Biomedical Engineering and Bioengineering Commons^™

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 …

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 …

Image Deblurring For Visualization Of Coronary Microcirculation, Kaijun Wang

Theses

Blurred images of the rat coronary microcirculation have been obtained and processed. Heart motion, blood flow and noise cause the blur of the images. The objective of this thesis work was to study the effects of these factors on image quality and assess several models for image deblurring. The Wiener Filter and the Powei Spectrum Equalization Filter were implemented and were added to the existing image processing software. The images obtained after the application of these filters showed significant improvement over the original blurred images.

Three Dimensional Visualisation Of Tmj Anatomy Using Mri Techniques, Mythreyi T. Krishnaswamy

Theses

The best assessment of temporomandibular joint (TMJ) can only be done by the scanning the jaw and getting an image without invivo analysis which causes patient discomfort. There have been innumerable efforts to get the best view using CT techniques for three dimensional visualisation. But very few have done work using MRI techniques.

The TMJ is an integral part of the jaw and helps in mastication and biting. Since the joint is a hinge sliding articulation any dislocation causes immense pain and discomfort.

To get a better assessment of the TMJ, MRI techniques have been used for data acquisition. The …

Automated Eeg Analysis And Spike Detection, Walter Vanderschraaf

Theses

EEG analysis of epileptic patients is extremely time consuming. Patients are monitored up to 36 hours at a time. The neurologist must visually review stacks of EEG records to determine whether they contain epileptic or artifactual activity. This process is very subjective and can vary from one neurologist to another based on his or her training and experience. The neurologist is only human and may tire or lose his or her concentration. Automated EEG analysis can efficiently reduce the amount of data and time involved in analysis. It is also more consistent and objective than human analysis.

The main objective …

Calcium Channel Dynamics In Hippocampal Neurons : Simulation And Physiological Studies, Prasad D. Jasthi

Theses

Mathematical modelling and computer simulations of neurons was presented by various researchers in the past. Computer simulations provide a time efficient and cost effective method to obtain required information about the physiological system. The objective of this project is to study the kinetics of calcium channels in hippocampal neurons. In an attempt to study the calcium channel activity we have developed a mathematical model for the CA3 region of the hippocampus and have analysed the calcium current noise obtained from the physiological recordings. The Simulation results had reproduced the action potential and activities of sodium and potassium channels, but did …

Bio-Mechanics Of The Hip Joint And The Engineering Considerations In The Treatment Of Unstable Intertrochanteric Fractures, Manoj D. Nene

Theses

Numerous previous attempts have been made to determine the magnitude and the direction of forces acting on the hip joint. The mechanism of femoral neck fractures and the frequently occurring failure of its internal fixation has led engineers to analyze the forces involved. An unstable intertrochanteric fracture is one which lacks continuity of the bone cortex on the opposing surfaces of the proximal and digital fragments. A mathematical model is created in this study to examine the 135° and 150° nail plate. The results give an approximate estimation of stresses on the two plates. A 3D finite element model of …

Deconvolution Applications In Arterial Dynamics, Shanthi Ganesan

Theses

This thesis deals with the computation of the Arterial Impulse Response Function by deconvolving aortic pressure and flow signals in time domain. Several methods have been developed in the past to obtain a solution for the convolution integral. These are (1) Transform method, and (2) Numerical Approximation methods : a. Conventional method b. Relaxation methods.

These methods have been applied in the past to the RC network model and it was found to work well. In this thesis, the methods are applied to data from more realistic models and also on data obtained from dogs. The model considered is a …

A Biomechanical Analysis Of Three Humeral Fracture Fixation Systems, Alina Michelle Waite

Theses

Often, humeral fractures requiring internal fixation can be a challenging orthopaedic procedure. Each method of treatment possesses clinical and biomechanical advantages and disadvantages. Rigid plate fixation is highly successful in treating a large variety of long bone fractures. Nevertheless, excessive soft tissue dissection is necessary, and vascular and neural anatomy of the humerus can make plate application and removal difficult. An intramedullary nail offers a relatively simple procedure, thereby reducing these anatomical concerns. However, rotational instability at the fracture site is a common complication with a conventional intramedullary nail. Thus, a study was conducted to evaluate a new interlocking intramedullary …

An Approach To Improving The Antithrombogenesis Of Pneumatic Diaphragm Artificial Ventricle : Fabrication And Design Considerations, Hui-Sun Wang

Theses

Thrombus formation is one of the major problems in artificial heart development and its clinical applications. In order to improve the antithrombogenesis in the artificial ventricles, three aspects of investigation have been done in the laboratory.

1] the surface features and the surface defects on specially prepared samples made of polyurethane and silicon rubber were studied and analyzed by scanning electron microscopy ( SEM ), light microscopy and KEVEX Feature Analysis for understanding and controlling the blood contacting surface.

2] the polyurethane blood contacting surface with smooth surface fabricated by solution cast process, the material treatment, and the fabrication procedure …

Adaptive Filter Application In Fetal Electrocardiography, Xueqiang Zhou

Theses

A hybrid adaptive algorithm for cancelling the maternal electrocardiography (MECG) component in abdominal fetal electrocardiography(FECG) is described. This algo rithm combines the advantages of the orthogonal algorithm which was developed by Reichert(1977) and the multiple reference noise cancelling adaptive algorithm which was developed by Widrow(1975).

The simulating experiment was taken to test all of these three algorithms. It demonstrated that all these three algorithms can cancel the abdominal component of the maternal ECG with three limb lead ECG signals. and the hybrid algorithm is at least as effective as each other algorithm alone. In this experiment, the abdominal ECG signal …

Oscillatory Potentials Model And Parameter Identification, Huizhong Pan

Theses

Two mathematicals model are presented for the oscillatory potentials of the electroretinogram. These models represent the oscillatory potential in terms of sets of parameters whose values may provide information of diagnostic value.

The test setup and protocol for obtaining the oscillatory potentials are described, as well as the data processing including acquisition up to identification of the model parameters.

Data from eight subjects, five normals and three diabetics, were used to evaluate the two models. These preliminary test results show a marked difference in the values of some of the model parameters between normals and diabetics.

Image Enhancement And Analysis Of Leukocyte Adhesion, Yee-Ruh Lin

Theses

The image of leukocyte adhesion to microvascular walls in the isolated rat perfused heart model has been observed and processed. Some of the fluorescent labeled leukocytes are barely visible due to microscope focal plane and the motion of objects. The purpose of this thesis is to extract leukocyte from the image of the experimental data using image enhancement and analysis (segmentation) techniques and develop a program to handle automatically counting of leukocytes in a predefined scene.

Eeg Data Compression, Yun-Chu Wu

Theses

This paper presents two different ways to compress EEC data-direct data com pression and a data transformation technique. The Adaptive Delta modulation and Huffman coding are used in the former method to predict or interpolate the data. Linear orthognal transformation algorithms are used in the latter method to detect and reduce the redundancies of the data by analyzing the spectral and energy distribution. Each method is implemented by programming the computer. The experimental results of their efficiencies and errors with different requirements and under different situations are compared and discussed. By comparing the EEC data compression degree and normalized square …

Burn Wound Healing Evaluation By Infrared Imaging, Shang-Yuan Chen

Theses

Infrared imaging is a pictorial method of temperature representation. Its advantage in the treatment of burns is that it is a non-invasive, safe and reliable method for estimating the area, temperature and depth of burns. An Imaging Burn program was developed for comparing changes in burn area in response to treatment with time. The program proved itself capable of determining the surface area of simulated lesions on the skin of human volunteers to within an error of 1.6 percent. The size and temperature of burn lesions in patients was recorded. First degree burns were warmer than surrounding areas of normal …

The Application Of Adaptive Step-Size Control In The Numerical Simulation Of Calcium Release In Vascular Smooth Muscle, Michael John Sydor

Theses

An algorithm for the adaptive control of numerical integration step-size is developed and implemented for the simulation of a three compartment model for Vascular Smooth Muscle. The three compartment model accounts for the simultaneous diffusion of Ca, ⁴⁵Ca, EGTA, Ca-EGTA, and ⁴⁵Ca-EGTA, and is an extension of a two compartment model by Diecke for the simultaneous diffusion of Ca, EGTA, and Ca-EGTA. The addition of the third compartment is to account for the presence of the Sarcoplasmic Reticulum which stores the calcium needed for contraction and is the primary regulator of calcium in the VSM cell. The SR …

Experimental Study On Filterability Of Leukocytes, Qi Wang

Theses

The filterability of leukocytes treated with A23187, Cytochalasin B, PAF and FMLP and pumped through 5 µm polycarbonate filters at a constant flow rate was examined. The concentration of the four agents was systematically varied. The filtration pressure was continuously recorded for data analysis. The pressure-time curves generally showed multiphasic components, following a small jump step at the beginning of the filtration process. The pressure rise was initially fast (initial faster increased phase, IP) and then rose more slowly (later slower increased phase, LP). The leukocytes treated with A23187 showed increased IP and higher LP values; those which were treated …

Ligament Reconstruction : A Biomechanical Cadaveric Test Of Autogenous Repairs And The In Vivo Evaluation Of Synthetic Scaffold Materials, Anne Marie Daly

Theses

The knee joint is the largest and one of the most complex joints in the human body. The anterior cruciate ligament (ACL) is one of the major intra-articular ligaments responsible for controlling and guiding the knee through most of its range of motion and its rupture alters normal joint mechanics.

One objective of this thesis was to determine if two autogenous tissue ACL reconstruction methods were biomechanically equivalent. The first method using the central one-third of the patellar tendon has been used clinically since the early 1960s. The second method utilizes portions of both the semitendinosus and the iliotibial band. …

Mathematical Modeling And Simulation Of The Progression Of Aids, Anju H. Nagpal

Theses

Acquired Immunodeficiency Syndrome (AIDS) caused by Human Immunodeficiency Virus (HIV) is a pernicious disease acknowledged as a world health problem. One of the major issues in the study of AIDS is understanding the manifestation and the progression of the disease following the transmission of HIV. Unfortunately, the present state of biological knowledge does not yet give us a reliable means of evaluating these phenomena. A simulation approach is, therefore, extremely useful in predicting the various phases of the deteriorating physiological status of the patient. In the present study we have focused on the development of a mathematical model of the …

A Comparison Of Integrated And Differential Estimates Of Flourescent Intensity Profiles Using Digital Video Image Analysis, Langfang Wu

Theses

The dynamics of macromolecular transport across microvascular walls in the hamster cheek pouch have previously been studied by other investigators using fluorescence intravital microscopy. Fluorescein Isothiocyanate labeled Dextrans (FITC-Dx) of 20,000, and 70,000 molecular weight (FITC-Dx-20 and FITC- Dx-70) were used as macromolecular probes. Values of fluorescent intensity were previously recorded on videotape as a function of distance perpendicular to leaking vessels over a period of about 2.5 hr to allow for tracer equilibration in the interstitial space. In this study, these videotapes were played back frame-by-frame and 215x130-pixel windows around each leaking vessel were selected for further analysis of …

Three Dimensional Finite Element Analysis Of A Tibial Ankle Prosthesis, Harrison Philip Crowell Iii

Theses

In this study, three dimensional finite element analysis is used to evaluate and compare partially and fully porous coated tibial components, of an ankle prosthesis, implanted in the distal tibia. The geometry of the distal tibia is determined from measurements of cross sections of a human tibia. From the measurements, solid models of the cancellous and cortical bone are created. A solid model of the tibial component is created and positioned in the solid model of the bone. From the solid model, a finite element model is created for the partially coated case and for the fully coated case. Each …

Biomechanical Analysis Of The Acetabulum And Acetabular Prothesis By Three Dimensional Finite Element Analysis, Mitchell J. Palmer

Theses

A biomechanical analysis modeling methodology of the acetabulum and acetabular prosthesis using three dimensional finite element analysis is presented. A simplified pelvis model is utilized which will yield accurate bone/component interfacial stresses. The SDRC IDEAS software program was used to perform the associated operations. Model generation of the simplified pelvic model and cup, finite element subdivision; material properties, restraints and load modeling are detailed. The model is comprised of 429 isoparametric elements in the simplified pelvis portion and 633 elements in the cup portion. Materials properties and loads are from the literature. The modeling methodology offers the advantages of determining …

Three-Dimensional Stress Analysis Of The Femoral Midshaft Utilizing Computed Tomography And Finite Element Analysis, Peter F. Marion

Theses

Recent advances in computer technology have provided both the medical community and biomedical engineers with a method for noninvasively evaluating the internal structure in a way not previously possible. A three-dimensional finite element model of a midshaft section of the femur was generated, utilizing Computed Tomography scan data. The CT scan data file was introduced into an edge-detection algorithm and a file of geometric edge data was generated. This edge data was introduced into a solid modeling Computer-Aided Engineering software package to produce a three-dimensional solid model. A mesh generation procedure was then used to create a three-dimensional finite element …

Investigation Of The Fluid Dynamics Of Bioprosthetic Heart Valves, Carol A. Calta

Theses

There is a strong connection between altered arterial blood flow and vascular disease. The presence of disturbed flow and/or excessive turbulence is an indication of an abnormality within the cardiovascular system. The examination of cardiovascular fluid dynamics provides insights into the working of the cardiovascular system and ways to improve the design of implantable bioprosthetic valve designs. This investigation examines the fluid flow of arterial systems, and ways to apply this knowledge to the valves implanted into patients.

This thesis involves an investigation of the testing of bioprosthetic valves within simulated left heart flow loops. These systems include pulse duplicators …

A Comparison Of The Fracture Toughness, Hardness, Impact Strength, And Thermal Expansion Of Two Dental Porcelains, Nancy Maignon

Theses

Dental Porcelains are known to be very brittle materials. Ongoing research is being undertaken to obtain a porcelain of optimum strength. A recent development in this field is the new porcelain Optec HSP.

In this comparative study, a series of mechanical test were performed on both Optec HSP and Ceramco II.

An indentation technique was used to calculate the hardness and fracture toughness, the Izod method with a 1 ft-lb pendulum was used to obtain the impact strength, and the thermal expansion was calculated with the Dupont thermal analyser.

For each material, a sample size of five and twenty specimens …

A Non-Invasive Technique For Burn Area Measurement, Jong-Daw Yu

Theses

The need for a reliable and accurate method for assessing the surface area of burn wounds currently exists in the branch of medicine involved with burn care and treatment. The percentage of the surface area is of critical importance in evaluating fluid replacement amounts and nutritional support during the 24 hours of postburn therapy. A noninvasive technique has been developed which facilitates the measurement of burn area. The method we shall describe is an inexpensive technique to measure the burn areas accurately.

Our imaging system is based on a technique known as structured light. Most structured light computer imaging systems, …

The Evaluation Of Polysulfone Composites As Structural Implants In Orthopaedic Surgery, Howard L. Scalzo

Theses

Two polysulfone composites were evaluated to determine their use as structural implants in orthopaedic surgery. The first composite, carbon fiber reinforced polysulfone (C/PS), was evaluated for environmental degradation in an in vivo and in vitro study. The C/PS composites were implanted subcutaneously in the abdomen of rabbits for the in vivo study and immersed in saline solution at 32° C for the in vitro study. The second composite, hydroxylapatite coated polysulfone (HA/PS), was evaluated for bone ingrowth in an in vivo study, and for attachment strength between the HA and the PS in an in vitro study. Also, two surface …

In Vitro Biocompatibility Study To Determine The Synergistic Effect Of Components For An Artificial Bone Graft Material, Levelle Elise Burr Alexander

Theses

A composite bone graft material which can induce or promote new bone growth has potential orthopaedic applications in the repair of bone defects or the stabilization of surgically implanted devices. This material should be biocompatible, have good handling properties, promote osteoinduction and/or osteoconduction and have a good shelf life. Demineralized bone matrix and bone morphogenetic protein have been demonstrated to promote osteoinduction in vitro and in vivo.

This in vitro study examined the inductive ability of an osteoinductive protein, bone morphogenetic protein, when absorbed on non-active devitalized bone matrix. In culture, fetal rat muscle was grown on powdered rabbit demineralized …

Red Blood Cell Deformability Testing By Using A Rheological Method, Zhenglei Ma

Theses

A rheological model of blood has been used for testing red cell deformability. The result of the testing is characterized by five parameters of the model. We suggested that the rheological behavior of blood is affected by red cell deformability. The result of the parameter C of the model, which is the kinetic rate constant of the structural breakdown of rouleaux into individual erythrocytes induced by shearing, from decreased red cell deformability group higher than that from normal control group lead to a criterion for separating normal subjects from decreased red cell deformability. The easy experiment method of using whole …

Survival Rate Study Of Intrashock Versus Postshock Microwave Rewarming In Rats Subjected To Hemorrhagic Shock, Hani M. Patel

Theses

In search for a more effective treatment for rewarming of profound accidental hypothermia, a comparative survival rate study was conducted of intrashock versus postshock microwave rewarming in rats subjected to hemorrhagic shock. In an anechoic chamber, rats were illuminated with 50 Watts of continuous microwave power supplied by a 915 MHz microwave generator. This frequency corresponds to a free-space wavelength of about 33 cm. The incident-power density was calculated to be about 8.5 mW/cm2, and the whole-body specific absorption rate (SAR) was calculated to be 14.5 W/kg.

The microwave postshock group showed a significantly higher post shock survival rate than …