Engineering Commons^™

Gait And Postural Analysis In Healthy Young Adults And People With Parkinson's Disease, Aisha Joy Chen

CGU Theses & Dissertations

Postural analysis is the study of how the position of the body in any mode interacts with internal and external forces. This type of analysis is typically used to assess potential abnormalities in the balance control system and to understand how the balance control system changes with time. However, compared to other medical fields of study, postural analysis is relatively new [1]. In fact, although widely used in clinical and research studies, postural assessment methods are scientifically inaccurate, and some data collection methods are relatively expensive. A better understanding of the human balance control system could lead to more accurate …

Special Collection On Electroporation-Based Therapies: A Selection Of Papers From The Second World Congress On Electroporation, Richard Heller, Rafael V. Davalos

Bioelectrics Publications

No abstract provided.

Mechanical Stresses On Nasal Mucosa Using Nose-On-Chip Model, Zachary Edward Brooks

Browse all Theses and Dissertations

The objective of this research was to design and fabricate a nose-on-chip device and bi-directional airflow system that models flow within the nasal cavity to investigate how airflow induced mechanical stresses impact nasal secretion rates and cytoskeletal remodeling. This research hypothesizes that the airflow induced shear stresses on the nasal mucosa will influence mucus production and the cytoskeleton of the cells. The RPMI 2650 cell line was used to model the nasal mucosa. The system was used to replicate the wall shear stresses (WSS) and wall shear forces (WSF) present in the anterior region of the nose. The WSS and …

Bacterial Cellulose/Alginate/Gelatin Composite Films For Wound Dressing, Nadda Chiaoprakobkij

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research aimed to develop the blended bacterial cellulose (BC)/ alginate (A)/ gelatin (G) incorporating with curcumin (C) for wound dressing application. Fourier transform infrared (FT-IR) spectroscopy showed that the interaction among bacterial cellulose/alginate/gelatin curcumin molecules were only physical but not chemical intermolecular level. Water vapor and oxygen permeabilities of the fabricated films were close to commercially avaialbe wound dressings. Curcumin incorporation lowered fluid absorption ability, water vapor and oxygen permeabilities. In vitro culture of human keratinocytes, and human gingival fibroblasts evidenced that the fabricated composite films could promote cell proliferation. Curcumin-loaded films showed anticancer activity against human oral cancer …

Connecting The Pieces: How Low Back Pain Alters Lower Extremity Biomechanics And Shock Attenuation In Active Individuals, Alexa Johnson

Theses and Dissertations--Rehabilitation Sciences

Low back pain in collegiate athletes has been reported at a rate of 37% from a wide array of sports including soccer, volleyball, football, swimming, and baseball. Whereas, in a military population the prevalence of low back pain is 70% higher than the general population. Compensatory movement strategies are often used as an attempt to reduce pain. Though compensatory movement strategies may effectively reduce pain, they are often associated with altered lower extremity loading patterns. Those who suffer from chronic low back pain tend to walk and run slower and with less trunk and pelvis coordination and variability. Individuals with …

Designing Biomimetic Implant Surfaces To Promote Osseointegration Under Osteoporotic Conditions By Revitalizing Mechanisms Coupling Bone Resorption To Formation, Ethan M. Lotz

Theses and Dissertations

In cases of compromised bone remodeling like osteoporosis, insufficient osseointegration occurs and results in implant failure. Implant retention relies on proper secondary fixation, which is developed during bone remodeling. This process is disrupted in metastatic bone diseases like osteoporosis. Osteoporosis is characterized low bone mass and bone strength resulting from either accelerated osteoclast-mediated bone resorption or impaired osteoblast-mediated bone formation. These two processes are not independent phenomena. In fact, osteoporosis can be viewed as a breakdown of the cellular communication connecting bone resorption to bone formation. Because bone remodeling occurs at temporally generated specific anatomical sites and at different times, …

Monitoring Cerebral Functional Response Using Scmos-Based High Density Near Infrared Spectroscopic Imaging, Dharminder Singh Langri

Browse all Theses and Dissertations

Neurovascular coupling is an important concept that indicates the direct link between neuronal electrical firing with the vascular hemodynamic changes. Functional Near Infrared Spectroscopy (fNIRS) can measure changes in cerebral vascular parameters of oxy-hemoglobin and deoxyhemoglobin concentrations and thus can provide neuronal activity through neurovascular coupling. Currently many commercial fNIRS devices are available, but they are limited by the number of channels (usually having only 8 detectors), which can limit the sensitivity, contrast, and resolution of imaging. High-density imaging can improve sensitivity, contrast, and resolution by providing many measurements and averaging the signals originating from the target cerebral focus area …

The Impact Of Extreme Virtual Elevation Above Grade On Construction Workers' Physiological Responses, Physical Responses, And Task Performance, Mahmoud Habibnezhad

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

On average, in every two work hours, one person dies from work-related injuries at construction sites. Most incidents are due to falling from elevated surfaces. Slips, trips, and loss of balance are the main causes. Studies suggest that instigating visual mismatch and physiological changes are among the most important reasons behind falling from narrow elevated surfaces. By using advanced virtual reality models, this dissertation aims to highlight some of the possible effects of a destabilizing environment (i.e., elevation above grade) on workers’ physiological responses and task performance. More specifically, this dissertation strives to find potential effects of elevation above grade …

A Brain-Computer Interface For Closed-Loop Sensory Stimulation During Motor Training In Patients With Tetraplegia, Sarah Helen Thomas

Theses and Dissertations--Biomedical Engineering

Normal movement execution requires proper coupling of motor and sensory activation. An increasing body of literature supports the idea that incorporation of sensory stimulation into motor rehabilitation practices increases its effectiveness. Paired associative stimulation (PAS) studies, in which afferent and efferent pathways are activated in tandem, have brought attention to the importance of well-timed stimulation rather than non-associative (i.e., open-loop) activation. In patients with tetraplegia resulting from spinal cord injury (SCI), varying degrees of upper limb function may remain and could be harnessed for rehabilitation. Incorporating associative sensory stimulation coupled with self-paced motor training would be a means for supplementing …

A Possible Link Between R-Wave Amplitude Alternans And T-Wave Alternans In Ecgs, Sahar Alaei

Theses and Dissertations--Biomedical Engineering

Sudden Cardiac Death (SCD) is the largest cause of natural deaths in the USA, accounting for over 300,000 deaths annually. The major reason for SCD is Ventricular Arrhythmia (VA). Therefore, there is need for exploration of approaches to predict increased risk for VA. Alternans of the T wave in the ECG (TWA) is widely investigated as a potential predictor of VA, however, clinical trials show that TWA has high negative predictive value but poor positive predictive value. A possible reason that TWA has a large number of false positives is that a pattern of alternans known as concordant alternans, may …

Calibrated Short Tr Recovery Mri For Rapid Measurement Of Brain-Blood Partition Coefficient And Correction Of Quantitative Cerebral Blood Flow, Scott William Thalman

Theses and Dissertations--Biomedical Engineering

The high prevalence and mortality of cerebrovascular disease has led to the development of several methods to measure cerebral blood flow (CBF) in vivo. One of these, arterial spin labeling (ASL), is a quantitative magnetic resonance imaging (MRI) technique with the advantage that it is completely non-invasive. The quantification of CBF using ASL requires correction for a tissue specific parameter called the brain-blood partition coefficient (BBPC). Despite regional and inter-subject variability in BBPC, the current recommended implementation of ASL uses a constant assumed value of 0.9 mL/g for all regions of the brain, all subjects, and even all species.

The …

Biomechanical Effects Of A Hip Orthosis On Lumbo-Pelvic Coordination, Matthew Ballard

Theses and Dissertations--Biomedical Engineering

Abnormal lumbar movement has been observed in individuals who have a history of low back pain (LBP). Affected individuals display a reduction in lumbar spine rotation during trunk movement tasks, while pelvic rotation increases to compensate. Reduced lumbar contribution to forward bending is associated with increased compressive forces and increased shearing demand of the task on the lower back. This abnormal lumbo-pelvic coordination (LPC) can persist beyond LBP symptom alleviation and may contribute to further occurrences or more severe cases of LBP. This study serves as a first step in investigating if abnormal LPC can be corrected with a hip …

Noninvasive Multimodal Diffuse Optical Imaging Of Vulnerable Tissue Hemodynamics, Mingjun Zhao

Theses and Dissertations--Biomedical Engineering

Measurement of tissue hemodynamics provides vital information for the assessment of tissue viability. This thesis reports three noninvasive near-infrared diffuse optical systems for spectroscopic measurements and tomographic imaging of tissue hemodynamics in vulnerable tissues with the goal of disease diagnosis and treatment monitoring. A hybrid near-infrared spectroscopy/diffuse correlation spectroscopy (NIRS/DCS) instrument with a contact fiber-optic probe was developed and utilized for simultaneous and continuous monitoring of blood flow (BF), blood oxygenation, and oxidative metabolism in exercising gastrocnemius. Results measured by the hybrid NIRS/DCS instrument in 37 subjects (mean age: 67 ± 6) indicated that vitamin D supplement plus aerobic training …

Investigating The Feasibility Of Using Mesoporous Silica Particles To Deliver Glucose During Anaerobic Fermentation, Megan E. Walz

Theses and Dissertations--Biosystems and Agricultural Engineering

The study presented herein investigated a potential low-energy method to separate and concentrate glucose from a lignocellulosic hydrolysate. The motivation for this method was twofold: 1) to provide the fermentation microorganism an optimal glucose concentration and 2) to supply a fermentation media free of inhibitory compounds. Two sizes of porous silica particles (with 7 nm and 2.3 nm pores) were synthesized and their ability to adsorb glucose from solution confirmed. Next, the ability of two different microorganisms, Saccharomyces cerevisiae and Streptococcus bovis, to utilize sugars adsorbed to the porous silica particles was investigated.

Both the 7 nm and 2.3 …

Quantification Of Myocardial Mechanics In Left Ventricles Under Inotropic Stimulation And In Healthy Right Ventricles Using 3d Dense Cmr, Zhan-Qiu Liu

Theses and Dissertations--Mechanical and Aerospace Engineering

Statistical data from clinical studies indicate that the death rate caused by heart disease has decreased due to an increased use of evidence-based medical therapies. This includes the use of magnetic resonance imaging (MRI), which is one of the most common non-invasive approaches in evidence-based health care research. In the current work, I present 3D Lagrangian strains and torsion in the left ventricle of healthy and isoproterenol-stimulated rats, which were investigated using Displacement ENcoding with Stimulated Echoes (DENSE) cardiac magnetic resonance (CMR) imaging. With the implementation of the 12-segment model, a detailed profile of regional cardiac mechanics was reconstructed for …

Estimating The Spectrum In Computed Tomography Via Kullback–Leibler Divergence Constrained Optimization, Wooseok Ha, Emil Y. Sidky, Rina Foygel Barber, Taly Gilat Schmidt, Xiaochuan Pan

Biomedical Engineering Faculty Research and Publications

Purpose

We study the problem of spectrum estimation from transmission data of a known phantom. The goal is to reconstruct an x‐ray spectrum that can accurately model the x‐ray transmission curves and reflects a realistic shape of the typical energy spectra of the CT system.

Methods

Spectrum estimation is posed as an optimization problem with x‐ray spectrum as unknown variables, and a Kullback–Leibler (KL)‐divergence constraint is employed to incorporate prior knowledge of the spectrum and enhance numerical stability of the estimation process. The formulated constrained optimization problem is convex and can be solved efficiently by use of the exponentiated‐gradient (EG) …

Exploring The Role And Impact Of Microscale Phenomena On Electrode, Microdevice, And Cellular Function, Sanaz Habibi

Dissertations, Master's Theses and Master's Reports

Microfluidic technologies enable the development of portable devices to perform multiple high-resolution unit operations with small sample and reagent volumes, low fabrication cost, facile operation, and quick response times. Microfluidic platforms are expected to effectively interpret both wanted and unwanted phenomena; however, a comprehensive evaluation of the unwanted phenomena has not been appropriately investigated in the literature. This work explored an attenuative evaluation of unwanted phenomena, also called here as secondary phenomena, in a unique approach.

Upon electric field utilization within microfluidic devices, electrode miniaturization improves device sensitivity. However, electrodes in contact with medium solution can yield byproducts that can …

Optical Vortex And Poincaré Analysis For Biophysical Dynamics, Anindya Majumdar

Dissertations, Master's Theses and Master's Reports

Coherent light - such as that from a laser - on interaction with biological tissues, undergoes scattering. This scattered light undergoes interference and the resultant field has randomly added phases and amplitudes. This random interference pattern is known as speckles, and has been the subject of multiple applications, including imaging techniques. These speckle fields inherently contain optical vortices, or phase singularities. These are locations where the intensity (or amplitude) of the interference pattern is zero, and the phase is undefined.

In the research presented in this dissertation, dynamic speckle patterns were obtained through computer simulations as well as laboratory setups …

Estimation Of Multi-Directional Ankle Impedance As A Function Of Lower Extremity Muscle Activation, Lauren Knop

Dissertations, Master's Theses and Master's Reports

The purpose of this research is to investigate the relationship between the mechanical impedance of the human ankle and the corresponding lower extremity muscle activity. Three experimental studies were performed to measure the ankle impedance about multiple degrees of freedom (DOF), while the ankle was subjected to different loading conditions and different levels of muscle activity. The first study determined the non-loaded ankle impedance in the sagittal, frontal, and transverse anatomical planes while the ankle was suspended above the ground. The subjects actively co-contracted their agonist and antagonistic muscles to various levels, measured using electromyography (EMG). An Artificial Neural Network …

A Smart Implantable Bone Fixation Plate Providing Actuation And Load Monitoring For Orthopedic Fracture Healing, Brad Nelson

Dissertations, Master's Theses and Master's Reports

Fracture non-union occurs in roughly 5-10% of all fracture cases, and current interventions are both time-consuming and costly. There is therefore significant incentive to develop new tools to improve fracture healing outcomes. Several studies have shown that low-magnitude, high-frequency (LMHF) mechanical loading can promote faster healing and reduce the risk of refracture in critical-size long bone fractures. This is typically done using whole-body vibration, which may result in undesirable systemic effects on the rest of the body. This work discusses an implantable piezoelectric fixation plate that can both apply LMHF loading directly to the fracture site using flexible scheduling and …

3d Printing In Low Resource Healthcare Settings: Analysis Of Potential Implementations, Alenna Beroza

Dissertations, Master's Theses and Master's Reports

3D printing has gained significant momentum in the past ten years, and its unique advantages make it especially ideal for use in low resource healthcare settings, where many designs have already been successfully implemented. Yet, little has been studied on how 3D printing can be sustainably and functionally implemented in low resource healthcare systems as a manufacturing practice. In this report, three business models are proposed for this implementation: In-House Operator, Independent Operator, and Print Farm. These models were then tested over four months in Kisumu county, Kenya, at two workshops and seven public hospitals. I worked with local medical …

Degradable Zinc Material Characteristics And Its Influence On Biocompatibility In An In-Vivo Murine Model, Roger J. Guillory Ii

Dissertations, Master's Theses and Master's Reports

Biodegradable stents based on zinc have been under development since their introduction in 2013. While metallic zinc is highly ductile, it unfortunately lacks the mechanical strength required for arterial stents. This has led to the development of an abundance of novel zinc-based materials, with the aim of improving the mechanical strength without sacrificing too much ductility. Although these materials are intended to function and slowly degrade within an artery, most zinc-based materials have been developed without deep consideration for their biological effects.

The present work explores the biological effects elicited by zinc-based materials implanted within the arterial system. The biological …

Upright Sleep Device For Patients Required To Sleep Upright Post Surgery/Medical Procedure, Kristin J. Abele, Madeleine H. Hummel, Tayler R. Kastlunger

Biomedical Engineering

No abstract provided.

Surf Leg, Samantha Campbell, Oyundari Altansukh, Caroline Swanson, Kurtis Barth

Mechanical Engineering

The Surf Leg Prosthetic project team in conjunction with QL+ and Operation Surf designed a transtibial prosthetic to be used for surfing. The senior project team focused on the missions of QL+ and Operation Surf as they went through the design process during the 2018-2019 academic year. The problem solved was that a standard prosthetic for a transtibial amputee does not provide the flexibility in enough degrees of freedom for a user to squat and balance on a surfboard. The goal of this project was to create a device specifically designed to improve the user’s balance and control while surfing. …

Modification Of Lipid Microenvironments On Solid Support Structures For Use In Transmembrane Protein Assays, William J. Houlihan

Dissertations and Theses

Gamma-Secretase (γ-secretase) is a transmembrane protease of increasing interest, which has been shown to have significant connections to both cancer and Alzheimer’s disease. γ-secretase cleaves both Notch-1, a transmembrane signaling protein, and Amyloid precursor protein (APP), a transmembrane protein whose cleavage may result in the formation of β-amyloid plaques in the brain. Notch-1 and APP are widely studied proteins that have substantial impacts on the development and proliferation of cancer and Alzheimer’s disease, respectively. Notch-1 partakes in the signaling of apoptosis in damaged and mutated cells, thus its cleavage by γ-secretase within the plasma membrane has ramifications on cell growth …

Glioma Grading Using Structural Magnetic Resonance Imaging And Molecular Data, Syed M.S. Reza, Manar D. Samad, Zeina A. Shboul, Karra A. Jones, Khan M. Iftekharuddin

Electrical & Computer Engineering Faculty Publications

A glioma grading method using conventional structural magnetic resonance image (MRI) and molecular data from patients is proposed. The noninvasive grading of glioma tumors is obtained using multiple radiomic texture features including dynamic texture analysis, multifractal detrended fluctuation analysis, and multiresolution fractal Brownian motion in structural MRI. The proposed method is evaluated using two multicenter MRI datasets: (1) the brain tumor segmentation (BRATS-2017) challenge for high-grade versus low-grade (LG) and (2) the cancer imaging archive (TCIA) repository for glioblastoma (GBM) versus LG glioma grading. The grading performance using MRI is compared with that of digital pathology (DP) images in the …

End-To-End Learning Via A Convolutional Neural Network For Cancer Cell Line Classification, Darlington A. Akogo, Xavier-Lewis Palmer

Electrical & Computer Engineering Faculty Publications

Purpose: Computer vision for automated analysis of cells and tissues usually include extracting features from images before analyzing such features via various machine learning and machine vision algorithms. The purpose of this work is to explore and demonstrate the ability of a Convolutional Neural Network (CNN) to classify cells pictured via brightfield microscopy without the need of any feature extraction, using a minimum of images, improving work-flows that involve cancer cell identification.

Design/methodology/approach: The methodology involved a quantitative measure of the performance of a Convolutional Neural Network in distinguishing between two cancer lines. In their approach, they trained, validated and …

1995-2005: A Decade Of Innovation In Low Temperature Plasma And Its Applications, Mounir Laroussi

Electrical & Computer Engineering Faculty Publications

Scientific breakthroughs tend to come in spurts when unique societal, economical, and political circumstances conspire (knowingly or unknowingly) and create an environment ripe for creativity. The field of low temperature plasma (LTP) recently experienced such an upheaval, which this paper attempts to relate in some details. There have been “roadmap” papers published before, which look towards the future of the field, but all roads start somewhere and even “new” roads are often paved over older roads that were discovered and traveled by early pioneers. With the sharp decrease in funding for fusion research in the USA in the early 1990s …

Special Issue On Low Temperature Plasma Jets, Mounir Laroussi

Electrical & Computer Engineering Faculty Publications

[Introduction] Low temperature plasma jets are unique plasma sources capable of delivering plasma outside of the confinement of electrodes and away from gas enclosures/chambers. With these jets plasma can be easily delivered to a target located at some distance from the plasma generation region [1].

Multiscale Mathematical Modelling Of Nonlinear Nanowire Resonators For Biological Applications, Rosa Fallahpourghadikolaei

Theses and Dissertations (Comprehensive)

Nanoscale systems fabricated with low-dimensional nanostructures such as carbon nanotubes, nanowires, quantum dots, and more recently graphene sheets, have fascinated researchers from different fields due to their extraordinary and unique physical properties. For example, the remarkable mechanical properties of nanoresonators empower them to have a very high resonant frequency up to the order of giga to terahertz. The ultra-high frequency of these systems attracted the attention of researchers in the area of bio-sensing with the idea to implement them for detection of tiny bio-objects. In this thesis, we originally propose and analyze a mathematical model for nonlinear vibrations of nanowire …