Nonlinear optical frequency mixing,which describes new frequencies generation by exciting nonlinear materials with intense light field,has drawn vast interests in the field of photonic devices,material characterizatio...Nonlinear optical frequency mixing,which describes new frequencies generation by exciting nonlinear materials with intense light field,has drawn vast interests in the field of photonic devices,material characterization,and optical imaging.Investigating and manipulating the nonlinear optical response of target materials lead us to reveal hidden physics and develop applications in optical devices.Here,we report the realization of facile manipulation of nonlinear optical responses in the example system of MoS_(2) monolayer by van der Waals interfacial engineering.We found that,the interfacing of monolayer graphene will weaken the exciton oscillator strength in MoS_(2) monolayer and correspondingly suppress the second harmonic generation(SHG)intensity to 30%under band-gap resonance excitation.While with off-resonance excitation,the SHG intensity would enhance up to 130%,which is conjectured to be induced by the interlayer excitation between MoS_(2) and graphene.Our investigation provides an effective method for controlling nonlinear optical properties of two-dimensional materials and therefore facilitates their future applications in optoelectronic and photonic devices.展开更多
An ultimate goal of neuroscience is to decipher the principles underlying neuronal information processing at the molecular,cellular,circuit,and system levels.The advent of miniature fluorescence microscopy has further...An ultimate goal of neuroscience is to decipher the principles underlying neuronal information processing at the molecular,cellular,circuit,and system levels.The advent of miniature fluorescence microscopy has furthered the quest by visualizing brain activities and structural dynamics in animals engaged in self-determined behaviors.In this brief review,we summarize recent advances in miniature fluorescence microscopy for neuroscience,focusing mostly on two mainstream solutions-miniature single-photon microscopy,and miniature two-photon microscopy.We discuss their technical advantages and limitations as well as unmet challenges for future improvement.Examples of preliminary applications are also presented to reflect on a new trend of brain imaging in experimental paradigms involving body movements,long and complex protocols,and even disease progression and aging.展开更多
The Lateral resolution (LR) and signal-to-noise ratio (SNR) are the essential factors in the applications of scanning probe microscopy in quantitative measurement of surface charge distribution,potential profile,and d...The Lateral resolution (LR) and signal-to-noise ratio (SNR) are the essential factors in the applications of scanning probe microscopy in quantitative measurement of surface charge distribution,potential profile,and dielectric properties.We use a model system to comprise Au nanoparticles (NPs) embedded in a polystyrene (PS) matrix to study the effects of various experimental parameters,such as modulation bias voltage,tip-sample distance,and actual tip shape,on the electrostatic interactions between the tips and samples.The results show that LR and SNR decrease when the tip-sample distance increases,while SNR increases with tip modulation voltage.LR is less sensitive to tip modulation voltage,but shows complex dependence on the sample geometric structure.In combination with a numerical simulation based on the integral capacitance model,the electrostatic force interaction between tip and sample was quantitatively analyzed.展开更多
Understanding the impact of carbon markets on the economic and environmental performance of power generation enterprises is important for improving carbon market policies and achieving the carbon peaking and carbon ne...Understanding the impact of carbon markets on the economic and environmental performance of power generation enterprises is important for improving carbon market policies and achieving the carbon peaking and carbon neutrality goals.This paper utilizes data from power generation enterprises between 2010 and 2022 and employs a difference-in-differences model to estimate the effects of carbon market participation.We further examine heterogeneity and identify underlying mechanisms from regional,market,management,and technological perspectives.The results indicate that carbon market policies act as a“double-edged sword”:they significantly reduce carbon emissions while diminishing firms’return on total assets.Regional analysis reveals stronger effects in economically advanced eastern provinces.On the market side,carbon trading tightens financing constraints and reduces liquidity;on the management side,it increases management expenses and boosts disclosures of internal control audits;and on the technological side,it drives higher research and development investment and patenting activity,reflecting intensified innovation under emissions pressure.These results provide a basis for future research on the long-term corporate impacts of carbon markets and offer policy recommendations for designing robust,equitable trading systems.展开更多
Drought stress is a major environmental factor that limits the growth, development, and yield of rice(Oryza sativa L.). Histone deacetylases(HDACs) are involved in the regulation of drought stress responses. HDA704 is...Drought stress is a major environmental factor that limits the growth, development, and yield of rice(Oryza sativa L.). Histone deacetylases(HDACs) are involved in the regulation of drought stress responses. HDA704 is an RPD3/HDA1 class HDAC that mediates the deacetylation of H4K8(lysine 8of histone H4) for drought tolerance in rice. In this study, we show that plants overexpressing HDA704(HDA704-OE) are resistant to drought stress and sensitive to abscisic acid(ABA), whereas HDA704 knockout mutant(hda704) plants displayed decreased drought tolerance and ABA sensitivity.Transcriptome analysis revealed that HDA704 regulates the expression of ABA-related genes in response to drought stress. Moreover, HDA704 was recruited by a drought-resistant transcription factor,WAX SYNTHESIS REGULATORY 2(Os WR2), and co-regulated the expression of the ABA biosynthesis genes NINE-CIS-EPOXYCAROTENOID DIOXYGENASE 3(NCED3), NCED4, and NCED5 under drought stress. HDA704 also repressed the expression of ABA-INSENSITIVE 5(Os ABI5) and DWARF AND SMALL SEED 1(Os DSS1) by regulating H4K8ac levels in the promoter regions in response to polyethylene glycol 6000 treatment. In agreement, the loss of Os ABI5 function increased resistance to dehydration stress in rice. Our results demonstrate that HDA704 is a positive regulator of the drought stress response and offers avenues for improving drought resistance in rice.展开更多
The "solidified liquid layer" model has been examined using a quartz crystal microbalance(QCM) with a polymeric matrix.The model is shown to give a reasonable explanation for the following experimental obser...The "solidified liquid layer" model has been examined using a quartz crystal microbalance(QCM) with a polymeric matrix.The model is shown to give a reasonable explanation for the following experimental observations:(i) The opposite response of the QCM and surface plasmon resonance(SPR) for the activation process;(ii) the marked difference in the responses for IgG/anti-IgG interaction between QCM and SPR.Theoretical analysis and experimental results indicated that QCM is sensitive to the thickness change of the "solidified liquid layer" but not the mass of captured biomolecules(i.e.,the immobilized mass),implying caution must be taken in interpreting QCM results.展开更多
The binding behaviors of three structurally similar and flexible cages to a series of quaternary ammonium ions have been systematically studied.The cage with phenyl sidewalls is new;moreover,its structure and conforma...The binding behaviors of three structurally similar and flexible cages to a series of quaternary ammonium ions have been systematically studied.The cage with phenyl sidewalls is new;moreover,its structure and conformational states have been characterized by NMR;2D NMR,and X-ray crystallography.The results reveal that the three cages show quite high binding affinities and selectivities to different vips.Enthalpy-entropy compensation was invoked to explain the different binding performance.Moreover,a six-component,high-fidelity self-sorting system was successfully constructed by using these cages and three vips.This suggests that conformationally flexible hosts may also achieve high binding affinities and selectivities,which is in contrast to the traditional point of view-only preorganized and rigid hosts are able to do so.This research advocates that conformational flexibility should also be seriously considered in host design.展开更多
Gold nanoparticles(Au NPs)have demonstrated great potential in chemical and biological sensing,catalysis,biomedicine,X-ray computed tomography,and other applications,owing to their unique properties.Au NPs with high-i...Gold nanoparticles(Au NPs)have demonstrated great potential in chemical and biological sensing,catalysis,biomedicine,X-ray computed tomography,and other applications,owing to their unique properties.Au NPs with high-index facets have attracted more attention in the past decade owing to their superior electrocatalytic activity in fuel cells and enhanced performance in surface-enhanced Raman spectroscopy(SERS)applications.This review presents an overview of our achievements in the direct synthesis of Au NPs with controlled shapes in water using cationic surfactants.By deliberately adjusting the nature of the surfactant stabilizers,preformed Au NPs with simple shapes can be readily transformed into Au NPs with complicated shapes with controlled high-index facets by simple seeded growth.The high-index facets of the as-prepared Au NPs can be consistently correlated with their superior performance in the electrooxidation of methanol and ethanol and their enhanced SERS activity.展开更多
Human primed pluripotent stem cells are capable of generating all the embryonic lineages.However,their extraembryonic trophectoderm potentials are limited.It remains unclear how to expand their developmental potential...Human primed pluripotent stem cells are capable of generating all the embryonic lineages.However,their extraembryonic trophectoderm potentials are limited.It remains unclear how to expand their developmental potential to trophectoderm lineages.Here we show that transient treatment with a cocktail of small molecule epigenetic modulators imparts trophectoderm lineage potentials to human primed pluripotent stem cells while preserving their embryonic potential.These chemically treated cells can generate trophectoderm-like cells and downstream trophoblast stem cells,diverging into syncytiotrophoblast and extravillous trophoblast lineages.Transcriptomic and CUT&Tag analyses reveal that these induced cells share transcriptional profiles with in vivo trophectoderm and cytotrophoblast,and exhibit reduced H3K27me3 modification at gene loci specific to trophoblast lineages compared with primed pluripotent cells.Mechanistic exploration highlighted the critical roles of epigenetic modulators HDAC2,EZH1/2,and KDM5s in the activation of trophoblast lineage potential.Our findings demonstrate that transient epigenetic resetting activates unrestricted lineage potential in human primed pluripotent stem cells,and offer new mechanistic insights into human trophoblast lineage specification and in vitro models for studying placental development and related disorders.展开更多
基金Project supported by Beijing Natural Science Foundation,China(Grant No.JQ19004)Beijing Excellent Talents Training Support,China(Grant No.2017000026833ZK11)+8 种基金the National Natural Science Foundation of China(Grant Nos.52025023,51991340,and 51991342)the National Key Research and Development Program of China(Grant Nos.2016YFA0300903 and 2016YFA0300804)the Key R&D Program of Guangdong Province,China(Grant Nos.2019B010931001,2020B010189001,2018B010109009,and 2018B030327001)the Beijing Municipal Science&Technology Commission,China(Grant No.Z191100007219005)the Beijing Graphene Innovation Program(Grant No.Z181100004818003)Bureau of Industry and Information Technology of Shenzhen(Graphene platform 201901161512)Guangdong Innovative and Entrepreneurial Research Team Program(Grant No.2016ZT06D348)the Science,Technology and Innovation Commission of Shenzhen Municipality(Grant No.KYTDPT20181011104202253)the China Postdoctoral Science Foundation(Grant No.2020M680177)。
文摘Nonlinear optical frequency mixing,which describes new frequencies generation by exciting nonlinear materials with intense light field,has drawn vast interests in the field of photonic devices,material characterization,and optical imaging.Investigating and manipulating the nonlinear optical response of target materials lead us to reveal hidden physics and develop applications in optical devices.Here,we report the realization of facile manipulation of nonlinear optical responses in the example system of MoS_(2) monolayer by van der Waals interfacial engineering.We found that,the interfacing of monolayer graphene will weaken the exciton oscillator strength in MoS_(2) monolayer and correspondingly suppress the second harmonic generation(SHG)intensity to 30%under band-gap resonance excitation.While with off-resonance excitation,the SHG intensity would enhance up to 130%,which is conjectured to be induced by the interlayer excitation between MoS_(2) and graphene.Our investigation provides an effective method for controlling nonlinear optical properties of two-dimensional materials and therefore facilitates their future applications in optoelectronic and photonic devices.
基金We thank Dr.Zhe Zhao and Dr.Haitao Wu for helping with the experiments for Fig.2D,and Dr.Weijian Zong for discussion.This work was supported by grants from the National Natural Science Foundation of China(31327901,31570839,61975002,31830036,31821091,and 8182780030)the Major State Basic Research Program of China(2016 YFA0500400 and 2016YFA0500403)and the National Postdoctoral Program for Innovative Talents of China(BX20190011).
文摘An ultimate goal of neuroscience is to decipher the principles underlying neuronal information processing at the molecular,cellular,circuit,and system levels.The advent of miniature fluorescence microscopy has furthered the quest by visualizing brain activities and structural dynamics in animals engaged in self-determined behaviors.In this brief review,we summarize recent advances in miniature fluorescence microscopy for neuroscience,focusing mostly on two mainstream solutions-miniature single-photon microscopy,and miniature two-photon microscopy.We discuss their technical advantages and limitations as well as unmet challenges for future improvement.Examples of preliminary applications are also presented to reflect on a new trend of brain imaging in experimental paradigms involving body movements,long and complex protocols,and even disease progression and aging.
基金Supported by the Ministry of Science and Technology of China(No 2010DFA54310)the National Science Foundation of China(Nos 20973046,60911130231).
文摘The Lateral resolution (LR) and signal-to-noise ratio (SNR) are the essential factors in the applications of scanning probe microscopy in quantitative measurement of surface charge distribution,potential profile,and dielectric properties.We use a model system to comprise Au nanoparticles (NPs) embedded in a polystyrene (PS) matrix to study the effects of various experimental parameters,such as modulation bias voltage,tip-sample distance,and actual tip shape,on the electrostatic interactions between the tips and samples.The results show that LR and SNR decrease when the tip-sample distance increases,while SNR increases with tip modulation voltage.LR is less sensitive to tip modulation voltage,but shows complex dependence on the sample geometric structure.In combination with a numerical simulation based on the integral capacitance model,the electrostatic force interaction between tip and sample was quantitatively analyzed.
文摘Understanding the impact of carbon markets on the economic and environmental performance of power generation enterprises is important for improving carbon market policies and achieving the carbon peaking and carbon neutrality goals.This paper utilizes data from power generation enterprises between 2010 and 2022 and employs a difference-in-differences model to estimate the effects of carbon market participation.We further examine heterogeneity and identify underlying mechanisms from regional,market,management,and technological perspectives.The results indicate that carbon market policies act as a“double-edged sword”:they significantly reduce carbon emissions while diminishing firms’return on total assets.Regional analysis reveals stronger effects in economically advanced eastern provinces.On the market side,carbon trading tightens financing constraints and reduces liquidity;on the management side,it increases management expenses and boosts disclosures of internal control audits;and on the technological side,it drives higher research and development investment and patenting activity,reflecting intensified innovation under emissions pressure.These results provide a basis for future research on the long-term corporate impacts of carbon markets and offer policy recommendations for designing robust,equitable trading systems.
基金supported by the Nature Science Foundation of China (31961143015 To G.X.)Hainan Yazhou Bay Laboratory (B21HJ0215 To J.H)。
文摘Drought stress is a major environmental factor that limits the growth, development, and yield of rice(Oryza sativa L.). Histone deacetylases(HDACs) are involved in the regulation of drought stress responses. HDA704 is an RPD3/HDA1 class HDAC that mediates the deacetylation of H4K8(lysine 8of histone H4) for drought tolerance in rice. In this study, we show that plants overexpressing HDA704(HDA704-OE) are resistant to drought stress and sensitive to abscisic acid(ABA), whereas HDA704 knockout mutant(hda704) plants displayed decreased drought tolerance and ABA sensitivity.Transcriptome analysis revealed that HDA704 regulates the expression of ABA-related genes in response to drought stress. Moreover, HDA704 was recruited by a drought-resistant transcription factor,WAX SYNTHESIS REGULATORY 2(Os WR2), and co-regulated the expression of the ABA biosynthesis genes NINE-CIS-EPOXYCAROTENOID DIOXYGENASE 3(NCED3), NCED4, and NCED5 under drought stress. HDA704 also repressed the expression of ABA-INSENSITIVE 5(Os ABI5) and DWARF AND SMALL SEED 1(Os DSS1) by regulating H4K8ac levels in the promoter regions in response to polyethylene glycol 6000 treatment. In agreement, the loss of Os ABI5 function increased resistance to dehydration stress in rice. Our results demonstrate that HDA704 is a positive regulator of the drought stress response and offers avenues for improving drought resistance in rice.
基金supported by the 100 Talents Programme of Chinese Academy of Sciences(08BM031001)the Fok Ying Tung Education Foundation (114013) to H.M.the National Basic Research Program of China (2009CB320300)
文摘The "solidified liquid layer" model has been examined using a quartz crystal microbalance(QCM) with a polymeric matrix.The model is shown to give a reasonable explanation for the following experimental observations:(i) The opposite response of the QCM and surface plasmon resonance(SPR) for the activation process;(ii) the marked difference in the responses for IgG/anti-IgG interaction between QCM and SPR.Theoretical analysis and experimental results indicated that QCM is sensitive to the thickness change of the "solidified liquid layer" but not the mass of captured biomolecules(i.e.,the immobilized mass),implying caution must be taken in interpreting QCM results.
基金the National Natural Science Foundation of China(No.21801125)the Shenzhen Science and Technology Innovation Committee(No.JCYJ20180504165810828)+2 种基金the Guangdong High-Level Personnel of Special Support Program(No.2019TX05C157)the Guangdong Provincial Key Laboratory of Catalysis(No.2020B121201002)We thank SUSTech CRF and the Center for Computational Science and Engineering for the technical supports.
文摘The binding behaviors of three structurally similar and flexible cages to a series of quaternary ammonium ions have been systematically studied.The cage with phenyl sidewalls is new;moreover,its structure and conformational states have been characterized by NMR;2D NMR,and X-ray crystallography.The results reveal that the three cages show quite high binding affinities and selectivities to different vips.Enthalpy-entropy compensation was invoked to explain the different binding performance.Moreover,a six-component,high-fidelity self-sorting system was successfully constructed by using these cages and three vips.This suggests that conformationally flexible hosts may also achieve high binding affinities and selectivities,which is in contrast to the traditional point of view-only preorganized and rigid hosts are able to do so.This research advocates that conformational flexibility should also be seriously considered in host design.
基金supported by the National Natural Sci-ence Foundation of China(22072076 and 21773142)Taishan Schol-arship in Shandong Province(No.tsqn20161001)+1 种基金Fundamental Re-search Funds of Shandong University,Shandong Provincial Natural Sci-ence Foundation(ZR2020QE005)Young Doctor Cooperation Fund Project of Qilu University of Technology(Shandong Academy of Sci-ences)(2019BSHZ0018).
文摘Gold nanoparticles(Au NPs)have demonstrated great potential in chemical and biological sensing,catalysis,biomedicine,X-ray computed tomography,and other applications,owing to their unique properties.Au NPs with high-index facets have attracted more attention in the past decade owing to their superior electrocatalytic activity in fuel cells and enhanced performance in surface-enhanced Raman spectroscopy(SERS)applications.This review presents an overview of our achievements in the direct synthesis of Au NPs with controlled shapes in water using cationic surfactants.By deliberately adjusting the nature of the surfactant stabilizers,preformed Au NPs with simple shapes can be readily transformed into Au NPs with complicated shapes with controlled high-index facets by simple seeded growth.The high-index facets of the as-prepared Au NPs can be consistently correlated with their superior performance in the electrooxidation of methanol and ethanol and their enhanced SERS activity.
基金supported by the National Key Research and Development Program of China(2021YFA1100300)the National Natural Science Foundation of China(32288102,32370843 and 32025006)Part of the data analysis was performed on the High Performance Computing Platform of the Center for Life Sciences,Peking University。
文摘Human primed pluripotent stem cells are capable of generating all the embryonic lineages.However,their extraembryonic trophectoderm potentials are limited.It remains unclear how to expand their developmental potential to trophectoderm lineages.Here we show that transient treatment with a cocktail of small molecule epigenetic modulators imparts trophectoderm lineage potentials to human primed pluripotent stem cells while preserving their embryonic potential.These chemically treated cells can generate trophectoderm-like cells and downstream trophoblast stem cells,diverging into syncytiotrophoblast and extravillous trophoblast lineages.Transcriptomic and CUT&Tag analyses reveal that these induced cells share transcriptional profiles with in vivo trophectoderm and cytotrophoblast,and exhibit reduced H3K27me3 modification at gene loci specific to trophoblast lineages compared with primed pluripotent cells.Mechanistic exploration highlighted the critical roles of epigenetic modulators HDAC2,EZH1/2,and KDM5s in the activation of trophoblast lineage potential.Our findings demonstrate that transient epigenetic resetting activates unrestricted lineage potential in human primed pluripotent stem cells,and offer new mechanistic insights into human trophoblast lineage specification and in vitro models for studying placental development and related disorders.
