- Eklemek veya çıkarmak istediğiniz kriterleriniz için 'Dahil' / 'Hariç' seçeneğini kullanabilirsiniz. Sorgu satırları birbirine 'VE' bağlacı ile bağlıdır. - İptal tuşuna basarak normal aramaya dönebilirsiniz.
A series of novel orthopedic calcium phosphate (CaP+CaCO3) cements have been developed. The common point in these cements was that they all utilized single-phase CaCO3 (calcite or vaterite) in their powder components. The major phase in the end-product of these cements was carbonated, Ca-deficient, apatitic calcium phosphate, together with some varying amounts of unreacted CaCO3. Calcite powders used were needle-like or acicular in shape, whereas the vaterite powders were monodisperse, and spherical or ellipsoidal in shape. A new method for synthesizing spheroidal vaterite powders has also been developed. Setting solutions for calci . . .te-based cement scaffolds were prepared by acid-base neutralization of concentrated H3PO 4 and NaOH. 0.5 M phosphate buffer solution was used to transform precipitated vaterite powders into CaP at 37° to 70°C. Setting solutions possessed pH values ranging from 3 to 7.4 at room temperature. Resultant cements were micro- (5 to 50 micron pores) and macroporous (200 to 700 micron pores). In the macroporous cements, total porosity was variable from 20 to 45%. Setting times of those cements were adjustable over the range of 12 to 25 minutes. Compressive strengths of these cements varied from 2 to 3 MPa, depending on their porosity. CaP+CaCO3 cements thus obtained had relatively high surface areas (30 to 85 m2/g) whose surfaces were covered with nanocrystallites similar in size to the nanoplatelets found in biological collagen-calcium phosphate composites. Cement scaffolds were characterized by XRD, FTIR, SEM, ICP-AES, surface area and compressive strength measurements