Biomedical Engineering and Bioengineering Commons^™

Electroencephalography: Subdural Multi-Electrode Brain Chip, John E. Rosenstengel

Theses and Dissertations

In October 1995, a CMOS brain chip consisting of two 8 x 17 multiplexed sub-arrays designed to measure electrical potentials at the cortical column level, was implanted on the somatosensory cortex of a laboratory rhesus monkey. Electroencephalograph (EEG) and averaged evoked response (AEG) data were taken over a period of 40 minutes. The brain chip was replaced with an identical chip, and data were again taken for 40 minutes. In both instances AEG signals of approximately 150 µV_pp were recorded. Additionally, the first implanted chip recorded three phases of data: (1) AEG; (2) large clock noise (during a period …

Computer-Aided Diagnosis Of Mammographic Masses, William E. Polakowski

Theses and Dissertations

A new Model-Based Vision algorithm was developed to find possibly cancerous regions of interest (ROIs) in digitized mammograms and to correctly identify the malignant masses. This work has shown a sensitivity of 92 percent for locating malignant ROIs. The database contained 272 images (12 bit, 1OO microns) with 36 malignant and 53 benign mass images. Of the 53 biopsied benign cases, 74 percent were correctly classified. The Focus of Attention (segmentation) Module algorithm used a physiologically motivated Difference of Gaussians (DoG) filter to highlight mass-like regions in the mammogram. The Index Module labeled the regions by their hypothesized class: large …

Detection Of Clustered Microcalcifications Using Wavelets, Donald A. Mccandless

Theses and Dissertations

An automated method for detecting microcalcification clusters is presented. The algorithm begins with a digitized mammogram and outputs the center coordinates of regions of interest (ROIs) that contain microcalcification clusters. The method presented uses a 12-tap Least Asymmetric Daubechies (LAD12) wavelet in a tree structured filter bank to increase the signal to noise level of microcalcifications. The signal to noise level gain achieved by the filtering allows subsequent thresholding to eliminate on average 90% of the image from further consideration without eliminating actual microcalcifications 95% of the time. A novel approach to isolating individual calcifications from background tissue through non-stationary …

Computer Aided Detection Of Microcalcifications Utilizing Texture Analysis, Ronald C. Dauk

Theses and Dissertations

A comparative study of texture measures for the classification of breast tissue is presented. The texture features investigated include Angular Second Moments, Power Spectrum Analysis and a novel feature, Laws Energy Ratios. The texture study was accomplished as part of the development of a Model Based Vision (MBV) system for the automatic detection of microcalcifications. An overview of the Microcalcification Detection System is presented, which applies image differencing techniques, feature selection methods, and neural networks for locating microcalcification clusters in mammograms. The Power Spectrum Analysis feature set had the best overall performance with an 83% Probability of Detection and an …

Three Dimensional Localization Of Lesions From Digitized Mammograms, Amy L. Magnus

Theses and Dissertations

This thesis describes new algorithms to localize regions-of-interests (ROIs) three dimensionally from a pair of digitized mammograms. This work is intended to add a layer of sophistication to computer aided diagnosis by putting to use the fixed and measurable parameters of mammographic imaging. The fixed parameters are the source to film orientation and the podium-image distance. Measurable parameters are the rotation angle of the x-ray tube from the horizontal and the compression depth (the distance from compression paddle to contact podium distance) at the time of imaging. As an additional benefit, three dimensional localization algorithms alleviate the confusion radiologists may …

Fatigue Behavior Of The Equine Third Metacarpus: Mechanical Property Analysis, V.A. Gibson, S.M. Stover, R.B. Martin, J.C. Gibeling, N. H. Willits, M.B. Gustafson, L.V. Griffin

Biomedical Engineering

This is the first in a series of experiments to study the fatigue properties of equine cannon (third metacarpal) bone specimens from Throughbred racehorses. Monotonic and fatigue tests to failure were performed in four-point bending on diaphyseal specimens in a 37°C saline bath to answer three initial questions. (a) Will a linear variable differential transducer yield the same elastic modulus as strain gauges? (b) Will fatigue results depend on whether the periosteal or endosteal side of the beam is in tension? (c) Are there regional variations in the monotonic and fatigue properties of the cannon bone midshaft? Eighteen left-right pairs …

Process For Converting Serial Image To The Sterolithography Apparatus (Sla) Slice File With Automatic Base And Support Generation, Charles F. Knapp, P. L. Charles Fischer, Samuel V. Duplessis

Biomedical Engineering Faculty Patents

Method and apparatus for converting a series of serial section images of an object into a three-dimensional model. The method includes acquiring and storing the series of serial section images, converting, zooming, and interpolating serial section images. The method further includes discriminating the series of serial section images to form a binary image, which is then compressed, and filtered. Further, support data for floating or cantilevered portions of the object and base data are generated, the filtered binary image is translated to produce a plurality of vectors representing pixels of the object, and a three-dimensional model of the object is …

In Vitro Activity Of Levofloxacin, Singly And In Combination With Rifamycin Analogs, Against Mycobacterium Leprae, Arvind Madhav Dhople, Maria Antonia Ibáñez

Biomedical Engineering and Sciences Faculty Publications

The in vitro susceptibility of Mycobacterium leprae to levofloxacin was studied by using two biochemical parameters to measure the metabolic activity of the organism. Levofloxacin consistently exhibited twofold greater bactericidal activity than ofloxacin, with the MIC being 0.75 μg/ml. When combined with one of the three rifamycin analogs, synergism was obtained with KRM-1648 and rifabutin but not with rifampin.

Corrosion And Protection Of A Conductive Silver Paste, V. Brusic, G. S. Frankel, J. Roldan, Ravi F. Saraf

Ravi Saraf Publications

One of the possible uses for a conductive paste is as an adhesive in interconnect technology that could replace PbSn solder. The interconnections are expected to perform under a variety of environmental conditions, and with an applied voltage. Thus knowledge of their corrosion and dissolution resistance is of utmost importance. This is a study of the dissolution and protection of polymer/metal composite films, prepared with a high loading of silver or gold particles. Electrochemical tests were conducted in a droplet of triple-distilled water with or without benzotriazole (BTA) and BTA derivatives. Results indicate that, in spite of some protection obtained …

Nanosubharmonics: The Dynamics Of Small Nonlinear Contacts, Nancy Burnham, A Kulik, G Gremaud, Gad Briggs

Nancy A. Burnham

We observed the generation of subharmonics and chaos in a nanometer-sized mechanical contact. To first order, the behavior matches that of macroscopic systems, with some intriguing secondary differences. As the occurrence of periodic behavior (subharmonics) is related to the coefficient of restitution, it may be possible to image local energy dissipation with nanometer resolution.

Effect Of Fiber-Matrix Coupling On The Mechanical Properties Of A Totally Bioabsorbable Composite, Barbaro Jesus Perez

Theses

The mechanical properties of a new class of bioabsorbable polymer-composite based on the amino acid tyrosine and calcium phosphate fibers were studied. The effect of the fiber aspect ratio on the elastic modulus of a discontinuous fiber composite was analyzed using the SMC composite micromechanics computer model. The mechanical stiffness of this polymer was found to be superior to that of poly-p-dioxanone, caprolactone and poly-o-ester.

The fiber surface was modified with methane plasma spray to improve the fiber-matrix coupling. The treated fiber composites had 16-40% higher tensile modulus than the untreated fiber composites. From the flexural test results it is …

Application Of Signal Processing Techniques For Measurement Of Muscle Fiber Conduction Velocity, Satheesh Kumar Swaminathan

Theses

The objectives of this study were to evaluate if muscle fiber conduction velocity (MFCV) could be used as a reliable indicator of fatigue and to characterize the recovery of MFCV after a fatiguing contraction. The decline of MFCV with fatigue was modelled using linear regression and compared with the decline in median frequency (MF). It was found that the percent decline in MF with fatigue was greater than that of MFCV with fatigue and that the decline of MFCV was consistent in all subjects tested. It was thus determined that MFCV could be used as a reliable indicator of fatigue. …

The Morphology Of Uhmwpe Wear Debris Generated By A Hip Joint Simulator, Aaron P. Essner

Theses

The size, quantity and shape of total hip replacement wear debris may identify wear mechanisms as well as play a role in osteolysis. Characterization of wear particles generated from a hip joint simulator was conducted followed by comparison with literature reported in vivo results. The effect of counterface material and lubricant type on particle morphology was assessed. Biomaterial pairs including UHMWPE articulated against CoCr, Alumina and Zirconia were considered. Deionized (D.I.) water and bovine serum were used as lubricants. Particles generated from Alumina/UHMWPE in serum were slightly larger than those for CoCr and Zirconia against UHMWPE in serum. Particle shape …

Lake Evaporation: A Model Study, Jumah Amayreh

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Reliable evaporation data are an essential requirement in any water and/or energy budget studies. This includes operation and management of both urban and agricultural water resources. Evaporation from large, open water surfaces such as lakes and reservoirs may influence many agricultural and irrigation decisions. In this study evaporation from Bear Lake in the states of Idaho and Utah was measured using advanced research instruments (Bowen Ratio and Eddy Correlation). Actual over-lake evaporation and weather data measurements were used to understand the mechanism of evaporation in the lake, determine lake-related parameters (such as roughness lengths, heat storage, net radiation, etc.), and …

Myasthenia Gravis-Like Syndrome Induced By Expression Of Interferon Gamma In The Neuromuscular Junction., Danling Gu, Lise Wogensen, Nigel A. Calcutt, Chunyao Xia, Simin Zhu, John P. Merlie, Howard S. Fox, Jon Lindstrom, Henry C. Powell, Nora Sarvetnick

Journal Articles: Regenerative Medicine

Abnormal humoral responses toward motor end plate constituents in muscle induce myasthenia gravis (MG). To study the etiology of this disease, and whether it could be induced by host defense molecules, we examined the consequences of interferon (IFN) gamma production within the neuromuscular junction of transgenic mice. The transgenic mice exhibited gradually increasing muscular weakness, flaccid paralysis, and functional disruption of the neuromuscular junction that was reversed after administration of an inhibitor of acetylcholinesterase, features which are strikingly similar to human MG. Furthermore, histological examination revealed infiltration of mononuclear cells and autoantibody deposition at motor end plates. Immunoprecipitation analysis indicated …

Sensitization To Self (Virus) Antigen By In Situ Expression Of Murine Interferon-Gamma., Myung-Shik Lee, Matthias Von Herrath, Hans Reiser, Michael B.A. Oldstone, Nora Sarvetnick

Journal Articles: Regenerative Medicine

Autoimmune disease results from inflammatory destruction of tissues by aberrant self-reactive lymphocytes. We studied the autoimmune potential of T lymphocytes immunologically ignorant of viral antigens acting as self antigens and whether the host defense molecule IFN-gamma could stimulate these cells to cytotoxic competency. For this purpose, we produced double transgenic mice expressing pancreatic IFN-gamma as well as lymphocytic choriomeningitis virus (LCMV) nucleoprotein (NP) or glycoprotein (GP) antigen. 100% of the NP+/IFN-gamma+ mice became diabetic before 2 mo of age, while none of the NP single transgenic littermates and only 10% of IFN-gamma single transgenic littermates did. Strikingly, NP+/IFN-gamma+ mice spontaneously …

Laborconsult : An Expert System For Evaluating Fetal Heart Rate And The Progress Of Labor, Wendy Raymond-Fink

Theses

LaborConsult is a rule-based expert system designed to aid the non-expert practitioner in monitoring the progress and fetal tolerance of labor. The expert system obtains from the user the values of the following labor variables: cervical dilatation, fetal station, and the time between and duration of uterine contractions. The rates of cervical dilatation and fetal descent are then calculated and compared to labor standards. Additionally, the consultation assists the user in the analysis of electronic fetal monitor tracings.

The expert system development tool VP-Expert allows the interfacing of the consultation with the spreadsheet Lotus 1-2-3. This enables the creation of …

Development Of A Multi-Lead Trans-Thoracic Impedance Pneumograph For Heart Rate Variability Studies, Curtis Bashford

Theses

In this study, a device that measures respiratory tidal volume and ECG for use in heart rate variability studies, was designed, built and tested. The device developed is a Multi-Lead Trans-Thoracic Impedance Pneumograph, which determines tidal volume on a breath by breath basis, utilizing both hardware and software. It uses standard ECG electrodes which provide increased comfort and inability to the subject over traditional spirometry methods. The device operates similar to traditional bipolar impedance pneumographs except that instead of only one lead (electrode pair), four leads are acquired simultaneously using time-division multiplexing; providing data from different locations and vectors on …

Model Parameter Identification For Rod And Cone Oscillatory Potentials, Kehur Banker

Theses

The use of signal modeling of the oscillatory potential (OP) of the electroretinogram (ERG), in the study of cone-rod interaction is investigated. ERG response data were analyzed for red, orange, blue and white flashes on no background and with red flashes on a blue background (to suppress rod responses). The OP signals were extracted from the ERG by digital bandpass filtering and a signal model was fitted through a simplex algorithm to produce the parameters including "OP envelope-amplitude", latency in terms of "center-time" of the OP-envelope and OP frequency. Amplitude for red flashes with or without a blue background showed …

Wear Of Polyethylene And Hylamer On Cobalt-Chromium : A Knee Simulator Study, Alessandro F. Canonaco

Theses

Two tests were conducted to examine the wear characteristics of tibial bearings used in total knee replacement systems. Each test consisted of six A/P Glide Tibial Bearings each having a conical control arm. The plastic portion of the conical bearings were all made of UHMWPe. Each of these bearing systems was mounted onto a Co-Cr alloy tibial platform and Co-Cr alloy LCS (low contact stress) femoral component . These test samples were mounted onto the New Jersey Mark III Knee Simulator System. The simulator was configured to produce flexion and axial rotation to simulates normal gait. Each test ran at …

Area And Perimeter Measurements Of Cells With Bound Fluorescent Antibodies, Aicha Weiss

Theses

The objective of this research was to geometrically analyze the characteristics of cells, specifically area and perimeter. The images were transferred from HP A900 system to an AVS work station. The images were visualized and manipulated by the AVS which permits the distinction between the cell body, fluorescent object, and background. The intrinsic geometry of the cell was determined by using image processing algorithms written in C. The images were then passed through a threshold filter, thereby yielding a black background and a white cell body. The perimeter calculation was then applied to the black and white images. Two test …

Preoperative Risk Assessment For Cardiac Surgery Using Piecewise Linear Regression Model, Arifa Zafar

Theses

In the present climate of quality assurance policies, rigorous requirements for informed consent, and a constantly changing patient population, a system of preoperative risk assignment for cardiovascular surgery was developed to monitor and evaluate surgical outcomes. The goal of this work is to estimate the preoperative risk associated with cardiac bypass surgery for patients in different risk categories. These risk categories are determined by the Parsonnet model which is based upon studying the severity of illness. The Parsonnet model assigns a risk value to a range of risk factors consisting of patient attributes and disease parameters. The aggregate of these …

Time Domain And Frequency Domain Analysis Of Myoelectric Signals During Muscle Fatigue, Rakesh M. Maniar

Theses

Spectral analysis of the EMG signal is a useful tool for studying the complex phenomena of fatigue. The spectral parameters of mean frequency and median frequency, and the time domain parameter of root mean square have been used to measure localized fatigue.

The normal values of median frequency and its decline with fatigue have not as yet been determined in healthy subjects. This should be done in order to apply spectral analysis for clinical evaluations of abnormal populations. Normal median frequency values and its slope were established in this work for the upper extremity muscles of biceps, triceps and deltoid …

Wear And Friction Of Hylamer And Polyethylene Against Cobalt Chromium A Pin-On-Disc Study, Jerry D'Alessio, Ii

Theses

Understanding friction and wear of biomaterials is essential to the success of any prosthetic joint. A pin-on-disc wear tester is used to find the friction and wear of pins of one material on a coupon of medical grade cobalt chrome. In this experiment six pins of UHMWPe (ultra high molecular weight polyethylene) and six pins of Hylamer® from Du Pont Manufacturing were tested. Four separate runs were made. The tests were performed for ten million cycles, stopping every one to one and a half million cycles for data acquisition. Volumetric wear, wear rate, and coefficients of friction were measured. Both …

Measurement Of The Reaction To Stress And Meditation Using Brain Wave Coherence And Heart Rate Variability, Christopher B. King

Theses

Measurement of physiological parameters associated with the stress response and the relaxation response caused by various forms of meditation can provide valuable information about the reaction of the body to the mind and to the external environment.

This study used two different techniques to evaluate physiological parameters. The first part examined the meditation response by recording the EEG and calculating the coherence between brain waves originating from different parts of the brain. It was found that high levels of coherence in the alpha portion of the EEG frequency band coincided with a restful state associated with the relaxation response. In …

A Pharmacokinetic Model Of The Liver, Samirbhai Rameshbhai Patel

Theses

The liver is the major organ where chemical breakdown of organic and inorganic compounds takes place. A pharmacokinetic heterogeneous model was developed for the local anesthetic and antiarrhythmic drug lidocaine. It was assumed that transport and elimination of lidocaine and its metabolites are linear with concentration. Simulations were done using VisSim software on a 486 based personal computer to obtain concentration profiles for hepatic clearance and for step input of the drug and its metabolites. It was found that the rate of uptake and rate of breakdown were 0.48 min^-1 and 0.49 min^-1 respectively for lidocaine. The results …

Creep Fatigue, Part Iii: Diercks Equation: Modification And Applicability, Tarun Goswami

Biomedical, Industrial & Human Factors Engineering Faculty Publications

Creep-fatigue data of low allow steels were compiled from international sources, and trends in creep-fatigue behavior were identified in Paper I. Methods of life prediction and their trends were examined in Paper II with respect to compiled data. Diercks equation, a multivariate creep-fatigue life extrapolation equation, for SS, 304, in terms of strain range, temperature, hold time and strain rate parameters is modified and extended to the life prediction of low alloy steels in this paper.

Applicability Of Modified Diercks Equation With Nrim Data, Tarun Goswami

Biomedical, Industrial & Human Factors Engineering Faculty Publications

The applicability of the modified Diercks equation (MDE) was assessed with elevated temperature low cycle fatigue (ETLCF) data generated by the National Research Institute for Metals (NRIM) for lCr-Mo-V, 1.25Cr-Mo, 2.25Cr-Mo and 9Cr-lMo steels respectively. The modified Diercks equation was assessed with data generated with symmetrical, slow-fast and hold-time waveforms for low alloy steels. The following characteristics were observed: Symmetrical waveforms: Five strain rates were used with these waveforms where predicted life was by a factor of ± x2 for 77%, 87%, 82% and 92% of data points for lCr-Mo-V, 1.25Cr-Mo, 2.25Cr-Mo and 9CrlMo steels respectively. Slow-fast waveforms: Diercks equation …

Scanning Electron Microscopy Studies Of Ceramic Layers And Interfacial Regions For Calcium Phosphate-Coated Titanium Dental Implants, W. A. Brantley, E. Tufecki, J. C. Mitchell, D. W. Foreman, E. A. Mcglumphy

Cells and Materials

The surface and cross-section characteristics of the plasma-sprayed calcium phosphate coatings, along with the microstructures and elemental compositions near the titanium alloy interface, were investigated by scanning electron microscopy for two different dental implants of proprietary compositions: Integra!® (Calcitek) and BioVent ® (Dentsply). Elemental concentrations (Ca, P, Ti, AI, and V) near the interfaces were obtained by X-ray energy-dispersive spectroscopy. Coating surfaces exhibited a splat deposition topography of greatly differing microstructural scale for the two implants, along with other features characteristic of the plasma-spraying process; cross-sections of the coatings revealed minimal porosity. Some interdiffusion of principally titanium and calcium was …

In Vitro Characterization Of Transforming Growth Factor-Ss1-Loaded Composites Of Biodegradable Polymer And Mesenchymal Cells, S. B. Nicoll, A. E. Denker, R. S. Tuan

Cells and Materials

A porous, biodegradable polymer composite was fabricated from poly(L-lactic acid) (PLLA) using a solvent- casting particulate-leaching technique, and loaded with recombinant human transforming growth factor ß-1 (TGF-ß1). Tissue culture polystyrene (TCPS) and PLLA disks loaded with bovine serum albumin (BSA) served as controls. Polymer specimens were seeded at high cell density with C3H10T1/2 cells, a mouse embryonic cell line capable of differentiating into various connective tissue cell types. The polymer matrices degraded slowly in physiological saline over four weeks, with a sustained yet sporadic release of active TGF-ß1; a more controlled release of TGF-ß1 was observed in serum-containing culture medium …