Engineering Commons^™

Biomechanical And Radiographic Evaluation Of An Ovine Model For The Human Lumbar Spine, Nina E. Easley, M. Wang, Linda M. Mcgrady, Jeffrey M. Toth

Biomedical Engineering Faculty Research and Publications

While various species of animal models have been used in preclinical investigations of spinal implant devices to assess their biological adaptation and biomechanical performance, few studies have made comprehensive comparisons to validate their suitability of modelling the human spine. The purpose of this study was to assess essential biomechanical behaviours and disc morphology of the ovine lumbar model. Flexibility testing was conducted on the spines (L3—L4 and L4—L5) of nine skeletally matured sheep. Segmental rotation and intradiscal pressure were measured and load sharing between the intervertebral disc and posterior elements were calculated on the basis of a simplified parallel spring …

Contributions Of Online Visual Feedback To The Learning And Generalization Of Novel Finger Coordination Patterns, Xiaolin Liu, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

We explored how people learn new ways to move objects through space using neuromuscular control signals having more degrees of freedom than needed to unambiguously specify object location. Subjects wore an instrumented glove that recorded finger motions. A linear transformation matrix projected joint angle signals (a high-dimensional control vector) onto a two-dimensional cursor position on a video monitor. We assessed how visual information influences learning and generalization of novel finger coordination patterns as subjects practiced using hand gestures to manipulate cursor location. Three groups of test subjects practiced moving a visible cursor between different sets of screen targets. The hand-to-screen …

Katp Channel Openers Have Opposite Effects On Mitochondrial Respiration Under Different Energetic Conditions, Matthias L. Riess, Amadou K.S. Camara, André Heinen, Janis T. Eells, Michele M. Henry, David F. Stowe

Biomedical Engineering Faculty Research and Publications

Mitochondrial (m) K_ATP channel opening has been implicated in triggering cardiac preconditioning. Its consequence on mitochondrial respiration, however, remains unclear. We investigated the effects of two different K_ATP channel openers and antagonists on mitochondrial respiration under two different energetic conditions. Oxygen consumption was measured for complex I (pyruvate/malate) or complex II (succinate with rotenone) substrates in mitochondria from fresh guinea pig hearts. One of two mK_ATP channel openers, pinacidil or diazoxide, was given before adenosine diphosphate in the absence or presence of an mK_ATP channel antagonist, glibenclamide or 5-hydroxydecanoate. Without ATP synthase inhibition, both mK_{ATP …}

Comparison Of Characteristics Between Fatal And Injury Accidents In The Highway Construction Zones, Yingfeng Li, Yong Bai

Civil and Environmental Engineering Faculty Research and Publications

Highway construction zone safety has been a research focus in many countries for many decades. In the United States, regardless of the research efforts devoted, highway construction zones remain a serious safety concern for government agencies, legislatures, the highway industry, and the traveling public. In this study, the fatal and injury accidents between 1992 and 2004 in Kansas highway construction zones were examined systematically and their major characteristics were compared. The results showed significant differences between fatal and injury accidents in the construction zones. The researchers found that: (1) head-on was the dominant type for fatal accidents while rear-end was …

Bioresorbable Polylactide Interbody Implants In An Ovine Anterior Cervical Discectomy And Fusion Model: Three-Year Results, Kevin A. Thomas, Jeffrey M. Toth, Neil R. Crawford, Howard Seim, Lewis L. Shi, Mitchel B. Harris, Anthony S. Turner

Biomedical Engineering Faculty Research and Publications

Study Design.

In vivo study of anterior discectomy and fusion using a bioresorbable 70:30 poly(l-lactide-co-d,l-lactide) interbody implant in an ovine model.

Objective.

To evaluate the efficacy of the polylactide implant to function as an interbody fusion device, and to assess the tissue reaction to the material during the resorption process.

Summary of Background Data.

The use of polylactide as a cervical interbody implant has several potential advantages when compared with traditional materials. Having an elastic modulus very similar to bone minimizes the potential for stress shielding, and as the material resorbs additional loading is transferred to the developing fusion mass. …

Admittance Selection Conditions For Frictionless Force-Guided Assembly Of Polyhedral Parts In Two Single-Point Principal Contacts, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

The admittance of a manipulator can be used to improve robotic assembly. If properly selected, the admittance will regulate a contact force and use it to guide the parts to proper positioning. In previous work, procedures for selecting the appropriate admittance for single principal contact (PC) cases were identified. This paper extends this research for some of the two PC cases-those for which each contact occurs at a single point. The conditions obtained ensure that the motion that results from frictionless contact always instantaneously reduces part misalignment. We show that, for bounded misalignments, if an admittance satisfies the misalignment-reducing conditions …

Mesoscale Calculations Of The Dynamic Behavior Of A Granular Ceramic, John Borg, Tracy J. Vogler

Mechanical Engineering Faculty Research and Publications

Mesoscale calculations have been conducted in order to gain further insight into the dynamic compaction characteristics of granular ceramics. The primary goals of this work are to numerically determine the shock response of granular tungsten carbide and to assess the feasibility of using these results to construct the bulk material Hugoniot. Secondary goals include describing the averaged compaction wave behavior as well as characterizing wave front behavior such as the strain rate versus stress relationship and statistically describing the laterally induced velocity distribution. The mesoscale calculations were able to accurately reproduce the experimentally determined Hugoniot slope but under predicted the …

Induction Machine Broken Bar And Stator Short-Circuit Fault Diagnostics Based On Three Phase Stator Current Envelopes, Aderiano M. Da Silva, Richard J. Povinelli, Nabeel Demerdash

Electrical and Computer Engineering Faculty Research and Publications

A new method for the fault diagnosis of a broken rotor bar and interturn short circuits in induction machines (IMs) is presented. The method is based on the analysis of the three-phase stator current envelopes of IMs using reconstructed phase space transforms. The signatures of each type of fault are created from the three-phase current envelope of each fault. The resulting fault signatures for the new so-called ldquounseen signalsrdquo are classified using Gaussian mixture models and a Bayesian maximum likelihood classifier. The presented method yields a high degree of accuracy in fault identification as evidenced by the given experimental results, …

Portland Cement Concrete Pavement Over Rubblized Pcc, James Crovetti

Transportation Reports with the Wisconsin Department of Transportation

This report has presented findings of research conducted to determine the viability of constructing Portland cement concrete pavements over rubblized PCC. Rubblization of aged PCC pavements is a common technique for in-place recycling of these pavements. For the vast majority of applications, the rubblized PCC layer is surfaced with hot mix asphalt (HMA). The use of Portland cement concrete as a surfacing material offers designers another option which may provide good performance and be cost-effective under certain conditions.

The current concrete pavement design procedures utilized by WisDOT allow for the incorporation of a rubblized PCC base layer and an increase …

Acoustic Model Adaptation For Ortolan Bunting (Emberiza Hortulana L.) Song-Type Classification, Jidong Tao, Michael T. Johnson, Tomasz S. Osiejuk

Dr. Dolittle Project: A Framework for Classification and Understanding of Animal Vocalizations

Automatic systems for vocalization classification often require fairly large amounts of data on which to train models. However, animal vocalization data collection and transcription is a difficult and time-consuming task, so that it is expensive to create large data sets. One natural solution to this problem is the use of acoustic adaptation methods. Such methods, common in human speech recognition systems, create initial models trained on speaker independent data, then use small amounts of adaptation data to build individual-specific models. Since, as in human speech, individual vocal variability is a significant source of variation in bioacoustic data, acoustic model adaptation …

An Improved Snr Estimator For Speech Enhancement, Yao Ren, Michael T. Johnson

Dr. Dolittle Project: A Framework for Classification and Understanding of Animal Vocalizations

In this paper, we propose an MMSE a priori SNR estimator for speech enhancement. This estimator has similar benefits to the well-known decision-directed approach, but does not require an ad-hoc weighting factor to balance the past a priori SNR and current ML SNR estimate with smoothing across frames. Performance is evaluated in terms of estimation error and segmental SNR using the standard logSTSA speech enhancement method. Experimental results show that, in contrast with the decision-directed estimator and ML estimator, the proposed SNR estimator can help enhancement algorithms preserve more weak speech information and efficiently suppress musical noise.

An Effect Of Relative Motion On Trajectory Discrimination, Scott A. Beardsley, Lucia M. Vaina

Biomedical Engineering Faculty Research and Publications

Psychophysical studies point to the existence of specialized mechanisms sensitive to the relative motion between an object and its background. Such mechanisms would seem ideal for the motion-based segmentation of objects; however, their properties and role in processing the visual scene remain unclear. Here we examine the contribution of relative motion mechanisms to the processing of object trajectory. In a series of four psychophysical experiments we examine systematically the effects of relative direction and speed differences on the perceived trajectory of an object against a moving background. We show that background motion systematically influences the discrimination of object direction. …

Leg Sympathetic Response To Noxious Skin Stimuli Is Similar In High And Low Level Human Spinal Cord Injury, M. Kevin Garrison, Alexander V. Ng, Brian D. Schmit

Biomedical Engineering Faculty Research and Publications

Objective

To determine if sympathetically mediated vasoconstriction in the lower extremities is injury level dependent. Although sympathetic responses have been measured in the limbs of people with high and low level SCI using blood flow measurements, including Doppler ultrasound and venous plethysmography, a direct comparison between injury levels has not been made.

Methods

Volunteers with chronic SCI were grouped according to injury level. Above T6: high level (HL, n = 7), and T6 and below: low level (LL, n = 6). All subjects had complete motor and sensory loss. Leg arterial flows were recorded by venous occlusion plethysmography, and continuous …

Mineral Trioxide Aggregate Material Use In Endodontic Treatment: A Review Of The Literature, Howard W. Roberts, Jeffrey M. Toth, David W. Berzins, David G. Charlton

Biomedical Engineering Faculty Research and Publications

Objective

The purpose of this paper was to review the composition, properties, biocompatibility, and the clinical results involving the use of mineral trioxide aggregate (MTA) materials in endodontic treatment.

Methods

Electronic search of scientific papers from January 1990 to August 2006 was accomplished using PubMed and Scopus search engines (search terms: MTA, GMTA, WMTA, mineral AND trioxide AND aggregate).

Results

Selected exclusion criteria resulted in 156 citations from the scientific, peer-reviewed dental literature. MTA materials are derived from a Portland cement parent compound and have been demonstrated to be biocompatible endodontic repair materials, with its biocompatible nature strongly suggested by …

Mechanical Behavior And Failure Analysis Of Prosthetic Retaining Screws After Long‐Term Use In Vivo. Part 3: Preload And Tensile Fracture Load Testing, Youssef S. Al Jabbari, Raymond Fournelle, Gerald J. Ziebert, Jeffrey M. Toth, Anthony Iacopino

Biomedical Engineering Faculty Research and Publications

Purpose: The aim of this study was to determine the preload and tensile fracture load values of prosthetic retaining screws after long‐term use in vivo compared to unused screws (controls). Additionally, the investigation addressed whether the preload and fracture load values of prosthetic retaining screws reported by the manufacturer become altered after long‐term use in vivo.

Materials and Methods: For preload testing, 10 new screws (controls) from Nobel Biocare (NB) and 73 used retaining screws [58 from NB and 15 from Sterngold (SG)] were subjected to preload testing. For tensile testing, eight controls from NB and 58 used retaining screws …

Mechanical Behavior And Failure Analysis Of Prosthetic Retaining Screws After Long‐Term Use In Vivo. Part 4: Failure Analysis Of 10 Fractured Retaining Screws Retrieved From Three Patients, Youssef S. Al Jabbari, Raymond Fournelle, Gerald J. Ziebert, Jeffrey M. Toth, Anthony Iacopino

Biomedical Engineering Faculty Research and Publications

Purpose: The aim of this study was to perform a failure analysis on fractured prosthetic retaining screws after long‐term use in vivo. Additionally, the study addresses the commonly asked question regarding whether complex repeated functional occlusal forces initiate fatigue‐type cracks in prosthetic retaining screws.

Materials and Methods: Ten fractured prosthetic retaining screws retrieved from three patients treated with fixed detachable hybrid prostheses were subjected to a failure analysis. In patients 1 and 2, the middle three retaining screws of the prostheses were found fractured at retrieval time after they had been in service for 20 and 19 months, respectively. In …

Sorption-Induced Static Bending Of Microcantilevers Coated With Viscoelastic Material, Michael J. Wenzel, Fabien Josse, Stephen M. Heinrich, Edwin E. Yaz, P. G. Datskos

Civil and Environmental Engineering Faculty Research and Publications

Absorption of a chemical analyte into a polymercoating results in an expansion governed by the concentration and type of analyte that has diffused into the bulk of the coating. When the coating is attached to a microcantilever, this expansion results in bending of the device. Assuming that absorption (i.e., diffusion across the surface barrier into the bulk of the coating) is Fickian, with a rate of absorption that is proportional to the difference between the absorbed concentration and the equilibrium concentration, and the coating is elastic, the bending response of the coated device should exhibit a first-order behavior. However, for …

Analysis Of Resonating Microcantilevers Operating In A Viscous Liquid Environment, Cyril Vančura, Isabelle Dufour, Stephen M. Heinrich, Fabien Josse, Andreas Hierlemann

Civil and Environmental Engineering Faculty Research and Publications

The characteristics of resonant cantilevers in viscous liquids are analyzed. Various rectangular cantilevers geometries are studied in pure water, glycerol and ethanol solutions of different concentrations, and the results are described in terms of the added displaced liquid mass and the liquid damping force for both, the resonance frequency and the quality factor (Q-factor). Experimental results using a set of magnetically actuated resonant cantilevers vibrating in the out-of-plane (“weak-axis bending”) mode are presented and compared to theoretical calculations. The importance of the study is in the use of resonant cantilevers as biochemical sensors in liquid environments.

Site-Specific Effects Of Pecam-1 On Atherosclerosis In Ldl Receptor-Deficient Mice, Shikha Arora, Brian Boylan, Reema Goel, Benjamin R. Schrank, Barbara Fleming, Rose Ann Fleming, Hiroto Mirura, Peter J. Newman, Robert C. Molthen, Debra K. Newman

Biomedical Engineering Faculty Research and Publications

Objective—Atherosclerosis is a vascular disease that involves lesion formation at sites of disturbed flow under the influence of genetic and environmental factors. Endothelial expression of adhesion molecules that enable infiltration of immune cells is important for lesion development. Platelet/endothelial cell adhesion molecule-1 (PECAM-1; CD31) is an adhesion and signaling receptor expressed by many cells involved in atherosclerotic lesion development. PECAM-1 transduces signals required for proinflammatory adhesion molecule expression at atherosusceptible sites; thus, it is predicted to be proatherosclerotic. PECAM-1 also inhibits inflammatory responses, on which basis it is predicted to be atheroprotective.

Methods and Results—We evaluated herein the effect of …

Overview Of Biocreative Ii Gene Mention Recognition, Larry Smith, Lorraine K. Tanabe, Rie Johnson Nee Ando, Cheng-Ju Kuo, I-Fang Chung, Chun-Nan Hsu, Yu-Shi Lin, Roman Klinger, Christoph M. Friedrich, Kuzman Ganchev, Manabu Torii, Hongfang Liu, Barry Haddow, Craig A. Struble, Richard J. Povinelli, Andreas Vlachos, William A. Baumgartner, Lawrence Hunter, Bob Carpenter, Richard Tzong-Han Tsai, Hong-Jie Dai, Feng Liu, Yifei Chen, Chengjie Sun, Sophia Katrenko, Pieter Adriaans, Christian Blaschke, Rafael Torres, Mariana Neves, Preslav Nakov, Anna Divoli, Manuel Maña-López, Jacinto Mata, W John Wilbur

Electrical and Computer Engineering Faculty Research and Publications

Nineteen teams presented results for the Gene Mention Task at the BioCreative II Workshop. In this task participants designed systems to identify substrings in sentences corresponding to gene name mentions. A variety of different methods were used and the results varied with a highest achieved F₁ score of 0.8721. Here we present brief descriptions of all the methods used and a statistical analysis of the results. We also demonstrate that, by combining the results from all submissions, an F score of 0.9066 is feasible, and furthermore that the best result makes use of the lowest scoring submissions.

Prolonged Quadriceps Activity Following Imposed Hip Extension: A Neurophysiological Mechanism For Stiff-Knee Gait?, Michael D. Lewek, T. George Hornby, Yasin Y. Dhaher, Brian D. Schmit

Biomedical Engineering Faculty Research and Publications

The biomechanical characteristics of stiff knee gait following neurological injury include decreased knee flexion velocity at toe-off, which may be due to exaggerated quadriceps activity. The neuromuscular mechanism underlying this abnormal activity is unclear, although hyperexcitable heteronymous reflexes may be a source of impaired coordination. The present study examines the contribution of reflex activity from hip flexors on knee extensors following stroke and its association with reduced swing-phase knee flexion during walking. Twelve individuals poststroke and six control subjects were positioned in supine on a Biodex dynamometer with the ankle and knee held in a static position. Isolated hip extension …

Separate Adaptive Mechanisms For Controlling Trajectory And Final Position In Reaching, Robert A. Scheidt, Claude Ghez

Biomedical Engineering Faculty Research and Publications

We examined control of the hand's trajectory (direction and shape) and final equilibrium position in horizontal planar arm movements by quantifying transfer of learned visuomotor rotations between two tasks that required aiming the hand to the same spatial targets. In a trajectory-reversal task (“slicing”), the hand reversed direction within the target and returned to the origin. In a positioning task (“reaching”), subjects moved the hand to the target and held it there; cursor feedback was provided only after movement ended to isolate learning of final position from trajectory direction. We asked whether learning acquired in one task would transfer to …

Different Learned Coordinate Frames For Planning Trajectories And Final Positions In Reaching, Claude Ghez, Robert A. Scheidt, Hank Heijink

Biomedical Engineering Faculty Research and Publications

We previously reported that the kinematics of reaching movements reflect the superimposition of two separate control mechanisms specifying the hand's spatial trajectory and its final equilibrium position. We now asked whether the brain maintains separate representations of the spatial goals for planning hand trajectory and final position. One group of subjects learned a 30° visuomotor rotation about the hand's starting point while performing a movement reversal task (“slicing”) in which they reversed direction at one target and terminated movement at another. This task required accuracy in acquiring a target mid-movement. A second group adapted while moving to—and stabilizing at—a single …

Mechanical Behavior And Failure Analysis Of Prosthetic Retaining Screws After Long‐Term Use In Vivo. Part 2: Metallurgical And Microhardness Analysis, Youssef S. Al Jabbari, Raymond Fournelle, Gerald J. Ziebert, Jeffrey M. Toth, Anthony Iacopino

Biomedical Engineering Faculty Research and Publications

Abstract

Purpose: This study involved testing and analyzing multiple retrieved prosthetic retaining screws after long‐term use in vivo to: (1) detect manufacturing defects that could affect in‐service behavior; (2) characterize the microstructure and alloy composition; and (3) further characterize the wear mechanism of the screw threads.

Materials and Methods: Two new (control) screws from Nobel Biocare (NB) and 18 used (in service 18–120 months) retaining screws [12 from NB and 6 from Sterngold (SG)] were: (1) metallographically examined by light microscopy and scanning electron microscopy (SEM) to determine the microstructure; (2) analyzed by energy dispersive X‐ray (EDX) microanalysis to determine …

Mechanical Behavior And Failure Analysis Of Prosthetic Retaining Screws After Long‐Term Use In Vivo. Part 1: Characterization Of Adhesive Wear And Structure Of Retaining Screws, Youssef S. Al Jabbari, Raymond Fournelle, Gerald J. Ziebert, Jeffrey M. Toth, Anthony Iacopino

Biomedical Engineering Faculty Research and Publications

Purpose: The general aim of this study and those presented in Parts 2–4 of this series was to characterize the structure, properties, wear, and fracture of prosthetic retaining screws in fixed detachable hybrid prostheses after long‐term use in vivo. This part of the overall investigation addresses whether there are differences in thread wear between the screws closest to the fulcrum and those that are farthest from the fulcrum in fixed detachable hybrid prostheses.

Materials and Methods: The total number of prosthetic retaining screws used in this study was 100 (10 new and 90 used). New screws (controls) from Nobel Biocare …

Airway Strain During Mechanical Ventilation In An Intact Animal Model, Scott W. Sinclair, Robert C. Molthen, Steven Thomas Haworth, Christopher A. Dawson, Christopher M. Waters

Biomedical Engineering Faculty Research and Publications

Rationale: Mechanical ventilation with large tidal volumes causes ventilator-induced lung injury in animal models. Little direct evidence exists regarding the deformation of airways in vivo during mechanical ventilation, or in the presence of positive end-expiratory pressure (PEEP).

Objectives: To measure airway strain and to estimate airway wall tension during mechanical ventilation in an intact animal model.

Methods: Sprague-Dawley rats were anesthetized and mechanically ventilated with tidal volumes of 6, 12, and 25 cm³/kg with and without 10–cm H₂O PEEP. Real-time tantalum bronchograms were obtained for each condition, using microfocal X-ray imaging. Images were …

Rapid Detection Of Analytes With Improved Selectivity Using Coated Microcantilever Chemical Sensors And Estimation Theory, Michael J. Wenzel, Fabien Josse Phd, Edwin E. Yaz, Stephen M. Heinrich, P. G. Datskos

Civil and Environmental Engineering Faculty Research and Publications

Rapid detection of analytes with improved selectivity is achieved though the use of estimation theory to analyze the response of polymer-coated microcantilever chemical sensors. In general, chemical sensors exhibit partial selectivity and can have relatively long response times. Using estimation theory, it is possible to make short-term response predictions from past data. This makes it possible to use the transient information (response time), often unique to an analyte/coating pair, to achieve an improvement in analyte species recognition while simultaneously allowing for a reduction in the time required for identification and quantification. An extended Kalman filter is used as a recursive …

Chronic Hypoxia-Induced Pulmonary Hypertension Does/Does Not Lead To Loss Of Pulmonary Vasculature, Marlene Rabinovitch, Naomi Chesler, Robert C. Molthen

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Diagnosis Of Inter-Turn Short Circuit For A Polyphase Induction Motor In Closed-Loop Vector-Controlled Drives, Ahmed Sayed-Ahmed, Gennadi Y. Sizov, Nabeel Demerdash

Electrical and Computer Engineering Faculty Research and Publications

The main objective of this paper is to develop and experimentally verify a new technique to detect an inter-turn short circuit in one phase of a stator winding of an induction motor energized from a vector-controlled drive. This is in order to overcome the fault masking difficulties associated with the concept of depending on the actual magnetic field pendulous oscillation between the conventional voltage and current space vectors with respect to a reference that is unaltered by the compensation action of the drive. This technique is based on the flux pendulous oscillation phenomenon. This flux pendulous oscillation is also described …

A Light-Weight Event-Driven Protocol For Sensor Clustering In Wireless Camera Networks, Henry Medeiros, Johnny Park, Avinash Kak

Electrical and Computer Engineering Faculty Research and Publications

We propose a light-weight event-driven protocol for wireless camera networks to allow for formation and propagation of clusters of cameras for the purpose of collaborative processing during object tracking. Cluster formation is triggered by the detection of objects with specific features. Our protocol allows for simultaneous formation and propagation of multiple clusters. Cameras being directional devices, more than one cluster may track a single object since groups of cameras outside each others communication range may see the same object. Entry into a cluster and cluster membership maintenance require a sensor node to confirm the presence of features of the object …