Flash Joule heating(FJH),as a high-efficiency and low-energy consumption technology for advanced materials synthesis,has shown significant potential in the synthesis of graphene and other functional carbon materials.B...Flash Joule heating(FJH),as a high-efficiency and low-energy consumption technology for advanced materials synthesis,has shown significant potential in the synthesis of graphene and other functional carbon materials.Based on the Joule effect,the solid carbon sources can be rapidly heated to ultra-high temperatures(>3000 K)through instantaneous high-energy current pulses during FJH,thus driving the rapid rearrangement and graphitization of carbon atoms.This technology demonstrates numerous advantages,such as solvent-and catalyst-free features,high energy conversion efficiency,and a short process cycle.In this review,we have systematically summarized the technology principle and equipment design for FJH,as well as its raw materials selection and pretreatment strategies.The research progress in the FJH synthesis of flash graphene,carbon nanotubes,graphene fibers,and anode hard carbon,as well as its by-products,is also presented.FJH can precisely optimize the microstructures of carbon materials(e.g.,interlayer spacing of turbostratic graphene,defect concentration,and heteroatom doping)by regulating its operation parameters like flash voltage and flash time,thereby enhancing their performances in various applications,such as composite reinforcement,metal-ion battery electrodes,supercapacitors,and electrocatalysts.However,this technology is still challenged by low process yield,macroscopic material uniformity,and green power supply system construction.More research efforts are also required to promote the transition of FJH from laboratory to industrial-scale applications,thus providing innovative solutions for advanced carbon materials manufacturing and waste management toward carbon neutrality.展开更多
MiR-219 and miR-338(miR-219/miR-338)are oligodendrocyte-specific microRNAs.The overexpression of these miRs in oligodendrocyte precursor cells promotes their differentiation and maturation into oligodendrocytes,which ...MiR-219 and miR-338(miR-219/miR-338)are oligodendrocyte-specific microRNAs.The overexpression of these miRs in oligodendrocyte precursor cells promotes their differentiation and maturation into oligodendrocytes,which may enhance axonal remyelination after nerve injuries in the central nervous system(CNS).As such,the delivery of miR-219/miR-338 to the CNS to promote oligodendrocyte precursor cell differentiation,maturation and myelination could be a promising approach for nerve repair.However,nerve injuries in the CNS also involve other cell types,such as microglia and astrocytes.Herein,we investigated the effects of miR-219/miR-338 treatment on microglia and astrocytes in vitro and in vivo.We found that miR-219/miR-338 diminished microglial expression of pro-inflammatory cytokines and suppressed astrocyte activation.In addition,we showed that miR-219/miR-338 enhanced oligodendrocyte precursor cell differentiation and maturation in a scratch assay paradigm that re-created a nerve injury condition in vitro.Collectively,our results suggest miR-219/miR-338 as a promising treatment for axonal remyelination in the CNS following nerve injuries.All experimental procedures were approved by the Institutional Animal Care and Use Committee(IACUC),Nanyang Technological University(approval No.A0309 and A0333)on April 27,2016 and October 8,2016.展开更多
Oceanic vertical mixing of the lower halocline water(LHW)in the Chukchi Borderland and Mendeleyev Ridge was studied based on in situ hydrographic and turbulent observations.The depth-averaged turbulent dissipation rat...Oceanic vertical mixing of the lower halocline water(LHW)in the Chukchi Borderland and Mendeleyev Ridge was studied based on in situ hydrographic and turbulent observations.The depth-averaged turbulent dissipation rate of LHW demonstrates a clear topographic dependence,with a mean value of 1.2×10^(-9) W/kg in the southwest of Canada Basin,1.5×10^(-9) W/kg in the Mendeleyev Abyssal Plain,2.4×10^(-9) W/kg on the Mendeleyev Ridge,and2.7×10^(-9) W/kg on the Chukchi Cap.Correspondingly,the mean depth-averaged vertical heat flux of the LHW is0.21 W/m^(2) in the southwest Canada Basin,0.30 W/m^(2) in the Mendeleyev Abyssal Plain,0.39 W/m^(2) on the Mendeleyev Ridge,and 0.46 W/m^(2) on the Chukchi Cap.However,in the presence of Pacific Winter Water,the upward heat released from Atlantic Water through the lower halocline can hardly contribute to the surface ocean.Further,the underlying mechanisms of diapycnal mixing in LHW—double diffusion and shear instability—was investigated.The mixing in LHW where double diffusion were observed is always relatively weaker,with corresponding dissipation rate ranging from 1.01×10^(-9) W/kg to 1.57×10^(-9) W/kg.The results also show a strong correlation between the depth-average dissipation rate and strain variance in the LHW,which indicates a close physical linkage between the turbulent mixing and internal wave activities.In addition,both surface wind forcing and semidiurnal tides significantly contribute to the turbulent mixing in the LHW.展开更多
慢性乙型肝炎病毒(Hepatitis B virus,HBV)感染是严重威胁人类生命健康的世界性公共卫生问题。基于现有抗HBV药物的治疗策略,仅能在极少部分患者中实现慢性乙肝的功能性治愈。发展更为有效的抗HBV药物,需要更加透彻全面地认识各个病毒...慢性乙型肝炎病毒(Hepatitis B virus,HBV)感染是严重威胁人类生命健康的世界性公共卫生问题。基于现有抗HBV药物的治疗策略,仅能在极少部分患者中实现慢性乙肝的功能性治愈。发展更为有效的抗HBV药物,需要更加透彻全面地认识各个病毒组分和关键宿主因子在HBV感染和复制生命周期中发挥的功能和机制,并在此基础上发现鉴定新的治疗靶点。支持HBV体外感染和复制的细胞模型,是研究HBV生活史的重要工具,并在治疗新靶点的发现和候选药物功效评估等研究工作中发挥关键作用。本文对支持HBV感染和复制细胞模型的新近研究进展进行梳理分析,并对这些模型的应用特点和局限性、新近研究进展和未来发展方向进行系统阐述和讨论。展开更多
A feasibility study on the mechanical design and walking operation of a Cassino biped locomotor is presented in this paper. The biped locomotor consists of two identical 3 degrees-of-freedom tripod leg mechanisms with...A feasibility study on the mechanical design and walking operation of a Cassino biped locomotor is presented in this paper. The biped locomotor consists of two identical 3 degrees-of-freedom tripod leg mechanisms with a parallel manipulator architecture. Planning of the biped walking gait is performed by coordinating the motions of the two leg mechanisms and waist. A three- dimensional model is elaborated in SolidWorks environ- ment in order to characterize a feasible mechanical design. Dynamic simulation is carried out in MSC.ADAMS environment with the aims of characterizing and evaluat- ing the dynamic walking design. Simulation results performance of the proposed show that the proposed biped locomotor with proper input motions of linear actuators performs practical and feasible walking on fiat surfaces with limited actuation and reaction forces between its feet and the ground. A preliminary prototype of the biped locomotor is built for the purpose of evaluating the operation performance of the biped walking gait of the proposed locomotor.展开更多
Spin-squeezed state is a many-body entangled state of great interest for precision measurements.Although the absolute sensitivity at the standard quantum limit is better for a larger atom number,the greater dominance ...Spin-squeezed state is a many-body entangled state of great interest for precision measurements.Although the absolute sensitivity at the standard quantum limit is better for a larger atom number,the greater dominance of classical noises over atom projection noise makes it harder to achieve spin squeezing.Here,we show both theoretically and experimentally that adiabatic pulse control of the pump field in state preparation is indispensable to sufficient noise suppression,which is the prerequisite for spin squeezing.This technique is generally applicable to spin-squeezing experiments involving a large ensemble and is thus of significance for quantum metrolog yapplications.展开更多
Intricate assembly of multiple molecular chromophores assisted by protein scaffolds is essential in tuning the optical absorption and energy transfer in the light-harvesting complexes of the photosynthetic systems in ...Intricate assembly of multiple molecular chromophores assisted by protein scaffolds is essential in tuning the optical absorption and energy transfer in the light-harvesting complexes of the photosynthetic systems in nature.However,it remains a challenge to achieve such structural complexity and functionality in synthetic polymer-chromophore systems.Here,we report a series of polyester-tethered pyrrolopyrrole cyanine derivatives and their colloidal nanoparticles dispersed in water,which show tunable J-or H-aggregation excitonic coupling and near-infrared fluorescence by precise control of the polymer chain lengths,composition,and temperature.Moreover,the optimal fluorescence or photothermal effect of the Jaggregate nanoparticles enables broad applications in fluorescence or photoacoustic bioimaging and phototherapy.展开更多
The discovery of fluorescent proteins has inspired a lot of interest to develop synthetic polymers with similar structures and functionalities.In this review article,we first give a brief introduction for the discover...The discovery of fluorescent proteins has inspired a lot of interest to develop synthetic polymers with similar structures and functionalities.In this review article,we first give a brief introduction for the discovery,the structural characteristics and optical properties of fluorescent proteins,using green fluorescent protein(GFP)as an example.In the body part of article,we summarize recent advances in molecular design,synthesis and processing of bioinspired fluorescent polymers with unique optical properties such as high fluorescence quantum yield and robust photostability.Several major approaches highlighted here include the recombination of organic chromophores and proteins,and synthesis of the bioinspired polymers containing a single fluorophore in each polymer chain.The optical properties and applications of some representative bioinspired fluorescent polymers in bioimaging,sensing and imaging-guided therapy are also elucidated.展开更多
基金supported by the National Natural Science Foundation of China(52276196)the Foundation of State Key Laboratory of Coal Combustion(FSKLCCA2508)the High-level Talent Foundation of Anhui Agricultural University(rc412307).
文摘Flash Joule heating(FJH),as a high-efficiency and low-energy consumption technology for advanced materials synthesis,has shown significant potential in the synthesis of graphene and other functional carbon materials.Based on the Joule effect,the solid carbon sources can be rapidly heated to ultra-high temperatures(>3000 K)through instantaneous high-energy current pulses during FJH,thus driving the rapid rearrangement and graphitization of carbon atoms.This technology demonstrates numerous advantages,such as solvent-and catalyst-free features,high energy conversion efficiency,and a short process cycle.In this review,we have systematically summarized the technology principle and equipment design for FJH,as well as its raw materials selection and pretreatment strategies.The research progress in the FJH synthesis of flash graphene,carbon nanotubes,graphene fibers,and anode hard carbon,as well as its by-products,is also presented.FJH can precisely optimize the microstructures of carbon materials(e.g.,interlayer spacing of turbostratic graphene,defect concentration,and heteroatom doping)by regulating its operation parameters like flash voltage and flash time,thereby enhancing their performances in various applications,such as composite reinforcement,metal-ion battery electrodes,supercapacitors,and electrocatalysts.However,this technology is still challenged by low process yield,macroscopic material uniformity,and green power supply system construction.More research efforts are also required to promote the transition of FJH from laboratory to industrial-scale applications,thus providing innovative solutions for advanced carbon materials manufacturing and waste management toward carbon neutrality.
基金supported by the Singapore National Research Foundation under its NMRC-CBRG grants(Project award number:NMRC/CBRG/0096/2015) and administered by the Singapore Ministry of Health’s National Medical Research Councilpartially supported by the MOE Academic Research Funding(AcRF) Tier 1 grant(RG148/14) and Tier 2 grant(MOE2015-T2-1-023)
文摘MiR-219 and miR-338(miR-219/miR-338)are oligodendrocyte-specific microRNAs.The overexpression of these miRs in oligodendrocyte precursor cells promotes their differentiation and maturation into oligodendrocytes,which may enhance axonal remyelination after nerve injuries in the central nervous system(CNS).As such,the delivery of miR-219/miR-338 to the CNS to promote oligodendrocyte precursor cell differentiation,maturation and myelination could be a promising approach for nerve repair.However,nerve injuries in the CNS also involve other cell types,such as microglia and astrocytes.Herein,we investigated the effects of miR-219/miR-338 treatment on microglia and astrocytes in vitro and in vivo.We found that miR-219/miR-338 diminished microglial expression of pro-inflammatory cytokines and suppressed astrocyte activation.In addition,we showed that miR-219/miR-338 enhanced oligodendrocyte precursor cell differentiation and maturation in a scratch assay paradigm that re-created a nerve injury condition in vitro.Collectively,our results suggest miR-219/miR-338 as a promising treatment for axonal remyelination in the CNS following nerve injuries.All experimental procedures were approved by the Institutional Animal Care and Use Committee(IACUC),Nanyang Technological University(approval No.A0309 and A0333)on April 27,2016 and October 8,2016.
基金The National Natural Science Foundation of China under contract No.42006037the Chinese Polar Environmental Comprehensive Investigation&Assessment Programs,Grant from the Scientific Research Fund of the Second Institute of Oceanography,MNR under contract No.JB904the National Key R&D Program of China under contract No.2019YFC1509102。
文摘Oceanic vertical mixing of the lower halocline water(LHW)in the Chukchi Borderland and Mendeleyev Ridge was studied based on in situ hydrographic and turbulent observations.The depth-averaged turbulent dissipation rate of LHW demonstrates a clear topographic dependence,with a mean value of 1.2×10^(-9) W/kg in the southwest of Canada Basin,1.5×10^(-9) W/kg in the Mendeleyev Abyssal Plain,2.4×10^(-9) W/kg on the Mendeleyev Ridge,and2.7×10^(-9) W/kg on the Chukchi Cap.Correspondingly,the mean depth-averaged vertical heat flux of the LHW is0.21 W/m^(2) in the southwest Canada Basin,0.30 W/m^(2) in the Mendeleyev Abyssal Plain,0.39 W/m^(2) on the Mendeleyev Ridge,and 0.46 W/m^(2) on the Chukchi Cap.However,in the presence of Pacific Winter Water,the upward heat released from Atlantic Water through the lower halocline can hardly contribute to the surface ocean.Further,the underlying mechanisms of diapycnal mixing in LHW—double diffusion and shear instability—was investigated.The mixing in LHW where double diffusion were observed is always relatively weaker,with corresponding dissipation rate ranging from 1.01×10^(-9) W/kg to 1.57×10^(-9) W/kg.The results also show a strong correlation between the depth-average dissipation rate and strain variance in the LHW,which indicates a close physical linkage between the turbulent mixing and internal wave activities.In addition,both surface wind forcing and semidiurnal tides significantly contribute to the turbulent mixing in the LHW.
文摘慢性乙型肝炎病毒(Hepatitis B virus,HBV)感染是严重威胁人类生命健康的世界性公共卫生问题。基于现有抗HBV药物的治疗策略,仅能在极少部分患者中实现慢性乙肝的功能性治愈。发展更为有效的抗HBV药物,需要更加透彻全面地认识各个病毒组分和关键宿主因子在HBV感染和复制生命周期中发挥的功能和机制,并在此基础上发现鉴定新的治疗靶点。支持HBV体外感染和复制的细胞模型,是研究HBV生活史的重要工具,并在治疗新靶点的发现和候选药物功效评估等研究工作中发挥关键作用。本文对支持HBV感染和复制细胞模型的新近研究进展进行梳理分析,并对这些模型的应用特点和局限性、新近研究进展和未来发展方向进行系统阐述和讨论。
文摘A feasibility study on the mechanical design and walking operation of a Cassino biped locomotor is presented in this paper. The biped locomotor consists of two identical 3 degrees-of-freedom tripod leg mechanisms with a parallel manipulator architecture. Planning of the biped walking gait is performed by coordinating the motions of the two leg mechanisms and waist. A three- dimensional model is elaborated in SolidWorks environ- ment in order to characterize a feasible mechanical design. Dynamic simulation is carried out in MSC.ADAMS environment with the aims of characterizing and evaluat- ing the dynamic walking design. Simulation results performance of the proposed show that the proposed biped locomotor with proper input motions of linear actuators performs practical and feasible walking on fiat surfaces with limited actuation and reaction forces between its feet and the ground. A preliminary prototype of the biped locomotor is built for the purpose of evaluating the operation performance of the biped walking gait of the proposed locomotor.
基金National Key Research and Development Program of China(2017YFA0304204,2016YFA0302000)National Natural Science Foundation of China(12027806,91636107)+2 种基金Royal Society Newton International Fellowship(NF170876)PCSIRT(IRT_17R70)1331KSC。
文摘Spin-squeezed state is a many-body entangled state of great interest for precision measurements.Although the absolute sensitivity at the standard quantum limit is better for a larger atom number,the greater dominance of classical noises over atom projection noise makes it harder to achieve spin squeezing.Here,we show both theoretically and experimentally that adiabatic pulse control of the pump field in state preparation is indispensable to sufficient noise suppression,which is the prerequisite for spin squeezing.This technique is generally applicable to spin-squeezing experiments involving a large ensemble and is thus of significance for quantum metrolog yapplications.
基金Chinese University of Hong Kong,Shenzhen,Grant/Award Number:UDF01001806Nanyang Technological University,Grant/Award Numbers:AcRFTier2(ARC36/13),AcRFTier1(2016-T1-001-2142018-T1-001-173)。
文摘Intricate assembly of multiple molecular chromophores assisted by protein scaffolds is essential in tuning the optical absorption and energy transfer in the light-harvesting complexes of the photosynthetic systems in nature.However,it remains a challenge to achieve such structural complexity and functionality in synthetic polymer-chromophore systems.Here,we report a series of polyester-tethered pyrrolopyrrole cyanine derivatives and their colloidal nanoparticles dispersed in water,which show tunable J-or H-aggregation excitonic coupling and near-infrared fluorescence by precise control of the polymer chain lengths,composition,and temperature.Moreover,the optimal fluorescence or photothermal effect of the Jaggregate nanoparticles enables broad applications in fluorescence or photoacoustic bioimaging and phototherapy.
基金We acknowledge the financial support by the University Development Fund-Research Start-up Fund(UDF01001806)from the Chinese University of Hong Kong,Shenzhen.H.X.and W.Z.thank the financial support of Ph.D.Scholarship from the Chinese University of Hong Kong,Shenzhen.
文摘The discovery of fluorescent proteins has inspired a lot of interest to develop synthetic polymers with similar structures and functionalities.In this review article,we first give a brief introduction for the discovery,the structural characteristics and optical properties of fluorescent proteins,using green fluorescent protein(GFP)as an example.In the body part of article,we summarize recent advances in molecular design,synthesis and processing of bioinspired fluorescent polymers with unique optical properties such as high fluorescence quantum yield and robust photostability.Several major approaches highlighted here include the recombination of organic chromophores and proteins,and synthesis of the bioinspired polymers containing a single fluorophore in each polymer chain.The optical properties and applications of some representative bioinspired fluorescent polymers in bioimaging,sensing and imaging-guided therapy are also elucidated.
