Here we investigate the dynamic self-assembly pathway of ordered gold nanocrystal arrays during the self-assembly of gold nanocrystal micelles, with and without the presence of colloidal silica precursors, using grazing-incidence X-ray scattering performed at a synchrotron source. With silica precursors present, a lattice with rhombohedral symmetry is formed from the partial collapse of a face-...

Uniform hollow silica nanospheres (HSNs) synthesized with reverse microemulsion have great application potential as nanoreactors because enzymes or nanocatalysts can be easily encapsulated de novo in synthesis. Water-in-oil (w/o) reverse microemulsions comprising the polymeric surfactant polyoxyethylene (5) isooctylphenyl ether (Igepal CA-520), ammonia and water in a continuous oil phase (alkan...

background and objectives: the plants belonging to the genus heliotropium l. (boraginaceae) are the main sources of toxic pyrrolizidine alkaloids (pas). in the present study, we have investigated the pas of the aerial parts of heliotropium transoxanum bunge, a perennial species native to iran. methods: silica gel column chromatography and silica gel ptlc were applied for the isolation of pas pr...

Mesoporous silica pillared clay (SPC) incorporated with tungstophosphoric acid (HPW) has been synthesized via in situ introducing P and W source in the acidic suspension of the clay interlayer template during the formation of the silica pillared clay. The samples were characterized by XRD, XRF, FT-IR, TG-DTA, N(2) adsorption-desorption, and SEM techniques. The results showed that the HPW formed...

Silica exists in both crystalline and noncrystalline forms, with crystalline silica being the hazard of concern. Silica, or silicon dioxide, exposure is associated with many occupations, including construction workers, laborers, miners, foundry workers, glassmakers, drywall finishers, bricklayers, and tuckpointers.(1) Crystalline silica occurs most commonly in the form of quartz, cristobalite, ...