Biomedical Engineering and Bioengineering Commons^™

Time Frequency Analysis Of The Electromyogram During Fatigue, Michelle Rene Davies

Theses

Spectral parameters obtained from the surface EMG signal have been used as indicators of fatigue during a sustained contraction. These same parameters have not been tested with the EMG signals obtained from fine wire electrodes. One such parameter is the median frequency which is known to decline with fatigue. A comparison was done between the median frequencies obtained from the surface EMG and those obtained from the fine wire EMG. The median frequencies from both types of electrodes decreased with time indicating that fine wire electrodes could be used to measure fatigue.

In addition, a new technique, time frequency analysis, …

Patient, Disease And Surgical Parameters In The Prediction Of Histologic Nodes And Recurrence Of Squamous Cell Carcinoma, Adolfo A. Ferreira

Theses

This research explores the impact of a variety patient, disease and lesion parameters upon the probability of post surgery recurrence of squamous cell carcinoma and the involvement of histologic nodes. It was found that parameters such as number of nodes, Lymph Vascular Space Invasion (LVS), figo stage, growth rate and host response as well as tumor thickness, depth of invasion and lesion size are good predictors. Other parameters such as cell type and condylomas were found to correlate minimally with recurrence and histologic nodes. Surgical parameters such as surgical margin and distance surgical margin were found to have poor correlation …

Three Dimensional Diaphragm Simulation Model For The Relationship Of The Tension, Pressure And Shape, Zhangming He

Theses

Weakness of inspiratory muscles is a major cause of respiratory failure. There are many clinical circumstances in which it may occur. The diaphragm is a major respiratory muscle. It has been difficult to quantify its shape, curvature and length.

To solve this question, a three dimensional diaphragm equation was derived on the, assumption that the diaphragm is only attached at its periphery to the rib cage and the abdomen is filled with fluid. Computer programs were developed to fit the equation to the diaphragm contours obtained from plane X rays.

The results indicate that the ratio of transdiaphragmatic pressure to …

In Vitro Testing And Evaluation Of Intraaortic And Extraaortic Balloon Counterpulsation Devices, Joseph V. Izzo

Theses

The primary purpose of this project was to develop an in vitro environment in which the intraaortic and extra-aortic balloon pumps could be tested and evaluated. This was done by modifying a mechanical heart simulator -- the pulse duplicator system -- to accommodate both devices, and developing a software system that could collect and process the data relevant to the operation of the two balloons.

Both counterpulsation techniques were tested in the pulse duplicator where the aortic pressure and flow data were collected. The software system then processes the data to calculate all of the parameters affected by counterpulsation.

While …

Reconstruction And Enhancement Of Medical Computed Tomography Images, Manoj K. Pattahil

Theses

The aim of Computed Tomography is to obtain information regarding the nature of the materials occupying precise positions inside the body. But due to errors in the projection data, which arise due to errors in measurement, beam hardening, missing data and noise, the reconstructed image has artifacts which reduces its diagnostic value. Thus the image obtained has to be processed to remove these artifacts and to improve the quality of the image. This is achieved by iterative reconstruction along with different post-reconstruction processing. Iterative reconstruction is done by repeating the process of projecting the image and creating new projection data …

Contour Extraction From Hvem Image Of Microvessel Using Active Contour Models, Manping Xiao

Theses

This thesis reports the research results on automatic contour extraction from high voltage electron microscope (HVEM) image of thick cross section montages of small blood vessels. The previous work on this subject, which was based on the conventional edge detection operations combined with edge linking, has proven inadequate to describe the inner structural compartments of microvessels. In this thesis, an active contour model (commonly referred to as "Snakes") has been applied to advance the previous work. Active contour models have proven themselves to be a powerful and flexible paradigm for many problems in image understanding, especially in contour extraction from …

Computer Assisted Molecular Modeling Of Thymidine Nucleoside Analog Inhibitors Of Hiv-1 Reverse Transcriptase, Mark A. Fisher

Theses

An active analog approach to receptor mapping was used to identify the three dimensional structural characteristics associated with a series of thymidine nucleoside analog inhibitors of HIV-1 reverse transcriptase (RT) that may be essential for their activity. Atomic substitutions at the 5 and 3' positions of nucleoside analogs confer global structural and electrostatic changes that result in either increased or diminished inhibitory activity. From a structural perspective, the activity differences can be attributed to the presentation of select atoms in three dimensional motifs that are common to all active compounds and absent or distorted in inactive/poorly active compounds.

The identification …

An Analysis Of A Custom Expanding Total Femoral Prosthesis With A Rotating Hinge Knee, Ramarao Gundlapalli, V. Gundlapalli

Theses

Osteosarcoma is the most common malignant bone tumor in the pediatric age group. This thesis presents the analysis of a total femoral prosthesis implanted in a 9 year old black male. The design includes a bipolar, expanding mid-shaft component, and a rotating hinge knee used in the reconstruction of the patient's right lower limb after surgical resection of the femur. The areas being analyzed are (i) the trochanteric attachment, (ii) the expanding component, and (iii) the rotating hinge knee. The stresses acting on the cables reconnecting the greater and lesser trochanter were determined for bipedal stance, single-legged stance, stance phase …

Optimization Of Flow In The Collecting Duct During The Concentrating Mode And The Diluting Mode In A Nephron Population Of Two Different Length With The Renin Angiotensin System And Adh Mechanism, Sivakumar Subramanian

Theses

Our present study is to find out how the short and long nephrons are interacting in the human kidney to adjust the flow in the collecting duct to have the maximum flow during the diluting mode and minimum flow during the concentrating mode. The best lengths for the short nephron and long nephron are calculated during the concentrating mode and the diluting mode by using the Newton-Raphson method. If one wants the kidney to perform only the above mentioned functions, a design criteria for an artificial kidney has been proposed. These studies have provided qualitative information regarding the concentrating mechanism …

Comparison Of Heart Rate With Chest Wall Vibrations, Kofi M. Arbuah

Theses

A study is done using a Microwave Interferometer as a computer-assisted non-invasive cardiopulmonary monitor. The Microwave Interferometer is used to record the mechanical vibration of the anterior chest wall by recording the velocity of the displacement of the chest wall. The objective is to first, record mechanical vibrations of the anterior chest wall at different heart rates, and second, attempt to identify the relation between heart rate and chest wall vibration.

The system uses two channels, the first signal produced by the Microwave Interferometer is a record of the velocity of the displacement of the chest wall caused by the …

An Experimental Investigation Of Wear Behavior Of Ultra-High Molecular Weight Polyethylene Under Sliding Motion, Elham Zand-Moghaddam

Theses

This project investigates the effect of sliding motion on the materials that are used as bearing surfaces of human total-joint replacement prostheses.

The tests are performed with a specially designed equipment based on pin-on-disk machine. The testing machine is designed and constructed to reproduce sliding motion, applied to spherical ended metal "Canine-Head" components such as dog hip acting on a flat polyethylene surface. The sliding motion is performed by applying different constant loads for 5,000,000 cycles. The tests are carried out with the wear specimen lubricated by deionized water.

The purpose is to produce delamination, which is the severe wear …

A Review Of Acetabular Prostheses For Total Hip Arthroplasty, Jennifer Anne Citarella

Theses

This study explores the evolution, design, and clinical progress of contemporary prostheses used in orthopaedic reconstruction of the socket of the hip joint. A literature search was performed to study acetabular implants, as used in total hip arthroplasty. The history of the design of these implants is chronicled. Next, the anatomy of the acetabular region and the surgical technique performed to replace the hip socket are presented. A comprehensive discussion of the design features, rationale, and clinical results for commercially available cemented and cementless prostheses follows.

Hydroxyapatite, a bioceramic which has just recently been approved for applications in total hip …

Study Of Emg Frequency Behavior, Mark Steven Fiedorowicz

Theses

It has previously been determined that the power spectral density of an electromyogram shifts towards lower frequencies over time during an isometric contraction. In this study the power spectral density curve was examined to see if changes would occur over a period of time as a subject walked on a treadmill at various speeds. The shapes of the power spectral densities recorded from the soleus shifted to the lower frequencies over time. The parameters associated with the curves showed trends. One of the parameters, zero crossing, demonstrated adaptation and fatigue in all four patients, for the first portion of the …

Computer Simulation Of Intracranial Hemodynamics During The Induction Phase Of Anesthesia, Gopinath P. Sundaram

Theses

The induction of general anesthesia is associated with severe hemodynamic compromises which, in turn, may cause acute elevation of intracranial pressure (ICP). Quantitative assessment of cerebrovascular responses arising from multiple mechanical and pharmacological interventions occurring in a short time interval require a large number of human studies which are difficult to perform. The purpose of this project is to evaluate the effect of various stimuli on the intracranial hemodynamics during induction using a mathematical model of cerebrovascular circulation.

A five compartmental model of the cerebrovascular system is used for our simulation. Autoregulation is modeled by adjusting arterial-arteriolar resistance in order …

A Multicompartmental Model For The Simulation Of Soluble Gas Exchange In The Lungs, Chitaranjan Varadhan

Theses

No abstract provided.

Blur Identification And Restoration Of Images Of Coronary Microvessel, Kuen Tak Wong

Theses

The objective of this research was to identify the blur characteristics of the blurred images of the rat coronary microvessel, and the information of the blur characteristics was used to restore the blurred images. The blur characteristics were analyzed by using the image power cepstrum. The Wiener filter was implemented to restore the images. There were two types of point spread functions proposed and studied for the restoration. They were: defocus blur PSF and motion blur PSF. The images were transferred from HP A900 system to an AVS workstation. The images were processed and manipulated by the AVS, and showed …

The Thermal Model Of The Rat Under Hemorrhagic Shock Hypothermia With Microwave Intervention, Liu Zhe

Theses

A whole body thermal model simulating heat distribution and temperature regulation in rats during hemorrhagic shock and during post-shock microwave core rewarming period was developed. An electrical circuit was used to simulate the thermal system and a software named PSpice? was used to analyze the circuit. The temperature regulation as the result of the simulation is demonstrated to match the measured temperature histories of rats in hemorrhagic shock and the microwave rewarming experiment.

The blood pressure drop and cardiac output decrease were considered in the simulation and the so called "set point temperature" was investigated in the model. Linear decrease …

Dynamics Of Blood Coagulation, Jie Gao

Theses

In this paper we present a new method to analyze whole blood coagulation dynamics. Using a PC-286 computer equipped with a DASH-16 AID board.

The row data from a SONOCLOT analyzer is amplified and digitized on the DASH-16 A/D board and stored in the PC-286 hard disk. The data is filtered through a digital Butterworth filter. The filtered data is then fit to mathematical relationship by the least square method. The coefficients which define the mathematical relationships are used to identify blood specimens with normal coagulation dynamics as distinguished from specimens with abnormal dynamics.

The digital filter and curve-fitting routine …

A Review Of Energy Storing Prosthetic Feet And Computer Aided Structural Optimization Of A Below-Knee Prosthesis, Poonam Gope Lalwani

Theses

Because people with physical disabilities have shown an interest in participation in sports, a new class of prosthetic feet known as "energy storing prosthetic feet" has been developed. These new developments in prosthetic foot design utilize energy storage and return to improve ambulation. This thesis reviews the design, materials, advantages and disadvantages of various energy storing prosthetic feet. Research studies, comparing gait in below-knee amputees using different prosthetic designs, can be applied to the design of prosthetic feet that are lighter, stronger and more reliable. Comparisions among these feet are reviewed in the context of functional capability and patient satisfaction. …

Fingerprint Pattern Recognition For Medical Uses, Feng You

Theses

The purpose of my research is to provide a method to automatically classify fingerprints into three subgroups: whorl, loop and arch, which can help medical scientists to study the relationship between fingerprint patterns and medical disorders. In the research, two different kinds of approaches were developed. The first one is performing pattern recognition in the frequency domain, which uses the feature of Fourier spectrum. That is, prominent peaks in the spectrum give the principal direction of fingerprint patterns. Using the above feature, we can obtain the principal direction of every subregion, after which the pattern of the whole image can …

A Study Of Pulsation Of Chest Wall Using Microwave Interferometer, Paul Zeno

Theses

The microwave interferometer is utilized to pick up vibrations of the anterior chest wall produced by the cardiac activity. The objective of this project is to find the causes of different peaks in the output of the microwave interferometer. The output of the microwave interferometer is recorded simultaneously with EKG and jugular pressure pulses. Eighteen subjects had their mechanical vibrations of the chest wall, EKG and jugular pressure pulses recorded. The processed interferometer data, when compared with EKG and jugular pressure pulses appear to have a close relation to the mechanical events in the cardiac cycle. Four peaks in the …

Computer Aided Finite Element Stress Analysis Of A Three Dimension Mandibular Bone Model Using I-Deas Software, Yixiong Xu

Theses

A three dimensional model of half of the mandibular bone, with 487 tetrahedra elements and 1,047 nodes, is established and analyzed by means of I-DEAS software. The masseter muscle is assumed to be 15° deviation from y-axis, and the Umetani boundary conditions are allowed to be varied. A 337 lb force was applied along the midline of the mandible to simulate a trauma force caused by the auto accident. The maximum principal stress is 18,400 psi and the minimum principal stress is -1,340 psi. Depending on the experimental results of dispalcement and maximum principal stress, the conclusions are drawn: 1) …

Quantitative Assessment Of Myocardial Oxygen Supply And Demand Using A Dynamic Model Of The Cardiovascular System, Badrinath R. Puranic

Theses

A quantitative understanding of the changes in coronary, pulmonary and systemic hemodynamic variables and their effect on myocardial supply and demand is important to the better management of anesthetic care of patients with impaired cardiac function. Animal studies have identified those hemodynamic factors that play an important role in determining the balance between oxygen supply and demand for the myocardium. These include myocardial contractility, left ventricular end-diastolic volume, systemic arterial pressure, systemic vascular resistance, and heart rate. The interactions of these factors are complex and their combined effects on myocardial oxygen supply and demand are difficult to predict a priori. …

Mathematical Model And Simulation Of The Progression Of Cutaneous T-Cell Lymphoma, Maria L. Agostinho

Theses

A simple mathematical model and simulation of the progression of cancer with particular emphasis on Cutaneous T Cell Lymphoma was investigated. The mathematical model consists of a set of differential equations that first satisfies the homeostasis levels of the different components present and second predicts the dynamics during a diseased or unhealthy condition. The simulation was done using a FORTRAN program for integrating the differential equations.

Simulation of the immune system is important in evaluating the usefulness of particular sorts of biologically targeted therapies and in selecting the most promising treatment strategies for clinical trials. In particular, the effects of …

The Acoustic Properties Of Human Femoral Bone, Mark Lacianca

Theses

Over the last decade, interest has grown in the use of the scanning acoustic microscope (SAM), with a single lens being used for both transmitting and receiving the acoustic signal. A major objective of this thesis was to determine if the transmission and ultrasonic techniques yield similar "quantitative" results, when measuring the elastic constants of human femoral bone. The transmission technique has been used since 1970 to yield values for the elastic properties of calcified tissue. Previously the SAM has been used as a qualitative tool, where an acoustic impedance map is produced. This map can show areas of bone …

Posterior Stabilized Knee Design Biomechanical Considerations, Donald E. Mcnulty

Theses

Numerous posterior stabilized knee systems are available for primary and revision total knee arthroplasty. Design of these systems requires an understanding of the articulating geometries and kinematic/kinetic biomechanical considerations of the normal knee. The findings for the normal knee are integrated into the design of a prosthetic system.

The natural femoral, tibial and patella articulating geometries are defined to enable subsequent kinematic and kinetic analyses. The articulating geometries are characterized from review of anthropometric studies of the tibiofemoral and patellofemoral joint.

The kinematic analysis of the natural knee defines knee motion in terms of rotation, adduction/abduction, range of motion and …

Effect Of 2,3-Butanedione Monoxide On Whole-Cell Potassium Channel Currents In Rat Single Myocytes, Youliang Zhou

Theses

The patch clamp technique is a simple procedure which can isolate ion channels on cell membranes. Our previous data have shown that 2,3-Butanedione Monoxime (BDM) could inhibit the calcium current by dephosphorylation of the channel. In this study, the effect of BDM on the potassium channels were investigated with the whole-cell recording method in single myocytes enzymatically isolated from the left ventricle of 3-4 months old rats. Superfusion of myocytes with BDM elicited a dose dependent decrease of the outward transient potassium current. BDM with concentrations of 5, 20 and 50 mM reduced the maximal peak potassium current by 7.3 …

A Computer Implementation Of A Multi-Neuron Expandable Network, Mary Ellen Ellen Aleksza

Theses

The primary goal of this thesis is to develop a small, expandable neural network that oscillates when presented with an appropriate stimulus. This model will be used in the future as a base to create larger networks. Future studies of these larger networks may be used in the simulation of neuronal activity such biological oscillators.

This thesis encompasses a study of neuron activity, neural networks, neuron models and biological oscillators. The focus of the thesis is the modification and expansion of a single neuron simulation into a simulation of an interconnected multi-neuron oscillatory network.

A single neuron model based on …

Wear And Friction Of Titanium Nitride On Ultra High Molecular Weight Polyethylene Under Oscillating Motion For Evaluation Of Use In Articulating Orthopedic Applications, David Scott Jacobson

Theses

Materials are a factor in the performance of articulating orthopedic implants. An oscillating tribometer is utilized to investigate mechanisms of wear and friction of TiN (titanium nitride) coated on Ti-6Al-4V (titanium) alloy against UHMWPe (ultra high molecular weight polyethylene). Three thicknesses of TiN coating (1.76 pm, 4.15 µm, and 10.5 µm) are used to evaluate the performance of each in UHMWPe wear reduction and coating integrity. An uncoated Co-Cr (cobalt chromium) coupon is used against UHMWPe pins for control purposes. Oscillations are carried out to 10 million cycles to discover and evaluate short- and long-term wear mechanisms. Mass differentials and …

Slow, Red-Green Counterphase (Parvo) And Fast, Black-White Magno) Snow In The Detection Of Scotomata In Primary Open-Angle Glaucoma, Rey Favis

Theses

No one knows why Primary Open Angle Glaucoma sufferers can detect their glaucoma induced blindspots by monocularly fixating on a mark in the center of a screen of television snow. An attempt was made to determine which of two pathways from retina to lateral geniculate nucleus is more involved in the detection of the blindspots. Previous studies demonstrated that the large diameter axon, magno cellular pathway is maximally stimulated by 30 Hertz high contrast black-white patterns. The small diameter axon, parvo cellular pathway is known from past research to be maximally stimulated by 12 Hertz red-green counterphase patterns. It was …