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991.
GC Papavizas 《Canadian Metallurgical Quarterly》1976,22(7):1034-1039
Studies on volatile soil fungistasis showed that sclerotia of Macrophomina phaseolina are not sensitive to volatiles liberated by natural soils with varying pH values. Soil amended with alfalfa hay (1%, w/w) liberated volatiles fungistatic to sclerotia only when the assay was performed 2 weeks or less after amendment. Chitin-amended soils liberated fungistatic volatiles from 1 to 3 weeks after amendment. Indirect evidence indicated that ammonia may be the active volatile in amended soil. It was concluded that fungistatic volatiles may not play an important role in the survival of sclerotia in nature. 相似文献
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994.
The effects of several known inhibitors and activators of peroxidase-catalyzed reactions have been studied on the NADPH oxidase activity of granules isolated from polymorphonuclear leukocytes at rest or during phagocytosis. Redogenic substances, such as ascorbate or hydroquinone, and superoxide dismutase, which are known to inhibit peroxidase-catalyzed reactions, also inhibited the NADPH oxidase activity of granules. Oxidogenic substances, such as guaiacol or resorcinol, and manganese, which are known to stimulate peroxidase-catalyzed reactions, also activated the NADPH oxidase activity of granules. Cyanide, an inhibitor of peroxidase-catalyzed reactions, inhibited the NADPH oxidase activity of granules isolated from resting leukocytes but only slightly affected that of granules isolated from phagocytosing cells, as previously reported. A list of the properties of the NADPH oxidase activity of granules and of peroxidase oxidase activity is given. The arguments in favor of and those against a possible identity of the two activities are discussed. 相似文献
995.
Hypothyroidism is generally associated with hypogonadotropism. Occasionally, however, increased gonadotropin concentrations are encountered. The mechanisms, presumably hypothalamic, which determine the gonadotropin shift are unclear. A case report of hyperprolactinemic hypothyroidism with associated hypergonadotropism is presented. The previous literature is reviewed. It appears that hypothyroidism is generally associated with a decrease in the gonadogropin secretion. However, hypothyroidism with exxagerated hTSH secretin and hyperprolactinemia can be associated with increased gonadotropin secretion. 相似文献
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999.
Recovery based error estimation and adaptivity applied to a modified element-free Galerkin method 总被引:1,自引:0,他引:1
In this work, we propose an error estimator of the recovery type, which considers the equilibrium and boundary traction conditions, and an h-refinement procedure that is applied to the modified element-free Galerkin (MEFG) method. The approximate solution obtained by the MEFG method satisfies accurately the essential boundary condition. However, the approximate MEFG stress field presents some discontinuities on a neighborhood of the essential boundary condition and may present some spurious oscillations at regions of high stress gradients or discontinuities. Thus, the h-adaptive scheme is responsible for the reduction not only of the global error but also of the local errors associated with the discontinuities and oscillations of the approximate stress field. In order to validate the proposed procedures, we present some numerical solution for some simple problems and consider the analysis of a complex component.We want to acknowledge the support of the CNPq – Conselho Nacional de Desenvolvimento Científico e Tecnológico – of Brazil. Grant Numbers: 470426/01-2 and 141806/2000-1. 相似文献
1000.
P. Ciambelli S. Cimino S. De Rossi L. Lisi G. Minelli P. Porta G. Russo 《Applied catalysis. B, Environmental》2001,29(4):232-250
Catalytic methane combustion and CO oxidation were investigated over AFeO3 (A=La, Nd, Sm) and LaFe1−xMgxO3 (x=0.1, 0.2, 0.3, 0.4, 0.5) perovskites prepared by citrate method and calcined at 1073 K. The catalysts were characterized by X-ray diffraction (XRD). Redox properties and the content of Fe4+ were derived from temperature programmed reduction (TPR). Specific surface areas (SA) of perovskites were in 2.3–9.7 m2 g−1 range. XRD analysis showed that LaFeO3, NdFeO3, SmFeO3 and LaFe1−xMgxO3 (x·0.3) are single phase perovskite-type oxides. Traces of La2O3, in addition to the perovskite phase, were detected in the LaFe1−xMgxO3 catalysts with x=0.4 and 0.5. TPR gave evidence of the presence in AFeO3 of a very small fraction of Fe4+ which reduces to Fe3+. The fraction of Fe4+ in the LaFe1−xMgxO3 samples increased with increasing magnesium content up to x=0.2, then it remained nearly constant. Catalytic activity tests showed that all samples gave methane and CO complete conversion with 100% selectivity to CO2 below 973 and 773 K, respectively. For the AFeO3 materials the order of activity towards methane combustion is La>Nd>Sm, whereas the activity, per unit SA, of the LaFe1−xMgxO3 catalysts decreases with the amount of Mg at least for the catalysts showing a single perovskite phase (x=0.3). Concerning the CO oxidation, the order of activity for the AFeO3 materials is Nd>La>Sm, while the activity (per unit SA) of the LaFe1−xMgxO3 catalysts decreases at high magnesium content. 相似文献