Digital Commons Network^™

Late Quaternary Vegetation And Climate History From The Lake Junín Plateau, Jacob Daniel Schiferl

Theses and Dissertations

Whether the Andean ecosystem is resilient against future climate change remains unclear. A 2018 IPCC special report identified that warming more than 1.5ºC above pre-industrial temperatures by the year 2100 would be a major disrupter to natural systems, by causing more frequent extreme heatwaves, prolonged droughts, extreme precipitation events, and biome shifts. The tropical Andes will likely exceed this 1.5ºC threshold within the next century, threatening the diverse and endemic biota found in one of the world’s largest biodiversity hot spots. Yet few studies have examined the response of the Andean system through past interglacial periods when the temperatures were …

A Computational Model Of Arterial Thrombus Mechanics In Stenotic Channels, Elise Kole Aspray

Theses and Dissertations

Platelet aggregation is one of the major components of blood clotting. The proximal cause of most heart attacks and many strokes is the rapid formation of a blood clot (thrombus) in response to the rupture or erosion of an arterial atherosclerotic plaque. In the context of a stenotic artery (i.e., an artery whose lumen is partially blocked by the plaque) understanding how the thrombus forms presents additional challenges because of the extremely high shear rates and stresses present as a consequence of the constriction. In this dissertation, we use a two-phase continuum model to investigate the stability of an existing …

Characterization Of Ph – Responsive Nanocage Based On The Ferritin Iron Storage Protein, Satyam Singh

Theses and Dissertations

The iron-storage protein ferritin (Ftn) assembles into a protein cage structure with 24 subunits and octahedral (4-fold, 3-fold, 2-fold) symmetry. Each monomeric subunit contains a robust four-helix bundle fold. The fully assembled Ftn structure has a high degree of thermal stability (up to 100°C), a mono dispersed size (12 nm in diameter), and a large central cavity (7-8 nm in diameter). The central cavity stores ferric iron in phylogenetically diverse group of organisms, including humans. The central cavity has been used for encapsulation of cargoes such as other metals, contrast agents for imaging, small molecule drugs for therapy, …

Simulation Of Pituitary Organogenesis In Two Dimensions, Chace E. Covington

Theses and Dissertations

The pituitary gland is a vital part of the endocrine system found in all vertebrates and is responsible for the production of hormones that influence many physiological processes in the organism’s body. Although much has been learned of pituitary organogenesis, studying the dynamics of the cells in the developing pituitary gland is difficult. Pituitary organogenesis has been studied through “snapshots” of a developing pituitary gland by removing and viewing the pituitary glands of different specimens. Thus, how the individual cells in the developing pituitary gland behave and interact with one another is not fully understood. To aid in understanding pituitary …

Experiences Of Five Women Presidents In Higher Education: A Narrative Study, Mary Alexander

Theses and Dissertations

Extensive research has demonstrated that leaders aspiring to become women college presidents encounter many barriers, including gender-based leadership barriers. In higher education, women hold more degrees than men; however, women account for only 30 percent of all college and university presidencies. As the total number of women earning doctoral degrees and hired into faculty positions within the academy increases, the overall gap of the genders begins to narrow (Flaherty, 2016), and women are hired into lower status instructor positions compared to their male counterparts who are in tenured or tenure track position.

Even in presidential positions, women leaders face challenges …

Genetic And Epigenetic Regulations Of Eds1-Mediated Plant Immunity And Identification Of Bacterial Type Iii Effectors Targeting De Novo Dna Methyltransferase Drm2 In Arabidopsis, Ming Zhao

Theses and Dissertations

In Arabidopsis thaliana, Enhanced Disease Susceptibility1 (EDS1) acts as an indispensable hub in plant immunity and is mainly responsible for plant basal defense, systemic acquired resistance (SAR), increase of endogenous content of salicylic acid (SA) and effector-triggered immunity (ETI). Epigenetic regulators play crucial roles in multiple important cellular processes. As one catalytic core of Polycomb Repressive Complex (PRC2), CURLY LEAF (CLF/SDG1) protein promotes H3K27me3 deposition at specific loci for genes repression. In this work, I found that EDS1 interacted with epigenetic regulators SDG1, SDG9, SDG15, SDG22 and SDG35 in yeast two-hybrid assays. The growth of the bacterial pathogen Pseudomonas …

Characterization Of A High Affinity Glutathione Transporter And Its Impact On Glutathione Depleted Saccharomyces Cerevisiae, Tirthankar Bandyopadhyay

Theses and Dissertations

Thiol-disulfide redox homeostasis is integral for maintaining the redox status of proteins and other thiol-containing molecules within the cell. Among the many antioxidants and detoxifying enzymes and small peptides, glutathione (GSH) has proven to be critical for the preservation of function and structural integrity of the cell due to its functionality in areas like oxidative protein folding, thiol redox control, reactive oxygen species (ROS) and xenobiotics removal as well as iron regulation and Fe-S cluster biogenesis. Therefore, our studies are aimed at elucidating the factors that control GSH trafficking and metabolism in the model eukaryote Saccharomyces cerevisiae (baker’s yeast). Using …

Models In Scientific Inquiry, Justin Price

Theses and Dissertations

This dissertation studies how models become useful for scientific inquiry. Towards this study, I develop a theory on the cross-discipline transfer of mathematical models. The first part of this theory characterizes the way in which scientists must respond to the constraints in making a transferable model useable in their discipline. I invent the notion of a landing zone to identify the aspects of their domain that scientists prepare for the use of a transferrable model. The second part connects this response-to-constraints to cases of conceptual progress resulting from model transfer in biology and chemistry. The last part of this dissertation …

Exploring The Relationships Between White Teachers And Black Students: A Qualitative Study On The Impact That Culturally Relevant Pedagogy And Positive Relationships Can Have On Student Success, Lindsay Johnson-Hansen

Theses and Dissertations

This action research study began as a way to investigate the impact of the relationships that White teachers have on their Black students and what strategies can be implemented to promote success in the absence of a positive relationship. Historical information provides the reader with the basic understanding of why academic deficiencies exist and continue to exist in the Black community and what strategies inside and outside of school can remedy the achievement gap. This qualitative study provides information directly from the students who experienced the inequities as told through interviews and an anonymous survey. The lack of diversity among …

The Impact Of Virtual Field Trip Programs On Elementary Students’ Interest In Science Domains And Stem Fields, Jasmin Roberts Poor

Theses and Dissertations

The number of science, technology, engineering, and mathematics (STEM) jobs available in the United States will soon outnumber those qualified to fill them, and there is a decrease in the number of students pursuing STEM careers. Promoting students’ interest is an effective way to influence career choices. Field trips offer students hands-on, experiential learning opportunities that have an impact on students’ interest levels. Yet, not every teacher can take field trips due to logistical, financial, and geographical constraints. Standards-based virtual field trips are a promising strategy to support student interest in science, STEM fields, and meet the educational needs of …

Los Milagros De Santiago Como Sustrato Ideológico En La Formación De Una Identidad Protonacional Castellana, Francisco David Mesa Muñoz

Theses and Dissertations

Saint James Apostle has been historically associated with his predications in the Iberian Peninsula. His cult started in the medieval times and has prolonged until the present, where he is considered the patron Saint of Spain. The construction and promotion of this symbol has been possible thanks to a combined set of efforts, whether premeditated or not, coming from the political and ecclesiastical groups in power. These groups made use of one of the most extended and influential literary genres to lecture and indoctrinate the vast majority of illiterate people during medieval times: the miracles.

In this study, I delve …

Biobehavioral Measurement Of Heterogeneity In Autism Spectrum Disorder, Carla Anne Wall

Theses and Dissertations

Autism spectrum disorder (ASD) is a highly prevalent neurodevelopmental disorder characterized by the presence of social-communication deficits and restricted and repetitive interests and behaviors (American Psychiatric Association, 2013b; Baio et al., 2018). It is characterized by high genotypic and phenotypic heterogeneity, which complicates both diagnosis and treatment efforts (Jeste & Geschwind, 2014; Kim, Macari, Koller, & Chawarska, 2016). Well-studied sources of heterogeneity in ASD include age, sex, intellectual ability, temperament, physiological arousal, social attention, and the presence of genetic syndromes that are highly penetrant with ASD (Campbell, Shic, Macari, & Chawarska, 2014; Harris et al., 2008; Klusek, Roberts, & Losh, …

Exploration Of Vase As An Extraction Method For Emerging Disinfection By-Products And Acidic Methanol As A Safe And Effective Derivatization Method For Haloacids, Madison Leigh Kilpatrick

Theses and Dissertations

This project aims to create an environmentally friendly, robust, and efficient extraction and preconcentration method in both the detection and quantification of various disinfection by-products (DBPs). Vacuum assisted sorbent extraction (VASE) is a newly developed method in the extraction of both volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs). This extraction method is paired with a Thermo Scientific TSQ Quantum Triple Quadrupole GC-MS system for the quantification of DBPs. VASE outperforms current DBP extraction methods, with liquid-liquid extraction (LLE) being the most used alternative, because of its minimal use of solvent, high level of automation, and over-all ease of …

Reimagining Prince Hall: Race, Freemasonry, And Material Culture In Boston, 1775-1870, Sueanna Smith

Theses and Dissertations

This dissertation revisits the subject of early black freemasonry and draws upon a new wealth of archival material to recontextualize it through the lens of social history and print and material culture. This study explores the way that freemasonry operated in the daily lives of black masons and presents a new social history of the formation of Boston’s first black masonic lodge. Turning specifically to print and material culture, it traces the way that the earliest black masons engaged in the broader print and material culture of the society, thus promoting interracial engagement. This study also traces how the Prince …

Uptake, Acuumulation, And Toixicity Of Silver Nanoparticles To Juvenile Bivalve Mollusc’S Hard Clam Mercenaria Mercenaria, Hanaa Radhi Jolan Al Hameed

Theses and Dissertations

Nanoscience and nanotechnology have gained attention in the last 20 - 30 years. Manufactured nanoparticles (NPs), which are defined as having at least one dimension between 1 and 100 nm, are the main products of nanotechnology. Nanoscale materials often have novel properties due to their size and this has made them so attractive for a range of processes and sectors. These attractive properties have enhanced their use in a wide range of consumer products and applications including electronic, biomedical, and pharmaceutical. The overall objective of this dissertation was: 1) to investigate the transformation of well-characterized AgNPs, at environmentally relevant concentrations …

Partitioning Of Volatile Organic Compounds Into The Multiple Environmental Compartments, Jeonghyeon Ahn

Theses and Dissertations

Volatile organic compounds (VOCs) dominate the class of pollutants that accumulate in the atmosphere and indoors. Partitioning coefficient is a measure of a compound’s ability to distribute between two phases. Assessing the partitioning of VOCs is essential to determine their transport, fate, behavior, and adverse environmental and health impacts across multiple environmental compartments. Studies on VOC partitioning have been limited because discriminating the small mass fraction of VOCs in aerosol particles is difficult to quantify. The partitioning of VOCs into soil, air, and aerosol particle phases was investigated under dynamic laboratory conditions. A bench-scale system that precisely controlled the relative …

Accurate And Integrative Detection Of Copy Number Variants With High-Throughput Data, Xizhi Luo

Theses and Dissertations

Copy number variation, as a major source of genetic variation in the human genome, are gains or losses of the DNA segments. Copy number variation has gained considerable interest as it plays important roles in human complex diseases. Therefore, accurate detection of CNVs with data generated by modern genotyping technologies, such as SNP array and whole-exome sequencing (WES), comprises a critical step toward a better understanding of disease etiology. However, current statistical methodologies for CNV detection still face analytical challenges due to numerous genetic and technological factors that may lead to spurious findings. First, existing methods assume the independent observations …

Regulation Of Inflammatory Processes By Tryptamine, Cannabidiol And 2,3,7,8-Tetrachlorodibenzo-P-Dioxin, Nicholas Dopkins

Theses and Dissertations

Host immunity is a complicated system of pro-inflammatory and anti-inflammatory processes that respond to exogenous and endogenous threats to regulate host physiology, inhibit carcinogenesis, and protect from infections. Sustained deviance from normal immunological function occurs due to a variety of factors both endogenous and exogenous, with some factors that can dysregulate host immunity including: genetics, microbiota composition, toxin exposure, age, gender, and smoking. The etiology of inflammatory disorders is both convoluted and complex due to the sheer number of facets regulating host immunity. To better contribute to understanding how immunological dysregulation occurs we focused on how three anti-inflammatory compounds (tryptamine, …

Patients’ Rights, Patients’ Politics: Jewish Activists Of The U.S. Women’S Health Movement, 1969-1990, Jillian Michele Hinderliter

Theses and Dissertations

As the women’s health movement grew out of second wave feminism in the late 1960s, activists demanded women be taken seriously as health care consumers and critics of male-dominated medicine. Health feminists aimed to fundamentally redefine the relationship between patient and practitioner. Jewish women helped found and sustain the women’s health movement, yet their activist identities are often separated from Jewishness in histories of health reform. “Patients’ Rights, Patients’ Politics: Jewish Activists of the U.S. Women’s Health Movement, 1969-1990,” considers the impact of Jewish identity on Jewish activists’ conceptions of social justice while also tracing their significant contributions to women’s …

Diabetes, Anti-Diabetic Medication Use, And The Risk Of Ovarian Cancer, Chantaezia Joseph

Theses and Dissertations

Background- Although ovarian cancer is a rare disease, it is the 5th leading cause of cancer-related deaths among women in the United States. Diabetes is a serious chronic disease that plagues over 436 million adults worldwide and was ranked 7th in causes of death in the US in 2017. Epidemiologic evidence suggests that diabetes may lead to an increased risk of ovarian cancer due to shared risk factors such as sedentary behaviors, smoking and poor diet or through biological mechanisms related to hyperglycemia and obesity, but the epidemiologic evidence yields mixed results. Certain anti-diabetic medications may increase the risk …

Intersection Of Maternal Disability Status, Prescription Opioid Use Before And During Pregnancy, And Adverse Birth Outcomes, Chelsea Lynes Richard

Theses and Dissertations

Nationally, individuals with disability, like those with chronic health conditions, have higher rates of opioid use and misuse and are prescribed higher dosages than those without disability. Because opioid agonists and antagonists can cross the placenta rapidly, there is biological plausibility that they may have an impact on birth outcomes. Therefore, monitoring prescription opioid use, particularly among pregnant women, is of great public health importance. While evidence for the impact of opioid use on preterm birth and low birthweight are conflicting; findings are consistent that opioid use during pregnancy is associated with a higher risk of small for gestational age, …

Household Food Security, Lifestyle Factors, And Glycemic Control Among Youth And Young Adults With Diabetes, Lauren A. Reid

Theses and Dissertations

The purpose of this study was to assess the associations between household food insecurity (HFI) and glycemic control, physical activity, and diet quality in youth and young adults (YYA) with type 1 diabetes (T1D) and type 2 diabetes (T2D). Among older adults, HFI has been shown to complicate diabetes management due to the essential role of diet in diabetes management and the financial stress associated with HFI. Although HFI is more prevalent among YYA with diabetes than the general population, there are only a handful of studies that have focused on this population and, studies that include YYA with T2D …

Colloidal Semiconductor Quantum Dots: Solution Processing And Heterostructure-Based Optoelectronics, Mathew L. Kelley

Theses and Dissertations

Colloidal semiconductor quantum dots (QDs) are attractive candidates for high-efficiency solar cells and uncooled multiplexed photodetectors due to their favorable characteristics including large absorption cross-sections, size-tunable bandgap energies spanning the ultraviolet (UV) to short wave infrared, and solution processability. These QD-based optoelectronic devices operate on the basis of efficient photogenerated charge migration within QD solids and charge separation and recombination at electrical junctions, underscoring the need for (1) processing strategies that facilitate charge transport and (2) characterization techniques that robustly interrogate charge separation at QD interfaces. Here, my work on the post-synthetic processing and surface modifications of several semiconductor QDs, …

Plasmonic Metallic And Semiconductor Nanomaterials, Mengqi Sun

Theses and Dissertations

The earliest account of localized surface plasmon resonance (LSPR) has to date back to the ancient age of Rome in 400 A.D. The famous glass of Lycurgus cup told the story of unique light-and-matter interaction at the nanoscale that confines the electromagnetic field resonance at its surface and therefore allows LSPR feature to noticeably arise. The conventional metallic LSPR nanomaterials, like Au and Ag nanoparticles attract constant attentions due to their synthetic simplicity, chemical robustness, and visible spectral response. Its ability to generate sensitive dielectric sensing of the surroundings, strong electromagnetic field and active charge carriers upon optical excitation triggered …

Characterizing The Temporal And Spatial Distribution Of The Cannonball Jellyfish (Stomolophus Meleagris) In The South Atlantic Bight, Lauren G. Faulk

Theses and Dissertations

The cannonball jellyfish, Stomolophus meleagris, is commercially harvested throughout its range in the tropical and sub-tropical Americas, including in the South Atlantic Bight, where an estimated 4,000 tons (less than 2.4% of the estimated stock in South Carolina during the spring) are harvested annually. Like many Scyphozoan jellyfish, cannonball jellies have high interannual variability and little is known about the environmental drivers of their distribution and phenology. To better understand the ecology of this targeted species, we used fisheries-independent abundance data of cannonball jellyfish from 2001 to 2019 collected by the Southeast Area Monitoring and Assessment Program (SEAMAP) throughout the …

Human Cst (Ctc1-Stn1-Ten1) Promotes Topbp1 Stability And Chk1 Phosphorylation In Response To Telomere Dysfunction And Global Replication Stress, Stephanie Michelle Ackerson

Theses and Dissertations

Genomic DNA is constantly damaged by both internal and external genotoxins and cellular processes. A consequence of unrepaired or misrepaired DNA damage is genome instability, a hallmark of cancer and numerous other diseases. Eukaryotic cells have developed complex mechanisms to repair DNA damage, which is collectively referred to as a DNA damage response (DDR). CST (CTC1-STN1-TEN1) is a heterotrimeric, RPA-like protein complex that binds to single stranded (ss)DNA. In humans, CST functions in the replication and maintenance of telomeres, structures found at the ends of linear chromosomes, as well as non-telomeric DNA. Previous studies showed that deletion of the largest …

Dissolved Nitrogen Cycling In The Eastern Canadian Arctic Archipelago From Stable Isotopic Data, Holly Westbrook

Theses and Dissertations

Climate change is expected to drastically alter the input of inorganic nitrogen (N) sources in the Eastern Canadian Arctic Archipelago (ECAA) with increasing discharge from glacial meltwater and permafrost thawing. Since dissolved inorganic N is generally depleted in surface waters, dissolved organic N (DON) could represent a significant source of nutrients limiting primary production in Arctic ecosystems. Yet, few DON data for this region exist. We analyzed stable isotopes (δ¹⁵N and δ ¹⁸O of DON and NO₃-) to investigate dissolved nitrogen cycling in glacial rivers and marine surface samples collected in the ECAA during summer …

Alkyne Cyclization Involving A Zwitterionic Hexaruthenium Carbido Carbonyl Complex And The Synthesis Of The First-Nitrido Heterometallic Carbonyl Cluster Complexes, Nutan Damodhar Wakdikar

Theses and Dissertations

Chapter 1 introduces two related topics with the primary focus on the background of zwitterions and the conceptual understanding of a metal-complexed zwitterion. It also discusses the potential of a metal-complexed zwitterion for a carbon-carbon bond formation reaction. Synthesis of the metal carbonyl cluster, Ru6(µ6-C)(µ-CO)(CO)16, is also discussed in detail. Then, the background with the importance of heterometallic cluster complexes is discussed with the help of various examples used for catalysis.

The reaction of hexaruthenium carbido carbonyl cluster, Ru6(µ6-C)(µ-CO)(CO)16, with C2H2 and Me3NO yielding first examples of two new zwitterionic complexes, Ru6C(CO)15(μ−η2−C2H2NMe3), 2.2, and Ru6C(CO)14(μ3−η4−C4H4NMe3), 2.3, are presented in Chapter …

Caribbean Yellowtail Snapper Ocyurus Chrysurus: Filling In Critical Gaps In Research For Life History And Novel Ageing Validation Utilizing Δ14C, Sarah Zajovits

Theses and Dissertations

Yellowtail snapper Ocyurus chrysurus is an important fisheries species in the US Caribbean; in waters of Puerto Rico, it ranks second for reef fishes in terms of annual total commercial landings. However, a paucity of information exists concerning basic life history information for Caribbean yellowtail snapper populations. This study provides the first comprehensive documentation of age, growth, and reproductive biology of yellowtail snapper from the Caribbean and is the first to directly validate age estimation in this species. Sampling of 1731 yellowtail snapper occurred in Puerto Rico and the U.S. Virgin Islands during 2013-2021 from fisheries-dependent and –independent efforts. Fish …

Carbon Storage Via Mineral Bonding In Subsoils A Review Of Soil Processes, Kiele Goins

Theses and Dissertations

Soil is an important but often poorly understood portion of the carbon cycle. Soil can store more carbon than twice today’s atmosphere, but the factors that control carbon storage are often unclear. Carbon enters the soil through input of organic matter, erosion, and aerosol deposition and is lost mostly via microbial decomposition. Carbon loss in soil is impacted by the chemical composition of organic compounds, environmental factors, and human activities. Furthermore, as climate changes soil, carbon storage may be vulnerable. Although carbon can be stored throughout soil, carbon storage varies with depth. In topsoil, carbon is stored for short periods …