Hydrostatic pressure provides an efficient way to tune and optimize the properties of solid materials without chang-ing their composition.In this work,we investigate the electronic,optical,and mechanical properties of...Hydrostatic pressure provides an efficient way to tune and optimize the properties of solid materials without chang-ing their composition.In this work,we investigate the electronic,optical,and mechanical properties of antiperovskite X_(3)NP(X^(2+)=Ca,Mg)upon compression by first-principles calculations.Our results reveal that the system is anisotropic,and the lat-tice constant a of X_(3)NP exhibits the fastest rate of decrease upon compression among the three directions,which is different from the typical Pnma phase of halide and chalcogenide perovskites.Meanwhile,Ca_(3)NP has higher compressibility than Mg_(3)NP due to its small bulk modulus.The electronic and optical properties of Mg_(3)NP show small fluctuations upon compression,but those of Ca_(3)NP are more sensitive to pressure due to its higher compressibility and lower unoccupied 3d orbital energy.For example,the band gap,lattice dielectric constant,and exciton binding energy of Ca_(3)NP decrease rapidly as the pressure increases.In addition,the increase in pressure significantly improves the optical absorption and theoretical conversion effi-ciency of Ca_(3)NP.Finally,the mechanical properties of X_(3)NP are also increased upon compression due to the reduction in bond length,while inducing a brittle-to-ductile transition.Our research provides theoretical guidance and insights for future experi-mental tuning of the physical properties of antiperovskite semiconductors by pressure.展开更多
In recent years,neonicotinoids(NEOs)and organophosphate esters(OPEs)have been widely used as substitutes for traditional pesticides and brominated fame-retardants,respectively.Previous studies have shown that those co...In recent years,neonicotinoids(NEOs)and organophosphate esters(OPEs)have been widely used as substitutes for traditional pesticides and brominated fame-retardants,respectively.Previous studies have shown that those compounds can be frequently detected in environmental and human samples,are able to penetrate the placental barrier,and are toxic to animals.Thus,it is reasonable to speculate that NEOs and OPEs may have potential adverse effects in humans,especially during development.We employed a human embryonic stem cell differentiation-and liver S9 fraction metabolism-based fast screening model to assess the potential embryonic toxicity of those two types of chemicals.We show that four NEO and five OPE prototypes targeted mostly ectoderm specification,as neural ectoderm and neural crest genes were down-regulated,and surface ectoderm and placode markers up-regulated.Human liver S9 fraction's treatment could generally reduce the effects of the chemicals,except in a few specific instances,indicating the liver may detoxify NEOs and OPEs.Our findings suggest that NEOs and OPEs interfere with human early embryonic development.展开更多
Genome editing through adeno-associated viral(AAV) vectors is a promising gene therapy strategy for various diseases,especially genetic disorders. However, homologous recombination(HR) efficiency is extremely low in a...Genome editing through adeno-associated viral(AAV) vectors is a promising gene therapy strategy for various diseases,especially genetic disorders. However, homologous recombination(HR) efficiency is extremely low in adult animal models. We assumed that increasing AAV transduction efficiency could increase genome editing activity, especially HR efficiency, for in vivo gene therapy. Firstly, a mouse phenylketonuria(PKU) model carrying a pathogenic R408W mutation in phenylalanine hydroxylase(Pah) was generated. Through co-delivery of the general AAV receptor(AAVR), we found that AAVR could dramatically increase AAV transduction efficiency in vitro and in vivo. Furthermore, co-delivery of SaCas9/sgRNA/donor templates with AAVR via AAV8 vectors increased indel rate over 2-fold and HR rate over 15-fold for the correction of the single mutation in Pah;mice. Moreover, AAVR co-injection successfully increased the site-specific insertion rate of a 1.4 kb Pah cDNA by 11-fold, bringing the HR rate up to 7.3% without detectable global off-target effects. Insertion of Pah cDNA significantly decreased the Phe level and ameliorated PKU symptoms. This study demonstrates a novel strategy to dramatically increase AAV transduction which substantially enhanced in vivo genome editing efficiency in adult animal models, showing clinical potential for both conventional and genome editing-based gene therapy.展开更多
We present the perfect light absorption of monolayer molybdenum disulfide(MoS_(2))in a dielectric multilayer system with two different Bragg mirrors.The results show that the strong absorption of visible light in mono...We present the perfect light absorption of monolayer molybdenum disulfide(MoS_(2))in a dielectric multilayer system with two different Bragg mirrors.The results show that the strong absorption of visible light in monolayer MoS_(2) is attributed to the formation of optical Tamm states(OTSs)between two Bragg mirrors.The MoS_(2) absorption spectrum is dependent on the layer thickness of Bragg mirrors,incident angle of light,and the period numbers of Bragg mirrors.Especially,the nearly perfect light absorption(99.4%)of monolayer MoS_(2) can be achieved by choosing proper period numbers,which is well analyzed by the temporal coupled-mode theory.展开更多
Background Left ventricular filling pressure(LVFP)is an important early indicator of heart failure that is more prevalent in Caucasians than Chinese.Exercise-induced change in LVFP may provide more incremental informa...Background Left ventricular filling pressure(LVFP)is an important early indicator of heart failure that is more prevalent in Caucasians than Chinese.Exercise-induced change in LVFP may provide more incremental information to assess dias-tolic function.But it was unknown whether there was difference in LVFP following acute exercise between Caucasians and Chinese.Purpose The purpose of this study was to investigate the change of LVFP following an acute 45-min aerobic exercise in healthy Caucasian and Chinese individuals.Methods Sixty participants(30 Caucasians and 30 Chinese,half was male,respectively)performed an acute bout of aero-bic exercise at 70%of heart rate reserve.Hemodynamics,Left ventricle(LV)morphology and function parameters were measured at baseline,then at 30-min and 60-min post-exercise.Results There was a similar LV ejection fraction,LV fraction shorten,lateral E/eʹand lateral eʹbetween Chinese and Caucasians at baseline.There was a significant race-by-time interaction in lateral E/eʹand lateral eʹbetween Chinese and Caucasians from pre-exercise to 30 min and 60 min after acute aerobic exercise.TheΔE/eʹwas significant correlated with baseline systolic blood pressure.Conclusion The change of LVFP was different between Chinese and Caucasians following acute aerobic exercise.The racial differences may be primarily caused by the changes of LV relaxation following exercise,baseline systolic blood pressure may also contribute to the differences.展开更多
In this work, it has been demonstrated that in order to fully understand the terahertz(THz) pulse generation process during femtosecond laser filamentation, the interaction between THz wave and air plasma has to be ta...In this work, it has been demonstrated that in order to fully understand the terahertz(THz) pulse generation process during femtosecond laser filamentation, the interaction between THz wave and air plasma has to be taken into account. This interaction is mainly associated with the spatial confinement of the THz pulse by the plasma column, which could be described by the one-dimensional negative dielectric(1DND) waveguide model. By combining the 1 DND model with the conventional four-wave mixing(4WM) and photocurrent(PC) models,the variation of THz spectral amplitude and width obtained in experiments could be better understood. Finally, a three-step procedure, with 1DND bridging 4WM and PC processes, has been established for the first time to describe the underlying mechanism of THz radiation from plasma sources.展开更多
Xyloketals,a new type of antioxidants from a marine mangrove fungus,have potential pharmacological properties.In this paper,the radical-scavenging activities of a series of synthetic xyloketals and related chromanes t...Xyloketals,a new type of antioxidants from a marine mangrove fungus,have potential pharmacological properties.In this paper,the radical-scavenging activities of a series of synthetic xyloketals and related chromanes toward 2,2-diphenyl-1-picrylhydrazyl(DPPH)and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS)were evaluated by absorption spectrometry.One of the compounds(compound 10)displayed significant antioxidative action against DPPH and ABTS.A structure-activity analysis showed that the reactive sites on these compounds correlated with a hydroxygroup and also with ketal or aromatic H substituents.Based in part on a density functional theory(DFT)calculation of compound 10,the antioxidant mechanism of this chromane was deduced as a possible radical-scavenging mechanism by a sequential proton loss electron-transfer(SPLET)process.展开更多
Thermal conductivity of two-dimensional(2D)materials has gained prominence due to the attractive applications in thermal management and thermoelectric devices.In this work,we present a new member of bilayer 2D boron a...Thermal conductivity of two-dimensional(2D)materials has gained prominence due to the attractive applications in thermal management and thermoelectric devices.In this work,we present a new member of bilayer 2D boron allotropes,denoted as bilayerβ12 borophene,and study the thermal transport properties by solving phonon Boltzmann transport equation based on density functional theory.Based on quantitative chemical bonding analysis,we identify large degrees of covalent bonding of the interlayer interaction.In comparison to its monolayer counterpart,the bilayer exhibits much higher in-plane thermal conductivity despite the lower phonon group velocity and buckling structure,inferring a new physical mechanism.The thermal conductivity(κ)of bilayerβ_(12)borophene at 300 K is 140.5(86.3)W·m^(-1)·K^(-1)along armchair(zigzag)direction,andκ_(armchair)is about 52.7%higher than that of monolayerβ12 borophene.The abnormal enhancement is attributed to the suppressed phonon scattering possibility and elongation of phonon lifetime.More interesting,after forming bilayerβ12 borophene through interlayer covalent bonding,the dominated phonon branch to thermal conductivity changes to transverse acoustic phonons from out-of-plane flexural acoustic(ZA)phonons in the monolayer borophene.Our study elucidates the rich thermal transport characteristics in bilayer covalently bonded 2D materials,and injects fresh insights into the phonon engineering of 2D borophene relevant for emergent thermal management applications.展开更多
基金supported by the Science and Technology Research Program of Chongqing Municipal Education Commission (Grant No. KJQN202100626)the Science and Technology Research Program of Chongqing Municipal Education Commission (Grant No. KJQN202200619)+3 种基金supported by Beijing Institute of Technology Research Fund Program for Young Scholars (Grant No. XSQD-202222008)the support from the National Natural Science Foundation of China (Grant No. 12204081)the Natural Science Foundation of Chongqing (Grant No. 2022NSCQ-MSX2540)supported by TianHe Qingsuo Project-spec ial fund project
文摘Hydrostatic pressure provides an efficient way to tune and optimize the properties of solid materials without chang-ing their composition.In this work,we investigate the electronic,optical,and mechanical properties of antiperovskite X_(3)NP(X^(2+)=Ca,Mg)upon compression by first-principles calculations.Our results reveal that the system is anisotropic,and the lat-tice constant a of X_(3)NP exhibits the fastest rate of decrease upon compression among the three directions,which is different from the typical Pnma phase of halide and chalcogenide perovskites.Meanwhile,Ca_(3)NP has higher compressibility than Mg_(3)NP due to its small bulk modulus.The electronic and optical properties of Mg_(3)NP show small fluctuations upon compression,but those of Ca_(3)NP are more sensitive to pressure due to its higher compressibility and lower unoccupied 3d orbital energy.For example,the band gap,lattice dielectric constant,and exciton binding energy of Ca_(3)NP decrease rapidly as the pressure increases.In addition,the increase in pressure significantly improves the optical absorption and theoretical conversion effi-ciency of Ca_(3)NP.Finally,the mechanical properties of X_(3)NP are also increased upon compression due to the reduction in bond length,while inducing a brittle-to-ductile transition.Our research provides theoretical guidance and insights for future experi-mental tuning of the physical properties of antiperovskite semiconductors by pressure.
基金supported by the Ministry of Science and Technology of the People’s Republic of China (No.2020YFA0907500)the National Natural Science Foundation of China (Nos.22150710514,22021003,and 22106174)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences (No.XDPB200202)the Postdoc Science Foundation of China (No.2021M693322)。
文摘In recent years,neonicotinoids(NEOs)and organophosphate esters(OPEs)have been widely used as substitutes for traditional pesticides and brominated fame-retardants,respectively.Previous studies have shown that those compounds can be frequently detected in environmental and human samples,are able to penetrate the placental barrier,and are toxic to animals.Thus,it is reasonable to speculate that NEOs and OPEs may have potential adverse effects in humans,especially during development.We employed a human embryonic stem cell differentiation-and liver S9 fraction metabolism-based fast screening model to assess the potential embryonic toxicity of those two types of chemicals.We show that four NEO and five OPE prototypes targeted mostly ectoderm specification,as neural ectoderm and neural crest genes were down-regulated,and surface ectoderm and placode markers up-regulated.Human liver S9 fraction's treatment could generally reduce the effects of the chemicals,except in a few specific instances,indicating the liver may detoxify NEOs and OPEs.Our findings suggest that NEOs and OPEs interfere with human early embryonic development.
基金partially supported by grants from the National Key R&D Program of China (2019YFA0110802)the National Natural Science Foundation of China (81670470 and 81873685)+2 种基金grants from the Shanghai Municipal Commission for Science and Technology (18411953500 and 20140900201)a grant from the Innovation Program of Shanghai Municipal Education Commission (2019-01-07-00-05-E00054)the Fundamental Research Funds for the Central Universities
文摘Genome editing through adeno-associated viral(AAV) vectors is a promising gene therapy strategy for various diseases,especially genetic disorders. However, homologous recombination(HR) efficiency is extremely low in adult animal models. We assumed that increasing AAV transduction efficiency could increase genome editing activity, especially HR efficiency, for in vivo gene therapy. Firstly, a mouse phenylketonuria(PKU) model carrying a pathogenic R408W mutation in phenylalanine hydroxylase(Pah) was generated. Through co-delivery of the general AAV receptor(AAVR), we found that AAVR could dramatically increase AAV transduction efficiency in vitro and in vivo. Furthermore, co-delivery of SaCas9/sgRNA/donor templates with AAVR via AAV8 vectors increased indel rate over 2-fold and HR rate over 15-fold for the correction of the single mutation in Pah;mice. Moreover, AAVR co-injection successfully increased the site-specific insertion rate of a 1.4 kb Pah cDNA by 11-fold, bringing the HR rate up to 7.3% without detectable global off-target effects. Insertion of Pah cDNA significantly decreased the Phe level and ameliorated PKU symptoms. This study demonstrates a novel strategy to dramatically increase AAV transduction which substantially enhanced in vivo genome editing efficiency in adult animal models, showing clinical potential for both conventional and genome editing-based gene therapy.
基金supported by the National Key R&D Program of China(No.2017YFA0303800)the National Natural Science Foundation of China(Nos.11774290,11974283,61705186,and 11634010)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2020JM-130)。
文摘We present the perfect light absorption of monolayer molybdenum disulfide(MoS_(2))in a dielectric multilayer system with two different Bragg mirrors.The results show that the strong absorption of visible light in monolayer MoS_(2) is attributed to the formation of optical Tamm states(OTSs)between two Bragg mirrors.The MoS_(2) absorption spectrum is dependent on the layer thickness of Bragg mirrors,incident angle of light,and the period numbers of Bragg mirrors.Especially,the nearly perfect light absorption(99.4%)of monolayer MoS_(2) can be achieved by choosing proper period numbers,which is well analyzed by the temporal coupled-mode theory.
基金This study was funded by the National Institute of Health of USA(1R01HL093249-01A1)National Education Science Planning Program of China(BLA170225).
文摘Background Left ventricular filling pressure(LVFP)is an important early indicator of heart failure that is more prevalent in Caucasians than Chinese.Exercise-induced change in LVFP may provide more incremental information to assess dias-tolic function.But it was unknown whether there was difference in LVFP following acute exercise between Caucasians and Chinese.Purpose The purpose of this study was to investigate the change of LVFP following an acute 45-min aerobic exercise in healthy Caucasian and Chinese individuals.Methods Sixty participants(30 Caucasians and 30 Chinese,half was male,respectively)performed an acute bout of aero-bic exercise at 70%of heart rate reserve.Hemodynamics,Left ventricle(LV)morphology and function parameters were measured at baseline,then at 30-min and 60-min post-exercise.Results There was a similar LV ejection fraction,LV fraction shorten,lateral E/eʹand lateral eʹbetween Chinese and Caucasians at baseline.There was a significant race-by-time interaction in lateral E/eʹand lateral eʹbetween Chinese and Caucasians from pre-exercise to 30 min and 60 min after acute aerobic exercise.TheΔE/eʹwas significant correlated with baseline systolic blood pressure.Conclusion The change of LVFP was different between Chinese and Caucasians following acute aerobic exercise.The racial differences may be primarily caused by the changes of LV relaxation following exercise,baseline systolic blood pressure may also contribute to the differences.
基金National Key R&D Program of China(2017YFC0821300)National Natural Science Foundation of China(NSFC)(11704252,11574160,61722111)+6 种基金National Program on Key Basic Research Project of China(973Program)(2014CB339802,2014CB339806)Major National Development Project of Scientific Instrument and Equipment(2017YFF0106300,2016YFF0100503)Tianjin Research Program of Application Foundation and Advanced Technology(15JCZDJC31700)Key Scientific and Technological Project of Science and Technology Commission of Shanghai Municipality(STCSM)(15DZ0500102)Shanghai Leading Talent(2016-019)Young Yangtze River Scholar(Q2016212)Tianjin Special Program for Talent Development
文摘In this work, it has been demonstrated that in order to fully understand the terahertz(THz) pulse generation process during femtosecond laser filamentation, the interaction between THz wave and air plasma has to be taken into account. This interaction is mainly associated with the spatial confinement of the THz pulse by the plasma column, which could be described by the one-dimensional negative dielectric(1DND) waveguide model. By combining the 1 DND model with the conventional four-wave mixing(4WM) and photocurrent(PC) models,the variation of THz spectral amplitude and width obtained in experiments could be better understood. Finally, a three-step procedure, with 1DND bridging 4WM and PC processes, has been established for the first time to describe the underlying mechanism of THz radiation from plasma sources.
基金supported by the National Natural Science Foundation of China(21172271)Natural Science Foundation of Guangdong Province,China(Grant No.S2011020001231)the Fundamental Research Funds for the Central Universities(11lgpy75).
文摘Xyloketals,a new type of antioxidants from a marine mangrove fungus,have potential pharmacological properties.In this paper,the radical-scavenging activities of a series of synthetic xyloketals and related chromanes toward 2,2-diphenyl-1-picrylhydrazyl(DPPH)and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS)were evaluated by absorption spectrometry.One of the compounds(compound 10)displayed significant antioxidative action against DPPH and ABTS.A structure-activity analysis showed that the reactive sites on these compounds correlated with a hydroxygroup and also with ketal or aromatic H substituents.Based in part on a density functional theory(DFT)calculation of compound 10,the antioxidant mechanism of this chromane was deduced as a possible radical-scavenging mechanism by a sequential proton loss electron-transfer(SPLET)process.
基金We gratefully acknowledge funding supporting from the National Natural Science Foundation of China(No.11804040)the Scientific and Technological Research of Chongqing Municipal Education Commission(No.KJZD-K202100602)G.Z.is supported in part by RIE2020 Advanced Manufacturing and Engineering Programmatic(No.A1898b0043).
文摘Thermal conductivity of two-dimensional(2D)materials has gained prominence due to the attractive applications in thermal management and thermoelectric devices.In this work,we present a new member of bilayer 2D boron allotropes,denoted as bilayerβ12 borophene,and study the thermal transport properties by solving phonon Boltzmann transport equation based on density functional theory.Based on quantitative chemical bonding analysis,we identify large degrees of covalent bonding of the interlayer interaction.In comparison to its monolayer counterpart,the bilayer exhibits much higher in-plane thermal conductivity despite the lower phonon group velocity and buckling structure,inferring a new physical mechanism.The thermal conductivity(κ)of bilayerβ_(12)borophene at 300 K is 140.5(86.3)W·m^(-1)·K^(-1)along armchair(zigzag)direction,andκ_(armchair)is about 52.7%higher than that of monolayerβ12 borophene.The abnormal enhancement is attributed to the suppressed phonon scattering possibility and elongation of phonon lifetime.More interesting,after forming bilayerβ12 borophene through interlayer covalent bonding,the dominated phonon branch to thermal conductivity changes to transverse acoustic phonons from out-of-plane flexural acoustic(ZA)phonons in the monolayer borophene.Our study elucidates the rich thermal transport characteristics in bilayer covalently bonded 2D materials,and injects fresh insights into the phonon engineering of 2D borophene relevant for emergent thermal management applications.
