Engineering Commons^™

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

McKelvey School of Engineering Graduate Student 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 …

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

McKelvey School of Engineering Graduate Student 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 …

Modeling The Effects Of Mechanical Loading On Hypertrophic Cardiomyopathy Pathogenesis In Human Induced Pluripotent Stem Cell Derived Micro Heart Muscle, Jingxuan Guo

McKelvey School of Engineering Graduate Student Theses & Dissertations

Sudden cardiac death in the young is devastating. Advances in genetics have associated mutations in the contractile sarcomere apparatus of cardiomyocytes with hypertrophic cardiomyopathy, the most frequent cause of sudden cardiac death in the young. Currently, it is challenging to predict genotype-phenotype relationships in hypertrophic cardiomyopathy due to its incomplete disease penetrance. For example, different patients from the same family with identical genomic variants develop different symptoms. Non-genetic, environmental factors such as blood pressure are critical in heart function and disease. Therefore, understanding how mechanical factors contribute to phenotypes in diseases like hypertrophic cardiomyopathy is critical for developing effective therapeutics. …

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

McKelvey School of Engineering Graduate Student 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 …

Droplet-Based Two-Phase Thermal Management, Junhui Li

McKelvey School of Engineering Graduate Student Theses & Dissertations

The rapid development of electronic systems with ever-higher power densities in a wide range of applications requires new advanced thermal management methods. Droplet-based two-phase thermal management technologies are considered promising solutions to conquer the cooling challenges in the electronic industries. The heat transfer behavior of droplets is based on several important fundamental processes, such as droplet evaporation, droplet impact on heated surfaces, and molten droplet impact. In this dissertation, four research projects are completed to explore the insights of these fundamental processes. For droplet evaporation, I introduce an investigation of diffusion confinement of droplets evaporating on a supported pillar structure. …

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 Graduate Student 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 …

Fate Of Metals In Presence Of Minerals And Mineral-Organic Assemblages, Neha Sharma

McKelvey School of Engineering Graduate Student Theses & Dissertations

Metals can enter aquatic systems from natural and anthropogenic processes associated with weathering, sediment re-suspension, industrial activities, and atmospheric deposition. Metals pose health and environmental risks at high concentrations due to their potential toxicity and bioaccumulation, but many trace metals also serve as essential micronutrients for biogeochemical processes in natural aquatic systems. Biogeochemical processes such as methanogenesis, denitrification, and mercury methylation require transition metals such as nickel (Ni), cobalt (Co), copper (Cu), and molybdenum (Mo) for completion. These biogeochemical processes can be substantial contributors of greenhouse gases, such as methane (CH4) and nitrous oxide (N2O), into the atmosphere. The behavior, …

Noninvasive Neuromodulation Via Ultrasonic Activation Of Endogenous And Exogenous Ion Channels, Yaoheng Yang

McKelvey School of Engineering Graduate Student Theses & Dissertations

Neuromodulation technology is key to understanding brain function and treating brain diseases. Conventional neuromodulation technologies, such as direct current stimulation, transcranial magnetic stimulation, and optogenetics, predominately rely on electromagnetic waves. However, the fundamental physical law  the tradeoff-relationship between penetration and spatial resolution, limits their transcranial penetration within the superficial cortex layer. To overcome this challenge, electrodes or optical fibers need to be surgically implanted into the brain to modulate specific brain regions. Different from electromagnetic waves, ultrasound, as a mechanical wave, can non-invasively penetrate through the intact skull to reach deep brain regions with millimeter spatial focus. Ultrasound has …

Design Of Multi-Principal Element Materials Using A Combination Of First-Principles Calculations And Machine Learning, Zhaohan Zhang

McKelvey School of Engineering Graduate Student Theses & Dissertations

Multiple-principal element materials, including alloys (MPEAs), oxides and other compounds combine several elements on a sub-lattice, which increases the configurational entropy and contributes to their thermodynamic stability. The vast combinatorial design space of multi-principal element materials gives rise to diverse microstructures and unprecedent combination of properties. It also poses a challenge—how to rapidly screen MPEAs with stability and properties for targeted applications. Furthermore, fundamental composition-structure-property relationships in MPEAs are currently missing. In this dissertation, I have used MPEAs as a representative system and investigated the role of chemical composition on their phase-stability and mechanical properties. With a combination of first-principles …

Advanced Nanomaterials And Module Designs For Efficient Photothermal Water Treatment, Deoukchen Ghim

McKelvey School of Engineering Graduate Student Theses & Dissertations

Water scarcity is one of the most serious challenges that human beings face, and the demand for clean water will continuously increase as populations grow. Creating potable water from saline water is an important way to meet global freshwater demands. However, current desalination techniques require high energy consumption and a large scale to be efficient, restricting their utilization in remote and underdeveloped areas. These constraints motivate the development of sustainable water treatment methods that can be used with less energy input, in small modular configurations, and in off-grid water treatment systems. As an abundant and renewable energy source, sunlight has …

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

McKelvey School of Engineering Graduate Student 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 …

Droplet Dynamics And Heat Transfer During Condensation On Lubricant-Infused Surfaces, Jianxing Sun

McKelvey School of Engineering Graduate Student Theses & Dissertations

Inspired by pitcher plants, a micro/nano- structured solid surface infused with low-surface-tension lubricant constitutes a novel class of biomimetic surfaces—lubricant-infused surfaces (LISs). Unlike solid hydrophobic and superhydrophobic surfaces, a LIS is “hemi-solid and hemi-liquid”. The thin lubricating film can extraordinarily decrease adhesion and avoid contact line pinning between the working fluid and the underlying solid, displaying many desirable properties, such as excellent liquid repellency, suppression of fouling, and self-healing. Hence, LISs are ideal for applications where liquids or contaminants must be efficiently removed from surfaces in harsh environments. For example, LISs can promote stable dropwise condensation of water or low-surface-tension …

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

McKelvey School of Engineering Graduate Student 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, …

Pet/Mr Imaging Biomarkers For Cerebral Small Vascular Diseases: Tissue Oxygenation Stress And Neuroinflammation, Chunwei Ying

McKelvey School of Engineering Graduate Student Theses & Dissertations

Fifty million people are affected by dementia worldwide. Cerebral small vessel disease (CSVD) often leads to vascular contributions to cognitive impairment and dementia (VCID), the second leading cause of dementia after Alzheimer’s disease (AD), accounting for up to 45% of dementia. White matter hyperintensities (WMH) on fluid-attenuated inversion recovery (FLAIR) imaging and disrupted white matter microstructure on diffusion tensor imaging (DTI) have been widely used as biomarkers to evaluate CSVD.

The pathogenesis underlying CSVD is not well understood. It has been postulated that exposure to risk factors, including hypertension, diabetes, and smoking over years injures small arterioles, impairs autoregulation and …

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

McKelvey School of Engineering Graduate Student 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 …

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

McKelvey School of Engineering Graduate Student 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 …

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

McKelvey School of Engineering Graduate Student 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 …

Lead(Iv) Oxide In Drinking Water Systems: Formation, Dissolution, Redox-Driven Recrystallization, And Implications For Lead Control, Weiyi Pan

McKelvey School of Engineering Graduate Student Theses & Dissertations

Lead (Pb) in tap water is mainly contributed by lead service lines (LSLs). The dissolved lead concentration is controlled by the solubilities of lead corrosion products that form on the inner surface of LSLs. Among these lead corrosion products, lead(IV) oxide (PbO2) has the lowest solubility and can maintain a low lead level when free chlorine is present. Current strategies to control the lead concentration include replacing the LSL, optimizing the water chemistry conditions, and using point-of-use (POU) filters. The present study investigated the effect of manganese (Mn) on the oxidation of the lead(II) carbonate solids by free chlorine, the …

The Generation And Transport Of Charged Aerosols: Fundamental Study And Applications In Medicine And Energy Conversion, Hao Zhou

McKelvey School of Engineering Graduate Student Theses & Dissertations

Charged aerosols have significant implications in the field of functional material synthesis, pharmaceutical coating, and drug delivery. Electrospray systems are an effective methodology for generating highly charged monodispersed droplets in the size range from nanometer to micrometer. The prediction of surface charge, size and morphology of nanoparticles resulting from charged droplets are highly required for the precise control of nanoparticle properties and their effective utilization. However, the evolution of charged droplet is not well understood due to the existence of coulombic fission and ion evaporation processes. Thus, the goal of this dissertation is to elucidate how the precursor properties and …

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

McKelvey School of Engineering Graduate Student 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 …

Role Of Water Chemistry In Lead Release During Drinking Water Supply And Augmentation, Anushka Mishrra

McKelvey School of Engineering Graduate Student Theses & Dissertations

Lead is a toxic heavy metal and legacy contaminant in drinking water that can be released from lead service lines and lead-containing premise plumbing. Lead concentrations in water are sensitive to changes in water chemistry. The extent of lead release is often driven by the solubility of the corrosion products formed on the interior of the pipes. Therefore, it is critical to advance our understanding of the extent of lead released from different lead-based plumbing materials at equilibrium and the ability to control lead when it exceeds the regulatory levels. Lead measured in the 1st liter of water collected from …

Soft Electronics And Sensors For Wearable Healthcare Applications, Li-Wei Lo

McKelvey School of Engineering Graduate Student Theses & Dissertations

Wearable electronics are becoming increasingly essential to personalized medicine by collecting and analyzing massive amounts of biological signals from internal organs, muscles, and blood vessels. Conventional rigid electronics may lead to motion artifacts and errors in collected data due to the mismatches in mechanical properties between human skin. Instead, soft wearable electronics provide a better platform and interface that can form intimate contact and conformably adapt to human skin. In this respect, this thesis focuses on new materials formulation, fabrication, characterization of low-cost, high sensitivity and reliable sensors for wearable health monitoring applications.

More specifically, we have studied the silver …

Dynamics Of Spatiotemporal Heterogeneities In Particulate Intercalation Electrodes, Shubham Agrawal

McKelvey School of Engineering Graduate Student 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 …

Photochemical Formation Mechanisms And Applications Of Mn Oxide Nanomaterials, Zhenwei Gao

McKelvey School of Engineering Graduate Student Theses & Dissertations

Manganese (Mn) oxides are ubiquitous in aquatic and terrestrial environments, and the rich redox chemistry of manganese is of interest in engineered systems, such as batteries and water oxidation catalysts. Mn oxides have large surface areas and are highly active in adsorption and redox reactions. Our research group recently reported photochemically-assisted abiotic inorganic oxidation of Mn2+(aq) to δ-MnO2 nanosheets in the presence of nitrate and without a microorganism, demonstrating that abiotic Mn oxidation processes are not negligible. My doctoral work focuses on investigating the effects of various aquatic chemistry parameters, including reactive oxygen species (ROS), peroxyl radical (ROO•), reactive halogen …

Development Of Noninvasive Biomarkers For Cervical Spondylotic Myelopathy, Dinal Jayasekera

McKelvey School of Engineering Graduate Student 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. …

Advancing The Portability, Field Of View, And Spatiotemporal Resolution Of Multi-Parametric Photoacoustic Microscopy, Fenghe Zhong

McKelvey School of Engineering Graduate Student Theses & Dissertations

Capable of structural, functional, molecular, and metabolic imaging with high spatial resolution in vivo, photoacoustic microscopy (PAM) is an emerging tool in biomedical research. Further, recent advances in multi-parametric acquisition and analysis make PAM uniquely capable of simultaneously mapping the total concentration of hemoglobin (CHb), oxygen saturation of hemoglobin (sO2), and blood flow speed. However, there are multiple major limitations, including, the large footprint, low imaging speed, limited imaging contrast, and insufficient axial resolution, which impedance its applications in basic and translational research. In this dissertation, I presented potential solutions to overcome the limitations above.In the first part of this …

Model-Based Deep Learning For Computational Imaging, Xiaojian Xu

McKelvey School of Engineering Graduate Student Theses & Dissertations

This dissertation addresses model-based deep learning for computational imaging. The motivation of our work is driven by the increasing interests in the combination of imaging model, which provides data-consistency guarantees to the observed measurements, and deep learning, which provides advanced prior modeling driven by data. Following this idea, we develop multiple algorithms by integrating the classical model-based optimization and modern deep learning to enable efficient and reliable imaging. We demonstrate the performance of our algorithms by validating their performance on various imaging applications and providing rigorous theoretical analysis.

The dissertation evaluates and extends three general frameworks, plug-and-play priors (PnP), regularized …

Nano-Bio Interactions: Implications And Applications, Anushree Ghosh

McKelvey School of Engineering Graduate Student Theses & Dissertations

Rapid expansion of technology development at the nanoscale has underpinned a promising industry. Towards this, there remain significant information gaps which are critical with regard to decision making processes and ultimate industrial sustainability. From an implication point of view, understanding how common biological macromolecules, including glycolipids and/or biopolymers produced by bacteria and fungi, which are ubiquitous in the environment, is fundamental to predicting the behavior of released/produced nanoparticles. Conversely, other bio-based tailored macromolecules, including mussel foot protein (MFP), have significant potential as functional material coatings for advanced applications.This PhD thesis is focused on interfacial processes related to superparamagnetic iron oxide …

Calcium Bearing Mineral-Hydrogel Composites For Phosphate Removal And Recovery, Albern Xuan-Wei Tan

McKelvey School of Engineering Graduate Student Theses & Dissertations

The millions of tons of phosphate rock ore mined every year for use as phosphorus fertilizer have created two challenges. First, phosphate rock is a mined, non-renewable resource that is also heavily geographically concentrated, raising concerns about the long-term sustainability and availability of phosphorus. Second, after it is applied as a fertilizer, phosphorus will also be released to the broader environment. There, it contributes to harmful algal blooms and eutrophication, which threaten surface water quality and can harm aquatic ecosystems and the communities and industries that rely on them. These considerations motivate the coupled development of techniques for removing and …

Understanding Control Of Metabolite Dynamics And Heterogeneity, Christopher John Hartline

McKelvey School of Engineering Graduate Student 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 …