Evidence that crystalline silica is associated with an increased rate of lung cancer led the International Agency for Research on Cancer to conclude in 1997 that crystalline silica is a known human carcinogen. In Israel too, crystalline silica is considered as such. The decision raised a debate in the scientific arena, and a few scientists have questioned the basis upon which causality was dete...

Sol–gel synthesis of powders consisting of regularly shaped submicron silica spheres (∅400–600 nm) is described. IR and absorption spectra of such powders have been obtained. The IR spectra demonstrate that the silica spheres heated at 800 °C are hydroxyl-free. The TEM measurements show that the dimensions of silica nanoparticles do not change during heating. Films of self-organized silica nano...

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...

Novel zidovudine derivatives, able to be covalently conjugated to silica surface, have been obtained and grafted to SBA-15 mesoporous silica. Cytotoxic activity of the hybrid organic-inorganic (zidovudine derivatives-silica) systems against HeLa and KB cell lines has been analyzed. Addition of folic acid had a positive influence on the cytotoxicity. Up to 69% of HeLa and 65% of KB tumor cells g...

background: foundry workers are occupationally exposed to hazardous substances such as silica dusts and toxic gases. the aim of this study was to examine the effects of simultaneous exposure to complex mixtures of silica dust, formaldehyde, and triethylamine on lung function parameters. study design: a cross-sectional study. methods: this study was conducted on 55 male workers of core making un...

We demonstrate a sub-micron silica diaphragm-based fiber-tip Fabry-Perot interferometer for pressure sensing applications. The thinnest silica diaphragm, with a thickness of ∼320  nm, has been achieved by use of an improved electrical arc discharge technique. Such a sub-micron silica diaphragm breaks the sensitivity limitation imposed by traditional all-silica Fabry-Perot interferometric pressu...

In this paper the delivery of high power Er:YAG laser pulses through a silica hollow core photonic crystal fibre is demonstrated. The Er:YAG wavelength of 2.94 µm is well beyond the normal transmittance of bulk silica but the unique hollow core guidance allows silica to guide in this regime. We have demonstrated for the first time the ability to deliver high energy pulses through an all-silica ...

The effect of prC'adsorbed sx>lethylene oxide ( PEO) on silica on the subsequent adsorptioo of sodium dodec)1 sulfate (50s) on the silica was investipted in this study. Even though SDS does not normally adsorb on the similarly charged silica, it is shown that anionic 50s can be made to adsorb on it in the presence of preadsorbed PEO. The role of polymer molecular weight and the mode of addition...

This work first reports the preparation of super-amphiphilic silica-nanogel composites to reduce the contact angle of water to increase the diffusion of pollutant into adsorbents. In this respect, the silica nanoparticles were encapsulated into nanogels based on ionic and nonionic polyacrylamides by dispersion polymerization technique. The morphologies and the dispersion stability of nanogel co...