MASS TRANSPORT WITH MIXED BOUNDARY CONDITIONS WITH SPECIAL APPLICATION TO PROBLEMS IN ATHEROGENESIS (CHOLESTEROL).
Item
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Title
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MASS TRANSPORT WITH MIXED BOUNDARY CONDITIONS WITH SPECIAL APPLICATION TO PROBLEMS IN ATHEROGENESIS (CHOLESTEROL).
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Identifier
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AAI8409425
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identifier
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8409425
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Creator
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TZEGHAI, GHEBRE E.
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Contributor
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Robert Pfeffer | Sheldon Weinbaum, Peter Ganatos
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Date
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1984
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Language
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English
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Publisher
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City University of New York.
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Subject
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Engineering, Biomedical
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Abstract
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This thesis deals with the construction of new theoretical models to help elucidate and quantify the fundamental mechanisms by which cholesterol carrying and related macromolecules first cross the arterial endothelium and subsequently diffuse into the underlying tissue. Atherosclerosis, an arterial disease which is recognized as the leading cause of death in most developed countries is associated with the accumulation of these macromolecules in the arterial wall.;Thus far, the existing large body of experimental and theoretical findings strongly suggest that the mechanisms which govern transport of macromolecules across arterial wall are strongly dependent on the structural integrity of the arterial endothelium. The theoretical work presented herein offers some explanations to these findings.;The predictions from the first model show that the endothelium is the major resistance to transarterial transport of macromolecules greater than 40(ANGSTROM) and that only a small fraction of the endothelial junctions need be disrupted to produce a significant change in the concentration distribution of macromolecules in the wall. An extension of this model shows that convection will produce about a 20% increase in flux of macromolecules into the wall for small endothelial damage (< 1%), but that the effect of convection will increase dramatically as the damage size or the number of leaky junctions increases.;For the first time, (1) the coupling of the endothelial junction resistance with that of the media has been examined quantitatively so that the rate of water filtration and the pressure distribution in the arterial wall can be estimated. From this model it is found that when the tight junction width is 26(ANGSTROM), more than half of the transmural pressure drop can be sustained by the endothelium for a wall whose media thickness is less than 200(mu)m, and (2) the arterial distribution volume has been quantified. The latter results clearly show that the artery wall consists essentially of two distinct regions of relatively constant diffusion coefficient, the media and the adventitia with an abrupt change in diffusion coefficient occurring at their interface. Furthermore, it is indicated that the distribution volume is larger in the adventitia than in the media.;All of the findings indicated above are in a very favorable agreement with experimental physiological data.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
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Program
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Engineering
