A magnetic resonance imaging (MRI) method was used for a noninvasive study of current density (CD) and current pathways (CP's) inside the skull during transcranial electrostimulation in rabbits. The transcranial impulse current directions studied were those previously used in transcranial electric treatment either sagittally or bilaterally. MRI data were collected from slices perpendicular to the direction of current application. In these slices, only the perpendicular component of the CD was measured. Computer methods for accurate topographic mapping of the main areas with high CD and for reconstruction of CP's are described. It was revealed that current applied on the head sagittally passed mostly through the cerebrospinal fluid in the basal brain cisternas connected in series, and through the anterior horns of the lateral ventricles, foramina of Monro, ventrocaudal part of the third ventricle, aqueductus, and fourth ventricle. Possible connections between these CP's are suggested. Bilaterally applied current passed through the brain and skull core more diffusely without concentrations in cisternas and ventricles. The results of the present study suggest an explanation for the observation that sagittally applied current more effectively stimulates brain structures with antinociceptive function and elicits more pronounced analgesic effect.

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It is well known that deficit of endorphins plays an important role in disturbances of human psycho-physiological status. Previously, we revealed that brain endorphinergic structures have quasiresonance characteristics. On the basis of these data, a method of activation of the brain endorphinergic structures by means of noninvasive and rather selective transcranial electrostimulation (TES) as a kind of functional electrical stimulation (FES) was elaborated. New models of TES devices (TRANSAIR) were developed for indoor and outdoor usage. To increase the efficacy of TES, the frequency modulation according to normal distribution in the limits of the quasiresonance characteristics was put into operation. The blind and placebo-controlled (passive and active placebo) study was produced to estimate the TES effects on stress events and accompanied psycho-physiological and autonomic disturbances of different intensities on volunteers and patients in the following groups: everyday stress and fatigue; stress in regular military service and in field conditions; stress in the relatives of those lost in mass disaster; posttraumatic stress (thermal burns); and affective disorders in a postabstinence period. Some subjective verbal and nonverbal tests and objective tests (including heart rate variability) were used for estimation of the initial level of psycho-physiological status, which changes after TES sessions. It was demonstrated that fatigue, stress, and other accompanied psycho-physiological disturbances were significantly improved or abolished after 2-5 TES sessions. The TES effects were more pronounced in cases of heavier disturbances. In conclusion, activation of the brain endorphinergic structures by TES is an effective homeostatic method of FES that sufficiently improves quality of life.

In the present work we experimentally examined the effect of enhanced freestream turbulence on the film-cooling efficiency in an axisymmetric supersonic nozzle. A considerable reduction in the film-cooling efficiency was observed with increasing level of flow turbulence, both in the subsonic and supersonic parts of the Laval nozzle. For instance, an increase in the freestream turbulence number from 0.2% to 15% resulted in more than twofold deterioration of film-cooling efficiency. A similar decrease of film-cooling efficiency was also observed under off-design flow conditions. At the same time, the increase in the freestream turbulence number had almost no effect on the recovery factor and on the distribution of static pressure over the length of the nozzle. The Kutateladze-Leont'ev asymptotic theory of gas cooling films was used to generalize the experimental data for nozzle flows with allowance for flow nonisothermality, compressibility, longitudinal pressure gradient, and high freestream turbulence number.