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You searched for +publisher:"Virginia Tech" +contributor:("Chappell, John C."). Showing records 1 – 2 of 2 total matches.

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Virginia Tech

1. Darden, Jordan Alexandra. Pericytes in Early Vascular Development.

Degree: PhD, Translational Biology, Medicine and Health, 2019, Virginia Tech

Blood vessels have the crucial job of delivering oxygen and nutrients to all the cells in the body. To perform this duty, blood vessels- and the components that make them- must develop and mature into a healthy network, capable of altering itself to meet new needs of the body. The early programs that “push” the vessel system to develop are the same programs that reactivate when there are normal changes to the body such as injury, muscle growth or decline, or aging; and when abnormal diseases arise like cancer, stroke, and diabetes. Therefore, it is critical to understand how blood vessels develop into healthy systems by studying all of their components as they mature. Endothelial cells that comprise the vessels themselves are joined by specialized partner cells called pericytes that help guide and mature vessel growth. Pericytes lie elongated along endothelial cells and have multiple points of contact with the endothelium. In this position, pericytes assist in cell-cell communication and even blood flow regulation in smaller vessels called capillaries. To study the relationship between endothelial cells and pericytes during development, we observed vascular anatomy in three and four dimensions, as well as mechanisms underlying how these cells come together and interact in several experimental models. Thus, to thoroughly analyze the morphology of these vessels, we developed a rigorous methodology using a MATLAB program to determine the colocalization and coverage of pericytes associated with vessels in large image sets. After developing analytical method to investigate all the components of the blood vessel wall, we expanded our investigation of how pericytes and other aspects of blood vessels develop in animal models, specifically a more commonly used animal model for vascular development and for treatment of human diseases. Our findings of vascular development in mice suggest that there are important differences in how human and mouse brain blood vessels form. Therefore, studies using mice must be carefully designed to account for these discrepancies. Additionally, research into why human and mouse neurovascular development and maturation are different can aid in the development of improved experimental models to better treat human illness and injury. Advisors/Committee Members: Chappell, John C. (committeechair), McDonald, Sarah (committee member), Gourdie, Robert (committee member), Sontheimer, Harald (committee member).

Subjects/Keywords: pericyte recruitment; vascular development; periyte-endothelial cell interactions; developmental pathogenesis

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APA (6th Edition):

Darden, J. A. (2019). Pericytes in Early Vascular Development. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/89057

Chicago Manual of Style (16th Edition):

Darden, Jordan Alexandra. “Pericytes in Early Vascular Development.” 2019. Doctoral Dissertation, Virginia Tech. Accessed July 07, 2020. http://hdl.handle.net/10919/89057.

MLA Handbook (7th Edition):

Darden, Jordan Alexandra. “Pericytes in Early Vascular Development.” 2019. Web. 07 Jul 2020.

Vancouver:

Darden JA. Pericytes in Early Vascular Development. [Internet] [Doctoral dissertation]. Virginia Tech; 2019. [cited 2020 Jul 07]. Available from: http://hdl.handle.net/10919/89057.

Council of Science Editors:

Darden JA. Pericytes in Early Vascular Development. [Doctoral Dissertation]. Virginia Tech; 2019. Available from: http://hdl.handle.net/10919/89057


Virginia Tech

2. Hosseinzadegan, Hamid. A Physio-chemical Predictive Model of Dynamic Thrombus Formation and Growth in Stenosed Vessels.

Degree: PhD, Mechanical Engineering, 2017, Virginia Tech

According to the World Health Organization (WHO), Cardiovascular Disease (CVD) is the leading cause of death in the world. Biomechanics and fluid dynamics of blood flow play an important role in CVD mediation. Shear stress plays a major role in platelet-substrate interactions and thrombus formation and growth in blood flow, where under both pathological and physiological conditions platelet adhesion and accumulation occur. In this study, a three-dimensional dynamic model of platelet-rich thrombus growth in stenosed vessels using computational fluid dynamics (CFD) methods is introduced. Platelet adhesion, aggregation and activation kinetics are modeled by solving mass transport equations for blood components involved in thrombosis. The model was first verified under three different shear conditions and at two heparin levels. Three-dimensional simulations were then carried out to evaluate the performance of the model for severely damaged (stripped) aortas with mild and severe stenosis degrees. For these cases, linear shear-dependent functions were developed for platelet-surface and platelet-platelet adhesion rates. It was confirmed that the platelet adhesion rate is not only a function of Reynolds number (or wall shear rate) but also the stenosis severity of the vessel. General correlations for adhesion rates of platelets as functions of stenosis and Reynolds number were obtained based on these cases. The model was applied to different experimental systems and shown to agree well with measured platelet deposition. Then, the Arbitrary Lagrangian Eulerian (ALE) formulation was used to model dynamic growth by including geometry change in the simulation procedure. The wall boundaries were discretely moved based on the amount of platelet deposition that occurs on the vessel wall. To emulate the dynamic behavior of platelet adhesion kinetics during thrombus growth, the validated model for platelet adhesion, which calculates platelet-surface adhesion rates as a function of stenosis severity and Reynolds number, was applied to the model. The model successfully predicts the nonlinear growth of thrombi in the stenosed area. These simulations provide a useful guide to understand the effect of growing thrombus on platelet deposition rate, platelet activation kinetics and occurrence of thromboembolism (TE) in highly stenosed arteries. Advisors/Committee Members: Tafti, Danesh K (committeechair), Qiao, Rui (committee member), Staples, Anne E (committee member), Behkam, Bahareh (committee member), Chappell, John C. (committee member), Grant, John W (committee member).

Subjects/Keywords: Numerical modeling; Atherosclerosis; Platelet adhesion; Platelet activation; Embolism

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Hosseinzadegan, H. (2017). A Physio-chemical Predictive Model of Dynamic Thrombus Formation and Growth in Stenosed Vessels. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/89325

Chicago Manual of Style (16th Edition):

Hosseinzadegan, Hamid. “A Physio-chemical Predictive Model of Dynamic Thrombus Formation and Growth in Stenosed Vessels.” 2017. Doctoral Dissertation, Virginia Tech. Accessed July 07, 2020. http://hdl.handle.net/10919/89325.

MLA Handbook (7th Edition):

Hosseinzadegan, Hamid. “A Physio-chemical Predictive Model of Dynamic Thrombus Formation and Growth in Stenosed Vessels.” 2017. Web. 07 Jul 2020.

Vancouver:

Hosseinzadegan H. A Physio-chemical Predictive Model of Dynamic Thrombus Formation and Growth in Stenosed Vessels. [Internet] [Doctoral dissertation]. Virginia Tech; 2017. [cited 2020 Jul 07]. Available from: http://hdl.handle.net/10919/89325.

Council of Science Editors:

Hosseinzadegan H. A Physio-chemical Predictive Model of Dynamic Thrombus Formation and Growth in Stenosed Vessels. [Doctoral Dissertation]. Virginia Tech; 2017. Available from: http://hdl.handle.net/10919/89325

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