Biomedical Engineering and Bioengineering Commons^™

Use Of Photoactivated Crosslinking Agents For Vascular Repair And Local Drug Delivery, Kaia L. Kloster

Light Activated Tissue Regeneration and Therapy

No abstract provided.

Photodynamic Modulation Of Wound Healing And Inhibition Of Tissue Degradation, Michael R Hamblin, Tatiana Demidova, Faten Gad, Touqir Zahra, Tayyaba Hasan

Light Activated Tissue Regeneration and Therapy

No abstract provided.

Direct Least-Squares Ellipse Fitting, Jane Courtney, Annraoi Depaor

Conference Papers

Many biological and astronomical forms can be best represented by ellipses. While some more complex curves might represent the shape more accurately, ellipses have the advantage that they are easily parameterised and define the location, orientation and dimensions of the data more clearly. In this paper, we present a method of direct least-squares ellipse fitting by solving a generalised eigensystem. This is more efficient and more accurate than many alternative approaches to the ellipse-fitting problem such as fuzzy c-shells clustering and Hough transforms. This method was developed for human body modelling as part of a larger project to design a …

Odor, H2S And Nh3 Emissions From Phototrophic And Non-Phototrophic Anaerobic Swine Lagoons, Jason Byler, Dennis D. Schulte, Richard K. Koelsch

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

Odor, ammonia and hydrogen sulfide emission data were collected from three phototrophic and three non-phototrophic anaerobic swine lagoons in eastern Nebraska from May 27th to June 18th (late spring) and from July 7th to August 13th (summer). The greatest odor, hydrogen sulfide and ammonia emission rates were from non-phototrophic lagoons during late spring (24.5 OU m^-2 s^-1, 3.2 μg-H₂S m^-2 s^-1, 34.9 kg NH₃-N ha^-1 d^-1, respectively). Non-phototrophic lagoon odor, ammonia and hydrogen sulfide emission rates were much higher in late spring than summer (24.5 vs. 4.8 …

Cardioprotection By Glucose-Insulin-Potassium: Dependence On KAtp Channel Opening And Blood Glucose Concentration Before Ischemia, John F. Ladisa, John G. Krolikowski, Paul S. Pagel, David C. Warltier, Judy R. Kersten

Biomedical Engineering Faculty Research and Publications

We tested the hypothesis that glucose-insulin-potassium (GIK)-induced protection against myocardial infarction depends on ATP-dependent K⁺ (K_ATP) channel activation and is abolished by hyperglycemia before the ischemia. Dogs were subjected to a 60-min coronary artery occlusion and 3-h reperfusion in the absence or presence of GIK (25% dextrose; 50 IU insulin/l; 80 mM/l KCl infused at 1.5 ml·kg⁻¹·h⁻¹) beginning 75 min before coronary artery occlusion or 5 min before reperfusion. The role of K_ATP channels was evaluated by pretreatment with glyburide (0.1 mg/kg). The efficacy of GIK was investigated with increases in blood …

Investigation Into The Ultrasonic Setting Of Glass Ionomer Cements : Part Ii Setting Times And Compressive Strengths, E. Twomey, Mark R. Towler, C. M. Crowley, J. Doyle, S. Hampshire

Chemical and Biochemical Engineering Faculty Research & Creative Works

The ultrasonic setting of glass ionomer cements (GIC) was discussed. It was observed that the ultrasonic setting resulted in improvements of compressive strength. An increase in the PAA molecular weight from PAA50 to PAA200 resulted in an increase in the strength, but with a further increase in the PAA molecular weight to PAA450, there was a reduction in the strength. Results show that the strength of the ultrasonically set materials after 1 day were close to the values for the 7 days chemically set samples.

Pressure Distribution Around Spherical Distal Ball-Tip In Ultrasound Angioplasty, Graham Gavin, Garrett B. Mcguinness, Finbar Dolan, M.S. J. Hashmi

Conference Papers

INTRODUCTION Ultrasound Angioplasty has been shown to be effective in the removal and re-canalising of blockages in arteries (Siegel RJ, 1993). By delivering therapeutic ultrasound to the blockage, via a wire waveguide to a ball-tip, the lesion or thrombus is affected by pressure waves, micro streaming, cavitation and direct contact with the oscillating ball-tip. Most work to date has concentrated on a spherical ball-tip geometry at the distal end of the wire waveguide (Steffen, 1994 and Rosenschein, 1996). Tip displacements usually lie between 10 - 100m (peak-to peak) and ball tip diameters between 1 - 2mm (Atar, 1999 and Yock, …

A High -Order Finite Difference Method For Solving Bioheat Transfer Equations In Three-Dimensional Triple -Layered Skin Structure, Haofeng Yu

Doctoral Dissertations

Investigations on instantaneous skin burns are useful for an accurate assessment of burn-evaluation and for establishing thermal protections for various purposes. Meanwhile, hyperthermia with radiation is important in the treatment of cancer, and it is essential for developers and users of hyperthermia systems to predict, and interpret correctly the biomass thermal and vascular response to heating. In this dissertation, we employ the well-known Pennes' bioheat transfer equation to predict the degree of skin burn and the temperature distribution in hyperthermia cancer treatment.

A fourth-order compact finite difference scheme is developed to solve Pennes' bioheat transfer equation in a three-dimensional single …

Field Effect Control Of Electrokinetic Transport Phenomena In Nanofluidics, Song Xue

Mechanical & Aerospace Engineering Theses & Dissertations

Naturally nanofluidics has applications demanding the samples to be handled in exceedingly small quantities due to the small size of the fluidic channels in nanofluidic devices, such as characterization of single biomolecules. Fluids confined in channels of nanometer characteristic dimensions exhibit physical behaviors not observed in large conduits. Charge properties of the nanochannel wall in contact with an aqueous solution play essential roles in the involved electrokinetic transport phenomena occurring in nanofluidic devices. In addition to tuning the charge properties of the nanofluidic channel wall by adjusting the solution properties such as pH and background salt concentration, field effect transistor …

A Theoretical Analysis Of Long-Term Bisphosphonate Effects On Trabecular Bone Volume And Microdamage, Jeffry S. Nyman, Oscar C. Yeh, Scott J. Hazelwood, R. Bruce Martin

Biomedical Engineering

Bisphosphonates increase bone mass and reduce fracture risk, but their anti-resorptive action may lead to increases in fatigue microdamage. To investigate how bisphosphonate effects influence changes in bone volume and microdamage in the long term, a strain-adaptive model of bone remodeling and microdamage balance was developed for a continuum-level volume of postmenopausal trabecular bone by invoking Frost's mechanostat hypothesis. Both disuse and fatigue microdamage were assumed to stimulate the activation frequency of basic multicellular units (BMUs) such that bone remodeling served to remove excess bone mass and microdamage. Bisphosphonate effects were simulated as follows: low, intermediate, high, or complete suppression …

Energy-Landscape-Model Analysis For Irreversibility And Its Pulse-Width Dependence In Cells Subjected To A High-Intensity Ultrashort Electric Pulse, R. P. Joshi, Q. Hu, Karl H. Schoenbach, Stephen J. Beebe

Bioelectrics Publications

We provide a simple, but physical analysis for cell irreversibility and apoptosis in response to an ultrashort (nanosecond), high-intensity electric pulse. Our approach is based on an energy landscape model for determining the temporal evolution of the configurational probability function p(q). The primary focus is on obtaining qualitative predictions of a pulse width dependence to apoptotic cell irreversibility that has been observed experimentally. The analysis couples a distributed electrical model for current flow with the Smoluchowski equation to provide self-consistent, time-dependent transmembrane voltages. The model captures the essence of the experimentally observed pulse-width dependence, and provides a possible physical picture …

Impact Of Pulmonary Arterial Endothelial Cells On Duroquinone Redox Status, Marilyn P. Merker, Robert D. Bongard, Gary S. Krenz, Hongtao Zhao, Viola S. Fernandes, Balaraman Kalyanaraman, Neil Hogg, Said H. Audi

Biomedical Engineering Faculty Research and Publications

The study objective was to use pulmonary arterial endothelial cells to examine kinetics and mechanisms contributing to the disposition of the quinone 2,3,5,6-tetramethyl-1,4-benzoquinone (duroquinone, DQ) observed during passage through the pulmonary circulation. The approach was to add DQ, durohydroquinone (DQH₂), or DQ with the cell membrane-impermeant oxidizing agent, ferricyanide (Fe(CN)₆³⁻), to the cell medium, and to measure the medium concentrations of substrates and products over time. Studies were carried out under control conditions and with dicumarol, to inhibit NAD(P)H:quinone oxidoreductase 1 (NQO1), or cyanide, to inhibit mitochondrial electron transport. In control cells, DQH₂ appears …

Effect Of Ventilation Rate On Instilled Surfactant Distribution In The Pulmonary Airways Of Rats, Joseph C. Anderson, Robert C. Molthen, Christopher A. Dawson, Steven Thomas Haworth, Joseph L. Bull, Matthew R. Glucksburg, James B. Grotberg

Biomedical Engineering Faculty Research and Publications

Liquid can be instilled into the pulmonary airways during medical procedures such as surfactant replacement therapy, partial liquid ventilation, and pulmonary drug delivery. For all cases, understanding the dynamics of liquid distribution in the lung will increase the efficacy of treatment. A recently developed imaging technique for the study of real-time liquid transport dynamics in the pulmonary airways was used to investigate the effect of respiratory rate on the distribution of an instilled liquid, surfactant, in a rat lung. Twelve excised rat lungs were suspended vertically, and a single bolus (0.05 ml) of exogenous surfactant (Survanta, Ross Laboratories, Columbus, OH) …

Stent Design Properties And Deployment Ratio Influence Indexes Of Wall Shear Stress: A Three-Dimensional Computational Fluid Dynamics Investigation Within A Normal Artery, John F. Ladisa, Lars E. Olson, Ismail Guler, Douglas Anthony Hettrick, Said H. Audi, Judy R. Kersten, David C. Warltier, Paul S. Pagel

Biomedical Engineering Faculty Research and Publications

Restenosis limits the effectiveness of stents, but the mechanisms responsible for this phenomenon remain incompletely described. Stent geometry and expansion during deployment produce alterations in vascular anatomy that may adversely affect wall shear stress (WSS) and correlate with neointimal hyperplasia. These considerations have been neglected in previous computational fluid dynamics models of stent hemodynamics. Thus we tested the hypothesis that deployment diameter and stent strut properties (e.g., number, width, and thickness) influence indexes of WSS predicted with three-dimensional computational fluid dynamics. Simulations were based on canine coronary artery diameter measurements. Stent-to-artery ratios of 1.1 or 1.2:1 were modeled, and computational …

Brain Motion And Deformation During Closed Head Injury In The Presence Of Cerebrospinal Fluid, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

This paper presents a new analysis of the physics of closed head injury following brief, intense acceleration of the head. It focuses upon the buoyancy of the brain in cerebrospinal fluid, which protects against damage, the propagation of strain waves through the brain substance, which causes damage, and the concentration of strain in critical anatomic regions, which magnifies damage. Numerical methods are used to create animations or "movies" of brain motion and deformation. Initially a 1 cm gap filled with cerebrospinal fluid (CSF) separates the brain from the skull. Whole head acceleration induces artificial gravity within the skull. The brain …

On-The-Go Soil Sensors For Precision Agriculture, Viacheslav I. Adamchuk, J. W. Hummel, M. T. Morgan, S. K. Upadhyaya

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The basic objectives of site-specific management of agricultural inputs are to increase profitability of crop production, improve product quality, and protect the environment. Information about the variability of different soil attributes within a field is essential for the decision-making process. The inability to obtain soil characteristics rapidly and inexpensively remains one of the biggest limitations of precision agriculture. Numerous researchers and manufacturers have attempted to develop on-the-go soil sensors to measure mechanical, physical and chemical soil properties. The sensors have been based on electrical and electromagnetic, optical and radiometric, mechanical, acoustic, pneumatic, and electrochemical measurement concepts. While only electric and …

Simple Feature Identification And Matching For Stereoscopic Imaging, Jane Courtney, Annraoi Depaor

Conference Papers

Many camera calibration techniques used in stereoscopic imaging require corresponding points in image pairs to be identified. The best matches tend to come from very distinctive regions, hence it is preferable to use only these points and reject points from more homogeneous regions. Often points are selected and matched by a combination of user input and automated matching. However, for most techniques, the more matching points identified, the more accurate and robust the calibration. Therefore, it is desirable to alleviate the need for user input and to automate the point selection process. In the feature matching technique described here, a …

Computerized Biofeedback Knee Goniometer: Acceptance And Effect On Exercise Behavior In Post-Total Knee Arthroplasty Rehabilitation, Todd A. Kuiken, Hagay Amir, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Objective

To assess device accuracy, patient acceptance, and effect of a computerized biofeedback knee goniometer (CBG), on patients’ compliance with active range of motion (AROM) exercises after total knee arthroplasty (TKA).

Design

Two-stage study: measurement validation on asymptomatic controls and an unblinded, multiple crossover trial.

Setting

Inpatient rehabilitation.

Participants

Asymptomatic controls (n=14) and post-TKA inpatients (n=11).

Interventions

For measurement validation, CBG-angle measurements were compared with manual, clinician-obtained angles. To assess motivational effect, the CBG was worn after TKA; on alternating days, it either monitored AROM silently (no feedback) or provided audiovisual feedback about reaching preset range of motion (ROM) goals …

Parametric Synthesis Of Sign Language, Jerome Allen

Theses

The isolation of the deaf community from mainstream society is in part due to the lack of knowledge most hearing people have of sign language. To most, there seems to be little need to learn a language that is spoken by such a small minority unless perhaps a relative is unable to hear. Even with a desire to learn, the task may seem insurmountable due to the unique formational and grammatical rules of the language.

This linguistic rift has led to the call for an automatic translation system with the ability to take voice or written text as input and …

Mathematical Modeling And Simulation Of Human Motion Using 3-Dimensional, Multi-Segment Coupled Pendulum System : Derivation Of A Generalized Formula For Equations Of Motion, Loay Ahmed-Wasfe Al-Zube

Theses

The use of mathematical models to investigate the dynamics of human movement relies on two approaches: forward dynamics and inverse dynamics. In this investigation a new modeling approach called the Boundary Method is outlined. This method addresses some of the disadvantages of both the forward and the inverse approach. The method yields as output both a set of potential movement solutions to a given motor task and the net muscular impulses required to produce those movements. The input to the boundary method is a finite and adjustable number of critical target body configurations. In each phase of the motion that …

Extending The Boundary Method For Solving Human Motion Problems Using A 3 Dimensional Coupled Pendulum Model, Avani Janardan Patel

Theses

Mathematical modeling, an evolving area in movement analysis research, couples quantitative measures of human motion with theoretical concepts in physiology and mechanics. Literature reveals two methods to solve for human motion problems, Forward and Inverse Mechanics. In this investigation, a new approach called the Boundaty Method is adopted to solve for human motion. This approach has the advantage of being able to solve for both new motions and the net muscular joint forces required to produce those motions but only at those discrete times and body configurations that are believed to be most crucial for accomplishing the task.

The method …

Particle Size Dependence On Immobilized Molecular Sensors : Assay Of Nucleic Acid Probes Attached To Paramagnetic Particles, Celin Sunny

Theses

Nanotechnology is concerned with materials and systems whose structure and components exhibit novel and significantly improved physical, chemical and biological properties, phenomena and processes due to their nano scale size.

The transition from micro scale to nano scale leads to a number of changes in physical properties, possibly including new physical principles, some of which may be yet to be discovered. One of the major factors in this is the increase in ratio of surface area to volume.

This thesis research uses the increase in ratio of surface area to volume property of going from macro to micro to nano …

Spinning Of Collagen Fibers And Characterizing Thermal, Mechanical, Tensile And Structural Properties, Grace Evangelin Tatagiri

Theses

Collagen is the most important building block in the entire animal world. It plays an important role in regeneration of broken bones and wound healing, also helps grow blood vessels to feed the healing areas. The use of synthetic materials has been extensive, but these materials have there own limits and drawbacks. Poor biocompatibility of these materials is the main issue and often result in inflammations. Hence collagen is being heralded as one of the most appropriate replacement as an implantable material. The reasons being that it is a naturally occurring material, exhibits high biocompatibility low antigenicity and host response. …

Evaluation Of Effect Of Extrusion Process Variables On Mechanical Properties Of Extruded Collagen Tubes And Effect Of Post Extrusion Treatments, Mayank K. Patel

Theses

This study evaluated the effect of extrusion process variable on mechanical properties of extruded collagen tubes made using a specialized extruder, made by ZOKO Corporation of Czechoslovakia. Three extrusion variables were considered; extrusion speed, linear draw rate and rotation speed. Using Taguchi L₄ matrix, a design of experiment (DOE) was run. Two mechanical properties, wall thickness and estimated elastic modulus, were considered as response of this DOE. Data was analyzed statically to evaluate the effect of extrusion variables on both these properties. Result of this study showed that linear draw rate of the extrusion process has the highest influence …

Measurement Of The Effectiveness Of Enhanced External Counterpulsation On Heart Rate Variability For Patients With Myocardial Ischemia, Kripa Jayaraman

Theses

This thesis is a study to measure the changes in heart rate variability due to the activity of the autonomic nervous system caused by the Enhanced External Counterpulsation treatment. The treatment is a non surgical, mechanical procedure that can reduce the symptoms of angina or Congestive Heart Failure, presumably by stimulating the opening, or formation of, small branches of blood vessels (collaterals) to create a natural bypass around narrowed or blocked arteries. It has been proved that rhythms can be markers of normal functional states. Even in the absence of external perturbations, the normal heartbeat is not characterized by clockwise …

Application Of Bootstrap Resampling In Fmri, Arthika Bappal

Theses

This thesis demonstrates the use of the bootstrap resampling technique considering temporal dependency in the fMRI data to determine the reliability and confidence interval of fMRI parameters. Traditionally, the test-retest method has been used to reliably detect active voxels in the fMRI image of the brain, which is based on repetitive experimentation. The main concern with the test-retest method is the reproducibility of data over these multiple repetitions. Fatigue, habituation, motion artifacts, and repositioning errors are few of the factors, which can affect the reproducibility of data.

The conventional bootstrap resampling technique is based on the assumption that the dataset …

Effects Of Sleep Deprivation On Autonomic Nervous System, Jaeyeaon Cho

Theses

Sleep deprivation (SD) has been thought a potential factor to trigger cardiovascular events by increasing the sympathetic nervous system activity. The aim of the present study was to evaluate the relationship between sleep deprivation and the autonomic nervous system activity by means of heart rate variability (HRV) and blood pressure variability (BPV). All data were acquired in the sleep lab of Columbia University.

Data were acquired from the two groups, SD and control. Subjects in the SD group did not sleep for thirty-six hours but subjects in the control group slept at night as usual. There were five different data …

An In Vitro Evaluation Of Tyrosine Derived Polyarylates And Polycarbonate As Polymeric Scaffold For Human Mesenchymal Stem Cells Osteogenic Differentiation, Manish Suresh Godbole

Theses

Human mesenchymal stem cells (hMSCs) obtained from the adult bone marrow are multipotential cells that are capable of differentiating along several lineages. They are readily available and abundant source of cells in the field of tissue engineering. For their use in treating certain connective tissue defect or disorders, their success depends at minimum on the use of scaffolds that support differentiation. Therefore , this thesis details a study that systematically evaluated hMSC differentiation on materials that exhibit gradual range in surface properties as a first study for selecting materials as potential scaffolds. Polycarbonates and polyarylates have combinatorial libraries that exhibit …

Characterization Of Electrospun Dlplga Nanofibers For A Drug Delivery System For Intracranial Tumors And Avms, Kimberly A. Griswold

Theses

Electrospinning processes apply electric fields to a polymer solution in order to produce strands of polymer in the nanoscale range. These polymer fibers are manipulated for their porosity, high surface area, fineness and uniformity. In order to create the ideal drug delivery system for intracranial arteriovenous malformations (AVMs) and tumors, D, L poly-(lactice-poly-glycolide) (DLPLGA) nanofibers were electrospun in a tetrahydrofuran (THF) solvent. Three different concentration ratios of DLPLGA, 85/15, 80/20, and 75/25 were analyzed to obtain the prime base for drug annexation. 1 ,3-bis (2-chloroethyl)- 1 -nitrosourea (BCNU) was then codissolved with the DLPLGA nanofibers to form a homogenous solution, …

Design And Implementation Of Heart Rate Variability Measures In The Time Domain, Binoy John Mathews

Theses

The following study was conducted to design and implement computer programs to derive five time domain and two frequency domain Heart Rate Variability (HRV) measures from 24 hour Holter monitor recordings and to generate activity plots that display the variation of three of the five time domain measures and two frequency domain measures over a period of 24 hours.

Working with known pre and post experimental ECG data taken from a cyclical exercise program, standard parameters in both the time and frequency domains were derived using programs designed in Labview 7.0 engineering software package. Five parameters in the time domain …