Masters of Science in Kinesiology and Health, Miami University, 2023, Kinesiology, Nutrition, and Health

Riding an electric bike (EB) is a form of light to moderate-intensity aerobic physical activity (PA). Regular aerobic PA decreases central arterial stiffness and plasma endothelin-1 (ET-1), contributing to reduced cardiovascular disease risk. PURPOSE: To determine the effects of riding an EB for one week on central arterial stiffness and plasma ET-1. METHODS: Twelve healthy and recreationally active adults [49 ± 13 y; BMI = 26.3 ± 5.7 kg/m2] were monitored for one week without an EB (no EB) and one week with an EB. Participants were instructed to ride the EB a minimum of 4 d/wk for 30 min/d. An accelerometer tracked PA continuously for 14 days. Blood pressure, carotid-femoral pulse wave velocity (cf-PWV), and plasma ET-1 were measured at day 1 and day 14. One-way repeated measures ANOVA was performed to compare data between trials and Pearson correlations determined associations among study variables. RESULTS: Resting blood pressure and plasma ET-1 were unchanged, whereas cf-PWV decreased by 6.1% (p = 0.04) with EB use. No significant associations were discovered between PA, plasma ET-1, and cf-PWV. CONCLUSION: Our findings show that riding an EB for 1 week decreased central arterial stiffness in healthy adults.

Committee: Kevin Ballard (Committee Chair); Kyle Timmerman (Committee Member); Helaine Alessio (Committee Member) Subjects: Kinesiology

Bachelor of Science, Wittenberg University, 2022, Exercise Science

While majority of the evidence shows acute and longitudinal cardiovascular anomalies exist in a patient population following COVID-19 infection, little is known about subsequent cardiovascular effects in a student-athlete population. With known potential effects to student-athletes pulmonary function, it is reasonable to assume long-term cardiovascular complications exist as well. Therefore, the aim of this study is to determine if longitudinal cardiovascular effects of COVID-19 exist in student-athletes. Twenty-four college-aged student-athletes were split into two groups for comparison based on self-reported COVID status. Twelve subjects reported to have tested positive for COVID-19 10-14 months prior (COV+), while the other twelve participants reported to have never tested positive for COVID-19 (CON). Both groups were sport-matched to ensure that cardiorespiratory fitness was comparable. Direct comparison of both groups was analyzed for VO2, heart rate, and blood pressure via student t-tests with significance set a priori at p<0.05. Age, resting heart rate, resting mean arterial pressure, VO2peak were not different between groups. Additionally, heart rate and mean arterial pressure during exercise corresponding to 85% HRR was not different between groups. Heart rate recovery and mean arterial pressure recovery after exercise was different between groups, with a longer recovery period for the COV+ group compared to the CON group. The mean arterial pressure recovery time is prolonged before returning to resting levels in the representative subject from the COV+ group. Additionally, heart rate was slowed in returning to resting levels in the COV+ group. Interestingly, no differences existed between groups regarding heart rate and mean arterial pressure during exercise.

Committee: John Thistlethwaite (Advisor); Cathy Pederson (Committee Member); Hung-Sheng Hsu (Committee Member) Subjects: Health Care; Health Sciences; Sports Medicine

MS, University of Cincinnati, 2020, Allied Health Sciences: Nutrition

Background: Excessive intake of dietary Advanced Glycation End Products (dAGEs) or conditions that accelerate endogenous AGE formation, such as hyperglycemia, can promote oxidative stress and inflammation by cross-linking with body proteins and altering their structure and function. Several small-scale studies suggest an association between AGEs and inflammation and vascular dysfunction in individuals with diabetes, however, these relationships have not been examined in a large, diverse sample of youth with type 1 diabetes (T1D). Purpose: To determine the association between dAGEs and markers of inflammation and arterial stiffness in a diverse sample of youth with T1D from the multi-center SEARCH for Diabetes in Youth study. Methods: Children and adolescents from the SEARCH for Diabetes in Youth Study, ages 10-19 years, with T1D who had completed a demographics and food frequency questionnaire (FFQ) had measures of inflammation (IL-6, C-reactive protein, fibrinogen) and arterial stiffness. Measures of arterial stiffness included pulse wave velocity from carotid to the femoral artery (PWVcf), from the carotid to the radial artery (PWVcr) and from the femoral artery to the foot (PWVfft). Dietary AGE intake was determined by matching AGE values in foods reported by Uribarri et al. (1) to the FFQ foods and calculating daily AGE in kU/day. Clinical measures included BMI z-score, HbA1c at visit, systolic and diastolic blood pressure, mean arterial blood pressure, heart rate, and lipid profile. Associations between dAGE, inflammation and arterial stiffness measures were determined by multiple regression analysis adjusting for demographic and clinical measures. Results: From our sample of 1,623 TID youth, average dAGE intake was 17,704 kU/day and plasma AGE was 27.2 ng/mL. Positive correlations were found between dAGEs and plasma AGEs, age, HbA1c, systolic blood pressure, macronutrients, energy, PWVcr and PWVfft. Negative correlations were found between dAGEs and (open full item for complete abstract)

Committee: Sarah Couch Ph.D. (Committee Chair); Abigail Peairs Ph.D. (Committee Member) Subjects: Nutrition

PHD, Kent State University, 2020, College of Education, Health and Human Services / School of Health Sciences

The purpose of the present study was to determine if unilateral upper-body acute RE would attenuate alterations in measures of cardiovascular function compared to bilateral upper-body acute RE. Twenty moderately active individuals completed upper-body maximal strength testing followed by two acute RE sessions. Measures of hemodynamics, autonomic modulation, central arterial stiffness, pulse wave reflection, and baroreflex sensitivity were measured at Rest and at 10- and 30-minutes during recovery. Interestingly, there were no significant condition by time interactions for any variable. Still, measures of hemodynamics, autonomic modulation, central arterial stiffness, pulse wave reflection and baroreflex sensitivity were significantly altered from Rest during recovery from upper-body acute RE. Specifically, the hemodynamic measure heart rate was augmented for at least 30 minutes. These changes were accompanied by alterations in measures of autonomic modulation specific to vagal activity, which were predominantly attenuated for at least 30 minutes. Further, central arterial stiffness was increased and measures of pulse wave reflection in terms of the pulse waveform were also augmented for at least 10 and 30 minutes, respectively. Other pulse wave reflection measures indicative of left ventricular function suggested an increase in myocardial workload and decrease in coronary blood flow for at least 30 minutes. Further, baroreflex sensitivity was reduced for at least 30 minutes. Collectively, this study suggests that unilateral upper-body acute RE does not seem to be an appropriate upper-body acute RE modality to reduce cardiovascular modulation compared to bilateral RE. Nevertheless, both modalities significantly altered cardiovascular function.

Committee: Derek Kingsley (Advisor); Jacob Barkley (Committee Member); Andrew Lepp (Committee Member) Subjects: Health Sciences

Doctor of Philosophy, Case Western Reserve University, 2019, Molecular Medicine

The beta-adrenergic receptor (bAR) exists in an equilibrium of inactive and active conformational states, which is modulated by ligands resulting in downstream signaling. In addition to cAMP, bAR regulates hypoxia-inducible factor 1 (HIF-1). We hypothesized that HIF-1 signaling occurs via a unique, independent bAR conformation and that Pulmonary Arterial Hypertension (PAH) patients with HIF-biased conformations would have blunted cAMP response. We found isoproterenol and salbutamol, both cAMP agonists, had opposing effects on HIF-1 in cells and mice. Additionally, hypoxia blunted agonist-stimulated cAMP in vitro, consistent with receptor equilibrium shifting towards HIF-activating conformations. bAR overexpression in cells increased HIF-1 activity and glycolysis which was blunted by HIF-1 inhibitors, suggesting increased bAR increases basal HIF-1 signaling. Because PAH is also characterized by HIF-related glycolytic shift, we dichotomized PAH patients in the PAHTCH trial (NCT01586156) based on right ventricular glucose uptake to evaluate bAR signaling. Patients with high glucose uptake had more severe disease than those with low uptake and had no response to bAR ligands. The findings expand the paradigm of bAR regulation and uncover a novel PAH subtype that might benefit from b-blockers. Circulating cell-free mitochondrial components are well characterized as mediators of inflammation. Recent studies show cells also release microparticles (MPs) containing intact mitochondria under conditions of stress or injury. However, detection of cell-free mitochondria and their cellular origin has not been studied in non-pathological conditions. Thus, we hypothesize that intact mitochondria are detectable in the circulation under physiological conditions. To test this, plasma MPs were analyzed via flow cytometry. Murine platelet-depleted plasma showed a small cluster of MPs which was 65% positive for the mitochondrial marker MitoTracker Green (MT Green). Additionally, transg (open full item for complete abstract)

Committee: Serpil Erzurum MD (Advisor); Sathyamangla Prasad PhD (Committee Chair); Kristin Highland MD (Committee Member); Bela Anand-Apte MBBS, PhD (Committee Member); Satish Kalhan MD (Committee Member) Subjects: Biology; Biomedical Research; Molecular Biology; Physiology

Master of Science (MS), Wright State University, 2019, Anatomy

Arterial spin labeling (ASL) is a magnetic resonance imaging (MRI) technique used for measuring cerebral blood flow (CBF) in a completely non-ionizing and non invasive fashion. ASL is useful in perfusion studies on healthy adult & pediatric subjects, individuals who need multiple follow-ups, and patients with varying cerebrovascular diseases where changes in CBF can be used as an indicator of tissue viability. We used a variation of the ASL technique known as pseudo-continuous ASL (pCASL). This form of ASL is the clinical standard (Alsop et al., 2015). However, it is not well documented the that pCASL is reliable between sessions spanning days to weeks. In this study, we assessed the inter-session reliability of CBF through the use of the pCASL technique. We hypothesize that the pCASL technique can be used to quantify CBF measurements across a 24-hour and 48-hour period. Subjects included 15 healthy, active duty Air Force military personnel recruited by the Wright Patterson Air Force Base from a larger experiment. Of the 15 subjects scanned on day 1 and day 2, 2 did not return for scanning on the third day. All participants were scanned in three identical evening sessions separated by 24 hours. MR imaging was conducted on a 3T MRI scanner with a 24-channel head coil. Each of the iv three days began with a baseline imaging scan followed by sham transcranial direct current stimulation (tDCS) and another identical imaging session. MRI acquisition included a 12-min resting-state function MRI (fMRI), three task fMRI, a T1-weighted MRI, diffusion tensor imaging (DTI), magnetic resonance spectroscopy (MRS) imaging, and resting pCASL. Our work only shows the baseline imaging from each day and the resting pCASL results. Quantitative CBF maps were computed from the raw pCASL data using proton density maps and a single compartment perfusion model through the use of the clinical processing pipeline on the MRI. These CBF maps w (open full item for complete abstract)

Committee: Kathrin Engisch Ph.D. (Committee Chair); Matthew Sherwood Ph.D. (Committee Co-Chair); David Ladle Ph.D. (Committee Member) Subjects: Anatomy and Physiology

Master of Science in Mechanical Engineering (MSME), Wright State University, 2017, Mechanical Engineering

The systemic circulation has a large number of vessels; therefore, 3-D simulation of pulse-wave propagation in the entire cardiovascular system is difficult and computationally expensive. Zero-Dimensional (Zero-D) and One-Dimensional (1-D) models are simplified representations of the cardiovascular network; they can be coupled as supplements to regional 3-D models for closed-loop multi-scale studies or be simulated as self-sufficient representations of the blood-flow network. Unlike Zero-D models, 1-D models can provide linear space-wise information for the vessels. However, Zero-D models can prove to be more useful in particular cases; as flexibility in adjusting parameters facilitate in tailoring the model to specific needs. A prevalent reservation regarding the Zero-D models has been the inconsistency of parameter adjustment. A primary objective of this work is to build a closed loop cardiovascular model with a consistent, easily replicable methodology so that the model (1) can be adopted in multi-scale studies and (2) can provide a quick clinical tool for patient-specific studies. Fifty-five large arteries were represented individually and the rest of the cardiovascular network was lumped into several equivalent components. This way, arbitrary parameter adjustments have been restricted to the microcirculation and venous sections only. The model was validated by comparing simulated hemodynamic properties with clinical measurements and simulations from a comparable 1-D model. The Zero-D simulations have been shown to be in excellent agreement with the 1-D predictions, despite their discrete nature in space being contrary to linearly continuous 1-D counterpart. An advantageous characteristic of the developed model is the retention of physiological definitions, especially for the arterial network. Therefore, the model can be conveniently modified for patient-specific simulations. The generality of the method and closed-loop nature of the model also allow to inquisit (open full item for complete abstract)

Committee: George Huang Ph.D. (Advisor); James Menart Ph.D. (Committee Member); Philippe Sucosky Ph.D. (Committee Member) Subjects: Biomedical Research; Fluid Dynamics; Mechanical Engineering

Master of Sciences, Case Western Reserve University, 2017, Clinical Research

Background Oral mono or combination therapy is recommended for patients with low or intermediate risk pulmonary arterial hypertension (PAH), but the specific drug choice remains controversial. We aim to assess long-term survival in PAH patients treated initially with a phosphodiesterase-5 inhibitor (PDE5i) or an endothelin receptor blocker (ERA). We also sought to identify responders to a specific type of drug. Methods Retrospective cohort study conducted at the Cleveland Clinic in group 1 PAH. Primary outcome was all-cause mortality according to initial treatment exposure. We adjusted for imbalances in baseline covariates via propensity score matching and weighting. Results The study population consisted of 91 patients treated with an ERA and 146 with a PDE5i (age 54 16 and 57 15 years, females 82% and 62%, respectively) between 2001 and 2015. Median follow up was 1304 days (interquartile range 606, 2058). There was no difference in survival after propensity score matching (HR 1.18 [95% CI 0.62, 2.25) or weighting (HR 0.88, [95% CI 0.48, 1.61]). There was a significant interaction between treatment and age (p = 0.002). The relative hazard ratio of death was lower with ERA therapy in patients younger than 45 years of age, and higher in patients older than 65 years of age. Conclusions After adjusting for baseline covariates, long-term survival was similar with initial treatment with an ERA or a PDE5i. However, younger patients had better survival when treated with an ERA, while the elderly survived longer with a PDE5i.

Committee: Thomas Love (Committee Chair); Raed Dweik (Committee Member); James Spilsbury (Committee Member) Subjects: Health Care; Medicine; Therapy

Doctor of Philosophy, The Ohio State University, 1986, Graduate School

Committee: Not Provided (Other) Subjects: Health Sciences

Doctor of Philosophy, The Ohio State University, 1974, Graduate School

Committee: Not Provided (Other) Subjects: Biology

Master of Science, University of Akron, 2016, Biology

Pharmaceutical medications in waterways are a growing problem worldwide. These include antibiotics, heart medications, and artificial steroids. We examined how a pair of commonly prescribed pharmaceuticals, phenylephrine and sodium nitroprusside, affected the heart and blood vessels in developing zebrafish, Danio rerio. The animals were exposed from 1 day post fertilization (dpf) to 6 dpf. Half of each treatment group was exposed to acute hypoxia on 8 dpf and 15 dpf. On 7 dpf, 8 dpf, 14 dpf, and 15 dpf, heart rate, end diastolic volume, end systolic volume, stroke volume, cardiac output, arterial diameter, and venous diameter were examined via inverted microscope. My results support the concern that pharmaceutical agents can cause physiological changes in locally exposed flora and fauna. Phenylephrine decreased heart rate and vasoconstriction in the veins and hypoxia caused a decrease in heart rate and vasodilation in the arteries.

Committee: Brian Bagatto Ph.D. (Advisor); Richard Londraville Ph.D. (Committee Member); Rolando Ramirez Ph.D. (Committee Member) Subjects: Biology; Environmental Science

Master of Science in Biomedical Engineering (MSBME), Wright State University, 2016, Biomedical Engineering

Most conventional cardiac assist devices today employ continuous flow blood pumps to supplement function in the dysfunctional heart. Continuous flow pumps are predominantly preferred to the original pulsatile pumps due to the smaller size (greater implantability) and higher efficiency they achieve. However, interest in the impact of vascular pulsatility on human health has arisen from the growing evidence of higher complications with nonpulsatile devices compared to pulsatile devices. Direct cardiac compression (DCC) offers a unique solution to the pulsatility issue through the application of force directly to the heart's surface. It is believed that employing the existing pump architecture of the heart better produces natural pulsatility than blood pumps in series with the heart. The purpose of this study was to determine if external cardiac compression by direct mechanical ventricular actuation (DMVA), produces arterial pulsatile quality to that of the naturally beating heart. This concept was tested using DMVA, a non-blood contacting DCC device capable of actively augmenting diastole, on an acute fibrillating model in nine large animals (seven canine and two swine). Hearts, being fibrillated in order to eliminate the heart's natural function to generate pulsatile blood flow, were supported by the DMVA device. Progressive myocardial weakening and acute failure throughout the experiment resulted from repeated cycles of fibrillation and defibrillation. Aortic pressures and flows were recorded periodically in ten second captures. Conventional measures of pulsatility (pulse pressure, energy equivalent pressure, surplus hemodynamic energy, frequency pulsatility index) were computed from these captures for comparison of arterial pulsatility between the naturally beating heart and the fibrillating heart supported by DMVA. Pulsatility in the naturally beating heart was measured from both the healthy normal heart and the weakened heart. Mean aortic flows and press (open full item for complete abstract)

Committee: David Reynolds Ph.D. (Advisor); Mark Anstadt M.D. (Committee Member); Chandler Phillips M.D. (Committee Member) Subjects: Biomedical Engineering

PhD, University of Cincinnati, 2015, Medicine: Molecular and Developmental Biology

Proper blood vessel development is crucial not only in embryonic development, but also in maintaining proper organ functionality throughout adulthood. The heart and blood vessels transport oxygen, metabolites, waste products, and immune response signals to all tissues of the body. Without proper development of arteries and veins, these functions would not be possible. This dissertation focuses on understanding how these two major vessel types are developed. We investigate the roles of two proteins, Stabilin-2 (Stab2) and Ets Varient 2 (Etv2), and how they function in relation to Vascular endothelial growth factor (Vegf) signaling to regulate vascular endothelial cell differentiation and arterial venous specification.

Committee: Saulius Sumanas Ph.D. (Committee Chair); Richard Lang Ph.D. (Committee Member); Jerry Lingrel Ph.D. (Committee Member); Joshua Waxman Ph.D. (Committee Member); Katherine Yutzey Ph.D. (Committee Member) Subjects: Developmental Biology

Master of Sciences, Case Western Reserve University, 2015, Clinical Research

Objective: Abnormalities in the prostacyclin pathway are involved in pathobiology of pulmonary arterial hypertension (PAH) and can be studied noninvasively by cutaneous treprostinil iontophoresis. Methods: Treprostinil iontophoresis was tested in 24 patients with idiopathic or heritable PAH and 25 age- and gender-matched controls, between 2/2013 and 2/2015. Results: The percentage change in perfusion units (PUs) with treprostinil iontophoresis was significantly reduced in IPAH patients compared with matched controls (median (interquartile range) 246 (96-605) versus 538 (381-1,035), p=0.004). The peak PUs were associated with NYHA functional class (R=-0.35, p=0.01), number of PAH therapies (R=0.48, p=0.02) and cardiac index (R=0.41, p=0.05, respectively). Lower peak PUs related to increased oxidative stress and arginine methylation products in plasma. Conclusion: Patients with IPAH have a decrease in the cutaneous microvascular response to treprostinil iontophoresis compared with matched controls; a finding that can be due to increased oxidative stress and abnormalities of the nitric oxide pathway.

Committee: Raed Dweik MD (Committee Chair); Wilson Tang MD (Committee Member); James Spilsbury PhD (Committee Member) Subjects: Health Sciences; Medicine

MS, University of Cincinnati, 2015, Medicine: Genetic Counseling

Background: Pulmonary Arterial Hypertension (PAH) is a disease that is characterized by obstruction of pre-capillary pulmonary arteries which leads to sustained elevation of pulmonary arterial pressure (mean >25 mm Hg at rest or >30 mm Hg during exercise). Early interventions have potential to help to mitigate the disease course if the individual is known to be at risk through diagnostic methods such as genetic testing. Current practice guidelines, which were created over 10 years ago, recommend genetic counseling and the option of genetic testing to individuals with heritable PAH, idiopathic PAH, and their family members. However, it is unclear if PAH specialists follow these recommendations. Thus, the objective of this research was to determine the utilization, knowledge, and perceptions about genetic counseling and genetic testing of PAH specialists. Methods: A survey was designed to evaluate PAH specialists' knowledge about the genetics of PAH as well as their practices and attitudes about genetic testing and genetic counseling for PAH. These PAH specialists include clinicians, health care coordinators, and researchers. The survey was distributed at the 2014 Pulmonary Hypertension Association International Conference and Scientific Sessions as well as online to members of the Pulmonary Hypertension Clinicians and Researchers and the Pulmonary Hypertension Professional Network via an email listserv. Parametric and non-parametric statistics were used to analyze responses, with comparisons of groups performed using the Wilcoxon rank sum test. Results: PAH specialists had low perceived and actual knowledge of the genetics of PAH with only 13.2% perceiving themselves as knowledgeable and 27% being knowledgeable. Although these specialists have positive or ambivalent attitudes about genetic testing and genetic counseling, they have poor utilization of these two genetic services. Physicians, who would be the primary specialists to utilize these genetic se (open full item for complete abstract)

Committee: Bill Nichols Ph.D. (Committee Chair); Lisa Martin Ph.D. (Committee Member) Subjects: Genetics

MS, University of Cincinnati, 2014, Medicine: Clinical and Translational Research

Selective intra-ophthalmic artery chemotherapy infusion (SIOAC) has been increasingly used in the management of retinoblastoma with the goal of minimization of therapy related toxicity and ocular salvage. Nineteen eyes in 17 patients with intraocular retinoblastoma received 87 SIOAC treatments between 2008 and 2013. While local reactions were common, mild and self-limited, rarer procedure-related adverse effects included bronchospasm, carboplatin anaphylaxis, transient lower extremity arterial thrombosis and reversible cerebral vasoconstriction. Neutropenia was more common with triple therapy cycles (melphalan, carboplatin and topotecan) when compared with single agent melphalan. Ocular salvage was achieved 11 of 19 eyes. Triple therapy was associated with improved rates of ocular salvage (p-value 0.0056). SIOAC can be effective therapy for intraocular retinoblastoma. Triple therapy seems more effective but also more myelosuppressive than single agent therapy. Larger scale clinical trials are necessary to better define the role of SIOAC.

Committee: Erin Nicole Haynes Dr.P.H. (Committee Chair); Adam C. Lane Ph.D. (Committee Member); James I. Geller M.D. (Committee Member) Subjects: Oncology

Doctor of Philosophy, Case Western Reserve University, 2015, Biomedical Engineering

Tissue perfusion is an important metric that can provide valuable information for disease diagnosis, treatment planning, and treatment follow-up. MRI can quantify perfusion both with and without Gd-based contrast agents, and can provide spatially-localized perfusion maps. However, these techniques are rarely used in the clinical environment. The works in this thesis focused on providing novel data acquisition and/or reconstruction techniques to overcome limitations in DCE MRI and ASL in order to provide clinically-viable perfusion exams. There are three main projects that will be described in this thesis. First, a simultaneous 3D magnetic resonance angiography and perfusion (MRAP) exam is proposed and is demonstrated in the distal lower extremities. Second, a 3D non-Cartesian parallel imaging method is described and used to achieve a low-dose, 3D, high spatiotemporal resolution renal DCE MRI exam that is acquired without breath-holding. Finally, a novel approach to ASL is proposed using the Magnetic Resonance Fingerprinting framework to simultaneously quantify perfusion, transit time, and tissue T1 in a single, efficient acquisition.

Committee: Vikas Gulani M.D., Ph.D. (Advisor); David Wilson Ph.D. (Committee Chair); Mark Griswold Ph.D. (Committee Member); Anant Madabhushi Ph.D. (Committee Member); Michael Martens Ph.D. (Committee Member) Subjects: Biomedical Engineering

Master of Science in Exercise and Health Studies, Miami University, 2014, Exercise and Health Studies

The purposes of this investigation were to determine if proxies for muscle fiber composition and anthropometric measurements can predict systolic (SBP) and diastolic blood pressure (DBP), pulse pressure(PP), and mean arterial pressure (MAP). We studied 370 Division I Male and Female Athletes from various sports. Multiple regressions were run to predict blood pressure from anthropometric variables and proxies for fiber type. SBP included Neck circumference, Arm span, and MaxVi (.663;43.4%); DBP included BMI, Arm Length, and Neck Circumference (.298;8.9%); PP included peak force, height, MaxVi, and Neck Circumference (.639;40.2%); and MAP included BMI and Neck Circumference (.458;20.5%). Blood pressure exists on a normal curve, and because natural characteristics like fiber type and anthropometric-characteristics affect blood pressure, their influence on normal homeostatic blood pressure should be considered in the determination of pathology from normal physiology and the evaluation of treatment options.

Committee: Ron Cox PhD (Committee Chair); Mark Walsh PhD (Committee Member); Thelma Horn PhD (Committee Member) Subjects: Biomechanics; Kinesiology; Physiology

PhD, University of Cincinnati, 2013, Engineering and Applied Science: Mechanical Engineering

Introduction. Pulmonary insufficiency (PI) causes myocardial dysfunction and hypertrophy in the right ventricle; with fatal consequences in some cases. The only remedy is pulmonary valve (PV) replacement surgery, the timing of which is critical. Surgery performed earlier than neces-sary leads to a re-emergence of PI, whereas a delayed intervention can potentially render the re-placement futile. There are no physiological markers to determine the correct window for this surgery. Clinicians currently rely on subjective assessment of cardiac MRI scans and evaluation of a few ad-hoc measures, such as end-diastolic pressure, cardiac volume and regurgitant frac-tion. The use of these different measures often results in conflicting conclusions and error-prone decisions. Thus, a quantitative index is required to unambiguously assess the progression of PI to determine the correct window for the PV replacement surgery. In this research, a set of energy-based endpoint were investigated that combined the pressure and volumetric measures. Right ventricular (RV) stroke work, energy loss in the branch pulmonary artery (PA) and a new end-point, energy transfer ratio defined as the ratio of the total blood energy at the main PA and stroke work were developed and tested as a proof-of-concept. Methods. The energy based endpoints were obtained for a normal and a diseased subject. Pres-sure measurements obtained invasively from cardiac catheterization, and flow rate and ventricu-lar volume obtained non-invasively from MRI scans were utilized for the calculation. Subsequently, methodologies to obtain these endpoints in a completely non-invasive ap-proach, using patient-specific image-based hemodynamic models were developed to eliminate the requirement of invasive catheterization. Angiographic MRI was used for geometry recon-struction for image-based models. Actual time- and spatially- varying velocity profiles, directly obtained from phase-contrast MRI were used f (open full item for complete abstract)

Committee: Rupak Banerjee Ph.D, P.E. (Committee Chair); Kan Hor M.D. (Committee Member); Michael Taylor M.D., Ph.D. (Committee Member); Teik Lim Ph.D. (Committee Member); Kumar Vemaganti Ph.D. (Committee Member); Janaka Wansapura Ph.D. (Committee Member) Subjects: Mechanical Engineering

PHD, Kent State University, 2013, College of Education, Health and Human Services / School of Health Sciences

Previous research suggests that physical activity may result in to decreases in arterial saturation (SaO2) and cerebral blood flow when exposed to a low oxygen environment between aerobically fit and unfit males. Purpose: The purpose of this study was to determine differences in SaO2, cerebral blood flow, minute ventilation (VE), and blood lactate between fit and unfit young males during exercise in hypoxia compared to normoxia. Methods: Apparently healthy college age males took part in two trials consisting of normobaric normoxia and normobaric hypoxia (12% oxygen). Fit (n = 3; VO2max = 51.5 ml ¿ kg-1 ¿ min-1 ± 3.1) and Unfit (n = 3; VO2max = 34.4 ml ¿ kg-1 ¿ min-1 ± 5.6) males cycled at 50% of their altitude adjusted VO2max (-26% of normoxia VO2max) for one hour after a two-hour baseline. Results: SaO2, cerebral blood flow, and RER were significantly decreased during hypoxia in all subjects (P < 0.05), but did not differ between groups. An interaction showed that Fit subjects had a higher SaO2 during exercise in hypoxia (P < 0.05). VE and lactate was greater during hypoxia (P < 0.05). The Fit group demonstrated a higher VE during exercise in hypoxia (P < 0.05). No differences in blood lactate were found between the two groups. Conclusion: The data suggests that when exposed to hypoxia aerobically unfit males may demonstrate decrements in oxygen utilization which may lead to decreases in physical activity and/or performance.

Committee: Ellen Glickman Ph.D. (Committee Chair); Jacob Barkley Ph.D. (Committee Member); John Gunstad Ph.D (Committee Member) Subjects: Environmental Health; Health; Physiology