Engineering Commons^™

Quantification Of Thoracic Aorta Blood Flow By Magnetic Resonance Imaging During Supine Cycling Exercise Of Increasing Intensity, Laura M. Ellwein, John F. Ladisa, Stacy Leibham, Sheila M. Schindler-Ivens, Margaret M. Samyn

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Correct Spectral Conversion Between Surface‐Enhanced Raman And Plasmon Resonance Scattering From Nanoparticle Dimers For Single‐Molecule Detection, Kyuwan Lee

Kyuwan Lee

Simultaneous measurement of surface-enhanced Raman scattering (SERS) and localized surface plasmon resonance (LSPR) in nanoparticle dimers presents outstanding opportunities in molecular identification and in the elucidation of physical properties, such as the size, distance, and deformation of target species. SERS–LSPR instrumentation exists and has been used under limited conditions, but the extraction of SERS and LSPR readouts from a single measurement is still a challenge. Herein, the extraction of LSPR spectra from SERS signals is reported and a tool for measuring the interparticle distance from Raman enhancement data by the standardization of the SERS signal is proposed. The SERS nanoruler …

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 …

Mechanical Properties And Tensile Failure Analysis Of Novel Bio-Absorbable Mg-Zn-Cu And Mg-Zn-Se Alloys For Endovascular Applications, Dharam Persaud, Noah Budiansky, Anthony J. Mcgoron

Department of Biomedical Engineering Faculty Publications

In this paper, the mechanical properties and tensile failure mechanism of two novel bio-absorbable as-cast Mg-Zn-Se and Mg-Zn-Cu alloys for endovascular medical applications are characterized. Alloys were manufactured using an ARC melting process and tested as-cast with compositions of Mg-Zn-Se and Mg-Zn-Cu, being 98/1/1 wt.% respectively. Nanoindentation testing conducted at room temperature was used to characterize the elastic modulus (E) and surface hardness (H) for both the bare alloys and the air formed oxide layer. As compared to currently available shape memory alloys and degradable as-cast alloys, these experimental alloys possess superior as-cast mechanical properties that can increase their biocompatibility, …

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 …

Automatic Assessment Of Cardiac Left Ventricular Function Via Magnetic Resonance Images, Mariam Afshin

Electronic Thesis and Dissertation Repository

Automating global and segmental (regional) assessments of cardiac Left Ventricle (LV) function in Magnetic Resonance Images (MRI) has recently sparked an impressive research effort, which has resulted a number of techniques delivering promising performances. However, despite such an effort, the problem is still acknowledged to be challenging, with substantial room for improvements in regard to accuracy. Furthermore, most of the existing techniques are labour intensive, requiring delineations of the endo- and/or epi-cardial boundaries in all frames of a cardiac sequence.

On the one hand, global assessments of LV function focus on estimation of the Ejection Fraction (EF), which quantifies how …

Properties And Applications Of Sensory Outcome Measures In Carpal Tunnel Syndrome, Derek Km Cheung

Electronic Thesis and Dissertation Repository

This thesis aimed to determine the psychometric properties and applications of sensory threshold tools and outcome measures in patients with Carpal Tunnel Syndrome (CTS). The first chapter is a psychometric study that defines clinically important difference (CID), construct validity and responsiveness of touch and vibration threshold tools and in the Symptoms Severity Scale (SSS). The study found the CID for the PSSD and for the SSS was 0.15g/mm² and 0.50 respectively. The study also found that the Vibrometer was more representative of hand function and responsive compared PSSD. The second objective of this thesis was to determine the feasibility …

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 …

Optimal Inertial Sensor Placement And Motion Detection For Epileptic Seizure Patient Monitoring, Babak Kamalizonouzi

Electronic Thesis and Dissertation Repository

Use of inertial sensory systems to monitor and detect seizure episodes in patients suffering from epilepsy is investigated via numerical simulations and experiments. Numerical simulations employ a mathematical model that is able to predict human body dynamic responses during a typical epileptic seizure. An optimized inertial sensor placement procedure is developed to address achievement of highest possible sensing resolution in determining angular accelerations with minimal errors. In addition, a joint torque estimation procedure is formulated to assist in the future development of a possible detection scheme. Experimental motion data obtained from an epileptic seizure patient as well as a healthy …

Impact Of Bioparticle Recirculation In A Circulating Fluidized Bed Biofilm Reactor On Simultaneous Organic And Nitrogen Removal, Ming Li

Electronic Thesis and Dissertation Repository

The Circulating Fluidized Bed Biofilm Reactor (CFBBR), a bioparticle technology designed for biological nutrient removal, has been implemented to achieve considerable biodegradation efficiency and low sludge production, compared with activated sludge system and typical biofilm technology. The inherent advantages of bioparticle technology are enhanced substantially by the CFBBR, for example, decoupling of hydraulic retention time (HRT) from solids retention time (SRT), large specific surface area, ideal conditions for biofilm ecosystem.

In this work, bioparticle recirculation, as a novel control method for bioparticle system, was demonstrated in CFBBRs. To verify the impact of bioparticle recirculation on the reactor performance, bio-kinetics and …

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 …

Nanomechanics Of Electrospun Nanofibres For Tissue Engineering Of The Tympanic Membrane, Sara Makaremi

Electronic Thesis and Dissertation Repository

The Tympanic Membrane (TM), also known as the eardrum, includes layers of organized collagen nanofibres which play an essential role in sound transmission. Perforations that are caused by infection or accident must be repaired in order to restore hearing. Tympanoplasty is performed using grafts that are prepared from bladder, cartilage, temporal fascia and cadaveric skin. However, since mechanical properties of these grafts do not match those of the original TM, normal hearing is not fully restored. The goal of this study is to develop nanofibrous scaffolds for tissue engineering of the TM in order to circumvent the complications addressed with …

Investigating The Therapeutic Potential Of Salivary Proteins For Oral Diseases, Dusa Vukosavljevic

Electronic Thesis and Dissertation Repository

ABSTRACT

Saliva is responsible for the formation of the acquired enamel pellicle (AEP), a protein

integument formed as a result of selective adsorption of salivary proteins to the enamel

surface. The AEP demonstrates an important role for modulating dental erosion as a

result of its physical properties, along with its salivary and exogenous protein

composition (Chapter 2). In addition, individual proteins that comprise the AEP have

important physiological functions. Histatin 5 (H5) has potent antifungal effect against C.

albicans, the yeast responsible for the initiation of oral candidiasis. We designed an in

vitro model and found, for the first time, …

Computer Modeling And Signal Analysis Of Cardiovascular Physiology, Henian Xia

Doctoral Dissertations

This dissertation aims to study cardiovascular physiology from the cellular level to the whole heart level to the body level using numerical approaches.

A mathematical model was developed to describe electromechanical interaction in the heart. The model integrates cardio-electrophysiology and cardiac mechanics through excitation-induced contraction and deformation-induced currents. A finite element based parallel simulation scheme was developed to investigate coupled electrical and mechanical functions. The developed model and numerical scheme were utilized to study cardiovascular dynamics at cellular, tissue and organ levels. The influence of ion channel blockade on cardiac alternans was investigated. It was found that the channel blocker …

Quaternionic Attitude Estimation With Inertial Measuring Unit For Robotic And Human Body Motion Tracking Using Sequential Monte Carlo Methods With Hyper-Dimensional Spherical Distributions, Gary To

Doctoral Dissertations

This dissertation examined the inertial tracking technology for robotics and human tracking applications. This is a multi-discipline research that builds on the embedded system engineering, Bayesian estimation theory, software engineering, directional statistics, and biomedical engineering.

A discussion of the orientation tracking representations and fundamentals of attitude estimation are presented briefly to outline the some of the issues in each approach. In addition, a discussion regarding to inertial tracking sensors gives an insight to the basic science and limitations in each of the sensing components.

An initial experiment was conducted with existing inertial tracker to study the feasibility of using this …

Handitrike - Recumbent Tricycle, Sean Higginson, Kevin Howie, Vinay Patel

Mechanical Engineering

This report covers the design and construction of the recumbent racing tricycle for Mr. Robert T. Kelly, a disabled veteran. Unfortunately Rob’s right leg is five inches shorter than his left one and therefore is unable to properly operate standard cranks. Our team HandiTrike is composed of Sean Higginson, Kevin Howie, and Vinay Patel and our project requires us to come up with a design that is feasible to complete within the given three quarters, as well as allow Rob to gain full use of his tricycle. Currently Rob ‘s trike uses the standard crank set up found on most …

خلاصه روابط و معادلات

Dr Alireza Zolfaghari

No abstract provided.

My Lecture Notes (Power Plant Engineering) - Chapter 4, Dr Alireza Zolfaghari

Dr Alireza Zolfaghari

No abstract provided.

Characterization Of Polyacrylonitrile Carbon Fibers, Christian Burke Iversen

Biomedical and Chemical Engineering – Theses

Carbon fiber composites are a widely used, advanced material with exceedingly high strength to weight properties. In this thesis, a literature overview of carbon fiber manufacturing was provided, as well as a thorough analysis of in- house electrospun polyacrylonitrile fiber stabilization and surface modification of the resulting carbon fibers. In the first section, an overview of precursor fiber fabrication is provided, followed by an analysis of stabilization using surface and bulk composition, dimensional analysis, and functional group analysis via FTIR. The second section uses the current stabilization procedure to develop carbon nanofibers. Fibers first underwent a nitric acid oxidation time …

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 …

Induced Elastic Matrix Synthesis Within 3-Dimensional Collagen Constructs, Lavanya Venkataraman

All Dissertations

Elastin, a primary component of elastic arteries, maintains structural stability of the cyclically recoiling artery, and critically regulates vascular cell behavior. Accelerated degradation of elastic matrix, such as that seen in vascular pathologies like abdominal aortic aneurysms (AAA), can therefore severely compromise vessel homeostasis. Tissue engineering and in-situ matrix repair strategies evaluated so far are primarily limited in inducing adult vascular cells to replicate the complex elastic matrix assembly process, and restore lost matrix integrity. Previously, our lab established the elastogenic benefits of concurrent delivery of TGF-β1 and HA-oligomers (together termed elastogenic factors, EFs), within 2D cultures of rat aortic …

Dc And Microwave Analysis Of Gallium Arsenide Field-Effect Transistor-Based Nucleic Acid Biosensors, John K. Kimani

Theses and Dissertations

Sensitive high-frequency microwave devices hold great promise for biosensor design. These devices include GaAs field effect transistors (FETs), which can serve as transducers for biochemical reactions, providing a platform for label-free biosensing. In this study, a two-dimensional numerical model of a GaAs FET-based nucleic acid biosensor is proposed and simulated. The electronic band structure, space charge density, and current-voltage relationships of the biosensor device are calculated. The intrinsic small signal parameters for the device are derived from simulated DC characteristics and used to predict AC behavior at high frequencies.

The biosensor model is based on GaAs field-effect device physics, semiconductor …

Development Of Simulation Platform For Oropharyngeal Airway Placement And Design Evaluation Of The Bardo Airway, Lewis On Hang Lee

Master's Theses

Off-label use of traditional Oropharyngeal Airway (OPA) as a bite-block, and the subsequential procedure of force exertion of the device by physician has caused many cases of patient’s teeth damage and monetary loss, as the patient’s incisors were damaged while clenching on the OPA during an adverse scenario called “Emergency Clenching”. To remedy this harmful situation, Bardo OPA was developed by Dr. Theodore Burdumy. The Bardo airway has unique design to transfer the clenching force from incisor to the molar. However, the Bardo OPA is one-sized, and cannot fit most of the patients like the commonly-used OPAs, such as the …

Develop Novel Frap Techniques For Determining Anisotropic Solute Diffusion In Cartilaginous Tissues, Changcheng Shi

All Dissertations

Cartilaginous tissue is a connective tissue composed of specialized cells (e.g., chondrocytes and fibroblasts) that produce a large amount of extracellular matrix (ECM), which is comprised mostly of collagen fibers, abundant ground substance rich in proteoglycan, and elastic fibers. It is characterized by its avascular structures within the tissue, implying that nutrition for normal tissue cells, for maintaining a healthy ECM, is mainly supplied through diffusion from nearby vascularized tissues and synovial fluid. Poor nutritional supply to the cartilaginous tissue is believed to be an important factor leading to tissue degeneration. Moreover, due to the complex collagen fiber structures, the …

On The Importance Of Modeling Stent Procedure For Predicting Arterial Mechanics, Shijia Zhao, Linxia Gu, Stacey R. Froemming

Department of Mechanical and Materials Engineering: Faculty Publications

The stent-artery interactions have been increasingly studied using the finite element method for better understanding of the biomechanical environment changes on the artery and its implications. However, the deployment of balloon-expandable stents was generally simplified without considering the balloon-stent interactions, the initial crimping process of the stent, its overexpansion routinely used in the clinical practice, or its recoil process. In this work, the stenting procedure was mimicked by incorporating all the above-mentioned simplifications. The impact of various simplifications on the stent-induced arterial stresses was systematically investigated. The plastic strain history of stent and its resulted geometrical variations, as well as …

The Effects Of Low Dose Ionizing Radiation Exposure On The Metabolic And Mechanical Properties Of Articular Cartilage, Carl Lindburg

All Theses

Radiation therapy is necessary treatment for many cancer patients due to its non-surgical, yet aggressive and efficacious properties. In fact, over 50% of patients with cancer will undergo some form of radiotherapy during the course of their treatment. While the biological response to ionizing radiation has been examined over the years and many adverse effects have been identified, the effects of radiation on mature cartilage and musculoskeletal tissues are not well understood. Bone, once thought to be a tissue relatively resistant to radiation, has recently been shown to have osteoporosis-like bone atrophy after exposure to low doses (2 Gy) of …

Altered Hemodynamics, Endothelial Function, And Protein Expression Occur With Aortic Coarctation And Persist After Repair, Arjun Menon, Thomas J. Eddinger, Hongfeng Wang, David C. Wendell, Jeffrey M. Toth, John F. Ladisa

Biomedical Engineering Faculty Research and Publications

Coarctation of the aorta (CoA) is associated with substantial morbidity despite treatment. Mechanically induced structural and functional vascular changes are implicated; however, their relationship with smooth muscle (SM) phenotypic expression is not fully understood. Using a clinically representative rabbit model of CoA and correction, we quantified mechanical alterations from a 20-mmHg blood pressure (BP) gradient in the thoracic aorta and related the expression of key SM contractile and focal adhesion proteins with remodeling, relaxation, and stiffness. Systolic and mean BP were elevated for CoA rabbits compared with controls leading to remodeling, stiffening, an altered force response, and endothelial dysfunction both …

Functional Classification Of Skeletal Muscle Networks. I. Normal Physiology, Yu Wang, John Winters, Shankar Subramaniam

Biomedical Engineering Faculty Research and Publications

Extensive measurements of the parts list of human skeletal muscle through transcriptomics and other phenotypic assays offer the opportunity to reconstruct detailed functional models. Through integration of vast amounts of data present in databases and extant knowledge of muscle function combined with robust analyses that include a clustering approach, we present both a protein parts list and network models for skeletal muscle function. The model comprises the four key functional family networks that coexist within a functional space; namely, excitation-activation family (forward pathways that transmit a motoneuronal command signal into the spatial volume of the cell and then use Ca …

The Effect Of Cone Opsin Mutations On Retinal Structure And The Integrity Of The Photoreceptor Mosaic, Joseph Carroll, Alfredo Dubra, Jessica C. Gardner, Liliana Mizrahi-Meissonnier, Robert F. Cooper, Adam M. Dubis, Rick Nordgren, Mohamed Genead, Thomas B. Connor Jr., Kimberly E. Stepien, Dror Sharon, David M. Hunt, Eyal Banin, Alison J. Hardcastle, Anthony T. Moore, David R. Williams, Gerald Fishman, Jay Neitz, Maureen Neitz, Michel Michaelides

Biomedical Engineering Faculty Research and Publications

Purpose.

To evaluate retinal structure and photoreceptor mosaic integrity in subjects with OPN1LW and OPN1MW mutations.

Methods.

Eleven subjects were recruited, eight of whom have been previously described. Cone and rod density was measured using images of the photoreceptor mosaic obtained from an adaptive optics scanning light ophthalmoscope (AOSLO). Total retinal thickness, inner retinal thickness, and outer nuclear layer plus Henle fiber layer (ONL+HFL) thickness were measured using cross-sectional spectral-domain optical coherence tomography (SD-OCT) images. Molecular genetic analyses were performed to characterize the OPN1LW/OPN1MW gene array.

Results.

While disruptions in retinal lamination and cone mosaic structure were observed …