The set-net fi shery resources in Haizhou Bay,China have been over-exploited because of over-fi shing and environmental deterioration.To better understand the current situations and the development trends of fi shery ...The set-net fi shery resources in Haizhou Bay,China have been over-exploited because of over-fi shing and environmental deterioration.To better understand the current situations and the development trends of fi shery resources,the temporal change of biological characteristics and community compositions were analyzed from 2011 to 2018.Meanwhile,we evaluated the impact of the summer moratorium of marine fi shing(SMMF)on the set-net fi shery.Results show that the mean total length of the six principal species showed varying degrees of decreasing trends,while the changing patterns for the mean weight proportion of the six groups varied.For the whole communities,the similarities of the inter-annual community diversities and compositions were high.SMMF is meaningful to help reproductive success and support recruitment.Every year,the catch per unit eff orts of the six principal species after SMMF were signifi cantly higher than before SMMF except for Octopus ocellatus.The target groups showed a higher mean weight proportion after SMMF than before SMMF in eight years,while the non-target groups were converse.Therefore,the resources of the set-net fi shery are changing in the study periods;and SMMF is an important factor infl uencing biological characteristics and community structure.Despite some challenges,SMMF is still one of the most appropriate policy tools to protect the set-net fi shery resources under the reality of China.展开更多
The abnormal expansion of G-rich hexanucleotide repeat,GGGGCC(G4C2),in chromosome 9 open reading frame 72(C9orf72)is known to be the prevailing genetic cause of two fatal degenerative neurological diseases,amyotrophi...The abnormal expansion of G-rich hexanucleotide repeat,GGGGCC(G4C2),in chromosome 9 open reading frame 72(C9orf72)is known to be the prevailing genetic cause of two fatal degenerative neurological diseases,amyotrophic lateral sclerosis(ALS)and frontotemporal dementia(FTD).It is well known that the DNA G4C2 repeat expansion with different lengths can form G-quadruplexes which affect gene transcription related to ALS/FTD,therefore it is crucial to understand DNA G4C2 G-quadruplex structures.Herein,by utilizing nuclear magnetic resonance(NMR)spectroscopy,we examined DNA G-quadruplex structure adopted by two G4C2 hexanucleotide repeats with an inosine substitution at position 4,d(G4C2)2-I4.We show that d(G4C2)2-I4 folds into an eight-layer parallel tetrameric G-quadruplex containing two parallel dimeric G-quadruplexes stacking together through p-p interaction via 50-to-50 mode in solution.Each dimeric G-quadruplex unit involves two propeller loops composed of two cytosine bases.This result is consistent with the observation in the crystal structure of d(G4C2)2.Our work not only sheds light on the structural diversity of G-quadruplexes adopted by d(G4C2)n but also provides a structural basis for drug design in treatment of ALS and FTD.展开更多
Electron-phonon coupling(EPC)is a key factor for thermoelectric properties of materials.In this paper,the thermoelectric properties of zinc-blende chalcogenides(p-type)ZnS and ZnSe have been studied through full evalu...Electron-phonon coupling(EPC)is a key factor for thermoelectric properties of materials.In this paper,the thermoelectric properties of zinc-blende chalcogenides(p-type)ZnS and ZnSe have been studied through full evaluation of EPC from first-principles,including the influences on both electrical and thermal transport.We find that the polar longitudinal optical phonon scattering is the dominant mechanism for electrical transport.Due to the triple degeneracy near the valence band maximum,the inter-band scattering also has detrimental contributions to the electrical conductivities.For phonon transport,it shows that the lattice thermal conductivity can be reduced by the electron-phonon scattering significantly at high carrier concentrations(e.g.,at 300 K with 10^(21) cm^(3) of hole,the reduction is-24.9%for ZnS and-28.4%for ZnSe,respectively).Finally,the p-type thermoelectric figure of merit(ZT)of two systems have been obtained,which are 0.129 for ZnS and 0.141 for ZnSe,at 700 K with their respective optimal hole concentrations.Our work provides a complete and in-depth study of thermoelectric properties in chalcogenides ZnX from the role of EPC.The results suggest EPC plays an important role on the thermoelectric properties and thus full evaluation of EPC is necessary especially for polar materials.展开更多
基金Supported by the Argo-Scientifi c Research in the Public Interest,China(No.201203018)。
文摘The set-net fi shery resources in Haizhou Bay,China have been over-exploited because of over-fi shing and environmental deterioration.To better understand the current situations and the development trends of fi shery resources,the temporal change of biological characteristics and community compositions were analyzed from 2011 to 2018.Meanwhile,we evaluated the impact of the summer moratorium of marine fi shing(SMMF)on the set-net fi shery.Results show that the mean total length of the six principal species showed varying degrees of decreasing trends,while the changing patterns for the mean weight proportion of the six groups varied.For the whole communities,the similarities of the inter-annual community diversities and compositions were high.SMMF is meaningful to help reproductive success and support recruitment.Every year,the catch per unit eff orts of the six principal species after SMMF were signifi cantly higher than before SMMF except for Octopus ocellatus.The target groups showed a higher mean weight proportion after SMMF than before SMMF in eight years,while the non-target groups were converse.Therefore,the resources of the set-net fi shery are changing in the study periods;and SMMF is an important factor infl uencing biological characteristics and community structure.Despite some challenges,SMMF is still one of the most appropriate policy tools to protect the set-net fi shery resources under the reality of China.
基金the National Natural Science Foundation of China to C.L.(No.32071188)Guangdong Basic and Applied Basic Research Foundation to C.L.(No.2020A1515010034)+1 种基金the Research Grants Council of the Hong Kong Special Administrative Region,China to G.Z.(Project No.16103719,16101120,and 161011121,AoE/M-403-16,AOE/M-401/20)Hong Kong Branch of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)to G.Z.(Project No.SMSEGL20SC01eH)and VPRDO19RD03-6.
文摘The abnormal expansion of G-rich hexanucleotide repeat,GGGGCC(G4C2),in chromosome 9 open reading frame 72(C9orf72)is known to be the prevailing genetic cause of two fatal degenerative neurological diseases,amyotrophic lateral sclerosis(ALS)and frontotemporal dementia(FTD).It is well known that the DNA G4C2 repeat expansion with different lengths can form G-quadruplexes which affect gene transcription related to ALS/FTD,therefore it is crucial to understand DNA G4C2 G-quadruplex structures.Herein,by utilizing nuclear magnetic resonance(NMR)spectroscopy,we examined DNA G-quadruplex structure adopted by two G4C2 hexanucleotide repeats with an inosine substitution at position 4,d(G4C2)2-I4.We show that d(G4C2)2-I4 folds into an eight-layer parallel tetrameric G-quadruplex containing two parallel dimeric G-quadruplexes stacking together through p-p interaction via 50-to-50 mode in solution.Each dimeric G-quadruplex unit involves two propeller loops composed of two cytosine bases.This result is consistent with the observation in the crystal structure of d(G4C2)2.Our work not only sheds light on the structural diversity of G-quadruplexes adopted by d(G4C2)n but also provides a structural basis for drug design in treatment of ALS and FTD.
基金supported by the National Key Research and Development Program of China(No.2017YFB0701600 and 2018YFB0703600)the National Natural Science Foundation of China(Grant Nos.21703136,51761135127,and 11674211)the 111 Project D16002.J.Y.X.acknowledges the support from the Shanghai Sailing Program,China(17YF1427900)。
文摘Electron-phonon coupling(EPC)is a key factor for thermoelectric properties of materials.In this paper,the thermoelectric properties of zinc-blende chalcogenides(p-type)ZnS and ZnSe have been studied through full evaluation of EPC from first-principles,including the influences on both electrical and thermal transport.We find that the polar longitudinal optical phonon scattering is the dominant mechanism for electrical transport.Due to the triple degeneracy near the valence band maximum,the inter-band scattering also has detrimental contributions to the electrical conductivities.For phonon transport,it shows that the lattice thermal conductivity can be reduced by the electron-phonon scattering significantly at high carrier concentrations(e.g.,at 300 K with 10^(21) cm^(3) of hole,the reduction is-24.9%for ZnS and-28.4%for ZnSe,respectively).Finally,the p-type thermoelectric figure of merit(ZT)of two systems have been obtained,which are 0.129 for ZnS and 0.141 for ZnSe,at 700 K with their respective optimal hole concentrations.Our work provides a complete and in-depth study of thermoelectric properties in chalcogenides ZnX from the role of EPC.The results suggest EPC plays an important role on the thermoelectric properties and thus full evaluation of EPC is necessary especially for polar materials.
