نتایج جستجو برای: beryllium
تعداد نتایج: 2590 فیلتر نتایج به سال:
We present the first detection of beryllium in two turnoff stars of the old, metal-poor globular cluster NGC 6397. The beryllium lines are clearly detected and we determine a mean beryllium abundance of log(Be/H)= −12.35± 0.2. The beryllium abundance is very similar to that of field stars of similar Fe content. We interpret the beryllium abundance observed as the result of primary spallation of...
Chronic beryllium disease (CBD) begins as a sensitizing cell-mediated immune response to beryllium antigen that progresses to granulomatous lung disease. Previous studies demonstrated the involvement of proinflammatory cytokines in the disease process, but the pattern and regulation of cytokine release is unknown. Using bronchoalveolar lavage (BAL) cells from CBD patients in short-term tissue c...
OBJECTIVES Chronic beryllium disease (CBD) shares many of its characteristics with sarcoidosis and is often treated with corticosteroids. There is limited available literature regarding the effect of long-term corticosteroid therapy on the natural history of CBD. METHODS AND MATERIALS We conducted an observational retrospective study of six patients with CBD who received prolonged corticoster...
We herein investigate the interaction of beryllium with a graphene sheet and in a bilayer of graphite by means of periodic DFT calculations. In all cases, we find the beryllium atoms to be more weakly bonded on graphene than in the bilayer. Be2 forms both magnetic and non-magnetic structures on graphene depending on the geometrical configuration of adsorption. We find the stability of the Be/bi...
Epidemiological studies have reported process-specific elevated prevalence of beryllium sensitization (BeS) and chronic beryllium disease (CBD) among workers. However, exposure-response relationships have been inconsistent, possibly due to incomplete characterization of many biologically relevant aspects of exposure, including particle size. In 1999, two surveys were conducted 3-5 months apart ...
BACKGROUND Isolated cases of allergic contact dermatitis, gingivitis and stomatitis caused by beryllium have been previously reported. We have been able to study a series of 12 patients with patch test reactions to beryllium chloride. OBJECTIVES The study was aimed at defining the clinical and patch testing characteristics in this group of patients, and determining whether some were delayed e...
BACKGROUND Beryllium is known to be toxic to the lungs, causing beryllium lung disease and associated with increased lung cancer risk. Airborne beryllium exposures have been monitored since the 1940s. This study describes methods used to measure airborne beryllium concentrations and how historical measurements from a beryllium manufacturing plant were used to estimate workers' exposures in a lu...
Chronic beryllium disease (CBD) is caused by exposure to beryllium in the workplace, and it remains an important public health concern. Evidence suggests that CD4(+) T cells play a critical role in the development of this disease. Using intracellular cytokine staining, we found that the frequency of beryllium-specific CD4(+) T cells in the lungs (bronchoalveolar lavage) of 12 CBD patients range...
Chronic beryllium disease (CBD) is an exposure-related granulomatous disease mimicking sarcoidosis. Beryllium exposure-associated disease occurs mainly via inhalation, but skin may also be a source of sensitization. A 65-year-old male with a history of war-related shrapnel wounds was initially diagnosed with pulmonary sarcoidosis. Twenty years later, the possibility of a metal-related etiology ...
In this work, the Isfahan Miniature Neutron Source Reactor (MNSR) is first simulated using the WIMSD code, and its fuel burn-up after 7 years of operation ( when the reactor was revived by adding a 1.5 mm thick beryllium shim plate to the top of its core) and also after 14 years of operation (total operation time of the reactor) is calculated. The reactor is then simulated using the MCNP code,...
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