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971.
AA Schreiber K Frei W Lichtensteiger M Schlumpf 《Canadian Metallurgical Quarterly》1993,38(3-4):265-272
Prenatal exposure to diazepam and other benzodiazepines (BDZ) has been found to result in a marked reduction of T-lymphocyte proliferation during postnatal development of rats. In search for pathogenic changes underlying this effect, we investigated the mitogen lipopolysaccharide (LPS) and concanavalin A (ConA) stimulated release of tumour necrosis factor (TNF)-alpha by mixed splenocytes of male offspring from Long Evans rats treated with 1.25 mg/kg per day diazepam from gestational day 14 to 20. In response to LPS, TNF-alpha release was found to be significantly lower in mixed splenocytes of two- and four-week-old treated than in control offspring. However, at eight weeks of age, prenatally diazepam-treated animals showed a significantly higher LPS-induced TNF-alpha release than control rats. Since monocytes/macrophages represent a major source of TNF-alpha, additional experiments were performed on purified spleen macrophages and lymphocytes stimulated with LPS. TNF-alpha release was only detectable in supernatants of adherent spleen macrophages and not in supernatants of lymphocytes. Thus, our data indicate that a disturbance in TNF-alpha release from macrophages is involved in the deficient immune response of prenatally diazepam-exposed rats. 相似文献
972.
Testing Multimedia Transmission Systems 总被引:1,自引:0,他引:1
Digital television and the convergence of television and telecommunications challenges the television engineer to develop new test methods and new ways of using older methods. Supporting multimedia capabilities makes compressed data transmission an important issue. This article outlines a layered model for systems and testing analogous to the OSI model for communications systems and discusses specific test methods for analysis and generation 相似文献
973.
974.
S Murakami I Yamagishi Y Asami M Sato K Tomisawa 《Canadian Metallurgical Quarterly》1996,42(6):865-872
The effects of a novel acyl-CoA: cholesterol acyltransferase (ACAT) inhibitor, HL-004, on cholesterol metabolism were examined in mice peritoneal macrophages. Cholesteryl ester-rich foam cells were induced by incubating macrophages with acetylated LDL. HL-004 prevented the accumulation of cholesteryl ester in the presence of the cholesterol acceptor, HDL. In the absence of HDL, HL-004 generated large amounts of free cholesterol in the cell. Moreover, HL-004 stimulated the efflux of cholesterol from preestablished foam cells in the presence of HDL. These results suggest that the inhibition of foam cell formation and the stimulation of foam cell regression by HL-004 are attributed to intracellular ACAT inhibition, and that HL-004 would be expected to exhibit an antiatherosclerotic effect through direct action on arterial wall. 相似文献
975.
A necessary and sufficient condition for the union of an arbitrary family of fuzzy subgroups of a group to be a fuzzy group has been proposed. The criterion which gives a cut of the unit interval is called the Schnittaxiom. It has been applied successfully to investigate fuzzy subgroupness of arbitrary unions of homomorphic images and preimages. 相似文献
976.
In sheet stamping, friction appears between the tool and the deformed preform. It is of interest to evaluate the difference in the friction coefficient in stamping by tools subjected to different kinds of heat treatment and chemical heat treatment. 相似文献
977.
Is the development of adenoma and carcinoma in proximal colon related to apolipoprotein E phenotype?
K Kervinen H S?dervik J M?kel? J Lehtola M Niemi MI Kairaluoma YA Kes?niemi 《Canadian Metallurgical Quarterly》1996,110(6):1785-1790
BACKGROUND & AIMS: Alterations in plasma lipoprotein levels and bile acid metabolism observed in patients with colorectal adenoma and carcinoma may reflect a genetic background predisposing to altered lipid metabolism and tumors. This study was designed to determine whether the polymorphism of apolipoprotein E, one of the key regulatory proteins in cholesterol metabolism, is associated with proximal or distal colonic neoplasia. METHODS: Apolipoprotein E phenotype was determined in 135 patients with colorectal adenoma, 122 patients with colorectal carcinoma, and 199 randomly selected control subjects. RESULTS: The frequency of the epsilon 4 allele of apolipoprotein E was low (0.075 and 0.073) in patients with proximal adenoma and those with carcinoma, respectively, compared with the control subjects (0.181) (P < 0.05). In patients with distal tumors, there was no alteration in epsilon 4 frequency. In all subjects with the epsilon 4 allele compared with subjects without epsilon 4, the odds ratio for proximal adenoma was 0.36 (95% confidence interval, 0.14-0.89), and the odds ratio for proximal carcinoma was 0.35 (95% confidence interval, 0.14-0.86). CONCLUSIONS: The data suggest that the epsilon 4 allele of apolipoprotein E provides protection from the development of adenoma and carcinoma of the proximal colon. These results support the theory that there are common susceptibility genes modulating the susceptibility to external carcinogenic factors. 相似文献
978.
Experimental evidence of an increase in the resistance of a cathode-side metal line without any void generation is presented for a multilayered metal structure terminated by via-holes during electromigration tests. This resistance increase is reversed to the initial value by high temperature storage after electromigration testing. The increase in the resistance of multilayered metal structures is attributed to the vacancy accumulation in the cathode side due to the blocking barrier effect of the refractory metal layer in the via-hole 相似文献
979.
Samples that are thick with respect to the measuring apparatus can pose problems in the measurement of directional-hemispherical transmittance. Due to the lateral displacement of light that these samples induce, traditional small-beam techniques are often no longer applicable. Broad-area irradiation offers a solution to these problems, but, in practice, imperfections in the extent and the uniformity of the irradiation can create errors. This paper reports measurement of the “detector-integrated inscattering function”, which describes the lateral displacement of light, for a number of thick samples over a range of incidence angles. This function is used to determine the minimum area that must be irradiated for an accurate broad-area irradiation transmittance measurement. The errors caused by transverse non-uniformities in the irradiance distributions produced by a state-of-the-art broad-area irradiation spectrophotometer are also reported. Errors caused by transverse irradiation non-uniformities are estimated, and transmittance measurements made with small-area and broad-area irradiation are compared. It is shown that in most cases small-area irradiation transmittance measurements underestimate the transmittance of thick samples due to outscattering, and that broad-area irradiation measurements using state-of-the-art irradiation optics can contain large errors of up to 20%, due to irradiance non-uniformities, particularly at large angles of incidence. 相似文献
980.
Summary Recent progress in the modelling of exchanged Cu sites and their interactions with small molecules, based on DFT cluster calculations, is briefly reviewed. 相似文献