ABSTRACT
Calcium phosphate cement (CPC) samples have been prepared with a mixture of monocalciumphosphate monohydrate (MCPM) and calcium carbonate (CC) powders, in stechiometric moles ratio 1:2.5 to obtain a Ca/P ratio of about 1.67 typical of hydroxyapatite (HAp), with or without addition of HAp. All specimens are incubated at 30 degrees C in a steam saturated air environment for 3, 6 and 15 days respectively, afterwards dried and stored under nitrogen. The calcium phosphate samples have been characterized by X-ray diffraction (XRD), Vickers hardness test (HV), diametral compression (d.c.), strength compression, and porosity evaluation. MCPM/CC mixture has a 30% HAp final concentration and is characterized by higher porosity (amount 78%) and mechanical properties useful as filler in bone segments without high mechanical stress.
Subject(s)
Biocompatible Materials/chemical synthesis , Calcium Phosphates/chemical synthesis , Bone Cements , Bone Substitutes , Calcium Carbonate/chemistry , Calcium Phosphates/chemistry , Durapatite/chemistry , Manufactured Materials/analysis , Powders/chemical synthesis , Powders/chemistry , X-Ray DiffractionABSTRACT
The HPLC method here described allows to separate CNBr collagen peptides within 2.5 h by reversed phase and gradient elution. The method is useful to determine both peptide bond and pyridinoline groups by absorbance spectophotometry. The fractions can be recovered and then submitted to other characterization techniques.
Subject(s)
Amino Acids , Chromatography, High Pressure Liquid/methods , Collagen/chemistry , Cyanogen BromideABSTRACT
The paper describes thermoanalytical data obtained from rat limb bones by TG, DTG and DSC. Analyses were performed on bone samples from femurs, tibiae and humeri, either crude and extracted with acetone and/or sodium dodecylsulphate. The DSC curves show an endothermic reaction at 85 degrees C and a sharp exothermic peak at 337 degrees C, followed by an exothermic profile between 350 degrees-650 degrees C. Mean weight changes are: 34.28% total weight loss (25 degrees-800 degrees C); 7.33% water loss (25 degrees-200 degrees C); 26.21% organic loss (200 degrees-800 degrees C). Thermal analysis on diaphyseal and epiphyseal bone samples evidences an organic content of 24.54% for diaphyseal compact bone tissue and of 30.62% for epiphyseal trabecular bone tissue (p < .005). The values obtained from different bones and by different treatment of samples are compared.
