[Objective] This study aimed to investigate the changes of the transcriptional levels of molecules associated with endogenous antigen processing and presenta- tion in porcine skin-derived dendritic cells infected with...[Objective] This study aimed to investigate the changes of the transcriptional levels of molecules associated with endogenous antigen processing and presenta- tion in porcine skin-derived dendritic cells infected with PCV2 in vivo. [Method] Healthy 40-day-old Landrace piglets were infected with porcine circovirus type 2 （PCV2） and euthanized on the 34, 7rd, 14th, 21st and 35th d post inoculation （DPI）. The porcine skin-derived dendritic cells （DCs） were collected to analyze the transcrip- tional levels of molecules （LMP7, UBP, MHC-I, calreticulin） associated with endogenous antigen processing and presentation by using real-time fluorescent quantitative PCR （real-time FQ-PCR）. [Result] The results showed that the level of LMP7 mR- NAs was reduced significantly on the 3DPI （P〈0.05）; the level of UBP mRNAs was consistently up-regulated, which increased significantly on the 21DPI and 35DPI （P〈 0.05）; the level of MHC-I mRNAs was significantly down-regulated on the 7DPI （P〈 0.05）; the level of calreticulin mRNAs was up-regulated slightly without significant dif- ference. [Conclusion] PCV2 can inhibit the endogenous antigen processing and presentation ability of porcine skin-derived DCs at early stages of infection.展开更多
The dynamic effect is a very important issue widely debated by scholars when studying the genetic and disaster-causing mechanisms of earthquake-triggered landslides.First,the dynamic effect mechanism and phenomena of ...The dynamic effect is a very important issue widely debated by scholars when studying the genetic and disaster-causing mechanisms of earthquake-triggered landslides.First,the dynamic effect mechanism and phenomena of earthquake-triggered landslides were summarized in this paper.Then,the primary types of dynamic effects were further used to interpret the Mogangling landslide in Moxi Town of Luding County,China.A field investigation,remote sensing,numerical calculation and theoretical analysis were carried out to illustrate the failure mechanism of slope rock masses affected by earthquakes.The interaction between seismic waves and slope rock masses and the induced dynamic effect of slope rock masses were primarily accounted for in the analysis.The slope topography,rock mass weathering and unloading characteristics,river erosion,regional seismogenic structure,and rock mass structure characteristics were also discussed.The results showed that the formation of the Mogangling landslide was mainly related to the high amplification effect of seismic acceleration and back slope effects,interface dynamic stress effects,and double-sided slope effects of seismic waves caused by the catastrophic Ms 7.75 Moxi Earthquake in 1786.The principles for the site and route selection of large-scale infrastructure in the planning stage and the scientific prevention of seismic geological disasters were proposed on the basis of the dynamic effect of earthquake-induced landslides.展开更多
A geologic time scale is a chronological system that separates the geological strata of a planetary body into different units in temporal sequence and shows its progressive evolution.The time scale of the Moon was est...A geologic time scale is a chronological system that separates the geological strata of a planetary body into different units in temporal sequence and shows its progressive evolution.The time scale of the Moon was established a half-century ago during the telescopic-early Apollo exploration era,using data with limited spatial coverage and resolution.The past decades have seen a wide array of studies,which have significantly extended our understanding of global lunar geologic evolution.Based on a comprehensive review of lunar evolution with respect to the dynamical changes,we propose two major updates to the current lunar time scale paradigm to include the evolution of both endogenic and exogenic dynamic forces now known to have influenced early lunar history.Firstly,based on the temporal interplay of exogenic and endogenic processes in altering the Moon,we defined three Eon/Eonothem-level units to represent three dynamical evolutionary phases.Secondly,the pre-Nectarian System is redefined and divided as the magma ocean-era Magma-oceanian System and the following Aitkenian System beginning with the South Pole-Aitken basin.The ejecta of this basin,Das Formation,was deposited on the primordial lunar crust as the oldest stratum produced from exogenic processes.The updated lunar time scale,facilitated by the post-Apollo exploration and research advances,provides an integrated framework to depict the evolution of the Moon and has important implications for the geologic study of other terrestrial planets.展开更多
The evolution of the Moon is driven by both endogenic(e.g.,magmatism)and exogenic processes(e.g.,impact).The lunar surface can be divided into 3 first-order tectonic units based on differences in geochemistry,crustal ...The evolution of the Moon is driven by both endogenic(e.g.,magmatism)and exogenic processes(e.g.,impact).The lunar surface can be divided into 3 first-order tectonic units based on differences in geochemistry,crustal thickness,topography,and distribution of structures.However,the interpreted boundaries demarcated by different features varied widely.As research progresses,the understanding of the lunar structure is continuously improving,and new types of structures are constantly being discovered.The previous structural classification system needs to be updated.According to the major geological events and dynamic evolution,the evolutionary history of the Moon can be divided into 3 stages and 1 pivotal event.The first stage(4.52 to 4.3 Ga)is the evolution of the magmatic ocean,and it was dominated by endogenic processes.The formation of South Pole-Aitken(SPA)basin(~4.3 Ga)is the pivotal event of crustal evolution and indicates that the lunar crust had cooled and consolidated to sufficient rigidity to preserve structures.Both endogenic and exogenic processes were active in the second stage(4.3 to 3.0 Ga),which results in numerous impact basins,mare basalt flooding,and different types of associated structures.The last stage(3.0 Ga to the present)is late neotectonic activity,which has weak modification of the tectonic framework.Response of tectonic framework and structure to lunar major geological events had been organized and discussed in this paper,and key scientific issues are summarized.This study can provide reference and support for implementation of subsequent lunar exploration projects.展开更多
Lunar shallow subsurface structure is important in revealing the formation and evolution of the Moon.Therefore,a review of key issues in the lunar shallow subsurface structure will help deepen our understanding of the...Lunar shallow subsurface structure is important in revealing the formation and evolution of the Moon.Therefore,a review of key issues in the lunar shallow subsurface structure will help deepen our understanding of the Moon.From a global perspective,lunar shallow subsurface structure is formed by endogenic and exogenic geological processes such as volcanic activities,tectonic activities,meteorite impacts,and space weathering.Its morphological characteristics and stratigraphic structure record the evolution of these geological processes.Recent lunar exploration missions have returned new samples and high-resolution data that have greatly enriched our knowledge.On the basis of reviewing the research progress of radar detection,crater-based excavation analysis,material inversion,and heat flow measurement,we also discuss the processes that contribute to the formation of the lunar shallow surface structure,such as volcanoes,impacts,tectonics,and space weathering.The main hot issues were sorted out and focused on 3 areas:transformation of lunar shallow subsurface structure by geological processes,environment and material composition of the lunar shallow surface structure,and physical properties of lunar shallow surface structure.Overall,existing research on the lunar subsurface has made significant progress,but it has also brought more new unsolved mysteries.It is necessary to introduce new applied payloads such as synthetic aperture radar(SAR),orbiter subsurface investigation radar(OSIR),or time-domain electromagnetic sounding(TDEM)to provide higher-resolution subsurface data,and develop better interpretation methodologies,to further deepen the understanding of the lunar shallow subsurface structure and indeed reveal the mechanism of lunar geological evolution.展开更多
基金Supported by Natural Science Foundation of Beijing "Effect of porcine skin-derived dendritic cells on PCV infection" (6062006)Beijing Organization Department Project"Influence of PCV infection on bone marrow cell differentiation" (20061D0502100282)~~
文摘[Objective] This study aimed to investigate the changes of the transcriptional levels of molecules associated with endogenous antigen processing and presenta- tion in porcine skin-derived dendritic cells infected with PCV2 in vivo. [Method] Healthy 40-day-old Landrace piglets were infected with porcine circovirus type 2 （PCV2） and euthanized on the 34, 7rd, 14th, 21st and 35th d post inoculation （DPI）. The porcine skin-derived dendritic cells （DCs） were collected to analyze the transcrip- tional levels of molecules （LMP7, UBP, MHC-I, calreticulin） associated with endogenous antigen processing and presentation by using real-time fluorescent quantitative PCR （real-time FQ-PCR）. [Result] The results showed that the level of LMP7 mR- NAs was reduced significantly on the 3DPI （P〈0.05）; the level of UBP mRNAs was consistently up-regulated, which increased significantly on the 21DPI and 35DPI （P〈 0.05）; the level of MHC-I mRNAs was significantly down-regulated on the 7DPI （P〈 0.05）; the level of calreticulin mRNAs was up-regulated slightly without significant dif- ference. [Conclusion] PCV2 can inhibit the endogenous antigen processing and presentation ability of porcine skin-derived DCs at early stages of infection.
基金supported by the China Geological Survey Projects(Nos.20160272,20211379)the Second Tibetan Plateau Scientific Expedition and Research Program(No.2019QZKK0904)。
文摘The dynamic effect is a very important issue widely debated by scholars when studying the genetic and disaster-causing mechanisms of earthquake-triggered landslides.First,the dynamic effect mechanism and phenomena of earthquake-triggered landslides were summarized in this paper.Then,the primary types of dynamic effects were further used to interpret the Mogangling landslide in Moxi Town of Luding County,China.A field investigation,remote sensing,numerical calculation and theoretical analysis were carried out to illustrate the failure mechanism of slope rock masses affected by earthquakes.The interaction between seismic waves and slope rock masses and the induced dynamic effect of slope rock masses were primarily accounted for in the analysis.The slope topography,rock mass weathering and unloading characteristics,river erosion,regional seismogenic structure,and rock mass structure characteristics were also discussed.The results showed that the formation of the Mogangling landslide was mainly related to the high amplification effect of seismic acceleration and back slope effects,interface dynamic stress effects,and double-sided slope effects of seismic waves caused by the catastrophic Ms 7.75 Moxi Earthquake in 1786.The principles for the site and route selection of large-scale infrastructure in the planning stage and the scientific prevention of seismic geological disasters were proposed on the basis of the dynamic effect of earthquake-induced landslides.
基金This work was supported partly by the National Key Research and Development Program of China(Grant No.2022YFF0503100)the B-type Strategic Priority Program of the Chinese Academy of Sciences(Grant No.XDB41000000)+1 种基金the National Natural Science Foundation of China(Grant Nos.41902317,41941002,41773065)the National Science and Technology Infrastructure Work Projects(Grant No.2015FY210500).
文摘A geologic time scale is a chronological system that separates the geological strata of a planetary body into different units in temporal sequence and shows its progressive evolution.The time scale of the Moon was established a half-century ago during the telescopic-early Apollo exploration era,using data with limited spatial coverage and resolution.The past decades have seen a wide array of studies,which have significantly extended our understanding of global lunar geologic evolution.Based on a comprehensive review of lunar evolution with respect to the dynamical changes,we propose two major updates to the current lunar time scale paradigm to include the evolution of both endogenic and exogenic dynamic forces now known to have influenced early lunar history.Firstly,based on the temporal interplay of exogenic and endogenic processes in altering the Moon,we defined three Eon/Eonothem-level units to represent three dynamical evolutionary phases.Secondly,the pre-Nectarian System is redefined and divided as the magma ocean-era Magma-oceanian System and the following Aitkenian System beginning with the South Pole-Aitken basin.The ejecta of this basin,Das Formation,was deposited on the primordial lunar crust as the oldest stratum produced from exogenic processes.The updated lunar time scale,facilitated by the post-Apollo exploration and research advances,provides an integrated framework to depict the evolution of the Moon and has important implications for the geologic study of other terrestrial planets.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFF0503100)the National Natural Science Foundation of China(Grant No.42202264)+2 种基金the National Natural Science Foundation of China-Academic Divisions of Chinese Academy of Sciences Frontier Interdisciplinary Research Strategic Research Joint Funding Project(Grant No.L2224032,XK2022DXC004)the Key Research Program of the Chinese Academy of Sciences,(Grant No.KGFZD-145-2023-15)Guizhou Provincial Science and Technology Projects(Grant No.[QKHJC-ZK(2023)-478]).
文摘The evolution of the Moon is driven by both endogenic(e.g.,magmatism)and exogenic processes(e.g.,impact).The lunar surface can be divided into 3 first-order tectonic units based on differences in geochemistry,crustal thickness,topography,and distribution of structures.However,the interpreted boundaries demarcated by different features varied widely.As research progresses,the understanding of the lunar structure is continuously improving,and new types of structures are constantly being discovered.The previous structural classification system needs to be updated.According to the major geological events and dynamic evolution,the evolutionary history of the Moon can be divided into 3 stages and 1 pivotal event.The first stage(4.52 to 4.3 Ga)is the evolution of the magmatic ocean,and it was dominated by endogenic processes.The formation of South Pole-Aitken(SPA)basin(~4.3 Ga)is the pivotal event of crustal evolution and indicates that the lunar crust had cooled and consolidated to sufficient rigidity to preserve structures.Both endogenic and exogenic processes were active in the second stage(4.3 to 3.0 Ga),which results in numerous impact basins,mare basalt flooding,and different types of associated structures.The last stage(3.0 Ga to the present)is late neotectonic activity,which has weak modification of the tectonic framework.Response of tectonic framework and structure to lunar major geological events had been organized and discussed in this paper,and key scientific issues are summarized.This study can provide reference and support for implementation of subsequent lunar exploration projects.
基金supported by the National Key R&D Program of China(2019YFE0123300)the National Natural Science Foundation of China(41872207,41602215,and L2224032)the Project on Frontier and Interdisciplinary Research Assessment,Academic Divisions of the Chinese Academy of Sciences(XK2022DXC004).
文摘Lunar shallow subsurface structure is important in revealing the formation and evolution of the Moon.Therefore,a review of key issues in the lunar shallow subsurface structure will help deepen our understanding of the Moon.From a global perspective,lunar shallow subsurface structure is formed by endogenic and exogenic geological processes such as volcanic activities,tectonic activities,meteorite impacts,and space weathering.Its morphological characteristics and stratigraphic structure record the evolution of these geological processes.Recent lunar exploration missions have returned new samples and high-resolution data that have greatly enriched our knowledge.On the basis of reviewing the research progress of radar detection,crater-based excavation analysis,material inversion,and heat flow measurement,we also discuss the processes that contribute to the formation of the lunar shallow surface structure,such as volcanoes,impacts,tectonics,and space weathering.The main hot issues were sorted out and focused on 3 areas:transformation of lunar shallow subsurface structure by geological processes,environment and material composition of the lunar shallow surface structure,and physical properties of lunar shallow surface structure.Overall,existing research on the lunar subsurface has made significant progress,but it has also brought more new unsolved mysteries.It is necessary to introduce new applied payloads such as synthetic aperture radar(SAR),orbiter subsurface investigation radar(OSIR),or time-domain electromagnetic sounding(TDEM)to provide higher-resolution subsurface data,and develop better interpretation methodologies,to further deepen the understanding of the lunar shallow subsurface structure and indeed reveal the mechanism of lunar geological evolution.
