نتایج جستجو برای: polymorph crystalline silica

تعداد نتایج: 77663  

Journal: :The Annals of occupational hygiene 2014
Diane L Radnoff Michelle K Kutz

Exposure to respirable crystalline silica is a hazard common to many industries in Alberta but particularly so in abrasive blasting. Alberta occupational health and safety legislation requires the consideration of silica substitutes when conducting abrasive blasting, where reasonably practicable. In this study, exposure to crystalline silica during abrasive blasting was evaluated when both sili...

Journal: :Medycyna pracy 2014
Aleksandra Maciejewska

Crystalline silica is commonly found in the work environment. Possible health effects of occupational exposure continue to be the subject of extensive research. The aim of this paper was to analyze the recent findings concerning the health effects of exposure to crystalline silica, taking into account different levels of exposure. This work is based on the relevant information from the papers r...

2006
S. J. Ghan L. R. Leung

Figure 1 summarizes the various cloud variables and their interactions. Precipitating cloud species are distinguished from non-precipitating species, and the liquid phase is distinguished from the ice phase. The size of the nonprecipitating cloud particles (which influences both the cloud radiative properties and the conversion of nonprecipitating cloud species to precipitating species) is dete...

2012

Silica, or silicon dioxide (SiO2), is a group IV metal oxide, which naturally occurs in both crystalline and amorphous forms (i.e. polymorphic; NTP, 2005). The various forms of crystalline silica are: α-quartz, β-quartz, α-tridymite, β-tridymite, α-cristobalite, β-cristobalite, keatite, coesite, stishovite, and moganite (NIOSH, 2002). The most abundant form of silica is α-quartz, and the term q...

Journal: :iranian journal of public health 0
ali omidianidost mehdi ghasemkhani hossein kakooei seyed jamaled­din shahtaheri masud ghanbari

background: the term crystallized silica refers to the crystallized form of sio 2 and quartz, the most frequency composition in the earth’s crust that can cause silicosis and lung cancer through occupational exposure and inhalation of its large quantities. methods: occupational exposure of workers in pakdasht, iran, in 2011 was investigated in four different casting processes in small foundries...

2012

Silica, or silicon dioxide (SiO2), is a group IV metal oxide, which naturally occurs in both crystalline and amorphous forms (i.e. polymorphic; NTP, 2005). The various forms of crystalline silica are: α-quartz, β-quartz, α-tridymite, β-tridymite, α-cristobalite, β-cristobalite, keatite, coesite, stishovite, and moganite (NIOSH, 2002). The most abundant form of silica is α-quartz, and the term q...

2016
Chao Li Sitong Du Yiping Lu Xiaowei Lu Fangwei Liu Ying Chen Dong Weng Jie Chen

Long term pulmonary exposure to crystalline silica leads to silicosis that manifests progressive interstitial fibrosis, eventually leading to respiratory failure and death. Despite efforts to eliminate silicosis, clinical cases continue to occur in both developing and developed countries. The exact mechanisms of crystalline silica-induced pulmonary fibrosis remain elusive. Herein, we find that ...

اسلامی, شهرام, محمدیان , محمود , رکنی, محمد, فاضلی, ابوالقاسم ,

Abstract Background and purpose: Workers' exposure to respirable silica particles especially free crystalline silica in workplace could result in some dangerous diseases such as silicosis or lung fibrosis. This study was carried out to evaluate the workers' exposure to free crystalline silica particles in some industries using the infrared spectrophotometery method. Materials and methods: I...

Journal: :The European respiratory journal 1991
J C Pairon P Brochard M C Jaurand J Bignon

The role of crystalline silica in lung cancer has long been the subject of controversy. In this article, we review the main experimental and epidemiological studies dealing with this problem. Some evidence for a genotoxic potential of crystalline silica has been obtained in the rare in vitro studies published to date. In vivo studies have shown that crystalline silica is carcinogenic in the rat...

2015

Breathing dust that contains respirable crystalline silica can lead to silicosis, a deadly lung disease. Respirable dust is that fraction of the aerosol that is small enough to reach the deeper, gas-exchange regions of the lungs. No effective treatment exists for silicosis, but it can be prevented by controlling workers’ exposures to dust containing crystalline silica. Exposure to crystalline s...

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