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Artificial kink defects enable high-efficiency degradation of nanocellulose via mechanochemical activation
No full textHigh-efficiency degradation and conversion of cellulosic biomass into biofuels and bio-based chemicals are critical to human society for sustainable development. Long-term challenges in deciphering how mechanical external force activates nanocellulose hydrolysis at the molecular level have hindered the wider application of mechanochemistry in high-efficiency degradation technologies. Here, combining multiscale modeling and in situ experimental characterization, we revealed the mechanochemistry hidden in the mechanically activated nanocellulose degradation behaviors, that artificial kink defects enable hydrolysis acceleration. The localized plastic deformation and nonlinear molecular geometry at kink defects drive hydrolysis processes toward the lower-barrier reaction pathway and facilitate hydrolysis accessibility. The proposed two-step mechanochemical hydrolysis strategy, introducing more artificial kink defects and preferential reaction sites via mechanical pretreatment, realizes substantial enhancement of hydrolysis efficiency. This study provides a framework for anticipating how mechanical external force, microstructure defects, and molecular geometric mutation contribute to the mechanochemical degradation of cellulosic biomass with more sustainability and bioeconomy
Caveolin-1/PPARα axis suppresses T follicular helper cell response in primary Sjögren disease
Get PDFT follicular helper (Tfh) cells play a central role in humoral autoimmunity, including primary Sjögren disease (SjD). However, targeting Tfh cells in clinical management is challenging. Previous studies suggest that inducible T cell co-stimulator (ICOS) directs Tfh cell motility in engaging bystander B cells and promoting plasma cell differentiation. Herein, we took advantage of the mouse model of experimental Sjögren syndrome (ESS) and identified an unappreciated role of caveolin-1 (Cav-1) in suppressing ICOS expression in Tfh cells and SjD pathogenesis. Peroxisome proliferator-activated receptor alpha (PPARα), a transcription factor downstream of Cav-1, rapidly repressed Icos transcription upon Tfh polarization, independent of lipid metabolism. Both Cav-1 and PPARα were decreased in CD4+ T cells from patients with SjD and ESS mice. Notably, the pharmaceutical agonist of PPARα suppressed human and murine Tfh cell responses both in vitro and in vivo and effectively ameliorated the disease pathology of ESS mice with chronic inflammation.published_or_final_versio
Demonstration of Al<i>X</i>Ga1-<i>X</i>N Solar-Blind UV Phototransistor With Double Heterostructures and Winding Gate
No full textWe have demonstrated a solar-blind ultraviolet (UV) phototransistor (PT) equipped with AlyGa 1−y N/AlxGa 1−x N/AlzGa 1−z N double heterostructures and winding gate configuration. There exists a 2-D electron gas (2DEG) at Al 0.55 Ga 0.45 N/Al 0.4 Ga 0.6 N heterointerface, due to the intrinsic polarization effect of AlxGa 1−x N. The Ni/Au metal stacks are deposited between two-sided interdigital Ohmic electrodes to form a Schottky gate. The gate can act as a switch to close or open the conduction channel between source and drain by the regulation of the 2DEG density. Thus, when given a specific negative gate voltage, the fabricated PT exhibits a photocurrent-to-dark-current ratio (PDCR) of 2.24×103 and a high responsivity of 1.86×103 A/W under 280 nm UV illumination at Vds=2 V, a high specific detectivity of 5.84×1014 Jones included, implying outstanding ability to detect solar-blind UV. Besides, to grasp the underlying mechanism of gate control and double heterostructures, comprehensive 2-D device simulations have performed, revealing that the variation trends of energy band and electron concentration are affected by the applied negative gate bias and incident light.</p
Competitive insurance pricing strategies for multiple lines of business: a game-theoretic approach
No full textThis paper explores an insurance market with insurers competing in multiple lines of business over a finite time horizon. They set premiums for single lines of business, whereas in a multi-policy contract, a discount is applied to the total sum of the single premiums. To illustrate the combinatorial components of the weighted average market premium, Young tableaux are used. We use the collective risk model to define insurers' aggregate loss, with claim amounts independent of distinct lines of business but dependent on the state of the environment. Our dynamic insurance game falls into the category of multi-stage games with observed actions. In this framework, we characterize the open-loop and closed-loop equilibrium premium profiles
Coping with peer suicidality, help-seeking intentions, and suicidal attitudes among Asian adolescents: a mixed-methods study in Hong Kong
No full textBackground: Adaptive responses to peer suicidality and the involvement of professional help are crucial for adolescent suicide prevention and may be influenced by suicidal attitudes. This study aimed to explore Hong Kong adolescents' responses to and help-seeking intentions for suicidal peers and to examine the influence of suicidal attitudes. Method: This study used an exploratory sequential mixed-methods approach targeting Hong Kong adolescents aged 15–19 between September 2018 and October 2019. Adolescents' reactions to peer suicidality, suicidal attitudes, and willingness to help were examined through six focus groups and 12 individual interviews (N = 40). A cross-sectional survey (N = 1676) was subsequently conducted to investigate the prevalence of different responses to peer suicidality, help-seeking intentions, differences by background characteristics, and the impacts of suicidal attitudes. Results: Qualitative findings revealed three major themes: attitudes toward suicide, reactions to peer distress and suicidality, and willingness to help suicidal individuals. Most survey respondents reported actively responding and seeking informal help, but not professional support. Differences were observed based on sex, academic performance, and self-suicidality. Notably, a stigmatizing attitude was positively associated with both response types and informal help-seeking intentions. The belief that suicide is unpreventable was positively associated with passive responses but negatively associated with active responses and informal help-seeking intentions. Conclusions: Our findings highlight variability in adolescents' responses to peer suicidality and help-seeking intentions, underscoring the need for attitude-tailored courses and more systematic, action-based gatekeeper training. Recommendations are provided to enhance the effectiveness of mental health first aid programs through public education, school interventions, and media campaigns
Shifting sands to sustainable soils: Spatial dynamics of soil water and salinity in a desert oasis ecotone
No full textUnderstanding the spatiotemporal patterns of soil moisture and salinity dynamics and their governing factors is essential for predicting salinization risks and developing mitigation strategies in arid agricultural landscapes. This study examined the vertical distribution (0–3 m) of soil water content (SWC), electrical conductivity (EC), and pH, and identified their dominant controls across bare sand dunes, nabkha dunes, and croplands of varying cultivation durations (2–5, 12–15, 25–30, and 40–50 years) in a desert–oasis ecotone of northwestern China. The results showed that SWC, EC, and pH generally increased with soil depth and were best described by quadratic or power functions. Bare sand dunes had the lowest values of all three parameters, while EC and pH peaked in nabkha dunes (188.20–636.83 μS·cm-¹ and 7.88–8.43, respectively), particularly those near the water area, where the early-stage cultivation may be more challenging. Conversion to cropland reduced surface (0–0.4 m) EC and pH by 7.3–34.7 % and 3.9–7.2 %, respectively, after 40–50 years of cultivation, in contrast, subsurface soil layers (0.4–3 m) exhibited stable EC and pH levels after long-term irrigation, with no significant changes between 25–30 and 40–50 years of cultivation (P > 0.05). However, subsurface salinity (0.4–1 m) in newly reclaimed croplands (2–5 years) tended to be higher than that in both nabkha dunes and older croplands, suggesting a potential risk of salinization in the new croplands, which require optimized irrigation. Soil texture was the dominant factor controlling SWC, while cultivation years primarily explained the variation in EC and pH. These findings reveal critical spatiotemporal dynamics in soil water-salt following land use change and offer guidance for optimizing irrigation practices to prevent secondary salinization in arid regions.</p
Viscous fingering instability in one-end-lifted Hele-Shaw cells for producing three-dimensional hierarchical structures
No full textHypothesis: The focal research on viscous fingering (VF) instabilities has primarily concentrated on alleviating and suppressing this phenomenon, but the potential to enhance and leverage them for developing practical applications remains inadequately explored. VF occurs when a less viscous fluid displaces a higher viscous fluid, governed by fluid dynamics and resulting in finger-like patterns at their interface in a facile and gentle way, yet sensitive to initial and boundary conditions, such as fluid type and cell thickness, giving rise to many bifurcating structures. Experiments: Leveraging Hele-Shaw cells (HSCs) with changing thicknesses that induced varying boundary conditions, we systematically investigated the characteristics of VF under these conditions and developed applications based on our findings. Findings: We introduce VF in one-end-lifted HSCs to enhance VF rather than suppression to achieve satisfactory tunability of finger size and harness it to explore application. It enables the moldless, facile, scalable, and cost-effective fabrication of diverse hierarchical structures derived from branched patterns composed of numerous dense fingers with progressively decreasing sizes. With this phenomenon, the finger width scales inversely with the capillary number raised to the power in a range between −0.53 to −1.22, depending on the varying boundary conditions. By capitalizing on the hierarchy and specific distribution ridge of the fingering patterns, the fabricated fractal structures exhibit physically nonclonable characteristics, offering promising applications in anti-counterfeiting
Autonomous Tomato Harvesting With Top–Down Fusion Network for Limited Data
No full textUsing robots for tomato truss harvesting represents a promising approach to agricultural production. However, incomplete acquisition of perception information and clumsy operations often results in low harvest success rates or crop damage. To addressthis issue, we designed a new method for tomato truss perception, an autonomous harvesting method, and a novel circular rotary cutting end-effector. The robot performs object detection and keypoint detection on tomato trusses using the proposed top–down fusion network, making decisions on suitable targets for harvesting based on phenotyping and pose estimation. The designed end-effector moves gradually from the bottom up to wrap around the tomato truss, cutting the peduncle to complete the harvest. Experiments conducted in real-world scenarios for robotic perception and autonomous harvesting of tomato trusses show that the proposed method increases accuracy by up to 11.42% and 22.29% for complete and limited dataset conditions, compared to baseline models. Furthermore, we have implemented an automatic tomato harvesting system based on TDFNet, which reaches an average harvest success rate of 89.58% in the greenhouse
Automatic Segmentation and Molecular Subtype Classification of Breast Cancer Using an MRI-based Deep Learning Framework
No full textPurpose: To build a deep learning framework using contrast-enhanced MRI for lesion segmentation and automatic molecular subtype classification ibreast cancer. Materials and Methods: This retrospective multicenter study included patients with biopsy-proven invasive breast cancer between January 2015 and Janua2021. An automatic breast lesion segmentation model was developed using three-dimensional (3D) ResU-Net as the backbone, and its accuracy was evaluated in an internal and two external testing datasets using the Dice score. An ensemble model for classification of breast cancer into four moleculasubtypes (Ensemble ResNet) was then developed by combining both two-dimensional and 3D lesion features. The performance of Ensemble ResNet wevaluated in the three testing datasets using the area under the receiver operating characteristic curve (AUC). Results: A total of 687 female patients (mean age ± SD, 48.70 years ± 8.97) were included, with 289, 61, 73, and 264 patients included in the training, internal testing, and two external testing datasets, respectively. The proposed segmentation model achieved high accuracy in internal testing dataset 1, external testing dataset 2, and external testing dataset 3 (Dice scores: 0.86, 0.82, 0.85) and luminal A, luminal B, human epidermal growth factor receptor 2 (HER2)-enriched, and triple-negative breast cancer (TNBC) subtypes (Dice scores: 0.8571, 0.8323, 0.8199, 0.8481). Ensemble ResNet demonstrated high performance for the prediction of luminal A subtypes (AUC range, 0.74–0.84), luminal B subtypes (AUC range, 0.68–0.72), HER2-enriched sub-types (AUC range, 0.73–0.82), and TNBC (AUC range, 0.80–0.81) in the three testing datasets. Conclusion: The proposed novel deep learning framework based on MRI achieved high, robust performance in fully automatic classification of breast camolecular subtypes