This study is focused on synthesis of nano-colloidal silica via alkaline water glass solution. Sodium ions of water glass were removed by cation exchanging in a resin column to obtain the silicic acid which was titrated to the solution of sodium silicate. Concentration of the colloidal silica and pH value of the solutions were controlled using different concentrations of alkaline sodium silicat...

The chemical affinity of silicic acid for aluminium (AI) has been shown to reduce the bioavailability of AI in studies of human gastrointestinal (GI) absorption. Investigations were carried out to ascertain whether or not similar interactions may also enhance the renal excretion of AI by assessing the urinary output of both elements. Healthy individuals given monosilicic acid as naturally found...

[1] Among phytoplankton the diatoms are strong competitors and contribute significantly to total global primary production. Aspects of their life history, notably their high sinking rates, make them important to the export flux of carbon into the ocean interior. Unlike the majority of other phytoplankton, they utilize silicic acid (=silicate) to construct their cell walls and are controlled by ...

[1] Using a simple box model, we investigate the effects of a reduced Si:N uptake ratio by Antarctic phytoplankton on the marine silica cycle and atmospheric pCO2. Recent incubation experiments demonstrate such a phenomenon in diatoms when iron is added [Hutchins and Bruland, 1998; Takeda, 1998; Franck et al., 2000]. The Southern Ocean may have supported diatoms with reduced Si:N uptake ratios ...

s i l i c i c acid column chromatography has proved very useful in the separation and isolation of many of the sterols found in the nonsaponifiable fraction of lipid mixtures (1-8). In the course of an investigation of the nonsaponifiable lipids formed from mevalonic acid-C14 by a rat ascites tumor, a highly radioactive fraction was isolated by chromatography 011 silicic acid. This fraction was...

In Demospongiae (phylum Porifera) the formation of the siliceous skeleton, composed of spicules, is an energetically expensive reaction. The present study demonstrates that primmorphs from the demosponge Suberites domuncula express the gene for arginine kinase after exposure to exogenous silicic acid. The deduced sponge arginine kinase sequence displays the two characteristic domains of the ATP...

The polycondensation kinetics of silicic acid was measured cryoscopically in a temperature interval between 5 ◦C and 35 ◦C. Unlike polyamines such as polyallylamine, polylysine or polyarginine, catalitical amounts of Cytochrom c have a distinct retarding influence on the polycondensation kinetics. The Arrhenius analysis of the experimental reaction rates with and without Cytochrome c determines...