基于双模态智能鞋的偏瘫患者下肢肌力定量评估

卒中可导致患者下肢运动能力受损和偏瘫。准确评估下肢运动能力对诊断和康复很重要。为了使每次测试都可随时追溯,并避免主观性,我们使用配备有压敏鞋垫和惯性传感单元的双模态智能鞋进行数字化评估,并设计了一个包括左转弯和右转弯的5米步行测试方案。数据收集自23名患者和17名健康受试者。两位医生对所有患者的下肢的运动能力进行了观察,并使用医学研究委员会的五级肌肉检查量表进行了评估。两位医生对同一患者的平均评分被用作真实值。使用我们开发的特征集,在对患者和健康受试者进行分类时达到了100%的准确性。对于患者的肌肉力量,使用我们的特征集和回归方法获得了0.143的平均绝对误差和0.395的最大误差,与每位医生的评分相比(平均绝对误差:0.217,最大误差:0.5),更接近实际情况。因此,我们验证了使用这种智能鞋客观准确地评估中风患者下肢肌肉力量的可能性。

Exponential Time Differencing Method for a Reaction-Diffusion System with Free Boundary

For reaction-diffusion equations in irregular domains with moving boundaries,the numerical stability constraints from the reaction and diffusion terms often require very restricted time step sizes,while complex geometries may lead to difficulties in the accuracy when discretizing the high-order derivatives on grid points near the boundary.It is very challenging to design numerical methods that can efficiently and accurately handle both difficulties.Applying an implicit scheme may be able to remove the stability constraints on the time step,however,it usually requires solving a large global system of nonlinear equations for each time step,and the computational cost could be significant.Integration factor(IF)or exponential time differencing(ETD)methods are one of the popular methods for temporal partial differential equations(PDEs)among many other methods.In our paper,we couple ETD methods with an embedded boundary method to solve a system of reaction-diffusion equations with complex geometries.In particular,we rewrite all ETD schemes into a linear combination of specificФ-functions and apply one state-of-the-art algorithm to compute the matrix-vector multiplications,which offers significant computational advantages with adaptive Krylov subspaces.In addition,we extend this method by incorporating the level set method to solve the free boundary problem.The accuracy,stability,and efficiency of the developed method are demonstrated by numerical examples.

Spectroscopy and carrier dynamics of one-dimensional nanostructures

In recent years,one-dimensional(1D)nanomaterials have raised researcher's interest because of their unique structur-al characteristic to generate and confine the optical signal and their promising prospects in photonic applications.In this re-view,we summarized the recent research advances on the spectroscopy and carrier dynamics of 1D nanostructures.First,the condensation and propagation of exciton-polaritons in nanowires(NWs)are introduced.Second,we discussed the properties of 1D photonic crystal(PC)and applications in photonic-plasmonic structures.Third,the observation of topological edge states in 1D topological structures is introduced.Finally,the perspective on the potential opportunities and remaining chal-lenges of 1D nanomaterials is proposed.

Optical second-harmonic generation of Janus MoSSe monolayer

The transition metal dichalcogenides(TMD)monolayers have shown strong second-harmonic generation(SHG)ow-ing to their lack of inversion symmetry.These ultrathin layers then serve as the frequency converters that can be intergraded on a chip.Here,taking MoSSe as an example,we report the first detailed experimental study of the SHG of Janus TMD monolayer,in which the transition metal layer is sandwiched by the two distinct chalcogen layers.It is shown that the SHG effectively arises from an in-plane second-harmonic polarization under paraxial focusing and detection.Based on this,the orientation-resolved SHG spectroscopy is realized to readily determine the zigzag and armchair axes of the Janus crystal with an accuracy better than±0.6°.Moreover,the SHG intensity is wavelength-dependent and can be greatly enhanced(~60 times)when the two-photon transition is resonant with the C-exciton state.Our findings uncover the SHG properties of Janus MoSSe monolayer,therefore lay the basis for its integrated frequency-doubling applications.

Exciton–polaritons in semiconductors

In 1951,Huang firstly proposed the concept of polariton and derived its dispersion relation by combing lattice vibration in ionic crystals with electromagnetic waves using classic electromagnetic theory,which was primarily aimed to explain light retardation effect (see Fig.1)[1].

SPATIALLY-LOCALIZED SCAFFOLD PROTEINS MAY FACILITATE TO TRANSMIT LONG-RANGE SIGNALS

Scaffold proteins play an important role in the promotion of signal transmission and specificity during cell signaling. In cells, signaling proteins that make up a pathway are often physically orgnaized into complexes by scaffold proteins [1]. Previous work [2] has shown that spatial localization of scaffold can enhance signaling locally while simultaneously suppressing signaling at a distance, and the membrane confinement of scaffold proteins may result in a precipitous spatial gradient of the active product protein, high close to the membrane and low within the cell. However, cell-fate decisions critically depend on the temporal pattern of product protein close to the nucleus. In this paper, when phosphorylation signals cannot be transfered by diffusion only, two mechanisms have been proposed for long-range signaling within cells： multiple locations of scaffold proteins and dynamical movement of scaffold proteins. Thus, here we have unveiled how the spatial propagation of the phosphorylated product protein within a cell depends on the spatially and temporal localized scaffold proteins. A class of novel and fast numerical methods for solving stiff reaction diffusion equations with complex domains is briefly introduced.

Countermeasures for China's Ecological Environment Construction in Land Reclamation

Basic situation of the current ecological environment construction in land consolidation and rehabilitation of China is introduced. The related advanced experience abroad is summarized from mainly four aspects, namely policy, system as well as subject development, planning guidance, design method of project planning and engineering study, and practical countermeasures to China's ecological environment construction in land reclamation are proposed. In terms of policy, system and subject, relevant regulations, policies and system construction should be strengthened and the framework of policy, system and subject development in ecological landscape construction of China's land reclamation should be proposed, integrating ecological environment construction into land reclamation. At the level of strategic planning, the spatial layout and construction key points of green infrastructure in land reclamation of "urban multi-functional developing region, eastern economic developed region, central modern agricultural region and northwestern ecological fragile region" should be achieved. At the level of project planning design, ecological principles, sustainable landscape design principles and vernacular landscape design methods are to be integrated into the planning procedure to form operable technique regulations or introductions. At the level of engineering design, engineering technique system, standards and regulations of ditches, roads, forests and channels with local distinctions should be formulated according to the characters and strategic demands of urbanization, industrialization, agriculture modernization and ecological environment preservation in different regions.

Perovskite quantum dot lasers

Owing to the excellent properties of perovskite quantum dots(QDs),such as an easy synthesis process,high photoluminescence quantum yields,high defect tolerance,and tunable bandgap with different elements,laser actions have been widely conducted.Over the past few years,several approaches have been used for successfully creating perovskite QD lasers.In this review,we summarize the progress of perovskite QD lasers from the aspects of laser theory,characteristics and applications of QD lasers,advantages of perovskite materials for lasers,factors influencing the QD laser threshold,two-photon pumped QD lasers,and perovskite QD laser stability.At the same time,aiming at existing problems,possible solutions and prospects are presented.

Growth of metal halide perovskite materials

Perovskite materials,especially metal halide perovskites,exhibit excellent properties,such as large optical coefficients,high carrier mobilities,long carrier lifetimes,tunable resistivities,large X-ray attenuation coefficients,and simple processing techniques.In recent decades,perovskites have attracted significant attention in the photoelectric field due to their versatile utility in solar cells,light-emitting diodes,photodetectors,X/γ-ray detectors,and lasing.However,the wide applicability of perovskites highly depends on the quality of perovskite crystals and films.Thus far,several perovskite growth technologies and methods have emerged.Therefore,this review classified and summarized the main methods that have been employed to achieve perovskite growth in recent years,including the solution temperaturelowering(STL)method,inverse temperature crystallization(ITC),anti-solvent vapor-assisted crystallization(AVC),spin coating,and chemical vapor deposition(CVD).Through analysis and summary,it has been determined that the STL,ITC,and AVC methods are mainly used to grow high-quality perovskite single crystals.While the spin-coating method has a significant advantage in the preparation of perovskite films,the CVD method is propitious in the fabrication of a variety of morphologies of micro/nano perovskite materials.We hope that this review can be a comprehensive reference for scientific researchers to prepare perovskite-related materials.

Cavity engineering of two-dimensional perovskites and inherent light-matter interaction

Two-dimensional(2D)perovskites are hybrid layered materials in which the inorganic lattice of an octahedron is sandwiched by organic layers.They behave as a quantum-well structure exhibiting large exciton binding energy and high emission efficiency,which is excellent for photonic applications.Hence,the cavity modulation and cavity devices of 2D perovskites are widely investigated.In this review,we summarize the rich photophysics,synthetic methods of different cavity structures,and the cavity-based applications of 2D perovskites.We highlight the strong exciton–photon coupling and photonic lasing obtained in different cavity structures.In addition,functional optoelectronic devices using cavity structures of 2D perovskites are also reviewed.

Integrated hetero-nanoelectrodes for plasmon-enhanced electrocatalysis of hydrogen evolution

Hetero-nanostructures of plasmonic metals and semiconductors have attracted increasing attention in the field of photocatalysis.However,most of the hetero-nanostructured catalysts are randomly arranged and therefore require comprehensive structural design for optimizing their properties.Herein,we report the robust construction of hierarchical hetero-nanostructures where gold(Au)nanorods and molybdenum disulfide(Mo S_(2))quantum sheets(QSs)are integrated in highly ordered arrays.Such construction is achieved through porous anodic alumina(PAA)template-assisted electrodeposition.The as-fabricated hetero-nanostructures demonstrate exciting electrocatalysis towards hydrogen evolution reaction(HER).Both plasmon-induced hot-electron injection and plasmonic scattering/reabsorption mechanisms are determinative to the enhanced electrocatalytic performances.Notably,broadband photoresponses of HER activity in the visible range are observed,indicating their superiority compared with random systems.Such integrated hetero-nanoelectrodes could provide a powerful platform for conversion and utilization of solar energy,meanwhile would greatly prompt the production and exploration of ordered nanoelectrodes.

Lead-free perovskites: growth, properties, and applications

Lead halide perovskites have attracted extensive attention in recent years because of their excellent photoelectronic properties, such as high absorption coefficients,carrier mobilities, defect tolerances, and photoluminescence efficiencies. However, a key issue hindering their commercial application is the toxicity of lead. Replacing lead with other nontoxic elements is a promising solution to this problem.Considering their atomic radii, relative atomic masses, and electron arrangements, perovskites based on Sn, Bi, Sb, and other elements instead of Pb have been widely synthesized.Here, we summarized the growth methods, photoelectric properties, and device applications of these lead-free perovskites. First, we introduced several common growth methods for lead-free perovskites, including solution methods,solid-state reaction, and chemical vapor deposition methods.Second, we discussed the photoelectric properties and methods for optimizing these properties of lead-free perovskites with different structure dimensions. Finally, the applications of lead-free perovskites in solar cells, light-emitting diodes,and X-ray detectors were examined. This review also provides suggestions for future research on lead-free perovskites.

Space-confined and substrate-directed synthesis of transition-metal dichalcogenide nanostructures with tunable dimensionality

Atomically thin transition-metal dichalcogenide(TMDC) nanostructures are predicted to exhibit novel physical properties that make them attractive candidates for the fabrication of electronic and optoelectronic devices. However, TMDCs tend to grow in the form of two-dimensional nanoplates(NPs) rather than one-dimensional nanoribbons(NRs) due to their native layered structure. Herein, we have developed a space-confined and substrate-directed chemical vapor deposition strategy for the controllable synthesis of WS2, WSe2, MoSe2, MoS2, WS2(1-x)Se2x NPs and NRs. TMDC NRs with lengths ranging from several micrometers to 100 μm have been obtained and the widths of TMDC NRs can be effectively tuned.Moreover, we found that TMDC NRs show different growth behaviors on van der Waals(vdW) and nonvd W substrates. The micro-nano structures, optical and electronic properties of synthesized TMDC NRs have been systematically investigated. This approach provides a general strategy for controllable synthesis of TMDC NRs, which makes these materials easily accessible as functional building blocks for novel optoelectronic devices.

Sulfur vs. tellurium: the heteroatom effects on the nonfullerene acceptors

The effect of chalcogen heteroatom variation on donor materials has been systematically investigated. However, this effect on acceptors has rarely been explored. Herein, nonfullerene acceptors BFPSP and BFPTP were reported by simply changing the chalcogen atoms from S to Te. The differences between BFPSP and BFPTP in light absorption, energy levels, excited-state lifetimes, energy loss, charge mobilities, morphology, and photovoltaic properties were systematically investigated to understand the heteroatom effects. More importantly, the electroluminescence spectra, external quantum efficiency of photovoltaics and TDDFTcalculations revealed that the triplet excited state(T1) in energy of BFPTP equals to the charge transfer(CT) state in PBDBT:BFPTP, which allows T1 excitons, generated by intersystem crossing, to split into free charges to contribute to the efficiency.This contribution provides a strategy for tuning the photophysical properties of nonfullerene acceptors and designing high performance triplet materials for OSCs.

An on-Si directional second harmonic generation amplifier for MoS2/WS2 heterostructure

Transition metal dichalcogenides(TMD)heterostructure is widely applied for second harmonic generation(SHG)and holds great promises for laser source,nonlinear switch,and optical logic gate.However,for atomically thin TMD heterostructures,low SHG conversion efficiency would occur due to reduction of light-matter interaction length and lack of phase matching.Herein,we demonstrated a facile directional SHG amplifier formed by MoS2/WS2 monolayer heterostructures suspended on a holey SiO_(2)/Si substrate.The SHG enhancement factor reaches more than two orders of magnitude in a wide spectral range from 355 to 470 nm,and the radiation angle is reduced from 38°to 19°indicating higher coherence and better emission directionality.The giant SHG enhancement and directional emission are attributed to the great excitation and emission field concentration induced by a self-formed vertical Fabry-Pérot microcavity.Our discovery gives helpful insights for the development of two-dimensional(2D)nonlinear optical devices.

Phase/size dual controlled 2D semiconductor In_(2)X_(3)(X=S,Se,Te)for saturable absorption modulation

The production of two-dimensional nanosheets(2D NSs)with all sizes(1-100 nm)and few(<10)layers is highly desired but far from satisfactory.Herein,we report an all-physical top-down method to produce indium chalcogenide(In2X3(X=S,Se,Te))NSs with wide-range(150-3.0 nm)controlled sizes.The method combines silica-assisted ball-milling and sonication-assisted solvent exfoliation to fabricate multiscale NSs with varying distributions,which are then precisely separated by cascade centrifugation.Multiple characterization techniques reveal that the as-produced In2X3 NSs are intrinsic and defect-free and remainβ-phase during the whole process.The redispersions of In2X3 NSs exhibit prominent excitation wavelength-,solvent-,concentration-,and size-dependent photoluminescence.The NSs-poly(methyl methacrylate)(PMMA)hybrid thin films demonstrate strong size effects in nonlinear saturation absorption.The absolute modulation depths of 35.4%,43.3%,47.2%and saturation intensities of 1.63,1.05,0.83 MW·cm^(−2)(i.e.,163,105,and 83 nJ·cm^(−2))are derived for the In_(2)S_(3),In_(2)Se_(3),and In2Te3 quantum sheets,respectively.Our method paves the way for mass production and full exploration of full-scale 2D NSs.

Few-layered organic single-crystalline heterojunctions for high-performance phototransistors

Photogating and electrical gating are key physical mechanisms in organic phototransistors(OPTs).However,most OPTs are based on thick and polycrystalline films,which leads to substantially low efficiency of both photogating and electrical gating and thus reduced photoresponse.Herein,high-performance OPTs based on few-layered organic single-crystalline heterojunctions are proposed and the obstacle of thick and polycrystalline films for photodetection is overcome.Because of the molecular scale thickness of the type I organic single-crystalline heterojunctions in OPTs,both photogating and electrical gating are highly efficient.By synergy of efficient photogating and electrical gating,key figures of merit of OPTs reach the highest among those based on planar heterojunctions so far as we know.The production of few-layered organic single-crystalline heterojunctions will provide a new type of advanced materials for various applications.

Off-hour effect is not significant in endovascular treatment for anterior circulation large vessel occlusion in a multicentre registry

Background and purpose Whether the off-hour effect has an impact on workflow and outcomes of endovascular treatment(EVT)for anterior circulation large vessel occlusion(AC-LVO)remains uncertain.This study aimed to compare the characteristics and outcomes of patients who presented or were treated during off-hour versus on-hour in a multi-center registry.Methods AC-LVO patients from 21 centres were categorised into the off-hour group and the on-hour group.Off-hour(weekends,holidays,and 18:00-7:59 on weekdays)and on-hour(8:00-17:59 on weekdays except for holidays)were defined according to arrival and groin-puncture time points,respectively.Subgroup comparisons between patients both arrived and treated during off-hour(true off-hour)and on-hour(true on-hour)were performed.The primary outcome was the 90-day modified Rankin Scale(mRS)score.Secondary outcomes included favourable outcome(mRS 0-2 at 90 days),EVT-related time metrics,and other clinical outcomes.Ordinary and binary logistic regression and linear regression were taken to adjust for confounding factors.Results Of all 698 patients enrolled,435(62.3%)and 456(65.3%)patients were categorised into the off-hour arrival and off-hour puncture group,respectively.Shorter onset to door time(adjustedßcoefficient:−21.56;95%CI−39.96 to−3.16;p=0.022)was noted in the off-hour arrival group.Ordinal and dichotomous mRS scores at 90 days were comparable between the off-hour group and the on-hour group regardless of off-hour definitions.Other time metrics and outcomes were comparable between the two groups.Of 595 patients both presented and were treated during off-hour or on-hour,394 patients were categorised into the true off-hour group and 201 into the true on-hour group.Time metrics and clinical outcomes were similar between the true off-hour and the true on-hour group.Conclusions The off-hour effect was not significant regarding clinical outcomes and in-hospital workflow in AC-LVO patients receiving EVT in this Chinese multicentre registry.

Phase-modulated quantum-sized TMDs for extreme saturable absorption

Two-dimensional semiconductors such as transition metal dichalcogenides(TMDs)have attracted much interest in the past decade.Herein,we present an all-physical top-down method for the scalable production of the intrinsic TMD quantum sheets(QSs).The phases of the TMDs(e.g.,2H-MoSe_(2),2H-WSe_(2),and Td-WTe2)remain stable during the transformation from bulk to QSs.However,phase transition(from Td to 2H)is detected in MoTe2.Such phase-modulation by size-reduction has never been reported before.The TMD QSs can be well dispersed in solvents,resulting in remarkable photoluminescence with excitation wavelength-,concentration-,and solvent-dependence.Meanwhile,the TMD QSs can be readily solution-processed into hybrid thin films,which demonstrate exceptional nonlinear saturation absorption(NSA).Notably,2H-MoTe2 QSs in poly(methyl methacrylate)show extremely high NSA performance with(absolute)modulation depth up to 46.6%and saturation intensity down to 0.81 MW·cm^(−2).Our work paves the way towards quantum-sized TMDs.

Strong in-plane optical anisotropy in 2D van der Waals antiferromagnet VOCl

Two-dimensional(2D)van der Waals(vdW)magnetic materials with strong in-plane anisotropy can make possible novel applications such as optospintronics and strain sensors.In this work,the strong in-plane optical anisotropy in 2D vdW antiferromagnet VOCl has been systematically investigated.The optical brightness and absorption coefficient exhibit evident periodic variation with the change of incident polarization,unveiling the strong in-plane anisotropic optical absorption.The Raman intensity in this material shows obvious dependence on the polarization angle of incident laser,demonstrating that the phonon properties possess strong in-plane anisotropy.Besides,we have also realized in-situ visualization of in-plane optical reflection anisotropy in this material.Moreover,the strong second harmonic generation(SHG)signal can only be detected when the incident polarization is along specific in-plane crystal orientations,illustrating the presence of strong in-plane nonlinear optical anisotropy.These findings will benefit the applications of VOCl in the field of polarization-dependent electronics and spintronics.