Removal of carbon through the precipitation and burial of calcium carbonate in marine sediments constitutes over 70% of the total carbon on Earth and is partitioned between coastal and pelagic zones. The precipitation of authigenic calcium carbonate in seawater, however, has been hotly debated because despite being in a supersaturated state, there is an absence of persistent precipitation. One ...

Larger symbiont-bearing foraminifera are prominent and important producers of calcium carbonate in modern tropical environments. With an estimated production of at least 130 million tons of CaCO(3) per year, they contribute almost 5% of the annual present-day carbonate production in the world's reef and shelf areas (0-200 m) and approximately 2.5% of the CaCO(3) of all oceans. Together with non...

Hyperphosphatemia has an important role in the development of secondary hyperparathyroidism and bone disease in patients with end-stage renal disease (ESRD). The most effective method of phosphate elimination lies with phosphate binders, the agent that more commonly used, calcium carbonate, is not an ideal binding agent. In this regard, calcium acetate has been reported to have more or at least...

The efficacy of using calcium carbonate as an osmolar control treatment for acid-base studies in horses receiving alkalizing compounds was evaluated. Six mares were nasogastrically intubated with isomolar quantities of sodium or calcium as sodium bicarbonate or calcium carbonate or with water during three treatment periods. Doses of the carbonic acid salts were 500 mg/kg sodium bicarbonate mixe...

We conducted a case-control study to determine the contribution of lead to blood from consumption of calcium supplements approximating the recommended daily intakes over a 6-month period. Subjects were males and females ages 21 to 47 years (geometric mean 32 years) with a geometric mean blood lead concentration of 2.5 microg/dL. They were subdivided into three groups. One treatment group (n = 8...

in the present work, high temperature tensile properties of medium density polyethylene (mdpe) and its nanocomposites are investigated. for this purpose mdpe reinforced with different weight percentages of nano-sized calcium (2, 5, 10) are produced by compression moulding method. tensile tests have been carried out at different temperatures, i.e. 30, 60, 90c using thermomechanical analysis (tm...

Using cryogenic helium buffer-gas cooling, we have prepared dense samples of atomic lithium and molecular calcium monohydride at temperatures as low as 1 K. We have measured the Li+CaH→LiH+Ca chemical reaction, observed in both the accelerated disappearance of CaH in the presence of high densities of lithium and in the appearance of the LiH molecule.

The review focuses on the effects of several important additives and templates controlling the calcium carbonate crystals formation and the complexity of the crystal morphologies in vitro. Additives include soluble matrices extracted from shells and pearls, amino-acids, magnesium ions and collagen among others. Templates include modified single crystal silicon, natural biominerals among others....

The effect of amphoteric siderophore deferoxamine on the crystallization behavior of calcium carbonate was investigated under bioinspired conditions. Amphoteric siderophore deferoxamine possesses selforganization ability, surface activity and ion-chelating properties. It induces in the present case the formation of unusual, highly organized aragonite mesocrystals during the precipitation of cal...

Scale and corrosion control are big challenges in utilizing geothermal energy. In the production wells, during or after flashing, brineresults in higher pH, which can happen deep inside the well.Higher pH in combination with high temperature causes calcium carbonate precipitation. Silica/Silicate precipitation becomes a problem when the brine gets cold in the surface equipment and the rejection...