Biomedical Engineering and Bioengineering Commons^™

Towards The Systematic Evaluation Of Variable Modes Of Mechanical Conditioning On The Compositional, Microstructural And Mechanical Properties Of Engineered Tissue Vascular Grafts., Sarah Saunders

Theses and Dissertations

Coronary artery bypass surgery (CABG) remains one of the most common cardiac surgical procedures performed worldwide, frequently involving multiple bypasses, and commonly employing the patient’s internal mammary artery, radial artery, or saphenous vein. CABG is often not possible because native vessels were already employed in previous interventions or are diseased themselves. Synthetic vascular grafts are currently integral tools of vascular surgery and have had relative success in large-caliber applications providing substantial benefit to aortic or iliac grafting; however, small diameter (< 6 mm) arterial grafts have not yet translated into clinical effectiveness due to thrombosis and anastomotic intimal hyperplasia. ETVGs present an exciting potential alternative in vascular grafting by offering a blood vessel substitute that could exhibit all the functional characteristics of native vasculature. In addition to relieving supply limitations associated with coronary artery bypass surgery ETVGs are especially ideal for pediatric patients with congenital heart disease who require grafts that grow as they do, eliminating the need for reoccurring invasive surgeries.

Though the role of biomechanics in regulating cellular behavior promoting non-thrombogenicity, vasoactivity, and ECM synthesis and maintenance is well …

Effect Of Viscoelasticity On Cellular Morphology And Activity, Thomas J. Petet Jr

Theses and Dissertations

It has been well established that there is a link between substrate stiffness and cellular activities such as proliferation, migration, and differentiation. Less characterized is the link between the time-dependent viscosity of a substrate with those cellular activities. To explore this, PDMS substrates were created with predictably tunable stiffness and viscosity parameters. A simulated model was also developed in parallel to explore the potential effects of viscosity in a computationally predictive way. It was found that the inclusion of viscosity caused a major paradigm shift to a non-zero substrate equilibrium that was sensitive to increases in the substrate stiffness. Finally, …

Therapeutic Approaches For Respiratory Distress Syndrome, Franck J. Kamga Gninzeko

Theses and Dissertations

Respiratory distress syndrome (RDS) is characterized by shortness of breath and low oxygen levels. RDS affects the neonatal and adult populations. In the neonatal population, RDS can be classified as NRDS (Neonatal respiratory distress syndrome), while in adults, it is known as ARDS (acute respiratory distress syndrome). This dissertation examines a therapeutic approach to NRDS and a mechanistic approach to ARDS with in vivo and in vitro models of lung injury. NRDS is characterized by a deficiency or lack of surfactant. Surfactant is an essential compound composed of phospholipids and proteins to prevent the lungs from collapsing. There are several …

Hydrology And Water Quality Analysis In The Big Black River Watershed, Mississippi, Moniba Shabbir

Theses and Dissertations

Evaluating hydrology and water quality for the Big Black River Watershed in Mississippi was accomplished by using the Better Assessment Science Integrating Point and Nonpoint Source (BASINS 4.5), Loading Simulation Program in C++ (LSPC), and Water Quality Analysis Simulation Program (WASP) models. The watershed model calibration was originally accomplished by using historical data collected from U.S. Geological Survey (USGS). The watershed model was calibrated using data from 2000 through 2018 in order to quantify stream flow and point source discharges under a variety of hydrologic conditions. The model predicted response of hydrology was consistent with the observed data range. The …

Design Of Plastic Contaminant Eliminator In Seed Cotton, Joshua H. Tandio

Theses and Dissertations

Plastic contamination in cotton is a problem in cotton industry and researchers have worked on this problem with different approaches. This thesis documents the design of mechanical and electronic real-time systems for detecting and removing plastic contaminants. The mechanical system was designed to expose plastic embedded inside the seed cotton to the sensor and to separate plastic contaminated cotton from the process stream. The detection system consisted of an embedded computer interfaced with a USB camera and Neural Network (NN) software running in it. Two NN models were tested, a transfer learning model and a built-from-scratch original model. The original …

An Innovative Triboelectric Stent Sensor: Prospective Cardiovascular Health Monitor Device, Ulises Vidaurri Romero

Theses and Dissertations

Previous research that has focused on TENGs have lacked the proper application of this energy generator. Currently, heart disease remains the leading cause of death in the United States. With increasing demand for self-sustainable medical devices, this nitinol health monitor sensor device (NHMS) integrates the TENG applications with medical applications. The NHMS features memory shape nitinol electrodes that preserves the device structure while using PDMS and PVDF triboelectric effect to measure heart rate, blood pressure, and breathing patterns. Three constant pressures were measured in this study. At a constant pressure of stage 1, the NHMS produces an average AC of …

The Immune Modulatory Role Of Endocannabinoid Anandamide To Suppress Inflammation Through Regulation Of Microrna And Microbiome, Muthanna Ali Sultan

Theses and Dissertations

Cannabinoids are group of compounds that exerts their anti-inflammatory action through activation of CB1 and CB2 receptors and other minor receptors. In the current study, we investigated the effect of Anandamide (AEA) on Acute Respiratory Distress Syndrome (ARDS) induced by exposure to Staphylococcus Enterotoxin B (SEB) intranasally. We found that C57BL/6 mice treated with AEA showed improvement in the clinical functions of the lungs, accompanied by a decrease in the infiltration of inflammatory cells in the lung tissue, and a decrease in the secretion of pro-inflammatory cytokines. Furthermore, AEA regulated the miRNA profile of the mononuclear cells in the lungs …

Delivery Optimization And Evaluation Of Biomechanics Of An Injectable Nucleus Pulposus Replacement Device, Zachary Rustin Brown

Theses and Dissertations

Lower back pain effects up to 80% of people at some point in their life, a majority of cases being the result of degenerative disc disease. Treatment options for degenerative disc disease are limited, jumping from physical therapy to major spinal fusion and total disc replacement surgery with little to no approaches in between. Furthermore, surgical treatments have not shown to be more effective than conservative treatments and reducing pain and disability over the long term. Hydrogels have shown promise as a potential nucleus pulposus replacement device. Their properties are controllable and can be implanted into the body through minimally …

Mechanical And Material Characterization Of Advanced Materials For Tissue Regeneration, Bailey Kylara Ricketts Jackson

Theses and Dissertations

In natural disasters and military deployment operations, injury to long bone can cause extensive damage and be difficult to treat and heal quickly. Explosive devices and trauma often produce long-bone (>2-cm length) wounds that are more complicated than common fractures. Due to the size and complexity of these injuries, they can be difficult to treat in a battlefield environment and take a long time to heal completely and properly. Even after the long healing period, these injuries often require rehabilitation to strengthen the muscles that have weakened in the wounded limb. For military applications especially, these effects can put …

Engineering A High-Throughput Screening Platform For Assessing Developmental Neurotoxicity Throughout Head- Regeneration In Schmidtea Mediterranea, Johnathan James Morris

Theses and Dissertations

The increase in commercially used chemicals that are inadequately evaluated for safety and risk to development has created a reticent threat to human health. Addressing these deficiencies is compounded by limited methodologies to determine the etiology of exposure-related developmental neurotoxicity (DNT). Current means of assessing DNT are largely retrospective and limited by the expensive, time-consuming, and labor-intensive use of laboratory animal models, thereby motivating a global research effort to produce alternative chemical screening assays. In this work, we have developed a novel high- throughput platform that serves as a new tool to evaluate the effects of exogenous chemical exposure on …

Effect Of Obesity On Knee Joint During Walking And Squatting, Simon Vasquez Iii

Theses and Dissertations

This paper analyzes the effect of obesity on the knee joints during squats. This was performed on 2 different subjects by having each squat 30 times at their decided comfortable depth to display some fatigue and effects on the knee joints. Using the VICON NEXUS and AMTI force plates equipment at The University of Texas at Rio Grande Valley Biomechanics Lab, the center of pressure, knee flexion angles, velocity, and ground reaction forces were calculated. The subjects performed the exercises with and without additional weight using a body vest and kettlebell. The ground reaction forces showed a significant increase in …

Regulation Of Inflammatory Processes By Tryptamine, Cannabidiol And 2,3,7,8-Tetrachlorodibenzo-P-Dioxin, Nicholas Dopkins

Theses and Dissertations

Host immunity is a complicated system of pro-inflammatory and anti-inflammatory processes that respond to exogenous and endogenous threats to regulate host physiology, inhibit carcinogenesis, and protect from infections. Sustained deviance from normal immunological function occurs due to a variety of factors both endogenous and exogenous, with some factors that can dysregulate host immunity including: genetics, microbiota composition, toxin exposure, age, gender, and smoking. The etiology of inflammatory disorders is both convoluted and complex due to the sheer number of facets regulating host immunity. To better contribute to understanding how immunological dysregulation occurs we focused on how three anti-inflammatory compounds (tryptamine, …

Anatomical Correlates Of Age-Related Basal Forebrain Dysfunction, Brandy Lynn Somera

Theses and Dissertations

The basal forebrain (BF) is comprised of several nuclei including the substantia innominata, medial septum, nucleus basalis and diagonal band of broca which are involved in cognitive functions including attention, motivation, and arousal. BF neurons are particularly vulnerable to dysfunction and degeneration in aged humans and, more dramatically, in diseases such as Alzheimer's disease (AD). Age-related BF dysfunction may reflect diminished afferent regulation as well as an altered local glial environment. Our lab has previously shown reduced orexin/hypocretin innervation of BF in aging, a phenomenon that may link afferent dysfunction with altered microglial homeostasis. There is little research examining these …

An In Vitro Approach To Vascular Therapeutic Testing, Shahd Ali Hasanain

Theses and Dissertations

Aortopathies refer to a broad class of pathological conditions affecting the aorta and are a major cause of morbidity and mortality in the US. Specifically, aortic aneurysms and aortic dissections have diverse etiologies that are initiated by alterations in the tissue’s extracellular-matrix (ECM) proteins, namely collagen and elastin, thereby predisposing the aortic wall to weaken and rupture. Pentagalloyl glucose (PGG) has recently emerged as a non-surgical treatment to reduce the risk of dissection or rupture. PGG is a known antioxidant and anti-inflammatory which has been shown to have ECM-restorative qualities that enhance collagen and elastin’s functional properties. Prior studies using …

Pseudomyxoma Peritonei Derived Cancers: A Novel Study On Growth And Growth Suppression Utilizing Common Colorectal Cancer Agents, Raymond Kennith Bogdon

Theses and Dissertations

Pseudomyxoma peritonei is a devastating gastrointestinal disease characterized by the production of mucinous ascites within the peritoneal cavity. Historically, this condition is discovered in the advanced state due to the lack of adequate screening tests and typically presents as an enlarged abdomen and with symptoms of gastrointestinal distress. Treatment for this disease is a combination of cytoreductive surgery and heated intraperitoneal perfusion chemotherapy, but a successful operation does not guarantee full remission of this malignancy. This study focuses on 3 untested variants of PMP cancer, and 2 mucinous colorectal adenocarcinomas that had invaded into the peritoneal cavity. Clinical presentation of …

Stress Analysis Based On Ecg And Eeg, Eyad Talal Attar

Theses and Dissertations

Stress is a significant risk factor for various diseases such as hypertension, heart attack, stroke, and even sudden death. In many studies, stress is linked to decision making, performance, and learning. The heart rate variability (HRV) can be measured from the Electrocardiogram (ECG) and is defined as the variation of the interval between two consecutive heartbeats (heart rate). Heart rate variability is also an indicator of the balance between the sympathetic and parasympathetic branches of the autonomic nervous system. HRV refers to variations of heart rate in a certain amount of time. Heart rate variability (HRV) is a relatively new …

Endothelial Response In 2d And 3d To Doses Of Photosensitive Carbon Monoxide Releasing Molecules With Improved Activation, Nicholas Duc Huynh

Theses and Dissertations

Cardiovascular disease (CVD) is the leading cause of death worldwide in large part due to atherosclerotic obstruction of blood vessels. Limitations with current treatment approaches include restenosis in stenting and viable donor-tissue for bypass grafts, and this has motivated research combining the fields of drug delivery and tissue engineering for alternative approaches. The use of carbon monoxide as a potential therapeutic agent in the treatment of CVD has shown potential impacts on vasodilation and anti-inflammation. The goal of this study was to develop a system to elucidate the response of endothelial cells post-exposure to different concentrations of carbon monoxide releasing …

Effects Of Stiffness And Cell Shape On Cellular Mechanosensing, Sarah Lynn Furman

Theses and Dissertations

Cellular mechanosensing is the process of converting mechanical signals into biological responses. Stem cells are self-renewing cells with the potential to transform into specialized cell types - this differentiation process is influenced by cellular mechanosensing. Cells sense material stiffness, and stiffer environments result in increased cellular mechanosensing and preferential differentiation into bone-producing osteoblasts. Cell shape also plays an important role due to its influence on cytoskeletal contractility, and photopatterning can be used to study the effects of cell shape on cellular mechanosensing. Although the effects of material stiffness and cell shape have been studied, little is known about the joint …

Porous Scaffold And Soft Hydrogel Composite For Biomedical Applications, Matthew Dicerbo

Theses and Dissertations

Biophysical signals including stiffness and dimensionality influence a myriad of stem cell behaviors including morphology, mechanosensing, and differentiation. 2D stiff environments cause increased cellular spreading and induce osteogenic differentiation whereas 3D soft environments favor rounder cell morphologies attributed to a chondrogenic phenotype. The goal of this study is to create a composite that integrates these divergent biophysical signals within one system. This composite consists of a stiff and porous polycaprolactone (PCL) backbone that provides mechanical stiffness and a 2D environment. The PCL backbone is then perfused with mesenchymal stem cells (MSCs) and a soft methacrylated gelatin (GelMe) hydrogel to provide …

Design Of A Pneumatic Soft Robotic Actuator Using Model-Based Optimization, Mahsa Raeisinezhad

Theses and Dissertations

In this thesis, the design and optimization process of a novel soft intelligent modular pad (IntelliPad) for the purpose of pressure injury prevention is presented. The structure of the IntelliPad consists of multiple individual multi-chamber soft pneumatic-driven actuators that use pressurized air and vacuum. Each actuator is able to provide both vertical and horizontal motions that can be controlled independently. An analytical modeling approach using multiple cantilever beams and virtual springs connected in a closed formed structure was developed to analyze the mechanical performance of the actuator. The analytical approach was validated by a finite element analysis. For optimizing the …

Engineering A Prophylactic Cap For Multi-Dose Vial Disinfection, Rebecca Lee Charboneau

Theses and Dissertations

Recently, multi-dose vials (MDVs) have demonstrated significant bioburden, with randomized studies revealing bacterial contamination rates up to 27%. When the proper protocol of disinfecting the vial diaphragm with a pre-saturated wipe is followed, MDV bioburden is eliminated. However, when this sterilization protocol is neglected, the susceptibility of MDV to house potential nosocomial pathogens intensifies. In this work, the usability and effectiveness of a novel device, referred to as the Vial Cap, are investigated to gauge the feasibility and acceptability of this device as a method of MDV disinfection. The usability of the Vial Cap was evaluated using principle human factors …

Effects Of Genipin Crosslinking On The Properties Of Tendon Derived Extracellular Matrix Hydrogels, Alicia Cheyenne Coombs

Theses and Dissertations

Extracellular matrix (ECM) hydrogels are a useful biomaterial in the tissue engineering field used for injectables in drug delivery systems, wound dressing, tissue regeneration and many other applications. ECM hydrogels are highly biocompatible, contain proper ratios of biomolecules required for complex bioactivity of tissues and they promote tissue repair. However, ECM hydrogels typically have poor mechanical strength, which leads to hydrogel instability, and a limitation in their ability to be modified for translational applications. In this research, genipin, a natural crosslinker derived from plants, was utilized in an attempt to improve upon the mechanical limitations of ECM hydrogels. Genipin has …

A Comparative Study To Assess The Osteogenic Potential Of Competing Bioceramics For Bone Tissue Engineering, Nashaita Patrawalla

Theses and Dissertations

Biomimetic composite scaffolds comprising of bioactive ceramic-based materials incorporated within a polymeric framework have shown considerable promise for use in bone tissue engineering (BTE) applications. Although bioceramics have shown immense promise for use in BTE, few studies have performed a head-to-head comparison of the osteogenic properties of the most promising bioceramic materials. The goal of this study was to compare three different bioceramics – Bioglass 45S5 (BG), Laponite XLG (LAP), and β-Tricalcium Phosphate (TCP) – on the physical properties (i.e., swelling, stability, compressive modulus, bone bioactivity) of methacrylated collagen (CMA) hydrogels and osteogenic differentiation of human MSCs (hMSCs) encapsulated within …

Validation Of Arterial Distensibility Neural Network Model With Clinical Data, Cassondra Michelle Petersen

Theses and Dissertations

Cardiovascular diseases continue to plague the world as the number one killer of adults each year. As cardiovascular diseases can start with seemingly no symptoms, heart disease has been coined as the silent killer. With the ongoing COVID-19 global pandemic, the need for advances in cardiovascular advances has become even more prevalent as this virus is known to cause more severe damage to those who have underlying cardiovascular problems. These two reasons show the dire clinical need for researchers to continue to use novel techniques such as neural networks to find new approaches for helping physicians non-invasively and quickly add …

Cardiovascular Intelligence: Novel Quantitative Cardiology, Deep Learning And Machine Learning Models To Predict Clinical Outcomes, Vignesh Balasubramanian

Theses and Dissertations

Arterial compliance has been recognized as a critical parameter in governing pulsatile flow dynamics. It has traditionally been assumed constant throughout the cardiac cycle. Its computation has been based either on the classic Windkessel model in diastole or the stroke volume over pulse pressure method in systole. We proposed a novel compliance-pressure loop (CPP loop) approach to quantify arterial compliance and compare it to existing linear and nonlinear methods. This was followed by an analysis of increased pulse wave reflections in hypertension due to impedance mismatching and how the effective energy transmission to the vasculature is compromised. Their quantification in …

Bioink Optimization And Effects Of Microgravity On 3d Bioprinted Cell Laden Constructs, Likitha Somasekhar

Theses and Dissertations

Bioengineered 3D tissue constructs have gained attention as in vitro tools for the study of cell-cell and cell-matrix interactions and are being explored for potential use as experimental models for mimicking human tissues. One of the main problems in tissue engineering is the necessity to vascularize complex engineered tissues and sacrificial printing has been recognized as a possible solution to vascularization of the bioprinted tissues. Research studies have demonstrated that exposure to microgravity in space induces adaptive alterations in vascular structure and function. Changes in the morphology and gene expression is observed when endothelial cells are exposed to microgravity and …

Vascular Endothelial Dysfunction And Effects On Arterial Wall Microstructure, Jeffrey Thomas Rodgers

Theses and Dissertations

Vascular endothelial cell dysfunction (ECD) is a disease characterized by the inability of the vascular endothelial cells to transmit signaling molecules, namely nitric oxide (NO), in response to changes in blood flow rate. This disease is shown to be incident in the onset of more severe vascular disease such as hypertension, atherosclerosis, and heart failure. Long-term ECD is shown to cause long-term remodeling such as decreased flow-mediated dilation, increased pulse-wave velocity, intimal-medial thickening, and increased wall stiffness due to collagen deposition. We used second harmonic generation (SHG) microscopy to analyze this change in the collagen microstructure of the arterial extracellular …

Age And Sex Dependency Of Thoracic Aortic Aneurysm Progression In A Mouse Model Of Marfan Syndrome, Nazli Gharraee

Theses and Dissertations

Aneurysm of the ascending aorta is the most common type of thoracic aortic aneurysm, and it is a life-threatening manifestation of Marfan syndrome (MFS), a connective tissue disorder caused by mutation of the FBN1 gene. Incidence of Marfan syndrome is similar for men and women; however, men suffer from more severe aortic events compared to women.

This study aims to provide a better understanding of age and sex dependency of cell and extracellular matrix alterations of the aortic wall during the progression of the aneurysm caused by Marfan syndrome. To achieve this goal, the C1041G/+ mouse model of Marfan syndrome …

Defining The Pathophysiology Of Gut Humoral Immunodeficiency, Ahmed Dawood Mohammed

Theses and Dissertations

Mucosal antibodies maintain gut homeostasis by promoting spatial segregation between host tissues and luminal microbes. Antibody-deficiency is the most common form of primary immunodeficiency observed in humans. In antibody-deficient humans, abnormal composition of the gut microbiota ('dysbiosis') is associated with chronic inflammatory responses and gastrointestinal complications. However, the mechanisms by which dysbiosis promotes inflammatory disease are poorly defined. In the studies described in this dissertation, we utilize CD19-/- mice as a model of antibody deficiency to test the hypothesis that antibody deficiency negatively impacts gut physiology under steady-state conditions. Chapter #1 is an overview of B cell development and how …

Mechanism Of Therapeutic Efficacy Of New Drugs In Glioblastoma, Firas Hameed Khathayer

Theses and Dissertations

Glioblastoma is the most malignant and prevalent brain tumor in adults. It can grow and spread quickly causing harm to brain health. The deregulation of epigenetic mechanisms is considered the main agent in the developing of GBM. One of the enzymes involved in epigenetic alternation and cancer development are histone deacetylases enzyme (HDAC) by removal acetyl group from histone and create condensed chromatin that suppresses transcription gene to histone and non-histone proteins involved in tumorigenesis. Histone deacetylase inhibitors (HADCi) are the most common therapeutic methods for many types of cancer treatments. In the present study, we used relative HDAC inhibitor …