Barrett, The Honors College Thesis/Creative Project Collection
Barrett, The Honors College at Arizona State University proudly showcases the work of undergraduate honors students by sharing this collection exclusively with the ASU community.
Barrett accepts high performing, academically engaged undergraduate students and works with them in collaboration with all of the other academic units at Arizona State University. All Barrett students complete a thesis or creative project which is an opportunity to explore an intellectual interest and produce an original piece of scholarly research. The thesis or creative project is supervised and defended in front of a faculty committee. Students are able to engage with professors who are nationally recognized in their fields and committed to working with honors students. Completing a Barrett thesis or creative project is an opportunity for undergraduate honors students to contribute to the ASU academic community in a meaningful way.
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Description
Intracranial aneurysms are blood \u2014filled sacs along the blood vessels in the brain. These aneurysms can be particularly dangerous due to difficulty in detection and potential lifethreatening outcome. When these aneurysms are detected, there are few treatment options to prevent rupture, one of which is endovascular stents. By placing a stent across the parent vessel, blood flow can be diverted from the aneurysm. Reduced flow reduces the chance of rupture and promotes clotting within the aneurysm. In this study, hemodynamics in idealized basilar tip aneurysm models were investigated at three flow rates using particle imaging velocimetry (PIV). Two models were created with increasing dome size (4mm vs 6mm), and constant dome-to-neck ratio (3:2) and parent vessel contact angle to represent growing aneurysm. With the pulsatile flow, data is acquired at three separate points in the cardiac cycle. Both of the models were studied untreated, treated with Enterprise stent and treated with Pipeline stent. Enterprise stent was developed mainly for structural support while the Pipeline stent was developed as a flow diverter. Due to target functions of the stents, Enterprise stent is more porous than the Pipeline stent. Hemodynamics were studied using a stereo particle image velocimetry technique. The flow in models was characterized by neck and aneurysmal RMS velocity, neck and aneurysm kinetic energy, cross neck flow. It was found that both of the stents are capable diverting flow. Enterprise reduced aneurysmal RMS velocity in model 1 by 38.7% and in model 2 by 76.2%. Pipeline stent reduced aneurysmal RMS velocity in model 1 by 71.4% and in model 2 by 88.1%. Both reductions are data for 3ml/s at peak systole pulsatile flow. Data shows that the Pipeline stent is better than Enterprise stent at reducing flow to the aneurysm.
ContributorsChung, Hanseung (Author) / Frakes, David (Thesis director) / Caplan, Michael (Committee member) / Babiker, Haithem (Committee member) / Barrett, The Honors College (Contributor) / Economics Program in CLAS (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05
Description
Traumatic brain injury (TBI) is a leading cause of injury related death in the United States. The complexity of the injury environment that follows TBI creates an incomplete understanding of all the mechanisms in place to regulate chemotactic responses to TBI. The goal of this project was to develop a predictive in silco model using diffusion and autocrine/paracrine signaling specific to stromal cell derived factor-1α (SDF-1α) gradient formation after TBI and compare this model with in vivo experimental data. A COMSOL model using Fickian diffusion and autocrine/paracrine reaction terms was generated to predict the gradient formation observed in vivo at three physiologically relevant time points (1, 3, and 7 days). In vivo data was gathered and analyzed via immunohistochemistry and MATLAB. The spatial distribution of SDF-1α concentration in vivo more consistently demonstrated patterns similar to the in silico model dependent on both diffusion and autocrine/paracrine reaction terms rather than diffusion alone. The temporal distribution of these same results demonstrated degradation of SDF-1α at too rapid a rate, compared to the in vivo results. To account for differences in behavior observed in vivo, reaction terms and constants of 1st-order reaction rates must be modulated to better reflect the results observed in vivo. These results from both the in silico model and in vivo data support the hypothesis that SDF-1α gradient formation after TBI depends on more than diffusion alone. Future work will focus on improving the model with constants that are specific to SDF-1α as well as testing methods to better control the degradation of SDF-1α.
ContributorsFreeman, Sabrina Louise (Author) / Stabenfeldt, Sarah (Thesis director) / Caplan, Michael (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05