Process of commutation of a vacuum electric-discharge gap by laser plasma

The temporal parameters of a process of vacuum gap commutation under exposure to a nanosecond pulse of laser radiation incident on the cathode has been studied depending on the radiation energy. Based on the experiment data, it is suggested that a glow discharge is initially ignited in electrode erosion products under exposure to the laser pulse, which due to development of the ionization-overheating instability undergoes the contraction of current channel and transits to an arc discharge. With the radiation energy exceeding a threshold value, the radiation (incident on the cathode) accelerates directly the instability development and the glow discharge transition to the arc discharge due to the radiation absorption in the discharge plasma.     

Interannual Variations in Species Richness and Quantitative Parameters of Macrozoobenthos in Floodplain Lakes of the Khoper Nature Reserve

Interannual variations in species richness and quantitative parameters of macrozoobenthos in floodplain lakes of the Khoper Nature Reserve have been studied to reveal their dependence on flood regime and overgrowth by macrophytes. It has been shown that a particular species richness of macrozoobenthos is preserved for several years. Interannual variations in characteristics of lakes, particularly in the flood period, determine the changes in quantitative parameters of macrozoobenthos. The overgrowth rate of lakes by macrophytes does not exert an effect on species richness and quantitative parameters of macrozoobenthos, but determines its saprobiological structure. The flood period necessary for the formation of the most abundant communities of macrozoobenthos in the studied lakes is 30 days. Nevertheless, this is not the main factor determining its quantity in lakes constantly connected with the river by a channel. It is confirmed that drying or a sharp drop in water content of the river play the role of a trapping point and triggers ecosystem transformations in small water bodies.     

Activation of glucocorticoid cytoreceptors in rat heart]

Accumulation of 3H-dexamethasone by the nuclei in a cell-free system was studied. The increase in temperature from 0 degrees to 20 degrees C and treatment of cytosol by KCl (0.4 M) or theophylline (10mM) significantly increased the absorption the bound hormone by the nuclear fraction. Activation of the steroid-protein complex induced by temperature and addition of theophylline did not change its size. The increase in the ionic strength decreased the Stokes radius from 53 A down to 39.5 A and the sedimentation coefficient value from 7S down to 4S. It is concluded that the heart tissue cytoplasm contains a glucocorticoid receptor.     

Experimental Justification of Approaches to Developing Pathogenetic Means towards the Prevention and Treatment of Early Postradiation Gastrointestinal Disorders

Biology Bulletin - Experiments on dogs have shown that antagonists of receptor types D2 (domperidone, metoclopramide, dimethpramide), 5-HT3 (ondansetron, palonosetron), and NK1 (aprepitant) impair...