Apatites hydroxy

Hydroxy-apatite chromatography was carried out on a 1.7 ml HA-Ultrogel (IBF) column equilibrated in 10 mM phosphate buffer (pH 6). Elution was performed with a linear 10-300 mM phosphate buffer (pH 6) gradient. 

Hydroxy apatite (tricalcium phosphate) (tech grade) Dodecylbenzene sulfonate (tech grade)... 

Calcium Phosphates And Calcified Tissues. Precipitation in the system Ca(0H)2 - H3PO4 - H2O can lead to the formation of several calcium phosphates (shown in Table IV), of which hydroxy-apatite 0HA is the most stable above a pH of about 4.1. The relative stabilities are illustrated in Figure 12. 

The hydrolysis of Cap2 in solutions containing phosphates and carbonate ions results in the formation of fluor-, fluor-hydroxy- or fluor-carbonate-apatites. Fluor and fluor-hydroxy- apatites can also be formed by the hydrolysis of dicalcium phosphate (anhydrous or dihydrate), DCPAor DCPD, respectively, in solutions containing fluoride ions [121] or from the hydrolysis of any other calcium phosphate salt. 

G. Penel, G. Leroy, C. Rey, B. Sombret, J.P. Huvenne, E. Bres, Infrared and Raman microspectrometry study of fluor- fluor-hydrox- and hydroxy-apatite powders, J. Mater. Sci. Mater. Med. 8 (1997) 271-276. 

Bertolucci, Jantzef, and Chamberlain (8) report briefly on their work using single-reflection, attenuated, total-reflection, infrared spectroscopy to study the mechanism of adsorption on hydroxy-apatite crystals of citric acid, tartaric acid, sodium citrate, oxytetracycline hydrochloride, and glycine. This work has been of interest to many chemists, but it also has particular pertinency to current research on dental adhesives and the effect of pretreatment of the tooth cavity wall. 

Calcium hydroxy apatite contains the phosphate and hydroxyl groups. Using calcinm hydroxide as the precipitant, the chemical reaction is ... 

Again, as in previous chapters, the best place to investigate for determining the modes of removal is the table of solubility products constants as shown in Table 14.1. A precipitation product that has the lowest K p means that the substance is the most insoluble. As shown in the table, the phosphate ion can be precipitated using a calcium precipitant producing either Ca5(P04)3(0H)(j) or Ca3(P04)2. Of these two precipitates, Ca5(P04)3(0H)(j) has the smaller K p of 10" thus, it will be used as the criterion for the precipitation of phosphates. Ca5(P03)3(OH)(j) is also called calcium hydroxy apatite. 

Solubility product constant of calcium hydroxy apatite phosphate... 

Phosphorus occurs in nature mainly as the minerals apatite, Ca5(P04)3F, hydroxy-apatite, Ca,r,(P04)3(0H), and tricalcium phosphate (phosphate rock, ranging in composition from Ca3(P04)o to hydroxyapatite). Kydroxy-apatite is the main mineral constituent of the bones and teeth of animals, and complex organic compounds of phosphorus are essential constituents of nerve and brain tissue and of many proteins, and are involved significantly in the metabolic reactions of living organisms. 

Phosphates are valuable fertilizers. Phosphate rock itself (tricalcium phosphate, Cag(P04)o, and hydroxy-apatite) is too slightly soluble to serve as an effective source of phosphorus for plants. It is accordingly converted into the more soluble substance calcium dihydrogen phos phate, Ca(HoP04)o. This may be done by treatment with sulfuric add ... 

Ores of phosphorus apatite, hydroxy-apatite, iricalcium phosphate (phosphate rock). White phosphorus, red phosphorus, black phosphorus. High polymers and their properties. Manufacture and uses of phosphorus. Ordinary matches, safety matches. 

Sikinami, Y., and Okuno, M., Bioresorbable devices made of forged composites of hydroxy apatite particles and poly-L-lactide (PLEA) parti, basic characteristics. Biomaterials, 20, 859, 1999. 

As in the case of calcite, the activities of various dissolved species have been calculated at different pH values for other minerals using the relevant chemical equilibria and stoichiometric restrictions. The distribution of the activities of dissolved species of hydroxy apatite is given in Figs. 3.5a and 3.5b for open and closed systems, respectively. If the system is brought to equilibrium with atmospheric carbon dioxide, the distribution will follow that shown in Fig. 3.5a. For the closed system, Ca species are the most predominant... 

Research on the benthic phosphoms cycle and phosphorites formation in particular was intensified especially in the seventies to early nineties of the last century (e g. Burnet 1977 Burnett and Froelich 1988 Burnett and Riggs 1990 Nolton and Jarvis 1990 Follmi 1996 Gleim et al. 2000). All present result clearly substantiate that the process of phosphogenesis (= the authigenic formation of carbonate fluorapatite - CFA) is highly complex and not completely understood. However, hydroxy-apatite may be the primary authigenic P-... 

Zanetti D, Nassif N, Antonelli AR (2001) Surgical repair of bone defects of the ear eanal wall with flexible hydroxylapatite sheets A pilot study. OtolNeurotol 22 745-753 Zaremba CM, Morse DE, Maim S, Hansma PK, Stucky GD (1998) Aragonite-hydroxylapatite conversion in gastropod (abalone) naere. Chem Mater 10 3813-3824 Zerahn B, Kofoed H, Borgwardt A (2000) Increased bone mineral density adjacent to hydroxy-apatite-eoated ankle arthroplasty. Foot Ankle Inti 21 285-289 Zhang Y, Fu T, Xu K, An H (2001) Wet synthesis and eharacterization of fluoride-substituted hydroxylapatite. J Biomed Eng 18 173-176... 

Ternary Compounds REiMi(Si0i) 02. In order to follow the correlation between cation substitution and variation of cell dimensions in 2 8 mixed-cation apatites, we bring forward crystal data for 4 8 hydroxy apatites from 44). It is especially atractive to introduce the 4 6 apatite compounds into the discussion of crystal chemistry because their mixed-cation ratio exactly corresponds to the ratio of the symmetry-... 

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