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Mechanical structure-function relationships in the cerebral cortex
No full textWang, LiyunJohnson, Curtis L.The structure and function of the brain are intrinsically linked, as changes in cognition correspond with known periods of structural remodeling across the lifetime of a person. This relationship is even more prevalent in neurodevelopmental conditions and neurodegenerative diseases, where changes in brain structure accompany disease symptoms and abnormal cognitive function. The cortex, a brain region responsible for higher-level executive functions like personality expression and decision making, is disproportionately impacted by common neurological conditions, with large amounts of degradation found in cortical areas. The study of cortical structure and its impact on function is dominated by measures of volume and thickness because the cortex is easily identifiable on standard structural images as the exterior gray matter of the brain. Findings from these studies have highlighted volume loss through healthy aging, cortical thinning during development, and accelerated changes in the cortical structure with dementia and Alzheimer’s disease. However, volumetric measures are unable to provide high levels of sensitivity to structural changes in the brain because they are an indirect measure of the microstructure itself. ☐ A new technique for quantifying in vivo microstructural properties of brain tissue was recently developed called magnetic resonance elastography (MRE). MRE measures the mechanical properties of brain tissue to characterize tissue viscoelastic behavior through two properties of interest, shear stiffness and damping ratio. Taken together these properties can capture changes in tissue composition and organization, both of which have provided increased sensitivity and additional insight into the structure-function relationship in the brain. In previous studies, MRE measures have been linked to memory and cognitive performance, including studies where volume was not a significant predictor of cognition. Research applications of cortical MRE measures have been limited due to resolution and processing techniques that were unable to accurately resolve properties over the geometrically complex and thin structure. ☐ This thesis aims to apply improved mechanical property recovery techniques to characterize the structure-function relationship in the cortex, addressing this research gap through three aims. The first aim is focused on determining aging effects on cortical mechanical properties during normal aging and their relationship to cortical controlled cognitive function. The goal of the second aim is to quantify longitudinal change in adolescent tissue mechanical properties, particularly the cortex, and determine how these changes relate to pubertal progression. Lastly, the third aim investigates the network relationship of mechanical properties in the cortex and association of network properties to cognitive performance. Together, this thesis highlights the utility of MRE to measure structural changes in the cortex and as a promising technique to sensitively study the cortical structure-function relationship.University of Delaware, Department of Mechanical EngineeringPh.D
The Emerging Regulatory Landscape of Unmanned Aircraft Systems
No full textUnmanned Aircraft Systems (UASs)—including Unmanned Aerial Vehicles (UAVs), Remotely Piloted Aircraft Systems (RPASs), and drones—are transitioning from a futuristic concept to a nascent commercial reality. Given that the Federal Communications Commission (FCC) projects the estimated number of drones in the United States to triple from two million to six million between 2021 and 2030,1 UASs have immense economic and societal potential. While not yet ubiquitous, UAS services operate in select markets, driven by advancements in automation, battery technology, and a gradually maturing regulatory framework. UAS technology promises to revolutionize industries such as precision agriculture, infrastructure inspection, emergency response, and retail. Relative to logistics the primary focus is on the “last mile,” with UAS use aimed at delivering small, high-value packages faster and more efficiently than traditional ground transport. The critical challenge of adopting this technology hinges on the safe and effective integration of these aircraft into society. This requires a complex, multi-layered regulatory approach, with federal, state, and local governments playing a crucial role in shaping the future of drone use.
The Freight Futures series examines the disruptive technologies and evolving regulatory frameworks that are reshaping the modern landscape of logistics and transportation.The Institute for Public Administration prepared this brief with funding support from the Delaware Department of Transportation
Reading Strategically: Comparing the Use of Metacognitive Strategies in L1 University and L2 IEP Students
No full textThis article was originally published in EnglishUSA Journal. The version of record is available at: https://surface.syr.edu/englishusa_journal/vol11/iss1/6.
The EnglishUSA Journal is an open access journal, which means all its content is freely available without charge to the user or his/her institution. EnglishUSA operates under the Creative Commons Attribution 4.0 International License CC-BY (https://creativecommons.org/licenses/by/4.0/). This allows others distribute, remix, tweak, and build upon the work, as long as they credit the authors for the original creation. All authors publishing in EnglishUSA accept these as the terms of publication.
Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons 4.0 License which allows others to share the work with an acknowledgment of the work's authorship and initial publication in this journal.In this study, we explored the use of reading metacognitive strategies of 133 college students, comparing the self-reported use of L1 and L2 English students. Results indicate that while both groups report using strategies often when reading academic texts and having similar preferences in types of reading strategy, L2 readers use strategies more frequently than their native-speaking peers, particularly for support strategies
A Perceptual Model of Drivers and Limiters of Coastal Groundwater Dynamics
No full textThis article was originally published in Hydrological Processes. The version of record is available at: https://doi.org/10.1002/hyp.70058.
© 2025 The Author(s). Hydrological Processes published by John Wiley & Sons Ltd.
This is an open access article under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits use, distribution and reproduction in any medium, provided the original work is properly cited.Coastal groundwater is a vital resource for coastal communities around the globe, and submarine groundwater discharge (SGD) delivers nutrients to coastal marine ecosystems. Climatic changes and anthropogenic actions alter coastal hydrology, causing seawater intrusion (SWI) globally. However, the selection of SWI and SGD study sites may be highly biased, limiting our process knowledge. Here, we analyse hydroenvironmental characteristics of coastal basins studied in 1298 publications on SGD and SWI to understand these potential biases. We find that studies are biased towards basins with gross domestic product per capita below (SWI) and above (SGD) the median of all global coastal basins. Urban coastal basins are strongly overrepresented compared to rural coastal basins, limiting our progress in understanding undisturbed natural processes. Despite the connection between anthropogenic activity and coastal groundwater issues, and the consequential overrepresentation of urban basins in coastal groundwater studies, perceptual (or conceptual) models of coastal groundwater rarely include anthropogenic influences aside from pumping (e.g., subsidence, land use change). Taking a holistic view on coastal groundwater flows, we have developed an editable perceptual model illustrating the current understanding, including both natural and anthropogenic drivers. As SGD and SWI in new areas of the globe are studied, we advocate for researchers to utilise and further edit this perceptual model to openly communicate our process understanding and study assumptions.D.V.K. is funded by Deutsche Forschungsgemeinschaft (GZ: RE 4624/1-1). R.R. and T.W. were funded by the Alexander von Humboldt Foundation in the framework of the Alexander von Humboldt Professorship endowed by the German Federal Ministry of Education and Research. H.A.M. was funded by the US National Science Foundation Coastal Critical Zone project (EAR2012484). M.F.P.B. was funded by the ERC Advanced Grant Scheme (project GEOWAT no. 101019185)
Problematic social media use in 3D? Relationships between traditional social media use, social virtual reality (VR) use, and mental health
No full textThis article was originally published in PLoS ONE. The version of record is available at: https://doi.org/10.1371/journal.pone.0314863.
© 2025 Yao et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.This research expanded on prior work exploring the relationship between social media use, social support, and mental health by including the usage of social virtual reality (VR). In Study 1 (undergraduate students; n = 448) we examined divergent relationships between problematic social media use (e.g., Facebook, TikTok), total use, and users’ mental health indicators (e.g., depression, anxiety, social isolation). To determine whether problematic social media use patterns extended to immersive 3-D environments, we sampled active social VR users (e.g., Rec Room) in Study 2 (n = 464). Problematic social VR use was related to decreased real-life social support (β = -.62, 95%CI [-.80, -.44]), but not to VR social support (β = -.06, 95%CI [-.25, .14]). Conversely, the amount of social VR use was only related to increased social VR (β = .06, 95%CI [.04, .15]) but not to real-life social support (β = -.02, 95%CI [-.05, .04]). Study 2 also revealed a finding that may be unique to the 3-D immersive environment: the amount of social VR use facilitated better mental health for VR users, but only through stronger perceived social support on social VR but not in real life. This result highlights the potential of immersive media to promote mental well-being by facilitating engaging and meaningful social interactions.The first author's startup fund from Georgia State University was used to fund this research
Structure, rheology, and phase behavior of protein formulations under high pressure
No full textWagner, Norman J.Furst, Eric M.Lenhoff, Abraham M.High hydrostatic pressure (HP), defined as pressures between 100 MPa - 800 MPa, is an increasingly prevalent component of protein formulation processing for foods and pharmaceuticals. HP is found across the process development scheme, including extraction and purification of drug substances via cell disruption, freeze-thaw cycling of liquid therapeutic drug products during storage, pressure-inactivation of cell-based and virus-based assays for vaccine manufacturing, and non-thermal sterilization. HP can have significant effects on the stability, rheological properties, and phase behavior of protein formulations, yet despite the wide usage of HP in industrial processing, little is known about the mechanistic effects of HP on protein intermolecular behavior, formulation properties, or phase behavior. The major barrier to developing predictive models for HP protein behavior is a lack of available in situ HP protein data, which itself stems from the limited availability of in situ characterization approaches for structure, rheology, and phase behavior under HP. Therefore, the research in this dissertation is motivation primarily by two goals: an expanded understanding of the mechanistic effects of HP on protein behavior by building structure-property relationships across multiple length scales, and an expansion upon current HP analytical capabilities to provide better tools for formulation screening under HP. ☐ First, we apply HP small-angle X-ray scattering (HP-SAXS) to investigate the simultaneous effects of HP and dissolved salt on ovalbumin intermolecular interactions. Interaction trends are quantified by the reduced second virial coefficient and a synergistic effect is observed, with enhanced net attraction with either increasing ionic strength or applied pressure. A significant contribution of the work in this dissertation, inspired by the apparent pressure-salt synergism, is a new semi-empirical model which captures the effects of both pressure and ionic strength with a single effective pressure parameter. Applying the model results in smooth alignment of interaction data to a master curve across a wide range of applied pressures and ionic strengths. The model is then applied to protein data in the literature, and the correlation is shown to apply broadly but not universally to other protein-salt systems. Importantly, the synergism with ion effects strongly supports a hydration-driven mechanism of pressure-induced protein-protein attraction and provides critical insight into the mechanistic effects of pressure on protein stability. ☐ We also investigate the effects of pressure holding time on the semi-empirical master curve, using HP small-angle neutron scattering (HP-SANS) as a non-destructive method for time-resolved studies. Performing a similar screening of ovalbumin intermolecular interactions across applied pressures and ionic strengths reveals that net attractive interactions are significantly enhanced with increased pressure holding time. Pressure-induced effects are also shown not to be fully reversible in the presence of salt, and slow aggregation processes emerge more than 24 h after depressurization. Interaction data from long pressure incubations are then used to predict the protein relative viscosity. We use a combination of conventional viscometry and HP diffusing wave spectroscopy (HP-DWS) microrheology to demonstrate agreement between predicted and experimental viscosity data, providing a route to building predictive models by correlating multiple data sets together from distinct characterization approaches. ☐ Another novel contribution of the research in this dissertation is the first demonstration of in situ HP rheology for studying protein sol-gel behavior. HP-DWS is performed with in situ temperature control to measure the effects of HP on a thermoreversible protein sol-gel transition. One major contribution of this work is clear evidence that pressure and temperature induce orthogonal gelation mechanisms, and the rheological behavior of a pressure-induced gel varies significantly from that of a preset thermal gel under HP. We present a pressure-temperature phase diagram, from which the structural and mechanical properties of a gel can be potentially tuned using stepwise variations in pressure and temperature. The work presented here significantly advances current HP characterization capabilities by developing a new analytical tool for HP rheology of protein-based complex fluids. We additionally present a proposed design for simultaneous HP-SANS-DWS, which would enable optimized screening of protein formulation structure and rheology with in situ pressure and temperature control. ☐ We further demonstrate the irreversible effects of HP on salted-out ovalbumin dense phases using ex situ static light scattering (SLS) and SAXS. Gel microparticles formed at moderate salt concentrations and dense core-shell protein particles formed beyond a high-salt phase transition boundary both dissociate during pressure treatment, allowing for repacking into more tightly arranged structures that persist after depressurization. In contrast, gel microparticles near the phase transition line exhibit pressure-induced phase separation. Significantly, the gel particle network is replaced by dense core-shell structures, while the constituent gel clusters persist. This result implies a gradually reduced favorability of the gel phase with pressurization, allowing crystallization to dominate with a sufficiently high applied pressure, and confirms the hypothesis that competition between gelation and crystallization dictates the dominant phase behavior. ☐ The research presented in this dissertation makes significant contributions to the mechanistic understanding of protein behavior under high pressure and begins to correlate data across multiple characterization approaches into structure-property relationships. By probing HP behavior simultaneously with other formulation and process parameters, the mechanisms through which each parameter influences structure, rheology, and phase behavior can be determined and decoupled. The results of the research in this dissertation have significant implications for property control during protein formulation processing, as material properties can be tuned through a carefully designed series of process steps.University of Delaware, Department of Chemical and Biomolecular EngineeringPh.D
Developing an alternative medium for in-space biomanufacturing
No full textThis article was originally published in Nature Communications. The version of record is available at: https://doi.org/10.1038/s41467-025-56088-2.
© 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/.In-space biomanufacturing provides a sustainable solution to facilitate long-term, self-sufficient human habitation in extraterrestrial environments. However, its dependence on Earth-supplied feedstocks renders in-space biomanufacturing economically nonviable. Here, we develop a process termed alternative feedstock-driven in-situ biomanufacturing (AF-ISM) to alleviate dependence on Earth-based resupply of feedstocks. Specifically, we investigate three alternative feedstocks (AF)—Martian and Lunar regolith, post-consumer polyethylene terephthalate, and fecal waste—to develop an alternative medium for lycopene production using Rhodococcus jostii PET strain S6 (RPET S6). Our results show that RPET S6 could directly utilize regolith simulant particles as mineral replacements, while the addition of anaerobically pretreated fecal waste synergistically supported its cell growth. Additionally, lycopene production using AF under microgravity conditions achieved levels comparable to those on Earth. Furthermore, an economic analysis shows significant lycopene production cost reductions using AF-ISM versus conventional methods. Overall, this work highlights the viability of AF-ISM for in-space biomanufacturing.This work was funded by the Defense Advanced Research Projects Agency B-SURE program (HR001122S0010) and (HR0011259287). The views, opinions, and/or findings expressed in this study should not be interpreted as representing the official views or policies of the Department of Defense or the U.S. Government
