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The intima with early atherosclerotic lesions is load-bearing component of human thoracic aorta

Kobielarz M., Kozuń M., Kuzan A., Maksymowicz K., Witkiewicz W., Pezowicz C.

Biocybernetics and Biomedical Engineering

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2017

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Vol. 37, no. 1

35--43

EN

The aim of the study was to evaluate the mechanical properties of the adventitia, media, and especially intima of the human thoracic aortic wall in the early stages of atherosclerosis (stage I to III according to the Stary's classification). Histological and immunohistochemical techniques were used to evaluate the severity of atherosclerosis and the correctness of separation of the respective layers. Circumferential specimens of the adventitia, media, and intima (n = 193) were prepared from 27 arteries. The mechanical properties, i.e. the ultimate tensile strength, the maximum strain, and the maximum tangential elastic moduli, were determined in uniaxial tensile test and presented as a median (Me). The tensile strength of the intima (Me = 105 kPa) is comparable to the media (Me = 123 kPa) and lower than for the adventitia (Me = 808.5 kPa). The intima also undergoes the lowest maximum strain (Me = 0.008), and its elastic modulus (Me = 11510 kPa) is significantly higher compared to the media (Me = 5280 kPa). Therefore, presented results indicate that even in the early stages of atherosclerotic development the intima takes part in the process of mechanical loads bearing.

2

Delamination properties of the human thoracic arterial wall with early stage of atherosclerosis lesions

Kozuń M.

Journal of Theoretical and Applied Mechanics

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2016

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Vol. 54 nr 1

229--238

EN

The aim of this work is to determine mechanical properties of interfaces between layers of the human thoracic aortic wall with early stages of atherosclerosis lesions. Circumferential (n = 48) and axial (n = 15) specimens have been prepared and the mechanical properties of the interfaces between the layers have been determined on the basis of the peeling test. The results show that the mechanical and dissection properties of the interfaces between the layers depend on the direction of the tests. The results confirm that the early stage of atherosclerosis does not affect the mechanical parameters of the layer interfaces and does not affect resistance of the vessel wall to delamination.

3

Właściwości mechaniczne tkanki kostnej gąbczastej zmienionej patologicznie

Kozuń M., Nikodem A.

Aktualne Problemy Biomechaniki

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2011

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z. 5

69--74

PL

W pracy przedstawiono wyniki pomiarów gęstości fizycznej oraz wartości parametrów mechanicznych wyznaczonych w próbie jednoosiowego ściskania dla próbek tkanki kostnej gąbczastej osteoartrotycznej, pochodzących z głów ludzkich kości udowych. W pracy podjęto także próbę określenia korelacji pomiędzy gęstością fizyczną, a parametrami mechanicznymi tkanki kostnej. Gęstość fizyczna oraz parametry mechaniczne tkanki kostnej charakteryzują się najwyższą wartością dla próbek wyciętych z plastra II. Znaleziono również wysoką korelację pomiędzy gęstością hydrostatyczną, a modułem Young'a (R² = 0,53).

EN

The puproses of this study were to evaluate the mechanical properties of human patological trabecular bone from adult human femoral heads removed during surgery for hip-joint replacement and to measure bone densities. The correlations between the mechanical properties and bone densities were also considered. The results showed that mechanical properties of the specimens from region II are higher than those obtained from region I. The correlation between the bone density and mechanical properties is high (R² = 0,53).