Undergraduate Senior Theses

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A senior thesis is a paper which highly-motivated senior undergraduates may write to present the results of a major, independent research or creative project. Unlike most term projects, papers, and lab reports written in undergraduate courses, a senior thesis addresses questions or issues for which no known or generally accepted answers exist.

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The Association Between Depression & Marriage Quality Using the CES-D & RMICS2
(University of Delaware, 2023-05) Sara Wichtendahl
Individuals that experience depressive symptoms are at higher risk for poor marital quality and distress. Some theories suggest that for depressed individuals, stress generated from negative life events can perpetuate their depression further, causing the individual to need more support from their partner. If this need is not met, the depressed individual may feel rejected and lose their sense of belonging with their partner. Both this and stress can induce depressive-like symptoms that form through biological processes. The present study looks to investigate the relationship between depression and marital quality under the conditions of marital conflict discussions. Both partners of a couple (N= 72) were asked to complete various questionnaires and a conflict discussion task. Marital Quality is assessed via the conflict discussion tasks that are coded using the Rapid Marital Interaction Coding System- Version 2 (RMICS2). Observational codes from the discussion task were summed to find marital quality for each partner. Depression was measured using a self-report questionnaire, the Center for Epidemiological Studies Depression (CES-D) scale. It was found that individuals that exhibit higher levels of depression are more likely to exhibit lower levels of marital quality than individuals with lower levels of depression. The relationship between depression and marital quality’s implications on physical and mental health, COVID-19, and therapeutic approaches are discussed.
Development of Click Nucleic Acids for Biosensing
(University of Delaware, 2019-05) Bischoff, Derek
Herein, a new type of nucleic acid analog referred to as a ‘click nucleic acid’ (CNA) is described. Nucleic acids, such as deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), as well as current analogs, such as peptide nucleic acid (PNA) and locked nucleic acid (LNA), have been used in many lab scale applications that leverage the complementarianism between two sequence specific strands of the polymer. Limitations of the current methods not only prevent widespread use in vivo due to enzymatic degradation and hydrolysis, but also are quite costly to scale up and utilize inefficient reactions to make these periodic polymers. The proposed CNA material that can overcome these issues is built using the same four nucleobases that are found in naturally occurring DNA with the naturally occurring phosphate-sugar backbone replaced with a neutral, primarily alkane backbone that could lead to tighter binding of complementary strands. The ‘click’ portion of its name refers to click chemistry, a subset of chemical reactions that are highly efficient and proceed under ambient conditions. This CNA material has the benefits of reusing excess monomer, efficient click chemistry, scale up, and cleaner purification. The synthesis of the four nucleotide mimicking monomers follows a four or five step synthetic pathway involving commonly employed organic reactions such as an alkylation, hydrolysis, reductive amination, and substitution/elimination. Subsequently, a solid phase synthesis protocol is outlined to provide sequence specific polymers using a protecting group strategy similar to typical Fmoc peptide synthesis. Initial results show that solubility is an issue that is preventing polymers larger than three units long from being both synthesized and characterized. In overcoming this challenge, a variation on the four nucleobase mimicking monomers has begun development that adds an extra carboxylic acid functionality to the backbone that should help with solubility.
A Therapeutic Evaluation of a Creative Reaching Game in Immersive Virtual Reality
(University of Delaware, 2022-12) Baron, Lauren
Virtual Reality (VR) has several applications beyond entertainment, e.g., architectural planning, surgical procedure assistance, and physical therapy. These implications are important and require the most accuracy for users, especially when their healthcare is involved. Users can lose accuracy immersed in a virtual environment (VE) from inaccurate depth perception. Often, people underestimate distant objects and overestimate close objects in VR, which concerns software developers and healthcare providers. VR Therapy systems also rely on information from VR hand controllers, which do not fully capture the movement from the rest of the limb. While VR games have shown much potential for rehabilitation, research on creative virtual therapy is still growing. Considering many possibilities for therapeutic interventions in VR, my goal is to create activities with an appropriate balance between the intensity level of therapy intervention with enjoyment and entertainment. I will also capture the limb's movement both from the arm and hands with a noninvasive elbow sleeve sensor. I propose a creative line art drawing game in an immersive VR environment as a tool for both upper extremity therapy and vision therapy using enjoyable multi-dimensional reaching tasks. To examine the validity of the proposed virtual therapy system, I conducted two preliminary human-subjects experiments: a mixed design varying the drawing content (Easy vs. Hard; a between-subjects factor) and the user’s position (Seated vs. Standing; a within-subjects factor) on 16 non-clinical participants; and a withinsubjects design varying the drawing content dimension (2D vs. 3D) and the content’s orientation (Vertical vs. Horizontal) on 12 non-clinical participants. My results of the first experiment (SUI 2021) show that the change of drawing content objectively influenced participants’ drawing performance, e.g., the completion time and the number of mistakes, while they did not feel the difference in the difficulty level between the contents subjectively. Interestingly, participants reported more enjoyment from drawing the Hard Chicken content than the Easy Fish content and more substantial body stretches in the Seated setting than the Standing setting. The results of the second experiment (submitted to ACM/IEEE CHASE 2023) show that for all levels, there was no significant difference between subjective easiness, comfortability, and enjoyment and between objective measures for task completion time and the number of mistakes. This finding suggests that all versions are at the same therapeutic intensity level, with no model being more prone to longer time or more mistakes and are all usable/feasible. This leads to the customization of therapy to the user with any of these configurations and orientations while keeping the same level of intensity; for example, if a patient has restricted lower limb mobility and requires to be seated, they can use the horizontal orientation interchangeably. However, there was significance with elbow resistance change, which shows how data collection from just the hands and not throughout the arm is insufficient for VR rehabilitation, particularly for the upper extremities. There is a need to improve depth perception, visual cues, and reaching capabilities in VEs, especially for 3D objects.
Characterization of molecular and metabolic phenotypes of Clostridium syntrophic co-culture
(University of Delaware, 2022-05) Zou, Yin
Historically, Clostridium species were used in Acetone-Butanol-Ethanol (ABE) fermentation. However, the ABE fermentation processes face competition from petroleum based processes, thus fermentation processes need to evolve to produce a higher valued chemical efficiently. Clostridium species are known to metabolize a range of sugar molecules and produce valuable chemicals such as hexanol and octanol. To achieve this goal, utilization of co-culture allows each species of bacteria to specialize in one task and avoids complex metabolism engineering. In this thesis, optimization of the bioreactor performance of syntrophic Clostridium co-culture for medium chain alcohol or fatty acid production utilizing Clostridium kluvyeri and Clostridium saccharolyticum. And the characterization of the molecular interactions and localization of proteins of interest related to cell-to-cell interaction was investigated. In the bioreactor investigation, the optimized C. kluyveri monoculture yielded 173 mM of hexanoate. In comparison the co-culture yielded 123 mM of hexanote. The result exhibits promising industrial value for Clostridium co-culture, and the insufficient supply of ethanol from C. saccharolyticum could be the major drawback for this co-culture system, which may be improved by incorporating a third species into the system such as Clostridium ljungdahlii. Direct cell-to-cell material exchange between Clostridium acetobutylicum and C. ljungdahlii has been previously shown by our lab 1 This phenomenon greatly improves the productivity and carbon utilization in the co-culture, thus understanding the mechanism of cell-to-cell material exchange is critical to improve the performance of the co-culture and bring more industrial and economical significance. It is possible that C. ljundahlii could be actively seeking CO2 rich source and therefore fused with C. acetobutylicum to consume CO2 waste produced by C. acetobutylicum. To further investigate this phenomenon, the localization pattern of the proteins of interest such as carbonic anhydrase (CA) and methyl-accepting chemotaxis protein (MCP) could be helpful. These proteins may be involved in CO2 metabolism and CO2 sensing respectively. To visualize the localization of these proteins, Halotag was fused with the two proteins of interest. The preliminary testing of the fluorescence of both MCP Halotag and CA-Halotag under the microscope in Escherichia coli and under the flow cytometry in C. ljungdahlii shows the strong fluorescent intensity of the fluorescent fused protein. Visualizing the proteins in C. ljungdahlii under the microscopy, uniform membrane localization of MCP-Halotag and uniform cytoplasmic localization were observed. Future experiment of fluorescent imaging C. acetobutylicum and C. ljungdahlii utilizing the MCP-Halotag and CA-Halotag could provide more information about the proteins involved in the cell-to-cell direct material exchange.
The Effect of Nicotinamide Riboside on LDL-Cholesterol Induced T-Cell Dysfunction
(University of Delaware, 2022-05) Ward, Houston
Aging is associated with chronic low-grade inflammation (“inflammaging”) and is a significant risk factor for multiple chronic diseases, including cardiovascular disease, Alzheimer’s disease, and cancer. Inflammaging is caused by the deterioration of the innate and adaptive immune systems, often accompanied by immunosenescence. T-lymphocytes (T-cells), primarily known for their role in the adaptive immune system responding to foreign antigens, are increasingly recognized as contributors to inflammaging via immunosenescence and impaired mitochondrial function. Age-related declines of cellular nicotinamide adenine dinucleotide (NAD+) levels may be the trigger of immunosenescence and mitochondrial dysfunction. However, the mechanisms leading to T-cell mediated inflammaging and mitochondrial dysfunction are not fully known. One mechanism which might contribute to age related T-cell dysfunction is an increase in endogenous low-density lipoprotein cholesterol (LDL-C) in blood plasma. Increased endogenous LDL-C occurs with aging and has been linked, cross-sectionally, to mitochondrial damage and dysfunction, reduction of ATP synthesis, and increased reactive oxygen species. Subsequently, this damage can lead to various cellular consequences, rapid aging, and disease onset. Supplementation with nicotinamide riboside (NR), a precursor to nicotinamide adenine dinucleotide (NAD+), might be a novel therapeutic to protect T-cells from the deleterious effects of high LDL-C. In addition to its role as a regulator of cellular reoxidation-reduction reactions, NAD+ is a critical co-substrate for several energy-sensing and stress-resistance enzymes. These enzymes are referred to as “NAD+- consuming enzymes” and include the silent mating type information regulation of two homologs (sirtuins; SIRTs), poly adenosine diphosphate (ADP) ribose polymerases (PARPs), cyclic ADP (cADP)-ribose synthases, and CD38/156 ectoenzymes. These enzymes contribute to a multitude of homeostatic processes including the maintenance of biological stress resistance, DNA damage repair, and the regulation of immune cell function. Supplementation with NR has been shown to increase NAD+ bioavailability. NAD+ has emerged as a vital and intriguing cofactor for maintaining mitochondrial fitness by up-regulating enzymes that repair mitochondrial DNA. However, whether NAD+ can protect T-cell mitochondria from immunosenescence is unknown. This study aimed to investigate the efficacy of exogenous NAD+ supplementation in protecting young T-cells from the effects of hypercholesterolemic conditions associated with aging. I hypothesized that treatment with LDL-C would impair T-cell mitochondrial respiration and induce T-cell inflammation and that NR would exert a protective effect on T-cells, preserving mitochondrial respiration and reducing the inflammatory response. Seven adults (6 female/ 1 male) between the ages of 22 and 26 participated in this study. Blood samples were collected in EDTA coated vacutainer tubes from all 7 participants. Peripheral Blood Mononuclear Cells (PBMCs), isolated from whole blood, were further isolated into a pan T-cell sample. The isolated T-cells were later treated and used for the Seahorse XF Analyzer. The supernatant was isolated and frozen to use for the quantification of cytokines. Pan T-cells were treated with high (4.9 mMol/L) physiologic concentrations of LDL-C and co-incubated with high LDL C and NR compared to control (Serum-free media, 0 mMol/L). T-cell mitochondrial function and inflammatory cytokine production were assessed by measuring mitochondrial respiration using an extracellular flux analyzer (Seahorse XFe96 Analyzer) and multi-plex protein quantification (Luminex Magpix), respectively. Concentrations of pro-and anti-inflammatory cytokines, specifically interleukin-6 (IL 6) and interleukin-10 (IL-10), were measured across the three treatment groups of the pan T-cell samples. Proinflammatory cytokines up-regulate the production of radical oxygen species (ROS) and anti-inflammatory cytokines reduce the production of ROS. Contrary to our hypothesis, LDL-C non-significantly augmented T-cell mitochondrial respiration during maximal oxygen consumption rate (OCR), while it non-significantly decreased basal OCR and ATP-linked OCR. Further, the addition of NR to LDL-C treated samples exacerbated mitochondrial respiration in all accounts. Anti-inflammatory cytokine production showed a non-significant decrease with the LDL-C and LDL-C+NR treatments. Proinflammatory cytokine production displayed a non-significant increase within the LDL-C and LDL-C+NR treatment groups. The additional NR treatment to LDL-C treated T-cells significantly decreased the basal, maximum, and ATP-linked OCR, but it is unclear if LDL-C treatment alone had a significant effect on T-cell mitochondrial dysfunction. Cytokine production was not significantly affected with either treatment at the current sample size and may require more samples to clarify a relationship.
Impact of the GTP Binding Protein ARF-6 on the Biogenesis of Multiple Extracellular Vesicle Subpopulations in C. Elegans
(University of Delaware, 2022-05) Wagner, Katherine
Extracellular vesicles (EVs) are nano-sized, membrane-bound vesicles that play crucial roles in intercellular communication, impacting both physiologic and pathophysiologic pathways. Use of the genetic model organism C. elegans allows us to study and track EVs and their cargoes in vivo, to observe EV biogenesis and shedding. C. elegans EVs contain various different cargoes, including the calcium homeostasis modulator CLHM-1 and the polycystin PKD-2 ion channels. These cargoes are found to be in two different EV subpopulations that bud from different locations on the cilia of male tail sensory neurons. The small GTPase ARF-6 has been suggested to participate in microvesicle shedding via the phospholipase D pathway of signal transduction based on in vitro studies. However, whether ARF-6 plays this role in the release of EVs from cilia in vivo is unknown. Here, we show, using fluorescent protein tagging and TIRF microscopy, that ARF-6 affects both CLHM-1 and PKD-2-containing EVs, indicating that this protein may act in male-tail sensory neurons to impact biogenesis of all EV subpopulations. Loss of ARF-6 results in an approximate 50% reduction in release of both EV populations, opening the door for several future hypotheses and lines experimentation using the arf-6 mutant.
Illness as Metaphor: Comparing the Transatlantic Representations of Neurological Deviance in the Works of Charles Dickens and Herman Melville
(University of Delaware, 2022-05) Sarikonda, Advith
Charles Dickens’ Barnaby Rudge: A Tale of the Riots of Eighty (1841) and Herman Melville’s “Bartleby, the Scrivener: A Story of Wall Street” (1853) are two stories featuring titular protagonists whose neurological conditions mark them as different from the rest of society. The eponymous protagonist in Barnaby suffers from “idiocy,” now formally termed intellectual disability disorder, whereas the eponymous protagonist in “Bartleby” displays traits of autism, a condition characterized by an impairment in language and communicability. Although Dickens and Melville both present characters who are neurologically deviant, the purpose of doing so is diametrically different in each work. Through Barnaby, Dickens expresses a need for paternalistic reform on both a state and communal level to assist the mentally ill, as well as the rest of society’s most vulnerable groups. Barnaby is not an unambiguous censure of British society, however; in the story, Dickens suggests a need for the existing British practice of moral management, which was a technique of non-restraint originally used in state asylums to treat the mentally ill. Melville, on the other hand, uses “Bartleby” to criticize the American medical system’s tendency to institutionalize members of society who are considered to be “deviant”. In the case of “Bartleby”, this deviance is communicated through autism, which manifests itself into seemingly unusual patterns of work and correspondence that confuse the story’s narrator, a lawyer. As such, “Bartleby” and Barnaby represent ideologically opposing perspectives of medicine and its potential to heal society’s outcasts. Whereas Dickens expresses interest in assisting individuals deemed to be non-normative, Melville portrays normativity itself as mercurial and conditional rather than an innate human disposition.
Genomic Sequencing of Single Ciliate Protozoa Cells from Equine Fecal Material
(University of Delaware, 2022-05) Vega, David
The equine hindgut is home to a myriad of microbes including bacteria, archaea, fungi, and protozoa that allow for digestion and usage of a forage-based diet. This study sought to expand the current 18S database for equine gut protozoans by optimizing a ciliate-specific PCR protocol. Fresh equine fecal samples were collected and combined with 1X PBS to create a slurry solution. This slurry underwent filtration steps which included a series of five filters of decreasing size (200µm, 100µm, 70µm, 40µm, 10µm). Samples were observed under an inverted microscope and protozoans were manually single sorted. Cells were washed from debris and stored at -80°C in a 1-µL droplet in a PCR tube. DNA extraction optimization included two different series of freeze/thaw steps and a Chelex 100 mechanical disruption protocol. PCR amplification was optimized using ThermoFisher Scientific Phusion™ High-Fidelity DNA Polymerase and P-SSU54F or 82F and P-SSU1747R or EkyB primers (Ito et al., 2014, Sylvester et al., 2004). Custom designed inner primers, VegaF0721 and VegaR0821, were used in a nested primer approach for Sanger sequencing. Data from previously unsequenced species Blepharoconus benbrooki and Blepharocorys valvata, were obtained, as well as sequences from already sequenced species Cochliatoxum periachtum, and Tripalmaria dogieli. It was observed that the forward reads for each sequence were of high quality, and thus the forward primer proved to be more successful. It is recognized that the reverse primer produced poor reads and these sequences were not used within the study and the VegaR0821 inner primer needs to be re-evaluated for effectiveness. A small equine dataset (n=45) was obtained from the Equine Microbiome Project (Berg et al., 2017) to determine the prevalence of the five species obtained from single sorting experiments in equine fecal samples. Results showed that the five single-sorted species were highly prevalent within the samples, validating the approach and need for an expansion of the 18S database. Neighbor Joining trees revealed that the putative P46-Blepharoconus benbrooki and P42- Blepharocorys valvata samples did not cluster close to other species in their genus. It is to be noted that the Blepharocorythidae family has the possibility of being polyphyletic (Cedrola et al., 2021) and thus may account for the differences seen within the Blepharocorys valvata samples.
Comparison Between the TSA2 and the Medoc Pathway in Assessing Thermal Leg Sensitivity
(University of Delaware, 2022-05) Tulsky, Gwyneth
Quantitative Sensory Testing (QST) is a method used to quantify somatosensory function in large and small nerve fibers to detect sensory loss (i.e., hypoesthesia, hypoalgesia) or sensory gain (i.e., hyperesthesia, hyperalgesia, allodynia) that may be associated with acute and chronic pain. A set of objective testing procedures that include both thermal and mechanical test stimuli are administered based on a protocol. Thermal stimuli are administered with the gold standard Medoc Pathway, a stationary and heavy piece of equipment, however, a new to the market portable Advanced Thermosensory Stimulator (TSA2) is now available for testing with many of the same functions as the pathway; however, it has not been tested in the lower extremity. The aim of this study is to evaluate the agreement in thermal testing between the two machines. This is a repeated-measures two group study with two test sessions one day apart (N=20). Thermal testing consisted of warm/cold detection and heat/cold pain. Statistical analyses include paired t-test for mean differences, Pearson’s correlation for agreement, intraclass correlation and coefficient alpha values, and Bland-Altman’s plots for differences between the measurements. Mean age for participants was 32 years (SD=14.3) and evenly split between men and women. The paired t-test revealed no significant differences between the TSA2 and Medoc Pathway. Pearson correlations show strong correlations for thermal pain on the TSA2 and Medoc Pathway. High alpha values were revealed on all tests conducted, except for warm detection. Bland-Altman plots reveal agreeable data for cold detection, cold pain, and warm pain. Warm detection displayed a distinct pattern where there were differences between the Medoc Pathway and TSA2 when temperature rose, which might account for the low alpha value for warm detection.
The Implementation of Trauma-Informed Practices In Music Education
(University of Delaware, 2022-05) Taylor, Pauline
Trauma and traumatic experiences have been shown to impact the brain and brain functioning, which in turn can severely impede a student’s ability to learn and function in a classroom (Perry, 2016). Over the past few decades, trauma-informed practices have been developed to help mitigate the negative effects of trauma. Trauma informed practices are research and evidence-based strategies that educators and other professionals use to help support students with trauma. Additionally, music is frequently used as a modality for the treatment and healing of trauma in the field of music therapy due to the positive impacts that music has on the brain. Despite the significant amount of research that focuses on these benefits, there is currently very little literature on trauma-informed practices in music education. This thesis aims to fill this gap in the research literature by reviewing current literature in the fields of music therapy, neuroscience, psychology, and education. For this senior thesis, I also interviewed three music educators currently implementing trauma informed practices in their music classrooms. I identified key practices educators are using in their classroom, how they discovered these practices, and what educators thought were their barriers to implementation based on the interviews and the literature review.
Body Composition and Behavior: Metabolic Implications of Birth via Cesarean Section in Prairie Vole (Microtus ochrogaster)
(University of Delaware, 2022-05) Starr, Alexandra
Throughout the United States the rates of performed cesarean section (CS) have increased. The scientific community has observed an association between birth by cesarean and the offspring's increased weight at maturity (Masukume, 2019). Studies are being conducted to better understand the relationship between cesarean delivery and offspring metabolism (Kozhimannil, 2013; Kenkel, 2020). To test this potential connection, a diet intervention study has been used to test vaginal delivery (VD) vs CS birth subject’s weight gain using a prairie vole model. Vole diets were either supplemented with a high-fat alternative mixed chow (MC) or fed standard vole chow (VC) to induce weight gain. Through this study, we collected sucrose preference, home cage, food consumption data from both birth mode groups and diet conditions. At sacrifice, we collected measures of weight, length, and adipose tissue to analyze for post mortem body composition in adulthood of each group. CS voles gained more weight than VD voles, despite having lower food consumption and greater locomotive activity. Body composition analysis found that CS animals were longer and heavier than their VD counterparts. Additionally, CS animals were found to have a larger percent brown adipose tissue relative to body weight compared to VD counterparts. Future studies will target the variables contributing to this weight gain among CS offspring by examining factors like muscle mass, and total adiposity through advanced imaging data. Future studies will incorporate exogenous oxytocin administration to examine the impact of birth mode on body weight, metabolism, adiposity, and later life development to determine the possible mechanisms impacting the metabolic outcomes seen in this study.
Mainstream American News Media: Is It as Polarized as Its Consumers Over the Issues of Climate Change, COVID, and Immigration? A Cross-Country Study of U.S. and U.K. News Media
(University of Delaware, 2022-05) Spruill, Rachel
Does U.S. news media really just cater to the existing partisan divide? Studies show that American society has grown more polarized on a partisan basis, yet in the United Kingdom, party loyalty is splintering and growing weak. If news media is truly just a business, we can expect U.S. news coverage to be more ideologically polarized than that of the U.K. The role of the media as a political influence has been the subject of much scholarship, but there lacks a database in which multiple content-related variables can be compared across countries. The objective of this study is to compare the media landscapes of the U.S. and the U.K. over shared political issues: climate change, COVID vaccines, and immigration. To do so, a collection of 600 articles across multiple news outlets in both the United States and the United Kingdom were quantified based on ideological leaning, key source, and article type. It was found that U.S. news articles are only slightly more likely to be ideological, and after controlling for the greater number of opinion articles in the U.S., there is no difference in the levels of ideology between the two countries’ media. This means that 1) the ideology of U.S. news coverage is not as dramatic as a business model would expect, and 2) if the U.S. news media is more ideological than that of the U.K., it is due to a greater number of opinion articles rather than innate outlet bias
Identity, Spirituality, And Community At The John Dickinson Plantation Based On The Collection From Block III
(University of Delaware, 2022-05) Side, Samantha
This thesis analyzes material culture from the most recent excavation completed in 2000 at the John Dickinson Plantation. This thesis aims to better understand how the enslaved population who lived and worked in this area interacted with and used this material culture to persist, resist, and survive bondage. Specific artifacts such as an amethyst, varying dress items, ceramics, and a rumbler bell that were found in features such as barrel pits, a packed earth floor, a post hole, and a possible hearth were the focus of this analysis in order to consider what artifacts relating to identity, spirituality, and community can tell us about the experience of those who were enslaved at this site during the 1720 to 1820 time range. Through the use of comparative historical and archaeological studies, resources regarding slavery in Delaware and the Mid-Atlantic, and the use of excavation field notes, images, and summaries; it is evident that these artifacts were used to create a separate geography from the dominant white plantation geography. The artifacts from Block III reveal the complex actions and interactions that are important to understanding how the enslaved population was able to imbue not only creativity onto their surroundings but create space for the continuity of African cultural traditions within this environment of bondage.
Analysis of Type IV pilin in Vibrio parahaemolyticus
(University of Delaware, 2022-05) Shum, Chun-kit
Vibrio parahaemolyticus is a Gram-negative bacterium that is ubiquitous in the marine environment and is also a human pathogen that when ingested induces gastroenteritis. This bacterium expresses on its surface rod like hair-like appendages called pili. Pili are important for bacterial adherence to surfaces such as shellfish and human cells. The V. parahaemolyticus genome contains several different pili, but the most common class of pili is the type IV. In V. parahaemolyticus, four type IV pili have been identified, two of which are TAD Caulobacter Pilin Assembly (CPA) type IV pilins, as well as the mannose-sensitive hemagglutinin (MSHA), and the chitin regulated pilus (ChiRP/Pil). MSHA pilin is required for adherence, biofilm production, and twitching motility. CHiRP is required for adherence to chitin surfaces and natural transformation for DNA uptake. This study focused on the characterization of one of the two TAD CPA type IV pilins, the TAD1 CPA type IV pilin. In this work, a non-functional TAD1 mutant strain was constructed by deleting the pilin protein encoded by the VP2423 gene creating a ∆VP2423 mutant. The mutant strain was then characterized using growth pattern analysis and phenotypic assays: swimming and swarming assays, capsule polysaccharide production, and biofilm formation. The mutant strain grew similar to wild type in all these assays.
“Can’t Tote No Gun but I’m Strapped Right Now”: Hip-Hop as Language and Refuge Amongst Low-Income Black Youth
(University of Delaware, 2022-05) Sherba, Gabrielle
This project seeks to (1) highlight the importance of hip-hop/rap music in the lives of low-income Black youth, (2) trace low-income Black youths’ internal processing of hip-hop/rap music and (3) demonstrate the communicative potential of hip-hop/rap in understanding the lived experiences of low-income Black youth. To gain insight on low-income Black youths’ interaction with hip-hop, a select group of low-income Black youth from the Riverside neighborhood in Wilmington, DE participated in an online survey and semi-structured follow-up call pertaining to their hip-hop/rap listening. The youths’ responses indicate that hip-hop is a vehicle for youth to (1) identify and process their lived experiences and (2) engage in healthy emotional regulation. In addition, lyrical hip-hop translations provided by youth, alongside contemporary sociolinguistic framings of hip-hop language, reveal phenomenological complexities in low-income Black youth’s lived experiences that are otherwise ineffable. Centrally, the study connects the role of hip-hop among low-income Black youth to its linguistic potential and offers hip-hop as a valuable tool for youth-centered researchers and educators.
Factors Affecting Overwintering Success Of Spathius Galinae, A Parasitoid Of The Invasive Emerald Ash Borer (Agrilus Planipennis)
(University of Delaware, 2022-05) Scherr, Adam
Spathius galinae Belokobylskij is one of a few parasitoid wasps used as a biocontrol agent against the invasive emerald ash borer (Agrilus planipennis Fairmaire), a destructive beetle that has killed tens of millions of ash trees in the U.S. S. galinae are known to overwinter as prepupae in silken cocoons, but little is known about the overwintering success of these parasitoids at earlier life stages. Logs containing three different life stage treatments of S. galinae (early instar larva, mid instar larva, and prepupa) were placed in jars and deployed in two different microhabitat sites (urban woods and mature woods). The logs were deployed in late fall, remained in the field through winter, then S. galinae emergence was recorded in spring. Parasitoids in the warmer urban site emerged an average of 14 days earlier than parasitoids in the cooler, shaded mature woods site. S. galinae from all three life stage treatments successfully emerged, although the exact effect of life stage on overwintering success is not completely clear. Researchers in the future can release S. galinae for biocontrol through mid and late fall, but another study should be conducted to determine if young larval S. galinae have any less overwintering success than prepupae.
Exploration of the Object-Based Warping Illusion: Distortions of Space Due to Objects and Grouping
(University of Delaware, 2022-05) Scanlon, Catherine
Our perception of visual objects is amongst the most important aspects of our visual perception. While most illusions of space focus on depth or comparison cues, another class of object-based illusions elicit effects from their own innate properties. Whether or not these warping properties of illusions exist uniformly or separately between singular objects and strongly grouped objects is a topic of debate in visual perception literature. We further explore the object-based warping (OBW) illusion and the one-is-more (OIM) illusion in a set of two studies: the first of which studies the effects found in the OBW illusion on a continuum of objecthood, the second of which studies the combination of effects between the OBW and OIM illusions. The first study showed that grouped objects exhibit object warping effects, and these effects exist on a continuum directly correlated to objecthood strength. The second study showed that expansion effects increase uniformly with increasing objecthood, from two objects to one object. However, the second study provided contradicting results as well, where the compression effect increased uniformly from one object to two objects. This provides evidence for the potential distinction of processing between strongly grouped objects and singular objects.
Separation Of NMC And Carbon Nanoparticles Via Sedimentation For Lithium-Ion Battery Direct Recyclin
(University of Delaware, 2022-05) Ross, Stephanie
Lithium-ion batteries are used in a variety of electronics today and are expected to increase in usage with the rise in electric vehicles. However, the recycling processes of these batteries must be improved to reduce or eliminate the environmental harm created by them. This thesis features the separation of cathode active material in water through the use of a sedimentation pool. The settling behavior of NMC and carbon nanoparticles is characterized by a set of graduated cylinder experiments, where it was found that carbon nanoparticles will typically float in water if they do not form large agglomerates. Observations from this set of trials align with the principles of Stokes’ Law and the interparticle collision theory. Operating parameters of the constructed sedimentation pool were determined through flow visualization and NMC displacement trials. In the NMC region of the sedimentation pool, 92 wt.% of the collected particles were determined to be NMC through the use of thermogravimetric analysis. In the carbon region of the pool, 60 wt.% of the sample collected was NMC. The large amount of NMC collected in the carbon region is suspected to be a result of the formation of carbon agglomerates which trap the metal oxide. The conclusion of the report discusses design recommendations.
Mind the Gap: Lessons from a Review of Environmental-Induced Migration Definition and Policy Proposals
(University of Delaware, 2022-05) Reece, Kristen
Despite the term “climate refugees” becoming widely used in the media to describe individuals fleeing adverse environmental events, cases such as Teitiota v. New Zealand (2021) demonstrate the term’s lack of defined legal rights. Despite this legal gap, the number of environmental-induced migrants is expected to increase. Scholars have sought to define these individuals and propose solutions to address this gap. This paper conducts a systematic literature review of papers that answers the following two questions: (1) How are ‘climate refugees’ being defined in the legal literature? and (2) What types of proposals are being discussed in legal scholarship to increase legal protections afforded to ‘climate refugees’? After collecting and analyzing the data from 60 articles, the paper provides a categorical framework to guide a content analysis of both definitions and proposals. Through a content analysis, this paper identifies three main barriers to crafting an effective response to environmental-induced migration: integrating multi-causality into selecting a definition, overcoming a lack of political will to adopt a hard-law solution and using a climate justice lens to craft a substantive proposal. By discussing these barriers, this paper also identifies useful practices that can be leveraged to address the current legal gap in face of an increasing number of environmental-induced migrants.
Understanding Undergraduate Student Experiences And Priorities For Returning To Campus During The Covid-19 Pandemic At The University Of Delaware
(University of Delaware, 2022-05) Rao, Abhigna
The COVID-19 pandemic had numerous implications for institutions of higher education regarding the development of campus regulations, the transition to virtual and hybrid working and learning modalities, and the experience of undergraduate college students. In order to understand the impact on students at the University of Delaware, the present study was undertaken: 1) to conduct a review of past literature that examined impacts of the pandemic at universities comparable in size to the University of Delaware, 2) to perform a data analysis of the qualitative responses garnered through the Student Return to Campus Survey administered by the Center for Research in Education and Social Policy (CRESP) in Spring 2020, and 3) to identify common themes of student experiences and priorities during the pandemic years to inform future recommendations for health crisis management at the University of Delaware. The study utilized secondary data analysis from an online survey of 2,941 Freshman, Sophomore, and Junior students from the 2020-2021 academic year completing the Student Return to Campus Survey. The data analysis revealed a set of common outstanding themes, which were categorized into the following: Overall Feelings About the Pandemic at UD; Quality and Accessibility of Education in a Virtual Learning Environment; Quality of Student Life; Mental Health; Thoughts and Attitudes About Vaccination Policies, Masking, Testing, and COVID Guidelines at the University; Return to Campus; Notes and Recommendations to Administration. These major topics branched into further, more specific topics that touch on particular aspects of the main categories that were expressed through the qualitative data. Findings demonstrate that students’ perspectives and experiences were influenced by a number of factors that all should be considered in future instances of crisis management.

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