Engineering Commons^™

Development Of An Atrophic Nonunion Model And Comparison To A Closed Healing Fracture In Rat Femur, Takeshi Kokubu, David J. Hak, Scott J. Hazelwood, A. Hari Reddi

Biomedical Engineering

Although most fractures heal, some fail to heal and become nonunions. Many animal models have been developed to study problems of fracture healing. The majority of nonunion models have involved segmental bone defects, but this may not adequately represent the biologic condition in which nonunions clinically develop. The objective of the present study is to develop a nonunion model that better simulates the clinical situation in which there is soft tissue damage including periosteal disruption and to compare this model to a standard closed fracture model utilizing identical fracture stabilization, providing a similar mechanical environment. A total of 96 three …

Reactive Oxygen Species Modulate Coronary Wall Shear Stress And Endothelial Function During Hyperglycemia, Eric R. Gross, John F. Ladisa, Dorothee Weihrauch, Lars E. Olson, Tobias T. Kress, Douglas Anthony Hettrick, Paul S. Pagel, David C. Warltier, Judy R. Kersten

Biomedical Engineering Faculty Research and Publications

Hyperglycemia is associated with generation of reactive oxygen species (ROS), and this action may contribute to accelerated atherogenesis. We tested the hypothesis that hyperglycemia produces alterations in left anterior descending coronary artery (LAD) wall shear stress concomitant with endothelial dysfunction and ROS production in dogs (n = 12) instrumented for measurement of LAD blood flow, velocity, and diameter. Dogs were randomly assigned to receive vehicle (0.9% saline) or the superoxide dismutase mimetic 4- hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (tempol) and were administered intravenous infusions of d-glucose to achieve target blood glucose concentrations of 350 and 600 mg/dl (moderate and severe hyperglycemia, respectively). Endothelial …

Short-Term Water Use Dynamics In Drainage Lysimeters, Musa V. Dlamini

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Turfgrass water use (seasonal turfET) and crop coefficients were determined and a mathematical soil-water balance model for non-weighing drainage lysimetcrs, which simulates the occurrence (timing and amount) of drainage, was developed. Pairs of non-weighing drainage lysimeters were used to determine crop coefficients for turfgrass in four locations in the state of Utah: Logan Golf and Country Club, Murray Golf Course, Brigham Young University (Spanish Fork) Experiment Farm, and Sunbrook Golf Course (St. George).

Daily weather data including air temperature, relative humidity, average wind travel, total solar radiation, precipitation, and average soil temperature were collected with an electronic weather station at …

Effects Of Diabetes And Aging On Posture And Acceleration Thresholds During Lateral Translations, Samantha Jean Richerson

Doctoral Dissertations

Research objectives. One source of falls in the elderly may be an inability to sufficiently adjust to transient postural perturbations or slips. Identifying useful predictors of fall potential, as well as factors that affect the ability of an individual to detect a movement of the standing support surface may provide insight into postural stability and methods to increase stability in elders. To do this, acceleration thresholds to short, precise, lateral platform translations and the resultant psychophysical responses of adults with early Type 2 diabetes to age-matched controls and young adults were measured.

Methods. Using an innovative SLIP-FALLS platform, …

Investigation Into The Ultrasound Setting Of Glass Ionomer Cements. Part I. Postulated Modalities, Mark R. Towler, C. M. Crowley, R. G. Hill

Chemical and Biochemical Engineering Faculty Research & Creative Works

Fuji IX glass is a low phosphate, low soda containing glass which has strontia incorporated as a radio-pacifier. This glass material was analyzed during exposure to different durations of ultrasound in an attempt to determine how the glass phase reacts. Cross sections of Fuji IX cement, set both conventionally and by ultrasound, were subsequently compared by microscopy. The resultant data were analyzed in detail.

Adenosine Type 1 (A ) Receptors Mediate Protection Against Myocardial 1 Infarction Produced By Chronic, Intermittent Ingestion Of Ethanol In Dogs, Franz Kehl, John G. Krolikowski, John F. Ladisa, Judy R. Kersten, David C. Warltier, Paul S. Pagel

Biomedical Engineering Faculty Research and Publications

Background: Chronic consumption of small amounts of ethanol protects myocardium from ischemic injury. We tested the hypothesis that adenosine type 1 (A₁) receptors mediate these beneficial effects.

Methods: Dogs (n=37) were fed with ethanol (1.5 g/kg) or water mixed with dry food twice per day for 12 weeks, fasted overnight before experimentation, and instrumented for measurement of hemodynamics. Dogs received intravenous drug vehicle (50% polyethylene glycol in 0.1 N sodium hydroxide and 0.9% saline over 15 min) or the selective A₁ receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, 0.8 mg/kg over 15 min) and were subjected …

Strategies For Improving Neural Signal Detection Using A Neural-Electronic Interface, Robert B. Szlavik

Biomedical Engineering

There have been various theoretical and experimental studies presented in the literature that focus on interfacing neurons with discrete electronic devices, such as transistors. From both a theoretical and experimental perspective, these studies have emphasized the variability in the characteristics of the detected action potential from the nerve cell. The demonstrated lack of reproducible fidelity of the nerve cell action potential at the device junction would make it impractical to implement these devices in any neural prosthetic application where reliable detection of the action potential was a prerequisite. In this study, the effects of several different physical parameters on the …

Nonlinear Elastic Material Property Estimation Of Lower Extremity Residual Limb Tissues, Ergin TöNüK, M. Barbara Silver-Thorn

Biomedical Engineering Faculty Research and Publications

The interface stresses between the residual limb and prosthetic socket have been studied to investigate prosthetic fit. Finite-element models of the residual limb-prosthetic socket interface facilitate investigation of the mechanical interface and may serve as a potential tool for future prosthetic socket design. However, the success of such residual limb models to date has been limited, in large part due to inadequate material formulations used to approximate the mechanical behavior of residual limb soft tissues. Nonlinear finite-element analysis was used to simulate force-displacement data obtained during in vivo rate-controlled (1, 5, and 10 mm/s) cyclic indentation of the residual limb …

Measuring The Effect Of Airway Pressure On Pulmonary Arterial Diameter In The Intact Rat Lung, Robert C. Molthen, Steven Thomas Haworth, Amy Heinrich, Christopher A. Dawson

Biomedical Engineering Faculty Research and Publications

To study the relationship between transpulomnary [sic] pressure (Ptp), intravascular pressure (Pv), and the pulmonary arterial tree structure, morphometric measurements of pulmonary arterial trees were made in intact lungs from Sprague-Dawley rats. Using cone beam micro-CT and techniques we developed for imaging small animal lungs, volumetric CT data were acquired for Ptp from 0 - 12 mmHg and Pv from 5 - 30 mmHg. The diameter, D (measured range approximately 0.08-2.0 mm), vs. pressure, P, relation can be described by D(P) = D(0)(1+ α P), where α is a distensibility coefficient. Unlike studies performed in larger animals, where changes in …

Spect Imaging Of Pulmonary Blood Flow In A Rat, Christian Wieholt, Robert C. Molthen, Roger H. Johnson, Christopher A. Dawson, Anne V. Clough

Biomedical Engineering Faculty Research and Publications

Small animal imaging is experiencing rapid development due to its importance in providing high-throughput phenotypic data for functional genomics studies. We have developed a single photon emission computed tomography (SPECT) system to image the pulmonary perfusion distribution in the rat. A standard gamma camera, equipped with a pinhole collimator, was used to acquire SPECT projection images at 40 sec/view of the rat thorax following injection of Tc99m labeled albumin that accumulated in the rat's lungs. A voxel-driven, ordered-subset expectation maximization reconstruction was implemented. Following SPECT imaging, the rat was imaged using micro-CT with Feldkamp conebeam reconstruction. The two reconstructed image …

Orientation Of Self-Assembled Block Copolymer Cylinders Perpendicular To Electric Field In Mesoscale Film, S. Elhadj, J. W. Woody, V. S. Niu, Ravi F. Saraf

Ravi Saraf Publications

The possibility of using self-assembled films of block polymers as templates to fabricate nanoscale structures for devices has attracted great attention towards this class of material. Self-assembly of a block copolymer can be directed by using an electric field to orient features (i.e., ~10-nm-diam cylinders) parallel to the electric field, making the material more attractive as a nanoscale lithography mask. In this letter we describe an approach to influence the electric field orientation phenomena by interfacial effects. As a result, the 15-nm-diam polystyrene cylinders of the polystyrene–polyisoprene–polystyrene triblock copolymer orient perpendicular to the electric field. The described approach along with …

Fuzzy Modeling Of Skin Permeability Coefficients, Angela K. Pannier, Rhonda M. Brand, David D. Jones

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Purpose. The purpose of this work was to determine whether a new modeling methodology using fuzzy logic can predict skin permeability coefficients that are given compound descriptors that have been proven to affect percutaneous penetration.
Methods. Three fuzzy inference models were developed using subtractive clustering to define natural structures within the data and assign subsequent rules. The numeric parameters describing the rules were refined through the use of an Adaptive Neural Fuzzy Inference System implemented in MatLab. Each model was evaluated using the entire data set. Then predicted outputs were compared to the published experimental data.
Results. All databases produced …

The Development Of A Biodegradable Scaffold For A Tissue Engineered Heart Valve, Thomas Adam Alheidt

Theses

In the current state of medical technology, there exists the need for a quality medical device to replace a failing heart valve. Presently, mechanical valves as well as donor tissue valves, either from humans or animals are used to replace failing heart valves. These valves although they can operate in the heart satisfactorily are not equal to the body replacing its own valve. Tissue Engineering in simple terms is the field of helping the body replace its own failing organ. In scientific terms, Tissue Engineering is a relatively young field, a majority of the major advancements have come in the …

Evaluation Of Intra-And Inter-Fraction Motion In Breast Radiotherapy Using Electronic Portal Imaging Cine Loops, Chrison Lee, Edward Yu, Tomas Kron

Oncology Presentations

Parallel tangent breast irradiation is commonly used postbreast conservation surgery for early breast cancer patient without lymph node involvement to improve local disease control. Intra-fractional and inter-fractional variabilities are often presented in daily treatment setup. The present pilot study used Electronic Portal Imaging (EPI) to evaluate intra-and inter-fraction motion in patients undergoing simple breast tangent radiotherapy.

Clinical Blood Flow Quantification With Segmented K-Space Magnetic Resonance Phase Velocity Mapping, George P. Chatzimavroudis, Haosen Zhang, Sandra S. Halliburton, James R. Moore, Orlando Simonetti, Paulo R. Schvartzman, Arthur E. Stillman, Richard D. White

Chemical & Biomedical Engineering Faculty Publications

To evaluate the accuracy of segmented k-space magnetic resonance phase velocity mapping (PVM) in quantifying aortic blood flow from through-plane velocity measurements.

Two segmented PVM schemes were evaluated, one with seven lines per segment (seg-7) and one with nine lines per segment (seg-9), in twenty patients with cardiovascular disease. A non-segmented (non-seg) PVM acquisition was also performed to provide the reference data.

There was agreement between the aortic flow curves acquired with segmented and non-segmented PVM. The calculated systolic and total flow volume per cycle from the seg-7 and the seg-9 scans correlated and agreed with the flow volumes from …

The Economic Impacts Of Various Public-Policy Scenarios For Methane Recovery On Dairy Farms, Richard Stowell, Chris G. Henry

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

The feasibility of anaerobic digesters for dairy and swine operations in Nebraska was evaluated using EPA’s Ag Star software program Farmworks 2.0 (1997) and local values for farm energy costs, mainly electricity. Four incentive programs were considered that would subsidize anaerobic digestion. Installation of a digester system is a significant investment that is currently very difficult to justify economically to Nebraska producers based upon consideration of readily quantifiable income and expenses, regardless of farm size. Larger dairy operations looking to invest in this technology would benefit most from a tax credit and/or subsidized electricity sales, policies that relate directly to …

Simplified Meta-Analysis Of Clinical Trials In Resuscitation, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Objective: To present and demonstrate a new simplified method for synthesizing results of multiple clinical trials in resuscitation research. Methods: The mean difference across studies in the proportion of favorable outcomes between experimental and control groups is calculated. This difference is shown to have a t-distribution. Its significance can be ascertained with a simple t-test. The analysis can be implemented in a one-page computer spreadsheet. Results: Simplified meta-analysis provides high sensitivity and can be extended to include weighting of studies according to size or quality, comparison of subgroups of studies, tests for outliers, and calculation of the power of the …

Interposed Abdominal Compression Cpr: A Comprehensive Evidence Based Review, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Interposed abdominal compression (IAC)-CPR includes all steps of standard external CPR with the addition of manual mid-abdominal compressions in counterpoint to the rhythm of chest compressions. IAC-CPR can increase blood flow during CPR about two fold compared to standard CPR without IAC, as shown by 6 of 6 studies in computer models and 19 of 20 studies in various animal models. The addition of IAC has clinical benefit in humans, as indicated in 10 of 12 small to medium sized clinical studies. The technique increases the frequency of immediate return of spontaneous circulation for in-hospital resuscitations from roughly 25% to …

Feasibility Of Radiographic Absorptiometry Of The Mandible As An Osteoporosis Screening Method, Julie A. Skipper

Browse all Theses and Dissertations

The purpose of this work was to develop and evaluate single- and dual-energy radiographic absorptiometry (RA) for the measurement of mandibular bone mineral density (BMD), using standard dental equipment, that would allow for inexpensive and widespread osteoporosis screening. Accurately measured x-ray tube spectra are important for validating the simulations used in the design of the method. A constrained least-squares deconvolution technique for reducing the detector-induced blurring of the energy spectrum was developed. Application of this analytic correction to spectra acquired with a NaI-photomultiplier detector improved the measured data by 20-60%. Implementation of the screening method is accomplished by simultaneously acquiring …

Interaction Of Disparity And Accommodative Vergence, Michele Liu Kung

Theses

To fixate on a target that moves from far to near, changes in blur and disparity activate accommodation and disparity vergence. The goal of this study was to experimentally obtain eye movement data from four subjects, and analyze this data using through a new signal processing algorithm known as independent component analysis (ICA). Preliminary data suggest that three underlying neural subcomponents are present where the two components of disparity vergence initiate the movement and the accommodative portion is activated to facilitate the steady state portion of the response.

ICA was used as a blind source separation technique to analyze experimental …

Application And Performance Of Constructed Wetlands For Runoff From Small Open Lots, C. G. Henry, J. P. Harner Iii, T. D. Strahm, M. A. Reynolds

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

Vegetative systems have long been studied and evaluated as alternatives to conventional storage, treatment, and land application systems. This paper discusses the application of vegetative systems, primarily constructed wetlands, as a runoff treatment technology for small livestock operations. The approach used for two small dairies and one beef cattle feedlot is discussed. Cost data for these operations is included as well as nutrient reduction performance results from a three year sampling period for the KS Dairy.

Molecular Dynamics Of Soy-Protein Isolate Films Plasticized By Water And Glycerol, S.-G. Choi, K. M. Kim, Milford Hanna, Curtis L. Weller, W. L. Kerr

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The effects of water and glycerol on the molecular mobility of a soy-protein isolate (SPI)-based film were investigated using ¹H nuclear magnetic resonance (NMR). SPI-films were prepared with different glycerol contents and equilibrated to various levels of water activity (a_w). The distributed transverse relaxation of film samples showed 2 distinct components: a solid-like fraction (T_2s*) and a liquid-like fraction (T_2m*). The peak T_2s* values of films with lower glycerol concentration were more sensitive to variation in aw. As a_w increased, the change of solid-like to liquid-like fraction was observed in …

Influence Of Sorghum Wax, Glycerin, And Sorbitol On Physical Properties Of Soy Protein Isolate Films, Ki Myong Kim, David B. Marx, Curtis Weller, Milford Hanna

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Sorghum wax, sorbitol, glycerin, and soy protein isolate (SPI) composite films were prepared. Effects of sorghum wax, sorbitol, and glycerin concentrations on various films were evaluated using response surface methodology. All independent variables significantly (P < 0.05) affected film water vapor permeability (WVP), tensile strength (TS), elongation at break (E), total color difference, and total soluble matter (TSM). Increasing the sorghum wax concentration decreased WVP and E. As sorbitol content increased in the composite films, WVP and TS increased. Sorbitol had a critical point of 2–5 g/5 g SPI for low values of TSM. The addition of sorbitol contributed more to the properties of the film than did glycerin.

Compact Supercell Method Based On Opposite Parity For Bragg Fibers, Wang Zhi, Ren Guobin, Lou Shuquin, Liang Weijun, Shangping Guo

Electrical & Computer Engineering Faculty Publications

The supercell- based orthonormal basis method is proposed to investigate the modal properties of the Bragg fibers. A square lattice is constructed by the whole Bragg fiber which is considered a supercell, and the periodical dielectric structure of the square lattice is decomposed using periodic functions (cosine). The modal electric field is expanded as the sum of the orthonormal set of Hermite-Gaussian basis functions based on the opposite parity of the transverse electric field. The propagation characteristics of Bragg fibers can be obtained after recasting the wave equation into an eigenvalue system. This method is implemented with very high efficiency …

Plasma Interaction With Microbes, M. Laroussi, D. A. Mendis, M. Rosenberg

Electrical & Computer Engineering Faculty Publications

The germicidal effects of a non-equilibrium atmospheric pressure plasma generated by a novel resistive barrier discharge on representatives of the two classes of bacteria (Gram-negative and Gram-positive) are discussed. The plasma exposure, while being lethal to both bacterial classes, also produced gross structural damage in the Gram-negative E. coli while none was observed in the more structurally robust Gram-positive Bacillus subtilis. An electrophysical process involving the role of the electrostatic tension on a charged body in a plasma is invoked to explain both observations. Since the efficacy of this electrophysical process depends not only on the tensile strength of …

Mechanisms Of Volatile Anesthetic-Induced Myocardial Protection, Lynda M. Ludwig, Judy R. Kersten, Katsuya Tanaka, Weidong Gu, John F. Ladisa, David C. Warltier, Paul S. Pagel

Biomedical Engineering Faculty Research and Publications

Volatile anesthetics protect myocardium against reversible and irreversible ischemic injury. Experimental evidence from several in vitro and in vivo animal models demonstrates that volatile agents enhance the recovery of stunned myocardium and reduce the size of myocardial infarction after brief or prolonged coronary artery occlusion and reperfusion, respectively. This protective effect persists after the anesthetic has been discontinued, a phenomenon known as anesthetic-induced preconditioning (APC). Recent clinical data also demonstrates evidence of APC in patients during cardiac surgery. Thus, administration of volatile anesthetics may represent a novel therapeutic approach that reduces morbidity and mortality associated with perioperative myocardial ischemia and …

Three-Dimensional Reconstruction Algorithm For A Reverse-Geometry Volumetric Ct System With A Large-Array Scanned Source, Taly Gilat Schmidt, Rebecca Fahrig, Norbert J. Pelc

Biomedical Engineering Faculty Research and Publications

We have proposed a CT system design to rapidly produce volumetric images with negligible cone beam artifacts. The investigated system uses a large array scanned source with a smaller array of fast detectors. The x-ray source is electronically steered across a 2D target every few milliseconds as the system rotates. The proposed reconstruction algorithm for this system is a modified 3D filtered backprojection method. The data are rebinned into 2D parallel ray projections, most of which are tilted with respect to the axis of rotation. Each projection is filtered with a 2D kernel and backprojected onto the desired image matrix. …

Sensitivity To Hand Path Curvature During Reaching, Kyle P. Lillis, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

People optimize reaching to make straight and smooth movements. We performed experiments characterizing human sensitivity to hand path deviations from a straight reach. Vision of the arm was blocked. Subjects either moved the hand along paths of constrained curvature, or a robot moved the relaxed limb along similar trajectories (active and passive conditions, respectively). Subjects responded after each trial whether or not they thought the movement curved convex right. In a series of three experiments, we tested the effects of modifying visual feedback of hand position to suppress curvature, isotonic muscle activation, and a distracter task on subjects ability to …

Ccr4-Bearing T Cells Participate In Autoimmune Diabetes., Soon H. Kim, Mary M. Cleary, Howard S. Fox, Icos Coporation, Nora Sarvetnick

Journal Articles: Regenerative Medicine

Chemokine receptor expression is exquisitely regulated on T cell subsets during the course of their migration to inflammatory sites. In the present study we demonstrate that CCR4 expression marks a pathogenic population of autoimmune T cells. CCR4 was found exclusively on memory CD4(+) T cells during the progression of disease in NOD mice. Cells expressing the CCR4 ligand TARC (thymus- and activation-regulated chemokine) were detected within infiltrated islets from prediabetic mice. Interestingly, neutralization of macrophage-derived chemokine (MDC) with Ab caused a significant reduction of CCR4-positive T cells within the pancreatic infiltrates and inhibited the development of insulitis and diabetes. Furthermore, …

Weibull Model Development For Fatigue Crack Growth, Bobby Day, Tarun Goswami

Biomedical, Industrial & Human Factors Engineering Faculty Publications

This effort is an attempt to "Weibullize" fatigue crack growth rate data as a function of stress intensity range (ΔΚ). It is not a classical Weibull application in that it does not address a population but rather treats rate of crack growth as a fraction of the highest rate of crack growth rate in the data set (usually the final data point of the set) as the "failed fraction of a population." All da/dN values are converted to a percentage or fraction of the 100% data value, processed into a linear relationship and plotted against the natural log of the …