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Washington University in St. Louis

Theses/Dissertations

2022

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Full-Text Articles in Engineering

Three-Component Composite Phase-Change Material For Thermal Regulation, Bidisha Ojha Dec 2022

Three-Component Composite Phase-Change Material For Thermal Regulation, Bidisha Ojha

McKelvey School of Engineering Theses & Dissertations

Phase change materials can increase the efficiency of many energy-intensive applications, such as solar power plants, solar heating and cooling systems, heat recovery systems, photovoltaic electricity systems, and Earth satellite systems. In several proposed thermal management systems for high power electronic equipment, PCMs change phase and absorb latent heat at peak energy loads during operation, then dissipate this energy later to prevent overheating. More specifically, composite PCM’s, consisting of an organic material (e.g., paraffin) and an inorganic material (e.g., metallic alloys or salt hydrates), provide a superior balance of thermal conductivity and latent heat for thermal management. Organic PCMs have …


Effect Of Diabetes-Associated Mutations In Kir 6.2/Sur1 On Katp Channel Activities, Yunpeng Li Dec 2022

Effect Of Diabetes-Associated Mutations In Kir 6.2/Sur1 On Katp Channel Activities, Yunpeng Li

McKelvey School of Engineering Theses & Dissertations

Maturity Onset Diabetes of the Young (MODY) is a type of diabetes, distinct from either type I or type II, that happens before age 25 (MedlinePlus, 2022). Unlike the other two more common forms of diabetes, MODY is classified as a series of monogenetic disorders (American Diabetes Association Professional Practice Committee, 2021), caused by autosomal mutations. MODY is typically characterized by insufficient secretion of insulin, a similar symptom to type I diabetes, classified into 14 different types based on mutations found on different genes. Among them, subtypes 12 and 13, also called neonatal diabetes mellitus (NDM), are caused by gain-of-function …


The Role Of The Neurodevelopmental Disorder Gene Myt1l In Mammalian Brain Development, Jiayang Chen Dec 2022

The Role Of The Neurodevelopmental Disorder Gene Myt1l In Mammalian Brain Development, Jiayang Chen

Arts & Sciences Electronic Theses and Dissertations

Recent human genetic studies have associated mutations in a gene called Myelin Transcription Factor 1 Like (MYT1L) with neurodevelopmental disorders (NDDs). Patients with MYT1L loss of function (LoF) mutations (MYT1L Syndrome patients) demonstrate shared symptoms such as microcephaly, attention deficit and hyperactivity disorder (ADHD), and obesity. Despite prior studies showing MYT1L overexpression facilitates neuronal differentiation in vitro, its functions in vivo, especially in the mammalian brain, and how its mutation leads to human disease pathology remains poorly understood. Here, I established the first mouse model of MYT1L Syndrome mimicking a patient specific LoF mutation. I found mice with Myt1l heterozygous …


Functionalized Plasmonic Nanostructures For Ultrasensitive Single Cell Analysis, Priya Rathi Dec 2022

Functionalized Plasmonic Nanostructures For Ultrasensitive Single Cell Analysis, Priya Rathi

Arts & Sciences Electronic Theses and Dissertations

Ultrasensitive detection and quantification of soluble, secreted and cell surface-bound proteins is critical for advancing our understanding of cellular systems, enabling effective drug development, novel therapies, and bio-diagnostics. However, exiting technologies are largely limited by their sensitivity, making the detection and quantification of low-abundant proteins extremely challenging. This forms a major barrier in various fields of biology and biomedical sciences. In this work, we introduce novel cellular analysis methodologies based on plasmon-enhanced fluorescence for analyzing cell structure and probing surface and secreted proteins from cells. In the first part, we introduce plasmon-enhanced expansion microscopy and demonstrate the effectiveness of employing …


The Effect Of Ionization Density In Applications Of Radiation Detection, Dosimetry, And Therapy, Daniel Mulrow Dec 2022

The Effect Of Ionization Density In Applications Of Radiation Detection, Dosimetry, And Therapy, Daniel Mulrow

Arts & Sciences Electronic Theses and Dissertations

This dissertation covers a wide range of topics but is linked by the common theme of radiation interacting with materials and studying the result of those interactions. The introduction describes the fundamentals of how radiation interacts with material and how we are able to detect that radiation and the application of how we use those interactions in radiation oncology. The thesis starts with a chapter detailing the temperature dependence of the photophysics in two organic scintillators. This chapter is the foundation for a future study that will look the degree to which these scintillators can distinguish between gammas and neutrons …


Investigating Applications Of Deep Learning For Diagnosis Of Post Traumatic Elbow Disease, Hugh James Dec 2022

Investigating Applications Of Deep Learning For Diagnosis Of Post Traumatic Elbow Disease, Hugh James

McKelvey School of Engineering Theses & Dissertations

Traumatic events such as dislocation, breaks, and arthritis of musculoskeletal joints can cause the development of post-traumatic joint contracture (PTJC). Clinically, noninvasive techniques such as Magnetic Resonance Imaging (MRI) scans are used to analyze the disease. Such procedures require a patient to sit sedentary for long periods of time and can be expensive as well. Additionally, years of practice and experience are required for clinicians to accurately recognize the diseased anterior capsule region and make an accurate diagnosis. Manual tracing of the anterior capsule is done to help with diagnosis but is subjective and timely. As a result, there is …


Applying Hls To Fpga Data Preprocessing In The Advanced Particle-Astrophysics Telescope, Meagan Konst Dec 2022

Applying Hls To Fpga Data Preprocessing In The Advanced Particle-Astrophysics Telescope, Meagan Konst

McKelvey School of Engineering Theses & Dissertations

The Advanced Particle-astrophysics Telescope (APT) and its preliminary iteration the Antarctic Demonstrator for APT (ADAPT) are highly collaborative projects that seek to capture gamma-ray emissions. Along with dark matter and ultra-heavy cosmic ray nuclei measurements, APT will provide sub-degree localization and polarization measurements for gamma-ray transients. This will allow for devices on Earth to point to the direction from which the gamma-ray transients originated in order to collect additional data. The data collection process is as follows. A scintillation occurs and is detected by the wavelength-shifting fibers. This signal is then read by an ASIC and stored in an ADC …


Dei Without Equity: Lab Coat Culture And Persistent Racism In Bioengineering Laboratories, Janet Canady Dec 2022

Dei Without Equity: Lab Coat Culture And Persistent Racism In Bioengineering Laboratories, Janet Canady

Arts & Sciences Electronic Theses and Dissertations

From biased algorithms to discriminatory devices to medical racism, it is clear that biomedical products are created in ways that reproduce racial disparities in access and use. Yet the most common solutions recommended by biomedical research institutions emphasize diversity, equity, and inclusion practices that research has already proven ineffective and sometimes harmful. In fact, labs rarely scrutinize whether and how their research products reflect racial bias, assumptions, or ideals. In this paper, I shift the focus to consider how bioengineering laboratories function as a site in which racial processes contribute to product outcomes. I ask, what are the racial dynamics …


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 …


Optogenetic Heart Pacing And Heart Arrest In Drosophila Melanogaster Using Integrated Ocm Imaging And Light Stimulation System, Yuxuan Wang Dec 2022

Optogenetic Heart Pacing And Heart Arrest In Drosophila Melanogaster Using Integrated Ocm Imaging And Light Stimulation System, Yuxuan Wang

McKelvey School of Engineering Theses & Dissertations

Optogenetics has been widely applied to cardiovascular research using different models. Among them, Drosophila melanogaster (fruit fly) outstands for its similarity of human genes for disease modeling and short life cycle for rapid screening to analyze genetic mechanisms of heart disease. However, most of the current models only allow either activation or inhibition of the heartbeat, which is not sufficient to model complex arrhythmia. Our lab developed a novel Drosophila transgenic model based on a double transgenic line containing two light-sensitive genes, Channelrhodopsin-2 (ChR2) and Halorhodopsin2.0 (NpHR2.0), that enable dual-directional control of the heartbeat rhythm. Real-time optical control of the …


Measuring The Effectiveness Of Light Concentration With The Catoptric Surface, Samatha Kodali Dec 2022

Measuring The Effectiveness Of Light Concentration With The Catoptric Surface, Samatha Kodali

McKelvey School of Engineering Theses & Dissertations

The Catoptric Surface is an array of mirrors arranged on the interior of a large window which serves to manipulate the effects of natural lighting inside the room. The framework for moving the mirrors uses an interface which connects various Raspberry Pis and Arduino Unos to move stepper motors that connect to each mirror and move them as desired by the user. This kind of light manipulation allows the atmosphere of the room to be modified using natural lighting rather than artificial lighting and can be useful for varying the way people interact with a space. The intensity at which …


Validation And Verification Of The Wray-Agarwal Turbulence And Algebraic Transition Models For 2d External Airfoil Flows, Dean Ryan-Simmons Oct 2022

Validation And Verification Of The Wray-Agarwal Turbulence And Algebraic Transition Models For 2d External Airfoil Flows, Dean Ryan-Simmons

McKelvey School of Engineering Theses & Dissertations

Validation and verification benchmark test cases are employed in computational fluid dynamics (CFD) to determine the best practices in application of various CFD tools. These cases focus on the geometry modeling, mesh generation, numerical algorithms, and turbulence models to ensure consistent and accurate numerical simulation of physical phenomena. Assessing model accuracy is essential to identify areas of improvement in various turbulence models. Flow past several symmetric NACA airfoils, namely NACA 0012, NACA 0015 and NACA 0018 are standard test cases for validating and evaluating turbulence models’ accuracy since the experimental data is available for these airfoils. Available wind tunnel data …


Speeding Up The Quantification Of Contrast Sensitivity Functions Using Multidimensional Bayesian Active Learning, Shohaib Shaffiey Aug 2022

Speeding Up The Quantification Of Contrast Sensitivity Functions Using Multidimensional Bayesian Active Learning, Shohaib Shaffiey

McKelvey School of Engineering Theses & Dissertations

No abstract provided.


Modeling Solvent Extraction Of Lignin From Hardwoods, Su Pan Aug 2022

Modeling Solvent Extraction Of Lignin From Hardwoods, Su Pan

McKelvey School of Engineering Theses & Dissertations

This study interprets the observed behavior of solvent extraction of lignin from hardwoods by adapting the framework of the FLASHCHAIN theory (Niksa and Kerstein, 1991; Niksa, 2017). A constitution submodel specifies distributions of molecular weight and reactive sites for native lignin. The model simulates delignification as depolymerization of lignin macromolecules into fragments small enough to be soluble. This process competes with intrachain condensation that consumes labile bridges without forming new fragments, and with recombination that forms larger chains and inhibits further depolymerization. After the soluble fragments are transported from the particle into the bulk solvent, all chemistry continues as long …


Parametric Design Of A Manifold For A Hollow Micropillar Evaporator For Use In High Heat Flux Applications, Alex Dutton Aug 2022

Parametric Design Of A Manifold For A Hollow Micropillar Evaporator For Use In High Heat Flux Applications, Alex Dutton

McKelvey School of Engineering Theses & Dissertations

With the failure of Dennard Scaling and changes in electronics packaging leading toward 2.5 and 3D packages, the current methods of thermal management are failing to keep up with rising heat fluxes. In order to manage these rising heat fluxes, engineers and scientists are looking towards two phase cooling and microchannel flows.

Many forms of novel thermal management are currently being investigated as means to address the thermal challenges present in modern microelectronics, including flow boiling, pool boiling, and direct liquid cooling. One technology of interest is evaporative cooling using continuously fed micro-droplets. High evaporation rates can be achieved by …


Fabrication And Performance Evaluation Of An Evaporative Hollow Micropillar Module For Data Center Cooling Application, Quan Harry Chau Aug 2022

Fabrication And Performance Evaluation Of An Evaporative Hollow Micropillar Module For Data Center Cooling Application, Quan Harry Chau

McKelvey School of Engineering Theses & Dissertations

With the exponential growth of the Internet in the coming decade, data centers will be one of the largest consumers of electricity in many countries. In many data centers, thermal management systems could be just as power-consuming as IT equipment. Chillers in these thermal management systems are one of the highest power components. Microscale evaporation is a promising approach to dissipating high heat fluxes by minimizing thermal resistance between the junction temperature and ambient temperature, hence eliminating the need for chillers. Previous research has shown that droplets elevated by micropillars can limit the vapor diffusion confinement effect, which improves the …


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 …


Nanoscale Interfacial Control Of Ion Behaviors And Caco3 Formation In Environmental Systems, Yaguang Zhu Aug 2022

Nanoscale Interfacial Control Of Ion Behaviors And Caco3 Formation In Environmental Systems, Yaguang Zhu

McKelvey School of Engineering Theses & Dissertations

Interfaces in environmental systems can change the distribution of pollutants and nutrients, determine the fate and transport of nanoparticles, and affect the efficiency of engineering projects. Complex interactions, including electrostatic interactions, Van der Waals interactions, chemical interactions, and ion-surface specific interactions, can all contribute to different ion, ion-pair, and nanoparticle formations near interfaces. Although environmental interfaces play critical roles, only a limited number of studies have considered the nanoscale picture of how they control ions and nanoparticles. Thus, this dissertation addresses three research questions: (1) How does sulfate chemically interact with calcium carbonate (CaCO3) during its heterogeneous formation on quartz …


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 …


Dynamics Of Spatiotemporal Heterogeneities In Particulate Intercalation Electrodes, Shubham Agrawal Aug 2022

Dynamics Of Spatiotemporal Heterogeneities In Particulate Intercalation Electrodes, Shubham Agrawal

McKelvey School of Engineering Theses & Dissertations

Electrochemical energy systems rely on particulate porous electrodes to store or convert energies. While the three-dimensional porous structures of the electrodes were introduced to maximize the interfacial area for better overall performance of the system, spatiotemporal heterogeneities arising from materials thermodynamics localize the charge transfer processes onto a limited portion of the available interfaces. These reaction heterogeneities may cause local hot and cold spots, and early battery failures. This dissertation focuses on the following three aspects of the dynamic reaction heterogeneities in the particulate cathodes and anodes in the lithium-ion batteries: (i) the real-time evolution of reaction heterogeneities in graphite …


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 …


Modeling, Analysis, And Simulation To Reveal The Mechanisms Of Ciliary Beating, Louis Woodhams Aug 2022

Modeling, Analysis, And Simulation To Reveal The Mechanisms Of Ciliary Beating, Louis Woodhams

McKelvey School of Engineering Theses & Dissertations

Cilia are microscopic cellular appendages that help us breathe by clearing our airways, maintain the health of our central nervous system by circulating cerebrospinal fluid, and allow us to reproduce by transporting eggs and propelling sperm cells. Cilia even determine the asymmetry of our internal organs during embryonic development. However, the mechanisms underlying ciliary beating are not fully understood. Questions remain as to how arrays of the motor protein dynein generate the propulsive waveforms observed in cilia and how structural elements within the cilium and its connection to the cell deform during beating. In the current work, mathematical modeling, analysis, …


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 …


Synthesis And Consolidation Of Metal Oxide Nanocrystals Via Nonthermal Plasma, Austin Cendejas Aug 2022

Synthesis And Consolidation Of Metal Oxide Nanocrystals Via Nonthermal Plasma, Austin Cendejas

McKelvey School of Engineering Theses & Dissertations

Nonthermal plasmas offer a unique nonequilibrium environment that has been leveraged in a wide variety of applications in the fields of material processing, lighting, and waste management to name a few. In all of these cases, the plasma serves as a source of high energy electrons, ions, reactive gas species, and radicals that interact in several ways with surfaces brought into contact with the plasma. Specifically, nonthermal plasmas have been shown to be very successful in achieving continuous, high-throughput, monodisperse nanocrystals of a wide variety of materials. The crystallinity of nanoparticles synthesized in nonthermal plasmas can be attributed to the …


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. …