Accurate initial soil conditions play a crucial role in simulating soil hydrothermal and surface energy fluxes in land surface process modeling.This study emphasized the influence of the initial soil temperature(ST)an...Accurate initial soil conditions play a crucial role in simulating soil hydrothermal and surface energy fluxes in land surface process modeling.This study emphasized the influence of the initial soil temperature(ST)and soil moisture(SM)conditions on a land surface energy and water simulation in the permafrost region in the Tibetan Plateau(TP)using the Community Land Model version 5.0(CLM5.0).The results indicate that the default initial schemes for ST and SM in CLM5.0 were simplistic,and inaccurately represented the soil characteristics of permafrost in the TP which led to underestimating ST during the freezing period while overestimating ST and underestimating SLW during the thawing period at the XDT site.Applying the long-term spin-up method to obtain initial soil conditions has only led to limited improvement in simulating soil hydrothermal and surface energy fluxes.The modified initial soil schemes proposed in this study comprehensively incorporate the characteristics of permafrost,which coexists with soil liquid water(SLW),and soil ice(SI)when the ST is below freezing temperature,effectively enhancing the accuracy of the simulated soil hydrothermal and surface energy fluxes.Consequently,the modified initial soil schemes greatly improved upon the results achieved through the long-term spin-up method.Three modified initial soil schemes experiments resulted in a 64%,88%,and 77%reduction in the average mean bias error(MBE)of ST,and a 13%,21%,and 19%reduction in the average root-mean-square error(RMSE)of SLW compared to the default simulation results.Also,the average MBE of net radiation was reduced by 7%,22%,and 21%.展开更多
In this study,we developed a novel on-line solid phase extraction(SPE)-ultra-high-performance liquid chromatography tandem mass spectrometry(UHPLC-MS/MS)-based analytical method for simultaneously quantifying 12 illic...In this study,we developed a novel on-line solid phase extraction(SPE)-ultra-high-performance liquid chromatography tandem mass spectrometry(UHPLC-MS/MS)-based analytical method for simultaneously quantifying 12 illicit drugs and metabolites(methamphetamine,amphetamine,morphine,codeine,6-monoacetylmorphine,benzoylecgonine,3,4-methylenedioxymethamphetamine,3,4-methylenedioxyamphetamine,cocaine,ketamine,norketamine,and methcathinone)and cotinine(COT)in wastewater samples.The analysis was performed by loading 2 m L of the sample onto an Oasis hydrophilic-lipophilic balance cartridge and using a cleanup step(5%methanol)to eliminate interference with a total run time of 13 min.The isotope-labeled internal standard method was used to quantify the target substances and correct for unavoidable losses and matrix effects during the on-line SPE process.Typical analytical characteristics used for method validation were sensitivity,linearity,precision,repeatability,recovery,and matrix effects.The limit of detection(LOD)and limit of quantification(LOQ)of each target were set at 0.20 ng/L and 0.50 ng/L,respectively.The linearity was between 0.5 ng/L and250 ng/L,except for that of COT.The intra-and inter-day precisions were<10.45%and 25.64%,respectively,and the relative recovery ranged from 83.74%to 162.26%.The method was used to analyze various wastewater samples from 33 cities in China,and the results were compared with the experimental results of identical samples analyzed using off-line SPE.The difference rate was between 19.91%and-20.44%,and the error range could be considered acceptable.These findings showed that on-line SPE is a suitable alternative to off-line SPE for the analysis of illicit drugs in samples.展开更多
Korean pine(Pinus koraiensis Siebold&Zucc.)in Northeastern China has been genetically improved to increase seed yields in addition to timber.To assess seed yield variability and select highly productive clones,14 ...Korean pine(Pinus koraiensis Siebold&Zucc.)in Northeastern China has been genetically improved to increase seed yields in addition to timber.To assess seed yield variability and select highly productive clones,14 cone,seed and nut traits were measured and analyzed.Variance analysis showed that all clones were signifi cantly different in various traits(P<0.01).Phenotypic coeffi cients of variation and repeatability of traits ranged from 9.1 to 34.4%and from 27.5 to 97.7%,respectively.Except for the cone layer and cone seed numbers,the other traits were positively or negatively correlated.Three principal components were identifi ed.Seed and nut traits were the most important traits in the fi rst principal component,and cone traits more important in the second.Using correlation and principal component analyses,cone number and other traits were selected to evaluate materials.Twenty-two clones were selected using a selection rate of 10%based on cone number independently or other combined traits.The genetic gain for diff erent traits ranged from 6.2 to 24.3%.The selected elite clones can supply seedlings for reforestation and the selection method can provide a theoretical basis for selection in other conifer species.展开更多
Fiber reinforced composite frame structure is an ideal lightweight and large-span structure in the fields of aerospace,satellite and wind turbine.Natural fundamental frequency is one of key indicators in the design re...Fiber reinforced composite frame structure is an ideal lightweight and large-span structure in the fields of aerospace,satellite and wind turbine.Natural fundamental frequency is one of key indicators in the design requirement of the composite frame since structural resonance can be effectively avoided with the increase of the fundamental frequency.Inspired by the concept of integrated design optmization of composite frame structures and materials,the design optimization for the maximum structural fundamental frequency of fiber reinforced frame structures is proposed.An optimization model oriented at the maximum structural fundamental frequency under a composite material volume constraint is established.Two kinds of independent design variables are optimized,in which one is variables represented structural topology,the other is variables of continuous fiber winding angles.Sensitivity analysis of the frequency with respect to the two kinds of independent design variables is implemented with the semi-analytical sensitivity method.Some representative examples in the manuscript demonstrate that the integrated design optimization of composite structures can effectively explore coupled effects between structural configurations and material properties to increase the structural fundamental frequency.The proposed integrated optimization model has great potential to improve composite frames structural dynamic performance in aerospace industries.展开更多
Semiconducting piezoelectricα-In_(2)Se_(3) and 3R MoS_(2) have attracted tremendous attention due to their unique electronic properties.Artificial van der Waals(vdWs)hetero-structures constructed withα-In_(2)Se_(3)a...Semiconducting piezoelectricα-In_(2)Se_(3) and 3R MoS_(2) have attracted tremendous attention due to their unique electronic properties.Artificial van der Waals(vdWs)hetero-structures constructed withα-In_(2)Se_(3)and 3R MoS_(2)flakes have shown promising applications in optoelectronics and photocatal-ysis.Here,we present the first flexibleα-In_(2)Se_(3)/3R MoS_(2)vdWs p-n heterojunction devices for photodetection from the visible to near infrared region.These heterojunction devices exhibit an ultrahigh photoresponsivity of 2.9×10^(3)A W^(−1) and a substantial specific detectivity of 6.2×10^(10) Jones under a compressive strain of−0.26%.The photocurrent can be increased by 64%under a tensile strain of+0.35%,due to the heterojunction energy band modulation by piezoelectric polarization charges at the hetero-junction interface.This work demonstrates a feasible approach to enhancement of α-In_(2)Se_(3)/3R MoS_(2) photoelectric response through an appropriate mechanical stimulus.展开更多
The simulation of soil temperature on the Tibetan Plateau(TP) plays a dominant role in the performance of both global climate and numerical weather forecast models. To improve the simulation of soil temperature on the...The simulation of soil temperature on the Tibetan Plateau(TP) plays a dominant role in the performance of both global climate and numerical weather forecast models. To improve the simulation of soil temperature on the TP, the Johansen soil thermal conductivity parameterization scheme was introduced into Community Land Model 3.5(CLM3.5) and Regional Climatic Model 4(Reg CM4). The improved CLM3.5 and Reg CM4-CLM were utilized to conduct offline and regional simulation experiments on the TP. Comparison of the new and old schemes revealed that CLM3.5 provides high thermal conductivity parameters of mineral soil solid on the TP. The Johansen scheme is more practical for the TP than the soil thermal conductivity parameterization in CLM3.5. The simulation of soil temperature and liquid water content was improved in offline experiment. The improved parameterization scheme can also reduce the simulation error of soil temperature in winter throughout the entire TP.展开更多
In order to improve the heat dissipation capability of motor controller for new energy vehicles,the water cooled radiator with multiple channels is optimized in this paper.The heat conduction between the heat source I...In order to improve the heat dissipation capability of motor controller for new energy vehicles,the water cooled radiator with multiple channels is optimized in this paper.The heat conduction between the heat source IGBT and the radiator,the convective heat transfer between the radiator and the coolant,the mechanical strength and the manufacturing cost are comprehensively considered during the optimization process.The power loss and thermal resistance of the IGBT unit are calculated at first,and finite element model of the radiator is established.On this basis,multi-physics coupling analysis of the water cooled radiator is carried out.Secondly,the sensitivity analysis is applied to verify the influence of structural parameters on the heat dissipation performance of the radiator system.The influence of coolant inlet velocity v,number of cooling ribs n,height of radiator ribs H on the maximum temperature rise T,the temperature difference ΔT between phase U and W,and the coolant pressure lossΔP are analyzed in depth,and the optimal range of the structural parameters for heat dissipation is obtained.Finally,an experimental platform was set up to verify the performance of the proposed structure of water cooled radiator for motor controller of new energy vehicle.The results show that the heat dissipation capability of the proposed radiator is improved compared with the initial design.展开更多
Genetic parameters were evaluated for growth and cone characteristics(tree height,diameter at breast height,volume,cone number,thousand seeds weight and single cone seeds weight)on 86 half-sib families of Pinus koraie...Genetic parameters were evaluated for growth and cone characteristics(tree height,diameter at breast height,volume,cone number,thousand seeds weight and single cone seeds weight)on 86 half-sib families of Pinus koraiensis aged 31 years.Analyses of variance revealed significant differences(p<0.001)in all growth and cone traits among families while no significant differences were detected among blocks and the interaction between blocks and families.The average family values for growth traits were 17.22 m,8.67 cm and 0.43 m^(3) for tree height,diameter at breast height and volume,respectively.The average cone number,thousand seeds weight and single cone seeds weight were 17.57,748.91 g and 77.25 g,respectively.Genotypic additive variance and phenotypic variances ranged from 0.00009 to 3.820 and from 0.0005 to 23.066,while genotypic and phenotypic coefficients of variation ranged from 2.693%to 37.196%and 4.963%to 60.595%,respectively.Heritability at the individual and family level ranged from 0.152 to 0.215 and 0.611 to 0.862,respectively.Growth traits were significantly positively correlated with each other,but cone traits showed a weak correlation with growth traits.Based on 10% selection rate,nine families each were selected as elite materials in terms of high performance in volume and cone numbers,with 22.16%and 43.82%genetic gain in volume and cone number,respectively.These results provide beneficial information to select excellent families and establish orchards of P.koraiensis from improved seeds.展开更多
Background: Human Cytomegalovirus(HCMV) infections can be found throughout the body, especially in epithelial tissue. Animal model was established by inoculation of HCMV(strain AD-169) or coinoculation with Hepatitis ...Background: Human Cytomegalovirus(HCMV) infections can be found throughout the body, especially in epithelial tissue. Animal model was established by inoculation of HCMV(strain AD-169) or coinoculation with Hepatitis E virus(HEV) into the ligated sacculus rotundus and vermiform appendix in living rabbits. The specimens were collected from animals sacrificed 1 and a half hours after infection.Results: The virus was found to be capable of reproducing in these specimens through RT-PCR and Western-blot.Severe inflammation damage was found in HCMV-infected tissue. The viral protein could be detected in high amounts in the mucosal epithelium and lamina propria by immunohistochemistry and immunofluorescense.Moreover, there are strong positive signals in lymphocytes, macrophages, and lymphoid follicles. Quantitative statistics indicate that lymphocytes among epithlium cells increased significantly in viral infection groups.Conclusions: The results showed that HCMV or HEV + HCMV can efficiently infect in rabbits by vivo ligated intestine loop inoculation. The present study successfully developed an infective model in vivo rabbit ligated intestinal Loop for HCMV pathogenesis study. This rabbit model can be helpful for understanding modulation of the gut immune system with HCMV infection.展开更多
Soil and climatic conditions are known to have close associations with plant morphological and stoichiometric traits at a regional scale along latitudinal gradients;however,how latitude drives biotic and abiotic facto...Soil and climatic conditions are known to have close associations with plant morphological and stoichiometric traits at a regional scale along latitudinal gradients;however,how latitude drives biotic and abiotic factors affecting plant nutrient acquisition to accommodate environmental nutrient deficiency remains unclear.We quantified soil,root,leaf,and leaf litter nitrogen(N)and phosphorus(P)concentrations to determine the potentially limiting nutrient and the simultaneous responses of root capture and leaf resorption to nutrient deficiency in seven Quercus acutissima forests across the North–South Transect of Eastern China.The results showed that the mean leaf and root N:P ratios in Q.acutissima were 21.58 and 20.23,respectively,which markedly exceeded the P limitation threshold of 16 for terrestrial plants.The mean leaf litter N and P were 10.63 mg/g and 0.51 mg/g,respectively,indicating that P resorption proficiency was relatively higher than N resorption proficiency.N displayed higher stoichiometric homeostasis than P in the leaf.The leaf and root N:P ratios showed a quadratic variation that first decreased and then increased as latitude increased,whereas the phosphorus resorption efficiency and root-soil accumulation factor of P displayed the opposite trend.Partial least square path modeling(PLS-PM)analysis demonstrated that root nutrient capture and leaf nutrient resorption were regulated by different influential factors.Overall,these findings provide new insights into plant strategies to adapt to environmental nutrient deficiency,as well as the scientific basis for predicting the spatial and temporal patterns of nutrient acquisition in the context of climate change.展开更多
After the outbreak of COVID-19,the interaction of infectious disease systems and social systems has challenged traditional infectious disease modeling methods.Starting from the research purpose and data,researchers im...After the outbreak of COVID-19,the interaction of infectious disease systems and social systems has challenged traditional infectious disease modeling methods.Starting from the research purpose and data,researchers im-proved the structure and data of the compartment model or used agents and artificial intelligence based models to solve epidemiological problems.In terms of modeling methods,the researchers use compartment subdivi-sion,dynamic parameters,agent-based model methods,and artificial intelligence related methods.In terms of factors studied,the researchers studied 6 categories:human mobility,nonpharmaceutical interventions(NPIs),ages,medical resources,human response,and vaccine.The researchers completed the study of factors through modeling methods to quantitatively analyze the impact of social systems and put forward their suggestions for the future transmission status of infectious diseases and prevention and control strategies.This review started with a research structure of research purpose,factor,data,model,and conclusion.Focusing on the post-COVID-19 infectious disease prediction simulation research,this study summarized various improvement methods and analyzes matching improvements for various specific research purposes.展开更多
Introduction:High-resolution data is essential for understanding the complexity of the relationship between the spread of coronavirus disease 2019(COVID-19),resident behavior,and interventions,which could be used to i...Introduction:High-resolution data is essential for understanding the complexity of the relationship between the spread of coronavirus disease 2019(COVID-19),resident behavior,and interventions,which could be used to inform policy responses for future prevention and control.Methods:We obtained high-resolution human mobility data and epidemiological data at the community level.We propose a metapopulation Susceptible-Exposed-Presymptomatic-Infectious-Removal(SEPIR)compartment model to utilize the available data and explore the internal driving forces of COVID-19 transmission dynamics in the city of Wuhan.Additionally,we will assess the effectiveness of the interventions implemented in the smallest administrative units(subdistricts)during the lockdown.Results:In the Wuhan epidemic of March 2020,intra-subdistrict transmission caused 7.6 times more infections than inter-subdistrict transmission.After the city was closed,this ratio increased to 199 times.The main transmission path was dominated by population activity during peak evening hours.Discussion:Restricting the movement of people within cities is an essential measure for controlling the spread of COVID-19.However,it is difficult to contain intra-street transmission solely through citywide mobility restriction policies.This can only be accomplished by quarantining communities or buildings with confirmed cases,and conducting mass nucleic acid testing and enforcing strict isolation protocols for close contacts.展开更多
The existing moving box mechanism pot seedling transplanting machine on the market moves too fast when the picked seedling is collected,which negatively impacts the seedling picking performance.In order to improve the...The existing moving box mechanism pot seedling transplanting machine on the market moves too fast when the picked seedling is collected,which negatively impacts the seedling picking performance.In order to improve the performance,two types of variable speed continuous moving box schemes were designed in this study.The first scheme was to apply a spiral-gear moving box spiral shaft with sine curve characteristics in the box moving mechanism,whereas the second one was to change the circular gear in the moving box into an elliptical gear with a speed shifting transmission mechanism.The working mechanism of the mechanical structure was analyzed,and the kinematic model was established.A dynamic analysis of the slider mechanism was performed.A virtual prototype was established according to agronomic parameters,and the virtual prototype experiments were conducted in ADAMS.The physical prototype and the high-speed photography experiment were performed on the test bench of a transplanting machine frame.The theoretical analysis,virtual prototype and physical prototype test results were consistent,which verified the validity of the theoretical model,virtual prototype and physical prototype and ensured the feasibility of the system.展开更多
1 Introduction Deep learning has obtained a great success in computing technologies and has been afiliated to people's lives insepa-rably recent years.Nowadays,the most common approach to deploy these deep learnin...1 Introduction Deep learning has obtained a great success in computing technologies and has been afiliated to people's lives insepa-rably recent years.Nowadays,the most common approach to deploy these deep learning models is to collect the users data and train them in central servers.Nevertheless,the users data might be inevitably undermined during the process of col-lection and uploading,and users sensitive information might be exposed to danger.Aiming at reducing the risk of privacy leakage,Google proposed federated learning,which has been successfully applied to several applications,e.g.,data alliance among enterprises[1],next word prediction in Gboard[2],etc.展开更多
Xenobiotic receptors are traditionally defined as xenobiotic chemical-sensing receptors,the activation of which transcriptionally regulates the expression of enzymes and transporters involved in the metabolism and dis...Xenobiotic receptors are traditionally defined as xenobiotic chemical-sensing receptors,the activation of which transcriptionally regulates the expression of enzymes and transporters involved in the metabolism and disposition of xenobiotics.Emerging evidence suggests that“xenobiotic receptors”also have diverse endobiotic functions,including their effects on lipid metabolism and energy metabolism.Dyslipidemia is a major risk factor for cardiovascular disease,diabetes,obesity,metabolic syndrome,stroke,nonalcoholic fatty liver disease(NAFLD),and nonalcoholic steatohepatitis(NASH).Understanding the molecular mechanism by which transcriptional factors,including the xenobiotic receptors,regulate lipid homeostasis will help to develop preventive and therapeutic approaches.This review describes recent advances in our understanding the atypical roles of three xenobiotic receptors:aryl hydrocarbon receptor(AhR),pregnane X receptor(PXR),and constitutive androstane receptor(CAR),in metabolic disorders,with a particular focus on their effects on lipid and glucose metabolism.Collectively,the literatures suggest the potential values of AhR,PXR and CAR as therapeutic targets for the treatment of NAFLD,NASH,obesity and diabetes,and cardiovascular diseases.展开更多
Background BRCA1/2 mutations have been shown to be associated with the development of many solid tumors including endometrial cancer(EC).The objectives of this study are to analyze the association between BRCA1/2 muta...Background BRCA1/2 mutations have been shown to be associated with the development of many solid tumors including endometrial cancer(EC).The objectives of this study are to analyze the association between BRCA1/2 mutational status and clinicopathological characteristics as well as outcomes in EC patients.Methods 510 eligible EC patients from the Cancer Genome Atlas database were included in the study.The association between clinicopathological characteristics and different BRCA1/2 mutational status was compared and analyzed.Analyses of the impact of BRCA mutations on survival in EC patients was conducted using Kaplan-Meier survival analyses and Cox regressions.In order to control confounding bias between groups,propensity score matching method was used.Results Among the eligible patients,11(2.2%)harbored BRCA1 mutation,43(8.4%)harbored BRCA2 mutation,and 36(7.1%)harbored both.Body mass index,rates of hypertension history,proportion of non-endometrioid histology and rates of positive peritoneal cytology were lower in patients with BRCA1/2 mutations compared with the group of wild-type counterpart(p=0.020,0.048,0.001 and 0.012,respectively).Patients with BRCA1/2 mutations showed longer overall(OS)and recurrence-free survival(RFS)(in Kaplan-Meier analyses,p<0.001 and p=0.004,respectively;in Cox regressions,p=0.001 and 0.007,respectively).Further analyses showed that the impact of BRCA mutations on survival was significant only in patients with high-grade endometrioid EC.Based on the cohorts generated after propensity score matching,in high-grade endometrioid EC patients,the influence of BRCA1/2 mutations remained significant on OS,but not on RFS(p=0.003 and 0.057 in Kaplan-Meier analyses,p=0.020 and 0.071 in Cox regressions).Conclusion BRCA1/2 mutations are associated with better survival in patients with high grade endometrioid EC,indicating the value of BRCA testing in EC clinical management.展开更多
基金the National Natural Science Foundation of China(Grant No.U20A2081)West Light Foundation of the Chinese Academy of Sciences(Grant No.xbzg-zdsys-202102)the Second Tibetan Plateau Scientific Expedition and Research(STEP)Project(Grant No.2019QZKK0105).
文摘Accurate initial soil conditions play a crucial role in simulating soil hydrothermal and surface energy fluxes in land surface process modeling.This study emphasized the influence of the initial soil temperature(ST)and soil moisture(SM)conditions on a land surface energy and water simulation in the permafrost region in the Tibetan Plateau(TP)using the Community Land Model version 5.0(CLM5.0).The results indicate that the default initial schemes for ST and SM in CLM5.0 were simplistic,and inaccurately represented the soil characteristics of permafrost in the TP which led to underestimating ST during the freezing period while overestimating ST and underestimating SLW during the thawing period at the XDT site.Applying the long-term spin-up method to obtain initial soil conditions has only led to limited improvement in simulating soil hydrothermal and surface energy fluxes.The modified initial soil schemes proposed in this study comprehensively incorporate the characteristics of permafrost,which coexists with soil liquid water(SLW),and soil ice(SI)when the ST is below freezing temperature,effectively enhancing the accuracy of the simulated soil hydrothermal and surface energy fluxes.Consequently,the modified initial soil schemes greatly improved upon the results achieved through the long-term spin-up method.Three modified initial soil schemes experiments resulted in a 64%,88%,and 77%reduction in the average mean bias error(MBE)of ST,and a 13%,21%,and 19%reduction in the average root-mean-square error(RMSE)of SLW compared to the default simulation results.Also,the average MBE of net radiation was reduced by 7%,22%,and 21%.
基金supported by the National Key Research and Development Program of China(Grant No.:2018YFC0807402)the National Natural Science Foundation of China(Grant No.:82073810)。
文摘In this study,we developed a novel on-line solid phase extraction(SPE)-ultra-high-performance liquid chromatography tandem mass spectrometry(UHPLC-MS/MS)-based analytical method for simultaneously quantifying 12 illicit drugs and metabolites(methamphetamine,amphetamine,morphine,codeine,6-monoacetylmorphine,benzoylecgonine,3,4-methylenedioxymethamphetamine,3,4-methylenedioxyamphetamine,cocaine,ketamine,norketamine,and methcathinone)and cotinine(COT)in wastewater samples.The analysis was performed by loading 2 m L of the sample onto an Oasis hydrophilic-lipophilic balance cartridge and using a cleanup step(5%methanol)to eliminate interference with a total run time of 13 min.The isotope-labeled internal standard method was used to quantify the target substances and correct for unavoidable losses and matrix effects during the on-line SPE process.Typical analytical characteristics used for method validation were sensitivity,linearity,precision,repeatability,recovery,and matrix effects.The limit of detection(LOD)and limit of quantification(LOQ)of each target were set at 0.20 ng/L and 0.50 ng/L,respectively.The linearity was between 0.5 ng/L and250 ng/L,except for that of COT.The intra-and inter-day precisions were<10.45%and 25.64%,respectively,and the relative recovery ranged from 83.74%to 162.26%.The method was used to analyze various wastewater samples from 33 cities in China,and the results were compared with the experimental results of identical samples analyzed using off-line SPE.The difference rate was between 19.91%and-20.44%,and the error range could be considered acceptable.These findings showed that on-line SPE is a suitable alternative to off-line SPE for the analysis of illicit drugs in samples.
基金the Forestry Science Technology and Development Project(KJZXSA2019046)Fundamental Research Funds for the Central Universities(2572017DA02).
文摘Korean pine(Pinus koraiensis Siebold&Zucc.)in Northeastern China has been genetically improved to increase seed yields in addition to timber.To assess seed yield variability and select highly productive clones,14 cone,seed and nut traits were measured and analyzed.Variance analysis showed that all clones were signifi cantly different in various traits(P<0.01).Phenotypic coeffi cients of variation and repeatability of traits ranged from 9.1 to 34.4%and from 27.5 to 97.7%,respectively.Except for the cone layer and cone seed numbers,the other traits were positively or negatively correlated.Three principal components were identifi ed.Seed and nut traits were the most important traits in the fi rst principal component,and cone traits more important in the second.Using correlation and principal component analyses,cone number and other traits were selected to evaluate materials.Twenty-two clones were selected using a selection rate of 10%based on cone number independently or other combined traits.The genetic gain for diff erent traits ranged from 6.2 to 24.3%.The selected elite clones can supply seedlings for reforestation and the selection method can provide a theoretical basis for selection in other conifer species.
基金Financial supports for this research were provided by the National Natural Science Foundation of China(Grants 11372060,11672057 and 11711530018)the 111 Project(Grant B14013)the Program of BK21 Plus.These supports are gratefully acknowledged.
文摘Fiber reinforced composite frame structure is an ideal lightweight and large-span structure in the fields of aerospace,satellite and wind turbine.Natural fundamental frequency is one of key indicators in the design requirement of the composite frame since structural resonance can be effectively avoided with the increase of the fundamental frequency.Inspired by the concept of integrated design optmization of composite frame structures and materials,the design optimization for the maximum structural fundamental frequency of fiber reinforced frame structures is proposed.An optimization model oriented at the maximum structural fundamental frequency under a composite material volume constraint is established.Two kinds of independent design variables are optimized,in which one is variables represented structural topology,the other is variables of continuous fiber winding angles.Sensitivity analysis of the frequency with respect to the two kinds of independent design variables is implemented with the semi-analytical sensitivity method.Some representative examples in the manuscript demonstrate that the integrated design optimization of composite structures can effectively explore coupled effects between structural configurations and material properties to increase the structural fundamental frequency.The proposed integrated optimization model has great potential to improve composite frames structural dynamic performance in aerospace industries.
基金MOE AcRF Tier2(2018-T2-2-005),MOE AcRF Tier1(2018-T1-005-001)A^(*)STAR AME IRG Grant SERC A1983c0027,Singapore.
文摘Semiconducting piezoelectricα-In_(2)Se_(3) and 3R MoS_(2) have attracted tremendous attention due to their unique electronic properties.Artificial van der Waals(vdWs)hetero-structures constructed withα-In_(2)Se_(3)and 3R MoS_(2)flakes have shown promising applications in optoelectronics and photocatal-ysis.Here,we present the first flexibleα-In_(2)Se_(3)/3R MoS_(2)vdWs p-n heterojunction devices for photodetection from the visible to near infrared region.These heterojunction devices exhibit an ultrahigh photoresponsivity of 2.9×10^(3)A W^(−1) and a substantial specific detectivity of 6.2×10^(10) Jones under a compressive strain of−0.26%.The photocurrent can be increased by 64%under a tensile strain of+0.35%,due to the heterojunction energy band modulation by piezoelectric polarization charges at the hetero-junction interface.This work demonstrates a feasible approach to enhancement of α-In_(2)Se_(3)/3R MoS_(2) photoelectric response through an appropriate mechanical stimulus.
基金supported by the National Natural Science Foundation of China(91537104,41375077,41775016,41405015,and 41405016)
文摘The simulation of soil temperature on the Tibetan Plateau(TP) plays a dominant role in the performance of both global climate and numerical weather forecast models. To improve the simulation of soil temperature on the TP, the Johansen soil thermal conductivity parameterization scheme was introduced into Community Land Model 3.5(CLM3.5) and Regional Climatic Model 4(Reg CM4). The improved CLM3.5 and Reg CM4-CLM were utilized to conduct offline and regional simulation experiments on the TP. Comparison of the new and old schemes revealed that CLM3.5 provides high thermal conductivity parameters of mineral soil solid on the TP. The Johansen scheme is more practical for the TP than the soil thermal conductivity parameterization in CLM3.5. The simulation of soil temperature and liquid water content was improved in offline experiment. The improved parameterization scheme can also reduce the simulation error of soil temperature in winter throughout the entire TP.
基金supported in part by the National Natural Science Foundation of China(61503132)。
文摘In order to improve the heat dissipation capability of motor controller for new energy vehicles,the water cooled radiator with multiple channels is optimized in this paper.The heat conduction between the heat source IGBT and the radiator,the convective heat transfer between the radiator and the coolant,the mechanical strength and the manufacturing cost are comprehensively considered during the optimization process.The power loss and thermal resistance of the IGBT unit are calculated at first,and finite element model of the radiator is established.On this basis,multi-physics coupling analysis of the water cooled radiator is carried out.Secondly,the sensitivity analysis is applied to verify the influence of structural parameters on the heat dissipation performance of the radiator system.The influence of coolant inlet velocity v,number of cooling ribs n,height of radiator ribs H on the maximum temperature rise T,the temperature difference ΔT between phase U and W,and the coolant pressure lossΔP are analyzed in depth,and the optimal range of the structural parameters for heat dissipation is obtained.Finally,an experimental platform was set up to verify the performance of the proposed structure of water cooled radiator for motor controller of new energy vehicle.The results show that the heat dissipation capability of the proposed radiator is improved compared with the initial design.
基金We are grateful to the Applied Technology Research and Development Planned Program of Heilongjiang Province(GA19B201-4)for supporting this research.
文摘Genetic parameters were evaluated for growth and cone characteristics(tree height,diameter at breast height,volume,cone number,thousand seeds weight and single cone seeds weight)on 86 half-sib families of Pinus koraiensis aged 31 years.Analyses of variance revealed significant differences(p<0.001)in all growth and cone traits among families while no significant differences were detected among blocks and the interaction between blocks and families.The average family values for growth traits were 17.22 m,8.67 cm and 0.43 m^(3) for tree height,diameter at breast height and volume,respectively.The average cone number,thousand seeds weight and single cone seeds weight were 17.57,748.91 g and 77.25 g,respectively.Genotypic additive variance and phenotypic variances ranged from 0.00009 to 3.820 and from 0.0005 to 23.066,while genotypic and phenotypic coefficients of variation ranged from 2.693%to 37.196%and 4.963%to 60.595%,respectively.Heritability at the individual and family level ranged from 0.152 to 0.215 and 0.611 to 0.862,respectively.Growth traits were significantly positively correlated with each other,but cone traits showed a weak correlation with growth traits.Based on 10% selection rate,nine families each were selected as elite materials in terms of high performance in volume and cone numbers,with 22.16%and 43.82%genetic gain in volume and cone number,respectively.These results provide beneficial information to select excellent families and establish orchards of P.koraiensis from improved seeds.
基金supported by the National Natural Science Foundation of China(31272515,31472165,31330076)
文摘Background: Human Cytomegalovirus(HCMV) infections can be found throughout the body, especially in epithelial tissue. Animal model was established by inoculation of HCMV(strain AD-169) or coinoculation with Hepatitis E virus(HEV) into the ligated sacculus rotundus and vermiform appendix in living rabbits. The specimens were collected from animals sacrificed 1 and a half hours after infection.Results: The virus was found to be capable of reproducing in these specimens through RT-PCR and Western-blot.Severe inflammation damage was found in HCMV-infected tissue. The viral protein could be detected in high amounts in the mucosal epithelium and lamina propria by immunohistochemistry and immunofluorescense.Moreover, there are strong positive signals in lymphocytes, macrophages, and lymphoid follicles. Quantitative statistics indicate that lymphocytes among epithlium cells increased significantly in viral infection groups.Conclusions: The results showed that HCMV or HEV + HCMV can efficiently infect in rabbits by vivo ligated intestine loop inoculation. The present study successfully developed an infective model in vivo rabbit ligated intestinal Loop for HCMV pathogenesis study. This rabbit model can be helpful for understanding modulation of the gut immune system with HCMV infection.
文摘Soil and climatic conditions are known to have close associations with plant morphological and stoichiometric traits at a regional scale along latitudinal gradients;however,how latitude drives biotic and abiotic factors affecting plant nutrient acquisition to accommodate environmental nutrient deficiency remains unclear.We quantified soil,root,leaf,and leaf litter nitrogen(N)and phosphorus(P)concentrations to determine the potentially limiting nutrient and the simultaneous responses of root capture and leaf resorption to nutrient deficiency in seven Quercus acutissima forests across the North–South Transect of Eastern China.The results showed that the mean leaf and root N:P ratios in Q.acutissima were 21.58 and 20.23,respectively,which markedly exceeded the P limitation threshold of 16 for terrestrial plants.The mean leaf litter N and P were 10.63 mg/g and 0.51 mg/g,respectively,indicating that P resorption proficiency was relatively higher than N resorption proficiency.N displayed higher stoichiometric homeostasis than P in the leaf.The leaf and root N:P ratios showed a quadratic variation that first decreased and then increased as latitude increased,whereas the phosphorus resorption efficiency and root-soil accumulation factor of P displayed the opposite trend.Partial least square path modeling(PLS-PM)analysis demonstrated that root nutrient capture and leaf nutrient resorption were regulated by different influential factors.Overall,these findings provide new insights into plant strategies to adapt to environmental nutrient deficiency,as well as the scientific basis for predicting the spatial and temporal patterns of nutrient acquisition in the context of climate change.
基金We received project support and design guidance from National Key R&D Program of China(Grant No.2021ZD0111201)The Na-tional Natural Science Foundation of China(Grant Nos.82161148011,72171013)+2 种基金Conselho Nacional de Desenvolvimento Científico e Tec-nolgico(CNPq-Refs.441057/2020-9,309569/2019-2),CJS-CNPqFundação deAmparo a Pesquisa do Estado do Rio de Janeiro(FAPERJ)The Russian Foundation for basic Research,Project number 21-51-80000.
文摘After the outbreak of COVID-19,the interaction of infectious disease systems and social systems has challenged traditional infectious disease modeling methods.Starting from the research purpose and data,researchers im-proved the structure and data of the compartment model or used agents and artificial intelligence based models to solve epidemiological problems.In terms of modeling methods,the researchers use compartment subdivi-sion,dynamic parameters,agent-based model methods,and artificial intelligence related methods.In terms of factors studied,the researchers studied 6 categories:human mobility,nonpharmaceutical interventions(NPIs),ages,medical resources,human response,and vaccine.The researchers completed the study of factors through modeling methods to quantitatively analyze the impact of social systems and put forward their suggestions for the future transmission status of infectious diseases and prevention and control strategies.This review started with a research structure of research purpose,factor,data,model,and conclusion.Focusing on the post-COVID-19 infectious disease prediction simulation research,this study summarized various improvement methods and analyzes matching improvements for various specific research purposes.
基金Supported by the National Key R&D Program of China(2021ZD0111201)National Natural Science Foundation of China(No.82161148011,72222022,72171013).
文摘Introduction:High-resolution data is essential for understanding the complexity of the relationship between the spread of coronavirus disease 2019(COVID-19),resident behavior,and interventions,which could be used to inform policy responses for future prevention and control.Methods:We obtained high-resolution human mobility data and epidemiological data at the community level.We propose a metapopulation Susceptible-Exposed-Presymptomatic-Infectious-Removal(SEPIR)compartment model to utilize the available data and explore the internal driving forces of COVID-19 transmission dynamics in the city of Wuhan.Additionally,we will assess the effectiveness of the interventions implemented in the smallest administrative units(subdistricts)during the lockdown.Results:In the Wuhan epidemic of March 2020,intra-subdistrict transmission caused 7.6 times more infections than inter-subdistrict transmission.After the city was closed,this ratio increased to 199 times.The main transmission path was dominated by population activity during peak evening hours.Discussion:Restricting the movement of people within cities is an essential measure for controlling the spread of COVID-19.However,it is difficult to contain intra-street transmission solely through citywide mobility restriction policies.This can only be accomplished by quarantining communities or buildings with confirmed cases,and conducting mass nucleic acid testing and enforcing strict isolation protocols for close contacts.
基金supported by the National Key Research and Development Program of the 13th Five-year Plan(Grant No.2017YFD070802-2)the China Special Fund for Agro-Scientific Research in the Public Interest(Grant No.201203059-01)+3 种基金the National Key Technology R&D Program(Grant No.2014BAD06B-1-05)the Open Fund Projects of Zhejiang Province Planting Equipment Technology Key Laboratory(Grant No.2013E10013-06)the National Natural Science Foundation of China(Grant No.51775104)by the National Key Technology R&D Program(Grant No.2014BAD06B01-13).
文摘The existing moving box mechanism pot seedling transplanting machine on the market moves too fast when the picked seedling is collected,which negatively impacts the seedling picking performance.In order to improve the performance,two types of variable speed continuous moving box schemes were designed in this study.The first scheme was to apply a spiral-gear moving box spiral shaft with sine curve characteristics in the box moving mechanism,whereas the second one was to change the circular gear in the moving box into an elliptical gear with a speed shifting transmission mechanism.The working mechanism of the mechanical structure was analyzed,and the kinematic model was established.A dynamic analysis of the slider mechanism was performed.A virtual prototype was established according to agronomic parameters,and the virtual prototype experiments were conducted in ADAMS.The physical prototype and the high-speed photography experiment were performed on the test bench of a transplanting machine frame.The theoretical analysis,virtual prototype and physical prototype test results were consistent,which verified the validity of the theoretical model,virtual prototype and physical prototype and ensured the feasibility of the system.
基金Acknowledgements This work was supported by the National Natural Science Foundation of China （Grant Nos. 61202426, 61272350）, the National Science Fund for Distinguished Young Scholars of China （61125102）, the State Key Program of National Natural Science of China （61133008）, the National High Technology Research and Development Program of China （2011AA010502）, the National key Technology R＆D Program （2012BAK26B02）.
基金supported in part by the National Natural Science Foundation of China(Grant No.61602022)State Key Laboratory of Sofware Development Environment(SKLSDE 2018ZX-07)+3 种基金CCF-Tencent IAGR20180101the Intermational Collaboration Project(B16001)Prof.Wang's work was parially supported by the National Key R&D Program of China(2019YFB2101804)the National Natural Sci-ence Foundation of China(Grant No.61572059).
文摘1 Introduction Deep learning has obtained a great success in computing technologies and has been afiliated to people's lives insepa-rably recent years.Nowadays,the most common approach to deploy these deep learning models is to collect the users data and train them in central servers.Nevertheless,the users data might be inevitably undermined during the process of col-lection and uploading,and users sensitive information might be exposed to danger.Aiming at reducing the risk of privacy leakage,Google proposed federated learning,which has been successfully applied to several applications,e.g.,data alliance among enterprises[1],next word prediction in Gboard[2],etc.
基金supported in part by National Institutes of Health grants DK083952,HD073070,DK099232,ES023438,,ES030429(to W.X.)WX is also supported in part by the Joseph Endowed Professorship from the University of Pittsburgh School of Pharmacy.
文摘Xenobiotic receptors are traditionally defined as xenobiotic chemical-sensing receptors,the activation of which transcriptionally regulates the expression of enzymes and transporters involved in the metabolism and disposition of xenobiotics.Emerging evidence suggests that“xenobiotic receptors”also have diverse endobiotic functions,including their effects on lipid metabolism and energy metabolism.Dyslipidemia is a major risk factor for cardiovascular disease,diabetes,obesity,metabolic syndrome,stroke,nonalcoholic fatty liver disease(NAFLD),and nonalcoholic steatohepatitis(NASH).Understanding the molecular mechanism by which transcriptional factors,including the xenobiotic receptors,regulate lipid homeostasis will help to develop preventive and therapeutic approaches.This review describes recent advances in our understanding the atypical roles of three xenobiotic receptors:aryl hydrocarbon receptor(AhR),pregnane X receptor(PXR),and constitutive androstane receptor(CAR),in metabolic disorders,with a particular focus on their effects on lipid and glucose metabolism.Collectively,the literatures suggest the potential values of AhR,PXR and CAR as therapeutic targets for the treatment of NAFLD,NASH,obesity and diabetes,and cardiovascular diseases.
基金supported by the National Natural Science Foundation of China(81972426 and 81874108)Special Projects for Strengthening Basic Research of Peking University(BMU2018JC005)National Key Technology R&D Program of China(2019YFC1005200 and 2019YFC1005201).
文摘Background BRCA1/2 mutations have been shown to be associated with the development of many solid tumors including endometrial cancer(EC).The objectives of this study are to analyze the association between BRCA1/2 mutational status and clinicopathological characteristics as well as outcomes in EC patients.Methods 510 eligible EC patients from the Cancer Genome Atlas database were included in the study.The association between clinicopathological characteristics and different BRCA1/2 mutational status was compared and analyzed.Analyses of the impact of BRCA mutations on survival in EC patients was conducted using Kaplan-Meier survival analyses and Cox regressions.In order to control confounding bias between groups,propensity score matching method was used.Results Among the eligible patients,11(2.2%)harbored BRCA1 mutation,43(8.4%)harbored BRCA2 mutation,and 36(7.1%)harbored both.Body mass index,rates of hypertension history,proportion of non-endometrioid histology and rates of positive peritoneal cytology were lower in patients with BRCA1/2 mutations compared with the group of wild-type counterpart(p=0.020,0.048,0.001 and 0.012,respectively).Patients with BRCA1/2 mutations showed longer overall(OS)and recurrence-free survival(RFS)(in Kaplan-Meier analyses,p<0.001 and p=0.004,respectively;in Cox regressions,p=0.001 and 0.007,respectively).Further analyses showed that the impact of BRCA mutations on survival was significant only in patients with high-grade endometrioid EC.Based on the cohorts generated after propensity score matching,in high-grade endometrioid EC patients,the influence of BRCA1/2 mutations remained significant on OS,but not on RFS(p=0.003 and 0.057 in Kaplan-Meier analyses,p=0.020 and 0.071 in Cox regressions).Conclusion BRCA1/2 mutations are associated with better survival in patients with high grade endometrioid EC,indicating the value of BRCA testing in EC clinical management.
