The use of robots to augment human capabilities and assist in work has long been an aspiration.Robotics has been developing since the 1960s when the first industrial robot was introduced.As technology has advanced,rob...The use of robots to augment human capabilities and assist in work has long been an aspiration.Robotics has been developing since the 1960s when the first industrial robot was introduced.As technology has advanced,robotic-assisted surgery has shown numerous advantages,including more precision,efficiency,minimal invasiveness,and safety than is possible with conventional techniques,which are research hotspots and cutting-edge trends.This article reviewed the history of medical robot development and seminal research papers about current research progress.Taking the autonomous dental implant robotic system as an example,the advantages and prospects of medical robotic systems would be discussed which would provide a reference for future research.展开更多
The distinctive conditions present on the north and south slopes of Mount Qomolangma,along with the intricate variations in the underlying surfaces,result in notable variations in the surface energy flux patterns of t...The distinctive conditions present on the north and south slopes of Mount Qomolangma,along with the intricate variations in the underlying surfaces,result in notable variations in the surface energy flux patterns of the two slopes.In this paper,data from TESEBS(Topographical Enhanced Surface Energy Balance System),remote sensing data from eight cloud-free scenarios,and observational data from nine stations are utilized to examine the fluctuations in the surface heat flux on both slopes.The inclusion of MCD43A3 satellite data enhances the surface albedo,contributing to more accurate simulation outcomes.The model results are validated using observational data.The RMSEs of the net radiation,ground heat,sensible heat,and latent heat flux are 40.73,17.09,33.26,and 30.91 W m^(−2),respectively.The net radiation flux is greater on the south slope and exhibits a rapid decline from summer to autumn.Due to the influence of the monsoon,on the north slope,the maximum sensible heat flux occurs in the pre-monsoon period in summer and the maximum latent heat flux occurs during the monsoon.The south slope experiences the highest latent heat flux in summer.The dominant flux on the north slope is sensible heat,while it is latent heat on the south slope.The seasonal variations in the ground heat flux are more pronounced on the south slope than on the north slope.Except in summer,the ground heat flux on the north slope surpasses that on the south slope.展开更多
Type Ⅳ interferon(IFN-υ)is a recently discovered cytokine crucial for host defense against viral infections.However,the role and mechanisms of IFN-υin bacterial infections remain unexplored.This study investigated ...Type Ⅳ interferon(IFN-υ)is a recently discovered cytokine crucial for host defense against viral infections.However,the role and mechanisms of IFN-υin bacterial infections remain unexplored.This study investigated the antibacterial and antiviral functions and mechanisms of grass carp(Ctenopharyngodon idella)IFN-υ(CiIFN-υ)both in vivo and in vitro.The CiIFN-υgene was first identified and characterized in grass carp.Subsequently,the immune expression of CiIFN-υsignificantly increased following bacterial challenge,indicating its response to bacterial infections.The eukaryotic recombinant expression plasmid of CiIFN-υwas then constructed and transfected into fathead minnow(FHM)cells.Supernatants were collected and incubated with four bacterial strains,followed by plate spreading and colony counting.Results indicated that CiIFN-υexhibited more potent antibacterial activity against gram-negative bacteria compared to gram-positive bacteria and aggregated gram-negative bacteria but not gram-positive bacteria.In vivo experiments further confirmed the antibacterial function,showing high survival rates,low tissue edema and damage,reduced tissue bacterial load,and elevated proinflammatory response at the early stages of bacterial infection.In addition,the antiviral function of CiIFN-υwas confirmed through in vitro and in vivo experiments,including crystal violet staining,survival rates,tissue viral burden,and reverse transcription-quantitative real-time polymerase chain reaction(RT-qPCR).This study highlights the antibacterial function and preliminary mechanism of IFN-υ,demonstrating that IFN-υpossesses dual functions against bacterial and viral infections.展开更多
This study focused on the investigation of the edge effect of diamond films deposited by microwave plasma chemical vapor de-position.Substrate bulge height△h is a factor that affects the edge effect,and it was used t...This study focused on the investigation of the edge effect of diamond films deposited by microwave plasma chemical vapor de-position.Substrate bulge height△h is a factor that affects the edge effect,and it was used to simulate plasma and guide the diamond-film deposition experiments.Finite-element software COMSOL Multiphysics was used to construct a multiphysics(electromagnetic,plasma,and fluid heat transfer fields)coupling model based on electron collision reaction.Raman spectroscopy and scanning electron microscopy were performed to characterize the experimental growth and validate the model.The simulation results reflected the experimental trends observed.Plasma discharge at the edge of the substrate accelerated due to the increase in△h(△h=0-3 mm),and the values of electron density(n_(c)),molar concentration of H(C_(H)),and molar concentration of CH_(3)(C_(CH_(3)))doubled at the edge(for the special concave sample with△h=−1 mm,the active chemical groups exhibited a decreased molar concentration at the edge of the substrate).At=0-3 mm,a high diamond growth rate and a large diamond grain size were observed at the edge of the substrate,and their values increased with.The uniformity of film thickness decreased with.The Raman spectra of all samples revealed the first-order characteristic peak of dia-mond near 1332 cm^(−1).When△h=−1 mm,tensile stress occurred in all regions of the film.When△h=1-3 mm,all areas in the film ex-hibited compressive stress.展开更多
The low-frequency oscillation(LFO)has occurred in the train-network system due to the introduction of the power electronics of the trains.The modeling and analyzing method in current researches based on electrified ra...The low-frequency oscillation(LFO)has occurred in the train-network system due to the introduction of the power electronics of the trains.The modeling and analyzing method in current researches based on electrified railway unilateral power supply system are not suitable for the LFO analysis in a bilateral power supply system,where the trains are supplied by two traction substations.In this work,based on the single-input and single-output impedance model of China CRH5 trains,the node admittance matrices of the train-network system both in unilateral and bilateral power supply modes are established,including three-phase power grid,traction transformers and traction network.Then the modal analysis is used to study the oscillation modes and propagation characteristics of the unilateral and bilateral power supply systems.Moreover,the influence of the equivalent inductance of the power grid,the length of the transmission line,and the length of the traction network are analyzed on the critical oscillation mode of the bilateral power supply system.Finally,the theoretical analysis results are verified by the time-domain simulation model in MATLAB/Simulink.展开更多
This study isolated and purified strain 431 from an animal probiotic product.Through staining and microscopic examination,colony morphology analysis,biochemical reaction tests,and 16S rDNA sequence alignment,the strai...This study isolated and purified strain 431 from an animal probiotic product.Through staining and microscopic examination,colony morphology analysis,biochemical reaction tests,and 16S rDNA sequence alignment,the strain was identified and named Brevibacterium aureus 431.The study focused on the production of biosurfactants by strain 431,and antibacterial activity tests were conducted on the strain and its secondary metabolites.The results showed that strain 431 exhibited no resistance to 10 commonly used drugs,and its concentrated secondary metabolites were highly sensitive to the indicator bacterium Escherichia coli.Oral administration of strain 431 to BALB/c mice resulted in normal mental state,diet,and bowel movements,with no signs of illness or death,indicating that strain 431 is highly safe and non-pathogenic to mice.The study suggests that Brevibacterium aureus 431 has significant research value as a new source of actinomycetes and that its secondary metabolites have potential application value in the development of antibacterial drugs.展开更多
In this study, six bacterial strains were isolated from the sediment, probiotic fermentation products, and lake sediments, they were identified as Bacillus amyloliquefaciens using genetic evolution analysis, which wer...In this study, six bacterial strains were isolated from the sediment, probiotic fermentation products, and lake sediments, they were identified as Bacillus amyloliquefaciens using genetic evolution analysis, which were named B3, B4, B5, XD3, YF6, and YF8. The comparison of the antibacterial activity, hemolytic activity, and antibiotic sensitivity of six Bacillus amyloliquefaciens strains laid a foundation for the development and application of antimicrobial peptide products. A surface activity assay was used to determine the production of biosurfactants in six Bacillus amyloliquefaciens strains. With Staphylococcus aureus and Escherichia coli as indicator bacteria, their antibacterial activity was determined using the agar diffusion method;the same diffusion method was used to determine the antibiotic susceptibility of Bacillus amyloliquefaciens. The results showed that the six Bacillus amyloliquefaciens strains had obvious biosurface activity, and the bacteria inhibited Staphylococcus aureus and Escherichia coli, from strong to weak: YF8, XD3, B3, B4, YF6, and B5. Strain YF8 had the best broad-spectrum bacteriostatic effect, followed by strain XD3. All Bacillus amyloliquefaciens strains were susceptible to 16 common drugs, except for Bacillus amyloliquefaciens strain YF8, which was intermediate to neomycin. The study shows that Bacillus amyloliquefaciens and secondary metabolites have the ability to produce a variety of active peptides, exert a certain inhibitory effect on common pathogens, and have the potential to develop as animal probiotics.展开更多
The high terrain of the Tibetan Plateau(TP)has a very important impact on the weather and climate of China,East Asia,South Asia,and even the Northern Hemisphere.However,in recent years,the reasons for the decrease in ...The high terrain of the Tibetan Plateau(TP)has a very important impact on the weather and climate of China,East Asia,South Asia,and even the Northern Hemisphere.However,in recent years,the reasons for the decrease in precipitation in the southeastern edge of the plateau have resulted in cutting-edge research regarding the impact of the TP and its surrounding areas on downstream weather and climate.In this study,the spatial and temporal distribution of surface heat flux and precipitation were analyzed from 1998 to 2022,and the possible mechanism of the decrease of precipitation in the eastern edge of the plateau is explored.The main conclusions are as follows:The annual average sensible heat flux in the TP and its east side is positive,with an average of 33.73 W/m^(2).The annual average latent heat flux is positive,with an average of 42.71 W/m^(2).Precipitation has a similar annual average and seasonal distribution,with modest amounts in the northwest and substantial amounts in the southeast.The average annual accumulated precipitation is 670.69 mm.The first mode of the Empirical Orthogonal Function(EOF)shows that sensible heat flux decreases first,then increases,and then finally decreases during 1998–2022.The modes show the opposite trend in middle part of the plateau.The latent heat flux initially decreases,then increases,and finally decreases in the western plateau and near Sichuan Basin.The mode,however,displays the opposite tendency throughout the rest of the region.The precipitation in the north and south sides of the plateau has decreased since 2013,which is consistent with the changing trend of sensible heat flux.In the rest of the region,the change trend is not obvious.The sensible heat of the main body of the plateau and its east side and Sichuan Basin is negatively correlated with precipitation,that is,when sensible heat flux of the main body of the plateau and its east side and Sichuan Basin is more(less),local precipitation is less(more).The latent heat of the main body of the plateau and its east side,Sichuan Basin is positively correlated with precipitation,indicating that when latent heat flux of the main body of the plateau and its east side,Sichuan Basin is more(less),local precipitation is more(less).展开更多
Alzheimer’s disease(AD)is a typical neurodegenerative disease that leads to irreversible neuronal degeneration,and effective treatment remains elusive due to the unclear mechanism.We utilized biocompatible mesenchyma...Alzheimer’s disease(AD)is a typical neurodegenerative disease that leads to irreversible neuronal degeneration,and effective treatment remains elusive due to the unclear mechanism.We utilized biocompatible mesenchymal stem cell-derived extracellular vesicles as carriers loaded with the CB2 target medicine AM1241(EVs-AM1241)to protect against neurodegenerative progression and neuronal function in AD model mice.According to the results,EVs-AM1241 were successfully constructed and exhibited better bioavailability and therapeutic effects than bare AM1241.The Morris water maze(MWM)and fear conditioning tests revealed that the learning and memory of EVs-AM1241-treated model mice were significantly improved.In vivo electrophysiological recording of CA1 neurons indicated enhanced response to an auditory conditioned stimulus following fear learning.Immunostaining and Western blot analysis showed that amyloid plaque deposition and amyloidβ(Aβ)-induced neuronal apoptosis were significantly suppressed by EVs-AM1241.Moreover,EVs-AM1241 increased the number of neurons and restored the neuronal cytoskeleton,indicating that they enhanced neuronal regeneration.RNA sequencing revealed that EVs-AM1241 facilitated Aβphagocytosis,promoted neurogenesis and ultimately improved learning and memory through the calcium-Erk signaling pathway.Our study showed that EVs-AM1241 efficiently reversed neurodegenerative pathology and enhanced neurogenesis in modelmice,indicating that they are very promising particles for treating AD.展开更多
Vanadium flow battery （VFB） is a fast going and promising system for large-scale stationary energy stor- age. However, drawbacks such as low power density and narrow temperature window caused by poor catalytic activ...Vanadium flow battery （VFB） is a fast going and promising system for large-scale stationary energy stor- age. However, drawbacks such as low power density and narrow temperature window caused by poor catalytic activity of graphite felt （GF） electrodes limit its worldwide application. In this paper, bismuth, as a low-cost, no-toxic and high-activity electrocatalyst, is used to modify the thermal activated GF （TGF） via a facile hydrothermal method. Bismuth can effectively inhibit the side reaction of hydrogen evolution in wide temperature range, while promoting the V2＋/V3＋ redox reaction. As a result, the VFB assembled with Bi/TGF as negative electrode demonstrates outstanding rate performance under the current density up to 400 mAcm-2, as well as a long-term stability over 600 charging/discharging cycles at a high cur- rent density of 150mA cm-2. Moreover, it also shows excellent temperature adaptability from -10 ℃ to 50 ℃ and high durability for life test at the temperature of 50 ℃.展开更多
高表达免疫检查点分子程序性死亡受体-配体1(programmed death ligand-1,PD-L1)是肿瘤细胞逃避机体免疫监视的重要途径。PD-L1的表达受到转录水平、翻译水平和翻译后修饰水平等的调控。近年来,PD-L1翻译后修饰逐渐成为PD-L1研究领域的...高表达免疫检查点分子程序性死亡受体-配体1(programmed death ligand-1,PD-L1)是肿瘤细胞逃避机体免疫监视的重要途径。PD-L1的表达受到转录水平、翻译水平和翻译后修饰水平等的调控。近年来,PD-L1翻译后修饰逐渐成为PD-L1研究领域的热点。PD-L1的翻译后修饰包括糖基化、泛素化、磷酸化、棕榈酰化和乙酰化等,可影响PD-L1的稳定性及生物学功能。本文将对该领域的研究进展进行综述,以期为肿瘤免疫治疗研究提供新思路。展开更多
Apple is one of the most important fruit trees in temperate zones, and is cultivated widely throughout the world. Drought stress affects the normal growth of apple tree, and further affects fruit yield and quality. Th...Apple is one of the most important fruit trees in temperate zones, and is cultivated widely throughout the world. Drought stress affects the normal growth of apple tree, and further affects fruit yield and quality. The present study examined the effects of drought on photosynthesis and water use efficiency (WUE) of two apple cultivars (Honeycrisp and Yanfu 3) that differ in drought tolerance. The results showed that the photosynthetic rate decreased in response to drought stress for both cultivars, with significant differences in intensity. Values for net photosynthetic rate (Pn) in stressed Yanfu 3 remained significantly lower than in the controls, while, for Honeycrisp, only a slight drop in photosynthesis. Similarly, stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (Tr) were markedly reduced in Yanfu 3 under drought stress. However, Honeycrisp showed only minor changes. Under drought stress, the contents of Chl a, Chl b and Chl t in Yanfu 3 were all decreased significantly compared with the control. However, little difference in Honeycrisp was noted between stressed plants and controls. Values for WUE in stressed Yanfu 3 remained higher than in the controls from day 3 until the end of the experiment, while no significant difference was observed in Honeycrisp. Furthermore, Honeycrisp also exhibited superior physiological traits, as indicated by its anatomical and morphological characteristics. Therefore, we conclude that the superior drought tolerance of Honeycrisp was due to its anatomical and morphological characteristics, which possibly contributed to the maintenance of higher photosynthetic capacity than Yanfu 3.展开更多
Speleothem carbonates are precipitated continuously from inorganic carbon dissolved in seepage water infiltrating from the land surface,that reflects a mixture of atmospheric CO_2,respired soil carbon,and epikarst sou...Speleothem carbonates are precipitated continuously from inorganic carbon dissolved in seepage water infiltrating from the land surface,that reflects a mixture of atmospheric CO_2,respired soil carbon,and epikarst sources,each with distinct δ^(13)C values.To aid in deconvolving these signatures,soil samples were collected above the Blue Spring cave system in Sparta,Tennessee,USA and subjected to a series of incubation experiments,in order to constrain the correlation between CO_2respiration rates and soil moisture.This relationship is used to parameterize a simple mixing model which predicts the relationship between δ^(13)C and soil moisture in fluids infiltrating into the underlying cave system.展开更多
Joint inversion for crustal velocity structure using only surface wave dispersion and receiver function data often suffers the non-unique solution problem due to lack of P wave velocity constraint in the data.Here we ...Joint inversion for crustal velocity structure using only surface wave dispersion and receiver function data often suffers the non-unique solution problem due to lack of P wave velocity constraint in the data.Here we developed a method for measuring PmP travel time using teleseismic S wave waveform.The major improvement by this method over the previous one-layer-crust search method is its use of a more realistic multi-layer-crust(MLC)velocity model in the study region based on available information.Numerical tests show that compared with the previous search method the MLC search method is faster and more reliable and accurate.One limit of the MLC search method is the requirement of a multi-layer background model,thus this method might not be applicable in regions where the velocity structure is unknown.Nevertheless,our numerical tests show that the MLC search method is robust in the sense that small deviations of the background model from the true velocity model do not influence the results severely.We applied the MLC search method to data from a temporary linear array across the Wabash Valley Seismic Zone in the central USA.We obtained 157 PmP travel-time measurements that show lateral crustal structure variation in the region.The measurements provide additional constraints in joint inversion for crustal velocity structure in this seismically active region.展开更多
Amino acid transporters( AATs) play an important role in transport process of various amino acids,which are indispensable in plant growth and development,while many putative AATs have been identified and the complete ...Amino acid transporters( AATs) play an important role in transport process of various amino acids,which are indispensable in plant growth and development,while many putative AATs have been identified and the complete genomic sequences of the important plants have already been completed by splicing and assembling. There is still little knowledge about the expression,regulation and various biological functions of AATs in plants,including the major food crops. This study mainly reviewed the expression,regulation and various biological functions of AATs in plants,and the application of AATs in crop genetic improvement was also prospected. Thus,this review will provide important information for genetic improvement of staple food crops in plants.展开更多
Starch and the storage proteins are the main nutritious substances in crop grains,and their composition and content in grains play a decisive role in the grain quality of rice and other staple food crops.This review h...Starch and the storage proteins are the main nutritious substances in crop grains,and their composition and content in grains play a decisive role in the grain quality of rice and other staple food crops.This review has mainly summarized the new advances in the expression regulation of starch and storage protein synthesis related genes in rice grains.Moreover,the challenges of the starch and storage protein synthesis substances in rice genetic improvement were also discussed.This review will provide important information for genetic improvement of grain quality in rice and,potentially,other staple cereals.展开更多
As the most prevalent and reversible internal epigenetic modification in eukaryotic mRNAs,N6-methyladenosine(m^(6)A)post-transcriptionally regulates the processing and metabolism of mRNAs involved in diverse biologica...As the most prevalent and reversible internal epigenetic modification in eukaryotic mRNAs,N6-methyladenosine(m^(6)A)post-transcriptionally regulates the processing and metabolism of mRNAs involved in diverse biological processes.m^(6)A modification is regulated by m^(6)A writers,erasers,and readers.Emerging evidence suggests that m^(6)A modification plays essential roles in modulating the cell-fate transition of embryonic stem cells.Mechanistic investigation of embryonic stem cell maintenance and differentiation is critical for understanding early embryonic development,which is also the premise for the application of embryonic stem cells in regenerative medicine.This review highlights the current knowledge of m^(6)A modification and its essential regulatory contribution to the cell fate transition of mouse and human embryonic stem cells.展开更多
Stem cell-derived spinal cord organoids(SCOs)have revolutionised the study of spinal cord development and disease mechanisms,offering a three-dimensional model that recapitulates the complexity of native tissue.This r...Stem cell-derived spinal cord organoids(SCOs)have revolutionised the study of spinal cord development and disease mechanisms,offering a three-dimensional model that recapitulates the complexity of native tissue.This review synthesises recent advancements in SCO technology,highlighting their role in modelling spinal cord morphogenesis and their application in neurodegenerative disease research.We discuss the methodological breakthroughs in inducing regional specification and cellular diversity within SCOs,which have enhanced their predictive ability for drug screening and their relevance in mimicking pathological conditions such as neurodegenerative diseases and neuromuscular disorders.Despite these strides,challenges in achieving vascularisation and mature neuronal integration persist.The future of SCOs lies in addressing these limitations,potentially leading to transformative impactions in regenerative medicine and therapeutic development.展开更多
基金supported by the National Natural Science Foundation of China[grant number 81970987].
文摘The use of robots to augment human capabilities and assist in work has long been an aspiration.Robotics has been developing since the 1960s when the first industrial robot was introduced.As technology has advanced,robotic-assisted surgery has shown numerous advantages,including more precision,efficiency,minimal invasiveness,and safety than is possible with conventional techniques,which are research hotspots and cutting-edge trends.This article reviewed the history of medical robot development and seminal research papers about current research progress.Taking the autonomous dental implant robotic system as an example,the advantages and prospects of medical robotic systems would be discussed which would provide a reference for future research.
基金financially supported by the National Natural Science Foundation of China[grant number 42230610]the Second Tibetan Plateau Scientific Expedition and Research(STEP)program[grant number 2019QZKK0103]+1 种基金the Natural Science Foundation of Sichuan Province[grant number 2022NSFSC0217]the Scientific Research Project of Chengdu University of Information Technology[grant number KYTZ201721].
文摘The distinctive conditions present on the north and south slopes of Mount Qomolangma,along with the intricate variations in the underlying surfaces,result in notable variations in the surface energy flux patterns of the two slopes.In this paper,data from TESEBS(Topographical Enhanced Surface Energy Balance System),remote sensing data from eight cloud-free scenarios,and observational data from nine stations are utilized to examine the fluctuations in the surface heat flux on both slopes.The inclusion of MCD43A3 satellite data enhances the surface albedo,contributing to more accurate simulation outcomes.The model results are validated using observational data.The RMSEs of the net radiation,ground heat,sensible heat,and latent heat flux are 40.73,17.09,33.26,and 30.91 W m^(−2),respectively.The net radiation flux is greater on the south slope and exhibits a rapid decline from summer to autumn.Due to the influence of the monsoon,on the north slope,the maximum sensible heat flux occurs in the pre-monsoon period in summer and the maximum latent heat flux occurs during the monsoon.The south slope experiences the highest latent heat flux in summer.The dominant flux on the north slope is sensible heat,while it is latent heat on the south slope.The seasonal variations in the ground heat flux are more pronounced on the south slope than on the north slope.Except in summer,the ground heat flux on the north slope surpasses that on the south slope.
基金supported by the Biological Breeding-Major Projects(2023ZD04065)。
文摘Type Ⅳ interferon(IFN-υ)is a recently discovered cytokine crucial for host defense against viral infections.However,the role and mechanisms of IFN-υin bacterial infections remain unexplored.This study investigated the antibacterial and antiviral functions and mechanisms of grass carp(Ctenopharyngodon idella)IFN-υ(CiIFN-υ)both in vivo and in vitro.The CiIFN-υgene was first identified and characterized in grass carp.Subsequently,the immune expression of CiIFN-υsignificantly increased following bacterial challenge,indicating its response to bacterial infections.The eukaryotic recombinant expression plasmid of CiIFN-υwas then constructed and transfected into fathead minnow(FHM)cells.Supernatants were collected and incubated with four bacterial strains,followed by plate spreading and colony counting.Results indicated that CiIFN-υexhibited more potent antibacterial activity against gram-negative bacteria compared to gram-positive bacteria and aggregated gram-negative bacteria but not gram-positive bacteria.In vivo experiments further confirmed the antibacterial function,showing high survival rates,low tissue edema and damage,reduced tissue bacterial load,and elevated proinflammatory response at the early stages of bacterial infection.In addition,the antiviral function of CiIFN-υwas confirmed through in vitro and in vivo experiments,including crystal violet staining,survival rates,tissue viral burden,and reverse transcription-quantitative real-time polymerase chain reaction(RT-qPCR).This study highlights the antibacterial function and preliminary mechanism of IFN-υ,demonstrating that IFN-υpossesses dual functions against bacterial and viral infections.
基金supported by the National Key Research and Development Program(No.2019YFE03100200)the State Key Lab for Advanced Metals and Materials,the Fund of National Key Laboratory of Solid-State Microwave Devices and Circuits,the National Natural Science Foundation of China(No.52102034)the Or-ganized Research Fund of North China University of Tech-nology(No.2023YZZKY12).The authors are very grateful for the financial support of these institutions.
文摘This study focused on the investigation of the edge effect of diamond films deposited by microwave plasma chemical vapor de-position.Substrate bulge height△h is a factor that affects the edge effect,and it was used to simulate plasma and guide the diamond-film deposition experiments.Finite-element software COMSOL Multiphysics was used to construct a multiphysics(electromagnetic,plasma,and fluid heat transfer fields)coupling model based on electron collision reaction.Raman spectroscopy and scanning electron microscopy were performed to characterize the experimental growth and validate the model.The simulation results reflected the experimental trends observed.Plasma discharge at the edge of the substrate accelerated due to the increase in△h(△h=0-3 mm),and the values of electron density(n_(c)),molar concentration of H(C_(H)),and molar concentration of CH_(3)(C_(CH_(3)))doubled at the edge(for the special concave sample with△h=−1 mm,the active chemical groups exhibited a decreased molar concentration at the edge of the substrate).At=0-3 mm,a high diamond growth rate and a large diamond grain size were observed at the edge of the substrate,and their values increased with.The uniformity of film thickness decreased with.The Raman spectra of all samples revealed the first-order characteristic peak of dia-mond near 1332 cm^(−1).When△h=−1 mm,tensile stress occurred in all regions of the film.When△h=1-3 mm,all areas in the film ex-hibited compressive stress.
基金This work was supported by the Applied Basic Research Program of Science and Technology Plan Project of Sichuan Province of China(No.2020YJ0252).
文摘The low-frequency oscillation(LFO)has occurred in the train-network system due to the introduction of the power electronics of the trains.The modeling and analyzing method in current researches based on electrified railway unilateral power supply system are not suitable for the LFO analysis in a bilateral power supply system,where the trains are supplied by two traction substations.In this work,based on the single-input and single-output impedance model of China CRH5 trains,the node admittance matrices of the train-network system both in unilateral and bilateral power supply modes are established,including three-phase power grid,traction transformers and traction network.Then the modal analysis is used to study the oscillation modes and propagation characteristics of the unilateral and bilateral power supply systems.Moreover,the influence of the equivalent inductance of the power grid,the length of the transmission line,and the length of the traction network are analyzed on the critical oscillation mode of the bilateral power supply system.Finally,the theoretical analysis results are verified by the time-domain simulation model in MATLAB/Simulink.
基金supported by the Basic Scientific Program of the Institute of Atmospheric Physics supporting the 14th Five-Year Plan[Grant No.7-224151]Youth Innovation Team of China Meteorological Administration[Grant No.CMA2023QN10]+4 种基金the National Natural Science Foundation of China[Grant Nos.42175010,41965010,U223321842275010]Beijing Municipal Science and Technology Commission[Grant No.Z221100005222012]the Department of Science and Technology of Hebei Province[Grant No.22375404D]the Open subjects of the Key Open Laboratory of Cloud Physical Environment,China Meteorological Administration[Grant No.2020Z00715]。
基金Self-funded Science and Technology Innovation Project of Foshan City(220001005797)Foshan University Innovation and Entrepreneurship Training Program for College Students in 2023+2 种基金Foshan City Social Science Planning Project(2024-GJ037)Basic and Applied Basic Research Foundation of Guangdong Province(2022A1515140052)Innovation Project of Guangdong Graduate Education(2022JGXM129,2022JGXM128,2023ANLK-080)。
文摘This study isolated and purified strain 431 from an animal probiotic product.Through staining and microscopic examination,colony morphology analysis,biochemical reaction tests,and 16S rDNA sequence alignment,the strain was identified and named Brevibacterium aureus 431.The study focused on the production of biosurfactants by strain 431,and antibacterial activity tests were conducted on the strain and its secondary metabolites.The results showed that strain 431 exhibited no resistance to 10 commonly used drugs,and its concentrated secondary metabolites were highly sensitive to the indicator bacterium Escherichia coli.Oral administration of strain 431 to BALB/c mice resulted in normal mental state,diet,and bowel movements,with no signs of illness or death,indicating that strain 431 is highly safe and non-pathogenic to mice.The study suggests that Brevibacterium aureus 431 has significant research value as a new source of actinomycetes and that its secondary metabolites have potential application value in the development of antibacterial drugs.
基金2024 Foshan City Social Science Planning Project(2024-GJ037)2023 Education Research and Reform Project of the Online Open Course Alliance in the Guangdong-Hong Kong-Macao Greater Bay Area+3 种基金2023 Foshan University Innovation and Entrepreneurship Training Program for College Students2022 Basic and Applied Basic Research Foundation of Guangdong Province(2022A1515140052)2022 Self-Funded Science and Technology Innovation Project of Foshan City(220001005797)2022 Innovation Project of Guangdong Graduate Education(2022JGXM129,2022JGXM128)and 2023(2023ANLK-080)。
文摘In this study, six bacterial strains were isolated from the sediment, probiotic fermentation products, and lake sediments, they were identified as Bacillus amyloliquefaciens using genetic evolution analysis, which were named B3, B4, B5, XD3, YF6, and YF8. The comparison of the antibacterial activity, hemolytic activity, and antibiotic sensitivity of six Bacillus amyloliquefaciens strains laid a foundation for the development and application of antimicrobial peptide products. A surface activity assay was used to determine the production of biosurfactants in six Bacillus amyloliquefaciens strains. With Staphylococcus aureus and Escherichia coli as indicator bacteria, their antibacterial activity was determined using the agar diffusion method;the same diffusion method was used to determine the antibiotic susceptibility of Bacillus amyloliquefaciens. The results showed that the six Bacillus amyloliquefaciens strains had obvious biosurface activity, and the bacteria inhibited Staphylococcus aureus and Escherichia coli, from strong to weak: YF8, XD3, B3, B4, YF6, and B5. Strain YF8 had the best broad-spectrum bacteriostatic effect, followed by strain XD3. All Bacillus amyloliquefaciens strains were susceptible to 16 common drugs, except for Bacillus amyloliquefaciens strain YF8, which was intermediate to neomycin. The study shows that Bacillus amyloliquefaciens and secondary metabolites have the ability to produce a variety of active peptides, exert a certain inhibitory effect on common pathogens, and have the potential to develop as animal probiotics.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(Grant No.2019QZKK0103)the National Natural Science Foundation of China(Grant No.42230610)+2 种基金the Natural Science Foundation of Sichuan Province(Grant No.2022NSFSC0217)National key research and development program of China(2017YFC1505702)Scientific Research Project of Chengdu University of Information Technology(KYTZ201721).
文摘The high terrain of the Tibetan Plateau(TP)has a very important impact on the weather and climate of China,East Asia,South Asia,and even the Northern Hemisphere.However,in recent years,the reasons for the decrease in precipitation in the southeastern edge of the plateau have resulted in cutting-edge research regarding the impact of the TP and its surrounding areas on downstream weather and climate.In this study,the spatial and temporal distribution of surface heat flux and precipitation were analyzed from 1998 to 2022,and the possible mechanism of the decrease of precipitation in the eastern edge of the plateau is explored.The main conclusions are as follows:The annual average sensible heat flux in the TP and its east side is positive,with an average of 33.73 W/m^(2).The annual average latent heat flux is positive,with an average of 42.71 W/m^(2).Precipitation has a similar annual average and seasonal distribution,with modest amounts in the northwest and substantial amounts in the southeast.The average annual accumulated precipitation is 670.69 mm.The first mode of the Empirical Orthogonal Function(EOF)shows that sensible heat flux decreases first,then increases,and then finally decreases during 1998–2022.The modes show the opposite trend in middle part of the plateau.The latent heat flux initially decreases,then increases,and finally decreases in the western plateau and near Sichuan Basin.The mode,however,displays the opposite tendency throughout the rest of the region.The precipitation in the north and south sides of the plateau has decreased since 2013,which is consistent with the changing trend of sensible heat flux.In the rest of the region,the change trend is not obvious.The sensible heat of the main body of the plateau and its east side and Sichuan Basin is negatively correlated with precipitation,that is,when sensible heat flux of the main body of the plateau and its east side and Sichuan Basin is more(less),local precipitation is less(more).The latent heat of the main body of the plateau and its east side,Sichuan Basin is positively correlated with precipitation,indicating that when latent heat flux of the main body of the plateau and its east side,Sichuan Basin is more(less),local precipitation is more(less).
基金supported by the National Key Research and Development Program (grant no. 2021YFA1101301)the National Natural Science Foundation of China (grant no. 82225027, 82271419, 81820108013, 62127810, 81901902)+1 种基金Shanghai Rising-Star Program (grant no. 22QA1408200)the Fundamental Research Funds for the Central Universities(no. 22120220555, no. 22120230292, no. 22120230138)
文摘Alzheimer’s disease(AD)is a typical neurodegenerative disease that leads to irreversible neuronal degeneration,and effective treatment remains elusive due to the unclear mechanism.We utilized biocompatible mesenchymal stem cell-derived extracellular vesicles as carriers loaded with the CB2 target medicine AM1241(EVs-AM1241)to protect against neurodegenerative progression and neuronal function in AD model mice.According to the results,EVs-AM1241 were successfully constructed and exhibited better bioavailability and therapeutic effects than bare AM1241.The Morris water maze(MWM)and fear conditioning tests revealed that the learning and memory of EVs-AM1241-treated model mice were significantly improved.In vivo electrophysiological recording of CA1 neurons indicated enhanced response to an auditory conditioned stimulus following fear learning.Immunostaining and Western blot analysis showed that amyloid plaque deposition and amyloidβ(Aβ)-induced neuronal apoptosis were significantly suppressed by EVs-AM1241.Moreover,EVs-AM1241 increased the number of neurons and restored the neuronal cytoskeleton,indicating that they enhanced neuronal regeneration.RNA sequencing revealed that EVs-AM1241 facilitated Aβphagocytosis,promoted neurogenesis and ultimately improved learning and memory through the calcium-Erk signaling pathway.Our study showed that EVs-AM1241 efficiently reversed neurodegenerative pathology and enhanced neurogenesis in modelmice,indicating that they are very promising particles for treating AD.
基金financial support from the National Natural Science Foundation of China (No. 21576154)the Open Fund of The State Key Laboratory of Refractories and Metallurgy (No. G201809)the Shenzhen Basic Research Project (Nos. JCYJ20170412170756603 and JCYJ20170307152754218)
文摘Vanadium flow battery （VFB） is a fast going and promising system for large-scale stationary energy stor- age. However, drawbacks such as low power density and narrow temperature window caused by poor catalytic activity of graphite felt （GF） electrodes limit its worldwide application. In this paper, bismuth, as a low-cost, no-toxic and high-activity electrocatalyst, is used to modify the thermal activated GF （TGF） via a facile hydrothermal method. Bismuth can effectively inhibit the side reaction of hydrogen evolution in wide temperature range, while promoting the V2＋/V3＋ redox reaction. As a result, the VFB assembled with Bi/TGF as negative electrode demonstrates outstanding rate performance under the current density up to 400 mAcm-2, as well as a long-term stability over 600 charging/discharging cycles at a high cur- rent density of 150mA cm-2. Moreover, it also shows excellent temperature adaptability from -10 ℃ to 50 ℃ and high durability for life test at the temperature of 50 ℃.
文摘高表达免疫检查点分子程序性死亡受体-配体1(programmed death ligand-1,PD-L1)是肿瘤细胞逃避机体免疫监视的重要途径。PD-L1的表达受到转录水平、翻译水平和翻译后修饰水平等的调控。近年来,PD-L1翻译后修饰逐渐成为PD-L1研究领域的热点。PD-L1的翻译后修饰包括糖基化、泛素化、磷酸化、棕榈酰化和乙酰化等,可影响PD-L1的稳定性及生物学功能。本文将对该领域的研究进展进行综述,以期为肿瘤免疫治疗研究提供新思路。
文摘Apple is one of the most important fruit trees in temperate zones, and is cultivated widely throughout the world. Drought stress affects the normal growth of apple tree, and further affects fruit yield and quality. The present study examined the effects of drought on photosynthesis and water use efficiency (WUE) of two apple cultivars (Honeycrisp and Yanfu 3) that differ in drought tolerance. The results showed that the photosynthetic rate decreased in response to drought stress for both cultivars, with significant differences in intensity. Values for net photosynthetic rate (Pn) in stressed Yanfu 3 remained significantly lower than in the controls, while, for Honeycrisp, only a slight drop in photosynthesis. Similarly, stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (Tr) were markedly reduced in Yanfu 3 under drought stress. However, Honeycrisp showed only minor changes. Under drought stress, the contents of Chl a, Chl b and Chl t in Yanfu 3 were all decreased significantly compared with the control. However, little difference in Honeycrisp was noted between stressed plants and controls. Values for WUE in stressed Yanfu 3 remained higher than in the controls from day 3 until the end of the experiment, while no significant difference was observed in Honeycrisp. Furthermore, Honeycrisp also exhibited superior physiological traits, as indicated by its anatomical and morphological characteristics. Therefore, we conclude that the superior drought tolerance of Honeycrisp was due to its anatomical and morphological characteristics, which possibly contributed to the maintenance of higher photosynthetic capacity than Yanfu 3.
基金supported by the US National Science Foundation, project EAR-1600931
文摘Speleothem carbonates are precipitated continuously from inorganic carbon dissolved in seepage water infiltrating from the land surface,that reflects a mixture of atmospheric CO_2,respired soil carbon,and epikarst sources,each with distinct δ^(13)C values.To aid in deconvolving these signatures,soil samples were collected above the Blue Spring cave system in Sparta,Tennessee,USA and subjected to a series of incubation experiments,in order to constrain the correlation between CO_2respiration rates and soil moisture.This relationship is used to parameterize a simple mixing model which predicts the relationship between δ^(13)C and soil moisture in fluids infiltrating into the underlying cave system.
基金supported by US NSF grants EAR-1249701 and EAR-1661519.
文摘Joint inversion for crustal velocity structure using only surface wave dispersion and receiver function data often suffers the non-unique solution problem due to lack of P wave velocity constraint in the data.Here we developed a method for measuring PmP travel time using teleseismic S wave waveform.The major improvement by this method over the previous one-layer-crust search method is its use of a more realistic multi-layer-crust(MLC)velocity model in the study region based on available information.Numerical tests show that compared with the previous search method the MLC search method is faster and more reliable and accurate.One limit of the MLC search method is the requirement of a multi-layer background model,thus this method might not be applicable in regions where the velocity structure is unknown.Nevertheless,our numerical tests show that the MLC search method is robust in the sense that small deviations of the background model from the true velocity model do not influence the results severely.We applied the MLC search method to data from a temporary linear array across the Wabash Valley Seismic Zone in the central USA.We obtained 157 PmP travel-time measurements that show lateral crustal structure variation in the region.The measurements provide additional constraints in joint inversion for crustal velocity structure in this seismically active region.
基金Supported by National Natural Science Foundation of China(U1604110,U1404319,31600992,31801332)Key Project of Science and Technology in Henan Province(182102110442,152102110036)+6 种基金Nanhu Scholars Program for Young Scholars of XYNU(2016054)Scientific Research Innovation Project for Postgraduate of XYNU(2018KYJJ47)Major Science and Technology Project in Henan Province(121100110200)National Innovation and Entrepreneurship Training Program for Undergraduates(201810477004)Student Research Fund Project of XYNU(2018-DXS-066)Key Scientific Research Projects of Universities in Henan Province(19A180030)Institute for Conservation and Utilization of Agro-bioresources in Dabie Mountains
文摘Amino acid transporters( AATs) play an important role in transport process of various amino acids,which are indispensable in plant growth and development,while many putative AATs have been identified and the complete genomic sequences of the important plants have already been completed by splicing and assembling. There is still little knowledge about the expression,regulation and various biological functions of AATs in plants,including the major food crops. This study mainly reviewed the expression,regulation and various biological functions of AATs in plants,and the application of AATs in crop genetic improvement was also prospected. Thus,this review will provide important information for genetic improvement of staple food crops in plants.
基金Supported by National Natural Science Foundation of China(U1604110,U1404319,31600992,31801332)Key Project of Science and Technology in Henan Province(182102110442,152102110100,152102110036)+6 种基金Nanhu Scholars Program for Young Scholars of XYNU(2016054)Scientific Research Innovation Project for Postgraduate of XYNU(2018KYJJ47)Major Science and Technology Project in Henan Province(121100110200)Student Research Fund Project of XYNU(2018-DXS-066)National Innovation and Entrepreneurship Training Program for Undergraduates(201810477004)Key Scientific Research Projects of Universities in Henan Province(19A180030)Institute for Conservation and Utilization of Agro-bioresources in Dabie Mountains
文摘Starch and the storage proteins are the main nutritious substances in crop grains,and their composition and content in grains play a decisive role in the grain quality of rice and other staple food crops.This review has mainly summarized the new advances in the expression regulation of starch and storage protein synthesis related genes in rice grains.Moreover,the challenges of the starch and storage protein synthesis substances in rice genetic improvement were also discussed.This review will provide important information for genetic improvement of grain quality in rice and,potentially,other staple cereals.
基金the National Natural Science Foundation of China(No.32270835 to DC)the Zhejiang Natural Science Foundation(No.Z22C129553 to DC).
文摘As the most prevalent and reversible internal epigenetic modification in eukaryotic mRNAs,N6-methyladenosine(m^(6)A)post-transcriptionally regulates the processing and metabolism of mRNAs involved in diverse biological processes.m^(6)A modification is regulated by m^(6)A writers,erasers,and readers.Emerging evidence suggests that m^(6)A modification plays essential roles in modulating the cell-fate transition of embryonic stem cells.Mechanistic investigation of embryonic stem cell maintenance and differentiation is critical for understanding early embryonic development,which is also the premise for the application of embryonic stem cells in regenerative medicine.This review highlights the current knowledge of m^(6)A modification and its essential regulatory contribution to the cell fate transition of mouse and human embryonic stem cells.
基金financially supported by the National Science Fund for Distinguished Young Scholars(No.82225027)the National Key Research and Development Program(No.2021YFA1101301)+1 种基金the National Natural Science Foundation of China(Nos.82271419,82202702,82202351,82001308,and 82271418)Shanghai Rising-Star Program(No.22QA1408200).
文摘Stem cell-derived spinal cord organoids(SCOs)have revolutionised the study of spinal cord development and disease mechanisms,offering a three-dimensional model that recapitulates the complexity of native tissue.This review synthesises recent advancements in SCO technology,highlighting their role in modelling spinal cord morphogenesis and their application in neurodegenerative disease research.We discuss the methodological breakthroughs in inducing regional specification and cellular diversity within SCOs,which have enhanced their predictive ability for drug screening and their relevance in mimicking pathological conditions such as neurodegenerative diseases and neuromuscular disorders.Despite these strides,challenges in achieving vascularisation and mature neuronal integration persist.The future of SCOs lies in addressing these limitations,potentially leading to transformative impactions in regenerative medicine and therapeutic development.
