Nanocrystalline biological apatites constitute the mineral phase of vertebrate bone and teeth. Beyond their central importance to the mechanical function of our skeleton, their extraordinarily large surface acts as the most important ion exchanger for essential and toxic ions in our body. However, the nanoscale structural and chemical complexity of apatite-based mineralized tissues is a formida...

In situ amendments are a promising approach to enhance removal of metal contaminants from diverse environments including soil, groundwater and sediments. Apatite and chitin were selected and tested for copper, chromium, and zinc metal removal in marine sediment samples. Microbiological, molecular biological and chemical analyses were applied to investigate the role of these amendments in metal ...

Forsterite ceramic is a new bioceramic with good biocompatibility. However, the degradation rate of forsterite ceramic is extremely low, and the apatite-formation ability is also poor. On the other hand, nanostructured bioceramics are expected to have better bioactivity than coarser crystals. The aim of this work was preparation, characterization and bioactivity evaluation of forsterite nanopow...

Tens of millions of people in Southeast Asia drink groundwater contaminated with naturally occurring arsenic. How arsenic is released from the sediment into the water remains poorly understood. Here, we show in laboratory experiments that phosphate-limited cells of Burkholderia fungorum mobilize ancillary arsenic from apatite. We hypothesize that arsenic mobilization is a by-product of mineral ...

Highly crystalline feedstock hydroxyapatite (HA) particles with irregular shapes were spheroidized by plasma spraying them onto the surface of ice blocks or into water. The spherical Ca-P particles thus produced contained various amounts of the amorphous phase which were controlled by the stand-off distance between the spray nozzle and the surface of ice blocks or waiter. The smooth surface mor...

Zircon and apatite crystals from the western Canadian shield yield (U-Th)/He dates that are the oldest yet reported for terrestrial rocks. Zircon dates from 1.73 to 1.58 Ga are consistent with independent geological and thermochronological constraints, and indicate that the rocks were at temperatures 180 C and crustal depths 7–10 km since ca. 1.7 Ga. Apatite dates from 0.95 to 0.55 Ga suggest r...

The present study investigates the changes in microstructure and microchemistry (particularly Ca/P ratio) during whisker formation on the surface of a monolithic TTCP powder in a basic phosphoric acid solution. The XRD results indicate that when TTCP powder was treated for 10min or less in (NH4)2HPO4 solution, the monolithic TTCP phase remains unchanged. When treated for 30min, apatite whiskers...

The purpose of this study was to examine the ul trastructural relationships of cholesterol crystals and apatite deposits in human atherosclerotic lesions. Segments of human aortic atherosclerotic lesions were obtained at autopsy , fixed in gl utaraldehyde and dehydrated without using any organic solvents. The aortic segments were coated with carbon and subjected to various scan ning electron mi...

Stable isotope analysis of skeletal tissues is widely used in archeology and paleoanthropology to reconstruct diet. In material that is poorly preserved or very old, the tissue of choice is frequently tooth enamel, since this is less susceptible to diagenesis. The relationships between carbon isotope ratios in tooth enamel (δ(13) C(enamel) ), bone collagen (δ(13) C(collagen) ), and bone apatite...

For the past 40 years, the Moon has been described as nearly devoid of indigenous water; however, evidence for water both on the lunar surface and within the lunar interior have recently emerged, calling into question this long-standing lunar dogma. In the present study, hydroxyl (as well as fluoride and chloride) was analyzed by secondary ion mass spectrometry in apatite [Ca(5)(PO(4))(3)(F,Cl,...