PHD, Kent State University, 2021, College of Public Health

Title: Transjugular Intrahepatic Portosystemic Shunt (TIPS), Duration of Procedural Time and Correlation with Early Morbidity and Mortality Author: Juan Carlos Barrera Gutierrez, PhD., Candidate in Epidemiology ABSTRACT Purpose: 1. To examine the relationship between patient factors (demographics or clinical) and duration of TIPS procedure. 2. To determine if duration of TIPS procedure is associated with early morbidity, including acute kidney injury, liver dysfunction, and intraoperative or postoperative bleeding. 3. Determine if duration of TIPS procedure is related to early mortality (or operative mortality). Materials and Methods: Data for this retrospective study was abstracted using the REDcap system from patients' electronic records. Inclusion criteria were patients over 18 years of age who underwent an initial TIPS procedure (for any indication) between January 2005 and August 2020. Exclusion criteria were those TIPS performed out of the institution and failed TIPS procedures. Regression analysis was used to identify the predictors of procedural time, the predictors of morbidity and mortality. Results: The mean age at TIPS procedure was 57 years. Most patients (70%) were male, and Non-Hispanic whites made up the largest group (80.5%). The main predictor of procedural time was baseline bilirubin (beta coefficient: 4.9 minutes, p = 0.005) in those patients that did not require extra access. Additionally etiology of cirrhosis and staff experience were predictors of procedural time. The main predictor of acute kidney injury (AKI) immediately after TIPS were gender (p = 0.02) and body mass index (BMI) (p = 0.04). MELD score (p = 0.02), age (p = 0.003), gender (p = 0.001), and time (p = 0.01) became the best predictors of liver function post TIPS in those patients with ascites and who did not require extra access. The mortality rate in the first month after TIPS was 14.5%, and the predictors associate to this were MELD score (OR: 1.17, p=0.004 (open full item for complete abstract)

Committee: Melissa Zullo (Committee Chair); Lynette Phillips (Committee Member); Jonathan VanGeest (Committee Member); Sidhartha Tavri (Advisor) Subjects: Epidemiology; Health; Health Care; Health Sciences; Medicine; Public Health; Radiology

Master of Science, The Ohio State University, 2020, Aero/Astro Engineering

The purpose of this work was to investigate the low-speed aerodynamic characteristics of a novel delta wing layout with deflected wing tips. This project is motivated by the ongoing unmanned aerial vehicle research and development at The Ohio State University Aerospace Research Center. The model under test for this study had four main design requirements: (1) high-speed, (2) highly maneuverable, (3) aerodynamically interesting, and (4) multi-configurable. The last three requirements are addressed directly in this report with specific emphasis on requirements two and three. A modular fuselage design satisfied requirement four, and the novel delta wing addressed requirements two and three. The novel delta wing has a leading-edge sweep of 60 degrees, a high-speed airfoil with a rounded leading-edge, and wing tips that can rotate a full 180 degrees about a hinge, located at 2/3rds of the half-span parallel to fuselage centerline. Three different wing tip deflection configurations were analyzed: positive, negative, and asymmetric. Positive wing tip deflection corresponds to the wing tips being deflected up towards the vertical tail. Negative wing tip deflection is when the wing tips are deflected down, away from the vertical tail. While the asymmetric configuration has one wing tip deflected up and the other down. Analysis on the model was completed using a panel method code and experimental wind tunnel testing. The panel method code used was OpenVSP. Upon implementing a vortex lift factor, it was determined that the delta wing results from OpenVSP were only useful for lift related data after comparing the panel method results to theory and publicly available delta wing data. The wind tunnel used for this work is located at the Aerospace Research Center. The wind tunnel is an open circuit subsonic wind tunnel with a 3'x5' test section. Aerodynamic forces were measured using an internal six-component force balance. Tests were performed at two different Reynolds numb (open full item for complete abstract)

Committee: Clifford Whitfield Dr. (Advisor); Rick Freuler Dr. (Committee Member); Matthew McCrink Dr. (Committee Member) Subjects: Aerospace Engineering

Master of Science (MS), Wright State University, 2013, Chemistry

The synthesis of the arylnaphthalene lignan haplomyrtin using vanillin as a starting material is synthesized via: 1) a bromination of vanillin, 4-hydroxy-5-methoxybenzaldehyde, to produce 6-bromovanillin 2) a hydroxyl protection step of 6-bromovanillin with triisopropylsilylchloride to produce 2-bromo-4-triisopropylsilyoxy-5-methoxybenzaldehyde 3) an aldehyde protection step through a cyclic acetal formation using ethylene glycol to produce 2-(2-bromo-4-triisopropylsilyloxy-5-methoxyphenyl)-1,3-dioxolane 4) a lithium for halogen exchange of the doubly protected 6-bromovanillin leads to neucleophilic coupling with piperonal producing 1,3-benzodioxol-5-yl-[5-triisopropylsilyloxy-2-(1,3-dioxolane-2-yl)-4-methoxyphenyl]methanol and 5) an acid catalyzed intramolecular cycloaddition /Diels Alder adduct with dimethyl acetylenedicarboxylate producing dimethyl 1-(1,3-benzodioxol-5-yl)-4-hydroxy-6-methoxy-7-triisopropylsilyloxynaphthalene-2,3-dicarboxylate.

Committee: William Feld Ph.D. (Advisor); Daniel Ketcha Ph.D. (Committee Member); Kenneth Turnbull Ph.D. (Committee Member) Subjects: Chemistry; Organic Chemistry

Doctor of Philosophy, The Ohio State University, 2010, Chemical and Biomolecular Engineering

The nanoporous PCL membranes were prepared via the combination of thermally- and nonsolvent-induced phase separations. For the phase separation process, nonsolvent has significant effect on pore formation and drug release rate. In nonsolvent-induced phase separation, a large amount of nonsolvent was added to casting solutions in order to improve pore connectivity within the membrane. The use of a Teflon plate for membrane casting can result in uniform nanoporous membranes and consistent lysozyme diffusion. Pore connectivity was improved significantly when coagulation bath temperature was lowered. By using a 5°C water coagulation bath in the wet-process precipitation, the average pore size reduced from 90 nm to 55 nm while increasing the casting solution concentration from 15 wt% to 25 wt% PCL. Thus, by varying the polymer concentration of the casting solution, the lysozyme release rate can be manipulated with precise control. The potential application of nanoporous PCL membranes to achieve the preferable zero-order release rate is demonstrated in this dissertation. Along with achieving the zero-order release rate, the nanoporous PCL membranes also provide immunoprotection for cell-based therapies/devices. Immunoisolation can be achieved by preventing Immunoglobulin G (IgG) from diffusing through the nanoporous PCL membranes. With appropriate pore size, the nanoporous PCL membranes can allow the diffusion of therapeutic agents (lysozyme) and block the diffusion of immune molecules (IgG). The application of the nanoporous PCL membranes to cell-based therapies/devices is also demonstrated in this dissertation. Extensive fibrosis induced by the healing process can be detrimental to the long-term performance of implantable applications. The prevention of fibroblast adhesion to the nanoporous PCL membrane surface is crucial for constant and well controlled drug release. This study shows a novel method to modify the nanoporous PCL membrane surface with poly(ethylene glyco (open full item for complete abstract)

Committee: W.S. Winston Ho (Advisor); Boyaka Prosper N. (Committee Member); Koelling Kurt W. (Committee Member); Lee L. James (Committee Member) Subjects: Biomedical Research; Chemical Engineering; Engineering; Polymers

Master of Science in Engineering, University of Akron, 2009, Mechanical Engineering

The scratch behaviors of a set of model polymers [polystyrene (PS)] with different molecular weights are investigated to understand how the material characteristics of the polymer material affect the scratch resistance at a fundamental level. In this work, both tensile and scratch tests were conducted to examine the tensile and surface mechanical properties of the PS. The scratch tests were carried out using both the conical and Berkovich tips and were found that the conical tip exhibits greater surface damage than the Berkovich tip. It was also observed that there was no strong correlation between the measured tensile and scratch properties. The SEM images from the scratch experiment using conical indenter indicate that the PSC with high molecular weight exhibits less surface damage than the other two samples with low molecular weights. The FE modeling of this scratch process using conical indenter has been performed for all the three PS samples and has been shown that PSC, with higher molecular weight exhibits less surface damage when compared to the other two samples with low molecular weights.

Committee: Shing-Chung 'Josh' Wong PhD (Advisor) Subjects: Mechanical Engineering

Doctor of Philosophy, University of Akron, 2006, Polymer Science

Material behavior on “nano” length scales deviates significantly from the bulk and understanding this behavior is vital for the progress of nanotechnology. Scanning probe microscope (SPM) and its modifications have been used for simultaneous topographical and mechanical, electrical, magnetic or thermal characterization with nanoscale resolution. However, techniques for nanoscale chemical analysis are still under development. Tip enhanced Raman spectroscopy (TERS), the combination of an apertureless near-field optical microscope with a Raman spectrometer, is a promising technique for analyzing the chemical composition, structure and conformational states on the nanoscale. This technique is based on the excitation of plasmons on a metallic tip which gives gigantic localized enhancement of the Raman signal. However, its widespread application requires optimization of the technique to achieve reproducibly high enhancements. This thesis focuses on the development and optimization of scanning nano-Raman spectroscopy (SNRS) – a TERS technique based on side illumination optics. Reproducible enhancements of the Raman signal using both silver- and gold-coated silicon nitride tips have been observed on various samples that include semiconducting, molecular and polymeric systems and single walled carbon nanotubes. Localization of the enhancement under the tip has been estimated to be ~20 nm. Reasonable enhancement factors of ~103 – 104 have been attained with almost every tip. We have ascertained that contrast (defined as the ratio of the near-field signal to the far-field signal), not the tip enhancement factor, is the key parameter in comprehending the applicability of TERS for nanoscale imaging. For thick samples, contrast is limited by a strong far-field signal that overpowers the near-field signal. Hence, one approach to increasing contrast is by suppressing the far-field signal. We demonstrate that optimization of the incident beam angle and polarization to reduce the (open full item for complete abstract)

Committee: Alexei Sokolov (Advisor) Subjects: Physics, Optics