Impregnation and deposition-precipitation syntheses have been used to obtain Y2O3/SiO2 samples. In the deposition method, the urea causes the precipitation of yttrium hydroxide, which leads to the formation of yttria nanocrystalline particles in the final composites. Delaying the silica addition up to the visible muddying of the solution, a relevant formation of yttria nanocrystalline particles...

We have developed an automated method for measuring high-density lipoprotein (HDL)-cholesterol in serum without prior separation, using polyethylene glycol (PEG)-modified enzymes and sulfated alpha-cyclodextrin. When cholesterol esterase and cholesterol oxidase enzymes were modified with PEG, they showed selective catalytic activities towards lipoprotein fractions, with the reactivity increasin...