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EN
Bone fractures are one of the most commonly seen problems in veterinary traumatology. The authors of this study strive to find a new intramedullary nail, which is intended for treating femoral bone fractures for canine patients. The purpose of this study was to analyze biomechanical parameters of the intramedullary nails, which use a new bolt system concept. Methods: Dissected femoral bones of a large breed dog were cut in order to simulate interfragmentary gap, and then the bones were stabilized using intramedullary nail with locking bolts. Bone-nail systems were subjected to cyclic loading using force which corresponds to the load on the femoral bone in the first few days after surgery. Micro-CT scans were taken of the bone samples around implant in order to determine deformation and structural parameters of bone tissue. Results: The calculation of the bone-nail system stiffness was done through analysis of the forcedisplacement curves recorded during experimental studies. Using monocortical locking bolts resulted in smaller stiffness of the bone-nail system than using bicortical locking bolts. Conclusions: The results obtained in this study can indicate that the intramedullary nail could work well when used for treatment of bone fractures in dogs. The authors focused on using monocortical bolts which provides good stability and adequate biomechanical environment. Described fixation method is easily adjustable to a particular patient individual parameters.
EN
Bioresorbable materials are used in medicine for fixing, correcting or stabilizing bones in various anatomical areas, and the market for such materials is growing rapidly worldwide. The use of polymers for their production is associated with the ability to control their properties. They are prepared from bioresorbable materials with variable surface, geometry, porosity, as well as mechanical and surface properties. They support bone healing and are suitable for tissue regeneration due to their biodegradability and biocompatibility. We believe that materials from biodegradable polymers will play an increasingly important role in future medicine.
PL
Materiały bioresorbowalne są szeroko stosowane wmedycynie do uzupełniania ubytków kości w różnych stanach chorobowych i powypadkowych, a także do nadbudowy iodbudowy kostnej oraz mocowania złamań. Rynek tego typu materiałów szybko się rozwija na całym świecie. Powszechność wykorzystania polimerów jest związana z możliwością kontrolowania ich właściwości. Zaletą materia-łów polimerowych jest możliwość zmiany powierzchni, geometrii, porowatości, właściwości mechanicz-nych ipowierzchniowych, atakże ich biodegradowalność ibiokompatybilność. Materiały z polimerów biodegradowalnych będą zapewne odgrywać coraz poważniejszą rolę w medycynie przyszłości.
EN
Irradiations of poly(lactic-co-glycolic acid) surface by CO2 laser lead to alterations of physicochemical properties of the copolymer. Effects of PLGA irradiations depend on the process parameters determining different cases of surface modification. Hence the main goal of presented studies was to define the influence of CO2 laser irradiation with different process parameters, inducing three cases of surface modification, on mechanical properties and topography of PLGA during degradation in the aqueous environment. Methods: Hydrolytic degradation of untreated and treated by CO2 laser thin specimens of PLGA was performed in distilled (demineralized) water. Mechanical properties of PLGA specimens before and during incubation were conducted in accordance with the PN-EN ISO 527-3:1998 standard. The pH of incubation solutions, topographies, masses and geometrical dimensions of specimens were controlled during the process. Results: During the hydrolytic degradation, gradual changes in failure mode were observed from ductile failure characteristic for untreated PLGA to brittle failure of incubated PLGA regardless of the case of induced modification. Tensile strength decreased with degradation time regardless of the case of surface modification with insignificant fluctuation Young’s moduli at the level of means. The pH of solutions for each case decreased and topography od specimens become smoother with incubation time. Conclusions: PLGA surface modification by CO2 laser below the ablation threshold (P1) and at the ablation threshold (P2) led to surface functionalization, however, irradiation above the ablation threshold (P3) caused marked degradation of PLGA and accelerated specimens disintegration during incubation in the aquatic environment.
EN
The aim of the presented work is to determine (i) mechanical properties of the ascending aorta wall (DAA) and the wall of the ascending aortic aneurysm (DAAA), in which spontaneous dissection resulting from the evolving disease occurred, and (ii) the strength of the interface between the layers in the above-mentioned vessels. Methods: The mechanical tests were divided into two steps. In the first step the mechanical properties of the of DAA and DAAA walls were examined on the basis of uniaxial stretching until rapture. In the next step the mechanical parameters of the interface between layers of DAA and DAAA walls were determined by the peeling test. Results: Higher values of tensile strength (max) and Young’s modulus (E) were obtained for the DAAA group, to which the dissecting wall of the ascending aortic aneurysm was classified. For circumferential samples, the difference between the DAAA and DAA groups was 39% in the case of tensile strength and 70% in the case of the Young’s modulus. Conclusions: Summarizing, the studies performed showed that the dissection process is different in the case of the ascending aortic aneurysm wall and the ascending aorta wall. The wall of the ascending aortic aneurysm is more susceptible to dissection, as evidenced by lower values of the mechanical parameters of the interface between the intima and the media-adventitia complex. The obtained results of mechanical properties tests confirm that dissection and aneurysm should be treated as separate disease entities that may coexist with each other.
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