definition of carbonate sediments to include those containing more than SO per cent carbonate minerals, many new parameters can be studied and new and useful information can be incorporated in studies of carbonate rocks. It is obvious that, by enlarging the definition, consideration of insoluble residues and stratigraphic associations is possible. Further, the geographic range of carbonate sedi...

BACKGROUND Lanthanum carbonate and sevelamer carbonate are non-calcium-based phosphate binders used to manage hyperphosphataemia in patients with chronic kidney disease (CKD). Patients with CKD may require intravenous or oral active vitamin D. We investigated the effects of lanthanum carbonate and sevelamer carbonate on the bioavailability of oral calcitriol. METHODS This was a three-period, ...

We designed a novel multifunctional β-sheet peptide template for calcium carbonate mineralization. The template self-supplies the mineral source, a carbonate ion, by hydrolysis of urea, and regulates the crystal phase and morphology of the obtained calcium carbonate.

The crystal chemistry of carbonate in Ca apatites, including Na-free and Na-bearing hydroxylapatite (CHAP) and Na-bearing fluorapatite (CFAP) and chlorapatite (CCLAP), has been investigated by Fourier transform infrared (FTIR) spectroscopy and single-crystal X-ray structure, using crystals synthesised from carbonate-rich melts at 1 GPa, 1400 1000°C. The carbonate ion substitutes for both the X ...

Though previous studies demonstrate the utility of nitrogen and carbon stable isotope ratios (?15N ?13C, respectively) in bivalve soft tissues as biogeochemical proxies, it is necessary to develop alternative proxies for environmental reconstructions when are unavailable, such with fossils or museum-archived specimens. This study assesses reliability ?15N values carbonate-bound organic matrix (...

A single-extraction procedure using low-molecular-weight organic acids (LMWOAs) as extractant and the first and second steps of a three-step extraction procedure recommended by the European Community Bureau of Reference (BCR; now European Community Standards, Measurement and Testing Programme, Brussels, Belgium) were performed to extract the light rare earth elements (LREEs) La, Ce, Pr, and Nd ...

A novel di-iron(III) catalyst for the copolymerisation of cyclohexene oxide and CO(2) to yield poly(cyclohexene carbonate), under mild conditions, is reported. The catalyst selectivity was completely changed on addition of an ammonium co-catalyst to yield only the cis-isomer of the cyclic carbonate, also under mild conditions. Additionally, the catalyst was active for propylene carbonate and st...

Computer modelling techniques have been employed to qualitatively and quantitatively investigate the uptake and distribution of carbonate groups in the hydroxyapatite lattice. Two substitutional defects are considered: the type-A defect, where the carbonate group is located in the hydroxy channel, and the type-B defect, where the carbonate group is located at the position of a phosphate group. ...