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Dissertation

Mechanistic numerical study of trhombus growth

19 Apr 2007-
About: The article was published on 2007-04-19 and is currently open access. It has received 6 citations till now.

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Citations
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Journal ArticleDOI
01 Jul 1968-Nature
TL;DR: The Thermophysical Properties Research Literature Retrieval Guide as discussed by the authors was published by Y. S. Touloukian, J. K. Gerritsen and N. Y. Moore.
Abstract: Thermophysical Properties Research Literature Retrieval Guide Edited by Y. S. Touloukian, J. K. Gerritsen and N. Y. Moore Second edition, revised and expanded. Book 1: Pp. xxi + 819. Book 2: Pp.621. Book 3: Pp. ix + 1315. (New York: Plenum Press, 1967.) n.p.

1,240 citations

01 Jan 2010

6 citations


Cites background from "Mechanistic numerical study of trho..."

  • ...Alevriadou [22] Human Parallel plate, in vitro Collagen type I Fluorescent intensity...

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  • ...highest this region, reaching at least 80,000 s in canines [20-22], which is more than 2...

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01 Jan 1995
TL;DR: In this article, heat and mass transfer in the recirculation region of a pipe under steady and pulsatile conditions were studied under uniform and parabolic entrance velocity profiles and the results demonstrate the complexity of separation flows and identify characteristic regions of high and low heat/mass transfer.
Abstract: Abstract Heat and mass transfer phenomena were studied in the sudden expansion region of a pipe under steady and pulsatile conditions. The Prandtl number was varied from 100 to 12 000 and the flow was characterized for both uniform and parabolic entrance velocity profiles. A uniform velocity profile was used for pulsatile flow. It was found that heat transfer in the recirculation region was maximal near the area where wall shear was minimal. Blunting of the inlet profile caused the point of maximum heat transfer to move upstream. There was a nonlinear effect of Prandtl number on heat transfer which plateaued for Pr > 10 3 . The wall shear rate in the separation zone varied markedly with pulsatile flows, but the wall heat transfer remained relatively constant. The time-averaged pulsatile heat transfer at the wall was approximately the same as with steady flow with the mean Reynolds number. However, the isotherms within the pulsatile flow were markedly different from steady flow. The results demonstrate the complexity of separation flows and identify characteristic regions of high and low heat/mass transfer for high Prandtl/Schmidt pulsatile flow.

4 citations

Proceedings ArticleDOI
01 Jan 2016
TL;DR: In this paper, a meshless particle-based Lagrangian numerical technique, named the smoothed particles hydrodynamic (SPH) method, was used to study the flow behavior of blood and explore the flow conditions that induces the formation of thrombus in a blood vessel.
Abstract: To understand the characteristics of blood flow, it is important to identify the key parameters that influence the flow of blood. The characterisation of blood flow will also enable us to understand the flow parameters associated with physiological conditions such as atherosclerosis. Thrombosis plays a crucial role in atherosclerosis and it also helps to stop bleeding when a blood vessel is injured. This article focuses on using a meshless particle-based Lagrangian numerical technique, named the smoothed particles hydrodynamic (SPH) method, to study the flow behaviour of blood and to explore the flow conditions that induces the formation of thrombus in a blood vessel. Due to its simplicity and effectiveness, the SPH method is employed here to simulate the process of thrombogenesis for various blood flow parameters. In the present SPH simulation, blood is modelled by particles that have the characteristics of plasma and of platelets. To simulate the coagulation of platelets which forms thrombus, the adhesion and aggregation processes of the platelets are modelled by an effective inter-particle attraction force model. With these models, the motion of platelets in flowing blood, and their adhesion and aggregation are effectively coupled with viscous blood flow. In this study, the adhesion and aggregation of blood particles are analysed on a (straight vessel) under various low Reynolds number scenarios. The results are compared with the experimental results, and a good agreement is found between the simulated and experimental results.

3 citations

References
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Journal ArticleDOI
TL;DR: In this paper, two new two-equation eddy-viscosity turbulence models are presented, which combine different elements of existing models that are considered superior to their alternatives.
Abstract: Two new two-equation eddy-viscosity turbulence models will be presented. They combine different elements of existing models that are considered superior to their alternatives. The first model, referred to as the baseline (BSL) model, utilizes the original k-ω model of Wilcox in the inner region of the boundary layer and switches to the standard k-e model in the outer region and in free shear flows. It has a performance similar to the Wilcox model, but avoids that model's strong freestream sensitivity

15,459 citations


"Mechanistic numerical study of trho..." refers background or methods in this paper

  • ...One should refer to Fluent 6.2.16 documentation or (Menter 1994) for the calculation of these values....

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  • ...16 documentation or (Menter 1994) for the calculation of these values....

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  • ...The shear-stress transport (SST) k-ω model, developed by (Menter 1994), was applied in this study....

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Journal ArticleDOI
TL;DR: This paper is concerned with the mathematical structure of the immersed boundary (IB) method, which is intended for the computer simulation of fluid–structure interaction, especially in biological fluid dynamics.
Abstract: This paper is concerned with the mathematical structure of the immersed boundary (IB) method, which is intended for the computer simulation of fluid–structure interaction, especially in biological fluid dynamics. The IB formulation of such problems, derived here from the principle of least action, involves both Eulerian and Lagrangian variables, linked by the Dirac delta function. Spatial discretization of the IB equations is based on a fixed Cartesian mesh for the Eulerian variables, and a moving curvilinear mesh for the Lagrangian variables. The two types of variables are linked by interaction equations that involve a smoothed approximation to the Dirac delta function. Eulerian/Lagrangian identities govern the transfer of data from one mesh to the other. Temporal discretization is by a second-order Runge–Kutta method. Current and future research directions are pointed out, and applications of the IB method are briefly discussed. Introduction The immersed boundary (IB) method was introduced to study flow patterns around heart valves and has evolved into a generally useful method for problems of fluid–structure interaction. The IB method is both a mathematical formulation and a numerical scheme. The mathematical formulation employs a mixture of Eulerian and Lagrangian variables. These are related by interaction equations in which the Dirac delta function plays a prominent role. In the numerical scheme motivated by the IB formulation, the Eulerian variables are defined on a fixed Cartesian mesh, and the Lagrangian variables are defined on a curvilinear mesh that moves freely through the fixed Cartesian mesh without being constrained to adapt to it in any way at all.

4,164 citations


"Mechanistic numerical study of trho..." refers methods in this paper

  • ...Another method which is just recently gaining popularity is the immersed boundary method, developed by (Peskin 2002)....

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Journal ArticleDOI
TL;DR: The histological classification of human atherosclerotic lesions found in the second part of this report led to the earlier definitions of precursor lesions, and the appearance of lesions noted in clinical imaging studies with histological lesion types and corresponding clinical syndromes was attempted.
Abstract: This report is the continuation of two earlier reports that defined human arterial intima and precursors of advanced atherosclerotic lesions in humans. This report describes the characteristic components and pathogenic mechanisms of the various advanced atherosclerotic lesions. These, with the earlier definitions of precursor lesions, led to the histological classification of human atherosclerotic lesions found in the second part of this report. The Committee on Vascular Lesions also attempted to correlate the appearance of lesions noted in clinical imaging studies with histological lesion types and corresponding clinical syndromes. In the histological classification, lesions are designated by Roman numerals, which indicate the usual sequence of lesions progression. The initial (type I) lesion contains enough atherogenic lipoprotein to elicit an increase in macrophages and formation of scattered macrophage foam cells. As in subsequent lesion types, the changes are more marked in locations of arteries with adaptive intimal thickening. (Adaptive thickenings, which are present at constant locations in everyone from birth, do not obstruct the lumen and represent adaptations to local mechanical forces). Type II lesions consist primarily of layers of macrophage foam cells and lipid-laden smooth muscle cells and include lesions grossly designated as fatty streaks. Type III is the intermediate stage between type II and type IV (atheroma, a lesion that is potentially symptom-producing). In addition to the lipid-laden cells of type II, type III lesions contain scattered collections of extracellular lipid droplets and particles that disrupt the coherence of some intimal smooth muscle cells. This extracellular lipid is the immediate precursor of the larger, confluent, and more disruptive core of extracellular lipid that characterizes type IV lesions. Beginning around the fourth decade of life, lesions that usually have a lipid core may also contain thick layers of fibrous connective tissue (type V lesion) and/or fissure, hematoma, and thrombus (type VI lesion). Some type V lesions are largely calcified (type Vb), and some consist mainly of fibrous connective tissue and little or no accumulated lipid or calcium (type Vc).

3,698 citations

Journal ArticleDOI
03 May 1984-Nature
TL;DR: The ability of fibronectin to bind cells can be accounted for by the tetrapeptide L-arginyl-glycyl- L-aspartyl-L-serine, a sequence which is part of the cell attachment domain of fibronsectin and present in at least five other proteins.
Abstract: The ability of fibronectin to bind cells can be accounted for by the tetrapeptide L-arginyl-glycyl-L-aspartyl-L-serine, a sequence which is part of the cell attachment domain of fibronectin and present in at least five other proteins. This tetrapeptide may constitute a cellular recognition determinant common to several proteins.

3,574 citations


"Mechanistic numerical study of trho..." refers background in this paper

  • ...Also, an integrin recognition sequence for VWF has been found in fibrinogen, laminin, and collagen (Pierschbacher and Ruoslahti 1984; Pierschbacher and Ruoslahti 1987)....

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Journal ArticleDOI
TL;DR: In this article, it was shown that a sphere moving through a very viscous liquid with velocity V relative to a uniform simple shear, the translation velocity being parallel to the streamlines and measured relative to streamline through the centre, experiences a lift force 81·2μVa2k½/v½ + smaller terms perpendicular to the flow direction, which acts to deflect the particle towards the streamline moving in the direction opposite to V.
Abstract: It is shown that a sphere moving through a very viscous liquid with velocity V relative to a uniform simple shear, the translation velocity being parallel to the streamlines and measured relative to the streamline through the centre, experiences a lift force 81·2μVa2k½/v½ + smaller terms perpendicular to the flow direction, which acts to deflect the particle towards the streamlines moving in the direction opposite to V. Here, a denotes the radius of the sphere, κ the magnitude of the velocity gradient, and μ and v the viscosity and kinematic viscosity, respectively. The relevance of the result to the observations by Segree & Silberberg (1962) of small spheres in Poiseuille flow is discussed briefly. Comments are also made about the problem of a sphere in a parabolic velocity profile and the functional dependence of the lift upon the parameters is obtained.

2,912 citations


"Mechanistic numerical study of trho..." refers background in this paper

  • ...The term Fx includes any additional forces applied to a particle, such as the Saffman lift force (Saffman 1965)....

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  • ...In contrast with RBCs, rigid spheres and discs tend to also migrate away from the central axis, which has been attributed to inertial forces in the fluid, specifically, lift forces (Saffman 1965) for neutrally buoyant particles....

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  • ...Equation 19: Force balance on a particle ( ), ,i p D i i p x u F u u F t ∂ = − + ∂ The term Fx includes any additional forces applied to a particle, such as the Saffman lift force (Saffman 1965)....

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  • ...axis, which has been attributed to inertial forces in the fluid, specifically, lift forces (Saffman 1965) for neutrally buoyant particles....

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