Dielectron production in 12C+12C collisions at 2A GeV with the HADES spectrometer.

The invariant-mass spectrum of e+e- pairs produced in 12C+12C collisions at an incident energy of 2 GeV per nucleon has been measured for the first time. The measured pair production probabilities span over 5 orders of magnitude from the pi(0)-Dalitz to the rho/omega invariant-mass region. Dalitz decays of pi(0) and eta account for all the yield up to 0.

[Relaparotomy in the treatment of generalized postoperative peritonitis].

The results of treatment of 46 patients with postoperative peritonitis, caused by intestinal sutures incompetence (41.4%) and break of the abscess into the abdominal cavity (32.6%) are analysed.

[The effect of the professional activities of flight personnel on their tolerance for the rebreathing test].

The return breathing test (rerespiration) developed by the authors makes it possible to conduct testing on the efficiency of compensatory reactions and disclose the reserve capacities of cardiorespiratory system in pilots. 82 pilots were examined in the process of their professional activity. The major part can be subdivided into 3 groups with middle, good and high tolerance to rerespiration, having 1/3 of pilots under 30 years old a high tolerance to test.

[Informative value of rerespiration as a method for evaluating functional reserves of the cardiorespiratory system in modeling of some flight factors].

This article presents a study of the informative value of the recurrent breathing (rerespiration) method developed by the authors, for evaluating the functional status of the human body during recovery after exposure to noise and vibration, to piloting accelerations and head-down hypokinesis. It is shown that a 1.5-h exposure to noise and vibration increases tolerance to rerespiration, suggesting a stimulatory effect.

[Criteria of tolerance of the hypercapnia-hypoxia test].

Examination of 84 essentially healthy men, aged 19 to 34 years, by the rebreathing method showed that in various test subjects the reserve time prior to decompensation was in the range 5 to 9 min. A certain change was seen 1-2 min before termination of the test due to acute respiratory failure. This change included an increase in the minute respiration volume above 40 1/min and its relative increment by 10 1/min or over when compared to the preceding minute.

[Effect of the hypercapnic-hypoxic test on cardiovascular parameters in individuals with neurocirculatory dystonia].

Twenty healthy men and twelve patients with hypertensive type neurocirculatory dystonia belonging to the flying personnel were examined. They breathed a hypercapnic-hypoxia mixture formed during rebreathing in a closed circuit without a CO2 adsorber. In both groups this provocative test produced similar variations of most parameters under study.

[Use of central electroanalgesia to restore the body's functional state in motion sickness].

Central electroanalgesia (CEAN) is a technique that involves application of pulsating current to the central nervous system in order to enhance its tonicity recover autonomic equilibrium and to reduce parasympathetic cardiovascular reactions. In two experimental runs in which 9 volunteers participated the efficacy of CEAN in preventing motion sickness symptoms produced by Markaryan's test was studied. After two rotations repeated with a one-hour interval vestibular reactions persisted for 7-10 hours.

[Coronary blood flow function in patients with chronic postembolic pulmonary hypertension].

Variations in coronary blood flow and cardiac output were studied using dopplerography throughout rationed exercise in 16 patients with chronic postembolic pulmonary hypertension. All patients showed reduced coronary flow during exercise, an evidence of early signs of coronary insufficiency. A correlation was demonstrated between coronary flow disorders and the severity of pulmonary hypertension, the extent of pulmonary vascular bed lesion and right-ventricular hypertrophy.

[Potential for modelling the hemodynamic effects of weightlessness by exposure to increased pressure].

Venous and arterial circulation was investigated by simulating cephalad blood shifts generated by an exposure of test subjects (n = 15) to lower body positive pressure (+25 mm Hg) and head-down tilts (at -8 degrees and -15 degrees). At LBPP and tilt -15 degrees arterial pressure increased by 5-15%. During tilt -8 degrees jugular vein blood filling increased by 8-94% in the course of the first 3 hrs and then decreased reaching the baseline (horizontal position) level.

[Venous blood circulation in the crew of the Saliut-5 orbital station].

Studies of venous circulation were continued in the space crewmembers of the orbital station Salyut-5. New data which demonstrated again that weightlessness induced symptoms specifically assoicated with blood redistribution and pressure increase in the jugular veins were obtained. It is suggested to further the studies of venous circulation and regional hemodynamics aimed at determining the time and degree of human body adaptation to weightlessness.

[Dynamics of the venous circulation in the cosmonauts of the 2d "Saliut-4" expedition].

During the first month of the orbital flight the cosmonauts showed an increase in the blood pressure and filling in the jugular veins whereas during the second month they exhibited a decrease in these parameters below the preflight level. Throughout the mission the pressure in the pulmonary artery remained slightly increased. The time of contractions of the right heart changed.