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Magnetic fine particles of metallic Fe coated with graphitic carbon layers were synthesized by annealing Fe2O3 particles with carbon powders at 1673 K in nitrogen atmosphere. For comparison, SiC was added to Fe2O3. X-ray diffraction measurement showed that the lattice constants of Fe changed depending on the Si contents. Mössbauer spectroscopy confirmed that Fe-Si alloys were formed by the Si addition and that the iron carbide disappeared. Electron microscope images revealed that the thickness of carbon coating layers increased from 24 nm to 36 nm as a result of the Si addition. Soaking tests showed that the corrosion resistance of the carbon-coated Fe particles was improved by the addition of Si. The results suggest that Si caused C to leave the Fe cores and move to the surface to form a carbon coating.  相似文献   
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A survey of plasticizers in cap-sealing resins for bottled foods has been undertaken. During 1997-1999 di-(2- ethylhexyl)phthalate (DEHP) was found in seven out of 21 samples on the Japanese domestic market and in 10 out of 61 imported samples as well as a further two samples which contained di-(2-ethylhexyl)adipate (DEHA). In the period 1993-1999, of the other plasticizers diacetyl lauroyl glycerol (DALG) was only detected in domestic samples whereas diisodecyl phthalate (DIDP) and diisononyl phthalate (DINP) were only in imported samples. It was observed overall that DEHP and DEHA were restricted to use in cap-sealing resins for bottled foods. Whilst phthalates, DEHA or DALG were detected in samples in 1993 and 1995, the investigation in 1997-1999 showed fewer samples in which these plasticizers were found.  相似文献   
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Feeding atomized aqueous solutions containing TiCl4 into an argon high-temperature inductively coupled plasma (ICP) resulted in the formation of mixtures of white and blue particles. The mixtures consisted of anatase and an extra phase of rutile. Adding oxygen to the ICP led to the production of a single phase of white anatase. The blue particles could be characterized as oxygen-deficient anatase. Electrophoretic mobility measurements indicated that Na+ participated in determining the surface potential of the mixtures. The oxygen defects may provide the adsorption sites to Na+.  相似文献   
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Preirradiation grafting of α,β,β-trifluorostyrene onto poly(ethylene–tetrafluoroethylene) film was studied. The trapped radicals formed upon irradiation were able to induce graft polymerization under appropriate conditions. The influences of the grafting conditions were analyzed kinetically. The grafting rate dependency on the preirradiation dose was found to be of order 0.3, and the monomer concentrations, 1.0. The overall activation energies for this grafting were calculated to be 6.2 × 104 and 9.3 × 103 J/mol below and above 50°C. The grafting rate was found to be independent of the film thickness, which ranged from 25 to 100 μm.  相似文献   
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Kupffer cells reside within the liver sinusoid and serve as gatekeepers. They produce pro- and anti-inflammatory cytokines and other biologically important molecules upon the engagement of pattern recognition receptors such as Toll-like receptors. Kupffer cell-ablated mice established by in vivo treatment with clodronate liposomes have revealed many important features of Kupffer cells. In this paper, we review the importance of Kupffer cells in murine acute liver injuries and focus on the following two models: lipopolysaccharide (LPS)-induced liver injury, which is induced by priming with Propionibacterium acnes and subsequent challenge with LPS, and hypercoagulability-mediated acute liver failure such as that in concanavalin A (Con A)-induced hepatitis. Kupffer cells are required for LPS sensitization induced by P. acnes and are a major cellular source of interleukin-18, which induces acute liver injury following LPS challenge. Kupffer cells contribute to Con A-induced acute liver failure by initiating pathogenic, intrasinusoidal thrombosis in collaboration with sinusoidal endothelial cells. The mechanisms underlying these models may shed light on human liver injuries induced by various etiologies such as viral infection and/or abnormal metabolism.  相似文献   
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Colicin D is a plasmid‐encoded antibacterial protein that specifically cleaves the anticodon loops of four Escherichia coli tRNAArg species. Here, we report that the catalytic domain of colicin D, which is expressed in Saccharomyces cerevisiae, impairs cell growth by cleaving specific tRNAs. DNA microarray analysis revealed that mating‐related genes were upregulated, while genes involved in a range of metabolic processes were downregulated, thereby impairing cell growth. The pheromone‐signalling pathway was activated only in α cells by tRNA cleavage, which was not observed in ‘a’ cells or diploid cells. On the basis of these results and on the recent identification of two killer toxins that cleave specific tRNAs, the relationship between tRNA depletion and the resultant cellular response is discussed. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
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