Quantitative analysis of neurological effects after cranio-caudal gamma-irradiation of rats

A study was made of the frequency and duration of neurological disorders after cranio-caudal irradiation of rats with doses of 7.5-500 Gy delivered to the head. As the mean effective dose increased the neurological disorders occurred in the following order: tremor, rotatory movements hyperkinesia, opisthotonos, and convulsions. The neurophysiological disorders observed were subjected to a pathophysiological analysis.     

Dynamics of the plasma injected into the gap of a plasma opening switch across a strong magnetic field

A method is proposed to increase the linear charge density transferred through a plasma opening switch (POS) and, accordingly, reduce the POS diameter by enhancing the external magnetic field in the POS gap. Results are presented from experimental studies of the dynamics of the plasma injected into the POS gap across a strong magnetic field. The possibility of closing the POS gap by the plasma injected across an external magnetic field of up to 60 kG is demonstrated.     

Influence of mutual arrangement of the electric dipole and the spatial nonuniformity of brain electrical conductivity on the solution of the direct task of electroencephalography using the method of finite elements

The results of comparing the solutions of the direct task of electroencephalography on a spherical model and a spherical model with one nonuniformity are discussed. The nonuniformity was simulated by two parabolas situated on the same axis of symmetry and crossing the boundary of the gray and the white matter. The region between the larger and the smaller parabolas had the physical characteristics of the gray matter, and the region inside the smaller parabola had the characteristics of the cerebrospinal fluid. The task was to find a combination of parameters (distance between the dipole and the nonuniformity, angle of rotation of the dipole relative to the nonuniformity, sizes of the dipole and the nonuniformity, etc.) that provides the maximum effect of the difference of potentials on the outer surface of the scalp in the spherical model with one nonuniformity and the spherical model. The influence of the points of grounding on the value of the effect was analyzed (ground only at the right ear and ground at both ears). The data obtained show that a maximum difference of potentials is reached at the positions of dipoles close to tangential relative to the scalp surface.     

Outlook for the use of microsecond plasma opening switches to generate high-power nanosecond current pulses

An analysis is made of the current break process in microsecond plasma opening switches and their possible application in high-current generators. Necessary conditions are determined for generating megavolt pulses in the erosion mode of a plasma opening switch with the gap insulated by an external magnetic field. Under these conditions, efficient sharpening of high-power submegampere current pulses can be achieved. The possibility of using plasma opening switches operating at voltages of 5–6 MV to generate X-ray and gamma emission is discussed. The main operating and design parameters of a six-module plasma opening switch with a current pulse amplitude of 3.7 MA and voltage of 4–6 MV for use in the MOL generator, which is the prototype of one of the 24 modules of the projected Baikal multimegajoule generator, are estimated by using the available scalings.     

Cytochemical determination of the enzyme activity of cerebrospinal fluid lymphocytes in dogs

Cytochemical methods commonly used in hematology were applied to studying the liquor lymphocytes of dogs. According to our observation of decreasing their activity, the enzymes examined are placed in the following order: alpha-glycerophosphate, glutamate, lactate, and succinate dehydrogenase. High and reliable values of asymmetry and excess coefficients show the absence of the normal distribution of enzymatic activity in the investigated population of lymphocytes.     

Effect of gamma-irradiation on the enzyme activity of cerebrospinal fluid lymphocytes in dogs

Cytochemical activity of succinate dehydrogenase (SDG), L-glycerophosphate dehydrogenase (L-GPDG), lactate dehydrogenase (LDG), and glutamate dehydrogenase (GDG) increased immediately after total-body irradiation with a dose of 129 mC/kg. After 2 h, LDG activity only returned to the control level. Irradiation of the head with the same dose caused less pronounced changes. Changes caused by lethal irradiation (1290 mC/kg) were different: there was an increase after exposure of the abdomen and a decrease in the activity of SDG and L-GPDG after irradiation of the head.