Biomedical Engineering and Bioengineering Commons^™

Development Of An Impedance-Controlled Hot Snare Polypectomy Device To Minimize Tissue Damage, Curtislee Thornton

Electronic Theses and Dissertations

This study explores the ability to measure the changing impedance, ex vivo, of a porcine colon sample while undergoing a high-frequency alternating current from an Olympus PSD-30 electrosurgical unit and stop the applied current before excessive tissue damage ensues. The causes of the thermal damage are first examined, followed by the construction and testing of the impedance-controlled feedback device. Perforation was observed to occur when the impedance of the tissue sample increased by 25% or more. Using this information, the device was tested for five power settings ranging from 10W-50W. In each trial, the feedback device stopped the applied current …

Rotary Pump Speed Modulation To Produce Pulsatile Flow And Ventricular Volume Unloading., Connor Joseph Smith

Electronic Theses and Dissertations

Background: Continuous-flow (CF) left ventricular assist devices (LVADs) have gained widespread clinical acceptance as a treatment option for advanced heart failure (HF); however, they have also been associated with an increased risk of adverse events, including gastrointestinal bleeding, aortic insufficiency, and hemorrhagic stroke. It has been hypothesized that the increase in adverse event incidence may be due in part to diminished vascular pulsatility and high shear stress when CF-LVADs are operated at fixed speeds. Previous studies have shown that pump speed modulation generates greater levels of pulsatility in rotary pumps than when operated at fixed speeds. The objective of this …

Design And Development Of A Multifunctional Surgical Device For Ground And Space-Based Surgical Applications., Brooke Elaine Barrow

Electronic Theses and Dissertations

With the possibility of longer ventures into space, NASA will face many new medical challenges. The ability to surgically treat trauma and other disorders in reduced gravity requires reliable wound access, containment, and visualization. In collaboration with Carnegie Mellon University, the University of Louisville is currently developing the AISS (Aqueous Immersion Surgical System) to increase efficiency and control of the operative field in space-based surgeries. Reliable wound access and containment is achieved by placing a transparent wound-isolation dome securely over the wound-site and pressurizing it with a saline solution. Leak-free trocars provide access ports for various surgical instruments. This system …

Development Of Low Frequency Electron Paramagnetic Resonance Methods And Instrumentation For Biological Applications, Laura A. Buchanan

Electronic Theses and Dissertations

EPR is a powerful biophysical tool that can be used to measure tumor physiology. With the addition of magnetic field gradients, the spectral properties of paramagnetic species can be mapped. To facilitate EPR imaging, methods and instrumentation at frequencies between 250 MHz and 1 GHz were developed.

At low spin concentrations, the rapid scan background signal is often many times larger than the EPR signal of interest. To help remove the background contribution, a data acquisition procedure that takes advantage of a cross-loop resonator and bipolar power supplies was developed at 250 MHz. In this procedure, two scans are collected. …

A Novel Approach To Assess Minimally Invasive Surgical Device Failure Utilizing Adverse Event Outcome Severity And Design Complexity., Marie K. Riggs

Electronic Theses and Dissertations

Medical device failure and misuse have the potential to cause serious injury and death. Given the intricate nature of the instruments utilized specifically in minimally invasive surgery (MIS), users and manufacturers of surgical devices share a responsibility in preventing user error and device failure. A novel approach was presented for the evaluation of minimally invasive device failures, which involved assessing the severity of adverse event outcomes associated with the failures modes and investigating aspects of the devices’ design that may contribute to failure. The goals of this research were to 1) characterize the design attributes, failure modes, and adverse events …

Design, Development, And Characterization Of Breathforce : A Respiratory Training System For Patients With Spinal Cord Injuries., Kevin L Tran

Electronic Theses and Dissertations

Pulmonary and cardiovascular dysfunction are consistently reported as the leading causes of morbidity and mortality among the 1,275,000 people who are living with chronic spinal cord injury (SCI) in the United States. Respiratory-cardiovascular complications from neurological disorders (primarily COPD and sleep apnea) are currently the number one cause of death and disability in the US.

The main goal of this project is to develop an inspiratory-expiratory training device for use in the rehabilitation of patients with respiratory motor and cardiovascular deficits that incorporates existing technologies and promotes successful training methodologies performed at the clinic and at home.

An embedded microprocessor …

An Automated Device To Increase Screening Throughput Of Zebrafish Larvae, Fuoad Saliou-Sulley

Electronic Theses and Dissertations

The use of the zebrafish as an animal model alternative to mammalian species has spawned research advancements in several medical fields. Since the zebrafish shares a high degree of sequence and functional homology with mammals, studies using this organism can provide in-depth insight into host response to disease and provide a platform for testing a range of treatment options. The optical transparency of zebrafish at early stages of development permits easy assessment of the effects of treatments, occurrence of tumors and other abnormal growth, disease progression, and immune response, to name only a few. These characteristics make it ideal for …

Biomechanical Testing Of An Exercise For Strengthening The Proximal Femur., Alyssa Osbourne

Electronic Theses and Dissertations

Based on the principles of cutting edge bone remodeling research, a unique therapeutic exercise device was designed specifically to improve bone quality at the most critical location of the proximal femur prone to fracture: the superior-lateral femoral neck where the fracture first initiates during a fall. The exercise/device is intended to work by inducing enough strain in the bone to stimulate the body’s natural bone remodeling mechanisms to increase bone density in the proximal femur and consequently prevent a fracture from arising if a fall to the side does occur.

In order to test the proposed exercise, experiments simulating the …

Development And Evaluation Of A Biocompatible Electroactive Sensor For Continuous Blood Pressure Measurement., Scott D. Cambron

Electronic Theses and Dissertations

Piezo-active composites have been implemented for sensing and transduction for decades. The 0-3 ceramic/polymer composite is one of the most common composite types used for sensing applications, owing to their tailorable properties of the two-phase composition, consisting of a three-dimensionally connected polymer/rubber matrix (inactive phase) with a dispersion of isolated piezo-ceramic particles (active phase). This thesis describes a method to develop novel biocompatible perivascular band comprised of a two-phase piezo-active composite to be fabricated using simple manufacturing processes. Biomaterials such as tissue scaffolds comprised of silk fibroin (SF) and chitosan (CS), and biocompatible soft rubbers will be implemented as the …

Development Of A Directional Bone Reaming System., Richard J Ackermann

Electronic Theses and Dissertations

Preparation of long bones such as the femur or tibia for placement of intramedullary devices for the treatment of fractures usually involves reaming with a series of central cutters driven by a drill-like device with a flexible shaft over a guide wire. The reamers sequentially enlarge the intramedullary canal into a tunnel of circular cross-section and a diameter appropriate for the procedure. The current technology is concentric, meaning that the system is self-centering within the original intramedullary canal and the expansion is symmetric with respect to the original centerline. A novel system for laterally deflecting the head of a 12mm …

Development Of Spectroscopic Methods For Dynamic Cellular Level Study Of Biochemical Kinetics And Disease Progression, Anna M. Sitarski

Electronic Theses and Dissertations

One of the current fundamental objectives in biomedical research is understanding molecular and cellular mechanisms of disease progression. Recent work in genetics support the stochastic nature of disease progression on the single cell level. For example, recent work has demonstrated that cancer as a disease state is reached after the accumulation of damages that result in genetic errors. Other diseases like Huntingtons, Parkinsons, Alzheimers, cardiovascular disease are developed over time and their cellular mechanisms of disease transition are largely unknown. Modern techniques of disease characterization are perturbative, invasive and fully destructive to biological samples. Many methods need a probe or …

Computer-Aided Cancer Diagnosis And Grading Via Sparse Directional Image Representations, Hadi Rezaeilouyeh

Electronic Theses and Dissertations

Prostate cancer and breast cancer are the second cause of death among cancers in males and females, respectively. If not diagnosed, prostate and breast cancers can spread and metastasize to other organs and bones and make it impossible for treatment. Hence, early diagnosis of cancer is vital for patient survival. Histopathological evaluation of the tissue is used for cancer diagnosis. The tissue is taken during biopsies and stained using hematoxylin and eosin (H&E) stain. Then a pathologist looks for abnormal changes in the tissue to diagnose and grade the cancer. This process can be time-consuming and subjective. A reliable and …

Psychophysiological Analysis Of A Pedagogical Agent And Robotic Peer For Individuals With Autism Spectrum Disorders., Mohammad Nasser Saadatzi

Electronic Theses and Dissertations

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by ongoing problems in social interaction and communication, and engagement in repetitive behaviors. According to Centers for Disease Control and Prevention, an estimated 1 in 68 children in the United States has ASD. Mounting evidence shows that many of these individuals display an interest in social interaction with computers and robots and, in general, feel comfortable spending time in such environments. It is known that the subtlety and unpredictability of people’s social behavior are intimidating and confusing for many individuals with ASD. Computerized learning environments and robots, however, prepare a predictable, …

A Multi-Channel 3d-Printed Bioreactor For Evaluation Of Growth And Production In The Microalga Dunaliella Sp, Cristian A. Cox

Electronic Theses and Dissertations

We explored the capabilities of additive manufacturing using a photo-cured jetted material 3D printer to manufacture a milli-microfluidic device with direct application in microalgae Dunaliella sp growth and intracellular compounds biosynthesis tests. A continuous microbioreactor for microalgae culture was CAD designed and successfully built in 1 hour and 49 minutes using black photopolymer cured by UV and a support material. The microreactor was made up of 2 parts including the bioreactor itself and a microchannel network for culture media fluids and microalgae. Both parts were assembled to form a single unit. Additional optical and auxiliar components were added. An external …

Assessment Of Optimized Electrode Configuration In Electrical Impedance Myography Study Using Genetic Algorithm Via Finite Element Model, Somen Baidya

Electronic Theses and Dissertations

Electrical Impedance Myography (EIM) is a neurophysiologic technique in which high- frequency, low-intensity electrical current is applied via surface electrodes over a muscle or muscle group of interest and the resulting electrical parameters (resistance, reactance and phase) are analyzed to isolate diseased muscles from healthy ones. Beside muscle properties, some other anatomic and non-anatomic factors like muscle shape, subcutaneous fat (SF) thickness, inter-electrode distance, etc. also impact the major EIM parameters and thus affect the EIM analysis outcomes. The purpose of this study is to explore the effects of variation in some of these factors impose on EIM parameters and …

Microengineering The Neural Tube, Christopher Demers

Electronic Theses and Dissertations

Early embryonic development is a complex and highly regulated orchestra of instructive cues that collectively guide naïve stem cells towards progressively more specialized fates. In the neural tube, the precursor structure to the brain and spinal cord, these signals emanate from ‘organizing centers’ surrounding the neural tube. These organizing centers send out soluble cues or morphogens that diffuse tens to hundreds of microns to recipient cells residing in the neural tube. Re-creating this dynamic landscape of cues in vitro is impossible using standard cell culture tools and techniques. However, microfluidics is perfectly suited to fill this gap, allowing precise control …

Assessment Of Electrode Configurations Of Electrical Impedance Myography For The Evaluation Of Neuromuscular Diseases, Khondokar Mohammad Fazle Rabbi

Electronic Theses and Dissertations

Electrical impedance myography (EIM) is a painless, noninvasive approach to measure the neuromuscular disease status. EIM parameters- resistance (R), reactance (X) and phase (θ) depend significantly on subcutaneous fat thickness, muscle size and inter electrode distance. The objective of this research is to find an electrode configuration which can minimize the effects on EIM parameters due to subcutaneous fat thickness variation. In this study, a model of human upper arm was developed using finite element method (FEM), which has already been established as an appropriate approach for the analysis of non-symmetrical shape for assessing alternations of muscle in disease-induced changes …

Modeling Hrtf For Sound Localization In Normal Listeners And Bilateral Cochlear Implant Users, Douglas A. Miller

Electronic Theses and Dissertations

Mathematical models can be very useful for understanding complicated systems and for testing algorithms through simulation that would be difficult or expensive to implement. This dissertation presents a model that attempts to simulate the sound localization performance of persons using bilateral cochlear implants. The expectation is that this model could prove to be a useful tool in developing new signal processing algorithms for neural encoding strategies.

The head related transfer function (HRTF) is a critical component of this model, and in the ideal case, provides the base characteristics of head shadow, torso and pinna effects. This defines the temporal, intensity …

Biomechanical Comparison Of Lower Limb Unloading Between Common Modalities Of Ankle Foot Orthoses, Andrea Blake Wanamaker

Electronic Theses and Dissertations

Tibial stress fractures and other lower extremity injuries can be treated using an ankle foot orthosis (AFO). AFOs are popular because they allow the patient to ambulate somewhat naturally while reducing weight bearing on the injured limb. Despite their popularity, it is currently unclear how well AFOs reduce lower extremity weight bearing.

The first objective of this investigation was to examine the ability of three commonly used ankle foot orthoses to reduce weight bearing within the lower limb by comparing the ground reaction force measured from a force platform to the force measured from an insole pressure measurement device inside …

Computational Representation Of The Patellofemoral Joint, Abraham Wright

Electronic Theses and Dissertations

Many people suffer from knee pain due to abnormal function of the patellofemoral joint and are not able to enjoy normal activities of daily living. Surgical treatments are available and new methods are being developed by the medical industry. However, computational tools to efficiently evaluate the effects of the intervention on patellofemoral function are lacking.

Therefore, a validated and efficient computational model of the patellofemoral joint was developed. The subject specific finite element model was validated against the patellar kinematics recorded during cadaveric patellofemoral laxity experiments of the natural knee. The development involved a sequential process in which the soft-tissue …

A Model For Electrical Communication Between Cochlear Implants And The Brain, Douglas A. Miller

Electronic Theses and Dissertations

In the last thirty years, cochlear implants have become an invaluable instrument in the treatment of severe-to-profound hearing impairment. An important aspect of research in the continued development of cochlear implants is the in vivo assessment of signal processing algorithms intended to improve perception of speech and other auditory signals. In trying to determine how closely cochlear implant recipients process sound relative to the processing done by a normal auditory system, various assessment techniques have been applied. The most common technique has been measurement of auditory evoked potentials (AEPs), which involves the recording of neural responses to auditory stimulation. Depending …