Summary What is known about this topic?Few major outbreaks of coronavirus disease 2019(COVID-19)have occurred in China after major nonpharmaceutical interventions and vaccines have been deployed and implemented.Howeve...Summary What is known about this topic?Few major outbreaks of coronavirus disease 2019(COVID-19)have occurred in China after major nonpharmaceutical interventions and vaccines have been deployed and implemented.However,sporadic outbreaks that had high possibility to be linked to cold chain products were reported in several cities of China..What is added by this report?In July 2020,a COVID-19 outbreak occurred in Dalian,China.The investigations of this outbreak strongly suggested that the infection source was from COVID-19 virus-contaminated packaging of frozen seafood during inbound unloading personnel contact.What are the implications for public health practice?Virus contaminated paper surfaces could maintain infectivity for at least 17–24 days at-25℃.Exposure to COVID-19 virus-contaminated surfaces is a potential route for introducing the virus to a susceptible population.Countries with no domestic transmission of COVID-19 should consider introducing prevention strategies for both inbound travellers and imported goods.Several measures to prevent the introduction of the virus via cold-chain goods can be implemented.展开更多
目的:探讨补骨合剂协定方联合功能锻炼改善退行性腰椎管狭窄症患者腰椎功能的临床效果及对椎管内血液微循环、微炎状态的影响。方法:选取2017年2月至2018年5月中南大学湘雅医学院附属海口医院收治的退行性腰椎管狭窄症(气虚血瘀证)患者...目的:探讨补骨合剂协定方联合功能锻炼改善退行性腰椎管狭窄症患者腰椎功能的临床效果及对椎管内血液微循环、微炎状态的影响。方法:选取2017年2月至2018年5月中南大学湘雅医学院附属海口医院收治的退行性腰椎管狭窄症(气虚血瘀证)患者118例作为研究对象,随机分为对照组和观察组,每组59例。对照组患者给予氨糖美辛肠溶片联合功能锻炼治疗,观察组患者在对照组治疗的基础上给予补骨合剂协定方内服治疗,比较2组治疗的临床效果,观察患者治疗前后腰椎功能、腰椎疼痛程度及腰痛对日常生活能力的影响情况,测定患者的血液流变学指标,检测血清肿瘤坏死因子-α(TNF-α)、白细胞介素-1α(IL-1α)、单核细胞趋化蛋白-1(Monocyte Chemotactic Protein-1,MCP-1)、降钙素原(procalcitonin,PCT)水平。结果:对照组有效率为74.6%,明显低于观察组有效率91.5%,差异有统计学意义( P <0.05);治疗后,观察组的腰椎功能JOA评分较对照组升高明显,疼痛视觉模拟评分(VAS),Oswestry功能障碍指数(ODI)评分则较对照组更低,差异有统计学意义( P <0.05);观察组的血液流变学指标改善更明显,其全血黏度、血浆黏度、血细胞比容、纤维蛋白原均低于对照组,差异有统计学意义( P <0.05);观察组的机体微炎状态改善更明显,其TNF-α、IL-1α、MCP-1、PCT等炎性反应递质水平明显低于对照组,差异有统计学意义( P <0.05)。结论:加用补骨合剂协定方联合功能锻炼利于提高腰椎功能,减轻腰椎疼痛,提高日常生活能力。展开更多
Research on two-dimensional(2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since ...Research on two-dimensional(2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since the mechanical exfoliation of graphene in 2004. Starting from graphene, 2D materials now have become a big family with numerous members and diverse categories. The unique structural features and physicochemical properties of 2D materials make them one class of the most appealing candidates for a wide range of potential applications. In particular, we have seen some major breakthroughs made in the field of 2D materials in last five years not only in developing novel synthetic methods and exploring new structures/properties but also in identifying innovative applications and pushing forward commercialisation. In this review, we provide a critical summary on the recent progress made in the field of 2D materials with a particular focus on last five years. After a brief backgroundintroduction, we first discuss the major synthetic methods for 2D materials, including the mechanical exfoliation, liquid exfoliation, vapor phase deposition, and wet-chemical synthesis as well as phase engineering of 2D materials belonging to the field of phase engineering of nanomaterials(PEN). We then introduce the superconducting/optical/magnetic properties and chirality of 2D materials along with newly emerging magic angle 2D superlattices. Following that, the promising applications of 2D materials in electronics, optoelectronics, catalysis, energy storage, solar cells, biomedicine, sensors, environments, etc. are described sequentially. Thereafter, we present the theoretic calculations and simulations of 2D materials. Finally, after concluding the current progress, we provide some personal discussions on the existing challenges and future outlooks in this rapidly developing field.展开更多
The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 3...The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.展开更多
Blast-induced dominant vibration frequency （DVF） involves a complex, nonlinear and small sample system considering rock properties, blasting parameters and topography. In this study, a combination of grey relational...Blast-induced dominant vibration frequency （DVF） involves a complex, nonlinear and small sample system considering rock properties, blasting parameters and topography. In this study, a combination of grey relational analysis and dimensional analysis procedures for prediction of dominant vibration frequency are presented. Six factors are selected from extensive effect factor sequences based on grey relational analysis, and then a novel blast-induced dominant vibration frequency prediction is obtained by dimensional analysis. In addition, the prediction is simplified by sensitivity analysis with 195 experimental blast records. Validation is carried out for the proposed formula based on the site test database of the first- period blasting excavation in the Guangdong Lufeng Nuclear Power Plant （GLNPP）. The results show the proposed approach has a higher fitting degree and smaller mean error when compared with traditional predictions.展开更多
Research on CRISPR-Cas（clustered regularly interspaced short palindromic repeats-CRISPR associated protein） systems has led to the revolutionary CRISPR/Cas9 genome editing technique. However, for most archaea and ha...Research on CRISPR-Cas（clustered regularly interspaced short palindromic repeats-CRISPR associated protein） systems has led to the revolutionary CRISPR/Cas9 genome editing technique. However, for most archaea and half of bacteria, exploitation of their native CRISPR-Cas machineries may be more straightforward and convenient. In this study, we harnessed the native type I-B CRISPR-Cas system for precise genome editing in the polyploid haloarchaeon Haloarcula hispanica. After testing different designs, the editing tool was optimized to be a single plasmid that carries both the self-targeting miniCRISPR and a 600-800 bp donor. Significantly, chromosomal modifications, such as gene deletion, gene tagging or single nucleotide substitution, were precisely introduced into the vast majority of the transformants. Moreover, we showed that simultaneous editing of two genomic loci could also be readily achieved by one step. In summary, our data demonstrate that the haloarchaeal CRISPR-Cas system can be harnessed for genome editing in this polyploid archaeon, and highlight the convenience and efficiency of the native CRISPR-based genome editing strategy.展开更多
Ralstonia solanacearum, the causative agent of bacterial wilt, is a soil-borne pathogen that poses a widespread threat to plants in the Solanaceae family. To elucidate the mechanism by which limonene exerts its effect...Ralstonia solanacearum, the causative agent of bacterial wilt, is a soil-borne pathogen that poses a widespread threat to plants in the Solanaceae family. To elucidate the mechanism by which limonene exerts its effects on R. solanacearum, we first assessed the impact of limonene on the physiological indicators of the pathogen and subsequently analyzed its transcriptome and metabolome. Our findings indicate that limonene has a potent inhibitory effect on R. solanacearum, and it also suppresses the formation of the bacterial community biofilm. Limonene primarily regulates the terpene biosynthesis pathway in R. solanacearum, thereby potentially affecting signal transduction in the pathogen and disrupting its normal growth and development. These results significantly enhance our understanding of limonene’s response to the induction of bacterial wilt and provide a reference for further prevention and control of R. solanacearum.展开更多
Oligosaccharides are low molecular weight carbohydrates between monosaccharides and poly-saccharides,which consist of 2 to 20 monosaccharides linked by glycosidic bonds.They have the effects of promoting growth,regula...Oligosaccharides are low molecular weight carbohydrates between monosaccharides and poly-saccharides,which consist of 2 to 20 monosaccharides linked by glycosidic bonds.They have the effects of promoting growth,regulating immunity,improving the structure of intestinal flora,and are anti-inflammatory and antioxidant.With the comprehensive implementation of the antibiotic prohibition policy in China,oligosaccharides as new green feed additive have been paid more attention.Oligosac-charides can be divided into the following 2 categories according to their digestive characteristics:one is easy to be absorbed by the intestine,called common oligosaccharides,such as sucrose and maltose oligosaccharide;the other is difficult to be absorbed by the intestine and has special physiological functions,called functional oligosaccharides.The common functional oligosaccharides include mannan oligosaccharides(MOS),fructo-oligosaccharides(FOS),chitosan oligosaccharides(COS),xylo-oligosaccharides(XOS)and so on.In this paper,we review the types and sources of functional oligo-saccharides,their application in pig nutrition,and the factors limiting their efficacy in recent years.This review provides the theoretical basis for further research of functional oligosaccharides,and the future application of alternative antibiotics in pig industry.展开更多
In the process of blasting excavation, stress wave propagation and gas expansion can basically induce damage to surrounding rocks, which is detrimental to rock mass integrity and engineering safety. In this case, eval...In the process of blasting excavation, stress wave propagation and gas expansion can basically induce damage to surrounding rocks, which is detrimental to rock mass integrity and engineering safety. In this case, evaluation and control of blast-induced effects are essential to the safety of nearby buildings and integrity of bedrock in blasting field. In Fangchenggang nuclear power station of China, the drill-and- blast method was employed for bedrock excavation. In order to reduce the blast-induced damage zone, the wave propagation and associated damage to rock mass should be carefully investigated. In this paper, the wave propagation regressively obtained from field monitoring data was presented based on empirical formula （e.g. Sadovsloj formula）. The relationship between the peak particle velocity （PPV） at a distance of 30 m away from the charge hole and charge per delay in blast design was derived. Meanwhile, the acoustic tests before and after blasting were conducted to determine the damage depth of rock mass. The charge per delay in blast design was then calibrated based on the blast-induced wave propagation regularity. The results showed that a satisfactory effect was achieved on blast-induced damage control of rock mass. This could be helpful to rock damage control in similar blasting projects.展开更多
基金The National Key Research and Development Project,Ministry of Science and Technology of the People’s Republic of China(2021YFC0863000,2018ZX10713002,and 2020YFC0846900),National Natural Science Foundation of China(No.72042012,and No.82041032)and National Key Technology R&D Program of China(2017ZX10104001).
文摘Summary What is known about this topic?Few major outbreaks of coronavirus disease 2019(COVID-19)have occurred in China after major nonpharmaceutical interventions and vaccines have been deployed and implemented.However,sporadic outbreaks that had high possibility to be linked to cold chain products were reported in several cities of China..What is added by this report?In July 2020,a COVID-19 outbreak occurred in Dalian,China.The investigations of this outbreak strongly suggested that the infection source was from COVID-19 virus-contaminated packaging of frozen seafood during inbound unloading personnel contact.What are the implications for public health practice?Virus contaminated paper surfaces could maintain infectivity for at least 17–24 days at-25℃.Exposure to COVID-19 virus-contaminated surfaces is a potential route for introducing the virus to a susceptible population.Countries with no domestic transmission of COVID-19 should consider introducing prevention strategies for both inbound travellers and imported goods.Several measures to prevent the introduction of the virus via cold-chain goods can be implemented.
文摘目的:探讨补骨合剂协定方联合功能锻炼改善退行性腰椎管狭窄症患者腰椎功能的临床效果及对椎管内血液微循环、微炎状态的影响。方法:选取2017年2月至2018年5月中南大学湘雅医学院附属海口医院收治的退行性腰椎管狭窄症(气虚血瘀证)患者118例作为研究对象,随机分为对照组和观察组,每组59例。对照组患者给予氨糖美辛肠溶片联合功能锻炼治疗,观察组患者在对照组治疗的基础上给予补骨合剂协定方内服治疗,比较2组治疗的临床效果,观察患者治疗前后腰椎功能、腰椎疼痛程度及腰痛对日常生活能力的影响情况,测定患者的血液流变学指标,检测血清肿瘤坏死因子-α(TNF-α)、白细胞介素-1α(IL-1α)、单核细胞趋化蛋白-1(Monocyte Chemotactic Protein-1,MCP-1)、降钙素原(procalcitonin,PCT)水平。结果:对照组有效率为74.6%,明显低于观察组有效率91.5%,差异有统计学意义( P <0.05);治疗后,观察组的腰椎功能JOA评分较对照组升高明显,疼痛视觉模拟评分(VAS),Oswestry功能障碍指数(ODI)评分则较对照组更低,差异有统计学意义( P <0.05);观察组的血液流变学指标改善更明显,其全血黏度、血浆黏度、血细胞比容、纤维蛋白原均低于对照组,差异有统计学意义( P <0.05);观察组的机体微炎状态改善更明显,其TNF-α、IL-1α、MCP-1、PCT等炎性反应递质水平明显低于对照组,差异有统计学意义( P <0.05)。结论:加用补骨合剂协定方联合功能锻炼利于提高腰椎功能,减轻腰椎疼痛,提高日常生活能力。
文摘Research on two-dimensional(2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since the mechanical exfoliation of graphene in 2004. Starting from graphene, 2D materials now have become a big family with numerous members and diverse categories. The unique structural features and physicochemical properties of 2D materials make them one class of the most appealing candidates for a wide range of potential applications. In particular, we have seen some major breakthroughs made in the field of 2D materials in last five years not only in developing novel synthetic methods and exploring new structures/properties but also in identifying innovative applications and pushing forward commercialisation. In this review, we provide a critical summary on the recent progress made in the field of 2D materials with a particular focus on last five years. After a brief backgroundintroduction, we first discuss the major synthetic methods for 2D materials, including the mechanical exfoliation, liquid exfoliation, vapor phase deposition, and wet-chemical synthesis as well as phase engineering of 2D materials belonging to the field of phase engineering of nanomaterials(PEN). We then introduce the superconducting/optical/magnetic properties and chirality of 2D materials along with newly emerging magic angle 2D superlattices. Following that, the promising applications of 2D materials in electronics, optoelectronics, catalysis, energy storage, solar cells, biomedicine, sensors, environments, etc. are described sequentially. Thereafter, we present the theoretic calculations and simulations of 2D materials. Finally, after concluding the current progress, we provide some personal discussions on the existing challenges and future outlooks in this rapidly developing field.
基金support from diverse funding sources,including the National Key Program for S&T Research and Development of the Ministry of Science and Technology(MOST),Yifang Wang's Science Studio of the Ten Thousand Talents Project,the CAS Key Foreign Cooperation Grant,the National Natural Science Foundation of China(NSFC)Beijing Municipal Science&Technology Commission,the CAS Focused Science Grant,the IHEP Innovation Grant,the CAS Lead Special Training Programthe CAS Center for Excellence in Particle Physics,the CAS International Partnership Program,and the CAS/SAFEA International Partnership Program for Creative Research Teams.
文摘The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.
基金National Natural Science Funds for Distinguished Young Scholar under Grant No.51009086Hubei Key Laboratory of Roadway Bridge and Structure Engineering under Grant No.DQJJ201313Major State Basic Research Development Program of China(973 Program)under Grant No.2010CB732001
文摘Blast-induced dominant vibration frequency （DVF） involves a complex, nonlinear and small sample system considering rock properties, blasting parameters and topography. In this study, a combination of grey relational analysis and dimensional analysis procedures for prediction of dominant vibration frequency are presented. Six factors are selected from extensive effect factor sequences based on grey relational analysis, and then a novel blast-induced dominant vibration frequency prediction is obtained by dimensional analysis. In addition, the prediction is simplified by sensitivity analysis with 195 experimental blast records. Validation is carried out for the proposed formula based on the site test database of the first- period blasting excavation in the Guangdong Lufeng Nuclear Power Plant （GLNPP）. The results show the proposed approach has a higher fitting degree and smaller mean error when compared with traditional predictions.
基金supported by the grants from the National Natural Science Foundation of China(No.31571283)the CASSAFEA International Partnership Program for Creative Research Teams
文摘Research on CRISPR-Cas（clustered regularly interspaced short palindromic repeats-CRISPR associated protein） systems has led to the revolutionary CRISPR/Cas9 genome editing technique. However, for most archaea and half of bacteria, exploitation of their native CRISPR-Cas machineries may be more straightforward and convenient. In this study, we harnessed the native type I-B CRISPR-Cas system for precise genome editing in the polyploid haloarchaeon Haloarcula hispanica. After testing different designs, the editing tool was optimized to be a single plasmid that carries both the self-targeting miniCRISPR and a 600-800 bp donor. Significantly, chromosomal modifications, such as gene deletion, gene tagging or single nucleotide substitution, were precisely introduced into the vast majority of the transformants. Moreover, we showed that simultaneous editing of two genomic loci could also be readily achieved by one step. In summary, our data demonstrate that the haloarchaeal CRISPR-Cas system can be harnessed for genome editing in this polyploid archaeon, and highlight the convenience and efficiency of the native CRISPR-based genome editing strategy.
文摘Ralstonia solanacearum, the causative agent of bacterial wilt, is a soil-borne pathogen that poses a widespread threat to plants in the Solanaceae family. To elucidate the mechanism by which limonene exerts its effects on R. solanacearum, we first assessed the impact of limonene on the physiological indicators of the pathogen and subsequently analyzed its transcriptome and metabolome. Our findings indicate that limonene has a potent inhibitory effect on R. solanacearum, and it also suppresses the formation of the bacterial community biofilm. Limonene primarily regulates the terpene biosynthesis pathway in R. solanacearum, thereby potentially affecting signal transduction in the pathogen and disrupting its normal growth and development. These results significantly enhance our understanding of limonene’s response to the induction of bacterial wilt and provide a reference for further prevention and control of R. solanacearum.
基金supported by the Hunan Provincial Natural Science Foundation of China(2022JJ40176)the National Natural Science Foundation of China(32202692)the China Agriculture Research System of MOF and MARA,Earmarked Fund for China Agriculture Research System(CARS-35).
文摘Oligosaccharides are low molecular weight carbohydrates between monosaccharides and poly-saccharides,which consist of 2 to 20 monosaccharides linked by glycosidic bonds.They have the effects of promoting growth,regulating immunity,improving the structure of intestinal flora,and are anti-inflammatory and antioxidant.With the comprehensive implementation of the antibiotic prohibition policy in China,oligosaccharides as new green feed additive have been paid more attention.Oligosac-charides can be divided into the following 2 categories according to their digestive characteristics:one is easy to be absorbed by the intestine,called common oligosaccharides,such as sucrose and maltose oligosaccharide;the other is difficult to be absorbed by the intestine and has special physiological functions,called functional oligosaccharides.The common functional oligosaccharides include mannan oligosaccharides(MOS),fructo-oligosaccharides(FOS),chitosan oligosaccharides(COS),xylo-oligosaccharides(XOS)and so on.In this paper,we review the types and sources of functional oligo-saccharides,their application in pig nutrition,and the factors limiting their efficacy in recent years.This review provides the theoretical basis for further research of functional oligosaccharides,and the future application of alternative antibiotics in pig industry.
基金supported by the Key Program of National Natural Science Foundation of China(Grant No.51439008)National Natural Science Foundation of China(Grant Nos.41572307 and51779248)National Natural Science Funds for Distinguished Young Scholar of China(Grant No.41525009)
文摘In the process of blasting excavation, stress wave propagation and gas expansion can basically induce damage to surrounding rocks, which is detrimental to rock mass integrity and engineering safety. In this case, evaluation and control of blast-induced effects are essential to the safety of nearby buildings and integrity of bedrock in blasting field. In Fangchenggang nuclear power station of China, the drill-and- blast method was employed for bedrock excavation. In order to reduce the blast-induced damage zone, the wave propagation and associated damage to rock mass should be carefully investigated. In this paper, the wave propagation regressively obtained from field monitoring data was presented based on empirical formula （e.g. Sadovsloj formula）. The relationship between the peak particle velocity （PPV） at a distance of 30 m away from the charge hole and charge per delay in blast design was derived. Meanwhile, the acoustic tests before and after blasting were conducted to determine the damage depth of rock mass. The charge per delay in blast design was then calibrated based on the blast-induced wave propagation regularity. The results showed that a satisfactory effect was achieved on blast-induced damage control of rock mass. This could be helpful to rock damage control in similar blasting projects.
