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A radioisotope method was devised to study bacterial respiratory reduction of arsenate in sediments. The following two arsenic-rich soda lakes in California were chosen for comparison on the basis of their different salinities: Mono Lake (∼90 g/liter) and Searles Lake (∼340 g/liter). Profiles of arsenate reduction and sulfate reduction were constructed for both lakes. Reduction of [ 73 As]arsenate occurred at all depth intervals in the cores from Mono Lake (rate constant [ k ] = 0.103 to 0.04 h −1 ) and Searles Lake ( k = 0.012 to 0.002 h −1 ), and the highest activities occurred in the top sections of each core. In contrast, [ 35 S]sulfate reduction was measurable in Mono Lake ( k = 7.6 ×10 4 to 3.2 × 10 −6 h −1 ) but not in Searles Lake. Sediment DNA was extracted, PCR amplified, and separated by denaturing gradient gel electrophoresis (DGGE) to obtain phylogenetic markers (i.e., 16S rRNA genes) and a partial functional gene for dissimilatory arsenate reduction ( arrA ). The amplified arrA gene product showed a similar trend in both lakes; the signal was strongest in surface sediments and decreased to undetectable levels deeper in the sediments. More arrA gene signal was observed in Mono Lake and was detectable at a greater depth, despite the higher arsenate reduction activity observed in Searles Lake. A partial sequence (about 900 bp) was obtained for a clone (SLAS-3) that matched the dominant DGGE band found in deeper parts of the Searles Lake sample (below 3 cm), and this clone was found to be closely related to SLAS-1, a novel extremophilic arsenate respirer previously cultivated from Searles Lake.

The system CaO-SiO 2 -Fe 2 O 3 serves as a useful base in examining the nature of glasses and mineral species found both in oxidized steelmaking slag and in glasses made using precipitator or baghouse dusts from electric are steelmaking furnaces. A study has demonstrated that by oxidizing steelmaking slag, normally containing Fe and FeO, to the higher oxidation state, Fe 2 O 3 , the slag has the potential to form both crystalline and glassy species which have cementitious properties. A second study has shown that dusts with high Fe 2 O 3 contents and small percentages of hazardous heavy metals can be converted to glassy or crystalline silicates with enhanced leaching resistance. Steel slag has limited cementitious properties due to both a lack of tricalcium silicate and the presence of wustite solid solutions as a predominant mineral phase. By oxidizing the slag, ferrite phases which are cementitious can be formed. The effectiveness of these phases as cements can also be enhanced by rapid quenching to form a predominantly glass structure. The phases found can be compared to the phases and glasses found in common cementitious materials such as Portland cement and granulated blast furnace slag using the CaO-SiO 2 -Fe 2 O 3 system. Steelmaking dusts containing zinc, lead, cadmium and chromium are an environmental problem because of the leaching of these heavy metals, particularly in acid rain. By melting these dusts in a fifty percent SiO 2 matrix and quenching in water, it is possible to form glasses, occasionally containing some crystalline species, which have high resistance to acid leaching

The purpose of this study was to determine whether use of a 24-hour personal emergency response system (PERS) might be associated with selected hospital utilization rates among community-residing users. Utilization rates of 106 patients were reviewed for 1 year before and 1 year after enrollment in the PERS. Self-paired analyses were conducted on number of visits to an emergency department (ED), number of hospital inpatient admissions, and number of inpatient days. During the 1-year follow-up period, those subscribers using the PERS had a statistically significant decrease in per person hospital admissions and inpatient days. No significant differences occurred in ED visits. When indicated, a PERS may be an appropriate environmental prescription.

Forty-six raw milk samples were analyzed for plate counts at 32 C by eight different laboratories; each using three mixing procedures for the initial dilution. These were: five inversions in a 5 sec period, 15 inversions in a 15 sec period, and the “standard” method of twenty-five, 1 ft long, vertical cycles in a 7 sec period. The standard method gave the highest bacterial counts (71.1 × 103/ml average) the 15-15 method was second highest (60.4 × 103/ml average) and the 5-5 method was lowest (57.8 × 103/ml average). The standard method gave significantly higher (P Tests of reproducibility (pooled average variances for each method) did not show any significant differences between mixing methods. There were significant differences in reproducibility between laboratories. There was evidence of interaction between mixing methods by samples and mixing methods by investigators.

Water or bromotrifluoromethane content required in propellant Aerozine-50 /A-50/ spill to inert against ignition in air, considering fire extinguishment

A technique for experimentally determining the hydrodynamic particle velocity in gaseous detonations is described. The technique is based on the magnetohydrodynamic interaction of the ionized reactants and products with an externally applied magnetic field. Particle velocities in 2H2+O2 and 2H2+2O2 detonations were found to be 1.3 mm/μsec and 0.96 mm/μsec, which are in good agreement with those calculated from detonation rate and pressure.