Controlling the growth of the polymorphs of calcium carbonate is important in understanding the changing environmental conditions in the oceans. Aragonite is the main polymorph in the inner shells of marine organisms, and can be readily converted to calcite, which is the most stable polymorph of calcium carbonate. Both of these polymorphs are significantly more stable than vaterite, which is th...

Sea urchin larvae have an endoskeleton consisting of two calcitic spicules. We reconstructed various stages of the formation pathway of calcium carbonate from calcium ions in sea water to mineral deposition and integration into the forming spicules. Monitoring calcium uptake with the fluorescent dye calcein shows that calcium ions first penetrate the embryo and later are deposited intracellular...

This study aims to investigate the effects of the strength improvement of soft ground (sand) by producing calcium carbonate powder through microbial reactions. To analyze the cementation effect of calcium carbonate produced through microbial reaction for different weight ratios, four different types of specimens (untreated, calcium carbonate, cement, and calcium carbonate + cement) with differe...

The transition from invertebrate calcium carbonate-based calcite and aragonite exo- and endoskeletons to the calcium phosphate-based vertebrate backbones and jaws composed of microscopic hydroxyapatite crystals is one of the great revolutions in the evolution of terrestrial organisms. To identify potential factors that might have played a role in such a transition, three key domains of the vert...

Calcium is an essential nutrient required in substantial amounts, but many diets are deficient in calcium making supplementation necessary or desirable. The objective of this study was to compare the oral bioavailability of calcium from calcium formate, a new experimental dietary calcium supplement, to that of calcium citrate and calcium carbonate. In a four-way crossover study, either a placeb...

OBJECTIVES The tolerability and efficacy of lanthanum carbonate has not been studied in the Indian population. This study was, therefore, undertaken to compare the efficacy and tolerability of lanthanum carbonate with calcium acetate in patients with stage 4 chronic kidney disease. DESIGN A randomized open label two group cross-over study. MATERIALS AND METHODS Following Institutional Ethic...

this study was conducted to characterize the reactivity of carbonates in the surface horizons of 20 soils (entisols and aridisols) from central region of iran. the samples were analyzed for calcium carbonate equivalent (cce), active calcium carbonate equivalent (acce), non-active calcium carbonate equivalent (n.acce), carbonate mineralogy and surface area of carbonates (ssa) through n2 adsorpti...

Calcium carbonate is an important component in exoskeletons of many organisms. The synthesis of calcium carbonate was performed by mixing dimethyl carbonate and an aqueous solution of calcium chloride dihydrate. The precipitation product was characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrar...

BACKGROUND Hyperphosphatemia is common in end-stage renal disease patients. Objective of this study is to compare the hypercalcaemic effect and phosphate binding power of calcium acetate and calcium carbonate in end-stage renal disease patients on maintenance haemodialysis. METHODS This randomised control trial was conducted in four phases with calcium acetate or calcium carbonate. Sixty-four...

Calcium carbonate is an abundant substance that can be created in several mineral forms by the reaction of dissolved carbon dioxide in water with calcium ions. Through biomineralization, organisms can harness and control this process to form various functional materials that can act as anything from shells through to lenses. The early stages of calcium carbonate formation have recently attracte...