Engineering Commons^™

Automated Myocardial Infarction Diagnosis From Ecg, Chen Zhou

Doctoral Dissertations

In the present dissertation, an automated neural network-based ECG diagnosing system was designed to detect the presence of myocardial infarction based on the hypothesis that an artificial neural network-based ECG interpretation system may improve the clinical myocardial infarction. 137 patients were included. Among them 122 had myocardial infarction, but the remaining 15 were normal. The sensitivity and the specificity of present system were 92.2% and 50.7% respectively. The sensitivity was consistent with relevant research. The relatively low specificity results from the rippling of the low pass filtering. We can conclude that neural network-based system is a promising aid for the …

Encoding And Storage Components Of Verbal Working Memory As Revealed By A Factorial Design, An Fmri Study, Jason Steffener

Theses

In this fMRI study, the contributions of frontal and posterior brain regions to verbal working memory were investigated. A two-factor design with low and high memory load (2 and 5 letters) and short and long delay (4 and 12 secs.) as factors were used. Based on reports in the literature, we expect activity in the following frontal and parietal brain regions of interest (ROIs): Brodmann areas (BA) 6, 9, 46, 44, 45, 7 and 40. The analysis of collected flvM data involved image processing and statistical analysis methods including realignment, spatial normalization, spatial smoothing, temporal filtering, intensity normalization, statistical tests, …

Initial Hertzian Characteristics Of The Human Tooth As A Damage Tolerant Bio-Ceramic/Bio-Composite Bi-Layer, Ivory Camille Kilpatrick

Theses

The objective of this thesis was to investigate the Hertzian Contact response of human teeth and how the response behavior is related to that of model ceramic bi-layers (high modulus brittle ceramics on compliant substrates). Hertzian Contact is a blunt indentation method, which uses a hard spherical indenter to apply a normal compressive load. Clinical variables of masticatory (occlusal) force and cuspal curvature identify closely with the independent Hertzian variables of contact load and sphere radius [1]. This method offers insight into the role of microstructure and microstructure- sensitive mechanical properties. It was hypothesized that tooth damage modes and patterns …

Role Of Nitric Oxide As A Modulator Of Platelet Dense Granule Release, Clifton Ford Frilot Ii

Doctoral Dissertations

Nitric oxide (NO) has been shown to suppress platelet activation, induce vasodilation, inhibit smooth muscle cell proliferation, and act against infection. Activated platelets generally have opposite effects from these. They secrete platelet-derived growth factor (PDGF), which stimulates smooth muscle growth, serotonin, which is a platelet agonist, and a number of agents that promote further platelet aggregation. However, activated platelets also produce NO through the enzymatic functions of the constitutive form of nitric oxide synthase (NOS). The primary functions of this capability are not yet completely understood. Due to its low molecular weight and high diffusivity, NO is quickly transported from …

Partial Characterization Of Extruded Collagen Tubes With Varied Material Deposition And Orientation Based On Rotation Rate And Linear Draw Speed, Richard Peter Hoppe

Theses

This study established protocols for extrusion of collagen tubes from an extruder made by the ZOKO Corporation of Czechoslovakia. Using a viscous collagen base material, collagen tubes can be formed with changes in rotation rates from 0 rpm to 260 rpm and linear draw speeds from 383 mm/min to 1270 mm/min with a constant extrusion rate of 50 cm²/min. These tubes, with further research and treatment, can be used for various medical applications including vascular implants and nerve conduits.

Post-extrusion, chemical crosslinking of the collagen increased the cohesiveness and mechanical integrity of the tubes. Microscopic photographs confirmed higher …

Generation Of Oxygen Microbubbles In A Microchannel With Crosscurrent Liquid Flow, Sung Sam Kim

Doctoral Dissertations

An alternative way of blood oxygenation is proposed by introducing small bubbles directly into the blood stream. To be used for blood oxygenation, the bubble should be small enough to pass through the capillary beds. To explore the feasibility of producing small bubbles, bubble formation phenomena in a crosscurrent liquid flow in a silicon microchannel were studied. Small orifices with 4 μm, 4.2 μm, and 6.6 μm hydraulic diameter were machined in a direction perpendicular to a trapezoidal channel that has a hydraulic diameter of 42 micrometers. These orifices were connected to three different chambers of 2.5 × 10−7 cm3, …

Evaluation Of 135- And 150-Degree Sliding Hip Screws, Kelly Blayne Crittenden

Doctoral Dissertations

Sliding hip screws are routinely used to repair Garden III femoral neck factures. This research seeks to better understand the influence of the hip screw angle on the performance of the fixation. The mechanics of fractured femurs repaired with 135- and 150-degree sliding fixation devices are explored using experimental, finite element, and analytical modeling. The experimental study involves testing of both intact and fixated femurs; the finite element work centers on two-dimensional models of intact and fixated femurs; and the analytical modeling explores the forces, moments and stresses in the fixation. The analytical model predicts that the screw will serve …

An Automated Approach For Comparative Analysis Of Interval And Heart Rate Variability, Taral Oza

Theses

Cardiovascular disease is the primary cause of death in the adult population. Half of these cardiac deaths occur as sudden death. Some of the parameters from the surface ECG recording (a noninvasive technique) carry important information and have special significance in research, as they are good indicators of diseases leading to heart attacks, sudden cardiac death and other similar cardiac problems. Measurement of QT interval variability and heart rate variability are two such parameters, which has received much attention of researchers.

An algorithm has been developed to measure and compare the two significant parameters, the QT interval variability and the …

Ultrasonographic Measurement Of Periodontal Attachment Levels, John Edward Lynch

Dissertations, Theses, and Masters Projects

Periodontal disease is one of the two major causes of tooth loss today, and has been associated with several systemic diseases, such as diabetes, cardiovascular disease, stroke, and adverse pregnancy outcomes. Unfortunately, the most widely used diagnostic tool for assessment of periodontal diseases, measurement of periodontal attachment loss with a manual probe, may overestimate attachment loss by as much as 2mm in untreated sites, while underestimating attachment loss by an even greater margin following treatment. Manual probing is also invasive, which causes patient discomfort.;This work describes the development and testing of an ultrasonographic periodontal probe designed to replace manual probing. …

Postural Balance And Acceleration Threshold Detection For Anterior Horizontal Translation In Diabetic And Non-Diabetic Elderly, Venkatesh Balasubramanian

Doctoral Dissertations

Slips and falls, and even the fear of failing, can represent a major medical and functional deterrent to living independently, especially among the elderly population. Various groups of elders are at known risk for falling including, but not limited to, those with vestibular dysfunction, those with low visual acuity including visual neuropathies, and those with peripheral neuropathies. The first two groups are fairly well studied, but the relationship between the level of peripheral neuropathy and extent of falling has received relatively less attention.

In this study, using sliding linear investigative platform for analyzing lower limb stability (SLIP-FALLS), the psychophysical thresholds …

Effects Of Compression Processing Parameters And Antioxidants On Molecular Degradation Of Biodegradable Poly-L-Lactide (Plla), Thomas J. Hannan Jr.

Masters Theses

The purpose of this research was to find a combination of poly (L-lactic acid), also known as poly-L-lactide or (PLLA) and antioxidants that would, together, produce a product whose degradation rate would be advantageous for use in biodegradable medical implants. Intrinsic viscosity tests were conducted on compression molded samples of PLLA that were molded at various processing parameters in order to find optimal parameters. The optimal processing parameters were found to be time 10 minutes, temperature 220°C, and pressure 1000 psi.

The molecular weight of PLLA sample was taken while pressure, time, and temperature were varied. As pressure increased, no …