Wyniki 1-4 spośród 4 dla zapytania: authorDesc:"ANNA MARIA JANUS"

Influence of sintering temperature on morphology of dense bioceramics based on hydroxyapatite derived from porcine bones

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Hydroxyapatite (HAp - Ca10(PO4)6(OH)2) is the major constituent of mineral phase of human bone. It characterizes itself with high biocompatibility and has been used in medicine and stomatology for more than 20 years [1]. Hydroxyapatite can be obtained either by synthesis or by extraction from natural sources. Commercially available hydroxyapatite materials are listed in Table 1. Hydroxyapatite derived from porcine bones has not been commercialized yet, thus its development seems to be an attractive field of research. Biocompatibility of hydroxyapatite of porcine origin has been proved under in vitro and in vivo conditions [2, 3]. Heat treatment significantly influences chemical composition of the regarded hydroxyapatite derived from the animal bone. Such observation is proved by the other investigators [4, 5]. The information, found in literature and concerning influence of the sintering conditions on the dense bioceramics biocompatibility, however, do not cover all possible sintering conditions [5÷8]. The aim of the presented work was to examine the influence of the temperature of sintering process on the hydroxyapatite morphology. The properties of the investigated materials were afterwards subject of in vitro biocompatibility investigation. MATERIALS AND METHODS Hydroxyapatite of porcine origin was obtained from long porcine bones. Preparation procedure comprised bones boiling in distilled water for 24 h, mechanical removal of tissue and spongy parts residues, leaching out of organic matter with 4 M sodium hydroxide solution during 48 h at 100°C, rinsing with distilled water in order to remove NaOH, drying at 120°C to constant mass, milling, sieving and calcination at 450°C in atmosphere of air for complete removal of organic matter. As reference material HA BIOCER synthetic hydroxyapatite from Chema-Elektromet (Pola[...]

Preparation of phosphate glass reinforced hydroxyapatite scaffolds for tissue engineering

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Hydroxyapatite (HAp) is the mineral of human bone. HAp is biocompatible and osteoconductive revealing an excellent chemical and biological affinity with bony tissues. The long-term biocompatibility of solid HAp and its favorable interaction with soft tissue and bone are widely acknowledged. These properties make HAp an excellent starting material for preparation of scaffolds for tissue engin[...]

Environmental Scanning Electron Microscopy and image analysis techniques in biocompatibility investigations of hydroxyapatite of pig origin

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Hydroxyapatite (HAp - Ca10(PO4)6(OH)2) is a well known biomaterial. Various HAp biomaterials (synthetic as well as of natural origin) are commercially available. HAp of pig origin is not commercially available yet. This paper describes application of Environmental Scanning Electron Microscopy (E-SEM) and image analysis techniques in vitro biocompatibility investigations of HAp of pig origin. [...]

Ultrasonic method applied to defects identification in the forging ingots

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The typical massive forging ingots produced in the steelwork has a mass of about 10÷100 T (Fig. 1). According to the technology of casting a porosity is expected along the ingot axis (Fig. 2). Each forging ingot is subjected to an ultrasonic test at a production line. But the result of this kind of industry test are not evident. In the case of the ingot of the mass about 12 T the acoustic signal indicated porous less than 1 mm longue (reduced distance). However, in the case of the ingot of the mass about 50 T the acoustic signal was completely damped by the grains boundaries so that no results of acoustic measurement were obtained. Therefore, some additional tests have been made by means of the light microscopy (LM) and scanning acoustic microscopy (SAM) for six samples along a given radius of the ingot shown in Figure 1. EXPERIMENTAL The results of the microstructure observation are shown in Fig. 3. A morphology of a one defect can be shown in more details (Fig. 4). The light microscopy is not able to reveal all the details of morphology of some single defects as these shown in Figures 3 and 4. Therefore, an attempt to identify the details of some defects was done by the scanning acoustic microscopy (Fig. 5, 6, 7a). Identification of the defects is performed by the SAM technique through density analysis of the different sample sublayers (Fig. 6). Microscope reveals a defect by comparison of the difference between density of bulk sample and density of a given defect. It is possible because scans can be made at different fixed distances. ˗ Fig. 1. Massive forging ingot produced in the steelwork Rys. 1. Masywny wlewek kuzienny produkcji hu[...]

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