Ultrashort and powerful laser interactions with a target generate intense wideband electromagnetic pulses(EMPs).In this study,we report EMPs generated by the interactions between petawatt(30 fs,1.4×10^(20) W/cm^(...Ultrashort and powerful laser interactions with a target generate intense wideband electromagnetic pulses(EMPs).In this study,we report EMPs generated by the interactions between petawatt(30 fs,1.4×10^(20) W/cm^(2))femtosecond(fs)lasers with metal flat,plastic flat,and plastic nanowire-array(NWA)targets.Detailed analyses are conducted on the EMPs in terms of their spatial distribution,time and frequency domains,radiation energy,and protection.The results indicate that EMPs from metal targets exhibit larger amplitudes at varying angles than those generated by other types of targets and are enhanced significantly for NWA targets.Using a plastic target holder and increasing the laser focal spot can significantly decrease the radiation energy of the EMPs.Moreover,the composite shielding materials indicate an effective shielding effect against EMPs.The simulation results show that the NWA targets exert a collimating effect on thermal electrons,which directly affects the distribution of EMPs.This study provides guidance for regulating EMPs by controlling the laser focal spot,target parameters,and target rod material and is beneficial for electromagnetic-shielding design.展开更多
Objective To study the protective effect and mechanism of Shuxuetong on gerbil brain tissue from the area of ischemia-reperfusion. Methods Cerebral ischemia-reperfusion animal model by transient clipping bilateral com...Objective To study the protective effect and mechanism of Shuxuetong on gerbil brain tissue from the area of ischemia-reperfusion. Methods Cerebral ischemia-reperfusion animal model by transient clipping bilateral common carotid arteries in gerbils. Pathological changes in the hippocampal tissue were observed at different reperfusion time (12h, 3d, 7d). The expression levels of GABA and TNF-α in the hippocampal CA_1 subfield were observed using immunohistochemitry at 12 h, 3 d after reperfusion. The difference of above indices among false operation group, ischemia-reperfusion group and treatment group were compared. Results The injuries of pathology to hippocampal area in isehemiareperfusion group were more serious than treatment group. The expression levels of GABA in treatment group were significantly increased compared with ischemia-reperfusion group, but the expression levels of TNF-α between the two groups have no difference. Conclusion Shuxuetong has protective effect on brain tissue of ischemia-reperfusion by enhancing the expression of GABA in the hippocampal tissue.展开更多
AIM:To investigate the prevalence of nature tyrosinemethionine-aspartic acid-aspartic acid motif mutations in chronic hepatitis B(CHB)patients and to evaluate the efficacy of lamivudine.METHODS:A total of 1268 CHB pat...AIM:To investigate the prevalence of nature tyrosinemethionine-aspartic acid-aspartic acid motif mutations in chronic hepatitis B(CHB)patients and to evaluate the efficacy of lamivudine.METHODS:A total of 1268 CHB patients were recruited from the outpatient and inpatient departments of six centers.Tyrosine-methionine-aspartic acid-aspartic acid(YMDD)mutations were analyzed using the hepatitis B virus(HBV)drug resistance line probe assay.Forty voluntary patients were selected from those with positive or negative natural YMDD mutations to undergo treatment with lamivudine.RESULTS:YMDD mutations were detected in 288(22.71%)of the 1268 CHB patients.Multivariate analysis revealed that the patients’HBV DNA level(P=0.0282)and hepatitis B e antigen status(P=0.0133)were also associated with natural YMDD mutations.The rates of normalization of alanine aminotransferase levels and HBV DNA nondetection at 6,24,36,and 48 wk were compared between the patients with natural YMDD mutations and those without,and the differences were not significant.However,there was a significant difference in the cumulative emergence rates of virological breakthrough at 48 wk in the patients with natural YMDD mutations and those without(32.5%vs 12.5%,P=0.032).CONCLUSION:Naturally occurring YMDD mutationsare detectable in a large proportion of CHB patients;breakthrough hepatitis tended to occur in patients with natural YMDD mutations.展开更多
基金This work was supported by the National Natural Science Foundation of China(Nos.12122501,11975037,61631001,and 11921006)the National Grand Instrument Project(Nos.2019YFF01014400,2019YFF01014404)the Foundation of Science and Technology on Plasma Physics Laboratory(No.6142A04220108).
文摘Ultrashort and powerful laser interactions with a target generate intense wideband electromagnetic pulses(EMPs).In this study,we report EMPs generated by the interactions between petawatt(30 fs,1.4×10^(20) W/cm^(2))femtosecond(fs)lasers with metal flat,plastic flat,and plastic nanowire-array(NWA)targets.Detailed analyses are conducted on the EMPs in terms of their spatial distribution,time and frequency domains,radiation energy,and protection.The results indicate that EMPs from metal targets exhibit larger amplitudes at varying angles than those generated by other types of targets and are enhanced significantly for NWA targets.Using a plastic target holder and increasing the laser focal spot can significantly decrease the radiation energy of the EMPs.Moreover,the composite shielding materials indicate an effective shielding effect against EMPs.The simulation results show that the NWA targets exert a collimating effect on thermal electrons,which directly affects the distribution of EMPs.This study provides guidance for regulating EMPs by controlling the laser focal spot,target parameters,and target rod material and is beneficial for electromagnetic-shielding design.
文摘Objective To study the protective effect and mechanism of Shuxuetong on gerbil brain tissue from the area of ischemia-reperfusion. Methods Cerebral ischemia-reperfusion animal model by transient clipping bilateral common carotid arteries in gerbils. Pathological changes in the hippocampal tissue were observed at different reperfusion time (12h, 3d, 7d). The expression levels of GABA and TNF-α in the hippocampal CA_1 subfield were observed using immunohistochemitry at 12 h, 3 d after reperfusion. The difference of above indices among false operation group, ischemia-reperfusion group and treatment group were compared. Results The injuries of pathology to hippocampal area in isehemiareperfusion group were more serious than treatment group. The expression levels of GABA in treatment group were significantly increased compared with ischemia-reperfusion group, but the expression levels of TNF-α between the two groups have no difference. Conclusion Shuxuetong has protective effect on brain tissue of ischemia-reperfusion by enhancing the expression of GABA in the hippocampal tissue.
基金Supported by Zhenjiang Municipal Science and Technology Commission,No.SH2009016
文摘AIM:To investigate the prevalence of nature tyrosinemethionine-aspartic acid-aspartic acid motif mutations in chronic hepatitis B(CHB)patients and to evaluate the efficacy of lamivudine.METHODS:A total of 1268 CHB patients were recruited from the outpatient and inpatient departments of six centers.Tyrosine-methionine-aspartic acid-aspartic acid(YMDD)mutations were analyzed using the hepatitis B virus(HBV)drug resistance line probe assay.Forty voluntary patients were selected from those with positive or negative natural YMDD mutations to undergo treatment with lamivudine.RESULTS:YMDD mutations were detected in 288(22.71%)of the 1268 CHB patients.Multivariate analysis revealed that the patients’HBV DNA level(P=0.0282)and hepatitis B e antigen status(P=0.0133)were also associated with natural YMDD mutations.The rates of normalization of alanine aminotransferase levels and HBV DNA nondetection at 6,24,36,and 48 wk were compared between the patients with natural YMDD mutations and those without,and the differences were not significant.However,there was a significant difference in the cumulative emergence rates of virological breakthrough at 48 wk in the patients with natural YMDD mutations and those without(32.5%vs 12.5%,P=0.032).CONCLUSION:Naturally occurring YMDD mutationsare detectable in a large proportion of CHB patients;breakthrough hepatitis tended to occur in patients with natural YMDD mutations.
