Ultra-low velocity zones(ULVZs)provide important information on the composition and dynamics of the core-mantle boundary(CMB).However,their global distribution and characteristics are not well constrained,especially n...Ultra-low velocity zones(ULVZs)provide important information on the composition and dynamics of the core-mantle boundary(CMB).However,their global distribution and characteristics are not well constrained,especially near African large low-shear velocity provinces(LLSVPs).Here,we used ScS precursor(SdS)and postcursor(ScscS)phases recorded by various seismic networks in Africa and South America to investigate the ULVZ characteristics underlying the South Atlantic Ocean.We found no evidence of ULVZs near the SE boundary of South America,but an ULVZ was found within the SW boundary of the African LLSVP,with thicknesses ranging from 11–18 km and reductions in S-wave velocities of 18%–34%.Our results,combined with the global distribution of ULVZs,suggest that thermal activity may be essential to ULVZ formation.Moreover,subducted slab and mantle flow may also play a key role,depending on the location of the ULVZs.展开更多
This study aimed to evaluate the efficacy of Chinese herbal medicine(CHM)in patients with severe/critical coronavirus disease 2019(COVID-19).In this retrospective study,data were collected from 662 patients with sever...This study aimed to evaluate the efficacy of Chinese herbal medicine(CHM)in patients with severe/critical coronavirus disease 2019(COVID-19).In this retrospective study,data were collected from 662 patients with severe/critical COVID-19 who were admitted to a designated hospital to treat patients with severe COVID-19 in Wuhan before March 20,2020.All patients were divided into an exposed group(CHM users)and a control group(non-users).After propensity score matching in a 1:1 ratio,156 CHM users were matched by propensity score to 156 non-users.No significant differences in seven baseline clinical variables were found between the two groups of patients.All-cause mortality was reported in 13 CHM users who died and 36 non-users who died.After multivariate adjustment,the mortality risk of CHM users was reduced by 82.2%(odds ratio 0.178,95%CI 0.076–0.418;P<0.001)compared with the non-users.Secondly,age(odds ratio 1.053,95%CI 1.023–1.084;P<0.001)and the proportion of severe/critical patients(odds ratio 0.063,95%CI 0.028–0.143;P<0.001)were the risk factors of mortality.These results show that the use of CHM may reduce the mortality of patients with severe/critical COVID-19.展开更多
基金supported by the National Natural Science Foundation of China(Nos.41774053 and 42074059)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(No.XDB42000000).
文摘Ultra-low velocity zones(ULVZs)provide important information on the composition and dynamics of the core-mantle boundary(CMB).However,their global distribution and characteristics are not well constrained,especially near African large low-shear velocity provinces(LLSVPs).Here,we used ScS precursor(SdS)and postcursor(ScscS)phases recorded by various seismic networks in Africa and South America to investigate the ULVZ characteristics underlying the South Atlantic Ocean.We found no evidence of ULVZs near the SE boundary of South America,but an ULVZ was found within the SW boundary of the African LLSVP,with thicknesses ranging from 11–18 km and reductions in S-wave velocities of 18%–34%.Our results,combined with the global distribution of ULVZs,suggest that thermal activity may be essential to ULVZ formation.Moreover,subducted slab and mantle flow may also play a key role,depending on the location of the ULVZs.
基金This study was approved by the institutional ethics board of Wuhan Integrated TCM and Western Medicine Hospital(No.[2020]8)and was registered with chictr.org.cn(ChiCTR2000030719)all procedures followed were in accordance with the ethical standards.
文摘This study aimed to evaluate the efficacy of Chinese herbal medicine(CHM)in patients with severe/critical coronavirus disease 2019(COVID-19).In this retrospective study,data were collected from 662 patients with severe/critical COVID-19 who were admitted to a designated hospital to treat patients with severe COVID-19 in Wuhan before March 20,2020.All patients were divided into an exposed group(CHM users)and a control group(non-users).After propensity score matching in a 1:1 ratio,156 CHM users were matched by propensity score to 156 non-users.No significant differences in seven baseline clinical variables were found between the two groups of patients.All-cause mortality was reported in 13 CHM users who died and 36 non-users who died.After multivariate adjustment,the mortality risk of CHM users was reduced by 82.2%(odds ratio 0.178,95%CI 0.076–0.418;P<0.001)compared with the non-users.Secondly,age(odds ratio 1.053,95%CI 1.023–1.084;P<0.001)and the proportion of severe/critical patients(odds ratio 0.063,95%CI 0.028–0.143;P<0.001)were the risk factors of mortality.These results show that the use of CHM may reduce the mortality of patients with severe/critical COVID-19.
