Highly thermally conductive graphitic film(GF)materials have become a competitive solution for the thermal management of high-power electronic devices.However,their catastrophic structural failure under extreme altern...Highly thermally conductive graphitic film(GF)materials have become a competitive solution for the thermal management of high-power electronic devices.However,their catastrophic structural failure under extreme alternating thermal/cold shock poses a significant challenge to reliability and safety.Here,we present the first investigation into the structural failure mechanism of GF during cyclic liquid nitrogen shocks(LNS),which reveals a bubbling process characterized by“permeation-diffusion-deformation”phenomenon.To overcome this long-standing structural weakness,a novel metal-nanoarmor strategy is proposed to construct a Cu-modified graphitic film(GF@Cu)with seamless heterointerface.This well-designed interface ensures superior structural stability for GF@Cu after hundreds of LNS cycles from 77 to 300 K.Moreover,GF@Cu maintains high thermal conductivity up to 1088 W m^(−1)K^(−1)with degradation of less than 5%even after 150 LNS cycles,superior to that of pure GF(50%degradation).Our work not only offers an opportunity to improve the robustness of graphitic films by the rational structural design but also facilitates the applications of thermally conductive carbon-based materials for future extreme thermal management in complex aerospace electronics.展开更多
Tree mortality significantly influences forest structure and function,yet our understanding of its dynamic patterns among a range of tree sizes and among different plant functional types(PFTs)remains incomplete.This s...Tree mortality significantly influences forest structure and function,yet our understanding of its dynamic patterns among a range of tree sizes and among different plant functional types(PFTs)remains incomplete.This study analysed size-dependent tree mortality in a temperate forest,encompassing 46 tree species and 32,565 individuals across different PFTs(i.e.,evergreen conifer vs.deciduous broadleaf species,shade-tolerant vs.shade-intolerant species).By employing all-subset regression procedures and logistic generalized linear mixed-effects models,we identified distinct mortality patterns influenced by biotic and abiotic factors.Our results showed a stable mortality patte rn in eve rgreen conifer species,contrasted by a declining pattern in deciduous broadleaf and shadetolerant,as well as shade-intolerant species,across size classes.The contribution to tree mortality of evergreen conifer species shifted from abiotic to biotic factors with increasing size,while the mortality of deciduous broadleaf species was mainly influenced by biotic factors,such as initial diameter at breast height(DBH)and conspecific negative density.For shade-tolerant species,the mortality of small individuals was mainly determined by initial DBH and conspecific negative density dependence,whereas the mortality of large individuals was subjected to the combined effect of biotic(competition from neighbours)and abiotic factors(i.e.,convexity and pH).As for shade-intolerant species,competition from neighbours was found to be the main driver of tree mortality throughout their growth stages.Thus,these insights enhance our understanding of forest dynamics by revealing the size-dependent and PFT-specific tree mortality patterns,which may inform strategies for maintaining forest diversity and resilience in temperate forest ecosystems.展开更多
Metallic zinc(Zn)is one of the most attractive multivalent-metal anode materials in post-lithium batteries because of its high abundance,low cost and high theoretical capacity.However,it usually suffers from large vol...Metallic zinc(Zn)is one of the most attractive multivalent-metal anode materials in post-lithium batteries because of its high abundance,low cost and high theoretical capacity.However,it usually suffers from large voltage polarization,low Coulombic efficiency and high propensity for dendritic failure during Zn stripping/plating,hindering the practical application in aqueous rechargeable zinc-metal batteries(AR-ZMBs).Here we demonstrate that anionic surfactant-assisted in situ surface alloying of Cu and Zn remarkably improves Zn reversibility of 3D nanoporous Zn electrodes for potential use as high-performance AR-ZMB anode materials.As a result of the zincophilic ZnxCuy alloy shell guiding uniform Zn deposition with a zero nucleation overpotential and facilitating Zn stripping via the ZnxCuy/Zn galvanic couples,the self-supported nanoporous ZnxCuy/Zn electrodes exhibit superior dendrite-free Zn stripping/plating behaviors in ambient aqueous electrolyte,with ultralow polarizations under current densities up to 50 mA cm^(‒2),exceptional stability for 1900 h and high Zn utilization.This enables AR-ZMB full cells constructed with nanoporous ZnxCuy/Zn anode and K_(z)MnO_(2)cathode to achieve specific energy of as high as~430 Wh kg^(‒1)with~99.8%Coulombic efficiency,and retain~86%after long-term cycles for>700 h.展开更多
Seedling stage has long been recognized as the bottleneck of forest regeneration,and the biotic and abiotic processes that dominate at seedling stage largely affect the dynamics of forest.Seedlings might be particular...Seedling stage has long been recognized as the bottleneck of forest regeneration,and the biotic and abiotic processes that dominate at seedling stage largely affect the dynamics of forest.Seedlings might be particularly vulnerable to climate stress,so elucidating the role of interannual climate variation in fostering community dynamics is crucial to understanding the response of forest to climate change.Using seedling survival data of 69 woody species collected for five consecutive years from a 25-ha permanent plot in a temperate deciduous forest,we identified the effects of biotic interactions and habitat factors on seedling survival,and examined how those effects changed over time.We found that interannual climate variations,followed by biotic interactions and habitat conditions,were the most significant predictors of seedling survival.Understory light showed a positive impact on seedling mortality,and seedling survival responded differently to soil and air temperature.Effects of conspecific neighbor density were significantly strengthened with the increase of maximum air temperature and vapor pressure deficits in the growing season,but were weakened by increased maximum soil temperature and precipitation in the non-growing season.Surprisingly,seedling survival was strongly correlated with interannual climate variability at all life stages,and the strength of the correlation increased with seedling age.In addition,the importance of biotic and abiotic factors on seedling survival differed significantly among species-trait groups.Thus,the neighborhood-mediated effects on mortality might be significantly contributing or even inverting the direct effects of varying abiotic conditions on seedling survival,and density-dependent effects could not be the only important factor influencing seedling survival at an early stage.展开更多
Currently,the top-rank-k has been widely applied to mine frequent patterns with a rank not exceeding k.In the existing algorithms,although a level-wise-search could fully mine the target patterns,it usually leads to t...Currently,the top-rank-k has been widely applied to mine frequent patterns with a rank not exceeding k.In the existing algorithms,although a level-wise-search could fully mine the target patterns,it usually leads to the delay of high rank patterns generation,resulting in the slow growth of the support threshold and the mining efficiency.Aiming at this problem,a greedy-strategy-based top-rank-k frequent patterns hybrid mining algorithm(GTK)is proposed in this paper.In this algorithm,top-rank-k patterns are stored in a static doubly linked list called RSL,and the patterns are divided into short patterns and long patterns.The short patterns generated by a rank-first-search always joins the two patterns of the highest rank in RSL that have not yet been joined.On the basis of the short patterns satisfying specific conditions,the long patterns are extracted through level-wise-search.To reduce redundancy,GTK improves the generation method of subsume index and designs the new pruning strategies of candidates.This algorithm also takes the use of reasonable pruning strategies to reduce the amount of computation to improve the computational speed.Real datasets and synthetic datasets are adopted in experiments to evaluate the proposed algorithm.The experimental results show the obvious advantages in both time efficiency and space efficiency of GTK.展开更多
Biodiversity conservation has long been a subject of extreme interest to community ecologists,with a particular focus on exploring the underlying causes of species diversity based on niche and neutral theories.This st...Biodiversity conservation has long been a subject of extreme interest to community ecologists,with a particular focus on exploring the underlying causes of species diversity based on niche and neutral theories.This study aims to identify the potential determinants of species diversity in a deciduous broad-leaved forest in the transitional region from subtropical to temperate climate in China.We collected woody plant data and environmental variables in a fully mapped 25-ha permanent forest plot,partitioned the beta-diversity into local contributions(LCBD)and species contributions(SCBD),and then applied multivariate linear regression analysis to test the effects of biotic and abiotic factors on alpha-diversity,LCBD,and SCBD.We used variation partitioning in combination with environmental variables and spatial distance to determine the contribution of environment-related variations versus spatial variations.Our results showed that the indices of alpha-diversity(i.e.,species abundance and richness)were positively correlated with soil available phosphorus(P)and negatively with slope.For the betadiversity,environment and space together explained nearly half of the variations in community composition.Approximately 60%of the variation of LCBD in the understory layer,40%in the substory layer,and 29%in the canopy layer were jointly explained by topographic,soil and biological variables,with biotic factors playing a dominant role in determining the beta-diversity.Species abundance accounted for a large proportion of the variations in SCBD in each vertical stratum,and niche position(NP)was the ecological trait that significantly affected the variations in SCBD in the substory and canopy layers.Our findings help to gain better understanding on how species diversity in forest ecosystem responds to environmental conditions and how it is influenced by biotic factors and ecological traits of species.展开更多
Mannich-type reactions are a widely used method for the synthesis of amines due to the readily availability of nucleophiles and electrophiles.However,the inclusion of alkylarenes instead of active carbon pronucleophil...Mannich-type reactions are a widely used method for the synthesis of amines due to the readily availability of nucleophiles and electrophiles.However,the inclusion of alkylarenes instead of active carbon pronucleophiles such as aldehydes and ketones in these addition reactions has been a challenge due to the inherent difficulty of benzylic deprotonation.In this study,we present a novel approach for the construction of N-sulfonyl amines via rhodium-catalyzed addition of unbiased benzylic C–H bonds to cyclic N-sulfonyl ketamines throughπ-coordination.This strategy enables the synthesis of a diverse range of N-sulfonyl amines,and subsequent diversification of the addition products showcases the synthetic potential of this protocol.展开更多
Solar-driven CO_(2)-to-fuel conversion assisted by another major greenhouse gas CH_(4)is promising to concurrently tackle energy shortage and global warming problems.However,current techniques still suffer from drawba...Solar-driven CO_(2)-to-fuel conversion assisted by another major greenhouse gas CH_(4)is promising to concurrently tackle energy shortage and global warming problems.However,current techniques still suffer from drawbacks of low efficiency,poor stability,and low selectivity.Here,a novel nanocomposite composed of interconnected Ni/MgAlOx nanoflakes grown on SiO_(2)particles with excellent spatial confinement of active sites is proposed for direct solar-driven CO_(2)-to-fuel conversion.An ultrahigh light-to-fuel efficiency up to 35.7%,high production rates of H_(2)(136.6 mmol min^(-1)g^(-1))and CO(148.2 mmol min^(-1)g^(-1)),excellent selectivity(H_(2)/CO ratio of 0.92),and good stability are reported simultaneously.These outstanding performances are attributed to strong metal-support interactions,improved CO_(2)absorption and activation,and decreased apparent activation energy under direct light illumination.MgAlO_(x)@SiO_(2)support helps to lower the activation energy of CH^(*) oxidation to CHO^(*) and improve the dissociation of CH_(4)to CH_(3)^(*) as confirmed by DFT calculations.Moreover,the lattice oxygen of MgAlO_(x) participates in the reaction and contributes to the removal of carbon deposition.This work provides promising routes for the conversion of greenhouse gasses into industrially valuable syngas with high efficiency,high selectivity,and benign sustainability.展开更多
The response of N_(2)O emissions to nitrogen(N)addition is usually positive,but its response to phosphorus(P)addition varies,and the underlying mechanisms for the changes in N_(2)O emissions remain unclear.We conducte...The response of N_(2)O emissions to nitrogen(N)addition is usually positive,but its response to phosphorus(P)addition varies,and the underlying mechanisms for the changes in N_(2)O emissions remain unclear.We conducted field studies to examine the response of N_(2)O emissions to N and P addition over two years in three typical alpine grasslands,alpine meadow(AM),alpine steppe(AS),and alpine cultivated grassland(CG)on the Qinghai-Tibet Plateau(QTP).Our results showed consistent increases in N_(2)O emissions under N addition alone or with P addition,and insignificant change in N_(2)O emissions under P addition alone in all three grasslands.N addition increased N_(2)O emissions directly in AM,by lowering soil pH in AS,and by lowering abundance of denitrification genes in CG.N and P co-addition increased N_(2)O emissions in AM and AS but only showed an interactive effect in AM.P addition enhanced the increase in N_(2)O emissions caused by N addition mainly by promoting plant growth in AM.Overall,our results illustrate that short-term P addition cannot alleviate the stimulation of N_(2)O emissions by N deposition in alpine grassland ecosystems,and may even further stimulate N_(2)O emissions.展开更多
This study analyzed the effects of male age and abstinence time on semen quality and explored the best abstinence time for Chinese males among different age groups.Semen parameters,including sperm kinetics,morphology,...This study analyzed the effects of male age and abstinence time on semen quality and explored the best abstinence time for Chinese males among different age groups.Semen parameters,including sperm kinetics,morphology,and DNA fragmentation index(DFI),were reviewed from 2952 men.Samples were divided into six age groups(≤25 years,26–30 years,31–35 years,36–40 years,41–45 years,and>45 years)and were divided into six groups according to different abstinence time(2 days,3 days,4 days,5 days,6 days,and 7 days).The differences in semen quality between the groups were compared,and the effect of age and abstinence time on semen quality was analyzed.Significant differences were observed in semen volume,progressive motility(PR),and DFI among the age groups(all P<0.05),and no significant differences were observed in sperm morphological parameters(all P>0.05).There were significant differences in semen volume,PR,and DFI among different abstinence time groups(all P<0.05)and no significant differences in sperm morphological parameters(all P>0.05).Pearson analysis showed that male age and abstinence time were both significantly correlated with sperm kinetics and DFI(both P<0.05),while no significant correlation was found with sperm morphological parameters(all P>0.05).The box plots and histograms of men’s age,abstinence time,and semen quality show that most semen quality parameters differ significantly between the 2 days and 7 days abstinence groups and other groups at different ages.Except for the sperm morphology parameters,sperm kinetic parameters and sperm DFI are linearly related to male age and abstinence time.展开更多
Aqueous multivalent-metal-ion intercalation chemistries hold genuine promise to develop safe and powerful microbatteries for potential use in many miniaturized electronics.However,their development is beset by state-o...Aqueous multivalent-metal-ion intercalation chemistries hold genuine promise to develop safe and powerful microbatteries for potential use in many miniaturized electronics.However,their development is beset by state-of-the-art electrode materials having practical capacities far below their theoretical values.Here we demonstrate that high compatibility between layered transition-metal oxide hosts and hydrated cation vips substantially boost their multi-electron-redox reactions to offer higher capacities and rate capability,based on typical bipolar vanadium oxides preintercalated with hydrated cations(M_(x)V_(2)O_(5)).When seamlessly integrated on Au current microcollectors with a three-dimensional bicontinuous nanoporous architecture that offers high pathways of electron transfer and ion transport,the constituent Zn_(x)V_(2)O_(5) exhibits specific capacity of as high as∼527 mAh g^(−1) at 5 mV s^(−1) and retains∼300 mAh g^(−1) at 200 mV s^(−1) in 1 M ZnSO_(4) aqueous electrolyte,outperforming the M_(x)V_(2)O_(5)(M=Li,Na,K,Mg).This allows aqueous rechargeable zinc-ion microbatteries constructed with symmetric nanoporous Zn_(x)V_(2)O_(5)/Au interdigital microelectrodes as anode and cathode to show high-density energy of∼358 mWh cm^(−3)(a value that is forty-fold higher than that of 4 V/500μAh Li thin film battery)at high levels of power delivery.展开更多
Designing highly active and robust platinum-free electrocatalysts for hydrogen evolution reaction is vital for large-scale and efficient production of hydrogen through electrochemical water splitting.Here,we report no...Designing highly active and robust platinum-free electrocatalysts for hydrogen evolution reaction is vital for large-scale and efficient production of hydrogen through electrochemical water splitting.Here,we report nonprecious intermetallic Cu_(5)Zr clusters that are in situ anchored on hierarchical nanoporous copper(NP Cu/Cu_(5)Zr)for efficient hydrogen evolution in alkaline medium.By virtue of hydroxygenated zirconium atoms activating their nearby Cu-Cu bridge sites with appropriate hydrogenbinding energy,the Cu_(5)Zr clusters have a high electrocatalytic activity toward the hydrogen evolution reaction.Associated with unique architecture featured with steady and bicontinuous nanoporous copper skeleton that facilitates electron transfer and electrolyte accessibility,the self-supported monolithic NP Cu/Cu_(5)Zr electrodes boost violent hydrogen gas release,realizing ultrahigh current density of 500mAcm^(-2) at a low potential of-280mV versus reversible hydrogen electrode,with exceptional stability in 1M KOH solution.The electrochemical properties outperform those of state-of-the-art nonprecious metal electrocatalysts and make them promising candidates as electrodes in water splitting devices.展开更多
Background and Aims:Oxaliplatin is widely used in can-cer chemotherapy with adverse effects such as liver toxicity.Magnesium isoglycyrrhizinate(MgIG)has hepatoprotective effects,but the underlying mechanism remains el...Background and Aims:Oxaliplatin is widely used in can-cer chemotherapy with adverse effects such as liver toxicity.Magnesium isoglycyrrhizinate(MgIG)has hepatoprotective effects,but the underlying mechanism remains elusive.The study’s aim was to investigate the mechanism underlying the hepatoprotective effects of MgIG against oxaliplatin-induced liver injury.Methods:A xenografted colorectal cancer mouse model was established with MC38 cells.Mice were given ox-aliplatin(6 mg/kg/week)for 5 weeks to mimic oxaliplatin-induced liver injury in vivo.LX-2 human hepatic stellate cell s(HSCs)were employed for in vitro studies.Serological tests,hematoxylin and eosin staining,oil red O staining and trans-mission electron microscopy were used for histopathological examinations.Real-time PCR,western blotting,immuno-fluorescence and immunohistochemical staining were used to determine Cx43 mRNA or protein levels.Flow cytometry was used to assay reactive oxygen species(ROS)and mito-chondrial membrane.Short hairpin RNA targeting Cx43 was lentivirally transduced in LX-2 cells.Ultra-high performance liquid chromatography-tandem mass spectrometry was used to determine MgIG and metabolite concentration.Results:MgIG(40 mg/kg/day)treatment significantly reduced se-rum aspartate transaminase(AST)and alanine transami-nase(ALT)levels in the mouse model,and alleviated liver pathological changes,including necrosis,sinusoidal expan-sion,mitochondrial damage,and fibrosis.MgIG reduced the abnormal expression of Cx43 in the mitochondria and nuclei of HSCs.MgIG inhibited the activation of HSCs via reducing ROS generation,mitochondrial dysfunction,and N-cadherin transcription.MgIG’s inhibition of HSCs activation was abol-ished after knockdown of Cx43 in LX-2 cells.Conclusions:Cx43 mediated MgIG’s hepatoprotective effects against ox-aliplatin-induced toxicity.展开更多
This article demonstrates a catalytic method for C(aryl)-C(alkyl) bond functionalization of N-sulfonyl amines. A cobalt(III)catalyst was used to cleave the C-C bond via β-carbon elimination, providing a metallacycle ...This article demonstrates a catalytic method for C(aryl)-C(alkyl) bond functionalization of N-sulfonyl amines. A cobalt(III)catalyst was used to cleave the C-C bond via β-carbon elimination, providing a metallacycle intermediate. Subsequent allylation,amidation, or alkenylation of the intermediate led to divergent conversions in the presence of diverse coupling partners. when the coupling partner was a diene, an insertion-type functionalization was realized with an exclusive 1,3-regioselectivity, in which both of the fragments derived from N-sulfonyl amines were utilized.展开更多
A simple one pot synthesis of polysubstituted pyrroles via ketenimine formation/Ag(l)-catalyzed alkyne cycloisomerisation has been developed.The easily accessible phosphorane ylide derivatives reacted with isocyanates...A simple one pot synthesis of polysubstituted pyrroles via ketenimine formation/Ag(l)-catalyzed alkyne cycloisomerisation has been developed.The easily accessible phosphorane ylide derivatives reacted with isocyanates,producing highly active ketenimines that were then treated with amines,which afforded substituted pyrroles by a S-exo-dig cyclization/isomerization in the presence of a Ag(l)catalyst in good overall yields.展开更多
基金the National Natural Science Foundation of China(Nos.52272046,52090030,52090031,52122301,51973191)the Natural Science Foundation of Zhejiang Province(LR23E020003)+4 种基金Shanxi-Zheda Institute of New Materials and Chemical Engineering(2021SZ-FR004,2022SZ-TD011,2022SZ-TD012,2022SZ-TD014)Hundred Talents Program of Zhejiang University(188020*194231701/113,112300+1944223R3/003,112300+1944223R3/004)the Fundamental Research Funds for the Central Universities(Nos.226-2023-00023,226-2023-00082,2021FZZX001-17,K20200060)National Key R&D Program of China(NO.2022YFA1205300,NO.2022YFA1205301,NO.2020YFF0204400,NO.2022YFF0609801)“Pioneer”and“Leading Goose”R&D Program of Zhejiang 2023C01190.
文摘Highly thermally conductive graphitic film(GF)materials have become a competitive solution for the thermal management of high-power electronic devices.However,their catastrophic structural failure under extreme alternating thermal/cold shock poses a significant challenge to reliability and safety.Here,we present the first investigation into the structural failure mechanism of GF during cyclic liquid nitrogen shocks(LNS),which reveals a bubbling process characterized by“permeation-diffusion-deformation”phenomenon.To overcome this long-standing structural weakness,a novel metal-nanoarmor strategy is proposed to construct a Cu-modified graphitic film(GF@Cu)with seamless heterointerface.This well-designed interface ensures superior structural stability for GF@Cu after hundreds of LNS cycles from 77 to 300 K.Moreover,GF@Cu maintains high thermal conductivity up to 1088 W m^(−1)K^(−1)with degradation of less than 5%even after 150 LNS cycles,superior to that of pure GF(50%degradation).Our work not only offers an opportunity to improve the robustness of graphitic films by the rational structural design but also facilitates the applications of thermally conductive carbon-based materials for future extreme thermal management in complex aerospace electronics.
基金supported by the China Postdoctoral Science Foundation (No.2023M733712)the National Natural Science Foundation of China (No.31971491)。
文摘Tree mortality significantly influences forest structure and function,yet our understanding of its dynamic patterns among a range of tree sizes and among different plant functional types(PFTs)remains incomplete.This study analysed size-dependent tree mortality in a temperate forest,encompassing 46 tree species and 32,565 individuals across different PFTs(i.e.,evergreen conifer vs.deciduous broadleaf species,shade-tolerant vs.shade-intolerant species).By employing all-subset regression procedures and logistic generalized linear mixed-effects models,we identified distinct mortality patterns influenced by biotic and abiotic factors.Our results showed a stable mortality patte rn in eve rgreen conifer species,contrasted by a declining pattern in deciduous broadleaf and shadetolerant,as well as shade-intolerant species,across size classes.The contribution to tree mortality of evergreen conifer species shifted from abiotic to biotic factors with increasing size,while the mortality of deciduous broadleaf species was mainly influenced by biotic factors,such as initial diameter at breast height(DBH)and conspecific negative density.For shade-tolerant species,the mortality of small individuals was mainly determined by initial DBH and conspecific negative density dependence,whereas the mortality of large individuals was subjected to the combined effect of biotic(competition from neighbours)and abiotic factors(i.e.,convexity and pH).As for shade-intolerant species,competition from neighbours was found to be the main driver of tree mortality throughout their growth stages.Thus,these insights enhance our understanding of forest dynamics by revealing the size-dependent and PFT-specific tree mortality patterns,which may inform strategies for maintaining forest diversity and resilience in temperate forest ecosystems.
基金supported by National Natural Science Foundation of China (No. 51871107, 52130101)Chang Jiang Scholar Program of China (Q2016064)+3 种基金the Program for JLU Science and Technology Innovative Research Team (JLUSTIRT, 2017TD-09)the Natural Science Foundation of Jilin Province (20200201019JC)the Fundamental Research Funds for the Central Universitiesthe Program for Innovative Research Team (in Science and Technology) in University of Jilin Province
文摘Metallic zinc(Zn)is one of the most attractive multivalent-metal anode materials in post-lithium batteries because of its high abundance,low cost and high theoretical capacity.However,it usually suffers from large voltage polarization,low Coulombic efficiency and high propensity for dendritic failure during Zn stripping/plating,hindering the practical application in aqueous rechargeable zinc-metal batteries(AR-ZMBs).Here we demonstrate that anionic surfactant-assisted in situ surface alloying of Cu and Zn remarkably improves Zn reversibility of 3D nanoporous Zn electrodes for potential use as high-performance AR-ZMB anode materials.As a result of the zincophilic ZnxCuy alloy shell guiding uniform Zn deposition with a zero nucleation overpotential and facilitating Zn stripping via the ZnxCuy/Zn galvanic couples,the self-supported nanoporous ZnxCuy/Zn electrodes exhibit superior dendrite-free Zn stripping/plating behaviors in ambient aqueous electrolyte,with ultralow polarizations under current densities up to 50 mA cm^(‒2),exceptional stability for 1900 h and high Zn utilization.This enables AR-ZMB full cells constructed with nanoporous ZnxCuy/Zn anode and K_(z)MnO_(2)cathode to achieve specific energy of as high as~430 Wh kg^(‒1)with~99.8%Coulombic efficiency,and retain~86%after long-term cycles for>700 h.
基金The National Natural Science Foundation of China provided funding for this project(Nos.31971491,32201371).
文摘Seedling stage has long been recognized as the bottleneck of forest regeneration,and the biotic and abiotic processes that dominate at seedling stage largely affect the dynamics of forest.Seedlings might be particularly vulnerable to climate stress,so elucidating the role of interannual climate variation in fostering community dynamics is crucial to understanding the response of forest to climate change.Using seedling survival data of 69 woody species collected for five consecutive years from a 25-ha permanent plot in a temperate deciduous forest,we identified the effects of biotic interactions and habitat factors on seedling survival,and examined how those effects changed over time.We found that interannual climate variations,followed by biotic interactions and habitat conditions,were the most significant predictors of seedling survival.Understory light showed a positive impact on seedling mortality,and seedling survival responded differently to soil and air temperature.Effects of conspecific neighbor density were significantly strengthened with the increase of maximum air temperature and vapor pressure deficits in the growing season,but were weakened by increased maximum soil temperature and precipitation in the non-growing season.Surprisingly,seedling survival was strongly correlated with interannual climate variability at all life stages,and the strength of the correlation increased with seedling age.In addition,the importance of biotic and abiotic factors on seedling survival differed significantly among species-trait groups.Thus,the neighborhood-mediated effects on mortality might be significantly contributing or even inverting the direct effects of varying abiotic conditions on seedling survival,and density-dependent effects could not be the only important factor influencing seedling survival at an early stage.
基金This research was supported in part by the Hunan Province’s Strategic and Emerging Industrial Projects under Grant 2018GK4035in part by the Hunan Province’s Changsha Zhuzhou Xiangtan National Independent Innovation Demonstration Zone projects under Grant 2017XK2058+1 种基金in part by the National Natural Science Foundation of China under Grant 61602171in part by the Scientific Research Fund of Hunan Provincial Education Department under Grant 17C0960 and 18B037.
文摘Currently,the top-rank-k has been widely applied to mine frequent patterns with a rank not exceeding k.In the existing algorithms,although a level-wise-search could fully mine the target patterns,it usually leads to the delay of high rank patterns generation,resulting in the slow growth of the support threshold and the mining efficiency.Aiming at this problem,a greedy-strategy-based top-rank-k frequent patterns hybrid mining algorithm(GTK)is proposed in this paper.In this algorithm,top-rank-k patterns are stored in a static doubly linked list called RSL,and the patterns are divided into short patterns and long patterns.The short patterns generated by a rank-first-search always joins the two patterns of the highest rank in RSL that have not yet been joined.On the basis of the short patterns satisfying specific conditions,the long patterns are extracted through level-wise-search.To reduce redundancy,GTK improves the generation method of subsume index and designs the new pruning strategies of candidates.This algorithm also takes the use of reasonable pruning strategies to reduce the amount of computation to improve the computational speed.Real datasets and synthetic datasets are adopted in experiments to evaluate the proposed algorithm.The experimental results show the obvious advantages in both time efficiency and space efficiency of GTK.
基金supported by the National Natural Science Foundation of China(Nos.31971491,31770517)the Meituan Qingshan Special Commonweal Fund of China Environmental Protection Foundation(CEPFQS202169-20)。
文摘Biodiversity conservation has long been a subject of extreme interest to community ecologists,with a particular focus on exploring the underlying causes of species diversity based on niche and neutral theories.This study aims to identify the potential determinants of species diversity in a deciduous broad-leaved forest in the transitional region from subtropical to temperate climate in China.We collected woody plant data and environmental variables in a fully mapped 25-ha permanent forest plot,partitioned the beta-diversity into local contributions(LCBD)and species contributions(SCBD),and then applied multivariate linear regression analysis to test the effects of biotic and abiotic factors on alpha-diversity,LCBD,and SCBD.We used variation partitioning in combination with environmental variables and spatial distance to determine the contribution of environment-related variations versus spatial variations.Our results showed that the indices of alpha-diversity(i.e.,species abundance and richness)were positively correlated with soil available phosphorus(P)and negatively with slope.For the betadiversity,environment and space together explained nearly half of the variations in community composition.Approximately 60%of the variation of LCBD in the understory layer,40%in the substory layer,and 29%in the canopy layer were jointly explained by topographic,soil and biological variables,with biotic factors playing a dominant role in determining the beta-diversity.Species abundance accounted for a large proportion of the variations in SCBD in each vertical stratum,and niche position(NP)was the ecological trait that significantly affected the variations in SCBD in the substory and canopy layers.Our findings help to gain better understanding on how species diversity in forest ecosystem responds to environmental conditions and how it is influenced by biotic factors and ecological traits of species.
基金the National Natural Science Foundation of China(Nos.22271235,22071198)the“Pioneer”and“Leading Goose”R&D Program of Zhejiang(No.2022SDXHDX0006)the Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(No.2020R01004)for research support。
文摘Mannich-type reactions are a widely used method for the synthesis of amines due to the readily availability of nucleophiles and electrophiles.However,the inclusion of alkylarenes instead of active carbon pronucleophiles such as aldehydes and ketones in these addition reactions has been a challenge due to the inherent difficulty of benzylic deprotonation.In this study,we present a novel approach for the construction of N-sulfonyl amines via rhodium-catalyzed addition of unbiased benzylic C–H bonds to cyclic N-sulfonyl ketamines throughπ-coordination.This strategy enables the synthesis of a diverse range of N-sulfonyl amines,and subsequent diversification of the addition products showcases the synthetic potential of this protocol.
基金This work was financially supported by the Basic Science Center Program for Ordered Energy Conversion of the National Natural Science Foundation of China(51888103)the National Key R&D Program of China(2021YFF0500700)Jiangsu Natural Science Foundation Project(BE2022024 and BK20202008).
文摘Solar-driven CO_(2)-to-fuel conversion assisted by another major greenhouse gas CH_(4)is promising to concurrently tackle energy shortage and global warming problems.However,current techniques still suffer from drawbacks of low efficiency,poor stability,and low selectivity.Here,a novel nanocomposite composed of interconnected Ni/MgAlOx nanoflakes grown on SiO_(2)particles with excellent spatial confinement of active sites is proposed for direct solar-driven CO_(2)-to-fuel conversion.An ultrahigh light-to-fuel efficiency up to 35.7%,high production rates of H_(2)(136.6 mmol min^(-1)g^(-1))and CO(148.2 mmol min^(-1)g^(-1)),excellent selectivity(H_(2)/CO ratio of 0.92),and good stability are reported simultaneously.These outstanding performances are attributed to strong metal-support interactions,improved CO_(2)absorption and activation,and decreased apparent activation energy under direct light illumination.MgAlO_(x)@SiO_(2)support helps to lower the activation energy of CH^(*) oxidation to CHO^(*) and improve the dissociation of CH_(4)to CH_(3)^(*) as confirmed by DFT calculations.Moreover,the lattice oxygen of MgAlO_(x) participates in the reaction and contributes to the removal of carbon deposition.This work provides promising routes for the conversion of greenhouse gasses into industrially valuable syngas with high efficiency,high selectivity,and benign sustainability.
基金funded by the National Key R&D Program of China(2021YFE0112400 and 2023YFF1304303)the National Natural Science Foundation of China(32361143870 and 32101315)。
文摘The response of N_(2)O emissions to nitrogen(N)addition is usually positive,but its response to phosphorus(P)addition varies,and the underlying mechanisms for the changes in N_(2)O emissions remain unclear.We conducted field studies to examine the response of N_(2)O emissions to N and P addition over two years in three typical alpine grasslands,alpine meadow(AM),alpine steppe(AS),and alpine cultivated grassland(CG)on the Qinghai-Tibet Plateau(QTP).Our results showed consistent increases in N_(2)O emissions under N addition alone or with P addition,and insignificant change in N_(2)O emissions under P addition alone in all three grasslands.N addition increased N_(2)O emissions directly in AM,by lowering soil pH in AS,and by lowering abundance of denitrification genes in CG.N and P co-addition increased N_(2)O emissions in AM and AS but only showed an interactive effect in AM.P addition enhanced the increase in N_(2)O emissions caused by N addition mainly by promoting plant growth in AM.Overall,our results illustrate that short-term P addition cannot alleviate the stimulation of N_(2)O emissions by N deposition in alpine grassland ecosystems,and may even further stimulate N_(2)O emissions.
基金This work was supported by funding from the Fujian Provincial Maternity and Children Hospital(No.YCXM19-29)the Fujian Natural Science Foundation(No.2019J01511 and No.2020Y0067)the Health Research Project of the Department of Finance(Fujian finance refers to[2019]No.827).
文摘This study analyzed the effects of male age and abstinence time on semen quality and explored the best abstinence time for Chinese males among different age groups.Semen parameters,including sperm kinetics,morphology,and DNA fragmentation index(DFI),were reviewed from 2952 men.Samples were divided into six age groups(≤25 years,26–30 years,31–35 years,36–40 years,41–45 years,and>45 years)and were divided into six groups according to different abstinence time(2 days,3 days,4 days,5 days,6 days,and 7 days).The differences in semen quality between the groups were compared,and the effect of age and abstinence time on semen quality was analyzed.Significant differences were observed in semen volume,progressive motility(PR),and DFI among the age groups(all P<0.05),and no significant differences were observed in sperm morphological parameters(all P>0.05).There were significant differences in semen volume,PR,and DFI among different abstinence time groups(all P<0.05)and no significant differences in sperm morphological parameters(all P>0.05).Pearson analysis showed that male age and abstinence time were both significantly correlated with sperm kinetics and DFI(both P<0.05),while no significant correlation was found with sperm morphological parameters(all P>0.05).The box plots and histograms of men’s age,abstinence time,and semen quality show that most semen quality parameters differ significantly between the 2 days and 7 days abstinence groups and other groups at different ages.Except for the sperm morphology parameters,sperm kinetic parameters and sperm DFI are linearly related to male age and abstinence time.
基金supported by the National Natural Science Foundation of China (Nos. 51871107, 52130101, 51631004)Top-notch Young Talent Program of China (W02070051)+2 种基金Chang Jiang Scholar Program of China (Q2016064)the Program for JLU Science and Technology Innovative Research Team (JLUSTIRT, 2017TD-09)the Fundamental Research Funds for the Central Universities, the Program for Innovative Research Team (in Science and Technology) in University of Jilin Province。
文摘Aqueous multivalent-metal-ion intercalation chemistries hold genuine promise to develop safe and powerful microbatteries for potential use in many miniaturized electronics.However,their development is beset by state-of-the-art electrode materials having practical capacities far below their theoretical values.Here we demonstrate that high compatibility between layered transition-metal oxide hosts and hydrated cation vips substantially boost their multi-electron-redox reactions to offer higher capacities and rate capability,based on typical bipolar vanadium oxides preintercalated with hydrated cations(M_(x)V_(2)O_(5)).When seamlessly integrated on Au current microcollectors with a three-dimensional bicontinuous nanoporous architecture that offers high pathways of electron transfer and ion transport,the constituent Zn_(x)V_(2)O_(5) exhibits specific capacity of as high as∼527 mAh g^(−1) at 5 mV s^(−1) and retains∼300 mAh g^(−1) at 200 mV s^(−1) in 1 M ZnSO_(4) aqueous electrolyte,outperforming the M_(x)V_(2)O_(5)(M=Li,Na,K,Mg).This allows aqueous rechargeable zinc-ion microbatteries constructed with symmetric nanoporous Zn_(x)V_(2)O_(5)/Au interdigital microelectrodes as anode and cathode to show high-density energy of∼358 mWh cm^(−3)(a value that is forty-fold higher than that of 4 V/500μAh Li thin film battery)at high levels of power delivery.
基金This work was supported by the National Natural Science Foundation of China(Nos.51871107 and 51631004)the Top-Notch Young Talent Program of China(W02070051)+3 种基金the Chang Jiang Scholar Program of China(Q2016064)the Program for JLU Science and Technology Innovative Research Team(JLUSTIRT,2017TD-09)the Fundamental Research Funds for the Central Universitiesthe Program for Innovative Research Team(in Science and Technology)in University of Jilin Province.
文摘Designing highly active and robust platinum-free electrocatalysts for hydrogen evolution reaction is vital for large-scale and efficient production of hydrogen through electrochemical water splitting.Here,we report nonprecious intermetallic Cu_(5)Zr clusters that are in situ anchored on hierarchical nanoporous copper(NP Cu/Cu_(5)Zr)for efficient hydrogen evolution in alkaline medium.By virtue of hydroxygenated zirconium atoms activating their nearby Cu-Cu bridge sites with appropriate hydrogenbinding energy,the Cu_(5)Zr clusters have a high electrocatalytic activity toward the hydrogen evolution reaction.Associated with unique architecture featured with steady and bicontinuous nanoporous copper skeleton that facilitates electron transfer and electrolyte accessibility,the self-supported monolithic NP Cu/Cu_(5)Zr electrodes boost violent hydrogen gas release,realizing ultrahigh current density of 500mAcm^(-2) at a low potential of-280mV versus reversible hydrogen electrode,with exceptional stability in 1M KOH solution.The electrochemical properties outperform those of state-of-the-art nonprecious metal electrocatalysts and make them promising candidates as electrodes in water splitting devices.
基金the Open Project Program of Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica(No.JKLPSE201501)the Open Project of Chinese Materia Medica First-Class Discipline of Nanjing University of Chinese Medicine(No.2020YLXK20)the Science and Technology Development Foundation of Nanjing Medical University(No.NMUB2019186).
文摘Background and Aims:Oxaliplatin is widely used in can-cer chemotherapy with adverse effects such as liver toxicity.Magnesium isoglycyrrhizinate(MgIG)has hepatoprotective effects,but the underlying mechanism remains elusive.The study’s aim was to investigate the mechanism underlying the hepatoprotective effects of MgIG against oxaliplatin-induced liver injury.Methods:A xenografted colorectal cancer mouse model was established with MC38 cells.Mice were given ox-aliplatin(6 mg/kg/week)for 5 weeks to mimic oxaliplatin-induced liver injury in vivo.LX-2 human hepatic stellate cell s(HSCs)were employed for in vitro studies.Serological tests,hematoxylin and eosin staining,oil red O staining and trans-mission electron microscopy were used for histopathological examinations.Real-time PCR,western blotting,immuno-fluorescence and immunohistochemical staining were used to determine Cx43 mRNA or protein levels.Flow cytometry was used to assay reactive oxygen species(ROS)and mito-chondrial membrane.Short hairpin RNA targeting Cx43 was lentivirally transduced in LX-2 cells.Ultra-high performance liquid chromatography-tandem mass spectrometry was used to determine MgIG and metabolite concentration.Results:MgIG(40 mg/kg/day)treatment significantly reduced se-rum aspartate transaminase(AST)and alanine transami-nase(ALT)levels in the mouse model,and alleviated liver pathological changes,including necrosis,sinusoidal expan-sion,mitochondrial damage,and fibrosis.MgIG reduced the abnormal expression of Cx43 in the mitochondria and nuclei of HSCs.MgIG inhibited the activation of HSCs via reducing ROS generation,mitochondrial dysfunction,and N-cadherin transcription.MgIG’s inhibition of HSCs activation was abol-ished after knockdown of Cx43 in LX-2 cells.Conclusions:Cx43 mediated MgIG’s hepatoprotective effects against ox-aliplatin-induced toxicity.
基金supported by the“Pioneer”and“Leading Goose”R&D Program of Zhejiang(2022SDXHDX0006)the Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(2020R01004)。
文摘This article demonstrates a catalytic method for C(aryl)-C(alkyl) bond functionalization of N-sulfonyl amines. A cobalt(III)catalyst was used to cleave the C-C bond via β-carbon elimination, providing a metallacycle intermediate. Subsequent allylation,amidation, or alkenylation of the intermediate led to divergent conversions in the presence of diverse coupling partners. when the coupling partner was a diene, an insertion-type functionalization was realized with an exclusive 1,3-regioselectivity, in which both of the fragments derived from N-sulfonyl amines were utilized.
基金the National Natural Science Foundation of China(No.21572075)the 111 Project B17019+1 种基金the Research Project of Hubei Provincial Department of Education(No.Q20192806)the Doctoral Research Fund of Hubei University of Science and Technology(No.BK201808).
文摘A simple one pot synthesis of polysubstituted pyrroles via ketenimine formation/Ag(l)-catalyzed alkyne cycloisomerisation has been developed.The easily accessible phosphorane ylide derivatives reacted with isocyanates,producing highly active ketenimines that were then treated with amines,which afforded substituted pyrroles by a S-exo-dig cyclization/isomerization in the presence of a Ag(l)catalyst in good overall yields.
