The ground-based experimental tests are crucial to verify the related technologies of the drag-free satellite.This work presents a design method of the ground simulator testbed for emulating the planar dynamics of the...The ground-based experimental tests are crucial to verify the related technologies of the drag-free satellite.This work presents a design method of the ground simulator testbed for emulating the planar dynamics of the space drag-free systems.In this paper,the planar dynamic characteristics of the drag-free satellite with double test masses are analyzed and nondimensionalized.A simulator vehicle composed of an air bearing testbed and two inverted pendulums is devised on the basic of equivalent mass and equivalent stiffness proposed firstly in this paper.And the dynamic model of the simulator equivalent to the sensitive axis motion of the test mass and the planar motion of the satellite is derived from the Euler-Lagrange method.Then,the dynamic equivalence conditions between the space prototype system and the ground model system are derived from Pi theorem.To satisfy these conditions,the scaling laws of two systems and requirements for the inverted pendulum are put forward.Besides,the corresponding control scaling laws and a closed-loop control strategy are deduced and applied to establishing the numerical simulation experiments of underactuated system.Subsequently,the comparative simulation results demonstrate the similarity of dynamical behavior between the scaled-down ground model and the space prototype.As a result,the rationality and effectiveness of the design method are proved,facilitating the ground simulation of future gravitational wave detection satellites.展开更多
Objective:Several reports have proposed that lnc RNAs,as potential biomarkers,participate in the progression and growth of malignant tumors.HIF1 A-AS2 is a novel lnc RNA and potential biomarker,involved in the genesis...Objective:Several reports have proposed that lnc RNAs,as potential biomarkers,participate in the progression and growth of malignant tumors.HIF1 A-AS2 is a novel lnc RNA and potential biomarker,involved in the genesis and development of carcinomas.However,the molecular mechanism of HIF1 A-AS2 in renal carcinoma is unclear.Methods:The relative expression levels of HIF1 A-AS2 and miR-30 a-5 p were detected using RT-qPCR in renal carcinoma tissues and cell lines.Using loss-of-function and overexpression,the biological effects of HIF1 A-AS2 and miR-30 a-5 p in kidney carcinoma progression were characterized.Dual luciferase reporter gene analysis and Western blot were used to detect the potential mechanism of HIF1 A-AS2 in renal carcinomas.Results:HIF1 A-AS2 was upregulated in kidney carcinoma tissues when compared with para-carcinoma tissues(P<0.05).In addition,tumor size,tumor node mestastasis stage and differentiation were identified as being closely associated with HIF1 A-AS2 expression(P<0.05).Knockdown or overexpression of HIF1 A-AS2 either restrained or promoted the malignant phenotype and WNT/β-catenin signaling in renal carcinoma cells(P<0.05).Mi R-30 a-5 p was downregulated in renal cancers and partially reversed HIF1 A-AS2 functions in malignant renal tumor cells.HIF1 A-AS2 acted as a micro RNA sponge that actively regulated the relative expression of SOX4 in sponging miR-30 a-5 p and subsequently increased the malignant phenotypes of renal carcinomas.HIF1 A-AS2 showed a carcinogenic effect and miR-30 a-5 p acted as an antagonist of the anti-oncogene effects in the pathogenesis of renal carcinomas.Conclusions:The HIF1 A-AS2-miR-30 a-5 p-SOX4 axis was associated with the malignant progression and development of renal carcinoma.The relative expression of HIF1 A-AS2 was negatively correlated with the expression of miR-30 a-5 p,and was closely correlated with SOX4 mRNA levels in renal cancers.展开更多
Nanocrystalline metals often display a high strength up to the gigapascal level,yet they suffer from poor plasticity.Previous studies have shown that the development of hetero-sized grains can efficiently overcome the...Nanocrystalline metals often display a high strength up to the gigapascal level,yet they suffer from poor plasticity.Previous studies have shown that the development of hetero-sized grains can efficiently overcome the strength-ductility trade-off of nanocrystalline metals.However,whether this strategy can lead to the fabrication of nanocrystalline nanowires exhibiting both high strength and superplasticity is unclear,similar to the atomistic deformation mechanism.In this paper,we show that ultra-small nanocrystalline Au nanowires comprising grains in both the Hall–Petch and inverse Hall–Petch grain-size regions can exhibit extremely high uniform elongation(236%)and high strength(2.34 gigapascals)at room temperature.In situ atomic-scale observations revealed that the plastic deformation underwent two stages.In the first stage,the super-elongation ability originated from the intergrain plasticity of small grains via mechanisms such as grain boundary migration and grain rotation.This intergrain plasticity caused the grains in the heterogeneous-structured nanowires to grow very large.In the second stage,the superelongation ability originated from intragrain plasticity accompanied by the diffusion of surface atoms.Our results show that the hetero-grain-sized nanocrystalline nanowires,comprising grains with sizes both in the strongest Hall–Petch effect region and the inverse Hall–Petch effect region,were simultaneously ultrastrong and ductile.They displayed neither a strength-ductility trade-off nor plastic instability.展开更多
Titanium diboride(TiB_(2))is an effective grain refiner of Al alloys in the industry that facilitates casting processes by forming uniformly refined microstructures.Although our understanding of the underlying refinem...Titanium diboride(TiB_(2))is an effective grain refiner of Al alloys in the industry that facilitates casting processes by forming uniformly refined microstructures.Although our understanding of the underlying refinement mechanisms has advanced,the atomic kinetics of heterogeneous nucleation of Al on TiB2 remains unknown.Here,we report atomic-scale observations of the heterogeneous nucleation and growth kinetics of Al on self-formed TiB_(2) particles by in situ heating of undercooled Al-5Ti-1B films.We demonstrate that an ordered Al monolayer forms on the Ti-terminated{0001}TiB_(2) surface;then,the surrounding Al atoms are initiated to form an island-shaped Al nucleus with face-centered cubic{111}stacking without the assistance of a Ti-rich buffer layer.The interfacial lattice mismatch between{111}Al and{0001}TiB_(2) causes remarkable out-of-plane strain that decreases gradually with Al nucleus layers increasing to 6 atomic layers.The elastic strain energy originating from this interfacial strain increases the free energy of the Al/TiB2 heterostructure,hence impeding the rapid growth of the Al nucleus.We found that TiB2 particles stabilize the Al nuclei rather than activating their free growth into grains when the experimental undercoolingΔT is lower than the onset undercoolingΔT fg in Greer's free growth model.Our findings provide an atomic-scale physical image of the heterogeneous nucleation and growth mechanisms of Al with inoculator participation and elucidate the strain-dependent growth kinetics of Al nuclei.展开更多
WRKY transcription factors(TFs)have been identified as important core regulators in the responses of plants to biotic and abiotic stresses.Cultivated peanut(Arachis hypogaea)is an important oil and protein crop.Previo...WRKY transcription factors(TFs)have been identified as important core regulators in the responses of plants to biotic and abiotic stresses.Cultivated peanut(Arachis hypogaea)is an important oil and protein crop.Previous studies have identified hundreds of WRKY TFs in peanut.However,their functions and regulatory networks remain unclear.Simultaneously,the AdWRKY40 TF is involved in drought tolerance in Arachis duranensis and has an orthologous relationship with the AhTWRKY24 TF,which has a homoeologous relationship with AhTWRKY106 TF in A.hypogaea cv.Tifrunner.To reveal how the homoeologous AhTWRKY24 and AhTWRKY106 TFs regulate the downstream genes,DNA affinity purification sequencing(DAP-seq)was performed to detect the binding sites of TFs at the genome-wide level.A total of 3486 downstream genes were identified that were collectively regulated by the AhTWRKY24 and AhTWRKY106 TFs.The results revealed that W-box elements were the binding sites for regulation of the downstream genes by AhTWRKY24 and AhTWRKY106 TFs.A gene ontology enrichment analysis indicated that these downstream genes were enriched in protein modification and reproduction in the biological process.In addition,RNA-seq data showed that the AhTWRKY24 and AhTWRKY106 TFs regulate differentially expressed genes involved in the response to drought stress.The AhTWRKY24 and AhTWRKY106 TFs can specifically regulate downstream genes,and they nearly equal the numbers of downstream genes from the two A.hypogaea cv.Tifrunner subgenomes.These results provide a theoretical basis to study the functions and regulatory networks of AhTWRKY24 and AhTWRKY106 TFs.展开更多
Chemical randomness and the associated energy fluctuation are essential features of multi-principal ele-ment alloys(MPEAs).Due to these features,nanoscale stacking fault energy(SFE)fluctuation is a natural and indepen...Chemical randomness and the associated energy fluctuation are essential features of multi-principal ele-ment alloys(MPEAs).Due to these features,nanoscale stacking fault energy(SFE)fluctuation is a natural and independent contribution to strengthening MPEAs.However,existing models for conventional alloys(i.e.,alloys with one principal element)cannot be applied to MPEAs.The extreme values of SFEs required by such models are unknown for MPEAs,which need to calculate the nanoscale volume relevant to the SFE fluctuation.In the present work,we developed an analytic model to evaluate the strengthening ef-fect through the SFE fluctuation,profuse in MPEAs.The model has no adjustable parameters,and all parameters can be determined from experiments and ab initio calculations.This model explains available experimental observations and provides insightful guidance for designing new MPEAs based on the SFE fluctuation.It generally applies to MPEAs in random states and with chemical short-range order.展开更多
Ovarian endometrioma(OE),also known as“chocolate cysts,”is a cystic mass that develops in the ovaries due to endometriosis and is a common gynecological condition characterized by the growth of endometrial tissue ou...Ovarian endometrioma(OE),also known as“chocolate cysts,”is a cystic mass that develops in the ovaries due to endometriosis and is a common gynecological condition characterized by the growth of endometrial tissue outside the uterus,leading to symptoms such as dysmenorrhea,pelvic pain,and infertility.However,the precise molecular and cellular mechanisms driving this pathophysiology remain largely unknown,posing challenges for diagnosis and treatment.Here,we employed integrated single-cell transcriptomic profiling of over 52,000 individual cells from endometrial tissues of OE patients and healthy donors and identified twelve major cell populations.We identified notable alterations in cell type-specific proportions and molecular signatures associated with OE.Notably,the activation of IGFBP5^(+) macrophages with pro-inflammatory properties,NK cell exhaustion,and aberrant proliferation of IQCG^(+) and KLF2^(+) epithelium are key features and may be the potential mechanisms underlying the pathogenesis of OE.Collectively,our data contribute to a better understanding of OE at the single cell level and may pave the way for the development of novel therapeutic strategies.展开更多
SiC_(f)/SiBCZr composites were prepared by polymer precursor impregnation and pyrolysis process with near stoichiometric ratio SiC fiber preform as reinforcement phase and SiBCZr multiphase ceramic precursor as impreg...SiC_(f)/SiBCZr composites were prepared by polymer precursor impregnation and pyrolysis process with near stoichiometric ratio SiC fiber preform as reinforcement phase and SiBCZr multiphase ceramic precursor as impregnating reagent.The results highlighted that the SiC_(f)/SiBCZr composites exhibited excellent ablative properties after ablative tests at 1200℃/3600 s and 1400℃/3600 s,and the strength retention rates of the composites reached 90%and 85%,respectively.This was mainly due to the liquid sealing effect of the ablative products represented by B2O_(3) and SiO_(2)∙B_(2)O_(3),which inhibited the ablative reaction by reducing the diffusion rate of the oxidation medium,and the solid pinning effect of the substances represented by SiO_(2),ZrO_(2),and ZrSiO_(4),which could play high viscosity and high strength characteristics to improve anti-erosion ability.The above-mentioned SiC_(f)/SiBCZr composites with corrosion resistance,oxidation resistance,and ablative resistance provided a solid material foundation and technical support for the development of reusable spacecraft hot-end components.展开更多
High entropy alloys(HEAs)have attracted much attention for their excellent mechanical properties stem-ming from diverse deformation mechanisms.Particularly,face-centered cubic(FCC)to body-centered cu-bic(BCC)martensit...High entropy alloys(HEAs)have attracted much attention for their excellent mechanical properties stem-ming from diverse deformation mechanisms.Particularly,face-centered cubic(FCC)to body-centered cu-bic(BCC)martensitic transformation is crucial for enhancing the strength and plasticity of HEAs,partic-ularly at cryogenic temperatures.However,the fundamental atomic mechanism underlying martensitic transformation remains elusive,and the impact of martensitic transformation on the mechanical prop-erties of HEAs at room temperature is unknown.Here,we report in situ atomic-scale observation of a reversible martensitic transformation from FCC to body-centered tetragonal(BCT)and ultimately back to FCC in the nanostructured CrMnFeCoNi HEA at room temperature under deformation.This martensitic transformation is completed by the synergistic action of 90°partial dislocations slip on(111)FCC plane and atom shuffling,involving the periodic arrangement and slip of two 90°half Shockley partial disloca-tions a/12[112](111)and one 90°Shockley partial dislocation-a/6[112](111)on three successive(111)FCC atomic planes.Additionally,the reversible phase transformation induced by high stress dissipates strain energies and hinders crack propagation,thereby enhancing the fracture toughness of HEAs.Our findings contribute to a deeper comprehension of the martensitic transformation mechanisms in HEAs,offering valuable insights for improving their mechanical properties.展开更多
随着数据科学和材料科学的进步,人们如今可构建出较为准确的人工智能模型,用于材料性质预测.本文中,我们以170,714个无机晶体化合物的高通量第一性原理计算数据集为基础,训练得到了可精确预测无机化合物形成能的机器学习模型.相比于同...随着数据科学和材料科学的进步,人们如今可构建出较为准确的人工智能模型,用于材料性质预测.本文中,我们以170,714个无机晶体化合物的高通量第一性原理计算数据集为基础,训练得到了可精确预测无机化合物形成能的机器学习模型.相比于同类工作,本项研究以超大数据集为出发点,构建出无机晶体形成能的高精度泛化模型,可外推至广阔相空间,其中的Dense Net神经网络模型精度可以达到R^(2)=0.982和平均绝对误差(MAE)=0.072 eV atom^(-1).上述模型精度的提升源自一系列新型特征描述符,这些描述符可有效提取出原子与领域原子间的电负性和局域结构等信息,从而精确捕捉到原子间的相互作用.本文为新材料搜索提供了一种高效、低成本的结合能预测手段.展开更多
Direct formic acid fuel cells （DFAFCs） allow highly efficient low temperature conversion of chemical energy into electricity and are expected to play a vital role in our future sustainable society. However, the mass...Direct formic acid fuel cells （DFAFCs） allow highly efficient low temperature conversion of chemical energy into electricity and are expected to play a vital role in our future sustainable society. However, the massive precious metal usage in current membrane electrode assembly （MEA） technology greatly inhibits their actual applications. Here we demonstrate a new type of anode constructed by confining highly active nanoengineered catalysts into an ultra-thin catalyst layer with thickness around 100 nm. Specifically, an atomic layer of platinum is first deposited onto nanoporous gold （NPG） leaf to achieve high utilization of Pt and easy accessibility of both reactants and electrons to active sites. These NPG-Pt core/shell nanostructures are further decorated by a sub-monolayer of Bi to create highly active reaction sites for formic acid electro-oxidation. Thus obtained layer-structured NPG-Pt-Bi thin films allow a dramatic decrease in Pt usage down to 3 ~tg.cm-2, while maintaining very high electrode activity and power performance at sufficiently low overall precious metal loading. Moreover, these electrode materials show superior durability during half-year test in actual DFAFCs, with remarkable resistance to common impurities in formic acid, which together imply their great potential in applications in actual devices.展开更多
Sodium-ion batteries are promising for large-scale energy storage due to sodium's low cost and infinite abundance. The most popular cathodes for sodium-ion batteries, i.e., the layered sodium-containing oxides, us...Sodium-ion batteries are promising for large-scale energy storage due to sodium's low cost and infinite abundance. The most popular cathodes for sodium-ion batteries, i.e., the layered sodium-containing oxides, usually exhibit reversible host rearrangement between P-type and O-type stacking upon charge/discharge. Herein we demonstrate that such host rearrangement is unfavorable and can be suppressed by introducing transition-metal ions into sodium layers. The electrode with stabilized P3-type stacking delivers superior rate capability, high energy efficiency, and excellent cycling performance. Owing to the cation-mixing nature, it performs the lowest lattice strain among all reported cathodes for sodium-ion batteries. Our findings highlight the significance of a stable host for sodium-ion storage and moreover underline the fundamental distinction in material design strategy between lithium-and sodium-ion batteries.展开更多
This paper presents a micromachined electrochemical angular accelerometer with highly integrated sensitive microelectrodes.Theoretical analyses and numerical simulations were conducted to model the angular acceleromet...This paper presents a micromachined electrochemical angular accelerometer with highly integrated sensitive microelectrodes.Theoretical analyses and numerical simulations were conducted to model the angular accelerometer with key geometrical parameters(e.g.,electrode spacing,via spacing and via size)optimized.Highly integrated sensitive microelectrodes were manufactured based on microfabrication and assembled to form MEMS-based electrochemical angular accelerometers.Device characterization was conducted,locating a sensitivity of 80 V/(rad/s^(2)),a bandwidth of 0.01–18 Hz and a noise level of 3.98×10^(−8)(rad/s^(2))/√Hz.In comparison to a previously reported electrochemical angular microaccelerometer,a significant improvement in sensitivity(80 V/(rad/s^(2))vs.10 V/(rad/s^(2)))was achieved due to the new structure of sensitive microelectrodes.These results indicated the potential of the developed MEMS-based electrochemical angular accelerometer in seismology,including natural disaster monitoring and resource exploration.展开更多
Scanning tunneling microscopy/spectroscopy(STM/STS)at 4.8 K has been used to examine the growth of a double-decker bis(phthalocyaninato)yttrium(YP_(c2))molecule on a reconstructed Au(111)substrate.Local differential c...Scanning tunneling microscopy/spectroscopy(STM/STS)at 4.8 K has been used to examine the growth of a double-decker bis(phthalocyaninato)yttrium(YP_(c2))molecule on a reconstructed Au(111)substrate.Local differential conductance spectra(dI/dV)of a single YPc2 molecule allow the characteristics of the highest occupied molecular orbital(HOMO)and the lowest unoccupied molecular orbital(LUMO)to be identified.Furthermore,lateral distributions of the local density of states(LDOS)have also been obtained by dI/dV mapping and confirmed by first principles simulations.These electronic feature mappings and theoretical calculations provide a basis for understanding the unique STM morphology of YPc2,which is usually imaged as an eight-lobed structure.In addition,we demonstrate that bias-dependent STM morphologies and simultaneous dI/dV maps can provide a way of understanding the stability of two-dimensional YP_(c2) films.展开更多
A new electrochemical angular microaccelerometer with integrated sensitive electrodes perpendicular to flow channels was developed in this paper.Based on a liquid inertial mass,an incoming angular acceleration was tra...A new electrochemical angular microaccelerometer with integrated sensitive electrodes perpendicular to flow channels was developed in this paper.Based on a liquid inertial mass,an incoming angular acceleration was translated into varied concentrations of reactive ions around sensitive microelectrodes,generating a detection current.Key structural parameters of the sensitive microelectrodes were designed and compared based on theoretical analysis and numerical simulations.An angular microaccelerometer incorporating sensitive microelectrodes was then fabricated,assembled and characterized,producing a sensitivity of 338 V/(rad/s^(2)),a-3 dB bandwidth of 0.01-10 Hz and a noise level of 4.67×10^(-8)(rad/s^(2))/Hz^(1/2)@1 Hz.These performances were better than their commercial counterparts based on traditional electrodes and previously reported microaccelerometers based on microsensitive electrodes in parallel with flow channels,which can be applied to measure rotational accelerations in earthquakes and buildings.展开更多
Background The coronavirus disease 2019(COVID-19)cases continue to rise,and the demand for medical treatment and resources in healthcare systems surges.Assessing the viral shedding time(VST)of patients with COVID-19 c...Background The coronavirus disease 2019(COVID-19)cases continue to rise,and the demand for medical treatment and resources in healthcare systems surges.Assessing the viral shedding time(VST)of patients with COVID-19 can facilitate clinical decision making.Although some studies have been conducted on the factors affecting the VST of severe acute respiratory syndrome coronavirus 2(SARS-COV-2),few prediction models are currently available.Methods This retrospective study included the consecutive patients with COVID-19 admitted to Xi’an Chest Hospital in Shaanxi,China,for treatment between December 19,2021 and February 5,2022.The clinical data of the patients were extracted from their electronic medical records.Combining significant factors affecting the VST,a nomogram was developed to predict the VST of the SARS-CoV-2 Delta variant in patients with COVID-19.Results We included 332 patients in this study.The average VST was 21 d.VST was significantly prolonged in patients with severe clinical symptoms,sore throat,old age,long time from onset to diagnosis,and an abnormal white blood cell count.Consequently,we developed a nomogram prediction model using these 5 variables.The concordance index(C-index)of this nomogram was 0.762,and after internal validation using bootstrapping(1000 resamples),the adjusted C-index was 0.762.The area under the nomogram’s receiver operator characteristic curve showed good discriminative ability(0.965).The calibration curve showed high consistency.The VST was prolonged in the group with lower model fitting scores according to the Kaplan-Meier curve(χ2=286,log-rank P<0.001).Conclusions We developed a nomogram for predicting VST based on 5 easily accessible factors.It can effectively estimate the appropriate isolation period,control viral transmission,and optimize clinical strategies.展开更多
CONSPECTUS:This Account will provide an overview and analysis on recent research of 3D nanoporous graphene based single-atom electrocatalysts for energy conversion and storage applications.In order to meet the increas...CONSPECTUS:This Account will provide an overview and analysis on recent research of 3D nanoporous graphene based single-atom electrocatalysts for energy conversion and storage applications.In order to meet the increasing energy demands and assist in the transition from a global economy that relies heavily on fossil fuels to one that utilizes more renewable energy sources,there is urgent need to develop highperforming electrocatalysts toward renewable energy related reactions.These catalysts are expected to have low overpotentials,high reaction selectivity,long cycling stability,and,importantly,lower materials costs to address the challenges of traditional nanoparticulate noble metal catalysts.展开更多
基金supported by the National Key Research and Development Program of China (Grant No.2021YFC2202604)the Strategy Priority Research Program of Chinese Academy of Sciences (Grant No.XDA1502110101).
文摘The ground-based experimental tests are crucial to verify the related technologies of the drag-free satellite.This work presents a design method of the ground simulator testbed for emulating the planar dynamics of the space drag-free systems.In this paper,the planar dynamic characteristics of the drag-free satellite with double test masses are analyzed and nondimensionalized.A simulator vehicle composed of an air bearing testbed and two inverted pendulums is devised on the basic of equivalent mass and equivalent stiffness proposed firstly in this paper.And the dynamic model of the simulator equivalent to the sensitive axis motion of the test mass and the planar motion of the satellite is derived from the Euler-Lagrange method.Then,the dynamic equivalence conditions between the space prototype system and the ground model system are derived from Pi theorem.To satisfy these conditions,the scaling laws of two systems and requirements for the inverted pendulum are put forward.Besides,the corresponding control scaling laws and a closed-loop control strategy are deduced and applied to establishing the numerical simulation experiments of underactuated system.Subsequently,the comparative simulation results demonstrate the similarity of dynamical behavior between the scaled-down ground model and the space prototype.As a result,the rationality and effectiveness of the design method are proved,facilitating the ground simulation of future gravitational wave detection satellites.
基金supported by grants from the National Natural Science Foundations of China(Grant Nos.81702511,81472401,81772708,and 2016YFA0201204)the Jiangsu Provincial Key Medical Discipline(Grant No.ZDXKA2016012)+1 种基金the Clinical Medicine Center of Suzhou(Grant No.SZZXJ201501)programs for Recruitment of Clinical Medical Top Team of Suzhou。
文摘Objective:Several reports have proposed that lnc RNAs,as potential biomarkers,participate in the progression and growth of malignant tumors.HIF1 A-AS2 is a novel lnc RNA and potential biomarker,involved in the genesis and development of carcinomas.However,the molecular mechanism of HIF1 A-AS2 in renal carcinoma is unclear.Methods:The relative expression levels of HIF1 A-AS2 and miR-30 a-5 p were detected using RT-qPCR in renal carcinoma tissues and cell lines.Using loss-of-function and overexpression,the biological effects of HIF1 A-AS2 and miR-30 a-5 p in kidney carcinoma progression were characterized.Dual luciferase reporter gene analysis and Western blot were used to detect the potential mechanism of HIF1 A-AS2 in renal carcinomas.Results:HIF1 A-AS2 was upregulated in kidney carcinoma tissues when compared with para-carcinoma tissues(P<0.05).In addition,tumor size,tumor node mestastasis stage and differentiation were identified as being closely associated with HIF1 A-AS2 expression(P<0.05).Knockdown or overexpression of HIF1 A-AS2 either restrained or promoted the malignant phenotype and WNT/β-catenin signaling in renal carcinoma cells(P<0.05).Mi R-30 a-5 p was downregulated in renal cancers and partially reversed HIF1 A-AS2 functions in malignant renal tumor cells.HIF1 A-AS2 acted as a micro RNA sponge that actively regulated the relative expression of SOX4 in sponging miR-30 a-5 p and subsequently increased the malignant phenotypes of renal carcinomas.HIF1 A-AS2 showed a carcinogenic effect and miR-30 a-5 p acted as an antagonist of the anti-oncogene effects in the pathogenesis of renal carcinomas.Conclusions:The HIF1 A-AS2-miR-30 a-5 p-SOX4 axis was associated with the malignant progression and development of renal carcinoma.The relative expression of HIF1 A-AS2 was negatively correlated with the expression of miR-30 a-5 p,and was closely correlated with SOX4 mRNA levels in renal cancers.
基金financially supported by the Beijing Natural Science Foundation(No.Z180014)the National Natural Foundation of China(No.11902014)。
文摘Nanocrystalline metals often display a high strength up to the gigapascal level,yet they suffer from poor plasticity.Previous studies have shown that the development of hetero-sized grains can efficiently overcome the strength-ductility trade-off of nanocrystalline metals.However,whether this strategy can lead to the fabrication of nanocrystalline nanowires exhibiting both high strength and superplasticity is unclear,similar to the atomistic deformation mechanism.In this paper,we show that ultra-small nanocrystalline Au nanowires comprising grains in both the Hall–Petch and inverse Hall–Petch grain-size regions can exhibit extremely high uniform elongation(236%)and high strength(2.34 gigapascals)at room temperature.In situ atomic-scale observations revealed that the plastic deformation underwent two stages.In the first stage,the super-elongation ability originated from the intergrain plasticity of small grains via mechanisms such as grain boundary migration and grain rotation.This intergrain plasticity caused the grains in the heterogeneous-structured nanowires to grow very large.In the second stage,the superelongation ability originated from intragrain plasticity accompanied by the diffusion of surface atoms.Our results show that the hetero-grain-sized nanocrystalline nanowires,comprising grains with sizes both in the strongest Hall–Petch effect region and the inverse Hall–Petch effect region,were simultaneously ultrastrong and ductile.They displayed neither a strength-ductility trade-off nor plastic instability.
基金financially supported by the National Natural Science Foundation of China(Nos.52173224,51821001,52130105,and 52273230)the Natural Science Foundation of Shanghai(No.21ZR1431200)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning.
文摘Titanium diboride(TiB_(2))is an effective grain refiner of Al alloys in the industry that facilitates casting processes by forming uniformly refined microstructures.Although our understanding of the underlying refinement mechanisms has advanced,the atomic kinetics of heterogeneous nucleation of Al on TiB2 remains unknown.Here,we report atomic-scale observations of the heterogeneous nucleation and growth kinetics of Al on self-formed TiB_(2) particles by in situ heating of undercooled Al-5Ti-1B films.We demonstrate that an ordered Al monolayer forms on the Ti-terminated{0001}TiB_(2) surface;then,the surrounding Al atoms are initiated to form an island-shaped Al nucleus with face-centered cubic{111}stacking without the assistance of a Ti-rich buffer layer.The interfacial lattice mismatch between{111}Al and{0001}TiB_(2) causes remarkable out-of-plane strain that decreases gradually with Al nucleus layers increasing to 6 atomic layers.The elastic strain energy originating from this interfacial strain increases the free energy of the Al/TiB2 heterostructure,hence impeding the rapid growth of the Al nucleus.We found that TiB2 particles stabilize the Al nuclei rather than activating their free growth into grains when the experimental undercoolingΔT is lower than the onset undercoolingΔT fg in Greer's free growth model.Our findings provide an atomic-scale physical image of the heterogeneous nucleation and growth mechanisms of Al with inoculator participation and elucidate the strain-dependent growth kinetics of Al nuclei.
基金funded by the Start-up Foundation for High Talents of Qingdao Agricultural University(No.665/1120012)the Natural Science Foundation of Shandong Province,China(ZR2019QC017)+4 种基金the National Key Research and Development Program,China(2022YFD2300101-1)the Key Research and Development Program of Shandong Province,China(2021LZGC003 and 2021LZGC026-03)Peanut Seed Industry Project in Shandong Province,China(2022LZGC007)the Science&Technology Specific Projects in Agricultural High-tech Industrial Demonstration Area of the Yellow River Delta,China(2022SZX18)the Graduate Student Innovation Program of Qingdao Agricultural University(QNYCX23001).
文摘WRKY transcription factors(TFs)have been identified as important core regulators in the responses of plants to biotic and abiotic stresses.Cultivated peanut(Arachis hypogaea)is an important oil and protein crop.Previous studies have identified hundreds of WRKY TFs in peanut.However,their functions and regulatory networks remain unclear.Simultaneously,the AdWRKY40 TF is involved in drought tolerance in Arachis duranensis and has an orthologous relationship with the AhTWRKY24 TF,which has a homoeologous relationship with AhTWRKY106 TF in A.hypogaea cv.Tifrunner.To reveal how the homoeologous AhTWRKY24 and AhTWRKY106 TFs regulate the downstream genes,DNA affinity purification sequencing(DAP-seq)was performed to detect the binding sites of TFs at the genome-wide level.A total of 3486 downstream genes were identified that were collectively regulated by the AhTWRKY24 and AhTWRKY106 TFs.The results revealed that W-box elements were the binding sites for regulation of the downstream genes by AhTWRKY24 and AhTWRKY106 TFs.A gene ontology enrichment analysis indicated that these downstream genes were enriched in protein modification and reproduction in the biological process.In addition,RNA-seq data showed that the AhTWRKY24 and AhTWRKY106 TFs regulate differentially expressed genes involved in the response to drought stress.The AhTWRKY24 and AhTWRKY106 TFs can specifically regulate downstream genes,and they nearly equal the numbers of downstream genes from the two A.hypogaea cv.Tifrunner subgenomes.These results provide a theoretical basis to study the functions and regulatory networks of AhTWRKY24 and AhTWRKY106 TFs.
基金sponsored by the U.S.Department of En-ergy,Office of Science,Basic Energy Sciences,Materials Science and Engineering Divisionsupported by the Office of Science of the U.S.Department of Energy under Contract No.DE-AC05-00OR22725+2 种基金the supports from(1)the National Science Foundation(DMR-1611180 and 1809640)with program directors,Drs.J.Yang,G.Shifletthe US Army Research Office(W911NF-13-1-0438 and W911NF-19-2-0049)with program managers,Drs.M.P.Bakas,S.N.Math-audhuthe support of U.S.Na-tional Science Foundation under grant DMR-1804320.
文摘Chemical randomness and the associated energy fluctuation are essential features of multi-principal ele-ment alloys(MPEAs).Due to these features,nanoscale stacking fault energy(SFE)fluctuation is a natural and independent contribution to strengthening MPEAs.However,existing models for conventional alloys(i.e.,alloys with one principal element)cannot be applied to MPEAs.The extreme values of SFEs required by such models are unknown for MPEAs,which need to calculate the nanoscale volume relevant to the SFE fluctuation.In the present work,we developed an analytic model to evaluate the strengthening ef-fect through the SFE fluctuation,profuse in MPEAs.The model has no adjustable parameters,and all parameters can be determined from experiments and ab initio calculations.This model explains available experimental observations and provides insightful guidance for designing new MPEAs based on the SFE fluctuation.It generally applies to MPEAs in random states and with chemical short-range order.
基金supported from Scientific and Technological Innovation Project of China Academy of Chinese Medical Sciences(CI2023D003,CI2021B014)the National Key Research and Development Program of China(2022YFC2303600,2020YFA0908000)+8 种基金the Innovation Team and Talents Cultivation Program of National Administration of Traditional Chinese Medicine(ZYYCXTD-C-202002)the CACMS Innovation Fund(CI2023E002,CI2021A05101,CI2021A05104)the Science and Technology Foundation o f Shenzhen(JCYJ20210324115800001)the Science and Technology Foundation of Shenzhen(Shenzhen Clinical Medical Research Center for Geriatric Diseases)the Shenzhen Medical Research Fund(B2302051)the National Natural Science Foundation of China(82201786)Guangdong Basic and Applied Basic Research Foundation(2021A1515110646)Guangdong-Dongguan Joint Fund Regional Cultivation Project(2021B1515140033)Dongguan Science and Technology of Social Development Program(20211800904742,20221800905732,20221800904462).
文摘Ovarian endometrioma(OE),also known as“chocolate cysts,”is a cystic mass that develops in the ovaries due to endometriosis and is a common gynecological condition characterized by the growth of endometrial tissue outside the uterus,leading to symptoms such as dysmenorrhea,pelvic pain,and infertility.However,the precise molecular and cellular mechanisms driving this pathophysiology remain largely unknown,posing challenges for diagnosis and treatment.Here,we employed integrated single-cell transcriptomic profiling of over 52,000 individual cells from endometrial tissues of OE patients and healthy donors and identified twelve major cell populations.We identified notable alterations in cell type-specific proportions and molecular signatures associated with OE.Notably,the activation of IGFBP5^(+) macrophages with pro-inflammatory properties,NK cell exhaustion,and aberrant proliferation of IQCG^(+) and KLF2^(+) epithelium are key features and may be the potential mechanisms underlying the pathogenesis of OE.Collectively,our data contribute to a better understanding of OE at the single cell level and may pave the way for the development of novel therapeutic strategies.
文摘SiC_(f)/SiBCZr composites were prepared by polymer precursor impregnation and pyrolysis process with near stoichiometric ratio SiC fiber preform as reinforcement phase and SiBCZr multiphase ceramic precursor as impregnating reagent.The results highlighted that the SiC_(f)/SiBCZr composites exhibited excellent ablative properties after ablative tests at 1200℃/3600 s and 1400℃/3600 s,and the strength retention rates of the composites reached 90%and 85%,respectively.This was mainly due to the liquid sealing effect of the ablative products represented by B2O_(3) and SiO_(2)∙B_(2)O_(3),which inhibited the ablative reaction by reducing the diffusion rate of the oxidation medium,and the solid pinning effect of the substances represented by SiO_(2),ZrO_(2),and ZrSiO_(4),which could play high viscosity and high strength characteristics to improve anti-erosion ability.The above-mentioned SiC_(f)/SiBCZr composites with corrosion resistance,oxidation resistance,and ablative resistance provided a solid material foundation and technical support for the development of reusable spacecraft hot-end components.
基金the Natural Science Foundation of China(Nos.52173224,52130105)the Natural Science Foundation of Shanghai(No.21ZR1431200)+2 种基金Shanghai Jiao Tong University-JA Solar New Energy Materials Joint Research Center.Shufen Chu is supported by the China Postdoctoral Science Foundation(No.2023M742218)Fan Zhang is supported by the National Key Lab-oratory Foundation of Science and Technology on Materials under Shock and Impact(No.WDZC2022-1)the National Natural Sci-ence Foundation of China((No.52271141).
文摘High entropy alloys(HEAs)have attracted much attention for their excellent mechanical properties stem-ming from diverse deformation mechanisms.Particularly,face-centered cubic(FCC)to body-centered cu-bic(BCC)martensitic transformation is crucial for enhancing the strength and plasticity of HEAs,partic-ularly at cryogenic temperatures.However,the fundamental atomic mechanism underlying martensitic transformation remains elusive,and the impact of martensitic transformation on the mechanical prop-erties of HEAs at room temperature is unknown.Here,we report in situ atomic-scale observation of a reversible martensitic transformation from FCC to body-centered tetragonal(BCT)and ultimately back to FCC in the nanostructured CrMnFeCoNi HEA at room temperature under deformation.This martensitic transformation is completed by the synergistic action of 90°partial dislocations slip on(111)FCC plane and atom shuffling,involving the periodic arrangement and slip of two 90°half Shockley partial disloca-tions a/12[112](111)and one 90°Shockley partial dislocation-a/6[112](111)on three successive(111)FCC atomic planes.Additionally,the reversible phase transformation induced by high stress dissipates strain energies and hinders crack propagation,thereby enhancing the fracture toughness of HEAs.Our findings contribute to a deeper comprehension of the martensitic transformation mechanisms in HEAs,offering valuable insights for improving their mechanical properties.
基金the financial support from the Chinese Academy of Sciences(CAS-WX2021PY-0102,ZDBS-LY-SLH007,and XDB33020000)。
文摘随着数据科学和材料科学的进步,人们如今可构建出较为准确的人工智能模型,用于材料性质预测.本文中,我们以170,714个无机晶体化合物的高通量第一性原理计算数据集为基础,训练得到了可精确预测无机化合物形成能的机器学习模型.相比于同类工作,本项研究以超大数据集为出发点,构建出无机晶体形成能的高精度泛化模型,可外推至广阔相空间,其中的Dense Net神经网络模型精度可以达到R^(2)=0.982和平均绝对误差(MAE)=0.072 eV atom^(-1).上述模型精度的提升源自一系列新型特征描述符,这些描述符可有效提取出原子与领域原子间的电负性和局域结构等信息,从而精确捕捉到原子间的相互作用.本文为新材料搜索提供了一种高效、低成本的结合能预测手段.
文摘Direct formic acid fuel cells （DFAFCs） allow highly efficient low temperature conversion of chemical energy into electricity and are expected to play a vital role in our future sustainable society. However, the massive precious metal usage in current membrane electrode assembly （MEA） technology greatly inhibits their actual applications. Here we demonstrate a new type of anode constructed by confining highly active nanoengineered catalysts into an ultra-thin catalyst layer with thickness around 100 nm. Specifically, an atomic layer of platinum is first deposited onto nanoporous gold （NPG） leaf to achieve high utilization of Pt and easy accessibility of both reactants and electrons to active sites. These NPG-Pt core/shell nanostructures are further decorated by a sub-monolayer of Bi to create highly active reaction sites for formic acid electro-oxidation. Thus obtained layer-structured NPG-Pt-Bi thin films allow a dramatic decrease in Pt usage down to 3 ~tg.cm-2, while maintaining very high electrode activity and power performance at sufficiently low overall precious metal loading. Moreover, these electrode materials show superior durability during half-year test in actual DFAFCs, with remarkable resistance to common impurities in formic acid, which together imply their great potential in applications in actual devices.
基金The financial support from the National Basic Research Program of China(2014CB932300)Natural Science Foundation of Jiangsu Province of China(BK20170630)+1 种基金NSF of China(21633003 and 51602144)sponsored by the JST-CREST ‘‘Phase Interface Science for Highly Efficient Energy Utilization",JST(Japan)
文摘Sodium-ion batteries are promising for large-scale energy storage due to sodium's low cost and infinite abundance. The most popular cathodes for sodium-ion batteries, i.e., the layered sodium-containing oxides, usually exhibit reversible host rearrangement between P-type and O-type stacking upon charge/discharge. Herein we demonstrate that such host rearrangement is unfavorable and can be suppressed by introducing transition-metal ions into sodium layers. The electrode with stabilized P3-type stacking delivers superior rate capability, high energy efficiency, and excellent cycling performance. Owing to the cation-mixing nature, it performs the lowest lattice strain among all reported cathodes for sodium-ion batteries. Our findings highlight the significance of a stable host for sodium-ion storage and moreover underline the fundamental distinction in material design strategy between lithium-and sodium-ion batteries.
基金supported by the Strategic Priority Research Program(A)of the Chinese Academy of Sciences(Grant No.XDA22020302)the National Natural Science Foundation of China for Distinguished Young Scholars(Grant No.61825107)+2 种基金the National Natural Science Foundation of China(62071454,62061136012)the Innovation Research Group Project of National Natural Science Foundation of China(Grant No.62121003)the Scientific Instrument Development Project of the Chinese Academy of Sciences(Grant No.JJSTD20210004).
文摘This paper presents a micromachined electrochemical angular accelerometer with highly integrated sensitive microelectrodes.Theoretical analyses and numerical simulations were conducted to model the angular accelerometer with key geometrical parameters(e.g.,electrode spacing,via spacing and via size)optimized.Highly integrated sensitive microelectrodes were manufactured based on microfabrication and assembled to form MEMS-based electrochemical angular accelerometers.Device characterization was conducted,locating a sensitivity of 80 V/(rad/s^(2)),a bandwidth of 0.01–18 Hz and a noise level of 3.98×10^(−8)(rad/s^(2))/√Hz.In comparison to a previously reported electrochemical angular microaccelerometer,a significant improvement in sensitivity(80 V/(rad/s^(2))vs.10 V/(rad/s^(2)))was achieved due to the new structure of sensitive microelectrodes.These results indicated the potential of the developed MEMS-based electrochemical angular accelerometer in seismology,including natural disaster monitoring and resource exploration.
基金The first author acknowledges the financial support of JSPS(Japan Society for the Promotion of Science)This work was also supported by an International Colla-borative Research Grant by the National Institute of Information and Communications Technology of Japan.
文摘Scanning tunneling microscopy/spectroscopy(STM/STS)at 4.8 K has been used to examine the growth of a double-decker bis(phthalocyaninato)yttrium(YP_(c2))molecule on a reconstructed Au(111)substrate.Local differential conductance spectra(dI/dV)of a single YPc2 molecule allow the characteristics of the highest occupied molecular orbital(HOMO)and the lowest unoccupied molecular orbital(LUMO)to be identified.Furthermore,lateral distributions of the local density of states(LDOS)have also been obtained by dI/dV mapping and confirmed by first principles simulations.These electronic feature mappings and theoretical calculations provide a basis for understanding the unique STM morphology of YPc2,which is usually imaged as an eight-lobed structure.In addition,we demonstrate that bias-dependent STM morphologies and simultaneous dI/dV maps can provide a way of understanding the stability of two-dimensional YP_(c2) films.
基金the National Natural Science Foundation of China(62071454,62061136012)the National Natural Science Foundation of China for Distinguished Young Scholars(Grant no.61825107)+2 种基金the Innovation Research Group Project of National Natural Science Foundation of China(Grant no.62121003)the Scientific Instrument Developing Project of the Chinese Academy of Sciences(Grant no.JJSTD20210004)the Strategic Priority Research Program(A)of the Chinese Academy of Sciences(Grant no.XDA22020302).
文摘A new electrochemical angular microaccelerometer with integrated sensitive electrodes perpendicular to flow channels was developed in this paper.Based on a liquid inertial mass,an incoming angular acceleration was translated into varied concentrations of reactive ions around sensitive microelectrodes,generating a detection current.Key structural parameters of the sensitive microelectrodes were designed and compared based on theoretical analysis and numerical simulations.An angular microaccelerometer incorporating sensitive microelectrodes was then fabricated,assembled and characterized,producing a sensitivity of 338 V/(rad/s^(2)),a-3 dB bandwidth of 0.01-10 Hz and a noise level of 4.67×10^(-8)(rad/s^(2))/Hz^(1/2)@1 Hz.These performances were better than their commercial counterparts based on traditional electrodes and previously reported microaccelerometers based on microsensitive electrodes in parallel with flow channels,which can be applied to measure rotational accelerations in earthquakes and buildings.
基金supported by the Clinical Research Award of the First Affiliated Hospital of Xi’an Jiaotong University,China(XJTU1AF-CRF-2018-025).
文摘Background The coronavirus disease 2019(COVID-19)cases continue to rise,and the demand for medical treatment and resources in healthcare systems surges.Assessing the viral shedding time(VST)of patients with COVID-19 can facilitate clinical decision making.Although some studies have been conducted on the factors affecting the VST of severe acute respiratory syndrome coronavirus 2(SARS-COV-2),few prediction models are currently available.Methods This retrospective study included the consecutive patients with COVID-19 admitted to Xi’an Chest Hospital in Shaanxi,China,for treatment between December 19,2021 and February 5,2022.The clinical data of the patients were extracted from their electronic medical records.Combining significant factors affecting the VST,a nomogram was developed to predict the VST of the SARS-CoV-2 Delta variant in patients with COVID-19.Results We included 332 patients in this study.The average VST was 21 d.VST was significantly prolonged in patients with severe clinical symptoms,sore throat,old age,long time from onset to diagnosis,and an abnormal white blood cell count.Consequently,we developed a nomogram prediction model using these 5 variables.The concordance index(C-index)of this nomogram was 0.762,and after internal validation using bootstrapping(1000 resamples),the adjusted C-index was 0.762.The area under the nomogram’s receiver operator characteristic curve showed good discriminative ability(0.965).The calibration curve showed high consistency.The VST was prolonged in the group with lower model fitting scores according to the Kaplan-Meier curve(χ2=286,log-rank P<0.001).Conclusions We developed a nomogram for predicting VST based on 5 easily accessible factors.It can effectively estimate the appropriate isolation period,control viral transmission,and optimize clinical strategies.
基金supported by the Whiting School of Engineering,Johns Hopkins University,and the National Science Foundation(NSF DMR-1804320)a JSPS Grant-in-Aid for Early-Career Scientists(19K15389)a JSPS Grant-in-Aid for Research Activity Start-up(18H05939)。
文摘CONSPECTUS:This Account will provide an overview and analysis on recent research of 3D nanoporous graphene based single-atom electrocatalysts for energy conversion and storage applications.In order to meet the increasing energy demands and assist in the transition from a global economy that relies heavily on fossil fuels to one that utilizes more renewable energy sources,there is urgent need to develop highperforming electrocatalysts toward renewable energy related reactions.These catalysts are expected to have low overpotentials,high reaction selectivity,long cycling stability,and,importantly,lower materials costs to address the challenges of traditional nanoparticulate noble metal catalysts.
