The novel severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)is the cause of a rapidly spreading illness,coronavirus disease 2019(COVID-19),affecting more than seventeen million people around the world.Diagnos...The novel severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)is the cause of a rapidly spreading illness,coronavirus disease 2019(COVID-19),affecting more than seventeen million people around the world.Diagnosis and treatment guidelines for clinicians caring for patients are needed.In the early stage,we have issued"A rapid advice guideline for the diagnosis and treatment of 2019 novel coronavirus(2019-nCoV)infected pneumonia(standard version)";now there are many direct evidences emerged and may change some of previous recommendations and it is ripe for develop an evidence-based guideline.We formed a working group of clinical experts and methodologists.The steering group members proposed 29 questions that are relevant to the management of COVID-19 covering the following areas:chemoprophylaxis,diagnosis,treatments,and discharge management.We searched the literature for direct evidence on the management of COVID-19,and assessed its certainty generated recommendations using the Grading of Recommendations,Assessment,Development and Evaluation(GRADE)approach.Recommendations were either strong or weak,or in the form of ungraded consensus-based statement.Finally,we issued 34 statements.Among them,6 were strong recommendations for,14 were weak recommendations for,3 were weak recommendations against and 11 were ungraded consensus-based statement.They covered topics of chemoprophylaxis(including agents and Traditional Chinese Medicine(TCM)agents),diagnosis(including clinical manifestations,reverse transcription-polymerase chain reaction(RT-PCR),respiratory tract specimens,IgM and IgG antibody tests,chest computed tomography,chest X-ray,and CT features of asymptomatic infections),treatments(including lopinavirritonavir,umifenovir,favipiravir,interferon,remdesivir,combination of antiviral drugs,hydroxychloroquine/chloroquine,interleukin-6 inhibitors,interleukin-1 inhibitors,glucocorticoid,qingfei paidu decoction,lianhua qingwen granules/capsules,convalescent plasma,lung transplantation,invasive or noninvasive ventilat展开更多
SARS-CoV-2 causes the pandemic of COVID-19 and no effective drugs for this disease are available thus far.Due to the high infectivity and pathogenicity of this virus,all studies on the live virus are strictly confined...SARS-CoV-2 causes the pandemic of COVID-19 and no effective drugs for this disease are available thus far.Due to the high infectivity and pathogenicity of this virus,all studies on the live virus are strictly confined in the biosafety level 3(BSL3)laboratory but this would hinder the basic research and antiviral drug development of SARS-CoV-2 because the BSL3 facility is not commonly available and the work in the containment is costly and laborious.In this study,we constructed a reverse genetics system of SARS-CoV-2 by assembling the viral cDNA in a bacterial artificial chromosome(BAC)vector with deletion of the spike(S)gene.Transfection of the cDNA into cells results in the production of an RNA replicon that keeps the capability of genome or subgenome replication but is deficient in virion assembly and infection due to the absence of S protein.Therefore,such a replicon system is not infectious and can be used in ordinary biological laboratories.We confirmed the efficient replication of the replicon by demonstrating the expression of the subgenomic RNAs which have similar profiles to the wild-type virus.By mutational analysis of nsp12 and nsp14,we showed that the RNA polymerase,exonuclease,and cap N7 methyltransferase play essential roles in genome replication and sgRNA production.We also created a SARS-CoV-2 replicon carrying a luciferase reporter gene and this system was validated by the inhibition assays with known anti-SARS-CoV-2 inhibitors.Thus,such a one-plasmid system is biosafe and convenient to use,which will benefit both fundamental research and development of antiviral drugs.展开更多
目的目前关于医疗机构工作人员是否需要戴口罩仍存在较大争议,本研究意在评价和总结针对这一问题的现有最佳证据,以期为临床医务工作人员使用口罩提供参考。方法计算机检索PubMed、Cochrane图书馆、Web of Science、CINAHL、中国知网、...目的目前关于医疗机构工作人员是否需要戴口罩仍存在较大争议,本研究意在评价和总结针对这一问题的现有最佳证据,以期为临床医务工作人员使用口罩提供参考。方法计算机检索PubMed、Cochrane图书馆、Web of Science、CINAHL、中国知网、万方、维普、中国生物医学文献数据库,指南数据库平台及相关专业学会组织,检索时限为建库至2019年10月27日,以获取相关指南、专家共识、系统评价,应用国际公认的质量评价工具对纳入的证据进行质量评价,汇总现有证据对医疗机构人员是否需要戴口罩这一问题的相关推荐内容。结果共纳入35篇文献,其中6篇指南,27篇专家共识,2篇系统评价,证据质量整体较高。现有证据均推荐使用口罩作为个人防护措施之一,且与不使用呼吸防护设备相比,戴口罩在预防院内感染方面具有明显的优势,并根据不同的应用情景如手术区域、实验室区、产科等提出多项推荐意见。结论现有证据充分认可戴口罩作为个人防护措施之一在医疗机构中预防院内感染的重要作用。但本研究纳入的证据质量仍有一定的局限性。临床医务工作人员应当结合自身工作经验、临床实际情况等因素综合考虑,合理、规范使用口罩。展开更多
Sri Lankan cassava mosaic virus(SLCMV)is a prominent causative agent of cassava mosaic disease in Asia and relies on the whitefly Bemisia tabaci cryptic complex for its transmission.However,the molecular mechanisms in...Sri Lankan cassava mosaic virus(SLCMV)is a prominent causative agent of cassava mosaic disease in Asia and relies on the whitefly Bemisia tabaci cryptic complex for its transmission.However,the molecular mechanisms involved in SLCMV transmission by B.tabaci have yet to be understood.In this study,we identified an aminopeptidase N-like protein(BtAPN)in B.tabaci Asia II 1,an efficient vector of SLCMV,which is involved in the SLCMV transmission process.Through the use of glutathione S-transferase pull-down assay and LC-MS/MS analysis,we demonstrated the interaction between BtAPN and the coat protein(CP)of SLCMV.This interaction was further confirmed in vitro,and we observed an induction of BtAPN gene expression following SLCMV infection.By interfering with the function of BtAPN,the quantities of SLCMV were significantly reduced in various parts of B.tabaci Asia II 1,including the whole body,midgut,hemolymph,and primary salivary gland.Furthermore,we discovered that BtAPN is conserved in B.tabaci Middle East-Asia Minor 1(MEAM1)and interacts with the CP of tomato yellow leaf curl virus(TYLCV),a begomovirus known to cause severe damage to tomato production.Blocking BtAPN with antibody led to a significant reduction in the quantities of TYLCV in whitefly whole body and organs/tissues.These results demonstrate that BtAPN plays a generic role in interacting with the CP of begomoviruses and positively regulates their acquisition by the whitefly.展开更多
The DarkSHINE experiment proposes a novel approach to single-electron-on-fixed-target exploration that focuses on the search for dark photons through their invisible decay into dark matter particles.Central to this in...The DarkSHINE experiment proposes a novel approach to single-electron-on-fixed-target exploration that focuses on the search for dark photons through their invisible decay into dark matter particles.Central to this initiative is an advanced tracking detector designed to achieve exceptional sensitivity in the detection of light dark matter candidates.This study evaluates the performance of several prototype AC-coupled low-gain avalanche diode(AC-LGAD)strip sensors specifically developed for the DarkSHINE tracking detector.The electrical properties of the sensors from two batches of wafers with different n^(+)doses are thoroughly evaluated.Spatial and temporal resolutions are measured using an infrared laser source.The spatial resolutions range from 6.5 to 8.2μm and from 8.8 to 12.3μm for the sensors from two distinct dose batches,each with a 100μm pitch size.Furthermore,the sensors demonstrate time resolutions of 8.3 and 11.4 ps,underscoring the potential of AC-LGAD technology in enhancing the performance of the DarkSHINE tracking detector.展开更多
Piezoelectric ceramic based high-temperature acoustic emission(AE)sensor is required urgently in the structural health monitoring of high-temperature fields.In this research,a series of 0.45(BiSc_(x)O_(3)-BiFe_(1-x)O_...Piezoelectric ceramic based high-temperature acoustic emission(AE)sensor is required urgently in the structural health monitoring of high-temperature fields.In this research,a series of 0.45(BiSc_(x)O_(3)-BiFe_(1-x)O_(3))-0.48PbTiO_(3)-0.07BaTiO_(3)(BSc_(x)Fe_(1-x)-PT-BT,n(Sc)/n(Fe)=0.4/0.6-0.6/0.4)ceramics with both high Curie temperature and large piezoelectric constant were presented.The structure and electrical properties of BSc_(x)Fe_(1-x)-PT-BT ceramics as a function of n(Sc)/n(Fe)have been systematically investigated.All the ceramics possess a perovskite structure,and the phase approaches from the rhombohedral toward the tetragonal phase with the decrease of n(Sc)/n(Fe).The BSc_(0.5)Fe_(0.5)-PT-BT and BSc_(0.5)Fe_(0.5)-PT-BT piezoelectric ceramics exhibit good piezoelectricity(d_(33)=250-281 pC/N),high Curie temperature(T_(C)=430-450℃)and excellent temperature stability.These improvements are greatly attributed to the balance between rhombohedral and tetragonal phase near morphotropic phase boundary with dense microstructure of ceramics.AE sensor based BSc_(0.5)Fe_(0.5)-PT-BT piezoelectric ceramic was designed,prepared and tested.The high-temperature stability of AE sensor was characterized through pencil-lead breaking with in situ high-temperature test.The noise of AE sensor is less than 40 dB,and the acoustic signal is up to 90 dB at 200℃.As a result,AE sensors based on BSc_(x)Fe_(1-x)-PT-BT piezoelectric ceramics are expected to be applied into the structural health monitoring of high temperature fields.展开更多
Dynamic beam steering with unlimited angular range and fast speed remains a challenge in the terahertz gap,which is urgently needed for next-generation target tracking,wireless communications,and imaging applications....Dynamic beam steering with unlimited angular range and fast speed remains a challenge in the terahertz gap,which is urgently needed for next-generation target tracking,wireless communications,and imaging applications.Different from metasurface phased arrays with element-level phase control,here we steer the beam by globally engineering the diffraction of two cascaded metagratings during in-plane rotation.Benefiting from large-angle diffraction and flexible on/off control of the diffraction channels,a pair of metagratings with optimized supercells and proper orientation successfully directs the incoming beam towards any arbitrary direction over the transmission half space,with the steering speed improved more than twice that of the small-angle diffractive designs.Single-beam and dual-beam steering within the solid angle of 1.56πand elevation angle of±77°has been demonstrated with average throughput efficiency of 41.4%at 0.14 THz,which can be generalized to multiple-beam cases.The dual diffraction engineering scheme offers a clear physical picture for beamforming and greatly simplifies the device structure,with additional merits of large aperture and low power consumption.展开更多
基金supported(in part)by the National Key Research and Development Program of China(2020YFC0845500)the Special Project for Emergency of Hubei Province(2020FCA008)the First Level Funding of the Second Medical Leading Talent Project in Hubei Province。
文摘The novel severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)is the cause of a rapidly spreading illness,coronavirus disease 2019(COVID-19),affecting more than seventeen million people around the world.Diagnosis and treatment guidelines for clinicians caring for patients are needed.In the early stage,we have issued"A rapid advice guideline for the diagnosis and treatment of 2019 novel coronavirus(2019-nCoV)infected pneumonia(standard version)";now there are many direct evidences emerged and may change some of previous recommendations and it is ripe for develop an evidence-based guideline.We formed a working group of clinical experts and methodologists.The steering group members proposed 29 questions that are relevant to the management of COVID-19 covering the following areas:chemoprophylaxis,diagnosis,treatments,and discharge management.We searched the literature for direct evidence on the management of COVID-19,and assessed its certainty generated recommendations using the Grading of Recommendations,Assessment,Development and Evaluation(GRADE)approach.Recommendations were either strong or weak,or in the form of ungraded consensus-based statement.Finally,we issued 34 statements.Among them,6 were strong recommendations for,14 were weak recommendations for,3 were weak recommendations against and 11 were ungraded consensus-based statement.They covered topics of chemoprophylaxis(including agents and Traditional Chinese Medicine(TCM)agents),diagnosis(including clinical manifestations,reverse transcription-polymerase chain reaction(RT-PCR),respiratory tract specimens,IgM and IgG antibody tests,chest computed tomography,chest X-ray,and CT features of asymptomatic infections),treatments(including lopinavirritonavir,umifenovir,favipiravir,interferon,remdesivir,combination of antiviral drugs,hydroxychloroquine/chloroquine,interleukin-6 inhibitors,interleukin-1 inhibitors,glucocorticoid,qingfei paidu decoction,lianhua qingwen granules/capsules,convalescent plasma,lung transplantation,invasive or noninvasive ventilat
基金supported by Grants(the National Natural Science Foundation of China#32041002,#31971161,#31900546 and#81620108020)the Guangdong Science and Technology Department(#2019A1515011332)+1 种基金the Shenzhen Science and Technology Innovation Program(JSGG20200225150431472,JCYJ20190807160615255,JCYJ20190807153203560,and KQTD20180411143323605)supported by the Guangdong Zhujiang Leading Talents Programme and the National Tenthousand Talents Program。
文摘SARS-CoV-2 causes the pandemic of COVID-19 and no effective drugs for this disease are available thus far.Due to the high infectivity and pathogenicity of this virus,all studies on the live virus are strictly confined in the biosafety level 3(BSL3)laboratory but this would hinder the basic research and antiviral drug development of SARS-CoV-2 because the BSL3 facility is not commonly available and the work in the containment is costly and laborious.In this study,we constructed a reverse genetics system of SARS-CoV-2 by assembling the viral cDNA in a bacterial artificial chromosome(BAC)vector with deletion of the spike(S)gene.Transfection of the cDNA into cells results in the production of an RNA replicon that keeps the capability of genome or subgenome replication but is deficient in virion assembly and infection due to the absence of S protein.Therefore,such a replicon system is not infectious and can be used in ordinary biological laboratories.We confirmed the efficient replication of the replicon by demonstrating the expression of the subgenomic RNAs which have similar profiles to the wild-type virus.By mutational analysis of nsp12 and nsp14,we showed that the RNA polymerase,exonuclease,and cap N7 methyltransferase play essential roles in genome replication and sgRNA production.We also created a SARS-CoV-2 replicon carrying a luciferase reporter gene and this system was validated by the inhibition assays with known anti-SARS-CoV-2 inhibitors.Thus,such a one-plasmid system is biosafe and convenient to use,which will benefit both fundamental research and development of antiviral drugs.
文摘目的目前关于医疗机构工作人员是否需要戴口罩仍存在较大争议,本研究意在评价和总结针对这一问题的现有最佳证据,以期为临床医务工作人员使用口罩提供参考。方法计算机检索PubMed、Cochrane图书馆、Web of Science、CINAHL、中国知网、万方、维普、中国生物医学文献数据库,指南数据库平台及相关专业学会组织,检索时限为建库至2019年10月27日,以获取相关指南、专家共识、系统评价,应用国际公认的质量评价工具对纳入的证据进行质量评价,汇总现有证据对医疗机构人员是否需要戴口罩这一问题的相关推荐内容。结果共纳入35篇文献,其中6篇指南,27篇专家共识,2篇系统评价,证据质量整体较高。现有证据均推荐使用口罩作为个人防护措施之一,且与不使用呼吸防护设备相比,戴口罩在预防院内感染方面具有明显的优势,并根据不同的应用情景如手术区域、实验室区、产科等提出多项推荐意见。结论现有证据充分认可戴口罩作为个人防护措施之一在医疗机构中预防院内感染的重要作用。但本研究纳入的证据质量仍有一定的局限性。临床医务工作人员应当结合自身工作经验、临床实际情况等因素综合考虑,合理、规范使用口罩。
基金Financial support for this article was provided by the National Natural Science Foundation of China(32161143008,31925233)the Bill&Melinda Gates Foundation(Investment ID OPP1149777)Wilmer J.Cuellar,is supported by the Australian Centre for International Agricultural Research(ACIAR),and the One CGIAR initiative on Plant Health(PHI).
文摘Sri Lankan cassava mosaic virus(SLCMV)is a prominent causative agent of cassava mosaic disease in Asia and relies on the whitefly Bemisia tabaci cryptic complex for its transmission.However,the molecular mechanisms involved in SLCMV transmission by B.tabaci have yet to be understood.In this study,we identified an aminopeptidase N-like protein(BtAPN)in B.tabaci Asia II 1,an efficient vector of SLCMV,which is involved in the SLCMV transmission process.Through the use of glutathione S-transferase pull-down assay and LC-MS/MS analysis,we demonstrated the interaction between BtAPN and the coat protein(CP)of SLCMV.This interaction was further confirmed in vitro,and we observed an induction of BtAPN gene expression following SLCMV infection.By interfering with the function of BtAPN,the quantities of SLCMV were significantly reduced in various parts of B.tabaci Asia II 1,including the whole body,midgut,hemolymph,and primary salivary gland.Furthermore,we discovered that BtAPN is conserved in B.tabaci Middle East-Asia Minor 1(MEAM1)and interacts with the CP of tomato yellow leaf curl virus(TYLCV),a begomovirus known to cause severe damage to tomato production.Blocking BtAPN with antibody led to a significant reduction in the quantities of TYLCV in whitefly whole body and organs/tissues.These results demonstrate that BtAPN plays a generic role in interacting with the CP of begomoviruses and positively regulates their acquisition by the whitefly.
基金supported by the National Natural Science Foundation of China(No.12150006)Shanghai Pilot Program for Basic Research-Shanghai Jiao Tong University(No.21TQ1400209)the Young Talents of National Talent Support Programs(No.24Z130300579).
文摘The DarkSHINE experiment proposes a novel approach to single-electron-on-fixed-target exploration that focuses on the search for dark photons through their invisible decay into dark matter particles.Central to this initiative is an advanced tracking detector designed to achieve exceptional sensitivity in the detection of light dark matter candidates.This study evaluates the performance of several prototype AC-coupled low-gain avalanche diode(AC-LGAD)strip sensors specifically developed for the DarkSHINE tracking detector.The electrical properties of the sensors from two batches of wafers with different n^(+)doses are thoroughly evaluated.Spatial and temporal resolutions are measured using an infrared laser source.The spatial resolutions range from 6.5 to 8.2μm and from 8.8 to 12.3μm for the sensors from two distinct dose batches,each with a 100μm pitch size.Furthermore,the sensors demonstrate time resolutions of 8.3 and 11.4 ps,underscoring the potential of AC-LGAD technology in enhancing the performance of the DarkSHINE tracking detector.
基金Project(SDBX2020010) supported by Shandong Postdoctoral Innovative Talents Support Plan,ChinaProjects(U1806221,U2006218) supported by the National Natural Science Foundation of China+1 种基金Project(ZR2020KA003)supported by Shandong Provincial Natural Science Foundation,ChinaProjects(2019GXRC017,2020GXRC051)supported by the Project of “20 Items of University” of Jinan,China。
文摘Piezoelectric ceramic based high-temperature acoustic emission(AE)sensor is required urgently in the structural health monitoring of high-temperature fields.In this research,a series of 0.45(BiSc_(x)O_(3)-BiFe_(1-x)O_(3))-0.48PbTiO_(3)-0.07BaTiO_(3)(BSc_(x)Fe_(1-x)-PT-BT,n(Sc)/n(Fe)=0.4/0.6-0.6/0.4)ceramics with both high Curie temperature and large piezoelectric constant were presented.The structure and electrical properties of BSc_(x)Fe_(1-x)-PT-BT ceramics as a function of n(Sc)/n(Fe)have been systematically investigated.All the ceramics possess a perovskite structure,and the phase approaches from the rhombohedral toward the tetragonal phase with the decrease of n(Sc)/n(Fe).The BSc_(0.5)Fe_(0.5)-PT-BT and BSc_(0.5)Fe_(0.5)-PT-BT piezoelectric ceramics exhibit good piezoelectricity(d_(33)=250-281 pC/N),high Curie temperature(T_(C)=430-450℃)and excellent temperature stability.These improvements are greatly attributed to the balance between rhombohedral and tetragonal phase near morphotropic phase boundary with dense microstructure of ceramics.AE sensor based BSc_(0.5)Fe_(0.5)-PT-BT piezoelectric ceramic was designed,prepared and tested.The high-temperature stability of AE sensor was characterized through pencil-lead breaking with in situ high-temperature test.The noise of AE sensor is less than 40 dB,and the acoustic signal is up to 90 dB at 200℃.As a result,AE sensors based on BSc_(x)Fe_(1-x)-PT-BT piezoelectric ceramics are expected to be applied into the structural health monitoring of high temperature fields.
基金National Key Research and Development Program of China(2017YFA0701000)National Natural Science Foundation of China(61831012,62005140,62175118)。
文摘Dynamic beam steering with unlimited angular range and fast speed remains a challenge in the terahertz gap,which is urgently needed for next-generation target tracking,wireless communications,and imaging applications.Different from metasurface phased arrays with element-level phase control,here we steer the beam by globally engineering the diffraction of two cascaded metagratings during in-plane rotation.Benefiting from large-angle diffraction and flexible on/off control of the diffraction channels,a pair of metagratings with optimized supercells and proper orientation successfully directs the incoming beam towards any arbitrary direction over the transmission half space,with the steering speed improved more than twice that of the small-angle diffractive designs.Single-beam and dual-beam steering within the solid angle of 1.56πand elevation angle of±77°has been demonstrated with average throughput efficiency of 41.4%at 0.14 THz,which can be generalized to multiple-beam cases.The dual diffraction engineering scheme offers a clear physical picture for beamforming and greatly simplifies the device structure,with additional merits of large aperture and low power consumption.
