A recently released XMM-Newton note revealed a significant calibration issue between nuclear spectroscopic telescope array(NuSTAR)and XMM-Newton European Photon Imaging Camera(EPIC)and provided an empirical correction...A recently released XMM-Newton note revealed a significant calibration issue between nuclear spectroscopic telescope array(NuSTAR)and XMM-Newton European Photon Imaging Camera(EPIC)and provided an empirical correction to the EPIC effective area.To quantify the bias caused by the calibration issue in the joint analysis of XMM-NuSTAR spectra and verify the effectiveness of the correction,in this work,we perform joint-fitting of the NuSTAR and EPIC-pn spectra for a large sample of 104 observation pairs of 44 X-ray bright active galactic nuclei(AGN).The spectra were extracted after requiring perfect simultaneity between the XMM-Newton and NuSTAR exposures(merging good time intervals(GTIs)from two missions)to avoid bias due to the rapid spectral variability of the AGN.Before the correction,the EPIC-pn spectra are systematically harder than the corresponding NuSTAR spectra by■subsequently yielding significantly underestimated cutoff energy E_(cut)and the strength of reflection component R when performing joint-fitting.We confirm that the correction is highly effective and can commendably erase the discrepancy in best-fitΓ,E_(cut),and R.We thus urge the community to apply the correction when joint-fitting XMM-NuSTAR spectra,but note that the correction is limited to 3–12 keV and therefore not applicable when the soft X-ray band data are included.Besides,we show that as merging GTIs from two missions would cause severe loss of NuSTAR net exposure time,in many cases,joint-fitting yields no advantage compared with utilizing NuSTAR data alone.Finally,We present a technical note on filtering periods of high background flares for XMM-Newton EPIC-pn exposures in the small window(SW)mode.展开更多
Nucleation of dendritic primaryα（Al） phase with addition of element Ce and Sr in hypoeutectic Al-7%Si-Mg cast alloy was investigated by using differential scanning calorimetry （DSC） and scanning electron microsco...Nucleation of dendritic primaryα（Al） phase with addition of element Ce and Sr in hypoeutectic Al-7%Si-Mg cast alloy was investigated by using differential scanning calorimetry （DSC） and scanning electron microscopy. DSC results were used to calculate the activation energy and nucleation work of primaryα（Al） phase. The results show that the values of activation energy and nucleation work are decreased and the nucleation frequency is increased with the additions of Ce and Sr to the alloys. Moreover, the grain size of dendriticα（Al） phase is well refined, and the nucleation temperatures of primaryα（Al） dendrites are decreased with the additions of Ce and Sr. The effects of elements Ce and Sr additions on kinetic nucleation of primary α（Al） phases were also discussed in hypoeutectic Al-7%Si-Mg cast alloy.展开更多
Curcin, a ribosome-inactivating protein with a molecular weight of about 28.2 kD, which strongly inhibits the protein synthesis in rabbit reticulocyte lysate system with an IC50 value of about (0.19 +/- 0.01) nmol/L, ...Curcin, a ribosome-inactivating protein with a molecular weight of about 28.2 kD, which strongly inhibits the protein synthesis in rabbit reticulocyte lysate system with an IC50 value of about (0.19 +/- 0.01) nmol/L, was purified from the seeds of Jatropha curcas L. The protein has the activity of rRNA N-glycosidase. Degenerate primers were designed based on the N-terminal partial sequence from purified curcin. The full-length curcin cDNA by RT-PCR and 5'-RACE was cloned. The deduced amino acids sequence indicates that a preprotein with 20 amino acid residues is first translated and then processed to a mature protein with 251 amino acids. The deduced amino acids sequence shares homology of 33% and 57% to those of type I ribosome-inactivating proteins (RIPs) and A chain of type II RIPs, respectively. The sequence encoding mature curcin was integrated into the pQE-30 vector for expression in Escherichia coli strain M15 (pREP4). The purified recombinant curcin was able to inhibit protein synthesis in rabbit reticulocyte lysate system.展开更多
基金supported by the National Natural Science Foundation of China(12033006,12192221,123B2042).
文摘A recently released XMM-Newton note revealed a significant calibration issue between nuclear spectroscopic telescope array(NuSTAR)and XMM-Newton European Photon Imaging Camera(EPIC)and provided an empirical correction to the EPIC effective area.To quantify the bias caused by the calibration issue in the joint analysis of XMM-NuSTAR spectra and verify the effectiveness of the correction,in this work,we perform joint-fitting of the NuSTAR and EPIC-pn spectra for a large sample of 104 observation pairs of 44 X-ray bright active galactic nuclei(AGN).The spectra were extracted after requiring perfect simultaneity between the XMM-Newton and NuSTAR exposures(merging good time intervals(GTIs)from two missions)to avoid bias due to the rapid spectral variability of the AGN.Before the correction,the EPIC-pn spectra are systematically harder than the corresponding NuSTAR spectra by■subsequently yielding significantly underestimated cutoff energy E_(cut)and the strength of reflection component R when performing joint-fitting.We confirm that the correction is highly effective and can commendably erase the discrepancy in best-fitΓ,E_(cut),and R.We thus urge the community to apply the correction when joint-fitting XMM-NuSTAR spectra,but note that the correction is limited to 3–12 keV and therefore not applicable when the soft X-ray band data are included.Besides,we show that as merging GTIs from two missions would cause severe loss of NuSTAR net exposure time,in many cases,joint-fitting yields no advantage compared with utilizing NuSTAR data alone.Finally,We present a technical note on filtering periods of high background flares for XMM-Newton EPIC-pn exposures in the small window(SW)mode.
基金Project (42-QP-009) support by Research Fund of the State Key Laboratory of Solidification Processing,ChinaProject (B08040) supported by the Program of Introducing Talents of Discipline to Universities ("111"Project),China
文摘Nucleation of dendritic primaryα（Al） phase with addition of element Ce and Sr in hypoeutectic Al-7%Si-Mg cast alloy was investigated by using differential scanning calorimetry （DSC） and scanning electron microscopy. DSC results were used to calculate the activation energy and nucleation work of primaryα（Al） phase. The results show that the values of activation energy and nucleation work are decreased and the nucleation frequency is increased with the additions of Ce and Sr to the alloys. Moreover, the grain size of dendriticα（Al） phase is well refined, and the nucleation temperatures of primaryα（Al） dendrites are decreased with the additions of Ce and Sr. The effects of elements Ce and Sr additions on kinetic nucleation of primary α（Al） phases were also discussed in hypoeutectic Al-7%Si-Mg cast alloy.
文摘Curcin, a ribosome-inactivating protein with a molecular weight of about 28.2 kD, which strongly inhibits the protein synthesis in rabbit reticulocyte lysate system with an IC50 value of about (0.19 +/- 0.01) nmol/L, was purified from the seeds of Jatropha curcas L. The protein has the activity of rRNA N-glycosidase. Degenerate primers were designed based on the N-terminal partial sequence from purified curcin. The full-length curcin cDNA by RT-PCR and 5'-RACE was cloned. The deduced amino acids sequence indicates that a preprotein with 20 amino acid residues is first translated and then processed to a mature protein with 251 amino acids. The deduced amino acids sequence shares homology of 33% and 57% to those of type I ribosome-inactivating proteins (RIPs) and A chain of type II RIPs, respectively. The sequence encoding mature curcin was integrated into the pQE-30 vector for expression in Escherichia coli strain M15 (pREP4). The purified recombinant curcin was able to inhibit protein synthesis in rabbit reticulocyte lysate system.
