Search results for "apatite"
showing 10 items of 155 documents
In vitro corrosion and biocompatibility of brushite/hydroxyapatite coatings obtained by galvanic deposition on 316LSS
2018
Corrosion behavior and cytotoxicity was reported for mixed brushite (BS)/hydroxyapatite (HA) coatings deposited on 316LSS substrate through a displacement reaction. Corrosion tests, carried out in a simulated body fluid, showed that in comparison with bare 316L, coating shifts Ecorrto anodic values and reduces icorreven if oscillations were observed, which were explained in terms of the chemical interactions at the solid/liquid interface. Cell biocompatibility of the coating was investigated through osteoblastic cell line MC3T3-E1, evidencing the absence of any cytotoxicity Taken together, the results show that galvanic deposition is a simple and cost-effective method for producing bioactiv…
A sustainable replacement for TiO2 in photocatalyst construction materials: Hydroxyapatite-based photocatalytic additives, made from the valorisation…
2018
The use of waste materials and by-products in building materials is of increasing importance to improve sustainability in construction, as is the incorporation of photocatalytic materials to both combat atmospheric pollution and protect the structures and façades. This work reports the innovative use of photocatalytic hydroxyapatite (HAp) based powders, derived from Atlantic codfish bone wastes, as an additive to natural hydraulic lime mortars. HAp is the main component of bone, and hence is non-toxic and biocompatible. This is the first time that such a calcium phosphate-based photocatalyst, or indeed any fish/marine derived wastes, have been added to building materials. A key factor is th…
Method of Discrimination of Surface Fractality
1993
Abstract A simple method for the discrimination of surface fractality is proposed. This method is based on the comparison of the nitrogen adsorption isotherm on a given sample with the "standard" isotherm on a smooth surface. The proposed comparative method makes it possible to determine the lower limit of the scale range of surface fractality. A thermodynamic method is recommended as a complement to fractal analysis in the scale range of about 10-1000 A. The results of the investigation of surface roughness are presented with examples of typical samples of silica gels, porous glasses, apatite, and coal.
Nanocomposites of bacterial cellulose/hydroxyapatite for biomedical applications.
2008
In the present work, a nanocomposite material formed by bacterial cellulose (BC) networks and calcium-deficient hydroxyapatite (HAp) powders was synthesized and characterized. The HAp nanoparticles were previously prepared by a wet chemical precipitation method, starting from aqueous solutions of calcium nitrate and di-ammonium phosphate salts. Energy-dispersive spectroscopy reveals that the prepared HAp corresponds to calcium-deficient hydroxyapatite. BC-HAp nanocomposites were prepared by introducing carboxymethylcellulose (CMC) into the bacteria culture media. HAp nanoparticles were then introduced and remained suspended in the culture medium during the formation of cellulose nanofibrils…
Preparation, characterization and in vitro test of composites poly-lactic acid/hydroxyapatite scaffolds for bone tissue engineering.
2018
Abstract In this work, the possibility to produce composite Poly-L-lactic acid (PLLA)/Hydroxyapatite (HA) porous scaffolds via Thermally Induced Phase Separation (TIPS) for bone tissue engineering applications was investigated. Several PLLA/HA wt/wt ratios (95/5, 90/10, 70/30, 50/50, 34/66) were tested and the as-obtained scaffolds were characterized via Scanning Electron Microscopy, Wide Angle X-Ray Diffraction, Thermogravimetric analysis, Gas Pycnometry, Differential Scanning Calorimetry and mechanical compression test. Morphological analysis revealed an open structure with interconnected pores and HA particles embedded in the polymer matrix. Finally, cell cultures were carried out into t…
In vivo comparison of a granular and putty form of a sintered and a non-sintered silica-enhanced hydroxyapatite bone substitute material
2019
Improved handling characteristics of bone substitute materials may facilitate surgical handling. However, the respective modifications should not alter the biological activity. For comparison of a ...
Effect of addition of Nano hydroxyapatite particles on wear of resin modified glass ionomer by tooth brushing simulation
2016
Background Recently, incorporation of nanohydroxyapatite (NHA) has been suggested to improve the mechanical properties of glass ionomers (GIs). This study aimed to assess the effect of addition of NHA on wear of resin modified glass ionomer (RMGI) by tooth brushing simulation. Material and Methods In this in vitro, experimental study, NHA in 1, 2, 5, 7 and 10wt% concentrations was added to Fuji II LC RMGI powder, and 48 samples (5×5mm) in five experimental and one control group (n=8) were fabricated. After polishing, cleaning and incubation at 37°C for three weeks, the samples were weighed and subjected to tooth brushing simulation in a toothpaste slurry according to ISO14569-1. Then, they …
Cloning and Targeted Deletion of the Mouse Fetuin Gene
1998
We proposed that the alpha2-Heremans Schmid glycoprotein/fetuin family of serum proteins inhibits unwanted mineralization. To test this hypothesis in animals, we cloned the mouse fetuin gene and generated mice lacking fetuin. The gene consists of seven exons and six introns. The cystatin-like domains D1 and D2 of mouse fetuin are encoded by three exons each, whereas a single terminal exon encodes the carboxyl-terminal domain D3. The promoter structure is well conserved between rat and mouse fetuin genes within the regions shown to bind transcription factors in the rat system. Expression studies demonstrated that mice homozygous for the gene deletion lacked fetuin protein and that mice heter…
Histones and non-histone proteins during sea urchin development
1979
Abstract Chromatin from blastulae and plutei of Paracentrotus lividus was fractionated through a hydroxyapatite column. The ratio of histones versus non-histone proteins decreases from blastula to pluteus stage.
Home Oral Care Domiciliary Protocol for the Management of Dental Erosion in Rugby Players: A Randomized Clinical Trial
2022
People performing regular physical activity are at high risk of dental erosion especially in cases of high sport drinks intake. Biomimetic hydroxyapatite-based oral hygiene products, like toothpastes and mouthwashes, have been investigated in recent years for their remineralizing activity on the teeth. The aim of the present study was to evaluate the efficacy of two different oral hygiene protocols, respectively consisting of the combination of a hydroxyapatite-based toothpaste plus mouthwash (Trial group) or toothpaste alone (Control Group). At baseline (T0), as well as at 15 days (T1), 30 days (T2) and 90 days (T3), the following clinical indexes were assessed: Basic Erosive Wear Examinat…