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McKelvey School of Engineering Theses & Dissertations

2022

Articles 1 - 16 of 16

Full-Text Articles in Biomedical Engineering and Bioengineering

Computational Fluid Dynamics Modeling Of Hemodialysis In Patients With An Arteriovenous Fistula, Maximilian Roth Dec 2022

Computational Fluid Dynamics Modeling Of Hemodialysis In Patients With An Arteriovenous Fistula, Maximilian Roth

McKelvey School of Engineering Theses & Dissertations

With the advent of arteriovenous fistula (AVF) for use in hemodialysis, the anastomosis built for such use has become a central point of the study to understand the flow and wall shear stresses in such a system since very large wall shear stresses can lead to arterial/vein rupture. Considering the commonly used creation site of an anastomosis as connecting the radial artery to the cephalic vein, a model is created to calculate the wall shear stresses across various components of the system. The model depicts a connection of the specified vein and artery bridged together allowing the increase in blood …


The Influence Of Electrical Stimulation Pulse Frequency Of Macro-Sieve Electrode On Rat Sciatic Nerve Detection Threshold, Jingyuan Zhang Dec 2022

The Influence Of Electrical Stimulation Pulse Frequency Of Macro-Sieve Electrode On Rat Sciatic Nerve Detection Threshold, Jingyuan Zhang

McKelvey School of Engineering Theses & Dissertations

No abstract provided.


Development Of Optical Coherence Tomography Angiography System For Mouse Eye Imaging And Measurement Of Vasodilation, Yilin Li Dec 2022

Development Of Optical Coherence Tomography Angiography System For Mouse Eye Imaging And Measurement Of Vasodilation, Yilin Li

McKelvey School of Engineering Theses & Dissertations

Optical coherence tomography angiography (OCTA) is broadly known as a non-invasive technology that allows examining the retinal and choroidal vasculatures, alternative to fluorescein angiography. In this study, we have developed an optical coherence tomography (OCT) system for imaging the mouse eye. We measure the retinal thickness, which is 216.53um. We apply OCTA to characterize the quantitative change in vessel diameter and the perfusion density of the retina after the wild-type mice are administered the adenosine or inhale carbon dioxide. Comparing the images acquired one minute and 5 minutes after the injection or CO2 inhalation with the baseline, distinct changes …


Understanding Control Of Metabolite Dynamics And Heterogeneity, Christopher John Hartline Aug 2022

Understanding Control Of Metabolite Dynamics And Heterogeneity, Christopher John Hartline

McKelvey School of Engineering Theses & Dissertations

Microbes live in complex and continually changing environments. Rapid shifts in nutrient availability are a common challenge for microbes, and cause changes in intracellular metabolite levels. Microbial response to dynamic environments requires coordination of multiple levels of cellular machinery including gene expression and metabolite concentrations. This coordination is achieved through metabolic control systems, which sense metabolite concentrations and direct cellular activity in response. Several reoccurring control architectures are found throughout diverse metabolic systems, which suggests underlying evolutionary advantages for using these control systems to coordinate metabolism. One common, yet understudied, control architecture is the positive feedback metabolite uptake loop, which …


Measuring G Protein Activation With Spectrally Resolved Fluorescence Fluctuation Spectroscopy, Daniel Foust Aug 2022

Measuring G Protein Activation With Spectrally Resolved Fluorescence Fluctuation Spectroscopy, Daniel Foust

McKelvey School of Engineering Theses & Dissertations

Fluorescence fluctuation spectroscopy (FFS) is comprised of a set of statistical techniques used to learn information about fluorescence particles by analyzing intensity fluctuations in signals detected from a fluorescence spectrometer or microscope. In biological contexts, FFS is commonly used to quantify the concentrations, molecular brightnesses, and transport properties (e.g. diffusion coefficients) of labeled biomolecules. In particular, the molecular brightness parameter is valuable because it can be used to quantify oligomerization of biomolecules. Therefore, FFS has emerged as an attractive tool for measuring protein-protein interactions in live cells. This dissertation describes the development of image-based, multicolor FFS techniques. Image-based FFS is …


Focused Ultrasound-Enabled Blood-Based Liquid Biopsy (Sonobiopsy) For Brain Disease Diagnosis, Christopher Pham Pacia Aug 2022

Focused Ultrasound-Enabled Blood-Based Liquid Biopsy (Sonobiopsy) For Brain Disease Diagnosis, Christopher Pham Pacia

McKelvey School of Engineering Theses & Dissertations

Brain cancer severely threatens human health due to its disruption of neurological function, poor prognosis, and substantial reduction in quality of life. Glioblastoma (GBM) is the most devastating brain cancer; not only is it the most common malignant primary tumor in adults, but also it has a median survival of 14 months with a 5-year survival rate of less than 5%. Despite advances in multidisciplinary treatment that includes surgical resection, radiation therapy, and chemotherapy, almost all patients experience tumor progression and nearly universal mortality within 2 years. However, advances in patient care have suggested that the accurate diagnosis of molecular …


Imaging Techniques For Proton Range Determination In Proton Therapy, Xinyuan Chen Aug 2022

Imaging Techniques For Proton Range Determination In Proton Therapy, Xinyuan Chen

McKelvey School of Engineering Theses & Dissertations

Proton therapy can achieve better sparing of normal tissues than the conventional photon radiation therapy due to proton’s Bragg Peak property. However, to unlock the full potential of protons, accurate prediction of in vivo proton stopping power ratio (SPR) is required for proton therapy treatment planning. The current standard practice is to map SPR from Hounsfield Unit (HU) values of a single-energy computed tomography (SECT) scan through a stoichiometric calibration technique. This technique is subjected to a variety of factors that congregate on the uncertainties in SPR estimation, including the calibration uncertainty (up to 0.5% to 1.8% of the total …


Plasmonic Nanomaterials-Based Point-Of-Care Biosensors, Rohit Gupta Aug 2022

Plasmonic Nanomaterials-Based Point-Of-Care Biosensors, Rohit Gupta

McKelvey School of Engineering Theses & Dissertations

Point-of-care (POC) biosensors, although rapid and easy-to-use, are orders magnitude less sensitive than laboratory-based tests. Further they are plagued by poor stability of recognition element thus limiting its widespread applicability in resource-limited settings. Therefore, there is a critical need for realizing stable POC biosensors with sensitivity comparable to gold-standard laboratory-based tests. This challenge constitutes the fundamental basis of this dissertation work– to expand access to quality and accurate biodiagnostic tools. At the heart of these solutions lies plasmonic nanoparticles which exhibit unique optical properties which are attractive for label-free and labelled biosensors.Firstly, we improve the stability and applicability of label-free …


Ligand- And Strain-Specific Control Of Microbial Communities, Austin Grant Rottinghaus Aug 2022

Ligand- And Strain-Specific Control Of Microbial Communities, Austin Grant Rottinghaus

McKelvey School of Engineering Theses & Dissertations

Microbes naturally coexist in complex, multi-strain communities that are valuable assets for their host. Commensal and probiotic microbes prevent pathogen colonization, reduce the frequency and severity of various ailments, provide essential nutrients, and offer various additional benefits. Understanding the dynamics of and tailoring microbial communities to provide additional beneficial functions is a primary focus of researchers in medicine and agriculture. To date, consortia have primarily been manipulated by supplementing the communities with microbes that were engineered in vitro or by introducing stimuli that alter the metabolism or composition of the community. This method has proven successful, with numerous microbes engineered …


Development Of The Assessment Of Clinical Prediction Model Transportability (Apt) Checklist, Sean Chonghwan Yu Aug 2022

Development Of The Assessment Of Clinical Prediction Model Transportability (Apt) Checklist, Sean Chonghwan Yu

McKelvey School of Engineering Theses & Dissertations

Clinical Prediction Models (CPM) have long been used for Clinical Decision Support (CDS) initially based on simple clinical scoring systems, and increasingly based on complex machine learning models relying on large-scale Electronic Health Record (EHR) data. External implementation – or the application of CPMs on sites where it was not originally developed – is valuable as it reduces the need for redundant de novo CPM development, enables CPM usage by low resource organizations, facilitates external validation studies, and encourages collaborative development of CPMs. Further, adoption of externally developed CPMs has been facilitated by ongoing interoperability efforts in standards, policy, and …


Development Of Noninvasive Biomarkers For Cervical Spondylotic Myelopathy, Dinal Jayasekera Aug 2022

Development Of Noninvasive Biomarkers For Cervical Spondylotic Myelopathy, Dinal Jayasekera

McKelvey School of Engineering Theses & Dissertations

Cervical spondylotic myelopathy (CSM) represents the most common cause of chronic spinal cord injury (SCI) in adults. Many patients with symptomatic CSM will experience a decline in neurological function and consequently undergo surgical decompression. Unfortunately, surgeons are unable to adequately counsel patients about the benefits of surgery because the natural history of disease and outcome after decompression vary widely among patients. This can hinder the decision-making capacity of patients and physicians. Therefore, we require additional tools to help guide therapy and counsel patients with CSM. Noninvasive biomarkers present valuable potential as predictors of a patient’s recovery in the long term. …


Role Of Ligand Architecture On Collective Cell Invasion, Amrit Bagchi Aug 2022

Role Of Ligand Architecture On Collective Cell Invasion, Amrit Bagchi

McKelvey School of Engineering Theses & Dissertations

Epithelial cell collectives utilize extra-cellular matrix (ECM) fibers to undergo collective migration critical in regeneration, repair and cancer metastasis. However, very little is known about the various factors which determine the ability of cellular collectives to utilize ECM fibers to undergo these critical processes in-vivo. First part of the dissertation focusses on understanding how cell collectives exploit specific properties, like stiffness and fiber length to undergo collective streaming. It is also unclear how cellular forces, cell-cell adhesion, and velocities are coordinated within streams. To independently tune stiffness and collagen fiber length, we developed new hydrogels and discovered invasion-like streaming of …


Evaluation And Clinical Implementation Of A Dual-Energy Ct Stopping-Power Ratio Mapping Technique For Proton-Therapy Treatment Planning, Maria Jose Medrano Matamoros Aug 2022

Evaluation And Clinical Implementation Of A Dual-Energy Ct Stopping-Power Ratio Mapping Technique For Proton-Therapy Treatment Planning, Maria Jose Medrano Matamoros

McKelvey School of Engineering Theses & Dissertations

Proton radiotherapy has the potential to treat tumors with better conformal dose distribution than competing modalities when the rapid dose falloff at the end of the proton-beam range is correctly aligned to the edge of the clinical target volume (CTV). However, its clinical potential is dependent on the accurate localization of the Bragg-peak position from predicted stopping-power ratio maps. The method that is most commonly used in today’s clinical practice for predicting stopping-power ratio (SPR) consists of a stoichiometric calibrationtechnique based on single-energy CT (SECT) for direct estimation of patient-specific SPR distribution from vendor-reconstructed Hounsfield Unit (HU) images. Unfortunately, this …


Fast And Radiation-Free High-Resolution Mr Cranial Bone Imaging For Pediatric Patients, Parna Eshraghi Boroojeni Aug 2022

Fast And Radiation-Free High-Resolution Mr Cranial Bone Imaging For Pediatric Patients, Parna Eshraghi Boroojeni

McKelvey School of Engineering Theses & Dissertations

AbstractEach year, 2.2 million pediatric head computed tomography (CT) scans are performed in the United States. Head trauma and craniosynostosis are two of the most common pediatric conditions requiring head CT scans. Head trauma is common in children and one-third of the patients that present to the emergency room undergoes head CT imaging. Craniosynostosis is a congenital disability defined by a prematurely fused cranial suture. Standard clinical care for pediatric patients with head trauma or craniosynostosis uses high-resolution head CT to identify cranial fractures or cranial sutures. Unfortunately, the ionizing radiation of CT imaging imposes a risk to patients, particularly …


Application Of Neural Networks To Predict Patient-Specific Cellular Parameters In Computational Cardiac Models, Chang Hi Lee May 2022

Application Of Neural Networks To Predict Patient-Specific Cellular Parameters In Computational Cardiac Models, Chang Hi Lee

McKelvey School of Engineering Theses & Dissertations

Sudden cardiac death(SCD) is a significant cause of death that accounts for more than 180,000 deaths in the US and 4 million deaths worldwide annually. SCDs are mainly caused by irregular heartbeats called arrhythmias, which are caused by abnormal electrical activity within the heart. Precision medicine, in the form of personalized computational cardiac models of a patient’s heart, can suggest optimal therapies for cardiac arrhythmias. Prior work has used finite element meshes derived from cardiac MRIs to simulate cardiac electrical activity. In this study, I sought to augment this approach by developing a neural network to learn the parameters that …


Active Testing Of Executive Functions: Toward More Efficient And Equitable Individual Behavioral Modeling, Mariluz Rojo Domingo May 2022

Active Testing Of Executive Functions: Toward More Efficient And Equitable Individual Behavioral Modeling, Mariluz Rojo Domingo

McKelvey School of Engineering Theses & Dissertations

Inferences about executive functions are commonly drawn through serial administration of various individual assessments that often take a long time to complete and cannot capture complex trends across multiple variables. In an attempt to improve upon current methods used to estimate latent brain constructs, this thesis makes two primary contributions to the field of behavioral modeling. First, it brings attention to sequential designs for more efficient diagnostic testing of fluctuations in executive functions with respect to a baseline level. It was shown that a sequential framework was successfully capable of detecting significant differences in cognitive performance more rapidly than conventional …