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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Developing stable plasmid transformation techniques for anaerobic gut fungi
(University of Delaware, 2024) Khim, Kunwoo
Lignocellulosic feedstock degradation is a critical process in acquiring sustainable fuel and high-value chemicals. Anaerobic gut fungi (AGF), microorganisms residing in herbivore guts, have promising potential in the lignocellulose biodegradation process, because of their distinctive plant carbohydrate binding and biomass degradation ability through multiple carbohydrate-activating enzymes and their assembly into fungal cellulosomes that synergistically enhance biodegradation rates. Although there has been a successful attempt to develop a genetic engineering toolkit for transforming gene cassettes into an AGF system, CAZyme expression through this system was never investigated, and it is also transient, relying on periodic DNA dosing. ☐ Hence, we attempted to improve this pre-developed genetic engineering technique for AGF. First, we tried expressing CAZymes through this system. At the same time, we investigated candidate sequences that would support autonomous replication of gene cassette on AGF, ranging from yeast 2-micron plasmid, Neocallimastix giraffe GF-Ma genomic DNA library, and random AT sequence library. Although we were not fully able to confirm the expression of CAZymes through the current AGF transformation platform, we confirmed that out of 3 candidate sequences, yeast 2-micron plasmid exhibits longer and higher expression of proteins compared to the current transformation platform for AGF, opening the possibility for further research.
Rhythm & roots: Black and insurgent ecologies of orisha music
(University of Delaware, 2024) Graham, Chad Kehinde
Lukumi people reconstructed their ritual music tradition from Yorùbáland in Cuba through the improvisation of their ecology or ecophilosophy. Although Cuba presented a set of environment conditions different from those of the Bight of Benin and Spanish colonists tried to impose a discordant relationship between them with the land, Yorùbá people developed a harmonic and improvisational relationship with the environment on their own terms. Through historical analysis, content analysis of orisha songs and material analysis of the accompanying instruments, this work considers what and who the environment was to orisha devotees. They reaffirmed their commitment to the natural world through the performance of their ritual music, in opposition to the terms of order that produced them to property, thus revealing a cyclical relationship between the material world and sound. That relationship was essential for the reconstitution of the instruments, rhythms and sounds which their ways of knowing required.
Verifiable encrypted computations
(University of Delaware, 2024) Ahmed, Omar Atef Abdelaleem
The ubiquitous usage of cloud computing has revolutionized the way individuals and organizations access and process their data. By delivering numerous services on the internet, cloud computing allows users to store vast amounts of data and perform heavy computations on them without the need to manage complex local computing resources. This innovative technology offers scalable, cost-efficient, and flexible access to storage, computing resources, and applications. Moreover, cloud computing allows businesses to deliver their products and services easily and effortlessly across the globe. ☐ Given that widespread usage of cloud computing and the instrumental development to the world, cloud servers are an alluring target for cyber-attackers who seek to eavesdrop on or steal users’ sensitive data. The providers of cloud computing are also another threat, where malicious cloud providers can access users’ confidential information for their own benefit, such as targeting users with advertisements. ☐ One solution to these concerns is using cryptography. Cryptography is a way to protect our data by transforming them into unreadable form that prevents unauthorized entities from accessing our data. It works well when users want to protect their data when stored on remote servers or during communication. However, this traditional cryptography falls short when we need to perform computations on the data. In this case, a user will have to reveal his encrypted data to the cloud provider to allow performing the computations on them. ☐ To address the shortcomings of traditional cryptography. People tend to use another form of cryptography called Fully Homomorphic Encryption (FHE). FHE allows performing computations on encrypted data, without the need to reveal them. In this thesis, we propose frameworks that enable non-experienced users to seamlessly use homomorphic encryption techniques to securely outsource computations to untrusted cloud providers. Furthermore, we complement this by adding the integrity component, Zero-Knowledge Protocols, so that users can verify the correctness of the computations performed, thus protecting against cheating providers. Moreover, this thesis investigates the design of new optimized functional units to allow users to perform non-linear operations on encrypted data.
The impact of high dietary glucose on amyloid-beta proteotoxicity in Caenorhabditis elegans
(University of Delaware, 2024) Kerslake, Emylee Ann
Alzheimer’s disease (AD) is the leading neurodegenerative disorder worldwide, with an estimated 60 million individuals currently afflicted. Pathological features of this debilitating condition include amyloid-beta (Aβ) accumulation, bioenergetic defects, increased oxidative stress, and impaired glucose metabolism. Since there is currently no disease-modifying treatment for AD, it is essential to understand how modifiable risk factors such as diet impact disease onset and progression. It is difficult to determine the impact of specific nutrients in humans due to complex diet, organismal complexity, genetic diversity, and indirect effects of the gut microbiome. Individuals with abnormal blood sugar levels and glucose utilization are at greater risk for AD, likely because glucose is required to fuel neuronal function. Yet we lack an understanding of how the interplay between glucose and other macro/micronutrient availability impacts brain health. To investigate the effect of excess sugar on amyloid-beta proteotoxicity, I used a transgenic strain of C. elegans expressing the toxic human Aβ1-42 peptide in the body wall muscles, which produces AD-like pathogenic features such as a time-dependent paralysis that mimics progression of the disease, reduced ATP levels, and increased reactive oxygen species. We discovered that glucose supplementation accelerated paralysis in Aβ animals that consumed OP50 E. coli yet had no effect on worms fed HB101 E. coli. While vitamin B12 can protect against Aβ-induced proteotoxicity, B12 is not the factor in the HB101 diet that nullifies the toxic effects of excess glucose levels. To determine how this diet was protective we performed RNA-Seq and observed downregulation of the predicted facilitated glucose transporter F14E5.1 (fgt-2) in animals fed HB101. Loss of fgt-2 slowed Aβ-induced paralysis, alleviated bioenergetic defects, and reduced ROS accumulation in Aβ animals fed OP50. In the presence of excess glucose, the fgt-2(tm3206) mutation abrogated accelerated Aβ-induced paralysis, resulting in a similar time to paralysis regardless of the diet consumed. These findings suggest that fgt-2 impacts Aβ-induced proteotoxicity, potentially by modulating glucose metabolism via glucose transporter availability. However, fgt-2 is not the primary glucose transporter in C. elegans, and its function is not entirely known. In order to further investigate the significance of glycolytic transport in Aβ-induced proteotoxicity, I crossed the Aβ transgene with fgt-1, the primary glucose transporter. Loss of fgt-1 resulted in an accelerated time to paralysis, suggesting the importance of the role glucose import plays. Loss of both fgt-1 and fgt-2 produces a similar result to the fgt-1 single mutant, indicating that either the protective effects of fgt-2 rely on fgt-1 or the function of the primary glucose transporter is crucial regardless of protection elsewhere. Overall, my research highlights the importance of glycolytic transport for overall well-being while demonstrating the impact excess sugar intake has on disease pathologies.
Effects of climate change and food waste policy information on students' attitudes and behavior
(University of Delaware, 2024) Rahman, Md Abedur
Every year in the US, 30 to 40 percent of edible food is wasted, generating 4% of overall greenhouse gas (GHG) emissions. It is estimated that university and college students, particularly those living on campus and using dining facilities, generate approximately 624,371 tons of food waste (FW) annually, contributing to GHG emissions. In response to the economic and climate change impacts of FW, the US government in 2015 announced a FW-reduction goal to cut FW by 50% by 2030. Using before and after surveys, this study investigated changes in the University of Delaware (UD) students’ perceptions of FW generation in dining halls, homes, and restaurants following exposure to information on either the climate change impacts of FW or government FW policy. Using non-parametric Wilcoxon signed-rank tests and Ordinary Least Squares (OLS) regression models, the study assessed changes in perception of students’ self and others’ FW generation and factors affecting those perceptions. Following the government FW policy intervention, students' perception of their own and others’ FW generation decreased in the university setting, and the climate change informational intervention reduced students’ perception of others’ FW generation at home. A decrease in the perception of others’ food waste generation indicates how people expect others to react to the same information. Along with changes in perception of FW generation, the study also revealed changes in students’ FW-related attitudes and knowledge of the climate change impacts of FW, due to the survey and informational interventions. However, the information interventions did not increase students’ willingness to accept (WTA) FW reduction initiatives in the dining halls. OLS models revealed varying impacts of demographic variables such as gender, age, income, membership of environmental organizations, and dietary habits on students’ perception of self and others’ FW generation in different settings. It also revealed the impacts of environmental concerns and the perception of the responsibility of dining halls on students' self and others’ FW generation perception. The OLS model revealed that only female students and students from urban communities significantly reduced their perceived FW generation at home after the informational interventions. Results indicate the effectiveness of climate change impacts and government FW policy intervention in FW reduction among university students. As those interventions affected students’ knowledge, behavior, and perception of FW generation- they could be used to target FW reduction among the students, particularly in the university setting.
Characterizing the devastating rice blast fungus, Sagnaporthe oryzae and a potential biocontrol agent, Bacillus velezensis strain S4
(University of Delaware, 2024) Wockenfuss, Anna
Plant diseases caused by fungal pathogens cause severe problems for agriculture as they greatly reduce crop yield, with some species causing up to 100% crop loss. Managing these fungal plant pathogens are of the utmost importance as the global economy and crop production relies heavily on cereal crops such as wheat, rice, maize and barley. Traditional methods in mitigating fungal pathogens, typically including fungicides, are ineffective against certain pathogens that have developed resistance, an example of this being the rice blast fungus, or Magnaporthe oryzae. M. oryzae kills enough rice to feed 60 million people per year, and thus has become a focal point in the field of plant pathology, where it is regarded as a model organism. Since the usage of fungicides in this instance is not effective, scientists must look for alternatives and now favor the use of biological control agents (BCAs), an environmentally friendly way of disease management. Common BCAs are found within the bacterial genus, Bacillus, which act as a plant growth promoting bacteria (PGPB). Bacillus velezensis strain S4 was isolated and sequenced from biochar-amended agricultural soil in Delaware. Upon genomic analysis and plate assays, B. velezensis strain S4 putatively encodes antifungal compounds, and enzymes including cellulases and proteases. M. oryzae in the presence of B. velezensis strain S4 displays hyphal lesions, reduced radial growth, and decreased appressorium formation, all of which could affect its pathogenicity. RNASeq analysis of this bacterial-fungal interaction revealed 69 differentially expressed genes (DEG) in M. oryzae, including toxin biosynthesis. All together B. velezensis strain S4 shows potential as a BCA for M. oryzae; observing specific aspects of this interaction could yield more insight into how fungi defend themselves against bacteria.
Improving stormwater infiltration with pneumatic air fracturing
(University of Delaware, 2024) Osei Tutu, Nana Abena Konadu
Infiltration basins are one example of stormwater infrastructure where infiltration must be maintained for the system to perform as designed. Unfortunately, sediment buildup and sometimes low-permeability native subsurface geological media within a few feet of the ground surface impede operation. When infiltration capacity is limited, pneumatic air fracturing may improve and maintain sufficient stormwater infiltration and, in some cases, encourage plant root growth. Here, we evaluate the utility of pneumatic air fracturing to remediate stormwater infiltration basins that drain poorly. Pneumatic air fracturing was conducted in 2020 and 2022 at two basins managed by the Delaware Department of Transportation. Using side-by-side control and treated sections, short and long-term improvements (0 – 33 months) in media properties and stormwater infiltration were assessed at shallow and deeper depths (0 – 100cm) using dynamic cone penetrometer, saturated hydraulic conductivity, and dyed water infiltration tests. Results indicate that pneumatic air fracturing significantly reduces the effects of compaction, resulting in an immediate reduction in soil penetration resistance of 67 ± 9%. Saturated hydraulic conductivity also increases, and while these increases diminish with time, they are 100 ± 30% after 12 months. However, these benefits are primarily at > 20 cm depth, at least at these test sites. For both basins, pneumatic air fracturing fixed the perpetual water-logged surface conditions that diminished basin performance. This is the first application of decompaction with pneumatic air fracturing to infiltration basins to increase stormwater infiltration in the US. We discuss the possibility of using similar pneumatic air fracturing on other infiltration basins where the loss of infiltration capacity is a concern.
Material characterization and fatigue lifetime prediction of a reinforced PEM fuel cell membrane
(University of Delaware, 2024) Roosevelt, Rosch
Proton Exchange Membrane (PEM) fuel cells are pivotal in advancing clean energy technologies due to their high efficiency and minimal environmental footprint. However, a significant barrier to their widespread adoption is the durability of the fuel cell membrane, which degrades both mechanically and chemically during regular operation. The mechanical degradation is largely correlated to the repeated swelling and deswelling of the membrane due to varying hygrothermal loads. The introduction of a composite membrane by inserting an inert reinforcement layer has improved its chemical and mechanical stability. This study investigates the factors influencing reinforced membrane failure due to mechanical degradation in PEM fuel cells under different environmental conditions. ☐ This thesis encompasses a detailed material characterization of the membrane to understand its viscoelastic-elastoplastic and hygrothermal expansion properties. Additionally, a water transport model was developed to incorporate the spatio-temporal distribution of water in a membrane. Building on this, a representative volume finite element model of a Fuel Cell stack was created to predict the fatigue crack initiation of the membrane due to a pre-existing catalyst layer flaw. This was done by calculating the plastic dissipation energy (PDE) accumulation in a membrane in the vicinity of a flaw, under fatigue loading. The theoretical predictions were compared with experimental data to validate the model. The effects of temperature, humidity and clamping pressure on the PDE accumulation were examined. The findings highlight the importance of optimizing operational parameters to enhance the longevity of PEM fuel cells. ☐ This work contributes to the development of more durable PEM fuel cells by providing insights into the mechanical behavior of the membrane under various operating conditions. The implications of this research can have a positive impact on improving fuel cell reliability, thus advancing the feasibility of PEM fuel cells for commercial and industrial applications.
Template induced assembly and sequential growth: new mechanisms for the growth of bundlemer nanorods and brushes
(University of Delaware, 2024) Langenstein, Matthew G.
Proteins are incredibly complex materials. These sequence-defined polymers are capable of assembling intro incredibly specific nanostructures through a complicated interplay of physical and covalent interactions. Due to a combination of the large combinatoric space and redundancies amongst the 20 natural amino acids, complete de novo design of fully folded proteins to form specific 3d structures is not fully realized. While the de novo design of proteins is currently out of reach, it is possible to computationally design new smaller polypeptides based on well understood protein folding motifs. One of these motifs, the coiled coil, is particularly well suited for computational design. ☐ Bundlemers are a series of computationally designed coiled coil forming peptides that fold into approximately 2nm x 4nm cylindrical nanoparticles in water. By adding click chemistry functional groups to the N-termini of the bundlemers, it has been previously shown that they can be used as monomers in a A-A B-B step growth like polymerization. The resulting bundlemer nanorods show extremely high aspect ratios and remarkable stiffness. ☐ In my dissertation, I studied new methods for producing high stiffness bundlemer nanorods and developed new methods to bind bundlemers to inorganic substrates. I expanded on the “bundlemers as monomers” approach by developing two new synthesis pathways, sequential growth and template induced assembly. ☐ Sequential growth forms macromolecular grafting-from bundlemer brushes by growing bundlemer nanorods from a surface, one bundlemer addition at a time. Studying this approach on colloidal gold nanoparticles, I grew monodisperse bundlemer brushes with high grafting densities and well-defined quantized lengths based on the number of bundlemer additions. Expanding this work to include flat substrates, I found that the grafting density of single layer bundlemer brushes was heavily dependent on the electrostatic interactions between bundlemers and that neutrally charged bundlemers had denser grafting compared with more highly charged bundlemers in the same solution conditions. ☐ Template induced assembly takes a different approach to bundlemer nanorod growth. Instead of using two folded and stable bundlemer building blocks, template induced assembly used a folded polypeptide bundlemer as a structural template to induce coiled coil formation in a disordered oligopeptide computationally designed to form a coiled coil. When the disordered oligopeptide was conjugated to the N-terminus of the template bundlemer, it quickly folded into an anti-parallel homotetrameric coiled coil, driving supramolecular polymerization into bundlemer nanorods. Both step-growth and template induced bundlemer nanorods formed large continuous α-helices based on their CD spectra and formed high stiffness nanorods based on TEM.
Words have meaning: assessing language choice by American print media in coverage of the opioid crisis
(University of Delaware, 2024) Loughlin, Emily M.
Discussions of opioid use disorder are frequently filled with stigmatizing language that both illuminates and colors the perceptions of opioid use and those living with opioid use disorder. Print media is an important and longstanding source of health information for much of the population, however, it has the potential to implicitly and explicitly endorse biased language related to this national epidemic. These biases may impact the choices made by public health and policy decisionmakers regarding support systems and criminalization of opioid use, having a large impact on outcomes experienced by those with opioid use disorders. This study utilizes aspects of media content analysis to characterize the language choices made by the New York Times, the Chicago Daily Herald, the Saint Louis Post Dispatch, the Richmond Times Dispatch, the Dayton Daily News, the Philadelphia Inquirer, and the Pittsburgh Post Gazette in a random sample of 237 articles published between 2010 and 2020. In this sample, neutral language became more common in coverage between 2016 and 2020, the word “crisis” became more prevalent with the word “epidemic” closer to and following the 2017 declaration of opioid use as a public health emergency. McGinty et al (2016) suggested that coverage between 2000 and 2010 shifted from placing opioid use as a criminal issue to a public health issue and this study supports that this balance was maintained in the following decade.
The role of emerging hosts in the North American emerald ash borer invasion: Implications for natural enemy-free space
(University of Delaware, 2024) Callahan, Heather L.
The invasive emerald ash borer (EAB) has been inflicting catastrophic damage on North American ash resources for over two decades. In its native range, EAB is a secondary pest of Manchurian ash (Fraxinus mandshurica), attacking and killing stressed trees. In North America, EAB’s host range has expanded to include healthy trees of every Fraxinus species encountered, most recently Oregon ash (F. latifolia). Successful EAB development has also been reported on two non-ash hosts: white fringetree (Chionanthus virginicus) and European olive (Olea europaea). However, little is known about how EAB interacts with these novel hosts for development or how natural enemies respond to EAB developing on these novel host plant species. The objectives of this study were threefold: (a) to determine the ability of Oregon ash, white fringetree, and European olive to support complete EAB larval development, (b) to assess the responses of larval parasitoids to EAB developing in these hosts, and (c) to observe how these factors interact to determine EAB net population growth rates on novel hosts. We conducted laboratory and field infestations of Oregon ash, white fringetree, and European olive bolts and trees, comparing EAB larval size and survival on each species over time. We also assessed the responses of larval parasitoids to EAB developing on novel hosts in laboratory exposures and field infestations. We found that Oregon ash is a suitable host for EAB, with no difference in larval size, development, or net population growth rate when compared with EAB developing on green ash. We also found that larval parasitoids Spathius agrili, Spathius galinae, and Tetrastichus planipennisi can find and attack EAB developing in Oregon ash. In contrast, larvae developing on white fringetree and olive died earlier and were smaller than larvae developing on ash. Though there was no evidence of larval parasitism in these non-ash hosts, net population growth rates were close to 0 on both, indicating that EAB populations on these species are unlikely to be self-sustaining.
Synthesis of pseudoindoxyls by asymmetric aza-Heck cyclization
(University of Delaware, 2024) Li, Zeming
Pseudoindoxyl is a nitrogen-containing compound and a kind of the indole derivatives. Numerous natural alkaloids with versatile biological activity contain pseudoindoxyl carbon skeleton. The complex structure of pseudoindoxyl has motivated chemists, prompting the exploration and refinement of various synthetic methods. However, relatively narrow substrate scope extremely limits their application to total synthesis of natural products. Our group is dedicated to develop aza-Heck reaction into various circumstances and we found aza-Heck can be utilized in synthesizing pseudoindoxyls under excellent yield and ee to obtain desired chiral structure. In this document, I will first introduce some well-developed methodologies all over the world and then demonstrate our group and my contribution in the development of pseudoindoxyls syntheses via aza-Heck cyclization.
Occupancy of breeding sika deer populations and competition with white-taile deer on the Delmarva Peninsula, USA
(University of Delaware, 2024) McBride, Matthew
Sika deer were introduced to the Delmarva Peninsula in 1916 and have become an important game species, cultural icon, and agricultural pest. Although sika deer bring many economic benefits to the Eastern Shore, their ongoing range expansion, potential distribution, and impacts on native species are poorly understood. My objectives were to 1) identify landscape characteristics that predict occupancy of breeding sika deer populations in order to assess potential range across the Delmarva Peninsula and 2) assess whether competition with sika deer impacts white-tailed deer. I used trail cameras baited with 11kg of corn to survey 100 sites in Dorchester, Wicomico, and Somerset counties in Maryland during the winters of 2022, 2023, and 2024. Sika deer occupancy probability increased with increasing forest or marsh cover at the 161 ha scale (95% CI 0.015, 0.056). An index of sika deer abundance was negatively associated with an index of abundance for white-tailed deer (95% CI: -0.099, -0.039), white-tailed deer detection probability (95% CI: -0.096, -0.131), and occupancy probability (95% CI: -0.57, -0.13). Sika deer will likely colonize southern portion of the Delmarva Peninsula, characterized by extensive forest and marsh cover and high connectivity. Highly suitable patches set within the agriculturally dominated northern half of the peninsula may lack the connectivity required for sika colonization. Sika deer likely cause declines in sympatric white-tailed deer populations but agriculturally dominated landscapes may act as refugia for white-tailed deer and population management may facilitate the coexistence of both species.
Impacts of biochar on phosphorus distributions in salt marsh surface soils in Delaware
(University of Delaware, 2024) Edris, Pamela
Salt marshes store nutrients, including phosphorus (P) in their soils thereby providing the ecosystem service of reduced nutrient export to estuaries. Contrasting other ecosystem services, nutrient storage may be enhanced in stands of the invasive common reed, Phragmites australis (hereafter Phragmites), compared to native marsh grasses. Restoration efforts to remove Phragmites may thus reduce marsh P storage and allow more P into coastal waters where it can contribute to eutrophication. Prescribed burning to control Phragmites introduces biochar which, due to its surface chemistry and high surface area, may increase the sorption and storage of P in salt marsh soils and recoup this service. To study this P storage potential, cores were collected from 3 Delaware marshes with different burn histories for analysis of organic and inorganic P contents (OP, IP). These P components were also measured in field incubation plots with and without biochar addition in both native and invasive grass stands to further investigate the impact of biochar and plant species on soil P distributions. Because P form influences its aqueous mobility and storage potential, samples were further differentiated for P speciation on a continuum of mobility/lability (immediately plant available/labile, easily exchangeable, intermediately exchangeable, recalcitrant). P composition and distribution were examined for relationships with depth, tidal cycles, elevation, nutrients, pH, and organic and black carbon concentrations. Total and recalcitrant forms of P were expected to be highest in previously burned marsh environments and the biochar amended plots demonstrating a P storage ecosystem service provided by the biochar inputs. Further, P concentrations were expected to be higher in the soil of Phragmites stands compared to Spartina. Neither burn frequency nor biochar application demonstrated a relationship with total organic or inorganic P concentrations suggesting no influence of burned materials on P sorption. Further, the presence of biochar was associated with a reduction in recalcitrant P concentrations. The lack of biochar-induced enhancement in P sorption may be due to the specific characteristics of the biochars produced from the burns and used in the experimental plots. Biomass, grass species, and pH were found to most strongly influence P distribution in the sampled marshes. The data show greater P content in Phragmites soils compared to native grass soils, suggesting that burning Phragmites and replacing it with native grasses may reduce P retention in marshes. The results of this study will add to the understanding of how prescribed burns and biochar impact P composition and cycling in salt marsh environments. Future work should explore the ubiquity of this finding and whether biochars of differing characteristics (feedstock, production conditions, mixing ratios) may provide a P storage ecosystem service.
Mechanism of BMP2 induced differentiation of bone marrow mesenchymal stem cells into adipocytes
(University of Delaware, 2024) Chukwuocha, Kelechi B.
Bone morphogenetic protein 2 (BMP2) is a crucial regulator of stem cell differentiation, influencing the fate of bone marrow-derived stem cells (BMSCs). While BMP2 is traditionally known for promoting osteogenesis, emerging evidence suggests its significant role in adipogenesis, leading to the accumulation of fat cells within the bone marrow. Mesenchymal stem cell differentiation into adipocytes relies on Peroxisome Proliferator-Activated Receptor Gamma (PPARγ) activation. The level of adipocyte differentiation within the bone marrow affects osteoblast differentiation, as both cell types are derived from the same mesenchymal lineage. Osteoblasts are responsible for bone formation, and a reduced number of osteoblasts leads to decreased bone mass and conditions such as osteoporosis. Osteoporotic patients typically exhibit a high level of BMP2, accompanied by increased adipocytes and decreased osteoblasts in their bone marrow. ☐ BMP2, due to its osteo-inductive ability, has been explored as a therapeutic agent for osteoporosis. However, the dual role of BMP2 in promoting the differentiation of MSCs into both osteoblasts and adipocytes poses significant challenges to its efficacy as a treatment for osteoporosis. BMP2 signaling is a complex process that occurs through BMP Receptor Type Ia (BMPRIa) and BMP Receptor Type II (BMPRII). High BMP2 levels at 200 nM result in BMPRIa cleavage, but the downstream effects and factors determining whether osteogenesis or adipogenesis will occur remain unclear. This study investigates the mechanisms underlying BMP2-induced differentiation of BMSCs into adipocytes, focusing on BMP2-induced BMPRIa cleavage and its impact on PPARγ expression. ☐ Immortalized murine myoblasts (C2C12 cells) and primary BMSCs from mice of different ages were treated with varying BMP2 concentrations. High BMP2 levels (200 nM) significantly increased PPARγ expression and led to nuclear accumulation of BMPRIa, as observed via immunofluorescence staining. Western blot analyses confirmed BMPRIa cleavage and identified a cleavage fragment with a molecular weight corresponding to a Caspase1 cleavage fragment in cells treated with 200 nM BMP2. In primary BMSCs, Caspase1 inhibition abolished this cleavage band, highlighting Caspase1's involvement. Furthermore, Caspase1 inhibition also prevented BMPRIa's nuclear accumulation and reduced PPARγ expression, confirming Caspase1's role in BMPRIa cleavage. In contrast, BMSCs from 15-month-old mice showed no significant nuclear accumulation of BMPRIa or changes in PPARγ expression across BMP2 treatments, indicating age-related impairment in BMP2 signaling and receptor processing. ☐ This study reveals that Caspase1-mediated BMPRIa cleavage drives adipogenesis in primary bone marrow stromal cells through nuclear interactions. Understanding these molecular mechanisms enhances comprehension of adipogenesis within the bone marrow and offers potential therapeutic avenues for modulating treatment with BMP2 in low bone mineral density and osteoporosis.
Examining the impact of source of income protection on the Housing Choice Voucher program
(University of Delaware, 2024) Bothum, Peter
We are nearly 100 years removed from the federal government’s decision to draw red lines on maps to segregate people by race and more than 50 years since the 1968 Fair Housing Act attempted to undo the damage. Yet several forms of housing discrimination continue today (Rothstein, 2017). One such practice is source of income discrimination, in which landlords refuse to rent to potential tenants because of their lawful source of income. The most common source of income rejected by landlords are Housing Choice Vouchers distributed by the U.S. Department of Housing and Urban Development (Tighe, Hatch & Meade, 2017). Presently, 33 states do not have statewide source of income laws that protect Housing Choice Vouchers;17 states and the District of Columbia have statewide or district-wide laws that do (both numbers current as of May 2023). This research will explore the extent to which these laws impact the Housing Choice Voucher program by examining key data provided by HUD between the years 2015 and 2023: which states are making the most of their Housing Choice Voucher budget; which states are leasing the most units; which states are seeing more people entering and exiting the program; which states are using the most vouchers; and which states have the shortest average wait time for vouchers. If analysis of the data shows that a relationship exists between the presence of laws and the performance of the program, the results could inform policy at both the state and local level. A strong case could also be made for further legislation, perhaps at a national level, that outlaws this tool of housing discrimination.
Evaluating wave glider meteorological and oceanographic data using in situ, modeled and remotely sensed coastal data in the Delaware region
(University of Delaware, 2024) Olamiriki, Emmanuel
One of the limitations in coastal forecasting is the lack of high spatial-resolution meteorological and oceanographic observations. The wave glider is a coastal autonomous vehicle that can obtain meteorological and coastal data in real time. The wave glider took a maiden voyage in coastal Delaware waters for 15 days in November. During this period in late fall, there were several storms and turbulent ocean conditions. In this study, we compared the wave glider atmospheric and oceanographic observations to other local in situ observations. The meteorological variables used for comparison in this study were air temperature, sea surface temperature, pressure, wind speed, wave height and wind direction. Weather radar data from the station at Dover, DE, and the Daily 1km resolution MUR SST product, were also retrieved to study the spatial variation in precipitation patterns and sea surface temperatures. Data from the Wave Glider and Buoy 44009 was used to evaluate the performance of a high-resolution, mesoscale atmospheric model (WRF).
Thermally enhanced MUTC photodiodes
(University of Delaware, 2024) Fox, Alexander T.
Modified uni-traveling carrier photodiodes offer world leading capabilities in terms of their power handling and linearity. For this reason, it is no surprise that they are an irreplaceable tool in RF Photonics, namely in RF Photonic links. As these devices develop further, applications for them will continue to grow, but not until significant advancements are made in their power handling capability. As of now, joule heating remains a factor not addressed within MUTC epitaxies which leads to thermal failure. ☐ In this work, developments are made on a new MUTC epitaxy which specifically addresses joule heating for the first time. Based on simulations from UVA, this epitaxy has the capability to increase dissipated power at failure, but to produce useful, functional devices from this epitaxy is an entirely new challenge. The process and considerations of making devices from this new epitaxy will be shown. As will be demonstrated, this epitaxy under the right conditions offers a promising future for increasing power handling capabilities.
Investigating the role of egg-3 by characterizing the egg-3(as40) phenotype in C. elegans
(University of Delaware, 2024) Hoque, Ashna Ambrin
Egg activation is a process whereby a mature oocyte transitions from meiosis to mitosis and changes to a new cellular state that supports embryogenesis. In C. elegans, egg activation is regulated by a complex of proteins which include EGG-3, EGG-4, EGG-5, CHS-1 and MBK-2. EGG-3 is a member of the protein tyrosine phosphatase like (PTPL) family that has been proposed to act as a scaffolding molecule to regulate the activity and localization of the above-mentioned proteins. ☐ My research goal is to characterize the temperature-sensitive mutant egg-3(as40) to further elucidate the role of EGG-3 in the oocyte-to embryo transition. The progeny of egg-3(as40) hermaphrodites showed signs of a developmental delay, and I investigated the possibility that this phenotype was caused by egg-3 expression occurring later in development. There was no discernible variation in the developmental rates of the heterozygous and homozygous progeny when compared suggesting that the developmental delay is due to maternally provided EGG-3 and not expression of egg-3 in later stages of embryonic or larval development. RT-PCR results also validated the germline-restricted expression of egg-3. Moreover, an eggshell permeability assay was performed which showed that the eggshell of egg-3(as40) was permeable to the lipophilic dye, FM4-64, at the restrictive temperature suggesting that there is a defect in the formation of the eggshell layer of the mutant. Calcofluor White staining also showed that the chitin layer fails to form in the mutants at 25°C. I have conducted two rounds of suppressor screens and isolated a total of six potential suppressors of egg-3(as40). While egg-3(as40) mutants produce an average of less than 1 progeny at 25°C, the suppressor lines produce an average of 5-24 progeny. I have also performed genetic analysis to determine the dominant or recessive nature of these suppressors and found that all six suppressors are dominant. In the future, we plan to use whole genome sequencing to map these suppressors to their genetic loci.
Calibration of highway safety manual prediction models for Delaware intersections
(University of Delaware, 2024) Gomes de Oliveira, Rodolfo
There has been growing momentum across the United States to develop systematic procedures for quantifying and predicting safety in order to build up safer roadways for all users. Over the last century, highway safety-related decisions at the project level were mostly made based on engineering judgment experience and standards compliance. Published in 2010, the Highway Safety Manual (HSM) provides information and methodologies on measuring, estimating, and evaluating roadways in terms of safety. The HSM introduces techniques for predicting crashes based on predictive models developed by different researchers in different periods and from different regions using base conditions. The main goal of this research is to calculate calibration factors to account for the difference between predictive methods under base conditions and under Delaware-specific conditions. This analysis was performed collecting data mostly from the state of Delaware, Google Street View, and satellite imagery. The research utilized the software ArcGIS Pro to store data and perform spatial analysis. Calibration factors and their goodness-of-fit measures are calculated for all HSM intersection classifications (ten site types). This research also provides local crash distribution proportion tables based on injury severity level and collision type. The results suggest that calibration factors for five site types are recommended for use, and five site types are not recommended for use. In general, calibration factors were higher than 1.0, implying that the HSM predictive models underpredict reported crashes in Delaware. The study concludes with a discussion on data limitations, thoughts about HSM crash prediction methodology, and suggestions for future research.

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