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Articles 271 - 300 of 3436

Full-Text Articles in Physical Sciences and Mathematics

Detailed Characterization Of Material Deformation, Alexander J. Farnsworth Aug 2023

Detailed Characterization Of Material Deformation, Alexander J. Farnsworth

Theses and Dissertations

This dissertation presents a comprehensive exploration of material deformation at the atomic level, investigating key findings and contributions through three fundamental methods: Sum Frequency Generation Spectroscopy (SFG), X-ray Diffraction (XRD), and Electron Backscatter Diffraction (EBSD). The research commences by uncovering the material dependency of nonresonant responses in both SFG and Second Harmonic Generation (SHG) signals. This redefinition of the nonresonant component as an information-rich carrier, rather than mere background noise, leads to novel insights into the potential applications of SFG. The study then delves further into the influence of mechanical stress on materials, establishing a connection between dislocation density on …

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Separation Of Perrhenate And Perfluoroalkyl Substances By Ion Chromatography With Customized Stationary Phases, Wai Ning Chan Aug 2023

Separation Of Perrhenate And Perfluoroalkyl Substances By Ion Chromatography With Customized Stationary Phases, Wai Ning Chan

Theses and Dissertations

Ion exchange chromatography (IC) is an analytical technique used to separate charged molecules including ions, proteins, small nucleotides, and amino acids. It can function in anion or cation mode. In this dissertation, anion exchange chromatography was used, and column materials were made in our lab with resorcinarene-based compounds called cavitands. Cavitands create cavities to bind to molecules because of their three-dimensional structure. Two new gradient IC methods were established to identify and quantify perrhenate and perfluoroalkyl substances (PFAS) by customized resorcinarene-based column, zinc cyclen resoecinarene (ZCR) and arginine methyl ester (RUE) columns. The ZCR column accomplished outstanding separation of perrhenate …

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The Role Of Cytosolic Chaperonin Cct And Its Co-Chaperone Phlp1 In Folding And Assembly Of Signaling Complexes, Yujin Kwon Aug 2023

The Role Of Cytosolic Chaperonin Cct And Its Co-Chaperone Phlp1 In Folding And Assembly Of Signaling Complexes, Yujin Kwon

Theses and Dissertations

CCT, a large (1 MDa) protein-folding machine, is a eukaryotic group II chaperonin that is essential for folding many cellular proteins and is the most complex of all chaperonins with two rings each composed of eight paralogous subunits. CCT captures proteins in its folding chamber to assist the folding of its substrates. CCT utilizes ATP hydrolysis to open and close its chamber and fold its substrates. CCT has been shown to be important in the folding of proteins with - propeller domains which consist of seven WD40 repeat sequences that fold into -sheets that form the blades of a propeller-like …

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Rural Science Teachers Social Network Analysis Matrices, Rebecca L. Sansom, Tracy Poulsen Aug 2023

Rural Science Teachers Social Network Analysis Matrices, Rebecca L. Sansom, Tracy Poulsen

ScholarsArchive Data

These are the social network matrices for our study of rural science teachers. Each matrix is located on a separate tab on the spreadsheet.

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Terahertz From Electrons, Electronics From Terahertz, Clayton D. Moss Aug 2023

Terahertz From Electrons, Electronics From Terahertz, Clayton D. Moss

Theses and Dissertations

Time-domain terahertz spectroscopy (THz-TDS) is a valuable technique for studying collective ultrafast phenomena. Several mechanisms exist for converting ultrashort optical laser pulses into coherent THz sources. Broadband THz pulses can be obtained from electron currents in air plasma, which requires combinations of different colors of light to be most effective. I report multi-color generation schemes of THz pulses that deliver coherent THz output. Experimental and theoretical work using the photocurrent model describe ways to use non-harmonic color combinations to utilize several sources of light available in a table-top laser setup. Additionally, THz-TDS is used to study a variety of ultrafast …

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The Influence Of Political Media On Large Language Models: Impacts On Information Synthesis, Reasoning, And Demographic Representation, Alexander Glenn Shaw Aug 2023

The Influence Of Political Media On Large Language Models: Impacts On Information Synthesis, Reasoning, And Demographic Representation, Alexander Glenn Shaw

Theses and Dissertations

This thesis investigates the impact of finetuning the LLaMA 33B language model on partisan news datasets, revealing negligible changes and underscoring the enduring influence of pretraining datasets on model opinions. Training nine models across nine distinct news datasets spanning three topics and two ideologies, the study found consistent demographic representation, predominantly favoring liberal, college-educated, high-income, and non-religious demographics. Interestingly, a depolarizing effect emerged from partisan news finetuning, suggesting that intense exposure to topic-specific information might lead to depolarization, irrespective of ideological alignment. Despite the exposure to contrasting viewpoints, LLaMA 33B maintained its common sense reasoning ability, showing minimal variance on …

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Improved Endmember Mixing Analysis (Emma): Application To A Nested Catchment, Provo River, Northern Utah, Alyssa Nicole Thompson Aug 2023

Improved Endmember Mixing Analysis (Emma): Application To A Nested Catchment, Provo River, Northern Utah, Alyssa Nicole Thompson

Theses and Dissertations

An endmember mixing analysis (EMMA) is a hydrograph separation technique used to identify and quantify stream source contributions, but the error within the results of the analysis itself can be difficult to quantify. Employing EMMA to accurately quantify these contributions is particularly important for critical watersheds that supply water to large populations, such as montane watersheds. We applied EMMA to the Provo River, a nested catchment with three monitoring locations in northern Utah, to understand the limitations and potential improvements that could be made to EMMA. Four main endmembers (quartzite groundwater, soil water, snow and carbonate groundwater) were identified for …

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Semantically Structured Creative Computer Systems & Automated Evaluation Of Creative Artifacts, Brad Spendlove Aug 2023

Semantically Structured Creative Computer Systems & Automated Evaluation Of Creative Artifacts, Brad Spendlove

Theses and Dissertations

Computational creativity seeks, in part, to develop autonomous agents that exhibit creativity. Language is an ideal creative domain for studying computer agents due to its rich interconnectedness and immense space of possible combinations. This dissertation explores the design, testing, and theory of creative computer systems that write microfiction and play the board game Codenames. The designs of these systems are all similarly based on building up creative artifacts from the underlying structure of the relationships between words. A critical component of the creative process is the ability to evaluate the quality of creative output. Human and automated assessment of our …

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Geochemistry Of Zircon And Apatite In Rhyolites From The Central Snake River Plain: Genetic Implications, Chesley Philip Gale Aug 2023

Geochemistry Of Zircon And Apatite In Rhyolites From The Central Snake River Plain: Genetic Implications, Chesley Philip Gale

Theses and Dissertations

Whole-rock and mineral compositions of three eruptive deposits from the Twin Falls caldera, associated with the Yellowstone hotspot, provide a window into melt generation and evolution for hot, dry, A-type rhyolites. Three rhyolitic units were sampled via the Kimberly drill-core as a part of project HOTSPOT, a study focused on mantle plume and continental lithosphere interaction. Previous work has been done to collect high resolution U-Pb zircon ages, and Hf- and O-isotopic compositions. This study examined the geochemistry of apatite and zircon along with host rock compositions in the context of this previous work. The Kimberly core sampled the Shoshone …

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Groundwater Flow Across The Coyote Wash Fault And Cedar Mesa Anticline Near St. Johns, Arizona, Stephanie Lynn Latour Aug 2023

Groundwater Flow Across The Coyote Wash Fault And Cedar Mesa Anticline Near St. Johns, Arizona, Stephanie Lynn Latour

Theses and Dissertations

As the demand for water increases across the southwestern United States, the region's utilization of and dependence on water stored in groundwater aquifers has risen in kind. The Coconino Aquifer (C-aquifer) underlies much of the southwestern Colorado Plateau and is a primary source of groundwater in northeastern Arizona. One of the largest commercial users of water from the C-aquifer in Apache County, Arizona, is Springerville Generating Station, a coal-fired power plant owned and operated by Tucson Electric Power. The area surrounding the power plant, located between the cities of Springerville and St. Johns, Arizona (the Springerville-St. Johns area), is geologically …

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The Student Becomes The Teacher: Training High-Performance Language Models More Sample-Efficiently From Small Models Via Superstilling, Chaz Allen Gundry Aug 2023

The Student Becomes The Teacher: Training High-Performance Language Models More Sample-Efficiently From Small Models Via Superstilling, Chaz Allen Gundry

Theses and Dissertations

Recent advances including the Transformer architecture have revolutionized the Natural Language Processing community by providing immense performance improvements across many tasks, including the development of Large Language Models (LLMs). LLMs show enormous promise as few-shot learners, common-sense knowledge repositories, conversational agents, writing assistants, and coding tools, and are gaining widespread traction in commercial industry. However, LLMs are expensive and time-consuming to train, requiring many passes over terabytes of data for the largest models. In this paper, we present Superstilling, a method for reducing the sample complexity of language model training by distilling the knowledge from a previously-trained model (the teacher) …

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Exploring New Horizons In Microwave-Promoted Iminyl Radical Chemistry And Synthesis Of Bulky Dehydroamino Acids, Jatinder Singh Aug 2023

Exploring New Horizons In Microwave-Promoted Iminyl Radical Chemistry And Synthesis Of Bulky Dehydroamino Acids, Jatinder Singh

Theses and Dissertations

The first project in this dissertation presents a simplified and efficient protocol for synthesizing pyrrolines through 5-exo iminyl radical cyclizations. The microwave irradiation of O-Phenyloximes tethered to alkenes causes N-O homolysis resulting in iminyl radical generation, which subsequently undergoes 5-exo-trig cyclizations furnishing pyrrolines. This eliminates the need for toxic radical initiators (AIBN, benzoyl peroxide), propagating agents (Bu3SnH, (Me3Si)3SiH), and expensive catalysts or single-electron transfer (SET) cycles. We explored the scope of diverse traps and substrates for iminyl radical cyclizations. The iminyl radical cyclizations formed versatile pyrrolines with moderate to excellent yields. The diastereoselectivity also ranged from low to high. Moreover, …

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Improving Xrd Analysis With Machine Learning, Rachel E. Drapeau Aug 2023

Improving Xrd Analysis With Machine Learning, Rachel E. Drapeau

Theses and Dissertations

X-ray diffraction analysis (XRD) is an inexpensive method to quantify the relative proportions of mineral phases in a rock or soil sample. However, the analytical software available for XRD requires extensive user input to choose phases to include in the analysis. Consequently, analysis accuracy depends greatly on the experience of the analyst, especially as the number of phases in a sample increases (Raven & Self, 2017; Omotoso, 2006). The purpose of this project is to test whether incorporating machine learning methods into XRD software can improve the accuracy of analyses by assisting in the phase-picking process. In order to provide …

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Engagement In Secondary Mathematics Group Work: A Student Perspective, Rachel H. Jorgenson Aug 2023

Engagement In Secondary Mathematics Group Work: A Student Perspective, Rachel H. Jorgenson

Theses and Dissertations

In the realm of academic engagement research, students are valuable sources of information to learn how and why students often engage unproductively in mathematics group work. However, although secondary mathematics students are often expected to engage in meaningful mathematical discourse in a small group setting, little research has been conducted to better understand student engagement in this setting from the perspective of the students themselves. This thesis attempts to understand how one junior high student described his own engagement in mathematics small group work as well as what factors influenced this engagement. By conducting several cycles of observations and interviews …

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Parents' Perceptions Of The Importance Of Teaching Mathematics: A Q-Study, Ashlynn M. Holley Aug 2023

Parents' Perceptions Of The Importance Of Teaching Mathematics: A Q-Study, Ashlynn M. Holley

Theses and Dissertations

Mathematics education has gone through multiple reform efforts over the last century and continues to be the target of improvement efforts. Past changes in curriculum and goals have sometimes led to heated debates between various stakeholders. Knowing the views of different stakeholders can help determine what common ground there is between these different groups and where areas of disagreement might arise. Parents are especially important to understand because they have been influential in past reform efforts. Despite the importance of parents' opinions, little research has been conducted concerning their perspectives on the importance of mathematics teaching. Using Q-methodology, I was …

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Physics-Guided Modeling Of Acoustic Environments Using Limited Spatio-Spectro-Temporal Data, Mylan Ray Cook Aug 2023

Physics-Guided Modeling Of Acoustic Environments Using Limited Spatio-Spectro-Temporal Data, Mylan Ray Cook

Theses and Dissertations

When creating data-based models it is important to include the underlying physical characteristics and constraints of the data. If physical characteristics are not properly included in the model, results may be infeasible or physically impossible. Acoustic environments are better characterized by ensuring that models include the fundamental spatial, spectral, and temporal characteristics of noise sources, or how they change based on location, frequency, and time. When model data are limited, in availability or in reliability, additional care must be taken to ensure models predict feasible results. This dissertation focuses on physics-guided modeling of acoustic environments using limited data, taking into …

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A Step Into Structural Biology: Structural Determination Of Tnk1-Uba And Computational Design Of A Radical Sam Cyclase, Yi-Jie Tseng Aug 2023

A Step Into Structural Biology: Structural Determination Of Tnk1-Uba And Computational Design Of A Radical Sam Cyclase, Yi-Jie Tseng

Theses and Dissertations

Structural biology uncovers life's secrets by studying protein structures via techniques like X-ray crystallography. This knowledge drives advancements in protein engineering for the improvement of human lives. Yet, obtaining high-quality crystals in X-ray crystallography is challenging. To overcome this, we used Translocation ETS Leukemia protein Sterile Alpha Motif domain (TELSAM), a promising polymer-forming crystallization chaperone (PFCC), to enhance protein crystallization. Human thirty-eight-negative kinase-1 (TNK1), a key player in cancer progression, possess a ubiquitin association (UBA) domain that binds polyubiquitin and regulates TNK1 activity and stability. Although sequence analysis hints at an unconventional TNK1 UBA domain architecture, its molecular structure lacks …

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Computational Modeling Of Energy Landscapes And Trajectory Studies Of Fundamental Organometallic Reactions, Joshua I. Wheeler Aug 2023

Computational Modeling Of Energy Landscapes And Trajectory Studies Of Fundamental Organometallic Reactions, Joshua I. Wheeler

Theses and Dissertations

Organometallic reactions are a fundamental class of chemical transformations. The mechanisms of organometallic reactions are routinely modeled by calculating intermediates and transition-state structures on a potential energy surface with density functional theory (DFT). The translation of these calculated structures to a reaction mechanism is typically done under the umbrella of statistical transition state theory. This dissertation reports the use of DFT calculations and quasiclassical direct dynamics trajectories to explore the possibility of nonstatistical dynamic effects in organometallic reactions. Chapter 1 provides a brief review of potential energy surfaces, transition state theory, dynamics trajectories, and a review of previous dynamics studies …

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More Is Better Than One: The Effect Of Ensembling On Deep Learning Performance In Biochemical Prediction Problems, Jacob A. Stern Aug 2023

More Is Better Than One: The Effect Of Ensembling On Deep Learning Performance In Biochemical Prediction Problems, Jacob A. Stern

Theses and Dissertations

This thesis presents two papers addressing important biochemical prediction challenges. The first paper focuses on accurate protein distance predictions and introduces updates to the ProSPr network. We evaluate its performance in the Critical Assessment of techniques for Protein Structure Prediction (CASP14) competition, investigating its accuracy dependence on sequence length and multiple sequence alignment depth. The ProSPr network, an ensemble of three convolutional neural networks (CNNs), demonstrates superior performance compared to individual networks. The second paper addresses the issue of accurate ligand ranking in virtual screening for drug discovery. We propose MILCDock, a machine learning consensus docking tool that leverages predictions …

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What's The Password? Account Sharing In The Context Of Passwordless Authentication, Daniel Taylor Aug 2023

What's The Password? Account Sharing In The Context Of Passwordless Authentication, Daniel Taylor

Undergraduate Honors Theses

Passwordless authentication methods are becoming increasingly available for online accounts. This research asks how people will share online accounts with friends and family when there is no longer a password to share. Research participants were introduced to passwordless authentication methods and asked how they imagine the account sharing process might work. They were then introduced to four different methods of passwordless accounts, and asked to evaluate them. Sharing a link to register an additional authentication method proved to be the most popular method of account sharing.

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Cloning A Fusion Gene For The Identification Of The Proteins Contained In Ubiquitin-Rich Condensates, Grace M. Whitehead Aug 2023

Cloning A Fusion Gene For The Identification Of The Proteins Contained In Ubiquitin-Rich Condensates, Grace M. Whitehead

Undergraduate Honors Theses

Cellular liquid-liquid phase separation (LLPS) is a mechanism by which membraneless organelles such as polyubiquitinated condensates form and function. A non-receptor tyrosine kinase, Tnk1, binds to the polyubiquitin of polyubiquitinated condensates that are labeled for the proteasome for autophagy through its ubiquitin association (UBA) domain. This tyrosine kinase has links to a subset of hematological cancers, so identifying the protein contents within polyubiquitinated condensates is essential for understanding their significance in cancer pathways and to eventually identify potential therapeutic targets. This honors thesis focuses on the cloning of a fusion gene, pcDNA3.1 mNeonGreen–V5–UBA, as well as its deactivated L36D variant, …

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Practicing Mathematics Teachers' Perspectives Of Public Records In Their Classrooms, Sini Nicole White Graff Jul 2023

Practicing Mathematics Teachers' Perspectives Of Public Records In Their Classrooms, Sini Nicole White Graff

Theses and Dissertations

While media displays exist in every mathematics classroom, these displays may have been taken for granted by teachers and researchers in terms of their potential use and impact on learning. This study looks at how three practicing mathematics teachers with differing teaching styles and experience levels view and use these media displays in their classrooms. This research shows how the relationship between a teachers' perceptions of media displays for showing mathematics are closely tied to their own beliefs regarding teaching and learning. Findings for this study can provide researchers with a starting place to see how teachers perceive and talk …

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Ally Mediation Of Social Media Use For Adults With Autism, Spring S. Cullen Jun 2023

Ally Mediation Of Social Media Use For Adults With Autism, Spring S. Cullen

Theses and Dissertations

Previous research has highlighted the unique challenges young Autistic adults face when using social media. We extend this work by analyzing how guardians and allies, such as service providers, mediate the social media usage of young Autistic adults in order to address and mitigate online risks. Based on analysis of interview transcripts (8 young adults on the Autism spectrum, 4 parents, 10 staff members), we uncover the mediation tactics used, how they differ based on the ally's relationship with the individual, and the tactics' varying degrees of effectiveness. The findings of this research contribute to the literature by informing the …

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Extending Model Checking Using Inductive Proofs In Distributed Digital Currency Protocols, Kyle R. Storey Jun 2023

Extending Model Checking Using Inductive Proofs In Distributed Digital Currency Protocols, Kyle R. Storey

Theses and Dissertations

Model checking is an effective method to verify both safety and liveness properties in distributed systems. However, the complexity of model checking grows exponentially with the number of entities which makes it suitable only for small systems. Interactive theorem provers allow for machine-checked proofs. These proofs can include inductive reasoning which allows them to reason about an arbitrarily large number of entities. However, proving safety and liveness properties in these proofs can be difficult. This work explores how combining model checking and inductive proofs can be an effective method for formally verifying complex distributed protocols. This is demonstrated on a …

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Characterizing Dust From National Wind Erosion Research Network Sites Using Strontium Isotopes, Major And Trace Element Chemistry, And Mineralogy, Abby L. Mangum Jun 2023

Characterizing Dust From National Wind Erosion Research Network Sites Using Strontium Isotopes, Major And Trace Element Chemistry, And Mineralogy, Abby L. Mangum

Theses and Dissertations

The frequency of dust storms is increasing globally yet it is often difficult to determine dust sources in mixed events. Dust events may negatively impact human health, but the composition of major dust sources is not well characterized in arid regions globally. In the western US, the National Wind Erosion Research Network (NWERN) has various sites evaluating seasonal dust emissions to quantify dust fluxes. We used existing dust samples to characterize the isotopic, chemical, and mineralogical composition of dust over multiple seasons from ten representative NWERN sites and compared with land use, vegetation, and surficial geology. Our results show variability …

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Acoustic Directivity: Advances In Acoustic Center Localization, Measurement Optimization, Directional Modeling, And Sound Power Spectral Estimation, Samuel David Bellows Jun 2023

Acoustic Directivity: Advances In Acoustic Center Localization, Measurement Optimization, Directional Modeling, And Sound Power Spectral Estimation, Samuel David Bellows

Theses and Dissertations

Sound radiation from an acoustic source typically exhibits directional behavior, as is the case for the human voice, musical instruments, and loudspeakers, to name just a few. The necessity of directional data for many applications, such as sound source modeling, microphone placement, room acoustical design, and auralization, motivates directivity measurements. However, these measurements require careful understanding and implementation to produce the most meaningful results. Accordingly, this dissertation addresses several topics relevant to directivity theory, measurement, processing, and application. It first expands and amends previously published concepts of an acoustic source center and demonstrates the close relationship between the center and …

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Ultracold Neutral Plasma Evolution In An External Magnetic Field, Chanhyun Pak Jun 2023

Ultracold Neutral Plasma Evolution In An External Magnetic Field, Chanhyun Pak

Theses and Dissertations

We study the expansion velocity and ion temperature evolution of ultracold neutral plasmas (UNPs) of calcium atoms under the influence of a uniform magnetic field that ranges up to 200 G. In the experiments, we use a magneto-optical trap (MOT) to capture the neutral atoms and laser-induced fluorescence (LIF) to take images of the plasma. We vary the magnetic field strengths and the initial electron temperatures and observe the plasma evolution in time. We compare the ion temperature evolution to the theory introduced in the paper by Pohl et. al. [Phys. Rev. A 70, 033416 (2004)]. The evolution of the …

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Reconstructing Historical Earthquake-Induced Tsunamis: Case Study Of 1852 Event Using The Adjoint Method Combined With Hmc, Chelsey Noorda Jun 2023

Reconstructing Historical Earthquake-Induced Tsunamis: Case Study Of 1852 Event Using The Adjoint Method Combined With Hmc, Chelsey Noorda

Theses and Dissertations

Seismic hazard analysis aims to estimate human risk due to natural disasters such as earthquakes. To improve seismic hazard analysis, our group is focused on earthquake induced tsunamis and the use of statistical models to reconstruct historical earthquakes. Based on the estimated wave heights given in anecdotal historical descriptions, we created observational probability distributions to model the historically recorded observations and constructed a prior distribution on the relevant earthquake parameters based on known seismicity of a given region. Then we used the software package GeoClaw, and a Metropolis-Hastings sampler to obtain a posterior distribution of earthquake parameters that most closely …

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Developing Microfluidic Devices For Biomolecule Analysis, Jacob Brent Nielsen Jun 2023

Developing Microfluidic Devices For Biomolecule Analysis, Jacob Brent Nielsen

Theses and Dissertations

Microfluidics can take laboratory processes and miniaturize them, which led to the term lab-on-a-chip. Microfluidic devices are fabricated with a variety of materials and methods, each offering distinct advantages for bioanalysis. This dissertation describes two methods to create these devices, with the use of four different materials to achieve different assay needs. In the first application in this dissertation, hot-embossed cyclic olefin copolymer was used to create microdevices to electrophoretically separate seven preterm birth biomarkers. One biomarker, thrombin-antithrombin III, cannot be purchased commercially so I developed methods for its assembly in the lab. Dot blots and mass spectrometry were used …

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Context Dependence Of Non-Covalent Interactions Among Amino-Acid Side Chains Along The Solvent-Exposed Surface Of Coiled Coils, Kimberlee Larsen Stern Jun 2023

Context Dependence Of Non-Covalent Interactions Among Amino-Acid Side Chains Along The Solvent-Exposed Surface Of Coiled Coils, Kimberlee Larsen Stern

Theses and Dissertations

Coiled coils are a well-known protein structure prevalent in eukaryotic function, synthetic applications, and de novo protein design. Coiled-coil folding is often described using heptad repeat positions labeled abcdefg where a and d positions occupy the interface between the coils, e and g positions flank the interface, and the b, c, and f positions face the solvent-exposed surface. The a, d, e, and g positions have been extensively studied in the coiled-coil literature. There is a lack of investigation on the impact of the b, c, and f positions on coiled-coil folding. Chapter 1 is an introduction to the heptad …

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