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2005
Atherosclerotic lesions may occur in arteries where there are major changes in flow patterns, e.g. bifurcations and junctions. As in an arterial stenosis, disturbed flows in such areas may affect the transport of atherogenic macromolecules and lipids from flowing blood to the luminal surface. The altered transfer of these substances at the junctions, in turn, might result in enhanced lipid infiltration, leading to atherosclerotic lesions. To predict the possible locations of atherogenesis, we used a two-dimensional bifurcation as a human carotid bifurcation model to simulate theoretically the blood flow and to assess quantitatively the effect of a disturbed flow on the luminal surface lipid concentration at the blood/vessel wall interface. The results show that disturbed flows at arterial bifurcations and surgically created junctions enhance atherogenic substance and lipid transfer from flowing blood toward vessel walls. Therefore, these areas have the potential of developing athero...
Journal of The Royal Society Interface
Modelling and simulation of low-density lipoprotein transport through multi-layered wall of an anatomically realistic carotid artery bifurcation2013 •
A high concentration of low-density lipoprotein (LDL) is recognized as one of the principal risk factors for development of atherosclerosis. This paper reports on modelling and simulations of the coupled mass (LDL concentration) and momentum transport through the arterial lumen and the multi-layered arterial wall of an anatomically realistic carotid bifurcation. The mathematical model includes equations for conservation of mass, momentum and concentration, which take into account a porous layer structure, the biological membranes and reactive source/sink terms in different layers of the arterial wall, as proposed in Yang & Vafai (2006). A four-layer wall model of an arterial wall with constant thickness is introduced and initially tested on a simple cylinder geometry where realistic layer properties are specified. Comparative assessment with previously published results demonstrated proper implementation of the mathematical model. Excellent agreement for the velocity and LDL concent...
2011 •
Journal of biological physics
Steady flow visualization in a rigid model of the aortic bifurcation: application to atherosclerosis2001 •
Hemodynamics have long been implicated in atherogenesis. The studiesreported here seek to explain the mechanisms for the formation ofatherosclerotic plaque in an aortic bifurcation. Flow studies were made ina model constructed from plexiglass to represent an aortic bifurcation. Under steady flow conditions at inflow Reynolds numbers of 80-1250,the streamline flow patterns and the boundary layer separation zones wereinvestigated in relation to the location of atherosclerotic plaques clinicallyfound at regions in the human aortic bifurcation. The streamline flowswere visualized by a slow injection of dye over the cross section of the tubeentrance and along the tube walls. The studies revealed a complex flowfield where secondary flows, induced by the centrifugal and viscous forces,cause the fluid to move towards the inner walls of the aortic bifurcation. The effect was more clearly seen with increasing Reynolds number. Boundary layer separation zones were observed to occur at the outer...
Computer Methods in Applied Mechanics and Engineering
Growth model for cholesterol accumulation in the wall of a simplified 3D geometry of the carotid bifurcation2011 •
Atherosclerosis is one of the leading causes of death in the first world countries nowadays. It is a vascular disease that affects medium and large size arteries, involving the formation of plaques within the artery wall. These plaques result from the accumulation of fat, cholesterol, cell debris, smooth muscle cells and other cells and substances, and may cause temporary or definitive lack of blood supply to an organ.This article proposes a model for cholesterol accumulation and plaque growth. The model is basically a mass balance of low density lipoproteins (LDL) in the intima. The inflow, outflow, oxidation, and consumption of LDL is modeled combining partial models and correlations available in the literature.The model was implemented into an open source finite volume code. Assuming steady blood flow, the code was used to predict lesion formation on a three-dimensional model of the carotid artery bifurcation, a location greatly studied for its role in supplying blood to some parts of the brain and for being related to strokes due to formation of atheromas. The simulation was carried out under physiologic conditions for blood pressure and LDL blood concentration.Results for LDL mass accumulation and intimal thickening over time, plaque shape, and location of thicker spots are reported, showing that the proposed model approximates reasonably well the intimal thickening obtained from post-mortem aortic fatty streaks and from B-mode ultrasonography of the carotid artery of healthy subjects reported by other authors.►We model the cholesterol accumulation in the early stages of an atherosclerotic lesion. ► We model the link between the cholesterol accumulation and the intimal thickening. ► We tested the model in a simplified 3D geometry of carotid bifurcation. ► We find good agreement between the model and in vivo wall thickening measured by others. ► Intimal thickening is predicted to grow linearly on average and non-linearly on focal spots.
2009 •
Biomechanics and Modeling in Mechanobiology
Hemodynamics and wall mechanics in human carotid bifurcation and its consequences for atherogenesis: investigation of inter-individual variation2004 •
Vojnosanitetski pregled
Atherosclerosis and coronary artery bifurcation lesions: Anatomy and flow characteristics2015 •
EuroIntervention
Impact of local flow haemodynamics on atherosclerosis in coronary artery bifurcations2015 •
Scientific reports
Determination of hemodynamic risk for vascular disease in planar artery bifurcations2018 •
Understanding hemodynamics in blood circulation is crucial in order to unveil the mechanisms underlying the formation of stenosis and atherosclerosis. In fact, there are experimental evidences pointing out to the existence of some given vessel configurations that are more likely to develop the above mentioned pathologies. Along this manuscript, we performed an exhaustive investigation in a simplified model aiming to characterize by means of physical quantities those regions and configurations in vessel bifurcations that are more likely to develop such pathologies. The two-fold analysis is based, on the one hand, on numerical simulations (via CFD) and, on the other hand, on experiments realized in an ad-hoc designed polydimethylsiloxane (PDMS) channel with the appropriate parameters and appropriate fluid flows. The results obtained demonstrate that low velocity regions and low shear stress zones are located in the outer walls of bifurcations. In fact, we found that there is a critica...
The Routledge Handbook of Heritage Destruction
Iraqi and Syrian Responses to Heritage Destruction under the Islamic State: Genocide, Displacement, Reconstruction, and Return2024 •
Basrah journal for engineering science
Thermo-Economic Analysis of Simple Cycle Steam Power Plant2022 •
2023 •
J-CEKI : Jurnal Cendekia Ilmiah
Teori Limit Muhammad Syahrur Dalam Studi IslamDIRITTO & QUESTIONI PUBBLICHE
“Un libro che non ha mai finito di dire quello che ha da dire”. La Costituente di Costantino Mortati2022 •
The EMBO Journal
Ly-6A is required for T cell receptor expression and protein tyrosine kinase fyn activity1994 •
Cellulose
Holistic solution to natural fiber deterioration in cement composite using hybrid treatments2019 •
2018 •
İzmir Dr.Behçet Uz çocuk hastanesi dergisi
Respiratory Viruses in Pediatric Patients with Suspected COVID-19 at the Early Stages of the Pandemic: A Single-center Experience2022 •
Seminars in Neurology
Neurorehabilitation of Lightning and Electrical Injuries1995 •
Journal of Photochemistry and Photobiology B: Biology
Photodynamic therapy of HeLa cell cultures by using LED or laser sources2016 •