Engineering Commons^™

Depleted Energy Charge And Increased Pulmonary Endothelial Permeability Induced By Mitochondrial Complex I Inhibition Are Mitigated By Coenzyme Q1 In The Isolated Perfused Rat Lung, Robert D. Bongard, Ke Yan, Raymond G. Hoffmann, Said H. Audi, Xiao Zhang, Brian J. Lindemer, Mary I. Townsley, Marilyn P. Merker

Biomedical Engineering Faculty Research and Publications

Mitochondrial dysfunction is associated with various forms of lung injury and disease that also involve alterations in pulmonary endothelial permeability, but the relationship, if any, between the two is not well understood. This question was addressed by perfusing isolated intact rat lung with a buffered physiological saline solution in the absence or presence of the mitochondrial complex I inhibitor rotenone (20 μM). Compared to control, rotenone depressed whole lung tissue ATP from 5.66±0.46 (SEM) to 2.34±0.15 µmol·g⁻¹ dry lung, with concomitant increases in the ADP:ATP and AMP:ATP ratios. Rotenone also increased lung perfusate lactate (from 12.36±1.64 to 38.62±3.14 µmol·15 …

Exploiting Contextual Information For Prosodic Event Detection Using Auto-Context, Junhong Zhao, Wei-Qiang Zhang, Hua Yang, Michael T. Johnson, Jia Liu, Shanhong Xia

Electrical and Computer Engineering Faculty Research and Publications

Prosody and prosodic boundaries carry significant information regarding linguistics and paralinguistics and are important aspects of speech. In the field of prosodic event detection, many local acoustic features have been investigated; however, contextual information has not yet been thoroughly exploited. The most difficult aspect of this lies in learning the long-distance contextual dependencies effectively and efficiently. To address this problem, we introduce the use of an algorithm called auto-context. In this algorithm, a classifier is first trained based on a set of local acoustic features, after which the generated probabilities are used along with the local features as contextual information …

The Effects Of Gantry Tilt On Breast Dose And Image Noise In Cardiac Ct, Michael Hoppe, Diksha Gandhi, Grant Stevens, Dennis Foley, Taly Gilat-Schmidt

Biomedical Engineering Faculty Research and Publications

Purpose:

This study investigated the effects of tilted-gantry acquisition on image noise and glandular breast dose in females during cardiac computed tomography (CT) scans. Reducing the dose to glandular breast tissue is important due to its high radiosensitivity and limited diagnostic significance in cardiac CT scans.

Methods:

Tilted-gantry acquisition was investigated through computer simulations and experimental measurements. Upon IRB approval, eight voxelized phantoms were constructed from previously acquired cardiac CT datasets. Monte Carlo simulations quantified the dose deposited in glandular breast tissue over a range of tilt angles. The effects of tilted-gantry acquisition on breast dose were measured on a …

Finite Element Analysis Of Frp Debonding Failure At The Tip Of Flexural/Shear Crack In Concrete Beam, Tayyebeh Mohammadi, Baolin Wan, Kent Harries

Civil and Environmental Engineering Faculty Research and Publications

One of the most common failure modes of strengthened RC beams with externally bonded FRP is intermediate crack (IC) debonding of FRP initiated at the tip of flexural/shear cracks. This study presents a method, using extended finite element method (XFEM), to model IC debonding in an FRP-strengthened concrete beam. In XFEM, as soon as a damage initiation criterion is reached in an element, additional degrees of element freedom are added to model crack initiation. Crack propagation is then modeled using fracture energy criterion. This method can be used to simulate debonding failure along an arbitrary, solution-dependent path without the requirement …

Heavy Vehicle Performance During Recovery From Forced-Flow Urban Freeway Conditions Due To Incidents, Work Zones And Recurring Congestion, Alexander Drakopoulos, Yue Liu, Alan Horowitz

Civil and Environmental Engineering Faculty Research and Publications

Information contained in the Highway Capacity Manual on the influence heavy vehicles have on freeway traffic operations has been based on few field data collection efforts and relied mostly on traffic simulation efforts. In the 2010 Manual heavy vehicle impact is evaluated based on “passenger car equivalent” values for buses, recreational vehicles and trucks. These values were calibrated for relatively uncongested freeway conditions (levels of service A through C) since inadequate field data on heavy vehicle behavior under congested conditions were available. A number of field data collection efforts, that were not included in deriving the passenger car equivalent values …

Calculation Of Magnet Losses In Concentrated-Winding Permanent-Magnet Synchronous Machines Using A Computationally Efficient Finite-Element Method, Peng Zhang, Gennadi Y. Sizov, Jiangbiao He, Dan M. Ionel, Nabeel Demerdash

Electrical and Computer Engineering Faculty Research and Publications

The proposed hybrid method combines computationally efficient finite-element analysis (CE-FEA) with a new analytical formulation for eddy-current losses in the permanent magnets (PMs) of sine-wave current-regulated brushless synchronous motors. The CE-FEA only employs a reduced set of magnetostatic solutions yielding substantial reductions in the computational time, as compared with the conventional FEA. The 3-D end effects and the effect of pulsewidth-modulation switching harmonics are incorporated in the analytical calculations. The algorithms are applied to two fractional-slot concentrated-winding interior PM motors with different circumferential and axial PM block segmentation arrangements. The method is validated against 2-D and 3-D time-stepping FEA.

Timoshenko Beam Effects In Lateral-Mode Microcantilever-Based Sensors In Liquids, Joshua A. Schultz, Stephen M. Heinrich, Fabien Josse, Nicholas J. Nigro, Isabelle Dufour, Luke A. Beardslee, Oliver Brand

Civil and Environmental Engineering Faculty Research and Publications

Recent experimental and analytical research has shown that higher in-fluid quality factors (Q) are achieved by actuating microcantilevers in the lateral flexural mode, especially for microcantilevers having larger width-to-length ratios. However, experimental results show that for these geometries the resonant characteristics predicted by the existing analytical models differ from the measurements. A recently developed analytical model to more accurately predict the resonant behaviour of these devices in viscous fluids is described. The model incorporates viscous fluid effects via a Stokes-type fluid resistance assumption and `Timoshenko beam' effects (shear deformation and rotatory inertia). Unlike predictions based on Euler-Bernoulli beam …

Conditional Spectrum-Based Ground Motion Selection. Part Ii: Intensity-Based Assessments And Evaluation Of Alternative Target Spectra, Ting Lin, Curt B. Haselton, Jack W. Baker

Civil and Environmental Engineering Faculty Research and Publications

In a companion paper, an overview and problem definition was presented for ground motion selection on the basis of the conditional spectrum (CS), to perform risk-based assessments (which estimate the annual rate of exceeding a specified structural response amplitude) for a 20-story reinforced concrete frame structure. Here, the methodology is repeated for intensity-based assessments (which estimate structural response for ground motions with a specified intensity level) to determine the effect of conditioning period. Additionally, intensity-based and risk-based assessments are evaluated for two other possible target spectra, specifically the uniform hazard spectrum (UHS) and the conditional mean spectrum (CMS, without variability).It …

Conditional Spectrum-Based Ground Motion Selection. Part I: Hazard Consistency For Risk-Based Assessments, Ting Lin, Curt B. Haselton, Jack W. Baker

Civil and Environmental Engineering Faculty Research and Publications

The conditional spectrum (CS, with mean and variability) is a target response spectrum that links nonlinear dynamic analysis back to probabilistic seismic hazard analysis for ground motion selection. The CS is computed on the basis of a specified conditioning period, whereas structures under consideration may be sensitive to response spectral amplitudes at multiple periods of excitation. Questions remain regarding the appropriate choice of conditioning period when utilizing the CS as the target spectrum. This paper focuses on risk-based assessments, which estimate the annual rate of exceeding a specified structural response amplitude. Seismic hazard analysis, ground motion selection, and nonlinear dynamic …

Microelectromechanical Systems (Mems) Resistive Heaters As Circuit Protection Devices, Ronald A. Coutu Jr., Scott A. Ostrow

Electrical and Computer Engineering Faculty Research and Publications

With increased opportunities for the exploitation (i.e., reverse engineering) of vulnerable electronic components and systems, circuit protection has become a critical issue. Circuit protection techniques are generally software-based and include cryptography (encryption/decryption), obfuscation of codes, and software guards. Examples of hardware-based circuit protection include protective coatings on integrated circuits, trusted foundries, and macro-sized components that self-destruct, thus destroying critical components. This paper is the first to investigate the use of microelectromechanical systems (MEMS) to provide hardware-based protection of critical electronic components to prevent reverse engineering or other exploitation attempts. Specifically, surface-micromachined polycrystalline silicon to be used as meandering resistive heaters …

Effect Of Tilt Sensor Versus Heel Loading On Neuroprosthesis Stimulation Reliability And Timing For Individuals Post-Stroke During Level And Non- Level Treadmill Walking, M. Barbara Silver-Thorn

Biomedical Engineering Faculty Research and Publications

Study background: Non-level walking may adversely affect stimulation of neuroprostheses as initial programming is performed during level walking. The objectives of this study were to assess stimulation reliability of tilt and heel sensor-based neuroprosthesis stimulation during level and non-level walking, examine stimulation initiation and termination timing during level and non-level walking, and determine whether heel or tilt sensor-based stimulation control is more robust for non-level ambulation. Methods: Eight post-stroke individuals with drop foot who were able to actively ambulate within the community were selected for participation. Each subject acclimated to the neuroprosthesis and walked on a treadmill randomly positioned in …

Characterization And Limitations Of Diffusion Tensor Imaging Metrics In The Cervical Spinal Cord In Neurologically Intact Subjects, Aditya Vedantam, Michael B. Jirjis, Brian D. Schmit, Marjorie C. Wang, John L. Ulmer, Shekar N. Kurpad

Biomedical Engineering Faculty Research and Publications

Purpose

To characterize diffusion tensor imaging (DTI) metrics across all levels of the cervical spinal cord (CSC) and to study the impact of age and signal quality on these metrics.

Materials and Methods

DTI metrics were calculated for gray matter (GM) and white matter (WM) funiculi throughout the CSC (C1–T1) in 25 healthy subjects (22-85 years old). Signal-to-noise ratios (SNRs) and mean DTI metrics were measured for the upper (C1-3), middle (C4-6) and lower (C7-T1) cervical segments. Age-related changes in DTI metrics were analyzed for the individual segment groups.

Results

Fractional anisotropy (FA), mean diffusivity (MD) and transverse apparent diffusion …

Industrial Symbiosis: Corn Ethanol Fermentation, Hydrothermal Carbonization, And Anaerobic Digestion, Patrick J. Mcnamara, Lindsey R. Jader, Frederick J. Schendel, Nicholas J. Hahn, Brandon M. Wood, Kenneth J. Valentas, Paige M. Novak, Steven J. Heilmann

Civil and Environmental Engineering Faculty Research and Publications

The production of dry-grind corn ethanol results in the generation of intermediate products, thin and whole stillage, which require energy-intensive downstream processing for conversion into commercial animal feed products. Hydrothermal carbonization of thin and whole stillage coupled with anaerobic digestion was investigated as alternative processing methods that could benefit the industry. By substantially eliminating evaporation of water, reductions in downstream energy consumption from 65% to 73% were achieved while generating hydrochar, fatty acids, treated process water, and biogas co-products providing new opportunities for the industry. Processing whole stillage in this manner produced the four co-products, eliminated centrifugation and evaporation, and …

Neural Dynamics Of Phonological Processing In The Dorsal Auditory Stream, Einat Liebenthal, Merav Sabri, Scott A. Beardsley, Jain Mangalathu-Arumana, Anjali Desai

Biomedical Engineering Faculty Research and Publications

Neuroanatomical models hypothesize a role for the dorsal auditory pathway in phonological processing as a feedforward efferent system (Davis and Johnsrude, 2007; Rauschecker and Scott, 2009; Hickok et al., 2011). But the functional organization of the pathway, in terms of time course of interactions between auditory, somatosensory, and motor regions, and the hemispheric lateralization pattern is largely unknown. Here, ambiguous duplex syllables, with elements presented dichotically at varying interaural asynchronies, were used to parametrically modulate phonological processing and associated neural activity in the human dorsal auditory stream. Subjects performed syllable and chirp identification tasks, while event-related potentials and …

A Review Of Micro-Contact Physics For Microelectromechanical Systems (Mems) Metal Contact Switches, Benjamin F. Toller, Ronald A. Coutu Jr., John W. Mcbride

Electrical and Computer Engineering Faculty Research and Publications

Innovations in relevant micro-contact areas are highlighted, these include, design, contact resistance modeling, contact materials, performance and reliability. For each area the basic theory and relevant innovations are explored. A brief comparison of actuation methods is provided to show why electrostatic actuation is most commonly used by radio frequency microelectromechanical systems designers. An examination of the important characteristics of the contact interface such as modeling and material choice is discussed. Micro-contact resistance models based on plastic, elastic-plastic and elastic deformations are reviewed. Much of the modeling for metal contact micro-switches centers around contact area and surface roughness. Surface roughness and …

Validation Of Earthquake Simulations And Their Effects On Tall Buildings Considering Spectral Shape And Duration, Ting Lin, Gregory Deierlein, Nenad Bijelic

Civil and Environmental Engineering Faculty Research and Publications

No abstract provided.

Automated Multi-Objective Design Optimization Of Pm Ac Machines Using Computationally Efficient Fea And Differential Evolution, Gennadi Y. Sizov, Peng Zhang, Dan M. Ionel, Nabeel Demerdash, Marius Rosu

Electrical and Computer Engineering Faculty Research and Publications

The design optimization methods described in this paper are employing an ultrafast computationally efficient finite element analysis technique. A minimum number of magnetostatic solutions are used for the analysis, which makes possible the study of thousands of candidate motor designs with typical PC-workstation computational resources. A multi-objective differential evolution algorithm that considers a large number of independent stator and rotor geometric variables and performance criteria, such as average and ripple torque, losses, and efficiency, is used. The optimization method is demonstrated on different permanent magnet (PM) ac synchronous motors in the kilowatt and megawatt power ranges. For the low-power PM …

Changes In Hemodynamic Responses In Chronic Stroke Survivors Do Not Affect Fmri Signal Detection In A Block Experimental Design, Nutta-On Promjunyakul, Brian D. Schmit, Sheila Schindler-Ivens

Physical Therapy Faculty Research and Publications

The use of canonical functions to model BOLD-fMRI data in people post-stroke may lead to inaccurate descriptions of task-related brain activity. The purpose of this study was to determine whether the spatiotemporal profile of hemodynamic responses (HDRs) obtained from stroke survivors during an event-related experiment could be used to develop individualized HDR functions that would enhance BOLD-fMRI signal detection in block experiments. Our long term goal was to use this information to develop individualized HDR functions for stroke survivors that could be used to analyze brain activity associated with locomotor-like movements. We also aimed to examine the reproducibility of HDRs …

How Industry Benefits From Student Design, Jay R. Goldberg

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Hypoxia Preconditioning Increases Survival And Decreases Expression Of Toll-Like Receptor 4 In Pulmonary Artery Endothelial Cells Exposed To Lipopolysaccharide, Irshad Ali, Rahul Nanchal, Fouad Husnain, Said H. Audi, G. Ganesh Konduri, John C. Densmore, Meetha Medhora, Elizabeth R. Jacobs

Biomedical Engineering Faculty Research and Publications

Pulmonary or systemic infections and hypoxemic respiratory failure are among the leading causes of admission to intensive care units, and these conditions frequently exist in sequence or in tandem. Inflammatory responses to infections are reproduced by lipopolysaccharide (LPS) engaging Toll-like receptor 4 (TLR4). Apoptosis is a hallmark of lung injury in sepsis. This study was conducted to determine whether preexposure to LPS or hypoxia modulated the survival of pulmonary artery endothelial cells (PAECs). We also investigated the role TLR4 receptor expression plays in apoptosis due to these conditions. Bovine PAECs were cultured in hypoxic or normoxic environments and treated with …

Ex Vivo Diffusion Tensor Imaging Of Spinal Cord Injury In Rats Of Varying Degrees Of Severity, Michael Jirjis, Shekar N. Kurpad, Brian D. Schmit

Biomedical Engineering Faculty Research and Publications

The aim of this study was to characterize magnetic resonance diffusion tensor imaging (DTI) in proximal regions of the spinal cord following a thoracic spinal cord injury (SCI). Sprague–Dawley rats (n = 40) were administered a control, mild, moderate, or severe contusion injury at the T8 vertebral level. Six direction diffusion weighted images (DWIs) were collected ex vivo along the length of the spinal cord, with an echo/repetition time of 31.6 ms/14 sec and b = 500 sec/mm2. Diffusion metrics were correlated to hindlimb motor function. Significant differences were found for whole cord region of interest (ROI) drawings for fractional …

Outer Retinal Structure In Best Vitelliform Macular Dystrophy, David B. Kay, Megan E. Land, Robert F. Cooper, Adam M. Dubis, Pooja Godara, Alfredo Dubra, Joseph Carroll, Kimberly E. Stepien

Biomedical Engineering Faculty Research and Publications

Importance Demonstrating the utility of adaptive optics scanning light ophthalmoscopy (AOSLO) to assess outer retinal structure in Best vitelliform macular dystrophy (BVMD).

Objective To characterize outer retinal structure in BVMD using spectral-domain optical coherence tomography (SD-OCT) and AOSLO.

Design, Setting, and Participants Prospective, observational case series. Four symptomatic members of a family with BVMD with known BEST1 mutation were recruited at the Advanced Ocular Imaging Program research lab at the Medical College of Wisconsin Eye Institute, Milwaukee.

Intervention Thickness of 2 outer retinal layers corresponding to photoreceptor inner and outer segments was measured using SD-OCT. Photoreceptor mosaic AOSLO images within …

Few-View Single Photon Emission Computed Tomography (Spect) Reconstruction Based On A Blurred Piecewise Constant Object Model, Paul Arthur Wolf, Jakob S. Jørgensen, Taly Gilat Schmidt, Emil Y. Sidky

Biomedical Engineering Faculty Research and Publications

A sparsity-exploiting algorithm intended for few-view single photon emission computed tomography (SPECT) reconstruction is proposed and characterized. The algorithm models the object as piecewise constant subject to a blurring operation. To validate that the algorithm closely approximates the true object in the noiseless case, projection data were generated from an object assuming this model and using the system matrix. Monte Carlo simulations were performed to provide more realistic data of a phantom with varying smoothness across the field of view and a cardiac phantom. Reconstructions were performed across a sweep of two primary design parameters. The results demonstrate that the …

Evaluation Of Cast Creep Occurring During Simulated Clubfoot Correction, Tamara L. Cohen, Haluk Altiok, Mei Wang, Linda M. Mcgrady, Joseph Krzak, Adam Graf, Sergey Tarima, Peter A. Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

The Ponseti method is a widely accepted and highly successful conservative treatment of pediatric clubfoot involving weekly manipulations and cast applications. Qualitative assessments have indicated the potential success of the technique with cast materials other than standard plaster of Paris. However, guidelines for clubfoot correction based on the mechanical response of these materials have yet to be investigated. The current study sought to characterize and compare the ability of three standard cast materials to maintain the Ponseti-corrected foot position by evaluating cast creep response. A dynamic cast testing device, built to model clubfoot correction, was wrapped in plaster of Paris, …

Young's Modulus And Volume Porosity Relationships For Additive Manufacturing Applications, M. Barbara Silver-Thorn

Biomedical Engineering Faculty Research and Publications

Recent advancements in additive manufacturing (or rapid prototyping) technologies allow the fabrication of end-use components with defined porous structures. For example, one area of particular interest is the potential to modify the flexibility (bending stiffness) of orthopedic implants through the use of engineered porosity (i.e., design and placement of pores) and subsequent fabrication of the implant using additive manufacturing processes. However, applications of engineered porosity require the ability to accurately predict mechanical properties from knowledge or characterization of the pore structure and the existence of robust equations characterizing the property–porosity relationships. As Young’s modulus can be altered by variations in …

Reducing Radiation Dose To The Female Breast During Ct Coronary Angiography: A Simulation Study Comparing Breast Shielding, Angular Tube Current Modulation, Reduced Kv, And Partial Angle Protocols Using An Unknown-Location Signal-Detectability Metric, Franco Rupcich, Andreu Badal, Lucretiu M. Popescu, Iacovos Kyprianou, Taly Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

Purpose:

The authors compared the performance of five protocols intended to reduce dose to the breast during computed tomography (CT) coronary angiography scans using a model observer unknown-location signal-detectability metric.

Methods:

The authors simulated CT images of an anthropomorphic female thorax phantom for a 120 kV reference protocol and five “dose reduction” protocols intended to reduce dose to the breast: 120 kV partial angle (posteriorly centered), 120 kV tube-current modulated (TCM), 120 kV with shielded breasts, 80 kV, and 80 kV partial angle (posteriorly centered). Two image quality tasks were investigated: the detection and localization of 4-mm, 3.25 mg/ml and …

In Vivo Imaging Of Human Retinal Microvasculature Using Adaptive Optics Scanning Light Ophthalmoscope Fluorescein Angiography, Alexander Pinhas, Michael Dubow, Nishit Shah, Toco Y.P. Chui, Drew Scoles, Yusufu N. Sulai, Rishard Weitz, Joseph B. Walsh, Joseph Carroll, Alfredo Dubra, Richard B. Rosen

Biomedical Engineering Faculty Research and Publications

The adaptive optics scanning light ophthalmoscope (AOSLO) allows visualization of microscopic structures of the human retina in vivo. In this work, we demonstrate its application in combination with oral and intravenous (IV) fluorescein angiography (FA) to the in vivo visualization of the human retinal microvasculature. Ten healthy subjects ages 20 to 38 years were imaged using oral (7 and/or 20 mg/kg) and/or IV (500 mg) fluorescein. In agreement with current literature, there were no adverse effects among the patients receiving oral fluorescein while one patient receiving IV fluorescein experienced some nausea and heaving. We determined that all retinal capillary …

Young’S Modulus And Volume Porosity Relationships For Additive Manufacturing Applications, John Anthony Choren, Stephen M. Heinrich, M. Barbara Silver-Thorn

Civil and Environmental Engineering Faculty Research and Publications

Recent advancements in additive manufacturing (or rapid prototyping) technologies allow the fabrication of end-use components with defined porous structures. For example, one area of particular interest is the potential to modify the flexibility (bending stiffness) of orthopedic implants through the use of engineered porosity (i.e., design and placement of pores) and subsequent fabrication of the implant using additive manufacturing processes. However, applications of engineered porosity require the ability to accurately predict mechanical properties from knowledge or characterization of the pore structure and the existence of robust equations characterizing the property–porosity relationships. As Young’s modulus can be altered by variations in …

An Efficient Cost Function For The Optimization Of An N-Layered Isotropic Cloaked Cylinder, Jason V. Paul, Peter J. Collins, Ronald A. Coutu Jr.

Electrical and Computer Engineering Faculty Research and Publications

In this paper, we present an efficient cost function for optimizing n-layered isotropic cloaked cylinders. Cost function efficiency is achieved by extracting the expression for the angle independent scatterer contribution of an associated Green's function. Therefore, since this cost function is not a function of angle, accounting for every bistatic angle is not necessary and thus more efficient than other cost functions. With this general and efficient cost function, isotropic cloaked cylinders can be optimized for many layers and material parameters. To demonstrate this, optimized cloaked cylinders made of 10, 20 and 30 equal thickness layers are presented for …

Rnn Language Model With Word Clustering And Class-Based Output Layer, Yongzhe Shi, Wei-Qiang Zhang, Jia Liu, Michael T. Johnson

Electrical and Computer Engineering Faculty Research and Publications

The recurrent neural network language model (RNNLM) has shown significant promise for statistical language modeling. In this work, a new class-based output layer method is introduced to further improve the RNNLM. In this method, word class information is incorporated into the output layer by utilizing the Brown clustering algorithm to estimate a class-based language model. Experimental results show that the new output layer with word clustering not only improves the convergence obviously but also reduces the perplexity and word error rate in large vocabulary continuous speech recognition.