Plasma membrane intrinsic proteins(PIPs)are conserved plant aquaporins that transport small molecules across the plasma membrane to trigger instant stress responses and maintain cellular homeostasis under biotic and a...Plasma membrane intrinsic proteins(PIPs)are conserved plant aquaporins that transport small molecules across the plasma membrane to trigger instant stress responses and maintain cellular homeostasis under biotic and abiotic stress.To elucidate their roles in plant immunity to pathogen attack,we characterized the expression patterns,subcellular localizations,and H_(2)O_(2)-transport ability of 11 OsPIPs in rice(Oryza sativa),and identified OsPIP2;6 as necessary for rice disease resistance.OsPIP2;6 resides on the plasma membrane and facilitates cytoplasmic import of the immune signaling molecule H_(2)O_(2).Knockout of OsPIP2;6 increases rice susceptibility to Magnaporthe oryzae,indicating a positive function in plant immunity.OsPIP2;6 interacts with OsPIP2;2,which has been reported to increase rice resistance to pathogens via H_(2)O_(2)transport.Our findings suggest that OsPIP2;6 cooperates with OsPIP2;2 as a defense signal transporter complex during plant–pathogen interaction.展开更多
With the advancement of the construction of emerging engineering education,the reform of practical teaching has become an important task of higher engineering education.This article takes the course“Linux Operating S...With the advancement of the construction of emerging engineering education,the reform of practical teaching has become an important task of higher engineering education.This article takes the course“Linux Operating System Fundamentals”as an example to explore practical teaching reform in the context of emerging engineering education.By analyzing the current situation and problems in course practical teaching,we proposed practical teaching reforms such as online experiments,practical content updates,project-based engineering practices,and diversified evaluation models,and designed corresponding implementation plans.Practice has proved that this reform can improve students’learning interest and engineering practical skills,and cultivate outstanding engineers with innovative spirit and practical skills.展开更多
Apricots,scientifically known as Prunus armeniaca L,are drupes that resemble and are closely related to peaches or plums.As one of the top consumed fruits,apricots are widely grown worldwide except in Antarctica.A hig...Apricots,scientifically known as Prunus armeniaca L,are drupes that resemble and are closely related to peaches or plums.As one of the top consumed fruits,apricots are widely grown worldwide except in Antarctica.A high-quality reference genome for apricot is still unavailable,which has become a handicap that has dramatically limited the elucidation of the associations of phenotypes with the genetic background,evolutionary diversity,and population diversity in apricot.DNA from P.armeniaca was used to generate a standard,size-selected library with an average DNA fragment size of~20 kb.The library was run on Sequel SMRT Cells,generating a total of 16.54 Gb of PacBio subreads(N50=13.55 kb).The high-quality P.armeniaca reference genome presented here was assembled using long-read single-molecule sequencing at approximately 70×coverage and 171×Illumina reads(40.46 Gb),combined with a genetic map for chromosome scaffolding.The assembled genome size was 221.9 Mb,with a contig NG50 size of 1.02 Mb.Scaffolds covering 92.88%of the assembled genome were anchored on eight chromosomes.Benchmarking Universal Single-Copy Orthologs analysis showed 98.0%complete genes.We predicted 30,436 protein-coding genes,and 38.28%of the genome was predicted to be repetitive.We found 981 contracted gene families,1324 expanded gene families and 2300 apricot-specific genes.The differentially expressed gene(DEG)analysis indicated that a change in the expression of the 9-cis-epoxycarotenoid dioxygenase(NCED)gene but not lycopene beta-cyclase(LcyB)gene results in a lowβ-carotenoid content in the white cultivar“Dabaixing”.This complete and highly contiguous P.armeniaca reference genome will be of help for future studies of resistance to plum pox virus(PPV)and the identification and characterization of important agronomic genes and breeding strategies in apricot.展开更多
The accuracy of typhoon forecasts plays an important role in the prediction of storm surges.The uncertainty of a typhoon’s intensity and track means it is necessary to use an ensemble model to predict typhoon storm s...The accuracy of typhoon forecasts plays an important role in the prediction of storm surges.The uncertainty of a typhoon’s intensity and track means it is necessary to use an ensemble model to predict typhoon storm surges.A hydrodynamic model,which is operational at the National Marine Environmental Forecasting Center,is applied to conduct surge simulations for South China coastal areas using the best track data with parametric wind and pressure models.The results agree well with tidal gauge observations.To improve the calculation efficiency,the hydrodynamic model is modified using CUDA Fortran.The calculation results are almost the same as those from the original model,but the calculation time is reduced by more than 99%.A total of 150 typhoon cases are generated by combining 50 typhoon tracks from the European Centre for Medium-Range Weather Forecasts with three possible typhoon intensity forecasts.The surge ensembles are computed by the improved hydrodynamic model.Based on the simulated storm surges for the different typhoon cases,ensemble and probability forecast products can be provided.The mean ensemble results and probability forecast products are shown to agree well with the observed storm surge caused by Typhoon Mangkhut.The improved model is highly suitable for ensemble numerical forecasts,providing better forecast products for decision-making,and can be easily implemented to run on regular workstations.展开更多
To clarify the contribution of oxygen vacancies to room-temperature ferromagnetism(RTFM)in cobalt doped TiO_(2)(Co-TiO_(2)),and in order to obtain the high level of magnetization suitable for spintronic devices,in thi...To clarify the contribution of oxygen vacancies to room-temperature ferromagnetism(RTFM)in cobalt doped TiO_(2)(Co-TiO_(2)),and in order to obtain the high level of magnetization suitable for spintronic devices,in this work,Co-TiO_(2) nano-particles are prepared via the sol-gel route,followed by vacuum annealing for different durations,and the influence of vacu-um annealing duration on the structure and room-temperature magnetism of the compounds is examined.The results reveal that with an increase in annealing duration,the concentration of oxygen vacancies rises steadily,while the saturation magnetiza-tion(Ms)shows an initial gradual increase,followed by a sharp decline,and even disappearance.The maximum Ms is as high as 1.19 emu/g,which is promising with respect to the development of spintronic devices.Further analysis reveals that oxygen va-cancies,modulated by annealing duration,play a critical role in tuning room-temperature magnetism.An appropriate concentra-tion of oxygen vacancies is beneficial in terms of promoting RTFM in Co-TiO_(2).However,excessive oxygen vacancies will result in a negative impact on RTFM,due to antiferromagnetic superexchange interactions originating from nearest-neighbor Co^(2+)ions.展开更多
The measurement performance of the atom interferometry absolute gravimeter is strongly affected by the ground vibration noise.We propose a vibration noise evaluation scheme using a Michelson laser interferometer const...The measurement performance of the atom interferometry absolute gravimeter is strongly affected by the ground vibration noise.We propose a vibration noise evaluation scheme using a Michelson laser interferometer constructed by the intrinsic Raman laser of the atomic gravimeter.Theoretical analysis shows that the vibration phase measurement accuracy is better than 4 mrad,which corresponds to about 10-^10 g accuracy for a single shot gravity measurement.Compared with the commercial seismometer or accelerometer,this method is a simple,low cost,direct,and fully synchronized measurement of the vibration phase which should benefit the development of the atomic gravimeter.On the other side,limited by equivalence principle,the result of the laser interferometer is not absolute but relative vibration measurement.Triangular cap method could be used to evaluation the noise contribution of vibration,which is a different method from others and should benefit the development of the atomic gravimeter.展开更多
In this article, we focus on the Cauchy problem for the generalized IMBq system in n-dimensional space, which arises from DNA. We show the global existence and decay estimates of solution for a class of initial veloci...In this article, we focus on the Cauchy problem for the generalized IMBq system in n-dimensional space, which arises from DNA. We show the global existence and decay estimates of solution for a class of initial velocity, provided that the initial value is suitably small.展开更多
ATP-binding cassette(ABC)transporters are integral membrane proteins that have evolved diverse func-tions fulfilled via the transport of various substrates.In Arabidopsis,the G subfamily of ABC proteins is particularl...ATP-binding cassette(ABC)transporters are integral membrane proteins that have evolved diverse func-tions fulfilled via the transport of various substrates.In Arabidopsis,the G subfamily of ABC proteins is particularly abundant and participates in multiple signaling pathways during plant development and stress responses.In this study,we revealed that two Arabidopsis ABCG transporters,ABCG16 and ABCG25,engage in ABA-mediated stress responses and early plant growth through endomembrane-specific dimerization-coupled transport of ABA and ABA-glucosyl ester(ABA-GE),respectively.We first revealed that ABCG16 contributes to osmotic stress tolerance via ABA signaling.More specifically,ABCG16 induces cellular ABA efflux in both yeast and plant cells.Using FRET analysis,we showed that ABCG16 forms oblig-atory homodimers for ABA export activity and that the plasma membrane-resident ABCG16 homodimers specifically respond to ABA,undergoing notable conformational changes.Furthermore,we demonstrated that ABCG16 heterodimerizes with ABCG25 at the endoplasmic reticulum(ER)membrane and facilitates the ER entry of ABA-GE in both Arabidopsis and tobacco cells.The specific responsiveness of the ABCG16-ABCG25 heterodimer to ABA-GE and the superior growth of their double mutant support an inhib-itory role of these twoABCGs in early seedling establishment via regulation of ABA-GE translocation across the ER membrane.Our endomembrane-specific analysis of the FRET signals derived from the homo-or heterodimerized ABcG complexes allowed us to link endomembrane-biased dimerization to the transloca-tion of distinct substrates by ABcG transporters,providing a prototypic framework for understanding the omnipotence of ABcG transporters in plant development and stress responses.展开更多
Cellular hormone homeostasis is essential for precise spatial and temporal signaling responses and plantfitness.Abscisic acid(ABA)plays pivotal roles in orchestrating various developmental and stress re-sponses and co...Cellular hormone homeostasis is essential for precise spatial and temporal signaling responses and plantfitness.Abscisic acid(ABA)plays pivotal roles in orchestrating various developmental and stress re-sponses and confersfitness benefits over ecological and evolutionary timescales in terrestrial plants.Cellular ABA level is regulated by complex processes,including biosynthesis,catabolism,and transport.AtABCG25 is thefirst ABA exporter identified through genetic screening and affects diverse ABA responses.Resolving the structural basis of ABA export by ABCG25 is critical for further manipulations of ABA homeostasis and plantfitness.We used cryo-electron microscopy to elucidate the structural dynamics of AtABCG25 and successfully characterized different states,including apo AtABCG25,ABA-bound AtABCG25,and ATP-bound AtABCG25(E232Q).Notably,AtABCG25 forms a homodimer that fea-tures a deep,slit-like cavity in the transmembrane domain,and we precisely characterized the critical residues in the cavity where ABA binds.ATP binding triggers closure of the nucleotide-binding domains and conformational transitions in the transmembrane domains.We show that AtABCG25 belongs to a conserved ABCG subfamily that originated during the evolution of angiosperms.This subfamily neofunctionalized to regulate seed germination via the endosperm,in concert with the evolution of this angio-sperm-specific,embryo-nourishing tissue.Collectively,thesefindings provide valuable insights into the intricate substrate recognition and transport mechanisms of the ABA exporter AtABCG25,paving the way for genetic manipulation of ABA homeostasis and plantfitness.展开更多
渗透性和离子筛分能力是决定纳滤膜分离性能的主要指标.扩大渗透分离层的表面积不仅是提升膜通量的有效途径,还保持了盐的截留效果.受氨基/亚胺与酰氯缩合交联形成致密的聚酰胺网络的启发,我们提出了一种策略:将多孔的卟啉-苯胺共轭微...渗透性和离子筛分能力是决定纳滤膜分离性能的主要指标.扩大渗透分离层的表面积不仅是提升膜通量的有效途径,还保持了盐的截留效果.受氨基/亚胺与酰氯缩合交联形成致密的聚酰胺网络的启发,我们提出了一种策略:将多孔的卟啉-苯胺共轭微孔聚合物(PACMP)接枝到聚酰胺膜上,从而增大纳滤膜的分离表面积.通过一步界面聚合,制备了一种超渗透的共轭微孔聚合物-聚酰胺复合膜(CPCMs),其水通量为61.8 L m^(−2) h^(−1),对盐(Na_(2)SO_(4))的截留率高于91.6%.此外,由于PACMPs中卟啉基团产生的活性氧,原位光激发单线态氧1O2可杀死98.5%的大肠杆菌和99.7%的金黄色葡萄球菌,从而赋予了CMP-聚酰胺复合膜良好的抗菌性.展开更多
Microbial production of monoterpenoid indole alkaloids(MIAs)provides a sustainable and eco-friendly means to obtain compounds with high pharmaceutical values.However,efficient biosynthesis of MIAs in heterologous micr...Microbial production of monoterpenoid indole alkaloids(MIAs)provides a sustainable and eco-friendly means to obtain compounds with high pharmaceutical values.However,efficient biosynthesis of MIAs in heterologous microorganisms is hindered due to low supply of key precursors such as geraniol and its derivative 8-hydroxygeraniol catalyzed by geraniol 8-hydroxylase(G8H).In this study,we developed a facile evolution platform to screen strains with improved yield of geraniol by using the SCRaMbLE system embedded in the Sc2.0 synthetic yeast and confirmed the causal role of relevant genomic targets.Through genome mining,we identified several G8H enzymes that perform much better than the commonly used CrG8H for 8-hydroxygeraniol production in vivo.We further showed that the N-terminus of these G8H enzymes plays an important role in cellular activity by swapping experiments.Finally,the combination of the engineered chassis,optimized biosynthesis pathway,and utilization of G8H led to the final strain with more than 30-fold improvement in producing 8-hydroxygeraniol compared with the starting strain.Overall,this study will provide insights into the construction and optimization of yeast cells for efficient biosynthesis of 8-hydroxygeraniol and its derivatives.展开更多
We propose a fundamental theorem for eco-environmental surface modelling(FTEEM) in order to apply it into the fields of ecology and environmental science more easily after the fundamental theorem for Earth’s surface ...We propose a fundamental theorem for eco-environmental surface modelling(FTEEM) in order to apply it into the fields of ecology and environmental science more easily after the fundamental theorem for Earth’s surface system modeling(FTESM). The Beijing-Tianjin-Hebei(BTH) region is taken as a case area to conduct empirical studies of algorithms for spatial upscaling, spatial downscaling, spatial interpolation, data fusion and model-data assimilation, which are based on high accuracy surface modelling(HASM), corresponding with corollaries of FTEEM. The case studies demonstrate how eco-environmental surface modelling is substantially improved when both extrinsic and intrinsic information are used along with an appropriate method of HASM. Compared with classic algorithms, the HASM-based algorithm for spatial upscaling reduced the root-meansquare error of the BTH elevation surface by 9 m. The HASM-based algorithm for spatial downscaling reduced the relative error of future scenarios of annual mean temperature by 16%. The HASM-based algorithm for spatial interpolation reduced the relative error of change trend of annual mean precipitation by 0.2%. The HASM-based algorithm for data fusion reduced the relative error of change trend of annual mean temperature by 70%. The HASM-based algorithm for model-data assimilation reduced the relative error of carbon stocks by 40%. We propose five theoretical challenges and three application problems of HASM that need to be addressed to improve FTEEM.展开更多
a-Synuclein is a soluble monomer abundant in the central nervous system. Aggregates of a-synuclein,consisting of higher-level oligomers and insoluble fibrils,have been observed in many chronic neurological diseases an...a-Synuclein is a soluble monomer abundant in the central nervous system. Aggregates of a-synuclein,consisting of higher-level oligomers and insoluble fibrils,have been observed in many chronic neurological diseases and are implicated in neurotoxicity and neurodegeneration.a-Synuclein has recently been shown to aggregate following acute ischemic stroke, exacerbating neuronal damage.Propofol is an intravenous anesthetic that is commonly used during intravascular embolectomy following acute ischemic stroke. While propofol has demonstrated neuroprotective properties following brain injury, the mechanism of protection in the setting of ischemic stroke is unclear. In this study, propofol administration significantly reduced the neurotoxic aggregation of a-synuclein, decreased the infarct area, and attenuated the neurological deficits after ischemic stroke in a mouse model. We then demonstrated that the propofol-induced reduction of a-synuclein aggregation was associated with increased mammalian target of rapamycin/ribosomal protein S6 kinase beta-1 signaling pathway activity and reduction of the excessive autophagy occurring after acute ischemic stroke.展开更多
Ginsenoside Rg1(Rg1), the major effective component of ginseng, has been shown to have multiple bioactivities, but low oral bioavailability. The aim of this study was to develop a simple, sensitive and rapid high perf...Ginsenoside Rg1(Rg1), the major effective component of ginseng, has been shown to have multiple bioactivities, but low oral bioavailability. The aim of this study was to develop a simple, sensitive and rapid high performance liquid chromatography–tandem mass spectrometry(LC–MS/MS) method, which could be used to validate and quantify the concentrations of Rg1 and its metabolites in Sprague-Dawley rat bile,urine, and feces after oral administration(25 mg/kg). Calibration curves offered satisfactory linearity(r40.995)within the determined ranges. Both intra-day and inter-day variances were less than 15%, and the accuracy was within 80–120%. The excretion recoveries of Rg1, ginsenoside Rh1(Rh1), and protopanaxatriol(Ppt) in bile,urine, and feces combined were all greater than 70%. The fecal excretion recoveries of Rg1, Rh1, and Ppt were40.11%, 22.19%, and 22.88%, respectively, whereas 6.88% of Rg1 and 0.09% of Rh1 were excreted in bile.Urinary excretion accounted for only 0.04% of Rg1. In conclusion, the observed excretion profiles for Rg1 and its metabolites after oral administration are helpful for understanding the poor oral bioavailability of Rg1 and will aid further investigations of Rg1 as a pharmacologically active component.展开更多
We measured the concentrations of Cr,Fe,Ni,Cu,Zn,Cd,Pb and Hg,and the stable isotope ratios(δ^(13)C and δ^(15)N)in 87 fish samples within 12 economic fish species collected from the Dongting Lake,the second largest ...We measured the concentrations of Cr,Fe,Ni,Cu,Zn,Cd,Pb and Hg,and the stable isotope ratios(δ^(13)C and δ^(15)N)in 87 fish samples within 12 economic fish species collected from the Dongting Lake,the second largest freshwater lake in China.With few exceptions in concentration of Cr,most of fish species showed lower concentrations of the 8 metals than legislation thresholds.Piscivorous fishes had significantly higher values of δ^(15)N(possessing higher trophic level)and metal concentrations than planktivorous and herbivorous fishes.Moreover,demersal fishes showed higher concentrations of Cu,Zn,Cd and Pb than pelagic and benthopelagic fishes.We found positive correlations between concentrations of Fe,Pb and Hg and δ^(15)N ratio,confirming the biomagnification of the three metals through trophic transfer.In contrast,fishes showed clear growth dilution effect for Ni,Zn,Cu,Pb and Hg,indicated by the negative correlations between their concentrations and fish weight or length.Multiple regression analysis demonstrated that growth dilution and biomagnification effects simultaneously governed the metal concentrations in fish muscle,and the two effects'importance varied among different metals.The human health risk assessment indicated that all 8 metals gave target hazard quotient(THQ)values<1.0,i.e.,the estimated daily intake(EDI)of metals did not exceed the oral reference dose(Rf D),indicating a safe consumption of these fish species for consumer.Our study provides comprehensive approaches to better understand the determining processes and potential risk of heavy metals in freshwater lake fishes.展开更多
基金supported by the Guangdong Basic and Applied Basic Research Foundation(2020A1515111101,2022A1515110431).
文摘Plasma membrane intrinsic proteins(PIPs)are conserved plant aquaporins that transport small molecules across the plasma membrane to trigger instant stress responses and maintain cellular homeostasis under biotic and abiotic stress.To elucidate their roles in plant immunity to pathogen attack,we characterized the expression patterns,subcellular localizations,and H_(2)O_(2)-transport ability of 11 OsPIPs in rice(Oryza sativa),and identified OsPIP2;6 as necessary for rice disease resistance.OsPIP2;6 resides on the plasma membrane and facilitates cytoplasmic import of the immune signaling molecule H_(2)O_(2).Knockout of OsPIP2;6 increases rice susceptibility to Magnaporthe oryzae,indicating a positive function in plant immunity.OsPIP2;6 interacts with OsPIP2;2,which has been reported to increase rice resistance to pathogens via H_(2)O_(2)transport.Our findings suggest that OsPIP2;6 cooperates with OsPIP2;2 as a defense signal transporter complex during plant–pathogen interaction.
基金2023 China University of Geosciences(Beijing)Undergraduate Education Quality Improvement Plan Construction Project,including“Linux Operating System”Practical Teaching Reform(Project number:JG202215)“University Computer”Online Experiment Construction(Project number:JG202216)+1 种基金CUGB-Zhonggong Computer Science and Technology Off-Campus Practical Teaching Base(Project number:SSJJD202201)Ministry of Education Fund Project:Research and Development of Computer Vision Practical Courses Based on Deep Learning(Project number:2022BC003)。
文摘With the advancement of the construction of emerging engineering education,the reform of practical teaching has become an important task of higher engineering education.This article takes the course“Linux Operating System Fundamentals”as an example to explore practical teaching reform in the context of emerging engineering education.By analyzing the current situation and problems in course practical teaching,we proposed practical teaching reforms such as online experiments,practical content updates,project-based engineering practices,and diversified evaluation models,and designed corresponding implementation plans.Practice has proved that this reform can improve students’learning interest and engineering practical skills,and cultivate outstanding engineers with innovative spirit and practical skills.
基金supported by the research of the National Key R&D Program of China(2018YFD1000606-4)the Beijing Academy of Agriculture and Forestry Fund for Young Scholars(QNJJ201702,QNJJ201925)+1 种基金the National Natural Science Foundation of China(31401836)the Municipal Natural Science Foundation of Beijing(6162012).
文摘Apricots,scientifically known as Prunus armeniaca L,are drupes that resemble and are closely related to peaches or plums.As one of the top consumed fruits,apricots are widely grown worldwide except in Antarctica.A high-quality reference genome for apricot is still unavailable,which has become a handicap that has dramatically limited the elucidation of the associations of phenotypes with the genetic background,evolutionary diversity,and population diversity in apricot.DNA from P.armeniaca was used to generate a standard,size-selected library with an average DNA fragment size of~20 kb.The library was run on Sequel SMRT Cells,generating a total of 16.54 Gb of PacBio subreads(N50=13.55 kb).The high-quality P.armeniaca reference genome presented here was assembled using long-read single-molecule sequencing at approximately 70×coverage and 171×Illumina reads(40.46 Gb),combined with a genetic map for chromosome scaffolding.The assembled genome size was 221.9 Mb,with a contig NG50 size of 1.02 Mb.Scaffolds covering 92.88%of the assembled genome were anchored on eight chromosomes.Benchmarking Universal Single-Copy Orthologs analysis showed 98.0%complete genes.We predicted 30,436 protein-coding genes,and 38.28%of the genome was predicted to be repetitive.We found 981 contracted gene families,1324 expanded gene families and 2300 apricot-specific genes.The differentially expressed gene(DEG)analysis indicated that a change in the expression of the 9-cis-epoxycarotenoid dioxygenase(NCED)gene but not lycopene beta-cyclase(LcyB)gene results in a lowβ-carotenoid content in the white cultivar“Dabaixing”.This complete and highly contiguous P.armeniaca reference genome will be of help for future studies of resistance to plum pox virus(PPV)and the identification and characterization of important agronomic genes and breeding strategies in apricot.
基金The National Key Research and Development Program of China under contract Nos 2016YFC14015032018YFC140066 and 2018YFC1407001。
文摘The accuracy of typhoon forecasts plays an important role in the prediction of storm surges.The uncertainty of a typhoon’s intensity and track means it is necessary to use an ensemble model to predict typhoon storm surges.A hydrodynamic model,which is operational at the National Marine Environmental Forecasting Center,is applied to conduct surge simulations for South China coastal areas using the best track data with parametric wind and pressure models.The results agree well with tidal gauge observations.To improve the calculation efficiency,the hydrodynamic model is modified using CUDA Fortran.The calculation results are almost the same as those from the original model,but the calculation time is reduced by more than 99%.A total of 150 typhoon cases are generated by combining 50 typhoon tracks from the European Centre for Medium-Range Weather Forecasts with three possible typhoon intensity forecasts.The surge ensembles are computed by the improved hydrodynamic model.Based on the simulated storm surges for the different typhoon cases,ensemble and probability forecast products can be provided.The mean ensemble results and probability forecast products are shown to agree well with the observed storm surge caused by Typhoon Mangkhut.The improved model is highly suitable for ensemble numerical forecasts,providing better forecast products for decision-making,and can be easily implemented to run on regular workstations.
基金supported by the National Training Program of Innovation and Entrepreneurship for Undergraduates(No.201910389022).
文摘To clarify the contribution of oxygen vacancies to room-temperature ferromagnetism(RTFM)in cobalt doped TiO_(2)(Co-TiO_(2)),and in order to obtain the high level of magnetization suitable for spintronic devices,in this work,Co-TiO_(2) nano-particles are prepared via the sol-gel route,followed by vacuum annealing for different durations,and the influence of vacu-um annealing duration on the structure and room-temperature magnetism of the compounds is examined.The results reveal that with an increase in annealing duration,the concentration of oxygen vacancies rises steadily,while the saturation magnetiza-tion(Ms)shows an initial gradual increase,followed by a sharp decline,and even disappearance.The maximum Ms is as high as 1.19 emu/g,which is promising with respect to the development of spintronic devices.Further analysis reveals that oxygen va-cancies,modulated by annealing duration,play a critical role in tuning room-temperature magnetism.An appropriate concentra-tion of oxygen vacancies is beneficial in terms of promoting RTFM in Co-TiO_(2).However,excessive oxygen vacancies will result in a negative impact on RTFM,due to antiferromagnetic superexchange interactions originating from nearest-neighbor Co^(2+)ions.
基金Project supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB 21030200)the National Natural Science Foundation of China(Grant No.11904408).
文摘The measurement performance of the atom interferometry absolute gravimeter is strongly affected by the ground vibration noise.We propose a vibration noise evaluation scheme using a Michelson laser interferometer constructed by the intrinsic Raman laser of the atomic gravimeter.Theoretical analysis shows that the vibration phase measurement accuracy is better than 4 mrad,which corresponds to about 10-^10 g accuracy for a single shot gravity measurement.Compared with the commercial seismometer or accelerometer,this method is a simple,low cost,direct,and fully synchronized measurement of the vibration phase which should benefit the development of the atomic gravimeter.On the other side,limited by equivalence principle,the result of the laser interferometer is not absolute but relative vibration measurement.Triangular cap method could be used to evaluation the noise contribution of vibration,which is a different method from others and should benefit the development of the atomic gravimeter.
基金partially supported by NNSF of China(11871212)Plan For Scientific Innovation Talent of Henan Province(154100510012)
文摘In this article, we focus on the Cauchy problem for the generalized IMBq system in n-dimensional space, which arises from DNA. We show the global existence and decay estimates of solution for a class of initial velocity, provided that the initial value is suitably small.
基金supported by the National Natural Science Foundation of China(grant 32070292)the Shenzhen Science and Technology Program (grant KQTD20190929173906742)+2 种基金the Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes(grant 2019KSYS006)Shenzhen government for fundamental research(grant JCYJ20170817104523456)Scientific research funding for postdoctoral researchers staying at Shenzhen(grant K20227507).
文摘ATP-binding cassette(ABC)transporters are integral membrane proteins that have evolved diverse func-tions fulfilled via the transport of various substrates.In Arabidopsis,the G subfamily of ABC proteins is particularly abundant and participates in multiple signaling pathways during plant development and stress responses.In this study,we revealed that two Arabidopsis ABCG transporters,ABCG16 and ABCG25,engage in ABA-mediated stress responses and early plant growth through endomembrane-specific dimerization-coupled transport of ABA and ABA-glucosyl ester(ABA-GE),respectively.We first revealed that ABCG16 contributes to osmotic stress tolerance via ABA signaling.More specifically,ABCG16 induces cellular ABA efflux in both yeast and plant cells.Using FRET analysis,we showed that ABCG16 forms oblig-atory homodimers for ABA export activity and that the plasma membrane-resident ABCG16 homodimers specifically respond to ABA,undergoing notable conformational changes.Furthermore,we demonstrated that ABCG16 heterodimerizes with ABCG25 at the endoplasmic reticulum(ER)membrane and facilitates the ER entry of ABA-GE in both Arabidopsis and tobacco cells.The specific responsiveness of the ABCG16-ABCG25 heterodimer to ABA-GE and the superior growth of their double mutant support an inhib-itory role of these twoABCGs in early seedling establishment via regulation of ABA-GE translocation across the ER membrane.Our endomembrane-specific analysis of the FRET signals derived from the homo-or heterodimerized ABcG complexes allowed us to link endomembrane-biased dimerization to the transloca-tion of distinct substrates by ABcG transporters,providing a prototypic framework for understanding the omnipotence of ABcG transporters in plant development and stress responses.
基金supported by the National Natural Science Foundation of China (grant 32271251 to K.Y.,grant 32070292 to J.L.)the Guangdong Innovative and Entrepreneurial Research Team Program (grants 2021Z T09Y104 and 2021QN02Y429 to K.Y.)+2 种基金the Shenzhen Science and Technology Program (grants JCYJ20220530115214033 and KQTD20210811090115021 to K.Y.,grants JCYJ20170817104523456 and KQTD20190929173906742 to J.L.)Scientific research funding for postdoctoral researchers staying at Shenzhen (grant K20227507 to Y.Z.)supported by the Stable Support Plan Program of the Shenzhen Natural Science Fund (grant 20220815160107001).
文摘Cellular hormone homeostasis is essential for precise spatial and temporal signaling responses and plantfitness.Abscisic acid(ABA)plays pivotal roles in orchestrating various developmental and stress re-sponses and confersfitness benefits over ecological and evolutionary timescales in terrestrial plants.Cellular ABA level is regulated by complex processes,including biosynthesis,catabolism,and transport.AtABCG25 is thefirst ABA exporter identified through genetic screening and affects diverse ABA responses.Resolving the structural basis of ABA export by ABCG25 is critical for further manipulations of ABA homeostasis and plantfitness.We used cryo-electron microscopy to elucidate the structural dynamics of AtABCG25 and successfully characterized different states,including apo AtABCG25,ABA-bound AtABCG25,and ATP-bound AtABCG25(E232Q).Notably,AtABCG25 forms a homodimer that fea-tures a deep,slit-like cavity in the transmembrane domain,and we precisely characterized the critical residues in the cavity where ABA binds.ATP binding triggers closure of the nucleotide-binding domains and conformational transitions in the transmembrane domains.We show that AtABCG25 belongs to a conserved ABCG subfamily that originated during the evolution of angiosperms.This subfamily neofunctionalized to regulate seed germination via the endosperm,in concert with the evolution of this angio-sperm-specific,embryo-nourishing tissue.Collectively,thesefindings provide valuable insights into the intricate substrate recognition and transport mechanisms of the ABA exporter AtABCG25,paving the way for genetic manipulation of ABA homeostasis and plantfitness.
基金supported by the National Key Research and Development Program of China(2022YFB3807100,2022YFB3807102,and 2022YFB3807103)the National Natural Science Foundation of China(22102021 and 52073046)+4 种基金the Fundamental Research Funds for the Central Universities(2232022A-03)Shanghai Shuguang Program(19SG28)the Program of Shanghai Academic Research Leader(21XD1420200)Chang Jiang Scholar Program(Q2019152)the Natural Science Foundation of Shanghai(21ZR1402700 and 23ZR1401100).
文摘渗透性和离子筛分能力是决定纳滤膜分离性能的主要指标.扩大渗透分离层的表面积不仅是提升膜通量的有效途径,还保持了盐的截留效果.受氨基/亚胺与酰氯缩合交联形成致密的聚酰胺网络的启发,我们提出了一种策略:将多孔的卟啉-苯胺共轭微孔聚合物(PACMP)接枝到聚酰胺膜上,从而增大纳滤膜的分离表面积.通过一步界面聚合,制备了一种超渗透的共轭微孔聚合物-聚酰胺复合膜(CPCMs),其水通量为61.8 L m^(−2) h^(−1),对盐(Na_(2)SO_(4))的截留率高于91.6%.此外,由于PACMPs中卟啉基团产生的活性氧,原位光激发单线态氧1O2可杀死98.5%的大肠杆菌和99.7%的金黄色葡萄球菌,从而赋予了CMP-聚酰胺复合膜良好的抗菌性.
基金supported by grants from the National Key Research and Development Program of China (No.2021YFC2100800 to Y.Z.)the Science,Technology and Innovation Commission of Shenzhen Municipality under grant (No.JCYJ20180507183534578)the Tip-top Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program (2019TQ05Y876 to Y.S.)。
文摘Microbial production of monoterpenoid indole alkaloids(MIAs)provides a sustainable and eco-friendly means to obtain compounds with high pharmaceutical values.However,efficient biosynthesis of MIAs in heterologous microorganisms is hindered due to low supply of key precursors such as geraniol and its derivative 8-hydroxygeraniol catalyzed by geraniol 8-hydroxylase(G8H).In this study,we developed a facile evolution platform to screen strains with improved yield of geraniol by using the SCRaMbLE system embedded in the Sc2.0 synthetic yeast and confirmed the causal role of relevant genomic targets.Through genome mining,we identified several G8H enzymes that perform much better than the commonly used CrG8H for 8-hydroxygeraniol production in vivo.We further showed that the N-terminus of these G8H enzymes plays an important role in cellular activity by swapping experiments.Finally,the combination of the engineered chassis,optimized biosynthesis pathway,and utilization of G8H led to the final strain with more than 30-fold improvement in producing 8-hydroxygeraniol compared with the starting strain.Overall,this study will provide insights into the construction and optimization of yeast cells for efficient biosynthesis of 8-hydroxygeraniol and its derivatives.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41930647, 41590844, 41421001 & 41971358)the Strategic Priority Research Program (A) of the Chinese Academy of Sciences (Grant No. XDA20030203)+1 种基金the Innovation Project of LREIS (Grant No. O88RA600YA)the Biodiversity Investigation, Observation and Assessment Program (2019–2023) of the Ministry of Ecology and Environment of China。
文摘We propose a fundamental theorem for eco-environmental surface modelling(FTEEM) in order to apply it into the fields of ecology and environmental science more easily after the fundamental theorem for Earth’s surface system modeling(FTESM). The Beijing-Tianjin-Hebei(BTH) region is taken as a case area to conduct empirical studies of algorithms for spatial upscaling, spatial downscaling, spatial interpolation, data fusion and model-data assimilation, which are based on high accuracy surface modelling(HASM), corresponding with corollaries of FTEEM. The case studies demonstrate how eco-environmental surface modelling is substantially improved when both extrinsic and intrinsic information are used along with an appropriate method of HASM. Compared with classic algorithms, the HASM-based algorithm for spatial upscaling reduced the root-meansquare error of the BTH elevation surface by 9 m. The HASM-based algorithm for spatial downscaling reduced the relative error of future scenarios of annual mean temperature by 16%. The HASM-based algorithm for spatial interpolation reduced the relative error of change trend of annual mean precipitation by 0.2%. The HASM-based algorithm for data fusion reduced the relative error of change trend of annual mean temperature by 70%. The HASM-based algorithm for model-data assimilation reduced the relative error of carbon stocks by 40%. We propose five theoretical challenges and three application problems of HASM that need to be addressed to improve FTEEM.
基金the National Natural Science Foundation of China(81771139)the Beijing Natural Science Foundation(7194270).
文摘a-Synuclein is a soluble monomer abundant in the central nervous system. Aggregates of a-synuclein,consisting of higher-level oligomers and insoluble fibrils,have been observed in many chronic neurological diseases and are implicated in neurotoxicity and neurodegeneration.a-Synuclein has recently been shown to aggregate following acute ischemic stroke, exacerbating neuronal damage.Propofol is an intravenous anesthetic that is commonly used during intravascular embolectomy following acute ischemic stroke. While propofol has demonstrated neuroprotective properties following brain injury, the mechanism of protection in the setting of ischemic stroke is unclear. In this study, propofol administration significantly reduced the neurotoxic aggregation of a-synuclein, decreased the infarct area, and attenuated the neurological deficits after ischemic stroke in a mouse model. We then demonstrated that the propofol-induced reduction of a-synuclein aggregation was associated with increased mammalian target of rapamycin/ribosomal protein S6 kinase beta-1 signaling pathway activity and reduction of the excessive autophagy occurring after acute ischemic stroke.
基金supported by the National Natural Science Foundation of China(Nos.81173578 and 81573493)Beijing Key Laboratory of Non-Clinical Drug Metabolism and PK/PD study(No.Z141102004414062)+2 种基金National 863 Program of China(No.2014AA020803)the PUMC Youth Fund and Fundamental Research Funds for the Central Universities(No.3332015136)the Fundamental Research Funds for Central Public Institutes(No.2015CX12)
文摘Ginsenoside Rg1(Rg1), the major effective component of ginseng, has been shown to have multiple bioactivities, but low oral bioavailability. The aim of this study was to develop a simple, sensitive and rapid high performance liquid chromatography–tandem mass spectrometry(LC–MS/MS) method, which could be used to validate and quantify the concentrations of Rg1 and its metabolites in Sprague-Dawley rat bile,urine, and feces after oral administration(25 mg/kg). Calibration curves offered satisfactory linearity(r40.995)within the determined ranges. Both intra-day and inter-day variances were less than 15%, and the accuracy was within 80–120%. The excretion recoveries of Rg1, ginsenoside Rh1(Rh1), and protopanaxatriol(Ppt) in bile,urine, and feces combined were all greater than 70%. The fecal excretion recoveries of Rg1, Rh1, and Ppt were40.11%, 22.19%, and 22.88%, respectively, whereas 6.88% of Rg1 and 0.09% of Rh1 were excreted in bile.Urinary excretion accounted for only 0.04% of Rg1. In conclusion, the observed excretion profiles for Rg1 and its metabolites after oral administration are helpful for understanding the poor oral bioavailability of Rg1 and will aid further investigations of Rg1 as a pharmacologically active component.
基金supported by the National Natural Science Foundation of China(Nos.51709225,51622901,51939009)the Young Scientific Research Innovation Team Project of Xi’an University of Technology(No.104/256051715)。
文摘We measured the concentrations of Cr,Fe,Ni,Cu,Zn,Cd,Pb and Hg,and the stable isotope ratios(δ^(13)C and δ^(15)N)in 87 fish samples within 12 economic fish species collected from the Dongting Lake,the second largest freshwater lake in China.With few exceptions in concentration of Cr,most of fish species showed lower concentrations of the 8 metals than legislation thresholds.Piscivorous fishes had significantly higher values of δ^(15)N(possessing higher trophic level)and metal concentrations than planktivorous and herbivorous fishes.Moreover,demersal fishes showed higher concentrations of Cu,Zn,Cd and Pb than pelagic and benthopelagic fishes.We found positive correlations between concentrations of Fe,Pb and Hg and δ^(15)N ratio,confirming the biomagnification of the three metals through trophic transfer.In contrast,fishes showed clear growth dilution effect for Ni,Zn,Cu,Pb and Hg,indicated by the negative correlations between their concentrations and fish weight or length.Multiple regression analysis demonstrated that growth dilution and biomagnification effects simultaneously governed the metal concentrations in fish muscle,and the two effects'importance varied among different metals.The human health risk assessment indicated that all 8 metals gave target hazard quotient(THQ)values<1.0,i.e.,the estimated daily intake(EDI)of metals did not exceed the oral reference dose(Rf D),indicating a safe consumption of these fish species for consumer.Our study provides comprehensive approaches to better understand the determining processes and potential risk of heavy metals in freshwater lake fishes.
