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Mechanisms Of Interaction Between Haemophilus Parainfluenzae And Streptococcus Mitis, Dasith Perera

Open Access Dissertations

The human oral cavity is a complex polymicrobial environment, home to an array of microbes that play roles in health and disease. Oral bacteria have been shown to cause an array of systemic diseases and are particularly concerning to type II diabetics (T2D) with numerous predispositions that exacerbate bacterial infection. In this dissertation, we investigated the serum of healthy subjects and T2D subjects to determine whether we see greater translocation of oral bacteria into the bloodstream of T2D individuals. We didn’t observe any significant enrichment of oral taxa, however we detected the presence of an emerging pathogen, Acinetobacter baumannii that …

Biodiversity And Biogeography Of Protist Communities In Coastal Marine Ecosystems Across Indonesia, Erin Borbee

Open Access Dissertations

Despite a long history of biodiversity and biogeography research in Indonesia we know very little about protist communities across this region. What we do know about protist communities across Indonesia is largely based on visual surveys, which have been proven to vastly underestimate protist diversity. The combination of immense biodiversity, oceanographic significance, and human activity across this region make it an interesting setting for understanding the relative effects of abiotic and biotic drivers of protist community structure. The work presented in this dissertation uses metabarcoding to characterize protist community composition and underwater visual census (UVC) data to characterize fish and …

Molecular Ecology Of Marine Diatoms, Bacteria, And Their Biologically-Active Compounds, Alexa R. Sterling

Open Access Dissertations

This dissertation focuses on the molecular ecology of diatoms in the marine environment as it relates to co-occurring associated bacteria, spatial and temporal gradients of physical and chemical oceanographic parameters, and even biotoxin production. The study sites range from the polar habitat of the Southern Ocean (SO) surrounding the Western Antarctic Peninsula (WAP) to the productive estuary Narragansett Bay (NBay) in Rhode Island, USA. The WAP exhibits a naturally occurring gradient of a dissolved iron (Fe), which is an essential micronutrient that diatoms need for growth. Dissolved Fe is growth-limiting in the offshore area and replete in the nearshore areas. …

Large Eddy Simulation Of Turbulent Airflow Over Surface Waves And Air-Sea Fluxes, Nyla Tauqir Husain

Open Access Dissertations

There is a growing need to improve the prediction and parameterization of momentum, energy, heat, and gas exchanges between the ocean and atmosphere. It is well known that the coupling between turbulent wind and a spectrum of waves significantly modifies turbulent air-sea fluxes, thereby playing an important role in the development of wave, weather, and climate patterns. Due to the limitations of field measurements, especially in high-to-extreme wind conditions such as tropical cyclones, constraining air-sea fluxes in numerical wave, storm surge, weather, and climate forecast models continues to be a challenge due to our incomplete understanding of near-surface turbulence in …

Single-Walled Carbon Nanotubes For Advanced Optical Materials, Wearable Biosensing, And Bioimaging, Mohammad Moein Safaee

Open Access Dissertations

Single-walled carbon nanotubes (SWCNTs) functionalized with synthetic or natural polymers are a class of advanced optical nanomaterials that have recently found applications in a wide range of molecular diagnostics platforms as biosensors and bioimaging agents. Despite their widespread applications, there is an urgent need to develop standard characterization assays to evaluate their optical, physical, and interfacial properties in vitro and in complex biological environments. The results from such assays are essential for defining general design principles for nanotube-based optical probes and biosensing devices. Moreover, to fully exploit the nanotube's unique properties for health monitoring, it is essential to employ micro- …

Optical Properties Of One Dimensional Quaternary Photonic Crystals And Associated Heterostructures, Nicholas J. Bianchi

Open Access Dissertations

The research conducted in this dissertation is the theoretical investigation into the transmission properties of one dimensional inversion symmetric quaternary photonic crystals and heterostructures created by combining quaternary and binary crystals. A photonic crystal is a device constructed from dielectric or conducting scattering elements arranged in a periodic manner. Saying a crystal has inversion symmetry simply means that the individual unit cells do too. Inversion symmetry is needed to ensure the system remains reciprocal and that topological phase of bands in a band structure remains discrete. The terms "binary" and "quaternary" refer to the number of layers in a unit …

A Mixed Methods Study Of Communication Among Ten Men Members And Community Men, Valerie Ryan

Open Access Dissertations

Ten Men is a primary prevention strategy, which involves a group of prominent men in the community who want to change the social norms around masculinity in Rhode Island and educate other men on the link between toxic masculinity and intimate partner violence (IPV). One way to accomplish this goal of social norms change is by having the Ten Men members, both current and alumni, communicate with men in their local communities about these topics. I evaluated the effectiveness of men’s communication utilizing a mixed methods approach, which incorporated both causal methods applied to network analysis (quantitative) and focus groups …

Two Variants Of Cops And Robbers With Asymmetric Movement Rules, Eric Peterson

Open Access Dissertations

This dissertation presents two variants of Cops and Robbers that feature asymmetric movement, meaning that the cops and robber have different rules for traversing the edges of the graph. The first variant discussed is the bridge-burning variant, wherein the game is played on an undirected graph and the robber deletes any edge he traverses. The second variant discussed is the weak directed variant, wherein the game is played on a directed graph; here the cops can only move along each edge in the direction it points, whereas the robber can traverse each edge in either direction. In both variants, we …

Development Of Novel (Thio)Urea Organocatalysts For Ring Opening Polymerization Of Cyclic Lactones, Nayanthara Dharmaratne

Open Access Dissertations

Amidst multiple catalysts for ROP, H-bonding organocatalysts stand out in the precise level of reaction control they are able to render during ROP. The H-bonding class of organocatalysts are thought to effect ROP via dual activation of both monomer and chain end. The only drawback of these class of catalysts is the low activity shown despite their high selectivity towards ROP.

A new class of H-bond donating ureas was developed for the ring-opening polymerization (ROP) of lactone monomers to address this problem of low activity. The most active of these new catalysts, a tris-urea H-bond donor, is among the most …

The Kingian Nonviolence Conflict Reconciliation Training Program: Outcomes For High School Students’ Cultural, Social, And Emotional Learning, Khadijah Nelly Cyril

Open Access Dissertations

Violence refers to any act or behavior that causes harm (Centers for Disease Control and Prevention [CDC], 2018), and is considered a serious public health issue. Violence puts a burden on individuals, families, and communities, which in turn cause physical and psychological damage. Kingian Nonviolence Conflict Reconciliation Program (Kingian Nonviolence) is an introductory program that serves to address the root causal conditions of violence within oneself and the greater community. Kingian Nonviolence operates on the principle that nonviolence is the only antidote for violence. Core concepts discussed in Kingian Nonviolence include: violence, nonviolence versus non(-hyphen)violence, compassion, values, conflict, conflict resolution, …

Multi-Scale Assessment Of Hurricane-Generated Coastal And Inland Flooding Using A Numerical And Observational Framework, Soroush Kouhi

Open Access Dissertations

Tropical cyclones - also called hurricanes and typhoons - result in major damage and fatalities around the world almost every year due to the massive coastal and inland flooding. Integrating coastal and inland regional flooding models as well as assessing the impacts of climate change helps better understand the overall risk of a hurricane at the present and in the future. Coastal flooding causes damages to the coastal structures. While regional models are not capable of accurately predicting the damage to the coastal structures, the high-fidelity computational fluid dynamics (CFD) models can be implemented to simulate the flow properties around …

Subseafloor Porewater Paleosalinity And Nitrogen Isotopes, Kira Louise Homola

Open Access Dissertations

Sedimentary porewater chemical and isotopic profiles contain complex records of past bottom water composition which are overprinted by in situ biotic and abiotic reactions. We developed a density-based method to determined relic deep water salinities and applied it to map global scale water mass properties and distributions in the deep northwest Atlantic at four previously unsampled sites. Paleosalinities determined by density have higher precision and accuracy than previously published results and confirm the northward expansion of southern deep water and a reversal in the Atlantic’s bottom water meridional salinity gradient during the Last Glacial Maximum (Chapter 1 & 2).

Nitrogen …

Gold And Copper-Cysteamine Nanoparticles For Radiation Therapy Enhancement On Cancer, Bindeshwar Sah

Open Access Dissertations

Radiation therapy is a common technique to kill cancer cells. The purpose of this experiment is the enhancement of radiation effect on the treatment of tumors. The main difficulty of radiation therapy is that it can damage cancerous cells as well as healthy cells. Gold nanoparticles can enhance effects of the radiation treatment on tumors due to the interaction of radiation with gold nanoparticles to produce extra electrons through the Auger effect. This causes reduced side effects on healthy cells though using less radiation dose and maximizes radiation damage on cancer cells through the extra electrons produced by the gold …

Opening Ceremony: A Writing Practice Towards Queer Futurity, Laura Marie Marciano

Open Access Dissertations

Opening Ceremony is a collection of poems in completion of a creative dissertation in poetry at the University of Rhode Island. The book is a five-year writing practice towards queer futurity and considers, both in form and content, how poems can transgress hierarchal binaries and create exit discourse. The poems use lyric imagery, reference to color and material, space on the page, and colloquial language, to write the bodies, aesthetics, and experiences of contemporary queer life. It is a practice of not rallying against hetero-patriarchy, capitalism and white supremacy, which may restabalize binaries, but rather, giving homage to that which …

Ecologies Of Materiality And Aesthetics In British Modernist War-Time Literature, 1890-1939, Molly Volanth Hall

Open Access Dissertations

This dissertation examines landscape representation in English novels, memoirs, manifestos, and poetry between 1890 and 1939 responding to World War I and the larger dynamics of imperialism of which it is a part. Analyzing how such works reflect and reshape dominant environmental perception during the early twentieth century’s marked acceleration of mass warfare and ecological change, it reads for the way images of mud, stone, land, and soil—collected under the term base matters—express the entanglement of environmental and national structures of feeling ranging from fear to dissociation. These base matters dominate characters’ and authors’ changing perception of the material world …

Impacts Of Shoaling Ocean Surface Waves On Wind Stress And Storm Surge, Xuanyu Chen

Open Access Dissertations

Ocean surface waves have been known to affect the wind stress, or air-sea momentum flux, in the open ocean under tropical cyclones. As a tropical cyclone (TC) makes landfall, the surface waves shoal as they enter the shallower coastal waters (< 30~50 m). The impacts of these shoaling surface waves on the wind stress have not yet been thoroughly investigated, but they have been postulated to be important for storm surge prediction. In this study, the WAVEWATCH III (WW3) model is used to simulate the depth modifications on the surface wave fields and the wind stress. Two wave-spectrum based wind stress estimation modules in the WW3 model are used to quantify the impact of wave shoaling on wind stress and drag coefficient under steady uniform wind and tropical cyclone conditions. The consequence of using the shoaling wave modified wind stress for modeling storm surge is investigated using the Advanced Circulation (ADCIRC) model.

For the shoaling wave simulations, an accurate wave field generated by tropical cyclones in the open ocean needs to be established first. The sensitivity of tropical cyclone wave simulations in the open ocean to different spatial resolutions (1/3 °, 1/6 °, 1/12 ° and 1/24 °) is evaluated using two wave models, WW3 and Simulating WAves Nearshore. Results from …

The Role Of Kindergarten Vocabulary Knowledge And Language Status On Early Reading Comprehension, Jennifer Cruz

Open Access Dissertations

The purpose of this study was to investigate the impact of receptive vocabulary knowledge on first and second grade reading comprehension for 340 Kindergarten Dual Language Learners (DLLs) and monolingual students. An additional purpose of the study was to examine the effect of a Tier 2 vocabulary intervention on students’ reading comprehension abilities. Linear regression analyses found statistically significant interactions between initial vocabulary knowledge and DLL status, as well as initial vocabulary knowledge and intervention treatment condition on first grade reading comprehension. Vocabulary at the end of Kindergarten and the change in vocabulary scores also significantly predicted first grade comprehension. …

Development Of Organocatalysts For Ring-Opening Polymerization (Rop) Of Lactones, Rukshika Shalani Hewawasam

Open Access Dissertations

Organocatalysis for Ring-Opening Polymerization (ROP) has come a long way in recent developments to afford precisely tailored and highly adorned biodegradable polyesters. A remarkable milestone of the organocatalysts occurred in 2005 with the advent of dual H-bonding catalysts that produce superior reaction control and molecular weight distributions (Mw/Mn), which is ideal for material applications. However, these organocatalysts do not show the capability in faster reaction times which is limiting the feasibility for industrial implementation.

The polymerization of cyclic esters by (thio)urea/base cocatalyst has proved to be effective and controlled. One method of devising improved catalyst …

The Influence Of Polymethyl Methacrylate Interfaces On The Fluorescence Of Rhodamine 6g Thin Films, Navid Chapman

Open Access Dissertations

A three-layer fluorescence sensing platform is described. The sensor consists of an ultra-thin fluorophore layer of Rhodamine 6G (Rh6G) on top of a sub-micron polymer film of polymethyl methacrylate (PMMA) on top of a rigid glass support. Both fluorophore and polymer layers are prepared by spin-coating, a common industrial process for repeatable deposition of thin films of uniform thickness. First, we study the preparation of PMMA films. Using an accepted equation of state, we closely examine spin-coating dynamics and show that casting solution concentration and spin speed process parameters can be used to modulate the final thickness and surface morphology …

Determining Impacts Of Iron Limitation On Diatom Chloroplast Metabolism And Physiology, Kristofer Gomes

Open Access Dissertations

Within the marine ecosystem, phytoplankton such as diatoms experience regions of nutrient limitation including macronutrients such as nitrogen, silica, and phosphate. In regions with high concentration of these nutrients but low chlorophyll a concentrations (HNLCs), phytoplankton are limited for micronutrients such as iron (Fe) an element that serves as a co-factor in proteins involved in cellular redox reactions. Of particular interest for diatoms is the Fe requirement of cellular processes localized to the chloroplast. These Fe requirements are in multiple metabolic pathways such as light reactions of photosynthesis that generate the necessary energy and reducing power necessary for anabolic processes …

Modulation Of Receptor Interacting Protein Kinase 1 (Ripk1) Signaling During Dengue Virus Infection, Darshika Jeewanthi Udawatte

Open Access Dissertations

Dengue virus (DENV) infection is the most prevalent arthropod-borne virus disease. There are estimated 100 million symptomatic cases of dengue disease per year worldwide. A lack of effective antiviral therapies or vaccines makes DENV infections a major global health concern. Therefore, understanding the viral and host factors contributing to the disease pathogenesis is critical. DENV has been shown to effectively counteract host innate immune mechanisms. In particular, DENV protease, NS3 has emerged as an inhibitor of host cellular signaling by targeting crucial host proteins. Here we identified RIPK1 as a novel target of DENV NS3. RIPK1 is a central mediator …

Design And Validation Of Smart Fabric Sensors Based On Semiconductive Polymer Composites, Arar Alkhader

Open Access Dissertations

Smart Fabric Sensors (SFSs) have recently gained much interest as they are convenient as a long-term wearable as well as for their simplicity, lightweight, low manufacturing cost, high sensitivity, and flexibility. Semiconductive polymer composites SCPCs can be used as smart fabrics to create force or pressure sensors based on the piezoresistive effect, however, their wider application is limited due to their narrow sensing range, hysteresis and output drift issues as well as due to the lack of literature studying their voltage response related errors especially under high impact forces. In this Doctoral research, eight proposed designs of a smart fabric …

The Biogeography Of Antarctic Marine Diatoms And Their Response To Varied Iron Concentrations, Laura Z. Holland

Open Access Dissertations

Diatoms are a group of highly diverse photosynthetic eukaryotes that account for about 40% of oceanic primary production. In large areas of the ocean deemed high nitrate, low chlorophyll (HNLC) regions, dissolved macronutrient (nitrogen, phosphorus, silica) concentrations are high in the surface but diatom biomass is consistently low. The Southern Ocean (SO) is the largest of these environments, and when exogenous Fe is supplied to this region, large diatoms blooms and subsequent carbon export are promoted. As such, SO diatoms are major players in the global carbon cycle and were the focus of this dissertation. This work sought to determine …

Assessing Treatment Performance Of Advanced Nitrogen-Removal Onsite Wastewater Treatment Systems, Bianca Noelle Ross

Open Access Dissertations

Wastewater is a major source of nitrogen (N) to groundwater and coastal waterbodies, threatening both environmental and public health. Advanced N-removal onsite wastewater treatment systems (OWTS) are used to reduce effluent N concentration through biological N removal (BNR). Despite the important role that these systems play in treating nutrient- and pathogen-rich wastewater, few studies have targeted the mechanisms involved in N removal, their capacity to produce effluent to meet regulatory standards, or their impact on the atmosphere.

I evaluated effluent total N (TN) concentration, the structure and composition of N-removing microbial communities, and greenhouse gas fluxes of advanced N-removal OWTS …

The Impact Of A Curricular Change On Undergraduate Human Anatomy And Physiology Students’ Academic Behavior And Performance, Jessica A. Adams

Open Access Dissertations

This dissertation explores learning in context. Undergraduate introductory human anatomy and human physiology courses are either taught as discipline-specific or integrated anatomy and physiology (A&P) sequences. These courses are critically important to future health care professionals yet a consensus is lacking on the optimal course approach. Our institution underwent a curricular revision to change pedagogical methodologies from discipline-specific human anatomy and human physiology to an integrated A&P I and II sequence. Thus, providing a unique opportunity to study the potential impact of contextual learning. Specifically, over three years the effects integrating physiological concepts had on anatomy education were explored as …

Multiscale And Multiphysics Modelling Of Durable Infrastructure Materials, Sumeru Nayak

Open Access Dissertations

Infrastructure is the backbone of America’s 18.57 trillion-dollar economy. The current condition of America’s deteriorating infrastructure network, however, is the cause of serious safety, quality of life, and economic concerns. According to the recent American Society of Civil Engineers’ (ASCE) 2017 Report Card, America’s Infrastructure received a score of D+. According to ASCE’S annual report, the US economy is expected to lose $4 trillion in GDP by 2025 and $14 trillion in GDP by 2040 if current concerns are not addressed and infrastructure continues to deteriorate at current rates. Clearly, there is a need for bold and forward thinking solutions …

Investigation Of Landslide-Induced Tsunami Generation And Propagation Through Numerical Modeling, Lauren Schambach

Open Access Dissertations

This body of work consists of three manuscripts regarding numerical modeling of landslide-induced tsunamis.

Landslide Tsunami Hazard Along the Upper US East Coast: Effects of Slide Deformation, Bottom Friction, and Frequency Dispersion

Numerical simulations of Submarine Mass Failures (SMFs) are performed along the upper US East Coast to assess the effect of slide deformation on predicted tsunami hazard. Tsunami generation is simulated using the three-dimensional nonhydrostatic model NHWAVE. For rigid slumps, the geometry and law of motion are specified as bottom boundary conditions. Deforming slide motion is modeled using a depth-integrated bottom layer of dense Newtonian fluid, fully coupled to …

Microplastic In Water And Wastewater, Dounia Elkhatib

Open Access Dissertations

This thesis addresses three challenges related to the microplastic contamination in water and wastewater treatment plants. The first challenge is the multiple methodologies used to collect, quantify, and characterize microplastics in both wastewater and drinking water. Our study shows a lack of consensus regarding the techniques used at all of the stages (from collection to characterization) required for the quantification of microplastics in urban water systems. This represents a barrier to accurately determine the loads of microplastic contamination and to the comparison of the results obtained among different studies. Our results indicate large discrepancies in the concentrations reported in both …

Making Sense Of Public Scientific Controversy: A Case Study Examining Science Communication And Public Engagement Surrounding Genetically Modified Mosquitoes In The Florida Keys, Cynthia Taylor

Open Access Dissertations

This dissertation presents a discursive case study of a recent public scientific controversy surrounding proposed field trials of Oxitec’s genetically modified (GM) mosquitoes in the Florida Keys. Despite endorsements by the Florida Keys Mosquito Control District, starting in 2011, and the US Food and Drug Administration’s approval in 2016, field trial releases in the region have been stalled by intense public opposition. The research presented here attempts to better understand the nature of this controversy through a close examination of science communication and public engagement efforts. Avoiding the assumption that resistance to scientific and technological interventions is reducible to a …

A New Physically Motivated Clutter Model With Applications To Non-Destructive Ultrasonic Testing, Yazan Rawashdeh

Open Access Dissertations

The problem of detecting a defect inside the material in an ultrasonic non-destructive testing (NDT) session is addressed in this dissertation. What makes this problem a difficult one is the presence of clutter noise, which is signal-dependent noise. The clutter noise in the material is caused by the microstructure of the material under test. When an ultrasonic wave travels through a coarse-grained material, the traveled pulse hits the grain boundaries, which will cause some of its energy to propagate back to the transducer and mask the echo from the defect if it exists. We tackle the problem by first establishing …