The liquid quenching method was adopted to study the solidification morphology and microstructure of AZglD Mg alloy in semisolid. The results indicate that cooling rate has important effects upon the solidification st...The liquid quenching method was adopted to study the solidification morphology and microstructure of AZglD Mg alloy in semisolid. The results indicate that cooling rate has important effects upon the solidification structures. Under the cooling rate of liquid quenching, primary α-phase grows first by attaching on the original α grains, or independent nucleation and growth. The high cooling rate makes primary α-phase grow in ＂rags＂ or dendrite shape. Eutectic solidification is carried out in terms of both dissociated growth and symbiotic growth. The dissociated growth forms rough and large β-phase at grain boundaries, while symbiotic growth forms eutectic of laminar structure. The small liquid pool inside the original α-phase solidifies basically in the same way as that of intergranular liquid, but owing to less amount of liquid phase, the eutectic solidification is mainly carried out in the dissociated pattern.展开更多
A new species,Berberis viridiflora X.H.Li,and a new variety,Berberis sanguinea Franch.var.viridisepala X.H.Li,L.C.Zhang & W.H.Li are described and illustrated from Baoxing County,a biodiversity hotspot located on ...A new species,Berberis viridiflora X.H.Li,and a new variety,Berberis sanguinea Franch.var.viridisepala X.H.Li,L.C.Zhang & W.H.Li are described and illustrated from Baoxing County,a biodiversity hotspot located on the eastern edge of Hengduan Mountains in Sichuan Province,Southwest China,Both new taxa resemble B.sanguinea Franch.var.sanguinea,but B.viridiflora differs by the greenish flowers,and the petals being truncate,obtuse,or undulate at apex;while B.sanguinea var.viridisepala differs by the greenish or yellowish green flowers.Morphological features of the pollen grains of B.sanguinea and the two new taxa are revealed by scanning election microscope.B.sanguinea var.sanguinea displays obvious similarities with a sympatric congener,Berberis multiovula T.S.Ying in the morphology of flowers,stems and leaves,especially its ovule number varies greatly from 2 to 9,thus,B.multiovula characterized by the5-ovuled ovary is reduced to a synonymy of B.sanguinea var.sanguinea.On the basis of field surveys and study of herbarium specimens,a total of 16 species and varieties of Berberis are recorded from Baoxing County,and a key is provided.Among the 16 taxa,most phenotypic variations in Chinese Berberis can be displayed,including the habit of plants,most morphological variations of stems,branches and leaves,all types of inflorescences,all color types of flowers,and nearly all types of the shape and color of fruits.Baoxing County and its adjacent Sichuan Giant Panda Sanctuaries possibly constitute an active diversification center of Berberis in eastern Hengduan Mountains of China.展开更多
Human immunodeficiency virus(HIV) attacks human immune system and causes life-threatening acquired immune deficiency syndrome(AIDS). Treatment with combination antiretroviral therapy(cART) could inhibit virus growth a...Human immunodeficiency virus(HIV) attacks human immune system and causes life-threatening acquired immune deficiency syndrome(AIDS). Treatment with combination antiretroviral therapy(cART) could inhibit virus growth and slow progression of the disease, however, at the same time posing various adverse effects. Host ubiquitin-proteasome pathway(UPP) plays important roles in host immunity against pathogens including viruses by inducing degradation of viral proteins. Previously a series of methods for retargeting substrates for ubiquitin-proteasome degradation have been successfully established. In this study, we attempted to design and construct artificial chimeric ubiquitin ligases(E3 s) based on known human E3 s in order to manually target HIV-1 integrase for ubiquitin proteasome pathway-mediated degradation.Herein, a series of prototypical chimeric E3 s have been designed and constructed, and original substrate-binding domains of these E3 s were replaced with host protein domains which interacted with viral proteins. After functional assessment screening, 146 LI was identified as a functional chimeric E3 for HIV-1 NL4-3 integrase. 146 LI was then further optimized to generate 146 LIS(146 LI short) which has been shown to induce Lys48-specific polyubiquitination and reduce protein level of HIV-1 NL4-3 integrase more effectively in cells. Lymphocyte cells with 146 LIS knock-in generated by CRISPR/Cas-mediated homology-directed repair(HDR) showed remarkably decreased integration of HIV-1 NL4-3 viral DNAs and reduced viral replication without obvious cell cytotoxicity. Our study successfully obtained an artificial chimeric E3 which can induce Lys48-specific polyubiquitination and proteasome-mediated degradation of HIV-1 NL4-3 integrase, thus effectively inhibiting viral DNA integration and viral replication upon virus infection.展开更多
文摘The liquid quenching method was adopted to study the solidification morphology and microstructure of AZglD Mg alloy in semisolid. The results indicate that cooling rate has important effects upon the solidification structures. Under the cooling rate of liquid quenching, primary α-phase grows first by attaching on the original α grains, or independent nucleation and growth. The high cooling rate makes primary α-phase grow in ＂rags＂ or dendrite shape. Eutectic solidification is carried out in terms of both dissociated growth and symbiotic growth. The dissociated growth forms rough and large β-phase at grain boundaries, while symbiotic growth forms eutectic of laminar structure. The small liquid pool inside the original α-phase solidifies basically in the same way as that of intergranular liquid, but owing to less amount of liquid phase, the eutectic solidification is mainly carried out in the dissociated pattern.
基金supported by the National Natural Science Foundation of China(Grant No.31170174)the S&T Basic Work,Ministry of Science and Technology of the People's Republic of China(Grant No.2013FY112100)
文摘A new species,Berberis viridiflora X.H.Li,and a new variety,Berberis sanguinea Franch.var.viridisepala X.H.Li,L.C.Zhang & W.H.Li are described and illustrated from Baoxing County,a biodiversity hotspot located on the eastern edge of Hengduan Mountains in Sichuan Province,Southwest China,Both new taxa resemble B.sanguinea Franch.var.sanguinea,but B.viridiflora differs by the greenish flowers,and the petals being truncate,obtuse,or undulate at apex;while B.sanguinea var.viridisepala differs by the greenish or yellowish green flowers.Morphological features of the pollen grains of B.sanguinea and the two new taxa are revealed by scanning election microscope.B.sanguinea var.sanguinea displays obvious similarities with a sympatric congener,Berberis multiovula T.S.Ying in the morphology of flowers,stems and leaves,especially its ovule number varies greatly from 2 to 9,thus,B.multiovula characterized by the5-ovuled ovary is reduced to a synonymy of B.sanguinea var.sanguinea.On the basis of field surveys and study of herbarium specimens,a total of 16 species and varieties of Berberis are recorded from Baoxing County,and a key is provided.Among the 16 taxa,most phenotypic variations in Chinese Berberis can be displayed,including the habit of plants,most morphological variations of stems,branches and leaves,all types of inflorescences,all color types of flowers,and nearly all types of the shape and color of fruits.Baoxing County and its adjacent Sichuan Giant Panda Sanctuaries possibly constitute an active diversification center of Berberis in eastern Hengduan Mountains of China.
基金supported by Grants from the National Science and Technology Major Project of China (2014ZX10001003)National Natural Science Foundation of China (#81620108020 & #31400774)。
文摘Human immunodeficiency virus(HIV) attacks human immune system and causes life-threatening acquired immune deficiency syndrome(AIDS). Treatment with combination antiretroviral therapy(cART) could inhibit virus growth and slow progression of the disease, however, at the same time posing various adverse effects. Host ubiquitin-proteasome pathway(UPP) plays important roles in host immunity against pathogens including viruses by inducing degradation of viral proteins. Previously a series of methods for retargeting substrates for ubiquitin-proteasome degradation have been successfully established. In this study, we attempted to design and construct artificial chimeric ubiquitin ligases(E3 s) based on known human E3 s in order to manually target HIV-1 integrase for ubiquitin proteasome pathway-mediated degradation.Herein, a series of prototypical chimeric E3 s have been designed and constructed, and original substrate-binding domains of these E3 s were replaced with host protein domains which interacted with viral proteins. After functional assessment screening, 146 LI was identified as a functional chimeric E3 for HIV-1 NL4-3 integrase. 146 LI was then further optimized to generate 146 LIS(146 LI short) which has been shown to induce Lys48-specific polyubiquitination and reduce protein level of HIV-1 NL4-3 integrase more effectively in cells. Lymphocyte cells with 146 LIS knock-in generated by CRISPR/Cas-mediated homology-directed repair(HDR) showed remarkably decreased integration of HIV-1 NL4-3 viral DNAs and reduced viral replication without obvious cell cytotoxicity. Our study successfully obtained an artificial chimeric E3 which can induce Lys48-specific polyubiquitination and proteasome-mediated degradation of HIV-1 NL4-3 integrase, thus effectively inhibiting viral DNA integration and viral replication upon virus infection.
