期刊文献+
共找到629篇文章
< 1 2 32 >
每页显示 20 50 100
Scientific Advances and Weather Services of the China Meteorological Administration’s National Forecasting Systems during the Beijing 2022 Winter Olympics
1
作者 Guo DENG Xueshun SHEN +23 位作者 Jun DU Jiandong GONG Hua TONG Liantang DENG Zhifang XU jing chen Jian SUN Yong WANG Jiangkai HU Jianjie WANG Mingxuan chen Huiling YUAN Yutao ZHANG Hongqi LI Yuanzhe WANG Li GAO Li SHENG Da LI Li LI Hao WANG Ying ZHAO Yinglin LI Zhili LIU Wenhua GUO 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第5期767-776,共10页
Since the Beijing 2022 Winter Olympics was the first Winter Olympics in history held in continental winter monsoon climate conditions across complex terrain areas,there is a deficiency of relevant research,operational... Since the Beijing 2022 Winter Olympics was the first Winter Olympics in history held in continental winter monsoon climate conditions across complex terrain areas,there is a deficiency of relevant research,operational techniques,and experience.This made providing meteorological services for this event particularly challenging.The China Meteorological Administration(CMA)Earth System Modeling and Prediction Centre,achieved breakthroughs in research on short-and medium-term deterministic and ensemble numerical predictions.Several key technologies crucial for precise winter weather services during the Winter Olympics were developed.A comprehensive framework,known as the Operational System for High-Precision Weather Forecasting for the Winter Olympics,was established.Some of these advancements represent the highest level of capabilities currently available in China.The meteorological service provided to the Beijing 2022 Games also exceeded previous Winter Olympic Games in both variety and quality.This included achievements such as the“100-meter level,minute level”downscaled spatiotemporal resolution and forecasts spanning 1 to 15 days.Around 30 new technologies and over 60 kinds of products that align with the requirements of the Winter Olympics Organizing Committee were developed,and many of these techniques have since been integrated into the CMA’s operational national forecasting systems.These accomplishments were facilitated by a dedicated weather forecasting and research initiative,in conjunction with the preexisting real-time operational forecasting systems of the CMA.This program represents one of the five subprograms of the WMO’s high-impact weather forecasting demonstration project(SMART2022),and continues to play an important role in their Regional Association(RA)II Research Development Project(Hangzhou RDP).Therefore,the research accomplishments and meteorological service experiences from this program will be carried forward into forthcoming highimpact weather forecasting activities.This article provides an overview and assessment of this program and the operational national forecasting systems. 展开更多
关键词 Beijing Winter Olympic Games CMA national forecasting system data assimilation ensemble forecast bias correction and downscaling machine learning-based fusion methods
下载PDF
Survey on the Demand for Elderly Care Services of Community Residents in Beijing and Analysis of Influencing Factors
2
作者 Yue Zhai Xianguo Bi +3 位作者 Weimin Liu Hong Wang Xinxin Zhang jing chen 《Journal of Clinical and Nursing Research》 2024年第4期79-87,共9页
Objective: To investigate the current situation of the demand for geriatric care services of community residents in Beijing and analyze the influencing factors to provide a reference basis for meeting the demand for d... Objective: To investigate the current situation of the demand for geriatric care services of community residents in Beijing and analyze the influencing factors to provide a reference basis for meeting the demand for diversified and professional geriatric care services. Methods: A self-made questionnaire was used to randomly survey 1558 elderly individuals at community health service centers in 8 urban districts where elderly care centers were planned to be built. The influencing factors of the different characteristics of elderly care service needs from three aspects were analyzed using a dichotomous logistic regression model: predisposing, enabling, and, need factors. Results: 69.7% of the elderly required home care services, 22.8% wanted to get care services at elderly care centers, 15.9% wanted to get care services at nursing homes, 12.3% required community care services, and 7.4% didn’t know where to access care services. 68.5% of the elderly required care services for disabilities/semi-disabilities, 58.0% for dementia, 54.7% for common diseases, 34.9% for rehabilitation training, 33.0% for plumbing care, and 7.5% for hospice care. At the same time, there were urban- rural differences in the demand for elderly care services, with suburban elderly having a higher demand for care services than those living in urban areas (P < 0.05). The elderly’s demand for care services was mainly related to age, place of residence, and gender in the causative factors, mode of residence and physical condition among able factors, and mode of care services and care needs among need factors (P < 0.05). Conclusion: The demand for elderly care services was differentiated by factors including place of residence, age, and gender. It is crucial to accurately match the demand for elderly care services, innovate the mode of elderly care services, and improve the service quality to improve the elderly health service system. 展开更多
关键词 Elderly care Service system DEMAND Population ageing Influencing factors
下载PDF
数字技术赋能与协同治理网络:基于J市环境治理实践的分析
3
作者 陈静 黄萃 苏竣 《公共行政评论》 北大核心 2024年第4期55-72,M0004,M0005,共20页
随着大数据、人工智能等数字技术的快速发展和在治理实践中的广泛应用,治理主体创造和获取数据信息的方式,以及主体间协调与合作的过程等正在发生变化,其中蕴含的一个重要问题是数字技术赋能对多元主体开展协同治理会产生什么影响。论... 随着大数据、人工智能等数字技术的快速发展和在治理实践中的广泛应用,治理主体创造和获取数据信息的方式,以及主体间协调与合作的过程等正在发生变化,其中蕴含的一个重要问题是数字技术赋能对多元主体开展协同治理会产生什么影响。论文基于J市环境治理实践,采取社会网络分析和田野调查方法,从权力关系结构和合作关系结构两个维度对数字技术赋能下的协同治理网络变化进行了实证检验。研究发现,数字技术赋能提升了行动主体治理能力和领导势能,推动协同治理网络权力关系结构发生了变化,并通过信息整合共享、创新合作模式、强化对环境治理工作的激励与监督等方式,对多元主体间协同过程产生影响,进而推动了协同治理网络合作关系结构发生变化。研究有助于丰富和拓展数字技术赋能协同治理的研究视角和理论内涵,从而对深入理解数字技术在治理体系和治理能力中的重要作用具有理论和实践的指导意义。 展开更多
关键词 技术赋能 治理网络 权力关系结构 合作关系结构
下载PDF
Biomaterials and tissue engineering in traumatic brain injury:novel perspectives on promoting neural regeneration 被引量:2
4
作者 Shihong Zhu Xiaoyin Liu +7 位作者 Xiyue Lu Qiang Liao Huiyang Luo Yuan Tian Xu cheng Yaxin Jiang Guangdi Liu jing chen 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第10期2157-2174,共18页
Traumatic brain injury is a serious medical condition that can be attributed to falls, motor vehicle accidents, sports injuries and acts of violence, causing a series of neural injuries and neuropsychiatric symptoms. ... Traumatic brain injury is a serious medical condition that can be attributed to falls, motor vehicle accidents, sports injuries and acts of violence, causing a series of neural injuries and neuropsychiatric symptoms. However, limited accessibility to the injury sites, complicated histological and anatomical structure, intricate cellular and extracellular milieu, lack of regenerative capacity in the native cells, vast variety of damage routes, and the insufficient time available for treatment have restricted the widespread application of several therapeutic methods in cases of central nervous system injury. Tissue engineering and regenerative medicine have emerged as innovative approaches in the field of nerve regeneration. By combining biomaterials, stem cells, and growth factors, these approaches have provided a platform for developing effective treatments for neural injuries, which can offer the potential to restore neural function, improve patient outcomes, and reduce the need for drugs and invasive surgical procedures. Biomaterials have shown advantages in promoting neural development, inhibiting glial scar formation, and providing a suitable biomimetic neural microenvironment, which makes their application promising in the field of neural regeneration. For instance, bioactive scaffolds loaded with stem cells can provide a biocompatible and biodegradable milieu. Furthermore, stem cells-derived exosomes combine the advantages of stem cells, avoid the risk of immune rejection, cooperate with biomaterials to enhance their biological functions, and exert stable functions, thereby inducing angiogenesis and neural regeneration in patients with traumatic brain injury and promoting the recovery of brain function. Unfortunately, biomaterials have shown positive effects in the laboratory, but when similar materials are used in clinical studies of human central nervous system regeneration, their efficacy is unsatisfactory. Here, we review the characteristics and properties of various bioactive materials, followed by the introduction of applications based on biochemistry and cell molecules, and discuss the emerging role of biomaterials in promoting neural regeneration. Further, we summarize the adaptive biomaterials infused with exosomes produced from stem cells and stem cells themselves for the treatment of traumatic brain injury. Finally, we present the main limitations of biomaterials for the treatment of traumatic brain injury and offer insights into their future potential. 展开更多
关键词 bioactive materials BIOMATERIALS EXOSOMES neural regeneration scaffolds stem cells tissue engineering traumatic brain injury
下载PDF
Toward understanding the microstructure characteristics,phase selection and magnetic properties of laser additive manufactured Nd-Fe-B permanent magnets 被引量:1
5
作者 Bo Yao Nan Kang +6 位作者 Xiangyu Li Dou Li Mohamed EL Mansori jing chen Haiou Yang Hua Tan Xin Lin 《International Journal of Extreme Manufacturing》 SCIE EI CAS CSCD 2024年第1期277-294,共18页
Nd-Fe-B permanent magnets play a crucial role in energy conversion and electronic devices.The essential magnetic properties of Nd-Fe-B magnets,particularly coercivity and remanent magnetization,are significantly infue... Nd-Fe-B permanent magnets play a crucial role in energy conversion and electronic devices.The essential magnetic properties of Nd-Fe-B magnets,particularly coercivity and remanent magnetization,are significantly infuenced by the phase characteristics and microstructure.In this work,Nd-Fe-B magnets were manufactured using vacuum induction melting(VIM),laser directed energy deposition(LDED)and laser powder bed fusion(LPBF)technologies.Themicrostructure evolution and phase selection of Nd-Fe-B magnets were then clarified in detail.The results indicated that the solidification velocity(V)and cooling rate(R)are key factors in the phase selection.In terms of the VIM-casting Nd-Fe-B magnet,a large volume fraction of theα-Fe soft magnetic phase(39.7 vol.%)and Nd2Fe17Bxmetastable phase(34.7 vol.%)areformed due to the low R(2.3×10-1?C s-1),whereas only a minor fraction of the Nd2Fe14B hard magnetic phase(5.15 vol.%)is presented.For the LDED-processed Nd-Fe-B deposit,although the Nd2Fe14B hard magnetic phase also had a low value(3.4 vol.%)as the values of V(<10-2m s-1)and R(5.06×103?C s-1)increased,part of theα-Fe soft magnetic phase(31.7vol.%)is suppressed,and a higher volume of Nd2Fe17Bxmetastable phases(47.5 vol.%)areformed.As a result,both the VIM-casting and LDED-processed Nd-Fe-B deposits exhibited poor magnetic properties.In contrast,employing the high values of V(>10-2m s-1)and R(1.45×106?C s-1)in the LPBF process resulted in the substantial formation of the Nd2Fe14B hard magnetic phase(55.8 vol.%)directly from the liquid,while theα-Fe soft magnetic phase and Nd2Fe17Bxmetastable phase precipitation are suppressed in the LPBF-processed Nd-Fe-B magnet.Additionally,crystallographic texture analysis reveals that the LPBF-processedNd-Fe-B magnets exhibit isotropic magnetic characteristics.Consequently,the LPBF-processed Nd-Fe-B deposit,exhibiting a coercivity of 656 k A m-1,remanence of 0.79 T and maximum energy product of 71.5 k J m-3,achieved an acceptable magnetic performance,comparable to other additive manufacturing processed Nd-Fe-B magnets from MQP(Nd-lean)Nd-Fe-Bpowder. 展开更多
关键词 laser additive manufacturing(LAM) Nd-Fe-B permanent magnets numerical simulation microstructure magnetic properties
下载PDF
莫匹罗星软膏联合新癀片贴敷应用于化疗药物皮下注射所致皮肤损害的临床研究
6
作者 陈静 丁菊香 《生命科学仪器》 2024年第3期50-52,共3页
目的观察分析莫匹罗星软膏联合新癀片贴敷对化疗药物皮下注射所致皮肤损害的影响。方法选取2023年10月至2024年3月医院收治的恶性血液病患者70例为研究对象,将其随机分为两组,对照组(35例)对常规注射部位采用湿热敷,观察组(35例)对常规... 目的观察分析莫匹罗星软膏联合新癀片贴敷对化疗药物皮下注射所致皮肤损害的影响。方法选取2023年10月至2024年3月医院收治的恶性血液病患者70例为研究对象,将其随机分为两组,对照组(35例)对常规注射部位采用湿热敷,观察组(35例)对常规注射部位给予莫匹罗星软膏联合新癀片贴敷。对比两组临床效果、治疗后疼痛发生率、敷药依从性及护理满意度。结果观察组总有效率高于对照组,P<0.05;观察组干预后敷药总依从率、护理满意度均高于对照组,P<0.05;观察组干预后疼痛发生率低于对照组,P<0.05。结论用莫匹罗星软膏联合新癀片贴敷治疗化疗药物皮下注射所致皮肤损害,不仅能增强治疗效果,减轻疼痛程度,还能提高患者敷药依从性和护理满意度。 展开更多
关键词 莫匹罗星软膏 新癀片 化疗药物 皮下注射 皮肤损害 贴敷治疗
下载PDF
Investigation on photonic crystal nanobeam cavity based on mixed diamond–circular holes
7
作者 jingtong Bin Kerui Feng +4 位作者 Shang Ma Ke Liu Yong cheng jing chen Qifa Liu 《Nanotechnology and Precision Engineering》 EI CAS CSCD 2024年第1期63-70,共8页
A photonic crystal nanobeam cavity(M-PCNC)with a structure incorporating a mixture of diamond-shaped and circular air holes is pro-posed.The performance of the cavity is simulated and studied theoretically.Using thefin... A photonic crystal nanobeam cavity(M-PCNC)with a structure incorporating a mixture of diamond-shaped and circular air holes is pro-posed.The performance of the cavity is simulated and studied theoretically.Using thefinite-difference time-domain method,the parameters of the M-PCNC,including cavity thickness and width,lattice constant,and radii and numbers of holes,are optimized,with the quality factor Q and mode volume Vm as performance indicators.Mutual modulation of the lattice constant and hole radius enable the proposed M-PCNC to realize outstanding performance.The optimized cavity possesses a high quality factor Q 1.45105 and an ultra-small mode=×volume Vm 0.01(λ/n)[Zeng et al.,Opt Lett 2023:48;3981–3984]in the telecommunications wavelength range.Light can be progres-=sively squeezed in both the propagation direction and the perpendicular in-plane direction by a series of interlocked anti-slots and slots in the diamond-shaped hole structure.Thereby,the energy can be confined within a small mode volume to achieve an ultra-high Q/Vm ratio. 展开更多
关键词 Photonic crystal nanobeam cavity Mixed diamond–circular holes Slots and anti-slots FDTD simulation Quality factor Mode volume
下载PDF
Homozygous CCDC146 mutation causes oligoasthenoteratozoospermia in humans and mice
8
作者 jing-Wei Ye Tanveer Abbas +10 位作者 Jian-Teng Zhou jing chen Meng-Lei Yang Xiong-Heng Huang Huan Zhang Hui Ma Ao Ma Bo Xu Ghulam Murtaza Qing-Hua Shi Bao-Lu Shi 《Zoological Research》 SCIE CSCD 2024年第5期1073-1087,共15页
Infertility represents a significant health concern,with sperm quantity and quality being crucial determinants of male fertility.Oligoasthenoteratozoospermia(OAT)is characterized by reduced sperm motility,lower sperm ... Infertility represents a significant health concern,with sperm quantity and quality being crucial determinants of male fertility.Oligoasthenoteratozoospermia(OAT)is characterized by reduced sperm motility,lower sperm concentration,and morphological abnormalities in sperm heads and flagella.Although variants in several genes have been implicated in OAT,its genetic etiologies and pathogenetic mechanisms remain inadequately understood.In this study,we identified a homozygous nonsense mutation(c.916C>T,p.Arg306*)in the coiled-coil domain containing 146(CCDC146)gene in an infertile male patient with OAT.This mutation resulted in the production of a truncated CCDC146 protein(amino acids 1-305),retaining only two out of five coiled-coil domains.To validate the pathogenicity of the CCDC146 mutation,we generated a mouse model(Ccdc146^(mut/mut))with a similar mutation to that of the patient.Consistently,the Ccdc146mut/mut mice exhibited infertility,characterized by significantly reduced sperm counts,diminished motility,and multiple defects in sperm heads and flagella.Furthermore,the levels of axonemal proteins,including DNAH17,DNAH1,and SPAG6,were significantly reduced in the sperm of Ccdc146^(mut/mut) mice.Additionally,both human and mouse CCDC146 interacted with intraflagellar transport protein 20(IFT20),but this interaction was lost in the mutated versions,leading to the degradation of IFT20.This study identified a novel deleterious homozygous nonsense mutation in CCDC146 that causes male infertility,potentially by disrupting axonemal protein transportation.These findings offer valuable insights for genetic counseling and understanding the mechanisms underlying CCDC146 mutant-associated infertility in human males. 展开更多
关键词 OLIGOASTHENOTERATOZOOSPERMIA Human infertility Sperm flagellum CCDC146 Intraflagellar transport IFT20
下载PDF
Performance Limits and Advancements in Single 2D Transition Metal Dichalcogenide Transistor
9
作者 jing chen Ming-Yuan Sun +8 位作者 Zhen-Hua Wang Zheng Zhang Kai Zhang Shuai Wang Yu Zhang Xiaoming Wu Tian-Ling Ren Hong Liu Lin Han 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第12期134-188,共55页
Two-dimensional(2D)transition metal dichalcogenides(TMDs)allow for atomic-scale manipulation,challenging the conventional limitations of semiconductor materials.This capability may overcome the short-channel effect,sp... Two-dimensional(2D)transition metal dichalcogenides(TMDs)allow for atomic-scale manipulation,challenging the conventional limitations of semiconductor materials.This capability may overcome the short-channel effect,sparking significant advancements in electronic devices that utilize 2D TMDs.Exploring the dimension and performance limits of transistors based on 2D TMDs has gained substantial importance.This review provides a comprehensive investigation into these limits of the single 2D-TMD transistor.It delves into the impacts of miniaturization,including the reduction of channel length,gate length,source/drain contact length,and dielectric thickness on transistor operation and performance.In addition,this review provides a detailed analysis of performance parameters such as source/drain contact resistance,subthreshold swing,hysteresis loop,carrier mobility,on/off ratio,and the development of p-type and single logic transistors.This review details the two logical expressions of the single 2D-TMD logic transistor,including current and voltage.It also emphasizes the role of 2D TMD-based transistors as memory devices,focusing on enhancing memory operation speed,endurance,data retention,and extinction ratio,as well as reducing energy consumption in memory devices functioning as artificial synapses.This review demonstrates the two calculating methods for dynamic energy consumption of 2D synaptic devices.This review not only summarizes the current state of the art in this field but also highlights potential future research directions and applications.It underscores the anticipated challenges,opportunities,and potential solutions in navigating the dimension and performance boundaries of 2D transistors. 展开更多
关键词 Two-dimensional transistors Dimension limits Performance limits Memory devices Artificial synapses
下载PDF
Customization of FeNi alloy nanosheet arrays inserted with biomass-derived carbon templates for boosted electromagnetic wave absorption
10
作者 Xuanqi Yang Honghan Wang +5 位作者 jing chen Qingda An Zuoyi Xiao jingai Hao Shangru Zhai Junye Sheng 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第4期812-824,共13页
Electromagnetic wave(EMW)-absorbing materials have considerable capacity in the military field and the prevention of EMW radiation from harming human health.However,obtaining lightweight,high-performance,and broadband... Electromagnetic wave(EMW)-absorbing materials have considerable capacity in the military field and the prevention of EMW radiation from harming human health.However,obtaining lightweight,high-performance,and broadband EMW-absorbing material remains an overwhelming challenge.Creating dielectric/magnetic composites with customized structures is a strategy with great promise for the development of high-performance EMW-absorbing materials.Using layered double hydroxides as the precursors of bimetallic alloys and combining them with porous biomass-derived carbon materials is a potential way for constructing multi-interface heterostructures as efficient EMW-absorbing materials because they have synergistic losses,low costs,abundant resources,and light weights.Here,FeNi alloy nanosheet array/Lycopodium spore-derived carbon(FeNi/LSC)was prepared through a simple hydrothermal and carbonization method.FeNi/LSC presents ideal EMW-absorbing performance by benefiting from the FeNi alloy nanosheet array,sponge-like structure,capability for impedance matching,and improved dielectric/magnetic losses.As expected,FeNi/LSC exhibited the minimum reflection loss of-58.3 dB at 1.5 mm with 20wt%filler content and a widely effective absorption bandwidth of 4.92 GHz.FeNi/LSC composites with effective EMW-absorbing performance provide new insights into the customization of biomass-derived composites as high-performance and lightweight broadband EMW-absorbing materials. 展开更多
关键词 spore-derived carbon FeNi alloy nanosheet array multi-interface heterostructures synergistic effect efficient electromagnet-ic wave absorption
下载PDF
Design of hadronic calorimeter for DarkSHINE experiment
11
作者 Zhen Wang Rui Yuan +18 位作者 Han-Qing Liu jing chen Xiang chen Kim Siang Khaw Liang Li Shu Li Kun Liu Qi-Bin Liu Si-Yuan Song Tong Sun Xiao-Long Wang Yu-Feng Wang Hai-Jun Yang Jun-Hua Zhang Yu-Lei Zhang Zhi-Yu Zhao Chun-Xiang Zhu Xu-Liang Zhu Yi-Fan Zhu 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第9期155-167,共13页
The sensitivity of the dark photon search through invisible decay final states in low-background experiments relies sig-nificantly on the neutron and muon veto efficiencies,which depend on the amount of material used ... The sensitivity of the dark photon search through invisible decay final states in low-background experiments relies sig-nificantly on the neutron and muon veto efficiencies,which depend on the amount of material used and the design of the detector geometry.This paper presents the optimized design of the hadronic calorimeter(HCAL)used in the DarkSHINE experiment,which is studied using a GEANT4-based simulation framework.The geometry is optimized by comparing a traditional design with uniform absorbers to one that uses different thicknesses at different locations on the detector,which enhances the efficiency of vetoing low-energy neutrons at the sub-GeV level.The overall size and total amount of material used in the HCAL are optimized to be lower,owing to the load and budget requirements,whereas the overall performance is studied to satisfy the physical objectives. 展开更多
关键词 Hadronic calorimeter GEANT4 simulation Neutron background Scintillation detector Dark photon
下载PDF
Research on the Reform of the Process-Tracking Ideological and Political Assessment System in Applied Universities:Taking the Personal Finance Course as an Example 被引量:1
12
作者 jing chen 《Journal of Contemporary Educational Research》 2024年第1期179-185,共7页
Using the Xi’an Mingde Institute of Technology students as the teaching object and the Personal Finance course as an example,we explore the reform of the ideological and political assessment system of process-trackin... Using the Xi’an Mingde Institute of Technology students as the teaching object and the Personal Finance course as an example,we explore the reform of the ideological and political assessment system of process-tracking courses in applied universities.The article analyzes the feasibility of applying the curriculum ideological and political assessment system in college courses and compares the traditional assessment system.It also proposes that applying curriculum ideological and political assessment to the college curriculum assessment system will help improve students’understanding of the“value guidance”in curriculum ideological and political education and enhance the teaching effect. 展开更多
关键词 Curriculum ideological and political education Teaching reform Curriculum assessment
下载PDF
Success of susceptibility-guided eradication of Helicobacter pylori in a region with high secondary clarithromycin and levofloxacin resistance rates
13
作者 Yan-Meng Wang Mo-Ye chen +4 位作者 jing chen Xin-He Zhang Yan Feng Yu-Xi Han Yi-Ling Li 《World Journal of Gastroenterology》 SCIE CAS 2024年第2期184-195,共12页
BACKGROUND Resistance to clarithromycin(CLA)and levofloxacin(LFX)of Helicobacter pylori(H.pylori)is increasing in severity,and successful eradication is essential.Presently,the eradication success rate has greatly dec... BACKGROUND Resistance to clarithromycin(CLA)and levofloxacin(LFX)of Helicobacter pylori(H.pylori)is increasing in severity,and successful eradication is essential.Presently,the eradication success rate has greatly declined,leaving a large number of patients with previous treatment histories.AIM To investigate secondary resistance rates,explore risk factors for antibiotic resistance,and assess the efficacy of susceptibility-guided therapy.METHODS We recruited 154 subjects positive for Urea Breath Test who attended The First Affiliated Hospital of China Medical University between July 2022 and April 2023.Participants underwent a string test after an overnight fast.The gastric juice was obtained and transferred to vials containing storage solution.Subsequently,DNA extraction and the specific DNA amplification were performed using quantitative polymerase chain reaction(qPCR).Demographic information was also analyzed as part of the study.Based on these results,the participants were administered susceptibility-guided treatment.Efficacy was compared with that of the empiric treatment group.RESULTS A total of 132 individuals tested positive for the H.pylori ureA gene by qPCR technique.CLA resistance rate reached a high level of 82.6%(n=109),LFX resistance rate was 69.7%(n=92)and dual resistance was 62.1%(n=82).Gastric symptoms[odds ratio(OR)=2.782;95%confidence interval(95%CI):1.076-7.194;P=0.035]and rural residence(OR=5.152;95%CI:1.407-18.861;P=0.013)were independent risk factors for secondary resistance to CLA and LFX,respectively.A total of 102 and 100 individuals received susceptibility-guided therapies and empiric treatment,respectively.The antibiotic susceptibility-guided treatment and empiric treatment groups achieved successful eradication rates of 75.5%(77/102)and 59.0%(59/411)by the intention-to-treat(ITT)analysis and 90.6%(77/85)and 70.2%(59/84)by the per-protocol(PP)analysis,respectively.The eradication rates of these two treatment strategies were significantly different in both ITT(P=0.001)and PP(P=0.012)analyses.CONCLUSION H.pylori presented high secondary resistance rates to CLA and LFX.For patients with previous treatment failures,treatments should be guided by antibiotic susceptibility tests or regional antibiotic resistance profile. 展开更多
关键词 Helicobacter pylori Antibiotic resistance CLARITHROMYCIN LEVOFLOXACIN String-test Susceptibility-guided therapy Eradication rate
下载PDF
The environment,especially the minimum temperature,affects summer maize grain yield by regulating ear differentiation and grain development
14
作者 jing chen Baizhao Ren +2 位作者 Bin Zhao Peng Liu Jiwang Zhang 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第7期2227-2241,共15页
Ear differentiation,grain development and their interaction with factors in the growing environment,such as temperature,solar radiation and precipitation,greatly influence grain number and grain weight,and ultimately ... Ear differentiation,grain development and their interaction with factors in the growing environment,such as temperature,solar radiation and precipitation,greatly influence grain number and grain weight,and ultimately affect summer maize production.In this study,field experiments involving different sowing dates were conducted over three years to evaluate the effects of temperature factors,average solar radiation and total precipitation on the growth process,ear differentiation,fertilization characteristics,grain filling and yield of summer maize varieties with different growth durations.Four hybrids were evaluated in Huang-Huai-Hai Plain(HHHP),China from 2018 to 2020 with five different sowing dates.The results showed that the grain yield formation of summer maize was strongly impacted by the environment from the silking(R1)to milking(R3)stage.Average minimum temperature(AT_(min))was the key environmental factor that determined yield.Reductions in the length of the growing season(r=–0.556,P<0.01)and the total floret number on ear(R^(2)=0.200,P<0.001)were found when AT_(min) was elevated from the emerging(VE)to R1 stage.Both grain-filling rate(R^(2)=0.520,P<0.001)and the floret abortion rate on ear(R^(2)=0.437,P<0.001)showed quadratic relationships with AT_(min) from the R1 to physiological maturity(R6)stage,while the number of days after the R1 stage(r=–0.756,P<0.01)was negatively correlated with AT_(min).An increase in AT_(min) was beneficial for the promotion of yield when it did not exceeded a certain level(above 23°C during the R1–R3 stage and 20–21°C during the R1-R6 stage).Enhanced solar radiation and precipitation during R1–R6 increased the grain-filling rate(R^(2)=0.562,P<0.001 and R^(2)=0.229,P<0.05,respectively).Compared with short-season hybrids,full-season hybrids showed much greater suitability for a critical environment.The coordinated regulation of AT_(min),ear differentiation and grain development at the pre-and post-silking stages improved maize yield by increasing total floret number and grain-filling rate,and by reducing the floret abortion rate on ear. 展开更多
关键词 sowing date hybrid maturity growing environment ear differentiation and grain development
下载PDF
Time-energy distribution of photoelectron from atomic states with different magnetic quantum numbers in elliptically polarized laser fields
15
作者 jingyang Xu Li Guo +4 位作者 Xin Qi Ronghua Lu Min Zhang jingtao Zhang jing chen 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第9期374-382,共9页
A Wigner-distribution-like(WDL)function based on the strong-field approximation(SFA)theory is used to investigate the ionization time of the photoelectron emitted from the initial states with different magnetic quantu... A Wigner-distribution-like(WDL)function based on the strong-field approximation(SFA)theory is used to investigate the ionization time of the photoelectron emitted from the initial states with different magnetic quantum number m in elliptically polarized electric fields.The saddle-point method is adopted for comparisons.For different m states,a discrepancy exists in the WDL distributions of the photoelectrons emitted in a direction close to the major axis of the laser field ellipse.Based on the saddle-point analysis,this discrepancy can be ascribed to the interference between electrons ionized from two tunneling instants.Our results show that the relationships between the tunneling instants and kinetic energy of photoelectrons are the same for different m initial states when the Coulomb potential is not considered.Our work sheds some light on the ionization-time information of electrons from different magnetic quantum states. 展开更多
关键词 strong-field IONIZATION Wigner-distribution-like IONIZATION INSTANT
下载PDF
An Initial Perturbation Method for the Multiscale Singular Vector in Global Ensemble Prediction
16
作者 Xin LIU jing chen +6 位作者 Yongzhu LIU Zhenhua HUO Zhizhen XU Fajing chen jing WANG Yanan MA Yumeng HAN 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第3期545-563,共19页
Ensemble prediction is widely used to represent the uncertainty of single deterministic Numerical Weather Prediction(NWP) caused by errors in initial conditions(ICs). The traditional Singular Vector(SV) initial pertur... Ensemble prediction is widely used to represent the uncertainty of single deterministic Numerical Weather Prediction(NWP) caused by errors in initial conditions(ICs). The traditional Singular Vector(SV) initial perturbation method tends only to capture synoptic scale initial uncertainty rather than mesoscale uncertainty in global ensemble prediction. To address this issue, a multiscale SV initial perturbation method based on the China Meteorological Administration Global Ensemble Prediction System(CMA-GEPS) is proposed to quantify multiscale initial uncertainty. The multiscale SV initial perturbation approach entails calculating multiscale SVs at different resolutions with multiple linearized physical processes to capture fast-growing perturbations from mesoscale to synoptic scale in target areas and combining these SVs by using a Gaussian sampling method with amplitude coefficients to generate initial perturbations. Following that, the energy norm,energy spectrum, and structure of multiscale SVs and their impact on GEPS are analyzed based on a batch experiment in different seasons. The results show that the multiscale SV initial perturbations can possess more energy and capture more mesoscale uncertainties than the traditional single-SV method. Meanwhile, multiscale SV initial perturbations can reflect the strongest dynamical instability in target areas. Their performances in global ensemble prediction when compared to single-scale SVs are shown to(i) improve the relationship between the ensemble spread and the root-mean-square error and(ii) provide a better probability forecast skill for atmospheric circulation during the late forecast period and for short-to medium-range precipitation. This study provides scientific evidence and application foundations for the design and development of a multiscale SV initial perturbation method for the GEPS. 展开更多
关键词 multiscale uncertainty singular vector initial perturbation global ensemble prediction system
下载PDF
Effects of cold rolling path on recrystallization behavior and mechanical properties of pure copper during annealing
17
作者 jing chen Wen-jie XU +8 位作者 Jia-hao YANG Zhi YANG Hong-li SHI Gao-yong LIN Zhu-min LI Xu SHEN Bo JIANG Hui-qun LIU Kai-xuan GUI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第10期3233-3250,共18页
The recrystallization behavior,grain boundary characteristic distribution,and mechanical properties of pure Cu sheets that were subjected to different cold rolling paths,and then annealed at 400°C for 10,30,60,an... The recrystallization behavior,grain boundary characteristic distribution,and mechanical properties of pure Cu sheets that were subjected to different cold rolling paths,and then annealed at 400°C for 10,30,60,and 420 min,were investigated.Different rolling paths changed the grain boundary orientations of cold-rolled copper,causing recrystallized grains to nucleate and grow in an oriented manner.However,the evolution of the texture indicated that cold-rolled copper with different rolling paths did not show an obvious preferred orientation after annealing.The RD-60 specimen exhibited the smallest grain size(6.6μm).The results indicated that the grain size and low-ΣCSL grain boundaries worked together to provide RD-60 samples with appropriate mechanical properties and high plasticity.The yield strength,ultimate tensile strength,and elongation of RD-60 sample were 81 MPa,230 MPa,and 49%,respectively.These results could provide guidance for tuning the microstructures and properties of pure Cu foils,as well as designing fabrication routes for pure Cu foils through processes such as rolling and drawing. 展开更多
关键词 rolling path grain boundary characteristic distribution pure copper mechanical properties
下载PDF
Review of the SiC LDMOS power device
18
作者 Ziwei Hu Jiafei Yao +7 位作者 Ang Li Qi Sun Man Li Kemeng Yang Jun Zhang jing chen Maolin Zhang Yufeng Guo 《Journal of Semiconductors》 EI CAS CSCD 2024年第8期4-17,共14页
Silicon carbide(SiC),as a third-generation semiconductor material,possesses exceptional material properties that significantly enhance the performance of power devices.The SiC lateral double-diffused metal–oxide–sem... Silicon carbide(SiC),as a third-generation semiconductor material,possesses exceptional material properties that significantly enhance the performance of power devices.The SiC lateral double-diffused metal–oxide–semiconductor(LDMOS)power devices have undergone continuous optimization,resulting in an increase in breakdown voltage(BV)and ultra-low specific on-resistance(Ron,sp).This paper has summarized the structural optimizations and experimental progress of SiC LDMOS power devices,including the trench-gate technology,reduced surface field(RESURF)technology,doping technology,junction termination techniques and so on.The paper is aimed at enhancing the understanding of the operational mechanisms and providing guidelines for the further development of SiC LDMOS power devices. 展开更多
关键词 SIC LDMOS specific on-resistance breakdown voltage
下载PDF
Synergy of inside doped metals–Outside coated graphene to enhance hydrogen storage in magnesium-based alloys
19
作者 Kun Zhang Yu Chang +7 位作者 jingjing Lei jing chen Tingzhi Si Xiaoli Ding Ping Cui Hai-Wen Li Qingan Zhang Yongtao Li 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第6期2462-2471,共10页
Grain growth of magnesium(Mg)and its hydride is one of the main reasons for kinetic and capacity degradation during the hydrogen absorption and desorption cycles.To solve this problem,herein we propose a novel method ... Grain growth of magnesium(Mg)and its hydride is one of the main reasons for kinetic and capacity degradation during the hydrogen absorption and desorption cycles.To solve this problem,herein we propose a novel method involving synergistic effect of inside embedded metals and outside coated graphene to limit the growth of Mg and its hydride grains.The graphene coated Mg-Y-Al alloys were selected as a model system for demonstrating this positive effect where the Mg_(91)Y_(3)Al_(6)alloy was first prepared by rapidly solidified method and then high-pressure milled with 5 wt%graphene upon 5 MPa hydrogen gas for obtaining in-situ formed YAl_(2)and YH_(3)embedded in the MgH_(2)matrix with graphene shell(denoted as MgH_(2)-Y-Al@GR).In comparison to pure MgH_(2),the obtained MgH_(2)-Y-Al@GR composites deliver much better kinetics and more stable cyclic performance.For instance,the MgH_(2)-Y-Al@GR can release about 6.1 wt%H_(2)within 30 min at 300℃ but pure MgH_(2)only desorbs∼1.5 wt%H_(2).The activation energy for desorption of MgH_(2)-Y-Al@GR samples is calculated to be 75.3±9.1 kJ/mol that is much lower than approximately 160 kJ/mol for pure MgH_(2).Moreover,its capacity retention is promoted from∼57%of pure MgH_(2)to∼84%after 50th cycles without obvious particle agglomeration and grain growth.The synergistic effect of outside graphene coating with inside embedded metals which could provide a huge number of active sites for catalysis as well as inhibit the grain growth of Mg and its hydride is believed to be responsible for these. 展开更多
关键词 Energy Hydrogen storage Mg alloys Synergy effect
下载PDF
Application of exosomal miRNA mediated macrophage polarization in colorectal cancer:Current progress and challenges
20
作者 YUN ZHANG SHALING TANG +4 位作者 YUBO GAO ZHONGTING LU YUAN YANG jing chen TAO LI 《Oncology Research》 SCIE 2024年第1期61-71,共11页
Colorectal cancer(CRC)is a major global health problem with high morbidity and mortality rates.Surgical resection is the main treatment for early-stage CRC,but detecting it early is challenging.Therefore,effective the... Colorectal cancer(CRC)is a major global health problem with high morbidity and mortality rates.Surgical resection is the main treatment for early-stage CRC,but detecting it early is challenging.Therefore,effective therapeutic targets for advanced patients are still lacking.Exosomes,tiny vesicles in body fluids,play a crucial role in tumor metastasis,immune regulation,and drug resistance.Interestingly,they can even serve as a biomarker for cancer diagnosis and prognosis.Studies have shown that exosomes can carry miRNA,mediate the polarization of M1/M2 macrophages,promote the proliferation and metastasis of cancer cells,and affect the prognosis of CRC.Since the gastrointestinal tract has many macrophages,understanding the mechanism behind exosomal miRNA-mediated macrophage polarization in CRC treatment is crucial.This article summarizes recent advancements in the study of exosomal miRNAs in CRC and their potential as diagnostic and prognostic markers. 展开更多
关键词 Colorectal cancer EXOSOMES MICRORNA MACROPHAGES Treatment
下载PDF
上一页 1 2 32 下一页 到第
使用帮助 返回顶部