NADC34-like porcine reproductive and respiratory syndrome virus(PRRSV),which first appeared in China in 2017,is currently one of the main epidemic strains in China.In this study,we found that a new variant of NADC34-l...NADC34-like porcine reproductive and respiratory syndrome virus(PRRSV),which first appeared in China in 2017,is currently one of the main epidemic strains in China.In this study,we found that a new variant of NADC34-like PRRSV evolved,named the L1A variant.The phylogenetics,epidemic status,and pathogenicity of the LA variants were subsequently comprehensively evaluated.Based on the results of the ORF5 phylogenetic analysis,the L1A variants were classified as NADC34-like PPRSV.All the strains had the same discontinuous 131-aa deletion in the NSP2 region(similar to that in the NADC30).Recombination analysis revealed that the L1A variants were recombinant viruses that contained an NADC30-like PRRSV skeleton,a nonstructural protein-encoding gene region obtained in part from JXA1-like PRRSV and a ORF2-ORF6 gene region partly obtained from NADC34-like PRRSV and that exhibited similar recombination patterns.We successfully isolated the L1A variant TZJ2756 from PAMs and Marc-145 cells.In animal experiments,TZJ2756 exhibited moderate pathogenicity in piglets,causing obvious clinical symptoms,namely,persistent fever,significantly reduced body weight,interstitial edema and severe interstitial pneumonia in the lungs,and prolonged high-load viremia.L1A variants have been detected in at least 12 provinces in China and share many similar epidemiological characteristics with the American L1C variant.This research will enhance our understanding of the prevalence of L1A variants and furnish valuable data for the ongoing monitoring of NADC34-like PRRSV in China.展开更多
This paper considers that the crystal grains of HDDR Pr2Fe14B permanent magnetic material are cubic, the size is 0.3 μm, and the crystal grains are in simple cubic accumulation. It is considered that there are bounda...This paper considers that the crystal grains of HDDR Pr2Fe14B permanent magnetic material are cubic, the size is 0.3 μm, and the crystal grains are in simple cubic accumulation. It is considered that there are boundary phases between grains. It is assumed that the boundary phases are non-magnetic phases with the thickness of d, and evenly distributed between grains. The anisotropy expression of single grain boundary is given considering structure defect and intergranular exchange coupling interaction. Based on micro-magnetic simulation calculation, the variation of the average anisotropy of a single grain with the structural defects and boundary phases was calculated. The results show that when the thickness of structural defects is constant, the average anisotropy of a single grain decreases with increasing of grain boundary phase thickness, and while the thickness of grain boundary phase is constant, it also decreases with increasing of structural defect thickness.展开更多
基金supported by grants from the National Natural Science Foundation of China(32172890 and 32002315)the National Key Research and Development Program of China(2022YFF0711004)+3 种基金the Natural Science Foundation of Heilongjiang Province,China(YQ2022C042)the State Key Laboratory of Veterinary Biotechnology Foundation of China(SKLVBF202208)the Postdoctoral Fellowship Program of CPSF,China(GZC20233062)the National Center of Technology Innovation for Pigs,China(NCTIP-XD/C09)。
文摘NADC34-like porcine reproductive and respiratory syndrome virus(PRRSV),which first appeared in China in 2017,is currently one of the main epidemic strains in China.In this study,we found that a new variant of NADC34-like PRRSV evolved,named the L1A variant.The phylogenetics,epidemic status,and pathogenicity of the LA variants were subsequently comprehensively evaluated.Based on the results of the ORF5 phylogenetic analysis,the L1A variants were classified as NADC34-like PPRSV.All the strains had the same discontinuous 131-aa deletion in the NSP2 region(similar to that in the NADC30).Recombination analysis revealed that the L1A variants were recombinant viruses that contained an NADC30-like PRRSV skeleton,a nonstructural protein-encoding gene region obtained in part from JXA1-like PRRSV and a ORF2-ORF6 gene region partly obtained from NADC34-like PRRSV and that exhibited similar recombination patterns.We successfully isolated the L1A variant TZJ2756 from PAMs and Marc-145 cells.In animal experiments,TZJ2756 exhibited moderate pathogenicity in piglets,causing obvious clinical symptoms,namely,persistent fever,significantly reduced body weight,interstitial edema and severe interstitial pneumonia in the lungs,and prolonged high-load viremia.L1A variants have been detected in at least 12 provinces in China and share many similar epidemiological characteristics with the American L1C variant.This research will enhance our understanding of the prevalence of L1A variants and furnish valuable data for the ongoing monitoring of NADC34-like PRRSV in China.
文摘This paper considers that the crystal grains of HDDR Pr2Fe14B permanent magnetic material are cubic, the size is 0.3 μm, and the crystal grains are in simple cubic accumulation. It is considered that there are boundary phases between grains. It is assumed that the boundary phases are non-magnetic phases with the thickness of d, and evenly distributed between grains. The anisotropy expression of single grain boundary is given considering structure defect and intergranular exchange coupling interaction. Based on micro-magnetic simulation calculation, the variation of the average anisotropy of a single grain with the structural defects and boundary phases was calculated. The results show that when the thickness of structural defects is constant, the average anisotropy of a single grain decreases with increasing of grain boundary phase thickness, and while the thickness of grain boundary phase is constant, it also decreases with increasing of structural defect thickness.
