Biomedical Engineering and Bioengineering Commons^™

Quantification Of Dynamic Changes Of Hemodynamic And Metabolic Responses To Brachial Artery Occlusion: A Broadband Near-Infrared Spectroscopy Study, Caroline Elizabeth Carter

Bioengineering Theses - Archive

Cardiovascular disease (CVD) is a leading cause of death in the United States, and non-Hispanic African Americans are at higher risk than other racial and ethnic groups. Endothelial dysfunction is a major contributor to CVD development and progression. Remote ischemic pre/conditioning (RIC), which involves exposing cells or tissues to brief sublethal stress, has been shown to protect cardiovascular cells from ischemia and reperfusion injury, including CVD. This study aimed to investigate hemodynamic and metabolic dynamics in response to 5-min forearm arterial occlusion using broadband near-infrared spectroscopy. My thesis is a tripartite investigation that weaves RIC, mitochondrial dynamics, and health disparities …

Formation And Morphological Changes Of Stress Actin Filaments In Adipose-Derived Stem Cells, Adam Priester

Bioengineering Theses - Archive

Adipose-Derived Stem Cells (ADSCs) are a sub-type of stem cell that can be collected and isolated from the adipose tissue. Adipogenesis describes the commitment and differentiation of stem cells, including ADSCs, toward the adipocyte lineage. While much research has been completed on this process in the long term (>2 weeks), morphological changes of adipogenesis during the early phase (<24 hours) are lacking in the literature and remain to be elucidated. The current study focuses on these changes in the early and later stages of adipogenesis using adipogenic differentiation factors and fluorescent imaging analyses. Quantifiable data on morphological changes during both phases can provide insight into how these changes affect later differentiation and lay the groundwork for additional research in this area. Using fluorescent image analysis, it was shown that the eccentricity of ADSCs, a measure of cellular circularity, decreases exponentially in the early phase of adipogenesis. In contrast, the cellular area appears to increase exponentially during the same early period. During the later stages of differentiation, it was shown that actin filament length decreases exponentially and the ratio of lipid to actin length increases exponentially, demonstrating that lipid accumulation outpaces actin filament shortening and increasing circularity during the later stages. These findings may be used in future studies to further define the role of actin filament-mediated morphological changes and mechanobiology during adipogenesis.

Investigation Of Rate Pressure Product As A Metric To Quantify Cardiac Workload In Sleep Apnea Events, Carlos Cruz

Bioengineering Theses - Archive

An investigation on the use of rate pressure product (RPP) to measure the cardiac workload in sleep apnea patients is presented. RPP is the product of systolic blood pressure (SBP) and heart rate (HR). The application of RPP to quantify cardiac workload is combined with the detection of respiratory events occurring in close proximity (less than 30 seconds apart). These two combined factors provide a unique framework for analyzing sleep apnea events and are the primary novelty of the study. Close proximity events are referred to as respiratory event chains (RECs). Statistical analyses were conducted on various RPP metrics as …

The Effects Of Poloxamer 188 On Wound Closure In A Mouse Brain Endothelium Model, Mia Claire Grubbs

Bioengineering Theses - Archive

The blood-brain barrier (BBB) plays a crucial role in maintaining central nervous system homeostasis and, if structurally and functionally compromised, can lead to severe neurological consequences. This thesis explores the therapeutic potential of Poloxamer 188 (P188) in the context of BBB wound healing. P188, FDA-approved copolymer that is known for its cytoprotective properties, is examined for its impact on endothelial monolayers through in vitro scratch wound assays. The study aims to establish a consistent endothelial monolayer model, quantify wound healing dynamics, and assess the efficacy of P188 at varying concentrations. The thesis goals include detailed methodologies such as cell culture …

Novel Implementation Of Additive Manufacturing To Visualize The Human Brain Connectome, Greg Tyler

Computational and Data Sciences (MS) Theses

Additive manufacturing (AM) is an emerging technology with diverse areas of application. In this paper we explore a new application of AM that uses a subset of AM known as 3D printing, to create real life models of the human connectome. The human connectome is a color coded map of the connections in the human brain where directions are indicated by colors and the density of connections are indicated by color intensity.

There are several different algorithms for mapping the connections and describing the output. The Neu- roImaging Tools and Resource Collaboratory (NITRC) provides one such algorithm. It uses probabilistic …

An Improved Saliency Map With Trustworthiness For Localizing Abnormalities In Medical Imaging, Nolan C. Skelly

Theses and Dissertations

Saliency maps are a widely used methodology to make deep learning models more interpretable. They provide post-hoc explanations through identification of the most pertinent areas of an input medical image. These techniques have been assessed based on 1) localization utility, 2) sensitivity to model weight randomization, 3) repeatability, and 4) reproducibility. Ten saliency map techniques will be tested, Grad, Smooth Grad, Integrated Gradients, Smooth Integrated Gradients, XRAI, Grad-CAM, Guided Backpropagation, Guided GradCAM, GradCAM++, and ScoreCAM. The neural networks used to predict and read medical information require a reliable solution to provide medical practitioners intelligible results. Using the information of two, …

Investigating The Effects Of Collagen Alignment And Tricalcium Phosphate Incorporation On Osteoblast Cell Response, Kathryn Elizabeth Bock

Theses and Dissertations

Every year, over 20 million people globally are affected by bone tissue loss due to disease or trauma. Bone tissue engineering (BTE) is touted as a promising approach to promote bone tissue repair and regeneration. In this realm, development of collagen-based scaffolds incorporated with a bioceramic is often attempted to generate tissue scaffolds that resemble the organic and inorganic composition of native bone. In addition, a variety of different collagen processing techniques have been employed to produce anisotropically aligned scaffolds that can provide the essential biochemical and structural cues to guide cell response. While there have been numerous studies on …

Development Of A Physics-Informed Neural Network For Prediction Of Blood Flow, Marcello Vittorio Mattei Di Eugenio

Theses and Dissertations

Abstract—Objective: We propose a new neural network architecture that accepts point clouds and outputs 3D velocity profiles for aneurysm geometries. Methods: We generated a synthetic aneurysm 3D flow dataset using CFD and used it to train our model architecture and compare it with other popular architectures like U-net and PointNet. We incorporate tools for improving model performance such as incorporating a distance function, a physics-informed loss to enforce the law of mass conservation, and the Huber loss to learn patterns across heterogeneous velocity components of multiple dimensions. Results: The tools implemented together with our architecture achieved the best performance on …

1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine (Mptp)-Treated Adult Zebrafish As A Model For Parkinson’S Disease, Emmeline Bagwell

All Theses

The use of adult zebrafish, Danio rerio, as a model for human neurodegenerative diseases has proven valuable in pharmaceutical development and genetic disease research due to their high genetic homology to humans, cost-effective husbandry, and quick life cycle breeding times. Despite their promise, most zebrafish research has focused on embryonic stage organisms, primarily due to the ease of direct handling protocols and rapid progression through developmental stages. Recognizing the limitations of early-stage organisms in modeling adult diseases, recent efforts have shifted the applicability of zebrafish models, particularly for Parkinson's Disease, due to the nature of the disease impacting patients 55 …

Medical Simulation-Based Sensor Methods For Ultrasound-Guided Dialysis Cannulation Skill Assessment, Devansh Shukla

All Theses

End-stage kidney disease (EKSD) is the final, permanent stage of chronic kidney disease (CKD), where the body's kidneys cannot filter blood sufficiently. Hemodialysis treats ESKD by filtering wastes and water from your blood externally via a dialyzer. Patients on hemodialysis require a vascular access, typically an arteriovenous fistula (AVF) or arteriovenous graft (AVG) for dialysis, which is used three times a week for about four hours a session. These life-saving therapies can be quite tedious, especially for elderly patients and patients with co-morbidities. As such, successful cannulation is extremely important to ensure the longevity of the patient's vascular access and …

A Wearable Fluorescence Imaging Device For Intraoperative Identification Of Human Brain Tumors, Mehrana Mohtasebi, Chong Huang, Mingjun Zhao, Siavash Mazdeyasna, Xuhui Liu, Samaneh Rabienia Haratbar, Faraneh Fathi, Jinghong Sun, Thomas A. Pittman, Guoqiang Yu

Biomedical Engineering Faculty Publications

Malignant glioma (MG) is the most common type of primary malignant brain tumors. Surgical resection of MG remains the cornerstone of therapy and the extent of resection correlates with patient survival. A limiting factor for resection, however, is the difficulty in differentiating the tumor from normal tissue during surgery. Fluorescence imaging is an emerging technique for real-time intraoperative visualization of MGs and their boundaries. However, most clinical grade neurosurgical operative microscopes with fluorescence imaging ability are hampered by low adoption rates due to high cost, limited portability, limited operation flexibility, and lack of skilled professionals with technical knowledge. To overcome …

Representativeness Evaluation Of Delta-Flux Eddy Covariance Towers For Assessing Greenhouse Gas Emissions From Rice Fields In The Mid-South Region, Katherine Skiles

Biological and Agricultural Engineering Undergraduate Honors Theses

Rice grown in 5 states across the Mid-South (AR, LA, MS, TX, and MO) account for nearly 80% of all domestic U.S. rice production. Methane emissions produced during rice farming and the large seasonal water demand to maintain flooded fields have created a need for alternative irrigation research that can reduce methane emissions and conserve water. Structures called eddy covariance towers (ECTs) can observe methane and other flux responses to changing irrigation styles, and their data is shared across flux tower networks such as Delta-Flux in the Mid-South. The Delta-Flux network is relatively new, and its data-sharing capacity is not …

Determining The Effects Of Glycocalyx Modifications On The Electrophysical Properties Of Human Mesenchymal Stem Cells, Rominna E. Valentine Ico

Electronic Theses, Projects, and Dissertations

Human mesenchymal stem cells (hMSCs) have gained popularity in clinical trials due to their multipotent differentiation characteristics, ability to secrete bioactive molecules, migrate into diseased or damaged tissues, and their immunosuppressive properties. HMSC cultures are heterogeneous, containing stem cells, partially differentiated progenitor cells, and fully differentiated cells. One of the major challenges with hMSCs therapeutic potential is the inability to select specific cell subpopulations due to an insufficient number of biomarkers. Often the biomarkers used, like those for fluorescence-activated cell sorting, are not sufficient to define hMSCs because they overlap with other cell types. Consequently, there is a need to …

Controlled Manipulation And Transport By Microswimmers In Stokes Flows, Jake Buzhardt

All Dissertations

Remotely actuated microscale swimming robots have the potential to revolutionize many aspects of biomedicine. However, for the longterm goals of this field of research to be achievable, it is necessary to develop modelling, simulation, and control strategies which effectively and efficiently account for not only the motion of individual swimmers, but also the complex interactions of such swimmers with their environment including other nearby swimmers, boundaries, other cargo and passive particles, and the fluid medium itself. The aim of this thesis is to study these problems in simulation from the perspective of controls and dynamical systems, with a particular focus …

Exploring The Potential Of Tesla Valve For Filtering And Sorting Microscale Active Swimmers: A Computational Study, Ariel Rogers, Zhiyao He, Yong Wang

Physics Faculty Publications and Presentations

It is well-known that a Tesla valve allows fluids to flow unidirectionally without moving parts; however, how Tesla valves interact with active matters and the potential applications of Tesla valves in biology remain largely unexplored. Here, we present a computational study on the potential use of Tesla valves for filtering and sorting microscale active swimmers such as bacteria. We investigated the behavior of microscale swimmers passing through the Tesla valve at different linear and angular velocities using numerical simulations and quantified the diodicity of the Tesla valve for active swimmers. Our results demonstrate that the Tesla valve can effectively filter …

Process-Structure-Property Relationships Of Nanofibers For Biomedical Applications, Dipasree Bhowmick

Theses and Dissertations

This thesis explores the fabrication, characterization, and applications of nanofiber membranes utilizing Forcespinning® technology. Two distinct nanofiber systems were developed and evaluated, one focusing on pH-responsive Eudragit-baicalin loaded nanofibrous membranes for wound healing and the second one on thermo-responsive nanofiber-hydrogel (PNIPAAm) systems for biosensing applications, specifically dopamine detection. In the first project, nanofiber membranes loaded with Eudragit and baicalin demonstrated superior antibacterial properties against both gram-negative (E. coli) and gram-positive (B. meg) bacteria. Additionally, these membranes exhibited antioxidant properties and enhanced cell proliferation of 3TT cells, making them promising candidates for wound healing dressings. In the second project, a …

Using Noninvasive Calibrated Cuff Plethysmography To Observe The Effects Of Cold-Water Immersion On Arterial Compliance, Rita M. Grigorian

Biomedical Engineering: Graduate Reports and Projects

As the prevalence of cardiovascular diseases continues to exponentially grow in populations across the globe, the necessity of determining underlying factors, effective methods of diagnoses, and universally available preventive measures also grows. Early detection of endothelial dysfunction, a proven precursor of cardiovascular diseases, can be extremely impactful in encouraging preventative measures and early intervention before medical conditions become chronic. In recent years, ice plunging, a form of cryotherapy involving full body immersion in cold water, has gained popularity within circles of fitness and health practitioners, gaining the interest of people of all backgrounds. Certain parallels observed between the human physiological …

Structural Characterization Of Cardiomyocyte Microenvironment In Murine Myocardium By Multimodal Stimulated Emission Depletion Microscopy, Zhao Zhang

All Dissertations

Cardiomyopathy, a disease of the heart muscle, is characterized by structural and functional abnormalities of the myocardium, in the absence of coronary artery disease, hypertension, valvular disease or congenital heart disease. In 2020, there were approximately 6.11 million prevalent cases of cardiomyopathy and myocarditis, and 0.37 million related deaths worldwide. Many affected individuals are asymptomatic, and chronically treated patients are at risk of heart failure. Within the myocardium, cardiomyocytes reside in a complex and dynamic extracellular matrix (ECM), consisting of basement membrane and interstitial matrix. The interactions between cardiomyocytes and myocardial ECM play a critical role in maintaining cardiac geometry …

Ti-6al-4v Β Phase Selective Dissolution: In Vitro Mechanism And Prediction, Michael A Kurtz

All Dissertations

Retrieval studies document Ti-6Al-4V β phase dissolution within total hip replacement systems. A gap persists in our mechanistic understanding and existing standards fail to reproduce this damage. This thesis aims to (1) elucidate the Ti-6Al-4V selective dissolution mechanism as functions of solution chemistry, electrode potential and temperature; (2) investigate the effects of adverse electrochemical conditions on additively manufactured (AM) titanium alloys and (3) apply machine learning to predict the Ti-6Al-4V dissolution state. We hypothesized that (1) cathodic activation and inflammatory species (H₂O₂) would degrade the Ti-6Al-4V oxide, promoting dissolution; (2) AM Ti-6Al-4V selective dissolution would occur …

Engineering Next-Generation Cardiovascular Therapies, Ryan Walker Barrs

All Dissertations

Cardiovascular diseases are the leading cause of death worldwide. Heart disease, in particular, accounted for 1 in every 5 deaths in the United States in 2021, representing a substantial public health burden that will require more effective treatment options to alleviate. Heart transplant surgery is currently the only option to completely restore cardiac function, but many patients die while waiting for a transplant due to a longstanding organ donor shortage. Thus, there is a dire need for accessible treatment options that can repair damaged hearts. Recent advances in tissue engineering and regenerative medicine have accelerated the development of therapies for …