Single crystals of natural F-rich apatite and 800 keV Kr21 ion-beam–amorphized apatite were irradiated by an electron beam in a transmission electron microscope over a range of beam energies and beam currents. Irradiation of crystalline apatite using a high current density (16 A/cm2) caused the precipitation of cubic CaO from the crystalline apatite matrix. Using a lower beam current (1.6 A/cm2...

High-precision stepped-heating experiments were performed to better characterize helium diffusion from apatite using Durango fluorapatite as a model system. At temperatures below 265øC, helium diffusion from this apatite is a simple, thermally activated process that is independent of the cumulative fraction of helium released and also of the heating schedule used. Across a factor of -4 in grain...

Bioactive glass-containing toothpastes for treating dentine hypersensitivity work by precipitating hydroxycarbonate apatite (HCA) onto the tooth surface, but concerns exist over the long-term durability of HCA in the mouth. Fluoride-containing bioactive glasses form fluorapatite (FAp) in physiological solutions, which is more chemically stable against acid attack. The influence of phosphate con...

Bone-like apatite formed on the surface of Ti6Al4V pretreated with NaOH solution after having been immersed in simulated body fluid (SBF), while no apatite formed on the surface of untreated Ti6Al4V. In the present study, electrochemical impedance spectroscopy (EIS) measurement was used to investigate the nucleation and growth of apatite on chemically treated Ti6Al4V immersed in the SBF solutio...

Sediment amendments provide promising strategies of enhancing sequestration of heavy metals and degradation of organic contaminants. The impacts of sediment amendments for metal and organic remediation including apatite, organoclay (and apatite and organoclay in geotextile mats), acetate, and chitin on environmental microbial communities in overlying water and sediment profiles are reported her...

In this study, waste shrimp shells from industry were used as a heterogeneous bio-based catalyst for trans-esterification reaction of fresh palm oil. CaO was prepared calcination. Surface area, phase composition, and basicity the calcined shell catalysts studied using N2 adsorption (BET), X-ray diffraction (XRD), CO2 temperature-programmed-desorption (CO2-TPD), respectively. The influence calci...

The bioactive glass 45S5 was crystallized to 8-100 vol % of crystals by thermal treatments from 550-680 degrees C. The micro-structure of the glass-ceramics had a very uniform crystal size, ranging from 8 to 20 microns. Fourier-transform infrared (FTIR) spectroscopy was used to determine the rate of hydroxycarbonate apatite (HCA) formation that occurs on bioactive glass and glass-ceramic implan...

Bone morphogenetic proteins (BMPs) need an effective delivery system for efficient bone regeneration. In this study, we evaluated the efficiency of an apatite-coated collagen sponge for the long-term delivery of BMP-2 in a rabbit model of lumbar posterolateral fusion. A total of 15 rabbits, divided into three groups, underwent posterolateral lumbar fusion. The first group (control group) receiv...