As an emerging multifunctional metal with the lowest melting point except for mercury,gallium combines a wide range of metallic and non-metallic elements to form advanced semiconductors critically important in cutting...As an emerging multifunctional metal with the lowest melting point except for mercury,gallium combines a wide range of metallic and non-metallic elements to form advanced semiconductors critically important in cutting-edge technologies.However,due to its low melting point and poor machinability,it is quite difficult to simultaneously characterize gallium’s elastic properties and damping characteristics using conventional methods,which is es-sential in designing and evaluating gallium-based structures.Therefore,developing effective methods to achieve accurate and efficient measurements of Young’s modulus and corresponding internal friction of gallium is of great significance.This letter studies simultaneous measurements of the variations in Young’s modulus and internal friction of gallium at varying temperatures by employing the modified piezoelectric ultrasonic composite oscil-lator technique.Combining the explicit theoretical formulas with the measured resonance and anti-resonance frequencies,it has been discovered that Young’s modulus undergoes an approximately linear decrease as the temperature rises,declining from 83.84 GPa at -70℃ to 79.37 GPa at 20℃.Moreover,like aluminum in the same Group ⅢA of the Periodic Table of Elements and exhibits a grain-boundary internal friction peak,gallium displays a longitudinal internal friction peak at approximately-12°C,with the peak value reaching 1.77×10^(-3).This basic research on gallium’s elastic properties and damping characteristics under low-temperature condi-tions will inspire further explorations of the mechanical properties of a diverse spectrum of low-melting-point functional materials and facilitate applications of gallium-based structures under complex conditions.展开更多
The integration of emerging technologies such as artificial intelligence and cloud computing is accelerating the development of intelligent and autonomous satellite systems.However,limitations in onboard sensing,compu...The integration of emerging technologies such as artificial intelligence and cloud computing is accelerating the development of intelligent and autonomous satellite systems.However,limitations in onboard sensing,computing,storage,and energy resources continue to constrain the intelligent functionalities of individual satellites.Currently,most studies focus on either satellite intelligence or satellite networking,while systematic studies on their integration remain scarce.To address this gap,this paper introduces the concept of an intelligent satellite cluster system,which leverages satellite networks to enable collaborative intelligence among satellites,thereby enhancing the overall system intelligence.After summarizing the typical use cases of the intelligent satellite cluster system,we analyze the corresponding demands on network capabilities.Based on these demands,we propose the concept of the Internet of satellites(IoS)tailored to support the intelligent satellite cluster system.Specifically,we design both the logical and physical architectures of IoS and elaborate on its key enabling technologies.Finally,we present the research progress and outcomes achieved by our team on these core technologies,and discuss the challenges that remain.This paper aims to build consensus around intelligent and connected satellite technologies,promote innovation and standardization,and enhance the intelligent service capabilities of future large-scale satellite systems.展开更多
Dam discharges over spillways are the main reason for the gas-supersaturated water generated in rivers.Local aquatic organisms,especially fish,readily develop gas bubble disease(GBD) in a river with total dissolved ga...Dam discharges over spillways are the main reason for the gas-supersaturated water generated in rivers.Local aquatic organisms,especially fish,readily develop gas bubble disease(GBD) in a river with total dissolved gas supersaturation(TDGS).Sometimes,fish will die after a specific exposure period,which negatively affects the biological equilibrium.In this study,the influence of TDGS on silver carp was explored.Silver carp were exposed to gas-supersaturated water with TDGS levels of 140%,135%,130%,125%,120%,and 110%to test the impact of TDGS.Some silver carp died when the TDGS level was 120%or higher,and all the silver carp exposed to a TDGS level of 140%died within10 h.In comparison with the Chinese sucker,Prenant's schizothoracin,and rock carp,silver carp seem less sensitive to TDGS.In addition,we tested the catalase(CAT) activity in the muscles and gills of silver carp after they were exposed to gas-supersaturated water with a TDGS level of140%.The CAT activity changed with time;it increased first and then decreased until it was lower than the initial CAT activity.The results of this study can provide basic data for developing a standard for environmental evaluation.展开更多
Doublet luminescence from hybrid metal trihalide perovskite semiconductors is observed along with materials processing when high-quality single crystals are obtainable.Yet,the underlying physical mechanism remains poo...Doublet luminescence from hybrid metal trihalide perovskite semiconductors is observed along with materials processing when high-quality single crystals are obtainable.Yet,the underlying physical mechanism remains poorly understood.Here,we report controllable solution-processed crystallization that affords high-quality CH3 NH3 PbBr3 single crystals with atomically flat pristine surfaces.Front-face photoluminescence(PL)shows doublet luminescence components with variable relative intensities depending on the crystal surface conditions.We further find that the low-energy PL component with asymmetric spectral line-shape becomes predominant when the atomically flat crystal surfaces are passivated in the ion-abundant saturated solutions,while poor-quality single crystal with visually rough surface only gives the high-energy PL with symmetric line-shape.The asymmetric spectral line-shape of the low-energy PL matches perfectly with the simulated bandedge emission.Therefore,the low-energy PL component is attributable to the intrinsic bandedge emission from the crystal bulk while the high-energy one to surface-specific emission.Elliott fitting to the absorption data and multi-exponential fitting to the time-resolved photoluminescence traces jointly indicate the coexistence of excitons and electron-hole plasmas in optically excited CH_(3)NH_(3)PbBr_(3)single crystals,thereby catching the physical merit that leads to the occurrence of doublet luminescence.展开更多
Osteosarcoma(OS)is the most frequent primary bone sarcomas with high recurrence and poor prognosis.Emerging evidence indicates that membraneless organelles stress granules(SGs),whose assemblies are driven by scaffold ...Osteosarcoma(OS)is the most frequent primary bone sarcomas with high recurrence and poor prognosis.Emerging evidence indicates that membraneless organelles stress granules(SGs),whose assemblies are driven by scaffold protein G3BP1,are extensively involved in tumor,especially in OS.However,how SGs behave and communicate with organelles,particularly nucleoli and mitochondria,during drug challenges remain unknown.This study revealed that chemotherapeutic drugs activated the cysteine protease asparagine endopeptidase(AEP)to specifically cleave the SG core protein G3BP1 at N258/N309 in OS and malignant glioma.tG3BP1-Ns modulated SG dynamics by competitively binding to full-length G3BP1.Strikingly,tG3BP1-Cs,containing a conserved RNA recognition motif CCUBSCUS,sequestered mRNAs of ribosomal proteins and oxidative phosphorylation genes in the nucleoli and mitochondria to repress translation and oxidative stress.Moreover,the inhibition of AEP promoted the tumor-suppressing effect of chemotherapeutic drugs,whereas AEP-cleaved G3BP1 rescue reversed the effect in both OS and glioma models.Cancerous tissues exhibited high levels of AEP and G3BP1 truncations,which were strongly associated with poor prognosis.展开更多
Cold stress widely impairs the quality and yield of tea plants. The miR164 family and its target NAC transcription factor have been identified as crucial regulators in response to cold stress. However, the role of miR...Cold stress widely impairs the quality and yield of tea plants. The miR164 family and its target NAC transcription factor have been identified as crucial regulators in response to cold stress. However, the role of miR164 and CsNAC in cold tolerance in tea plants was little understood. In our study, the expression level of CsMIR164a was significantly reduced under cold stress and significantly and negatively correlated with that of CsNAC1.5' RACE and GUS histochemical assays showed that CsNAC1 was cleaved by CsMIR164a. The CsMIR164a-silenced tea leaves promoted the expression levels of CsNAC1 and CsCBFs and exhibited greater cold tolerance. Also, the overexpression of CsNAC1 enhanced cold tolerance in transgenic Arabidopsis plants by promoting the expression levels of AtCBFs. In contrast, the heterologous overexpression of CsMIR164a in Arabidopsis decreased the expression level of AtNACs and AtCBFs and thus impaired cold tolerance. Additionally, silencing of CsNAC1 impaired the expression levels of CsCBFs, resulting in greater cold sensitivity in tea leaves. Our present study demonstrated that the miR164a-CsNAC1 module may play a negative role in the cold tolerance of tea plants via the CsCBF-dependent pathway.展开更多
The cell cycle is a tightly coupled series of events that enable cells to grow and proliferate.Cyclin-dependent kinases(CDKs)play crucial roles in the cell cycle by enabling cells to transition between different phase...The cell cycle is a tightly coupled series of events that enable cells to grow and proliferate.Cyclin-dependent kinases(CDKs)play crucial roles in the cell cycle by enabling cells to transition between different phases when they are activated.Cell cycle proteins enhance the activity of CDKs,while natural CDK inhibitors(CDKIs)suppress them.The cell cycle continues in cycles under normal conditions,but when conditions change,cells halt or terminate the cell cycle.Tumors are tissues that grow out of control,and the mechanisms of various types of tumors are different;however,almost all tumor cells share several common characteristics,including proliferation,prevention of apoptosis and genomic instability.Cellular division is essential in the progression of cancer.A key characteristic of cancer is the uncontrolled growth of tumor cells,which is due to the erratic behavior of several proteins during the cell cycle.Therefore,cell cycle regulators are considered attractive targets for the treatment of cancer.The present analysis highlights proteins that play a direct role in controlling the tumor cell cycle,such as CDKs,and provides a brief overview of checkpoint kinases.The present review also discusses how cell cycle proteins contribute to cancer and describes some of the antitumor drugs that are being researched.展开更多
基金financially supported by the National Key R&D Program of China(Grant No.2023YFF0716800)the National Natural Science Foundation of China(Grant No.12074160)the Natural Science Foundation of Liaoning Province of China(Grant No.2024-MS-181).
文摘As an emerging multifunctional metal with the lowest melting point except for mercury,gallium combines a wide range of metallic and non-metallic elements to form advanced semiconductors critically important in cutting-edge technologies.However,due to its low melting point and poor machinability,it is quite difficult to simultaneously characterize gallium’s elastic properties and damping characteristics using conventional methods,which is es-sential in designing and evaluating gallium-based structures.Therefore,developing effective methods to achieve accurate and efficient measurements of Young’s modulus and corresponding internal friction of gallium is of great significance.This letter studies simultaneous measurements of the variations in Young’s modulus and internal friction of gallium at varying temperatures by employing the modified piezoelectric ultrasonic composite oscil-lator technique.Combining the explicit theoretical formulas with the measured resonance and anti-resonance frequencies,it has been discovered that Young’s modulus undergoes an approximately linear decrease as the temperature rises,declining from 83.84 GPa at -70℃ to 79.37 GPa at 20℃.Moreover,like aluminum in the same Group ⅢA of the Periodic Table of Elements and exhibits a grain-boundary internal friction peak,gallium displays a longitudinal internal friction peak at approximately-12°C,with the peak value reaching 1.77×10^(-3).This basic research on gallium’s elastic properties and damping characteristics under low-temperature condi-tions will inspire further explorations of the mechanical properties of a diverse spectrum of low-melting-point functional materials and facilitate applications of gallium-based structures under complex conditions.
基金supported in part by National Natural Science Foundation of China(62401612)in part by Beijing Nova Program of China(20230484258).
文摘The integration of emerging technologies such as artificial intelligence and cloud computing is accelerating the development of intelligent and autonomous satellite systems.However,limitations in onboard sensing,computing,storage,and energy resources continue to constrain the intelligent functionalities of individual satellites.Currently,most studies focus on either satellite intelligence or satellite networking,while systematic studies on their integration remain scarce.To address this gap,this paper introduces the concept of an intelligent satellite cluster system,which leverages satellite networks to enable collaborative intelligence among satellites,thereby enhancing the overall system intelligence.After summarizing the typical use cases of the intelligent satellite cluster system,we analyze the corresponding demands on network capabilities.Based on these demands,we propose the concept of the Internet of satellites(IoS)tailored to support the intelligent satellite cluster system.Specifically,we design both the logical and physical architectures of IoS and elaborate on its key enabling technologies.Finally,we present the research progress and outcomes achieved by our team on these core technologies,and discuss the challenges that remain.This paper aims to build consensus around intelligent and connected satellite technologies,promote innovation and standardization,and enhance the intelligent service capabilities of future large-scale satellite systems.
基金supported by the National Natural Science Foundation of China(Grant No.51379136)
文摘Dam discharges over spillways are the main reason for the gas-supersaturated water generated in rivers.Local aquatic organisms,especially fish,readily develop gas bubble disease(GBD) in a river with total dissolved gas supersaturation(TDGS).Sometimes,fish will die after a specific exposure period,which negatively affects the biological equilibrium.In this study,the influence of TDGS on silver carp was explored.Silver carp were exposed to gas-supersaturated water with TDGS levels of 140%,135%,130%,125%,120%,and 110%to test the impact of TDGS.Some silver carp died when the TDGS level was 120%or higher,and all the silver carp exposed to a TDGS level of 140%died within10 h.In comparison with the Chinese sucker,Prenant's schizothoracin,and rock carp,silver carp seem less sensitive to TDGS.In addition,we tested the catalase(CAT) activity in the muscles and gills of silver carp after they were exposed to gas-supersaturated water with a TDGS level of140%.The CAT activity changed with time;it increased first and then decreased until it was lower than the initial CAT activity.The results of this study can provide basic data for developing a standard for environmental evaluation.
基金Project supported by the National Natural Science Foundation of China(Grant No.51872038)。
文摘Doublet luminescence from hybrid metal trihalide perovskite semiconductors is observed along with materials processing when high-quality single crystals are obtainable.Yet,the underlying physical mechanism remains poorly understood.Here,we report controllable solution-processed crystallization that affords high-quality CH3 NH3 PbBr3 single crystals with atomically flat pristine surfaces.Front-face photoluminescence(PL)shows doublet luminescence components with variable relative intensities depending on the crystal surface conditions.We further find that the low-energy PL component with asymmetric spectral line-shape becomes predominant when the atomically flat crystal surfaces are passivated in the ion-abundant saturated solutions,while poor-quality single crystal with visually rough surface only gives the high-energy PL with symmetric line-shape.The asymmetric spectral line-shape of the low-energy PL matches perfectly with the simulated bandedge emission.Therefore,the low-energy PL component is attributable to the intrinsic bandedge emission from the crystal bulk while the high-energy one to surface-specific emission.Elliott fitting to the absorption data and multi-exponential fitting to the time-resolved photoluminescence traces jointly indicate the coexistence of excitons and electron-hole plasmas in optically excited CH_(3)NH_(3)PbBr_(3)single crystals,thereby catching the physical merit that leads to the occurrence of doublet luminescence.
基金supported by the National Key R&D Program of China(grant number 2023ZD0502206,2024YFB3213200,Topic No.2024YFB3213204)National Natural Science Foundation of China(nos.82273278,82373514,82373202,82272728,82002630,81772654)+5 种基金the National Key Research and Development Program of China(grant number 2022YFC2404602)Shanghai Hospital Development Center Foundation(grant number SHDC12023108)Scientific and Technological Innovation Action Plan of Shanghai Science and Technology Committee(grant number 22Y31900103)Beijing Science and Technology Innovation Medical Development Foundation(grant number KC2021-JX-0170-9)the Shanghai Association for Science and Technology(nos.201409003000,201409002400,20YF1426200)Shanghai Science and Technology Innovation Action Plan(grant number 23Y41900100).
文摘Osteosarcoma(OS)is the most frequent primary bone sarcomas with high recurrence and poor prognosis.Emerging evidence indicates that membraneless organelles stress granules(SGs),whose assemblies are driven by scaffold protein G3BP1,are extensively involved in tumor,especially in OS.However,how SGs behave and communicate with organelles,particularly nucleoli and mitochondria,during drug challenges remain unknown.This study revealed that chemotherapeutic drugs activated the cysteine protease asparagine endopeptidase(AEP)to specifically cleave the SG core protein G3BP1 at N258/N309 in OS and malignant glioma.tG3BP1-Ns modulated SG dynamics by competitively binding to full-length G3BP1.Strikingly,tG3BP1-Cs,containing a conserved RNA recognition motif CCUBSCUS,sequestered mRNAs of ribosomal proteins and oxidative phosphorylation genes in the nucleoli and mitochondria to repress translation and oxidative stress.Moreover,the inhibition of AEP promoted the tumor-suppressing effect of chemotherapeutic drugs,whereas AEP-cleaved G3BP1 rescue reversed the effect in both OS and glioma models.Cancerous tissues exhibited high levels of AEP and G3BP1 truncations,which were strongly associated with poor prognosis.
基金supported by the Anhui University Collaborative Innovation Project, China (GXXT-2020080)the Scientific Research Project of Anhui Provincial Colleges and Universities, China (2023AH040136)。
文摘Cold stress widely impairs the quality and yield of tea plants. The miR164 family and its target NAC transcription factor have been identified as crucial regulators in response to cold stress. However, the role of miR164 and CsNAC in cold tolerance in tea plants was little understood. In our study, the expression level of CsMIR164a was significantly reduced under cold stress and significantly and negatively correlated with that of CsNAC1.5' RACE and GUS histochemical assays showed that CsNAC1 was cleaved by CsMIR164a. The CsMIR164a-silenced tea leaves promoted the expression levels of CsNAC1 and CsCBFs and exhibited greater cold tolerance. Also, the overexpression of CsNAC1 enhanced cold tolerance in transgenic Arabidopsis plants by promoting the expression levels of AtCBFs. In contrast, the heterologous overexpression of CsMIR164a in Arabidopsis decreased the expression level of AtNACs and AtCBFs and thus impaired cold tolerance. Additionally, silencing of CsNAC1 impaired the expression levels of CsCBFs, resulting in greater cold sensitivity in tea leaves. Our present study demonstrated that the miR164a-CsNAC1 module may play a negative role in the cold tolerance of tea plants via the CsCBF-dependent pathway.
文摘The cell cycle is a tightly coupled series of events that enable cells to grow and proliferate.Cyclin-dependent kinases(CDKs)play crucial roles in the cell cycle by enabling cells to transition between different phases when they are activated.Cell cycle proteins enhance the activity of CDKs,while natural CDK inhibitors(CDKIs)suppress them.The cell cycle continues in cycles under normal conditions,but when conditions change,cells halt or terminate the cell cycle.Tumors are tissues that grow out of control,and the mechanisms of various types of tumors are different;however,almost all tumor cells share several common characteristics,including proliferation,prevention of apoptosis and genomic instability.Cellular division is essential in the progression of cancer.A key characteristic of cancer is the uncontrolled growth of tumor cells,which is due to the erratic behavior of several proteins during the cell cycle.Therefore,cell cycle regulators are considered attractive targets for the treatment of cancer.The present analysis highlights proteins that play a direct role in controlling the tumor cell cycle,such as CDKs,and provides a brief overview of checkpoint kinases.The present review also discusses how cell cycle proteins contribute to cancer and describes some of the antitumor drugs that are being researched.
