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161.
NK Karamanos P Vanky GN Tzanakakis T Tsegenidis A Hjerpe 《Canadian Metallurgical Quarterly》1997,765(2):169-179
Rats deficient in vitamin A express low levels of P4502C7 mRNA in the liver. Administration of all-trans retinoic acid (at-RA) or growth hormone (GH) to deficient animals only partially restored the expression whereas the combined treatment returned the P4502C7 mRNA levels to that observed in normal rats. That a retinoid is the predominant inducer of P4502C7 at the cellular level is evident from studies performed with primary hepatocytes, but it became clear that GH is a prerequisite for the vitamin A effect in vivo. The at-RA induction of P4502C7 mRNA in primary rat hepatocytes was inhibited by ketoconazole, an inhibitor of P450 activity, and by cycloheximide, blocking ongoing protein synthesis. In contrast, the at-RA induction of RAR-beta2 mRNA was not affected by any of these compounds. This could indicate previously not recognized mechanisms of at-RA action. Interestingly, at-4-oxo-RA, an at-RA metabolite formed by a P450 catalyzed reaction, also induced P4502C7 mRNA. Induction of P4502C7 mRNA by the retinoic acid receptor (RAR) selective agonist TTNPB indicated that this pathway is preferred over the retinoid X receptor (RXR) pathway. In addition, analysis of RA metabolites in liver cell extracts revealed the formation of several as yet unidentified metabolites. The formation of some of these metabolites was inhibited by ketoconazole and they could therefore constitute potential inducers of CYP2C7. We suggest that metabolism of at-RA, possibly by a P450 enzyme, is an important step in the at-RA induction of P4502C7. 相似文献
162.
A. N. Alekhnovich N. V. Artem’eva V. V. Bogomolov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2007,41(2):105-110
The paper is devoted to substantiation and prediction of the allowable gas temperature at the outlet from a furnace subject
to slagging. The non-optimality of values recommended by effective methodical instructions regarding the design of furnace
devices is demonstrated. Utilizing knowledge gained from temperature measurements in boilers, and the situation regarding
the slagging of heating surfaces located at the outlet from the furnace, new, frequently higher values are proposed. A method
for evaluating the allowable gas temperature at the outlet froma furnace subject to slagging is suggested on the basis of
data regarding the chemical composition of the mineral portion of coals.
__________
Translated from élektricheskie Stantsii, No. 2, February, 2007, pp. 23–28. 相似文献
163.
I. S. Edelman R. D. Ivantsov I. G. Vasil’eva A. D. Vasil’ev O. A. Bayukov O. S. Ivanova D. E. Prokof’ev S. A. Stepanov E. E. Kornilova T. V. Zarubina V. V. Malakhov V. A. Zaikovskii 《The Physics of Metals and Metallography》2006,101(1):S2-S5
Dependence of the magnetic moment of square arrays of Josephson junctions on a dc magnetic field and temperature has been studied experimentally. The arrays had junctions of SIS and SNS type. In SIS arrays, magnetic flux avalanches were observed at low temperatures. Statistical size distribution of magnetic avalanches is a power function with a crossover (the exponent changes from ?0.7 for small sizes of avalanches to ?6 for large sizes). The spectrum of avalanches at a linear development of the field is a power function of frequency. Such a behavior of avalanches is interpreted as a manifestation of the self-organized criticality. In SNS arrays, no avalanches are developed because of the high dissipation in junctions, but a considerable asymmetry of magnetic dynamics was found. 相似文献
164.
165.
The effects of midazolam (MID) on the in vitro growth and differentiation of two murine myeloid leukemia WEHI 3B (JCS) and M1 cells were studied. MID inhibits the proliferation of both M1 and JCS cells in a dose-dependent manner. At the concentration of 10 micrograms/ml, MID was found to induce both monocytic and granulocytic differentiation of the JCS but not M1 cells. Induction of morphological differentiation of the JCS cells was also associated with the enhanced expression of the differentiation antigens Mac-1, F4/80, and Gr-1 for the cells. Results from mRNA phenotyping experiments also indicated that the expression of tumor necrosis factor (TNF-alpha) and neutrophil-specific J11d differentiation marker was significantly upregulated in MID-treated JCS cells. In addition, the phagocytic activity of MID-treated JCS cells was increased towards opsonized yeast cells. Results from this investigation suggested that MID may be used as an inducer for further study on the mechanisms of differentiation in these myeloid leukemia cells. 相似文献
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