The impact of immobilization of oxazaborolidines supported on silica via different substituents on the boron and nitrogen atoms is evaluated in the enantioselective reduction of acetophenone. The performances of the homogeneous analog oxazaborolidines and silica supported-ones are compared by varying different parameters. This article deals with the synthesis, characterization and catalytic eva...

This paper reports a systematic investigation of the growth and attachment of small gold nanoparticles to the functionalized surfaces of larger silica nanoparticles. Dilution of the gold nanoparticles in mixtures of water and ethanol led to the self-assembly of gold nanoparticles in aggregates of regular size and shape attached to the surfaces of the silica nanoparticles. Functionalization of t...

PURPOSE Both polymer micelles and mesoporous silica nanoparticles have been widely researched as vectors for small molecular insoluble drugs. To combine the advantages of copolymers and silica, studies on the preparation of copolymer-silica composites and cellular evaluation were carried out. METHODS First, a stearic acid-g-chitosan (CS-SA) copolymer was synthesized through a coupling reactio...

Silica-natural rubber nanocomposites were obtained through a novel non-aqueous in situ sol-gel synthesis, producing the amount of water necessary to induce the hydrolysis and condensation of a tetraethoxysilane precursor by esterification of formic acid with ethanol. The method allows the synthesis of low hydrophilic silica nanoparticles with ethoxy groups linked to the silica surface which ena...

An experimental study was performed to understand the ability of highly charged nanoparticles to stabilize a dispersion of weakly charged microspheres. The experiments involved adding either anionic (sulfate) or cationic (amidine) latex nanoparticles to dispersions of micrometer-sized silica particles near the silica isoelectric point (IEP). Although both types of nanoparticles increased the ze...

Silica nanoparticles have become promising carriers for drug delivery or gene therapy. Endothelial cells could be directly exposed to silica nanoparticles by intravenous administration. However, the underlying toxic effect mechanisms of silica nanoparticles on endothelial cells are still poorly understood. In order to clarify the cytotoxicity of endothelial cells induced by silica nanoparticles...

Cyanide-functionalized mesoporous silica SBA-15 (CN/SBA-15) with pore diameters larger than 6 nm has been prepared by a one-pot synthesis. The structure of CN/SBA-15 is affected by the amount of the functional silane 2-cyanoethyltriethoxysilane (CTES) and the conditions of co-condensation in the acidic aqueous solution of the triblock copolymer Pluronic P123: whereas direct mixing of the silica...

OBJECTIVES To assess the bonding potential of a universal composite resin cement and an adhesive/composite system to differently pre-treated PEEK surfaces. METHODS One hundred and fifty PEEK disks were embedded in epoxy resin, polished (P4000 grit) and treated as follows (n=30/group): (A) no treatment, (B) acid etching with sulfuric acid (98%) for 1 min, (C) sandblasting for 10s with 50 micro...

Via the one-pot condensation reaction of ethyl acetoacetate, aromatic aldehydes, 2,4-dinitrophenylhydrazine, and β-naphthol; new pyrazolone derivatives were synthesized in the presence of three Brønsted acid catalysts. These Brønsted acid catalysts are Silica sulfuric acid (SSA), tetra-n-butyl ammonium hydrogen sulfate (TBAHSO4) and [2,2′-Bipyridine]-1,1′-diium tricyanomethanide {[2,2′-BPyH][C(...