Engineering Commons^™

Different Motion Cues Are Used To Estimate Time-To-Arrival For Frontoparallel And Loming Trajectories, Finnegan J. Calabro, Scott A. Beardsley, Lucia M. Vaina

Biomedical Engineering Faculty Research and Publications

Estimation of time-to-arrival for moving objects is critical to obstacle interception and avoidance, as well as to timing actions such as reaching and grasping moving objects. The source of motion information that conveys arrival time varies with the trajectory of the object raising the question of whether multiple context-dependent mechanisms are involved in this computation. To address this question we conducted a series of psychophysical studies to measure observers’ performance on time-to-arrival estimation when object trajectory was specified by angular motion (“gap closure” trajectories in the frontoparallel plane), looming (colliding trajectories, TTC) or both (passage courses, TTP). We measured performance …

Quantifying The Tibiofemoral Joint Space Using X-Ray Tomosynthesis, Benjamin Kalinosky, John M. Sabol, Kelly Piacsek, Beth Heckel, Taly Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

Purpose: Digital x-ray tomosynthesis (DTS) has the potential to provide 3D information about the knee joint in a load-bearing posture, which may improve diagnosis and monitoring of knee osteoarthritis compared with projection radiography, the current standard of care. Manually quantifying and visualizing the joint space width (JSW) from 3D tomosynthesis datasets may be challenging. This work developed a semiautomated algorithm for quantifying the 3D tibiofemoral JSW from reconstructed DTS images. The algorithm was validated through anthropomorphic phantom experiments and applied to three clinical datasets. Methods: A user-selected volume of interest within the reconstructed DTS volume was enhanced with 1D multiscale …

High Temperature Thermodynamic Properties Of Znte(S), Robert F. Brebrick

Mechanical Engineering Faculty Research and Publications

We have gathered the partial pressure, Knudsen cell, and emf measurements on ZnTe(s) from which the Gibbs energy of formation can be calculated. Published partial pressures of diatomic tellurium have been adjusted to take account of a subsequently published third law analysis of tellurium. The equation used to calculate the total pressure from the rate of mass loss from an extensive set of Knudsen cell measurements has been corrected to give a 5% increase in total pressure and the Gibbs energy of formation has been recalculated. A high temperature heat capacity for ZnTe(s) has been selected from the published data. …

Mechanical Characterization Of Fourth Generation Composite Humerus, Prateek Grover, Carolyne Albert, Mei Wang, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Mechanical data on upper extremity surrogate bones, supporting use as biomechanical tools, is limited. The objective of this study was to characterize the structural behaviour of the fourth-generation composite humerus under simulated physiologic bending, specifically, stiffness, rigidity, and mid-diaphysial surface strains. Three humeri were tested in four-point bending, in anatomically defined anteroposterior (AP) and mediolateral (ML) planes. Stiffness and rigidity were derived using load–displacement data. Principal strains were determined at the anterior, posterior, medial, and lateral surfaces in the humeral mid-diaphysial transverse plane of one specimen using stacked rosettes. Linear structural behaviour was observed within the test range. Average stiffness …

Effect Of Sensory Feedback From The Proximal Upper Limb On Voluntary Isometric Finger Flexion And Extension In Hemiparetic Stroke Subjects, Gilles Hoffmann, Brian D. Schmit, Jennifer H. Kahn, Derek G. Kamper

Biomedical Engineering Faculty Research and Publications

This study investigated the potential influence of proximal sensory feedback on voluntary distal motor activity in the paretic upper limb of hemiparetic stroke survivors and the potential effect of voluntary distal motor activity on proximal muscle activity. Ten stroke subjects and 10 neurologically intact control subjects performed maximum voluntary isometric flexion and extension, respectively, at the metacarpophalangeal (MCP) joints of the fingers in two static arm postures and under three conditions of electrical stimulation of the arm. The tasks were quantified in terms of maximum MCP torque [MCP flexion (MCP_flex) or MCP extension (MCP_ext)] and activity …

Patterns Of Hypermetria And Terminal Cocontraction During Point-To-Point Movements Demonstrate Independent Action Of Trajectory And Postural Controllers, Robert A. Scheidt, Claude Ghez, Supriya Asnani

Biomedical Engineering Faculty Research and Publications

We examined elbow muscle activities and movement kinematics to determine how subjects combine elementary control actions in performing movements with one and two trajectory segments. In reaching, subjects made a rapid elbow flexion to a visual target before stabilizing the limb with either a low or a higher level of elbow flexor/extensor coactivity (CoA), which was cued by target diameter. Cursor diameter provided real-time biofeedback of actual muscle CoA. In reversing, the limb was to reverse direction within the target and return to the origin with minimal CoA. We previously reported that subjects overshoot the goal when attempting a reversal …

Sensing With The Motor Cortex, Nicholas G. Hatsopoulos, Aaron J. Suminski

Biomedical Engineering Faculty Research and Publications

The primary motor cortex is a critical node in the network of brain regions responsible for voluntary motor behavior. It has been less appreciated, however, that the motor cortex exhibits sensory responses in a variety of modalities including vision and somatosensation. We review current work that emphasizes the heterogeneity in sensorimotor responses in the motor cortex and focus on its implications for cortical control of movement as well as for brain-machine interface development.

Gait Verification Using Knee Acceleration Signals, L. W. Hang, C. Y. Hong, C. W. Yen, D. J. Chang, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

A novel gait recognition method for biometric applications is proposed. The approach has the following distinct features. First, gait patterns are determined via knee acceleration signals, circumventing difficulties associated with conventional vision-based gait recognition methods. Second, an automatic procedure to extract gait features from acceleration signals is developed that employs a multiple-template classification method. Consequently, the proposed approach can adjust the sensitivity and specificity of the gait recognition system with great flexibility. Experimental results from 35 subjects demonstrate the potential of the approach for successful recognition. By setting sensitivity to be 0.95 and 0.90, the resulting specificity ranges from 1 …

Electrostatically Tunable Meta-Atoms Integrated With In Situ Fabricated Mems Cantilever Beam Arrays, Ronald A. Coutu Jr., Peter J. Collins, Elizabeth A. Moore, Derrick Langley, Matthew E. Jussaume, Lavern A. Starman

Electrical and Computer Engineering Faculty Research and Publications

Two concentric split ring resonators (SRRs) or meta-atoms designed to have a resonant frequency of 14 GHz are integrated with microelectromechanical systems cantilever arrays to enable electrostatic tuning of the resonant frequency. The entire structure was fabricated monolithically to improve scalability and minimize losses from externally wire-bonded components. A cantilever array was fabricated in the gap of both the inner and outer SRRs and consisted of five evenly spaced beams with lengths ranging from 300 to 400 μm. The cantilevers pulled in between 15 and 24 V depending on the beam geometry. Each pulled-in beam increased the SRR gap capacitance …

Stability And Minimum Cost Analysis Of A Discrete-Time Disturbance Accommodation Controller, Katrina H. Barhouse

Master's Theses (2009 -)

Disturbance accommodation control (DAC) is a method for designing a controller that minimizes the effects of disturbances of known waveform type, but with unknown arrival time, duration or magnitude. Systems that do not have a control term in the measurement equation pose a particular challenge for DAC design. A disturbance accommodation controller for these types of systems was previously developed by defining a pseudo-output consisting of the current output and previous control input terms with weighting coefficients.

The objective of the present work is to analyze the stability and performance of the discrete- time disturbance accommodation controller for systems without …

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 …

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 …

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 …

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 …

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. …

A Compressed Sensing Algorithm For Sparse-View Pinhole Single Photon Emission Computed Tomography, Paul Arthur Wolf, Emil Y. Sidky, Taly Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

Single Photon Emission Computed Tomography (SPECT) systems are being developed with multiple cameras and without gantry rotation to provide rapid dynamic acquisitions. However, the resulting data is angularly undersampled, due to the limited number of views. We propose a novel reconstruction algorithm for sparse-view SPECT based on Compressed Sensing (CS) theory. The algorithm models Poisson noise by modifying the Iterative Hard Thresholding algorithm to minimize the Kullback-Leibler (KL) distance by gradient descent. Because the underlying objects of SPECT images are expected to be smooth, a discrete wavelet transform (DWT) using an orthogonal spline wavelet kernel is used as the sparsifying …

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 …

A Quantitative Study Of Robustness Characteristics In Steel Framed Structures, Christopher Herman Raebel

Dissertations (1934 -)

Robustness is a desirable property in any structural design. Robustness may be thought of as the building's inherent structural ability to resist loads other than those anticipated during design. Examples of unanticipated loads are damage to a column or beam due to impact; damage due to the concussion of a blast; strength reduction due to extreme heat during a fire; and localized accidental overload of a beam or column. Each of these events, although very different in their nature, has one major point in common; in each case the path of load resistance changes in a way that was not …

Analysis Of An Air-Spaced Patch Antenna Near 1800 Mhz, Hermine Nathalie Akouemo Kengmo Kenfack

Master's Theses (2009 -)

Microstrip antennas are a type of printed antenna which consists of a patch on top of a grounded substrate. A major limitation for the performance of the patch antenna is the dielectric substrate. The idea of using air as dielectric was therefore considered to overcome that limitation because air has the lowest permittivity and no loss. The goal of this work is to build an air-spaced patch antenna, with the minimum resonant frequency at 1800 MHz and with a return loss of at least 10 dB.

This work is novel because the air-spaced patch antenna has not been extensively studied. …

Investigation Of Aluminum Equation Of State Generation, Aaron Ward

Master's Theses (2009 -)

There are many forms and methods to construct equations of state, EOSs. These methods are usually tailored for the particular problem of interest. Here, the EOSs of interest are those used in modeling shock responses. These EOSs cover a wide range of physical characteristics such as detonation and explosions, armor and anti-armor materials, and space structures protection. Aluminum will be the primary focus of this work. Aluminum was chosen because it has been studied in great length in the shock regime and is a common component in shock experiments and space type vehicles.

Droplet Behavior In Dense, Low Velocity Aerosols, Alexander Polley

Master's Theses (2009 -)

Rapid compression machines (RCM) are laboratory devices used to measure gas-phase fuel reactivity at conditions relevant to combustion engines. Test mixtures are generally prepared by rapidly compressing a gas phase fuel+oxidizer+diluent mixture to high pressure and temperature (e.g., 10-50 bar, 650-1000 K). It is extremely challenging to utilize diesel-relevant liquid fuels in these devices due to their involatility. One proposed method involves the delivery of an aerosol of suspended fuel droplets (∼ 0.1 mL_fuel/L_gas at stoichiometric fuel loading) to the machine. The compression stroke of the RCM subsequently heats the gas phase of the aerosol thereby achieving …

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 …

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 …

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 …

Disaggregating Time Series Data For Energy Consumption By Aggregate And Individual Customer, Steven Vitullo

Dissertations (1934 -)

This dissertation generalizes the problem of disaggregating time series data and describes the disaggregation problem as a mathematical inverse problem that breaks up aggregated (measured) time series data that is accumulated over an interval and estimates its component parts.

We describe five different algorithms for disaggregating time series data: the Naive, Time Series Reconstruction (TSR), Piecewise Linear Optimization (PLO), Time Series Reconstruction with Resampling (RS), and Interpolation (INT). The TSR uses least squares and domain knowledge of underlying correlated variables to generate underlying estimates and handles arbitrarily aggregated time steps and non-uniformly aggregated time steps. The PLO performs an adjustment …

Tertiary-Treated Municipal Wastewater Is A Significant Point Source Of Antibiotic Resistance Genes Into Duluth-Superior Harbor, Patrick J. Mcnamara, Tucker R. Burch, Timothy M. Lapara, David T. Tan, Mi Yan, Jessica J. Eichmiller

Civil and Environmental Engineering Faculty Research and Publications

In this study, the impact of tertiary-treated municipal wastewater on the quantity of several antibiotic resistance determinants in Duluth-Superior Harbor was investigated by collecting surface water and sediment samples from 13 locations in Duluth-Superior Harbor, the St. Louis River, and Lake Superior. Quantitative PCR (qPCR) was used to target three different genes encoding resistance to tetracycline (tet(A), tet(X), and tet(W)), the gene encoding the integrase of class 1 integrons (intI1), and total bacterial abundance (16S rRNA genes) as well as total and human fecal contamination levels (16S rRNA genes specific to the genus Bacteroides …

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 …