Dissolution mechanism of calcium apatites in acids: A review …
However, when compared with the bulk of solid apatite (Ca/P = 1.67) this layer appears to be calcium-rich (Ca/P > 1.67) when the counter anions A n-(it is assumed, that apatite is dissolved in acid H n A, where A n-is an anion) adsorbed from the solution are not taken into account. If the counter anions are calculated, a numeric value for Ca/(P ...
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Physico-chemical characterization of calcium-apatite …
Calcium phosphate materials synthesized from apatite with atomic Ca/P ratios ranging from 1.50 to 1.67 (Ca10-x(HPO4)x(PO4)6-x(OH)2-x (0 ≤ x ≤ 1)) have very interesting applications in bone regeneration and in the environment field for the removal of toxic species. The physicochemical characteristics of synthetic calcium apatite change when the Ca/P ratio …
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Apatite | Phosphate, Calcium & Fluoride | Britannica
Apatite, any member of a series of phosphate minerals, the world's major source of phosphorus, found as variously coloured glassy crystals, masses, or nodules. If not for its softness (Mohs hardness 5, compared with the 7 to 9 of most gems), apatite would be a …
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Bone Tissue Regeneration by Collagen Scaffolds with Different Calcium
It is known that ACP transforms into apatite under a normal physiological environment, because body fluid (SBF as well) is supersaturated with respect to ACP, apatite, and several other calcium phosphate phases, among which apatite is the most stable and insoluble phase .
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Bone mineral: new insights into its chemical composition
Bone is a natural composite material whose main components are mineral and organic matrices 1,2.The mature mineral matrix is in the form of nanosized, elongated platelet-like carbonated calcium ...
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Introduction to Apatites
Apatite is the generic name, which was first introduced by German geologist A.G. Werner. These minerals and their synthetic analogs represent a major class of ionic compounds and the most common crystalline …
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Calcium Phosphate
Calcium phosphate, for example, hydroxyl apatite, is a product directly comparable to rock phosphate. Thereby, one has to keep in mind that in practice the kinetics of calcium phosphate precipitation plays a major role than thermodynamic equilibrium considerations. Thus, in most cases, spontaneous precipitation of calcium phosphate from the ...
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Phosphate de calcium — Wikipédia
Leurs formules sont : phosphate tricalcique : Ca 3 (PO 4) 2 ;; l'apatite : Ca 5 (Mg,Fe 2+)(PO 4) 3 (OH), plus abondant dans les os et dents ; la whitlockite : Ca 9 (Mg,Fe 2+)(PO 4) 6 (PO 3 OH).; L'enzyme catalysant sa fixation sur l'os est la phosphatase alcaline.. Le phosphate de calcium est utilisé en chirurgie dentaire et osseuse, comme biomatériau bioactif, en raison de sa …
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Hydroxyapatite benefits, dosage, and side effects
Hydroxyapatite is a calcium-phosphate mineral complex that provides bone and teeth with their structural hardness and integrity. Medically, it has been used as an implant for …
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Phase Transformations in Calcium Phosphate Crystallization
Amorphous calcium phosphate forms easily from aqueous solution, where it subsequently transforms into, e.g., HAP. There are several excellent reviews on this subject (Combes and Rey 2010; Dorozhkin 2010) and the present discussion will therefore be kept brief.Today it is clear that there are many ways to stabilize ACPs, for example, by the addition …
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Struvite stone
Ammonia produced as a waste product by the bacteria can make the urine less acidic (or more alkaline). Struvite stones form when the urine becomes more alkaline. The main chemicals in a struvite stone include struvite (magnesium ammonium phosphate) and calcium carbon-apatite. These stones can grow quickly and become quite large.
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The role of intracellular calcium phosphate in osteoblast
The role of intracellular calcium phosphate in osteoblast-mediated bone apatite formation Proc Natl Acad Sci U S A. 2012 Aug 28;109(35):14170-5. doi: 10.1073/pnas.1208916109. ... the precise role osteoblasts play in mediating bone apatite formation remains largely unknown. To better understand the relationship between intracellular …
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Kidney stones in adults: Evaluation of the patient with
The two forms of calcium phosphate include apatite (sometimes reported as carbonate apatite), which is the crystal type found in bone, or calcium hydrogen phosphate (brushite); the frequency of apatite is much greater than brushite. Calcium phosphate crystals in the urine sediment are typically dark and amorphous. ... Zilberman DE, Tsivian M ...
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Hydroxyl apatite coating via amorphous calcium phosphate
A commercial hydroxyl apatite (CHA) was plasma-sprayed for the purpose of comparison. ... 39-44 Hydroxyl apatite coating via amorphous calcium phosphate D.M. Liu*, H.M. Chou and J.D. Wu Materials Research Laboratories, Industrial Technology Research Institute, Hsinchu, Chutung 31015 (Taiwan, ROC) M.S. Tung Paffenbarger Research Center, …
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Dissolution mechanism of calcium apatites in acids: A review …
Eight dissolution models of calcium apatites (both fluorapatite and hydroxyapatite) in acids were drawn from the published literature, analyzed and discussed. Major limitations …
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Calcium phosphates for biomedical applications
La historia de los fosfatos de calcio en el campo de la medicina comienza en 1769, cuando se descubre la primera evidencia de su existencia en el tejido óseo. ... Apatite was the first calcium phosphate recognized as mineral specie. It was in 1786 when Abraham Gottlob, well-known as the father of German geology, discovered this mineral. It was ...
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Etude de la precipitation des phosphates de calcium
Request PDF | Etude de la precipitation des phosphates de calcium | Plusieurs étapes sont observées durant la précipitation de l'hydroxyapatite (Ca/P = 1.667), en particulier pendant les deux ...
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Échographie des calcifications périarticulaires
Les calcifications périarticulaires sont la conséquence de la précipitation dans les tissus mous de cristaux de phosphate de calcium basiques (PCB), principalement d'apatite carbonatée [1]. Dans la forme primitive, les dépôts périarticulaires de PCB intéressent surtout les tendons, mais aussi les bourses, les ligaments, les capsules ...
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Apatite | Phosphate, Calcium & Fluoride | Britannica
Apatite is a member of a group of structurally related minerals having compositions symbolized A 5 (BO 4) 3 X, in which A is a metal, commonly calcium or lead; B is phosphorus, vanadium, or arsenic; and X is chlorine, …
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Apatite: Its uses as a mineral and gemstone
Apatite is the mineral used for the hardness of 5 in the Mohs Scale. It is popular as a gemstone. Its most important uses are in the production of fertilizer and phosphoric acid for the chemical industry.
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The role of intracellular calcium phosphate in osteoblast
To investigate the relationship between intracellular calcium phosphate accumulations and extracellular bone apatite formation, we cultured mouse calvarial osteoblasts and marrow stromal cells (MSC) in osteogenic medium according to standard in vitro methods for bone-like nodule formation ().We have previously demonstrated by multivariate analyses of micro-Raman …
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Nano-imaging confirms improved apatite precipitation for high phosphate
Iijima, M. & Onuma, K. Roles of fluoride on octacalcium phosphate and apatite formation on amorphous calcium phosphate substrate. Cryst. Growth Des. 18, 2279–2288.
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Alpha-TCP improves the apatite-formation ability of calcium …
The in vitro apatite-forming ability of experimental calcium-silicate hydraulic cements designed for dentistry was investigated.. Two cements containing di- and tricalcium-silicate (wTC and wTC-TCP, i.e. wTC added with alpha-TCP) were soaked in different phosphate-containing solutions, namely Dulbecco's Phosphate Buffered Saline (DPBS) or …
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Apatite Formation: Why It May Not Work as Planned, and …
This review considers the fundamentals of calcium phosphate apatite characterization discussing several techniques: electron microscopy/EDX, XRD, FTIR/Raman …
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5-1 Les phosphates de calcium
Cela i pli ue u ils so t sursaturés par rapport aux phosphates de calcium dont le produit de solubilité est i f ieu à elui de l OCP o e l h d o apatite ; ces phases ne peuvent donc pas se dissoudre (sans tenir compte du rôle des autres acteurs in vivo comme celui des cellules qui peuvent contribuer à la dégradation des CaP). Néanmoins ...
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CHAPTER 1: Biological Apatites in Bone and Teeth
Calcium phosphate nanocrystals in bone, formed as mentioned at the spaces left between the collagen fibers exhibit the particular feature of being monodispersed and nanometer-sized platelets of carbonate-hydroxyl …
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Inorganic phosphate in growing calcium carbonate abalone …
The presence of phosphate from different origins (inorganic, bioorganic) is found more and more in calcium carbonate-based biominerals. Phosphate is often described as being responsible for the ...
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Apatite | Properties, Occurrence, Uses
Apatite is a mineral with a relatively complex chemical composition, which can vary depending on the specific type of apatite. The basic formula for apatite is Ca5(PO4)3X, where X can be any one of several ions, including OH-, F-, Cl-, or a combination of these. Some variations in the formula can …
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Basics of hydroxyapatite—structure, synthesis, properties, …
Biological apatite varies in composition (it contains additional ions that play a key biological role in the development and mineralization of bone) and crystallinity. Synthetic HA can be synthesized using a range of synthesis methods that include wet-chemical and solid-state methods. ... Calcium phosphate (including HA) coatings have been ...
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Minéralisations biologiques à base de phosphate de calcium
Biological mineralisations based on calcium phosphate. The mineral fractions of bones and teeth are non-stoichiometric apatite crystals. Their morphology, dimensions, composition and reactivity ...
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