SPACE CABIN ATMOSPHERE TRACE CONTAMINANTS AND THEIR POSSIBLE INFLUENCE ON VISUAL PARAMETERS

In the investigation of various factors which can adversely influence the proper functioning of the visual apparatus in the aerospace environment, the study of space-cabin atmosphere composition and contamination has been largely neglected. Visual effects of the more classical contaminants have been little investigated.

This paper discusses these contaminants as well as the effects of ozone on certain visual parameters, in view of the fact that under influence of solar and cosmic radiations ozone may be formed from liquid and gaseous oxygen supplies on board spacecraft. Based upon the observed physiological effects of small doses of positive and negative free air ions, it is hypothesized that, in the ionized state, some gaseous and volatile human metabolic waste products may have entirely different properties than they have in the ordinary state, and may affect vision. Until definitely proven otherwise, this possibility must be accepted and investigated.

Atmospheric Iodine Abates Smog Ozone

Traces of iodine in test samples of irradiated photochemical smog atmospheres either inhibit ozone formation or lower its concentration. Eye and respiratory irritation are reduced qualitatively. Iodine is more effective in suppressing ozone in a photochemical smog atmosphere than it is in purified air.

EFFECT OF OZONE ON SURVIVAL AND PERMEABILITY OF ESCHERICHIA COLI

Scott, D. B. McNair (University of Pennsylvania, Philadelphia) and E. C. Lesher . Effect of ozone on survival and permeability of Escherichia coli . J. Bacteriol. 85: 567–576. 1963.— Escherichia coli cultures in the logarithmic phase or resting were treated with various concentrations of ozone in saline solution. Approximately 2 × 10 7 molecules of ozone per bacterium killed 50% of the cells. Ozone caused leakage of cell content into the medium, and lysis of some cells. Low concentrations of ozone did not react with the glutathione within the cells, although reaction with glutathione in solution was immediate and stoichiometric. The effect on nucleic acid within the cells was to change the solubility and to cause the release of ultraviolet-absorbing material into the medium. Ozone attacked the ring structure of the base or the carbohydrate only when the substance was in the medium. Nucleic acids released into the medium were reabsorbed by cells which were not lysed. Viable cells resumed growth immediately, and grew at rates determined by the nutrients either added to the medium or which resulted from leakage and lysis of nonviable cells. It is postulated that the primary attack of ozone was on the cell wall or membrane of the bacteria, probably by reaction with the double bonds of lipids, and that leakage or lysis of the cells depended on the extent of that reaction.

Behavioral Method for Study of Pain in the Monkey

A behavioral method is described in which increasing intensities of electric shocks were applied to the gasserian ganglia of alert monkeys. The animals were trained to press a lever to regulate the shock level. "Pain thresholds" were thereby obtained, and these thresholds were modified by varying the shock duration and by administration of morphine.