Master's Theses (Fall 2009 to Present)

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New submissions to the University of Delaware Master's Theses collection are added as they are released by the Graduate College. The Graduate College deposits all master's theses from a given semester after the official graduation date.

University of Delaware master’s theses submitted between 1980 - Summer 2009 are available online through Dissertations & Theses @ University of Delaware. Use the library catalog, DELCAT, to search for all print or microform copies of master's theses 1980 - 2009 that are NOT available in Dissertations & Theses @ University of Delaware because Dissertations & Theses @ University of Delaware does NOT contain the complete collection of University of Delaware master's theses.

Master’s theses in the Longwood Graduate Program in Public Horticulture (now known as the Longwood Fellows Program) submitted between 1970 - 2004 are available online.

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Impact of hydrologic disturbances and water chemistry on soil biogeochemistry in an upland coastal forest
(University of Delaware, 2025) Cruz-O’Byrne, Rosmery
Hydrologic disturbances driven by sea level rise and storm surges are altering biogeochemical processes in coastal forests, transforming upland ecosystems into wetlands. However, the effects of repeated flooding on belowground dynamics during the early stages of this transition are not well understood. This study investigates how repeated hydrologic disturbances with different water chemistries impact soil biogeochemistry dynamics in upland coastal forest soils. We conducted a mesocosm flow-through incubation experiment, applying freshwater (FW) and brackish water (BW) pulses to intact soil cores from a temperate coastal forest previously exposed to these treatments in separate field plots. Continuous measurements of CO2, CH4, and N2O fluxes were coupled with δ13C-CH4 isotopic analysis, porewater chemistry (DOC, SO42-, S2-, Fe2+, Mn2+, NH4+, NO3-+NO2-, ORP, pH), and Fourier-transform infrared spectroscopy (FTIR) of soil organic functional groups. Results showed that BW treatments resulted in stronger legacy effects, enhanced reducing conditions, increased CH₄ and N₂O fluxes, and alterations in soil organic matter. Elevated S2- and δ13C-CH4 signatures indicated the co-occurrence of sulfate reduction and methanogenesis via the methylotrophic pathway. Accumulation of NH4+ and N2O suggested potential dissimilatory nitrate reduction to ammonium (DNRA) and incomplete denitrification. Increases in Fe²⁺, Mn²⁺, and DOC indicated the destabilization of organo-mineral associations, while FTIR analysis revealed changes in soil functional groups, including degradation of polysaccharide structures and incorporation of sulfur- and nitrogen-containing groups. Our findings underscore the vulnerability of upland coastal forest soils to repeated inundation, revealing water chemistry–dependent responses and highlighting the complex biogeochemical feedbacks triggered by brackish water intrusion.
Parsing pulses: testing the limits of temporal phase perception in human vision
(University of Delaware, 2025) Lisech, Andrew S.
Complete information about temporal visual stimuli is available to human conscious awareness at frequencies below about 10 Hz, a threshold known as the Gestalt Flicker Frequency threshold. At faster frequencies, approximately 10–60 Hz, flicker is perceived but the accurate discrimination of temporal phase is not possible. Above about 60 Hz, the Critical Flicker Fusion frequency, stimuli are completely fused and not perceived as temporally varying. To accurately measure temporal phase limits, care must be taken to avoid activating low-level mechanisms that might invoke a perception of motion, which could bely temporal phase. This study explores the temporal properties and neural mechanisms underlying phase discrimination in human vision by examining the impact of interstimulus spacing and hemifield placement on temporal frequency thresholds in a paired achromatic flicker task. Experiment 1 was conducted with binocular viewing and found that narrow interstimulus spacing resulted in higher phase discrimination thresholds, suggesting contributions from low-level motion detection. Wide spacing relied on high-level processing, which led to reduced thresholds. Experiment 2 utilized dichoptic viewing to assess whether low-level motion detection occurs before binocular combination in V1, with findings showing reduced thresholds irrespective of spacing, suggesting that low-level mechanisms were successfully disabled with dichoptic viewing, and that discriminations were instead performed by high-level mechanisms in higher-order cortical areas. Despite the wide range of stimuli that jointly activate these mechanisms due to their overlapping temporal ranges, these results reveal that apparent motion and high-level processing appear to work independently. Once apparent motion is eliminated, thresholds drop to 7–10 Hz. ☐ Keywords: temporal phase discrimination; flicker fusion; psychophysics; visual perception; binocular vision; dichoptic vision; apparent motion
“It's Not A Bad School, It's Just The Teachers”: Understanding The Role Of Teacher Relationships And Culturally Relevant Pedagogy In Black Students’ Perceived Mattering
(University of Delaware, 2025) Shekhar, Sofina
The Black Lives Matter movement has emphasized addressing Black students’ experiences in school and inspired educators and administrators to look beyond test scores to evaluate whether Black students are receiving interpersonal support, feeling integral to their school, and experiencing a sense of “mattering”. The culture gap between the predominately white educator workforce and the increasingly racially, culturally, and linguistically diverse student population raises questions about the efficacy of their pedagogy for all students. By examining Black students’ articulations of their relationships with educators, experiences of culturally relevant pedagogy, and perceptions of mattering, this study seeks to identify practices that facilitate positive school experiences for Black students. The current study explores the educational experiences of five adolescent Black boys, all attending the same urban high school, in a mid-Atlantic state. Data was collected using a qualitative approach to examine their experiences related to school and mattering through semi-structured, one-on-one interviews, and analyzed using a deductive theoretically grounded and inductive thematic analysis-based approach. I found five themes, titled using the participants’ voiced insights, across the participants’ narratives: “They invest in our success”, “They look out for us”, “They humanize us”, “They don’t care about us”, and “We want to reach our full potential”. I discuss the findings in terms of their integration with previous research and theory and explore their implications and directions for future research. This study addresses a critical gap in research by centering the voices of Black students to examine their lived experiences and perspectives on educational practices that directly impact them. It also intentionally foregrounds mattering theory with culturally relevant pedagogy, demonstrating how they are intertwined, and can be used together to better support students. This adds to the body of literature on effective teaching for Black adolescent boys.
Adult American shad Alosa sapidissima habitat occupancy in the Delaware River Basin, USA
(University of Delaware, 2025) Roday, Rachel Ellen
The anadromous American Shad (Alosa sapidissima), a once commercially important species in the mid-Atlantic, experienced population declines due to overfishing, poor water quality, and impediments to accessing freshwater spawning habitat. Regional and national scale efforts substantially addressed the former two obstacles to facilitate population growth, but dam modifications or removal are still ongoing. In 2019, the State of Delaware removed the first barrier to anadromous fish passage on the Brandywine River (a tributary of the Delaware River), Dam 1. Forty-four shad were tagged with acoustic transmitters from 2021–2024 above recently removed Dam 1 and tracked in the Delaware River Estuary and coastal waters of the Atlantic Ocean. The length of available habitat increased by 1.3 km and 68.0% (30/44) of tagged shad used historic spawning grounds in the Brandywine River following dam removal. Thirteen individuals exhibited long-term residency in the Brandywine River from May–June, demonstrating the importance of this newly available habitat to spawning adults. Additionally, one fish returned to the Brandywine River between years, displaying inter-annual spawning site fidelity and iteroparity. I also observed exploratory behavior of eight additional shad that exited and returned to the Brandywine River within the same year. I used generalized additive models with environmental covariates including water temperature, flow rate, lunar phase, tidal cycle, etc., matched to occupancy events of shad that exited and reentered the Brandywine River to explain occupancy events within the Brandywine River. Under the most simplified model, adult American Shad occupancy event presence from the eight individuals was significantly correlated to water temperature, day length, flow rate, and lunar phase, which explained 50-60% of deviance (P < 0.05). I also observed more presence during occupancy events at temperatures of 20°C, a day length of 14.6 hours, and flows between 5.5–12.5 m3 s-1. These conditions represent the preferred spawning conditions within the Brandywine River from 2021–2023 for shad that exited and reentered the Brandywine River, despite displaying low predictive power for hypothetical environmental conditions. As such, these potential environmental preferences should be noted when management entities design dam removal or habitat restoration within northern Delaware, or specifically within the Brandywine River.
Assessing public health disparities: impact of the Beltline Project on the city of Atlanta
(University of Delaware, 2025) Ellingsworth, Isabella
Urbanization has led to the majority of the American population residing in densely developed areas, prompting a critical examination of how limited urban space is utilized. This study investigates the importance of integrating green spaces into urban planning and development to address communities' physical and mental health needs. Drawing on 2010 and 2020 data from the US Census Bureau and the Center for Disease Control and Prevention, this research explores repurposing existing infrastructure into urban green spaces and their potential health benefits. ☐ This analysis aimed to reveal whether urban green spaces, like the BeltLine in Atlanta, Georgia could aid in mitigating poor public health indicators, amongst the population who reside within the city. The Atlanta BeltLine, a 22-mile loop of trails, transit, and greenspace, serves as an exemplary case study due to its diverse neighborhoods and historical railway origins. Initially constructed in the late 19th century and largely abandoned by the mid-20th century, the BeltLine now aims to drive sustainable growth and connectivity. This would be achieved by the green spaces promoting physical activity and encouraging behavior that could improve mental health in residents with access to this green space. By comparing public health data collected by the U.S. Census Bureau and the Center for Disease Control and Prevention, this analysis examined differences in the public health indicators for census tracts in the city of Atlanta for those that do and do not have direct contact with the BeltLine Project. ☐ The hypothesis examines if the tracts with access and direct contact with the BeltLine Projects have better public health outcomes compared to tracts that do not. This study reveals that while all Atlanta census tracts saw health conditions worsen between 2010 and 2020, those with access to the BeltLine experienced a slower rate of decline. Although the changes for most were not statistically significant, the data indicates that green infrastructure could potentially mitigate the deterioration of public health indicators if given more time to work within the community.
Black Insurgency: the long struggle for land and national independence
(University of Delaware, 2025) Newman, Joshua
The goal of Black Insurgency is to intervene in the classical period of Black Power Studies to produce scholarship that argues the perspectives of understudied organizations and activists who were not interested in reshaping American democracy, but rather sought to dismantle U.S. imperialism, colonialism, and white supremacy, in-favor of Black self-determination. Land is the paradigm through which Black Insurgency examines a protracted struggle against domestic colonialism by Black radical organizations. Political violence by these organizations was the mechanism by which an overturning of the colonial order could manifest Black self-determination. Violence against the state was characterized as revolutionary action, necessary to topple the United States as a colonial regime that had been oppressing African-Americans. Organizations like, the Revolutionary Action Movement (RAM), the Republic of New Afrika (RNA), and the Black Liberation Army (BLA), who embodied revolutionary Black nationalism, are either misunderstood or understudied within the field of Black Power Studies. Black Insurgency will intervene into the scholarship on Black Power to argue that not only was resistance as political violence an essential strategy for self-defense, but also a tactical response to the long-standing colonial war against Black America, while in pursuit of a Black nation-state. These revolutionary Black nationalist organizations and activists are ideologically similar in their approach to Black self-determination and demonstrate a central radical response within the Black Freedom Struggle that must be carefully engaged. The analysis of internal colonialism, Third World internationalism, armed struggle, land, and national independence are the politics of anti-imperialism by organizations that wish to dismantle U.S. imperialism internally, while simultaneously achieving national independence.
Washington, Jefferson, & Franklins English ancestors: Northamptonshire and its influence on the founding fathers
(University of Delaware, 2025) Read, Kim
The Thesis examines three founding fathers’ ancestry and why their heritage was the backbone of who they were. George Washington, Thomas Jefferson and Benjamin Franklin’s family hailed from the county of Northamptonshire, in central England, seventy miles north of London. Northamptonshire was known for its religious dissent during the sixteenth and seventeenth centuries. The county also had an abundance of wealth bought through land ownership and favors to the crown. Land enclosure also enhanced the gentry’s wealth. Religious conflict had a profound effect on the families of these three men, leading members of their English Families to move to America. Opportunities to increase wealth through trade overseas and colonization also helped Northamptonshire gentry. The thesis shows how their family history gave them financial and educational advantages not readily available to all settlers that took the journey across the Atlantic to seek a better life. Through the lens of their ancestors, the thesis shows how British History affected Thomas Jefferson’s, George Washington’s and Benjamin franklin’s lives. These men’s family’s journeys gave them the tools and confidence to pursue leadership in North America. Although each founding father’s family had a different story and outcome, they all had similar commonalities. They were all affected by the English Civil War and changes in Leadership. Their family’s status and values of education followed their families to America. Only one of the men acknowledges his English past but there is no doubt their English Heritage helped their families become some of the most important families in colonial history.
Comparison in overnight of speech consolidation between individuals with and without a diagnosis of dyslexia
(University of Delaware, 2025) McSorley, Alexandra Marie
This research study investigated whether adults with dyslexia experience difficulties with overnight memory consolidation across different types of learning. Participants with and without a diagnosis of dyslexia completed three tasks designed to assess declarative memory (object recognition), procedural memory (serial reaction time), and speech-sound learning (discrimination and identification). Each task was administered in the evening and again the next morning to evaluate changes over a 12-hour period. Results demonstrated that declarative memory improved similarly across groups, supporting claims that this memory system remains intact in dyslexia. In contrast, individuals with dyslexia demonstrated weaker overnight retention on the procedural task, suggesting possible consolidation deficits. For speech-sound learning, the dyslexia group displayed greater gains overnight in identification, indicating potential differences in how sleep supports auditory memory. These findings suggest that memory consolidation in dyslexia may be domain-specific and influenced by task type, offering new insight into how sleep-related processes affect learning in this population.
Dual fluorine tag incorporation into SARS-CoV-2 NNTD Protein for 19F NMR spectroscopy
(University of Delaware, 2025) Pedro de Jesus Pereira, João
This master’s thesis describes efforts towards the development and application of a dual fluorine labeling strategy for 19F nuclear magnetic resonance (NMR) spectroscopy. Using the SARS-CoV-2 nucleocapsid N-terminal domain (NNTD) as a model, we combined two labeling techniques: site-specific incorporation of trifluoromethyl-phenylalanine (tfmF) at position Phe-28 and biosynthetic incorporation of 7-fluorotryptophan (7F-Trp) at all native tryptophan residues (Trp-14, Trp-70, Trp-94). High-efficiency labeling (>90%) was achieved in E. coli Rosetta DL3 using orthogonal tRNA/synthetase systems, confirmed by mass spectrometry and SDS-PAGE. ☐ Solution-state ¹⁹F NMR showed distinct and well-resolved signals for both tfmF (−14.6 ppm) and 7F-Trp (−52 to −57 ppm), indicating successful site-specific incorporation with minimal impact on protein structure. Moreover, the CF₃- tag provided approximately 9-fold greater signal sensitivity and can serve as an independent reporter on local structure in 19F NMR experiments. Crystallization and solid-state NMR data confirmed that the dual-labeled NNTD maintained its structural integrity, supporting its use for NMR experiments. ☐ This work lays the foundation for future NMR studies. The methodology is broadly applicable to other systems, offering a versatile framework for atomic-resolution structural biology in physiological contexts.
Distribution of buoyant tracers in an idealized tidally averaged estuarine circulation model with application to the Delaware Bay
(University of Delaware, 2025) McConaghy, Shannon
Between the river and the ocean lies a highly dynamic and complex system, an estuary, that acts as a critical trap for marine debris originating from both land and fluvial sources. In this study, an idealized tidally averaged estuarine circulation model for the gravitationally driven circulation was applied to predict tracer transport and marine debris pathways using a tracer conservation equation that incorporates multiple transport processes. The modeling results reveal that tidal mixing, estuarine depth, and width determine the estuarine circulation strength and structure. Lateral surface flows converge over the deeper channel center aggregating buoyant tracers there. At the bottom of the channel center lateral currents diverge resulting in enhanced tracer concentrations of sinking particles near the estuarine flanks. An analysis of high-resolution satellite imagery of Delaware Bay suggests that buoyant material frequently aggregates near the estuarine channel in narrow bands that extend along the estuary, consistent with model results. These aggregation zones are more often observed during winter than other seasons. Finally, the cross-sectionally averaged tracer concentration of a neutrally buoyant tracer is modeled based on a balance between transport by river flow, along-estuary tidal mixing, and shear dispersion by the estuarine exchange flow. The along-channel distribution of the tracer concentration is controlled by a nondimensional number (a Peclet number) that describes the relative importance of advection by river flow and along-estuary mixing. For stronger mixing, tracer concentration gradients are more constant along the estuary. Together, these insights offer an integrated framework to better predict and manage marine debris accumulation in estuaries.
Prevalence and diversity of avian haemosporidian parasites in North American raptors
(University of Delaware, 2025) Kwasnoski, Laura
Avian haemosporidians are common vector-transmitted parasites that infect birds. Although avian haemosporidians have been studied extensively in songbirds, less is known about haemosporidian prevalence in raptors, particularly in the United States. We used molecular methods to test blood samples collected from raptors at five wildlife rehabilitation centers across the United States for avian haemosporidians. We identified parasites from the genera Haemoproteus, Leucocytozoon, and Plasmodium using a multiplex PCR and determined prevalence by raptor host species and site. Almost half of the raptors tested (47%) were infected with at least one parasite, with Plasmodium detected at the highest frequency (28%) followed by Haemoproteus (21%), and Leucocytozoon (12%). Prevalence of each parasite genus varied among host species. For example, Haemoproteus prevalence was higher in American Kestrels (Falco sparverius), Barred Owls (Strix varia), Great-Horned Owls (Bubo virginianus) than in Bald Eagles (Haliaeetus leucocephalus) or Black Vultures (Coragyps atratus). Prevalence also varied among sites for all three parasite genera. However, we did not detect a species by site interaction effect for prevalence, suggesting that variation in prevalence among raptor species is relatively constant across the region we investigated. This work adds to our understanding of raptor disease ecology at a regional geographic scale. Future analyses will focus on the diversity and distribution of parasite genetic lineages among these host species and sites.
The analysis of ergothioneine biosynthesis in Streptomyces coelicolor M145 with co-inoculation of Triticum aestivum
(University of Delaware, 2025) Pipinos, Alexandra
The market for agricultural biologicals as replacements for synthetic crop chemicals has grown significantly due to their ability to improve soil health while reducing the overall carbon footprint. In particular, biostimulants can enhance crop yield and quality, increase soil microbial activity, and provide other various benefits to support crop productivity. Additionally, a decline in crude protein content in crops—caused by plant breeding, climate change, declining soil organic matter, and changes in environmental legislation— has led to an increased demand for strategies to boost protein levels in staple cereal crops. Ergothioneine (EGT), an amino acid with recognized nutraceutical and micronutrient properties, has gained popularity for its anti-inflammatory and antimicrobial properties on human health. EGT has been studied in relation to cardiometabolic diseases, anti-aging, neurodegenerative disorders, and various other inflammatory conditions. While plants and humans cannot biosynthesize EGT, its production by Streptomyces coelicolor presents as a promising bio-stimulant to support overall plant health and human health. Our study investigates the potential for Streptomyces coelicolor M145 to enhance EGT levels in spring wheat (Triticum aestivum). In vitro analyses quantified intracellular EGT production, under nutrient-rich and minimal nutrient conditions, using a developed cell extract protocol to determine how intracellular EGT levels vary based on condition and time. ☐ Following inoculation of S. coelicolor on T. aestivum roots, EGT was extracted and quantified from plant roots and shoots. Results confirmed successful EGT extraction from bacterial cell extracts and plant tissues. Additionally, a fluorescent confocal microscopy staining and imaging protocol was developed to assess bacterial colonization on T. aestivum and its potential as a root endophyte. As soon as day 5 post-inoculation, microscopy revealed clear colonization of S. coelicolor inhabiting T. aestivum roots, shoots, and internodes.
Soft landings for tough times: the influence of ground cover characteristics on the wandering behavior and subsurface pupation of overwintering Lepidoptera in urban ecosystems
(University of Delaware, 2025) Jonas, Emma N.
North American caterpillars predominately feed on tree hosts, and subsurface pupation among arboreal Lepidoptera is widespread. Therefore, such species are vulnerable to conditions under host trees during the vulnerable wandering and pupation stages. Current landscaping practices may contribute to declines in Lepidopteran diversity and abundance, particularly in compacted soils of urban environments. Understory plant choice and detritus management following land development characterize soil structure. Therefore, dominant cover types, such as turfgrass, may form novel subsurface microhabitats. The goals of this study were threefold: (a) to determine the most frequently encountered substrates beneath trees in the urban and suburban Eastern U.S. by arboreal, wandering Lepidoptera, (b) to test pupation substrate preference and the influence of substrate type, heterogeneity, and compaction on wandering behavior and pupation depth in the lab, and (c) to test for evidence of ecological traps and characterize the most optimal “soft landing” environments for burrowing Lepidoptera by measuring the ecological and management influences of the aboveground-belowground interface on their burrowing success, overwintering survival, and moisture retention. The Google Earth survey showed that turfgrass is the most frequently encountered substrate beneath urban trees. I found strong evidence that Heterocampa pulverea (Notodontidae) pupated at significantly greater depths within mulch and leaves compared to turfgrass. Caterpillars of this species preferred shredded bark mulch the most, and it had the highest rate of immediate pupation. Burrowing time on bare soil increased nearly fivefold compared to mulch and it was the least preferred substrate. Tests of overwintering survival in Anisota stigma (Saturniidae) showed a positive correlation with tree canopy density. Substrate type also significantly influenced emergence rates, with A. stigma showing the highest success in forest remnants, followed by mulch then mature turf. This species’ emergence rate was lowest in layered urban understories, followed by recently established turf, then bare soil. When soil temperature parameters were included in emergence success models with a smaller sample size of this species, daily average temperature range showed a significant negative relationship. Overwinter water retention of A. stigma adults was weakly, positively correlated with the average daily maximum soil temperature and surface pupation, suggesting the use of discontinuous gas exchange for water conservation under stress. Finally, soil compaction, which was negatively correlated with organic matter, and the proportion of bare soil cover were two covariates negatively correlated with burrowing success in A. stigma and Manduca sexta (Sphingidae), respectively. These findings reveal that common landscaping practices likely contribute to urban declines in burrowing Lepidoptera. Evidence of an ecological trap substrate was highest for layered urban understories and recently established turf, which were surprisingly inhospitable compared to forest remnants. Specific strategies such as mulching or incorporating organic soil amendments may be required to restore habitat productivity exemplified by forests. These data emphasize the importance of “soft landing” management beneath moth host plants, which protect and remediate soil health following land development. Social acceptance of ecological landscaping must be cultivated, and the initiative can start beneath the canopy. Future research should include turfgrass-associated disturbances such as foot or mower traffic when examining this substrate’s potential as an ecological trap because of the propensity of turf thatch to promote shallow burrowing.
Identifying the sources of Dissolved Inorganic Carbon (DIC) and Carbon isotopes (δ13C) in the Roosevelt Inlet (Lewes, DE, USA)
(University of Delaware, 2025) Watson, Jordan Anderson
Over the past decade, researchers have studied how climate change alters the oceans, which has made oceans sinks of carbon dioxide (CO2). The release of hydrogen ions (H+) that results from the oceanic absorption of anthropogenic CO2 causes long-term decreases in pH; otherwise known as ocean acidification (OA). Despite its local importance, few studies examine the impacts of tidal variability on the biogeochemistry, particularly CO2 signals, of various endmember waters mixing. Here, we investigate the Roosevelt Inlet (Lewes, DE, USA), where endmembers namely Broadkill River (freshwater), Canary Creek (marsh water), Lewes and Rehoboth Canal (brackish) and Delaware Bay (seawater) mix. Two in situ autonomous biogeochemical sensors (SeapHOx V2 and SeaFET V2, Sea-Bird Scientific) were deployed to collect high resolution timeseries of coastal ocean biogeochemical data coupled with dissolved oxygen to identify biological influences during tidal events along with timeseries of light measured as Photosynthetically Active Radiation (EPAR). On five separate occasions, discrete samplings coinciding with the high resolution time series were also conducted to determine dissolved inorganic carbon (DIC), δ13C(DIC), total alkalinity (TA) and pH. ☐ Results revealed during the August and October sampling periods that low tide DIC was elevated by biological organic matter decomposition from the freshwater and marsh endmembers, producing high values of PCO2, low pH and O2 values while high tide produced lower values of DIC, PCO2, and higher pH and O2 values. In contrast, the sampling periods of December and February showed low values in DIC, PCO2, and high pH and O2 values, indicating the major processes were carbonate dissolution/precipitation, dilution/evaporation and summation of all aerobic processes. The DIC production in the April sampling period was impacted by an influence from photosynthesis that caused a source of higher pH, O2, and lower DIC and PCO2 values that originated from the freshwater endmember. Once endmembers were identified, the Fry (2002) mixing model for the conservative mixing of DIC and δ13C-DIC was applied to indicate the organic carbon source (decomposition) for the DIC. The modeled data resulted in a seasonal effect on δ13C and DIC, where the high-resolution and high and low tide discrete sampling in August and October had values of δ13C driven by S. alterniflora (-13 ‰) decomposition through marshland aerobic respiration rather than sulfate reduction. The December high resolution sampling period was also driven by values of δ 13C from S. alterniflora (-13 ‰) decomposition, while the high and low tide discrete sampling period had δ13C isotopic values driven by the freshwater endmember of Delaware Bay (-10 ‰, Deng et al., 2022) as noted in Fry (2002). The February discrete and high-resolution sampling pointed towards a dampened effect from marshlands with δ13C isotopic values that were driven by the freshwater endmember of Delaware Bay (-10 ‰, Deng et al., 2022). As such, the Fry (2002) conservative mixing model provides the science community another way to predict the source of organic carbon for DIC to other estuaries with similar characteristics. Overall, the present work utilized sensor and discrete sampling of carbon parameters to facilitate an assessment of the performance of the autonomous biogeochemical sensors and to elucidate the source of carbon parameters (DIC, TA, PCO2, pH, δ13C) to the Roosevelt inlet, driven by both tidal and seasonality effects. The high and low tide discrete sampling helped identify endmembers and high-resolution sampling identified daily and seasonal drivers of biogeochemical variability at the Roosevelt inlet, DE using continuous data logging with emphasis on the carbon dioxide system.
The Delaware Atmospheric Plasma Probe Experiment: the flight computer and science instrument subsystem
(University of Delaware, 2025) Khan, Ranyah
This thesis presents the development and evolution of the Flight Computer and Science Instrument Subsystem for the Delaware Atmospheric Plasma Probe Experiment (DAPPEr), a 3U CubeSat mission designed to study ionospheric plasma. The research details two major iterations of these systems, with the first successfully tested on NASA’s RockSat-C sounding rocket mission in 2024, and the second designed for DAPPEr’s planned launch. The work validates these designs through the successful collection of electron density and temperature measurements in the lower ionosphere during the UDIP-4 mission, where data showed strong agreement with the International Reference Ionosphere model. DAPPEr will expand upon this foundation by deploying dual Langmuir probes at 400-450 km altitude to investigate plasma characteristics and spacecraft charging effects by alternating between grounding to the rocket-skin or the Langmuir probes. As the first spacecraft led by a Delaware team, DAPPEr will act as a stepping stone for Delaware’s space program development, while advancing both the scientific understanding of ionospheric plasma through CubeSat-based measurement techniques.
Systematic identification and validation of cyclic nucleotide receptors in bacteria
(University of Delaware, 2025) Arango Gallego, Alejandra Maria
Cyclic nucleotide-based signaling plays a central role in bacterial antiviral defense systems such as CBASS. These systems rely on a diverse array of cyclic nucleotide second messengers (cNSMs) to initiate immune responses upon phage infection. However, the full spectrum of protein receptors that detect these molecules remains largely uncharacterized. This study aims to expand our understanding of cNSM sig-naling, specifically involving cyclic UMP, cyclic UMP-AMP, cyclic GMP-UMP, and cyclic AMP-AMP-GMP, by identifying novel receptor proteins in bacteria and experimentally validating their interactions. ☐ To achieve this, proteomic mass spectrometry analyses were performed on pull-down assays using bacterial cell lysates, with the cNSMs as baits. Candidate receptors were identified based on selective enrichment and further prioritized using bioinformatic analysis. Subsequent biochemical validation involved gene cloning, recombinant protein expression, and purification. Differential scanning fluorimetry (DSF) was employed as a primary screening technique to assess ligand-induced stabilization of protein targets. ☐ Our findings demonstrate that this systematic workflow, combining pull-down proteomics with DSF screening, offers a robust, efficient, and reliable methodology for receptor identification. Importantly, we identified a promising candidate protein that binds cyclic UMP (cUMP), highlighting a potentially novel receptor involved in cNSM-mediated signaling. These results could potentially contribute to our understanding of bacterial signaling networks and regarding the immune regulation mechanisms.
The utilization of boron-rich clusters as aids to detect reactive oxygen and nitrogen species through non-fluorescent modalities
(University of Delaware, 2025) Welch, Casey Madison
Reactive oxygen and nitrogen species (ROS/RNS) are small, highly reactive, and transient oxygen/nitrogen containing compounds that play important roles in redox signaling processes to maintain cellular homeostasis. Typically, these finnicky species are detected through activity-based sensors (ABS) which produce a fluorescent response after being selectively uncaged by the target analyte. However, these fluorescent scaffolds are limited by their large absorption and emission profiles. Therefore, to expand our ability to detect these species, our lab aims to develop and characterize this new class of activity-based sensors to detect these species via non-fluorescent imaging modalities utilizing boron-rich clusters. These boron-rich clusters have unique, tunable properties that are advantageous for alternative based imaging strategies such as time-of-flight mass spectrometry (ToF-SIMS) or Raman spectroscopy. Utilizing these non-fluorescent scaffolds, we hope to expand the toolbox ROS/RNS targeting scaffolds to further understand their behavior within biological systems. ☐ In Chapter 1, I will discuss progress made towards the synthesis and photophysical characterization of this novel class of ABS scaffolds. A strategy to attach a boron-rich cluster to a known fluorescent scaffold was developed. These new dye derivatives were then characterized through UV-Vis and fluorescence spectroscopy to observe how the addition of the cluster impacted the dye’s photophysical properties. Additionally, multiple formylations of these unique dyes were attempted and screened for optimal conditions. An alternative synthetic route is proposed to bypass obstacles and limitations within the current pathway. ☐ In Chapter 2, I will discuss preliminary studies which demonstrate the viability of these boron-rich cluster compounds for alternative imaging strategies in biological systems. A protocol to reliably prepare cells for ToF-SIMS analysis was developed. Using this method, a cell sample was imaged via ToF-SIMS for the first time at the University of Delaware. Building off these preliminary experiments, cells were incubated with a dye conjugated to a boron-rich cluster then analyzed via fluorescence microscopy and ToF-SIMS. Shortcomings of the current strategy are discussed alongside potential solutions to troubleshoot complications encountered in follow-up experiments.
"Truth fighters with no vestments": religion, Fúnmiláyọ̀ Ransome-Kuti and women's resistance in Ẹ̀gbá land, 1930-1950
(University of Delaware, 2025) Dada, Olorunfemi
This study examines the religio-historical dimension of Ẹ̀gbá women's resistance to colonialism from 1930 to 1950. Studies have considered the Ẹ̀gbá women's resistance led by Fúnmiláyọ̀ Ransome-Kuti. However, little consideration has been given to the religious dimension of the Ẹ̀gbá women’s resistance. Primary and secondary sources confirm that women were actively involved in Yorùbá public spaces during the pre-colonial period. However, during the colonial period, women were relegated, made passive, and unrepresented, and their welfare was neglected and oppressed by the colonizer and traditional ruler in Ẹ̀gbá land. This thesis employs Terence Ranger's theory of the invention of traditions to examine how colonial, exploitative, and rigid traditions were invented, the impact of these invented traditions on Ẹ̀gbá women, and Ẹ̀gbá women's resistance against the imposition of taxes and discrimination. Theory of African womanism by Chiwenye Okonjo Ogunyemi and concept of prophethood by Pious Abioje were also employed to argue that African Traditional Religion and culture were potent agencies in the Ẹ̀gbá women's resistance, and women were active agitators against colonialism in Nigeria. This study contributes to research on African Traditional Religion and women's roles in resisting colonialism.
"Prophetic pins": sentiment and sensation in layette pincushions, 1760-1840
(University of Delaware, 2025) Bradshaw, Lauren
In the late-eighteenth and early-nineteenth centuries, layette pincushions were a common gift for expectant mothers either during pregnancy or just after the birth of the child. Created by a family member, friend, or neighbor, they would often be included as part of a layette set which is a collection of clothing and other items needed for the care of a newborn baby. Pins were heavily used by women in the eighteenth century for pinning babies’ diapers, headgear, clothing, and swaddling. These objects were typically marked with the initials and birth date of the child and included phrases such as “Welcome Little Stranger” and “God Bless the Babe and May It Live.” These words took on anticipatory and contingent significance as they would often be created before the birth of the child and would entirely shift in meaning if either the mother or the child did not survive the birth, which was a common occurrence during this era. As the messages and motifs are formed using the exposed pin heads as a design element, the aesthetic and sentimental value must be sacrificed by removing the pins to use them as fasteners. ☐ The practice of materially marking initials and dates on domestic textile objects is rooted in the needlework practices that women would have learned at an early age, beginning with embroidery samplers. Layette pincushions exemplify the material skills and moral values that early needlework education instilled in women as well as directly representing the significance of their assigned roles as mothers. Throughout women’s history the needle has been portrayed as both an instrument of suffering and reclamation as it represents the history of women’s oppression but also their ability to transcend these prescribed roles and gain a greater degree of autonomy. Directly related to the needle, the pin also contains a multitude of dualistic qualities. Opposed to the notions of care intended by these objects, layette pincushions also retain an inherent quality of violence. In addition to their ability to join or mend, pins can also cause pain, which was unfortunately a common occurrence for babies getting stuck with their own diaper pins prior to the invention of safety pins in 1849. ☐ Due to their unique materiality and distinct function, layette pincushions are valuable historical repositories of eighteenth-century craft, culture, and maternal identity. Women in the eighteenth century continuously crafted textile objects by hand that are imbued with sentimental value and continue to serve as mnemonic devices to fill the absence of loss. Existing at the intersection of material culture, the history of emotions, sensory history, and women’s history, this thesis seeks to draw out the relationships between the sensory experience and sentimental emotion of materially marking familial relationships with the shifting temporalities of anticipatory, commemorative, and memorial objects.
"Whatever it is, serve it in glass!": color, gender, and class in pressed-glass tableware, 1925-1945
(University of Delaware, 2025) Titus, Graham
This thesis explores colorful pressed glass tableware produced in the United States from 1925 to 1945, objects that illuminate an intersection between industrial innovation, consumer culture, and working-class domestic life. This period covers the pressed-glass tableware industry’s response to the 1925 Exposition Internationale des Arts Décoratifs et Industriels Modernes in Paris with the introduction of colorful, pressed glass tableware set. The project follows an arc through the peak of pressed glass’ popularity in the 1930s through the collapse of demand for colorful pressed tableware in the United States by the end of World War II. By studying these mass-produced objects, this paper examines how working- and middle-class women deployed material and color to craft domestic identities, embody personality and emotion in the kitchen, and mediate their relationship with household labor. ☐ This project begins by outlining technological advancements in glass production in the nineteenth century, particularly the development of mechanically aided pressing which transformed the industry and democratized access to glass. The resulting “glassification” of lower-income consumers implicated pressed glass directly in the inculcation of aspirational consumer groups into larger American value systems emphasizing tradition and history. While pressed glass mimicked expensive cut crystal at the turn of the twentieth century, this thesis argues that during the peak of its popularity in the 1920s and 1930s, companies in the upper Ohio River Valley produced innovative and distinctly modern glass tableware. Parallel to this changing industrial output, lower-income women developed a unique aesthetic language and use for these objects that challenged conceptions of good design and taste originating from wealthy consumers, deploying color and glass to alleviate drudgery and express satisfaction, comfort, and joy in their kitchens and dining rooms. ☐ Drawing on consumer advertising, shelter magazines, and an abundance of material culture evidence, the research demonstrates how glass manufacturers responded to diverse market demands among non-elite consumers. Companies like Fostoria and Heisey positioned their products at the intersection of modernity and tradition, creating forms that spoke to changing American dining practices and domestic spaces. This paper argues that their colorful glass enabled women to imbue gendered household tasks and spaces, especially the kitchen and dining room, with explicitly positive associations. Rather than viewing these mass-produced objects as cheap imitations of elite goods, this work reframes them as emblems of a “joyous materialism” through which women exercised agency, creativity, and care. ☐ The study concludes by examining how external forces created gendered narratives for glass tableware and its socially appropriate uses, arguing that post-war male consumers rejected color and mechanical production due to their explicit associations with female consumers. This analysis illuminates broader themes about gender, class, and consumer culture in early twentieth-century America, while offering new perspectives on how mass-produced objects served as tools for individual expression and identity formation.

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