نتایج جستجو برای: crystalline silica
تعداد نتایج: 75815 فیلتر نتایج به سال:
Infrared Spectrophotometry (IR) is now widely used to determine crystalline silica in industrial dust samples. Though the IR method has many advantages when dealing with respirable dust samples, some serious analytical errors are often caused by interference minerals contamination. These minerals have a characteristic absorption band corresponding in position to the analytical peak for crystall...
Silicosis is a preventable occupational lung disease caused by the inhalation of respirable crystalline silica dust and can progress to respiratory failure and death. No effective specific treatment for silicosis is available; patients are provided supportive care, and some patients may be considered for lung transplantation. Chronic silicosis can develop or progress even after occupational exp...
Acid-base properties of excipient surfaces have been studied by photoacoustic spectroscopy (PAS) in the visible absorption range using seven acid-base indicators. The acid strength (Ho) of each excipient was determined from the PA spectral patterns of the indicators. The Ho values of silica-alumina, silica-magnesia and crystalline cellulose were determined to be between 3.3 and -3 .0, between 4...
Anthracofibrosis, defined as bronchial luminal narrowing with black pigmentation of the overlying mucosa, has been attributed to tuberculosis. Three patients with anthracofibrosis without mycobacterial infection are described who had previous occupational exposure to mixed dusts. CT scans showed calcified hilar lymph nodes in two patients. Surgical biopsy in one patient and autopsy in another r...
Tridymite, a low-pressure, high-temperature (>870 °C) SiO2 polymorph, was detected in a drill sample of laminated mudstone (Buckskin) at Marias Pass in Gale crater, Mars, by the Chemistry and Mineralogy X-ray diffraction instrument onboard the Mars Science Laboratory rover Curiosity The tridymitic mudstone has ∼40 wt.% crystalline and ∼60 wt.% X-ray amorphous material and a bulk composition wit...
Background and Aim: Color match between prosthetic restorations and natural teeth is challenging in dentistry. The aim of the current study was to assess the effect of accelerated aging on color stability of two silica-based ceramics with leucite and lithium disilicate crystalline phases after glazing and polishing surface treatments. Materials and Methods: In this experimental study, 30 disc-...
Volcanic ash is a heterogeneous mineral dust that is typically composed of a mixture of amorphous (glass) and crystalline (mineral) fragments. It commonly contains an abundance of the crystalline silica (SiO2) polymorph cristobalite. Inhalation of crystalline silica can induce inflammation by stimulating the NLRP3 inflammasome, a cytosolic receptor complex that plays a critical role in driving ...
The contents of this report reflect the views of the authors who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Indiana Department of transportation. This report does not constitute a standard, specification or regulation. A section of road was constructed in Northeastern Indiana in the s...
Asbestos and silica are well-known fibrogenic dusts. However, there is no comprehensive understanding of the molecular and cellular events that lead to fibrosis as a consequence of asbestos or silica inhalation. Previous studies have shown that asbestos stimulates superoxide anion production in alveolar macrophages through the phospholipase C/protein kinase C pathway. In contrast, silica does n...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید