Biomedical Engineering and Bioengineering Commons^™

Transcriptional Regulation Of Arrhythmia: From Mouse To Human, Yun Qiao

McKelvey School of Engineering Graduate Student Theses & Dissertations

In the last two decades, our understanding of cardiac arrhythmias has been accelerated immensely by the development of genetically engineered animals. Transgenic and knockout mice have been the “gold standard” platforms for delineating disease mechanisms. Much of our understanding of the pathogenesis of atrial and ventricular arrhythmias is gained from mouse models that alter the expression of specific ion channels or other proteins. However, cardiac arrhythmias such as atrial fibrillation are heterogeneous diseases with numerous distinct conditions that could not be explained exclusively by the disruption of ionic currents. Increasing evidence suggests disruption of signaling pathways in the pathogenesis of …

Design & Delivery Of Automated Winston-Lutz Test For Isocentric & Off-Axis Delivery Stability Utilizing Truebeam Developer Mode & Electronic Portal Imaging Device, Mahmoud Mohammad Yaqoub

UNLV Theses, Dissertations, Professional Papers, and Capstones

The uncertainties in treatment delivery cannot be ignored in radiation therapy. Thus, the quality assurance QA tests are very important task of the medical physicist in clinical practice. Assuring the coincidence between the mechanical isocenter of the Linear Accelerator (LINAC) and its radiation beams isocenter is one of the most important qualities need to be tested, and the Winston Lust (WL) test is the

most popular technique to perform this task, especially for the treatment modalities which need high precision in beam delivery such as the stereotactic radiosurgery/stereotactic body radiotherapy (SRS/SBRT). The linear accelerator-based SRS/SBRT is a well-established method in …

Poly- L -Lactic Acid- Co-Poly(Pentadecalactone) Electrospun Fibers Result In Greater Neurite Outgrowth Of Chick Dorsal Root Ganglia In Vitro Compared To Poly- L -Lactic Acid Fibers, Alexis M. Ziemba, Keith P. Lane, Ignacio M. San Segundo, Anthony R. D'Amato, Andrew K. Mason, Ryan J. Sexton, Hubert Casajus, Richard A. Gross, David T. Corr, Ryan J. Gilbert

Chemical and Biochemical Engineering Faculty Research & Creative Works

Electro spun poly-l-lactic acid (PLLA) fiber scaffolds are used to direct axonal extension in neural engineering models. We aimed to improve the efficacy of these fibers in promoting neurite outgrowth by altering surface topography and reducing fiber elastic modulus through the incorporation of a compatibilized blend, poly-l-lactic acid-poly(pentadecalactone) (PLLA-PPDL) into the solution prior to electrospinning. PLLA+PLLA-PPDL fibers had a larger diameter, increased surface nano topography, and lower glass transition temperature than PLLA fibers but had similar mechanical properties. Increases in neurite outgrowth on PLLA+PLLA-PPDL fibers were observed, potentially due to the significantly increased diameter and surface coverage with nano topography. …

Thermal Fluid Models Of A Hydrogel Delivery System For Pancreatic Cancer Treatment, Nesrine Bouhrira

Theses and Dissertations

Pancreatic cancer is one of the most devastating cancers with low survival rates. This disease is difficult to detect due to the pancreas's location deep within the body. Therefore, diagnoses are often made in the later stages, making treatment options more limited and difficult. It has been hypothesized that direct injection into the tumor would enhance drug effectivenes. Therefore, we examined the use of endoscopic ultrasound (EUS) combined with a fine needle injection to deliver a drug-eluding thermosensitive hydrogel directly into the tumor. Unfortunately normal body temperatures surrounding the EUS can warm the hydrogel drug combination beyond its phase transition …

Assessment Of Risk In Preterm Infants Using Point Process And Machine Learning Approaches, Venkata Naga Sai Apurupa Amperayani

Electrical Engineering Theses

Preemies, infants who are born too soon, have a higher incidence of Life-Threatening Events (LTE’s) such as apnea (cessation of breathing), bradycardia (slowing of heart rate) and hypoxemia (oxygen desaturation) also termed as ABD (Apnea, Bradycardia, and Desaturation) events. Clinicians at Neonatal Intensive Care Units (NICU) are facing the demanding task of assessing the risk of infants based on their physiological signals. The aim of this thesis is to develop a risk stratification algorithm using a machine-learning framework with the features related to pathological fluctuations derived from point process model that will be embedded into the current physiological recording system …

A Study Of Acoustically Activated Nanodroplets, Songita Choudhury

Theses & Dissertations

Current treatment of acute myocardial infarction (AMI), which is the main pathophysiological event leading to death in the United States, has advanced considerably with the introduction of emergent percutaneous interventions, but there remains an urgent need for novel techniques to rapidly and accurately detect infarcted or ischemic tissue that results from AMI. Ultrasound contrast agents, also known as microbubbles (MB), have become commonplace in echocardiography. However, MBs are purely intravascular tracers and unable to cross endothelial barriers due to size. The limitations of MBs, namely size and short circulation times within the human body, led to the development of phase-change …

Determinants Of Multi-Scale Patterning In Growth Plate Cartilage, Alek Erickson

Theses & Dissertations

ABSTRACT

Functional architectures of complex adaptive systems emerge by dynamic control over properties of individual components. During skeletal development, growth plate cartilage matches bone geometries to body plan requisites by spatiotemporally regulating chondrocyte actions. Bone growth potential is managed by the proximodistal patterning of chondrocyte populations into differentiation zones, while growth vectors are specified by the unique columnar arrangement of clonal groups. Chondrocyte organization at both tissue and cell levels is influenced by a cartilage-wide communication network that relies on zone-specific release and interpretation of paracrine signals. Despite genetic characterization of signaling interactions necessary for cartilage maturation, the regulatory mechanisms …

Design Of A Homeopathic Solution For Chronic Cough, Jacob Ziemke

Senior Honors Projects, 2010-2019

Chronic cough is most commonly defined as a cough that persists for more than eight weeks and is estimated to affect more than 30 million people in the United States at any given time. Diseases contributing to the onset of chronic cough include asthma, pulmonary fibrosis, lung cancer, postnasal drip, gastroesophageal reflux disease (GERD), and bronchitis, and may include lifestyle choices such as smoking. For those who seek medical advice, pharmaceuticals and speech therapy are two common methods of combating chronic cough but serve to mask the symptoms rather than treat the problem; frequently, chronic cough is misdiagnosed or cannot …

Verification And Validation Of Forces From Hippotherapy Rein Simulator, Sonia Sanchez

Graduate Theses - Biology & Biomedical Engineering

The thesis describes the redevelopment, testing, and validation of a rein training device intended to help riders learn to guide a horse during hippotherapy sessions. The thesis aims to validate and verify that the forces read by the redeveloped rein simulator were operant within ± 150 grams of the actual weight applied, as well as to investigate the effect of temperature on the system. The simulator focuses on the use of the English style of riding that uses direct force from the reins to guide a horse to turn or stop. Data was collected by hanging weights from the load …

Effect Of Silk-Based Hydrogel Topography On Intestinal Epithelial Cell Morphology And Wound Healing In Vitro, Marisa E. Boch

University Scholar Projects

Recent advances in the field of biomaterials have suggested that cells cultured on substrates resembling the native tissue mechanical properties, matrix and growth factor composition, and topography can adopt phenotypes that more closely resemble the in vivo tissue compared to cells cultured on non-mimetic constructs. Understanding the effect of culture substrate on in vitro tissue formation is important for bioengineering applications that include mechanistic studies of healthy tissue function and development of disease models. In this work, Caco-2 adenocarcinoma cells were seeded on flat and crypt-like topographies of 3D-printed cytocompatible hydrogels derived from silk fibroin protein. Silk hydrogels were selected …

3d Printed Force Transducers For In-Vitro Mitral Valve Chordae Tendineae Force Measurements, Hayley Chandler

Biomedical Engineering Undergraduate Honors Theses

Mitral valve surgery is incredibly prevalent in the United States with more than 40,000 mitral valve surgical procedures annually. Improving the imaging techniques used to diagnose these cases requires validation of 3D models through experimental data such as mechanical properties of the tissue. An essential part of this process for the mitral valve is measuring the force experienced by chordae tendineae. This has been achieved with brass force transducers but using a 3D printed design can have many benefits. In this study, 3D printed miniature c-shaped force transducers comparable to previous metal models were designed and created using Solidworks 2016. …

Investigation Of Functional Connectivity And Neurovascular Coupling In Different Vigilance / Breath-Hold States Of The Brain From Simultaneous Eeg-Fnirs Measurements, Olajide Babawale

Bioengineering Dissertations - Archive

Functional connectivity and neurovascular coupling are important phenomena that occur in the brain. Functional connectivity is the study of functional brain networks and their characteristics. While neurovascular coupling is the relationship or link between neuronal activity and corresponding cerebral blood flow in the brain. Up until now, both functional connectivity and neurovascular coupling have not been studied in different vigilance states of the brain from wakeful rest state to sleep state, using simultaneous EEG-fNIRS measurements. Also, the neurovascular coupling in different states of breath-holding has not been studied using simultaneous EEG-fNIRS measurements Therefore, my doctoral research utilized a whole-head simultaneous …

Creep Response And Adhesion Dynamics Of Glioblastoma Multiforme Cells During Migration In Confined Environment, Ishan Kamal Khan

Bioengineering Dissertations - Archive

Glioblastoma multiforme (GBM) is the most common and malignant form of primary brain tumor. One of the major challenges facing the treatment of GBM tumors is the detachment and subsequent migration of peripheral cells. Migration of GBM cells take place in mechanically distinct confined microenvironment along the borders of white matter tracts. Studies using microfluidic devices mimicking the in-vivo microenvironment have shown that the migration characteristics are significantly altered with the change in kinematic state of the migrating cell. Several studies on different types of cells have consistently shown that a cancerous cell is more compliant than a normal cell …

Investigation Of 1064-Nm Laser Fluence Within Tissue Phantoms And Its In Vivo Effects On Human Brain Networks, Hasan Parvez

Bioengineering Theses - Archive

For the past few decades there has been an increasing interest in the usage of near infrared (NIR) laser in the medical optics field. This is due to a number of studies conducted on different animal models utilizing NIR laser, which was reported to provide improvement in such cognitive functions as memory, decision making, and executive functions. The NIR laser produces no adverse effects in the human tissue, having a potential for treating different neurological disorders. However, there is limited knowledge related to the underlying mechanism of photon interaction with the human tissue. In this thesis, I tried to address …

Designing A Synthetic Spider Silk-Based Coating For Urinary Catheters To Reduce The Risk Of Cautis, Alexander Cook

Undergraduate Honors Capstone Projects

Urinary and Intravenous (IV) catheters are two of the most commonly used medical devices for administering vital drugs and obtaining diagnostic samples from patients. Unfortunately, hospital acquired infections (HAIs) occur at alarming rates due to catheter usage. The aim of this project was to design a urinary catheter that would decrease the occurrence of these infections with a catheter coating that utilizes the antimicrobial properties of synthetic spider silk in combination with the antiseptic chlorhexidine. This synthetic spider silk catheter will introduce a novel approach to catheterization in the medical industry.

Designing A Synthetic Spider Silk Based Coating For Urinary Catheters To Reduce The Risk Of Cautis, Tess Marie Armbrust

Undergraduate Honors Capstone Projects

Catheter associated urinary tract infections (CAUTis) are a leading cause of morbidity and mortality in patients with life-threatening conditions. Foley catheters are the most common catheter used when a patient requires hospitalization but can become burdened with microbes which lead to CAUTis, the most common source of hospital acquired infection (HAI). The attached bacteria can form biofilms on the catheter which are difficult to treat using oral antibiotics and can lead to chronic infections. Synthetic spider silk as a catheter coating shows great promise because of demonstrated strength, biocompatibility, and antimicrobial properties. In addition, the antiseptic chlorhexidine can enhance the …

Investigations Of Polyhydroxyalkanoate Secretion And Production Using Sustainable Carbon Sources, Chad L. Nielsen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Polyhydroxyalkanoates (PHAs) are a type of biologically-produced plastic known for their biocompatibility and biodegradability. They have the potential to replace petroleum-based plastics as an environmentally-friendly alternative. This is beneficial because the release of plastics into environments such as the ocean and the buildup of plastics in landfills are major concerns facing society today. Currently, however, PHAs are significantly more expensive than their petroleum-based counterparts. This is largely due to the cost of carbon sources and of extracting the bioplastics from bacteria. The goal of these studies was to examine replacing traditional carbon sources used in PHA production like sugar and …

Quantification Of Tumor-Associated Macrophages Following Immunomodulation Therapy In A Murine Allograft Model Of Colorectal Carcinoma, Caroline Spainhour

Biomedical Engineering Undergraduate Honors Theses

Colorectal Carcinoma (CRC) is one of the deadliest cancers in the world, with 150,000 new cases annually in the United States. Traditional treatments include chemotherapy and invasive surgery; however, research has shown that only 25% of patients that undergo traditional treatment have a positive result. Immunotherapy is an emerging form of cancer treatment that utilizes the patients’immune system to fight cancer cells by targeting inflammation, which plays a large role in the proliferation and metastasis of cancer cells.

Tumor-associated macrophages (TAMs) are immune cells that affect the inflammatory microenvironment of tumors. TAMs are M1 in the early stages of tumors, …

Role Of Local Renin-Angiotensin System In Altering Valve Interstitial Cell Phenotype, Sophia Scalise

Biomedical Engineering Undergraduate Honors Theses

Hypertension is a disorder prevalent in adults around the world and is a common attributable cause of heart disease and mortality [1]. Calcification is much more common in the aortic valve than the other three heart valves [2]. Aortic valve interstitial cells (VICs), the principal cell type found in the human aortic valve, have been linked to disease development when they change in phenotype to become osteoblast like cells [3]. The phenotypes of these cells play a role in the development of calcification in the aortic valves [4].

Angiotensin II is a hormone in the body that has been implicated …

Antibacterial Properties Of A Cationic Imidazolium-Containing Poly(Ionic Liquid), Kaitlyn P. Brickey

Biomedical Engineering Undergraduate Honors Theses

Poly(ionic liquids), or PILs, have been shown to have a number of biological applications as ligands, drug delivery vehicles, and nonviral DNA delivery mechanisms. Additionally, PILs have been proven to be efficient antibacterials. Imidazolium-containing PILs have promising results in antibacterial studies, but relating to their chain and charge density, only the effects of mono- & bis-imidazolium PILs have been sufficiently described in literature. The work detailed in this thesis aimed to further existing research on the effect of chain density by controlling the UV-initiator immobilization time. The effects of chain density were investigated by grafting poly(vinylimidazolium chloride) onto SiO_{2 …}

Regeneration Of The Ventricular Endocardium Within Acellular Whole Rabbit Hearts Using A Layer-By-Layer Seeding Method, Clayton Lewis Compton

All Theses

In the United States, 1 out of every 9 death certificates in 2013 referenced heart failure.1 Despite the outstanding need of treatment options for heart failure, heart transplantation remains the optimal treatment method. However, there is a severe shortage of donor hearts available for transplantation.2 Other available treatment options are not ideal because they do not fully restore function and are associated with creating other complications.3 Thus, there is a need for developing a living tissue engineered whole heart for transplantation to provide an alternative option for patients on the waitlist to receive a donor heart.

Our solution is to …

Experimental And Model-Based Terahertz Imaging And Spectroscopy For Mice, Human, And Phantom Breast Cancer Tissues, Tyler Bowman

Graduate Theses and Dissertations

The goal of this work is to investigate terahertz technology for assessing the surgical margins of breast tumors through electromagnetic modeling and terahertz experiments. The measurements were conducted using a pulsed terahertz system that provides time and frequency domain signals. Three types of breast tissues were investigated in this work. The first was formalin-fixed, paraffin-embedded tissues from human infiltrating ductal and lobular carcinomas. The second was human tumors excised within 24-hours of lumpectomy or mastectomy surgeries. The third was xenograft and transgenic mice breast cancer tumors grown in a controlled laboratory environment to achieve more data for statistical analysis.

Experimental …

Computational Fluid Dynamics Model For Air Velocity Through A Poultry Transport Trailer In A Holding Shed, Christian Heymsfield

Graduate Theses and Dissertations

Broiler production in Arkansas was valued at over $3.6 billion in 2013 (University of Arkansas Division of Agriculture Cooperative Extension Service). Consequently, improvement in any phase of the production process can have significant economic impact and animal welfare implications. One area of concern for the poultry industry is thermal stress experienced by the birds after arrival at the processing plant and before they are taken in to be processed, during which time they are left to wait in holding sheds. Various cooling strategies exist to mitigate heat stress in holding sheds, but in most cases it is unlikely that they …

In-Vitro Simulation Of Acute Ischemic Stroke, Paolo Garcia

Biomedical Engineering Undergraduate Honors Theses

Acute ischemic stroke (AIS) is a condition that involves the occlusion of a blood vessel within the brain, effectively preventing the passage of oxygen and nutrients. AIS is highly prevalent in the United States, where nearly 795,000 strokes happen per year and 87% of those are ischemic. From a medical standpoint, the obstructing clot can be removed with the use of a stroke retrieval device. However, a need arises for testing the aforementioned devices on a patient’s specific vascular geometries in order to increase the likelihood of a successful procedure. Outlined is a process for developing a physical simulation of …

Development Of An In Vitro Platform For The Exploration Of Skeletal Muscle Cell Mechanobiology, Sydney Spradlin

Biomedical Engineering Undergraduate Honors Theses

Muscles have the natural ability to regenerate when damaged. This works to keep the body functioning, unless this ability is overwhelmed. Volumetric muscle loss (VML) occurs when a substantial amount of a muscles mass is lost. This leads to the development of scar tissue, and often a loss of function. In order to find a solution for this condition, in vitro models are needed to explore the mechanobiology of skeletal muscle cells. Two platforms were developed in this study, to explore 3 factors: orientation, strain, and supporting structure. One platform used fibronectin stamped lanes on PDMS to encourage cell growth …

Pressure Acquisition System For In Vitro Mitral Valve Analysis, Laura Peck

Biomedical Engineering Undergraduate Honors Theses

In vitro testing of the mitral valve chordae tendineae is utilized to aid in the understanding of the stresses that occur in vivo and improve upon surgical solutions that exist for mitral valve repair. This project aimed to design the water control system for a left heart simulation chamber, as well as the pressure acquisition inside the chamber. A solenoid valve was utilized to control the water supply to the tank and was powered utilizing National Instruments software. National Instruments hardware and software was also used with the pressure transducer in order to obtain pressure readings from the chamber. The …

Comparison Of Varying Tissue Freezing Methods On Murine Colonic Tissue, James Hughes

Biomedical Engineering Undergraduate Honors Theses

Histology often requires a tissue specimen to be embedded so that it may be sectioned, stained, and mounted on a microscope slide for viewing. One common method of tissue embedding for rapid histology is freezing, since freezing allows tissue to be stored without the need for fixing. Frozen tissue is often embedded in a medium such as Optimal Cutting Temperature (OCT) compound so that it can be sectioned using a cryostat. However, factors such as ice-crystal formation during the freezing process can cause damage to the tissue. As such, the protocol used to freeze the tissue can affect the quality …

Nutrient Limitation Of Algal Growth In Fishery Lakes, Madeline Ludwig

Biological and Agricultural Engineering Undergraduate Honors Theses

This study investigated the effect of nutrient addition on algal growth in three United States Forest Service lakes for fishery management in Arkansas. In fishery managed lakes, fertilization works by manipulating algae growth, a basal food resource in lakes, to promote the growth of the fish population. For the nutrient addition experiments, water was collected from each lake in cubitainers and spiked with nutrients; the treatments included the control, nitrogen (+N), phosphorus (+P), and nitrogen and phosphorus (+N +P). When algal growth was visually observed, a water sample was collected from each cubitainer and analyzed for chlorophyll-α. The results showed …

Optimizing Genetic Manipulation Of Methanogens Through Faster Cloning Techniques, Merrisa Jennings

Biological and Agricultural Engineering Undergraduate Honors Theses

Methanogenesis is the biological production of methane. Only anaerobic archaea known as methanogens are capable of such a metabolic feat. They have strict living conditions and substrate sources which determine their rate of metabolism. This is of particular importance from a greenhouse gas reduction perspective or biogas capturing perspective. One of the best ways to optimize methanogen methane production is via genetic manipulation. The current procedures are timely though, therefore a faster cloning processes should be developed. The objective of this study was to optimize a premade genetic transformation kit known as the Gibson Kit. The Gibson Kit was supposed …

In-Cage Surface Wetting System For Cooling Poultry In Transport, Ryan Clark

Biological and Agricultural Engineering Undergraduate Honors Theses

Abstract

Poultry health and mortality rates are important considerations in poultry production, as companies can minimize product loss and appeal to a consumer base whose concern for animal welfare continues to grow. Although animal welfare is a consideration for the entire poultry production process, this project focuses on the live-haul phase of the process, specifically during transport from grow houses to processing facilities. During the summer months, broiler chickens being transported can suffer from heat stress that can lead to death. This project consists of the designing and testing of an in-cage surface wetting system to minimize heat stress incidents …