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Theses/Dissertations

2014

Theses and Dissertations

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Articles 1 - 30 of 54

Full-Text Articles in Biomedical Engineering and Bioengineering

Experimental And Theoretical Studies Of Native And Engineered Vascular Tissue Mechanics, Boran Zhou Dec 2014

Experimental And Theoretical Studies Of Native And Engineered Vascular Tissue Mechanics, Boran Zhou

Theses and Dissertations

Background: Implantation of vascular grafts provides a means to restore blood flow in compromised regions of the circulatory system, and thus is used to treat a wide range of cardiovascular diseases. Despite significant advancements in autologous grafting strategies as well as the engineering of synthetic alternatives, mechanical, structural, and compositional incongruities between the graft and the host artery remain as contributing factors to graft failure. The typical failure modality manifests as proximal anastomotic intimal hyperplasia, which places restrictions on the host vessel size currently treated with grafting strategies (> 5 mm internal diameter). In order to improve long-term clinical outcomes, this ...


Development And Characterization Of An Autologous Whole Cell Breast Cancer Vaccine, Samantha Leigh Kurtz Dec 2014

Development And Characterization Of An Autologous Whole Cell Breast Cancer Vaccine, Samantha Leigh Kurtz

Theses and Dissertations

Approximately 40,000 women will die from breast cancer in the United States in 2014. About 90% of these deaths will be due to metastases, rather than the primary tumor and majority of metastases are due to the recurrence and progression of non-metastatic disease. Current adjuvant treatments, such as chemotherapy and radiation, have severe side effects and may result in overtreatment and drug resistance.

Since greater than 90% of patients are diagnosed between stages I-III and have minimal residual disease after treatment, there is an opportunity to treat patients with an autologous breast cancer vaccine. Autologous vaccines under development have ...


Development Of A Novel Device For The Perfusion Driven Decellularization Of Skeletal Muscle, Benjamin Kasukonis Dec 2014

Development Of A Novel Device For The Perfusion Driven Decellularization Of Skeletal Muscle, Benjamin Kasukonis

Theses and Dissertations

Decellularization of skeletal muscle is a process that removes cellular components of skeletal muscle tissue while leaving behind the intact extracellular matrix (ECM). Skeletal muscle ECM is currently being studied as a biologic scaffold for repairing volumetric muscle loss (VML) because the removal of cells greatly reduces the antigenicity of the donor tissue. Decellularization usually relies on passive diffusion of detergents, surfactants and/or osmotic solutions to strip cells from the ECM. However, passive diffusion alone is usually not sufficient for complete removal of cells from the interior of large pieces of skeletal muscle using detergents, such as sodium dodecyl ...


3d Differentiation Enhances The Efficiency Of Differentiation Of Human Induced Pluripotent Stem Cells To Insulin Producing Cells, Pavana Gururaj Rotti Dec 2014

3d Differentiation Enhances The Efficiency Of Differentiation Of Human Induced Pluripotent Stem Cells To Insulin Producing Cells, Pavana Gururaj Rotti

Theses and Dissertations

Type 1 Diabetes (T1D) is an autoimmune disorder in which the pancreatic β-cells are destroyed by the body's immune system. The reduced number of β-cells leads to inadequate insulin secretion and high glucose levels in the body. The requirement of insulin injection throughout life and lack of donors for islet transplantations has prompted a search for more accessible and available sources of insulin producing cells that can be transplanted in T1D patients. To that end, the discovery of induced pluripotent stem (iPS) cells has provided a potential source of precursors for cell therapy for T1D. iPS cells are reprogrammed ...


Adaptation And Validation Of An Analytical Localized Muscle Fatigue Model For Workplace Tasks, John Maurice Looft Dec 2014

Adaptation And Validation Of An Analytical Localized Muscle Fatigue Model For Workplace Tasks, John Maurice Looft

Theses and Dissertations

Muscle fatigue is universally experienced in daily life, from recreational physical activity to the workplace. However, our ability to estimate fatigue is limited. Several attempts have been made to mathematically model the effects of fatigue, such as how long a muscle contraction may be sustained, known as `endurance time.' However, these simple models of endurance time are limited to static contractions when the body is not moving, but muscles are contracted. This research aims to advance a previously proposed analytical model of muscle fatigue to represent complex tasks such as with rest intervals and dynamic contractions. Multiple methodologies were employed ...


The Dosimetric Impacts Of Gated Radiation Therapy And 4d Dose Calculation In Lung Cancer Patients, Ouided Rouabhi Dec 2014

The Dosimetric Impacts Of Gated Radiation Therapy And 4d Dose Calculation In Lung Cancer Patients, Ouided Rouabhi

Theses and Dissertations

With the introduction of four dimensional-computed tomography (4DCT), treatment centers are now better able to account for respiration-induced uncertainty in radiation therapy treatment planning for lung cancer. We examined two practices in which 4DCT is used in radiotherapy. Our first study investigated the dosimetric uncertainty in four-dimensional (4D) dose calculation using three temporal probability distributions: 1) uniform distribution, 2) sinusoidal distribution, and 3) patient-specific distribution derived from the respiratory trace. Four-dimensional dose was evaluated in nine lung cancer patients. First, dose was computed for each of 10 binned CTs using 4DCT and deformable image registration. Next, the 10 deformed doses ...


Development Of A Heart Rate Variability Measurement System Using Embedded Electronics, Naresh Kumar Velmurugan Dec 2014

Development Of A Heart Rate Variability Measurement System Using Embedded Electronics, Naresh Kumar Velmurugan

Theses and Dissertations

Recent advances in embedded electronics have a remarkable influence on the health care system. One of the most important applications is to monitor the health care of the patients at anytime and anyplace. In the last two decades, many researchers have focused mainly on heart rate variability (HRV) measurements. Patient's heart rate variability should be continuously monitored to help them in case of emergency. Under these circumstances, patients are required to have a HRV measuring kit for a constant observation.

The proposed project focuses on the development of a heart rate variability measurement system with the use of embedded ...


A Portable Impedance Biosensing System Based On A Laptop With Labview For Rapid Detection Of Avian Influenza Virus, Yixiang Wang Dec 2014

A Portable Impedance Biosensing System Based On A Laptop With Labview For Rapid Detection Of Avian Influenza Virus, Yixiang Wang

Theses and Dissertations

Avian Influenza Virus (AIV) H5N1 is a highly pathogenic virus found not only in birds but also in human. Rapid and sensitive detection method is needed to help prevent the spread of AIV H5N1. In this study, a portable impedance biosensing system based on a laptop with LabVIEW software was developed for detection of AIV H5N1. First, a virtual instrument was programmed with LabVIEW software to form a platform for impedance measurement, data processing and control. The audio card of a laptop was used as a function generator while a data acquisition card was used with the signal channels for ...


Role Of Sensation In Altered Phalanx Grip Force In Persons With Stroke, Leah R. Enders Dec 2014

Role Of Sensation In Altered Phalanx Grip Force In Persons With Stroke, Leah R. Enders

Theses and Dissertations

Many individuals experience hand impairment after stroke leading to decreased ability to perform daily living activities. Previous research studies have investigated how stroke survivors' pinch grip control differs from healthy individuals, even though many individuals can only grasp with power grip after stroke. Furthermore, many stroke survivors experience tactile sensory deficit in their paretic limb in addition to motor deficit. It is currently unknown how stroke induced tactile sensory deficit affects power grip force directional control, which is important in terms of preventing object slippage and power grip normal force generation. Additionally it is unknown if power grip could be ...


Biomechanical Joint Demands And Functional Outcomes During Manual Wheelchair Use In Pediatric Patients With Spinal Cord Injury, Christine M. Aurit Dec 2014

Biomechanical Joint Demands And Functional Outcomes During Manual Wheelchair Use In Pediatric Patients With Spinal Cord Injury, Christine M. Aurit

Theses and Dissertations

The biomechanical demands of the upper extremities (UEs) during pediatric manual wheelchair (MWC) use have not been fully explored. Children who use MWCs for mobility engage in a range of functional activities that may place large biomechanical demands on the UEs leading to a high risk on overuse injuries. This study aims to analyze the kinematics and kinetics of pediatric manual wheelchair use during propulsion, starting, stopping and weight relief tasks. Fourteen pediatric patients with spinal cord injury were recruited and data were collected using a 14-camera Vicon MX motion analysis system (Oxford Metric Group, Oxford, UK) and a SmartWheel ...


An Optogenetic Brain-Machine Interface For Spatiotemporal Neuromodulation, Ryan Andrew Baumgartner Dec 2014

An Optogenetic Brain-Machine Interface For Spatiotemporal Neuromodulation, Ryan Andrew Baumgartner

Theses and Dissertations

Direct neural stimulation has recently become a standard therapy for neurological disorders such as Parkinson's Disease, Essential Tremors, and Dystonia. Currently, deep brain electro-stimulation and neuro-pharmaceutical treatments are the dominant therapeutic options available to the public. As our understanding of brain function and neurological diseases improves, we are able to develop more advanced neuromodulation techniques. These methods could become viable treatment solutions for treating brain dysfunction. Optogenetics, first introduced by a research team led by Karl Deisseroth at Stanford University, has proved to be a versatile technique with remarkable potential to be used in treatments for brain disorders, dysfunction ...


A Three-Dimensional In Vitromodel Of Atherogenesis, Pin Hsuan Chang Aug 2014

A Three-Dimensional In Vitromodel Of Atherogenesis, Pin Hsuan Chang

Theses and Dissertations

Atherosclerosis is the narrowing of arteries caused by accumulation of cholesterol, calcium and other cellular debris in the inner arterial wall. While extensive studies have been focusing on the inflammatory mechanisms of the disease, pathological and experimental evidence has shown that regions of disturbed flow are susceptible to the atherogenesis. To further understand the relationship between hemodynamics and atherogenesis, this research aims to generate a dynamic, 3D in vitro model of atherogenesis. This will allow for the investigation of specific cellular and molecular mechanisms of plaque formation that will pave the way for new therapies for the disease. A novel ...


Developing A Bioreactor For Biaxial Mechanical Testing And Conditioning Of Vascular Tissue, Steve Marcous Aug 2014

Developing A Bioreactor For Biaxial Mechanical Testing And Conditioning Of Vascular Tissue, Steve Marcous

Theses and Dissertations

Cardiovascular diseases are known to be one of the major causes of death around the world. One of the major causes of cardiovascular disease is arterial malfunction. Arteries malfunction when they experience chronic perturbations in their local environment above normal levels. Hence, we developed a bioreactor system in order to study the effect of chronic changes in the arterial global parameters (axial force, luminal pressure, and flow rate) on the behavior of local parameters (circumferential stress, axial stress, and flow induced shear stress). The bioreactor system was designed to (i) perform biaxial mechanical testing, (ii) incorporate, for the first time ...


Construction Of 3d Biomimetic Tissue Niches For Directing Pancreatic Lineage Differentiation Of Human Embryonic Stem Cells, Weiwei Wang Aug 2014

Construction Of 3d Biomimetic Tissue Niches For Directing Pancreatic Lineage Differentiation Of Human Embryonic Stem Cells, Weiwei Wang

Theses and Dissertations

The potential of human embryonic stem cells (hESCs) to differentiate into insulin producing beta cells offers great hope for cell-based therapy for diabetes treatment. However, in vitro pancreatic differentiation of hESCs remains challenging. In the past decade, most protocols for differentiating pancreatic cells have been focused on the use of signaling molecule cocktails on 2D substrates. Studies on embryonic development biology strongly suggest that extracellular matrix (ECM) plays a critical role on hESCs behavior. In this work, we first established a 3D collagen scaffold culture system for hESCs differentiating into definitive endoderm (DE), which is the first and most important ...


Self-Assembly Of Gold Nanosphere Dimers By Inertial Force, George Andrew Christopher Sakhel Aug 2014

Self-Assembly Of Gold Nanosphere Dimers By Inertial Force, George Andrew Christopher Sakhel

Theses and Dissertations

The morphology and composition of a nanoparticle (NP) play a critical role in determining the NP's properties and function. To date, researchers have created a myriad of NPs of different shapes, sizes, and compositions with interesting attributes and applications ushering a revolution in medicine, electronics, microscopy, and microfluidics.

In this study, gold (Au) nanosphere dimers (NSDs) have been synthesized through a novel self-assembly method. These particles were created from Au NPs mono-dispersed in aqueous solution via a process of centrifugation and capping agent replacement. Au NSDs consist of two Au NPs combined together with minimal gaps between them. Optical ...


A Novel Cell Based Assay For Mmp Inhibitor Screening, Pantrika Krisanarungson Aug 2014

A Novel Cell Based Assay For Mmp Inhibitor Screening, Pantrika Krisanarungson

Theses and Dissertations

Up to date, a plethora of protein based materials are used as implants to stimulate tissue regeneration or fillers to alleviate tissue or organ impairment. This includes glottal insufficiency, urinary bladder incontinence and especially in cosmetic industrial to improve facial contour. Once in vivo, protein-based materials are decomposed by cell secreted matrix metalloproteinases (MMP) and lose their volume within months. By introducing MMP inhibitor (MMPI), the extent of material degradation over time may be reduced. In this dissertation, the development of cell-based assay capable of identifying MMPI candidates for protein-based implant lifetime prolongation is described. To visualize the degradation, DQ-gelatin ...


Improving Golf Putt Performance With Statistical Learning Of Eeg Signals, Qing Guo Aug 2014

Improving Golf Putt Performance With Statistical Learning Of Eeg Signals, Qing Guo

Theses and Dissertations

In this thesis, a machine learning based method is proposed to predict the putt outcomes of golfers based on their electroencephalogram (EEG) data. The method can be used as a core building block of a brain-computer interface, which is designed to provide guidance to golf players based on their EEG patterns. The proposed method includes three steps. First, multi-channel 1-second EEG trials were extracted during golfers' preparation of putting. Second, different features are calculated such as correlation coefficient, power spectrum density and coherence, which are used as features for the classification algorithm. To predict golfers' performance, the support vector machine ...


Cryoimaging-Microscopy Implementation For 3d Optical Imaging, Mohammad Masoudimotlagh Aug 2014

Cryoimaging-Microscopy Implementation For 3d Optical Imaging, Mohammad Masoudimotlagh

Theses and Dissertations

The structures and biochemistry properties of biological tissues are mostly affected by diseases. The visualization of organ structure and biochemistry helps in early detection and progression monitoring of diseases.

Although, 2D imaging has traditionally been used to gain information from the tissue, it does not accurately represent many of the structures and functions. There currently exists a need for sensitive and specific methods to show detailed information about the structure of the tissue with high resolution and in 3D. The potential advantage of the high resolution 3D images is the ability to accurately probe structural and biochemical properties of the ...


Effect Of Junction Geometry On Monodispersed Microdroplet Generation In Microfluidic Aqueous Two-Phase Systems, Young Gyu Nam Aug 2014

Effect Of Junction Geometry On Monodispersed Microdroplet Generation In Microfluidic Aqueous Two-Phase Systems, Young Gyu Nam

Theses and Dissertations

Aqueous two-phase system (ATPS) consists of two immiscible water-based solutions of polymers, which can form phase partitioning. Dextran and polyethylene glycol I used in this thesis is the one of common components of aqueous two-phase system give a reliable and incompatible environment for purification of biomedical products and cellular macromolecules. Recently, ATPS have received increasing attention as a separation method in microfluidic device due to the advantages of biocompatibility, unlimited combination, and low interfacial tension. Hence, it became an important to discover researches related to ATPS microfluidic device.

Microdroplets produced in microfluidic device are a largely interesting phenomenon for various ...


Early Targeting Of Knee Osteoarthritis : Validation Of Computational Methods, Tyler Joseph Stockman Aug 2014

Early Targeting Of Knee Osteoarthritis : Validation Of Computational Methods, Tyler Joseph Stockman

Theses and Dissertations

Osteoarthritis (OA) is the most common type of arthritis, a disease in which inflammation and stiffness of the joints occur. This debilitating disease of the joints currently reigns as the most prevalent among the world's populations. Of particular interest to our group is the study of the biomechanical factors relating to knee OA. Studies have shown that knee OA is related to multiple biomechanical factors, all of which are complexly interrelated. These factors have been seen to produce varied effects on the structures of the knee. This work examines validation of a computational model implementing discrete element analysis, and ...


The Effect Of Arch Insoles On Tibial Rotation And Tibiofemoral Contact Stress, Saphia Fatima Waheed Aug 2014

The Effect Of Arch Insoles On Tibial Rotation And Tibiofemoral Contact Stress, Saphia Fatima Waheed

Theses and Dissertations

No abstract provided.


Impedance Biosensors For The Rapid Detection Of Viral And Bacterial Pathogens Using Avian Influenza Virus Subtypes H5n1 And H7n2 And Escherichia Coli O157:H7 As Model Targets, Jacob David Lum Aug 2014

Impedance Biosensors For The Rapid Detection Of Viral And Bacterial Pathogens Using Avian Influenza Virus Subtypes H5n1 And H7n2 And Escherichia Coli O157:H7 As Model Targets, Jacob David Lum

Theses and Dissertations

This research investigated impedance biosensors for the rapid detection of viral and bacterial pathogens using avian influenza virus (AIV) subtypes H5N1 and H7N2 and Escherichia coli O157:H7 as the model targets, which were chosen due to their impact on the agricultural and food industries. For the detection of AIV H7N2, a single stranded DNA aptamer was selected using systematic evolution of ligands by exponential enrichment (SELEX). The selected aptamer and a previously selected aptamer against AIV H5N1 were used in a microfluidics chip with an embedded interdigitated array microelectrode to fabricate an impedance biosensor for specific detection of AIV ...


Experimental Terahertz Imaging And Spectroscopy Of Ex-Vivo Breast Cancer Tissue, Tyler C. Bowman Aug 2014

Experimental Terahertz Imaging And Spectroscopy Of Ex-Vivo Breast Cancer Tissue, Tyler C. Bowman

Theses and Dissertations

This thesis presents experimental results of terahertz imaging and spectroscopy techniques to analyze excised breast cancer tissue. The pulsed terahertz system at the University of Arkansas was used to assess formalin-fixed, paraffin-embedded breast cancer tissue obtained from 22, 40, and 46 year old patients. The tissue for this research was sliced to relatively thin sections of 10 μm thick and mounted on glass slides. Terahertz reflection time and frequency domain images of the breast cancer tissue were then obtained and compared to histopathology slides from the same patient. Results showed good correlation between the reflection images and histopathology slides for ...


Examining The Feasibility Of Magnetic Source Mri By Studying Fmri Acquisition And Analysis Strategies, Leo Ai Jul 2014

Examining The Feasibility Of Magnetic Source Mri By Studying Fmri Acquisition And Analysis Strategies, Leo Ai

Theses and Dissertations

Magnetic source magnetic resonance imaging (msMRI) is an fMRI technique that has been under development for direct detection of neuronal magnetic fields to map brain activity and has been shown to be experimentally detectable using conventional means, but there is debate on the detection of the msMRI signal since it can be only a 0.2% change. Detection of its temporal characteristics has yet to be reported and may strengthen the case for msMRI detection. The temporal characteristics of the detected msMRI signal were examined in this work, but it was found that the sensitivity of conventional analysis techniques are ...


Design And Application Of Methods For Curating Genetic Variation Databases, Sean Stephen Ephraim Jul 2014

Design And Application Of Methods For Curating Genetic Variation Databases, Sean Stephen Ephraim

Theses and Dissertations

Cordova (Curated Online Reference Database Of Variation Annotations) is an out-of-the-box solution for building and maintaining an online database of genetic variations integrated with population study information and pathogenicity prediction results from popular algorithms. Our primary motivation for developing this system is to aid researchers and clinician-scientists in determining the clinical significance of genetic variations. To achieve this goal, Cordova provides an interface to review and manually or computationally curate genetic variation data as well as share it for clinical diagnostics and the advancement of research.


Development Of A Surgical Simulation Toolkit For Mitral Valve Repair Surgeries, Piyusha Sanjay Gade Jul 2014

Development Of A Surgical Simulation Toolkit For Mitral Valve Repair Surgeries, Piyusha Sanjay Gade

Theses and Dissertations

Heart valve disease is estimated to cost over a billion dollars in the Unites States annually and mitral valve disorders account for the largest portion of the disease with treatments involving valve repair and replacement (Iung et. al). It is estimated that an experienced surgeon can effectively repair 95 - 100 percent of mitral valve (MV) disorders but a recent study showed that the average rate of MV repair is 41 percent. The current paradigm in treatments include diagnostic imaging data to see the current state of the patient, empirical data from previous similar cases to evaluate the efficacy of prior ...


Preterm Birth: Prediction, Prevention, Care, Brandon Wesley Alleman May 2014

Preterm Birth: Prediction, Prevention, Care, Brandon Wesley Alleman

Theses and Dissertations

Preterm birth (PTB) is defined as birth before 37 weeks gestational age. PTB is a common outcome and one that may be increasing in prevalence with serious individual and public health implications both immediately and long term. While PTB is a pregnancy specific outcome it is more appropriately viewed as the culmination of risk factors present both before pregnancy and possibly in past generations. This thesis attempts to review the implications, risk factors and current prevention strategies directed at PTB while placing it in an intergenerational and life cycle context. Three novel investigations are presented and their consequences are discussed ...


Tht And Capillary Electrophoresis To Monitor The Effects Of Solutions Conditions On Amylin Aggregation, Michael May May 2014

Tht And Capillary Electrophoresis To Monitor The Effects Of Solutions Conditions On Amylin Aggregation, Michael May

Theses and Dissertations

Amylin (hIAPP) aggregates have been found in 90% of patients with type II diabetes at autopsy, and are suspected to play a role in the death of islet &beta-cells1. However, this aggregation process is not well understood. Here, we explore methods that utilize capillary electrophoresis (CE) as a means to better understand amylin's aggregation process.

We examined the effects of solutions conditions: agitation, pH, salt, and temperature on amylin aggregation using Thioflavin T, dot blots, and capillary electrophoresis. Thiofalvin T was used to predict the lag time to &beta-sheet formation. Our results indicated all variables with the exception ...


Understanding Mechanical Trade-Offs In Changing Centers Of Rotation For Reverse Shoulder Arthroplasty Design, Vijay Niels Permeswaran May 2014

Understanding Mechanical Trade-Offs In Changing Centers Of Rotation For Reverse Shoulder Arthroplasty Design, Vijay Niels Permeswaran

Theses and Dissertations

Though the literature contains many computational models studying RSA, very few utilize finite element analysis to study stresses in the implant and the surrounding bone. The introductions section shows that many parameters (center of rotation lateralization, center of rotation superior or inferior position, tilt of the cut glenoid surface, glenosphere shape design, glenosphere size, humeral design, notch severity, etc.) have been studied independently utilizing many different methods (finite element modeling and non-FE computational modeling). However, the introduction section also detailed the current limitations in modern modeling as well as many examples of the heights to which finite element modeling can ...


Interaction Of Blood Cells With The Vessel Wall In Thrombosis, Jessica Kay Hansen May 2014

Interaction Of Blood Cells With The Vessel Wall In Thrombosis, Jessica Kay Hansen

Theses and Dissertations

Thrombotic events such as stroke, myocardial infarction, or deep vein thrombosis can be life-threatening; therefore it is important to understand the mechanisms of thrombosis and its correlations with clinical risk factors. It is well known that red blood cells (RBCs) can influence hemostasis and thrombosis by affecting the viscosity and rheological properties of blood. Recent evidence suggests that RBCs may play a more central and active role in some models of experimental thrombosis by interacting directly with the endothelium. It is still unclear, however, if the interaction of RBCs with the endothelial surface is facilitated by other blood components. In ...