Single‐atom catalysts (SACs) attract extensive attention in the field of heterogeneous catalysis in recent years due to the maximum atom utilization and unique physical and chemical properties. The ...gas sensing is actually a heterogeneous catalysis process but the SACs are new to this area. Although SACs show huge potential in gas sensing, the SACs gas sensing area currently is still at the infancy stage. This work critically reviews the recent advances and current status of single‐atom gas sensing materials. General synthesis routes, characterization methods, and sensing performance indexes are introduced. At the end, the challenges and future prospects on SACs gas sensing are presented from the authors’ perspectives. This work is anticipated to provide insights and guideline for the chemical sensing community.
Gas sensors are widely used in many areas. Compared to the traditional sensing materials including semiconductors, nanomaterials, and 2D materials, the emerging single‐atom catalysts (SACs) show great potential owing to the maximum atom utilization and unique chemical and physical properties. This work timely summarizes the recent progress and provides future perspectives on the SACs sensing.
Innovation and entrepreneurship are essential for higher vocational students to escape low-end employment and are vital for vocational education to provide diverse products and services, fulfilling ...the people’s demand for a better life. This study builds on the theory of innovation and entrepreneurship education, integrating information technology to devise the “Four-Drive-One-Guide” model for vocational colleges. Utilizing Province A as a case study, a survey was conducted to gather data on the effectiveness of this education model, analyzed using ANOVA, Pearson’s correlation coefficient, and multiple linear regression. Furthermore, the operational efficiency of innovation and entrepreneurship education across 30 Chinese regions was assessed using the CCR model within the DEA framework. Findings reveal that the “Four-Drive-One-Guide” model significantly boosts students’ innovative and entrepreneurial capabilities, with an average rating of 4.06. The most influential factor in its effectiveness is students’ attitudes, with a coefficient of 0.238. Moreover, vocational colleges in the eastern region exhibit the highest comprehensive efficiency at 0.875. The study suggests that integrating industry teaching and optimizing the curriculum can further enhance students’ innovative and entrepreneurial thinking.
Prolonged exposure to negative stressors could be harmful if a subject cannot respond appropriately. Strategies evolved to respond to stress, including repetitive displacement behaviours, are ...important in maintaining behavioural homoeostasis. In rodents, self-grooming is a frequently observed repetitive behaviour believed to contribute to post-stress de-arousal with adaptive value. Here we identified a rat limbic di-synaptic circuit that regulates stress-induced self-grooming with positive affective valence. This circuit links hippocampal ventral subiculum to ventral lateral septum (LSv) and then lateral hypothalamus tuberal nucleus. Optogenetic activation of this circuit triggers delayed but robust excessive grooming with patterns closely resembling those evoked by emotional stress. Consistently, the neural activity of LSv reaches a peak before emotional stress-induced grooming while inhibition of this circuit significantly suppresses grooming triggered by emotional stress. Our results uncover a previously unknown limbic circuitry involved in regulating stress-induced self-grooming and pinpoint a critical role of LSv in this ethologically important behaviour.
Although previous studies have found that melatonin can promote seed germination, the mechanisms involved in perceiving and signaling melatonin remain poorly understood. In this study, it was found ...that melatonin was synthesized during cucumber seed germination with a peak in melatonin levels occurring 14 hr into germination. This is indicative of a correlation between melatonin synthesis and seed germination. Meanwhile, seeds pretreated with exogenous melatonin (1 μm) showed enhanced germination rates under 150 mm NaCl stress compared to water‐pretreated seeds under salinity stress. There are two apparent mechanisms by which melatonin alleviated salinity‐induced inhibition of seed germination. Exogenous melatonin decreased oxidative damage induced by NaCl stress by enhancing gene expression of antioxidants. Under NaCl stress, compared to untreated control, the activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) were significantly increased by approximately 1.3–5.0‐fold, with a concomitant 1.4–2.0‐fold increase of CsCu‐ZnSOD, CsFe‐ZnSOD, CsCAT, and CsPOD in melatonin‐pretreated seeds. Melatonin also alleviated salinity stress by affecting abscisic acid (ABA) and gibberellin acid (GA) biosynthesis and catabolism during seed germination. Compared to NaCl treatment, melatonin significantly up‐regulated ABA catabolism genes (e.g., CsCYP707A1 and CsCYP707A2, 3.5 and 105‐fold higher than NaCl treatment at 16 hr, respectively) and down‐regulated ABA biosynthesis genes (e.g., CsNECD2, 0.29‐fold of CK2 at 16 hr), resulting in a rapid decrease of ABA content during the early stage of germination. At the same time, melatonin positively up‐regulated GA biosynthesis genes (e.g., GA20ox and GA3ox, 2.3 and 3.9‐fold higher than NaCl treatment at 0 and 12 hr, respectively), contributing to a significant increase of GA (especially GA4) content. In this study, we provide new evidence suggesting that melatonin alleviates the inhibitory effects of NaCl stress on germination mainly by regulating the biosynthesis and catabolism of ABA and GA4.
The hierarchically core-shell BiOI@Zn/Ti hydrotalcite (LDH) composites with p-n heterostructure was successfully prepared by layer-by-layer self-assembly using a facile hydrothermal method, where the ...ZnTi-LDH nanoplatelets were coated on the BiOI core to form the flower-like BiOI@ZnTi-LDH microspheres. The morphology, microstructure, surface properties, photoelectric performances and visible-light response of the BiOI@ZnTi-LDH were also investigated in detail. Comparing to the single BiOI and ZnTi-LDH components, the p-n heterostructure BiOI@ZnTi-LDH indicated excellent enhanced photocatalytic activity for hexavalent chromium (Cr(VI)) reduction under visible-light irradiation (λ > 420 nm), which was imputed to the efficient combination of the unique 3D hierarchical core-shell structure and p-n heterojunction endowing the photogenerated electronhole pairs with efficient transfer and separation abilities. At the same time, In virtue of spectroscopy, Mott-Schottky and photoelectric techniques, the formation of p-n heterostructure and the charge transfer between BiOI and ZnTi-LDH were determined. So, this work provided a promising approach for the design and construction of smart 3D hierarchical core-shell materials in environmental treatment.
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•Hierarchical BiOI@ZnTi-LDH core-shell material with p-n heterostructure was prepared using a simple hydrothermal method.•ZnTi-LDH nanoplatelets were coated on the BiOI core to form the BiOI@ZnTi-LDH microspheres with unique 3D structure.•The enhanced photoreduction performances were to the formation of p-n heterojunction and unique 3D structure.
This brief presents a fractional coupled model of fractional-order wireless power transfer (FOWPT) system based on the fractional calculus. By applying coupled-mode theory (CMT), dynamic ...characteristics of fractional systems can be described clearly while avoiding complex circuit models. The theoretical simulation results indicate that the FOWPT system has better characteristics and greater design freedom. Furthermore, the fractional coupled model is in good agreement with the circuit model and experiment, which proves the correctness of the generalized fractional coupled mode equations. Therefore, the fractional coupled model provides a valuable tool for the further analysis of FOWPT systems and may be used in other fractional-order resonant circuits.
Nowadays, much effort focuses on research for the multireceiver wireless power transfer (WPT) system based on magnetic resonance. However, its output characteristics are significantly deteriorated by ...the variation of transfer spacing, loads, and cross-couplings, which exerts harmful effects on the performances of cascading bucks before loads if needed. Inspired by the work of a single-receiver WPT system based on the parity time symmetric model, in this article, the self-oscillating source is first applied to the multireceiver WPT system to tackle these drawbacks. Based on the coupled-mode theory, the proposed system's modeling is established and deduced to analyze its performance. The model analysis shows how the system can achieve zero-voltage switching simply via choosing the minimum dead time and leading time whose calculation method is provided. Meanwhile, a transmitting coil for a uniform magnetic field is designed to improve the free-positioning performance. The analysis is validated on a 36-W prototype, including the effects of the variation of transfer spacing, cross-couplings, and loads on the output characteristics, efficiency, and operating frequency. The proposed system is demonstrated to provide a much more robust power transfer than the conventional magnetic-resonant multireceiver WPT system, which helps extend the transfer distance and improve the system efficiency.
The potassium‐ion battery (PIB) has emerged as a promising alternative to lithium‐ion batteries. The major challenges confronted by PIB anodes lie in sluggish kinetics and poor cycling stability ...owing to the inherent large K+ size. Here, a hybrid of ball‐cactus‐like Bi nanospheres embedded in 3D N‐riched carbon nanonetworks (Bi NSs/NCNs) is designed and synthesized by electrospinning. As an anode, Bi NSs/NCNs exhibits an unprecedented rate (489.3 mAh g−1 at 50 A g−1) and long‐cycling performance (457.8 mAh g−1 at 10 A g−1 after 2000 cycles), outperforming all reported PIB anode materials. Such outstanding performance mainly originates from the stable solid‐electrolyte interface formed in the glyme‐based electrolyte and the unique interconnected porous nanostructure, both of which contribute to fast kinetics and high pseudocapacitive contributions upon cycling.
A hybrid of ball‐cactus‐like Bi nanospheres embedded in 3D N‐riched carbon nanonetworks (Bi NSs/NCNs) is designed and synthesized by electrospinning. As an anode, Bi NSs/NCNs exhibit unprecedented rate performance (489.3 mAh g−1 at 50 A g−1), outperforming all reported potassium‐ion battery anode materials.
Density functional theory calculations have been performed to probe the detailed mechanisms of Brønsted‐acid‐catalyzed ring‐opening reactions of donor‐acceptor cyclopropanes. The reaction model ...without consideration of the explicit solvation effect was characterized by a high activation free energy of 29.5 kcal/mol, while inclusion of the explicit solvation effect in calculations lowered the activation free energy to 20.5 kcal/mol, which demonstrated the cooperative role of HOTf and HFIP in facilitating the ring‐opening step. Additionally, we put forward two distinct reaction mechanisms, including the nucleophile‐induced mechanism and the protonation‐induced mechanism, for the ring‐opening step of donor‐acceptor cyclopropanes. Computational results revealed that modulation of the reaction conditions could result in the shift of the reaction mechanisms.
Brønsted‐acid‐catalyzed ring‐opening reactions of donor‐acceptor cyclopropanes were studied by density functional calculations. Two distinct reaction mechanisms, including the nucleophile‐induced mechanism and the protonation‐induced mechanism, were comparatively characterized. Inclusion of the explicit solvation model in calculations was confirmed to be crucial for obtaining reliable computational results.
Abstract
Beat-to-beat R-R intervals (RRI) and pulse arrival time (PAT) provide pivotal information to evaluate cardiac autonomic functions for predicting arrhythmias and cardiovascular morbidity. ...However, their relationship has not been clearly understood. In this study, we simultaneously recorded electrocardiograms and photoplethysmograms on 34 subjects in the natural state, and on 55 subjects under the cold stimulation. The RRI and the PAT were calculated and then analyzed using Pearson correlation coefficient. The results showed that the RRI and the PAT were strongly correlated (
r
= 0.562) and the RRI series were 2.18 ± 0.40 beats advanced to the PAT series. After smoothing, the RRI and the PAT were more correlated in the low frequency than in the high frequency. Furthermore, when involving RRI with the phase effect, the proposed PAT based model showed better performance for blood pressure estimation. We think these results are helpful to understand the underlying regulatory mechanisms of the two cardiovascular factors, and would provide useful suggestions for non-invasive cuffless blood pressure estimation.
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