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Intellectual Television Harms Relaxation, Games Help Us Detach? Different Attributes of Bedtime Media Are Associated With Multiple Types of Recovery
No full textThis article was originally published in Psychology of Popular Media. The version of record is available at: https://dx.doi.org/10.1037/ppm0000617
This work is licensed under a Creative Commons Attribution-Non Commercial-No Derivatives 4.0 International License (CC BY-NC-ND 4.0; https://creativecommons.org/licenses/by-nc-nd/4.0). This license permits copying and redistributing the work in any medium or format for noncommercial use provided the original authors and source are credited and a link to the license is included in attribution. No derivative works are permitted under this license.Using media to unwind after a long day is common, and empirical work shows that media use may aid recovery
from stress and strain. This study uses secondary data analysis of bedtime media diaries to examine how
various media types and content-related features may be associated with different recovery outcomes.
Results indicate that intellectually challenging media is negatively associated with relaxation, but this is
not the case for emotionally challenging media. We also see that video games (but not television or social
media) are positively associated with psychological detachment. Guilt about media use impedes several
recovery outcomes, and older participants report a greater sense of renewed control after using media at bedtime.
Taken together, this work provides some insight into how different forms of media may aid or impede
recovery outcomes and suggests several avenues for future development
Optical photothermal infrared response (O-PTIR) of functionalized thiophene monomers and polymers
No full textThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.Optical photothermal infrared response (O-PTIR) spectroscopy is an emerging technique of particular interest for examining the local chemistry and structure of organic molecular and polymer materials. Here, we used O-PTIR to examine the 3,4-ethylenedioxythiophene (EDOT) and maleimide-functionalized (EDOT-MA) monomers, and also thin films (~100 nm) of their corresponding polymers (PEDOT and PEDOT-MA) electrochemically deposited on interdigitated (5 μm) gold electrodes. The O-PTIR technique provided high-resolution (~ 1 μm) information about the chemical structure, including the ability to map local variations in the composition of the MA side groups. Certain limitations were found, particularly in samples that were strongly optically absorbing.Funding was provided through the University of Delaware’s discretionary fund given to David Martin, as well as by the Waters Corporation through their Immerse Delaware fund
The development of novel magnetic materials with distinct properties for spintronic technology
No full textXiao, John Q.Efficient switching of magnetization is a central challenge in spintronic technology. This thesis explores novel material platforms with enhanced performance, aiming to overcome key challenges such as the need for high charge-to-spin conversion efficiency and bias-free out-of-plane magnetization switching. Three classes of materials are systematically investigated: the noncollinear antiferromagnet Mn₃Sn, the heavy metal alloy RuₓPt₁₋ₓ, and altermagnetic RuO₂. Generation of unconventional polarized spin currents is demonstrated in Mn₃Sn, attributed to its cluster multipole structure. In the RuPt alloy system, structural phase evolution and spin Hall angle (SHA) variations are analyzed through X-ray diffraction and both MOKE and ST-FMR techniques, revealing a SHA 0.117 in 38% Ru composition. Lastly, the potential altermagnetic nature of RuO₂ is examined via cross-strip MOKE scanning, THz emission spectroscopy, and magnetic force microscopy. While no direct evidence of altermagnetism is observed, several unexplained phenomena suggest the presence of nontrivial thermoreflectance effects. This work not only introduces promising candidate materials for spintronic applications but also deepens the understanding of spin transport in complex magnetic systems.University of Delaware, Department of Physics and AstronomyPh.D
Group-V acceptors and compensation centers in CdTe
No full textJanotti, AndersonCadmium telluride (CdTe) is a leading thin-film material for photovoltaic applications. Owing to its high efficiency, cost-effectiveness, and scalability, CdTe-based solar cells are strong competitors to conventional silicon-based technology. These solar cells offer comparable efficiency with a simpler manufacturing process and a lower carbon footprint. Moreover, due to CdTe’s high absorption coefficient and direct band gap of 1.5 eV, the absorber layer can be significantly thinner than that of silicon, reducing material usages and production costs. ☐ The efficiency of CdTe-based solar cells has steadily improved, recently surpassing 23%. Further progress toward the theoretical limit of 33% remains an active area of research. A key challenge is enhancing p-type doping in the CdTe absorber layer. Group-V elements—P, As, and Sb—are commonly used to increase hole concentrations from the intrinsic level of ∼1014 to ∼1016 cm−3. However, doping efficiency is often low, with hole concentrations significantly lower than the dopant levels. The origin of this compensation remains unclear, though defects and grain boundaries are expected to play important roles in this low doping efficiency. ☐ This thesis investigates the role of defects, dopants, native defects, and their complexes, on carrier dynamics in CdTe. We employ first-principles calculations based on density functional theory (DFT) to study defect electronic structures. To accurately capture the band gap and band edge positions, hybrid DFT with spin-orbit coupling (SOC) is used. Calculations using the Heyd-Scuseria-Ernzerhof (HSE) hybrid functional with 33% Hartree-Fock mixing and SOC yield an improved description of the band structure, including a ∼0.3 eV shift in the valence band maximum due to relativistic effects from heavy Te atoms. ☐ The study first revisits group-V substitutional defects as acceptors. These shallow-level defects exhibit extended wavefunctions, leading to artificial interactions in finite-size supercells. To address this, ionization energies were extrapolated to the dilute limit using 64-, 216-, and 512-atom supercells. The extracted values of 93, 99, and 116 meV for P, As, and Sb, respectively, agree with temperature-dependent Hall measurements. Notably, AX centers, previously thought to be dominant compensation mechanisms, are shown to be unstable under typical doping conditions and thus unlikely to be major sources of compensation in group-V doped CdTe. ☐ The thesis then examines native point defects, focusing on their formation energies and migration barriers. While Cd interstitials are the lowest-energy donor defects, their low migration barriers make them unstable at room temperature. These interstitials are crucial for charge neutrality during high-temperature growth or annealing but tend to diffuse out upon cooling. Consequently, only more stable defects determine the material’s conductivity. Accounting for this in the charge neutrality equation yields carrier concentrations and conductivity types consistent with experimental data. In p-type doped samples, Cd interstitials may still be present in complex forms. ☐ One such complex involves group-V acceptors binding with Cd interstitials to form donor-type complexes that compensate for hole doping. Thermal annealing can dissociate these complexes, releasing Cd interstitials to the surface. The results suggest that annealing conditions are critical. Cd-rich environments favor complex formation, while Cd-poor conditions increase hole concentration. This complex explains experimentally observed trends in hole concentration and highlights its significant role in limiting doping efficiency in group-V doped CdTe. ☐ While group-V incorporation on Cd sites can also act as donor defects, they are not dominant under Cd-rich conditions, which is the most favorable environment for incorporating group-V atoms on Te sites and is commonly used in doping. The study also explores group-V pairing configurations, emphasizing the importance of using isolated dopant form as the doping source and controlling dopant concentrations. ☐ The analysis further highlights that the ionization energies of group-V acceptors (∼100 meV) are not-so-shallow compared to those of conventional shallow acceptors, contributing to lower doping activation at high dopant concentrations. ☐ Finally, the study extends to CdSeTe alloys. It is shown that group-V dopants can become deep acceptors in these materials. For example, the Sb acceptor level in CdSe0.25Te0.75 is found to lie 0.3–0.4 eV above the valence band maximum—significantly deeper than in CdTe—due to local structural distortions that break the ideal Td symmetry. ☐ In summary, this thesis provides new insights into doping and defect physics in CdTe. It demonstrates that group-V elements can serve as effective p-type dopants, given that doping and annealing conditions are carefully controlled. The findings underscore the importance of considering both defect formation energy and migration barrier in understanding defect stability. These results represent a critical step toward improving CdTe photovoltaic technology by enabling more effective doping strategies and a deeper understanding of defect behavior.University of Delaware, Department of Materials Science and EngineeringPh.D
Nanostructured iron and nickel oxide aerogels revolutionizing asphaltene removal in hydrocarbon processing
No full textThis article was originally published in Scientific Reports. The version of record is available at: https://doi.org/10.1038/s41598-025-95667-7.
© The Author(s) 2025.
Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.Asphaltenes, complex molecules in crude oil, cause significant challenges in oil production and refining due to their tendency to form agglomerates and precipitate. This study investigates the effectiveness of preparation method of metal oxide-based adsorbents (NiO and Fe2O3) in removing asphaltenes. Nanostructured NiO and Fe2O3 xerogels and aerogels were produced through the Pechini-type and epoxide-derived sol − gel methods and employed for the adsorption of Ap1, a specific asphaltene extracted from Iranian crude oil. The nanomaterials were characterized by XRD, N2 adsorption-desorption, FE-SEM, EDS, and FT-IR. The influence of synthesis parameters, including citric acid to metal precursor molar ratio, type of adsorbent, textural characteristics, adsorption temperature, sol-gel protocols, calcination temperatures, and drying conditions, on the adsorbent performance was systematically studied. The NiO(X-300) xerogel synthesized by the epoxide-derived sol − gel with calcination at 300 °C exhibited the highest asphaltene adsorption capacity (q = 558 mg/g) among all xerogels tested. This capacity was 102% and 87% higher than those achieved on optimized reference NiO(P-600) (q = 276 mg/g) and Fe2O3(P-600) (q = 298 mg/g) adsorbents prepared by the Pechini-type method, respectively. The textural properties of both NiO and Fe2O3 materials were improved upon supercritical CO2 drying of the epoxide-derived gels, leading to the nanostructured NiO(A-300) (q = 699 mg/g) aerogel with significantly higher (~ 135%) asphaltene adsorption capacity than Fe2O3(P-600). For the best aerogels, NiO(A-300) and Fe2O3(A-450), the adsorption isotherms and the kinetic data were best fitted by the Jovanovic and the Elovich models, respectively. Ap1 exhibited rapid adsorption onto NiO(A-300) and NiO(X-300), achieving equilibrium within 20 min. The adsorption process was demonstrably spontaneous and exothermic.This research did not receive dedicated funding from public, commercial, or nonprofit organizations
Reusing the News: Duplicating Local TV Content
No full textLocal U.S. television news provides citizens with crucial local information, particularly during periods of heightened political, social, or environmental salience. Yet local television news is under increased pressure to consolidate, which may serve to de-localize local news reporting by duplicating news content delivery across local broadcast stations.
This report examines two fundamental questions: (1) What is the state of ownership and/or control of local television stations across the 210 television markets in the U.S.? (2) Does that ownership/control affect news content and, if so, how?
We constructed three databases to address these questions. The databases span multiple characteristics of local broadcast stations and of the actual news content (i.e., transcript text) that each station aired. Our content database included the news broadcasts of 861 local stations in all 210 television markets in the U.S. that presented news content over a three-month period in the fall of 2019. It is the largest such database in existence. We chose a period before the COVID pandemic so that coverage was not affected by a single overwhelming story. We employed automated text reuse methods to measure the extent to which local broadcast station pairs duplicated (exact text reuse) each other’s news content. We applied a high threshold for duplication: to be considered duplication, 50% of the broadcast news content (excluding sports, weather and commercials) of a station pair had to be an exact match (text reuse).This research was supported by the James L. Knight Foundation (grants G-2021-63112 and G-2022-65201) and the Stavros Niarchos Foundation (SNF) Ithaca Initiative
AMERICAN BLACK BEAR (URSUS AMERICANUS) USE OF HIGHWAY UNDERPASSES IN NORTHERN NEW JERSEY
No full textenterThe state of New Jersey balances a large human population with associated
transportation infrastructure and urban development with an ecological diversity that
encompasses many species and habitat types. One key member of that ecological
diversity is the American black bear (Ursus americanus), a quintessential omnivore
found throughout the state despite many major roadways that could pose barriers to
movement and habitat connectivity. Here I examine black bear movement dynamics at
existing underpass structures of major roadways in Northern New Jersey. We
monitored 37 potential crossing structures along State Route 1, Interstate 78, Interstate
80, Interstate 95, State Route 202, and State Route 206, using trail cameras. My
findings suggest that the current North Atlantic Aquatic Connectivity Collaborative
metric used to assess underpasses for bear use may not accurately predict bear use, and
that habitat related factors, specifically the amount of core habitat in the area
surrounding each underpass, may provide a stronger predictive basis for where a bear
crossing might occur. These findings can be used to better inform the future placement
or enhancement of crossing structures for use by black bear. This will be important in
the continued management of human-wildlife conflict in the most densely population
state in the nation.ente
Coiled coil peptides as monomers for targeted self-assembly and crosslinking of nanostructured materials
No full textPochan, Darrin J.Proteins make excellent building blocks for materials creation due to their hierarchical self-assembly, sequence programmability, tunability, and diverse functionality. The sequence-defined precision of proteins enables programmable structure-function relationships, affording high levels of control of intra- and inter-molecular interactions. The ability to design, control, and tune the supramolecular self-assembly of peptides, which are short-length proteins, makes them well-suited for the design of nanostructured materials via a bottom-up approach. In this dissertation, I explore three fundamentals for the future design of peptide-based materials using coiled coil peptide ‘bundlemers’ as monomers: controllable covalent crosslinking, tunable and controllable physical assembly, and a scalable approach to peptide synthesis. The methods developed herein provide a platform for the bottom-up design of ordered materials made from peptide building blocks. ☐ Coiled coil peptide ‘bundlemers’ are computationally designed 29 amino acid peptides that self-assemble into tetrameric coiled coils in aqueous solution. These self-assembled structures resemble a cylinder-like particle with approximate dimensions of 2 nm in diameter and 4 nm in length. The particles are highly stable due to their well-designed hydrophobic core, and site-specific modifications can be easily made to the surface of the particles to allow for tunable interactions and controllable conjugation. ☐ First, bundlemer sequences were selectively modified with allyloxycarbonyl (alloc) protected lysines and cysteines for use in a thiol-ene photo click chemistry reaction to form crosslinked peptide networks. Results demonstrated that the degree of network crosslinking could be finely tuned by manipulating the number of crosslinkable sites and the position of those sites, providing control over intra- and interbundle crosslinking via the protein-like display of chemistry on the periphery of the particles. Adding the alloc protecting groups without cysteines resulted in unexpected particle self-assembly into highly ordered porous lattice structures. These lattices were studied experimentally using transmission electron microscopy (TEM) and small-angle x-ray scattering (SAXS), and lattice packing was proposed via machine learning optimization techniques. The proposed packing highlighted the importance of side-to-side interactions in the lattice self-assembly, which are driven via hydrophobic interactions between alloc side chains. ☐ The unexpected self-assembly of alloc-modified bundlemer sequences into intricate lattices inspired a new study utilizing new natural and non-natural hydrophobic amino acid side chains to drive self-assembly into lattice particles via similar interactions. I hypothesized that placing different hydrophobic side chains in identical positions along the peptide backbone would induce self-assembly into porous lattice particles, but with subtle differences in nanostructure. The same parent sequence was selectively modified with five new non-natural and natural hydrophobic amino acid side chains, and all modified sequences were observed to form porous lattice particles in solution that were distinctly different than the previously reported structures. New sequences were studied experimentally using TEM and SAXS and computationally via simulations and modeling to provide insight into the intra- and inter-particle interactions that drive lattice formation. These results highlighted the versatility of bundlemer design in forming precision nanoporous structures via hydrophobic interactions, the importance of spatial display of chemical functionality, and the role of molecular interactions that drive the formation of these nanostructures. ☐ Hydrophobic self-assembly of bundlemers into ordered lattices has proven tunable and robust for mixed charge peptide sequences. I hypothesized that making identical modifications to any bundlemer parent sequence should enable self-assembly into lattice particles via hydrophobic interactions. Due to their different amino acid composition, single charge bundlemer sequences were chosen for modification, which are unique because they exhibit liquid crystalline behavior at high concentrations in aqueous solution, driven by electrostatic interactions. Modifying single charge sequences with alloc protected lysines enabled the functional design of a polymorphic peptide particle capable of forming hexagonal columnar liquid crystals in aqueous suspension and crystal lattice particles in concentrated salt solutions. Uniquely, despite having a very different amino acid composition, one of the new modified sequences had nearly identical bundlemer packing to the previously studied mixed charge alloc lattices, as observed via structure factor in SAXS. The observation of identical structures across two very different peptide sequences highlights the importance of the display of the alloc groups on the periphery of the bundlemer particles and the specificity of their interactions in forming ordered lattices. ☐ One overarching challenge of my research was the limitation in the amount of material for bulk materials crosslinking and characterization. To alleviate this, I turned to recombinant expression in E. coli to synthesize large quantities of peptide. A protocol for synthesizing and purifying coiled coil peptide multimers has been developed for scalable synthesis, focusing on the tagless expression and column-less purification of these multimeric proteins. Without chromatography, solution conditions such as pH, temperature, and salt concentration are to manipulate solubility and drive separation via controllable phase behavior. This dissertation includes an in-depth discussion of the design, synthesis, purification, and characterization of the coiled coil multimers and future directions for recombinant expression.University of Delaware, Department of Mathematical SciencesPh.D
EVALUATING ROADKILL HOTSPOTS IN NORTHERN NEW JERSEY
No full textMcCarthy, KyleMillions of mammals are killed each year by vehicles, and while there is oftentimes bias in recording larger mammalian roadkill, these species have become crucial in analyzing roadkill hotspots. With the growing human population and increased pressures of urban development, the state of New Jersey provides an excellent opportunity to understand the factors that affect roadkill events. I examine American black bear, white-tailed deer, and coyote roadkill events in combination with randomly generated roadkill points in northern New Jersey. We focused on seven different covariates, including NAACC terrestrial passage score, nearby agriculture and urban habitat, nearby core and corridor habitat, distance to the nearest core/corridor area, and distance to the nearest culvert or underpass structure. My findings suggest that the percent agricultural and percent urban habitat within a 10km2 radius of each event point were most significant in describing roadkill events. In all six models, the percent urban area was negatively correlated with roadkill events, while the percent agricultural area was also negatively correlated with roadkill events, but only significant in the first model. For bear roadkill events, the percent core and corridor showed a significant positive relationship, with more roadkill events occurring near core and corridor areas. In these same bear models, the distance to the nearest core or corridor was negatively correlated with roadkill events. The distance to the nearest culvert and NAACC terrestrial passage scores were not good indicators of roadkill events for any of the three species, most likely due to culverts rarely explaining roadkill on their own. These findings can be used to better evaluate landscape and habitat importance in roadkill events and evaluate existing underpass placements to facilitate terrestrial species movement across the state of New Jersey.Senior Thesis Progra
FORMING GENOME TO PHENOME CONNECTIONS: BACTERIOPHAGE REPLICATION GENES
No full textenterViruses are the most genetically diverse and environmentally abundant
biological entities, however they are vastly understudied. Viral impacts on host
communities and ecosystems can be differentiated by distinct infection dynamics.
Lytic viruses lyse the host during infection, affecting nutrient cycling and community
composition. Temperate viruses incorporate their genomes into hosts during infection,
contributing to horizontal gene transfer and affecting host biology. DNA polymerase I
(PolA) is carried by many bacteriophages (bacterial viruses) and may be linked with
infection dynamics phenotypes. Variations in the PolA 526 residue (T7 numbering)
influence the speed and accuracy of DNA replication, a vital infection process. Three
previously identified 526 residues—phenylalanine, tyrosine, and leucine—influence
enzyme biochemistry and phage infection phenotypes. Faster replicating Phe526 or
Tyr526 PolAs tend to be found in lytic phage, while slower replicating Leu526 PolAs
are largely found in temperate phage. A novel histidine 526 variant has been identified
in oceanic viral metagenomes (viromes). In vitro biochemical analysis and in vivo
mutagenesis studies showed that His526 PolAs have hindered processivity and phage
T7 mutants encoding the His526 variant replicate slower. Bioinformatic analysis of
viromes show contextual differences in His526 PolAs that predominate in different
depths in oligotrophic ocean samples by sequence variation, as well as different
requirements for additional replication proteins. This study aims to strengthen the
PolA genome to phenome hypotheses and aid in predicting the infection strategies of
His526 viral populations to understand their impacts on ecosystem.ente