31825 research outputs found
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Correlating climate phenomena and crustal shear wave velocity changes using ambient seismic noise
No full textLynner, ColtonPrevious studies have used seismic ambient noise to calculate how relative seismic velocities change over time, which can provide a way of monitoring volcanic activity. However, precipitation and other meteorological activity can affect seismic velocities, obscuring potential volcanic signals. This study seeks to understand how meteorological activity and seismic velocity changes interact at Akutan Volcano in Alaska between 2019 and 2024. We use MSNoise, a Python module, to cross-correlate transverse and vertical components for 10 seismic stations and calculate relative velocity changes. Both transverse and vertical components are used to characterize how elastic load from precipitation, atmospheric pressure, and other meteorological activity impact both horizontal and vertical cracks in the crust. Seasonal relative velocity changes are observed, with velocity decreases occurring in the winter months and velocity increases in the spring and summer. When temperature is compared with relative velocity changes, velocity increases are shown to occur in the high frequencies when the minimum temperature is below 0°C at a nearby coastal weather station. Modelled subsurface water runoff closely resembles the asymmetric overall shape of the relative velocity changes, suggesting a possible linkage. We also compared relative velocity changes with GPS data and large seismic events with little success.University of Delaware, Department of Earth SciencesM.S
Opposing views on teacher professionalism: institutionalist versus fiduciary, authorial professionalism
No full textMatusov, EugeneThis dissertation critically examines the concept of responsibility within competing models of teacher professionalism: institutionalist professionalism and authorial professionalism. Drawing from a case study with ethnographic elements, it explores how institutionalism mandates structure teacher accountability in ways that constrain professional autonomy, contrasting this with a model in which teachers are responsible for their students’ educational journeys as unique dynamic and authorial processes. Using captured dialogue as research art, this study documents the lived experiences of a high school social studies teacher, Pete, who has a complex and sometimes conflicting relationship with his institutionalist administrators. Pete’s authorial professionalism challenges institutionalist expectations that prioritize compliance with an ideology for preset teaching practices over his authorial style that is responsive to his students’ emerging interests and desires. The research situates this tension within broader philosophical and sociological discussions about the notion of “professionalism” and its relationship to the moral concern of responsibility. Engaging with the works of Bakhtin, Weber, Arendt, Flexner, Kant, Goffman, Matusov, and others, it argues that institutionalist professionalism, rooted in bureaucratic rationalization and performative accountability, externalizes responsibility, reducing the teacher to a mere implementer of standardized practices. In contrast, authorial professionalism demands an ethical and intellectual responsibility, where the teacher, as an autonomous professional, is central to the pedagogical decisions in the contexts in which they are implemented. Through qualitative analysis of state code and other official rhetoric, a teacher evaluation and educator discourse, this study investigates how institutional structures shape and constrain professional practice, ultimately advocating for a reconceptualization of teacher responsibility that foregrounds professional authorship, moral agency, and the unpredictability of genuine responsibility in education.University of Delaware, School of EducationPh.D
Biochemical mapping reveals a conserved heme transport mechanism via CcmCD in System I bacterial cytochrome c biogenesis
No full textThis article was originally published in mBio. The version of record is available at: https://doi.org/10.1128/mbio.03515-24.
© 2025 Kreiman et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0/).
This research was featured in UDaily on 5/19/2025 at: https://www.udel.edu/udaily/2025/may/lab-mentorship-undergraduate-publications-sarah-garner-molly-sutherland/Heme is a redox-active cofactor for essential processes across all domains of life. Heme’s redox capabilities are responsible for its biological significance but also make it highly cytotoxic, requiring tight intracellular regulation. Thus, the mechanisms of heme trafficking are still not well understood. To address this, the bacterial cytochrome c biogenesis pathways are being developed into model systems to elucidate mechanisms of heme trafficking. These pathways function to attach heme to apocytochrome c, which requires the transport of heme from inside to outside of the cell. Here, we focus on the System I pathway (CcmABCDEFGH) which is proposed to function in two steps: CcmABCD transports heme across the membrane and attaches it to CcmE. HoloCcmE then transports heme to the holocytochrome c synthase, CcmFH, for attachment to apocytochrome c. To interrogate heme transport across the membrane, we focus on CcmCD, which can form holoCcmE independent of CcmAB, leading to the hypothesis that CcmCD is a heme transporter. A structure-function analysis via cysteine/heme crosslinking identified a heme acceptance domain and heme transport channel in CcmCD. Bioinformatic analysis and structural predictions across prokaryotic organisms determined that the heme acceptance domains are structurally variable, potentially to interact with diverse heme delivery proteins. In contrast, the CcmC transmembrane heme channel is structurally conserved, indicating a common mechanism for transmembrane heme transport. We provide direct biochemical evidence mapping the CcmCD heme channel and providing insights into general mechanisms of heme trafficking by other putative heme transporters.
IMPORTANCE
Heme is a biologically important cofactor for proteins involved with essential cellular functions, such as oxygen transport and energy production. Heme can also be toxic to cells and thus requires tight regulation and specific trafficking pathways. As a result, much effort has been devoted to understanding how this important, yet cytotoxic, molecule is transported. While several heme transporters/importers/exporters have been identified, the biochemical mechanisms of transport are not well understood, representing a major knowledge gap. Here, the bacterial cytochrome c biogenesis pathway, System I (CcmABCDEFGH), is used to elucidate the transmembrane transport of heme via CcmCD. We utilize a cysteine/heme crosslinking approach, which can trap endogenous heme in specific domains, to biochemically map the heme transport channel in CcmCD, demonstrating that CcmCD is a heme transporter. These results suggest a model for heme trafficking by other heme transporters in both prokaryotes and eukaryotes.We thank Robert G. Kranz for generous use of strains and plasmids (indicated by pRGK designations in Table S2). We acknowledge Robert G. Kranz and the Washington University in St. Louis Fall 2017 Bio437 class for cloning of some CcmCD cysteine variants. We thank Donna R. Price and Kristelle Juhasz for technical assistance.
Research reported in this publication was supported by the National Institute of General Medical Sciences of the National Institutes of Health under award number R35GM142496 to M.C.S. and T32GM133395 to A.N.K. S.E.G was supported by the Delaware INBRE program with a grant from NIH-NIGMS (P20 GM103446) and the State of Delaware. Additional support was provided by the University of Delaware Doctoral Fellowship for Excellence to A.N.K. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health
A bio-inspired approach to engineering water-responsive, mechanically-adaptive materials
No full textThis article was originally published in Molecular Systems Design & Engineering. The version of record is available at: https://doi.org/10.1039/D4ME00177J.
© The Royal Society of Chemistry and IChemE 2025.
This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence (http://creativecommons.org/licenses/by-nc/3.0/).Inspired by a diverse array of hierarchical structures and mechanical function in spider silk, we leverage building blocks that can form non-covalent interactions to develop mechanically-tunable and water-responsive composite materials via hydrogen bonding modulation. Specifically, self-assembling peptide blocks consisting of poly(β-benzyl-l-aspartate) (PBLA) are introduced into a hydrophilic polyurea system. Using these peptide–polyurea hybrids (PPUs) as a hierarchical matrix, cellulose nanocrystals (CNCs) are incorporated to diversify the self-assembled nanostructures of PPUs through matrix–filler interactions. Our findings reveal that higher PBLA content in the PPUs reduces the magnitude of the stiffness differential due to the physical crosslinking induced by the peptide blocks. Additionally, the inclusion of CNCs in the PPU matrix increases the storage modulus in the dry state but also diminishes the wet-state modulus due to the shift of physical associations from peptidic arrangements to PBLA–CNC interactions, resulting in variations in the morphology of the PPU/CNC nanocomposites. This molecular design strategy allows for the development of adaptable materials with a broad range of water-responsive storage modulus switching , spanning from ∼70 MPa to ∼400 MPa. This investigation highlights the potential of harnessing peptide assembly and peptide–cellulose interactions to achieve mechanical enhancement and water-responsiveness, providing insights for engineering next-generation responsive materials.Financial support for this research was provided by the National Science Foundation (NSF) PIRE: Bio-inspired Materials and Systems [OISE 1844463]. DMA studies were supported as part of the Center for Plastics Innovation, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under award DE-SC0021166, for the use of RSA-G2 instrument. AFM access was supported by the Delaware INBRE program, with grants from the NIH-NIGMS (#P20 GM103446) and the State of Delaware, and it was provided by the BioImaging Center at the University of Delaware. Access to the ATR-FTIR, DSC, and SAXS was provided by the Advanced Materials Characterization Laboratory (AMCL) at the University of Delaware. We thank https://www.BioRender.com for providing tools that facilitated the creation of several figures included in this manuscript
The Benefits of Working with a University Press to Establish a Library Publishing Program: Case Studies from Temple University and the University of Delaware
No full textThe Association of University Presses (AUP) is a community of publishing professionals with over 150 global members. AUP is a strategic affiliate of the Library Publishing Coalition, and the two organizations regularly communicate with one another and attend each other’s annual meetings. The strong ties between these organizations make sense, in part because over the past fifteen years a growing number of university presses have begun reporting to their institution’s library. While more publishers reporting to libraries has led to some notable collaborations, ongoing working relationships and joint services are still not the norm. This is unfortunate, because university presses and libraries are part of a vital campus-based knowledge infrastructure that serves faculty, students, and the public, and working together has the potential to benefit both groups. This chapter argues that library publishers, and libraries wishing to start a library publishing program, should look to their institution’s university press for help along the way
Stuttering: Our Current Knowledge, Research Opportunities, and Ways to Address Critical Gaps
No full textThis article was originally published in Neurobiology of Language. The version of record is available at: https://doi.org/10.1162/nol_a_00162.
© 2025 Massachusetts Institute of Technology. Published under a Creative Commons Attribution 4.0 International (CC BY 4.0) license.
This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. For a full description of the license, please visit https://creativecommons.org/licenses/by/4.0/legalcode.Our understanding of the neurobiological bases of stuttering remains limited, hampering development of effective treatments that are informed by basic science. Stuttering affects more than 5% of all preschool-age children and remains chronic in approximately 1% of adults worldwide. As a condition that affects a most fundamental human ability to engage in fluid and spontaneous verbal communication, stuttering can have substantial psychosocial, occupational, and educational impacts on those who are affected. This article summarizes invited talks and breakout sessions that were held in June 2023 as part of a 2-day workshop sponsored by the US National Institute on Deafness and Other Communication Disorders. The workshop encompassed topics including neurobiology, genetics, speech motor control, cognitive, social, and emotional impacts, and intervention. Updates on current research in these areas were summarized by each speaker, and critical gaps and priorities for future research were raised, and then discussed by participants. Research talks were followed by smaller, moderated breakout sessions intended to elicit diverse perspectives, including on the matter of defining therapeutic targets for stuttering. A major concern that emerged following participant discussion was whether priorities for treatment in older children and adults should focus on targeting core speech symptoms of stuttering, or on embracing effective communication regardless of whether the speaker exhibits overt stuttering. This article concludes with accumulated convergent points endorsed by most attendees on research and clinical priorities that may lead to breakthroughs with substantial potential to contribute to bettering the lives of those living with this complex speech disorder.Jennifer Below, National Institute on Deafness and Other Communication Disorders (https://dx.doi.org/10.13039/100000055), Award ID: R01DC017175. Jennifer Below, National Institute on Deafness and Other Communication Disorders (https://dx.doi.org/10.13039/100000055), Award ID: R03DC015329. Soo-Eun Chang, National Institute on Deafness and Other Communication Disorders (https://dx.doi.org/10.13039/100000055), Award ID: R01DC011277. Soo-Eun Chang, National Institute on Deafness and Other Communication Disorders (https://dx.doi.org/10.13039/100000055), Award ID: R01DC018283. Ho Ming Chow, National Institute on Deafness and Other Communication Disorders (https://dx.doi.org/10.13039/100000055), Award ID: R21DC015853. Frank Guenther, National Institute on Deafness and Other Communication Disorders (https://dx.doi.org/10.13039/100000055), Award ID: R01DC007683. Nan Bernstein Ratner, National Institute on Deafness and Other Communication Disorders (https://dx.doi.org/10.13039/100000055), Award ID: R01DC015494. Nan Bernstein Ratner, National Institute on Deafness and Other Communication Disorders (https://dx.doi.org/10.13039/100000055), Award ID: R01DC307764. Bridget Walsh, National Institute on Deafness and Other Communication Disorders (https://dx.doi.org/10.13039/100000055), Award ID: R03DC013402. Bridget Walsh, National Institute on Deafness and Other Communication Disorders (https://dx.doi.org/10.13039/100000055), Award ID: R01DC018000. Ludo Max, National Institute on Deafness and Other Communication Disorders (https://dx.doi.org/10.13039/100000055), Award ID: R01DC017444. Ludo Max, National Institute on Deafness and Other Communication Disorders (https://dx.doi.org/10.13039/100000055), Award ID: R01DC020707. Amanda Hampton Wray, National Institute on Deafness and Other Communication Disorders (https://dx.doi.org/10.13039/100000055), Award ID: R21DC017227. Amanda Hampton Wray, National Institute on Deafness and Other Communication Disorders (https://dx.doi.org/10.13039/100000055), Award ID: R01DC019904. Shahriar SheikhBahaei, National Institute of Neurological Disorders and Stroke (https://dx.doi.org/10.13039/100000065), Award ID: ZIA NS009420. Nan Bernstein Ratner, National Stuttering Association, Award ID: CASE grant. Nan Bernstein Ratner, National Science Foundation (https://dx.doi.org/10.13039/100000001), Award ID: BCS1626300. Kate Watkins, Medical Research Council (https://dx.doi.org/10.13039/501100000265), Award ID: MR/K023772/1 and MR/N025539/1. Kate Watkins, NIHR Oxford Biomedical Research Centre (https://dx.doi.org/10.13039/501100013373), Award ID: NIHR203316. Kate Watkins, Wellcome Trust (https://dx.doi.org/10.13039/100010269), Award ID: 203139/Z/16/Z and 203139/A/16/Z. National Institute on Deafness and Other Communication Disorders (https://dx.doi.org/10.13039/100000055), Award ID: R01DC00559
Comprehensive Analysis of Hearing Function in Morquio A Syndrome: Implications for Diagnosis and Management
No full textenterMorquio A syndrome (Mucopolysaccharidosis IVA or MPS IVA) is a rare lysosomal
storage disorder characterized by systemic skeletal dysplasia and progressive multi organ involvement. Its effects on hearing function are a common, yet under characterized, clinical manifestation of this disorder. Previous studies have noted the
presence of mixed, conductive, and sensorineural hearing loss in patients with MPS
IVA, but few have systematically examined auditory function using comprehensive
behavioral and objective measures. This thesis investigates the auditory phenotype of
individuals with Morquio A using the largest cohort assembled to date, with data
collected through the Nemours Skeletal Dysplasia Lab. Auditory assessments included
pure-tone thresholds (PTA), speech-recognition threshold (SRT), speech perception in
quiet and noise (SIQ and SIN), tympanometry, otoacoustic emissions (DPOAEs),
auditory brainstem responses (ABRs), and cortical auditory evoked potentials
(CAEPs). These measures were used to determine the prevalence, type, and severity of
hearing loss and to explore potential correlations with age, MPS IVA disease severity,
and auditory system involvement. We found that the prevalence of hearing loss in this
study population was 50.88% with a higher prevalence of sensorineural hearing loss
over mixed and conductive types. There were no significant correlations found
between hearing loss severity and disease severity or age at diagnosis. These findings
suggest that hearing loss in MPS IVA patients may be affected by peripheral and
central auditory system dysfunction. Due to the complex characterization of hearing
loss in patients with MPS IVA, routine and comprehensive auditory evaluations are
critical for early intervention and mitigation of its impact on communication and
quality of life.ente
Political economy of space development in Africa
No full textKlinger, Julie MichelleSpace has become a pivotal instrument for development and international diplomacy in Africa, given its significant cultural, social, and economic impacts. Despite this, existing literature on African development largely neglects the space sector, while the growing body of research on the political economy of space often overlooks Africa. This omission is a critical gap, as it disconnects development theories and policies from the realities of Africa's science and technology landscape. Additionally, it provincializes global theories on the political economy of space by ignoring Africa's role in the development of the global space arena. This study addresses these gaps by analyzing the political economy of space development in Africa, offering a historical perspective on the continent's space initiatives, examining the influence of leadership and governance, and exploring Africa's international space relations with China, Europe, Russia, the United States, and international organizations. This study concludes that space activities are not new to Africa, having existed across multiple scales, and that the development of space programs on the continent is driven by socioeconomic and sustainable development goals. It suggests that governance at various levels significantly influences space development outcomes in Africa and that foreign interest initially arose from Europe’s need for external markets. The study argues that foreign institutional involvement often hampers Africa's growth in this sector, whereas China has emerged as Africa’s primary partner in space development. Additionally, it critiques prevailing ideologies surrounding African space initiatives and proposes a new foundational perspective for the continent’s space programs. ☐ Between 2021 and 2023, the primary research methodology employed was auto-ethnography (Ellis, 2011; Mendez, 2013), which intertwined my personal experiences with the cultural dynamics of the research process. Complementary methods included desktop and archival research (Luker, 2008), participant observation (Cerwonka & Malkki, 2007; Luker, 2008), structured and unstructured interviews, institutional policy engagements (Blaikie, 1985), and fieldwork (Cerwonka & Malkki, 2007; Luker, 2008). Qualitative and quantitative data were analyzed using Power BI and Tableau. From 2021 to 2024, I conducted participant observation at conferences and workshops in seven countries, engaged in forums and closed-door meetings in six, and pursued institutional policy work in four countries, including engagements with the Global Satellite Operators Association and the U.S. Institute of Peace. Fieldwork conducted between 2022 and 2024 spanned Angola, Ethiopia, Ivory Coast, Kenya, Nigeria, Senegal, and Rwanda, visiting multiple institutions such as space agencies, private firms, and regional organizations. ☐ This study advances existing work on development in Africa, existing work on global political economy research and existing work on the political economy of space leveraging auto-ethnography research method. It provides historical analysis contributing to existing body of work on space development in Africa while correcting existing misinformation and assumptions. Furthermore, it constitutes a major contribution to empirical research on space development globally and in Africa and provides the first holistic view into the political economy of space development in Africa, providing a critical contribution to advance both development and political economy theories and discourses. Finally, it provides a critical analysis of various political economic theories, evaluating their weaknesses and strength in explaining the space development landscape in Africa.University of Delaware, Department of Geography and Spatial SciencesPh.D
Influence of boron-containing dopants on the structure and electrochemical properties of poly(3,4-ethylene dioxythiophene) (PEDOT)
No full textThis article was originally published in Journal of Materials Science. The version of record is available at: https://doi.org/10.1007/s10853-025-11477-2
This 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/.The choice of doping agents used during electrochemical polymerization is a crucial factor affecting the ultimate performance of poly(3,4-ethylenedioxythiophene) (PEDOT) thin films. Boron-containing dopants are a versatile group of materials that make it possible to conveniently tune PEDOT film structure and properties. Here, we investigated how several boron-containing dopants affect the structure and properties of electrodeposited PEDOT. The dopants examined were sodium tetrafluoroborate (NaBF4), sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaTFPB), and sodium tetraborate (Na2B4O7, Borax). We compared these results to a commonly used non-boron-containing dopant for PEDOT, lithium perchlorate (LiClO4). After electrodeposition, overall rough PEDOT film surfaces with varied morphological features, depending upon the utilized dopants were generated based on SEM. The low-frequency impedances of all PEDOT-coated electrodes were at least one order of magnitude lower than those of bare electrodes. The lowest impedances were observed for PEDOT/ClO4 and PEDOT/BF4, correlated with their doping levels by reaching the maximum threshold of 33%. These two also had similar and higher areal-specific capacitances with the values of 9.4 and 10.3 mF/cm2 than those of PEDOT/TFPB (3.3 mF/cm2) and PEDOT/B4O7 (0.2 mF/cm2) on smooth gold surfaces. Although their areal-specific capacitances were similar, the volumetric-specific capacitance of PEDOT/BF4 was 284 F/cm3 and almost doubled that of PEDOT/ClO4. For screen-printed electrodes, the areal-specific capacitance of PEDOT/TFPB was almost similar to the other two types, with the values of approximately 6.0 mF/cm2. We also demonstrated that PEDOT/TFPB is a particularly promising material with comparable properties and better cyclic stability.This research was supported financially by the Turkish National Boron Research Institute (BOREN) and the University of Delaware. The main mission of BOREN is to widen the range of applications for boron products and contribute to scientific studies in the development of new boron-based products. In this study, we incorporated boron-based materials into the applications of CPs, especially for PEDOT which is an important part of organic semiconductors