Biomedical subjects
Publications and source records attributed to M Corn.
The DDT associated with samples of airborne particulates was measured by gas chromatography. Because of possible vaporization of DDT during sampling, concentrations reported represent minimum values but demonstrate that DDT can be present in an urban atmosphere that is distant from any large-scale agricultural activity.
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There has been little past emphasis on determining the impact of control technologies on health. Compliance with legally mandated standards has received the greatest emphasis, certainly since passage of the OSHA of 1970. Risk assessment focuses on needed data to estimate risk and can be used for estimates of workplace impacts before and after adoption of control technologies. Two possible approaches to workplace improvements are suggested for estimating impacts on worker health. Persons removed from risk can be used where workers' exposures to hazardous agents are reduced from above to below a TLV. Second, for carcinogens the percent reduction in exposure can be used as a surrogate for reduction in future cancer incidence. Both measures suffer from a host of assumptions required by the user. There may be better measures for estimating today the reductions in chronic disease which control technologies will bring about. These measures are desperately needed to establish priorities and to guide installation of control technologies. Finally, research in control technologies is needed to improve effectiveness and to lower costs. However, it is widely accepted by engineers in this field that while improved methods are always welcome, current available technologies are under-utilized in practice.
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The two tantalum powders, "5mu" and "1.4mu", available from Fansteel Metals, are characterized with respect to particle size. Results show that these powders cannot be used directly for tantalum bronchography, but require fractionation to achieve a range of sizes for effective use in tantalum bronchography. This task can be accomplished with the BAHCO Micro Particle Classifier. The powder designated "1.4mu" is superior to the "5mu" powder because about 60% by weight can be salvaged by separation for use in bronchography, compared to only 7% by weight of the "5mu" powder. Theoretical considerations of particle deposition in the human respiratory tract indicate that the material obtained with throttle 16 of the BAHCO is best suited for tantalum bronchography. The dust generator is a good tool to deliver a dust cloud into the lung. The generator can operate for approximately 2 1/2 hours before the brush of the brush feed must be replaced; a procedure taking about 10 min. Additional maintenance is unnecessary. The breathing resistance of 1.1 inch of water imposed by the generator system, and which has to be overcome by the patient, is judged acceptable. The bronchograms obtained by introducing tantalum dust for 10 min into an artificially ventilated dog lung were clear, with deposition heaviest at bifurcations. These results suggest that the generator should now be used for human bronchography.
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The 1999 debate of the American College of Medical Informatics focused on the proposition that medical informatics and nursing informatics are distinctive disciplines that require their own core curricula, training programs, and professional identities. Proponents of this position emphasized that informatics training, technology applications, and professional identities are closely tied to the activities of the health professionals they serve and that, as nursing and medicine differ, so do the corresponding efforts in information science and technology. Opponents of the proposition asserted that informatics is built on a re-usable and widely applicable set of methods that are common to all health science disciplines, and that "medical informatics" continues to be a useful name for a composite core discipline that should be studied by all students, regardless of their health profession orientation.
Measured airborne concentrations of asbestos are often unavailable to assess different epidemiologic estimates of past personal exposure levels or concentrations near specific operations involving handling asbestos. The purpose of this study was to assess the potential use of a laboratory study in estimating exposure to asbestos in operations that ceased for many years. The asbestos transfer operations were simulated by splitting and boxing 4.5-kg paper bags of chrysotile asbestos in an enclosed chamber ventilated at 28.2 air changes per hour (ACH). Two recirculation fans achieved chamber air mixing. The airborne concentration of asbestos fibers was determined by sampling air through membrane filters at a rate of 10 l/min and by analysing fibers by phase contrast optical microscopy to determine 15-min average airborne concentrations. Samplers were located at four equidistant locations from the operation. Opening a maximum of seven bags in 15 min was associated with an asbestos-in-air concentration of less than 2 x 10(-6) fibers/m3 (f/m3) in splitting open and boxing and less than 0.85 x 10(-6) f/m3 in boxing of pre-split bags. The measured airborne asbestos concentration exhibited a linear trend with the number of bags opened per 15 min. The empirical results were utilised to model fiber concentrations for various ventilation rates. It was concluded that the distribution of the operation within the workday and the ventilation rate are the two most important variables in the determination of the estimated time-weighted average concentration. Splitting open and boxing 32 bags of asbestos over an 8-h period at a rate of 4 bags/h over an 8-h period results in a calculated time-weighted average exposure of about 1 x 10(-6) f/m3 in a work space with 20 ACH and approximately 7 x 10(-6) f/m3 in a work space with 2 ACH. Splitting open and boxing at a rate of 12 bags/h for 2 h and 45 min yielded calculated concentrations less than one-half of the above mentioned values. These results should serve as a useful benchmark for epidemiologists concerned with the magnitude of exposure in historically dusty industrial tasks.
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