Institutional Repository
The UDSpace Institutional Repository collects and disseminates research material from the University of Delaware.
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- Departments can use UDSpace to publish or distribute their working papers, technical reports, or other research material.
- UDSpace also includes all doctoral dissertations from winter 2014 forward, and all master's theses from fall 2009 forward.
To learn more about UDSpace, and how you can make your research openly accessible to the public, visit our UDSpace Policies website.
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Recent Submissions
Aldehyde Electrophilicity and Ring Strain Govern Xylose Acetalization Pathways for Biobased Chemical Production
(Chemistry-Sustainability-Energy-Materials, 2025-12-25) John Li, Zezhong; Patel, Deep M.; Sun, Songlan; Bourmaud, Claire L.; Chen, Tso-Hsuan; Vlachos, Dionisios G.; Luterbacher, Jeremy S.
Xylose acetalization has emerged as a potent tool to extract this sugar from lignocellulosic biomass and for creating new biobased chemicals and materials. This article elucidates a generalized reaction network for xylose acetalization and reveals the role of aldehyde electrophilicity and ring strain in intermediate formation. Aldehydes with strong electrophilicity stabilize xylose as both furanose- and pyranose-monoacetals, whereas weaker aldehydes favour xylofuranose acetalization due to the high ring strain in pyranose acetals. The energetically favoured furanose diacetals dominate the product distribution over extended reaction time regardless of aldehyde types and reaction pathways. Measurements of the xylose tautomer ratio in the reaction conditions highlighted the importance of xylose isomerization in forming furanose acetals. These mechanistic insights not only explain the evolution of reaction intermediates but also aid in identifying potential products for sustainable chemical synthesis.
Impact of COVID-19 on patellar tendon properties over the first year after infection
(Scientific Reports, 2026-01-07) de Jesus Ferreira. Leandro Gomes; da Silva Almeida, Isabella; Costa, Rochelle Rocha; Roriz, Gabrielle Vieira; Farinha, Rebeca Carvalho Moreira; Grävare Silbernagel, Karin; Geremia, Jeam Marcel; Quagliotti Durigan. João Luiz; Rita de Cássia Marqueti
This study aimed to examine the impact of infection severity and associated inactivity on patellar tendon health following COVID-19. Seventy participants were divided into three groups: moderate COVID-19 (n = 22), severe COVID-19 (n = 18), and control (n = 30). Four assessments were conducted over one-year for the COVID groups - between the 21st and 30th days (A21−30), 31 and 90 days (A31−90), 91 and 180 days (A91−180), and 181 and 360 days (A181−360) after the onset of symptoms for moderate or hospital discharge for severe. Maximal voluntary isometric knee extension contractions were performed, with simultaneous ultrasound imaging of patellar tendon length to calculate material and mechanical properties. Morphological properties (length and cross-sectional area) were obtained at rest. During one year, the severe group consistently had lower state of load on tendon (p < 0.002) and stress (p < 0.001) compared to the moderate and control groups, while strain in the first three months post-infection was comparable to the other groups (p > 0.256). A reduction in stiffness (p < 0.009) and Young’s modulus (p < 0.015) was observed during the same assessment period. Severe infection cases were associated with prolonged reductions in tendon load and stress. These findings suggest that systemic effects of infection and reduced activity levels may contribute to tendon adaptations.
Just-in-Time Adaptive Intervention to Promote Walking Behavior and Reduce Stationary Time in Physically Inactive Adults: Protocol for the Walking With JITAIs Study
(JMIR Research Protocols, 2026-01-07) Firkin, Cora J; Vemuri, Ajith; Rahman, Tanvir; Bodt, Barry; Orsega-Smith, Elizabeth; Decker, Keith; Dominick, Gregory M
Background: A Just-in-Time Adaptive Intervention (JITAI) recognizes the dynamic nature of individuals’ states and contexts, predicts support needs, and sends tailored support at more opportune, actionable times.
Objective: This paper outlines the application architecture and protocol for the pilot “Walking With Just-in-Time Adaptive Interventions” (WWJ) study, which uses a JITAI approach to improve walking behavior—duration, speed, and distance—and
reduce stationary time, defined as idle sitting or standing.
Methods: This study targets 20 adults who are physically inactive and leverages the Apple Watch to deliver fully automated tailored intervention notifications to “walk faster,” “walk longer,” or “stand up and move around” based on real-time data and
contextual factors, including time-of-day activity patterns, geographic locations (eg, home, work, park, and gymnasium), weather conditions (eg, precipitation, wind speed, and humidity), and receptiveness. The protocol involves a preintervention assessment
of demographics, behavior change constructs, anthropometrics, and resting vital signs; a 2-week observation period to establish walking behavior and stationary time baselines; a 2-week just-in-time learning period to evaluate receptiveness to untailored
prompts at all applicable times; the 2-week JITAI intervention phase; and a postintervention assessment. Feasibility will be evaluated through protocol fidelity, participant adherence, Apple Watch wear-time compliance, user burden, acceptability ratings,
and perceptions of benefits and preferences.
Results: The WWJ architecture development began in spring 2021 and concluded in fall 2022. Participant recruitment and enrollment began in fall 2022. A total of 18 participants were recruited. Upon completion of the analyses, the results of this study
are expected to be submitted for publication.
Conclusions: Distinctively, the WWJ just-in-time learning period aims to train the learner based on user receptiveness within contexts by sending interventions whenever a participant meets the predetermined thresholds regardless of the likelihood that the
user will be receptive to the notification to prune out non opportune or “nonactionable” times. This approach may allow for greater customization during the JITAI period.
Cross-scale 3-D thermohaline modeling via dual-residual swin transformer with multisource ocean observations
(International Journal of Digital Earth, 2025-12-30) Wang, An; Tang, Zhiwei; Huang, Zhanchao; Xia, Xiang-Gen; Su, Hua
Integrating multisource Earth observation data and reconstructing subsurface thermohaline structures from remote sensing at global and basin scales will provide a better understanding of oceans. However, previous methods relied on layer-by-layer modeling, which required separate reconstruction of subsurface temperature and salinity fields at different depths, resulting in many models, inefficiency, and weak vertical connections between thermohaline data at different depths. A fast deep neural network-based reconstruction can reduce models and enhance the overall consistency of thermohaline data, which is significant for the reconstruction of ocean environmental variables. This study proposes an improved Swin Transformer approach, i.e. SwinOcean3D, to perform one-shot reconstruction of three-dimensional (3-D) thermohaline structures (upper 1000 m) in different scales of Global (1° × 1°) and Indian Oceans (0.25° × 0.25°) by integrating multisource remote sensing and observation-based ocean products. SwinOcean3D combines the Swin Transformer, U-net, and dual-residual blocks to enhance the representation capability of the global scale, local detailed, and vertical features of ocean thermohaline structures. The significant advantages of SwinOcean3D in the reconstruction of multiscale 3-D thermohaline structures outperform other classical approaches. Furthermore, interpretability experiments suggest that SwinOcean3D can effectively capture the evolution of 3-D thermohaline structures from multisource observations.
Differences in Executive Functioning Performance and Cortical Activation Between Autistic and Non-Autistic Youth During an fNIRS Flanker Task: A Pilot Study
(Brain Sciences, 2025-12-31) Tsai, Jung-Mei; Corey, Jacob; Tsuzuki, Daisuke; Bhat, Anjana
Background/Objectives: Autism spectrum disorder is associated with executive functioning (EF) challenges, yet the neural correlates of EF challenges in autistic youth remain unclear. This study aimed to examine EF performance and cortical activation in autistic versus non-autistic youth, using functional near-infrared spectroscopy (fNIRS) during a modified Flanker task. Methods: Thirty age-matched (11.6 ± 0.8 years) autistic (N = 15) and non-autistic youth (N = 15) completed congruent and incongruent conditions of a modified Flanker task while cortical activation in prefrontal, parietal, and temporal regions was recorded using fNIRS. The Behavior Rating Inventory of Executive Function (BRIEF) was used to assess general EF impairments. Behavioral data (i.e., Flanker task mean reaction time/accuracy, and reaction time variability) and cortical activation were analyzed using ANCOVAs. Pearson correlations were used to determine the relationship between cortical activation, EF performance, and clinical measures. The significance level was set at p < 0.05, with FDR corrections for multiple comparisons. Results: While mean reaction time and accuracy were comparable across groups, autistic youth exhibited greater reaction time variability (autistic youth = 34.8 ± 10.36; controls = 26.4 ± 1.94, p = 0.02, Hedges’ g = 0.85) and higher BRIEF index scores compared to controls (ps < 0.001, Hedges’ gs > 1.3; e.g., Global Executive Composite Score for autistic youth = 71.3 ± 3.7; controls = 47.8 ± 2.4), indicative of delayed EF development. During the incongruent condition, compared to non-autistic controls, autistic youth showed lower left inferior parietal lobe (IPL) activation (Mean HbO2 in autistic youth = −0.02 ± 0.006 mmol.mm; controls = 0.01 ± 0.006 mmol.mm, ps < 0.001, Hedges’ g = 0.5) and a lack of left-lateralized activation (e.g., left vs. right STS activation, p < 0.001, Hedges’ g = 0.41 in the non-autistic youth). In the ASD group, lower activation in the left STS was associated with lower EF performance (r = −0.28, p = 0.007), whereas greater activation in various right-hemispheric ROIs was associated with better EF performance (r = −0.31 to −0.35, ps < 0.005), suggesting potential compensatory activation. Conclusions: The findings revealed ASD-specific differences in the neural correlates of EF performance and possible alternative compensatory activation patterns. These potential neural correlates of EF performance highlight the utility of fNIRS-based neural measures to better understand the neural bases of EF differences in autism. Study Registration: This study was approved by the Institutional Review Board (IRB) at the University of Delaware (Protocol #: 1947455) on 4 October 2022.