Lake is an important part of the natural ecosystem, and its morphological characteristics reflect the capacity of lake regulation and storage, the strength of material migration, and the characteristics of shoreline d...Lake is an important part of the natural ecosystem, and its morphological characteristics reflect the capacity of lake regulation and storage, the strength of material migration, and the characteristics of shoreline development. In most existing studies, remote sensing images are used to quantify the morphological characteristics of lakes. However, the extraction accuracy of lake water is greatly affected by cloud cover and vegetation cover, and the inversion accuracy of lake elevation data is poor, which cannot accurately describe the response relationship of lake landscape morphology with water level change. Therefore, this paper takes Tonle Sap Lake as the research object, which is the largest natural freshwater lake in Southeast Asia. DEM is constructed based on high-resolution measured topographic data, and morphological indicators such as lake area, lake shoreline length, perimeter area ratio, longest axis length, maximum width, shoreline development index, lake shape complexity, compactness ratio and form ratio are adopted to researching the evolution law of high water overflows and low water outbursts quantitatively, and clarifying the variation characteristics of landscape morphology with water level gradient in Tonle Sap Lake. The research results have important theoretical significance for the scientific utilization of Tonle Sap Lake water resources and the protection of the lake ecosystem.展开更多
The flow of fluid through the porous matrix of a reservoir rock applies a seepage force to the solid rock matrix.Although the seepage force exerted by fluid flow through the porous matrix of a reservoir rock has a not...The flow of fluid through the porous matrix of a reservoir rock applies a seepage force to the solid rock matrix.Although the seepage force exerted by fluid flow through the porous matrix of a reservoir rock has a notable influence on rock deformation and failure,its effect on hydraulic fracture(HF)propagation remains ambiguous.Therefore,in this study,we improved a traditional fluid–solid coupling method by incorporating the role of seepage force during the fracturing fluid seepage,using the discrete element method.First,we validated the simulation results of the improved method by comparing them with an analytical solution of the seepage force and published experimental results.Next,we conducted numerical simulations in both homogeneous and heterogeneous sandstone formations to investigate the influence of seepage force on HF propagation.Our results indicate that fluid viscosity has a greater impact on the magnitude and extent of seepage force compared to injection rate,and that lower viscosity and injection rate correspond to shorter hydraulic fracture lengths.Furthermore,seepage force influences the direction of HF propagation,causing HFs to deflect towards the side of the reservoir with weaker cementation and higher permeability.展开更多
The effects of composite supports of CeO2-Al2O3, MgO-Al2O3, TiO2-Al2O3 or ZrO2-Al2O3 on the methanation activity of supported Co-Mo-based sulphur-resistant catalysts were investigated. The catalysts were further chara...The effects of composite supports of CeO2-Al2O3, MgO-Al2O3, TiO2-Al2O3 or ZrO2-Al2O3 on the methanation activity of supported Co-Mo-based sulphur-resistant catalysts were investigated. The catalysts were further characterized by nitrogen adsorption measurement, X-ray diffraction and X-ray photoelectron spectroscopy. The catalyst of 5%CoO-15%MoO3 supported on CeO2-Al2O3, MgO-Al2O3, TiO2-Al2O3 or ZrO2-Al2O3 composite oxides, respectively, showed different catalytic performances of syngas methanation in the presence of hydrogen sulphide as compared with that of the 5%CoO-15%MoO3/Al2O3 catalyst. The Co-Mo/CeO2-Al2O3 catalyst shows the highest methanation activity among the tested catalysts. The enhanced methanation activity may be attributed to the improvement of the dispersion of active metal species and the inhibition of the formation of S6+.展开更多
Hydroxycinnamoyl-CoA quinate transferase(HQT)is one of the key enzymes in the biosynthesis of chlorogenic acid(CGA)in the flowers of Lonicera japonica.However,the spatiotemporal expression patterns of HQT and its rela...Hydroxycinnamoyl-CoA quinate transferase(HQT)is one of the key enzymes in the biosynthesis of chlorogenic acid(CGA)in the flowers of Lonicera japonica.However,the spatiotemporal expression patterns of HQT and its relationship to the dynamics of CGA biosynthesis,transport,and storage remain largely unknown.In this study,we collected L.japonica flower samples at different growth stages(S1–S6)and examined the spatiotemporal expression pattern of HQT and the dynamic accumulation patterns of CGA using a combination of molecular and cytological techniques.Our results suggest that the spatiotemporal expression pattern of HQT is directly correlated with dynamic changes in CGA accumulation and distribution in L.japonica flowers.We further show that CGA is synthesized primarily in the cytoplasm and chloroplasts.CGA synthesized in the cytoplasm first accumulates in specialized vesicles and is then transferred to large central vacuoles for storage by fusion of CGA-containing vesicles with vacuoles.Furthermore,CGA synthesized in the chloroplasts appears to be transferred into the vacuoles for storage by direct membrane fusion between the tonoplast and the disrupted chloroplast membranes.Collectively,our results suggest that CGA is synthesized in chloroplasts and cytoplasm and finally transferred to the vacuole for long-term storage.展开更多
MV pulsed switch plays a key role as the transfer switch in large electromagnetic pulse simulators. To broaden the range of self-triggering time, a novel spark-discharge pre-ionization switch, in which the main gap el...MV pulsed switch plays a key role as the transfer switch in large electromagnetic pulse simulators. To broaden the range of self-triggering time, a novel spark-discharge pre-ionization switch, in which the main gap electric field is superposed at the trigger gap to let the electrons in its spark channel also become initial electrons, is proposed and tested. The design idea is: as electrons in the spark channel of the trigger gap always exist after its breakdown, the injection time of pre-ionization should have a more negligible effect on reducing the switch jitter. The experiment results under pulses with a rise time of ~100 ns support the above assumptions.When the operating voltage is from ~300 to ~800 kV and the self-triggering time is ~45% to~75% of the peak time, the breakdown time delay jitter is less than 2 ns, and the breakdown voltage jitter is smaller than 1.25%. Under specific self-triggering time, the breakdown time delay jitter is less than 1.5 ns, and the breakdown voltage jitter is smaller than 0.8%.展开更多
Located at the northeastern margin of the Tibetan plateau,the Ordos block is a stable tectonic unit in North China.With its active boundary fault zones,the Ordos block played an important role in the eastward extrusio...Located at the northeastern margin of the Tibetan plateau,the Ordos block is a stable tectonic unit in North China.With its active boundary fault zones,the Ordos block played an important role in the eastward extrusion mechanism of the Tibetan plateau.Peking University deployed a linear array of 15 portable broadband seismometers across the western Weihe graben during September 2005 to August 2006 and later a 2-D seismic array(Southwest Ordos Array) of 14 portable broadband seismometers during 2007-2008 at its southwestern boundary.Analyses of shear wave splitting of SKS and SKKS phases at these stations show that the fast directions trend ~110° with an average delay time of 0.9 s in the southwestern margin of the Ordos block.The agreement between the lithosphere deformation indicated by GPS data and Quaternary fault slip-rate observations and the mantle flow represented by shear wave splitting implies that accordant deformation patterns from lithosphere to asthenosphere in relation to the eastward extrusion of the Tibetan plateau could extend at least to 200 km depth.Spatial distribution of splitting polarization directions indicates that the mantle flow driven by the Tibetan plateau is blocked by the Ordos block and locally restricted in a narrow channel along the Qinling-Dabie fault zones between the Ordos block and Sichuan basin.展开更多
In this paper, a calculation model for the breakdown time delay and jitter of gas switches under hundred-nanosecond pulses is proposed and applied in a self-triggered pre-ionized switch. The effects of injection time ...In this paper, a calculation model for the breakdown time delay and jitter of gas switches under hundred-nanosecond pulses is proposed and applied in a self-triggered pre-ionized switch. The effects of injection time of pre-ionization, pulse rise time, and the pre-ionization jitter are discussed and verified through experiments. It indicates that the pre-ionization should be injected when the electric field is high enough in the gap, injection after 80% peak-time can ensure its effectiveness.Then the statistical time delay jitter will be determined by the pre-ionization jitter, which is an intrinsic restriction of the self-triggered switch. However, when the changing rate of the pulsed electric field exceeds a certain value, the breakdown time delay jitter can be partly offset in the formative stage because the formative time delay has an exponential relationship with the electric field. Therefore, lower time jitter can be obtained under pulses with a shorter pulse rise time. In general, the results of the calculation model agree with the experimental results, and the experimental parameters which lead to a low jitter can also be used as a reference.展开更多
Carbonate reservoirs in Western China show tremendous exploration and development potential.These have become the key area for oil and gas reserves addition and sustainable resource development for China.Compared to c...Carbonate reservoirs in Western China show tremendous exploration and development potential.These have become the key area for oil and gas reserves addition and sustainable resource development for China.Compared to conventional carbonate reservoirs,prediction of this kind of reservoir predominated by secondary storage is much more difficultand presents significant challenges.展开更多
This work investigates the pulsed breakdown processes and mechanisms of self-triggered preionized switches with a four-electrode structure in nitrogen through intensified charge coupled device photographs.The diameter...This work investigates the pulsed breakdown processes and mechanisms of self-triggered preionized switches with a four-electrode structure in nitrogen through intensified charge coupled device photographs.The diameter of the trigger plane hole mainly determines the switch’s electric field distribution.Two configurations with minimum and maximum trigger plane holes are adopted for comparison.In the switch with a minimum trigger plane hole,the maximum electric field distributes at the surfaces of the main electrodes.Although charged particles in the triggering spark channel cannot drift out,homogeneous discharges can be stimulated from both the cathode and anode surfaces through ultraviolet illumination.Two sub-gaps are likely to break down simultaneously.In the switch with a maximum trigger plane hole,the maximum electric field locates near the trigger electrodes.Discharges in both sub-gaps initiate from the trigger electrodes in the form of a positive or negative streamer.Due to the lower breakdown voltage and electric field threshold for discharge initiation,the cathode side sub-gap breaks down first.The analysis of two extreme examples can be referenced in the future design and improvement of self-triggered four-electrode switches with different trigger electrode structures.展开更多
Maize is a major staple crop widely used as food,animal feed,and raw materials in industrial production.High-density planting is a major factor contributing to the continuous increase of maize yield.However,high plant...Maize is a major staple crop widely used as food,animal feed,and raw materials in industrial production.High-density planting is a major factor contributing to the continuous increase of maize yield.However,high planting density usually triggers a shade avoidance response and causes increased plant height and ear height,resulting in lodging and yield loss.Reduced plant height and ear height,more erect leaf angle,reduced tassel branch number,earlier flowering,and strong root system architecture are five key morphological traits required for maize adaption to high-density planting.In this review,we summarize recent advances in deciphering the genetic and molecular mechanisms of maize involved in response to high-density planting.We also discuss some strategies for breeding advanced maize cultivars with superior performance under high-density planting conditions.展开更多
Photodynamic therapy(PDT)has emerged as a promising approach for squamous cell carcinoma treatment but hindered by tumor hypoxia,acquired resistance,phototoxicity,and so on.To address these issues,we developed a smart...Photodynamic therapy(PDT)has emerged as a promising approach for squamous cell carcinoma treatment but hindered by tumor hypoxia,acquired resistance,phototoxicity,and so on.To address these issues,we developed a smart strategy utilizing activable photosensitizers delivered by an aptamer-functionalized DNA probe(ADP).The ADP incorporated an AS1411 aptamer for tumor targeting and a linear antisense oligonucleotide(ASO)for recognition of Survivin mRNA.In the absence of the target,PDT remained quenched,thereby avoiding phototoxicity during circulation and nonselective distribution.With the aid of the aptamer,ADP achieved selective targeting of tumors.Upon internalization,ADP targeted recognized Survivin mRNA,triggering PDT activation,and releasing ASO to down-regulate Survivin expression and reverse tumor resistance.Consequently,the activable photosensitizers exhibited an“AND”logic gate,combining tumor-targeting delivery and tumor-related gene activation,thus enhancing its specificity.Additionally,the incorporation of hemin into the ADP provided catalase activity,converting tumor-abundant H_(2)O_(2) into O_(2),thereby ameliorating tumor hypoxia.The resulting functionalized G-quadruplex/hemin–DNA probe complex demonstrated targeted delivery and activation,minimized side effects,and enhanced PDT efficacy in both xenograft tumor-bearing mice and patient-derived xenograft models.This study offers a unique and promising platform for efficient and safe PDT,thus holding great potential for future clinical translation and improved cancer therapy.展开更多
N6-Methyladenosine(m^(6)A)is one of the most abundant modifications of eukaryotic mRNA,but its comprehensive biological functionality remains further exploration.In this study,we identified and characterized a new flo...N6-Methyladenosine(m^(6)A)is one of the most abundant modifications of eukaryotic mRNA,but its comprehensive biological functionality remains further exploration.In this study,we identified and characterized a new flowering-promoting gene,EARLY HEADING DATE6(EHD6),in rice.EHD6 encodes an RNA recognition motif(RRM)-containing RNA binding protein that is localized in the non-membranous cytoplasm ribonucleoprotein(RNP)granules and can bind both m^(6)A-modified RNA and unmodified RNA indiscriminately.We found that EHD6 can physically interact with YTH07,a YTH(YT521-B homology)domain-containing m^(6)A reader.We showed that their interaction enhances the binding of an m^(6)A-modified RNA and triggers relocation of a portion of YTH07 from the cytoplasm into RNP granules through phase-separated condensation.Within these condensates,the mRNA of a rice flowering repressor,CONSTANS-like 4(OsCOL4),becomes sequestered,leading to a reduction in its protein abundance and thus accelerated flowering through the Early heading date 1 pathway.Taken together,these results not only shed new light on the molecular mechanism of efficient m^(6)A recognition by the collaboration between an RNA binding protein and YTH family m^(6)A reader,but also uncover the potential for m^(6)A-mediated translation regulation through phaseseparated ribonucleoprotein condensation in rice.展开更多
The carbon cycle plays a pivotal role in regulating Earth’s surface environment through atmospheric-oceanic acid-base and redox processes, functioning as the engine driving the evolution of our planet’s surface. A d...The carbon cycle plays a pivotal role in regulating Earth’s surface environment through atmospheric-oceanic acid-base and redox processes, functioning as the engine driving the evolution of our planet’s surface. A deep understanding of the carbon cycle’s evolution is thus essential for our understanding of the evolution of our planet’s habitability.展开更多
Over the past few decades,significant improvements in maize yield have been largely attributed to increased plant density of upright hybrid varieties rather than increased yield per plant.However,dense planting trigge...Over the past few decades,significant improvements in maize yield have been largely attributed to increased plant density of upright hybrid varieties rather than increased yield per plant.However,dense planting triggers shade avoidance responses(SARs)that optimize light absorption but impair plant vigor and performance,limiting yield improvement through increasing plant density.In this study,we demonstrated that high-density-induced leaf angle narrowing and stem/stalk elongation are largely dependent on phytochrome B(phyB1/B2),the primaryphotoreceptor responsible for perceiving red(R)and far-red(FR)light in maize.We found that maize phyB physically interacts with the LIGULELESS1(LG1),a classical key regulator of leaf angle,to coordinately regulate plant architecture and density tolerance.The abundance of LG1 is significantly increased by phyB under high R:FR light(low density)but rapidly decreases under low R:FR light(high density),correlating with variations in leaf angle and plant height under various densities.In addition,we identified the homeobox transcription factor HB53 as a target co-repressed by both phyB and LG1 but rapidly induced by canopy shade.Genetic and cellular analyses showed that HB53 regulates plant architecture by controlling the elongation and division of ligular adaxial and abaxial cells.Taken together,these findings uncover the phyB-LG1-HB53 regulatory module as a key molecular mechanism governing plant architecture and density tolerance,providing potential genetic targets for breeding maize hybrid varieties suitable for high-density planting.展开更多
Waste heat recovery of high-temperature granules is one of the most promising sustainable energy supply and carbon reduction ways for industry.A moving bed indirect heat exchanger(MBIHE)with inner-migration was propos...Waste heat recovery of high-temperature granules is one of the most promising sustainable energy supply and carbon reduction ways for industry.A moving bed indirect heat exchanger(MBIHE)with inner-migration was proposed for granular heat recovery.Granule migration and the enhanced heat transfer induced by two types of agitators(i.e.,agitator with slanted stick A_(s)and with plow-shaped surface A_(p))in the MBIHE are analyzed based on DEM coupled with CFD.Owing to the effective agitation,the average heat transfer coefficient in the granule side is enhanced to∼3 times compared to that without agitation.The heat recovery efficiency in the moving bed reached more than 70%with the agitations of either A_(s)or A_(p).The heat efficiency of A_(s)is∼7%higher than that of A_(p),but with at least 60%greater rotational torque.To ensure reliable agitation,the A_(p)is suggested to be adopted in the MBIHE to induce granule migration.展开更多
Correction:aBI0TECH(2021)2:131-145 https://doi.0rg/10.1007/s42994-021-00038-1 In this article the author's name Fereshteh Jafari was incorrectly written as Feresheeh Jafari.The original article has been corrected....Correction:aBI0TECH(2021)2:131-145 https://doi.0rg/10.1007/s42994-021-00038-1 In this article the author's name Fereshteh Jafari was incorrectly written as Feresheeh Jafari.The original article has been corrected.Open Access This article is licensed under a Creative Commons Attribution 4.0 International License,which permits use,sharing,adaptation,distribution and reproduction in any medium or format.展开更多
Hard-to-dissolve polymers provide next-generation alternatives for high-performance filter materials owing to their intrin-sically high chemical stability,superior mechanical performance,and excellent high-temperature...Hard-to-dissolve polymers provide next-generation alternatives for high-performance filter materials owing to their intrin-sically high chemical stability,superior mechanical performance,and excellent high-temperature resistance.However,the mass production of hard-to-dissolve nanofibers still remains a critical challenge.A simple,scalable,and low-cost ionic solu-tion blow-spinning method has herein been provided for the large-scale preparation of hard-to-dissolve Nomex polymeric nanofibers with an average diameter of nearly 100 nm.After rapidly dissolving Nomex microfibers in the lithium chloride/dimethylacetamide(LiCl/DMAc)solution system,the conductive solution can be stably and conductivity-independently processed into nanofibers.The method optimizes electrospinning and avoids spinnability degradation and potential safety hazards caused by high electrical conductivity.Owing to nanofibrous structure and high dipole moment,Nomex nanofibrous filters show a stable high filtration efficiency of 99.92%for PM_(0.3) with a low areal density of 4.6 g m^(-2),as well as a low-pressure drop of 189.47 Pa.Moreover,the flame-retardant filter can work at 250°C and 280°C for a long and short time without shrinking or burning,respectively,exhibiting a high filtration efficiency of 99.50%for PM_(0.3-10.0).The outstanding properties and low cost enable the efficient capture of PM from various high-temperature exhausts,making Nomex nanofi-brous membrane an even more ideal industrial-grade air filter than polypropylene,polytetrafluoroethylene,polyimide,and ceramic nanofibrous filters.展开更多
Plastid-to-nucleus retrograde signaling coordinates nuclear gene expression with chloroplast developmental status and is essential for the photoautotrophic lifestyle of plants.Previous studies have established that te...Plastid-to-nucleus retrograde signaling coordinates nuclear gene expression with chloroplast developmental status and is essential for the photoautotrophic lifestyle of plants.Previous studies have established that tetrapyrrole biosynthesis(TPB)and plastid gene expression(PGE)play essential roles in plastid retrograde signaling during early chloroplast biogenesis;however,their functional relationship remains unknown.In this study,we generated a series of rice TPB-related gun(genome uncoupled)mutants and systematically analyzed their effects on nuclear and plastid gene expression under normal conditions or when subjected to treatments with norflurazon(NF;a noncompetitive inhibitor of carotenoid biosynthesis)and/or lincomycin(Lin;a specific inhibitor of plastid translation).We show that under NF treatment,expression of plastid-encoded polymerase(PEP)-transcribed genes is significantly reduced in the wild type but is derepressed in the TPB-related gun mutants.We further demonstrate that the derepressed expression of PEPtranscribed genes may be caused by increased expression of the PEP core subunit and nuclear-encoded sigma factors and by elevated copy numbers of plastid genome per haploid genome.In addition,we show that expression of photosynthesis-associated nuclear genes(PhANGs)and PEP-transcribed genes is correlated in the rice TPB-related gun mutants,with or without NF or Lin treatment.A similar correlation between PhANGs and PGE is also observed in the Arabidopsis gun4 and gun5 mutants.Moreover,we show that increased expression of PEP-transcribed plastid genes is necessary for the gun phenotype in NF-treated TPB-related gun mutants.Further,we provide evidence that these TPB-related GUN genes act upstream of GUN1 in the regulation of retrograde signaling.Taken together,our results suggest that the TPB-related GUN genes control retrograde plastid signaling by regulating the PGE-dependent retrograde signaling pathway.展开更多
In the last decade,it has become increasingly recognized that a balanced gut microbiota plays an important role in maintaining the health of the host.Numerous clinical and preclinical studies have shown that changes i...In the last decade,it has become increasingly recognized that a balanced gut microbiota plays an important role in maintaining the health of the host.Numerous clinical and preclinical studies have shown that changes in gut microbiota composition are associated with a variety of neurological diseases,e.g.,Parkinson’s disease,Alzheimer’s disease,and myasthenia gravis.However,the underlying molecular mechanisms are complex and remain unclear.Behavioral phenotypes can be transmitted from humans to animals through gut microbiota transplantation,indicating that the gut microbiota may be an important regulator of neurological diseases.However,further research is required to determine whether animal-based findings can be extended to humans and to elucidate the relevant potential mechanisms by which the gut microbiota regulates neurological diseases.Such investigations may aid in the development of new microbiota-based strategies for diagnosis and treatment and improve the clinical management of neurological disorders.In this review,we describe the dysbiosis of gut microbiota and the corresponding mechanisms in common neurological diseases,and discuss the potential roles that the intestinal microbiome may play in the diagnosis and treatment of neurological disorders.展开更多
文摘Lake is an important part of the natural ecosystem, and its morphological characteristics reflect the capacity of lake regulation and storage, the strength of material migration, and the characteristics of shoreline development. In most existing studies, remote sensing images are used to quantify the morphological characteristics of lakes. However, the extraction accuracy of lake water is greatly affected by cloud cover and vegetation cover, and the inversion accuracy of lake elevation data is poor, which cannot accurately describe the response relationship of lake landscape morphology with water level change. Therefore, this paper takes Tonle Sap Lake as the research object, which is the largest natural freshwater lake in Southeast Asia. DEM is constructed based on high-resolution measured topographic data, and morphological indicators such as lake area, lake shoreline length, perimeter area ratio, longest axis length, maximum width, shoreline development index, lake shape complexity, compactness ratio and form ratio are adopted to researching the evolution law of high water overflows and low water outbursts quantitatively, and clarifying the variation characteristics of landscape morphology with water level gradient in Tonle Sap Lake. The research results have important theoretical significance for the scientific utilization of Tonle Sap Lake water resources and the protection of the lake ecosystem.
基金National Natural Science Foundation of China(51934005,U23B2089)Shaanxi Provincial Natural Science Basic Research Program Project(2024JC-YBQN-0554).
文摘The flow of fluid through the porous matrix of a reservoir rock applies a seepage force to the solid rock matrix.Although the seepage force exerted by fluid flow through the porous matrix of a reservoir rock has a notable influence on rock deformation and failure,its effect on hydraulic fracture(HF)propagation remains ambiguous.Therefore,in this study,we improved a traditional fluid–solid coupling method by incorporating the role of seepage force during the fracturing fluid seepage,using the discrete element method.First,we validated the simulation results of the improved method by comparing them with an analytical solution of the seepage force and published experimental results.Next,we conducted numerical simulations in both homogeneous and heterogeneous sandstone formations to investigate the influence of seepage force on HF propagation.Our results indicate that fluid viscosity has a greater impact on the magnitude and extent of seepage force compared to injection rate,and that lower viscosity and injection rate correspond to shorter hydraulic fracture lengths.Furthermore,seepage force influences the direction of HF propagation,causing HFs to deflect towards the side of the reservoir with weaker cementation and higher permeability.
文摘The effects of composite supports of CeO2-Al2O3, MgO-Al2O3, TiO2-Al2O3 or ZrO2-Al2O3 on the methanation activity of supported Co-Mo-based sulphur-resistant catalysts were investigated. The catalysts were further characterized by nitrogen adsorption measurement, X-ray diffraction and X-ray photoelectron spectroscopy. The catalyst of 5%CoO-15%MoO3 supported on CeO2-Al2O3, MgO-Al2O3, TiO2-Al2O3 or ZrO2-Al2O3 composite oxides, respectively, showed different catalytic performances of syngas methanation in the presence of hydrogen sulphide as compared with that of the 5%CoO-15%MoO3/Al2O3 catalyst. The Co-Mo/CeO2-Al2O3 catalyst shows the highest methanation activity among the tested catalysts. The enhanced methanation activity may be attributed to the improvement of the dispersion of active metal species and the inhibition of the formation of S6+.
基金supported by the National Natural Science Foundation of China(31500261)the Guangdong Province Science and Technology Plan Project(2014B090904074)+1 种基金the Youth Foundation of the College of Forestry and Landscape Architecture of South China Agricultural University(201603)open funds from the State Key Laboratory for the Conservation and Utilization of Subtropical Agro-Bioresources(SKLCUSA-b201701).
文摘Hydroxycinnamoyl-CoA quinate transferase(HQT)is one of the key enzymes in the biosynthesis of chlorogenic acid(CGA)in the flowers of Lonicera japonica.However,the spatiotemporal expression patterns of HQT and its relationship to the dynamics of CGA biosynthesis,transport,and storage remain largely unknown.In this study,we collected L.japonica flower samples at different growth stages(S1–S6)and examined the spatiotemporal expression pattern of HQT and the dynamic accumulation patterns of CGA using a combination of molecular and cytological techniques.Our results suggest that the spatiotemporal expression pattern of HQT is directly correlated with dynamic changes in CGA accumulation and distribution in L.japonica flowers.We further show that CGA is synthesized primarily in the cytoplasm and chloroplasts.CGA synthesized in the cytoplasm first accumulates in specialized vesicles and is then transferred to large central vacuoles for storage by fusion of CGA-containing vesicles with vacuoles.Furthermore,CGA synthesized in the chloroplasts appears to be transferred into the vacuoles for storage by direct membrane fusion between the tonoplast and the disrupted chloroplast membranes.Collectively,our results suggest that CGA is synthesized in chloroplasts and cytoplasm and finally transferred to the vacuole for long-term storage.
文摘MV pulsed switch plays a key role as the transfer switch in large electromagnetic pulse simulators. To broaden the range of self-triggering time, a novel spark-discharge pre-ionization switch, in which the main gap electric field is superposed at the trigger gap to let the electrons in its spark channel also become initial electrons, is proposed and tested. The design idea is: as electrons in the spark channel of the trigger gap always exist after its breakdown, the injection time of pre-ionization should have a more negligible effect on reducing the switch jitter. The experiment results under pulses with a rise time of ~100 ns support the above assumptions.When the operating voltage is from ~300 to ~800 kV and the self-triggering time is ~45% to~75% of the peak time, the breakdown time delay jitter is less than 2 ns, and the breakdown voltage jitter is smaller than 1.25%. Under specific self-triggering time, the breakdown time delay jitter is less than 1.5 ns, and the breakdown voltage jitter is smaller than 0.8%.
文摘Located at the northeastern margin of the Tibetan plateau,the Ordos block is a stable tectonic unit in North China.With its active boundary fault zones,the Ordos block played an important role in the eastward extrusion mechanism of the Tibetan plateau.Peking University deployed a linear array of 15 portable broadband seismometers across the western Weihe graben during September 2005 to August 2006 and later a 2-D seismic array(Southwest Ordos Array) of 14 portable broadband seismometers during 2007-2008 at its southwestern boundary.Analyses of shear wave splitting of SKS and SKKS phases at these stations show that the fast directions trend ~110° with an average delay time of 0.9 s in the southwestern margin of the Ordos block.The agreement between the lithosphere deformation indicated by GPS data and Quaternary fault slip-rate observations and the mantle flow represented by shear wave splitting implies that accordant deformation patterns from lithosphere to asthenosphere in relation to the eastward extrusion of the Tibetan plateau could extend at least to 200 km depth.Spatial distribution of splitting polarization directions indicates that the mantle flow driven by the Tibetan plateau is blocked by the Ordos block and locally restricted in a narrow channel along the Qinling-Dabie fault zones between the Ordos block and Sichuan basin.
文摘In this paper, a calculation model for the breakdown time delay and jitter of gas switches under hundred-nanosecond pulses is proposed and applied in a self-triggered pre-ionized switch. The effects of injection time of pre-ionization, pulse rise time, and the pre-ionization jitter are discussed and verified through experiments. It indicates that the pre-ionization should be injected when the electric field is high enough in the gap, injection after 80% peak-time can ensure its effectiveness.Then the statistical time delay jitter will be determined by the pre-ionization jitter, which is an intrinsic restriction of the self-triggered switch. However, when the changing rate of the pulsed electric field exceeds a certain value, the breakdown time delay jitter can be partly offset in the formative stage because the formative time delay has an exponential relationship with the electric field. Therefore, lower time jitter can be obtained under pulses with a shorter pulse rise time. In general, the results of the calculation model agree with the experimental results, and the experimental parameters which lead to a low jitter can also be used as a reference.
文摘Carbonate reservoirs in Western China show tremendous exploration and development potential.These have become the key area for oil and gas reserves addition and sustainable resource development for China.Compared to conventional carbonate reservoirs,prediction of this kind of reservoir predominated by secondary storage is much more difficultand presents significant challenges.
文摘This work investigates the pulsed breakdown processes and mechanisms of self-triggered preionized switches with a four-electrode structure in nitrogen through intensified charge coupled device photographs.The diameter of the trigger plane hole mainly determines the switch’s electric field distribution.Two configurations with minimum and maximum trigger plane holes are adopted for comparison.In the switch with a minimum trigger plane hole,the maximum electric field distributes at the surfaces of the main electrodes.Although charged particles in the triggering spark channel cannot drift out,homogeneous discharges can be stimulated from both the cathode and anode surfaces through ultraviolet illumination.Two sub-gaps are likely to break down simultaneously.In the switch with a maximum trigger plane hole,the maximum electric field locates near the trigger electrodes.Discharges in both sub-gaps initiate from the trigger electrodes in the form of a positive or negative streamer.Due to the lower breakdown voltage and electric field threshold for discharge initiation,the cathode side sub-gap breaks down first.The analysis of two extreme examples can be referenced in the future design and improvement of self-triggered four-electrode switches with different trigger electrode structures.
基金supported by grants from the National Key Research and Development Program of China(2021YFF1000301)the National Natural Science Foundation of China(32022065,32272189,and 32130077)+2 种基金the Hainan Yazhou Bay Seed Lab(B21HJ8101)the Agricultural Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciencesthe Central Public-Interest Scientific Institution Basal Research Fund,and Chinese Scholarship Council(CSC).
文摘Maize is a major staple crop widely used as food,animal feed,and raw materials in industrial production.High-density planting is a major factor contributing to the continuous increase of maize yield.However,high planting density usually triggers a shade avoidance response and causes increased plant height and ear height,resulting in lodging and yield loss.Reduced plant height and ear height,more erect leaf angle,reduced tassel branch number,earlier flowering,and strong root system architecture are five key morphological traits required for maize adaption to high-density planting.In this review,we summarize recent advances in deciphering the genetic and molecular mechanisms of maize involved in response to high-density planting.We also discuss some strategies for breeding advanced maize cultivars with superior performance under high-density planting conditions.
基金the Natural Science Foundation of Hunan Province in China(2021JJ20084)and the Science and Technology Innovation Program of Hunan Province(2021RC3020).
文摘Photodynamic therapy(PDT)has emerged as a promising approach for squamous cell carcinoma treatment but hindered by tumor hypoxia,acquired resistance,phototoxicity,and so on.To address these issues,we developed a smart strategy utilizing activable photosensitizers delivered by an aptamer-functionalized DNA probe(ADP).The ADP incorporated an AS1411 aptamer for tumor targeting and a linear antisense oligonucleotide(ASO)for recognition of Survivin mRNA.In the absence of the target,PDT remained quenched,thereby avoiding phototoxicity during circulation and nonselective distribution.With the aid of the aptamer,ADP achieved selective targeting of tumors.Upon internalization,ADP targeted recognized Survivin mRNA,triggering PDT activation,and releasing ASO to down-regulate Survivin expression and reverse tumor resistance.Consequently,the activable photosensitizers exhibited an“AND”logic gate,combining tumor-targeting delivery and tumor-related gene activation,thus enhancing its specificity.Additionally,the incorporation of hemin into the ADP provided catalase activity,converting tumor-abundant H_(2)O_(2) into O_(2),thereby ameliorating tumor hypoxia.The resulting functionalized G-quadruplex/hemin–DNA probe complex demonstrated targeted delivery and activation,minimized side effects,and enhanced PDT efficacy in both xenograft tumor-bearing mice and patient-derived xenograft models.This study offers a unique and promising platform for efficient and safe PDT,thus holding great potential for future clinical translation and improved cancer therapy.
基金supported by the Key Laboratory of Biology,Genetics and Breeding of Japonica Rice in Mid-lower Yangtze River,Ministry of Agriculture and Rural Affairs,China,and the Jiangsu Collaborative Innovation Center for Modern Crop Production,China.Funding for this work was provided by the National Key Research and Development Program of China(2020YFE0202300 and 2021YFD1200504)the National Natural Science Foundation of China(31971910 and 32272115)+1 种基金the National Science Foundation of Jiangsu Province(BK20212010 and BK20230038)the Foundation of Biological Breeding Zhongshan Lab(BM2022008-03,ZSBBL-KY2023-04,and ZSBBL-KY2023-06).
文摘N6-Methyladenosine(m^(6)A)is one of the most abundant modifications of eukaryotic mRNA,but its comprehensive biological functionality remains further exploration.In this study,we identified and characterized a new flowering-promoting gene,EARLY HEADING DATE6(EHD6),in rice.EHD6 encodes an RNA recognition motif(RRM)-containing RNA binding protein that is localized in the non-membranous cytoplasm ribonucleoprotein(RNP)granules and can bind both m^(6)A-modified RNA and unmodified RNA indiscriminately.We found that EHD6 can physically interact with YTH07,a YTH(YT521-B homology)domain-containing m^(6)A reader.We showed that their interaction enhances the binding of an m^(6)A-modified RNA and triggers relocation of a portion of YTH07 from the cytoplasm into RNP granules through phase-separated condensation.Within these condensates,the mRNA of a rice flowering repressor,CONSTANS-like 4(OsCOL4),becomes sequestered,leading to a reduction in its protein abundance and thus accelerated flowering through the Early heading date 1 pathway.Taken together,these results not only shed new light on the molecular mechanism of efficient m^(6)A recognition by the collaboration between an RNA binding protein and YTH family m^(6)A reader,but also uncover the potential for m^(6)A-mediated translation regulation through phaseseparated ribonucleoprotein condensation in rice.
基金supported by the National Natural Science Foundation of China(Grants Nos.41821001,42130208,41825019,41888101,42103072)the National Key Research and Development Program of China(Grant No.2022YFF0800100)。
文摘The carbon cycle plays a pivotal role in regulating Earth’s surface environment through atmospheric-oceanic acid-base and redox processes, functioning as the engine driving the evolution of our planet’s surface. A deep understanding of the carbon cycle’s evolution is thus essential for our understanding of the evolution of our planet’s habitability.
基金the National Natural Science Foundation of China(32270263 to G.L.,32130077 to H.W.,and 32272140 to P.L.)the Shandong Provincial Natural Science Foundation(ZR2022QC095,ZR2020MC023,ZR2022MC019).
文摘Over the past few decades,significant improvements in maize yield have been largely attributed to increased plant density of upright hybrid varieties rather than increased yield per plant.However,dense planting triggers shade avoidance responses(SARs)that optimize light absorption but impair plant vigor and performance,limiting yield improvement through increasing plant density.In this study,we demonstrated that high-density-induced leaf angle narrowing and stem/stalk elongation are largely dependent on phytochrome B(phyB1/B2),the primaryphotoreceptor responsible for perceiving red(R)and far-red(FR)light in maize.We found that maize phyB physically interacts with the LIGULELESS1(LG1),a classical key regulator of leaf angle,to coordinately regulate plant architecture and density tolerance.The abundance of LG1 is significantly increased by phyB under high R:FR light(low density)but rapidly decreases under low R:FR light(high density),correlating with variations in leaf angle and plant height under various densities.In addition,we identified the homeobox transcription factor HB53 as a target co-repressed by both phyB and LG1 but rapidly induced by canopy shade.Genetic and cellular analyses showed that HB53 regulates plant architecture by controlling the elongation and division of ligular adaxial and abaxial cells.Taken together,these findings uncover the phyB-LG1-HB53 regulatory module as a key molecular mechanism governing plant architecture and density tolerance,providing potential genetic targets for breeding maize hybrid varieties suitable for high-density planting.
基金supported by National Natural Science Foundation of China(grant Nos.52106070,52276048)Guangdong Basic and Applied Basic Research Foundation(grant No.2020A1515111014)Fundamental Research Funds for the Central Universities(grant No.FRF-TP-20-058A1,FRF-EYIT-23-07).
文摘Waste heat recovery of high-temperature granules is one of the most promising sustainable energy supply and carbon reduction ways for industry.A moving bed indirect heat exchanger(MBIHE)with inner-migration was proposed for granular heat recovery.Granule migration and the enhanced heat transfer induced by two types of agitators(i.e.,agitator with slanted stick A_(s)and with plow-shaped surface A_(p))in the MBIHE are analyzed based on DEM coupled with CFD.Owing to the effective agitation,the average heat transfer coefficient in the granule side is enhanced to∼3 times compared to that without agitation.The heat recovery efficiency in the moving bed reached more than 70%with the agitations of either A_(s)or A_(p).The heat efficiency of A_(s)is∼7%higher than that of A_(p),but with at least 60%greater rotational torque.To ensure reliable agitation,the A_(p)is suggested to be adopted in the MBIHE to induce granule migration.
文摘Correction:aBI0TECH(2021)2:131-145 https://doi.0rg/10.1007/s42994-021-00038-1 In this article the author's name Fereshteh Jafari was incorrectly written as Feresheeh Jafari.The original article has been corrected.Open Access This article is licensed under a Creative Commons Attribution 4.0 International License,which permits use,sharing,adaptation,distribution and reproduction in any medium or format.
基金support of the Basic Science Center Program of the National Natural Science Foundation of China(NSFC)under Grant no.51788104 and Beijing Natural Science Foundation under Grant no.JQ19005China Postdoctoral Science Foundation Grant no.2021M691713.
文摘Hard-to-dissolve polymers provide next-generation alternatives for high-performance filter materials owing to their intrin-sically high chemical stability,superior mechanical performance,and excellent high-temperature resistance.However,the mass production of hard-to-dissolve nanofibers still remains a critical challenge.A simple,scalable,and low-cost ionic solu-tion blow-spinning method has herein been provided for the large-scale preparation of hard-to-dissolve Nomex polymeric nanofibers with an average diameter of nearly 100 nm.After rapidly dissolving Nomex microfibers in the lithium chloride/dimethylacetamide(LiCl/DMAc)solution system,the conductive solution can be stably and conductivity-independently processed into nanofibers.The method optimizes electrospinning and avoids spinnability degradation and potential safety hazards caused by high electrical conductivity.Owing to nanofibrous structure and high dipole moment,Nomex nanofibrous filters show a stable high filtration efficiency of 99.92%for PM_(0.3) with a low areal density of 4.6 g m^(-2),as well as a low-pressure drop of 189.47 Pa.Moreover,the flame-retardant filter can work at 250°C and 280°C for a long and short time without shrinking or burning,respectively,exhibiting a high filtration efficiency of 99.50%for PM_(0.3-10.0).The outstanding properties and low cost enable the efficient capture of PM from various high-temperature exhausts,making Nomex nanofi-brous membrane an even more ideal industrial-grade air filter than polypropylene,polytetrafluoroethylene,polyimide,and ceramic nanofibrous filters.
基金supported by grants from the National Natural Science Foundation of China(91935301)National Natural Science Foundation of China Joint Program(U1701232)+4 种基金Jiangsu Science and Technology Development Program(BE2021360)Jiangsu Agricultural Science and Technology Innovation Fund Project(SCX(19)1079)Jiangsu Province Agriculture Independent Innovation Fund Project(CX(19)1002)National Key Research and Development Program of China(2016YFD0100903)the Fundamental Research Funds for the Central Universities(JCQY201902).
文摘Plastid-to-nucleus retrograde signaling coordinates nuclear gene expression with chloroplast developmental status and is essential for the photoautotrophic lifestyle of plants.Previous studies have established that tetrapyrrole biosynthesis(TPB)and plastid gene expression(PGE)play essential roles in plastid retrograde signaling during early chloroplast biogenesis;however,their functional relationship remains unknown.In this study,we generated a series of rice TPB-related gun(genome uncoupled)mutants and systematically analyzed their effects on nuclear and plastid gene expression under normal conditions or when subjected to treatments with norflurazon(NF;a noncompetitive inhibitor of carotenoid biosynthesis)and/or lincomycin(Lin;a specific inhibitor of plastid translation).We show that under NF treatment,expression of plastid-encoded polymerase(PEP)-transcribed genes is significantly reduced in the wild type but is derepressed in the TPB-related gun mutants.We further demonstrate that the derepressed expression of PEPtranscribed genes may be caused by increased expression of the PEP core subunit and nuclear-encoded sigma factors and by elevated copy numbers of plastid genome per haploid genome.In addition,we show that expression of photosynthesis-associated nuclear genes(PhANGs)and PEP-transcribed genes is correlated in the rice TPB-related gun mutants,with or without NF or Lin treatment.A similar correlation between PhANGs and PGE is also observed in the Arabidopsis gun4 and gun5 mutants.Moreover,we show that increased expression of PEP-transcribed plastid genes is necessary for the gun phenotype in NF-treated TPB-related gun mutants.Further,we provide evidence that these TPB-related GUN genes act upstream of GUN1 in the regulation of retrograde signaling.Taken together,our results suggest that the TPB-related GUN genes control retrograde plastid signaling by regulating the PGE-dependent retrograde signaling pathway.
基金National Key R&D Program of China(No.2017YFA0505700)Non-Profit Central Research Institute Fund of the Chinese Academy of Medical Sciences(No.2019PT320002)+2 种基金Natural Science Foundation Project of China(No.81820108015)China Postdoctoral Science Foundation(Nos.2020TQ0393,2020M683634XB,and 2021M693926)Chongqing Science and Technology Commission(Nos.cstc2021jcyj-bsh0026 and cstc2021jcyj-bsh0034)
文摘In the last decade,it has become increasingly recognized that a balanced gut microbiota plays an important role in maintaining the health of the host.Numerous clinical and preclinical studies have shown that changes in gut microbiota composition are associated with a variety of neurological diseases,e.g.,Parkinson’s disease,Alzheimer’s disease,and myasthenia gravis.However,the underlying molecular mechanisms are complex and remain unclear.Behavioral phenotypes can be transmitted from humans to animals through gut microbiota transplantation,indicating that the gut microbiota may be an important regulator of neurological diseases.However,further research is required to determine whether animal-based findings can be extended to humans and to elucidate the relevant potential mechanisms by which the gut microbiota regulates neurological diseases.Such investigations may aid in the development of new microbiota-based strategies for diagnosis and treatment and improve the clinical management of neurological disorders.In this review,we describe the dysbiosis of gut microbiota and the corresponding mechanisms in common neurological diseases,and discuss the potential roles that the intestinal microbiome may play in the diagnosis and treatment of neurological disorders.