Quartz freshly fractured

X-Ray irradiation of quartz or silica particles induces an electron-trap lattice defect accompanied by a parallel increase in cytotoxicity (Davies, 1968). Aluminosilicate zeolites and clays (Laszlo, 1987) have been shown by electron spin resonance (e.s.r.) studies to involve free-radical intermediates in their catalytic activity. Generation of free radicals in solids may also occur by physical scission of chemical bonds and the consequent formation of dangling bonds , as exemplified by the freshly fractured theory of silicosis (Wright, 1950 Fubini et al., 1991). The entrapment of long-lived metastable free radicals has been shown to occur in the tar of cigarette smoke (Pryor, 1987). 

Vallyathan, V., Castranova, V., Pack, D., Leonard, S., Shumaker, J., Hubbs, A. F., Shoemaker, D. A., Ramsey, D. M., Pretty, J. R., Mclaurin, J. L., Khan, A., and Teass, A. (1995) Freshly fractured quartz inhalation leads to enhanced lung injury and inflammation Potential role of free radicals Am. J. Resp. Grit. Care Med., 152, 1003-1009. 

Freshly fractured quartz-silica contains free radicals on the surface that have the ability to regulate cytokine gene expression (112,113). 

Vallyathan V, Castranova V, Pack D, et al. Freshly fractured quartz inhalation leads to enhanced lung injury and inflammation. Potential role of free radicals. Am J Respir Crit Care Med 1995 152 1003-1009. 

FIGURE 4.30. A schematic diagram illustrating stepwise water-surface interactions with freshly cleaved or fractured quartz. (Reprinted from Dove and Rimstidt. 1994 by permission of the Mineralogical Society of America.)... 

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