Initial Rietveld characterisation of biological calcifications

Abstract

X-ray diffraction data has been collected from biological calcific mineral associated with human bone, breast tissue, ureteric calculi, heart valve, and aorta. All the materials are shown to have a nominal calcium hydroxyapatite structure and Rietveld analysis has been performed to extract microstructural information. All refinements achieved a final Rwp value of <10%. The lattice parameter ranges are a=9.375(3)(breast)−9.4316(8)(heartvalve), c=6.866(1)(uretericcalculi) −6.899(1)(rib), and crystallite size range from 40 Å (breast) to 99 Å (ureteric calculi). A correlation between crystallite size estimates from this Rietveld analysis and line profile methods is demonstrated. The results are supported by an infrared study and previous data from alternative techniques. Thus, it is demonstrated that the microstructure of these materials may be characterised by application of the Rietveld method.

Fosfatos primários e secundários nos perfis de intemperismo sobre os Maciços Alcalino-Carbonatíticos de Juquiá (SP), Anitápolis (SC) e Tapira (MG)

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