Search results for "apatite"

Premature aging in bone of fish from a highly polluted marine area

2015

Fish species have attracted considerable interest in studies assessing biological responses to environmental contaminants. In this study, the attention has been focussed on fishbone of selected fish species from a highly polluted marine area, Augusta Bay (Italy, Central Mediterranean) to evaluate if toxicant elements had an effect on the mineralogical structure of bones, although macroscopic deformations were not evident. In particular, an attempt was made to evaluate if bone mineral features, such as crystallinity, mineral maturity and carbonate/phosphate mineral content, determined by XR-Diffraction and FT-IR Spectroscopy, suffered negative effects due to trace element levels in fishbone,…

Coating su substrati metallici per applicazioni in campo ortopedico

2022

Co-deposition and characterization of hydroxyapatite-chitosan and hydroxyapatite-polyvinylacetate coatings on 304 SS for biomedical devices

2019

During the last decades, biomaterials have been deeply studied to fabricate and improve coatings for biomedical devices. Metallic materials, especially in the orthopedic field, represent the most common materials used for different type of devices thanks to their good mechanical properties. Nevertheless, low/medium resistance to corrosion and low osteointegration ability characterizes these materials. To overcome these problems, the use of biocoatings on metals substrate is largely diffused. In fact, biocoatings have a key role to confer biocompatibility features, to inhibit corrosion and thus improve the lifetime of implanted devices. In this work, the attention was focused on Hydroxyapati…

Composite Scaffolds with a Hydrohyapatite Spatial Gradient for Osteochondral Defect Repair

2018

Osteochondral defects derived by traumatic injury or aging related disease are often associated with severe joint pain and progressive loss of joint functions for millions of people worldwide and represent a major challenge for the orthopedic community. Tissue engineering offers new therapeutic approach to repair the osteochondral defects, through the production of scaffolds manufactured to mimic their complex architecture, which consists of cartilage and bone layers. Composite scaffolds based on a PLLA polymeric matrix containing hydroxyapatite (HA) as a filler were prepared through a modified thermally induced phase separation (TIPS) protocol. A suspension was prepared by adding sieved HA…

The volatile inventory (F, Cl, Br, S, C) of magmatic apatite: An integrated analytical approach

2012

Abstract Apatite is ubiquitous in a wide range of magmatic rocks and its F–Cl–Br–S systematics can be used to decipher e.g., mixing processes within a magmatic complex and may give insights into fluid un-mixing and degassing processes during the emplacement and cooling of plutonic rocks. In this study, we analyzed a F-apatite (Durango, Mexico), a Cl-apatite (Odegarden, Norway) and apatites from five plutonic samples from the alkaline Mt. Saint Hilaire Complex (Canada) by means of Electron Microprobe Analysis (EPMA), Laser Ablation ICP-MS (LA-ICP-MS), Secondary Ion Mass Spectrometry (SIMS), pyrohydrolysis combined with ion chromatography, Fourier Transformed Infrared Spectroscopy (FTIR), Ins…

RF magnetron-sputtered coatings deposited from biphasic calcium phosphate targets for biomedical implant applications

2017

Bioactive calcium phosphate coatings were deposited by radio-frequency magnetron sputtering from biphasic targets of hydroxyapatite and tricalcium phosphate, sintered at different mass % ratios. According to Raman scattering and X-ray diffraction data, the deposited hydroxyapatite coatings have a disordered structure. High-temperature treatment of the coatings in air leads to a transformation of the quasi-amorphous structure into a crystalline one. A correlation has been observed between the increase in the Ca content in the coatings and a subsequent decrease in Ca in the biphasic targets after a series of deposition processes. It was proposed that the addition of tricalcium phosphate to th…

Chemical composition of modern and fossil Hippopotamid teeth and implications for paleoenvironmental reconstructions and enamel formation – Part 1: M…

2012

Bioapatite in mammalian teeth is readily preserved in continental sediments and represents a very important archive for reconstructions of environment and climate evolution. This project provides a comprehensive data base of major, minor and trace element and isotope tracers for tooth apatite using a variety of microanalytical techniques. The aim is to identify specific sedimentary environments and to improve our understanding on the interaction between internal metabolic processes during tooth formation and external nutritional control and secondary alteration effects. Here, we use the electron microprobe to determine the major and minor element contents of fossil and modern molar enamel, …

Formation of Calcium-Deficient Hydroxyapatite via Hydrolysis of Nano-Sized Pure Α-Tricalcium Phosphate

2015

Nano-sized pure α-tricalcium phosphate (α-TCP) fabricated by a novel synthesis approach shows great potential for a faster transformation into calcium-deficient hydroxyapatite (CDHA) than conventionally prepared α-TCP. In this work, amorphous tricalcium phosphate precursors were precipitated and treated with a solvent (water or ethanol), and dried (freeze-dried and oven-dried) before heating at 775 °C. Nanosized α-TCP powders were investigated for their phase composition and crystallinity, particle shape and size, reactivity and cellular biocompatibility. Reaction with water showed faster CDHA formation for freeze-dried powder, at 6 hours, compared to ethanol treated powders, whereas a high…

Apatite and clinopyroxene as tracers for metasomatic processes in nepheline clinopyroxenites of Uralian-Alaskan-type complexes in the Ural Mountains,…

2013

Clinopyroxene and apatite are found to trace metasomatic processes in nepheline-bearing clinopyroxenites (tilaites) from the igneous, mafic-ultramafic Uralian-Alaskan-type complexes of Kytlym and Nizhny Tagil, Ural Mountains, Russian Federation. The clinopyroxenites consist predominantly of coarse-grained, partially to totally altered clinopyroxene phenocrysts in a matrix of fine-grained olivine, clinopyroxene, plagioclase, K-feldspar, and nepheline. Apatite occurs as idiomorphic inclusions (2O-, Na2O-, and Al2O3-bearing fluid. During conversion of the plagioclase, CaO and SiO2 were partitioned into the fluid. Altered areas in the clinopyroxene phenocrysts are characterized by the redistrib…

Small-sized granules of biphasic bone substitutes support fast implant bed vascularization

2015

The present study investigated the influence of granule size of 2 biphasic bone substitutes (BoneCeramic® 400-700 μm and 500-1000 μm) on the induction of multinucleated giant cells (MNGCs) and implant bed vascularization in a subcutaneous implantation model in rats. Furthermore, degradation mechanisms and particle phagocytosis of both materials were examined by transmission electron microscopy (TEM). Both granule types induced tissue reactions involving primarily mononuclear cells and only small numbers of MNGCs. Higher numbers of MNGCs were detected in the group with small granules starting on day 30, while higher vascularization was observed only at day 10 in this group. TEM analysis reve…