In order to satisfy the machining requirements of aero-engine casing in modern aviation industry, this paper investigates three main issues during the design and development process of a five-axis machine tool with hi...In order to satisfy the machining requirements of aero-engine casing in modern aviation industry, this paper investigates three main issues during the design and development process of a five-axis machine tool with high accuracy, stiffness and efficiency, including whole structure design,key components design, and supporting stiffness design. First, an appropriate structure of five-axis machine tool is determined considering the processing characteristics of aero-engine casing. Then, a dual drive swing head and a compact motorized spindle are designed with enough drive capability and stiffness, and related structure, assembly method, cooling technology, and performance simulation are given in detail. Next, a design method of supporting stiffness of guide is proposed through the deformation prediction of the spindle end. Based on above work, a prototype of machine tool is developed, and some experiments are carried out, including performance tests of swing head and motorized spindle, and machining of a simulated workpiece of aero-engine casing. All experimental results show that the machine tool has satisfactory accuracy, stiffness and efficiency, which meets the machining requirements of aero-engine casing. The main work can be used as references for engineers and technicians, which are meaningful in practice.展开更多
In this paper,the CuO-CeO_(2) catalyst was prepared by a direct solvothermal method.The effects of different copper salt precursors(copper nitrate,copper acetate,copper sulfate) on the catalytic performa nce of the pr...In this paper,the CuO-CeO_(2) catalyst was prepared by a direct solvothermal method.The effects of different copper salt precursors(copper nitrate,copper acetate,copper sulfate) on the catalytic performa nce of the prepared catalyst fo r CO oxidation were investigated.The physical and chemical properties of the prepared catalysts were characterized by X-ray diffraction(XRD),Raman spectroscopy,N_(2)physical adsorption,inductively coupled plasma-atomic emission spectrometry(ICP-AES),X-ray photoelectron spectroscopy(XPS),temperature-programmed desorption analysis of CO(CO-TPD),in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTs),and temperature-programmed reduction with H_(2)(H_(2)-TPR).The results show that the CuO-CeO_(2)catalyst prepared with copper acetate as precursor(CC-A) exhibits the best catalytic activity for CO oxidation at low temperatures,with T50and T90values of 62 and 78℃ respectively,which is mainly attributed to its large specific surface area,pore volume,CO adsorption capacity,and large amount and strong reactivity of surface oxygen.However,the CuO-CeO_(2) catalyst prepared with copper nitrate as precursor(CC-N) displays better stability and resistance to water or CO_(2) poisoning than CC-A.展开更多
Nasopharyngeal carcinoma(NPC)is a malignancy originating from the nasopharyngeal epithelial cells.Although some studies have identified potential biomarkers for early diagnosis of NPC based on metabolomics data(Chen e...Nasopharyngeal carcinoma(NPC)is a malignancy originating from the nasopharyngeal epithelial cells.Although some studies have identified potential biomarkers for early diagnosis of NPC based on metabolomics data(Chen et al.,2023;Zhou et al.,2023)and Epstein-Barr virus subtypes(Xu et al.,2019),their effectiveness and applicability need further investigation,particularly when consideringthe roles of oral microbiota.展开更多
In this paper, we have proposed an upper bound for the largest Z-eigenvalue of an irreducible weakly symmetric and nonnegative tensor, which is called the Brauer upper bound:■where■ As applications, a bound on the Z...In this paper, we have proposed an upper bound for the largest Z-eigenvalue of an irreducible weakly symmetric and nonnegative tensor, which is called the Brauer upper bound:■where■ As applications, a bound on the Z-spectral radius of uniform hypergraphs is presented.展开更多
A dual-route optical emission spectroscopy(D-OES)diagnostic is newly developed to monitor the optical emission from the X-point plasma region on the HL-2 A tokamak.This diagnostic is composed of an imaging system,a be...A dual-route optical emission spectroscopy(D-OES)diagnostic is newly developed to monitor the optical emission from the X-point plasma region on the HL-2 A tokamak.This diagnostic is composed of an imaging system,a beam-splitting system for dual-route measurements,fiber bundles,a spectrometer system,and a control and acquisition system.One route is used to obtain wide-spectral-range spectra,and the other route is used to acquire high-wavelengthresolution line shapes.The spectral resolution of the wide-range spectrometers is 0.8 nm with a coverage of 800 nm(@200-1000 nm).The spectral resolution of the high-resolution spectrometer is 0.01 nm with a coverage of 6 nm(@200-660 nm).The spatial resolution of each route of D-OES is about 4 cm with 11 channels.The temporal resolution is 16 ms at maximum in the single-channel mode.Wide-range spectra(containing Balmer series and a Fulcher band)and highly resolved Ha line shapes are obtained by D-OES in the hydrogen glow discharge in the lab.D-OES measurements are carried out in the high-density deuterium experiments of HL-2A.The electron density n_(e)and deuterium temperature T_(D) in the X-point multifaceted asymmetric radiation from the edge(MARFE)region are derived simultaneously by fitting the measured D_(a) shape.The density n_(e)is observed to increase from~8.7×10^(18)m^(-3)to~7.8×10^(19)m^(-3),and the temperature T_(D)drops from~14.4 eV to~2.3 eV after the onset of MARFE in the discharge#38260.展开更多
Drought is a major abiotic stress limiting agricultural crops production worldwide.In our study,we isolated a novel C2H2-type zinc finger protein gene ZF2 from chickpea.ZF2 consisted of 232 amino acids with two QALGGH...Drought is a major abiotic stress limiting agricultural crops production worldwide.In our study,we isolated a novel C2H2-type zinc finger protein gene ZF2 from chickpea.ZF2 consisted of 232 amino acids with two QALGGH motifs in Cys2/His2 zinc finger domain.Transient expression analysis of ZF2:GFP fusion protein showed that ZF2 was a nuclear localized protein.In the yeast assay system,the full-length of ZF2 did not show transcriptional activation.Expression of ZF2 gene was enhanced by treatments of several abiotic stresses and phytohormones.The promoter region of ZF2 contained multiple stress-and hormone-related cis-elements.Overexpression of ZF2 in Arabidopsis significantly improved the root length and fresh weight at seedling stage and enhanced the survival rates and proline content under drought treatment.These results indicated that ZF2 functioned as a positive regulator in drought response.展开更多
In this paper, we give a note on the eigenvalue localization sets for tensors. We show that these sets are tighter than those provided by Li et al. (2014) [1].
Online streaming feature selection(OSFS),as an online learning manner to handle streaming features,is critical in addressing high-dimensional data.In real big data-related applications,the patterns and distributions o...Online streaming feature selection(OSFS),as an online learning manner to handle streaming features,is critical in addressing high-dimensional data.In real big data-related applications,the patterns and distributions of streaming features constantly change over time due to dynamic data generation environments.However,existing OSFS methods rely on presented and fixed hyperparameters,which undoubtedly lead to poor selection performance when encountering dynamic features.To make up for the existing shortcomings,the authors propose a novel OSFS algorithm based on vague set,named OSFSVague.Its main idea is to combine uncertainty and three-way decision theories to improve feature selection from the traditional dichotomous method to the trichotomous method.OSFS-Vague also improves the calculation method of correlation between features and labels.Moreover,OSFS-Vague uses the distance correlation coefficient to classify streaming features into relevant features,weakly redundant features,and redundant features.Finally,the relevant features and weakly redundant features are filtered for an optimal feature set.To evaluate the proposed OSFS-Vague,extensive empirical experiments have been conducted on 11 datasets.The results demonstrate that OSFS-Vague outperforms six state-of-the-art OSFS algorithms in terms of selection accuracy and computational efficiency.展开更多
High-conductivity sliding electrical contact with low friction plays a significant role in the long life and high reliability of electromechanical systems.Reducing friction needs weak interfacial electronic coupling;i...High-conductivity sliding electrical contact with low friction plays a significant role in the long life and high reliability of electromechanical systems.Reducing friction needs weak interfacial electronic coupling;in contrast,enhancing conductivity requires strong coupling;thus it is a serious challenge to achieve high conductivity with low friction.Here,using our self-developed thermally assisted mechanical exfoliation and transfer(TAMET)method,we experimentally achieved superlubricating electrical contact by establishing a sliding electrical system between graphite layers(Gr);the friction coefficient was as low as 0.0004,and the electric current density was as high as 510 A/cm2.Compared with the commercial Ir atomic force microscopy(AFM)tip–Gr contact,the friction force of incommensurate graphene layer friction is an order of magnitude lower,yet it has a similar high electrical conductivity.On the basis of the electronic property fluctuation(EPF)model and first principles calculations,we revealed that the sliding energy barrier remains almost unchanged under an applied current because of the negligible electron transfer variation during the sliding process.We offer a method for achieving superlubricating electrical contact with high conductivity and low friction,shedding light on improving the service life and reliability of sliding electrical contacts in a wide range of electromechanical systems.展开更多
Introduction:In the early stages of the coronavirus disease 2019(COVID-19)epidemic in China,the highest level of public health emergency response(Level 1 Response)was launched in all province-level administrative divi...Introduction:In the early stages of the coronavirus disease 2019(COVID-19)epidemic in China,the highest level of public health emergency response(Level 1 Response)was launched in all province-level administrative divisions(PLADs)across the country.Provision of vaccination services was selectively suspended due to the physical distancing and gathering restrictions required of Level 1 Response.The purpose of this paper is to evaluate the impact of COVID-19 on vaccination services and the effectiveness of selective vaccination service suspension and catch-up vaccinations in China.Methods:Vaccine doses administered,routine vaccination coverage levels,catch-up vaccine doses administered,and coverage levels after the catch-up campaign were determined from individual vaccination records in sampled clinics,standard routine immunization administrative coverage reports,and catch-up vaccination activity reports submitted by PLADs between October 2019 and October 2020.Results:National Immunization Program(NIP)and non-NIP vaccine doses administered in sampled clinics decreased by 80% and 90%,respectively,compared with doses administered before the COVID-19 pandemic.Coverage with the birth dose of hepatitis B vaccine(HepB1)and the Bacillus Calmette-Guérin vaccine(BCG)—two vaccinations recommended to continue throughout the epidemic due to their timecritical nature—were maintained at over 85%,while coverage of other NIP vaccines decreased to below 60%by February 2020.Catch-up vaccination coverage of the 29 PLADs,excluding Xinjiang and Xizang(Tibet),began in April 2020 and exceeded 90%;Hubei catch-up coverage was 95% by October 2020.Conclusions and Implications for Public Health Practice:The COVID-19 pandemic had a great impact on China’s vaccination services.During the epidemic and time of local transmission of the coronavirus,HepB1,BCG,rabies vaccine for postexposure prophylaxis,and tetanus antitoxin(TAT)for wound prophylaxis were maintained at high levels.Of the 69 million vaccine doses postponed during the time of local transmission of the coronavirus,94% were administered in the catch-up campaign.China’s pandemic immunization practices may provide evidence for other countries’immunization programs.展开更多
To the Editor:Dilated cardiomyopathy(DCM)is a type of primary myocardial disease with unknown etiology.[1]It is a disorder of the heart muscle mainly characterized by left ventricular dilation and systolic dysfunction...To the Editor:Dilated cardiomyopathy(DCM)is a type of primary myocardial disease with unknown etiology.[1]It is a disorder of the heart muscle mainly characterized by left ventricular dilation and systolic dysfunction,resulting from the response of the myocardium to genetic and environmental insults.The clinical manifestations arc progressive heart failure,arrhythmia,thromboembolism,and even sudden death.展开更多
Inorganic phosphorus(Pi)deficiency significantly impacts plant growth,development,and photosynthetic efficiency.This study evaluated 206 rice accessions from a MiniCore population under both Pi-sufficient(Pi^(+))and P...Inorganic phosphorus(Pi)deficiency significantly impacts plant growth,development,and photosynthetic efficiency.This study evaluated 206 rice accessions from a MiniCore population under both Pi-sufficient(Pi^(+))and Pi-starvation(Pi^(-))conditions in the field to assess photosynthetic phosphorus use efficiency(PPUE),defined as the ratio of A_(sat)^(Pi^(-))to A_(sat)^(Pi^(+)).A genome-wide association study and differential gene expression analyses identified an acid phosphatase gene(ACP2)that responds strongly to phosphate availability.Overexpression and knockout of ACP2 led to a 67%increase and 32%decrease in PPUE,respectively,compared with wild type.Introduction of an elite allele A,by substituting the v5 SNP G with A,resulted in an 18%increase in PPUE in gene-edited ACP2 rice lines.The phosphate-responsive gene PHR2 was found to transcriptionally activate ACP2 in parallel with PHR2 overexpression,resulting in an 11%increase in PPUE.Biochemical assays indicated that ACP2 primarily catalyzes the hydrolysis of phosphoethanolamine and phospho-L-serine.In addition,serine levels increased significantly in the ACP2^(vBG)overexpression line,along with a concomitant decrease in the expression of all nine genes involved in the photorespiratory pathway.Application of serine enhanced PPUE and reduced photorespiration rates in ACP2 mutants under Pi-starvation conditions.We deduce that ACP2 plays a crucial role in promoting photosynthesis adaptation to Pi starvation by regulating serine metabolism in rice.展开更多
In late December 2019,clinicians in Hubei Province noticed and reported to health authorities a cluster of cases of pneumonia of unknown etiology(PUE)that turned out to be the start of the coronavirus disease 2019(COV...In late December 2019,clinicians in Hubei Province noticed and reported to health authorities a cluster of cases of pneumonia of unknown etiology(PUE)that turned out to be the start of the coronavirus disease 2019(COVID-19)pandemic(1).By January 29,2020,all provincial-level administrative divisions(PLADs)across the country had launched their highest public health emergency responses(Level 1 responses)(2-3).展开更多
Let ■ be a k-uniform hypergraph on n vertices with degree sequence △= d1≥…≥ dn =δ. In this paper, in terms of degree di , we give some upper bounds for the Z-spectral radius of the signless Laplacian tensor (Q(...Let ■ be a k-uniform hypergraph on n vertices with degree sequence △= d1≥…≥ dn =δ. In this paper, in terms of degree di , we give some upper bounds for the Z-spectral radius of the signless Laplacian tensor (Q(■)) of ■. Some examples are given to show the efficiency of these bounds.展开更多
To the Editor:Autoimmune hepatitis(AIH)is a type of liver parenchymal inflammation mediated by the autoimmune response of liver cells.AIH was previously considered to be a chronic liver disease,but recent observers ha...To the Editor:Autoimmune hepatitis(AIH)is a type of liver parenchymal inflammation mediated by the autoimmune response of liver cells.AIH was previously considered to be a chronic liver disease,but recent observers have confirmed that AIH patients can have acute onset or even liver failure(AIH-LF).[1]The incidence of AIH-LF has also increased.Once LF occurs,the mortality rate within 90 days could reach>40%.[2]Therefore,the occurrence of LF has a major impact on the prognosis of AIH.Although AIH-LF has a low incidence and a high mortality rate,some cases can still be cured by treatment.The clinical characteristics that may affect the prognosis of patients with AIH-LF are still unclear.To clarify the factors affecting the prognosis of AIH-LF,we compared the clinical characteristics of two groups of AIH-LF patients with different prognosis.展开更多
China CDC’s National Immunization Program’s Senior Research Scholars Program(NIP-SRSP)is a program created to foster the professional development of early-to-mid-career immunization experts,strengthen knowledge exch...China CDC’s National Immunization Program’s Senior Research Scholars Program(NIP-SRSP)is a program created to foster the professional development of early-to-mid-career immunization experts,strengthen knowledge exchange and cooperation between national and provincial/prefectural-level CDCs,and deepen scientific and programmatic capacity of the National Immunization Program and provincial/prefectural immunization programs.Initiated in September 2019.展开更多
基金co-supported by the Natural Science Foundation of Beijing(No.3214043)the Project of State Key Lab of Tribology of Tsinghua University(No.SKLT2021D16)the National Natural Science Foundation of China(No.51975319)。
文摘In order to satisfy the machining requirements of aero-engine casing in modern aviation industry, this paper investigates three main issues during the design and development process of a five-axis machine tool with high accuracy, stiffness and efficiency, including whole structure design,key components design, and supporting stiffness design. First, an appropriate structure of five-axis machine tool is determined considering the processing characteristics of aero-engine casing. Then, a dual drive swing head and a compact motorized spindle are designed with enough drive capability and stiffness, and related structure, assembly method, cooling technology, and performance simulation are given in detail. Next, a design method of supporting stiffness of guide is proposed through the deformation prediction of the spindle end. Based on above work, a prototype of machine tool is developed, and some experiments are carried out, including performance tests of swing head and motorized spindle, and machining of a simulated workpiece of aero-engine casing. All experimental results show that the machine tool has satisfactory accuracy, stiffness and efficiency, which meets the machining requirements of aero-engine casing. The main work can be used as references for engineers and technicians, which are meaningful in practice.
基金Project supported by the National Natural Science Foundation of China (21273150)。
文摘In this paper,the CuO-CeO_(2) catalyst was prepared by a direct solvothermal method.The effects of different copper salt precursors(copper nitrate,copper acetate,copper sulfate) on the catalytic performa nce of the prepared catalyst fo r CO oxidation were investigated.The physical and chemical properties of the prepared catalysts were characterized by X-ray diffraction(XRD),Raman spectroscopy,N_(2)physical adsorption,inductively coupled plasma-atomic emission spectrometry(ICP-AES),X-ray photoelectron spectroscopy(XPS),temperature-programmed desorption analysis of CO(CO-TPD),in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTs),and temperature-programmed reduction with H_(2)(H_(2)-TPR).The results show that the CuO-CeO_(2)catalyst prepared with copper acetate as precursor(CC-A) exhibits the best catalytic activity for CO oxidation at low temperatures,with T50and T90values of 62 and 78℃ respectively,which is mainly attributed to its large specific surface area,pore volume,CO adsorption capacity,and large amount and strong reactivity of surface oxygen.However,the CuO-CeO_(2) catalyst prepared with copper nitrate as precursor(CC-N) displays better stability and resistance to water or CO_(2) poisoning than CC-A.
基金supported by the National Key R&D Program of China(2022YFA1204000 to T.D.)the Guangdong Key Area Research and Development Program(2019B020228001 to T.D.)the National Natural Science Foundation of China(81971906 to T.D.).
文摘Nasopharyngeal carcinoma(NPC)is a malignancy originating from the nasopharyngeal epithelial cells.Although some studies have identified potential biomarkers for early diagnosis of NPC based on metabolomics data(Chen et al.,2023;Zhou et al.,2023)and Epstein-Barr virus subtypes(Xu et al.,2019),their effectiveness and applicability need further investigation,particularly when consideringthe roles of oral microbiota.
基金Supported by the High-Level Innovative Talents of Guizhou ProvinceScience and Technology Fund Project of GZInnovative Talent Team in Guizhou Province(Grant Nos.Zun Ke He Ren Cai[2017]8,Qian Ke He J Zi LKZS[2012]08,Qian Ke HE Pingtai Rencai[2016]5619.)
文摘In this paper, we have proposed an upper bound for the largest Z-eigenvalue of an irreducible weakly symmetric and nonnegative tensor, which is called the Brauer upper bound:■where■ As applications, a bound on the Z-spectral radius of uniform hypergraphs is presented.
基金supported by the National MCF Energy R&D Program of China(Nos.2018YFE0301102,2022YFE03100004 and 2018YFE 0303102)National Natural Science Foundation of China(Nos.12375210 and 12305238)the Sichuan Natural Science Foundation(Nos.2022NSFSC1791,2022JDRC0014 and 2022TFQCCXTD)。
文摘A dual-route optical emission spectroscopy(D-OES)diagnostic is newly developed to monitor the optical emission from the X-point plasma region on the HL-2 A tokamak.This diagnostic is composed of an imaging system,a beam-splitting system for dual-route measurements,fiber bundles,a spectrometer system,and a control and acquisition system.One route is used to obtain wide-spectral-range spectra,and the other route is used to acquire high-wavelengthresolution line shapes.The spectral resolution of the wide-range spectrometers is 0.8 nm with a coverage of 800 nm(@200-1000 nm).The spectral resolution of the high-resolution spectrometer is 0.01 nm with a coverage of 6 nm(@200-660 nm).The spatial resolution of each route of D-OES is about 4 cm with 11 channels.The temporal resolution is 16 ms at maximum in the single-channel mode.Wide-range spectra(containing Balmer series and a Fulcher band)and highly resolved Ha line shapes are obtained by D-OES in the hydrogen glow discharge in the lab.D-OES measurements are carried out in the high-density deuterium experiments of HL-2A.The electron density n_(e)and deuterium temperature T_(D) in the X-point multifaceted asymmetric radiation from the edge(MARFE)region are derived simultaneously by fitting the measured D_(a) shape.The density n_(e)is observed to increase from~8.7×10^(18)m^(-3)to~7.8×10^(19)m^(-3),and the temperature T_(D)drops from~14.4 eV to~2.3 eV after the onset of MARFE in the discharge#38260.
基金sponsored by the National Natural Science Foundation of China(31160306 and 30860152)Natural Science Foundation of Zhejiang Province(LQ20C130003)+1 种基金Scientific Research Fund of Zhejiang Provincial Education Department(Y202145972 and Y202248468)Zhejiang Students’Technology and Innovation Program(Xinmiao Program)(2022R485A003).
文摘Drought is a major abiotic stress limiting agricultural crops production worldwide.In our study,we isolated a novel C2H2-type zinc finger protein gene ZF2 from chickpea.ZF2 consisted of 232 amino acids with two QALGGH motifs in Cys2/His2 zinc finger domain.Transient expression analysis of ZF2:GFP fusion protein showed that ZF2 was a nuclear localized protein.In the yeast assay system,the full-length of ZF2 did not show transcriptional activation.Expression of ZF2 gene was enhanced by treatments of several abiotic stresses and phytohormones.The promoter region of ZF2 contained multiple stress-and hormone-related cis-elements.Overexpression of ZF2 in Arabidopsis significantly improved the root length and fresh weight at seedling stage and enhanced the survival rates and proline content under drought treatment.These results indicated that ZF2 functioned as a positive regulator in drought response.
文摘In this paper, we give a note on the eigenvalue localization sets for tensors. We show that these sets are tighter than those provided by Li et al. (2014) [1].
基金Science and Technology Project of Zunyi,Grant/Award Number:ZSKRPT[2023]3Excellent Young Scientific and Technological Talents Foundation of Guizhou Province,Grant/Award Number:QKHplatform talent(2021)5627+4 种基金Science and Technology Top Talent Project of Guizhou Education Department,Grant/Award Number:QJJ2022(088)the Guizhou Provincial Department of Education Colleges and Universities Science and Technology Innovation Team,Grant/Award Number:QJJ[2023]084National Natural Science Foundation of China,Grant/Award Numbers:62066049,62221005,61936001,62176070Department of Education of Guizhou Province,Grant/Award Number:QJJ[2023]084Science and Technology Foundation of State Grid Corporation of China,Grant/Award Number:1400-202357341A-1-1-ZN。
文摘Online streaming feature selection(OSFS),as an online learning manner to handle streaming features,is critical in addressing high-dimensional data.In real big data-related applications,the patterns and distributions of streaming features constantly change over time due to dynamic data generation environments.However,existing OSFS methods rely on presented and fixed hyperparameters,which undoubtedly lead to poor selection performance when encountering dynamic features.To make up for the existing shortcomings,the authors propose a novel OSFS algorithm based on vague set,named OSFSVague.Its main idea is to combine uncertainty and three-way decision theories to improve feature selection from the traditional dichotomous method to the trichotomous method.OSFS-Vague also improves the calculation method of correlation between features and labels.Moreover,OSFS-Vague uses the distance correlation coefficient to classify streaming features into relevant features,weakly redundant features,and redundant features.Finally,the relevant features and weakly redundant features are filtered for an optimal feature set.To evaluate the proposed OSFS-Vague,extensive empirical experiments have been conducted on 11 datasets.The results demonstrate that OSFS-Vague outperforms six state-of-the-art OSFS algorithms in terms of selection accuracy and computational efficiency.
基金the National Natural Science Foundation of China(Nos.52105171,52225502,and 52305200)the China National Postdoctoral Program for Innovative Talents(No.BX20220176),the China Postdoctoral Science Foundation(No.2023M731945)the Key Research and Development Program of Yunnan Province(No.202203ZA080001).
文摘High-conductivity sliding electrical contact with low friction plays a significant role in the long life and high reliability of electromechanical systems.Reducing friction needs weak interfacial electronic coupling;in contrast,enhancing conductivity requires strong coupling;thus it is a serious challenge to achieve high conductivity with low friction.Here,using our self-developed thermally assisted mechanical exfoliation and transfer(TAMET)method,we experimentally achieved superlubricating electrical contact by establishing a sliding electrical system between graphite layers(Gr);the friction coefficient was as low as 0.0004,and the electric current density was as high as 510 A/cm2.Compared with the commercial Ir atomic force microscopy(AFM)tip–Gr contact,the friction force of incommensurate graphene layer friction is an order of magnitude lower,yet it has a similar high electrical conductivity.On the basis of the electronic property fluctuation(EPF)model and first principles calculations,we revealed that the sliding energy barrier remains almost unchanged under an applied current because of the negligible electron transfer variation during the sliding process.We offer a method for achieving superlubricating electrical contact with high conductivity and low friction,shedding light on improving the service life and reliability of sliding electrical contacts in a wide range of electromechanical systems.
基金funded by grants from the Vaccine Preventable Diseases and Immunization(VDI)of World Health Organization Office in China(No.2020/1017283-0).
文摘Introduction:In the early stages of the coronavirus disease 2019(COVID-19)epidemic in China,the highest level of public health emergency response(Level 1 Response)was launched in all province-level administrative divisions(PLADs)across the country.Provision of vaccination services was selectively suspended due to the physical distancing and gathering restrictions required of Level 1 Response.The purpose of this paper is to evaluate the impact of COVID-19 on vaccination services and the effectiveness of selective vaccination service suspension and catch-up vaccinations in China.Methods:Vaccine doses administered,routine vaccination coverage levels,catch-up vaccine doses administered,and coverage levels after the catch-up campaign were determined from individual vaccination records in sampled clinics,standard routine immunization administrative coverage reports,and catch-up vaccination activity reports submitted by PLADs between October 2019 and October 2020.Results:National Immunization Program(NIP)and non-NIP vaccine doses administered in sampled clinics decreased by 80% and 90%,respectively,compared with doses administered before the COVID-19 pandemic.Coverage with the birth dose of hepatitis B vaccine(HepB1)and the Bacillus Calmette-Guérin vaccine(BCG)—two vaccinations recommended to continue throughout the epidemic due to their timecritical nature—were maintained at over 85%,while coverage of other NIP vaccines decreased to below 60%by February 2020.Catch-up vaccination coverage of the 29 PLADs,excluding Xinjiang and Xizang(Tibet),began in April 2020 and exceeded 90%;Hubei catch-up coverage was 95% by October 2020.Conclusions and Implications for Public Health Practice:The COVID-19 pandemic had a great impact on China’s vaccination services.During the epidemic and time of local transmission of the coronavirus,HepB1,BCG,rabies vaccine for postexposure prophylaxis,and tetanus antitoxin(TAT)for wound prophylaxis were maintained at high levels.Of the 69 million vaccine doses postponed during the time of local transmission of the coronavirus,94% were administered in the catch-up campaign.China’s pandemic immunization practices may provide evidence for other countries’immunization programs.
基金333 project of Jiangsu Province(Grant/Award Number:BRA2017544)Project of Qinghai Science and Technology Department(Grant/Award Number:2018-SF-114)+1 种基金Zhongnanshan Medical Foundation of Guangdong Province(No.ZNSA-2020017)Guiding project of Qinghai Health Commission(Grant/Award Number:2019-wjzdx-35)。
文摘To the Editor:Dilated cardiomyopathy(DCM)is a type of primary myocardial disease with unknown etiology.[1]It is a disorder of the heart muscle mainly characterized by left ventricular dilation and systolic dysfunction,resulting from the response of the myocardium to genetic and environmental insults.The clinical manifestations arc progressive heart failure,arrhythmia,thromboembolism,and even sudden death.
基金supported by the National Natural Science Foundation of China(32170245,32260447)Natural Science Foundation of Zhejiang Province(LQ20C130003)+4 种基金Sanya Yazhou Bay Science and Technology City(SCKJ-JYRC-2022-04)Scientific Research Fund of Zhejiang Provincial Education Department(YZ0Z145972)Huzhou Public Welfare Application Research Project(2021GZ26)National Training Programs of Innovation and Entrepreneurship for Undergraduates(2022hzxy019)Guangzhou Science and Technology Planning Project(202201010790).
文摘Inorganic phosphorus(Pi)deficiency significantly impacts plant growth,development,and photosynthetic efficiency.This study evaluated 206 rice accessions from a MiniCore population under both Pi-sufficient(Pi^(+))and Pi-starvation(Pi^(-))conditions in the field to assess photosynthetic phosphorus use efficiency(PPUE),defined as the ratio of A_(sat)^(Pi^(-))to A_(sat)^(Pi^(+)).A genome-wide association study and differential gene expression analyses identified an acid phosphatase gene(ACP2)that responds strongly to phosphate availability.Overexpression and knockout of ACP2 led to a 67%increase and 32%decrease in PPUE,respectively,compared with wild type.Introduction of an elite allele A,by substituting the v5 SNP G with A,resulted in an 18%increase in PPUE in gene-edited ACP2 rice lines.The phosphate-responsive gene PHR2 was found to transcriptionally activate ACP2 in parallel with PHR2 overexpression,resulting in an 11%increase in PPUE.Biochemical assays indicated that ACP2 primarily catalyzes the hydrolysis of phosphoethanolamine and phospho-L-serine.In addition,serine levels increased significantly in the ACP2^(vBG)overexpression line,along with a concomitant decrease in the expression of all nine genes involved in the photorespiratory pathway.Application of serine enhanced PPUE and reduced photorespiration rates in ACP2 mutants under Pi-starvation conditions.We deduce that ACP2 plays a crucial role in promoting photosynthesis adaptation to Pi starvation by regulating serine metabolism in rice.
文摘In late December 2019,clinicians in Hubei Province noticed and reported to health authorities a cluster of cases of pneumonia of unknown etiology(PUE)that turned out to be the start of the coronavirus disease 2019(COVID-19)pandemic(1).By January 29,2020,all provincial-level administrative divisions(PLADs)across the country had launched their highest public health emergency responses(Level 1 responses)(2-3).
基金Science and Technology Foundation of Guizhou Province (Qian Ke He Ji Chu [2016]1161)Natural Science Foundation of Guizhou Province (Qian Jiao He KY [2016]255)+9 种基金Doctoral Scientific Research Foundation of Zunyi Normal College (BS[2015]09)Yanmin Liu was supported by the National Natural Science Foundations of China (Grant No. 71461027)Science and Technology Talent Training Object of Guizhou Province Outstanding Youth (Qian Ke He Ren Zi [2015]06)Natural Science Foundation of Guizhou Province (Qian Jiao He KY [2014]295), 2013. 2014, 2015 Zunyi 15851 Talents Elite Project FundingZunyi Innovative Talent Team (Zunyi KH (2015)38)Junkang Tian was supported by the Natural Science Foundation of Guizhou Province (Qian Jiao He KY [2015]451)Science and Technology Foundation of Guizhou Province (Qian Ke He J Zi [2015]2147)Xianghu Liu was supported by the Guizhou Province Department of Education Fund (KY[2015]391,[2016]046)Guizhou Province Department of Education Teaching Reform Project ([2015]337)Guizhou Province Science and Technology Fund (qian Ke He Ji Chu [2016]1160).
文摘Let ■ be a k-uniform hypergraph on n vertices with degree sequence △= d1≥…≥ dn =δ. In this paper, in terms of degree di , we give some upper bounds for the Z-spectral radius of the signless Laplacian tensor (Q(■)) of ■. Some examples are given to show the efficiency of these bounds.
基金supported by grants from the National Key R&D Program of China(No.2017YFA0103000)the National Science and Technology Key Project on"Major Infectious Diseases such as HIV/AIDS,Viral Hepatitis Prevention and Treatment"(Nos.2012ZX10002004-006,2017ZX10203201-005,2017ZX10201201-001-001,2017ZX10201201-002-002,2017ZX10201201-004-002,2017ZX10202203-006-001,2017ZX10302201-004-002)+3 种基金the"Beijing Municipal Administration of Hospitals"Ascent Plan(No.DFL20151601)the Beijing Municipal Administration of Hospitals Clinical Medicine Development of Special Funding Support(No.ZYLX201806)the Science and Technology Innovation Service Capacity Building-high-precision Discipline Construction Project(No.11920703)the Open research project of Key Laboratory of Capital Medical University(No.BJYAHKF2017008)。
文摘To the Editor:Autoimmune hepatitis(AIH)is a type of liver parenchymal inflammation mediated by the autoimmune response of liver cells.AIH was previously considered to be a chronic liver disease,but recent observers have confirmed that AIH patients can have acute onset or even liver failure(AIH-LF).[1]The incidence of AIH-LF has also increased.Once LF occurs,the mortality rate within 90 days could reach>40%.[2]Therefore,the occurrence of LF has a major impact on the prognosis of AIH.Although AIH-LF has a low incidence and a high mortality rate,some cases can still be cured by treatment.The clinical characteristics that may affect the prognosis of patients with AIH-LF are still unclear.To clarify the factors affecting the prognosis of AIH-LF,we compared the clinical characteristics of two groups of AIH-LF patients with different prognosis.
文摘China CDC’s National Immunization Program’s Senior Research Scholars Program(NIP-SRSP)is a program created to foster the professional development of early-to-mid-career immunization experts,strengthen knowledge exchange and cooperation between national and provincial/prefectural-level CDCs,and deepen scientific and programmatic capacity of the National Immunization Program and provincial/prefectural immunization programs.Initiated in September 2019.
