Methane accumulation in non-ventilated blind coal roadways

The authors propose a theoretical solution to the problem on the air displacement by methane in blind coal roadways when their ventilation is ceased. Dependences of methane ingress rate into a coal roadway and time for methane concentration to reach maximum admissible level in the roadway on coal gas content, methane filtration factor, coal’s open and closed porosity, roadway advance, conveyor speed, size of broken coal lumps and other geotechnical factors are established.     

Cloning and characterization of a novel upstream untranslated exon of the mouse Fgf-1 gene

Several recent studies have reported that there is an imbalance of increased oxidant status and decreased antioxidant system in women with preeclampsia and that factor might contribute to the pathogenesis of the disease. The following study examined blood levels of some of the antioxidants (glutathione, glutathione-peroxidase and -SH groups) as markers of lipid peroxidation in women with preeclampsia compared with normal gestation. Blood levels of these antioxidants were found significantly decreased in women with preeclampsia, which allowed us to speculate that there were abnormally increased levels of lipid peroxides. We believe that lipid peroxides are toxic compounds that damage endothelial cells, increase peripheral vasoconstriction and increase thromboxane synthesis and decrease prostacyclin synthesis. We consider that lipid peroxides are not the cause but the effect of oxidative stress induced by ischaemic placenta and leukocytes activation, so the contribute but not induce pathogenesis in preeclampsia.     

Residual stresses in a transversely plastically deformed body containing thin tunnel inclusions

Summary Singular integral equations have been used to solve for the approximate residual-stress concentration in the matrix around thin tunnel inclusions; we consider the cases of one isolated inclusion as well as periodic systems of elliptical ones placed coplanar or in parallel planes. Closed solutions are obtained. Laboratory tension tests have been used in estimating the residual stresses in a steel matrix containing a tunnel copper elliptical inclusion.Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 25, No. 2, pp. 19–23, March–April, 1989.     

Spark-proof strain-gauge pressure sensors and a signal-normalization device

Translated from Izmeritel'naya Tekhnika, No. 5, pp. 35–36, May, 1993.