نتایج جستجو برای: crystalline silica

تعداد نتایج: 75815  

Introduction: The silica crushing is a process based on crushing, screening and, granulation of various types of silica rocks. The inhalation of silica dust leads to silicosis by causing irreversible fibrosis in lung tissue. The crystalline silica is classified as a human carcinogenic (group I) by the IARC. Azandarian region is one of the largest silica production units in Iran with 40 silica c...

Journal: :Toxicological sciences : an official journal of the Society of Toxicology 2010
Giulia Giordano Sybille van den Brûle Sandra Lo Re Perrine Triqueneaux Francine Uwambayinema Yousof Yakoub Isabelle Couillin Bernhard Ryffel Thomas Michiels Jean-Christophe Renauld Dominique Lison François Huaux

Lung disorders induced by inhaled inorganic particles such as crystalline silica are characterized by chronic inflammation and pulmonary fibrosis. Here, we demonstrate the importance of type I interferon (IFN) in the development of crystalline silica-induced lung inflammation in mice, revealing that viruses and inorganic particles share similar signaling pathways. We found that instillation of ...

Journal: :Industrial health 2004
Yasushi Shinohara Norihiko Kohyama

The quantities of two forms of crystalline silica, tridymite and cristobalite, in heated rice husk ash (RHA) samples were determined by X-ray diffraction (XRD) and chemical methods. Two RHA samples, containing 93% SiO2 and 2-3% K2O, were prepared from charcoaled rice husk products and heated to above 900 degrees C. The crystalline silica made up over 60-80% of the total silica in the heated RHA...

Journal: :Journal of occupational and environmental hygiene 2013
Charles Beaudry Jérôme Lavoué Jean-François Sauvé Denis Bégin Mounia Senhaji Rhazi Guy Perrault Chantal Dion Michel Gérin

We created an exposure database of respirable crystalline silica levels in the construction industry from the literature. We extracted silica and dust exposure levels in publications reporting silica exposure levels or quantitative evaluations of control effectiveness published in or after 1990. The database contains 6118 records (2858 of respirable crystalline silica) extracted from 115 source...

Journal: :The Annals of occupational hygiene 2002
Farhang Akbar-Khanzadeh Randall L Brillhart

Studies reporting the findings of exposure to crystalline silica dust during concrete finishing in construction settings are scarce due to the dynamic nature of the activity and the existence of many confounding factors. This study was initiated to explore the issue. A total of 49 personal respirable dust samples were collected during concrete finishing while workers used hand-held grinders. On...

Davood Vakili Mohammad Ali Attarnejad Mohammad Mahdi Akbarnejad, Sayyed Kamal Massoodian

A new polymorph crystalline silica composition having uniform pore dimensions were synthesized by calcining a crystalline hydrated alkyl-ammonium silicate. The pore dimensions approximately were 6 angstrom for silicalite-1 and 11 angstrom for silicalite-2 units. The silicalite-1 was prepared hydrothermally at a pH of about 10 from a reaction mixture consist of water, amorphous silica and a ...

حسینی, مصطفی, رضا زاده آذری, منصو, موسوی, سجاد, پناهی, داود, کاکویی, حسین,

Introduction: Exposure to crystalline silica in the construction workers such as miners and diggers are widespread. Exposure to respirable silica (quartz) can results in silicosis. The goal of this study was to determine the contribution of each workers and component task to total dust and respirable quartz exposure in the tunnel of metro. .Method and Materials: The assessment of crystallin...

1998
Renata M. Wentzcovitch Cesar da Silva James R. Chelikowsky Nadia Binggeli

Using first principles variable cell shape molecular dynamics, we predict a new structure for silica. This structure results from annealing a-quartz at pressures near a major phonon instability. The new phase is obtained by rotations of SiO4 tetrahedra producing edge-sharing SiO6 octahedra and SiO5 cuboids. This type of mechanism was proposed to account for structural transitions in silicate me...

2010
Lance Brothers Benjamin Iverson Daniel Bour

Portland cement for high-temperature geothermal applications typically includes 35 to 40 percent crystalline quartz by weight of cement (BWOC) to avoid strength retrogression, which is defined as an increase in permeability and a decrease in compressive strength. Also, because of the reactivity of Portland cement at elevated temperatures, relatively expensive cement-hydration retarders are requ...

Journal: :Environmental Health Perspectives 1994
Y Mao L N Daniel N Whittaker U Saffiotti

The interaction of DNA with crystalline silica in buffered aqueous solutions at physiologic pH has been investigated by Fourier-transform infrared spectroscopy (FT-IR). In aqueous buffer, significant changes occur in the spectra of DNA and silica upon coincubation, suggesting that a DNA-silica complex forms as silica interacts with DNA. As compared to the spectrum of silica alone, the changes i...

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