Hydroxyapatite microcrystalline

Valsami-Jones et al. (1998) conducted similar studies with a synthetic, microcrystalline hydroxyapatite in either a Pb or Cd buffered solution. Using AFM, hydroxypyromorphite was observed to grow epitaxially on the hydroxyapatite surface in a clear example of heterogeneous nucleation. Cd removal differed, with the likely formation of a Ca-Cd phosphate solid solution. 

Boskey, A. L., Posner, A. S. Conversion of amorphous calcium phosphate to microcrystalline hydroxyapatite pH-dependent, solution-mediated, solid-solid conversion. J. Phys. 

Hydroxyapatite chromatography, separating molecules by differential surface binding to phosphate and calcium sites on a microcrystalline matrix of hydroxyapatite ([Ca5 (P04) 3OH] 2)... 

It was stated that hydrated calcium monohydrogen phosphate in amorphous or cryptocrystalline form is a potential precursor in the formation of hydroxyapatite because the structural position of Ca2+ on (010) and (110) crystal planes of both minerals essentially correspond to one another492. These planes of calcium ions could easily serve as transition boundaries with little distortion of crystal structure the same holds true for octacalcium phosphate or defect apatites. Thus apatite may form from amorphous or microcrystalline calcium monohydrogen phosphate possible via octacalcium phosphate or defect apatites. This process may already start inside the matrix vesicles and continue during extravesicular activities. 

Adsorption chromatography usually employs microcrystalline hydroxyapatite columns that adsorb proteins vmder conditions above pH 5. Gradient or step-wise elution with increasing concentration of eluting agent in the mobile phase may be used to release the enzyme required. 

A different inorganic column support material, based on microcrystalline hydroxyapatite (HA), Caio(P04)6(OH>2, is thought to be c ble of handling much larger proteins,... 

As it is only relatively recently that techniques have been found to produce microcrystalline hydroxyapatite with a narrow particle size distribution suitable for HPLC, the selection available is still small. The more familiar ones are summarized in Table 6. 

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