Other Biomedical Engineering and Bioengineering Commons^™

Human Cardiovascular Responses To Simulated Partial Gravity And A Short Hypergravity Exposure, Qingguang Zhang

Theses and Dissertations--Biomedical Engineering

Orthostatic intolerance (OI), i.e., the inability to maintain stable arterial pressure during upright posture, is a major problem for astronauts after spaceflight. Therefore, one important goal of spaceflight-related research is the development of countermeasures to prevent post flight OI. Given the rarity and expense of spaceflight, countermeasure development requires ground-based simulations of partial gravity to induce appropriate orthostatic effects on the human body, and to test the efficacy of potential countermeasures.

To test the efficacy of upright lower body positive pressure (LBPP) as a model for simulating cardiovascular responses to lunar and Martian gravities on Earth, cardiovascular responses to upright …

Long Term Blood Oxygenation Membranes, Joseph V. Alexander

Theses and Dissertations--Biomedical Engineering

Hollow fiber membranes are widely used in blood oxygenators to remove carbon dioxide and add oxygen during cardiopulmonary bypass operations. These devices are now widely used off-label by physicians to perform extracorporeal blood oxygenation for patients with lung failure. Unfortunately, the hollow fiber membranes used in these devices fail prematurely due to blood plasma leakage and gas emboli formation.

This project formed ultrathin (~100nm) polymer coatings on polymer hollow fiber membranes. The coatings were intended to “block” existing pores on the exterior surfaces while permitting high gas fluxes. This coating is synthesized using surface imitated control radical polymerization.

The coating …

Characterization Of Closed Head Impact Injury In Rat, Yi Hua, Praveen Akula, Matthew Kelso, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

The closed head impact (CHI) rat models are commonly used for studying the traumatic brain injury. The impact parameters vary considerably among different laboratories, making the comparison of research findings difficult. In this work, numerical CHI experiments were conducted to investigate the sensitivities of intracranial responses to various impact parameters (e.g., impact depth, velocity, and position; impactor diameter, material, and shape). A three-dimensional finite element rat head model with anatomical details was subjected to impact loadings. Results revealed that impact depth and impactor shape were the two leading factors affecting intracranial responses.The influence of impactor diameter was region-specific and an …

Primary Cilia Mechanotransduction And Microtubule Stability In Mechanically Stretched Lung Adenocarcinoma Cells, Monika Rassi Radhika

Theses and Dissertations

The objective of this study is to investigate the role of microtubule based organelle, the primary cilia in lung adenocarcinoma by i) Quantifying the presence of primary cilia in several Non Small Cell Lung Cancer (NSCLC) cell lines in response to mechanical stimuli, ii) Attempting to determine the role of primary cilia in cell migration, iii) Investigating the effects of Paclitaxel(Taxol) resistance in lung cancer cells, iv) Analyzing the response of lung cancer cells to Smoothened Inhibitors and v) Determining the effects of Transforming Growth Factor Beta-1(TGF-β1) induced Epithelial to Mesenchymal Transition(EMT) in lung cancer cells. To ascertain the effects …

A Highly Adaptive And Cost Effective Second Generation Incubator (Sgi) Towards Educational, Research And Clinical Processes, Yassir H. Al-Sayagh

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Today´s rising demand for more reliable and affordable alternatives to organ transplant has led to a growing market for in vitro tissue culture systems. The main objective of tissue engineering as a whole is to employ human tissue equivalents for commercial use. The state-of-the-art processes for producing these so called tissue models are still very expensive, difficult to produce and time-consuming.

To engineer tissues, in vitro, a three-dimensional support structure commonly termed scaffold is needed. Stem cells are then added to the scaffold. In order for tissue to materialize, the scaffold and the cells must be incubated (cultured) at a …

Smooth Muscle Cell Organization In The Stem Region Of The Gracilis Collateral Circulation In Balb/C Mice, Laura Lenae Burckhardt

Biomedical Engineering

Of the approximately 8 million Americans who suffer from ischemic peripheral arterial occlusive disease (PAOD), many present with intermittent claudication, or pain associated with exercise. Impaired vasodilation of resistance vessels is a potential explanation for this symptom. Occluded arteries can lead to increased flow through collateral vessels, which function as natural bypasses around the obstruction. This increase in blood flow and resulting shear stress can cause outward remodeling, or arteriogenesis, which improves the efficacy of collaterals. However, following femoral artery ligation in a mouse model of chronic ischemia, vasodilation in the stem region of collateral vessels is impaired at day …

The Effect Of Artery Bifurcation Angles On Fluid Flow And Wall Shear Stress In The Middle Cerebral Artery, Zachary Ramey Jones

Master's Theses

Saccular aneurysms are the abnormal plastic deformation of veins and arteries that can lead to lethal thrombus genesis or internal hemorrhaging. Medication and surgery greatly reduce the mortality rates, but treatment is limited by predicting who will develop aneurysms. A common location for saccular aneurysm genesis is at the main middle cerebral artery (MCA) bifurcation. The main MCA bifurcation is comprised of the M1 MCA segment, parent artery, and two M2 segments, daughter arteries. Studies have found that the lateral angle (LA) ratio of the MCA bifurcation is correlated with aneurysm formation. The LA ratio is defined as the angle …

Design, Characterization And Application Of A Multiple Input Stethoscope Apparatus, Spencer Geng Wong

Master's Theses

For this project, the design, implementation, characterization, calibration and possible applications of a multiple transducer stethoscope apparatus were investigated. The multi-transducer sensor array design consists of five standard stethoscope diaphragms mounted to a rigid frame for a-priori knowledge of their relative spatial locations in the x-y plane, with compliant z-direction positioning to ensure good contact and pressure against the subject’s skin for reliable acoustic coupling. When this apparatus is properly placed on the body, it can digitally capture the same important body sounds investigated with standard acoustic stethoscopes; especially heart sounds. Acoustic signal inputs from each diaphragm are converted to …

Nerve Fiber Diameter Measurements Using Hematoxylin And Eosin Staining And Brightfield Microscopy To Assess The Novel Method Of Characterizing Peripheral Nerve Fiber Distributions By Group Delay, Jorge Arturo Vazquez

Master's Theses

Peripheral neuropathies are a set of common diseases that affect the peripheral nervous system, causing damage to vital connections between various parts of the body and the brain and spinal cord. Different clinical conditions are known to selectively impact various size nerve fibers, which often makes it difficult to diagnose which peripheral neuropathy a patient might have. The nerve conduction velocity diagnostic test provides clinically useful information in the diagnosis of some peripheral neuropathies. This method is advantageous because it tends to be minimally invasive yet it provides valuable diagnostic information. However, this test does not determine characteristics of peripheral …

Experimental And Numerical Investigation Of The Mechanism Of Blast Wave Transmission Through A Surrogate Head, Yi Hua, Praveen Akula, Linxia Gu, Jeff Berg, Carl A. Nelson

Department of Mechanical and Materials Engineering: Faculty Publications

This work is to develop an experiment-validated numerical model to elucidate the wave transmission mechanisms through a surrogate head under blast loading. Repeated shock tube tests were conducted on a surrogate head, i.e., water-filled polycarbonate shell. Surface strain on the skull simulant and pressure inside the brain simulant were recorded at multiple locations. A numerical model was developed to capture the shock wave propagation within the shock tube and the fluid-structure interaction between the shock wave and the surrogate head. The obtained numerical results were compared with the experimental measurements. The experiment-validated numerical model was then used to further understand …

Mathematically Modeling Fetal Electrocardiograms, Samuel Estes, Kiersten Utsey, Erick Kalobwe

Pursuit - The Journal of Undergraduate Research at The University of Tennessee

Abstract

Some of the most common and fatal birth defects are those related to the heart. In adults, possible heart conditions are often identified through the use of an electrocardiogram (ECG). However, due to the presence of other signals and noise in the recording, fetal electrocardiography has not yet proven effective in diagnosing these defects. This paper develops a mathematical model of three-dimensional heart vector trajectories, which was used to generate synthetic maternal and fetal ECG signals. The dipole model is a useful simplification in which the electrical activity of the heart is viewed as a single time-varying vector originating …

Developent Of A Phospholipid Encapsulation Process For Quantum Dots To Be Used In Biologic Applications, Logan Grimes

Master's Theses

The American Cancer Society predicts that 1,665,540 people will be diagnosed with cancer, and 585,720 people will die from cancer in 2014. One of the most common types of cancer in the United States is skin cancer. Melanoma alone is predicted to account for 10,000 of the cancer related deaths in 2014. As a highly mobile and aggressive form of cancer, melanoma is difficult to fight once it has metastasized through the body. Early detection in such varieties of cancer is critical in improving survival rates in afflicted patients. Present methods of detection rely on visual examination of suspicious regions …

Team Omnimouse, Derek J. Halman, Josh B. Porter, Steven A. Silver, Ian S. Stemper

Computer Engineering

INFORMATION, DATA, FIGURES AND DRAWINGS EMBODIED IN THIS DOCUMENT ARE STRICTLY CONFIDENTIAL AND ARE SUPPLIED ON THE UNDERSTANDING THAT THEY WILL NOT BE DISCLOSED TO THIRD PARTIES WITHOUT THE PRIOR WRITTEN CONSENT OF QUALITY OF LIFE PLUS.

Developing Defined And Scalable 3d Culture Systems For Culturing Human Pluripotent Stem Cells At High Densities, Yuguo Lei, Daeun Jeong, Jifang Xiao, David V. Schaffer

Department of Chemical and Biomolecular Engineering: Faculty Publications

Human pluripotent stem cells (hPSCs)—including embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs)—are very promising candidates for cell therapies, tissue engineering, high throughput pharmacology screens, and toxicity testing. These applications require large numbers of high quality cells; however, scalable production of human pluripotent stem cells and their derivatives at a high density and under well-defined conditions has been a challenge. We recently reported a simple, efficient, fully defined, scalable, and good manufacturing practice (GMP) compatible 3D culture system based on a thermoreversible hydrogel for hPSC expansion and differentiation. Here, we describe additional design rationale and characterization of this …

A Study Of Ciliary Beating In Chlamydomonas, Xin Li

Renée Crown University Honors Thesis Projects - All

The goal of this research is to understand how a unicellular green alga, Chlamydomonas-reinhardtii, responds to red light (670nm) and sound waves, by monitoring the beating frequency of its two cilia, which control cell motility. Ciliary beating frequency (BF) is proportional to the production of ATP, mainly generated by photosynthesis. A photosynthesis inhibitor, 3-(3-, 4-dichlorophenyl)-1, 1-dimethylurea (DCMU) decreases ATP production by photosynthesis. I used DCMU as a tool to analyze the red light effect on BF.

In the process of studying the effect of red light, I unexpectedly discovered experimental conditions for unstable ciliary beating (as shown in the video). …

Validation Of A Diffuse Reflectance Microendoscope With Polydimethylsiloxane Optical Phantoms And Monte Carlo Modeling, Gage Joseph Greening

Biomedical Engineering Undergraduate Honors Theses

We have introduced a method for creating thin-film PDMS optical phantoms that can be used to validate a bench-top optical device called a Diffuse Reflectance Microendoscope (DRME). The DRME is acquires data on cell surface morphology and sub-surface diffuse reflectance, which may provide clinicians with the tools to diagnose oral cancer at earlier stages. Phantoms were created with PDMS. Optical properties of the phantoms were controlled with the addition of nigrosin and titanium dioxide. Depth of phantoms was controlled by a spin coater. The DRME was built with a combination of filters and dichroic mirrors to separate electromagnetic radiation in …

Poly (Glycerol Sebacate) Nanofibers And Nanofilms For Tissue Engineering Application, Stephanie Grace Cone

Biomedical Engineering Undergraduate Honors Theses

In the field of tissue engineering, the development of biodegradable scaffolds that provide both structure and functionality is a major challenge. The use of biological implants, such as decellularized tissues, provides a complete matrix with full tissue functionality, however, problems with immunogenicity often arise when implants from other organisms are used in treatments. As such, there are many benefits to the use of polymeric constructs in tissue engineering. The ability to customize the material, design, and size of an implant provides opportunities for increased structural support and controlled rates of biodegradation. The selection of polymers for tissue engineering applications requires …

Classification And Quantification Of Phenotypic Characteristics Of Normal And Dysplastic Oral Cells, Jackson W. Boice

Biomedical Engineering Undergraduate Honors Theses

Introduction Oral cancer accounts for 2.5% of all cancer cases in the United States. The 5 year survival rate or stage 1 or localized oral cancer is 82%, and the survival rate of unstaged oral cancer is only 50%; therefore, early diagnosis is key. Current clinical practices for determining malignancy of tissue include physical examination and surgical biopsy, which can be plagued by high variability between observers and are invasive for the patient. Proflavine intercalates between base pairs of nucleic acids and has excitation and emission peaks at 455 (+/- 20) nm and 515 nm respectively; therefore, it can be …

Optimizing In Vitro Extracellular Matrix Production Using Polymer Scaffolds With Targeted Pore Size, Addison M. Walker

Biomedical Engineering Undergraduate Honors Theses

Extracellular matrix (ECM) has been shown to provide the framework needed for healthy tissue to grow after experiencing an injury. The optimization of growing ECM is a pressing concern in the tissue regeneration field. From prior research, an in vitro approach for harvesting ECM has been created using polyurethane (PU) foams seeded with cells. Our approach aimed at discovering if the pore size of the foams increased the amount of recovered ECM. Scaffolds of targeted pore size were created by separating sugar granules using a sieve, packing the sugar into a cylindrical mold, then pouring PU over the sugar. Three …

How Imbalanced Excitation And Inhibition May Cause Low Entropy Brain Dynamics, Qusay Redwan Alfaori

Biomedical Engineering Undergraduate Honors Theses

To study the effect of the imbalance of excitation and inhibition neurons on brain entropy using a computer model of a brain. The brain model will be composed of a neural network and entropy of the neural network will be measured quantitatively. Entropy in this context quantifies how many different patterns of activated neurons the brain can create. Imbalance between excitation and inhibition neurons causes the brain to malfunction, which can be an underlying cause of autism.