Dear Editor,Lassa virus(LASV)is the causative agent of the acute viral hemorrhagic Lassa fever(LF),which is classified into Mammarenavirus within the Arenaviridae family,with a single-stranded,negative-sense,bisegment...Dear Editor,Lassa virus(LASV)is the causative agent of the acute viral hemorrhagic Lassa fever(LF),which is classified into Mammarenavirus within the Arenaviridae family,with a single-stranded,negative-sense,bisegmented RNA genome.Due to its high pathogenicity and lethality,LASV is considered as a priority threat to public health,with an estimated cases of 300,000 infections and 5000 deaths annually.LASV was first isolated and described as a clinical entity in 1969 in Lassa,Nigeria(Garry,2023).LASV isolates of different geographic and host origins are highly diverse in genomic sequences and phylogenetically classified into up to seven lineages,with each lineage predominately localized in specific countries.Although the research on LF has been carried out for decades since the pathogen first characterized,there is no approved antiviral drugs or vaccines for clinical use against LASV to date(Grant et al.,2023).One possible reason that hindered the development of countermeasures is that the preclinical studies on authentic LASV are restricted in high bio-containment biosafety level 4(BSL-4)facilities.In this letter,we describe isolation,and characterization of the LASV from the clinical samples.And we applied a coadministration assay of antiviral drugs for LASV by using a clinically isolated Mammarenavirus lassaense strain in the BSL-4 facility,aiming to investigate new therapeutic strategies for LASV infection.展开更多
Based on composite analysis and numerical simulations using a regional climate model(RegCM3), this paper analyzed the impact of the LHF anomaly in the tropical western Pacific on the precipitation over the south of Ch...Based on composite analysis and numerical simulations using a regional climate model(RegCM3), this paper analyzed the impact of the LHF anomaly in the tropical western Pacific on the precipitation over the south of China in June. The results are as follows.(1) Correlation analysis shows that the SC precipitation in June is negatively correlated with the LHF of the tropical western Pacific in May and June, especially in May. The SC precipitation in June appears to negatively correlate with low-level relative vorticity in the abnormal area of LHF in the tropical western Pacific.(2) The LHF anomaly in the tropical western Pacific is a vital factor affecting the flood and drought of SC in June. A conceptual model goes like this: When the LHF in the tropical western Pacific is abnormally increased(decreased), an anomalous cyclone(anticyclone) circulation is formed at the low-level troposphere to its northwest. As a result, an anomalous northeast(southwest) air flow affects the south of China, being disadvantageous(advantageous) to the transportation of water vapor to the region. Meanwhile, there is an anomalous anticyclone(cyclone) at the low-level troposphere and an anomalous cyclone(anticyclone) circulation at the high-level troposphere in the region, which is advantageous for downdraft(updraft) there. Therefore a virtual circulation forms updraft(downdraft) in the anomalous area of LHF and downdraft(updraft) in the south of China, which finally leads to the drought(flood) in the region.展开更多
In this investigation, comparative study of tensile and impact properties of multi-pass SMAW Armox500 T steel joints fabricated by austenitic stainless steel(ASS) and low hydrogen ferritic steel(LHF)consumables vis-a-...In this investigation, comparative study of tensile and impact properties of multi-pass SMAW Armox500 T steel joints fabricated by austenitic stainless steel(ASS) and low hydrogen ferritic steel(LHF)consumables vis-a-vis base metal was carried out. The tensile tests were conducted on computer controlled Walter t Bai Ag UTM at a nominal strain rate of 10à3 sà1. Subsequently, charpy impact tests were carried out on an instrumented Zwick-Roell test setup to obtain load vs. displacement and maximum energy absorbed vs. displacement of the specimen. It was observed that, the joint efficiency of weldment processed by LHF consumable was 41.7% and weldment processed by ASS was 30.6% of its base metal indicating the influence of electrode consumable on tensile properties of the joints. On the contrary, impact toughness of weldment processed by ASS was 20% more and weldment processed by LHF was 12% less than that of base metal. Microstructural studies also revealed that, ASS can be considered as a candidate welding consumable for good strain hardening and toughness of the welding joint in impact applications. However, LHF steel consumable is recommended for welding joints that requires higher joint efficiency under tensile loading conditions.展开更多
基金supported by the National Key Research and Development Program of China(2022YFC2303300,2023YFC2605504)the National Natural Science Foundation of China(82172273 and 31670165)the Open Research Fund Program of the State Key Laboratory of Virology of China(2023JZZD-01).
文摘Dear Editor,Lassa virus(LASV)is the causative agent of the acute viral hemorrhagic Lassa fever(LF),which is classified into Mammarenavirus within the Arenaviridae family,with a single-stranded,negative-sense,bisegmented RNA genome.Due to its high pathogenicity and lethality,LASV is considered as a priority threat to public health,with an estimated cases of 300,000 infections and 5000 deaths annually.LASV was first isolated and described as a clinical entity in 1969 in Lassa,Nigeria(Garry,2023).LASV isolates of different geographic and host origins are highly diverse in genomic sequences and phylogenetically classified into up to seven lineages,with each lineage predominately localized in specific countries.Although the research on LF has been carried out for decades since the pathogen first characterized,there is no approved antiviral drugs or vaccines for clinical use against LASV to date(Grant et al.,2023).One possible reason that hindered the development of countermeasures is that the preclinical studies on authentic LASV are restricted in high bio-containment biosafety level 4(BSL-4)facilities.In this letter,we describe isolation,and characterization of the LASV from the clinical samples.And we applied a coadministration assay of antiviral drugs for LASV by using a clinically isolated Mammarenavirus lassaense strain in the BSL-4 facility,aiming to investigate new therapeutic strategies for LASV infection.
基金National Natural Science Foundation of China under(41275060)National Key Basic Research Program of China(2014CB953903)+2 种基金Fundamental Research Funds for the Central Universities of China(13lgjc03)Key Project from National Natural Science Foundation of China(40730951)Open Project for Key Laboratory of Oceanological-Atmospheric Chemistry and Global Change from National Oceanological Administration(GCMAC0809)
文摘Based on composite analysis and numerical simulations using a regional climate model(RegCM3), this paper analyzed the impact of the LHF anomaly in the tropical western Pacific on the precipitation over the south of China in June. The results are as follows.(1) Correlation analysis shows that the SC precipitation in June is negatively correlated with the LHF of the tropical western Pacific in May and June, especially in May. The SC precipitation in June appears to negatively correlate with low-level relative vorticity in the abnormal area of LHF in the tropical western Pacific.(2) The LHF anomaly in the tropical western Pacific is a vital factor affecting the flood and drought of SC in June. A conceptual model goes like this: When the LHF in the tropical western Pacific is abnormally increased(decreased), an anomalous cyclone(anticyclone) circulation is formed at the low-level troposphere to its northwest. As a result, an anomalous northeast(southwest) air flow affects the south of China, being disadvantageous(advantageous) to the transportation of water vapor to the region. Meanwhile, there is an anomalous anticyclone(cyclone) at the low-level troposphere and an anomalous cyclone(anticyclone) circulation at the high-level troposphere in the region, which is advantageous for downdraft(updraft) there. Therefore a virtual circulation forms updraft(downdraft) in the anomalous area of LHF and downdraft(updraft) in the south of China, which finally leads to the drought(flood) in the region.
文摘In this investigation, comparative study of tensile and impact properties of multi-pass SMAW Armox500 T steel joints fabricated by austenitic stainless steel(ASS) and low hydrogen ferritic steel(LHF)consumables vis-a-vis base metal was carried out. The tensile tests were conducted on computer controlled Walter t Bai Ag UTM at a nominal strain rate of 10à3 sà1. Subsequently, charpy impact tests were carried out on an instrumented Zwick-Roell test setup to obtain load vs. displacement and maximum energy absorbed vs. displacement of the specimen. It was observed that, the joint efficiency of weldment processed by LHF consumable was 41.7% and weldment processed by ASS was 30.6% of its base metal indicating the influence of electrode consumable on tensile properties of the joints. On the contrary, impact toughness of weldment processed by ASS was 20% more and weldment processed by LHF was 12% less than that of base metal. Microstructural studies also revealed that, ASS can be considered as a candidate welding consumable for good strain hardening and toughness of the welding joint in impact applications. However, LHF steel consumable is recommended for welding joints that requires higher joint efficiency under tensile loading conditions.
