Low-latitude continental shelves, mixed siliciclastic–carbonate sedimentary systems, provide an understanding of sedimentary environments driven by paleoclimatological processes. The Bonaparte Gulf, northwestern Australian continental shelf, is among the widest in the world, ranging to 500 km, with shallow carbonate terraces and platforms that were exposed during periods of lower sea level. The...

Contrary to common expectations, the hydroxyl scavengers, carbonate and bicarbonate, are able to enhance the phototransformation by nitrate of a number of substituted phenols. Carbonate and bicarbonate, in addition to modifying the solution pH, are also able to induce a considerable formation of the carbonate radicals upon nitrate photolysis. The higher availability of less-reactive species tha...

SMMSS, K. Calcium and carbonate metabolism in the frcg (Rana temporia) during respiratory acidosis. Am. J. Physiol. 2 14(3) : 627634. 1968.-Frogs (R. temporaria) contain large deposits of calcium carbonate in the endolymphatic sacs of the inner ear. Methods are described for determining the quantities of calcium and phosphate lost from frogs made acidotic with carbon dioxide (5-200/o in oxygen)...

Inorganic carbonate in soil occurs predominantly as the sparingly soluble alkaline-earth carbonates, calcite (CaCOs) and dolomite (CaMg(CO,),). Calcite is usually the dominant form in active pedogenic environments (Doner & Lynn, 1977; Nelson, 1982). There are only a few reported occurrences of aragonite (CaCOs) and vaterite (CaCOs) in soils. Sodium carbonate and magnesium carbonate and hydroxyc...

A new diagnostic concept based on deep Raman spectroscopy is proposed permitting the non-invasive determination of the level of carbonate substitution in type II calcifications (HAP). The carbonate substitution has shown to be directly associated with the pathology of the surrounding breast tissue and different pathology groups can therefore be separated using specific features in the Raman spe...

BACKGROUND There are not many studies evaluating the effects of surface treatments at the molecular level. The aim of this in vitro study was to analyze the concentration of carbonate molecules in dental enamel by Raman spectroscopy after the application of in-office and home whitening agents. MATERIAL AND METHODS Sixty human teeth were randomly divided into six groups and exposed to three di...

Carbonated hydroxylapatite (C-OHAp) and carbonate apatite (CAp; x 0.5) in the composition series Ca10(PO4)6–y[(CO3)x+(3/2)y(OH)2–2x], x = 0.0–0.7, y = 0.0–0.6, have been synthesized at 2–4 GPa, and studied by FTIR spectroscopy and single-crystal X-ray diffraction. Three structural locations for the carbonate ion have been identifi ed: (1) apatite channel, oriented with two oxygen atoms close to...

Studies of the average crystal structure properties of human dental apatite as a function of age in the range of 5-87 years are reported. The crystallinity of the dental hydroxyapatite decreases with the age. The a-lattice constant that is associated with the carbonate content in carbonate apatite decreases with age in a systematic way, whereas the c-lattice constant does not change significant...