Biomedical Engineering and Bioengineering Commons^™

Atrial Fibrillation Signal Analysis, Raja Sarath Chandra Prasad Vaizurs

USF Tampa Graduate Theses and Dissertations

Atrial fibrillation (AF) is the most common type of cardiac arrhythmia encountered in clinical practice and is associated with an increased mortality and morbidity. Identification of the sources of AF has been a goal of researchers for over 20 years. Current treatment procedures such as Cardio version, Radio Frequency Ablation, and multiple drugs have reduced the incidence of AF. Nevertheless, the success rate of these treatments is only 35-40% of the AF patients as they have limited effect in maintaining the patient in normal sinus rhythm. The problem stems from the fact that there are no methods developed to analyze …

Biological Effective Dose (Bed) Distribution Matching For Obtaining Brachytherapy Prescription Doses & Dosimetric Optimization For Hybrid Seed Brachytherapy, Jakub Pritz

USF Tampa Graduate Theses and Dissertations

Radioactive seed implant brachytherapy is a common radiotherapy treatment method for prostate cancer. In current clinical practice, a seed consists of a single isotope, such as ¹²⁵I or ¹⁰³Pd. A seed containing a mixture of two isotopes has been proposed for prostate cancer treatment. This study investigates a method for defining a prescription dose for new seed compositions based on matching the biological equivalent dose (BED) of a reference plan.

Ten prostate cancer cases previously treated using single isotope seeds (5 using ¹²⁵I seeds and 5 using ¹⁰³Pd seeds) were selected for this study. Verification of …

Two-Dimensional Computer Model Of Human Atrial Ablation, Samineh R. Esfahani

USF Tampa Graduate Theses and Dissertations

A finite-element model of a two-dimensional slice of human atrial tissue for the study of the electrograms and propagation of action potentials is presented. Action potential propagation is described by a reaction-diffusion model coupled with the complex Courtemanche et al. atrial cell model. The effects of recording electrode size and location on electrograms are presented. Action potential propagation as a result of atrial fibrillation ablation therapy is also modeled by defining a lesion area with decreased electrical conductivity. The effect of electrical conductivity and geometry of the lesion was also studied. It is shown that the success rate of atrial …

The Role Of Conflict Management On Virtual Team Performance And Satisfaction, Pilar Pazos, Anil Ustun, Rolando Delaguila

Engineering Management & Systems Engineering Faculty Publications

The role that input factors from project planning processes play on conflict emergence and conflict resolution in virtual teams is not well understood. Of particular interest for this paper is the role that factors during planning stages play in preventing interpersonal conflict, supporting conflict resolution and ultimately enhancing team outcomes in virtual team settings. This study examines the relationships among commitment to team goals, conflict management and team outcomes in virtual teams. First we provide an in depth review of relevant empirical findings. Next, we describe a study examining the relationships between three sets of variables: 1) goal commitment, 2) …

Composition-Structure-Property Relationships For Experimental Composite Nerve Guidance Conduits, Xiaofang Zhang

Theses

Many Nerve Guidance Conduits (NGCs) have been approved by the Food and Drug Administration (FDA) as an alternative to nerve autografting for guiding peripheral nerve regeneration. However these materials offer little therapeutic potential for favourable axon growth environment, and difficulty in balancing the mechanical properties and the degradation rate of the implanted material is also a contemporary challenge. This project involved the design of experimental composite NGCs comprising glass particles and Pluronic FI27 in the copolymer (poly(lactic-co-glycolic acid)) and examined the composition-structure-property relationships for such materials. Three glasses (0.5Si-(x) Na-0.2Ca-0.13Zn-(0.17-x) Ce) (0.0.04 > x > 0.14) were produced. Glasses were characterised using …

On Improving Electrooculogram-Based Computer Mouse Systems: The Accelerometer Trigger, Johnalan Keegan, Edward Burke, James Condron, Eugene Coyle

Conference Papers

Eye tracking is a well-established method of computer control for profoundly paralysed people (Anson et al., 2002). Cameras are commonly used to track eye movements (Morimoto et al., 2005) but one alternative is the bioelectrical signal known as the electrooculogram (EOG). There are some EOG mouse control systems that facilitate the use of GUI applications, but certain actions, which are straightforward using a conventional mouse, remain impossible. Unless the eyes are tracking a target, they move in saccades (jumps), making it impossible to voluntarily trace out smooth trajectories with one's gaze, as would be required to draw a smooth curve. …

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 …

Blood Vessel Diameter Estimation System Using Active Contours, Jane Courtney, Ana Tizon

Conference Papers

The study and analysis of blood vessel geometry has become the basis of medical applications related to early diagnosis and effective monitoring of therapies in vascular diseases. This paper presents a new method to trace the outline of blood vessels from imperfect images and extract useful information about their dimensions in an automated manner. The system consists of a segmentation procedure that uses two Active Contours to detect blood vessel boundaries and a novel approach to measure blood vessel diameters directly as the distance between two points. We have succeeded in designing and implementing an automated, robust, measurement method that …

Analysis Of The Performance Of Peanut Fame In A Single Cylinder Idi Engine And Investigations Of Neat Methyl Ester Influence On Fuel Quality, Jeffery Lewis

College of Graduate Studies: Theses & Dissertations

Author's abstract: To meet evolving standards set forth by the U.S. EPA and U.S. Energy Policy it is necessary to consider a variety of feedstock for biofuels synthesis and to understand the role individual fatty acids contribute to the overall performance. It is the belief of the authors that excess peanut production would provide an excellent source for high quality biodiesel feedstock, and the complete property and combustion analysis of the fatty acid components will provide insight for future biofuel developments. The preliminary investigations of the project focused on the combustion performance and thermal efficiency of peanut FAME and its …

Biophysical Properties Of The Aorta In Patients With Marfan Syndrome And Related Connective Tissue Disorders: Evaluation With Mri And Computational Fluid Dynamics Modeling, Joseph A. Camarda, Michael G. Earing, Ronak Jashwant Dholakia, Hongfeng Wang, Sung Kwon, John F. Ladisa Jr., Margaret M. Samyn

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Sensory Motor Remapping Of Space In Human-Machine Interfaces, Ferdinando A. Mussa-Ivaldi, Maura Casadio, Zachary C. Danziger, Kristine M. Mosier, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Studies of adaptation to patterns of deterministic forces have revealed the ability of the motor control system to form and use predictive representations of the environment. These studies have also pointed out that adaptation to novel dynamics is aimed at preserving the trajectories of a controlled endpoint, either the hand of a subject or a transported object. We review some of these experiments and present more recent studies aimed at understanding how the motor system forms representations of the physical space in which actions take place. An extensive line of investigations in visual information processing has dealt with the issue …

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.

Energy Deposition In The Breast During Ct Scanning: Quantification And Implications For Dose Reduction, Franco Rupcich, Iacovos Kyprianou, Andreu Badal, Taly Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

Studies suggest that dose to the breast leads to a higher lifetime attributable cancer incidence risk from a chest CT scan for women compared to men. Numerous methods have been proposed for reducing dose to the breast during CT scanning, including bismuth shielding, tube current modulation, partial-angular scanning, and reduced kVp. These methods differ in how they alter the spectrum and fluence across projection angle. This study used Monte Carlo CT simulations of a voxelized female phantom to investigate the energy (dose) deposition in the breast as a function of both photon energy and projection angle. The resulting dose deposition …

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 …

Multimodality Imaging Of Abnormal Vascular Perfusion And Morphology In Preclinical 9l Gliosarcoma Model, Moses M. Darpolor, Robert C. Molthen, Kathleen M. Schmainda

Biomedical Engineering Faculty Research and Publications

This study demonstrates that a dynamic susceptibility contrast-magnetic resonance imaging (DSC-MRI) perfusion parameter may indicate vascular abnormality in a brain tumor model and reflects an effect of dexamethasone treatment. In addition, X-ray computed tomography (CT) measurements of vascular tortuosity and tissue markers of vascular morphology were performed to investigate the underpinnings of tumor response to dexamethasone.

Effects Of Wrist Tendon Vibration On Targeted Upper-Arm Movements In Poststroke Hemiparesis, Megan O. Conrad, Robert A. Scheidt, Brian D. Schmit

Biomedical Engineering Faculty Research and Publications

Background. Impaired motor control of the upper extremity after stroke may be related to lost sensory, motor, and integrative functions of the brain. Artificial activation of sensory afferents might improve control of movement by adding excitatory drive to sensorimotor control structures. The authors evaluated the effect of wrist tendon vibration (TV) on paretic upper-arm stability during point-to-point planar movements. Methods. TV (70 Hz) was applied to the forearm wrist musculature of 10 hemiparetic stroke patients as they made center-out planar arm movements. End-point stability, muscle activity, and grip pressure were compared as patients stabilized at the target position …

Reorganization Of Finger Coordination Patterns During Adaptation To Rotation And Scaling Of A Newly Learned Sensorimotor Transformation, Xiaolin Liu, Kristine M. Mosier, Ferdinando A. Mussa-Ivaldi, Maura Casadio, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

We examined how people organize redundant kinematic control variables (finger joint configurations) while learning to make goal-directed movements of a virtual object (a cursor) within a low-dimensional task space (a computer screen). Subjects participated in three experiments performed on separate days. Learning progressed rapidly on day 1, resulting in reduced target capture error and increased cursor trajectory linearity. On days 2 and 3, one group of subjects adapted to a rotation of the nominal map, imposed either stepwise or randomly over trials. Another group experienced a scaling distortion. We report two findings. First, adaptation rates and memory-dependent motor command updating …

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 …

A Quantitative And Standardized Robotic Method For The Evaluation Of Arm Proprioception After Stroke, Lucia Simo, Claude Ghez, Lior Botzer, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Stroke often results in both motor and sensory deficits, which may interact in the manifested functional impairment. Proprioception is known to play important roles in the planning and control of limb posture and movement; however, the impact of proprioceptive deficits on motor function has been difficult to elucidate due in part to the qualitative nature of available clinical tests. We present a quantitative and standardized method for evaluating proprioception in tasks directly relevant to those used to assess motor function. Using a robotic manipulandum that exerted controlled displacements of the hand, stroke participants were evaluated, and compared with a control …

A Database For Estimating Scanner-Specific Ct Dose, Taly Gilat-Schmidt

Biomedical Engineering Faculty Research and Publications

Purpose: To develop a database for estimating scanner-specific organ dose in a voxelized patient model for any spectral shape and angular tube current modulation setting. The database enables the estimation of organ dose for both existing and novel acquisition techniques without requiring Monte Carlo simulations.

Methods: The transport of monoenergetic photons through three phantoms was simulated with the PENELOPE Monte Carlo radiation transport routines at 5 – 150 keV in 1 keV increments at 1000 projections in 0.36 degree increments. The source-to-detector distance for each simulation was 100 cm, with a source-to-isocenter distance of 50 cm. The lateral and axial …