Engineering Commons^™

Mechanism Of Preconditioning By Isoflurane In Rabbits: A Direct Role For Reactive Oxygen Species, Katsuya Tanaka, Dorothee Weihrauch, Franz Kehl, Lynda M. Ludwig, John F. Ladisa, Judy R. Kersten, Paul S. Pagel, David C. Warltier

Biomedical Engineering Faculty Research and Publications

LARGE quantities of reactive oxygen species (ROS) released during reperfusion after coronary artery occlusion damage proteins responsible for intracellular homeostasis, produce tissue injury, depress contractile function, and increase myocardial infarct size. In contrast, small quantities of ROS may exert beneficial effects during ischemia and reperfusion when released before a prolonged ischemic event. ROS derived from mitochondria during a brief ischemic episode produce preconditioning. Free radical scavengers administered during ischemic preconditioning (IPC) markedly attenuate the protective effect of the preconditioning stimulus on infarct size. These data suggest that IPC is mediated in part by small quantities of ROS released during preconditioning. …

Comprehensive Subgrade Deflection Acceptance Criteria - Executive Summary, James Crovetti

Transportation Research Center: Subgrade Deflection Studies

This executive summary presents a summary of the findings of all study phases conducted to develop recommendations for the development of specifications for subgrade acceptance based on measured deflections. The rolling wheel deflectomter (RWD), portable truck-mounted deflection measurement systems, and dynamic cone penetrometer (DCP) were utilized on numerous subgrade construction projects between the 1998 and 2001 construction seasons. Comparative nuclear density and soil stiffness gauge readings were also obtained at selected locations on many of the included construction projects.

The research findings indicate that deflection test results may be appropriate for identifying areas of poor in-place stability within constructed subgrades. …

A Rehabilitation Engineering Course For Biomedical Engineers, M. Barbara Silver-Thorn

Biomedical Engineering Faculty Research and Publications

This paper describes an upper division elective course in rehabilitation engineering that addresses prosthetics and orthotics, wheelchair design, seating and positioning, and automobile modifications for individuals with disabilities. Faculty lectures are enhanced by guest lectures and class field trips. Guest lecturers include a prosthetist and a lower extremity amputee client, an engineer/prosthetist specializing in the upper extremity, and a rehabilitation engineer. The lower extremity prosthetist and his client present a case study for prosthetic prescription, fabrication, fitting, alignment, and evaluation. The engineer/prosthetist contrasts body-powered versus externally powered upper extremity prostheses and associated design, fitting, and functional considerations; he also discusses …

Evaluation Of 70/30 D,L-Pla For Use As A Resorbable Interbody Fusion Cage, Jeffrey M. Toth, Mei Wang, Jeffrey L. Scifert, G. Bryan Cornwall, Bradley T. Estes, Howard Seim, Simon Turner

Biomedical Engineering Faculty Research and Publications

Titanium lumbar interbody spinal fusion devices are reported to be 90% effective for single-level lumbar interbody fusion, although radiographic determination of fusion has been debated. Using blinded radiographic, biomechanic, histologic, and statistical measures, researchers in the present study evaluated a radiolucent 70/30 poly(L-lactide-co-D,L-lactide) (70/30 D,L-PLa) interbody fusion device packed with autograft or rhBMP-2 on a collagen sponge in 25 sheep at 3, 6, 12, 18, and 24 months. A trend of increased fusion stiffness, radiographic fusion, and histologic fusion was demonstrated from 3 months to 24 months. Device degradation was associated with a mild to moderate chronic inflammatory response at …

An Automated Coronary Artery Occlusion Device For Stimulating Collateral Development In Vivo, Richard Rys, John F. Ladisa, John P. Tessmer, Weidong Gu, Judy R. Kersten, David C. Warltier, Paul S. Pagel

Biomedical Engineering Faculty Research and Publications

Introduction: Repetitive, brief coronary artery occlusions produce collateral development in experimental animals. This model causes coronary collateralization in a highly reproducible fashion, but the process is very labor intensive. We report the design and use of a fully automated hydraulic coronary occlusion device capable of producing repetitive coronary occlusions and enhancement of coronary collateral development in dogs.

Methods: The device consists of analog electronics that allow adjustment of occlusion number, frequency, pressure and duration, and mechanical components responsible for the coronary occlusion. The motor and piston of the device are coupled to a chronically implanted hydraulic vascular occluder …

Investigation Of Lower-Limb Tissue Perfusion During Loading, Barbara Silver-Thorn

Biomedical Engineering Faculty Research and Publications

An extant tissue indentor used for amputee residual limb tissue indentation studies was modified to include laser Doppler flowmetry (LDF) to enable measurement of tissue perfusion during indentation. This device allows quantitative assessment of the mechanical and physiological response of soft tissues to load, as demonstrated by indentation studies of the lower-limb tissues of young healthy subjects. Potential measures of interest include the relative change in tissue perfusion with load and the time delays associated with the perfusion response during tissue loading and unloading. Such measures may prove useful in future studies of residual limb tissues, improving our understanding of …

Transfer Length Of Strands In Prestressed Concrete Piles, Baolin Wan, Kent A. Harries, Michael F. Petrou

Civil and Environmental Engineering Faculty Research and Publications

A top bar effect has been identified in prestressed concrete piles. The effect that this top bar effect has on the development of the prestressing strand is investigated. Strand transfer length is found to be proportional to the observed end slip. While the average transfer length of all strands in a section may satisfy the assumptions inherent in the ACI transfer length equation, due to the top bar effect, top-cast strand transfer lengths are considerably in excess of the ACI-calculated value. The flexural behavior of the pile, accounting for varying transfer lengths through its section, is investigated. Finally, recommendations for …

Sufficient Conditions Used In Admittance Selection For Planar Force-Guided Assembly, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

Admittance control approaches show significant promise in providing reliable force-guided assembly. An important issue in the development of these approaches is the specification of an appropriate admittance control law. This paper identifies procedures for selecting the appropriate admittance to achieve reliable planar force-guided assembly for single-point contact cases. A set of conditions that are imposed on the admittance matrix is presented. These conditions ensure that the motion that results from contact reduces part misalignment. We show that for bounded misalignment, if the conditions are satisfied for a finite number of contact configurations, the system ensures that force guidance is achieved …

Point Of View: Artificial Intervertebral Disc Replacement Using Bioactive Three-Dimensional Fabric, Jeffrey M. Toth

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Histologic Evaluation Of The Efficacy Of Rhbmp-2 Compared With Autograft Bone In Sheep Spinal Anterior Interbody Fusion, Harvinder Sandhu, Jeffrey M. Toth, Ashish Diwan, H. B. Seim Iii, Linda E.A. Kanim, J. Michael Kabo, A. Simon Turner

Biomedical Engineering Faculty Research and Publications

Study Design. The sheep anterior lumbar spinal fusion model was used to study the efficacy of recombinant human bone morphogenetic protein-2 (rhBMP-2)–collagen composite in comparison with autograft to enhance spinal interbody fusion. Comparisons were drawn from temporal radiographic and end-point biomechanical and histologic data.

Objective. To analyze histologically the ability of rhBMP-2 to achieve complete arthrodesis between vertebral bodies.

Summary of Background Data. Studies using rhBMP for enhancement of anterior interbody fusion have used numerous endpoints. However, systematic histologic evaluation of the fusion has not been conducted.

Methods. Twelve sheep underwent single-level anterior lumbar interbody fusion performed with a cylindrical …

Diagnostics Of Bar And End-Ring Connector Breakage Faults In Polyphase Induction Motors Through A Novel Dual Track Of Time-Series Data Mining And Time-Stepping Coupled Fe-State Space Modeling, Richard J. Povinelli, John F. Bangura, Nabeel Demerdash, Ronald H. Brown

Electrical and Computer Engineering Faculty Research and Publications

This paper develops the fundamental foundations of a technique for detection of faults in induction motors that is not based on the traditional Fourier transform frequency domain approach. The technique can extensively and economically characterize and predict faults from the induction machine adjustable speed drive design data. This is done through the development of dual-track proof-of-principle studies of fault simulation and identification. These studies are performed using our proven Time Stepping Coupled Finite Element-State Space method to generate fault case data. Then, the fault cases are classified by their inherent characteristics, so-called “signatures” or “fingerprints.” These fault signatures are extracted …

A Simple Dynamics Experiment Based On Acoustic Emission, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

This paper describes a simple experiment well suited for an undergraduate course in mechanical measurements and/or dynamics, in which physical information is extracted from an acoustic emission signature. In the experiment, a ping–pong ball is dropped onto a hard table surface and the audio signal resulting from the ball–table impacts is recorded. The times between successive bounces, or “flight times”, are used to determine the height of the initial drop and the coefficient of restitution of the impact. The experiment prompts questions about modeling the dynamics of a simple impact problem, including the use of the coefficient of restitution and …

Top Bar Effects In Prestressed Concrete Piles, Baolin Wan, Michael F. Petrou, Kent A. Harries, Aly A. Hussein

Civil and Environmental Engineering Faculty Research and Publications

The top bar effect in reinforced concrete is a widely recognized phenomenon. Currently, the ACI Building Code prescribes a 30% increase in the development length of top cast reinforcing bars. No such provision is required for strands in prestressed concrete members. In this paper, the top bar effect for prestressing strands is introduced. Parameters affecting top bar phenomena in prestressed concrete piles are identified, and strategies for reducing this effect are presented. Finally, for the first time, the application of a top bar effect factor for prestressed concrete development length calculations, similar to the one applied in reinforced concrete structural …

Estimation Of Pulmonary Arterial Volume Changes In The Normal And Hypertensive Fawn-Hooded Rat From 3d Micro-Ct Data, Robert C. Molthen, Christian Wieholt, Steven Thomas Haworth, Christopher A. Dawson

Biomedical Engineering Faculty Research and Publications

In the study of pulmonary vascular remodeling, much can be learned from observing the morphological changes undergone in the pulmonary arteries of the rat lung when exposed to chronic hypoxia or other challenges which elicit a remodeling response. Remodeling effects include thickening of vessel walls, and loss of wall compliance. Morphometric data can be used to localize the hemodynamic and functional consequences. We developed a CT imaging method for measuring the pulmonary arterial tree over a range of pressures in rat lungs. X-ray micro-focal isotropic volumetric imaging of the arterial tree in the intact rat lung provides detailed information on …

Boundary Effects On Multiplication Noise In Thin Heterostructure Avalanche Photodiodes: Theory And Experiment [Al/Sub 0.6/Ga/Sub 0.4/As/Gaas], Majeed M. Hayat, Oh-Hyun Kwon, Shuling Wang, Joe C. Campbell, Bahaa E.A. Saleh, Malvin Carl Teich

Electrical and Computer Engineering Faculty Research and Publications

The history-dependent recurrence theory for multiplication noise in avalanche photodiodes (APDs), developed by Hayat et al., is generalized to include inter-layer boundary effects in heterostructure APDs with multilayer multiplication regions. These boundary effects include the initial energy of injected carriers as well as bandgap-transition effects within a multilayer multiplication region. It is shown that the excess noise factor can be significantly reduced if the avalanche process is initiated with an energetic carrier, in which case the initial energy serves to reduce the initial dead space associated with the injected carrier. An excess noise factor reduction up to 40% below the …

Gain-Bandwidth Characteristics Of Thin Avalanche Photodiodes, Majeed M. Hayat, Oh-Hyun Kwon, Yi Pan, Paul P. Sotirelis, Joe C. Campbell, Bahaa E.A. Saleh, Malvin Carl Teich

Electrical and Computer Engineering Faculty Research and Publications

The frequency-response characteristics of avalanche photodiodes (APDs) with thin multiplication layers are investigated by means of a recurrence technique that incorporates the history dependence of ionization coefficients. In addition, to characterize the autocorrelation function of the impulse response, new recurrence equations are derived and solved using a parallel computer. The mean frequency response and the gain-bandwidth product are computed and a simple model for the dependence of the gain-bandwidth product on the multiplication-layer width is set forth for GaAs, InP, Al/sub 0.2/Ga/sub 0.8/As, and In/sub 0.52/Al/sub 0.48/As APDs. It is shown that the dead-space effect leads to a reduction (up …

Comprehensive Subgrade Deflection Acceptance Criteria - Pilot Implementation Report, James Crovetti, Jay Schabelski

Transportation Research Center: Subgrade Deflection Studies

This report has presents the findings of implementations of pilot specifications for subgrade acceptance based on measured deflections. The reconfigured rolling wheel deflectomter (RWD), portable truck-mounted deflection measurement systems, and dynamic cone penetrometer (DCP) were utilized on four subgrade construction projects during the 2001 construction season. Comparative nuclear density readings were obtained at selected locations within each project. Comparative soil stiffness gauge readings were also obtained on 2 of the pilot projects

The research findings from this and previous study phases indicate that deflection test results may be appropriate for identifying areas of poor in-place stability within constructed subgrades. However, …

Maximum-Likelihood Image Estimation Using Photon-Correlated Beams, Majeed M. Hayat, Muhammad Sajjad Abdullah, Adel Joobeur, Bahaa E.A. Saleh

Electrical and Computer Engineering Faculty Research and Publications

A theory is presented addressing the fundamental limits of image estimation in a setup that uses two photon-correlated beams. These beams have the property that their photon arrivals, as a point process, are ideally synchronized in time and space. The true image represents the spatial distribution of the optical transmittance (or reflectance) of an object. In this setup, one beam is used to probe the image while the other is used as a reference providing additional information on the actual number of photons impinging on the object. This additional information is exploited to reduce the effect of quantum noise associated …

A Pneumatically Actuated Manipulandum For Neuromotor Control Research, Aaron J Suminski, Kristina M. Ropella, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Functional magnetic resonance imaging (fMRI) techniques have great potential for identifying which neural structures are involved in the control of goal-directed reaching movements. However, fMRI techniques alone are not capable of probing the neural mechanisms involved in acquisition of novel motor behaviors because such studies require that the moving limb be perturbed in a controlled fashion. We outline a plan to design and develop a non-metallic, pneumatically actuated tool that, along with systems identification techniques and functional magnetic resonance imaging (fMRI), will characterize and quantify how the human central nervous system uses sensory information during practice-based motor learning.

Reengineering Biomedical Engineering Curricula: A New Product Development Approach, Robert A. Scheidt, L. Waples, Kristina M. Ropella

Biomedical Engineering Faculty Research and Publications

Product development engineers in medical industries have created design control procedures to ensure high quality designs that are as error-free as possible. The reason is simple; companies must adhere to certain engineering and manufacturing "best practices" in order to obtain certification of their devices for sale in the US and abroad. We describe here an ongoing effort to apply these industrial "best practices" to the design and implementation of a novel sequence of undergraduate biomedical computing courses within the Department of Bio-medical Engineering at Marquette University (Milwaukee, Wisconsin). We have tightly integrated our industrial advisory board into this design and …

Quasi-Exact Helical Cone Beam Reconstruction For Micro Ct, Jicun Hu, Robert C. Molthen, Roger Johnson, Steven Haworth, Christopher Dawson

Biomedical Engineering Faculty Research and Publications

A cone beam micro-CT system is set up to collect truncated helical cone beam data. This system includes a micro-focal X-ray source, a precision computer-controlled X-Y-Z-theta stage, and an image-intensifier coupled to a large format CCD detector. The helical scanning mode is implemented by rotating and translating the stage while keeping X-ray source and detector stationary. A chunk of bone and a mouse leg are scanned and quasi-exact reconstruction is performed using the approach proposed in J. Hu et al. (2001). This approach introduced the original idea of accessory paths with upper and lower virtual detectors having infinite axial extent. …

Public Perceptions Of The Midwest’S Pavements: Policies And Thresholds, David Kuemmel, Richard Robinson, Ronald C. Sonntag, Robert Griffin, James K. Giese

Marketing Faculty Research and Publications

A 5-year, pooled fund study with the Iowa, Minnesota, and Wisconsin departments of transportation assessed the public's perceptions of pavement improvement strategies and developed thresholds of satisfaction using the departments' physical indices, such as pavement ride and condition on rural, two-lane highways in the states. Approximately 3,600 drivers in the three states were involved in the three phases of the project, which included 18 focus groups, 400 statewide surveys in each state, and 2,300 targeted surveys across the three states. A multidisciplinary team from Marquette University and a mass media survey lab conducted the studies. A summary of focus group …