In this paper,a nonlinear time-fractional coupled diffusion system is solved by using a mixed finite element(MFE)method in space combined with L1-approximation and implicit second-order backward difference scheme in t...In this paper,a nonlinear time-fractional coupled diffusion system is solved by using a mixed finite element(MFE)method in space combined with L1-approximation and implicit second-order backward difference scheme in time.The stability for nonlinear fully discrete finite element scheme is analyzed and a priori error estimates are derived.Finally,some numerical tests are shown to verify our theoretical analysis.展开更多
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
基金the National Natural Science Fund(11661058,11301258,11361035)the Natural Science Fund of Inner Mongolia Autonomous Region(2016MS0102,2015MS0101)+1 种基金the Scientific Research Projection of Higher Schools of Inner Mongolia(NJZZ12011)the National Undergraduate Innovative Training Project(201510126026).
文摘In this paper,a nonlinear time-fractional coupled diffusion system is solved by using a mixed finite element(MFE)method in space combined with L1-approximation and implicit second-order backward difference scheme in time.The stability for nonlinear fully discrete finite element scheme is analyzed and a priori error estimates are derived.Finally,some numerical tests are shown to verify our theoretical analysis.
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.
