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In vitrotests of dense hydroxyapatite materials

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EN
The paper presents the results of the calcining process of deproteinised and defatted bone pulp called bone sludge. The calcining process was performed in two stages. The first step of the calcining process was realized at the temperature of 600°C in a rotary kiln. In the second stage the obtained bone ashes were calcined at five different temperatures from 650°C to 950°C for 2 hours in a chamber kiln and in air atmosphere. The products of the calcining process were characterized by the XRD method. Calcium content was determined by titration whereas the contents of total phosphorus and acid-soluble phosphorus - by the spectrophotometric method. The X-ray analysis confirmed that hydroxyapatite is the main component of the calcining products. Calcium and phosphorus contents were kept at the level of 40% and 17.5%, respectively, which corresponded to the Ca/P ratio of not stechiometric hydroxyapatite. In vitro studies, in the simulated body fluid, Ringer liquid and distilled water were realised. The measurements of pH value of SBF and Ringer fluid were realized. Additionally electrical conductivity as well as pH for distilled water where conducted. The goal of these tests was to evaluate chemical durability of dense hydroxyapatite materials.
EN
The method of obtaining hydroxyapatite by thermal treatment of deproteinised and defatted bone pulp called bone sludge was presented. The products of the calcining process were characterized with X-ray diffraction (XRD) and Fourier transformed infrared spectroscopy (FT-IR). The calcium content was determined with titration, whereas the contents of total phosphorus - with a spectrophotomertric method. X-ray investigations confirmed that hydroxyapatite was the main component of the calcining products in the calcining process. The FT-IR spectra confirmed that all organic substances were removed during the calcining process. On the basis of the research into physiological liquids the propensity to resorption of hydroxyapatite bioceramic was evaluated.
EN
Ceftiofur sodium (CFT), a third-generation cephalosporin for parenteral use, is commonly used in veterinary medicine against aerobic Gram-positive and Gram-negative bacteria as well as certain anaerobes. Its broad spectrum of activity and resistance to beta-lactamases result from the presence of methoxyimino and aminothiazole moieties at C-7 in the cephalosporin structure. The aim of this study was a comprehensive evaluation of the stability of CFT in the solid phase and in aqueous solutions. A fast and sensitive HPLC isocratic method was used for the determination of CFT degradation in the solid phase and in aqueous solutions. CFT degradation occurred according to a first-order reaction depending on the substrate concentration. The kinetic and thermodynamic parameters of CFT degradation in the solid phase were calculated. General acid-base hydrolysis of CFT was not observed in the solutions of hydrochloric acid, sodium hydroxide, phosphate (pH 5.84 – 7.25), acetate (pH 3.65 – 5.48) and borate (pH 7.49 – 10.07) buffers. CFT was the most stable in the pH range 2 – 6. The susceptibility of CFT to degradation under the influence of stress factors (pH, temperature, buffer components concentration, relative air humidity) should be considered in terms of storage conditions and the preparation of the product for administration.
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