on the Pacific Ocean side.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 15 (1977), S. 2059-2065 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Oxidation of hydroquinone catalyzed by copper(II) complexes of poly-1-vinylimidazole, vinylamine-vinylacetamide copolymer, and polyethyleneimine was studied in aqueous solution at 25°C. The rate of oxidation was determined spectrophotometrically over several pH values. The rate of copper(II) reduction was evaluated from copper(I)-cuproin complex formation, and the reoxidation of copper(I) to copper(II) was observed by visible spectroscopy. Among the copper(II) complexes, poly-1-vinylimidazole complex exhibited excellent catalytic activity, which amounted to over 20 times that of aqueous copper(II) ion solution, while the reduction of copper(II) in the former system was slower than that in the latter system. The reoxidation of copper(I) to copper(II) was found to be completed immediately in the presence of polymer ligands such as poly-1-vinylimidazole, while copper(I) ion was only slowly reoxidized. The discussion of the reaction mechanism emphasizes the importance of the reoxidation process.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 17 (1979), S. 2729-2737 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The autoxidation of Cu(I) complexes with imidazole and polyvinylimidazole derivatives was studied by observing the formation of the corresponding Cu(II) complexes with a stopped-flow technique. The reaction was second order and proportional to the concentrations of Cu(I) and oxygen. In the Cu(I)-imidazole complex pH variation was without effect in the range of 7.5-8.6. The oxidation rate of Cu(I).polyvinylimidazole complexes, on the other hand, decreased with a rise in pH. The activation parameters of the Cu(I)·polyvinylimidazole complexes, compared with those of the Cu(I).imidazole complex, were characterized by large enthalpic requirements coupled with favorable entropies of activation. This was explained by the fact that a conformational change in the polymeric ligands took place during oxidation.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 101-107 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Cu(II) complexes of copolymers having pendant sulfide and imidazolyl groups were prepared by a free radical copolymerization of ethylvinylsulfide with vinylimidazole, and their properties and function were studied spectrophotometrically in comparison with those of poly[4(5)-vinylimidazole]. The complexes were found to be effective as catalysts for the oxidation of hydroquinone. Visible and ESR spectra of the Cu(II)-copolymer complexes were similar to those of the Cu(II)-homopolymer complexes, while the catalytic activity for the oxidation was different between these complex systems. A rapid reaction followed by a slow reaction, particularly at high ethylvinylsulfide content in the copolymers, was observed in the Cu(II)-copolymer complex systems, but a continuous reaction proportional to the reaction time was observed in the Cu(II)-homopolymer complex systems. The reoxidation rate of Cu(I) to Cu(II) complex, which was little affected by the concentration of imidazolyl group, decreased with a rise of the ethylvinylsulfide content in the copolymer. It was suggested that the sulfur atom of the sulfide group was weakly coordinated to Cu(II) but strongly to Cu(I), and an electron transfer reaction from substrate to the Cu(II) complex was increased, while reoxidation reaction of the Cu(I) complex was decreased in the copolymer complex systems.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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