RESUMO
A radiochemically pure solution of 91Y was produced by the thermal neutron fission of 235U followed by successive chemical separations to remove fission product impurities. The gamma emission rate of the 91Y 1205 keV gamma was measured using multiple high purity germanium gamma spectrometers previously calibrated for counting efficiency using a certificated mixed nuclide gamma standard. The activity concentration of the 91Y was subsequently standardised by liquid scintillation counting. From the combination the activity concentration and gamma emission intensity, the absolute intensity of the 1205 keV gamma emission was derived as 0.2297(39)%. This data agrees within the quoted uncertainties with the absolute intensity of 0.26(4)% published in nuclear data sheets A=91 (Baglin, 2013), but reduces the uncertainty by an order of magnitude.
RESUMO
Occupational exposure to asbestos has been epidemiologically associated with carcinoma of the larynx; however, no search for or quantitation of laryngeal asbestos bodies has been performed. This report concerns an autopsy study of five patients with occupational asbestos exposure and proven asbestos-associated pulmonary disease in whom histologic sections of the larynx were examined and a digestion-concentration technique was used to isolate and quantitate the asbestos bodies in the remaining laryngeal tissues. No dysplastic epithelial changes were present in the mucosa. Asbestos bodies were recovered from two of the five larynges but from none of ten larynges obtained from autopsy controls.
