The oxidative corrosion of carbide inclusions at the surface of uranium metal during exposure to water vapour.

The reaction between uranium and water vapour has been well investigated, however discrepancies exist between the described kinetic laws, pressure dependence of the reaction rate constant and activation energies. Here this problem is looked at by examining the influence of impurities in the form of carbide inclusions on the reaction. Samples of uranium containing 600 ppm carbon were analysed during and after exposure to water vapour at 19 mbar pressure, in an environmental scanning electron microscope (ESEM) system. After water exposure, samples were analysed using secondary ion mass spectrometry (SIMS), focused ion beam (FIB) imaging and sectioning and transmission electron microscopy (TEM) with X-ray diffraction (micro-XRD). The results of the current study indicate that carbide particles on the surface of uranium readily react with water vapour to form voluminous UO(3) · xH(2)O growths at rates significantly faster than that of the metal. The observation may also have implications for previous experimental studies of uranium-water interactions, where the presence of differing levels of undetected carbide may partly account for the discrepancies observed between datasets.

Comparison of acetate differential agar with sellers citrate-mannitol-agar.

A total of 245 isolates of Escherichia coli (paracolons) were employed in comparing the use of acetate differential agar (ADA) with the simple test described by Sellers to eliminate these organisms from consideration as enteric pathogens. At 18 hr after the media were inoculated, 83% of the isolates produced a positive citrate reaction on Sellers citrate-mannitol-agar (SCM) and 7% gave a positive reaction on ADA. At 24 hr, 92% of the cultures were positive on SCM versus 42% on ADA. At 48 hr, 244 (99.6%) of the isolates were positive on SCM, whereas a 72-hr incubation period was required for equal results with ADA. One isolate failed to grow on either medium.

Improved motility medium.

An improved motility medium which permits additional cultural characterization is described. Advantages include maximal motility due to a change in the physical state of the medium from solid to liquid at incubation temperatures, a definitive stab line, preservation of the stab line with nonmotile organisms, and visual delineation of culture motility. In addition, nitrate reduction, nitrogen gas production, and gelatin liquefaction may be demonstrated.

Effect of high oxygen concentration on virulence of Staphylococcus aureus.

Cultures of Staphylococcus aureus were agitated and treated with oxygen or air for a period of 29 days. At intervals of 1, 3, 9, 15, and 29 days, samples of washed cells were tested for coagulase activity and for abscess-producing ability. It was found that aeration with agitation initially increased abscess formation and that the increase was of the same magnitude for oxygen and air. Continued treatment beyond 1 day resulted in a progressive decrease in this activity which was more pronounced in the oxygenated cultures. Throughout the treatment, the bound coagulase activity remained constant. Thus, there appeared to be no quantitative relationship of coagulase titer with virulence as expressed by lesion formation.

Mortality of altitude-exposed mice infected with Pasteurella tularensis.

The influence of reduced barometric pressure equivalent to an altitude of 18,000 ft (5,486 m) on the susceptibility of mice to tularemia was investigated by exposing groups of animals to the test environment before, after, or before and after intraperitoneal inoculation of 225 colony-forming units of Pasteurella tularensis. Similarly infected control animals were not exposed to the experimental environment. Two measurements of mortality were employed: (i) the day on which 50% of the mice were dead; and (ii) the number of dead mice on the 8th day. Continuous altitude exposure for 14 days prior to infection had no effect on host susceptibility but exposure after infection significantly increased mortality (P < 0.001).

Effect of environment on staphylococcal lesions in mice.

The influence of reduced barometric pressure on the development and healing of staphylococcal skin lesions in mice was investigated by exposing groups of animals to the test environment before, after, or before and after subcutaneous inoculation with 3.5 x 10 colony-forming units of a phage type 80 strain of Staphylococcus aureus. Similarly infected control animals were not exposed to the experimental environment. The results indicate that the lesions which developed in mice exposed to the test environment prior to infectious challenge were larger and healed at a slower rate than those in mice maintained at ground level before infection. Exposure after inoculation produced no demonstrable effect in the size or healing rate of the experimental lesions.

Rubella screening and vaccination program for US Air Force trainees: an analysis of findings.

A preventive medicine program of rubella control for trainees at the Air Force Military Training Center, Lackland AFB, Texas, was begun in October 1977. Incoming trainees were screened for rubella susceptibility, and female trainees were additionally screened for pregnancy. During the period October 1977 to December 1978, an overall rubella susceptibility rate of 17.3 per cent was determined for 71,387 trainees entering basic training. Flights (50 persons each) to which these trainees are assigned varied widely in susceptibility from 0.0-47.7 per cent. Comparisons of susceptibility rates for trainees for for geographic areas and states indicated the highest overall percentage of susceptibles were from the Pacific geographic area with California showing the highest susceptibility (24.5 per cent). Race specific susceptibility rates were found to differ significantly between Whites and Blacks, 17.6 vs 14.8 per cent, respectively. The immunization program was effective as judged by a dampening of the incidence of clinical rubella at the basic training center and at other secondary training centers.

Effect of interferon inducers and interferon on bacterial infections.

The effect of interferon inducers and exogenous L-cell interferon on the infection of mice by Pasteurella tularensis or Diplococcus pneumoniae was investigated. The results indicate that the degree of protection is dependent on the type of inducer used. A variety of defense mechanisms with limited nonspecific activity appear to be involved.

Hypercalcaemia in osteogenesis imperfecta treated with pamidronate.

The response to the bisphosphonate, pamidronate, is reported in a child with osteogenesis imperfecta who had recurrent symptomatic hypercalcaemia after immobilisation following fractures. Oral clodronate was effective in the prevention of immobilisation hypercalcaemia in the same child. The bisphosphonates may have other roles in osteogenesis imperfecta by decreasing bone turnover.