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An analysis of the effect of impact loading on the destruction of vascular structures in the brain

Ratajczyk M., Sąsiadek M., Będziński R.

Acta of Bioengineering and Biomechanics

2016

Vol. 18, no. 3

21--31

Subdural hematomas are one of the frequent complications of head injuries. Such hematomas result from exceeding the border strength values of bridging veins. Subdural haemorrhages are life-threatening and are a frequent cause of considerable pathologies. Traffic participants and also soldiers who participate in armed conflicts are the most vulnerable to head injuries. Although hematomas have been studied for many years the mechanism of hematoma formation has not been fully clarified as yet. In the paper, the effort of brain tissue structures due to the propagation of shock wave was analyzed. Particular attention was paid to the deformation ability and changes in the energy of bridging veins. This research was concerned with changes in mechanical properties of these veins in the frontal, parietal and occipital regions of the brain. For the present research the authors have constructed finite element models of brain tissue fragments and conducted numerical studies taking into account the boundary conditions arising from violent overloads that result from combat operations. As a result of the numerical analysis conducted, critical values of strain and stress have been obtained. The analysis showed high diversity in the properties of the different regions of the brain tissue. The studies carried out by the authors rendered it possible to assess the effort of the tissue structures of veins in connection with mechanical parameters, including geometrical parameters, in particular in relation to the likelihood of hematoma formation.

Biomechanical properties of the thin PVD coatings defined by red blood cells

Trembecka-Wojciga K., Major R., Lackner J. M., Bruckert F., Jasek E., Major B.

Bulletin of the Polish Academy of Sciences. Technical Sciences

2015

Vol. 63, nr 3

697--705

The measurement of the strength of bonds between biomaterials and cells is a major challenge in biotribology since it allows for the identification of different species in adhesion phenomena. Biomaterials, such as diamond-like carbon (DLC), titanium, and titanium nitride, seem to be good candidates for future blood-contact applications. These materials were deposited as thin films by the hybrid pulsed laser deposition (PLD) technique to examine the influence of such surfaces on cell behavior. The biomaterial examinations were performed in static conditions with red blood cells and then subjected to a dynamical test to observe the cell detachment kinetics. The tests revealed differences in behavior with respect to the applied coating material. The strongest cell-biomaterial interaction was observed for the carbon-based materials compared to the titanium and titanium nitride. Among many tests, a radial flow interaction analysis gives the opportunity to analyze cell adhesion to the applied material with the high accuracy. Analysis of concentrates helped to select materials for further dynamic tests on blood using an aortic flow simulator. In this case, the platelet adhesion to the surface and their degree of activation was analyzed. The quality of the selected coating was tested using a scratch test. The analyses of the microstructure were done using high resolution transmission electron microscopy. The phase composition and the residual stress were analyzed using X-ray diffraction methods.

Poziom rozwijanego statycznego momentu siły a wysokość skoku CMJ studentów AWF we Wrocławiu

Struzik A., Pietraszewski B.

Aktualne Problemy Biomechaniki

2010

z. 4

179--184

W pracy poszukiwano związku między statycznym momentem siły prostowników i zginaczy stawu kolanowego (sumy prostowników i sumy zginaczy) a wysokością skoku CMJ. Rejestracji sił reakcji podłoża dokonano używając platformy dynamometrycznej firmy Kistler i oprogramowania BioWare. Badania przeprowadzono na grupie 30 studentów IV roku AWF we Wrocławiu w Pracowni Analiz Biomechanicznych. Badanymi były osoby uprawiające sport wyczynowo od minimum 5 lat. Badania miały na celu ocenę własności biomechanicznych (mierzonych w działaniach statycznych i dynamicznych) kończyn dolnych człowieka.

The purpose of the research was to determine the relationship between the static moment of force of knee joint flexors and extensors (sum of flexors and sum of extensors) and the height of CMJ jump. Dynamometric Kistler plate and BioWare software were applied to record the ground reaction force. 30 University School of Physical Education students participated in the study. The research was conducted in the Laboratory of Biomechanical Analysis in Wroclaw. Subjects have been performing professional sport no less than 5 years. The purpose of the research was to assess the biomechanical properties of the lower limbs (measured during static and dynamic exercises).