Topic
Hydroxyapatites
About: Hydroxyapatites is a research topic. Over the lifetime, 424 publications have been published within this topic receiving 16301 citations.
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Book•
1 Jan 1994
TL;DR: In this paper, the authors describe the structure of carbonate apatites and the properties of apatite powders, including their properties in terms of their nucleation and crystal growth.
Abstract: 1. General Chemistry of the Calcium Orthophosphates. Introduction. Monocalcium phosphates (monohydrate and anhydrous). Octacalcium phosphate. Dicalcium phosphate dehydrate, brushite. Dicalcium phosphate anhydrous, monetite. Anhydrous tricalcium phosphates and whitlockite. Tetracalcium phosphate. Amorphous calcium phosphates. 2. Fluorapatite and chlorapatite. Introduction. Structures. Substitutions in apatites. Preparation of powders. Growth of single crystals. Infrared and Raman spectra. Other physical and chemical studies. 3. Hydroxapatite and Nonstoichiometric Apatites. Introduction. Structure of hydroxyapatite. Preparation of stoichiometric hydroxyapatite powders. Preparation of other apatites with hydroxyl ions. Growth of hydroxyapatite single crystals. Special analytical methods. Structure of calcium-deficient hydroxyapatites. Kinetics of nucleation and crystal growth. Solubility and interfacial phenomena. Reactions in solution. Infrared and Raman spectroscopy. NMR spectroscopy. Other physical and chemical studies. 4. Mineral, synthetic and biological carbonate apatites. Introduction. Francolite and dahllite. A-type carbonate apatite, Caio(PO4)6CO3. Synthetic high temperature B-type carbonate apatites. Carbonate apatites from aqueous systems. Biological apatites. Electron spin resonance of X-irradiated carbonate apatites. Summary. Appendix. Calculated X-ray diffraction patterns of the calcium orthophosphates. References. Index.
2,846 citations
TL;DR: In this paper, a review summarizes recent and very recent work on preparing substituted hydroxyapatites for a wide range of biomedical applications, including repairing and replacing diseased and damaged parts of musculoskeletal systems and also as a drug or gene delivery agent, as a bioactive coating on metallic osseous implants, biomagnetic particles and fluorescent markers.
692 citations
TL;DR: In this article, the infrared spectra of powdered strontium and barium hydroxyapatites and their deuterated analogs were reported at 48 and 185 deg in the 4000-200cm-/sup 1/ region.
Abstract: The infrared spectra of powdered calcium hydroxyapatite isotopically substituted with D, /sup 18/O, /sup 44/Ca, and /sup 48/Ca and infrared spectra of powdered strontium and barium hydroxyapatites and their deuterated analogs are reported at 48 and - 185 deg in the 4000-200cm-/sup 1/ region. Band assignments, based on isotopic frequency shifts, band intensity, band temperature dependency, and comparisons between corresponding bands of these structurally related apatites are presented for the above and other apatites. (auth)
645 citations
TL;DR: The results presented here support the idea that sublInits are active in polypeptide initiation; but at first sight they tend to contradict the conclusion that monosomcs are inactive.
Abstract: On the other hand, Hardesty et al. 10 and Lamfrom and Knopf\" have suggested that mono somes do initiate globin chains. Under the conditions used by these authors for the preparation of monosomes, sub-units would have been disaggregated. It is likely, however, that the monosomeR 'were not resolved from tho disaggregatcd sub-units. The mOllosomes used by Goodman and Rich 25 in reaching the same conclusion from tlxperiments with an ascites cell systom were marc thoroughly purified. However, it iH not known whether or not ascites cell native sub-units wonld be aggregated under the conditions of isolation. The results presented here support the idea that sublInits are active in. polypeptide initiation; but at first sight they tend to contradict the conclusion that monosomcs are inactive. Monosomes are clearly shown to be active in polyphenylalanine synthesis, although less so than sub-Ul~its. However, it is by no means certain that the properties of poly-U and the endogenolls informat.ional RNA are the same. Secondly, in the experiments Toported here the ratio of poly-U molecules to ribosomes was of the order of 100 : 1. In the endogenous situation it is likely to be less than 1 : 1. The reactivity of tho ribosome fractions with poly-V may not be a certain index of their behaviour either within the cell or ill tho cell-free system without added polynucleotide_ I thank Mrs. Norma Robertson for her assistance, and MI'. B. B. Cohen for his advice. This work was supportcd by grants from the Medical Research Council. 1 Arnstein, H. R. V., Biochem. J., 81, UP (:t (l61). , Glerer, A., J. Mol. Bioi., 6, 148 (1963). 3 Marks, P. A., Burka, E. R ., and SchleSSinger, D., Proc. U.S. Aat . Acad. S\"i., 48, 2163 (1962). • Warner, ,J. Ro, Knopf, P. }l., a.nd Rich, A. , Proc. U. S . Nal. Acad. Sci. , 49 122 (1963). '1'8'0, P. O. P., and Vinograd, J., BiocMm. Biophys. A cta, 49,113 (1961). • Wettstein, }'. 0 ., Staeheliu, T. , a.nd Noll, H., Nature, 197, 430 (1963). , Hi.llOp, J. 0., Biachim. Biopltvs. Acta (in the press). • Warner, .J. Ro, and Rich, A., J. Mol. Bioi., 10, 202 (1964). • Mat.hias, A. 1'., Williamson, R . , Huxley, R . Eo, auu Page , S., .f. Mul. BioI.. 9, 154 (1964). '\" Hardesty, B., Hutton, J. J. , Arlinghuus, R., and Schwcet, R., 1\"(0('. U.s. Nat. Acad. Sci., 50, 1078 (1963). 11 Spyrides , G. J., an.d Lipmann, F., Proc. U.S. ;.. Vat. Acad. Sci. , 48 . 1977 (1962). .. liarondes, S. H., and Nirenberg, ~L W., Sci\",,,e, 138, 813 (1962). 13 Gilbert, W., J. Mol. Bioi. , 6, 374 (1963) . ,. Hardesty, B., Arllnghaus, R ., Schaeffer, J., and Sehweet, R. S., Cold Sprin;] Harbor Symp. Quant. Bioi., 28, 215 (1963). 11 Ra.,chemeyer, A. E. V., and Rich, A. , Biochim. B-iophys. A cta , 55, 9U (1962). .. Bishop, J. 0., Nature, 202, 86 (1964). n J31shop, J. 0., Nature, 203,40 (1964). \"Allcn, E. H., and Sehweet, R. S., .!. Bioi. Chern., 237 , 760 (1962). \" Monicr, Ro, Stephenson, JI{. L., and Zamecnik, P. C., Rim·him. Bi
521 citations
TL;DR: A novel synthesis route has been developed to produce a high-purity mixed AB-type carbonate-substituted hydroxyapatite (CHA) with a carbonate content that is comparable to the type and level observed in bone mineral.
Abstract: A novel synthesis route has been developed to produce a high-purity mixed AB-type carbonate-substituted hydroxyapatite (CHA) with a carbonate content that is comparable to the type and level observed in bone mineral. This method involves the aqueous precipitation in the presence of carbonate ions in solution of a calcium phosphate apatite with a Ca/P molar ratio greater than the stoichiometric value of 1.67 for hydroxyapatite (HA). The resulting calcium-rich carbonate-apatite is sintered/heat-treated in a carbon dioxide atmosphere to produce a single-phase, crystalline carbonate-substituted hydroxyapatite. In contrast to previous methods for producing B- or AB-type carbonate-substituted hydroxyapatites, no sodium or ammonium ions, which would be present in the reaction mixture from the sodium or ammonium carbonates commonly used as a source of carbonate ions, were present in the final product. The chemical and phase compositions of the carbonate-substituted hydroxyapatite was characterized by X-ray fluorescence and X-ray diffraction, respectively, and the level and nature of the carbonate substitution were studied using C-H-N analysis and Fourier transform infrared spectroscopy, respectively. The carbonate substitution improves the densification of hydroxyapatite and reduces the sintering temperature required to achieve near-full density by approximately 200 degrees C compared to stoichiometric HA. Initial studies have shown that these carbonate-substituted hydroxyapatites have improved mechanical and biologic properties compared to stoichiometric hydroxyapatite.
472 citations
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