Biomedical Engineering and Bioengineering Commons^™

Role Of Ammonia In The Activiation Of Methanol Dehydrogenase/Cytochrome C(L) Enzyme, Ancy Kunjumon

Doctoral Dissertations

Recent advancement in enzyme catalysis has opened ways to design efficient biocatalysts, bio-sensors and bio-fuel cells. An in-depth knowledge about the mechanism of the reaction taking place within the enzymes is of great importance to achieve these goals. In this dissertation, various computation methods are applied to investigate the mechanism behind enzyme catalysis in the presence of compounds called activators.

Methanol dehydrogenase (MDH) is a well-known bio-catalyst that can oxidize excess of methanol from the environment to formaldehyde. The enzyme works well within the bacterial environment, but under in vitro, it loses activity. Ammonia is used as an activator …

Passive Micromixers And Organic Electrochemical Transistors For Biosensor Applications, Senaka Krishna Kanakamedala

Doctoral Dissertations

Fluid handling at the microscale has greatly affected different fields such as biomedical, pharmaceutical, biochemical engineering and environmental monitoring due to its reduced reagent consumption, portability, high throughput, lower hardware cost and shorter analysis time compared to large devices. The challenges associated with mixing of fluids in microscale enabled us in designing, simulating, fabricating and characterizing various micromixers on silicon and flexible polyester substrates. The mixing efficiency was evaluated by injecting the fluids through the two inlets and collecting the sample at outlet. The images collected from the microscope were analyzed, and the absorbance of the color product at the …

Revised Reference Curves For Bone Mineral Content And Areal Bone Mineral Density According To Age And Sex For Black And Non-Black Children: Results Of The Bone Mineral Density In Childhood Study, Babette S. Zemel, Heidi J. Kalkwarf, Vicente Gilsanz, Joan M. Lappe, Sharon Oberfield, John A. Shepherd, Margaret M. Frederick, Xangke Huang, Ming Lu, Soroosh Mahboubi, Thomas N. Hangartner, Karen K. Winer

Biomedical, Industrial & Human Factors Engineering Faculty Publications

Context: Deficits in bone acquisition during growth may increase fracture risk. Assessment of bone health during childhood requires appropriate reference values relative to age, sex, and population ancestry to identify bone deficits.

Objective: The objective of this study was to provide revised and extended reference curves for bone mineral content (BMC) and areal bone mineral density (aBMD) in children.

Design: The Bone Mineral Density in Childhood Study was a multicenter longitudinal study with annual assessments for up to 7 yr.

Setting: The study was conducted at five clinical centers in the United States.

Participants: Two thousand fourteen healthy children (992 …

Application Of Engineered Porosity And Modified Effective Moduli To The Design Of Orthopaedic Implants, John Anthony Choren

Dissertations (1934 -)

Commercially available orthopaedic implants have a bending stiffness (flexural rigidity) that is at least 10 times greater than cortical bone. Effects of this stiffness mismatch have been extensively studied relative to total hip arthroplasty (THA). Clinical experience with THA has shown that stiffness mismatch is the primary cause of accelerated bone resorption due to the stress shielding, resulting in sub-optimal bone loading, aseptic loosening and inadequate bone support for a future revision implant.

Attempts to incorporate design features that reduce the flexural rigidity of implants have yielded inconsistent results or failures due to biomaterial incompatibilities and practical manufacturing complications. The …

Quantitative Evaluation Of Redox Processes In Intact Rat Lungs And Endothelial Cells And The Effect Of Hyperoxia, Zhuohui Gan

Dissertations (1934 -)

A common initial treatment of hypoxemia in patients with lung failure secondary to acute lung injury (e.g., adult respiratory distress syndrome) is oxygen (O₂) therapy (hyperoxia). However, prolonged O₂ therapy causes lung O₂ toxicity, which can further impair lung functions. The rat model of lung O₂ toxicity replicates key features of human lung O₂ toxicity. In addition, rats develop tolerance or susceptibility to 100% O₂ by pre-exposing them to 85% O₂ (hyper-85) or 60% O₂ (hyper-60) for 7 days, respectively. Therefore, the long-term objectives of this study are to elucidate mechanisms …

Incorporating The Aortic Valve Into Computational Fluid Dynamics Models Using Phase-Contrast Mri And Valve Tracking, David C. Wendell

Dissertations (1934 -)

The American Heart Association states about 2% of the general population have a bicuspid aortic valve (BAV). BAVs exist in 80% of patients with aortic coarctation (CoA) and likely influences flow patterns that contribute to long-term morbidity post-surgically. BAV patients tend to have larger ascending aortic diameters, increased risk of aneurysm formation, and require surgical intervention earlier than patients with a normal aortic valve. Magnetic resonance imaging (MRI) has been used clinically to assess aortic arch morphology and blood flow in these patients. These MRI data have been used in computational fluid dynamics (CFD) studies to investigate potential adverse hemodynamics …

Effectiveness Of Group Kickboxing As A Means To Improve Gait And Balance In Individuals With Ms, Kurt Jackson, Kimberly Edginton Bigelow, Christina Cooper, Harold L. Merriman

Mechanical and Aerospace Engineering Faculty Publications

In recent years, there has been a particular emphasis on identifying and delivering appropriate therapeutic interventions that address the significant balance and gait impairments that affect individuals with multiple sclerosis (MS). Group interventions implemented in community settings have been especially of interest, including tai chi classes. Recently, the authors conducted a preliminary study to examine whether group kick-boxing, which requires more vigorous movements, might be a feasible intervention. Initial findings showed promise and led the authors to pursue a more rigorous follow-up study, with the objective of determining whether a 5-week group kickboxing class improved clinical measures of balance and …

Improving Cardiovascular Stent Design Using Patient-Specific Models And Shape Optimization, Timothy J. Gundert

Master's Theses (2009 -)

Stent geometry influences local hemodynamic alterations (i.e. the forces moving blood through the cardiovascular system) associated with adverse clinical outcomes. Computational fluid dynamics (CFD) is frequently used to quantify stent-induced hemodynamic disturbances, but previous CFD studies have relied on simplified device or vascular representations. Additionally, efforts to minimize stent-induced hemodynamic disturbances using CFD models often only compare a small number of possible stent geometries. This thesis describes methods for modeling commercial stents in patient-specific vessels along with computational techniques for determining optimal stent geometries that address the limitations of previous studies.

An efficient and robust method was developed for virtually …

Investigation Of Spatio-Temporal Effects Of Fmri Visual Field Mapping Techniques On V1, John J. Janik

Dissertations (1934 -)

Blood oxygenation level dependent functional magnetic resonance imaging has been used extensively for mapping the representation of the visual field within the human brain. Visual field mapping using fMRI has been used clinically to assess patients with cortical pathology and to plan surgical treatment impacting the visual system. The accuracy of fMRI-based visual field mapping methods needs to be better understood for clinical use. This accuracy can be important for presurgical mapping of brain function near a tumor resection site since inaccurate rendition of the underlying neural function could lead to inappropriate resection of viable brain tissue. The most widely …

Climate Change Policy Could Make Keystone Xl Obsolete, Adam Liska

Adam Liska Papers

Clearly the Keystone XL pipeline threatens both surface and ground water that sustains the agricultural economy of Nebraska, but the projected profitability of tar sands oil and the pipeline operation are dependent on the future economics of climate change. Three recent scientific studies estimate the total carbon intensity of tar sands-based gasoline from Alberta (from both production and burning of the fuel) at an average of roughly 22 percent higher than U.S. gasoline in 2005, with the range of average carbon intensities for tar sands-gasoline at 16 to 27 percent higher than most other sources.

Comparison Of An Ankle-Foot-Orthosis And Neuroprosthesis During Level And Non-Level Walking For Individuals Post-Stroke, Michelle Beverly Gallagher

Master's Theses (2009 -)

This study used gait analysis to compare the efficacy of the two foot drop treatments (ankle-foot-orthosis and neuroprosthesis) and to contrast the stimulation control of the two different neuroprosthesis sensors during level and non-level ambulation of post-stroke individuals.

Eight subjects completed two gait analysis sessions, once while using a study-provided articulated AFO and the other while using a WalkAide. After four weeks of acclimation to the device, each subject performed two minute walking trials on a level, inclined and declined treadmill. Kinematic and heart rate data were collected for all sessions. Plantar pressure and WalkAide tilt, heel loading, and stimulation …

Ranolazine Reduces Ca2+ Overload And Oxidative Stress And Improves Mitochondrial Integrity To Protect Against Ischemia Reperfusion Injury In Isolated Hearts, Mohammed Aldakkak, Amadou K.S. Camara, James S. Heisner, Meiying Yang, David F. Stowe

Biomedical Engineering Faculty Research and Publications

Ranolazine is a clinically approved drug for treating cardiac ventricular dysrhythmias and angina. Its mechanism(s) of protection is not clearly understood but evidence points to blocking the late Na⁺ current that arises during ischemia, blocking mitochondrial complex I activity, or modulating mitochondrial metabolism. Here we tested the effect of ranolazine treatment before ischemia at the mitochondrial level in intact isolated hearts and in mitochondria isolated from hearts at different times of reperfusion. Left ventricular (LV) pressure (LVP), coronary flow (CF), and O₂ metabolism were measured in guinea pig isolated hearts perfused with Krebs-Ringer’s solution; mitochondrial (m) O_{2 …}

Bilateral Assessment Of Functional Tasks For Robot-Assisted Therapy Applications, Michelle J. Johnson, Sarah Wang, Ping Bai, Elaine Strachota, Guennady Tchekanov, Jeff Melbye, John Mcguire

Biomedical Engineering Faculty Research and Publications

This article presents a novel evaluation system along with methods to evaluate bilateral coordination of arm function on activities of daily living tasks before and after robot-assisted therapy. An affordable bilateral assessment system (BiAS) consisting of two mini-passive measuring units modeled as three degree of freedom robots is described. The process for evaluating functional tasks using the BiAS is presented and we demonstrate its ability to measure wrist kinematic trajectories. Three metrics, phase difference, movement overlap, and task completion time, are used to evaluate the BiAS system on a bilateral symmetric (bi-drink) and a bilateral asymmetric (bi-pour) functional task. Wrist …

Motion Analysis Of The Upper Extremities During Lofstrand Crutch-Assisted Gait In Children With Orthopaedic Disabilities, Brooke A. Slavens, Neha Bhagchandani, Mei Wang, Peter A. Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Background

This paper presents a review of current state-of-the-art dynamic systems for quantifying the kinematics and kinetics of the joints of the upper extremities during Lofstrand crutch-assisted gait. The reviewed systems focus on the rehabilitation of children and adults with myelomeningocele (MM), cerebral palsy (CP), spinal cord injury (SCI), and osteogenesis imperfecta (OI). Forearm crutch systems have evolved from models with single- to multi-sensor hardware systems that can incorporate an increasing number of segments that are in compliance with the standards of the International Society of Biomechanics (ISB).

Methods

The initial system developed by our group was a single, six-axis, …

A Model For The Evaluation Of Lower Extremity Kinematics With Integrated Multisegmental Foot Motion, Jason T. Long, Mei Wang, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Background/Purpose

Current models for assessing lower extremity motion during gait benefit from ease of use in the clinical environment. However, underlying assumptions regarding joint location and distal segment motion limit their effectiveness and accuracy. The aim of this study was to develop a model for lower extremity motion analysis, which integrates functional methods for estimating hip joint center (HJC) location and a multisegmental approach to modeling motion of the foot and ankle. The new model is capable of tracking the motion of six segments (pelvis, bilateral thigh, tibia, hindfoot, forefoot, and hallux) during stance and swing.

Methods

Ten healthy young …

Implications Of Arm Restraint On Lower Extremity Kinetics During Gait, Jason T. Long, John B. Groner, Dan C. Eastwood, Timothy R. Dillingham, Prateek Grover, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Background

Literature indicates the importance of the upper extremities in providing stability and propulsion for the body during ambulation. However, the kinetic implications of upper extremity restraint during gait are not as well documented.

Aim

The objective of this study was to examine the effect of arm restraint (unilateral and bilateral) on lower extremity joint kinetics during walking.

Methods

Twenty-three healthy young participants were instrumented for three dimensional motion analysis, and tested in four randomly ordered upper extremity restraint conditions (unrestrained, bilateral restraint, right side restraint, and left side restraint). Temporal spatial parameters and gait/phase-specific lower extremity kinetics and kinematics …

Postoperative Foot And Ankle Kinematics In Rheumatoid Arthritis, Karl Canseco, Carolyne Albert, Jason T. Long, Michael Khazzam, Richard Marks, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Introduction

Rheumatoid arthritis (RA) is a systemic autoimmune disease that can cause weakening and destruction of various joints of the foot and may result in pain and deformity. This clinical presentation can cause eventual loss of function, shoe-wear difficulties, and altered gait patterns.

Purpose

The goal of this prospective study was to quantify changes in temporal-spatial parameters and multisegmental foot and ankle kinematics in a group of patients with RA of the forefoot following surgery.

Methods

Three-dimensional (3-D) motion analysis was conducted preoperatively and postoperatively using a 15-camera Vicon Motion Analysis System (Vicon Motion Systems, Inc.; Lake Forest, CA) on …

Analysis Of Push-Off Power During Locomotion In Children With Type 1 Osteogenesis Imperfecta, Joseph Krzak, Adam Graf, Ann Flanagan, Angela Caudill, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Background/Purpose

Children with type 1 osteogenesis imperfecta (OI) present with abnormal gait characteristics, including reduced power generation during pushoff. However, the exact biomechanical factors associated with reduced power generation are not clearly understood. The purpose of this study was to investigate the biomechanical factors associated with a reduction in ankle power generation in children with type 1 OI.

Methods

Twenty-four participants with type 1 OI (12.5 ± 3.6 years of age) and 24 typically developing children (12.4 ± 3.7 years of age) were evaluated. Three-dimensional gait analysis, isometric plantar flexion strength using dynamometry, and pedobarography were collected on each participant. …

Upper Extremity Joint Dynamics During Walker Assisted Gait: A Quantitative Approach Towards Rehabilitative Intervention, Katherine A. Konop, Kelly M.B. Strifling, Joseph Krzak, Adam Graf, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Background

Many children with spastic diplegic cerebral palsy (CP) use anterior or posterior walkers to aid ambulation. Prolonged use may lead to upper extremity (UE) pathology later in life, including arthritis and joint contractures.

Purpose

This study analyzes the dynamics (kinematics and kinetics) of the shoulder (glenohumeral), elbow, and wrist joints during anterior and posterior walker use. It also examines the dynamic effects of adjusting handle height and grip rotation.

Methods

Ten children with CP underwent motion analysis with upper and lower extremity marker sets and six-degree-of-freedom instrumented walker handles, while using both anterior and posterior walkers. One child underwent …

Current Research And Clinical Applications In Human Motion Analysis, Ken N. Kuo, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

No abstract provided.