Biomedical Engineering and Bioengineering Commons^™

Evaluation Of Spatial Resolution And Localization Accuracy Of Absorbing Heterogenity Embedded In Homogenous And Layered Turbid Media Using Functional Near Infrared Spectroscopy, Niranjana Nandakumar

Bioengineering Theses - Archive

Functional Near-Infrared Spectroscopy (fNIRS) is a non-invasive widely used technique for imaging the brain activation patterns in the cerebral cortex of neonates and adults. For the fNIRS imaging of these brain activation patterns, it is common to assume the head geometry as a homogenous medium due to the resulting computational simplicity of the image reconstruction problem. In reality the head is not a simple homogenous medium and prior research has been conducted to show that light propagates differently in a spatially heterogeneous model of the head compared to a homogenous one, which alters the sensitivity of NIR light detection on …

A Multimodality Dlp® Imaging System For Clinical Surgery, Michael Lee Mangum

Bioengineering Theses - Archive

With 1.38 million new cases and 450,000 deaths worldwide due to breast cancer, there is a clear need for safe and complete surgical intervention for the treatment of breast cancer. Imaging solutions have been created and developed to help plastic surgeons during breast reconstructive surgery. However, these solutions were implemented separately depending on their particular modality, which can result in higher costs for hospital and patient use. The digital micromirror device (DMD) developed by Texas Instruments has been shown to exhibit spectral control of light at a digital level, and could theoretically allow for the incorporation of multiple imaging modalities …

Three-Dimensional Multimedium Computational Model For Drug Delivery Using Finite Element Analysis, Eduardo Martinez

Bioengineering Theses - Archive

Approximately 2.8% of trauma patients present peripheral nerve injury, which can result in loss of motor function. Current strategies for peripheral nerve repair had focused on the development of synthetic nerve conduits that provide physical guidance. One advantage of the synthetic nerve conduits is that the conduit can be utilize as a delivery system and gain the ability to deliver neurotrophic factors, which have an effect on controlling the survival, migration, proliferation, and differentiation of different neural cell types. Currently there is no method to quantify the concentration of growth factors in the nerve conduit during the implantation time. In …

Estimation Of The Centre Of Mass From Motion Capture And Force Plate Recordings: A Study On The Elderly, Sebastien Cotton, Michele Vanoncini, Philippe Fraisse, Nacim Ramdani, Emel Demircan, Andrew P. Murray, Thierry Keller

Mechanical and Aerospace Engineering Faculty Publications

The estimation of the centre of mass position in humans is usually based on biomechanical models developed from anthropometric tables. This method can potentially introduce errors in studies involving elderly people, since the ageing process is typically associated with a modification of the distribution of the body mass. In this paper, an alternative technique is proposed, and evaluated with an experimental study on 9 elderly volunteers. The technique is based on a virtual chain, identified from experimental data and locating the subject's centre of mass. Its configuration defines the location of the centre of mass, and is a function of …

The Feasibility Of Using Bifidobacteria Bifidum (Atcc 700541) For The Production Of Prebiotic Oligosaccharides, Candice Marie Luehrs

Masters Theses

"Galactooligosaccharides (GOS) are prebiotics that are being used to influence intestinal microbiota towards health promoting, beneficial bacteria like bifidobacteria. Natural sources of GOS are not found in suitable levels to achieve the desired health effects so economically viable commercial production methods are important. Enzymatic conversion of lactose to GOS through transgalactosylation is a preferred method since the starting material is inexpensive and readily available. Enzymes used in batch production are purified from fungal or bacterial sources or remain in whole cells cultured for GOS production. Purified or unbound enzymes are single use whereas enzymes retained within whole cells can potentially …

Arteriogenesis And Ischemia Impair Functional Vasodilation In Resistance Arteries, Trevor Cardinal, Joseph S. Zhu, Kyle R. Struthers, Thomas J. Kesler, Matthew D. Yocum

Biomedical Engineering

No abstract provided.

Arterial Tissue Perforation Using Ultrasonically Vibrating Wire Waveguides, Mark Wylie

Doctoral

Chronic Total Occlusions (CTOs) are fibrous and calcified atherosclerotic lesions which completely occlude the artery. They are difficult to treat with standard dilation procedures as they cannot be traversed easily. Their treatment is also associated with a high risk of arterial perforation. Low frequency ultrasonic vibrations delivered via wire waveguides represent a minimally invasive treatment for CTOs and other tissue ablation applications. These devices typically operate at 20–50 kHz delivering wire waveguide distal tip amplitudes of vibration of 0-60 μm. The diseased tissue is ablated or disrupted by repetitive direct mechanical contact and cavitation. This research assesses the susceptibility of …

Modeling And Quantitative Analysis Of White Matter Fiber Tracts In Diffusion Tensor Imaging, Xuwei Liang

University of Kentucky Doctoral Dissertations

Diffusion tensor imaging (DTI) is a structural magnetic resonance imaging (MRI) technique to record incoherent motion of water molecules and has been used to detect micro structural white matter alterations in clinical studies to explore certain brain disorders. A variety of DTI based techniques for detecting brain disorders and facilitating clinical group analysis have been developed in the past few years. However, there are two crucial issues that have great impacts on the performance of those algorithms. One is that brain neural pathways appear in complicated 3D structures which are inappropriate and inaccurate to be approximated by simple 2D structures, …

The Effect Of Practice On Eye Movements In The 1/D Paradigm, Will Seidelman

University of Kentucky Master's Theses

Previous studies have demonstrated that observers may ignore highly salient feature singletons during a conjunction search task through focusing the attentional window (Belopolsky, Zwaan, Theeuwes, & Kramer, 2007), or by the suppression of bottom-up information (Treisman & Sato, 1990). In the current study, observers’ eye movements were monitored while performing a search task in which a feature singleton was present and corresponded with the target at a chance level. With practice, observers were less likely to make an initial saccade toward the singleton item, but initial saccades directed at the target were likely throughout. Results demonstrate that, in an effort …

Effects Of Acute Rho Kinase Inhibition On Chronic Hypoxia-Induced Changes In Proximal And Distal Pulmonary Arterial Structure And Function, Rebecca R. Vanderpool, Ah Ram Kim, Robert C. Molthen, Naomi Chesler

Biomedical Engineering Faculty Research and Publications

Hypoxic pulmonary hypertension (HPH) is initially a disease of the small pulmonary arteries. Its severity is usually quantified by pulmonary vascular resistance (PVR). Acute Rho kinase inhibition has been found to reduce PVR toward control values in animal models, suggesting that persistent pulmonary vasoconstriction is the dominant mechanism for increased PVR. However, HPH may also cause proximal arterial changes, which are relevant to right ventricular (RV) afterload. RV afterload can be quantified by pulmonary vascular impedance, which is obtained via spectral analysis of pulsatile pressure-flow relationships. To determine the effects of HPH independent of persistent pulmonary vasoconstriction in proximal and …

Visual And Proprioceptive Contributions To Compensatory And Pursuit Tracking Movements In Humans, Megan L. Heenan, Robert A. Scheidt, Scott A. Beardsley

Biomedical Engineering Faculty Research and Publications

An ongoing debate in the field of motor control considers how the brain uses sensory information to guide the formation of motor commands to regulate movement accuracy. Recent research has shown that the brain may use visual and proprioceptive information differently for stabilization of limb posture (compensatory movements) and for controlling goal-directed limb trajectory (pursuit movements). Using a series of five experiments and linear systems identification techniques, we modeled and estimated the sensorimotor control parameters that characterize the human motor response to kinematic performance errors during continuous compensatory and pursuit tracking tasks. Our findings further support the idea that pursuit …

Cardiac Magnetic Resonance Imaging Can Detect Early Vascular Changes In Children With Type 1 Diabetes (T1dm), Margaret M. Samyn, Pippa Simpson, Michael E. Widlansky, Mary M. Krolikowski, Jennifer Co-Vu, Ronak Jashwant Dholakia, John F. Ladisa, Ramin Alemzadeh

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Influence Of Design Parameters On Cup-Stem Orientations For Impingement Free Range Of Motion In Hip Implants, Dishita Prakashbhai Patel

Browse all Theses and Dissertations

The objective of this investigation is to determine the optimum positions of the prosthesis in total hip arthroplasty that produce least amount of impingement. Theoretical ranges of six basic hip motions were determined under walking, stumbling, internal rotation at 90 flexion and external rotation at 0 extension with 15 abduction, using mathematical models and validated for impingement using finite element analysis. A generalized approach, where impingement does not occur, was developed in this study to understand influence of design parameters such as head-neck ratio, neck-shaft angle, oscillation angle, and stem offset on cup-stem orientations such as cup inclination, cup anteversion, …

A Validation Of A Prototype Dry Electrode System For Electroencephalography, Jason Monnin

Browse all Theses and Dissertations

Current physiologically-driven operator cognitive state assessment technology relies primarily on electroencephalographic (EEG) signals. Traditionally, gel-based electrodes have been used; however, the application of gel-based electrodes on the scalp requires expertise and a considerable amount of preparation time. Additionally, discomfort can occur from the abrasion of the scalp during preparation, and the electrolyte will also begin to dry out over extended periods of time. These drawbacks have hindered the transition of operator state assessment technology into an operational environment. QUASAR, Inc., (San Diego, CA) has developed a prototype dry electrode system for electroencephalography that requires minimal preparation. A comparison of the …

Neurorehabilitation Of The Hand Using The Cybergrasp[Tm] And Mirror Image, Amy Frances Boos

Theses

In recent years, researchers have explored the use of a mirror image as a means of rehabilitation for individuals suffering from hemiparesis. Through neuroimaging and functional testing, neurological improvement has been demonstrated in those that engage in mirror therapy. Bilateral training, or simultaneous movement of both sides of the body, has also been studied as a treatment method to improve function after cerebral vascular accident. The development of robotic systems to assist movement of the human body has played a major role in the fabrication of bilateral training devices.

In this experiment, the CyberGrasp™ robotic exoskeleton was used to assist …

Longissimus Muscle Fatigue And Injury Response Due To Electrical Stimulation With Varied Work/Rest Ratios, Peter Wawrow

Wayne State University Dissertations

LONGISSIMUS MUSCLE FATIGUE AND INJURY RESPONSE DUE TO ELECTRICAL STIMULATION WITH VARIED WORK/REST RATIOS

BY

PETER WAWROW

May 2011

Advisor: John Cavanaugh, MD

Major: Biomedical Engineering

Degree: Doctor of Philosophy

The estimated yearly cost of lost-time work injuries and illnesses is $140 billion. The average cost of musculoskeletal disorders (MSDs) exceeds all other claims. These injuries persist in spite of ergonomic interventions addressing known risk factors. Work/rest ratios have not received a significant amount of attention, particularly in low back disorders, and it is hypothesized that the lack of adequate rest within a work cycle may contribute to muscle fatigue …

Monitoring, Diagnosis, And Control For Advanced Anesthesia Management, Zhibin Tan

Wayne State University Dissertations

Modern anesthesia management is a comprehensive and the most critical issue in medical care. During the past dacades, a large amount of research works have been focused on the problems of monitoring anesthesia depth, modeling the dynamics of anesthesia patient for the purpose of control, prediction, and diagnosis.

Monitoring the anesthesia depth is not only for keeping the patient in adquate anesthesia level but also for preventing the patient from overdosing. Several EEG based indexes have been developed such as the BIS, and Entropy etc. for measuring depth. However, reports mentioned that those indexes in some cases fail in detecting …

Processing Random Signals In Neuroscience, Electrical Engineering And Operations Research, Kalyan Raman

Wayne State University Dissertations

The topic of this dissertation is the study of noise in electrical engineering, neuroscience, biomedical engineering, and operations research through mathematical models that describe, explain, predict and control dynamic phenomena. Noise is modeled through Brownian Motion and the research problems are mathematically addressed by different versions of a generalized Langevin equation. Our mathematical models utilize stochastic differential equations (SDEs) and stochastic optimal control, both of which were born in the soil of electrical engineering. Central to this dissertation is a brain-physics based model of cerebrospinal fluid (CSF) dynamics, whose structure is fundamentally determined by an electrical circuit analogy. Our general …

Computational Analyses Of The Uptake And Distribution Of Carbon Monoxide (Co) In Human Subjects, Kinnera Chada

University of Kentucky Doctoral Dissertations

Carbon monoxide (CO) is an odorless, colorless, tasteless gas that binds to hemoglobin with high affinity. This property underlies the use of low doses of CO to determine hemoglobin mass (M_Hb) in the fields of clinical and sports medicine. However, hemoglobin bound to CO is unable to transport oxygen and exposure to high CO concentrations is a significant environmental and occupational health concern. These contrasting aspects of CO—clinically useful in low doses but potentially lethal in higher doses—mandates a need for a quantitative understanding of the temporal profiles of the uptake and distribution of CO …

Quantitative Computed-Tomography Based Bone-Strength Indicators For The Identification Of Low Bone-Strength Individuals In A Clinical Environment, Bino Abel Varghese

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The aim of the current study was to develop quantitative computed-tomography (QCT)-based bone-strength indicators that highly correlate with finite-element (FE)-based strength. We perform a combined numerical-experimental study, comparing FE-predicted surface strains with strain gauge measurements, to validate the FE models of 36 long bones (humerus, radius, femur and tibia) under three-point bending and torsion. The FE models were constructed from trans-axial volumetric CT scans, and the segmented bone images were corrected for partial-volume effects. The material properties (Young's modulus for cortex, density-modulus relationship for trabecular bone and Poisson's ratio) were calibrated by minimizing the error between experiments and simulations among …