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991.
Tomasz Plonek Malgorzata Zak Karolina Burzynska Bartosz Rylski Anna Gozdzik Wojciech Kustrzycki Friedhelm Beyersdorf Marek Jasinski Jaroslaw Filipiak 《BMC cardiovascular disorders》2017,17(1):297
Background
Biomechanical factors influence stress in the aortic wall. The aim of this study was to assess how the diameter and shape of the vessel, blood pressure and longitudinal systolic aortic stretching (SAS) caused by the contraction of the myocardium influence stress in the aortic wall.Methods
Three computational models of the non-dilated aorta and aneurysms of the ascending aorta and aortic root were created. Then, finite elements analyses were carried out. The models were subjected to blood pressure (120 mmHg and 160 mmHg) and longitudinal systolic aortic stretching (0 mm, 5 mm, 10 mm and 15 mm). The influence of wall elasticity was examined too.Results
Blood pressure had a smaller impact on the stress than the SAS. An increase in blood pressure from 120 mmHg to 160 mmHg increased the peak wall stress (PWS) on average by 0.1 MPa in all models. A 5 mm SAS caused a 0.1–0.2 MPa increase in PWS in all the models. The increase in PWS caused by a 10 mm and 15 mm SAS was 0.2 MPa and 0.4 MPa in the non-dilated aorta, 0.2–0.3 MPa and 0.3–0.5 MPa in the aneurysm of the ascending aorta, and 0.1–0.2 MPa and 0.2–0.3 MPa in the aortic root aneurysm model, respectively. The loss of elasticity of the aneurysmal wall resulted in an increase of PWS by 0.1–0.2 MPa.Conclusions
Aortic geometry, wall stiffness, blood pressure and SAS have an impact on PWS. However, SAS had the biggest impact on wall stress. The results of this study may be useful in future patient-specific computational models used to assess the risk of aortic complications.992.
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Łukasz Cyganik Marcin Binkowski Grzegorz Kokot Paulina Cyganik Tomasz Rusin Filip Bolechała 《Computer methods in biomechanics and biomedical engineering》2017,20(16):1658-1668
The study presents an experimental verification of Wagner et al.’s relationship in microscale and proposes a modification of this relationship. For this purpose, 11 cubic specimens were microcomputed tomography scanned and mechanically tested with the displacement full-field measurements using a digital image correlation system. Then, numerical simulations of the compression tests were performed using a finite elements method. The Young’s modulus distributions assigned to the finite elements models were calculated using both of Wagner et al.’s relationships: original and modified. Comparison of the experimental and numerical results indicated the accuracy of numerical solutions for both relationships. 相似文献
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J. Łobarzewski A. Paszczynski T. Wolski J. Fiedurek 《Biochemical and biophysical research communications》1984,121(1):220-228
Previously solubilized feather keratin and polyamide were used for coating sand, glass beads and silica gel. These new seven supports were employed for comparative studies on pure glucoamylase / EC 3.2.1.3 / immobilization. The immobilization yield of glucoamylase on keratin and polyamide coated supports was comparable with conventional matrices used earlier. The highest activity per 1 g of support was shown by the enzyme bound to polyamide-coated CPG, and the bests operational stability by the enzyme immobilized on polyamide-coated CPG with keratin subsequently deposited on it. 相似文献
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RAFAŁOWICZ A 《Polski tygodnik lekarski (Warsaw, Poland : 1960)》1953,8(27):957-8; contd
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ŁOZA E 《Polski tygodnik lekarski (Warsaw, Poland : 1960)》1953,8(18):670-1; concl
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