PubMed Health⌕ Search

Biomedical subjects

G L Hobby

Publications and source records attributed to G L Hobby.

At least 19 recordsLinked to original sources
PubMed1975

Ultraviolet-gas phase and -photocatalytic synthesis from CO and NH3.

The major photoproduct obtained on irradiation of gaseous NH3 and CO mixtures is ammonium cyanate; lesser amounts of urea, biurea, biuret semi-carbazide, formamide and cyanide were observed. The formation of the major gas phase photolysis product may be rationalized by the following reaction sequence: (see article). Urea is probably formed from NH4NCO in a thermal reaction while formamide may result from the disproportionation of NH2CO. Photocatalytic syntheses of 14C-urea, -formamide, and -formadehyde are effected by irradiation of 14CO and NH3 in the presence of Vycor, silica gel, or volcanic ash shale surfaces. These syntheses are catalyzed by ultraviolet wavelengths longer than those absorbed by the gaseous reactants. The syntheses are also effected when the surface material is first irradiated in the presence of CO followed by a dark incubation with NH3. Apparently, the initiating step is a light dependent formation of a reactive form of CO on the surface. A discussion is given on the possible contribution of these reactions to the abiotic synthesis of organic nitrogen compounds on Mars, on the primitive Earth and in interstellar space.

Ammonia↗
PubMed1973

Enumeration of tubercle bacilli in sputum of patients with pulmonary tuberculosis.

A method for precise microscopic enumeration of acid-fast bacilli in the sputum of patients with pulmonary tuberculosis is described. The total number of acid-fast bacilli and the number of culturable cell units of tubercle bacilli per milliliter of sputum were determined in 269 specimens from 28 patients collected prior to and/or during chemotherapy, to establish the usefulness of the procedure for evaluation of the effects of chemotherapy. Prior to or very early in the course of therapy, there was good agreement between microscopically and culturally measurable bacilli in 27 of 28 patients. Thereafter, there were systematic divergences in five patients and occasional divergences in most others. Yet, in general, in 20 of the 28 patients, the microscopically determined population provided a useful measure of the number of culturable tubercle bacilli present. Although the microscopic procedure does not allow species identification of mycobacteria or differentiation between viable and nonviable cells, it often provided, within hours rather than days or weeks, useful information on the residual burden of acid-fast bacilli in sputum during chemotherapy. The nature of the disease in those patients in whom microscopy failed to provide useful information is discussed.

Adolescent↗
PubMed1970

Measurement of CO(2) Assimilation in Soils: an Experiment for the Biological Exploration of Mars.

A method is described for the measurement of CO(2) assimilation by microorganisms in soils. A determination involves exposing soil to CO(2), pyrolyzing the exposed soil, trapping the organic pyrolysis products on a column of firebrick coated with CuO, combusting the trapped organics by heating, and measuring the radioactivity in the CO(2) produced in the combustion. The detection of significant levels of C in the trapped organic fraction appears to be an unambiguous indication of biological activity. The CO(2) which is adsorbed or exchanged into soils by nonbiological processes does not interfere. The method easily detects the CO(2) fixed by 10 to 10 algae after light exposure for 3 to 24 hr. Assimilation of C is also demonstrable in dark-exposed soils containing 10 to 10 heterotrophic bacteria. Possible applications of the method in the biological exploration of Mars are discussed.

Journal Article↗