查看更多>>摘要：China,one of the most populous countries in the world,has suffered the highest number of natural disaster-related deaths from fire.On local scales,the main causes of urban fires are anthropogenic in nature.Yet,on regional to national scales,little is known about the indicators of large-scale co-varying urban fire activity in China.Here,we present the China Fire History Atlas(CFHA),which is based on 19 947 documentary records and represents fires in urban areas of China over the twentieth century(1901-1994).We found that temperature variability is a key indicator of urban fire activity in China,with warmer temperatures being correlated with more urban fires,and that this fire-temperature relationship is seasonally and regionally explicit.In the early twentieth century,however,the fire-temperature relationship was overruled by war-related fires in large urban areas.We further used the fire-temperature relationship and multiple emissions scenarios to project fire activity across China into the twenty-first century.Our projections show a distinct increase in future urban fire activity and fire-related economic loss.Our findings provide insights into fire-climate relationships in China for densely-populated areas and on policy-relevant time scales and they contribute spatial coverage to efforts to improve global fire models.
查看更多>>摘要：The phase of secular evolution of continents is manifested as the degree of compositional differentiation,modification and maturation of continental crusts,which is vital in understanding the mechanism of continental evolution but is difficult to quantify.Here we use integrated passive-and active-source seismic profiling to conduct joint analysis and inversion and derive Vs and Vp/Vs section models across the North China Craton(NCC)to southeastern Altaids boundary zone that bears a tectonic transition from a reworked ancient craton margin to a Phanerozoic accretionary orogen.We systematically exploited the imaged multiple physical properties as precise and delicate proxies to constrain the compositional architecture in the crust across this important tectonic transition subject to various crustal evolutional phases.Our Vs and Vp/Vs imaging,together with the existing isotopic data,characterizes the Yin Shan-Yan Shan belt as the northern NCC margin with layered homogeneous compositions that point to an evolved crust.However,the lower-crustal low-Vs/high-Vp/Vs signature that overlaps the shallowly dipping to horizontal reflective fabrics suggests that the crust of the northern NCC margin has undergone considerable reworking through lower-crustal-stretching-assisted melt migration and mixing since the late Paleozoic to Mesozoic eras.The process probably involved crust-mantle interaction and thus resulted in a compositionally modified ancient crustal basement.On the contrary,the southeastern Altaids domain manifests crustal complexity in compositions and structures inferred to be indicative of a juvenile crust of the Phanerozoic accretionary orogen.Our results provide deep physical-property constraints that shed new light on the crustal evolution of a complex craton margin.
查看更多>>摘要：Fast optical modulation of nanoplasmonics is fundamental for on-chip integration of all-optical devices.Although various strategies have been proposed for dynamic modulation of surface plasmons,critical issues of device compatibility and extremely low efficiency in the visible spectrum hamper the application of optoplasmonic nanochips.Here we establish an optoplasmonic system based on Au@Cu2-xS hybrid core-shell nanoparticles.The optical excitation of hot electrons and their charge transfer to the semiconductor coating(Cu2-xS)lead to lowered electron density of Au,which results in the red shift of the localized surface plasmon resonance.The hot electrons can also transport through the Cu2-xS layer to the metal substrate,which increases the conductance of the nanogap.As such,the coupled gap plasmon blue-shifts with a magnitude of up to～15 nm,depending on the excitation power and the thickness of the coatings,which agrees with numerical simulations.All of this optoelectronic tuning process is highly reversible,controllable and fast with a modulated laser beam,which is highly compatible and sufficiently useful for on-chip integration of nanophotonic devices.
查看更多>>摘要：Superconducting phase transitions in two dimensions lie beyond the description of the Ginzburg-Landau symmetry-breaking paradigm for three-dimensional superconductors.They are Berezinskii-Kosterlitz-Thouless(BKT)transitions of paired-electron condensate driven by the unbinding of topological excitations,i.e.vortices.The recently discovered monolayers of layered high-transition-temperature(Tc)cuprate superconductor Bi2Sr2CaCu2O8+δ(Bi2212)meant that this 2D superconductor promised to be ideal for the study of unconventional superconductivity.But inhomogeneity posed challenges for distinguishing BKT physics from charge correlations in this material.Here,we utilize the phase sensitivity of scanning superconducting quantum interference device microscopy susceptometry to image the local magnetic response of underdoped Bi2212 from the monolayer to the bulk throughout its phase transition.The monolayer segregates into domains with independent phases at elevated temperatures below Tc.Within a single domain,we find that the susceptibility oscillates with flux between diamagnetism and paramagnetism in a Fraunhofer-like pattern up to Tc.The finite modulation period,as well as the broadening of the peaks when approaching Tc from below,suggests well-defined vortices that are increasingly screened by the dissociation of vortex-antivortex plasma through a BKT transition.In the multilayers,the susceptibility oscillation differs in a small temperature regime below Tc,consistent with a dimensional crossover led by interlayer coupling.Serving as strong evidence for BKT transition in the bulk,we observe a sharp jump in phase stiffness and paramagnetism at small fields just below Tc.These results unify the superconducting phase transitions from the monolayer to the bulk underdoped Bi2212,and can be collectively referred to as the BKT transition with interlayer coupling.
查看更多>>摘要：Flexible sensors have been developed for the perception of various stimuli.However,complex deformation,usually resulting from forces or strains from multi-axes,can be challenging to measure due to the lack of independent perception of multiaxial stimuli.Herein,flexible sensors based on the metamaterial membrane with zero Poisson's ratio(ZPR)are proposed to achieve independent detection of biaxial stimuli.By deliberately designing the geometric dimensions and arrangement parameters of elements,the Poisson's ratio of an elastomer membrane can be modulated from negative to positive,and the ZPR membrane can maintain a constant transverse dimension under longitudinal stimuli.Due to the accurate monitoring of grasping force by ZPR sensors that are insensitive to curvatures of contact surfaces,rigid robotic manipulators can be guided to safely grasp deformable objects.Meanwhile,the ZPR sensor can also precisely distinguish different states of manipulators.When ZPR sensors are attached to a thermal-actuation soft robot,they can accurately detect the moving distance and direction.This work presents a new strategy for independent biaxial stimuli perception through the design of mechanical metamaterials,and may inspire the future development of advanced flexible sensors for healthcare,human-machine interfaces and robotic tactile sensing.
查看更多>>摘要：Esophageal squamous cell carcinoma(ESCC)is a poor-prognostic cancer type with extensive intra-and inter-patient heterogeneity in both genomic variations and tumor microenvironment(TME).However,the patterns and drivers of spatial genomic and microenvironmental heterogeneity of ESCC remain largely unknown.Here,we generated a spatial multi-omic atlas by whole-exome,transcriptome,and methylome sequencing of507 tumor samples from 103 patients.We identified a novel tumor suppressor PREX2,accounting for 22％of ESCCs with frequent somatic mutations or hyper-methylation,which promoted migration and invasion of ESCC cells in vitro.Analysis of the TME and quantification of subclonal expansion indicated that ESCCs undergo spatially directed evolution,where subclones mostly originated from the tumor center but had a biased clonal expansion to the upper direction of the esophagus.Interestingly,we found upper regions of ESCCs often underwent stronger immunoediting with increased selective fitness,suggesting more stringent immune selection.In addition,distinct TMEs were associated with variable genomic and clinical outcomes.Among them,hot TME was associated with high immune evasion and subclonal heterogeneity.We also found that immunoediting,instead of CD8+T cell abundance,acts as an independent prognostic factor of ESCCs.Importantly,we found significant heterogeneity in previously considered potential therapeutic targets,as well as BRCAness characteristics in a subset of patients,emphasizing the importance of focusing on heterogeneity in ESCC targeted therapy.Collectively,these findings provide novel insights into the mechanisms of the spatial evolution of ESCC and inform precision therapeutic strategies.
查看更多>>摘要：Octopamine(OA),analogous to norepinephrine in vertebrates,is an essential monoamine neurotransmitter in invertebrates that plays a significant role in various biological functions,including olfactory associative learning.However,the spatial and temporal dynamics of OA in vivo remain poorly understood due to limitations associated with the currently available methods used to detect it.To overcome these limitations,we developed a genetically encoded GPCR activation-based(GRAB)OA sensor called GRABOA1.0.This sensor is highly selective for OA and exhibits a robust and rapid increase in fluorescence in response to extracellular OA.Using GRABOA1.0,we monitored OA release in the Drosophila mushroom body(MB),the fly's learning center,and found that OA is released in response to both odor and shock stimuli in an aversive learning model.This OA release requires acetylcholine(ACh)released from Kenyon cells,signaling via nicotinic ACh receptors.Finally,we discovered that OA amplifies aversive learning behavior by augmenting dopamine-mediated punishment signals via Octβ1R in dopaminergic neurons,leading to alterations in synaptic plasticity within the MB.Thus,our new GRABOA1.0 sensor can be used to monitor OA release in real time under physiological conditions,providing valuable insights into the cellular and circuit mechanisms that underlie OA signaling.
查看更多>>摘要：Quantitative analysis of activated neurons in mouse brains by a specific stimulation is usually a primary step to locate the responsive neurons throughout the brain.However,it is challenging to comprehensively and consistently analyze the neuronal activity trace in whole brains of a large cohort of mice from many terabytes of volumetric imaging data.Here,we introduce NEATmap,a deep learning-based high-efficiency,high-precision and user-friendly software for whole-brain neuronal activity trace mapping by automated segmentation and quantitative analysis of immunofluorescence labeled c-Fos+neurons.We applied NEATmap to study the brain-wide differentiated neuronal activation in response to physical and psychological stressors in cohorts of mice.
查看更多>>摘要：Electrocatalytic oxidation of alcohols using heterogeneous catalysts is a promising aqueous,energy-efficient and environmentally friendly approach,especially for coupling different alcohols to prolong the carbon chain via co-oxidation.Precisely regulating critical steps to tailor electrode materials and electrolyte composition is key to selectively coupling alcohols for targeted synthesis.However,selectively coupling different alcohols remains challenging due to the lack of effective catalyst and electrolyte design promoting specific pathways.Herein,we demonstrate a paired electrolysis strategy for combining anodic oxidative coupling of ethanol(EtOH)and benzyl alcohol(PhCH2OH)to synthesize cinnamaldehyde(CAL)and cathodic ammonia production.The strategies involve:(ⅰ)utilizing the salt-out effect to balance selective oxidation and coupling rates;(ⅱ)developing platinum-loaded nickel hydroxide electrocatalysts to accelerate intermediate coupling kinetics;(ⅲ)introducing thermodynamically favorable nitrate reduction at the cathode to improve coupling selectivity by avoiding hydrogenation of products while generating valuable ammonia instead of hydrogen.We achieved 85％coupling selectivity and 278 μmol/h NH3 productive rate at 100 mA/cm2 with a low energy input(～1.63 V).The membrane-free,low energy,scalable approach with a wide substrate scope highlights promising applications of this methodology.This work advances heterogeneous electrocatalytic synthesis through rational design principles that integrate anodic oxidative coupling with cathodic nitrate reduction reactions,having synergistic effects on efficiency and selectivity.
查看更多>>摘要：The photoinduced dipole force(PiDF)is an attractive force arising from the Coulombic interaction between the light-induced dipoles on the illuminated tip and the sample.It shows extreme sample-tip distance and refractive index dependence,which is promising for nanoscale infrared(IR)imaging of ultrathin samples.However,the existence of PiDF in the mid-IR region has not been experimentally demonstrated due to the coexistence of photoinduced thermal force(PiTF),typically one to two orders of magnitude higher than PiDF.In this study,we demonstrate that,with the assistance of surface phonon polaritons,the PiDF of c-quartz can be enhanced to surpass its PiTF,enabling a clear observation of PiDF spectra reflecting the properties of the real part of permittivity.Leveraging the detection of the PiDF of phonon polaritonic substrate,we propose a strategy to enhance the sensitivity and contrast of photoinduced force responses in transmission images,facilitating the precise differentiation of the heterogeneous distribution of ultrathin samples.
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