Biomedical Engineering and Bioengineering Commons^™

In Vivo Dark-Field Imaging Of The Retinal Pigment Epithelium Cell Mosaic, Drew Scoles, Yusufu N. Sulai, Alfredo Dubra

Biomedical Engineering Faculty Research and Publications

Non-invasive reflectance imaging of the human RPE cell mosaic is demonstrated using a modified confocal adaptive optics scanning light ophthalmoscope (AOSLO). The confocal circular aperture in front of the imaging detector was replaced with a combination of a circular aperture 4 to 16 Airy disks in diameter and an opaque filament, 1 or 3 Airy disks thick. This arrangement reveals the RPE cell mosaic by dramatically attenuating the light backscattered by the photoreceptors. The RPE cell mosaic was visualized in all 7 recruited subjects at multiple retinal locations with varying degrees of contrast and cross-talk from the photoreceptors. Various experimental …

Biomechanical Modeling Of Pediatric Clubfoot, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Brittle Bone Fracture Risk With Transverse Isotropy, Jessica M. Fritz, Nicole M. Grosland, Peter A. Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Safety And Efficacy Of Ranolazine For The Treatment Of Chronic Angina Pectoris, Mohammed Aldakkak, David F. Stowe, Amadou K.S. Camara

Biomedical Engineering Faculty Research and Publications

Coronary heart disease is a global malady and it is the leading cause of death in the United States. Chronic stable angina is the most common manifestation of coronary heart disease and it results from the imbalance between myocardial oxygen supply and demand due to reduction in coronary blood flow. Therefore, in addition to lifestyle changes, commonly used pharmaceutical treatments for angina (nitrates, ß-blockers, Ca2+ channel blockers) are aimed at increasing blood flow or decreasing O2 demand. However, patients may continue to experience symptoms of angina. Ranolazine is a relatively new drug with anti-anginal and anti-arrhythmic effects. Its anti-anginal mechanism …

Bone Properties By Nanoindentation In Mild And Severe Osteogenesis Imperfecta, Carolyne Albert, John Jameson, Jeffrey M. Toth, Peter Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Background

Osteogenesis imperfecta is a heterogeneous genetic disorder characterized by bone fragility. Previous research suggests that impaired collagen network and abnormal mineralization affect bone tissue properties, however, little data is yet available to describe bone material properties in individuals with this disorder. Bone material properties have not been characterized in individuals with the most common form of osteogenesis imperfecta, type I.

Methods

Bone tissue elastic modulus and hardness were measured by nanoindentation in eleven osteotomy specimens that were harvested from children with osteogenesis imperfecta during routine surgeries. These properties were compared between osteogenesis imperfecta types I (mild, n = …

Biplane Fluoroscopic Analysis Of The Hindfoot Using Model-Based Tracking Techniques: A Static Phantom Study, Janelle A. Cross, Ben Mchenry, Gerald F. Harris, Taly Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

No abstract provided.

3d Visualization Of Reference-Point Indentation In Human And Murine Bone, John Jameson, Alex Proctor, Carolyne Albert, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Markerless Analysis Of Upper Extremity Kinematics During Standardized Pediatric Functional Assessment With A Low-Cost Motion Analysis System, Gerald F. Harris, Susan A. Riedel

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Improving Brain–Machine Interface Performance By Decoding Intended Future Movements, Francis R. Willett, Aaron J. Suminski, Andrew H. Fagg, Nicholas G. Hatsopoulos

Biomedical Engineering Faculty Research and Publications

Objective. A brain–machine interface (BMI) records neural signals in real time from a subject's brain, interprets them as motor commands, and reroutes them to a device such as a robotic arm, so as to restore lost motor function. Our objective here is to improve BMI performance by minimizing the deleterious effects of delay in the BMI control loop. We mitigate the effects of delay by decoding the subject's intended movements a short time lead in the future. Approach. We use the decoded, intended future movements of the subject as the control signal that drives the movement of our BMI. This …

Experimental Study Of Optimal Energy Weighting In Energy-Resolved Ct Using A Czt Detector, Franco Rupcich, Taly Gilat-Schmidt

Biomedical Engineering Faculty Research and Publications

Recent advances in energy-resolved CT can potentially improve contrast-to-noise ratio (CNR), which could subsequently reduce dose in conventional and dedicated breast CT. Two methods have been proposed for optimal energy weighting: weighting the energy-bin data prior to log normalization (projection-based weighting) and weighting the energy-bin data after log normalization (image-based weighting). Previous studies suggested that optimal projection-based and image-based energy weighting provide similar CNR improvements for energy-resolved CT compared to photon-counting or conventional energy-integrating CT. This study experimentally investigated the improvement in CNR of projection-based and image-based weighted images relative to photon-counting for six different energy-bin combinations using a bench …

Visuomotor Learning Enhanced By Augmenting Instantaneous Trajectory Error Feedback During Reaching, James L. Patton, John Wei Yejun, Preeti Bajaj, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

We studied reach adaptation to a 30u visuomotor rotation to determine whether augmented error feedback can promote faster and more complete motor learning. Four groups of healthy adults reached with their unseen arm to visual targets surrounding a central starting point. A manipulandum tracked hand motion and projected a cursor onto a display immediately above the horizontal plane of movement. For one group, deviations from the ideal movement were amplified with a gain of 2 whereas another group experienced a gain of 3.1. The third group experienced an offset equal to the average error seen in the initial perturbations, while …

Comparison Of Randomized Multifocal Mapping And Temporal Phase Mapping Of Visual Cortex For Clinical Use, Yan Ma, B. Douglas Ward, Kristina M. Ropella, Edgar A. Deyoe

Biomedical Engineering Faculty Research and Publications

fMRI is becoming an important clinical tool for planning and guidance of surgery to treat brain tumors, arteriovenous malformations, and epileptic foci. For visual cortex mapping, the most popular paradigm by far is temporal phase mapping, although random multifocal stimulation paradigms have drawn increased attention due to their ability to identify complex response fields and their random properties. In this study we directly compared temporal phase and multifocal vision mapping paradigms with respect to clinically relevant factors including: time efficiency, mapping completeness, and the effects of noise. Randomized, multifocal mapping accurately decomposed the response of single voxels to multiple stimulus …

A Hands-On, Active Learning Approach To Increasing Manufacturing Knowledge In Engineering Students, Jay R. Goldberg, David B. Rank

Biomedical Engineering Faculty Research and Publications

This paper describes a new learning module implemented as part of the senior capstone design course at Marquette University to teach engineering students about basic manufacturing processes, lean manufacturing principles, and design for manufacturability. The module includes several examples of active and student centered learning as part of an in-class assembly line simulation exercise. Students reflected on this experience, and suggested process improvements to save time, reduce cost and waste, and improve the assembly line process. They learned of the importance of manufacturing documentation, process design, and design for assembly. At the end of the module, students understood the importance …

Theranostic Oxygen Delivery Using Ultrasound And Microbubbles, James J. Kwan, Mehmet Kaya, Mark A. Borden, Paul A. Dayton

Biomedical Engineering and Sciences Faculty Publications

Means to overcome tumor hypoxia have been the subject of clinical investigations since the 1960’s; however these studies have yet to find a treatment which is widely accepted. It has been known for nearly a century that hypoxic cells are more resistant to radiotherapy than aerobic cells, and tumor hypoxia is a major factor leading to the resistance of tumors to radiation treatment as well as several cytotoxic agents. In this manuscript, the application of ultrasound combined with oxygen-carrier microbubbles is demonstrated as a method to locally increase dissolved oxygen. Microbubbles can also be imaged by ultrasound, thus providing the …

Comparison Of 4d Phase-Contrast Mri Flow Measurements To Computational Fluid Dynamics Simulations Of Cerebrospinal Fluid Motion In The Cervical Spine, Theresia Yiallourou, Jan Robert Kroger, Nikolaos Stergiopulos, David Maintz, Bryn A. Martin, Alexander C. Bunck

Mechanical Engineering Faculty Research

Cerebrospinal fluid (CSF) dynamics in the cervical spinal subarachnoid space (SSS) have been thought to be important to help diagnose and assess craniospinal disorders such as Chiari I malformation (CM). In this study we obtained time-resolved three directional velocity encoded phase-contrast MRI (4D PC MRI) in three healthy volunteers and four CM patients and compared the 4D PC MRI measurements to subject-specific 3D computational fluid dynamics (CFD) simulations. The CFD simulations considered the geometry to be rigid-walled and did not include small anatomical structures such as nerve roots, denticulate ligaments and arachnoid trabeculae. Results were compared at nine axial planes …

A Depolymerization Based Model Of Neuron Growth Cone Shape And Motility, Neerajha Nagarajan

Master's Theses

Cell migration is a ubiquitous process underlying critical biological mechanisms like wound healing, cancer metastasis and even neuron growth cone motility. It is a critical process for the living organisms as it ensures proper functioning of the system, for example, crawling fibroblasts endure closure of wounds during wound healing. Here we focus our interest on neuron growth cones, a sensory and motile organelle present at the tip of extending neurites, like the axons, in neurons. These are responsible for neuron pathfinding onto specific targets and synapses, in responses to various guidance cues. Interestingly, the motility of the growth cones is …

Plantar Measurements To Determine Success Of Surgical Correction Of Stage Iib Adult Acquired Flatfoot Deformity, Erika Matheis

Theses and Dissertations

Adult Acquired Flatfoot Deformity (AAFD) is a progressive disease characterized by mechanical degeneration of the soft tissue structure in the arch of the foot that leads to changes in joint alignment. Surgical intervention commonly via tendon transfer and bony osteotomy is used to restore arch architecture, however there is a lack of quantitative assessments that measure the success of the surgical correction in vivo. Using plantar pressures via Tekscan® HR Mat and surveys (SF-36, FAOS), pre-operative and post-operative measures for six participants were defined, analyzed and compared. A paired t-test showed significant lateral shift for percent body weight during walking …

Role Of Epidermal Growth Factor-Triggered Pi3k/Akt Signaling In The Migration Of Medulloblastoma-Derived Cells, Veronica Dudu, Richard A. Able, Jr., Veronica Rotari, Qingjun Kong, Maribel Vazquez

Publications and Research

Medulloblastoma (MB) is the most common brain cancer diagnosed among children. The cellular pathways that regulate MB invasion in response to environmental cues remain incompletely understood. Herein, we examine the migratory response of human MB-derived Daoy cells to different concentration profiles of Epidermal Growth Factor (EGF) using a microfluidic system. Our findings provide the first quantitative evidence that EGF concentration gradients modulate the chemotaxis of MB-derived cells in a dose-dependent manner via the EGF receptor (EGF-R). Data illustrates that higher concentration gradients caused increased number of cells to migrate. In addition, our results show that EGF-induced receptor phosphorylation triggered the …

Voltage Effects On Cells Cultured On Metallic Biomedical Implants, Seyed Morteza Haerihosseini

Biomedical and Chemical Engineering - Dissertations

Electrochemical voltage shifts in metallic biomedical implants occur in-vivo due to a number of processes including mechanically assisted corrosion. Surface potential of biomedical implants and excursions from resting open circuit potential (OCP), which is the voltage they attain while in contact with an electrolyte, can significantly change the interfacial properties of the metallic surfaces and alter the behavior of the surrounding cells, compromising the biocompatibility of metallic implants. Voltages can also be controlled to modulate cell function and fate. To date, the details of the physico-chemical phenomena and the role of different biomaterial parameters involved in the interaction between cells …

Reducing In-Stent Restenosis Through Novel Stent Flow Field Augmentation, Eoin Murphy, Fergal Boyle

Articles

In-stent restenosis (ISR), manifested as a re-narrowing of the arterial lumen post-implantation of a stent, is a detrimental limitation of stent technology. Understanding and consequently devising ways of reducing the frequency of ISR has been a continuing goal of research into improved stent designs. The biological processes that can lead to ISR have been found to be partially flow dependent with the local hemodynamics at the arterial wall of crucial importance. This paper investigates these biological processes and their instigating factors. Furthermore, the history and theory behind three stent technologies which endeavour to reduce ISR rates through stent flow field …