نتایج جستجو برای: beryllium
تعداد نتایج: 2590 فیلتر نتایج به سال:
CONTEXT This review describes the health effects of beryllium exposure in the workplace and the environment. AIM To collate information on the consequences of occupational and environmental exposure to beryllium on physiological function and well being. MATERIALS AND METHODS The criteria used in the current review for selecting articles were adopted from proposed criteria in The Internation...
Occupational medicine physicians are frequently asked to establish cancer causation in patients with both workplace and non-workplace exposures. This is especially difficult in cases involving beryllium for which the data on human carcinogenicity are limited and controversial. In this report we present the case of a 73-year-old former technician at a government research facility who was recentl...
The properties of several point defects in hexagonal gallium nitride that can compensate beryllium shallow acceptors (BeGa) are calculated using the AIMPRO method based on local density functional theory. BeGa itself is predicted to have local vibrational modes ~LVM’s! very similar to magnesium acceptors. The highest frequency is about 663 cm. Consistent with other recent studies, we find that ...
Chronic beryllium disease (CBD) is caused by beryllium exposure and is characterized by granulomatous inflammation with accumulation of CD4+ T cells in the lung. We analyzed TCR beta-chain and alpha-chain genes expressed by these CD4+ T cells. In the lungs of individual patients, as well as among four of five CBD patients studied, different oligoclonal expansions within the Vbeta3 subset were f...
We have carried out a theoretical and experimental investigation of the beryllium K-edge soft x-ray absorption fine structure of beryllium compounds in the oxygen group, considering BeO, BeS, BeSe, and BeTe. Theoretical spectra are obtained ab initio, through many-body perturbation theory, by solving the Bethe-Salpeter equation (BSE), and by supercell calculations using the core-hole approximat...
We describe a silicon microstrip detector interleaved with segments of a beryllium oxide target which was used in the FOCUS photoproduction experiment at Fermilab. The detector was designed to improve the vertex resolution and to enhance the reconstruction efficiency of short-lived charm particles.
the effect of interstitial atoms upon portevin _ le chate1ier phenomena, are theoretically and experimentally investigated as a manifestation of the cottrell effect. in presence of substitutional atoms, because of their very smaller diffusion coefficient, the condition is more complicated. in this article the behaviour of substituflonal atoms in the beryllium and a few fe alloys, on portevin-le...
Introduction: Arsenic, beryllium, cadmium and nickel have been associated with the prevalence of diabetes mellitus in populations exposed to these elements. However, diabetes mortality has not been evaluated. This ecological study correlated airborne concentrations of these metals with diabetes mortality in North Carolina counties. Methods: County level data were extracted from the 2000 US Cens...
The composition of aqueous fluoroberyllate solutions has been studied by 9Be and l9F NMR spectroscopy for various ratios of the beryllium and fluorine concentrations, and at different pH values. The equilibrium constants have been determined for the ligand exchange processes, which involve the species [Be(OH2)4]2+, [BeF(OH2)3]+, [BeF2(OH2)2], [BeF3(OH2)]_ , and [BeFzi]2 . These equilibria are s...
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