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UDSpace also includes all doctoral dissertations from winter 2014 forward, and all master's theses from fall 2009 forward.

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Recent Submissions

2026, 36th Issue, part 2
(Newark, Del.: Chesapeake Pub. Corp., 2026-10-09) Newark post
2026, 36th Issue, part 1
(Newark, Del.: Chesapeake Pub. Corp., 2026-10-09) Newark post
THE ROLE OF ACTIN-STABILIZING PROTEIN, TROPOMYOSIN 3.1, IN REGULATING CHONDROCYTE HOMEOSTASIS
(University of Delaware, 2026-05) Arranguez, Mark
Cartilage is the smooth, avascular tissue found on the ends of long bones that allows frictionless joint mobility but lacks the ability to self-repair, often leading to osteoarthritis (OA) after injury. In a surgical mouse post-traumatic OA model, the actin cytoskeleton is the most affected gene set.1 Contrary to the traditional view that cortical filamentous (F-)actin cytoskeleton of chondrocytes reorganizes to form F-actin stress fibers during OA, the surgical mouse PTOA model instead observed a loss of F-actin.2 As F-actin depolymerization is associated with loss of PRG4 in chondrocytes, elevated expression of proteases in other cell types (i.e. tendon), and cell death,3,4,5 F-actin loss may be central in OA progression. Thus, understanding the regulation of F-actin in OA can be vital for preventing cartilage degeneration. We investigate a unique group of actin-binding proteins, the Tropomyosin (Tpm) family. Considered to be master regulators of actin organization, there are over 40 non-functionally redundant isoforms found in mammals.6 Currently, it remains unclear which Tpms are expressed in murine articular cartilage. Because specific Tpm isoforms determine the diverse functions of the actin cytoskeleton, defining which Tpm isoforms are expressed in mouse cartilage is a prerequisite for understanding how actin homeostasis is disrupted in OA. We have identified Tpm3.1 to be expressed by human, bovine, and murine chondrocytes. In this study, we test the hypothesis that Tpm3.1 plays a critical role in regulating chondrocyte cortical F-actin to maintain chondrocyte homeostasis. We determined that both Tpm3.1 knockout and TPM3.1 inhibition reduced cortical F-actin levels. In bovine primary chondrocytes, we found that TPM3.1 inhibition resulted in a shift toward a catabolic chondrocyte phenotype, marked by loss of chondrogenic markers and increased protease expression. Ultimately, these findings suggest that Tpm3.1 is essential for maintaining chondrocyte cortical F-actin and chondrocyte homeostasis. Targeting chondrocyte Tpm isoforms may serve as potential targets to stabilize cortical F-actin and prevent PTOA pathogenesis.
JUST-IN-TIME DIGITAL INTERVENTIONS: EVIDENCE FROM THE CONSUMER FOOD INSIGHTS SURVEY
(University of Delaware, 2026-05) Aucker, Emma
This study examines consumer perceptions of just-in-time (JIT) digital interventions designed to promote healthier food choices in online grocery environments. While prior research shows these interventions can improve purchasing behavior, less is known about how consumers evaluate them, which is critical for real-world effectiveness. Using a nationally distributed survey of 2,023 U.S. adults, the study evaluates six JIT interventions—swap recommendations, basket feedback, sorting, filtering, pre-sorting, and pre-filtering—across perceived usefulness, intrusiveness, and coerciveness. Results show generally moderate receptiveness, with interventions viewed as somewhat useful and only mildly intrusive or coercive. However, perceptions vary significantly by design. User-initiated tools, especially sorting and filtering, are rated more favorably than retailer-initiated interventions, indicating the importance of perceived autonomy. Income has a small positive association with usefulness but does not meaningfully change relative preferences. Overall, findings highlight a tradeoff between effectiveness and acceptability in digital food interventions.
Synthesis, Characterization and Magneto-Optical Activity of A3B and AB3 Porphyrins
(University of Delaware, 2026-05) Bodio, Elizabeth
Magneto-optical activity (MOA) is the change in a material’s optical response under an applied magnetic field and is a powerful tool to achieve this control through two primary effects: magnetic circular dichroism (MCD), and magneto-optical rotary dispersion (MORD). MCD is the differential absorption of left- and right-circularly polarized light, and MORD, also known as Faraday rotation, is the rotation of planepolarized light as it propagates through a magnetized medium. These magneto-optical properties support technologies such as optical isolators in lasers, which protect instruments by rotating light to block back-propagating beams and can potentially be used as sensitive detection devices that measure extremely weak magnetic fields generated in the brain and heart. Porphyrin-based materials represent a particularly promising class of MOA-active compounds because of their inherent biocompatibility, tunable electronic properties, and compatibility with device-relevant functionalization. Metalated porphyrins with high MOA responses have already shown potential for magnetometry, where detecting minute magnetic fields requires strong magnetic orbital angular momentum contributions to alter absorption spectra in measurable ways. In previous work, the Rosenthal Group synthesized two A₄ and two A₂B₂ porphyrins to study how electron-withdrawing meso-substituents influence MOA in collaboration with the Rack Group at the University of New Mexico. The two different A4 porphyrins, 5,10,15,20-tetraphenylporphyrin (TPP) and 5,10,15,20-tetrapentafluorophenylporphyrin (TPFPP), are each symmetrical porphyrins where all four meso- positions of the porphyrin are modified with the same functional group. A2B2 porphrins, on the other hand, are a class of meso- substituted porphyrins where two pairs of meso- positions are occupied by two different types of functional groups (A and B). The cis- and trans-isomers containing pentafluorophenyl and phenyl substituents serve as a comparison to the A4 porphyrins proving how symmetry and electron withdrawing groups influence MOA. After metalating each of the derivatives with Zn²⁺, Ni²⁺, Pd²⁺, and Pt²⁺, the resulting porphyrins enabled systematic comparisons of metal size, π-backbonding, and electronic structure. The findings proved that electron-withdrawing substituents play a significant role in shaping magneto-optical response. To complete this systematic study of substituent patterns, the remaining A₃B and AB₃ porphyrins were synthesized and metalated each with Zn²⁺, Ni²⁺, Pd²⁺, and Pt²⁺. These derivatives will allow direct comparison of how incremental changes in electron-withdrawing substitution modulate MOA and metal–ligand interactions. Following successful synthesis and physical characterization of the molecules, the steady state spectroscopic properties of the complexes were analyzed. When looking at porphyrins for MOA it’s important to look at the Q0 band which is the lowest energy electronic transition within the Q-band region, typically appearing between 500 and 600 nm. It was found that the metallo- A3B porphyrin (M[A3BP]), having the least electron withdrawing meso substituents, had Q0 bands increasing from Zn²⁺ < Ni²⁺ < Pd²⁺ < Pt²⁺ but overall have very weak Q0 band absorption so low MOA is expected which closely mirrors the behavior reported for tetraphenylporphyrin (M[TPP]) derivatives. While the M[AB3P] derivatives having three pentafluorophenyl meso groups have Q₀ bands decreasing from Pt²⁺ > Ni²⁺ > Pd²⁺ > Zn²⁺, which is more consistent with the behavior observed in the metalated tetrakis(pentafluorophenyl)porphyrin (M[TPFPP]) derivatives proving that electron withdrawing groups play a role in modulating MOA.