Digital Commons Network^™

A Four-Dimensional Image Reconstruction Framework For Pet Under Arbitrary Geometries, Aswin John Mathews

McKelvey School of Engineering Graduate Student Theses & Dissertations

Positron Emission Tomography (PET) is a functional imaging modality with applications ranging from the treatment of cancer, studying neurological diseases and disease models. Virtual-Pinhole PET technology improves the image quality in terms of resolution and contrast recovery. The technology calls for having a detector with smaller crystals placed near a region of interest in a conventional whole-body PET scanner. The improvement is from the higher spatial sampling of the imaging area near the detector. A prototype half-ring PET insert built to study head-and-neck cancer imaging was extended to breast cancer imaging. We have built a prototype half-ring PET insert for …

Contextualized Robot Navigation, David Vincent Lu

McKelvey School of Engineering Graduate Student Theses & Dissertations

In order to improve the interaction between humans and robots, robots need to be able to move about in a way that is appropriate to the complex environments around them. One way to investigate how the robots should move is through the lens of theatre, which provides us with ways to analyze the robot's movements and the motivations for moving in particular ways. In particular, this has proven useful for improving robot navigation. By altering the costmaps used for path planning, robots can navigate around their environment in ways that incorporate additional contexts. Experimental results with user studies have shown …

The Synchronized Filtering Dataflow, Peng Li

McKelvey School of Engineering Graduate Student Theses & Dissertations

In the past decade, the world has seen the rise of big data, which calls for a paradigm shift in data processing. Streaming processing, where data are processed in their spatial or temporal order, is increasingly common. Meanwhile, parallel computing has become a household term in the computing world. The combination of streaming processing and parallel computing, streaming computing, has been playing an important role in data processing.

A streaming computing system is a network of nodes connected by unidirectional first-in first-out (FIFO) data channels. When a node has multiple input channels, to ensure the deterministic behavior of the whole …

Novel Mobile Computation Offloading Framework For Android Devices, Meng Wang

McKelvey School of Engineering Graduate Student Theses & Dissertations

The thesis implements an offloading framework for GoogleTM AndroidTM based on mobile devices. Today, the full potential for smartphones may be constrained by certain technical limits such as battery endurance and computational performance. Modern mobile applications own more powerful functions but need larger computation and faster frame rate, which consume more battery energy. Using the proposed offloading framework, mobile devices can offload computational intensive workload to servers to save battery energy consumption and reduce the execution time. The framework can also enable software developers to easily build and deploy services on the servers to support mobile devices to run computationally …

A Liberal State Of Mind: Formal Reconstructions Of Statehood In The Anglophone African Novel, Maya Ganapathy

Arts & Sciences Graduate Student Theses and Dissertations

While the idea of the nation and national identity is often taken as the starting point for examinations of the African state, this dissertation explores the transnational dimensions of the African novel and the way in which English-language writers from Africa imagine a state that more adequately captures their desire to freely inhabit a global literary marketplace. Although critics of the Anglophone African novel tend to understand the fictional state as an object of unremitting political critique (often simply as a reflection of its real-world counterpart), the African state, when viewed through the methodological lens of narrative form, becomes the …

The Late Ordovician Biogeochemical Carbon Cycle, John Garrecht Metzger

Arts & Sciences Graduate Student Theses and Dissertations

The isotopic composition of the carbonate carbon (δ13Ccarb) is one of the best tools for understanding the biogeochemical carbon cycle through Earth history. δ13Ccarb is also used to chemostratigraphically correlate coeval strata. This dissertation has three main foci that all utilize δ13Ccarb as the common data type. The geologic interval investigated was the Late Ordovician (458-444 Ma) with emphasis on the Guttenberg δ13C excursion, a globally correlated, positive ~3 / event that is ~400 kyr in duration. In the first topic we evaluate post-depositional alteration (i.e., diagenesis) of δ13Ccarb signals. In the second topic, we make reconstructions of sea level …

Accelerating Heuristic Search For Ai Planning, You Xu

McKelvey School of Engineering Graduate Student Theses & Dissertations

AI Planning is an important research field. Heuristic search is the most commonly used method in solving planning problems. Despite recent advances in improving the quality of heuristics and devising better search strategies, the high computational cost of heuristic search remains a barrier that severely limits its application to real world problems. In this dissertation, we propose theories, algorithms and systems to accelerate heuristic search for AI planning.

We make four major contributions in this dissertation. First, we propose a state-space reduction method called Stratified Planning to accelerate heuristic search. Stratified Planning can be combined with any heuristic search to …

Gothic Literature And The Politics Of Indistinction, Nicholas Everett Miller

Arts & Sciences Graduate Student Theses and Dissertations

I recover the Gothic as a literature of political possibility. While scholars have long associated the Gothic tradition with political fear, I argue that Gothic novels challenge liberal ideas of the self to produce a sometimes radically egalitarian politics of freedom in the late-eighteenth and early-nineteenth centuries. Edmund Burke made much of the fearfulness of an egalitarian politics in the 1790s, and literary historians have relied on his influence to argue that Gothic fiction is primarily an expression of the fear that comes with the collapse of familial, social, and political distinctions. But fear is not all that accompanies such …

Commentary, Illustration, And Cross-Generic Writing In Paired Editions Of Xixiang Ji And Pipa Ji, Yinghui Wu

Arts & Sciences Graduate Student Theses and Dissertations

This study examines the reproduction and consumption of popular playsXixiang ji(The Story of the Western Wing) andPipa ji(The Lute) as a related pair in seventeenth-century China. During this period, a thriving economy and rapid urbanization stimulated the expansion of commercial publishing. A book market flourished with a bewildering variety of texts and pictures and inventive regroupings of existing materials. Seventeenth-century China has long been recognized as an age of individual creativity, with the elite literati as primary agents, but this study revises the picture by directing attention to the appropriation and transformation of the cultural ideal of "creativity" through the …

Modulation Of Nmda Receptor Activity During Physiological And Pathophysiological Events, Christine Marie Emnett

Arts & Sciences Graduate Student Theses and Dissertations

N-methyl-D-aspartate receptors (NMDARs) are ionotropic glutamate receptors that serve crucial signaling and neurotrophic functions throughout the central nervous system. Both hyperfunction and hypofunction of NMDARs are associated with neurological and neuropsychiatric conditions. Thus, both positive and negative pharmacological NMDAR modulators are of clinical interest as treatments. Understanding drug mechanisms could lead to more rational drug design. Memantine and ketamine are NMDAR open channel blockers that exhibit similar pharmacodynamics at NMDARs but have different clinical uses. Memantine improves cognitive decline during Alzheimer's disease. Ketamine is an anesthetic and analgesic with psychotomimetic effects, but it is also a rapid acting and long-lived …

Reduced Astrocyte Viability At Physiological Temperatures From Magnetically Activated Iron Oxide Nanoparticles, Nicholas J. Schaub, Deniz Rende, Yuan Yuan, Ryan J. Gilbert, Diana Andra Borca-Tasciuc

Chemical and Biochemical Engineering Faculty Research & Creative Works

Superparamagnetic iron oxide nanoparticles (SPIONs) can generate heat when subjected to an alternating magnetic field (AMF). In the European Union, SPIONs actuated by AMF are used in hyperthermia treatment of glioblastoma multiforme, an aggressive form of brain cancer. Current data from clinical trials suggest that this therapy improves patient life expectancy, but their effect on healthy brain cells is virtually unknown. Thus, a viability study involving SPIONs subjected to an AMF was carried out on healthy cortical rat astrocytes, the most abundant cell type in the mammalian brain. The cells were cultured with amino silane- or starch-coated SPIONs with or …

The Impacts Of Climate Change On The World’S Economic, Political, And Demographic Structures, Dino Kanlic

Arts & Sciences Graduate Student Theses and Dissertations

Climate change will have negative impacts on the political, economic, and demographic structures of society. These include a rise in ethnic tensions in the Indian Sub Continent, massive immigration to Europe, regional economic collapse and political destabilization in Africa, the inundation of island nations and economic losses in the Americas among many other changes which will combine to destabilize humanity for generations. International affairs has failed to come up with a solution because global warming is a universal prevention focused problem that trades short term gains for long term losses. Global warming will be solved by the onset of grid …

Bronze Age Potters In Regional Context: Long-Term Development Of Ceramic Technology In The Eastern Eurasian Steppe Zone, Paula Naify Doumani

Arts & Sciences Graduate Student Theses and Dissertations

This dissertation explores the relationship between mobility, social interaction and flows of material technology in Bronze Age Semirech'ye, in southeast Kazakhstan. The work is directed at questions of operational complexity and issues of scale in understanding local and regional material assemblages and craft production in the Bronze Age. The thesis represents the first comprehensive technological analysis of Handmade Steppe Ceramics (HSC) from Semirech'ye. The ceramics date to the Bronze Age (ca. 2400-800BC) and are associated with the work of mobile pastoralists who occupied disaggregated seasonal campsites along the piedmont zone of the Dzhungar Mountains. Pottery data was obtained from newly …

Origin Of Maternal Age Effect In Congenital Heart Disease Risk For Offspring, Claire Elaine Schulkey

Arts & Sciences Graduate Student Theses and Dissertations

Increasing maternal age is widely acknowledged to lead to greater likelihood of pregnancy complications and congenital abnormalities, but the basis of this effect has not been well studied. Often dismissed as the product of oocyte ageing, the mechanistic basis of this maternal age effect is likely more complex.Congenital heart disease is a classic complex disease with multiple genetic and environmental modifiers, including maternal age. Maternal ageing is a known risk-factor in humans, and has been shown to exist in an Nkx2-5 haploinsufficient mouse model for the disease. This mouse model's maternal age risk is dependent upon strain background, with C57BL/6N …

The Influence Of Metacommunity Size On Species Diversity Across Spatial Scales, Lauren Woods

Arts & Sciences Graduate Student Theses and Dissertations

This dissertation explores the influence of metacommunity size and landscape level processes, such as dispersal, on species diversity. A metacommunity is a group of local communities, or patches, connected by dispersal, and metacommunity size can be defined as the number of discrete local patches within a metacommunity. In chapter 1, I developed a framework to predict the effects of habitat destruction, or a reduction in metacommunity size, on the species richness of local patches of different sizes by integrating metacommunity theory with the equilibrium theory of island biogeography. The effect of metacommunity size on species richness in small and large …

Evolution Of Ecological Dominance Of Yeast Species In High-Sugar Environments, Kathryn Marie Williams

Arts & Sciences Graduate Student Theses and Dissertations

Two challenging goals of evolutionary biology are to understand how evolutionary innovations evolve and how they contribute to the success of lineages. Evolutionary innovations may arise following whole genome duplication (WGD) events and they are suspected to contribute to the success of lineages by creating ecological opportunity. However, direct evidence for duplicated genes involved in evolutionary innovations remains rare, and the relationship between evolutionary innovations and the success of lineages may be very complex. In this study, I explore the relationship of evolutionary innovation, WGD, and the ecological dominance of yeast species in high-sugar environments. In budding yeast, a major …

Kinetic Analysis And Inhibition Studies Of Iron-Dependent Histone Demethylases, Barbara Gordon Cascella

Arts & Sciences Graduate Student Theses and Dissertations

The research presented herein focuses on the kinetics and inhibition of the KDM4 subfamily of Jumonji C (JmjC) domain-containing histone demethylases (HDMs). Belonging to the larger class of alpha-ketoglutarate (alpha-KG)-dependent, non-heme iron monooxygenases, the JmjC-HDMs remove methyl groups from mono-, di-, and tri-methylated histone lysine residues through an Fe(IV)-oxo-catalyzed hydroxylation reaction. JmjC-HDMs have been found to play integral roles in the maintenance of genomic integrity as well as in the regulation of transcription. Three KDM4 members were studied: the mixed H3K9/H3K36 demethylases KDM4A and KDM4C, and the pure H3K9 demethylase KDM4E. KDM4C is a hypoxia-inducible factor 1 (HIF-1) target gene …

When Life Happens: Theatres Of Hiv And Complexity In South Africa, Jessica S. Ruthven

Arts & Sciences Graduate Student Theses and Dissertations

This dissertation examines theatre as part of an artistic movement in South Africa to address the social, structural, and emotional repercussions of HIV, as well as a space in which knowledge about HIV/AIDS is actively created, mediated, reproduced, challenged, and presented for public consumption. Although applied theatre has a long history in the country, I focus on innovation in recent theatrical practices that have occurred as artists and members of broader civil society struggle to understand the trajectory of the country's AIDS epidemic and question the scope of popular national HIV intervention campaigns. I use emerging forms of cultural production …

Study Of Ii-Vi Colloidal Semiconductor Magic-Size Nanoclusters And Crystalline Quantum Platelets, Yuanyuan Wang

Arts & Sciences Graduate Student Theses and Dissertations

The main objective of this project is to prepare and isolate the smallest, discrete, magic-size nanoclusters of cadmium selenide (CdSe) and to grow crystalline, wurtzite CdSe quantum platelets (QPs) at room temperature. The achievement of these goals enables us to provide a general synthesis of II-VI semiconductor magic-size nanoclusters and low-temperature routes to well-passivated nanocrystals having a range of compositions and morphologies.The magic-size nanocluster (CdSe)13 is grown in a lamellar-bilayer soft template at room temperature. The results described in this thesis strongly suggest that [(CdSe)13(n-octylamine)13] is the most thermodynamically stable nanocluster and serves as a key intermediate in the formation …

Synthesis And Characterization Of Pbs Quantum Sheets Through Lamellar Assembly, And Updates To The Cdse Quantum Wire Synthesis, Paul James Morrison

Arts & Sciences Graduate Student Theses and Dissertations

This dissertation reports the novel synthesis of PbS quantum plates (QPs) via a reaction executed at low temperatures. The PbS QPs are grown in a template-assisted mechanism, with the first excitonic peak observed in the visible region of light at ~620 nm (2.0 eV), at an energy radically different than the band gap of bulk PbS (~3000 nm, 0.42eV). The large energy shift is due to the extremely thin dimension of these nanoplates, which is determined to be ~1 nm in thickness. Thickness measurements are made in a powder X-ray diffractometer (XRD) at low angles (between 2-15º 2θ). These measurements …

Feeling Doctrine: Religious Meanings Of Emotion In Sixteenth-Century German Literature, Georgia Anna Leeper

Arts & Sciences Graduate Student Theses and Dissertations

This dissertation explores the intersections of emotion and Protestant theology in late-16th-century German literature. The project demonstrates the availability of even secular texts to confessional readings through the analysis of representations of emotions. Post-Reformation texts practice an emotional exemplarity that highlights the effects - including the spiritual effects - which emotional experiences have on the individual. I argue that narrative representations of emotions at this moment reflect anxieties about the nebulous nature of faith, and its central role in Protestant salvation. Close readings of widely-read texts such as the 1587 Faustbuch, Melusine, and Hans Sach's Judith: ein Comedi, among others …

Isotope Harvesting At Heavy-Ion Fragmentation Facilities, Tara Elise Mastren

Arts & Sciences Graduate Student Theses and Dissertations

Isotope harvesting from heavy-ion fragmentation facilities is a potential source of isotopes of interest for applications research. With the upgrade of the National Superconducting Cyclotron Laboratory (NSCL) to the Facility for Rare Isotope Beams (FRIB) usable quantities of many isotopes of interest will be produced and available for harvest from an aqueous beam dump. If available, these isotopes would be of interest to a broad range of applications such as medicine, geology, and stockpile stewardship. Preliminary experiments were performed at the NSCL in order to determine the feasibility of isotope harvesting at (FRIB).A water target station that consisted of a …

Bio-Enhanced Constructivism: Moral Facts For The Naturalistic But Morally Serious Philosopher, Jason Gardner

Arts & Sciences Graduate Student Theses and Dissertations

ABSTRACTBio-Enhanced Constructivism: Moral Facts for the Naturalistic but Morally Serious PhilosopherbyJason GardnerDoctor of Philosophy in PhilosophyWashington University in St. Louis, 2014Professor Eric Brown, ChairThere is a tension between being both morally and naturalistically serious because it is doubtful that features philosophers have ascribed to moral facts in order to explain why we should take them seriously can be given a naturalistic accounting. Yet even serious naturalists who think the tension is real and troubling persist in trying to be serious moralists. I do not think they can do so on their own terms. Thus the purpose of this dissertation: to …

Polyol Synthesis Of Silver Nanowires By Heterogeneous Nucleation And Mechanistic Aspects Influencing Its Length And Diameter, Waynie M. Schuette

Arts & Sciences Graduate Student Theses and Dissertations

Various additives are employed in the polyol synthesis of silver nanowires (Ag NWs), which are typically halide salts such as NaCl. A variety of mechanistic roles have been suggested for these additives. My research showed that the early addition of NaCl in the polyol synthesis of Ag NWs from AgNO3 in ethylene glycol results in the rapid formation of AgCl nanocubes, which induce the heterogeneous nucleation of metallic Ag upon their surfaces. Ag NWs subsequently grow from these nucleation sites. The conclusions are supported by studies using ex-situ generated AgCl nanocubes.Additionally, the final mean silver nanowire diameter is found to …

X-Ray Polarimetry With X-Calibur, Qingzhen Guo

Arts & Sciences Graduate Student Theses and Dissertations

ABSTRACT X-Ray Polarimetry with X-Calibur by Qingzhen Guo Doctor of Philosophy in Physics, Washington University in St. Louis, September, 2014. Professor Henric Krawczynski, Chair X-ray polarimetry is a prime tool to investigate the unexplored compact sources and to provide crucial information that other techniques can not produce. By measuring the degree and orientation of the polarization of radiation from a cosmic source, unique inferences about the morphology and the magnetic field structure can be made. Krawczysnki's group at Washington University is working on a uniquely sensitive scattering polarimeter, X-Calibur, to be used in the focal plane of a focusing X-ray …

Applications Of Nonlinear Optimization, Yao Xie

Arts & Sciences Graduate Student Theses and Dissertations

We apply an interior point algorithm to two nonlinear optimization problems and achieve improved results. We also devise an approximate convex functional alternative for use in one of the problems and estimate its accuracy. The first problem is maximum variance unfolding in machine learning. The traditional method to solve this problem is to convert it to a semi-definite optimization problem by defining a kernel matrix. We obtain better unfolding and higher speeds with the interior point algorithm on the original non-convex problem for data with less than 10,000 points. The second problem is a multi-objective dose optimization for intensity modulated …

Comparison Of Conventional And Bayesian Analysis For The Ultrasonic Characterization Of Cancellous Bone, Amber Groopman

Arts & Sciences Graduate Student Theses and Dissertations

This dissertation investigates the physics underlying the propagation of ultrasonic waves in cancellous bone. Although quantitative ultrasound has the potential to evaluate bone quality even better than the current gold standard X-ray based modality, its clinical utility has been hampered by the incomplete understanding of the mechanisms governing the interaction between ultrasound and bone. Therefore, studies that extend the understanding of the fundamental physics of the relationship between ultrasound and trabecular bone tissue may result in improved clinical capabilities.Ultrasonic measurements were carried out on excised human calcaneal specimens in order to study the effects of overlapping fast and slow compressional …

Characterizing The Fitness Landscapes Of Gut Symbionts In Defined Community And Diet Contexts, Meng Wu

Arts & Sciences Graduate Student Theses and Dissertations

A species' niche is the description of all the environmental conditions required to permit a population of that species to persist, including the effects of the population on those conditions. This definition includes the species' resource requirements, as well as stress tolerances and interactions with other species acting as competitors, predators, parasites, and mutualists. The human gut microbiota serves as a microbial `metabolic organ' tasked in part with the biotransformation of many components of our diet. Relatively little is known about the factors that allow members of the human gut microbiota to persist in a habitat that experiences marked changes …

The Influence Of Confucianism On Identity Formation Of A Multi-Skilled Migrant: An Autoethnography, Annabella Fung

The Qualitative Report

In this autoethnographical study, I examine how my identities were influenced by Confucianism. Two main Confucian concepts were examined: “selfperfection,” and “filial piety and submissiveness.” As a migrant who left Macau for Australia at fifteen, I have been immersed in diverse cultural climates, experienced gender bias, identity crisis and racial discrimination. I consider all experiences as essential steps of my evolution with ethnographic, interpretative, phenomenological and narrative understandings. This paper introduces the term “seasonal fluctuations” as a way to describe the changing meanings of my lived experiences that were interrogated by my three distinctive personalities: The Writer, The Interpreter and …

Hydrodynamics Of Dna Confined In Nanoslits And Nanochannels, K. D. Dorfman, D. Gupta, A. Jain, Douglas R. Tree

Faculty Publications

Modeling the dynamics of a confined, semiflexible polymer is a challenging problem, owing to the complicated interplay between the configurations of the chain, which are strongly affected by the length scale for the confinement relative to the persistence length of the chain, and the polymer-wall hydrodynamic interactions. At the same time, understanding these dynamics are crucial to the advancement of emerging genomic technologies that use confinement to stretch out DNA and “read” a genomic signature. In this mini-review, we begin by considering what is known experimentally and theoretically about the friction of a wormlike chain such as DNA confined in …