bluuebunny/crossref_metadata_2025_split huggingface dataset:
Time series of phytoplankton net primary production reveals intense interannual variability and size‐dependent chlorophyll‐specific productivity on a continental shelf
Authors: Fontaine Diana N. , Marrec Pierre , Menden‐Deuer Susanne , Sosik Heidi M. , Rynearson Tatiana A. 
Published: December 2024

AbstractPhytoplankton community size structure influences the production and fate of organic carbon in marine food webs and can undergo strong seasonal shifts in temperate regions. As part of the Northeast US Shelf (NES) Long‐Term Ecological Research program, we measured net primary production (NPP) rates and chlorophyll a (Chl a) concentrations in three phytoplankton size classes (< 5, 5–20, and > 20 μm) during winter and summer for 3 yr along a coastal‐to‐offshore transect. Mean depth‐integrated NPP was 37% higher in summer than winter, with limited cross‐shelf differences because of significant interannual variability. When averaged across the shelf, depth‐integrated NPP was dominated by the > 20 μm size class in winter and generated equally by the three size fractions in summer because of substantial contributions from cells > 20 μm at the Chl a maximum depth. Furthermore, the relationship between Chl a and NPP, in terms of relative contributions, varied by size class. Variations in this relationship have implications for models of primary productivity on the NES and beyond. In comparison to historical NPP data, we identified equivalent levels of winter NPP but observed a 25% decrease in summer NPP, suggesting a potential reduction in the seasonality of NPP on the NES. Together, our results highlight seasonal shifts in NPP rates of different phytoplankton size classes, with implications for food web structure and export production. These data emphasize the importance of quantifying size‐fractionated NPP over time to constrain its variability and better predict the fate of organic carbon in coastal systems under environmental change.
Effect of LaF3 on the Properties of Pb‐Free Cu‐Based Self‐Lubricating Composites
Authors: Liu Cong , Yin Yanguo , Li Rongrong , Wang Haoping , Li Liang 
Published: December 2024

ABSTRACTA strategy involving the use the rare‐earth compound LaF3 with good lubrication and stability properties as a filler in the preparation of Cu‐based composites was proposed to solve the problem of poor wear resistance in Pb‐free Cu‐Bi materials. The influence and regulatory mechanism of LaF3 content on the mechanical and tribological properties of these composites were studied. The results indicate that LaF3 has a good refining effect on Cu alloy grains, and LaF3 and Bi are distributed in a network along the grain boundaries of the Cu alloy in the material. As the LaF3 content increases, the mechanical properties and friction coefficient of the composite gradually decrease, and the wear rate first declines and then increases. The wear resistance of Cu‐Bi composite containing LaF3 mainly depends on the mechanical support provided by the matrix. When the LaF3 content is higher than 6%, the composite strength is extremely low, and the increase in lubricant content at the friction interface does not play a decisive role in the material wear behaviour. The material wear rate increases with the increase in LaF3 content. Therefore, using 6% LaF3 is recommended to improve the wear resistance of the material and maintain a balance among its mechanical properties, antifriction and wear resistance.
Rapid and Versatile Functionalization of Poly‐Ethylene Imine via Dynamic Aminal Formation
Authors: Shen Peidong , Pollard Brett , Ueland Maiken , Lawes Douglas , Connal Luke A 
Published: December 2024

AbstractThe study of dynamic covalent chemistry (DCC) is growing rapidly in polymer chemistry. The dynamic covalent chemistry of polyaminals formed by the reaction of linear polyethyleneimine (L‐PEI) with various functional aldehydes is explored. The study demonstrates the pH‐dependent kinetics of polyaminal formation and the versatility of polyaminals in controlling the release of aldehydes under ambient conditions. Additionally, the controlled temperature‐induced release of aldehydes and the dynamic shuffling behavior of aminals in polymer systems are investigated, emphasizing the potential for dynamic, covalently bonded polymers through dynamic aminal chemistry. The research showed the dynamic covalent aminal exchange for creating a range of new polymer materials.
Extracellular Matrix‐Inspired Antibacterial Fibrous Hydrogels Containing Polyhexamethylene Biguanide and Gd3+
Authors: Chen Siyuan , Xi Jingyun , Xu Yuanyuan , Zhang Yuxin , Du Wenli , Meng Xinyue , Zhang Jieyu , Hu Xuefeng , Wang Yunbing 
Published: December 2024

AbstractTraditional bulk hydrogels containing antibiotics or metal ions often fall short in effectively treating wound infections due to mechanical limitations, bacterial resistance, and potential cytotoxicity. To address these challenges, an extracellular matrix (ECM)‐inspired antibacterial fibrous hydrogel featuring an anisotropic topological structure is developed that closely mimics the natural ECM environment. A novel antibacterial agent, PHMB‐VAN‐Gd (PVG), is synthesized by reacting polyhexamethylene biguanide (PHMB) with O‐Vanillin (VAN) to form the Schiff base ligand PHMB‐VAN (PV), followed by coordination with gadolinium ions (Gd3⁺). Employing silk fibroin (SF) as the matrix, the PVG complex is incorporated into fibrous hydrogels through electrospinning, generating structures that replicate the fibrous architecture of the ECM. The resulting SF‐PVG fibrous hydrogels exhibited robust antibacterial activity, effectively inhibiting bacterial growth and biofilm formation. Furthermore, the aligned fiber orientation and substantial mechanical strength of these hydrogels facilitated cellular functions, promoting cell attachment and proliferation. This study underscores the significant potential of SF‐PVG hydrogels for wound infection treatment.
Multicolor Mechanochromic Polymer Blends That Can Distinguish between Tensile–Stress States
Authors: Ishizuki Kuniaki , Takahashi Akira , Otsuka Hideyuki 
Published: December 2024

AbstractMechanochromic polymers can be used to visualize mechanical stimuli applied to materials. However, many of these polymers exhibit single‐color mechanochromism, i.e., the polymer changes from its original color to another, thus potentially limiting the range of applications. Here, a versatile and readily accessible strategy for creating multicolor mechanochromic polymer blends that can detect whether a material is currently under stress or has already experienced stress is presented. The polymer blends are prepared by blending a segmented polyurethane and a polycaprolactone, each embedded with a radical‐type mechanochromophore. These polymers appear either blue, pink, or green by stretching depending on the mechanochromophore employed. The introduction of different mechanochromophores into each of the segmented polyurethane and polycaprolactone polymers with different chain mobilities and the subsequent blending of these polymers affords a mechanochromic polymer blend that can be used to visually distinguish via a color change whether it is experiencing stress or has recently experienced stress. The colors observed under stress and after stress can be tuned as easily as mixing paint based on the combination of the mechanochromophores (“rainbow mechanochromism”). The strategy developed in this study can be expected to significantly advance the research of mechanochromic polymer materials.
Long COVID across SARS‐CoV‐2 variants: Clinical features, pathogenesis, and future directions
Authors: Lok Laurence Si Chong , Sarkar Shuvam , Lam Calista Chi In , Law Chak Fun , Chau Sin Teng , Leung Chun Yip Thomas , Cheang Wai Hin , Li Ting , Monteiro Olivia , Baptista‐Hon Daniel Tomas 
Published: December 2024

AbstractLong coronavirus disease (COVID) is characterized by persistent symptoms following severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection and has emerged as a significant health concern. As SARS‐CoV‐2 evolved from the wild‐type strain to the Alpha, Beta, Delta, and Omicron variants, there may be a variant‐specific influence on long COVID akin to the acute disease. This review aims to summarize our current knowledge of variant‐specific influences in long COVID incidence, symptom profile as well as mechanisms of pathogenesis. We highlight that long COVID incidence may be lower with the Omicron variants. The symptom profile of long COVID may also show some dependence on the different variants, with a reduction in cardiopulmonary symptoms with more recent SARS‐CoV‐2 variants. This heterogeneity of long COVID may also be related to the variant‐specific differences in affecting the immune system, viral persistence, and autoimmunity. However, emerging data also suggest that vaccinations may play a big role in shaping the presentation of long COVID. We also highlight ongoing work on long COVID incidence and symptom profiles in populations infected only by the Omicron variants. This will be beneficial toward more useful disease definitions and the development of effective diagnostic and therapeutic strategies.
Physical Activity as a Buffer in the Association Between Perceived Ethnic‐Racial Discrimination and Latinx Adolescent Mental Health
Authors: Zhang Yuan , Halgunseth Linda C. 
Published: December 2024

ABSTRACTLatinx adolescents, members of the largest historically minoritized population in the United States (US), experience pervasive ethnic‐racial discrimination, adding extra challenges to this pivotal developmental stage which is marked by significant physical, cognitive, and psychosocial changes. Exposure to ethnic‐racial discrimination is closely connected to their mental health. Physical activity has numerous psychophysiological health benefits, making it a potential yet understudied protective mechanism against the adverse impacts of perceived discrimination. By utilizing data from the Adolescent Brain Cognitive Development (ABCD) Study, the current study examined the buffering effect of physical activity in the association between perceived ethnic‐racial discrimination and mental health in a national sample of Latinx adolescents (N = 1392; Mage = 11.92 SD = 0.66). Findings revealed that longer periods of moderate‐to‐vigorous physical activity exhibited a weaker positive association between perceived ethnic‐racial discrimination and internalizing problems compared to peers who engaged in shorter periods of moderate‐to‐vigorous physical activity, indicating a protective role of physical activity for Latinx adolescents experiencing ethnic‐racial discrimination. This study highlights the importance of promoting moderate‐to‐vigorous physical activity to support resilience and mental health in Latinx youth facing ethnic‐racial discrimination.
Angle‐Adjusted Transverse Thoracodorsal Artery Perforator Flap in Lower Extremity Reconstruction: A Case Series of 63 Patients
Authors: Park Jin‐Woo , Park Bo Young 
Published: December 2024

ABSTRACTBackgroundThe thoracodorsal artery perforator (TDAP) flap is a viable option for reconstructing various soft tissue defects. Despite its numerous benefits, including reduced donor site morbidity, the TDAP flap has not gained popularity because of its anatomical variations and technical challenges. Herein, we aimed to introduce the application of the angle‐adjusted transverse TDAP flap in lower extremity reconstruction and provide novel perspectives, with emphasis of outcomes.MethodsWe retrospectively analyzed data from patients who underwent lower extremity reconstruction using a novel, modified transverse‐TDAP flap at a single center between 2015 and 2019. This modification introduced a more transverse pattern with an innovative angle adjustment of approximately 30°–60°, specifically designed to optimize coverage and adaptability to various defects and aimed to prevent irritation at the posterior aspect of the scar, which could otherwise lead to pain during rehabilitation—addressing a common challenge in traditional TDAP flap designs. We conducted a comprehensive assessment of the TDAP flap, including patient characteristics, surgical details, long‐term outcomes, functional evaluation of donor site using the American Shoulder and Elbow Surgeons (ASES) Score, and postoperative complications.ResultsSixty‐three consecutive patients who underwent TDAP free flap reconstruction were included. Mean follow‐up duration was 54.3 months; most common etiology was trauma (25 cases; 39.7%), followed by diabetes (16 cases; 28.6%). Twenty‐six cases (41.3%) involved lesions in the foot, and 11 (17.5%) involved lesions in the distal tibia. Complications included total flap loss in five patients and donor site complications in one patient. As assessed using the ASES, the average functional score of the donor site was 97.8 points.ConclusionsThe modified transverse‐TDAP flap provides favorable outcomes with minimal donor site morbidity, making it a viable alternative in clinical practice. Its design ensures effective coverage with reduced complications, establishing it as a reliable choice for lower extremity reconstruction.
WNT2 blockade augments antitumor immunity by attenuating myeloid‐derived suppressor cells in colorectal cancer
Authors: Cui Cheng , Zhang Tian‐Tian , Lin Qian , Huang Tu‐Xiong , Rao En‐Yu , Du Ji‐Hui , Fu Li 
Published: December 2024

AbstractColorectal cancer (CRC) ranks as one of the most common malignancies worldwide. Myeloid‐derived suppressor cells (MDSCs) represent an immunosuppressive heterogeneous population of immature monocytes and granulocytes constituting a major obstacle for CRC therapy. Previous studies demonstrated that WNT2 is enriched in tumor microenvironment (TME), promoting CRC progression. However, the role of WNT2 in regulating MDSCs to facilitate CRC progression remains largely unexplored. Our analysis of The Cancer Genome Atlas (TCGA) database and blood samples from 50 primary and recurrent CRC patients revealed a positive correlation between WNT2 expression and MDSCs abundance. Treatment with recombinant WNT2 protein significantly enhanced the accumulation and immunosuppressive function of MDSCs in vitro. Conversely, anti‐WNT2 monoclonal antibody remarkably reduced the percentage and functional activity of MDSCs in CRC tumor‐bearing mice. Mechanistic analyses further demonstrated that WNT2 mediates MDSCs activities through the p38 MAPK/Akt pathway. Collectively, our findings not only highlight the pivotal role of WNT2 in CRC progression by enhancing MDSCs activities within the TME, but also provide evidence that WNT2 levels and MDSCs abundance in peripheral blood could serve as predictive biomarkers for early diagnosis and prognosis of CRC patients.
On the Use of Strong Proton Donors as a Tool for Overcoming Line Broadening in NMR: A Comment
Authors: Charisiadis Pantelis , Venianakis Themistoklis , Papaemmanouil Christina D. , Primikyri Alexandra , Tzakos Andreas G. , Siskos Michael G. , Gerothanassis Ioannis P. 
Published: December 2024

ABSTRACTOvercoming line broadening of labile protons and achieving high‐resolution NMR spectra is crucial for the structural and conformational analysis of organic molecules. Recently, Ma et al. (Magn. Reson. Chem. 2024, 62, 198–207) demonstrated the effectiveness of 2,2,2‐trifluoroacetic acid (TFA) in sharpening NMR signals for nitrogen‐containing compounds which exhibit prototropic tautomerization or conformational isomerism using high molar ratio of [acids]/[solute] ~ 5 to 200. In this commentary, we provide an overview of earlier publications and highlight the extensive applications of TFA in enhancing NMR resolution across a variety of organic functional groups, with the use of very small ratios of [acids]/[solute] ~ 10−3 to 10−2. The prospects for the unequivocal structure analysis using labile protons as the starting point will be analyzed.
Grafting Well‐Defined Synthetic Polymers to Chitosan Nanocrystals via Nitroxide‐Mediated Polymerization
Authors: Ramirez‐Foyo Carlos Antonio , García‐Valdez Omar , Leung Alfred C. W. , Lam Edmond , Champagne Pascale , Cunningham Michael F. 
Published: December 2024

AbstractChitosan nanocrystals (ChsNCs) are a renewable resource attracting research interest due to their outstanding physical, chemical, and mechanical properties. ChsNCs exhibit promising potential applications as reinforcing materials in polymer‐based nanocomposites. However, the hydrophilic surface of ChsNCs leads to poor dispersibility in hydrophobic polymer matrices, hindering these potential applications. In this work, the first graft modification of ChsNCs using nitroxide‐mediated polymerization (NMP) is reported. ChsNCs are initially functionalized with glycidyl methacrylate to provide a reactive surface group that enables the polymer‐graft modification. Polystyrene and poly (methyl methacrylate) with well‐defined molecular weight polymers are first synthesized via NMP, and the polymers are then “grafted to” the ChsNCs surface, yielding polymer‐graft modified ChsNCs.
Acceleration of Simultaneous Multislice Magnetic Resonance Fingerprinting With Spatiotemporal Convolutional Neural Network
Authors: Lu Lan , Liu Yilin , Zhou Amy , Yap Pew‐Thian , Chen Yong 
Published: December 2024

ABSTRACTMagnetic Resonance Fingerprinting (MRF) can be accelerated with simultaneous multislice (SMS) imaging for joint T1 and T2 quantification. However, the high inter‐slice and in‐plane acceleration in SMS‐MRF causes severe aliasing artifacts, limiting the multiband (MB) factors to typically 2 or 3. Deep learning has demonstrated superior performance compared to the conventional dictionary matching approach for single‐slice MRF, but its effectiveness in SMS‐MRF remains unexplored. In this paper, we introduced a new deep learning approach with decoupled spatiotemporal feature learning for SMS‐MRF to achieve high MB factors for accurate and volumetric T1 and T2 quantification in neuroimaging. The proposed method leverages information from both spatial and temporal domains to mitigate the significant aliasing in SMS‐MRF. Neural networks, trained using either acquired SMS‐MRF data or simulated data generated from single‐slice MRF acquisitions, were evaluated. The performance was further compared with both dictionary matching and a deep learning approach based on residual channel attention U‐Net. Experimental results demonstrated that the proposed method, trained with acquired SMS‐MRF data, achieves the best performance in brain T1 and T2 quantification, outperforming dictionary matching and residual channel attention U‐Net. With a MB factor of 4, rapid T1 and T2 mapping was achieved with 1.5 s per slice for quantitative brain imaging.
Compressive‐Sensing‐Assisted Mixed Integer Optimization for Dynamical System Discovery With Highly Noisy Data
Authors: Shi Tony , Ma Mason , Tran Hoang , Zhang Guannan 
Published: December 2024

ABSTRACTThe identification of governing equations for dynamical systems is an everlasting challenge for the fundamental research in science and engineering. Machine learning has exhibited great success in learn and predicting dynamical systems from data. However, the fundamental challenges still exist: discovering the exact governing equations from highly noisy data. In the present work, we propose a compressive sensing‐assisted mixed integer optimization (CS‐MIO) method to make a step forward from a modern discrete optimization lens. In particular, we first formulate the problem into a mixed integer optimization model. The discrete optimization nature of the model leads to exact variable selection by means of cardinality constraint, and thereby powerful capability of exact discovery of governing equations from noisy data. Such capability is further enhanced by incorporating compressive sensing and regularization techniques for highly noisy data and high‐dimensional problems. The case studies on classical dynamical systems have shown that CS‐MIO can discover the exact governing equations from large‐noise data, with up to two orders of magnitude larger noise compared with state‐of‐the‐art methods. We also show its effectiveness for high‐dimensional dynamical system identification through the chaotic Lorenz 96 system.
Responses to Scandals in Nonprofit Organizations: A Moral Reasoning Model of Volunteer Support
Authors: Jedicke Eva Maria , Nolte Isabella M. , Lindenmeier Jörg 
Published: December 2024

ABSTRACTWhile research on donor reactions to nonprofit scandals has increased recently, the reaction of volunteers remains understudied. Therefore, this study addresses the impact of nonprofit scandals on volunteer behavior. Drawing on the moral reasoning framework, this research examines how the moral reasoning strategies of moral rationalization, moral decoupling, and moral coupling affect volunteers' responses to nonprofit scandals. This study considers volunteers' time and cash donation behavior as response variables. Furthermore, our model integrates moral intensity and cognitive dissonance as drivers of volunteers' support behavior. The empirical study is based on cross‐sectional data and uses a structural equation approach for data analysis. This study provides insights into the dynamics of volunteer behavior in situations where the behavior of nonprofit organizations can be classified as unethical.
A Scalable Convex Min–Max Optimization Algorithm for Robust Control of Polytopic Positive Systems
Authors: Babazadeh Maryam , Akbarisisi Sanaz 
Published: December 2024

ABSTRACTIn this paper, we investigate the robust control of a class of bilinear positive systems. The main objective is to minimize the norm of the controlled system while dealing with polytopic uncertainties. In contrast to traditional Lyapunov‐based robust control problems with polytopic uncertainties, we establish that minimizing the objective function over the vertices of the polytopic set, rather than considering its infinite elements, is adequate for achieving the globally optimal solution. Following this, we present a customized algorithm that relies on partial cutting plane to address the min–max problem. The introduced robust control strategy exhibits global convergence to the optimal solution and demonstrates scalability with the number of states and the number of vertices in the uncertain family. Simulation results validate the effectiveness of the proposed strategy in handling uncertainties.