Lamellar-stacked cobalt-based nanopiles integrated with nitrogen/sulfur co-doped graphene as a bifunctional electrocatalyst for ultralong-term zinc-air batteries

Sluggish oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)kinetics inevitably impede the practical performance of rechargeable zinc-air batteries.Thus,combing the structural designability of transition metal-based electrocatalysts with anionic regulation is highly desired.Herein,mesoporous lamellar-stacked cobalt-based nanopiles with surface-sulfurization modification are elaborately designed and integrated with N/S co-doped graphene to build a robust OER/ORR bifunctional electrocatalyst.The lamellar-stacking mode of mesoporous nanosheets with abundant channels accelerates gas-liquid mass transfer,and partial-sulfurization of cobalt-based matrix surface efficiently improves the intrinsic OER activity.Meanwhile,N/S co-doped graphene further reinforces the ORR active sites while providing a stable conductive skeleton.As expected,this composite electrocatalyst delivers considerable bifunctional activity and stability,with an OER overpotential of 323 m V at 10 m A cm^(-2)and high durability.When applied in zinc-air batteries,remarkable ultralong-term stability over 4000 cycles and a maximum power density of 150.1 m W cm^(-2)are achieved.This work provides new insight into structurecomposition synergistic design of rapid-kinetics OER/ORR bifunctional electrocatalyst for nextgeneration metal-air batteries.

MicroRNA-188-5p targeting Forkhead Box L1 promotes colorectal cancer progression via activating Wnt/β-catenin signaling

Objective:MicroRNA-188-5p(miR-188)enhances oncologic progression in various human malignancies.This study aimed to explore its role in colorectal cancer(CRC).Materials and Methods:Human CRC tissues paired with normal tissues,and several CRC cell lines were utilized.Real-time quantitative PCR was applied to measure the expression of miR-188.Overexpression and knockdown were used to access the function of miR-188 and to investigate whether FOXL1/Wnt signaling mediates such function.The proliferation,migration and invasion of cancer cells were evaluated by CCK8,wound-healing and transwell assays,respectively.Whether FOXL1 acted as a direct target of miR-188 was verified by dual-luciferase reporter assays.Results:Levels of miR-188 were upregulated in CRC tissues than in paired-normal tissues,as well as in various CRC cell lines.High expression of miR-188 was strongly associated with advanced tumor stage,accompanied with significant tumor cell proliferation,invasion and migration.It was confirmed that FOXL1 played positive crosstalk between miR-188 regulation and downstream Wnt/β-catenin signaling activation.Conclusions:All findings indicate that miR-188 promotes CRC cell proliferation and invasion through targeting FOXL1/Wnt signaling and could be served as a potential therapeutic target for human CRC in the future.

Enhanced wide-angle third-harmonic generation in flat-band-engineered quasi-BIC metagratings

Nonlinear metasurfaces and photonic crystals provide a significant way to generate and manipulate nonlinear signals owing to the resonance-and symmetry-based light-matter interactions supported by the artificial structures.However,the nonlinear conversion efficiency is generally limited by the angular dispersion of optical resonances especially in nonparaxial photonics.Here,we propose a metagrating realizing a quasi-bound-state in the continuum in a flat band to dramatically improve the third harmonic generation(THG)efficiency.A superior operating angular range is achieved based on the interlayer and intralayer couplings,which are introduced by breaking the mirror symmetry of the metagrating.We demonstrate the relation of angular dispersion between the nonlinear and linear responses at different incident angles.We also elucidate the mechanism of these offaxis flat-band-based nonlinear conversions through different mode decomposition.Our scheme provides a robust and analytical way for nonparaxial nonlinear generation and paves the way for further applications such as wide-angle nonlinear information transmission and enhanced nonlinear generation under tight focusing.

Few-layer metasurfaces with arbitrary scattering properties

Metasurfaces,which are planar arrays of subwavelength artificial structures,have emerged as excellent platforms for the integration and miniaturization of electromagnetic devices and provided ample possibilities for single-dimensional and multi-dimensional manipulations of electromagnetic waves.However,owing to the limited interactions between planar thin metallic nanostructures and electromagnetic waves as well as intrinsic losses in metals,metasurfaces exhibit disadvantages in terms of efficiency,controllability,and functionality.Recent advances in this field show that few-layer metasurfaces can overcome these drawbacks.Few-layer metasurfaces composed of more than one functional layer enable more degrees of design freedom.Hence,they possess unprecedented capabilities for electromagnetic wave manipulation,which have considerable impact in the area of nanophotonics.This article reviews recent advances in few-layer metasurfaces from the viewpoint of their scattering properties.The scattering matrix theory is briefly introduced,and the advantages and drawbacks of few-layer metasurfaces for the realization of arbitrary scattering properties are discussed.Then,a detailed overview of typical few-layer metasurfaces with various scattering properties and their design principles is provided.Finally,an outlook on the future directions and challenges in this promising research area is presented.

Electromagnetic wave manipulation based on few-layer metasurfaces and polyatomic metasurfaces

Metasurfaces,whose electromagnetic(EM)responses can be artificially designed,are two-dimensional arrays composed of subwavelength nanostructures.Accompanied by various fascinating developments in the past decade,metasurfaces have been proved as a powerful platform for the implementation of EM wave manipula-tion.However,the planar monoatomic metasurfaces widely used in previous works have limited design freedoms,resulting in some disadvantages for the realization of high-performance and new functional EM wave control.The latest developments show that few-layer metasurfaces and polyatomic metasurfaces are good alternatives to overcome the drawbacks of planar monoatomic metasurfaces and realize high-efficient,multi-band and broad-band EM functionalities.They provide additional degrees of design freedom via introducing multilayer layouts or combining multiple meta-atoms into a unit cell respectively.Here,recent advances of few-layer and polyatomic metasurfaces are reviewed.The design strategies,EM properties and main advantages of few-layer metasurfaces and polyatomic metasurfaces are overviewed firstly.Then,few-layer metasurfaces and polyatomic metasurfaces in recent progress for EM wave manipulation are classified and discussed from the viewpoint of their design strategy.At last,an outlook on future development trends and potential applications in these fast-developing research areas is presented.