In this work, we show that if the mere procedure of impregnation of oxide supports with chloroauric acid, which is well-known to lead to large gold particles, is followed by a step of washing with ammonia, small gold particles (3-4 nm) can be obtained after a treatment of calcination at 300 degrees C on any type of oxide supports (alumina, titania, silica). Moreover, gold leaching is very limit...

Blocks of the kidney and other organs of the guinea pig fixed with glutaraldehyde and treated with tannic acid and osmium tetroxide could, without any coating, be observed in the scanning electron microscope. Undesirable charging effect was inconspicuous when accelerating voltage 5-25kV was used. A scanning image of the renal glomerulus was shown and the details of the method were described. Th...

This paper presents a review of the literature concerning development of the stationary phases for thin-layer chromatography (TLC) in the last ten years. The silica gel remains the most important adsorbent for TLC separation. The kinetic properties of the silica-gel thin layer and the new TLC plates have been presented. Other materials used as stationary phase were alumina, zirconium oxide, Flo...

J.P. Rodriguez (1, 2, 3), V. Parthe (2), R.Vargas (2), L. Mateu (2), E. Vonasek (2), J. Rojas Varela (3), C. Cavaro-Menard (3), and F. Chapeau-Blondeau (3). (1,2,3) CEBIV-IDECYT. Universidad Simón Rodríguez, Apdo.47.925, Caracas-Venezuela. (2) Laboratorio de Estructura Molecular (LEM) Departamento de Biologia Estructural, Instituto Venezolano de Investigaciones Científicas IVIC, Apdo. 21827 Car...

A supercritical fluid can be used in substitution of the original organic solvent for the preparation of pharmaceutical forms. The steps involved in the preparation are essentially similar to those of the traditional preparation but in this case the final purification is not required. The interest in the supercritical fluid impregnation of polymeric materials stems from the opportunity to utili...

The objective of this research is to produce the low-cost activated carbon from Jatropha curcas L. by chemical activation using zinc chloride ZnCl2. The effects of the impregnation ratio on the surface and chemical properties of activated carbon were investigated. The impregnation ratio was selected at the range of 1:1-10:1 for investigation. The optimum conditions resulted in an activated carb...

bis(2-r-ind)zrcl2 (r: h or phenyl) was supported on different types of silica by in situ impregnation method and used for ethylene polymerization. in this method, the step of catalyst loading on support was eliminated and common alkyl aluminum (triisobutylaluminum, tiba) cocatalyst was used instead of expensive methyl aluminiumoxane (mao) cocatalyst in the polymerization. the effect of surface ...

BACKGROUND Neuropathy is one of the major complications contributing to morbidity in patients with diabetes mellitus. The effect of diabetes on brain has not been studied so much and no gross abnormality has been found in the central nervous system of patients with diabetic neuropathy. This study was conducted to evaluate the time-dependent structural changes in medial prefrontal cortex of male...