نتایج جستجو برای: beryllium compounds
تعداد نتایج: 229129 فیلتر نتایج به سال:
Controlling beryllium inhalation exposures to comply with regulatory levels (2 micro g m(-3) of air) does not appear to prevent beryllium sensitization and chronic beryllium disease (CBD). Additionally, it has proven difficult to establish a clear inhalation exposure-response relationship for beryllium sensitization and CBD. Thus, skin may be an important route of exposure that leads to berylli...
DURING an investigation of the toxic action of beryllium salts on experimental animals a histochemical test was developed to provide information on the distribution and site of action of beryllium. The technique is reported as an example of the application of chemical methods to histological problems. The reactions of beryllium salts with dyes of the triarylmethane series have been studied by A...
Copper beryllium alloys are the most commonly used form of beryllium; however, there have been few studies assessing occupational exposure in facilities that worked exclusively with this alloy versus those where pure metal or beryllium oxide may also have been present. In this paper, we evaluated the airborne beryllium concentrations at a machining plant using historical industrial hygiene samp...
To investigate the effects of short-term exposure of beryllium on the human immune system, the proportion of T-lymphocytes such as CD3+, CD4+, CD8+, CD95, and NK cells, andthe proportion of B cells and TNFα level in peripheral blood and immunoglobulins in the serum of 43 exposed workers and 34 healthy control subjects were studied. External exposure to beryllium was measured by atomic absorptio...
Beryllium exposure can lead to the development of beryllium-specific CD4+ T cells and chronic beryllium disease (CBD), which is characterized by the presence of lung granulomas and a CD4+ T cell alveolitis. Studies have documented the presence of proliferating and cytokine-secreting CD4+ T cells in blood of CBD patients after beryllium stimulation. However, some patients were noted to have cyto...
Beryllium metal has physical properties that make its use essential for very specific applications, such as medical diagnostics, nuclear/fusion reactors and aerospace applications. Because of the widespread human exposure to beryllium metals and the discrepancy of the genotoxic results in the reported literature, detail assessments of the genetic damage of beryllium are warranted. Mice exposed ...
Power plant dust is believed to be the main source of the increased presence of the element beryllium in the environment which has been detected in the atmospheric air, surface waters, groundwater, soil, food, and cigarette smoke. In humans, beryllium absorption occurs mainly via the respiratory system. The pharyngeal tonsils are located on the roof of the nasopharynx and are in direct contact ...
Beryllium exposure in the workplace can result in chronic beryllium disease, a granulomatous lung disorder characterized by CD4(+) T cell alveolitis and progressive lung fibrosis. A large number of the CD4(+) T cells recruited to the lung in chronic beryllium disease recognize beryllium in an Ag-specific manner and express Th1-type cytokines following T cell activation. Beryllium-responsive CD4...
The purpose of this study was to determine how two types of sampling data could be used for an exposure assessment in a beryllium shop at the Department of Energy's Rocky Flats Plant. Beryllium exposure was assessed via fixed airhead (FAH) sampling, in which the filter cassette was affixed to the machine, generally within a few feet of the worker's breathing zone. Approximately 500,000 FAH samp...
The synthesis of a linear beryllium bis(diazaborolyl) compound featuring the first non-cluster bond between boron and beryllium has been achieved through the reaction of Yamashita's lithium diazaborolide and BeCl2. In accord with the established chemistry of beryllium, the bonding is polar covalent in character, as determined by structural and spectroscopic analysis, as well as reactivity studies.
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