Potential capabilities of aircraft laser landing systems.

We present calculations of the efficiency of the laser landing system (LLS), based on determining the minimum required fluxes of scattered radiation from fixed extended landmarks (FELs), which are LLS indicators in the case of visual FEL detection under real operation conditions. It is shown that, when the meteorological visibility range Sm=800 m, for reliable detection of laser beams from the glissade slope group at ranges L∼1.0-1.6 km under nighttime conditions, the minimum required powers are Pmin=0.5 W for λ=0.52 and 0.64 µm, given deviations from the glissade path by the angle ϕ=0°-5°. The green and red rays are visible at distances L=1-1.2 km under twilight conditions. Our calculations corroborated the possibility of creating a new-generation laser-based LLS capable of ensuring aircraft landing under the conditions of International Civil Aviation Organization category 1 (decision height of 60 m at the minimum visibility equal 800 m).

[Mechanism of development of epidemic process of group A streptococcal infection in children collectives].

AIM: To study the characteristics of group A streptococcal infection epidemic process in children aged 12 - 14 years arrived to summer camp "Orlenok" (Tuapse) from different regions of Russia. MATERIALS AND METHODS: Epidemiological (retrospective analysis of incidence of acute respiratory infections, tonsillitis, and scarlet fever), microbiological (isolation and identification of group A streptococci [GAS]), and molecular biological (pulse-electrophoresis, analysis of spe and emm genes) methods were used for the study. Objects of the study were GAS strains isolated from patients and carriers. RESULTS: Performed genotyping showed that cases of GAS infection in newly formed children collectives were caused by 2 - 3 epidemically important clones, which were genotypically heterogenous. CONCLUSION: Performed molecular biologic studies demonstrated polyclonal structure of GAS that determines the features of development of epidemic process.

[Influence of climatic and geographic factors on the environmental distribution of heavy metals and children's health].

The authors have studied the environmental distribution of salts of heavy metals (cadmium and nickel) under the influence of climatic and geographic factors and formation of geochemical anomalies. They also examined regularities in the accumulation of heavy metals in children's biosubstrates (hair, urine) and the nature of impact of their levels on the physical development of children in the organized collective bodies (preschool institutions) located in anomalous areas.

[Structure of visual pathways in the nervous system of fresh water pulmonary molluscs].

The central nervous system of freshwater pulmonary molluscs Lymnaea stagnalis and Planorbarins corneus was stained by the method of neurobiotin retrograde transport along optic nerve fibers. In the animals of both species, bodies and fibers of stained neurons are found in all ganglia except for the buccal ones. Afferent fibers of the optic nerve form a dense sensor neuropil located in a small volume of cerebral ganglia. Characteristic groups of neurons sending their processes into optic nerves both of ipsi- and of contralateral half of the body are described. Revealed among them are neurons of visceral and parietal ganglia, which simultaneously innervate both eyes as well as give projections into peripheral nerves. It is suggested that these neurons can perform function of integration of sensor signals and, on its base, regulate photosensitivity of retina as well as activity of peripheral organs. There is established the presence of bilateral connections of the mollusc eye with cells of pedal ganglia and statocysts, which seems to be the structural basis of manifestation of the known behavior forms associated with stimulation of visual inputs of the studied gastropod molluscs.

[Retina mediators in fresh-water mollusc Lymnaeae stagnalis].

Retrograde staining of the Lymnaeae stagnalis retina with neurobiotin has shown that most photoreceptor cells send axons to optic nerve without intermediate contacts. A part of these photoreceptors have immunireactivity to glutamate that possibly provides synaptic transmission of visual signal to central neurons. Other photoreceptors stained through optic nerve seem to have different transmitter systems. In some retina cell, but not in optic nerve fibers, immunoreactivity to pigment-dispersing hormone has been revealed. In tissues surrounding the eye cup numerous serotonin-containing fibers are present, a part of them penetrating the retina basal layer. Some of them belong to central neurons responsible for efferent innervation of the pond snail eye. It is suggested that the serotoninergic innervation as well as the cell containing the pigment-dispersing hormone are included in the mechanism of regulation of light sensitivity of the mollusc eye.

[Is it possible to train Achatina fulica using visual stimulation?]. / Mozhno li obuchat' Achatina fulica, primeniaia zritel'nuiu stimuliatsiiu?

The conditioned behavior to visual stimuli was obtained in Achatina fulica mollusk on the basis of its negative phototaxis. Directional moving of snails toward black cards was accompanied by the negative unconditioned stimulation (electric current). Learning was expressed in a statistically significant decrease in locomotor activity of animals and decrease in the rate of preference of sections with black cards. Learning developed within two daily training sessions with 30 trials in each of them. Learning traces were observed as defensive behavior at least during a month after reinforcement elimination.

[The pharyngeal beta-hemolytic streptococcal carrier state among blood donors]. / Glotochnoe nositel'stvo beta-gemoliticheskikh streptokokkov sredi donorov krovi.

459 blood donors aged 18-50 years were examined in 1987-1988 in Moscow. Among them, carrier state with respect to beta-hemolytic streptococci was detected in 107 donors (23.3%). The number of carriers gradually decreased with the increase of age of the examined donors. Group C streptococci occurred least of all (6.9%). Group A beta-hemolytic streptococci were isolated in 16.7% of the carriers. The isolation rate of streptococci from blood achieved its maximum in autumn and winter months and did not depend on preceding diseases, unhealthy working conditions, the rhesus factor and, with the exception of group A streptococci, the blood group. Among tonsillectomized donors carrier state with respect to beta-hemolytic streptococci occurred 2.2 times less frequently than among donors who had not undergone tonsillectomy. Carrier state with respect to beta-hemolytic streptococci was accompanied by higher levels of salivary sIgA antibodies to polysaccharide A, serum antibodies to polysaccharide A and circulating polysaccharide A. All beta-hemolytic streptococci were sensitive to erythromycin. All groups of streptococci showed the highest percentage of cultures resistant to gentamicin and tetracycline. In 100% of cases group A streptococci were sensitive to benzylpenicillin, methicillin, ampicillin, erythromycin and lincomycin.

[The production of erythrogenic toxin and the epidemic process in respiratory streptococcal infection]. / Produktsiia éritrogennogo toksina i épidemicheskii protsess respiratornoi streptokokkovoi infektsii.

The capacity of Streptococcus pyogenes, isolated from clinically healthy children in a large organized group, for producing erythrogenic toxin A, B and C was studied. The dynamics of toxin production was compared with changes in the levels of morbidity and carrier state, as well as with some characteristics of the interaction between the populations of the infective agent and the host by such values as virulence and susceptibility. Similarity in the dynamics of the parameters under study was noted. The seasonal dynamics of characteristics which determined the capacity for toxin production significantly influenced the levels and one year morbidity dynamics with respiratory streptococcal infection. The study demonstrated the information value of the characteristics of toxin production for understanding both the interval mechanisms of the epidemic process and the influence of the external ones on subsequent epidemic situation.

[An explosive outbreak of respiratory streptococcal infection with a droplet transmission mechanism]. / Eksplozivnaia vspyshka respiratornoi streptokokkovoi infektsii s kapel'nym mekhanizmom peredachi.

The data obtained in the study of an explosive outbreak of acute respiratory diseases, tonsillitis and scarlet fever in one of schools in Moscow have made it possible to exclude the alimentary mechanism of its development and to demonstrate the role of the droplet mechanism of transmission in the appearance of its outbreak. The epidemiological analysis of the outbreak has permitted the formulation of the hypothesis on the conditions of the formation and spread of the epidemic variant of the infective agent; this hypothesis corresponds to the available data in literature on the qualitative changes of the infective agent in the course of the epidemic process. The study has shown that the prophylaxis of the explosive outbreaks of respiratory streptococcal infections must be ensured by the system of epidemiological surveillance with timely intervention into the epidemiological process at its early stages.

[The epidemic process of an acute streptococcal respiratory infection in large organized collectives of children]. / Epidemicheskii protsess ostroi respiratornoi streptokokkovoi infektsii v krupnykh detskikh organizovannykh kollektivakh.

The study of the specific features of the development of the epidemic process of scarlet fever, tonsillitis, and acute respiratory diseases (ARD) in two large organized groups of children revealed the presence of some differences which depended on the character of prophylactic measures taken in these groups. Thus, in the absence of prophylaxis with bicillin a pronounced increase in the level of carriership, accompanied by an increase in the infective capacity of carriers, was noted. This resulted in a high level and unfavorable dynamics of morbidity in scarlet fever, tonsillitis, and ARD. On the contrary, the use of prophylaxis with bicillin ensured the stability of the level of carriership, while the infective capacity of carriers was not pronounced. At the same time a rise in ARD morbidity was insignificant, and morbidity in scarlet fever and tonsillitis was reduced to nil.

[Age factor in eye regeneration of the gastropod mollusk Achatina fulica]. / Vozrastnoi faktor v regeneratsii glaza briukhonogogo molliuska Achatina fulica.

The dependence of the ability to regenerate the eye on the age of experimental animals was studied in the snail Achatina fulica. The degree of regeneration was estimated by light-microscopic and electrophysiological methods and by analyzing the motor response to visual stimuli. In older age groups, the number of regenerated eye-bearing tentacles decreased, whereas the period of regeneration increased. The regenerated eyes of the snails operated at the age of more than two months remained smaller than normal eyes even after six months. Regeneration of the distal part of the optic nerve was observed, and the regenerated eyes recovered the ability to respond to stimulation by light. In the electroretinogram, the responses of the regenerated eye, compared to the control, were characterised by a lower amplitude and longer repolarization and refractory periods. Manifestations of the motor response to visual stimuli in the young snails with regenerating eyes could be regarded as evidence for the recovery of connection between the organ of sight and the central ganglia.

[Antibiotic sensitivity of streptococci of the A, B, C and G serogroups isolated in 1987-1990]. / Chuvstvitel'nost' k antibiotikam streptokokkov serologicheskikh grupp A, B, C, i G, vydelennykh v 1987-1990gg.

Antibiotic susceptibility of 1114 cultures of beta-hemolytic streptococci belonging to serogroups A, B, C and G was tested. The cultures were isolated from healthy and diseased children and adults. Group A, C and G streptococci were shown to be highly susceptible to beta-lactams, erythromycin, lincomycin, chloramphenicol and ristomycin. Erythromycin, lincomycin, ristomycin and ampicillin (a beta-lactam) proved to be the most active antibiotics against group B streptococci. Streptococci of the four groups had low susceptibility to tetracycline and especially gentamicin. The different antibiotic susceptibility of the streptococcal cultures isolated from the diseased and healthy children and adults is discussed.

[Respiratory aid to patients with severe forms of suppurative meningitis]. / Respiratornaia pomoshch' bol'nym tiazhelymi formami gnoinykh meningitov.

The severity of acute respiratory failure (ARF) in patients with purulent meningitis (PM) depends on the severity of consciousness disorders. ARF is most expressed in comatose patients, whereas in PM involving no consciousness disorders there were no changes of the gaseous composition of the blood or acid-base status. After forced ventilation of the lungs is started, gaseous composition of the blood normalizes. Timely active respiratory care decreased by half the mortality in this patient population, this indicating that such patients are to be treated in intensive care wards for timely correction of disordered vital functions.

[The biochemical and immunological indices in the rehabilitation period of the victims of the accident on the Komsomolets atomic submarine]. / Biokhimicheskie i immunologicheskie pokazateli v reabilitatsionnom periode u postradavshikh v rezul'tate avarii atomnoi podvodnoi lodki "Komsomolets".

Biochemical and immunological indexes of peripheral blood were compiled in military sanatorium "Divnomorskoe" in seamen who have suffered from general supercooling in the result of "Komsomolets" atomic submarine breakdown. The patients had the symptoms of metabolic disturbance, immunodepression, a great concentration of proteins in acute phase and activity of MB-fraction of creatine phosphokinase. Immunodepression after the general supercooling was mainly conditioned by oppression of differentiation, metabolic changes and functional activity of T-lymphocytes. A course of immunocorrective therapy was employed using "thymogen"--synthetic peptide of thymus. In the process of rehabilitation there was a gradual functional recovery, normalization of metabolism and immunological indexes.