The special GRB 130310 A was observed by Fermi Gamma-Ray Burst Monitor and Large Area Telescope,with T90~2.4 s.With a combination of a Band function and a blackbody(BB)function,the time-resolved spectral analysis of G...The special GRB 130310 A was observed by Fermi Gamma-Ray Burst Monitor and Large Area Telescope,with T90~2.4 s.With a combination of a Band function and a blackbody(BB)function,the time-resolved spectral analysis of GRB 130310 A confirmed that there is a sub-dominate thermal component in the early period(e.g.,slice T0+[4.03-4.14]s)spectrum with BB temperature(kT)being~7~5 keV,which can be interpreted as photosphere emission.The precursor of GRB 130310 A can be fitted well with a BB component with kT~45 keV,which is higher than that of the main burst.It suggests that the radiation of GRB 130310 A is in transition from thermal to non-thermal.Such a transition is an indication of the change in jet composition from a fireball to a Poynting-flux-dominated jet.A very high peak energy is obtained in the first time bin,with the peak energy E_(p) of the Band component for Band+BB and Band model being~8.5~5.2 MeV and~11.1~7.4 MeV,respectively.Afterwards,the E_(p) drops to~1 MeV.The E_(p) evolution patterns with respect to the pulses in the GRB 130310 A light curves show a hard-to-soft evolution.The interpretation of the high peak energy E_(p) within the photosphere and internal shock model is difficult.It also suggests that at least for some bursts,the Band component must invoke a non-thermal origin in the optically thin region of a GRB outflow.Assuming the redshift is z~0.1~8,the radius of the jet base r_(0)~10^(9) cm to allow(1+σ_(15))>1 in line with the calculation results of the magnetization parameter at~1015 cm(σ_(15)).However,the value of(1+σ_(15))is■1 in the zone z around 3 for r_(0)~10^(9) cm,suggesting the non-excluded possibility that the origin is from ICMART with a low value.The photosphere-internal shock seems capable of interpreting the high peak energy,which requires electron Lorentz factorγe~60 andεe~0.06.展开更多
Neuraminidase(NA) plays a biologically vital role in the replication of influenza virus, and NA inhibitors(NAIs) are most widely used in the clinical anti-flu therapy. NA of 2009 H1 N1 influenza virus(09 N1) possesses...Neuraminidase(NA) plays a biologically vital role in the replication of influenza virus, and NA inhibitors(NAIs) are most widely used in the clinical anti-flu therapy. NA of 2009 H1 N1 influenza virus(09 N1) possesses a different substrate-binding cavity compared with other NA subtypes, making 09 N1 a more appropriate starting point for the discovery of potent 09 N1 inhibitors. As natural products are of great structural diversity, research on the interaction between natural NAIs and 09 N1 can throw light on the design of new structural NAIs. In this study, we, for the first time, conducted molecular docking procedure with GOLD on 10 natural inhibitors to 09 N1, and acquired their binding modes with 09 N1. The docking results showed that the active site S1 was important in the binding of NAIs to 09 N1. Then five scaffolds were extracted from these NAIs with interactions to site S1, and these could be used in the structural modification of NAIs. Besides, we found that the addition of H-bonding interaction with the active site could improve the NA inhibitory activity of NAIs, and it might be the reason why the approved NAIs showed high efficiency. Two terminal hydrophobic sites(Terminal 1 and Terminal 2) with no interactions to the approved NAI zanamivir were found in the 09 N1 active cavity, and four NAIs were first found to bind with the terminals. Till now, there are few studies on the meaning of Terminal 2 in the binding of NAI to NA, which could be a new direction for the rational design of NAIs.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11673006,U1938201,11533003)the Guangxi Science Foundation(Grant Nos.2016GXNSFFA380006,2017GXNSFBA198206,2017AD22006,2018GXNSFGA281007)+1 种基金the OneHundred-Talents Program of Guangxi collegesHigh level innovation team and outstanding scholar program in Guangxi colleges。
文摘The special GRB 130310 A was observed by Fermi Gamma-Ray Burst Monitor and Large Area Telescope,with T90~2.4 s.With a combination of a Band function and a blackbody(BB)function,the time-resolved spectral analysis of GRB 130310 A confirmed that there is a sub-dominate thermal component in the early period(e.g.,slice T0+[4.03-4.14]s)spectrum with BB temperature(kT)being~7~5 keV,which can be interpreted as photosphere emission.The precursor of GRB 130310 A can be fitted well with a BB component with kT~45 keV,which is higher than that of the main burst.It suggests that the radiation of GRB 130310 A is in transition from thermal to non-thermal.Such a transition is an indication of the change in jet composition from a fireball to a Poynting-flux-dominated jet.A very high peak energy is obtained in the first time bin,with the peak energy E_(p) of the Band component for Band+BB and Band model being~8.5~5.2 MeV and~11.1~7.4 MeV,respectively.Afterwards,the E_(p) drops to~1 MeV.The E_(p) evolution patterns with respect to the pulses in the GRB 130310 A light curves show a hard-to-soft evolution.The interpretation of the high peak energy E_(p) within the photosphere and internal shock model is difficult.It also suggests that at least for some bursts,the Band component must invoke a non-thermal origin in the optically thin region of a GRB outflow.Assuming the redshift is z~0.1~8,the radius of the jet base r_(0)~10^(9) cm to allow(1+σ_(15))>1 in line with the calculation results of the magnetization parameter at~1015 cm(σ_(15)).However,the value of(1+σ_(15))is■1 in the zone z around 3 for r_(0)~10^(9) cm,suggesting the non-excluded possibility that the origin is from ICMART with a low value.The photosphere-internal shock seems capable of interpreting the high peak energy,which requires electron Lorentz factorγe~60 andεe~0.06.
基金National Nature Science Foundation of China (Grant No. 81241114)Basic Research Project of Logistics University of PAP (Grant No. WHJ201401)Fund for Scientific Research and Innovation Team of Logistics University of PAP。
文摘Neuraminidase(NA) plays a biologically vital role in the replication of influenza virus, and NA inhibitors(NAIs) are most widely used in the clinical anti-flu therapy. NA of 2009 H1 N1 influenza virus(09 N1) possesses a different substrate-binding cavity compared with other NA subtypes, making 09 N1 a more appropriate starting point for the discovery of potent 09 N1 inhibitors. As natural products are of great structural diversity, research on the interaction between natural NAIs and 09 N1 can throw light on the design of new structural NAIs. In this study, we, for the first time, conducted molecular docking procedure with GOLD on 10 natural inhibitors to 09 N1, and acquired their binding modes with 09 N1. The docking results showed that the active site S1 was important in the binding of NAIs to 09 N1. Then five scaffolds were extracted from these NAIs with interactions to site S1, and these could be used in the structural modification of NAIs. Besides, we found that the addition of H-bonding interaction with the active site could improve the NA inhibitory activity of NAIs, and it might be the reason why the approved NAIs showed high efficiency. Two terminal hydrophobic sites(Terminal 1 and Terminal 2) with no interactions to the approved NAI zanamivir were found in the 09 N1 active cavity, and four NAIs were first found to bind with the terminals. Till now, there are few studies on the meaning of Terminal 2 in the binding of NAI to NA, which could be a new direction for the rational design of NAIs.
