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Spontaneous Firing Of Sensory Neurons Modulates The Gain In The Downstream Circuit Of A Simple Olfactory System, Matthew O'Neill

McKelvey School of Engineering Graduate Student Theses & Dissertations

In locusts and other insects, odorants are transduced into electrical signal by the olfactory receptor neurons and transmitted to central circuits for further processing. Previous studies have shown that exogenous variables (e.g., flow rates, humidity, temperature, odor mixtures, etc.) can influence the responses of the sensory neurons and therefore modulate the central circuits. However, how the sensory neuron activity is manipulated to achieve adaptive gain control in the following circuit is yet to be understood. It is possible that the magnitude of the stimulus-evoked response in the receptor neurons, their spontaneous activity, or both of these factors can change how …

Growth Factor Gradient Formation And Release From Peg Microspheres For Nerve Regeneration., Jacob Roam

McKelvey School of Engineering Graduate Student Theses & Dissertations

Many biological processes depend on concentration gradients in signaling molecules. Thus, introduction of spatial patterning of proteins, while retaining activity and releasability, will be critical for the field of regenerative medicine. In particular, the area of nerve regeneration is in need of innovations to improve outcomes. Only about 25% of surgical patients with peripheral nerve damage (~200,000 surgical interventions performed each year) regain full motor function with less than 3% regaining sensation. The use of nerve guidance conduits (NGC’s) which are filled with biomimetic scaffolds is one treatment being explored. These scaffolds, however, lack the spatial patterning of proteins found …

Photoacoustic Microscopy And Photoacoustic Computed Tomography Using High-Frequency Linear Array Ultrasonic Transducers, Guo Li

McKelvey School of Engineering Graduate Student Theses & Dissertations

Photoacoustic tomography (PAT) is a highly promising imaging technology which forms images by detecting the induced pressure waves resulting from pulsed light absorption in biological tissues. Because the excitation source is light, PAT is a very safe, non-ionizing, and non-carcinogenic imaging technology. In biomedicine, PAT has the unique advantage of probing endogenous optical absorbers at different length scales with 100% relative sensitivity. With such scalability, PAT can image anatomical, functional, metabolic, molecular, and genetic contrasts of vasculature, hemodynamics, oxygen metabolism, biomarkers, and gene expression. Among several implementations of PAT, optical-resolution photoacoustic microscopy (OR-PAM) and photoacoustic computed tomography (PACT) are two …

High Resolution Multi-Parametric Diagnostics And Therapy Of Atrial Fibrillation: Chasing Arrhythmia Vulnerabilities In The Spatial Domain, Sarah Gutbrod

McKelvey School of Engineering Graduate Student Theses & Dissertations

After a century of research, atrial fibrillation (AF) remains a challenging disease to study and exceptionally resilient to treatment. Unfortunately, AF is becoming a massive burden on the health care system with an increasing population of susceptible elderly patients and expensive unreliable treatment options. Pharmacological therapies continue to be disappointingly ineffective or are hampered by side effects due to the ubiquitous nature of ion channel targets throughout the body. Ablative therapy for atrial tachyarrhythmias is growing in acceptance. However, ablation procedures can be complex, leading to varying levels of recurrence, and have a number of serious risks. The high recurrence …

Artificial Infinite, Brandon Daniels

Graduate School of Art Theses

This thesis examines the complex history of the sublime, specifically the sublime Void of the Romantics and the newer concept of the technological sublime. From there, I examine the genre of science fiction and it relationship to the sublime, the Void and the grotesque. I use specific examples such Stanley Kubrick’s 2001: A Space Odyssey, Andrei Tarkovsky’s Stalker, and a few others to better understand and apply these concepts. Beginning with these examples, I start to posit what role special effects play in how these films embody these philosophical concepts.

Building on this foundation of research, I go on to …

Gesture As Revelation, Laurel Panella

Graduate School of Art Theses

Abstract

The two divergent paths of fine arts and psychological research come together to demonstrate how physical gesture and facial expression communicates significant meaning regarding human emotion and intention. The conceptual framework of these paintings arises from the artist’s engagement with peer-reviewed psychological studies on Affective Science. The paintings balance qualities of both emotional and intellectual thinking, with the goal of calling them forth in equal strength during the viewing experience. The symbolic and representational language of gesture is examined through the painting titled Precarious Extension. Dynamics of compassion and affect theory are analyzed through the painting Transmission of …

Sustained Dual Drug Delivery Of Anti-Inhibitory Molecules For Spinal Cord Injury Treatment, Thomas Wilems

McKelvey School of Engineering Graduate Student Theses & Dissertations

Regeneration of lost synaptic connections following spinal cord injury (SCI) is limited due to local ischemia, cell death, and an excitotoxic environment, which leads to the development of an inhibitory glial scar surrounding a cystic cavity. Myelin-associated inhibitors (MAIs) and chondroitin sulfate proteoglycans (CSPGs) are major inhibitors to axon growth inhibition found within the glial scar and limit functional recovery. The NEP1-40 peptide competitively binds the Nogo receptor and partially blocks inhibition from MAIs, while chondroitinase ABC (ChABC) enzymatically digests CSPGs, which are upregulated at the site of injury. The first part of this work develops drug delivery systems which …

Bio-Inspired Multi-Spectral Imaging Sensors And Algorithms For Image Guided Surgery, Shengkui Gao

McKelvey School of Engineering Graduate Student Theses & Dissertations

Image guided surgery (IGS) utilizes emerging imaging technologies to provide additional structural and functional information to the physician in clinical settings. This additional visual information can help physicians delineate cancerous tissue during resection as well as avoid damage to near-by healthy tissue. Near-infrared (NIR) fluorescence imaging (700 nm to 900 nm wavelengths) is a promising imaging modality for IGS, namely for the following reasons: First, tissue absorption and scattering in the NIR window is very low, which allows for deeper imaging and localization of tumor tissue in the range of several millimeters to a centimeter depending on the tissue surrounding …

Directed Differentiation And Characterization Of Spinal V3 Interneurons From Mouse Embryonic Stem Cells, Hao Xu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Neuronal populations involved in locomotion controlling central pattern generators within the spinal cord hold great potential for spinal cord injury therapy. Spontaneous recovery in rodent models suggests that a population that can reorganize around an injury site could be useful for functional recovery therapeutics after spinal cord injury. The glutamatergic, commissural, long-extending V3 interneurons shown to balance locomotor rhythm regularity and robustness within central pattern generators in vivo are both an ideal population for spinal cord injury therapeutics and a vital population to study as a part of locomotor circuitry. Unfortunately, due to the scarcity of these cells in the …

Manipulation Of Negative Social Evaluative Fears On Body Dissatisfaction And Eating Behaviors: Does Fear Of Social Evaluation Lead To Disordered Eating?, Cheri A. Levinson

Arts & Sciences Graduate Student Theses and Dissertations

Social anxiety and eating disorders are highly comorbid. Researchers have suggested that there may be shared vulnerabilities that underlie the development of these disorders. Two of these proposed vulnerabilities are fear of negative evaluation and social appearance anxiety (i.e., fear of negative evaluation specifically focused on one’s appearance). Regarding disordered eating, previous self-report research has found that social appearance anxiety may be especially relevant for body dissatisfaction, whereas fear of negative evaluation may be relevant for drive for thinness. In the current study I manipulated fear of negative evaluation and social appearance anxiety using a speech task in 160 undergraduate …

Alternative Histories: Imagining Ancient Britain On The London Stage, 1560-1642, Meredith Anne Beales

Arts & Sciences Graduate Student Theses and Dissertations

I argue that plays set in ancient Britain helped shape early modern concepts of anachronism and history, undermining British identities and the early modern British state. While early modern English historians searched for the noble past which would undergird the creation of a modern empire, the theatre invited audiences to imagine an ancient Britain populated by noble Celts, fierce dragons, prophetic wizards, and defeated Romans, as if all these alternative stories were equally plausible. When scholars study the relationship between British history and identity, they usually bring a twenty-first century understanding of history as distinct from fiction. I show that …

Variation And Plasticity Of Dna Methylation In Genome Regulation, Junchen Gu

Arts & Sciences Graduate Student Theses and Dissertations

DNA methylation is an important and well-studied epigenetic mark. It plays a pivotal role in imprinting, X-chromosome inactivation and genome stability and regulation in many normal development processes. DNA methylation, along with histone modifications, orchestrates the cell type- and developmental stage-specific chromatin landscapes and influences gene expression in vertebrates. In this thesis, I utilized the latest next-generation sequencing based methods to map DNA methylation levels at a genome-wide scale to investigate two areas of interest: the variation of DNA methylation across a large number of sample types and its functional potentials; the plasticity of DNA methylation in response to environmental …

Characterizing And Modeling Antibiotic Resistance Dynamics In Diverse Microbial Communities, Molly Krisann Gibson

Arts & Sciences Graduate Student Theses and Dissertations

Complex microbial communities colonize every habitat investigated to date, including soil, animals, water, and humans, as well as the structures we live in. It has been hypothesized that there is network of exchange allowing both bacterial organisms and functions to seamlessly move between and within these environments. These microbial communities often serve essential and beneficial functions for the host organism or environment. This is particularly evident in the human gut, where microbial communities consistently provide a set of services to its human host, including protecting against enteric pathogens, liberating nutrients from food, and signaling immune system regulation. However, these communities …

Adaptive Mechanisms Of Niche Remodeling In Streptococcus Pyogenes, Elyse Paluscio

Arts & Sciences Graduate Student Theses and Dissertations

The Gram-positive bacterium Streptococcus pyogenes is a remarkably successful pathogen, capable of infecting numerous tissue sites within its human host. The ability of S. pyogenes to invade these different niches is, in part, due to the species’ ability to monitor various physical and chemical signals in its environment and alter its transcriptional profile in response to these differential conditions. As a member of the lactic acid bacteria, S. pyogenes has a simple fermentative metabolism and relies exclusively on a combination of homo-lactic and mixed acid fermentation as a means of generating energy in the cell. As a consequence of its …

Relationship Between Serum Biomarkers And Three-Month Outcomes Following Pediatric Traumatic Brain Injury (Tbi), Alicia Leanne Janos

Arts & Sciences Graduate Student Theses and Dissertations

With more than 475,000 cases annually, traumatic brain injury (TBI) is the leading cause of morbidity and mortality in children. Promising new tools for the prediction of functional outcomes following pediatric TBI are biomarkers of brain injury that can be detected in blood serum. The most commonly studied biomarkers, S100β, neuron-specific enolase (NSE), and myelin basic protein (MBP), have myriad limitations which preclude their use in clinical care. In the present study, serum concentrations of two novel biomarkers of brain injury (i.e., ubiquitin carboxy-terminal hydrolase-L1, UCH-L1; glial fibrillary acidic protein, GFAP) were collected 24 hours following severe TBI in 30 …

The Influence Of Word Frequency And Aging On Lexical Access, Emily Rebecca Cohen-Shikora

Arts & Sciences Graduate Student Theses and Dissertations

Visual word recognition has been a central area of psychological inquiry over the past century. The current dissertation examines how visual word recognition changes as a function of age by focusing on the influence of word frequency, or how commonly a word is encountered. Word frequency is arguably the strongest predictor of visual word recognition performance across a variety of language tasks, and the most influential factor in models of language processing. All models of visual word recognition include a strong role for word frequency but often assume different underlying mechanisms, which produce differing predictions for age changes. Although there …

Physical Activity And Maternal And Neonatal Outcomes In Obese Pregnant Women, Rachel Ann Tinius

Arts & Sciences Graduate Student Theses and Dissertations

Maternal obesity and physical inactivity during pregnancy are independently associated with unfavorable maternal and neonatal metabolic outcomes. Previous research in non-gravid adults suggests physical activity provides protection from many chronic diseases irrespective of body weight. The primary purposes of this dissertation were to determine the impact of obesity on maternal metabolic health (lipid metabolism, inflammation, insulin resistance) and neonatal metabolic health (adiposity, inflammation, insulin resistance), and to determine if adverse maternal and neonatal metabolic health is improved in obese pregnant women who are physically active during pregnancy compared to sedentary obese women. The secondary purpose of this dissertation was to …

Striatal Activity Is Associated With Deficits Of Cognitive Control And Aberrant Salience For Patients With Schizophrenia, Alan E. Ceaser

Arts & Sciences Graduate Student Theses and Dissertations

A recent study has shown that the locus of the largest known dopamine abnormality between patients with schizophrenia and healthy controls is in the associative striatum (Kegeles et al., 2010). This dopamine abnormality in the associative striatum is thought to bring about aberrant salience assignment for patients, which may underlie symptoms of psychosis like delusions and hallucinations (Howes & Kapur, 2009). Interestingly, the associative striatum has segregated, looped, connectivity with cortical regions including the prefrontal and parietal cortices (Draganski et al., 2008; Redgrave, Vautrelle, & Reynolds, 2011) and computational models have suggested that it may function as an information gate …

“We Average Unbeautiful Watchers”: Reflexive Fans And The Readerly Stakes Of American Sports Narratives, Noah Cohan

Arts & Sciences Graduate Student Theses and Dissertations

“We Average Unbeautiful Watchers” traces the role of the American sports fan across literary genres from the novel to the memoir to the blog post. Representing mass-mediated athletics as fundamentally narrative-based entertainments, I argue that fans function as readers whether they realize it or not. Further, while it may seem that sports narratives are “written” by athletes and assigned meaning by journalists, my project demonstrates that fans appropriate those narratives in diverse ways to form their own sense of identity. Inscribed in Don DeLillo’s Underworld (1997), Fred Exley’s A Fan’s Notes (1968), David Shields’s Black Planet (1999), and the blog …

Bound To Aim At Good Generally: A Sidgwickian Argument For Rational Impartialism, Tyler Stephen Paytas

Arts & Sciences Graduate Student Theses and Dissertations

In this dissertation I defend an unorthodox theory of practical reason called Rational Impartialism. According to this view, one ought to have equal fundamental concern for the equal good of everyone. Central to my argument for Rational Impartialism are two of Henry Sidgwick’s axioms of ethics. According to the axiom of Equal Good, one ought to have equal fundamental concern for equal portions of the good. According to the axiom of Personal Irrelevance, the equal good of any two individuals is exactly similar qua portions of universal good. Sidgwick claims that from these two axioms we can deduce a principle …

Redeeming The Information Overload: A Case Study On Doon University , Dehradun, Manoj Kumar Pant Mr., Udita Negi Mrs

Library Philosophy and Practice (e-journal)

Higher education in India is in a process of transition, from traditional, colonial and static system to a more competitive system based on global market philosophy. The present survey provides an insight to the status of information awareness and literacy among the students of Doon University. Thus, there is a pressing need for empirical analyses to identify the extent to which university students are information-literate.

Functional Identification And Characterization Of Cis-Regulatory Elements, Christopher Michael Fiore

Arts & Sciences Graduate Student Theses and Dissertations

Transcription is regulated through interactions between regulatory proteins, such as transcription factors (TFs), and DNA sequence. It is known that TFs act combinatorially in some cases to regulate transcription, but in which situations and to what degree is unclear.I first studied the contribution of TF binding sites to expression in mouse embryonic stem (ES) cells by using synthetic cis-regulatory elements (CREs). The synthetic CREs were comprised of combinations of binding sites for the pluripotency TFs Oct4, Sox2, Klf4, and Esrrb. A statistical thermodynamic model explained 72% of the variation in expression driven by these CREs. The high predictive power of …

A Gnotobiotic Mouse Model For Studying The Effect Of Human Gut Community Ecology On A Pathobiont, Bacteroides Fragilis, Vitas Wagner

Arts & Sciences Graduate Student Theses and Dissertations

ABSTRACT OF THE DISSERTATIONA Gnotobiotic Mouse Model for Studying the Effect of Human Gut Community Ecology on a Pathobiont, Bacteroides fragilisbyVitas WagnerDoctor of Philosophy in Biology and Biomedical SciencesEvolution, Ecology, and Population BiologyWashington University in St. Louis, 2015Professor Jeffrey I. Gordon, ChairChildhood undernutrition represents a pressing global health challenge. Epidemiologic studies have shown that undernutrition is not due to food insecurity alone, but rather represents a complex set of interactions between intra- and intergenerational factors. The gut microbiota has been implicated as one such factor. This thesis tested the hypothesis that enteropathogen burden affects the structure and expressed functions of …

Essential Roles Of Stat3 In Zebrafish Development, Yinzi Liu

Arts & Sciences Graduate Student Theses and Dissertations

Vertebrate gastrulation is a fundamental morphogenetic process during which germ layers are formed, patterned and shaped into a body plan with organ rudiments. Among the conserved gastrulation movements, convergence and extension (C&E) occur concurrently to narrow the germ layers mediolaterally and elongate them along the anteroposterior embryonic axis. C&E are largely driven by cell migration and cell intercalation, while cell proliferation has been considered dispensable and even incompatible with gastrulation movements and morphogenesis. Signal transducer and activator of transcription 3 (Stat3) has been implicated by antisense morpholino loss-of-function study in regulation of zebrafish C&E movements in part by promoting non …

Host Immune Signals Regulate Blood-Brain Barrier Function During Central Nervous System Infection And Autoimmunity, Brian Daniels

Arts & Sciences Graduate Student Theses and Dissertations

A major hallmark of neuroinflammatory diseases is the breakdown of the blood-brain barrier (BBB). This barrier between the hematogenous circulation and the parenchyma of the central nervous system (CNS) is a multicellular interface made up of endothelial cells joined by tight and adherens junctions (TJs and AJs), along with pericytes and the endfeet projections of astroglia. Together, these cells tightly restrict the movement of solutes and cells from the circulation into the CNS in a manner crucial for proper CNS homeostasis. Regulation of BBB function occurs dynamically during neuroinflammatory diseases such as infection and CNS autoimmunity, resulting in both protective …

Functional Characterization Of Putative Rab Geranylgeranyltransferase Subunits In Arabidopsis Thaliana, Wan Shi

Arts & Sciences Graduate Student Theses and Dissertations

Protein prenylation is one of the posttranslational lipid modifications that facilitate protein-membrane association and protein-protein interactions. Three types of heterodimeric protein prenyltransferases, protein farnesyltransferase (PFT), protein geranylgeranyltransferase-I (PGGT-I), and protein geranylgeranyltransferase-II or Rab geranylgeranyltransferase (Rab-GGT), are present in all eukaryotes. In Arabidopsis there are two putative genes encoding Rab-GGT α subunits, termed RGTA1 and RGTA2, and two putative genes encoding β subunits, RGTB1 and RGTB2, but little is known about Arabidopsis Rab-GGT activity. In this dissertation, I demonstrate that four different heterodimers can be formed between RGTA1, RGTA2, RGTB1, and RGTB2, but only RGTA1-RGTB1 and RGTA1-RGTB2 exhibit bona fide Rab-GGT …

Neural Basis Of Functional Connectivity Mri, Jingfeng Li

Arts & Sciences Graduate Student Theses and Dissertations

The brain is hierarchically organized across a range of scales. While studies based on electrophysiology and anatomy have been fruitful on the micron to millimeter scale, findings based on functional connectivity MRI (fcMRI) suggest that a higher level of brain organization has been largely overlooked. These findings show that the brain is organized into networks, and each network extends across multiple brain areas. This large-scale, across-area brain organization is functionally relevant and stable across subjects, primate species, and levels of consciousness.This dissertation addresses the neural origin of MRI functional connectivity. fcMRI relies on temporal correlation in at-rest blood oxygen level …

Escherichia Coli Iron Acquisition Paradigms And Host Responses In The Human Urinary Milieu, Robin Reid Shields-Cutler

Arts & Sciences Graduate Student Theses and Dissertations

Urinary tract infections (UTIs) are some of the most common bacterial infections worldwide and are increasingly complicated by high antibiotic resistance and recurrence rates. Explanations for the marked individual differences in UTI susceptibility remain incomplete. In this thesis we show that urinary colonization by uropathogenic E. coli (UPEC) is influenced by urine composition and the activity of an important innate immune protein, siderocalin (SCN; also called lipocalin 2 or neutrophil gelatinase-associated lipocalin/NGAL). During UTI, host factors limit the availability of iron, an essential nutrient for the invading pathogen. In response, UPEC modify the urinary environment with metal binding siderophores, some …

Neural Mechanisms Of Working Memory Cortical Networks, Charalampos Papadimitriou

Arts & Sciences Graduate Student Theses and Dissertations

This dissertation is aimed at understanding the cortical networks that maintain working memory information. By leveraging patterns of information degradation in spatial working memory encoding we reveal new neural mechanisms that support working memory function and challenge existing models of working memory circuits.First we examine how interference from previous memoranda influences memory of a currently remembered location. We find that memory for a currently remembered location is biased toward the previously memorized location. This interference is graded, not all-or-none. Interference is strongest when the previous and current targets are close and activate overlapping populations of neurons. Contrary to the attractive …

Dissection Of Affective Catecholamine Circuits Using Traditional And Wireless Optogenetics, Jordan Gary Mccall

Arts & Sciences Graduate Student Theses and Dissertations

Parsing the complexity of the mammalian brain has challenged neuroscientists for thousands of years. In the early 21st century, advances in materials science and neuroscience have enabled unprecedented control of neural circuitry. In particular, cell-type selective manipulations, such as those with optogenetics and chemogenetics, routinely provide answers to previously intractable neurobiological questions in the intact, behaving animal.In this two-part dissertation, I first introduce new minimally invasive, wireless technology to perturb neural activity in the ventral tegmental area dopaminergic system of freely moving animals. I report a series of novel devices for studying and perturbing intact neural systems through optogenetics, microfluidic …