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Theses/Dissertations

2002

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Articles 1 - 16 of 16

Full-Text Articles in Biomedical Engineering and Bioengineering

The Development Of A Biodegradable Scaffold For A Tissue Engineered Heart Valve, Thomas Adam Alheidt Dec 2002

The Development Of A Biodegradable Scaffold For A Tissue Engineered Heart Valve, Thomas Adam Alheidt

Theses

In the current state of medical technology, there exists the need for a quality medical device to replace a failing heart valve. Presently, mechanical valves as well as donor tissue valves, either from humans or animals are used to replace failing heart valves. These valves although they can operate in the heart satisfactorily are not equal to the body replacing its own valve. Tissue Engineering in simple terms is the field of helping the body replace its own failing organ. In scientific terms, Tissue Engineering is a relatively young field, a majority of the major advancements have come in the ...


Cortical Response To Facial Expressions Of Young Adult Males With Autism Spectrum Disorders And Controls Using Functional Magnetic Resonance Imaging (Fmri), Jagriti Arora Aug 2002

Cortical Response To Facial Expressions Of Young Adult Males With Autism Spectrum Disorders And Controls Using Functional Magnetic Resonance Imaging (Fmri), Jagriti Arora

Theses

Autism is a neurodevelopmental disorder that is defined by deficits in social and emotional impairments and this study aims to identify specific brain regions involved during facial processing. The simple task of focusing on the face during social interactions for the normal group is found difficult by the autistic group.

In this study, functional magnetic resonance imaging (fMRI) was used as subjects performed two experimental tasks (EXPLICIT and IMPLICIT) in which a series of photographs of nine males and nine females displaying three affective states (6 fear, 6 happy and 6 neutral) and six scrambled- face control stimuli were presented ...


Masseter Muscle Activity Resulting From Stimulation Of Hypothalamic Behavioral Sites : Wavelet Analysis, Anne Marie Petrock Aug 2002

Masseter Muscle Activity Resulting From Stimulation Of Hypothalamic Behavioral Sites : Wavelet Analysis, Anne Marie Petrock

Theses

Patterns of electromyographic (EMG) activity can give an insight into muscle activity associated with a given behavioral state. The masseter muscle is positioned closely to the temporomandibular joint and controls the position and movement of the jaw. The hypothalamus is the region of the brain associated with emotional behavior. In an effort to further understand the muscle activity underlying emotional display, the hypothalamus in two cats was stimulated to evoke a stereotyped emotional response, known as the "rage response." Unsheathing of the claws, retraction of the ears, significant pupillary dilation and vocalization (hissing) characterize this behavior. EMG data obtained at ...


Quantitative Assessment Of Reflex Blood Pressure Regulation Using A Dynamic Model Of The Cardiovascular System, Tanha Patel Aug 2002

Quantitative Assessment Of Reflex Blood Pressure Regulation Using A Dynamic Model Of The Cardiovascular System, Tanha Patel

Theses

A quantitative understanding of the changes in coronary, pulmonary and systemic hemodynamic variables and their effects on the regulation mechanism is important to the better postoperative management of patients with impaired cardiac function. The arterial baroreflex plays a key role in blood pressure homeostasis, and its impairment may result in exaggerated blood pressure fluctuations and an increased risk of cardiovascular morbid events.

The objective of this work was to construct a mathematical model of the cardiovascular system, which will allow us to simulate the effects of the baroreceptor reflex regulation on sudden changes in blood pressure, caused by sudden changes ...


Dimensional Study Of Desaminotyrosyl Polyarylates, Kalsank Vaishali Pai Aug 2002

Dimensional Study Of Desaminotyrosyl Polyarylates, Kalsank Vaishali Pai

Theses

Synthetic polymers have found widespread usage and acceptance in various areas of the medical device industry. The recognition that no polymeric biornaterials are truly biocompatible has led to the search for bioerodible materials with desirable biological and physical properties for use as tissue engineering scaffolds and to enable in-vivo devices. Several methodologies have been tried and tested to invent the "ideal" biopolymer. The ideal polymeric biomaterial would be one that offers a favorable response at both the cellular and the systemic level with minimum alteration to its mechanical properties and chemistry. The systematic investigation of process-structure-property space to determine the ...


Molecular Characterization Of The T(4;9)12gso Mutation And Analysis Of The Associated Fitness, Skeletal, And Lymphoproliferative Phenotypes, Laura Ray Chittenden Aug 2002

Molecular Characterization Of The T(4;9)12gso Mutation And Analysis Of The Associated Fitness, Skeletal, And Lymphoproliferative Phenotypes, Laura Ray Chittenden

Doctoral Dissertations

The t(4;9)(B3;E3.2)12Gso reciprocal translocation is an autosomal recessive mouse mutation involving chromosome 4, band B3 (Mmu4B3) and chromosome 9, band E3.2 (Mmu9E3.2). The most striking phenotype of the 12Gso homozygote involves axial skeleton deformities, resulting in significant shortening of body length, scoliosis, displaced hips and kinky tails. Homozygous animals are significantly smaller than normal littermates and frequently exhibit early lethality, as many of the mutants perish by 1 day postnatal, and many others do not survive the three weeks to weaning age. Homozygous 12Gso mice also develop an unusual bone marrow defect ...


Modular Machine Learning Methods For Computer-Aided Diagnosis Of Breast Cancer, Mia Kathleen Markey '94 Jun 2002

Modular Machine Learning Methods For Computer-Aided Diagnosis Of Breast Cancer, Mia Kathleen Markey '94

Doctoral Dissertations

The purpose of this study was to improve breast cancer diagnosis by reducing the number of benign biopsies performed. To this end, we investigated modular and ensemble systems of machine learning methods for computer-aided diagnosis (CAD) of breast cancer. A modular system partitions the input space into smaller domains, each of which is handled by a local model. An ensemble system uses multiple models for the same cases and combines the models' predictions.

Five supervised machine learning techniques (LDA, SVM, BP-ANN, CBR, CART) were trained to predict the biopsy outcome from mammographic findings (BIRADS™) and patient age based on a ...


A Computational Model Of Spasticity Based On A Decoupling Of The Alpha And Gamma Efferents, Bruno A. Mantilla May 2002

A Computational Model Of Spasticity Based On A Decoupling Of The Alpha And Gamma Efferents, Bruno A. Mantilla

Theses

It is generally accepted that spasticity results from changes in the excitability of the stretch reflex. This change lowers the threshold of the motoneurons of the spinal cord where the integration of a signal from velocity/position sensors is processed and then fed back to the contracting muscle (alphaextrafusal and gamma-intrafusal fibers). The stretch reflex depends on the initial length of the muscle, the stretch velocity and voluntary activity. The exact sequence of the triggering events remains unknown, is poorly understood and as a result is controversial. The clinical classification scales are mainly subjective and by definition, inaccurate.

This computational ...


Development Of A Method To Examine Shear Stress On Cardiomyocytes, Dhawal Desai May 2002

Development Of A Method To Examine Shear Stress On Cardiomyocytes, Dhawal Desai

Theses

Cardiac hypertrophy is the remodeling or enlargement of the heart exhibited by individuals suffering from heart disease. Cardiac hypertrophy involves two mechanisms, mechanical stresses and humoral changes in the cardiac tissue. One such humoral change involves the Renin Angiotensin System (RAS). The primary fimction of RAS is maintenance of hemodynamics of the body mediated through an effector protein, Angiotensin 11. However, RAS has been shown to play a significant role in the pathophysiology of the heart; contributing to hypertension, cardiac hypertrophy and myocardial infarction. RAS acts through binding of Angiotensin 11 at its receptors. The two forms of Angiotensin 11 ...


Impact Of Intraocular Pressure Maintenance On Sight Preservation, Marla D. Ratliff B.S. May 2002

Impact Of Intraocular Pressure Maintenance On Sight Preservation, Marla D. Ratliff B.S.

Theses and Dissertations

Ratliff, Marla D., Impact of Intraocular Pressure Maintenance on Sight Preservation. Master of Public Health (Health Services Research), May 2002, 35 pp., 3 tables, 1 figure, 40 titles. Purpose: The objective of the study was to review diurnal IOP control and its impact on sight preservation. Methods: This is a retrospective study used in patients with elevated IOP. Patient IOPs were measured every 4 hours over a 24-hour period. Qualified patients provided open label TRAVATAN to dose once a day for 2 weeks. Following 2 weeks of dosing, IOP measurements were taken every 4 hours for 36 hours. Additional IOP ...


Evapotranspiration Using A Satellite-Based Surface Energy Balance With Standardized Ground Control, Ricardo Trezza May 2002

Evapotranspiration Using A Satellite-Based Surface Energy Balance With Standardized Ground Control, Ricardo Trezza

All Graduate Theses and Dissertations

This study evaluated the potential of using the Surface Energy Balance Algorithm for Land (SEBAL) as a means for estimating evapotranspiration (ET) for local and regional scales in Southern Idaho. The original SEBAL model was refined during this study to provide better estimation of ET in agricultural areas and to make more reliable estimates of ET from other surfaces as well, including mountainous terrain. The modified version of SEBAL used in this study, termed as SEBALID (lD stands for Idaho) includes standardization of the two SEBAL "anchor" pixels, the use of a water balance model to track top soil moisture ...


Behavior Of Nano-Engineered Platelets In A Coronary Artery Stenosis Model, Hua Ai Apr 2002

Behavior Of Nano-Engineered Platelets In A Coronary Artery Stenosis Model, Hua Ai

Doctoral Dissertations

Cardiovascular disease is the leading cause of death in North America. Cardiac infarction caused by thrombus plaque rupture can often lead to sudden death. Arterial stenosis caused by atherosclerosis is an important precursor leading to thrombus formation. Shear stress, abnormal lipid metabolism, and subendothelial layer exposure are the major contributors to arterial thrombus formation. Platelet activation by the above factors, followed by adhesion is the basic sequence in thrombus formation.

Platelets were encapsulated with nanofilm in order to reduce platelet activation and adhesion under high shear stress. Polyions, nanoparticles and immunoglobulins were assembled in nano-organized shells on fixed bovine platelets ...


Defining Benthic Organism Exposure: Bioavailability And Effects Of Non-Polar Organics, Marc Samuel Greenberg Jan 2002

Defining Benthic Organism Exposure: Bioavailability And Effects Of Non-Polar Organics, Marc Samuel Greenberg

Browse all Theses and Dissertations

Laboratory and field tests were conducted to evaluate the hypothesis that factors such as the total organic carbon (TOC) contents and groundwater-surface water interactions (GSI) in the sediments can affect chemical desorption, bioavailability and benthic organism exposure. Laboratory studies were conducted with the polycyclic aromatic hydrocarbon fluoranthene (FLU) and the herbicide trifluralin (TF). Toxicokinetic parameters were determined for Lumbriculus variegatus and Hyalella azteca in water-only exposures to 0, 5, 20 and 50 µg/L of the compounds and bioaccumulation was measured during exposures to 0, 100 and 200 mg/kg of FLU and TF spiked onto sediments from Lakes Erie ...


Development Of Novel Polymeric Materials For Gene Therapy And Ph-Sensitive Drug Delivery: Modeling, Synthesis, Characterization, And Analysis , Brian Curtis Anderson Jan 2002

Development Of Novel Polymeric Materials For Gene Therapy And Ph-Sensitive Drug Delivery: Modeling, Synthesis, Characterization, And Analysis , Brian Curtis Anderson

Retrospective Theses and Dissertations

The aim of this work was to obtain a fundamental understanding of drug release mechanisms from polymers that undergo thermoreversible gelation and to synthesize new polymers based on these that exhibit both pH and temperature sensitivity. Novel block and random copolymers with cationic character have been developed for drug delivery and gene therapy applications. The development of these materials began with a study of the mechanism of drug release from poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) block copolymers. This study revealed the release rates of drugs from water-soluble hydrogels composed of the PEO-PPO-PEO block copolymer PluronicRTM F127 ...


Calcium Phosphate Compatible Bone Cement: Characterization, Bonding Properties And Tissue Response , Maria Lynn Roemhildt Jan 2002

Calcium Phosphate Compatible Bone Cement: Characterization, Bonding Properties And Tissue Response , Maria Lynn Roemhildt

Retrospective Theses and Dissertations

A novel, inorganic, bone cement, containing calcium phosphate, developed for implant fixation was evaluated. Setting properties were determined over a range of temperatures. The flow of the cement was greatly increased by application of vibration. Changes in the cement during hydration and aging were evaluated. Compressive strength of the cement over time was studied under simulated physiological conditions from 1 hour to 1 year after setting. After 1 day, this cement had equivalent compressive strength to commercially used PMMA cement. The strength was found to increase over 1 month and high strength was maintained up to 1 year.;The shear ...


Physical-Statistical Modeling And Optimization Of Cardiovascular Systems, Dongping Du Jan 2002

Physical-Statistical Modeling And Optimization Of Cardiovascular Systems, Dongping Du

Graduate Theses and Dissertations

Heart disease remains the No.1 leading cause of death in U.S. and in the world. To improve cardiac care services, there is an urgent need of developing early diagnosis of heart diseases and optimal intervention strategies. As such, it calls upon a better understanding of the pathology of heart diseases.

Computer simulation and modeling have been widely applied to overcome many practical and ethical limitations in in-vivo, ex-vivo, and whole-animal experiments. Computer experiments provide physiologists and cardiologists an indispensable tool to characterize, model and analyze cardiac function both in healthy and in diseased heart. Most importantly, simulation modeling ...