The influenza A(H1 N1)pdm09 virus emerged in 2009 and has been continuously circulating in humans for over ten years.Here,we analyzed a clinical influenza A(H1 N1)pdm09-infected patient case hospitalized for two month...The influenza A(H1 N1)pdm09 virus emerged in 2009 and has been continuously circulating in humans for over ten years.Here,we analyzed a clinical influenza A(H1 N1)pdm09-infected patient case hospitalized for two months in Guangdong(from December 14,2019 to February 15,2020).This isolate,named A/Guangdong/LCF/2019(LCF/19),was genetically sequenced,rescued by reverse genetics,and phylogenetically analyzed in the context of other relevant pdm09 isolates.Compared with earlier isolates,this pdm09 virus’s genetic sequence contains four substitutions,S186 P,T188 I,D190 A,and Q192 E,of the hemagglutinin(HA)segment at position 186–192(H3 numbering)in the epitope Sb,and two of which are located at the 190-helix.Phylogenetic analysis indicated that the epitope Sb started undergoing a rapid antigenic change in2018.To characterize the pathogenicity of this novel substitution motif,a panel of reassortant viruses containing the LCF/2019 HA segment or the chimeric HA segment with the four substitutions were rescued.Kinetic growth data revealed that the reassortant viruses,including the LCF/2019 with the PTIAAQE substitution,propagated faster than those rescued ones having the STTADQQ motif in the epitope Sb in Madin-Darby Canine Kidney(MDCK)cells.The HI test showed that the binding activity of escape mutant to 2018 pdm09 sera was weaker than GLW/2018,suggesting that old vaccines might not effectively protect people from infection.Due to the difference in the selection of vaccine strains,people vaccinated in the southern hemisphere could still suffer a severe infection if infected with this antigenic drift pdm09 virus.展开更多
Scavenged energy from ambient vibrations has become a promising energy supply for autonomous microsystems.However,restricted by device size,most MEMS vibration energy harvesters have much higher resonant frequencies t...Scavenged energy from ambient vibrations has become a promising energy supply for autonomous microsystems.However,restricted by device size,most MEMS vibration energy harvesters have much higher resonant frequencies than environmental vibrations,which reduces scavenged power and limits practical applicability.Herein,we propose a MEMS multimodal vibration energy harvester with specifically cascaded flexible PDMS and"zigzag"silicon beams to simultaneously lower the resonant frequency to the ultralow-frequency level and broaden the bandwidth.A two-stage architecture is designed,in which the primary subsystem consists of suspended PDMS beams characterized by a low Young's modulus,and the secondary system consists of zigzag silicon beams.We also propose a PDMS lift-off process to fabricate the suspended flexible beams and the compatible microfabrication method shows high yield and good repeatability.The fabricated MEMS energy harvester can operate at ultralow resonant frequencies of 3 and 23 Hz,with an NPD index of 1.73μW/cm^(3)/g^(2)@3 Hz.The factors underlying output power degradation in the low-frequency range and potential enhancement strategies are discussed.This work offers new insights into achieving MEMS-scale energy harvesting with ultralow frequency response.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.82074311)the General Project of Guangzhou Medical University(Grant No.SKLRD-MS201908)the Yunnan Provincial Science and Technology Department(Grant No.202005AF150043)。
文摘The influenza A(H1 N1)pdm09 virus emerged in 2009 and has been continuously circulating in humans for over ten years.Here,we analyzed a clinical influenza A(H1 N1)pdm09-infected patient case hospitalized for two months in Guangdong(from December 14,2019 to February 15,2020).This isolate,named A/Guangdong/LCF/2019(LCF/19),was genetically sequenced,rescued by reverse genetics,and phylogenetically analyzed in the context of other relevant pdm09 isolates.Compared with earlier isolates,this pdm09 virus’s genetic sequence contains four substitutions,S186 P,T188 I,D190 A,and Q192 E,of the hemagglutinin(HA)segment at position 186–192(H3 numbering)in the epitope Sb,and two of which are located at the 190-helix.Phylogenetic analysis indicated that the epitope Sb started undergoing a rapid antigenic change in2018.To characterize the pathogenicity of this novel substitution motif,a panel of reassortant viruses containing the LCF/2019 HA segment or the chimeric HA segment with the four substitutions were rescued.Kinetic growth data revealed that the reassortant viruses,including the LCF/2019 with the PTIAAQE substitution,propagated faster than those rescued ones having the STTADQQ motif in the epitope Sb in Madin-Darby Canine Kidney(MDCK)cells.The HI test showed that the binding activity of escape mutant to 2018 pdm09 sera was weaker than GLW/2018,suggesting that old vaccines might not effectively protect people from infection.Due to the difference in the selection of vaccine strains,people vaccinated in the southern hemisphere could still suffer a severe infection if infected with this antigenic drift pdm09 virus.
基金supported by the National Natural Science Foundation of China under Grant 61834003,Grant 62174097,and Grant 62201528.
文摘Scavenged energy from ambient vibrations has become a promising energy supply for autonomous microsystems.However,restricted by device size,most MEMS vibration energy harvesters have much higher resonant frequencies than environmental vibrations,which reduces scavenged power and limits practical applicability.Herein,we propose a MEMS multimodal vibration energy harvester with specifically cascaded flexible PDMS and"zigzag"silicon beams to simultaneously lower the resonant frequency to the ultralow-frequency level and broaden the bandwidth.A two-stage architecture is designed,in which the primary subsystem consists of suspended PDMS beams characterized by a low Young's modulus,and the secondary system consists of zigzag silicon beams.We also propose a PDMS lift-off process to fabricate the suspended flexible beams and the compatible microfabrication method shows high yield and good repeatability.The fabricated MEMS energy harvester can operate at ultralow resonant frequencies of 3 and 23 Hz,with an NPD index of 1.73μW/cm^(3)/g^(2)@3 Hz.The factors underlying output power degradation in the low-frequency range and potential enhancement strategies are discussed.This work offers new insights into achieving MEMS-scale energy harvesting with ultralow frequency response.
