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Wyszukujesz frazę "Cieślicki, K." wg kryterium: Autor


Wyświetlanie 1-3 z 3
Tytuł:
Experimental and numerical modelling of flow in the human cerebral arteries
Autorzy:
Cieślicki, K.
Powiązania:
https://bibliotekanauki.pl/articles/333722.pdf
Data publikacji:
2004
Wydawca:
Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:
koło tętnicze Willisa
tętnice mózgowe
model fizyczny
circle of Willis
cerebral arteries
physical model
nonlinearity of flow
Opis:
The paper presents the results of experiments concerning flow in the model of cerebral supplying arteries and the Circle of Willis (CW). Vascular phantom was prepared on the basis of anatomical specimens. The most typical artery shapes and dimensions were considered. Pressure distribution in 6 characteristic points is provided, and so are the average flow rates in the anterior, middle and posterior section of the brain. Tests were run in the conditions replicating the physiological state (i.e. when the supplying arteries were fully patent) and in pathological conditions, in which the internal carotid and vertebral arteries were occluded on one or both sides. Thus obtained results were compared with the results of computer simulations based on linear and non-linear flow models. To estimate the non-linear resistance of vascular segment two phenomenological formulae were proposed. High degree of correlation between the values obtained from experiments and those registered in non-linear computer model proves usefulness of proposed formulae. It verifies the hypothesis that nonlinearity of flow characteristics of the vessel segments is to a great extent caused by their tortuous and small length in relation to diameter. Non-linear effects are particularly pronounced in conditions of pathological occlusion of supplying vessels.
Źródło:
Journal of Medical Informatics & Technologies; 2004, 7; IP17-26
1642-6037
Pojawia się w:
Journal of Medical Informatics & Technologies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reversed Robin Hood syndrome in the light of nonlinear model of cerebral circulation
Autorzy:
Piechna, A.
Cieslicki, K.
Powiązania:
https://bibliotekanauki.pl/articles/264358.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
cerebral blood flow
autoregulation
steal syndrome
circle of Willis
Computational Fluid Dynamics (CFD)
autoregulacja
przepływ krwi w mózgu
tętnica
Opis:
The brain is supplied by the internal carotid and vertebro-basilar systems of vessels interconnected by arterial anastomoses and forming at the base of the brain a structure called the Circle of Willis (CoW). An active intrinsic ability of cerebral vascular bed maintains constant Cerebral Blood Flow (CBF) in a certain range of systemic pressure changes. This ability is called autoregulation and together with the redundant structure of the CoW guarantee maintaining CBF even in partial occlusion of supplying arteries. However, there are some situations when the combination of those two mechanisms causes an opposite effect called the Reversed Robin Hood Syndrome (RRHS). In this work we proposed a model of the CoW with autoregulation mechanism and investigated a RRHS which may occur in the case of Internal Carotid Artery (ICA) stenosis combined with hypercapnia. We showed and analyzed the mechanism of stealing the blood by the contralateral side of the brain. Our results were qualitatively compared with the clinical reports available in the literature.
Źródło:
International Journal of Applied Mechanics and Engineering; 2017, 22, 2; 459-464
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ex vivo and in silico study of human Common Carotid Arteries pressure response in physiological and inverted state
Autorzy:
Piechna, A.
Cieślicki, K.
Lombarski, L.
Ciszek, B.
Powiązania:
https://bibliotekanauki.pl/articles/265143.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
artery mechanics
residual stress
pressure-inflation test
common carotid artery
tętnica szyjna
metoda elementów skończonych
symulacja komputerowa
Opis:
Arterial walls are a multilayer structures with nonlinear material characteristics. Furthermore, residua stresses exist in unloaded state (zero-pressure condition) and they affect arterial behavior. To investigate these phenomena a number of theoretical and numerical studies were performed, however no experimental validation was proposed and realized yet. We cannot get rid of residual stresses without damaging the arterial segment. In this paper we propose a novel experiment to validate a numerical model of artery with residual stresses. The inspiration for our study originates from experiments made by Dobrin on dogs’ arteries (1999). We applied the idea of turning the artery inside out. After such an operation the sequence of layer is reversed and the residual stresses are re-ordered. We performed several pressure-inflation tests on human Common Carotid Arteries (CCA) in normal and inverted configurations. The nonlinear responses of arterial behavior were obtained and compared to the numerical model. Computer simulations were carried out using the commercial software which applied the finite element method (FEM). Then, these results were discussed.
Źródło:
International Journal of Applied Mechanics and Engineering; 2015, 20, 1; 209-214
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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