This article examines the history of human exposure to silica, the second most common element on earth, to explore the problem of categorizing substances for regulatory purposes and the role interest groups play in developing policy. The regulatory history of silica teaches three important lessons: First, the most compelling account of the cycle of action and inaction on the part of regulators ...

Adsorption onto silica-based high surface area carriers is a long known method of improvement drug dissolution rate, which has been described in early 1970s [1]. Porous silica has many silanol groups on its surface and can be used as pharmaceutical excipient, since it is regarded nontoxic after oral application. Due to its porous structure and large specific surface area, porous silica has a gr...

Application of Arc-GIS for Zoning Occupational Exposure Levels to Respirable Crystalline Silica in Crushing Factories

Elevated temperature synthesis has been used to generate virtually defect free SiO2 sheathed crystalline silicon nanowires and silica (SiO2) nanospheres which can be agglomerated to wire-like configurations impregnated with crystalline silicon. The SiO2 passivated ~sheathed! crystalline silicon nanowires, generated with a modified approach using a heated Si–SiO2 mix, with their axes parallel to...

BACKGROUND A work force based case-control study of lung cancer was performed in non-silicotic subjects exposed to crystalline silica to investigate the association between silica dust and lung cancer excluding the influence of silicosis. METHODS Two hundred and forty seven patients with lung cancer and 795 control subjects were enrolled, all of whom had been employed in the German stone, qua...

Crystalline silica exposure can result in pulmonary fibrosis, where the pulmonary macrophage is key as a result of its ability to react to silica particles. In the mouse silicosis model, there is initial Th1-type inflammation, characterized by TNFand IFN. Previous studies determined that Th2 mediators (i.e., IL-13) are vital to development of pulmonary fibrosis. The present study, using in vivo...

Previous studies suggest that tumor necrosis factor alpha (TNF-alpha) and the TNFRI (p55) and TNFRRII (p75) receptors mediate the pulmonary fibrotic response to silica. In order to further define the role of the TNFRI (p55) receptor in induction of profibrotic chemokines by low-dose silica/crystalline silica (50 micro g/50 micro l/mouse) or control diluent saline was instilled into the trachea ...