Long-term mulching has improved crop yields and farmland productivity in semiarid areas,but it has also increased greenhouse gas(GHG)emissions and depleted soil fertility.Biochar application has emerged as a promising...Long-term mulching has improved crop yields and farmland productivity in semiarid areas,but it has also increased greenhouse gas(GHG)emissions and depleted soil fertility.Biochar application has emerged as a promising solution for addressing these issues.In this study,we investigated the effects of four biochar application rates(no biochar(N)=0 t ha^(-1),low(L)=3 t ha^(-1),medium(M)=6 t ha^(-1),and high(H)=9 t ha^(-1))under film mulching and no mulching conditions over three growing seasons.We assessed the impacts on GHG emissions,soil organic carbon sequestration(SOCS),and maize yield to evaluate the productivity and sustainability of farmland ecosystems.Our results demonstrated that mulching increased maize yield(18.68-41.80%),total fixed C in straw(23.64%),grain(28.87%),and root(46.31%)biomass,and GHG emissions(CO_(2),10.78%;N_(2)O,3.41%),while reducing SOCS(6.57%)and GHG intensity(GHGI;13.61%).Under mulching,biochar application significantly increased maize yield(10.20%),total fixed C in straw(17.97%),grain(17.69%)and root(16.75%)biomass,and SOCS(4.78%).Moreover,it reduced the GHG emissions(CO_(2),3.09%;N_(2)O,6.36%)and GHGI(12.28%).These effects correlated with the biochar addition rate,with the optimal rate being 9.0 t ha^(-1).In conclusion,biochar application reduces CO_(2) and N_(2)O emissions,enhances CH_(4) absorption,and improves maize yield under film mulching.It also improves the soil carbon fixation capacity while mitigating the warming potential,making it a promising sustainable management method for mulched farmland in semiarid areas.展开更多
Si,as the most promising anode with high theoretical capacity for next-generation lithium-ion batteries(LIBs),is hampered in commercial application by its poor electrical conductivity and significant volume expansion....Si,as the most promising anode with high theoretical capacity for next-generation lithium-ion batteries(LIBs),is hampered in commercial application by its poor electrical conductivity and significant volume expansion.Herein,the core-shell Si@SiO_(x)/C@C-Ar(SSC-A)or Si@SiO_(x)/C@C-H_(2)/Ar(SSC-H)composites are purposefully designed by in situ introduction of inorganic SiO_(x)in pure Ar or H_(2)/Ar atmosphere to realize a Si-based anode for LIBs.By introducing different atmospheres,the valence states of SiO_(x)are regulated.The inorganic transition layer formed by the combination of SiO_(x)with higher average valence and asphalt-derived carbon demonstrates better performance in both stabilizing the core-shell structure and inhibiting the agglomeration of Si particles.Given these advantages,the SSC-A electrode exhibits excellent electrochemical performance(1163 mAh g^(-1)after 400 cycles at 1 A g^(-1)),and the commercial blended graphite-SSC-A electrode reaches a specific capacity of 442 mAh g^(-1)with 74.8%capacity retention under the same conditions.Even the SSC-A electrode without Super P maintains an ultrahigh discharge specific capacity of 803 mAh g^(-1)with 60.6%after cycling.Importantly,the full batteries based on SSC-A without Super P achieve a discharge specific capacity of 126 mAh g^(-1)with 28.2%capacity decay after 200 cycles,demonstrating the superior commercial application potential.展开更多
The dynamic stall problem for blades is related to the general performance of wind turbines,where a varying flow field is introduced with a rapid change of the effective angle of attack (AOA).The objective of this wor...The dynamic stall problem for blades is related to the general performance of wind turbines,where a varying flow field is introduced with a rapid change of the effective angle of attack (AOA).The objective of this work is to study the aerodynamic performance of a sinusoidally oscillating NACA0012 airfoil.The coupled k-ω Menter's shear stress transport (SST) turbulence model and γ-Reθ transition model were used for turbulence closure.Lagrangian coherent structures (LCS) were utilized to analyze the dynamic behavior of the flow structures.The computational results were supported by the experiments.The results indicated that this numerical method can well describe the dynamic stall process.For the case with reduced frequency K =0.1,the lift and drag coefficients increase constantly with increasing angle prior to dynamic stall.When the AOA reaches the stall angle,the lift and drag coefficients decline suddenly due to the interplay between the first leading-and trailing-edge vortex.With further increase of the AOA,both the lift and drag coefficients experience a secondary rise and fall process because of formation and shedding of the secondary vortex.The results also reveal that the dynamic behavior of the flow structures can be effectively identified using the finite-time Lyapunov exponent (FTLE) field.The influence of the reduced frequency on the flow structures and energy extraction efficiency in the dynamic stall process is further discussed.When the reduced frequency increases,the dynamic stall is delayed and the total energy extraction efficiency is enhanced.With K =0.05,the amplitude of the dynamic coefficients fluctuates more significantly in the poststall process than in the case of K =0.1.展开更多
At present,frequent outbreaks of bacteria and viruses have seriously affected people's normal lives.Therefore,the study of broad-spectrum antibacterial nanocomposites is very promising.However,most antibacterial m...At present,frequent outbreaks of bacteria and viruses have seriously affected people's normal lives.Therefore,the study of broad-spectrum antibacterial nanocomposites is very promising.However,most antibacterial materials have some disadvantages,such as single bactericidal mechanisms and unrepeatable use.Based on the current situation,a kind of nanocomposite with three structures of graphene oxide(GO),quaternary ammonium salt(QAs)and N-halamine was prepared,which showed synergistic effect to improve antibacterial activity and combined with a variety of sterilization mechanisms.Meanwhile,GO can provide richer ways of sterilization and high specific surface area,which is conducive to the grafting of quaternarized N-halamine.The advantages of physical sterilization of GO,charge adsorption of QAs,reuse of N-halamine and efficient sterilization are fully utilized.The results showed that the quaternarized N-halamine-grafted GO was obtained successfully.GO grafted with quaternarized N-halamine polymer showed strong speedy bactericidal activity against Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)(99%).It had good storage and regeneration properties.展开更多
Particles administrated intravenously will pass through the pulmonary capillary network before being distributed to the body.Therefore,fabrication of vectors sensitive to blood shear and active with blood components s...Particles administrated intravenously will pass through the pulmonary capillary network before being distributed to the body.Therefore,fabrication of vectors sensitive to blood shear and active with blood components should be a practical approach to develop lung-targe ting gene carriers self-regulated by circulatory system.In this work,we designed a series of cationic peptides with the same charge density but varying hydrophobicity and capacity to form hydrogen bonds,and investigated their ability to form co mplexes with siRNA,the behaviours of peptide/siRNA complexes in the presence of serum under shear,and the lung-targeting efficacy of the complexes regulated by blood.The hydrophobic interaction co ntrols the complexation between peptide and siRNA,while the hydrogen bonds are responsible for the binding of peptides to the serum components in blood.In vivo tests show that all the peptide/siRNA complexes can accumulate in lung.However,only the complexes that exhibit weak interaction with serum components and can be broken down by shear avoid the inflammation and death caused by pulmonary embolism.Moreover,the peptide with strong hydrophobicity can retain siRNA in lung without early release of the cargo.Our study provides a step toward the development of adaptive gene carriers under the regulation of circulatory system.展开更多
Variable camber wing technology is one of the important development trends of green aviation at present.Through smooth,seamless,continuous and adaptive change of wing camber,the aerodynamic performance is improved in ...Variable camber wing technology is one of the important development trends of green aviation at present.Through smooth,seamless,continuous and adaptive change of wing camber,the aerodynamic performance is improved in achieving increase in lift and reduction in resistance and noise.Based on the aerodynamic validation model CAE-AVM,Chinese Aeronautical Establishment(CAE)has carried out the design and validation of a variable camber wing,proposed an aerodynamic deformation matrix for the leading and trailing edges of aircraft wings in takeoff,landing and cruise conditions.Various structures and driving schemes are compared,and several key technology problems of leading and trailing edge deformation are solved.A full-size leading edge wind tunnel test piece with a span of 2.7 m and a trailing edge ground function test piece are developed.The deformation and shape maintenance capabilities of the leading edge is verified under real wind load conditions,and the load bearing and deformation capabilities of the trailing edge is verified under simulated follow-on load.The results indicate that the leading and trailing edges of the variable camber wing can achieve the required deformation angle and have a certain load-bearing capacity.Our study can provide some insights into the application of variable camber wing technology for civil aircraft.展开更多
Cancer stem cell-like cells(CSCs)play an integral role in the heterogeneity,metastasis,and treatment resistance of head and neck squamous cell carcinoma(HNSCC)due to their high tumor initiation capacity and plasticity...Cancer stem cell-like cells(CSCs)play an integral role in the heterogeneity,metastasis,and treatment resistance of head and neck squamous cell carcinoma(HNSCC)due to their high tumor initiation capacity and plasticity.Here,we identified a candidate gene named LIMP-2 as a novel therapeutic target regulating HNSCC progression and CSC properties.The high expression of LIMP-2 in HNSCC patients suggested a poor prognosis and potential immunotherapy resistance.展开更多
Despite the promising prospect of small interfering RNA(siRNA)for the treatment of diverse diseases,it remains challenging to develop novel delive ry materials to desired tissues and cells.In this study,a novel iron o...Despite the promising prospect of small interfering RNA(siRNA)for the treatment of diverse diseases,it remains challenging to develop novel delive ry materials to desired tissues and cells.In this study,a novel iron oxyhydroxide(FeOOH)nanoparticle(NP)whose surface was modified with branched polyetherimide(PEI)was developed to deliver siRNA into the cancer cells.It was demonstrated that PEI-FeOOH(PFeOOH)efficiently complexed siRNA,mediated effective cellular uptake and endosomal escape,thereby triggering robust gene silencing in vitro.In addition,PFeOOH/siRNA formulation loading with anti-RRM2 siRNA effectively inhibited the growth of tumor tissues,and exhibited excellent safety profiles in vivo.Therefore,this study conceptually provided a FeOOH-based nucleic acid delivery vesicle which can potentially use to achieve diagnosis and therapy simultaneously.展开更多
To explore and enrich the molecular mechanisms of thyroid hormone receptors （TRs） in the metamorphosis of amphibians, the cDNA sequences of TRa and TRβ in Microhyla fissipes were cloned and characterized. TRa was 1...To explore and enrich the molecular mechanisms of thyroid hormone receptors （TRs） in the metamorphosis of amphibians, the cDNA sequences of TRa and TRβ in Microhyla fissipes were cloned and characterized. TRa was 1 706 bp in length with an open reading frame （ORF） of 1 257 bp encoding a predicted protein of 418 amino acids and TRβ was 1 422 bp with an ORF of 1 122 bp encoding a predicted protein of 373 amino acids. Their protein sequences contained 4 conserved domains of the nuclear receptor superfamily with two highly conserved cysteine-rich zinc fingers in the DNA-binding domain, whereas TRβ was 42 amino acids shorter in its A/B domain than TRot. Highly-conserved sequences and structures indicated their conserved functions during metamorphosis. TRa expression reached peak at 12 h and then decreased from 12 h to 48 h. While dramatically up-regulated TRβ was observed after exposure of T3 within 24 h, and it was down-regulated from 24 h to 48 h. The expression pattern of TRβ is similar to that in the natural metamorphosis. Furthermore, tadpoles treated 24 h also resembled the climax of metamorphosis tadpoles and TRβ expression had higher responsiveness than TRa to T3 in M. fissipes. These results suggest M. fissipes may serve as the model to assay environmental compounds on TH signaling disruption.展开更多
The objective of this paper is to investigate the hysteresis effect of cavitating flow over a Clark-Y hydrofoil undergoing a transient pitching motion at Reynolds number Re=4.55×105,cavitation numberσ=1.33,pitch...The objective of this paper is to investigate the hysteresis effect of cavitating flow over a Clark-Y hydrofoil undergoing a transient pitching motion at Reynolds number Re=4.55×105,cavitation numberσ=1.33,pitching frequency f*=2 Hz via combined experimental and numerical studies.A hysteresis phenomenon is observed in the hydrodynamic curve and cavity area in increasing and decreasing of the angle of attackα.The hydrodynamic curves are divided into three regions:Regions A,B and C.For Region A,the lift coefficient of downstroke is lower than that of the upstroke,and the lift coefficient curve of the downstroke is more unstable.The formation and development of counterclockwise trailing edge vortex(TEV)are responsible for the decline and fluctuation of lift during the downstroke,thus leading to the increase of the hysteresis loop.Compared with the upstroke,the hydrodynamic curve in downstroke is shifted laterally to some extent in Region B.The delay effect is the main factor leading to the shift of the hydrodynamic curve,which corresponds to the minimum hysteresis loop.In Region C,the hysteresis loop is maximum and the evolution trend of the hydrodynamic curve is peak-valley opposites.When the direction of oscillation changes,the detachment and dwell time of the cavity are advanced,thus leading to the difference of hydrodynamic curve and the increase of hysteresis loop.展开更多
Based on the night light data, urban area data, and economic data of Wuhan Urban Agglomeration from 2009 to 2015, we use spatial correlation dimension, spatial self-correlation analysis and weighted standard deviation...Based on the night light data, urban area data, and economic data of Wuhan Urban Agglomeration from 2009 to 2015, we use spatial correlation dimension, spatial self-correlation analysis and weighted standard deviation ellipse to identify the general characteristics and dynamic evolution characteristics of urban spatial pattern and economic disparity pattern. The research results prove that: between 2009 and 2013, Wuhan Urban Agglomeration expanded gradually from northwest to southeast and presented the dynamic evolution features of “along the river and the road”. The spatial structure is obvious, forming the pattern of “core-periphery”. The development of Wuhan Urban Agglomeration has obvious imbalance in economic geography space, presenting the development tendency of “One prominent, stronger in the west and weaker in the east”. The contract within Wuhan Urban Agglomeration is gradually decreased. Wuhan city and its surrounding areas have stronger economic growth strength as well as the cities along The Yangtze River. However, the relative development rate of Wuhan city area is still far higher than other cities and counties.展开更多
This paper sets Chaihu Town, Zhongxiang City of Hubei Province as an example, analyzing the ecological and hydrological conditions of Chaihu Town, applying LID （low impact development） mode and putting forward the e...This paper sets Chaihu Town, Zhongxiang City of Hubei Province as an example, analyzing the ecological and hydrological conditions of Chaihu Town, applying LID （low impact development） mode and putting forward the ecological stormwater regulation system planning strategy which adapts to the development of small towns. The main conclusions are as follows： （1） The ＂three-low＂ development mode is put forward, which means low impact, low cost and low carbon, using this construction mode to minimize the ecological impact, relying on natural green space and water to achieve the function of rainstorm regulation; （2） Through the analysis and calculation of the local amount of precipitation, this paper scientifically calculates the required area of storage water and green space, taking the roads as trunks, green spaces as stems, water as veins, and building the green infrastructure system; （3） The author has been repairing and integrating the original drainage ditches of the planning area, replacing traditional rain drainage pipes, establishing ＂two-loop＂ water network system which aims at the detention and purification of rainwater, maximizing ecological benefit, economic benefit and landscape benefit.展开更多
Dermatologists typically require extensive experience to accurately classify skin cancer.In recent years,the development of computer vision and machine learning has provided new methods for assisted diagnosis.Existing...Dermatologists typically require extensive experience to accurately classify skin cancer.In recent years,the development of computer vision and machine learning has provided new methods for assisted diagnosis.Existing skin cancer image classification methods have certain limitations,such as poor interpretability,the requirement of domain knowledge for feature extraction,and the neglect of lesion area information in skin images.This paper proposes a new genetic programming(GP)approach to automatically learn global and/or local features from skin images for classification.To achieve this,a new function set and a new terminal set have been developed.The proposed GP method can automatically and flexibly extract effective local/global features from different types of input images,thus providing a comprehensive description of skin images.A new region detection function has been developed to select the lesion areas from skin images for feature extraction.The performance of this approach is evaluated on three skin cancer image classification tasks,and compared with three GP methods and six non-GP methods.The experimental results show that the new approach achieves significantly better or similar performance in most cases.Further analysis validates the effectiveness of our parameter settings,visualizes the multiple region detection functions used in the individual evolved by the proposed approach,and demonstrates its good convergence ability.展开更多
Introduction:Tetanus remains a significant public health concern in China,with a notable proportion of injured patients declining tetanus vaccination.This study aims to investigate the prevalence and determinants of t...Introduction:Tetanus remains a significant public health concern in China,with a notable proportion of injured patients declining tetanus vaccination.This study aims to investigate the prevalence and determinants of tetanus vaccine hesitancy and identify effective strategies to address this critical public health challenge.Methods:We calculated tetanus vaccine hesitancy rates among trauma patients presenting at eight hospitals across China from April 1 to June 30,2024.A comprehensive questionnaire survey was conducted from June 3 to June 27,2024,targeting patients aged 11 years and older who had open wounds requiring tetanus immunization but refused vaccination.The survey assessed participants’sociodemographic characteristics,knowledge,attitudes,and practices regarding tetanus and tetanus vaccines.Statistical analyses included Pearson’s Chi-squared tests,multiple response analyses,and goodness of fit tests.Results:Among 8,993 trauma patients requiring tetanus vaccination,26.78%declined immunization.Analysis of 503 consecutively collected questionnaires revealed low overall awareness of tetanus and tetanus vaccines,with only 20.1%of respondents demonstrating comprehensive knowledge of tetanusrelated questions.The predominant reason for vaccine hesitancy(34.5%)was the perception that post-injury tetanus risk was minimal.Across all age groups,medical institutions and healthcare professionals were consistently identified as the most effective sources for tetanus prevention information.Conclusion:This study demonstrates that enhancing public awareness about tetanus and its vaccines while addressing complacency are fundamental to reducing vaccine hesitancy.Targeted educational interventions delivered by healthcare institutions and professionals can significantly improve public knowledge and acceptance of tetanus vaccination.展开更多
Small interfering RNA(siRNA)has shown promising therapeutic prospects in many major diseases.However,two main reasons limit the application of siRNA:poor endocytosis efficiency and weak endosomal escape ability.Theref...Small interfering RNA(siRNA)has shown promising therapeutic prospects in many major diseases.However,two main reasons limit the application of siRNA:poor endocytosis efficiency and weak endosomal escape ability.Therefore,the development of efficient and safe delivery vectors has always been an important study aspect of RNAi technology.Herein,we designed a self-assembled nanoparticle based on functionalized peptides to deliver siRNA to the down-regulated polo-like kinase 1(PLK1)gene,which can inhibit tumor cells in the G2 phase.The functional polypeptide consists of cell membrane-penetrating peptide(CPP44)and p16 minimal inhibitory sequence(p16MIS).CPP44 can effectively mediate endocytosis,while p16MIS can inhibit tumor growth in the G1 phase and synergistically promote the apoptosis of tumor cells with siPLK1.In vitro and in vivo studies demonstrate that the developed nanoparticle exhibits high levels of silencing efficiency,antitumor activity,and therapeutic efficacy.Consequently,this study provides a novel approach to cancer treatment by simultaneously disrupting two stages of tumor cell division.展开更多
As the earliest geographical unit of human activities,river basins have nurtured civilizations with distinct local cha racteristics.The"human-water relationship"is a key aspect of"human-environment inte...As the earliest geographical unit of human activities,river basins have nurtured civilizations with distinct local cha racteristics.The"human-water relationship"is a key aspect of"human-environment interaction,"driving the evolution of urban and rural systems through human adaptation to water.Using Yichang as a case,this paper analyzes population and land use changes to explore the evolution of its"mountain-water-city"spatial patte rn.Yichang grows incrementally along the river,forming a compact multi-cluster layout.At the same time,influenced by the significant and special event of the Three Gorges Project construction,the city has undergone rapid"leapfrog"development.Amid population mobility and river basin management needs,Yichang should use its"water"feature to integrate function,scale,and structure,focusing on water protection and utilization to ensure national and energy security.Secondly,amidst the general trend of declining total population and slowing growth,it is necessary to reasonably guide the aggregation and distribution of population within urban spaces based on the resource carrying capacity of each river basin.Finally,Yichang should break linear development inertia,focus on dual city cente rs,and redirect leading industries from rive rs/roads to the eastern industrial city.展开更多
In the cutting-edge realm of contemporary biomedical research,targeted protein degradation(TPD)technology has garnered sig-nificant attention due to its rapid advancement^(1,2).This approach modulates protein levels b...In the cutting-edge realm of contemporary biomedical research,targeted protein degradation(TPD)technology has garnered sig-nificant attention due to its rapid advancement^(1,2).This approach modulates protein levels by harnessing the cell’s intrinsic degra-dation machinery,and shows therapeutic potential for diverse diseases,such as cancer and neurodegenerative disorders.How-ever,TPD tools require laborious case-by-case design tailored to different diseases and cell types when targeting new proteins,particularly for extracellular protein targets.展开更多
基金supported by the National Key Research and Development Program of China(2021YFE0101300 and 2021YFD1901102)the project supported by the Natural Science Basic Research Plan in Shaanxi Province,China(2023-JC-YB-185)the Ningxia Key Research and Development Program,China(2023BCF01018)。
文摘Long-term mulching has improved crop yields and farmland productivity in semiarid areas,but it has also increased greenhouse gas(GHG)emissions and depleted soil fertility.Biochar application has emerged as a promising solution for addressing these issues.In this study,we investigated the effects of four biochar application rates(no biochar(N)=0 t ha^(-1),low(L)=3 t ha^(-1),medium(M)=6 t ha^(-1),and high(H)=9 t ha^(-1))under film mulching and no mulching conditions over three growing seasons.We assessed the impacts on GHG emissions,soil organic carbon sequestration(SOCS),and maize yield to evaluate the productivity and sustainability of farmland ecosystems.Our results demonstrated that mulching increased maize yield(18.68-41.80%),total fixed C in straw(23.64%),grain(28.87%),and root(46.31%)biomass,and GHG emissions(CO_(2),10.78%;N_(2)O,3.41%),while reducing SOCS(6.57%)and GHG intensity(GHGI;13.61%).Under mulching,biochar application significantly increased maize yield(10.20%),total fixed C in straw(17.97%),grain(17.69%)and root(16.75%)biomass,and SOCS(4.78%).Moreover,it reduced the GHG emissions(CO_(2),3.09%;N_(2)O,6.36%)and GHGI(12.28%).These effects correlated with the biochar addition rate,with the optimal rate being 9.0 t ha^(-1).In conclusion,biochar application reduces CO_(2) and N_(2)O emissions,enhances CH_(4) absorption,and improves maize yield under film mulching.It also improves the soil carbon fixation capacity while mitigating the warming potential,making it a promising sustainable management method for mulched farmland in semiarid areas.
基金financially supported by the National Natural Science Foundation of China(Nos.U22A20145,52072151,52171211,and 52271218)Jinan Independent Innovative Team(No.2020GXRC015)+3 种基金the Major Program of Shandong Province Natural Science Foundation(No.ZR2023ZD43)Natural Science Foumdation of Jiangsu Province(No.BK20241973)High-level Training Talents of'333'Project in Jiangsu Provincethe Science and Technology Program of University of Jinan(No.XKY2119)
文摘Si,as the most promising anode with high theoretical capacity for next-generation lithium-ion batteries(LIBs),is hampered in commercial application by its poor electrical conductivity and significant volume expansion.Herein,the core-shell Si@SiO_(x)/C@C-Ar(SSC-A)or Si@SiO_(x)/C@C-H_(2)/Ar(SSC-H)composites are purposefully designed by in situ introduction of inorganic SiO_(x)in pure Ar or H_(2)/Ar atmosphere to realize a Si-based anode for LIBs.By introducing different atmospheres,the valence states of SiO_(x)are regulated.The inorganic transition layer formed by the combination of SiO_(x)with higher average valence and asphalt-derived carbon demonstrates better performance in both stabilizing the core-shell structure and inhibiting the agglomeration of Si particles.Given these advantages,the SSC-A electrode exhibits excellent electrochemical performance(1163 mAh g^(-1)after 400 cycles at 1 A g^(-1)),and the commercial blended graphite-SSC-A electrode reaches a specific capacity of 442 mAh g^(-1)with 74.8%capacity retention under the same conditions.Even the SSC-A electrode without Super P maintains an ultrahigh discharge specific capacity of 803 mAh g^(-1)with 60.6%after cycling.Importantly,the full batteries based on SSC-A without Super P achieve a discharge specific capacity of 126 mAh g^(-1)with 28.2%capacity decay after 200 cycles,demonstrating the superior commercial application potential.
基金the National Postdoctoral Program for Innovative Talents(Grant BX201700126)the China Postdoctoral Science Foundation(Grant 2017M620043)+1 种基金the National Natural Science Foundation of China(Grants 51679005 and 91752105)the National Natural Science Foundation of Beijing(Grant 3172029).
文摘The dynamic stall problem for blades is related to the general performance of wind turbines,where a varying flow field is introduced with a rapid change of the effective angle of attack (AOA).The objective of this work is to study the aerodynamic performance of a sinusoidally oscillating NACA0012 airfoil.The coupled k-ω Menter's shear stress transport (SST) turbulence model and γ-Reθ transition model were used for turbulence closure.Lagrangian coherent structures (LCS) were utilized to analyze the dynamic behavior of the flow structures.The computational results were supported by the experiments.The results indicated that this numerical method can well describe the dynamic stall process.For the case with reduced frequency K =0.1,the lift and drag coefficients increase constantly with increasing angle prior to dynamic stall.When the AOA reaches the stall angle,the lift and drag coefficients decline suddenly due to the interplay between the first leading-and trailing-edge vortex.With further increase of the AOA,both the lift and drag coefficients experience a secondary rise and fall process because of formation and shedding of the secondary vortex.The results also reveal that the dynamic behavior of the flow structures can be effectively identified using the finite-time Lyapunov exponent (FTLE) field.The influence of the reduced frequency on the flow structures and energy extraction efficiency in the dynamic stall process is further discussed.When the reduced frequency increases,the dynamic stall is delayed and the total energy extraction efficiency is enhanced.With K =0.05,the amplitude of the dynamic coefficients fluctuates more significantly in the poststall process than in the case of K =0.1.
基金supported by the National Natural Science Foundation of China(No.51603020)the Jilin Province Science and Technology Natural Science Foundation Project of China(No.20180101193JC).
文摘At present,frequent outbreaks of bacteria and viruses have seriously affected people's normal lives.Therefore,the study of broad-spectrum antibacterial nanocomposites is very promising.However,most antibacterial materials have some disadvantages,such as single bactericidal mechanisms and unrepeatable use.Based on the current situation,a kind of nanocomposite with three structures of graphene oxide(GO),quaternary ammonium salt(QAs)and N-halamine was prepared,which showed synergistic effect to improve antibacterial activity and combined with a variety of sterilization mechanisms.Meanwhile,GO can provide richer ways of sterilization and high specific surface area,which is conducive to the grafting of quaternarized N-halamine.The advantages of physical sterilization of GO,charge adsorption of QAs,reuse of N-halamine and efficient sterilization are fully utilized.The results showed that the quaternarized N-halamine-grafted GO was obtained successfully.GO grafted with quaternarized N-halamine polymer showed strong speedy bactericidal activity against Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)(99%).It had good storage and regeneration properties.
基金This work was supported by Beijing Natural Science Foundation(No.2171001)the National Natural Science Foundation of China(Nos.21973002,21774002,31871003,31901053)+2 种基金the Beijing-Tianjin-Hebei Basic Research Cooperation Project(No.19JCZDJC64100)the Beijing Nova Program from Beijing Municipal Science&Technology Commission(No.Z201100006820005)the Young Elite Scientist Sponsorship Program of Beijing Association for Science and Technology(No.2020-2022)。
文摘Particles administrated intravenously will pass through the pulmonary capillary network before being distributed to the body.Therefore,fabrication of vectors sensitive to blood shear and active with blood components should be a practical approach to develop lung-targe ting gene carriers self-regulated by circulatory system.In this work,we designed a series of cationic peptides with the same charge density but varying hydrophobicity and capacity to form hydrogen bonds,and investigated their ability to form co mplexes with siRNA,the behaviours of peptide/siRNA complexes in the presence of serum under shear,and the lung-targeting efficacy of the complexes regulated by blood.The hydrophobic interaction co ntrols the complexation between peptide and siRNA,while the hydrogen bonds are responsible for the binding of peptides to the serum components in blood.In vivo tests show that all the peptide/siRNA complexes can accumulate in lung.However,only the complexes that exhibit weak interaction with serum components and can be broken down by shear avoid the inflammation and death caused by pulmonary embolism.Moreover,the peptide with strong hydrophobicity can retain siRNA in lung without early release of the cargo.Our study provides a step toward the development of adaptive gene carriers under the regulation of circulatory system.
基金supported by the National Research Project“Variable Camber Wing Technology(VCAN)”,China。
文摘Variable camber wing technology is one of the important development trends of green aviation at present.Through smooth,seamless,continuous and adaptive change of wing camber,the aerodynamic performance is improved in achieving increase in lift and reduction in resistance and noise.Based on the aerodynamic validation model CAE-AVM,Chinese Aeronautical Establishment(CAE)has carried out the design and validation of a variable camber wing,proposed an aerodynamic deformation matrix for the leading and trailing edges of aircraft wings in takeoff,landing and cruise conditions.Various structures and driving schemes are compared,and several key technology problems of leading and trailing edge deformation are solved.A full-size leading edge wind tunnel test piece with a span of 2.7 m and a trailing edge ground function test piece are developed.The deformation and shape maintenance capabilities of the leading edge is verified under real wind load conditions,and the load bearing and deformation capabilities of the trailing edge is verified under simulated follow-on load.The results indicate that the leading and trailing edges of the variable camber wing can achieve the required deformation angle and have a certain load-bearing capacity.Our study can provide some insights into the application of variable camber wing technology for civil aircraft.
基金financially supported by the National Natural Science Foundation of China 82273202,82103670,and 82072996。
文摘Cancer stem cell-like cells(CSCs)play an integral role in the heterogeneity,metastasis,and treatment resistance of head and neck squamous cell carcinoma(HNSCC)due to their high tumor initiation capacity and plasticity.Here,we identified a candidate gene named LIMP-2 as a novel therapeutic target regulating HNSCC progression and CSC properties.The high expression of LIMP-2 in HNSCC patients suggested a poor prognosis and potential immunotherapy resistance.
基金supported by the Hunan Provincial Natural Science Foundation of China(Nos.2018JJ1019,2019JJ50196)the Hu-Xiang Young Talent Program(No.2018RS3094)+4 种基金the National Natural Science Foundation of China(Nos.31871003,31901053)the Beijing Institute of Technology Research Fund Program for Young Scholars and the Fundamental Research Funds for the Central Universities(No.2018CX01023)the Beijing-Tianjin-Hebei Basic Research Cooperation Project(No.19JCZDJC64100)the Beijing Nova Program from Beijing Municipal Science&Technology Commission(No.Z201100006820005)the Young Elite Scientist Sponsorship Program of Beijing Association for Science and Technology(2020-2022)。
文摘Despite the promising prospect of small interfering RNA(siRNA)for the treatment of diverse diseases,it remains challenging to develop novel delive ry materials to desired tissues and cells.In this study,a novel iron oxyhydroxide(FeOOH)nanoparticle(NP)whose surface was modified with branched polyetherimide(PEI)was developed to deliver siRNA into the cancer cells.It was demonstrated that PEI-FeOOH(PFeOOH)efficiently complexed siRNA,mediated effective cellular uptake and endosomal escape,thereby triggering robust gene silencing in vitro.In addition,PFeOOH/siRNA formulation loading with anti-RRM2 siRNA effectively inhibited the growth of tumor tissues,and exhibited excellent safety profiles in vivo.Therefore,this study conceptually provided a FeOOH-based nucleic acid delivery vesicle which can potentially use to achieve diagnosis and therapy simultaneously.
基金funded by the Important Research Project of Chinese Academy of Sciences (KJZG-EW-L13)2015 Western Light Talent Culture Project of the Chinese Academy of Sciences (Y6C3021)the Basic Application Project of Sichuan Province (2017JY0339)
文摘To explore and enrich the molecular mechanisms of thyroid hormone receptors （TRs） in the metamorphosis of amphibians, the cDNA sequences of TRa and TRβ in Microhyla fissipes were cloned and characterized. TRa was 1 706 bp in length with an open reading frame （ORF） of 1 257 bp encoding a predicted protein of 418 amino acids and TRβ was 1 422 bp with an ORF of 1 122 bp encoding a predicted protein of 373 amino acids. Their protein sequences contained 4 conserved domains of the nuclear receptor superfamily with two highly conserved cysteine-rich zinc fingers in the DNA-binding domain, whereas TRβ was 42 amino acids shorter in its A/B domain than TRot. Highly-conserved sequences and structures indicated their conserved functions during metamorphosis. TRa expression reached peak at 12 h and then decreased from 12 h to 48 h. While dramatically up-regulated TRβ was observed after exposure of T3 within 24 h, and it was down-regulated from 24 h to 48 h. The expression pattern of TRβ is similar to that in the natural metamorphosis. Furthermore, tadpoles treated 24 h also resembled the climax of metamorphosis tadpoles and TRβ expression had higher responsiveness than TRa to T3 in M. fissipes. These results suggest M. fissipes may serve as the model to assay environmental compounds on TH signaling disruption.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.52109111,52079004,and U20B2004)the Natural Science Foundation of Beijing(Grant No.3212023)the State Key Program for Basic Research of China(Grant No.MKS20210003).
文摘The objective of this paper is to investigate the hysteresis effect of cavitating flow over a Clark-Y hydrofoil undergoing a transient pitching motion at Reynolds number Re=4.55×105,cavitation numberσ=1.33,pitching frequency f*=2 Hz via combined experimental and numerical studies.A hysteresis phenomenon is observed in the hydrodynamic curve and cavity area in increasing and decreasing of the angle of attackα.The hydrodynamic curves are divided into three regions:Regions A,B and C.For Region A,the lift coefficient of downstroke is lower than that of the upstroke,and the lift coefficient curve of the downstroke is more unstable.The formation and development of counterclockwise trailing edge vortex(TEV)are responsible for the decline and fluctuation of lift during the downstroke,thus leading to the increase of the hysteresis loop.Compared with the upstroke,the hydrodynamic curve in downstroke is shifted laterally to some extent in Region B.The delay effect is the main factor leading to the shift of the hydrodynamic curve,which corresponds to the minimum hysteresis loop.In Region C,the hysteresis loop is maximum and the evolution trend of the hydrodynamic curve is peak-valley opposites.When the direction of oscillation changes,the detachment and dwell time of the cavity are advanced,thus leading to the difference of hydrodynamic curve and the increase of hysteresis loop.
文摘Based on the night light data, urban area data, and economic data of Wuhan Urban Agglomeration from 2009 to 2015, we use spatial correlation dimension, spatial self-correlation analysis and weighted standard deviation ellipse to identify the general characteristics and dynamic evolution characteristics of urban spatial pattern and economic disparity pattern. The research results prove that: between 2009 and 2013, Wuhan Urban Agglomeration expanded gradually from northwest to southeast and presented the dynamic evolution features of “along the river and the road”. The spatial structure is obvious, forming the pattern of “core-periphery”. The development of Wuhan Urban Agglomeration has obvious imbalance in economic geography space, presenting the development tendency of “One prominent, stronger in the west and weaker in the east”. The contract within Wuhan Urban Agglomeration is gradually decreased. Wuhan city and its surrounding areas have stronger economic growth strength as well as the cities along The Yangtze River. However, the relative development rate of Wuhan city area is still far higher than other cities and counties.
文摘This paper sets Chaihu Town, Zhongxiang City of Hubei Province as an example, analyzing the ecological and hydrological conditions of Chaihu Town, applying LID （low impact development） mode and putting forward the ecological stormwater regulation system planning strategy which adapts to the development of small towns. The main conclusions are as follows： （1） The ＂three-low＂ development mode is put forward, which means low impact, low cost and low carbon, using this construction mode to minimize the ecological impact, relying on natural green space and water to achieve the function of rainstorm regulation; （2） Through the analysis and calculation of the local amount of precipitation, this paper scientifically calculates the required area of storage water and green space, taking the roads as trunks, green spaces as stems, water as veins, and building the green infrastructure system; （3） The author has been repairing and integrating the original drainage ditches of the planning area, replacing traditional rain drainage pipes, establishing ＂two-loop＂ water network system which aims at the detention and purification of rainwater, maximizing ecological benefit, economic benefit and landscape benefit.
基金supported in part by National Natural Science Foundation of China(U23A20340,62376253,62106230,62176238,62476254)China Postdoctoral Science Foundation,China(2023M743185)+2 种基金Natural Science Foundation of Henan Province,China(222300420088)Key Laboratory of Big Data Intelligent Computing,Chongqing University of Posts and Telecommunications,China Open Foundation(BDIC-2023-A-007)Frontier Exploration Projects of Longmen Laboratory,China(NO.LMQYTSKT031).
文摘Dermatologists typically require extensive experience to accurately classify skin cancer.In recent years,the development of computer vision and machine learning has provided new methods for assisted diagnosis.Existing skin cancer image classification methods have certain limitations,such as poor interpretability,the requirement of domain knowledge for feature extraction,and the neglect of lesion area information in skin images.This paper proposes a new genetic programming(GP)approach to automatically learn global and/or local features from skin images for classification.To achieve this,a new function set and a new terminal set have been developed.The proposed GP method can automatically and flexibly extract effective local/global features from different types of input images,thus providing a comprehensive description of skin images.A new region detection function has been developed to select the lesion areas from skin images for feature extraction.The performance of this approach is evaluated on three skin cancer image classification tasks,and compared with three GP methods and six non-GP methods.The experimental results show that the new approach achieves significantly better or similar performance in most cases.Further analysis validates the effectiveness of our parameter settings,visualizes the multiple region detection functions used in the individual evolved by the proposed approach,and demonstrates its good convergence ability.
基金Supported by the National High Level Hospital Clinical Research Funding(Interdepartmental Research Project of Peking University First Hospital:2024IR10).
文摘Introduction:Tetanus remains a significant public health concern in China,with a notable proportion of injured patients declining tetanus vaccination.This study aims to investigate the prevalence and determinants of tetanus vaccine hesitancy and identify effective strategies to address this critical public health challenge.Methods:We calculated tetanus vaccine hesitancy rates among trauma patients presenting at eight hospitals across China from April 1 to June 30,2024.A comprehensive questionnaire survey was conducted from June 3 to June 27,2024,targeting patients aged 11 years and older who had open wounds requiring tetanus immunization but refused vaccination.The survey assessed participants’sociodemographic characteristics,knowledge,attitudes,and practices regarding tetanus and tetanus vaccines.Statistical analyses included Pearson’s Chi-squared tests,multiple response analyses,and goodness of fit tests.Results:Among 8,993 trauma patients requiring tetanus vaccination,26.78%declined immunization.Analysis of 503 consecutively collected questionnaires revealed low overall awareness of tetanus and tetanus vaccines,with only 20.1%of respondents demonstrating comprehensive knowledge of tetanusrelated questions.The predominant reason for vaccine hesitancy(34.5%)was the perception that post-injury tetanus risk was minimal.Across all age groups,medical institutions and healthcare professionals were consistently identified as the most effective sources for tetanus prevention information.Conclusion:This study demonstrates that enhancing public awareness about tetanus and its vaccines while addressing complacency are fundamental to reducing vaccine hesitancy.Targeted educational interventions delivered by healthcare institutions and professionals can significantly improve public knowledge and acceptance of tetanus vaccination.
基金supported by the National Natural Science Founda-tion of China(32101148,32171394,82102204)Beijing Nova Program(Interdisciplinary Cooperation Project)from Beijing Municipal Science&Technology Commission(20220484207)+3 种基金National Key Research&Development Program of China(2021YFA1201000,2021YFE0106900,2023YFC2605003)National Natural Science Foundation of China(NSFC)key project(32030060)NSFC international collaboration key project(51861135103)the Science Fund for Creative Research Groups of Nature Science Foundation of Hebei Province(B2021201038).
文摘Small interfering RNA(siRNA)has shown promising therapeutic prospects in many major diseases.However,two main reasons limit the application of siRNA:poor endocytosis efficiency and weak endosomal escape ability.Therefore,the development of efficient and safe delivery vectors has always been an important study aspect of RNAi technology.Herein,we designed a self-assembled nanoparticle based on functionalized peptides to deliver siRNA to the down-regulated polo-like kinase 1(PLK1)gene,which can inhibit tumor cells in the G2 phase.The functional polypeptide consists of cell membrane-penetrating peptide(CPP44)and p16 minimal inhibitory sequence(p16MIS).CPP44 can effectively mediate endocytosis,while p16MIS can inhibit tumor growth in the G1 phase and synergistically promote the apoptosis of tumor cells with siPLK1.In vitro and in vivo studies demonstrate that the developed nanoparticle exhibits high levels of silencing efficiency,antitumor activity,and therapeutic efficacy.Consequently,this study provides a novel approach to cancer treatment by simultaneously disrupting two stages of tumor cell division.
基金funded by the grants from the Ministry of Education Research of Social Sciences Youth funded projects(No.23YJCZH296)the National Natural Science Foundation of China(No.52378057)。
文摘As the earliest geographical unit of human activities,river basins have nurtured civilizations with distinct local cha racteristics.The"human-water relationship"is a key aspect of"human-environment interaction,"driving the evolution of urban and rural systems through human adaptation to water.Using Yichang as a case,this paper analyzes population and land use changes to explore the evolution of its"mountain-water-city"spatial patte rn.Yichang grows incrementally along the river,forming a compact multi-cluster layout.At the same time,influenced by the significant and special event of the Three Gorges Project construction,the city has undergone rapid"leapfrog"development.Amid population mobility and river basin management needs,Yichang should use its"water"feature to integrate function,scale,and structure,focusing on water protection and utilization to ensure national and energy security.Secondly,amidst the general trend of declining total population and slowing growth,it is necessary to reasonably guide the aggregation and distribution of population within urban spaces based on the resource carrying capacity of each river basin.Finally,Yichang should break linear development inertia,focus on dual city cente rs,and redirect leading industries from rive rs/roads to the eastern industrial city.
基金support from the National Natural Science Foundation of China(32171394 and U23A20489)the Funda-mental Research Funds for the Central Universities of China(2022CX01013)the China Postdoctoral Science Foundation(2023M740259,2024M761233).
文摘In the cutting-edge realm of contemporary biomedical research,targeted protein degradation(TPD)technology has garnered sig-nificant attention due to its rapid advancement^(1,2).This approach modulates protein levels by harnessing the cell’s intrinsic degra-dation machinery,and shows therapeutic potential for diverse diseases,such as cancer and neurodegenerative disorders.How-ever,TPD tools require laborious case-by-case design tailored to different diseases and cell types when targeting new proteins,particularly for extracellular protein targets.
