Four species of porcine circoviruses(PCV1–4)have been reported to circulate in Chinese domestic pigs,while the epizootiology of these viruses in free-ranging wild boars in China remains unknown.In this study,tissue a...Four species of porcine circoviruses(PCV1–4)have been reported to circulate in Chinese domestic pigs,while the epizootiology of these viruses in free-ranging wild boars in China remains unknown.In this study,tissue and serum samples collected from diseased or apparently healthy wild boars between 2018 and 2020 in 19 regions of China were tested for the prevalence of PCV1–4 infections.Positive rates of PCV1,PCV2,and PCV3 DNA in the tissue samples of Chinese wild boars were 1.6%(4/247),58.3%(144/247),and 10.9%(27/247)respectively,with none positive for PCV4.Sequence analysis of viral genome showed that the four PCV1 strains distributed in Hunan and Inner Mongolia shared 97.5%–99.6%sequence identity with global distributed reference strains.Comparison of the ORF2 gene sequences showed that 80 PCV2 strains widely distributed in 18 regions shared 79.5%–100%sequence identity with reference strains from domestic pigs and wild boars,and were grouped into PCV2a(7),PCV2b(31)and PCV2d(42).For PCV3,17 sequenced strains shared 97.2%–100%nucleotide identity at the genomic level and could be divided into PCV3a(3),PCV3b(2)and PCV3c(12)based on the phylogeny of ORF2 gene sequences.Serological data revealed antibody positive rates against PCV1 and PCV2 of 11.4%(19/167)and 53.9%(90/167)respectively.The data obtained in this study improved our understanding about the epidemiological situations of PCVs infection in free-ranging wild boars in China and will be valuable for the prevention and control of diseases caused by PCVs infection.展开更多
GdNi5 nanoparticles and GdNis/Gd2O3 nanocapsules (with GdNi5 core and Gd2O3 shell) were prepared by arcdischarge technique under different hydrogen partial pressure. The GdNi5 nanoparticles show irregular spherical ...GdNi5 nanoparticles and GdNis/Gd2O3 nanocapsules (with GdNi5 core and Gd2O3 shell) were prepared by arcdischarge technique under different hydrogen partial pressure. The GdNi5 nanoparticles show irregular spherical shape and have a size distribution of 10-50 nm with an average diameter of 15 nm. In comparison, the GdNi5/Gd2O3 nanocapsules present spherical morphology and show a size distribution of 10-100 nm with an average diameter of 60 nm. Under a magnetic field change of 50 kOe, the maximum magnetic entropy change of GdNi5 nanoparticles is 13.5 J/(kg K) at 5 K, while the corresponding value of the GdNis/Gd2O3 nanocapsuels is only 5.7 J/(kg K) at 31 K. The origin of the large magnetic entropy change of GdNi5 nanoparticles is ascribed to its high atomic moments and small anisotropy energy barrier induced by its small particle size.展开更多
基金This work was supported by grants from the National Natural Science Foundation of China to Z Tu(31902307)National Key Research and Development Program of China to C Tu(2017YFD0500104)Wildlife Borne Infectious Diseases Monitoring Project of the State Forestry and Grassland Administration of China.
文摘Four species of porcine circoviruses(PCV1–4)have been reported to circulate in Chinese domestic pigs,while the epizootiology of these viruses in free-ranging wild boars in China remains unknown.In this study,tissue and serum samples collected from diseased or apparently healthy wild boars between 2018 and 2020 in 19 regions of China were tested for the prevalence of PCV1–4 infections.Positive rates of PCV1,PCV2,and PCV3 DNA in the tissue samples of Chinese wild boars were 1.6%(4/247),58.3%(144/247),and 10.9%(27/247)respectively,with none positive for PCV4.Sequence analysis of viral genome showed that the four PCV1 strains distributed in Hunan and Inner Mongolia shared 97.5%–99.6%sequence identity with global distributed reference strains.Comparison of the ORF2 gene sequences showed that 80 PCV2 strains widely distributed in 18 regions shared 79.5%–100%sequence identity with reference strains from domestic pigs and wild boars,and were grouped into PCV2a(7),PCV2b(31)and PCV2d(42).For PCV3,17 sequenced strains shared 97.2%–100%nucleotide identity at the genomic level and could be divided into PCV3a(3),PCV3b(2)and PCV3c(12)based on the phylogeny of ORF2 gene sequences.Serological data revealed antibody positive rates against PCV1 and PCV2 of 11.4%(19/167)and 53.9%(90/167)respectively.The data obtained in this study improved our understanding about the epidemiological situations of PCVs infection in free-ranging wild boars in China and will be valuable for the prevention and control of diseases caused by PCVs infection.
基金supported by the National Natural Science Foundation of China(Nos.50901078 and 51271178)the National High Technology Research and Development Program (No.2011AA03A402) of Chinathe National High Technology Research and Development Program of China("863 Program",No.2011AA03A402)
文摘GdNi5 nanoparticles and GdNis/Gd2O3 nanocapsules (with GdNi5 core and Gd2O3 shell) were prepared by arcdischarge technique under different hydrogen partial pressure. The GdNi5 nanoparticles show irregular spherical shape and have a size distribution of 10-50 nm with an average diameter of 15 nm. In comparison, the GdNi5/Gd2O3 nanocapsules present spherical morphology and show a size distribution of 10-100 nm with an average diameter of 60 nm. Under a magnetic field change of 50 kOe, the maximum magnetic entropy change of GdNi5 nanoparticles is 13.5 J/(kg K) at 5 K, while the corresponding value of the GdNis/Gd2O3 nanocapsuels is only 5.7 J/(kg K) at 31 K. The origin of the large magnetic entropy change of GdNi5 nanoparticles is ascribed to its high atomic moments and small anisotropy energy barrier induced by its small particle size.