Digital Commons Network^™

Progress Toward Applications Of Carbon Nanotube Photoluminescence, Prakrit V. Jena, Thomas V. Galassi, Daniel E. Roxbury, Daniel A. Heller

Chemical, Biomolecular, and Materials Engineering Faculty Publications

In the fifteen years following the discovery of single-walled carbon nanotube (SWCNT) photoluminescence, investigators have made significant progress in their understanding of the phenomenon and toward the development of applications. The intrinsic potential of semiconducting carbon nanotubes – a family of bright, photostable near infrared (NIR) fluorophores (900–2100 nm) with tunable properties, has motivated their use as optical probes and sensors. In this perspective, we highlight the advances made in the synthesis, processing, modification, separation, and metrology of carbon nanotubes in the context of applications of their photoluminescence.

Single Nanotube Spectral Imaging To Determine Molar Concentrations Of Isolated Carbon Nanotube Species, Thomas V. Galassi, Prakrit V. Jena, Daniel E. Roxbury, Daniel A. Heller

Chemical, Biomolecular, and Materials Engineering Faculty Publications

Electronic and biological applications of carbon nanotubes can be highly dependent on the species (chirality) of nanotube, purity, and concentration. Existing bulk methods, such as absorbance spectroscopy, can quantify sp² carbon based on spectral bands, but nanotube length distribution, defects, and carbonaceous impurities can complicate quantification of individual particles. We present a general method to relate the optical density of a photoluminescent nanotube sample to the number of individual nanotubes. By acquiring 3-dimensional images of nanotubes embedded in a gel matrix with a reducing environment, we quantified all emissive nanotubes in a volume. Via spectral imaging, we assessed structural …

Evidence Of Morphological And Functional Variation Among Bluegill Lepomis Macrochirus Populations Across Grand Lake St Mary's Watershed Area, Anthony Bell, Stephen J. Jacquemin

Biological Sciences Faculty Publications

A myriad of factors have been shown to influence the morphology offreshwaterfish. However, studies that parse out where variation is comingfrom (e.g. body size, sex, and habitat) as well as what potential thesechanges have to influence function (e.g. swimming performance) areunderstudied. Therefore, the objectives of this study were to describemorphological variation of BluegillLepomis macrochirusacross the GrandLake St Mary’s watershed area (northwest OH, USA) and test forcovariation of morphology with size, sex, and habitat as well as to assessswimming performance to discern whether any differences in habitat (andmorphology) correspond with functional aspects related to criticalswimming velocity. Geometric morphometric methods were used …

Chevron Step One-And-A-Half, Daniel J. Hemel, Aaron L. Nielson

Faculty Articles

The Supreme Court says that Chevron has two steps: Is the statute ambiguous (Step One), and, if so, is the agency’s interpretation of the ambiguous provision a permissible one (Step Two)? Yet over the last three decades, the DC Circuit has inserted an intermediate step between Steps One and Two: Did the agency recognize that the statutory provision is ambiguous? If not, then the DC Circuit refuses to proceed to Chevron Step Two and remands the matter to the agency. This doctrine— which we dub “Chevron Step One-and-a-Half”—has led to dozens of agency losses in the DC Circuit and DC …

The Emerging American Police State: The Problem Is Not With The Police, But Higher Up, Wiiliam E. Nelson

Faculty Articles

This article argues that concern with reforming the police will not fully deter the emergence of an American police state or significantly reduce the misuse power of by law enforcement agencies. The police are not the problem; the problem is higher up. Undoubtedly, there are rogue police officers who commit heinous acts, up to and including murder. There are rogues in every occupation. Steps are needed to minimize the number of rogues, although they can never be entirely eliminated. It is far more important to pay close attention, not to occasional rogue police officers, but to the institutional structures and …

Effectiveness Of Interactive, Collaborative Vs. Traditional, Lecture-Based Educational Interventions For Adolescents In Low-Income Areas To Increase Knowledge Regarding Sexually Transmitted Infections, Nelan Tagra, Maia Jimenez, Christina Benedicto, Christopher Tucker, Gerrard Norman, Charmein Harris, Stephanie Green

OUR Journal: ODU Undergraduate Research Journal

Aim: To assess whether teens who live in low-income areas who participate in interactive, collaborative sexually transmitted infections (STI) prevention education will have a significant increase in learning outcomes in comparison to students who participate in a traditional, lecture-based approach.

Background: More STIs are reported each year. Among those infected, young people are of the highest incidence at 50% of new STIs in the US annually. High STI incidence is an unintended health outcome as a result of engaging in risky sexual behaviors. This highlights the need to improve STI education among adolescents.

Methods: A quasi-experimental method …

Elder Law & Feminism: Moving Toward Equity In Aging, Emily M. Flesch

Student Scholarship

No abstract provided.

The Effects Of Work-To-Rest Ratios On Torque, Electromyographic, And Mechanomyographic Responses To Fatiguing Workbouts, Ethan C. Hill, Terry J. Housh, Cory M. Smith, Kristen C. Cochrane, Nathaniel D.M. Jenkins, Richard J. Schmidt, Glen O. Johnson

Department of Nutrition and Health Sciences: Faculty Publications

The purpose of the present study was to examine the effects of 2 different work-to-rest ratios, but the same mean load, cycle time, and total duration of the exercise bout, on maximal voluntary isometric contraction torque and neuromuscular responses to fatiguing, intermittent, submaximal, isometric, forearm flexion muscle actions. Ten men performed 2 fatiguing protocols with different work-to-rest ratios (4 s contraction, 4 s rest vs. 4 s contraction, alternating 6 and 2 s rest) that consisted of 50 intermittent, submaximal (65% of maximal voluntary isometric contraction), isometric, forearm flexion muscle actions. Electromyographic and mechanomyographic signals from the biceps brachii were …

Lysin Based Antimicrobial Peptides Against Acinetobacter Baumannii, Mya Thandar

Student Theses and Dissertations

Acinetobacter baumannii is a Gram-negative bacterial pathogen responsible for a range of nosocomial infections. The recent rise and spread of multidrug resistant A. baumannii clones has fueled a search for alternative therapies, including bacteriophage endolysins with potent antibacterial activities. A common feature of these lysins is the presence of a highly positively charged C-terminal domain with a likely role in promoting outer membrane penetration. In the current study, we show that the C-terminal amino acids 108-138 of phage lysin PlyF307, named P307, alone was sufficient to kill A. baumannii (>3-logs). Furthermore, P307 could be engineered for improved activity, the …

Transcriptional Governance Of Hair Follicle Stem Cell Quiescence And Niche Maintenance In Long-Term Tissue Regeneration, Kenneth Lay

Student Theses and Dissertations

Adult stem cells are endowed with the remarkable ability to maintain, regenerate and repair tissues throughout the lifetime of the organism. Whether parsimonious utilization of adult stem cells is necessary to preserve their long-term potential has not been fully explored. I investigated this issue using the adult murine hair follicle stem cell (HFSC) as my paradigm. HFSCs reside in their niche called the bulge, and mostly remain in a quiescent state, becoming mobilized only transiently to fuel cyclical bouts of hair follicle regeneration. By ablating a key HFSC transcription factor, Forkhead Box C1 (FOXC1), I discovered that hair follicles underwent …

Ir Laser-Induced Gene Expression For Tracking Development Of Single Embryonic Neurons And Glia In C. Elegans, Anupriya Singhal

Student Theses and Dissertations

The assembly of neural circuits requires a complex choreography of developmental events: neurons must be generated, extend neurites at the correct time and location, and then integrate extracellular information, like long-range guidance cues or cellular contacts, with an internal developmental program to make correct wiring decisions. Visualizing neural-circuit assembly in vivo can provide insight into how these events are coordinated. The C. elegans embryo, which contains only 222 neurons and 56 glia, is an attractive setting to study nervous system development comprehensively in an intact, living organism. However, methods to label and track optically-resolvable neurites or manipulate single neurons through …

Home Sweet Home: Epigenetic Paths Of Stem Cells In And Out Of Their Niche, Rene C. Adam

Student Theses and Dissertations

Adult stem cells reside in niches, which control their long-term ability to selfrenew and produce the differentiated cell lineages necessary to regenerate and repair their tissues. Following injury, culture or transplantation, stem cells outside their niche often acquire broader plasticity in fates. In my graduate work, I showed that super-enhancers underlie the identity, lineage commitment and plasticity of adult stem cells in vivo. My chosen model is the hair follicle, where its stem cells (HFSCs), niche and master regulators are well-characterized. By mapping global chromatin domains of HFSCs in their native niche, and of committed progenitors, I discovered that super-enhancers …

High Throughput Detection Of Pseudouridine: Caveats, Conundrums, And A Case For Open Science, Maryam Zaringhalam

Student Theses and Dissertations

The isomerization of uridine to pseudouridine (Ψ), known as pseudouridylation, is the most abundant post-transcriptional modification of stable RNAs. Due to technical limitations in pseudouridine detection methods, studies on pseudouridylation have historically focused on ribosomal RNAs, transfer RNAs, and spliceosomal small nuclear RNAs, where Ψs play a critical role in RNA biogenesis and function. For decades, Ψ research was confined to this small subset of cellular RNAs, owing to limitations in methods for Ψ detection. Interest in this modification was reinvigorated, however, with reports that Ψ is conditionally induced in different environmental contexts and that pseudouridylation of certain codons recoded …

Light Sheet Microscopy And Image Analysis Of Neural Development And Programmed Cell Death In C. Elegans Embryos, Peter Insley

Student Theses and Dissertations

The positioning of neuronal cell bodies and neurites is critical for intact functioning of the nervous system. Mapping the positions of the soma and neurites in the brains of developing embryos as important central nervous system structures are being created may yield novel insight into the role of distinct cell groups in creating these structures. New developments in microscopy have made this an excellent time to study neural development in the C. elegans embryo. In the past decade, implementations of highly light efficient methods such as single plane illumination microscopy have rendered it possible to follow development of embryonic structures …

Investigating Differentiation: A Role For Organelle Inheritance In Epidermal Growth, Amma Asare

Student Theses and Dissertations

Balanced growth and differentiation is essential to tissue morphogenesis and homeostasis. How imbalances arise in disease states such as cancers is poorly understood. Loss of differentiation is associated with poorer prognosis in human patients and increasing malignancy in animal models. Here we explore this intersection between growth and differentiation in the context of epidermal development, where populations of stem cells are maintained in careful equilibrium and induced to proliferate and differentiate in response to stimuli such as injury or cyclical growth signals. During development, a naïve epidermis undergoes rapid proliferation and differentiation to form skin containing hair follicles, neurons, immune …

Light Stimulation Of Sensory Hair Cells, Julien Azimzadeh

Student Theses and Dissertations

Hair cells are the mechanosensory detectors that underlie our senses of audition and balance. Their mechanosensitivity arises from direct gating of force-sensitive ion channels by the tension in tip links located at the tops of the stereocilia. The study of hair cells and their mechanically gated channels has heretofore required physical displacement of a hair bundle to open its mechanotransduction channels. The work presented here describes a novel method of hair-bundle stimulation: irradiation with light. The original aim of this study was to elucidate the role of Ca²⁺ in fast adaptation, a process thought to underlie a hair bundle's …

Specification Of Stem Cells And Niche During Hair Follicle Morphogenesis, Tamara Ouspenskaia

Student Theses and Dissertations

Adult stem cell (SC) behavior is tightly coordinated by the signals received from the "niche" - the microenvironment that the SCs reside in. Little is known about the role of the niche in SC specification during organ morphogenesis. In particular, the question of whether the niche exists prior to SC specification or whether it is recruited after SC establishment in a developing tissue remains largely unanswered. In addition, the signals responsible for the specification and regulation of SCs during morphogenesis remain unexplored. To answer these questions, I focused my analysis on the earliest stages of hair follicle (HF) morphogenesis. Using …

The Apoptotic And Wallerian Degeneration Pathways Regulate Disease Onset And Progression In The Sod-1g93a Transgenic Mouse Model Of Als, Deanna Belsky

Student Theses and Dissertations

Amyotrophic Lateral Sclerosis is a neurodegenerative disorder characterized by progressive muscle denervation, motor axon degeneration and the death of motor neurons. The molecular mechanisms that mediate axon degeneration in ALS remain unknown, but motor neuron cell body death occurs through apoptosis. Genetic deletion of the pro-apoptotic gene Bax delays muscle denervation, prolongs disease onset, prevents motor neuron cell death and improves survival in an ALS mouse model. However, the timing and extent of axon degeneration in these mice is unaffected. Here, we examine the role of Sarm1, a component of the Wallerian degeneration pathway, and its interaction with the classical …

A Comparative Study Of Sensory Neuron Synaptic Activity And The Role Of Presynaptic Diversity, Specificity, And Regulation In Caenorhabitis Elegans, Donovan Ventimiglia

Student Theses and Dissertations

Chemical synapses are complex structures that have a diversity of specific activities that shape nervous system computation. To understand how this diversity contributes to specific circuit functions, we sought to characterize synaptic release in the stereotyped and defined neural circuitry of C. elegans. Here we use pHluorin imaging (Vglut-­pH) to monitor presynaptic glutamate release from single chemosensory neurons in intact animals and characterize the dynamics of endo-­ and exocytosis from two types of glutamatergic neurons, AWC^ON and ASH. In Chapter 1, we describe the optimization of Vglut-­pH, we introduce a reagent for measuring synaptic calcium influx by tethering GCaMP …

Compromising The 20s Proteasome Activates A Quality Control Pathway To Mitigate Proteotoxic Stress, Irit Shachrai

Student Theses and Dissertations

The regulation of the ubiquitin-proteasome system (UPS) has been the subject of a vast body of work because of its implication in normal development and a wide range of diseases. The UPS controls the degradation of a large number of cellular proteins and thereby regulates essential cellular processes critical for cellular adaptation and more. Amongst the main processes are removal of mis-folded and potentially toxic proteins, cell's loss of protein quality control is often associated with muscle atrophy and neurodegenerative diseases. The proteasome is subject to tight regulation, as many different proteins govern its transcription, assembly, stability and activity. Consequently, …

Density-Dependent Foraging In Caenorhabditis Elegans, Joshua Greene

Student Theses and Dissertations

Game theory has long predicted that the density of competitors and their behaviors should affect foraging, and moreover suggests that multiple strategies can evolve and co-exist within a single species. I show that both of these predictions are met by foraging Caenorhabditis elegans. In Chapter 2, I show that animals alter their foraging behavior in response to population density, that certain pheromones induce this behavioral change, and that different wild isolates vary in response to the potent ascaroside icas#9. I use QTL mapping to find a major locus responsible for this variation, and map it to an icas#9 receptor, srx-43. …

Single Molecule Ligand Binding Studies On Ccr5 By Fluorescence Cross-Correlation Spectroscopy, Carlos Rico

Student Theses and Dissertations

The G protein-coupled receptor (GPCR) C-C chemokine receptor 5 (CCR5) is the major co-receptor for HIV-1. CCR5 binds to the viral glycoprotein gp120 allowing HIV particles to infect T cells. Currently, maraviroc is the only Food and Drug Administration (FDA) approved entry inhibitor for HIV-1 but resistance to maraviroc has been reported indicating the need for novel entry inhibitors. Recently, four peptides derived from RANTES (Regulated on Activation, Normal T cell Expressed and Secreted), the endogenous ligand of CCR5, were shown to induce different CCR5 signaling pathways and efficiently block viral entry. The peptide analogues are 5P12, which blocks HIV-1 …

Apobec1-Mediated Rna Editing In Monocytes Contributes To Genetic Heterogeneity And Modulates Monocyte Activity And Development, Violeta Rayón Estrada

Student Theses and Dissertations

Post-transcriptional modifications such as alternative splicing have been shown to add to the complexity needed to compensate for the relatively low number of genes found in higher organisms. Many other modifications recently found in mRNA, which cannot be deduced from what is coded in the genome, such a cytidine to uridine and adenosine to inosine editing, reveal that this complexity is ever expanding. Therefore, the current challenge is to understand what is the function of these modifications. In this thesis, I focus on APOBEC1-mediated RNA editing. In higher eukaryotes RNA editing consists of C to U and A to I …

Deconvoluting Cell-Type Specific 3'Utr Isoform Expression In The Adult And Developing Cerebellum, Saša Jereb

Student Theses and Dissertations

Alternative polyadenylation has been implicated in the regulation of mRNA translation and stability, as well as mRNA and protein localization. However, it is unclear to what extent alternative polyadenylation regulates these processes uniquely in specific cell types. Using a newly developed technique, termed conditionally-tagged poly(A) binding protein-mediated mRNA 3' end retrieval by crosslinking immunoprecipitation (cTag-PAPERCLIP), we discovered significant differences in alternative polyadenylation between granule and Purkinje cells in the mouse cerebellum, as well as between proliferating and adult granule cells. Interestingly, among transcripts that differed in alternative polyadenylation in both these comparisons, many were involved in key neuronal functions. We …

Isopeptide And Ester Bond Ubiquitination Regulate Degradation Of The Human Dopamine Receptor 4, Jennifer C. Peeler

Student Theses and Dissertations

The human dopamine receptor 4 (hD4R) is a seven-transmembrane helical G protein-coupled receptor (GPCR) found in neural synaptic membranes. The neurotransmitter dopamine binds to and activates the hD4R, which is involved in central nervous system pathways that modulate cognition and circadian rhythms. The hD4R is the primary dopaminergic receptor for the atypical anti-psychotic drug clozapine, which is used to treat schizophrenia and other cognitive disorders. The hD4R gene is unique among the superfamily of GPCR-encoding genes because within the human population, it contains a variable number of tandem repeat (VNTR) exon polymorphism. Because of the VNTRs, the length of the …

A Neuronal Circuit Architecture For Angular Integration In Drosophila, Jonathan Green

Student Theses and Dissertations

While navigating their environment, many animals keep track of their angular heading over time. However, a neuronal-circuit architecture for computing heading remains unknown in any species. In this thesis, I describe a set of neurons in the Drosophila central complex whose wiring and physiology provide a means to shift an angular heading estimate when the fly turns. I show that these clockwise- and counterclockwise-shifting neurons each exist in two subtypes, with spatiotemporal activity profiles that suggest opposing roles for each subtype at the start and end of a turn. Shifting neurons are required for the heading system to properly track …

Graphical User Interface (Gui) Development For An Optical Communication Simulator, Sratsav Ram Shrestha

All Graduate Theses, Dissertations, and Other Capstone Projects

Modeling and simulation tools have been an integral part of engineering world for a long time. Various Electronic Design Automation (EDA) tools have been extensively used in various industries and research to evaluate the performance of electronic systems. The advancement of such design tools also has influenced the optical communication sector such that there has been a continuous progress on the Photonic Design Automation (PDA) tools. Currently, many software for simulating optical communications are available. However, they are very expensive and conceal the information on how components are modeled. To avoid these constraints, we developed our own PDA software for …

Can Carbon Fluxes Explain Differences In Soil Organic Carbon Storage Under Aspen And Conifer Forest Overstories., Antra Boča, Helga Van Miegroet

Wildland Resources Faculty Publications

Climate- and management-induced changes in tree species distributions are raising questions regarding tree species-specific effects on soil organic carbon (SOC) storage and stability. Quaking aspen (Populus tremuloides Michx.) is the most widespread tree species in North America, but fire exclusion often promotes the succession to conifer dominated forests. Aspen in the Western US have been found to store more SOC in the mineral soil than nearby conifers, but we do not yet fully understand the source of this differential SOC accumulation. We measured total SOC storage (0–50 cm), characterized stable and labile SOC pools, and quantified above- and belowground litter …

Does Seat Location Matter? A Review Of The Proximity Effect In Large And Small Classrooms, Kim Lacroix, Sean Lacroix

Communication Disorders & Special Education Faculty Publications

The proximity effect— whether distance from an instructor correlates with grades— has been the topic of many articles dating back nearly 100 years. Despite this attention, a cleavage in the literature remains. Some authors argue that increased proximity to the instructor negatively relates with academic performance while others maintain no proximity correlation with grades. This paper posits that a consensus does exist: seat location influences grades in larger classrooms but not in smaller ones. To support that position, these authors offer a review of previous literature and add to that body by analyzing student performance in six relatively small community …

Medicine@Yale November/December 2017 Volume 13, Issue 4, Yale School Of Medicine Office Of Communications

Medicine@Yale - development newsletter

Medicine@Yale : advancing biomedical science, education and health care was a print and online newsletter which published news about academics, research and philanthropy for alumni, donors, faculty, students and the general public. It was initially published 6 times a year and then changed to a quarterly schedule. The first issue came out June/Jul. 2005. The final issue was published in May/June 2022, vol. 17, issue 1. Published by Yale School of Medicine, Office of Communications.