The unstable triplet excited state is a core problem when developing self‐protective room temperature phosphorescence (RTP) in carbon dots (CDs). Here, fluorine and nitrogen codoped carbon dots ...(FNCDs) with long‐lived triplet excited states, emitting pH‐stabilized blue fluorescence and pH‐responsive green self‐protective RTP, are reported for the first time. The self‐protective RTP of FNCDs arises from n–π * electron transitions for CN/CN bonds with a small energy gap between singlet and triplet states at room temperature. Moreover, the interdot/intradot hydrogen bonds and steric protection of CF bonds reduce quenching of RTP by oxygen at room temperature. The RTP emission of FNCDs shows outstanding reversibility, while the blue fluorescence emission has good pH stability. Based on these FNCDs, a data encoding/reading strategy for advanced anticounterfeiting is proposed via time‐resolved luminescence imaging techniques, as well as steganography of complex patterns.
Fluorine and nitrogen co‐doped carbon dots (FNCDs) with long‐lived triplet excited states, emitting pH‐stabilized blue fluorescence and pH‐responsive green self‐protective room temperature phosphorescence (RTP) are reported. The self‐protective RTP of FNCDs arises from n–π* electron transitions for CN/CN bonds. And the interdot/intradot hydrogen bonds and steric protection of CF bonds can reduce quenching of RTP by oxygen at room temperature.
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The conjectured duality between color and kinematics has significantly advanced our understanding of both gauge and gravitational theories. However, constructing numerators that manifest ...the color-kinematics (CK) duality, even for the two-loop four-gluon amplitude in pure Yang-Mills, has been challenging. In this paper, we revisit this amplitude and show that the difficulty of applying CK duality can be overcome by introducing a simple deformation. Our approach distinguishes itself from previous studies by maximizing the use of off-shell CK duality while maintaining a compact ansatz. In particular, the deformation we introduce satisfies a subset of off-shell dual Jacobi relations. The resulting numerators are presented in
d
-dimensionally Lorentz invariant local form and are applicable to all helicities of external gluons. The solution we provide can be directly employed to construct the corresponding gravitational amplitude through double copy. Our findings suggest a novel and efficient strategy for constructing high-loop gauge and gravitational amplitudes using CK duality.
Peucedanum decursivum (Miq.) Maxim (P. decursivum) is a traditional Chinese medicinal plant with pharmacological effects such as anti-inflammatory and anti-tumor effects, the root of which is widely ...used as medicine. Determining the spatial distribution and pharmacological mechanisms of metabolites is necessary when studying the effective substances of medicinal plants. As a means of obtaining spatial distribution information of metabolites, mass spectrometry imaging has high sensitivity and allows for molecule visualization. In this study, matrix-assisted laser desorption mass spectrometry (MALDI-TOF-MSI) and network pharmacology were used for the first time to visually study the spatial distribution and anti-inflammatory mechanism of coumarins, which are metabolites of P. decursivum, to determine their tissue localization and mechanism of action. A total of 27 coumarins were identified by MALDI-TOF-MSI, which mainly concentrated in the cortex, periderm, and phloem of the root of P. decursivum. Network pharmacology studies have identified key targets for the anti-inflammatory effect of P. decursivum, such as TNF, PTGS2, and PRAKA. GO enrichment and KEGG pathway analyses indicated that coumarins in P. decursivum mainly participated in biological processes such as inflammatory response, positive regulation of protein kinase B signaling, chemical carcinogenesis receptor activation, pathways in cancer, and other biological pathways. The molecular docking results indicated that there was good binding between components and targets. This study provides a basis for understanding the spatial distribution and anti-inflammatory mechanism of coumarins in P. decursivum.
A type of unusual interconnected graphitized carbon nanosheets (GCNS) was fabricated from biomass waste, i.e., inner shaddock skins using a facile combined method of simultaneous ...carbonization-activation and post-vacuum-annealing processes. The obtained GCNS has an optimized integration of a cage-like high-aspect-ratio nanosheet structure (∼8 nm thickness), a large surface area of 2327 m2 g−1 and hierarchical meso/micropore systems (82.3% mesopore volume). Given the effect of post-vacuum-annealing process, enhanced graphitization degree and excellent electronic conductivity (7.9 S cm−1) were obtained for the GCNS. The enhanced graphitization degree not only effectively improves electronic/ionic-transport kinetics in favor of rate capability but also prevents electrolyte degradation thus benefitting cyclic life. The ionic liquid-based supercapacitors assembled with symmetric GCNS electrodes exhibited an ultrahigh rate capability of 87% at current density of 100 A g−1 (holding 132 F g−1) and a long cyclic life of 97.6% capacitance retention after 10,000 cycles. The excellent rate capability resulted in an integrated high energy-power property at an energy density of 56 Wh kg−1 (29.2 Wh L−1), corresponding to a power density of 93 kW kg−1 (48.4 kW L−1).
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Stress controllability in thermal and electrical conductivity is important for flexible piezoresistive devices. Due to the strength‐elasticity trade‐off, comprehensive investigation of ...stress‐controllable conduction in elastic high‐modulus polymers is challenging. Here presented is a 3D elastic graphene‐crosslinked carbon nanotube sponge/polyimide (Gw‐CNT/PI) nanocomposite. Graphene welding at the junction enables both phonon and electron transfer as well as avoids interfacial slippage during cyclic compression. The uniform Gw‐CNT/PI comprising a high‐modulus PI deposited on a porous templated network combines stress‐controllable thermal/electrical conductivity and cyclic elastic deformation. The uniform composites show different variation trends controlled by the porosity due to different phonon and electron conduction mechanisms. A relatively high k (3.24 W m−1 K−1, 1620% higher than PI) and suitable compressibility (16.5% under 1 MPa compression) enables the application of the composite in flexible elastic thermal interface conductors, which is further analyzed by finite element simulations. The interconnected network favors a high stress‐sensitive electrical conductivity (sensitivity, 973% at 9.6% strain). Thus, the Gw‐CNT/PI composite can be an important candidate material for piezoresistive sensors upon porosity optimization based on stress‐controllable thermal or electrical conductivity. The results provide insights toward controlling the stress‐induced thermal/electrical conductivities of 3D interconnected templated composite networks for piezoresistive conductors or sensors.
An elasic, flexible, and stress controllable thermal and electrical conductivity of a graphene‐crosslinked carbon nanotube (Gw‐CNT)/polyimide (PI) nanocomposite is developed. A Gw‐CNT network is constructed to provide a continuous conductive network and an elastic template for the rigid PI. The elasticity, thermal conductivity, and electrical conductivity of the resulting composites can be effectively controlled by adjusting the amount of PI.
Flexible and wearable strain sensors based on conductive polymer composites (CPCs) for human motion detection have been highlighted recently. Herein, two flexible conductive composites were ...fabricated by mixing matrix polydimethylsiloxane (PDMS) with zero-dimensional conductive filler carbon black (CB) and one-dimensional carbon nanotubes (CNTs), respectively. A low percolation threshold of CB/PDMS (0.48 vol%) was achieved, while this value was higher than that of CNTs/PDMS (0.13 vol%). In strain-dependent response tests, compared with CNTs/PDMS with a gauge factor (GF) of 4.36 (a strain of 10%), CB/PDMS composites showed a higher sensitivity with a larger GF of 15.75 (a strain of 10%). A good reproducibility was obtained in stretching-releasing process for the two composites. In long-term cyclic test, CB/PDMS showed more stable sensing behaviors, while a slight drifting and fluctuation was observed for CNTs/PDMS. Generally, two composites both possessed satisfactory durability. Mathematical models were proposed to explain the mechanism of the distinct strain sensing behaviors. A smart glove was assembled to monitor the finger motion to evaluate the application of the two composites as flexible strain sensors.
In this study, the ultrasonic-assisted extraction of total coumarins from Peucedanum decursivum (Miq.) Maxim (P. decursivum) via the combination of deep eutectic solvents (DESs) with cellulase ...pretreatment was carried out. Among the 15 kinds of DESs with choline chloride as hydrogen bond acceptors, the DES system of choline chloride/1,4-butanediol with a molar ratio of 1:4 showed the best extraction effect. First, single-factor experiments were performed using the following factors: liquid–solid ratio, pH, enzyme dosage and ultrasonic temperature. The Box–Behnken design (BBD) and response surface methodology (RSM) were employed to optimize the extraction conditions and obtain the following optimal parameter values for the extraction of coumarins from P. decursivum: liquid–solid ratio 14:1 mL/g, pH 5.0, enzyme dosage 0.2%, ultrasonic temperature 60 °C and ultrasonic time 50 min. Under these conditions, the extraction yield of total coumarins from P. decursivum could reach 2.65%, which was close to the predicted extraction yield of 2.68%. Furthermore, the contents of six coumarins, namely, umbelliferone, nodakenin, xanthotoxin, bergapten, imperatorin and decursin were determined to be 0.707 mg·g−1, 0.085 mg·g−1, 1.651 mg·g−1, 2.806 mg·g−1, 0.570 mg·g−1 and 0.449 mg·g−1, respectively, using HPLC-MS after the optimization. In addition, the cell fragmentation of P. decursivum powder obtained using ultrasonic-assisted DES extraction with enzyme pretreatment was found to be the most comprehensive using scanning electron microscopy (SEM), which indicated the highest extraction efficiency for P. decursivum. Finally, the in vitro antioxidant activity of the extracts was evaluated via radical scavenging with 1,1-diphenyl-2-picrylhydrazyl (DPPH), which showed that ultrasonic-assisted DES extraction with enzyme pretreatment exhibited significant antioxidant activity with DPPH radical scavenging of up to 97.90%. This work developed a new and efficient extraction method for coumarins.
The new power system effectively integrates a large number of distributed renewable energy sources, such as solar photovoltaic, wind energy, small hydropower, and biomass energy. This significantly ...reduces the reliance on fossil fuels and enhances the sustainability and environmental friendliness of energy supply. Compared to distribution networks in traditional power systems, the new-generation distribution network offers notable advantages in improving energy efficiency, reliability, environmental protection, and system flexibility, but it also faces a series of new challenges. These challenges include potential harmonic issues introduced by the widespread use of power electronic devices (such as inverters for renewable energy generation systems and electric vehicle charging stations) and the voltage fluctuations and flickering caused by the intermittency and uncertainty of renewable energy generation, which may affect the normal operation of electrical equipment. To address these challenges, this study proposes an optimization model aimed at minimizing network losses and voltage deviations, utilizing traditional capacitor adjustments and static var compensators (SVCs) as optimization measures. Furthermore, this study introduces an improved version of the multi-objective particle swarm optimization (MOPSO) algorithm, specifically enhanced to address the unique challenges of reactive power optimization in modern distribution networks. The test results show that this algorithm can effectively generate a large number of Pareto optimal solutions. The application of this algorithm on a 33-node network case study demonstrates its advantages in reactive power optimization. The optimization results highlight the effectiveness and feasibility of the proposed improved algorithm in the application of distribution network reactive power optimization, offering users a uniform and diverse range of reactive compensation solutions.
Intestinal ischemia-reperfusion (I/R) injury is a life-threatening vascular emergency and has long been a disturbing problem for surgeons. Oxidative stress is considered a vital factor in I/R injury. ...Metformin has anti-oxidative properties and protects against I/R injury. The present study aimed to investigate whether Metformin protects against intestinal I/R injury and reveal the protective mechanism of Metformin. I/R injury was induced in mice by temporary superior mesenteric artery occlusion, and Caco-2 cells were subjected to OGD/R to establish an in vitro model. Different doses of Metformin were administered in vivo and in vitro. We found that I/R injury led to intestinal barrier disruption and cell death by examining histopathological results and the intestinal barrier index, including TER, tight junction proteins and serum biomarkers. We confirmed the existence of pyroptosis in intestinal I/R injury. Moreover, we confirmed the role of pyroptosis in intestinal I/R injury by silencing the gasdermin D (GSDMD). Then, we confirmed that Metformin treatment protected barrier function against intestinal I/R injury and reduced oxidative stress and the inflammatory response. Importantly, Metformin reduced pyroptosis-related proteins, including NLRP3, cleaved caspase-1, and the N-terminus of GSDMD. Knocking down the GSDMD could reversed the protective effects of Metformin, which showed pyroptosis was one of the major cell death pathways controlled by Metformin treatment in setting of intestinal I/R injury. We also discovered that Metformin suppressed the expression of TXNIP and the interaction between TXNIP and NLRP3. We performed siRNA knockdown and found that the protective effects were abolished, which further confirmed our findings. In conclusion, we believe that Metformin protects against intestinal I/R injury in a TXNIP-NLRP3-GSDMD-dependent manner.
•Pyroptosis plays an important role in intestinal I/R injury.•Metformin protects against intestinal I/R injury in mice.•Metformin protects Caco-2 cells subjected to OGD/R.•Metformin inhibits pyroptosis, inflammation and oxidative stress during I/R injury.•Metformin exerts protective effect through TXNIP-NLRP3-GSDMD pathway.
Solar cooling systems are widely used in the building sector, as they can utilize low-grade solar energy to reduce carbon emissions. To improve the thermodynamic performance and economic performance ...of solar cooling systems, solar cooling systems driven by photovoltaic–thermal (PVT) collectors have been widely studied. This paper reviews the recent research on the technological improvement of PVT collectors, the development of thermally driven cooling cycles, and the performance of solar cooling systems driven by PVT collectors. Innovative heat sink structures and the utilization of a high-thermal-conductivity coolant are employed to increase the solar-energy-conversion efficiency of PVT collectors. The use of thermal and mechanical two-stage compression and cascade cooling expands the lower temperature limit of the heat source required for the solar cooling cycle. In addition, specific examples of solar cooling systems driven by PVT collectors are reviewed to explore their thermodynamic and economic performance. Finally, the technical developments in and prospects of different types of PVT collectors and solar cooling systems are explored in an attempt to provide some insight to researchers. This study shows that the PVT collector’s electrical and thermal efficiencies can be improved by 0.85–11% and 1.9–22.02%, compared to those of conventional PV systems and PVT systems based on water cooling, respectively. Furthermore, the lower limit of the heat source temperature for the new thermally driven cooling system expands by 4–20 °C. Finally, the performances of solar cooling systems driven by PVT collectors show a minimum payback period of 8.45–9.3 years, which proves favorable economic feasibility.
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