Engineering Commons^™

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. …

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 …

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 …

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 …

Ultrasonic Ranging System For Gait Analysis, Mu Wu

Theses

A new method of measuring range for gait analysis is described. The method is based on a coherent measurement of the phase shift of an ultrasonic signal as a function of range.

A prototype of the ranging system was breadboarded, tested, and found to have a relative accuracy of better than 0.5 mm over a range of 3 meters. The maximum range the system is at least 20 meters. The method used here is new and has not been found in the literature. Tt is demonstrated by experiments with a prototype system that can measure distance with a higher accuracy …

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 …

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 …

The Effects Of Twist On Pressure Through A Teflon Vascular Prosthesis, Steven Alfred Olivieri

Theses

A closed loop fluid system was developed which mimics the flow curve in the human circulatory system in order to test the effects of pressure drop and flow velocity on artificial arterial implants. This device consists of a piston pump connected to a microcomputer controlled servo-motor. Fluid (in this case distilled water) flows through transparent Tygon tubing to a test chamber. The prosthetic tube is placed in the fluid but is attached through a specially constructed chamber. The pressure across the implant can be measured for different conditions. System compliance was generated by using flexible tubing in the return loop …

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 …