Bioactive PLLA/surface-grafted silica (g-SiO₂) nanocomposite scaffolds were fabricated by solid-liquid phase separation method. And solid PLLA/g-SiO₂ nanocomposite films were prepared by solution casting method. A series of parallel tube-like morphology and internal ladder-like structure of PLLA/g-SiO₂ nanocomposite scaffolds were observed by SEM. The formation of bone-like apatite in the simul...

The aims of this study were to evaluate the effects of CPP method on the crystallinity of apatite powder and on the acid resistance of bovine enamel. Crystallinity degrees of apatite powder before and after CPP treatment were measured by powder X-ray diffraction analysis. Polished bovine enamel specimens treated with CPP method or NaF were immersed in a lactic acid solution for up to five days....

-Oxygen isotope composition of three types of unique nodules which consist of amorphous silica-apatite, cristobalite-apatite and tridymite-apatite associations interspersed amidst basaltic pyroclastics from the Hat Peres volcano, Golan Heights, Israel is reported. Unusual isotopic temperature (75~ estimated from oxygen isotope fractionation between cristobalite (6'80 = +25.5%0-apatite (6'80 = +...

Liu et al. [1] explained the possible cariostatic mechanisms of the combined fluoride-laser treatment. They suggested that a laser-induced purification of the human enamel hydroxy apatite structure takes place and plays the major role in this cariostatic process. They also mentioned that the low-energy laser treatment has a photo thermal effect that may cause a reduction in enamel permeability....

Many advances have been made in radiocarbon dating of bone organics, but research on 14C dating of bone inorganic carbon has lagged significantly behind. Using mammoth bone, enamel, and tusk from the Dent and Murray Springs Clovis sites, experiments with the Haas and Banewicz technique of bone apatite dating by step heating demonstrate that accurate radiocarbon ages can be produced from bone ap...

introduction iron-apatite ore deposits well known as kiruna iron type formed in association with calc-alkaline volcanism from proterozoic to tertiary (hitzman et al., 1992). liquid immiscibility in an igneous system was proposed to explain the formation of the iron oxides accompanying apatite in mineralized zones (förster and jafarzadeh, 1994; daliran, 1999). the mode of ore formation however, ...

This article presents an investigation on the application of amino acids to control CaCO3 crystallization in carbonation cured wollastonite composites. It was observed that carbonated without any acid formed calcite as primary polymorph CaCO3. In contrast, use admixtures resulted formation stable amorphous calcium carbonate (ACC), vaterite, and aragonite during wollastonite. The composites prod...

Surface modifications of glass-reinforced hydroxyapatite composites immersed in a simulated physiological solution were studied using X-ray photoelectron spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. In the first stages of the apatite formation process, calcium and silicon ions were leached out from the surface of the composites. After 12 days of immersion...

Apatite contains only traces of uranium, yet as apatite is a minor constituent in most rocks and the major constituent of a few very large deposits, it accounts, paradoxically, for both dispersal and concentration of uranium in nature. Uranium typically makes up 0.001 to 0.01 percent of primary igneous apatite and 0.005 to 0.02 percent of sedimentary marine apatite. Marine reworked apatite beco...