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You searched for +publisher:"Clemson University" +contributor:("Ulf Schiller"). Showing records 1 – 2 of 2 total matches.

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Clemson University

1. Ghobrial, Nardine M. Using Heparin-Coated Nanoparticles in the Treatment of Neointimal Hyperplasia.

Degree: PhD, Bioengineering, 2020, Clemson University

The use of stents in the treatment of atherosclerosis leads to a potential risk of restenosis, caused by neointimal hyperplasia. Neointimal hyperplasia is mainly caused by an injury to the endothelial layer of the blood vessel followed by the proliferation of smooth muscle cells into the lumen of the blood vessel. To address this, we designed a magnetically-guided drug delivery system to locally deliver heparin to a stented artery. The nanoparticles were synthesized, characterized, and tested on relevant human cell lines. The particles were non-toxic to human smooth muscle cells, endothelial cells, and fibroblasts. They reduced the proliferation of the smooth muscle cells and increased the proliferation of endothelial cells at concentrations as low as 10 μg/mL. The particles also shifted the smooth muscle cells from their synthetic phenotype to their contractile phenotype. The capture of the nanoparticles by the stent struts, under relevant magnetic field and blood velocity was modeled using COMSOL Multiphysics. The coronary artery was modeled using a 2D axisymmetric model with stainless steel stent struts. A Magnetic field of 1 T was applied to magnetize the stent struts. Three different strut geometries were compared for their effect of the capture efficiency. The model had a capture efficiency 0f 34-42%, which is comparable to models using the same particle sizes. Ex vivo organ culture studies using porcine right coronary arteries were performed. The arteries were conditioned either statically in cell culture flasks or dynamically in an organ culture bioreactor. Nanoparticles reduced intimal thickening in and expressed contractile properties in the treated arteries compared to the controls. We were successfully able to synthesize heparin-coated magnetic nanoparticles and achieve high heparin loading. Particle capture efficiency around the stent in the ex vivo porcine artery model was found to be similar to that predicted by the computational model. Consistent with the prior results of systemic heparin delivery, the nanoparticles reduce the proliferation and dedifferentiation of vascular smooth muscle cells while promoting endothelialization, both in vitro and ex vivo. Thus, these particles may be a promising treatment option for neointimal hyperplasia. . Advisors/Committee Members: Delphine Dean, Olin T Mefford, Jeoungsoo Lee, Ulf Schiller.

Subjects/Keywords: Cardiovascular; Hemodynamics; Heparin; Magnetic; Nanoparticles

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APA (6th Edition):

Ghobrial, N. M. (2020). Using Heparin-Coated Nanoparticles in the Treatment of Neointimal Hyperplasia. (Doctoral Dissertation). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_dissertations/2674

Chicago Manual of Style (16th Edition):

Ghobrial, Nardine M. “Using Heparin-Coated Nanoparticles in the Treatment of Neointimal Hyperplasia.” 2020. Doctoral Dissertation, Clemson University. Accessed December 01, 2020. https://tigerprints.clemson.edu/all_dissertations/2674.

MLA Handbook (7th Edition):

Ghobrial, Nardine M. “Using Heparin-Coated Nanoparticles in the Treatment of Neointimal Hyperplasia.” 2020. Web. 01 Dec 2020.

Vancouver:

Ghobrial NM. Using Heparin-Coated Nanoparticles in the Treatment of Neointimal Hyperplasia. [Internet] [Doctoral dissertation]. Clemson University; 2020. [cited 2020 Dec 01]. Available from: https://tigerprints.clemson.edu/all_dissertations/2674.

Council of Science Editors:

Ghobrial NM. Using Heparin-Coated Nanoparticles in the Treatment of Neointimal Hyperplasia. [Doctoral Dissertation]. Clemson University; 2020. Available from: https://tigerprints.clemson.edu/all_dissertations/2674


Clemson University

2. Azami Ghadkolai, Milad. Engineered Porous Electrodes for High Performance Li-Ion Batteries.

Degree: PhD, School of Materials Science and Engineering, 2020, Clemson University

High specific energy/power is nearly always desirable in battery systems but it is especially important in batteries for electric vehicles. One approach for increasing the specific energy/power is to maximize the mass fraction of active materials. A straight forward approach to realize this is to make the electrodes as thick as possible. There are two main limitations for increasing electrode thickness. One is the need for active material with high electronic and ionic transport properties, and the other is rapid Li ion transport through the entire thickness of a porous electrode. In the research described in this dissertation, lithium titanite (Li4Ti5O12, LTO) was chosen as a promising safe active material for lithium batteries. In spite of many advantages, this material suffers from low electronic and ionic conductivity, making it an unsuitable choice for manufacturing thick electrodes. In order to alleviate this problem, a thorough investigation of the effect of Mo doping on structure, electronic and ionic conductivity of LTO was conducted. In order to facilitate rapid Li ion transport through the thickness of thick porous electrodes, a novel processing approach, freeze tape casting, was developed to make ordered anisotropic macro porous electrodes directly on the surface of a metal foil current collector. The effect of electrode processing parameters, microstructure and thickness on the electrochemical performance of the electrode was studied experimentally. Finally, comprehensive numerically simulations were conducted to investigate the effect of electrode microstructure (specifically thickness and tortuosity) on Li-ion transport at different discharge rate (C-rate) for both normal and freeze tape cast electrodes in order to guide the design of optimal microstructure. Computer simulations show that freeze tape cast electrodes may be fully discharged up to 750 µm thickness at 1 C rate compared to 300 µm for normal tape cast electrodes with the same mass loading. Freeze tape cast electrodes also show stable maximum areal capacity for C rates about double the maximum C rates of their normal tape cast electrode counterparts with the same mass loading. Advisors/Committee Members: Rajendra K Bordia, Stephen Creager, Kyle Brinkman, Jianhua Tong, Ulf Schiller.

Subjects/Keywords: Battery simulation; Electronic/ionic conductivity; Freeze tape casting; Li-ion battery; Lithium Titanate; Microstructure design

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

APA (6th Edition):

Azami Ghadkolai, M. (2020). Engineered Porous Electrodes for High Performance Li-Ion Batteries. (Doctoral Dissertation). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_dissertations/2623

Chicago Manual of Style (16th Edition):

Azami Ghadkolai, Milad. “Engineered Porous Electrodes for High Performance Li-Ion Batteries.” 2020. Doctoral Dissertation, Clemson University. Accessed December 01, 2020. https://tigerprints.clemson.edu/all_dissertations/2623.

MLA Handbook (7th Edition):

Azami Ghadkolai, Milad. “Engineered Porous Electrodes for High Performance Li-Ion Batteries.” 2020. Web. 01 Dec 2020.

Vancouver:

Azami Ghadkolai M. Engineered Porous Electrodes for High Performance Li-Ion Batteries. [Internet] [Doctoral dissertation]. Clemson University; 2020. [cited 2020 Dec 01]. Available from: https://tigerprints.clemson.edu/all_dissertations/2623.

Council of Science Editors:

Azami Ghadkolai M. Engineered Porous Electrodes for High Performance Li-Ion Batteries. [Doctoral Dissertation]. Clemson University; 2020. Available from: https://tigerprints.clemson.edu/all_dissertations/2623

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