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  • Chemistry  (3)
  • Beijing Man site  (1)
  • Complement  (1)
  • EXAFS characterization  (1)
  • 1
    ISSN: 1572-9028
    Keywords: CO hydrogenation ; EXAFS characterization ; FTIR characterization ; Ru, RuCo and Co carbonyl clusters in NaY and NaX zeolites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Some Ru and Co carbonyl clusters in zeolite pores such as Ru3(CO)12/NaY, [HRu6(CO)18]−/NaY, [Ru6(CO)18]2−/NaX, Co4(CO)12/NaY and Co6(CO)16/NaY were prepared by the ship-in-bottle technique, and characterized by FTIR and EXAFS. The RuCo bimetallic carbonyl cluster was prepared by reductive carbonylation of the oxidized RuCo/NaY, which provides the proposed assignment to [HRUCo3(CO)12]/NaY. The tailored Ru, RuCo and Co catalysts were prepared by H2 reduction from the precursors, e.g. Ru, RuCo bimetallic and Co carbonyl clusters impregnated on SiO2 and entrapped in NaY and NaX zeolites. The RuCo bimetallic carbonyl cluster-derived catalysts showed substantially higher activities and selectivities for oxygenates such as C1–C5 alcohols in CO hydrogenation (CO/H2 = 0.33-1.0, 5 bar, 519–543 K). By contrast, hydrocarbons such as methane were preferentially obtained on the catalysts prepared from Ru6, Ru3 and Co4 carbonyl clusters and provided lower CO conversion and poor selectivities for oxygenates. The RuCo bimetals are proposed to be associated with the selective formation of higher alcohols in CO hydrogenation.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 282 (1990), S. 183-187 
    ISSN: 1432-069X
    Keywords: Henoch-Schönlein purpura ; Complement ; Cytolysis ; Endothelial cell damage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The present study using direct immunofluorescence with monoclonal antibodies to C5b-9 complex-related antigens was undertaken to determine whether complement activation in Henoch-Schönlein purpura (HSP) causes assembly of the membrane attack complex of complement (MAC) in skin and nephritis lesions. The deposition of C5, C6, C7, C8, C9, and C5b-9 neoantigens was noted in the vascular walls of papillary dermis and/or subpapillary dermal plexus of the vessels in 11 out of 15 patients with HSP. Their presence in vessel walls indicates complement activation which leads to terminal complement activation. There were small deposits of S protein at the same sites in three of the 11 skin specimens. Thus, the majority of C5b-9 demonstrated in HSP skin was the cytolytically active C5b-9 complex, MAC. Granular deposits of C5b-9 related antigens without S protein were also found in the capillary walls and mesangium of the glomeruli of two out of four specimens from patients with HSP nephritis; in the other two S protein was colocalized with the deposition of C5b-9. The results of the present study indicate that complement activation leading to generation of MAC may possibly be involved in the pathogenesis of vascular injury in a significantly large number of skin lesions and of HSP nephritis.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    International journal of anthropology 8 (1993), S. 95-98 
    ISSN: 1824-3096
    Keywords: Beijing Man site ; stalagmitic flowstone calcite ; uranium-series dating
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The chronological position of Beijing Man site was restudied by U-series dating of two calcite samples taken from a stalagmitic flowstone layer intercalated in 1–2 layers. Based on the weighted mean of three measurements performed on the purer one, the upper age limit of this site be 421 −54 +110 ka B.P., much greater than former evaluation of 230 ka based on U-series dating of fossil bones. The reliability of the obtained results was discussed.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biospectroscopy 1 (1995), S. 149-156 
    ISSN: 1075-4261
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: A series of copper bilirubinate complexes (CuBR) was synthesized in solution and in solid state to mimic the black color of the black-pigment gallstone and to explore the formation mechanism of the gallstonein vitro. The variation of the copper contents of these samples indicated that CuBR also exhibits nonstoichiometric characteristics from the FTIR study, i.e., both the so-called acid and neutral copper complex moieties exist in CuBR. The NH groups in pyrrole and lactam groups of bilirubin (H2BR) are binding to the copper ions. An EPR study demonstrates the generation of free radicals and the variation of its electronic structure and conjugation system in the skeleton of H2BR molecule during complex formation. A polymer of CuBR may form through the reaction of H2BR with copper ions. © 1995 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1075-4261
    Keywords: brown pigment stone ; PAGE ; mid-IR spectroscopy ; far IR spectroscopy ; FT-Raman ; bezoar ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Spectroscopic studies of various types of gallstones carried out in China are reviewed. Three basic classes of gallstones are surveyed: cholesterol stones, brown pigment stones, and black pigment stones. The emphasis of this review is on brown gallstones. The primary spectroscopic methods used in the studies surveyed are Fourier transform infrared absorption and Fourier transform Raman scattering. Chemical components studied in gallstones include cholesterol, bile pigments, glycoproteins, proteins, bilirubin metal complexes, and salts of calcium and other metals. Further studies are needed characterize the relationship of these components to more complex features of gallstones. © 1997 John Wiley & Sons, Inc. Biospectroscopy 3: 371-380, 1997
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1075-4261
    Keywords: black pigment gallstone ; FTIR ; EPR ; nonlinear phenomena ; vibrational mode ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Further spectroscopic studies of gallstones are reviewed with an emphasis on the formation of black pigment gallstones. This type of gallstone appears mainly in Western countries, with only 3% of the cholelithiasis patients in China having black gallstones. Fourier transform infrared absorption and electron paramagnetic resonance are used as spectroscopic probes of gallstones and their metal bilirubinate components. Nonlinear phenomena in gallstone formation were investigated through the appearance of ring structure in gallstones and fractal patterns in the formation in the precipitates of bile salt systems. Although a complete understanding of gallstone formation has not yet been achieved, interesting progress toward this goal has been made recently. © 1997 John Wiley & Sons, Inc. Biospectroscopy 3: 381-391, 1997
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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