Redes epóxi/amina alifáticas com perspectivas para aplicações cardiovasculares. Propriedades biológicas in vitro

Este trabalho descreve as propriedades biológicas in vitro de três redes epoxídicas à base do éter diglicidílico do glicerol (DGEG) curadas com poli(oxipropileno) diamina (D230), isoforona diamina (IPD) e 4,4'-diamino-3,3'-dimetil-diciclohexilmetano (3DCM). As interações biológicas entre os polímeros e o sangue foram estudadas por ensaios biológicos in vitro. Estudos de adsorção de proteínas, adesão de plaquetas, atividade do lactato desidrogenase (LDH) e propriedades de tromboresistência estão apresentados. Os ensaios de adsorção de proteínas na superfície dos polímeros mostrou que as redes epoxídicas adsorvem mais albumina do que fibrinogênio. Os resultados relacionados à adesão de plaquetas, atividade do lactato hidrogenase e propriedades de tromboresistência indicaram que as redes DGEG/IPD e DGEG/3DCM exibem comportamento hemocompatível. Desta maneira, assumimos que estes polímeros epoxídicos são materiais compatíveis com o sangue

Geoarchaeology and castlescapes: heritage management case studies in Spain and the eastern Baltic

This paper promotes the application of geoarchaeology—joint studies using historical, archaeological and heritage approaches—to the conservation and management practice of castles and landscapes in the context of ‘castlescapes’. Using case studies from recent research on medieval castles in frontier regions of the eastern Baltic and Spain, it demonstrates how geoarchaeology can create synergies between on-site and off-site environments and between cultural and natural heritage and draw valuable information from soils and sediments about the changing form and function of spaces within castles, and about the links between these spaces and activities in their hinterlands. Geoarchaeological approaches can also illuminate the diachronic biographies that hide from visitors in the buried archaeology of castles, which to most visitors would be blank cavasses, but which can provide snap-shots of castle life in the context of a wider landscape. Castles are commonly publicly recognised as being important historical monuments, but from a heritage perspective they are often presented in isolation from their associated historical territories, and often (especially in frontier regions) appropriated within modern politics, which has influenced both heritage management decisions and research frameworks

Biomechanical analysis of individual all-ceramic abutments used in dental implantology

Biomechanical analysis of individual all-ceramic abutments used in dental implantology The paper presents the results of finite element analysis and experimental testing under simulated physiological loading conditions on issues shaping the functional properties of individual all-ceramic abutments manufactured by CAD'CAM technology The conducted research have cognitive significance showing the all-ceramic abutment behavior, as a key element of the implantological system, under the action of cyclic load. The aim of this study was evaluation the fatigue behavior of yttria-stabilized zirconia abutment submitted to cyclic stresses, conducted in accordance with EN ISO 14801 applies to dynamic fatigue tests of endosseous dental implants

Mechanical properties of femoral bovine bones with varying degrees of hydration

Celem pracy było określenie własności wytrzymałościowych bydlęcych kości udowych o różnym stopniu uwodnienia. Podczas realizacji pracy przeprowadzono statyczną próbę trójpunktowego zginania oraz statyczną próbę jednoosiowego ściskania. W konsekwencji wyznaczono wartości wytrzymałości na zginanie oraz ściskanie wszystkich grup badawczych. Stwierdzono, że zarówno stopień uwodnienia, jak i kierunek pobierania próbek znacząco wpływa na wartości własności wytrzymałościowych.The aim of the study was determinate the mechanical properties of femoral bovine bones with varying degrees of hydration. During the execution of the work conducted the static three-point bending test and a static uniaxial compressive test. Consequently, were determine the values of bending strength and ultimate compressive strength for the all research groups. It was stated that the degree of hydration and direction of sampling significantly alters the studies strength parameters

Experimental biomechanical assessment of plate stabilizers for treatment of pectus excavatum

The paper discusses results of experimental research involving new generation of plate stabilizers used for the treatment of deformation of the front chest wall. Previous clinical monitoring revealed instances of minimal rotation, which caused destabilization of the anastomosis and pain in patients. In order to prevent this, transverse stabilizing plates were introduced to the structure of the stabilizer. The new structure of stabilizers was tested using two specially prepared research posts: 1 – which enables fastening of the plate stabilizers to a platform simulating human ribs, 2 – using a pig chest, to which plates were fastened according to the stabilization conditions in the stabilizer–chest structure. The tests recorded displacement values in selected areas of the plates in response to applied loading forces

The measurement of school-age children chest stiffness

W artykule przedstawiono metodę oceny sztywności klatki piersiowej u dzieci w wieku szkolnym. Wykonane pomiary pozwoliły określić siłę nacisku przy ustalonym ugięciu klatki piersiowej oraz wyznaczyć na tej podstawie jej elastyczność. Badania sztywności klatki piersiowej przeprowadzono w poszczególnych grupach wiekowych dzieci w wieku szkolnym. Otrzymane wyniki pomiarów sztywności klatki piersiowej w poszczególnych grupach wiekowych, umożliwiają na optymalne dobranie parametrów geometrycznych płyt stabilizujących stosowanych do korekcji.The method of measurement of school-age children chest stiffness was presented in the article. The measurements are shown in this work were conducted for children 9-13 years old. From biomechanical point of view, the knowledge of chest stiffness value affecting the stabilizer is necessary to select optimal parameters of the plate used for correction of deformation of the chest by Nuss‟ method

Studies of the Corrosion Resistance Properties of Bone Screws Made from 316L Stainless Steel in Ringer's Solution

Stainless steel 316L is one of the most common metallic biomaterials used for implants. Its passive surface provides a good corrosion resistance in the body environment, which can be reduced by surface mechanical damages. This is the reason why the bone screws made of stainless steel 316L were subjected to laboratory analysis in the initial state, after diversified implantation period and after mechanical damage of the surface. The mechanical damages were estimated on the basis of stereoscopic and scanning electron microscope (SEM). In order to estimate the pitting and crevice corrosion resistance, potentiodynamic and potentiostatic examinations were performed. On the basis of obtained results it can be stated that despite the visible damages on the surface, the investigated screws present a good pitting corrosion resistance. However, the way the screws were fastened caused frictional corrosion and existing cavities led to crevice corrosion. Moreover, clear correlation between magnitude of mechanical damages of the surface, implantation time and screws corrosion resistance was observed