The structure-directing influence of the organic dicarboxylates malonate, succinate, glutarate and adipate as templating species on the hydrothermal formation of CaCO(3) was investigated at different temperatures (60, 80, 90, 120, 150 and 190 degrees C) and with a range of molar ratios of [Ca(2+)]/[templating species] (20, 14.3, 10, 7.7, 5, 1, 0.5 and 0.33). In the presence of the dicarboxylate...

It has been estimated that under ordinary conditions from 5 to 10 per cent of all chicks hatched are weaklings that cannot be raised successfully to maturity and for this reason are destroyed by the intelligent poultryman. The cause of this condition has been attributed, 1, to a tendency of hens which have been laying heavily during the winter to lay eggs having weak germs the subsequent spring...

Carbonate sediments may be cemented by a variety of forms of aragonite. calcite. or dolomite. The mineralogy of the cement has been regarded by most investigators as the product of the physico-chemical environment within the sediment at the time of cementation. This has been a reasonable working hypothesis until it was recently demonstrated that many different kinds of cement may occur in beach...

With the aim of elucidating the details of enhanced oil recovery by surfactant solution flooding, we have determined the detailed behaviour of model systems consisting of a packed column of calcium carbonate particles as the porous rock, n-decane as the trapped oil and aqueous solutions of the anionic surfactant sodium bis-2-ethylhexyl sulfosuccinate (AOT). The AOT concentration was varied from...

Recently we have shown that supplemental dietary calcium precipitates luminal cytolytic surfactants and thus inhibits colonic epithelial proliferation, which may decrease the risk of colon cancer. In Western diets, milk products are quantitatively the most important source of dietary calcium. However, they also contain large amounts of phosphate, which has been hypothesized to inhibit the antip...

Photosymbiotic scleractinian corals are major bioengineers in tropical coastal waters, where they build structurally complex geological features and provide substrata for a manifold of macro and microhabitats. On a local scale, ecological competition and physical parameters—natural as well as human-derived, alter species richness, biodiversity, and morphological adaptation on tropical coral ree...

concentration, which, on glacial-interglacial timescales, is involved in the regulation of atmospheric pCO2. The saturation state of the ocean with respect to calcium carbonate suggests that any dissolution of calcium carbonate takes place not in the water column but at the seafloor. On the other hand, several authors suggest that a significant part of the dissolution takes place in the upper p...

Calcium gluconate production by Aspergillus niger was investigated in shake flask, rolling shaker, air-lift reactor and stirred reactor. Growth pattern of the organism and fermentation conditions determined the yield of the product. High calcium gluconate production was achieved in air-lift reactor with pellet form of cell growth at moderate specific growth rate and biomass concentration. In an...

To improve the performance of nanostructured calcium carbonate in gene delivery, a hydrophilic polysaccharide, alginate, was added to calcium carbonate co-precipitation systems to form alginate/CaCO(3)/DNA nanoparticles. The size and ζ-potential of the nanoparticles were measured by a zetasizer. Due to the existence of alginate chains which retarded the growth of calcium carbonate based co-prec...