The mechanical properties of castings depend on the grain size.There is evidence that titanium and boron(Al-5Ti-1B master alloy)affect the grain size of magnesium alloys.Here,the influence of the addition of 0-1 wt.%o...The mechanical properties of castings depend on the grain size.There is evidence that titanium and boron(Al-5Ti-1B master alloy)affect the grain size of magnesium alloys.Here,the influence of the addition of 0-1 wt.%of Al-5Ti-1B master alloy on the grain size of AZ91 magnesium alloy was investigated.Melting of the alloy was performed in steel and corundum crucibles.To study the effect of cooling rate on grain size,cylindrical samples were cast in steel and fireclay molds.The Al-5Ti-1B master alloy addition did not change the phase composition of the AZ91 alloy.This study demonstrates that the addition of Al-5Ti-1B did not contribute to the grain refinement of the AZ91 alloy,but rather led to its coarsening for samples cast in both the steel and fireclay molds.Increasing the holding time after the addition of the Al-5Ti-1B master alloy from 15 to 110 minutes also did not lead to significant grain coarsening.The mechanical properties of the AZ91 alloy samples slightly improved after Al-5Ti-1B addition.展开更多
Along with the rapid advance of industrialization and urbanization process, fostering new agricultural business entities become inevitable for agricultural transformation and the construction of agricultural moderniza...Along with the rapid advance of industrialization and urbanization process, fostering new agricultural business entities become inevitable for agricultural transformation and the construction of agricultural modernization in China. The status of the new agricultural business entities determines the level of modern agricultural development. In recent years, new agricultural business entities have grew rapidly. However, there are still many problems including the difficulties in financing loans, inadequate agricultural insurance system, bad implementation of agricultural subsidies, jagged agricultural talents and so on. In order to foster new agricultural business entities, countermeasures should be carried out to ensure financial support, perfect the agricultural insurance, strengthen the level of agricultural subsidies, strive to develop the degree of specialization agricultural operators and so on.展开更多
Equine infectious anemia virus(EIAV)is a member of the lentivirus genus in the Retroviridae family and is considered an animal model for HIV/AIDS research.An attenuated EIAV vaccine,which was successfully developed in...Equine infectious anemia virus(EIAV)is a member of the lentivirus genus in the Retroviridae family and is considered an animal model for HIV/AIDS research.An attenuated EIAV vaccine,which was successfully developed in the 1970s by classical serial passage techniques,is the first and only lentivirus vaccine that has been widely used to date.Restriction factors are cellular proteins that provide an early line of defense against viral replication and spread by interfering with various critical steps in the viral replication cycle.However,viruses have evolved specific mechanisms to overcome these host barriers through adaptation.The battle between the viruses and restriction factors is actually a natural part of the viral replication process,which has been well studied in human immunodeficiency virus type 1(HIV-1).EIAV has the simplest genome composition of all lentiviruses,making it an intriguing subject for understanding how the virus employs its limited viral proteins to overcome restriction factors.In this review,we summarize the current literature on the interactions between equine restriction factors and EIAV.The features of equine restriction factors and the mechanisms by which the EIAV counteract the restriction suggest that lentiviruses employ diverse strategies to counteract innate immune restrictions.In addition,we present our insights on whether restriction factors induce alterations in the phenotype of the attenuated EIAV vaccine.展开更多
Flaviviruses are a genus of mostly arthropod-borne RNA viruses that cause a range of pathologies in humans.Basic knowledge on flaviviruses is rapidly expanding,partly due to their status as frequent emerging or re-eme...Flaviviruses are a genus of mostly arthropod-borne RNA viruses that cause a range of pathologies in humans.Basic knowledge on flaviviruses is rapidly expanding,partly due to their status as frequent emerging or re-emerging pathogens.Flaviviruses include the dengue,Zika,West Nile,tick-borne encephalitis and yellow fever viruses(DENV,ZIKV,WNV,TBEV and YFV,respectively).As is the case with other families of viruses,the success of productive infection of human cells by flaviviruses depends in part on the antiviral activity of a heterogeneous group of cellular antiviral proteins called restriction factors.Restriction factors are the effector proteins of the cell-autonomous innate response against viruses,an immune pathway that also includes virus sensors as well as intracellular and extracellular signal mediators such as type I interferons(IFN-I).In this review,I summarize recent progress toward the identification and characterization of flavivirus restriction factors.In particular,I focus on IFI6,Schlafen 11,FMRP,OAS-RNase L,RyDEN,members of the TRIM family of proteins(TRIM5α,TRIM19,TRIM56,TRIM69 and TRIM79α)and a new mechanism of action proposed for viperin.Recent and future studies on this topic will lead to a more complete picture of the flavivirus restrictome,defined as the ensemble of cellular factors with demonstrated anti-flaviviral activity.展开更多
APOBEC3G(A3G)is a host cytidine deaminase that incorporates into HIV-1 virions and efficiently inhibits viral replication.The virally encoded protein Vif binds to A3G and induces its degradation,thereby counteracting ...APOBEC3G(A3G)is a host cytidine deaminase that incorporates into HIV-1 virions and efficiently inhibits viral replication.The virally encoded protein Vif binds to A3G and induces its degradation,thereby counteracting the antiviral activity of A3G.Vif-mediated A3G degradation clearly represents a potential target for anti-HIV drug development.Currently,there is an urgent need for understanding the three dimensional structure of full-length A3G.In this work,we use a homology modeling approach to propose a structure for A3G based on the crystal structure of APOBEC2(APO2)and the catalytic domain structure of A3G.Two compounds,IMB26 and IMB35,which have been shown to bind to A3G and block degradation by Vif,were docked into the A3G model and the binding modes were generated for further analysis.The results may be used to design or optimize molecules targeting Vif–A3G interaction,and lead to the development of novel anti-HIV drugs.展开更多
Zika virus(ZIKV) infection can cause severe neurological diseases including neonatal microcephaly and GuillainBarre syndrome. Long noncoding RNAs(lncRNAs) are the by-products of the transcription process, which are co...Zika virus(ZIKV) infection can cause severe neurological diseases including neonatal microcephaly and GuillainBarre syndrome. Long noncoding RNAs(lncRNAs) are the by-products of the transcription process, which are considered to affect viral infection. However, it remains largely unexplored whether host lncRNAs play a role in ZIKV infection. Here, we identified a group of human lncRNAs that were up-regulated upon ZIKV infection and were dependent on the type I interferon(IFN) signaling. Overexpression of lncRNA ZAP-IT1 leads to an impairment of ZIKV infection. Correspondently, deficiency of ZAP-IT1 led to an enhancement of ZIKV infection.We further confirmed that ZAP-IT1, an intronic lncRNA with total 551 nt in length, is mainly located in the nuclear upon ZIKV infection. Knockout of ZAP-IT1 also led to the increase of dengue virus(DENV), Japanese encephalitis virus(JEV), or vesicular stomatitis virus(VSV) infection. Mechanically, we found that the antiviral effect of ZAP-IT1 was independent of the type I IFN signaling pathway. Therefore, our data unveiled that host lncRNA ZAP-IT1 induced by the type I IFN signaling, showed robust restriction on ZIKV infection, and even on DENV, JEV, and VSV infection, which may benefit the development of antiviral therapeutics.展开更多
文摘The mechanical properties of castings depend on the grain size.There is evidence that titanium and boron(Al-5Ti-1B master alloy)affect the grain size of magnesium alloys.Here,the influence of the addition of 0-1 wt.%of Al-5Ti-1B master alloy on the grain size of AZ91 magnesium alloy was investigated.Melting of the alloy was performed in steel and corundum crucibles.To study the effect of cooling rate on grain size,cylindrical samples were cast in steel and fireclay molds.The Al-5Ti-1B master alloy addition did not change the phase composition of the AZ91 alloy.This study demonstrates that the addition of Al-5Ti-1B did not contribute to the grain refinement of the AZ91 alloy,but rather led to its coarsening for samples cast in both the steel and fireclay molds.Increasing the holding time after the addition of the Al-5Ti-1B master alloy from 15 to 110 minutes also did not lead to significant grain coarsening.The mechanical properties of the AZ91 alloy samples slightly improved after Al-5Ti-1B addition.
基金Supported by the National Social Science Fund(13CJY079)the National Natural Science Fund(71303039)
文摘Along with the rapid advance of industrialization and urbanization process, fostering new agricultural business entities become inevitable for agricultural transformation and the construction of agricultural modernization in China. The status of the new agricultural business entities determines the level of modern agricultural development. In recent years, new agricultural business entities have grew rapidly. However, there are still many problems including the difficulties in financing loans, inadequate agricultural insurance system, bad implementation of agricultural subsidies, jagged agricultural talents and so on. In order to foster new agricultural business entities, countermeasures should be carried out to ensure financial support, perfect the agricultural insurance, strengthen the level of agricultural subsidies, strive to develop the degree of specialization agricultural operators and so on.
基金supported by grants from the National Natural Science Foundation of China (32172831 and 31672578 to XF.W,32170169 to X.W)the Postdoctoral Scientific Research Developmental Fund of Heilongjiang Province (LBH-Q20059 to XF.W)the Central Public-interest Scientific Institution Basal Research Fund (1610302022007 to XF.W).
文摘Equine infectious anemia virus(EIAV)is a member of the lentivirus genus in the Retroviridae family and is considered an animal model for HIV/AIDS research.An attenuated EIAV vaccine,which was successfully developed in the 1970s by classical serial passage techniques,is the first and only lentivirus vaccine that has been widely used to date.Restriction factors are cellular proteins that provide an early line of defense against viral replication and spread by interfering with various critical steps in the viral replication cycle.However,viruses have evolved specific mechanisms to overcome these host barriers through adaptation.The battle between the viruses and restriction factors is actually a natural part of the viral replication process,which has been well studied in human immunodeficiency virus type 1(HIV-1).EIAV has the simplest genome composition of all lentiviruses,making it an intriguing subject for understanding how the virus employs its limited viral proteins to overcome restriction factors.In this review,we summarize the current literature on the interactions between equine restriction factors and EIAV.The features of equine restriction factors and the mechanisms by which the EIAV counteract the restriction suggest that lentiviruses employ diverse strategies to counteract innate immune restrictions.In addition,we present our insights on whether restriction factors induce alterations in the phenotype of the attenuated EIAV vaccine.
文摘Flaviviruses are a genus of mostly arthropod-borne RNA viruses that cause a range of pathologies in humans.Basic knowledge on flaviviruses is rapidly expanding,partly due to their status as frequent emerging or re-emerging pathogens.Flaviviruses include the dengue,Zika,West Nile,tick-borne encephalitis and yellow fever viruses(DENV,ZIKV,WNV,TBEV and YFV,respectively).As is the case with other families of viruses,the success of productive infection of human cells by flaviviruses depends in part on the antiviral activity of a heterogeneous group of cellular antiviral proteins called restriction factors.Restriction factors are the effector proteins of the cell-autonomous innate response against viruses,an immune pathway that also includes virus sensors as well as intracellular and extracellular signal mediators such as type I interferons(IFN-I).In this review,I summarize recent progress toward the identification and characterization of flavivirus restriction factors.In particular,I focus on IFI6,Schlafen 11,FMRP,OAS-RNase L,RyDEN,members of the TRIM family of proteins(TRIM5α,TRIM19,TRIM56,TRIM69 and TRIM79α)and a new mechanism of action proposed for viperin.Recent and future studies on this topic will lead to a more complete picture of the flavivirus restrictome,defined as the ensemble of cellular factors with demonstrated anti-flaviviral activity.
基金part by 973 program(2012C B911102)the National S&T Major Special Project on Major New Drug Innovation(2012ZX09102101-018)the National S&T International Collaboration 2010DFA31580(J.D.J.)and 2010DFB30870(Q.J.).
文摘APOBEC3G(A3G)is a host cytidine deaminase that incorporates into HIV-1 virions and efficiently inhibits viral replication.The virally encoded protein Vif binds to A3G and induces its degradation,thereby counteracting the antiviral activity of A3G.Vif-mediated A3G degradation clearly represents a potential target for anti-HIV drug development.Currently,there is an urgent need for understanding the three dimensional structure of full-length A3G.In this work,we use a homology modeling approach to propose a structure for A3G based on the crystal structure of APOBEC2(APO2)and the catalytic domain structure of A3G.Two compounds,IMB26 and IMB35,which have been shown to bind to A3G and block degradation by Vif,were docked into the A3G model and the binding modes were generated for further analysis.The results may be used to design or optimize molecules targeting Vif–A3G interaction,and lead to the development of novel anti-HIV drugs.
基金supported by National Natural Science Foundation of China,China(No.31970887)Guangdong Science and Technology Department,China(No.2018B030337001)Guangdong Basic and Applied Basic Foundation(No.2019A1515011336)
文摘Zika virus(ZIKV) infection can cause severe neurological diseases including neonatal microcephaly and GuillainBarre syndrome. Long noncoding RNAs(lncRNAs) are the by-products of the transcription process, which are considered to affect viral infection. However, it remains largely unexplored whether host lncRNAs play a role in ZIKV infection. Here, we identified a group of human lncRNAs that were up-regulated upon ZIKV infection and were dependent on the type I interferon(IFN) signaling. Overexpression of lncRNA ZAP-IT1 leads to an impairment of ZIKV infection. Correspondently, deficiency of ZAP-IT1 led to an enhancement of ZIKV infection.We further confirmed that ZAP-IT1, an intronic lncRNA with total 551 nt in length, is mainly located in the nuclear upon ZIKV infection. Knockout of ZAP-IT1 also led to the increase of dengue virus(DENV), Japanese encephalitis virus(JEV), or vesicular stomatitis virus(VSV) infection. Mechanically, we found that the antiviral effect of ZAP-IT1 was independent of the type I IFN signaling pathway. Therefore, our data unveiled that host lncRNA ZAP-IT1 induced by the type I IFN signaling, showed robust restriction on ZIKV infection, and even on DENV, JEV, and VSV infection, which may benefit the development of antiviral therapeutics.
