Rational design of photocatalyst to maximize the use of sunlight is one of the issues to be solved in photocatalysis technology.In this study,the CuFe_(2)O_(4)@C/Cd_(0.9)Zn_(0.1)S(CFO@C/CZS)S-scheme photocatalyst with...Rational design of photocatalyst to maximize the use of sunlight is one of the issues to be solved in photocatalysis technology.In this study,the CuFe_(2)O_(4)@C/Cd_(0.9)Zn_(0.1)S(CFO@C/CZS)S-scheme photocatalyst with photothermal effect was synthesized by ultrasonic self-assembly combined with calcination.The dark CFO@C absorbed visible light and partly converted into heat to promote the hydrogen evolution reaction.The presence of heterojunctions inhibited the photogenerated electron-hole recombination.The graphite-carbon layer provided a stable channel for electron transfer,and the presence of magnetic CFO made recycle easier.Under the action of photothermal assistance and heterojunction,the hydrogen evolution rate of the optimal CFO@C/CZS was 80.79 mmol g^(-1) h^(-1),which was 2.55 times and 260.61 times of that of pure CZS and CFO@C,respectively.Notably,the composite samples also exhibit excellent stability and a wide range of environmental adaptability.Through experimental tests and first-principles simulation calculation methods,the plausible mechanism of photoactivity enhancement was proposed.This work provided a feasible strategy of photothermal assistance for the development of heterojunction photocatalysts with distinctive hydrogen evolution.展开更多
Piezoelectric materials have advantages of fine-tuning photocatalytic performance through harvesting mechanical energy and open a new avenue in facilitating green catalytic reaction.Herein,polyvinylidene fluoride(PVDF...Piezoelectric materials have advantages of fine-tuning photocatalytic performance through harvesting mechanical energy and open a new avenue in facilitating green catalytic reaction.Herein,polyvinylidene fluoride(PVDF),a flexible piezoelectric material,was introduced to synthesize a novel Cd_(0.9)Zn_(0.1)S-ZnO@C/PVDF(CZS-ZO@C/PVDF)piezo-photocatalytic film by spin coating and immersion phase conversion method.Benefiting from the piezoelectricity of PVDF and the internal electric field(IEF)of CZS-ZO@C Step-scheme(S-Scheme)heterojunction,CZS-ZO@C/PVDF was able to induce a hydrogen generation rate of 34.9 mmol g^(−1)h^(−1)activated by ultrasound and visible light(U-L),which is∼17.5 times of Cd_(0.9)Zn_(0.1)S/PVDF(CZS/PVDF)and∼7.4 times of the photocatalysis rate activated by visible light only(L).Piezoelectric measurements and COMSOL simulation illustrated the excellent piezoelectricity of CZS-ZO@C/PVDF film,which exhibits a piezoelectric coefficient(d33)of 9.9 pm V−1 and a piezoelectric potential of 874 mV(under 0.5 MPa).The reaction mechanism for the exceptional piezo-photocatalytic performance was finally disclosed through density functional theory(DFT)calculation and electrochemical tests.This study enriches the application scope of piezoelectric materials in sustainable energy catalysis and provides a new direction to develop efficient piezoelectric photocatalysts.展开更多
Cu-based catalysts have been extensively used in methanol steam reforming(MSR)reactions because of their low cost and high effi ciency.ZnO is often used in commercial Cu-based catalysts as both a structural and an ele...Cu-based catalysts have been extensively used in methanol steam reforming(MSR)reactions because of their low cost and high effi ciency.ZnO is often used in commercial Cu-based catalysts as both a structural and an electronic promoter to stabilize metal Cu nanoparticles and modify metal–support interfaces.Still,the further addition of chemical promoters is essential to further enhance the MSR reaction performance of the Cu/ZnO catalyst.In this work,CeO_(2)-doped Cu/ZnO catalysts were prepared using the coprecipitation method,and the eff ects of CeO_(2)on Cu-based catalysts were systematically investigated.Doping with appropriate CeO_(2)amounts could stabilize small Cu nanoparticles through a strong interaction between CeO_(2)and Cu,leading to the formation of more Cu+–ZnO x interfacial sites.However,higher CeO_(2)contents resulted in the formation of larger Cu nanoparticles and an excess of Cu+–CeO x interfacial sites.Consequently,the Cu/5CeO_(2)/ZnO catalyst with maximal Cu–ZnO interfaces exhibited the highest H 2 production rate of 94.6 mmolH2/(gcat·h),which was 1.5 and 10.2 times higher than those of Cu/ZnO and Cu/CeO_(2),respectively.展开更多
Electrochemical CO_(2)reduction(CO_(2)RR)over molecular catalysts is a paramount approach for CO_(2)conversion to CO.Herein,we report a novel phthalocyanine-derived catalyst synthesized by a two-step method with a muc...Electrochemical CO_(2)reduction(CO_(2)RR)over molecular catalysts is a paramount approach for CO_(2)conversion to CO.Herein,we report a novel phthalocyanine-derived catalyst synthesized by a two-step method with a much improved electroconductivity.Furthermore,the catalyst contains both Ni-N4sites and highly dispersed metallic Ni nanoclusters,leading to an increased CO_(2)RR currents by two folds.Isotope labelling study and in situ spectroscopic analysis demonstrate that the existence of metallic Ni nanoclusters is the key factor for the activity enhancement and can shift the CO_(2)RR mechanism from being electron transfer(ET)-limited(forming*COO^(-))to concerted proton-electron transfer(CPET)-limited(forming CO).展开更多
Reductive pretreatment is an important step for activating supported metal catalysts but has received little attention.In this study,reconstruction of the supported nickel catalyst was found to be sensitive to pretrea...Reductive pretreatment is an important step for activating supported metal catalysts but has received little attention.In this study,reconstruction of the supported nickel catalyst was found to be sensitive to pretreatment conditions.In contrast to the traditional activation procedure in hydrogen,activating the catalyst in syngas created supported Ni nanoparticles with a polycrystalline structure containing an abundance of grain boundaries.The unique post-activation catalyst structure offered enhanced CO adsorption and an improved CO methanation rate.The current strategy to tune the catalyst structure via manipulating the activation conditions can potentially guide the rational design of other supported metal catalysts.展开更多
Great attention has been paid to cofacial porphyrins due to their many unique advantages over their monomeric analogs.However,their synthesis is usually complicated.In this work,a facile impregnation method for prepar...Great attention has been paid to cofacial porphyrins due to their many unique advantages over their monomeric analogs.However,their synthesis is usually complicated.In this work,a facile impregnation method for preparing heterogenized,cofacially stacked porphyrins is proposed.An anionic porphyrin is introduced as an underlayer for immobilization of cationic cobalt porphyrin via electrostatic force.The metal center of the underlying molecule contributes to the electronic structure of the upper cationic cobalt porphyrin.Screening reveals the anionic iron porphyrin to be the most efficient underlayer molecule,lowering the activation energy barrier of CO_(2) electroreduction,with an improved turnover frequency by 74%to8.0 s~(-1)at-0.6 V versus RHE.展开更多
Electromagnetic ion cyclotron(EMIC)waves are widely believed to play an important role in influencing the radiation belt and ring current dynamics.Most studies have investigated the effects or characteristics of EMIC ...Electromagnetic ion cyclotron(EMIC)waves are widely believed to play an important role in influencing the radiation belt and ring current dynamics.Most studies have investigated the effects or characteristics of EMIC waves by assuming their left-handed polarization.However,recent studies have found that the reversal of polarization,which occurs at higher latitudes along the wave propagation path,can change the wave-induced pitch angle diffusion coefficients.Whether such a polarization reversal can influence the global ring current dynamics remains unknown.In this study,we investigate the ring current dynamics and proton precipitation loss in association with polarization-reversed EMIC waves by using the ring current-atmosphere interactions model(RAM).The results indicate that the polarization reversal of H-band EMIC waves can truly decrease the scattering rates of protons of 10 to 50 keV or>100 keV in comparison with the scenario in which the EMIC waves are considered purely left-handed polarized.Additionally,the global ring current intensity and proton precipitation may be slightly affected by the polarization reversal,especially during prestorm time and the recovery phase,but the effects are not large during the main phase.This is probably because the H-band EMIC waves contribute to the proton scattering loss primarily at E<10 keV,an energy range that is not strongly affected by the polarization reversal.展开更多
Lysine-specific demethylase 4 A(KDM4A,also named JMJD2A,KIA0677,or JHDM3A)is a demethylase that can remove methyl groups from histones H3K9me2/3,H3K36me2/3,and H1.4K26me2/me3.Accumulating evidence suggests that KDM4A ...Lysine-specific demethylase 4 A(KDM4A,also named JMJD2A,KIA0677,or JHDM3A)is a demethylase that can remove methyl groups from histones H3K9me2/3,H3K36me2/3,and H1.4K26me2/me3.Accumulating evidence suggests that KDM4A is not only involved in body homeostasis(such as cell proliferation,migration and differentiation,and tissue development)but also associated with multiple human diseases,especially cancers.Recently,an increasing number of studies have shown that pharmacological inhibition of KDM4A significantly attenuates tumor progression in vitro and in vivo in a range of solid tumors and acute myeloid leukemia.Although there are several reviews on the roles of the KDM4 subfamily in cancer development and therapy,all of them only briefly introduce the roles of KDM4A in cancer without systematically summarizing the specific mechanisms of KDM4A in various physiological and pathological processes,especially in tumorigenesis,which greatly limits advances in the understanding of the roles of KDM4A in a variety of cancers,discovering targeted selective KDM4A inhibitors,and exploring the adaptive profiles of KDM4A antagonists.Herein,we present the structure and functions of KDM4A,simply outline the functions of KDM4A in homeostasis and non-cancer diseases,summarize the role of KDM4A and its distinct target genes in the development of a variety of cancers,systematically classify KDM4A inhibitors,summarize the difficulties encountered in the research of KDM4A and the discovery of related drugs,and provide the corresponding solutions,which would contribute to understanding the recent research trends on KDM4A and advancing the progression of KDM4A as a drug target in cancer therapy.展开更多
Synthetic chemistry plays an indispensable role in drug discovery,contributing to hit compounds identification,lead compounds optimization,candidate drugs preparation,and so on.As Nobel Prize laureate James Black emph...Synthetic chemistry plays an indispensable role in drug discovery,contributing to hit compounds identification,lead compounds optimization,candidate drugs preparation,and so on.As Nobel Prize laureate James Black emphasized,“the most fruitful basis for the discovery of a new drug is to start with an old drug”1.Late-stage modification or functionalization of drugs,natural products and bioactive compounds have garnered significant interest due to its ability to introduce diverse elements into bioactive compounds promptly.Such modifications alter the chemical space and physiochemical properties of these compounds,ultimately influencing their potency and druggability.To enrich a toolbox of chemical modification methods for drug discovery,this review focuses on the incorporation of halogen,oxygen,and nitrogen—the ubiquitous elements in pharmacophore components of the marketed drugs—through late-stage modification in recent two decades,and discusses the state and challenges faced in these fields.We also emphasize that increasing cooperation between chemists and pharmacists may be conducive to the rapid discovery of new activities of the functionalized molecules.Ultimately,we hope this review would serve as a valuable resource,facilitating the application of late-stage modification in the construction of novel molecules and inspiring innovative concepts for designing and building new drugs.展开更多
The CO_(2)catalytic hydrogenation represents a promising approach for gas-phase CO_(2)utilization in a direct manner.Due to its excellent hydrogenation ability,nickel has been widely studied and has shown good activit...The CO_(2)catalytic hydrogenation represents a promising approach for gas-phase CO_(2)utilization in a direct manner.Due to its excellent hydrogenation ability,nickel has been widely studied and has shown good activities in CO_(2)hydrogenation reactions,in addition to its high availability and low price.However,Ni-based catalysts are prone to sintering under elevated temperatures,leading to unstable catalytic performance.In the present study,various characterization techniques were employed to study the structural evolution of Ni/SiO_(2)during CO_(2)hydrogenation.An anti-sintering phenomenon is observed for both 9%Ni/SiO_(2)and 1%Ni/SiO_(2)during CO_(2)hydrogenation at 400℃.Results revealed that Ni species were re-dispersed into smaller-sized nanoparticles and formed Ni^(0)active species.While interestingly,this anti-sintering phenomenon leads to distinct outcomes for two catalysts,with a gradual increase in both reactivity and CH_(4)selectivity for 9%Ni/SiO_(2)presumably due to the formation of abundant surface Ni°from redispersion,while an apparent decreasing trend of CH_(4)selectivity for 1%Ni/SiO_(2)sample,presumably due to the formation of ultra-small nanoparticles that diffuse and partially filled the mesoporous pores of the silica support over time.Finally,the redispersion phenomenon was found relevant to the H_(2)gas in the reaction environment and enhanced as the H_(2)concentration increased.This finding is believed to provide in-depth insights into the structural evolution of Ni-based catalysts and product selectivity control in CO_(2)hydrogenation reactions.展开更多
In the wake of the research community gaining deep understanding about control-hijacking attacks,data-oriented attacks have emerged.Among data-oriented attacks,data structure manipulation attack(DSMA)is a major catego...In the wake of the research community gaining deep understanding about control-hijacking attacks,data-oriented attacks have emerged.Among data-oriented attacks,data structure manipulation attack(DSMA)is a major category.Pioneering research was conducted and shows that DSMA is able to circumvent the most effective defenses against control-hijacking attacks-DEP,ASLR and CFI.Up to this day,only two defense techniques have demonstrated their effectiveness:Data Flow Integrity(DFI)and Data Structure Layout Randomization(DSLR).However,DFI has high performance overhead,and dynamic DSLR has two main limitations.L-1:Randomizing a large set of data structures will significantly affect the performance.L-2:To be practical,only a fixed sub-set of data structures are randomized.In the case that the data structures targeted by an attack are not covered,dynamic DSLR is essentially noneffective.To address these two limitations,we propose a novel technique,feedback-control-based adaptive DSLR and build a system named SALADSPlus.SALADSPlus seeks to optimize the trade-off between security and cost through feedback control.Using a novel feedback-control-based adaptive algorithm extended from the Upper Confidence Bound(UCB)algorithm,the defender(controller)uses the feedbacks(cost-effectiveness)from previous randomization cycles to adaptively choose the set of data structures to randomize(the next action).Different from dynamic DSLR,the set of randomized data structures are adaptively changed based on the feedbacks.To obtain the feedbacks,SALADSPlus inserts canary in each data structure at the time of compilation.We have implemented SALADSPlus based on gcc-4.5.0.Experimental results show that the runtime overheads are 1.8%,3.7%,and 5.3% when the randomization cycles are selected as 10s,5s,and 1s respectively.展开更多
对高效催化剂进行多尺度调控可优化中间体的吸附能量(原子层面),并实现快速传质(三维宏观层面),这对于提升整体水分解性能至关重要.在本工作中,我们首先在镍铁氢氧化物中引入氧空位,然后通过磷化反应将其转化为具有纳米阵列形态的NiFe-V...对高效催化剂进行多尺度调控可优化中间体的吸附能量(原子层面),并实现快速传质(三维宏观层面),这对于提升整体水分解性能至关重要.在本工作中,我们首先在镍铁氢氧化物中引入氧空位,然后通过磷化反应将其转化为具有纳米阵列形态的NiFe-Vo-P催化剂.在析氧反应催化过程中,NiFe-Vo-P表面会原位形成磷酸盐阴离子及具有催化活性的Ni(Fe)OOH,能显著优化反应中间体的吸附强度.结果表明,NiFeVo-P在过电位为289 mV时电流密度可达1.5 A cm^(-2).同时,其超亲水/超疏气纳米阵列形貌可有效促进传质,在25和70℃的条件下,可在~2.0V的电池电压下分别获得580 mA cm^(-2)和1.0 A cm^(-2)的电流密度,是未进行超疏气形貌工程催化剂的电流密度的2倍以上.展开更多
Cu-based catalysts with excellent activity at low temperatures are widely used for methanol steam reforming(MSR)but suffer from deactivation problems.The present work aims to elucidate the deactivation and regeneratio...Cu-based catalysts with excellent activity at low temperatures are widely used for methanol steam reforming(MSR)but suffer from deactivation problems.The present work aims to elucidate the deactivation and regeneration mechanisms of the commercial Cu/ZnO/Al_(2)O_(3) catalyst in low temperature MSR.By employing a series of(quasi)in situ characterization methods,it is found that the deactivation of the catalyst at a high weight hourly space velocity(WHSV)and a low reaction temperature is mainly due to the poisoning of Cu species associated with surface-oxygenated species with less Cu sintering,rather than carbon deposition,and strong metal-support interaction(SMSI).An in situ regeneration method was developed for the deactivated commercial Cu/ZnO/Al_(2)O_(3) catalyst via the simultaneous supply of O_(2).It is shown that the addition of O_(2)(≥1 vol%)can reverse the deactivation caused by surface-oxygenated poisoning due to the weak interaction between formed surface copper oxide and surface-oxygenated species,facilitating their desorption,but not deactivation caused by sintering,thereby partially restoring the catalytic activity.展开更多
基金supported by the Shandong Provincial Natural Science Foundation(ZR2022ME179,ZR2021QE086)the Shandong Provincial Key Research and Development Program(Public Welfare Science and Technology Research)(2019GGX103010)+2 种基金the Science and Technology Planning Project of Higher School in Shandong Province(J18KA243)the Liaocheng Key Research and Development Program(Policy guidance category)(2022YDSF90)the Liaocheng University High-level Talents&PhD Research Startup Foundation(318051619)。
文摘Rational design of photocatalyst to maximize the use of sunlight is one of the issues to be solved in photocatalysis technology.In this study,the CuFe_(2)O_(4)@C/Cd_(0.9)Zn_(0.1)S(CFO@C/CZS)S-scheme photocatalyst with photothermal effect was synthesized by ultrasonic self-assembly combined with calcination.The dark CFO@C absorbed visible light and partly converted into heat to promote the hydrogen evolution reaction.The presence of heterojunctions inhibited the photogenerated electron-hole recombination.The graphite-carbon layer provided a stable channel for electron transfer,and the presence of magnetic CFO made recycle easier.Under the action of photothermal assistance and heterojunction,the hydrogen evolution rate of the optimal CFO@C/CZS was 80.79 mmol g^(-1) h^(-1),which was 2.55 times and 260.61 times of that of pure CZS and CFO@C,respectively.Notably,the composite samples also exhibit excellent stability and a wide range of environmental adaptability.Through experimental tests and first-principles simulation calculation methods,the plausible mechanism of photoactivity enhancement was proposed.This work provided a feasible strategy of photothermal assistance for the development of heterojunction photocatalysts with distinctive hydrogen evolution.
基金supported by the Shandong Provincial Natural Science Foundation,China(ZR2022ME179,ZR2021ME046).
文摘Piezoelectric materials have advantages of fine-tuning photocatalytic performance through harvesting mechanical energy and open a new avenue in facilitating green catalytic reaction.Herein,polyvinylidene fluoride(PVDF),a flexible piezoelectric material,was introduced to synthesize a novel Cd_(0.9)Zn_(0.1)S-ZnO@C/PVDF(CZS-ZO@C/PVDF)piezo-photocatalytic film by spin coating and immersion phase conversion method.Benefiting from the piezoelectricity of PVDF and the internal electric field(IEF)of CZS-ZO@C Step-scheme(S-Scheme)heterojunction,CZS-ZO@C/PVDF was able to induce a hydrogen generation rate of 34.9 mmol g^(−1)h^(−1)activated by ultrasound and visible light(U-L),which is∼17.5 times of Cd_(0.9)Zn_(0.1)S/PVDF(CZS/PVDF)and∼7.4 times of the photocatalysis rate activated by visible light only(L).Piezoelectric measurements and COMSOL simulation illustrated the excellent piezoelectricity of CZS-ZO@C/PVDF film,which exhibits a piezoelectric coefficient(d33)of 9.9 pm V−1 and a piezoelectric potential of 874 mV(under 0.5 MPa).The reaction mechanism for the exceptional piezo-photocatalytic performance was finally disclosed through density functional theory(DFT)calculation and electrochemical tests.This study enriches the application scope of piezoelectric materials in sustainable energy catalysis and provides a new direction to develop efficient piezoelectric photocatalysts.
基金This work was supported by the National Key R&D Program of China(2022YFB3805504),National Natural Science Foundation of China(22078089)China Postdoctoral Science Foundation(2023M731081)+3 种基金Shanghai Pilot Program for Basic Research(22TQ1400100-7)the Basic Research Program of Science and Technology Commission of Shanghai Municipality(22JC1400600)Open Foundation of Shanghai Jiao Tong University Shaoxing Research Institute of Renewable Energy and Molecular Engineering(Grant No.JDSX2022046)Shanghai Super Postdoctoral Fellow.
文摘Cu-based catalysts have been extensively used in methanol steam reforming(MSR)reactions because of their low cost and high effi ciency.ZnO is often used in commercial Cu-based catalysts as both a structural and an electronic promoter to stabilize metal Cu nanoparticles and modify metal–support interfaces.Still,the further addition of chemical promoters is essential to further enhance the MSR reaction performance of the Cu/ZnO catalyst.In this work,CeO_(2)-doped Cu/ZnO catalysts were prepared using the coprecipitation method,and the eff ects of CeO_(2)on Cu-based catalysts were systematically investigated.Doping with appropriate CeO_(2)amounts could stabilize small Cu nanoparticles through a strong interaction between CeO_(2)and Cu,leading to the formation of more Cu+–ZnO x interfacial sites.However,higher CeO_(2)contents resulted in the formation of larger Cu nanoparticles and an excess of Cu+–CeO x interfacial sites.Consequently,the Cu/5CeO_(2)/ZnO catalyst with maximal Cu–ZnO interfaces exhibited the highest H 2 production rate of 94.6 mmolH2/(gcat·h),which was 1.5 and 10.2 times higher than those of Cu/ZnO and Cu/CeO_(2),respectively.
基金sponsored by the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning and Shanghai Sailing Program(19YF1410600)。
文摘Electrochemical CO_(2)reduction(CO_(2)RR)over molecular catalysts is a paramount approach for CO_(2)conversion to CO.Herein,we report a novel phthalocyanine-derived catalyst synthesized by a two-step method with a much improved electroconductivity.Furthermore,the catalyst contains both Ni-N4sites and highly dispersed metallic Ni nanoclusters,leading to an increased CO_(2)RR currents by two folds.Isotope labelling study and in situ spectroscopic analysis demonstrate that the existence of metallic Ni nanoclusters is the key factor for the activity enhancement and can shift the CO_(2)RR mechanism from being electron transfer(ET)-limited(forming*COO^(-))to concerted proton-electron transfer(CPET)-limited(forming CO).
基金sponsored by the National Natural Science Foundation of China (22078089 and 22122807)Natural Science Foundation of Shanghai (21ZR1425700)+1 种基金Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning and Shanghai Sailing Program (19YF1410600)The research at Lehigh University was supported by the Center for Understanding and Control of Acid Gas-Induced Evolution of Materials for Energy (UNCAGE-ME), an Energy Frontier Research Center funded by Department of Energy, Office of Science, Office of Basic Energy Sciences (DE-SC0012577)
文摘Reductive pretreatment is an important step for activating supported metal catalysts but has received little attention.In this study,reconstruction of the supported nickel catalyst was found to be sensitive to pretreatment conditions.In contrast to the traditional activation procedure in hydrogen,activating the catalyst in syngas created supported Ni nanoparticles with a polycrystalline structure containing an abundance of grain boundaries.The unique post-activation catalyst structure offered enhanced CO adsorption and an improved CO methanation rate.The current strategy to tune the catalyst structure via manipulating the activation conditions can potentially guide the rational design of other supported metal catalysts.
基金sponsored by the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning and Shanghai Sailing Program(No.19YF1410600)the Young Scientists Fund of the National Natural Science Foundation of China(No.21905240)the State Key Laboratory of Marine Pollution(SKLMP)Seed Collaborative Research Fund。
文摘Great attention has been paid to cofacial porphyrins due to their many unique advantages over their monomeric analogs.However,their synthesis is usually complicated.In this work,a facile impregnation method for preparing heterogenized,cofacially stacked porphyrins is proposed.An anionic porphyrin is introduced as an underlayer for immobilization of cationic cobalt porphyrin via electrostatic force.The metal center of the underlying molecule contributes to the electronic structure of the upper cationic cobalt porphyrin.Screening reveals the anionic iron porphyrin to be the most efficient underlayer molecule,lowering the activation energy barrier of CO_(2) electroreduction,with an improved turnover frequency by 74%to8.0 s~(-1)at-0.6 V versus RHE.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.41974192 and 41821003)Work at Los Alamos was performed under the auspices of the U.S.Department of Energy(Contract No.89233218CNA000001)was partially funded by an NSF grant(Grant No.IAA2027951).
文摘Electromagnetic ion cyclotron(EMIC)waves are widely believed to play an important role in influencing the radiation belt and ring current dynamics.Most studies have investigated the effects or characteristics of EMIC waves by assuming their left-handed polarization.However,recent studies have found that the reversal of polarization,which occurs at higher latitudes along the wave propagation path,can change the wave-induced pitch angle diffusion coefficients.Whether such a polarization reversal can influence the global ring current dynamics remains unknown.In this study,we investigate the ring current dynamics and proton precipitation loss in association with polarization-reversed EMIC waves by using the ring current-atmosphere interactions model(RAM).The results indicate that the polarization reversal of H-band EMIC waves can truly decrease the scattering rates of protons of 10 to 50 keV or>100 keV in comparison with the scenario in which the EMIC waves are considered purely left-handed polarized.Additionally,the global ring current intensity and proton precipitation may be slightly affected by the polarization reversal,especially during prestorm time and the recovery phase,but the effects are not large during the main phase.This is probably because the H-band EMIC waves contribute to the proton scattering loss primarily at E<10 keV,an energy range that is not strongly affected by the polarization reversal.
基金supported by the National Natural Science Foundation of China(No.31972821)the General Scientific Research Project of Education of Zhejiang Province,China(No.422204123)the Starting Research Fund of Ningbo University,Zhejiang,China(No.421912073).
文摘Lysine-specific demethylase 4 A(KDM4A,also named JMJD2A,KIA0677,or JHDM3A)is a demethylase that can remove methyl groups from histones H3K9me2/3,H3K36me2/3,and H1.4K26me2/me3.Accumulating evidence suggests that KDM4A is not only involved in body homeostasis(such as cell proliferation,migration and differentiation,and tissue development)but also associated with multiple human diseases,especially cancers.Recently,an increasing number of studies have shown that pharmacological inhibition of KDM4A significantly attenuates tumor progression in vitro and in vivo in a range of solid tumors and acute myeloid leukemia.Although there are several reviews on the roles of the KDM4 subfamily in cancer development and therapy,all of them only briefly introduce the roles of KDM4A in cancer without systematically summarizing the specific mechanisms of KDM4A in various physiological and pathological processes,especially in tumorigenesis,which greatly limits advances in the understanding of the roles of KDM4A in a variety of cancers,discovering targeted selective KDM4A inhibitors,and exploring the adaptive profiles of KDM4A antagonists.Herein,we present the structure and functions of KDM4A,simply outline the functions of KDM4A in homeostasis and non-cancer diseases,summarize the role of KDM4A and its distinct target genes in the development of a variety of cancers,systematically classify KDM4A inhibitors,summarize the difficulties encountered in the research of KDM4A and the discovery of related drugs,and provide the corresponding solutions,which would contribute to understanding the recent research trends on KDM4A and advancing the progression of KDM4A as a drug target in cancer therapy.
基金Financial support from the National Key R&D Program of China(No.2021YFA1501700)the National Natural Science Foundation of China(Nos.22293014,22131002,22161142019,81821004)+1 种基金the Ministry of Science and Technology of China Changping Laboratory,Peking University Special Fund for COVID-19the New Cornerstone Science Foundation through the XPLORER PRIZE。
文摘Synthetic chemistry plays an indispensable role in drug discovery,contributing to hit compounds identification,lead compounds optimization,candidate drugs preparation,and so on.As Nobel Prize laureate James Black emphasized,“the most fruitful basis for the discovery of a new drug is to start with an old drug”1.Late-stage modification or functionalization of drugs,natural products and bioactive compounds have garnered significant interest due to its ability to introduce diverse elements into bioactive compounds promptly.Such modifications alter the chemical space and physiochemical properties of these compounds,ultimately influencing their potency and druggability.To enrich a toolbox of chemical modification methods for drug discovery,this review focuses on the incorporation of halogen,oxygen,and nitrogen—the ubiquitous elements in pharmacophore components of the marketed drugs—through late-stage modification in recent two decades,and discusses the state and challenges faced in these fields.We also emphasize that increasing cooperation between chemists and pharmacists may be conducive to the rapid discovery of new activities of the functionalized molecules.Ultimately,we hope this review would serve as a valuable resource,facilitating the application of late-stage modification in the construction of novel molecules and inspiring innovative concepts for designing and building new drugs.
基金supported by the Shanghai Post-Doctoral Excellence Program(No.2021232)Y.He thanks the National Natural Science Foundation of China(No.22202131)+3 种基金the Shanghai Science and Technology Development Funds of“Rising Star”Sailing Program(No.22YF1419400)for the financial supportM.Zhu thanks the research funding sponsored by the National Natural Science Foundation of China(No.22078089)the Shanghai Special Program for Fundamental Research(No.22TQ1400100-7)the Basic Research Program of Science and Technology Commission of Shanghai Municipality(No.22JC1400600)。
文摘The CO_(2)catalytic hydrogenation represents a promising approach for gas-phase CO_(2)utilization in a direct manner.Due to its excellent hydrogenation ability,nickel has been widely studied and has shown good activities in CO_(2)hydrogenation reactions,in addition to its high availability and low price.However,Ni-based catalysts are prone to sintering under elevated temperatures,leading to unstable catalytic performance.In the present study,various characterization techniques were employed to study the structural evolution of Ni/SiO_(2)during CO_(2)hydrogenation.An anti-sintering phenomenon is observed for both 9%Ni/SiO_(2)and 1%Ni/SiO_(2)during CO_(2)hydrogenation at 400℃.Results revealed that Ni species were re-dispersed into smaller-sized nanoparticles and formed Ni^(0)active species.While interestingly,this anti-sintering phenomenon leads to distinct outcomes for two catalysts,with a gradual increase in both reactivity and CH_(4)selectivity for 9%Ni/SiO_(2)presumably due to the formation of abundant surface Ni°from redispersion,while an apparent decreasing trend of CH_(4)selectivity for 1%Ni/SiO_(2)sample,presumably due to the formation of ultra-small nanoparticles that diffuse and partially filled the mesoporous pores of the silica support over time.Finally,the redispersion phenomenon was found relevant to the H_(2)gas in the reaction environment and enhanced as the H_(2)concentration increased.This finding is believed to provide in-depth insights into the structural evolution of Ni-based catalysts and product selectivity control in CO_(2)hydrogenation reactions.
基金supported by ARO W911NF-13-1-0421(MURI)NSF CNS-1422594NSF CNS-1505664.
文摘In the wake of the research community gaining deep understanding about control-hijacking attacks,data-oriented attacks have emerged.Among data-oriented attacks,data structure manipulation attack(DSMA)is a major category.Pioneering research was conducted and shows that DSMA is able to circumvent the most effective defenses against control-hijacking attacks-DEP,ASLR and CFI.Up to this day,only two defense techniques have demonstrated their effectiveness:Data Flow Integrity(DFI)and Data Structure Layout Randomization(DSLR).However,DFI has high performance overhead,and dynamic DSLR has two main limitations.L-1:Randomizing a large set of data structures will significantly affect the performance.L-2:To be practical,only a fixed sub-set of data structures are randomized.In the case that the data structures targeted by an attack are not covered,dynamic DSLR is essentially noneffective.To address these two limitations,we propose a novel technique,feedback-control-based adaptive DSLR and build a system named SALADSPlus.SALADSPlus seeks to optimize the trade-off between security and cost through feedback control.Using a novel feedback-control-based adaptive algorithm extended from the Upper Confidence Bound(UCB)algorithm,the defender(controller)uses the feedbacks(cost-effectiveness)from previous randomization cycles to adaptively choose the set of data structures to randomize(the next action).Different from dynamic DSLR,the set of randomized data structures are adaptively changed based on the feedbacks.To obtain the feedbacks,SALADSPlus inserts canary in each data structure at the time of compilation.We have implemented SALADSPlus based on gcc-4.5.0.Experimental results show that the runtime overheads are 1.8%,3.7%,and 5.3% when the randomization cycles are selected as 10s,5s,and 1s respectively.
基金supported by the National Key R&D Program of China(2021YFB3801301)the National Natural Science Foundation of China(22075076 and 22005098)the Central Government Funds for Guiding Local Science and Technology Development(2021Szvup040)。
文摘对高效催化剂进行多尺度调控可优化中间体的吸附能量(原子层面),并实现快速传质(三维宏观层面),这对于提升整体水分解性能至关重要.在本工作中,我们首先在镍铁氢氧化物中引入氧空位,然后通过磷化反应将其转化为具有纳米阵列形态的NiFe-Vo-P催化剂.在析氧反应催化过程中,NiFe-Vo-P表面会原位形成磷酸盐阴离子及具有催化活性的Ni(Fe)OOH,能显著优化反应中间体的吸附强度.结果表明,NiFeVo-P在过电位为289 mV时电流密度可达1.5 A cm^(-2).同时,其超亲水/超疏气纳米阵列形貌可有效促进传质,在25和70℃的条件下,可在~2.0V的电池电压下分别获得580 mA cm^(-2)和1.0 A cm^(-2)的电流密度,是未进行超疏气形貌工程催化剂的电流密度的2倍以上.
基金sponsored by the National Natural Science Foundation of China (22078089)the Program for Professor of Special Appointment (Eastern Scholar)at Shanghai Institutions of Higher LearningShanghai Sailing Program (19YF1410600)。
文摘Cu-based catalysts with excellent activity at low temperatures are widely used for methanol steam reforming(MSR)but suffer from deactivation problems.The present work aims to elucidate the deactivation and regeneration mechanisms of the commercial Cu/ZnO/Al_(2)O_(3) catalyst in low temperature MSR.By employing a series of(quasi)in situ characterization methods,it is found that the deactivation of the catalyst at a high weight hourly space velocity(WHSV)and a low reaction temperature is mainly due to the poisoning of Cu species associated with surface-oxygenated species with less Cu sintering,rather than carbon deposition,and strong metal-support interaction(SMSI).An in situ regeneration method was developed for the deactivated commercial Cu/ZnO/Al_(2)O_(3) catalyst via the simultaneous supply of O_(2).It is shown that the addition of O_(2)(≥1 vol%)can reverse the deactivation caused by surface-oxygenated poisoning due to the weak interaction between formed surface copper oxide and surface-oxygenated species,facilitating their desorption,but not deactivation caused by sintering,thereby partially restoring the catalytic activity.
