Biomedical subjects
Publications and source records attributed to M L Kohn.
The calibration of a Nucletron MicroSelectron High Dose Rate Remote Afterloader unit and the radiation survey around the facility is discussed. The radiation survey of the facility indicates that the use of an existing linear accelerator vault will provide adequate shielding. The methodologies for performing source calibration are presented.
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Aluminum, yttrium, copper, and R-filters were evaluated with respect to effective beam energy, entrance radiation exposure to the skin, x-ray tube loading, and the quality of resultant radiographs. Since all filters yielded acceptable radiographs, a figure of merit was developed to determine which filter delivered the lowest entrance radiation exposure for the lowest increase in x-ray tube loading. The figure of merit indicated that the best results were obtained with the 0.1-mm Cu filter with 2 mm Al at 60-105 kVp and with the 0.2-mm Cu filter with 2 mm Al at 105-120 kVp. Cu filters produced radiographs with quality comparable to that of R- or Y filters. Cu filters are inexpensive alternatives to rare-earth filters and yielded a reduction in radiation exposure with less x-ray tube loading.
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Epidemiological evidence clearly indicates an especially high rate of schizophrenia at the lowest social class levels of urban populations. The author suggests that this relationship between class and schizophrenia exists because the conditions of life experienced by people of lower social class position foster conceptions of social reality that are so limited and rigid as to impair their ability to deal resourcefully with the problematic and the stressful. Such impairment does not in itself result in schizophrenia; however, in conjunction with genetic vulnerability and great stress, it could be disabling.