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Biogenetically Inspired Total Synthesis Of Lingzhiol. Design And Synthesis Of Axially Chiral N-Heterocyclic Carbene Catalysts., Krishna Sharmah Gautam

Arts & Sciences Electronic Theses and Dissertations

A stereo- and enantio-selective synthesis of lingzhiol has been achieved, mimicking a proposed biogenetic pathway via Brønsted acid-catalyzed semipinacol rearrangement of a 2,3-epoxy alcohol. A new and improved method was developed for alkylation of anilines using a domestic microwave oven. The resulting racemic chiral anilines were resolved via classical resolution and transformed into axially chiral thiazolylidene-based NHC organocatalysts, which were applied to asymmetric benzoin condensation.

Development Of A Long-Period Torsion Balance For Tests Of Einstein's Equivalence Principle And A Search For Normal Mode Torsional Oscillations Of The Earth, Michael David Abercrombie

Arts & Sciences Electronic Theses and Dissertations

This thesis describes the development of a torsion balance experiment designed to test Einstein's equivalence principle with unprecedented sensitivity, while also taking a novel approach to directly observe the normal mode torsional oscillations of the Earth. Accordingly, a model of the signal expected from a potential equivalence principle violation has been developed, as well as a multi-slit auto-collimating optical lever which possesses a resolution on the order of a nanoradian and a range of observation of 10 milliradians and is used to monitor the torsion balance. A torsion balance with a natural torsional frequency of ~104 Hz, signi_cantly below the …

Survival Analysis In A Clinical Setting, Yunzhao Liu

Arts & Sciences Electronic Theses and Dissertations

With the fast paced advancement of modern medicine, cancer treatments have improved greatly over the past few decades; however, the overall survival rate has not improved for head neck squamous cell carcinoma (HNSCC). Traditionally, the general affected population of HNSCC was male over 50-60 years of age, whom have had history of alcohol and tobacco use. Conversely, in the recent decades, HNSCC has exhibited significant rise in younger patients, largely due to the increase in human papillomavirus (HPV) infection among young adults.

Generally, HPV as the most prevalent sexually transmitted disease, consisted of strains that do not cause harm to …

Actin-Based Feedback Circuits In Cell Migration And Endocytosis, Xinxin Wang

Arts & Sciences Electronic Theses and Dissertations

In this thesis, we study the switch and pulse functions of actin during two important cellular processes, cell migration and endocytosis. Actin is an abundant protein that can polymerize to form a dendritic network. The actin network can exert force to push or bend the cell membrane. During cell migration, the actin network behaves like a switch, assembling mostly at one end or at the other end. The end with the majority of the actin network is the leading edge, following which the cell can persistently move in the same direction. The other end, with the minority of the actin …

Genetic Imputation: Accuracy To Application, Shelina Raynell Ramnarine

Arts & Sciences Electronic Theses and Dissertations

Genotype imputation, the process of inferring genotypes for untyped variants, is used to identify and refine genetic association findings. This body of work focuses on assessing imputation accuracy and uses imputed data to identify genetic contributors to mentholated cigarette preference.

Inaccuracies in imputed data can distort the observed association between variants and a disease. Many statistics are used to assess accuracy; some compare imputed to genotyped data and others are calculated without reference to true genotypes. Prior work has shown that the Imputation Quality Score (IQS), which is based on Cohens kappa statistic and compares imputed genotype probabilities to true …

Market Effect: The Impact Of For-Profit Charter Schools On Racial And Socioeconomic Segregation, William Brett Robertson

Arts & Sciences Electronic Theses and Dissertations

For-profit charter schools are a controversial new development in public education. They combine a structural imperative to maximize profit for private shareholders with the social good of providing public education. This dissertation describes two analyses of for-profit charter schools designed to explore their impact on racial and socioeconomic segregation. The analyses utilize geographic information systems, multilevel modeling, and logistic regression to determine whether and how for-profit charter schools are likely to locate in demographically different neighborhoods, and/or educate demographically different student populations from other types of public schools. The results indicate that for-profit charter schools are less likely than other …

Investigation Of Lung Structure-Function Relationships Using Hyperpolarized Noble Gases, Robert P. Thomen

Arts & Sciences Electronic Theses and Dissertations

Magnetic Resonance Imaging (MRI) is an application of the nuclear magnetic resonance (NMR) phenomenon to non-invasively generate 3D tomographic images. MRI is an emerging modality for the lung, but it suffers from low sensitivity due to inherent low tissue density and short T₂*. Hyperpolarization is a process by which the nuclear contribution to NMR signal is greatly enhanced to more than 100,000 times that of samples in thermal equilibrium. The noble gases ³He and ¹²⁹Xe are most often hyperpolarized by transfer of light angular momentum through the electron of a vaporized alkali metal to the noble …

No-Slip Billiards, Christopher Lee Cox

Arts & Sciences Electronic Theses and Dissertations

We investigate the dynamics of no-slip billiards, a model in which small rotating disks may exchange linear and angular momentum at collisions with the boundary. A general theory of rigid body collisions in is developed, which returns the known dimension two model as a special case but generalizes to higher dimensions. We give new results on periodicity and boundedness of orbits which suggest that a class of billiards (including all polygons) is not ergodic. Computer generated phase portraits demonstrate non-ergodic features, suggesting chaotic no-slip billiards cannot easily be constructed using the common techniques for generating chaos in standard billiards. However, …

Noncommutative Borsuk-Ulam Theorems, Benjamin Passer

Arts & Sciences Electronic Theses and Dissertations

The Borsuk-Ulam theorem in algebraic topology shows that there are significant restrictions on how any topological sphere interacts with the antipodal action of reflection through the origin (which maps x to -x). For example, any map f from a sphere to itself which is continuous and odd (f(-x) = -f(x)) must be homotopically nontrivial. We consider various equivalent forms of the theorem in terms of the function algebras on spheres and examine which forms generalize to certain noncommutative Banach and C*-algebras with finite group actions.

Chapter 1 contains background material on C*-algebras, K-theory, and group actions. Next, in Chapter 2, …

Examining Cost Functionality And Optimization: A Case Study On Testing The Reasonableness Of New Aircraft Using Historical Aircraft Data, Katherine Jozefiak

Arts & Sciences Electronic Theses and Dissertations

When pursuing business by competing for government contracts, proving the submitted price is reasonable is often required. This proof is called a test of reasonableness. This study analyzes data from historical aircraft programs in relation of a new aircraft program in order to demonstrate the estimated cost of the new program is reasonable. The purpose of this study is to investigate three questions. Is the new program cost reasonable using current industry and government parameters? Is it better to look at programs from a total cost perspective or break the total cost into subcategory levels? Finally, this study applies a …

Spot Volatility Estimation Of Ito Semimartingales Using Delta Sequences, Weixuan Gao

Arts & Sciences Electronic Theses and Dissertations

This thesis studies a unifying class of nonparametric spot volatility estimators proposed by Mancini et. al.(2013). This method is based on delta sequences and is conceived to include many of the existing estimators in the field as special cases. The thesis first surveys the asymptotic theory of the proposed estimators under an infill asymptotic scheme and fixed time horizon, when the state variable follows a Brownian semimartingale. Then, some extensions to include jumps and financial microstructure noise in the observed price process are also presented. The main goal of the thesis is to assess the suitability of the proposed methods …

Lead Poisoning In United States Children, Zeren Zhou

Arts & Sciences Electronic Theses and Dissertations

We investigate factors related to blood lead levels of children ages 1 to 5 in the United States for the years 2007-2014. We use data from the National Health and Nutrition Examination Survey (NHANES). The goal is to explore predictors of lead in childrens' blood and to develop a multivariate model using as many predictors as possible. The analysis is conducted using SAS survey regression procedures that account for weighting, stratification, and clustering of the data.

Classification Trees And Rule-Based Modeling Using The C5.0 Algorithm For Self-Image Across Sex And Race In St. Louis, Rohan Shirali

Arts & Sciences Electronic Theses and Dissertations

The study population comprised children, adolescents, and adults who were residents of the city of St. Louis at the time of data collection in 2015. The data collected includes sex, age, race, measured height and weight, self-reported height and weight, zip code, educational background, exercise and diet habits, and descriptions and strategies of participants' weight (i.e. overweight and trying to lose weight, respectively). I use the C5.0 algorithm to create classification trees and rule-based models to analyze this population. Specifically, I model a binary self-image variable as a function of sex, age, race, zip code, and a ratio of reported …

Plate Tectonics Initiation On Earth-Like Planets: Insights From Numerical And Theoretical Analysis Of Convection-Induced Lithospheric Failure, Teresa Wong

Arts & Sciences Electronic Theses and Dissertations

Plate tectonics is central to many aspects of the geology and evolution of terrestrial planets, yet it is only observed on the Earth while all other known planets are covered with a stagnant lithosphere. Plate motions on the Earth are mostly driven by the pull of subducting slabs, therefore understanding the initiation of subduction is crucial to understanding plate tectonics initiation. On a one-plate planet which lacks the forces due to plate motions, some other mechanisms will have to cause the first episode of subduction to mobilize the surface. Sublithospheric convection has been proposed as a possible mechanism that induce …

High-Valent Organometallic Palladium And Nickel Complexes And Their Roles In Carbon-Carbon And Carbon-Heteroatom Bond Formation Reactions, Jason Wesley Schultz

Arts & Sciences Electronic Theses and Dissertations

The development of palladium catalysis has been influential in a wide range of organic transformations, in particular C-C coupling, C-Heteroatom coupling and C-H functionalization reactions. These catalytic transformations normally proceed through the Pd0/II catalytic cycle. These reactions are remarkably useful, however, they suffer from two major problems: -hydride elimination and palladium black deposition. To circumvent these problems, recent reports have been focused on developing novel organic transformations proceeding through high-valent palladium and nickel catalytic cycles.

To this point, we recently reported the isolation and characterization of various mononuclear PdIII complexes using the tetradentate ligands, N,N-di-alkyl-2,11-diaza[3.3](2,6)pyridinophane (RN4, R = tBu, iPr, …

Three Problems In Operator Theory And Complex Analysis, Cheng Chu

Arts & Sciences Electronic Theses and Dissertations

This thesis concerns three distinct problems in operator theory and complex analysis. In Chapter 2, we study the following problem: On the Hardy space H^2, when is the product of a Hankel operator and a Toeplitz operator compact? We give necessary and sucient conditions for when such a product H_fT_g is compact. In Chapter 3, we discuss hyponormal Toeplitz operators. We show that for those operators, there exists a lower bound for the area of the spectrum. This extends the known estimate for the spectral area of Toeplitz operators with an analytic symbol. This part is joint work with Dmitry …

On The Limiting Behavior Of Variations Of Hodge Structures, Genival Francisco Fernandes Da Silva Jr.

Arts & Sciences Electronic Theses and Dissertations

In this dissertation we will address three results concerning the limiting behavior of variations of Hodge structures. The first chapter introduces the main concepts involved and fixes some notation. In chapter two we discuss extension classes representing LMHS, compute them for a class of toric families and introduce an alternative method for the computation of VHS arising from middle convolution. The next chapter is concerned with the so called Apery constants; we provide a method of computing such constants by using higher normal functions coming from geometry. Finally, in the last chapter we analyze a family of surfaces with geometric …

Seismic Array Studies Of Antarctica And Madagascar, Martin James Pratt

Arts & Sciences Electronic Theses and Dissertations

The scope of this dissertation is broad, involving seismic array studies from Antarctica and Madagascar, and includes aspects of glaciology and oceanography as well as solid Earth geophysics. Chapter 2 focuses on the study of stickslip motion of the Whillans Ice Stream, West Antarctica. It includes methods combining seismic array and GPS time series, from ice stream based-sensors, to determine source dynamics in the framework of an earthquake source. The source characteristics are then analyzed to explain far-field seismic observations of ice stream- sourced surface waves detected throughout West Antarctica. Locations of asperities, or sticky- spots, that cause the Whillans …

Seismic Studies Of The Tonga Subduction Zone And The Lau Back-Arc Basin, Songqiao Wei

Arts & Sciences Electronic Theses and Dissertations

This dissertation utilizes multiple techniques of seismic tomography and earthquake location to investigate the upper mantle structure and intermediate-depth seismicity of the Tonga subduction zone, the Lau back-arc basin, and adjacent regions. Data for these studies consist of broadband records from 49 ocean bottom seismographs and 17 island-based seismic stations deployed for one year in 2009-2010, as well as more limited earlier datasets. I conducted tomographic studies of Rayleigh wave velocity and body wave attenuation to examine the thermal variations and the distribution of partial melt in the mantle wedge. The shear-wave velocity structure is first determined using only teleseismic …

Dynamic Pricing And Inventory Management: Theory And Applications, Renyu Zhang

Arts & Sciences Electronic Theses and Dissertations

We develop the models and methods to study the impact of some emerging trends in technology, marketplace, and society upon the pricing and inventory policy of a firm. We focus on the situation where the firm is in a dynamic, uncertain, and (possibly) competitive market environment. The market trends of particular interest to us are: (a) social networks, (b) sustainability concerns, and (c) customer behaviors. The two main running questions this dissertation aims to address are: (a) How these emerging market trends would influence the operations decisions and profitability of a firm; and (b) What pricing and inventory strategies a …

Development And Application Of Comparative Gene Co-Expression Network Methods In Brachypodium Distachyon, Henry David Priest

Arts & Sciences Electronic Theses and Dissertations

Gene discovery and characterization is a long and labor-intensive process. Gene co-expression network analysis is a long-standing powerful approach that can strongly enrich signals within gene expression datasets to predict genes critical for many cellular functions. Leveraging this approach with a large number of transcriptome datasets does not yield a concomitant increase in network granularity. Independently generated datasets that describe gene expression in various tissues, developmental stages, times of day, and environments can carry conflicting co-expression signals. The gene expression responses of the model C3 grass Brachypodium distachyon to abiotic stress is characterized by a co-expression-based analysis, identifying 22 modules …