Biomedical Engineering and Bioengineering Commons^™

Digital Image Restoration Using Power Spectrum Equalization Filtering Technique, Debdatta Sen

Theses

Digital deblurring of micro-circulatory images using both homomorphic and power spectrum equalization filtering are considered. An existing homomorphic filter was modified by changing filter parameters. This permitted an image with better contrast to be obtained. The power spectrum equalization approach consists of modeling and characterization of degradation and estimation of the power spectrum of the image using the Welch method. The restoration is considered from the point of view of spatial-frequency domain descriptions of images. Consideration is restricted to degradations arising from additive noise and spatially invariant linear blurring. The filter restores the power spectrum of the image to what …

Respiratory Impedances Computed From The Forced Oscillation Technique Using An Esophageal Balloon, Richard Thomas Fisler

Theses

The purpose of this investigation is to develop methodology for the standard measurement and physiological interpretation of lung resistance and compliance using non-invasive forced oscillations techniques and validating these results with standardized esophageal balloon techniques. Application of the forced oscillation technique with an esophageal balloon in place permits partitioning of the respiratory system into the pulmonary system which is of primary interest and the less clinically important chestwall system. Diseased lung states are induced in normal subjects by inhalation of a bronchoconstrictor. The total respiratory (pulmonary plus chest wall) and pulmonary impedances are interpreted using both a linear three element …

Three Dimensional Study Of Macromolecular Leakage Patterns Using Video Image Analysis, Nikhil V. Khimani

Theses

It has long been known that blood - tissue transport of macromolecules in the microcirculation is driven by diffusion. Although two dimensional models fit the experimental data well, the diffusion process is three dimensional.The objective of this research was to establish a three dimensional unsteady state mathematical model for intravascular transport of macromolecules, and suppoi t the theoretical establishment by experimental results.

Three dimensional diffusion of macromolecules through the interstitial space in the hamster cheek pouch was studied, with intravital fluorescence microscopy. After application of bradykinin, the movement of Fluorescein isothiocynate (F.I.T.C.) - labeled Dextrans of average molecular weight 150,000 …

Development Of A Novel Dentin Bonding Agent And Testing For Mechanical Properties, Mircroleakage And Toxicity, Sanjay V. Odak

Theses

In this study a dentin bonding agent based on Tolylene diisocyanatc with o chlorophenol as a blocking agent was tested. Bond strength with dentin was determined using a clinically relevant test method. A comparison was made using commercially available bonding agents and restorative resins. A simulation of microleakage around restorations was performed using a "Silver staining technique". Microleakage was quantified using digital image analysis, and a method was proposed to compensate for the loss of the third dimension during image analysis. Layer-by-layer curing of restorative, and an acid etching technique was used to improve bonding to dentin. The oral LD50 …

An Intelligent Computerized Pulse-Duplicator For The In-Vitro Evaluation Of Prosthetic Heart Valves, John F. Andrews

Theses

A computerized data acquisition system is presented for the in-vitro determination of the hydrodynamic performance of prosthetic heart valves. High speed data acquisition and ensemble averaging techniques are employed to minimize error and provide a standard for data collection and analysis across a wide range of simulated physiologic conditions. Processing algorithms automatically divide the cardiac cycle into phases based on landmarks in the pressure and flow waveforms, with minimal variability and without operator intervention. The contributions of valve resistance, regurgitation, ejection, leakage, and power loss to hydrodynamic performance are isolated for investigation. Phasic power loss analysis is reviewed as a …

Computerized Analysis Of Gastrointestinal Spike Burst Activity, Karthik Krishnan

Theses

This thesis describes a computer algorithm for locating gastrointestinal spike bursts. The algorithm also finds the the number of spikes within each spike burst, the average duration, and average amplitude of each spike burst. The algorithm was applied to the automation of the analysis of the Migrating Colonic Complex.

The algorithm detects the spike burst using threshold, time interval and frequency criteria. The computer program is implemented on a PDP 11/73 digital computer. The operation of the algorithm was tested on animal models to detect the spike bursts, before and after the inducement of certain drugs to alter the colonic …

Simulation Of Aids Patient Detoxification By An Extracorporeal Device And Related Experimental Studies, Mansoor Yusuf Kapadvanjwala

Theses

A simple numerical simulation of an AIDS patient detoxification by an extracorporeal device for the removal of virus has been designed. The mathematical model accounts for healthy white cells (W) attacking and destroying the virus (V), while at the same time the virus attacks and infects certain white cells. The infected white cells (W_i) serve as a site for viral growth, and finally the cell is lysed, releasing a large number of viruses in the blood stream. This model can be used to predict concentrations over a given period for the patient.

The device incorporates an antitwister mechanism …

Fetal Phonocardiography, Jeng-Kwan Lin

Theses

A reliable non-invasive tracking of the fetal heart rate from the maternal abdominal surface could be of significant diagnostic importance in the monitoring of pregnancies, not only for fetal heart rate assessment, but also for the observation of congenital cardiac malformations and transient difficulties during labor. Further, the fetal heart rate recording may be used to assess fetal heart rate variability in the antepartum period of gestation when it is not possible to obtain a fetal scalp lead electrocardiogram.

There are several methods being used to detect the fetal heart rate. Phonocardiography, abdominal electrocardiography and ultrasound cardiography are the three …

3-D Reconstruction Of Microvasculature From High Voltage Electron Microscopy (Hvem) Data, Pradip Kumar Paul

Theses

This is a new method for histoarchitectural and volumetric analyses of cell compartments of microvasculature with the use of a unique combination of computerized 3-D reconstruction and HVEM thick serial cross sections. The technology is potentially a reliable, simple, accurate and fast method. Pioneering work in this area was started by Todd et al. (Circ Res Vol :53 p 319 ;1983) basically using light microscopy, but supported by conventional ultrathin transmission electron microscopy. These techniques are important in that they promise to resolve controversies in terms of evaluating the occurance of hyperplasia and hypertrophy in small resistance vessels in various …

Morphological Analysis Of Microvessels Using High Voltage Electron Microscopy (Hvem), Ibm Personal Computer And 3-D Reconstruction Software, Wieslaw Slawomir Krajewski

Theses

The mesenteric arterioles (outer diameter < 100 µ) from a normotensive and a hypertensive dog were perfused in situ, excised, post-fixed and embedded in Spurr medium block. Thick serial cross sections (0.5 µ) of the vessels were obtained from hand formed mesas and placed on Formvar coated slot grids.

The cross sections were subjected to High Voltage Electron Microscopy (HVEM) and five or more electronmicrographs were taken to cover the individual cross sections. The prints of electronmicrographs were linearly enlarged (3X) and made into photomontages of sections. The membrane contours in the montages were traced on transparent overlays, producing polygons which in turn were traced on GTCO digitizing pad. All polygons were labeled, color coded and stored in IBM PC's filing system. The vessels were reconstructed from up to 100 whole cross sections and subjected to cell compartmentalvolume analysis. The reconstructed images can be …

Optimization Of The Design Of The Harrington Distraction Rod And Hooks, Margaret Ann Pisani

Theses

The Harrington Distraction Rod is presently attached to the spines of patients who suffer from scoliosis and vertebral fractures. The rod's purpose is to apply a distractive force to the scoliotic curve in an attempt to reduce its severity. In fractures this rod is implanted to reduce the fracture and increase the stability of the spinal column. Harrington distraction rods are also inserted in order to give mechanical support to the spinal column.

Presently the Harrington Distraction Rod, manufactured by Zimmer, is one—quarter inch in diameter and made of 316L cold—worked stainless steel. The proximal end of the rod consists …

The Effect Of Platelet Activating Factor On Leukocyte Adhesion To The Post Capillary Walls And Developing Dose Response Relationships, Michael Francis Fitzpatrick

Theses

Blood circulation at the microcirculatory level plays an important role in the inflammatory process. Adhesion and emigration of white blood cells are among the major microcirculatory responses to inflammation. It has been recently suggested that platelet activating factor (PAF) may be a significant mediator in the local inflammatory response. This research was undertaken to characterize and quantitate the effects of PAF on the adhesion of white cells to the wall of postcapillary venules of 7-80um diameter.

The hamster cheek pouch microcirculation was used as a model for microcirculatory dynamics and was prepared for both bright field and fluorescent intravital microscopy. …

Fibrin Glue For Spilt-Thickness Skin Grafts And Microsurgical End-To-End Arterial Anastomoses In Live Rats, Susan Diane Drastal

Theses

Fibrinogen and thrombin were combined to make a "glue" for adherence in microvascular anastomoses and split-thickness autologous skin grafts in rats. The powdered human fibrinogen and bovine thrombin were mixed with sterile water and each applied drop-wise through separate syringes in equal concentrations. A gelatinous clot formed in 10 seconds, and was completely coagulated in 45 seconds. In part I, one-half of the group had their grafts sutured, and one-half had their grafts glued in place.

In part II, microvascular arterial anastomoses were performed. Group I had their arteries reanastomosed using sutures only; group II had their arteries reanastomosed by …

Characterization Of Pulse Duplicator Model For Testing Of Heart Valves, Pankesh Nilkamal Kadam

Theses

The design and development of a pulse duplicator system for testing of prosthetic valves is described. The performance characteristics were evaluated by computing the input impedance of the system from the measured pressure and flow signals for different simulation configurations. The study has been further extended to determine the feasibility of evaluating the cardiovascular status of a patient after major open heart procedure or in state of shock.

Built on hydrodynamic principles, the model allows for a wide range of heart rates, flow rates and mean pressures to be simulated. The artificial circulatory system used as a load to the …

A Mathematical Model For The Isometric Contraction Of Smooth Muscle On The Basis Of The Phosphorylated Myosin Regulation Process, Joseph J. Kocinsky

Theses

A mathematical model was proposed for the isometric contraction of smooth muscle (i.e., vascular, urterine, & gastrointestinal) that accounts for the experimental observations on tension transients and pCa²⁺-tension curves. The model is based on the elementary reaction kinetics involved in the process; it uses the Ca²⁺-dependent myosin phosphorylation regulatory mechanism in its interpretation. The model is composed of four parts : (a) the activation of myosin light chain kinase; (b) the phosphorylation of myosin light chains; (c) the actin-myosin Mg²⁺ATPase cross-bridge reaction cycle; and (d) the development of isometric tension. The interaction of the …

The Non-Contacting Surface Area Assessment Of Burn Wounds Using Computer Imaging Methods, Sarmishtha Meeta Rath

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 body affected by burns, measured by the percent total burn surface area, is of critical importance in evaluating fluid replacement amounts and nutritional support during the first 24 hours of postburn therapy. A simple technique has been developed which facilitates the measurement of burned areas non-invasively. Directly measuring burn surfaces yields quantitative results which can be used in assessing the extent of burns, monitoring the healing progression …

Mathematical Modelling Of The Simultaneous Diffusion Of Egta And Caegta And Ca2+ In A Two-Compartment System Representing Skinned Smooth Muscle, Roderick Jon Hausser

Theses

Smooth muscle strips "chemically skinned" with Triton X-100 represent a two-compartment system consisting of the extracellular space (ECS) and the cytosolic space (CS) bounded by the permeabilized plasma membrane. Free [Ca²⁺] in such systems must be controlled with sufficiently high concentrations of Ca-buffers (EGTA). The presence of Ca-buffers, however, will oppose and delay any changes in [Ca²⁺] in both compartments. We have developed a model describing the simultaneous diffusion of Ca 2+ , EGTA and CaEGTA between bath and ECS, and ECS and CS and the chemical reaction between ligand and metal species in each compartment. …

The Effect Of Systemic Arterial Pressure On Microvascular Flow And Transcapillary Exchange Of Macromolecules In The Hamster Cheek Pouc, Govind Mohanlal Gawdi

Theses

Microvascular flow velocities and transport of macromolecules were studied in the hamster cheek pouch under control and acute high arterial pressure conditions, with or without topical (local) application of the vasodilating agent, bradykinin. Mean arterial pressures of 130-160% control were attained by intravenous renin infusion. The microcirculation of the cheek pouch was studied using intravital microscopy. Areas with arterioles and venules were recorded on a videotape for later analysis of red cell velocity, using an RBC tracking correlator, and vessel diameter using a video shearing monitor.

In addition, vascular permeability to macromolecules was studied in the hamster cheek pouch vascular …

Preparation And Testing Of Novel Blocked Isocyanate Dental Adhesives Based Upon Hydroxyhexylmethacrylate, Gururajan Rao

Theses

In this study dental adhesives synthesised from TDI/HHMA/pentaerythritol, with either of the blocking agents namely eugenol, o-methoxyphenol, p-cresol or o-chlorophenol were tested. Bond strengths in dentin as influenced by spacer molecules were tested. Comparison studies to determine this were performed using the same blocking agents and TDI/HEMA/pentaerythritol. The effects of i. post-extraction time and ii. dentin depth on bond-strengths were tested using two monomers: o-methoxyphenol/ TDI/HEMA/pentaerythritol and p-cresol/TDI/HEMA/pentaerythritol 1. From teeth recently extracted (2h) vs dentin aged from one to six months 2. From dentin cut from three different levels within the tooth.

The prepared dentin-adhesive samples were stored in …

Effects Of Physical Exertion And Caffeine Ingestion On Mental Performance, Alireza Shafiei

Theses

Stresses in man-machine systems can be broadly classified as (1) physical and (2) mental. Both types of stresses generate some kind of response in the human body. These responses could be physiological (quantitative) or behavioral (qualitative). While the physical stresses mostly create physiological changes, mental stresses may cause physiological and/or behavioral changes. The purpose of this study is to investigate such influences, and try to determine if stimulants such as coffee have any effect on people's ability to perform tasks involving a combination of physical and mental elements.

An attempt has been made to describe an interrelationship between physical exertion …

In Vitro Comparative Hydrodynamic Study Of Heart Valve Bioprostheses Under Accelerated Fatigue Conditions And Under Physiological Conditions, Mario Cincinat Iosif

Theses

The present study involves the use of an accelerated fatigue testing system*, and a pulse duplicator (heart simulator)*, to evaluate the hydrodynamic characteristics of cardiac bioprostheses.

The hydrodynamic performance of these prosthetic valves is compared when tested using each machine, in order to assess the determining conditions that exist for each case, and try to correlate them.

Pressure drop and pulsatile flow across valves are measured, using a real-time on-line data acquisition system, which includes, in addition to the fatigue tester and the pulse duplicator, a DC amplifier, an analog-to-digital converter and a digital microcomputer. Special acquisition software has been …

Microcomputer-Based System For The Measurement Of Facial Swelling, Michael Guy Demuth

Theses

The measurement of facial swelling after oral surgery can indicate the effect of anti-inflammatory drugs. A mechanical device was interfaced to a microcomputer to allow faster calculation of swelling. The mechanical system first established X and Y coordinates on the face. A feeler arm traced out the facial contours and two linear variable differential transformers (LVDTs) related X and Y displacements to voltages which were fed into a microcomputer via an A/D converter. Three BASIC programs were written which facilitated the analysis of patient swelling. MEASUREMENT stored the X-Y voltages from the LVDTs in a patient disk file. CALCULATION filtered …

Spectrum Analysis And Real-Time Analysis Of Electroencephalograms, Suzanne Hesook Won

Theses

The analysis of the EEG background waveform is studied by two techniques, spectrum analysis and real-time analysis. The spectrum analysis is performed by using Fast Fourier Transformation (FFT) on a segment of the signal. The resulting signal is classified into different band types such as delta, theta, alpha and beta, to see the power in each band, and the magnitude of the power on the left and right side if the brain is evaluated for asymmetry. The mean power frequency shows the frequency where the maxinum power exists in each band type. This type of analysis provides overall information of …

Two Dimensional Diffusional Model For Leakage Of Macromolecules In The Interstitial Space, Suthiluk Dumrongsiri

Theses

Two dimensional diffusion of macromolecules through the interstitial in the hamster cheek pouch was studied with intravital fluorescence microscopy. After topical application of Bradykinin, the movement of Fluorescein isothiocyanate (FITC)-labeled dextrans of average molecular weight 150,000 daltons (Dextran 150) was recorded on videotape which latter was played back frame-by-frame for analysis by digital image processing. Leakage of macromolecules in response to topical application of Bradykinin occurs at discrete leakage site in post caplillary venules of 15-25 um diameter, rather than in the capillary themselves. A mathematical model of two dimensional convection plus diffusion was used to simulate the macromolecule transport. …

Automated Eeg Spectrum Analysis System, Marinela C. Laguna

Theses

A computer system has been designed to acquire EEG data from monkeys and to perform the spectral and statistical analysis. The system is capable of processing two channels simultaneously, acquire 64 Kbytes of EEG data for each channel on floppy disk, do the spectrums and averages of the spectrums, and calculate the histogram amplitudes of 13 frequency bands in a range of 0-71.1 Hz.

The software gives the user a lot of choices with respect to data acquisition and processing. The relative spectral power differences between "no-drug" and "drug" experiments give information about the drug effects on the central nervous …

Preparation And Testing Of Blocked Isocyanate Dental Adhesives, George W. Sweitzer

Theses

Three monomers were used in this study. Two were prepared from 2,4-toluene diisocyanate (TDI),2 hydroxyethyl methacrylate (HEMA), and either o-methoxyphenol, or o-chlorophenol. The third monomer was prepared from pentaerythritol, TDI, HEMA, and p-cresol.

These monomers were bonded to dentin slices, and then combined with an adhesive copolymer consisting of methyl methacrylate and poly(methyl methacrylate). This mixture was polymerized at room temperature by addition of N,N-dimethyl-p-toluidine, and benzoyl peroxide. This adhesive copolymer was applied to monomer coated slices of dentin, and to aluminum coupons already fixed in a jig. The monomer-coated dentin slices (treated with the adhesive copolymer) were then placed …

Computer Simulation Of The Human Hypophysial-Ovarian System, Robert Charles Blencowe

Theses

In order to more adequately simulate the human pituitary-ovarian cycle further refinements were made to the original Bogumil and Feng computer models. This involved the inclusion of equations which mathematically describe the peripheral conversion of prehormones and a subroutine showing the effect of plasma proteins, TeBG, CBG, and albumin on the total concentration of estradiol, progesterone, testosterone, androstenedione, dehydroepiandrosterone and estrone.

Once the models were functioning properly, values for the normal state and for the disease condition, Polycystic Ovary Syndrome (PCO), were obtained. In most cases there exists good agreement between the results reported in the literature and those generated …

Computer Simulation Of The Respiratory System, Bruce Diner

Theses

The respiratory system was simulated utilizing a series of three models, each more complex than the previous. The first model simulated the respiratory system as a two compartment model driven by carbon dioxide concentration. The second model, also a two compartment model, simulated periodic breathing while the third model is a three compartment model and simulates acid-base balance disturbances.

In this study, the effects of hyperthyroidism and respiratory center depression on respiration premeasured utilizing the models to obtain data and then compare the results to known physiologic data.