Paleoenvironment reconstruction of the Middle Ordovician thick carbonate from western Ordos Basin, China

Reconstructing paleoenvironments has long been considered a vital component for understanding the development and evolution of carbonate reservoirs.The Middle Ordovician Period is considered the archetypical greenhouse interval,and also a critical period in biological evolution.The Middle Darriwilian isotope carbon excursion has been observed in many areas of the world and may be related to the biological explosions caused by decreases in the temperature.The thick carbonate rocks in the fifth member of the Middle Ordovician Majiagou Formation in the Dingbei area of the Ordos Basin were chosen as an example,based on the concentration of major,trace and rare earth elements as well as C,O and Sr isotopic analyses,the paleoenvironment was reconstructed.And its impact on natural gas exploration was analyzed.The results show that the seawater paleotemperature was 29℃,suboxicanoxic paleoredox conditions were observed,and the seawater paleosalinity was high.A large number of plankton in the biological explosion caused a rapid increase in the total organic carbon in carbonate rocks,which provided natural gas as supplemental source rocks.Affected by early meteoric water,the dissolution of gypsum laid the foundation for high-quality reservoirs,and the residual gypsum also further preserved natural gas.This study provides new data for the paleoenvironment and a theoretical basis for further natural gas exploration.

Fractionation characteristics of magnesium isotope in the ancient weathering crust

Weathering has always been a concerned around the world,as the first and most important step in the global cycle of elements,which leads to the fractionation of isotopes on the scale of geological age.The Middle Ordovician Majiagou Formation in Daniudi area of the Ordos Basin had experienced weathering for>130 Myr.Through thin section observation,major and trace element analysis,carbon,oxygen,and magnesium isotopes composition analysis,the dolomitization modes and weathering of ancient dolo-mite in Daniudi area were analyzed in detail.The results showed that the Sabkha and brine-reflux dolomitization modes had developed,and the Mg isotopes in different layers of the karst crust were fractionated by various factors.The vertical vadose zone was affected by weathering,the Mg isotope of dolomite(δ^(26)Mgdol)showed a downward decreasing trend;the horizontal underflow zone was controlled by diagenesis and formation fluid,δ^(26)Mgdol showed a vertical invariance and negative;the main reason for Mg isotope fractionation in the deep slow-flow zone was the brine-reflux dolomitization mode during early burial period,which showed a vertical downward increase.Finally,the Mg isotope characteristic data of the ancient weathering crust were provided and the process of Mg isotope frac-tionationinthekarstcrust was explained.

氯沙坦通过AT1R/VEGF信号通路对肝癌血管生成的影响

目的探讨氯沙坦是否通过下调血管紧张素Ⅱ1型受体(AT1R)/血管内皮生长因子(VEGF)信号通路,抑制肝癌细胞的血管生成。方法采用免疫荧光染色和Western blot检测AT1R在肝癌细胞系Hep G2、Hu H-7和PLC/PRF/5,以及正常肝细胞LO2中的表达。采用Western blot检测氯沙坦对肝癌细胞系Hep G2中AT1R表达的影响,酶联免疫吸附法(ELISA)检测氯沙坦对肝癌细胞系Hep G2中VEGF的影响。采用免疫组织化学法检测氯沙坦对大鼠肝癌组织中AT1R、VEGF和CD34表达的影响。结果AT1R在正常肝细胞LO2中低表达(P<0.05),在肝癌细胞系Hep G2、Hu H-7和PLC/PRF/5中高表达(P<0.05),在Hep G2细胞中表达最高(P<0.05)。在肝癌细胞系Hep G2中加入氯沙坦后,AT1R蛋白水平和VEGF浓度降低(P<0.05)。大鼠肝癌组织中AT1R、VEGF和CD34高表达,而加入氯沙坦后,AT1R、VEGF和CD34表达降低(P<0.05)。结论氯沙坦通过抑制AT1R/VEGF信号通路,可以阻碍肝癌血管的生成。

COVID-19 or treatment associated immunosuppression may trigger hepatitis B virus reactivation: A case report

BACKGROUND Since the initial recognition of coronavirus disease 2019(COVID-19)in Wuhan,this infectious disease has spread to most areas of the world.The pathogenesis of COVID-19 is yet unclear.Hepatitis B virus(HBV)reactivation occurring in COVID-19 patients has not yet been reported.CASE SUMMARY A 45-year-old hepatitis B man with long-term use of adefovir dipivoxil and entecavir for antiviral therapy had HBV reactivation after being treated with methylprednisolone for COVID-19 for 6 d.CONCLUSION COVID-19 or treatment associated immunosuppression may trigger HBV reactivation.

PROGRESS OF CHINESE REGIONAL GEOGRAPHY STUDIES IN RECENT TWENTY YEARS

Regional geography, embodying the regionality and integration, is the kernel of Geography. Since the 1980s, the Chinese geographers have extensively taken part in the social practical activities and made progress in physico geographical regionalization, economic regionalization, territorial (regional) development planning, construction of special economic zone, and integrated research in the major areas of China. Through these works, the theories of regional geography have been richened and the capacity participating in the social practice promoted as well. In China, many regional researches had been conducted respectively from the aspects of regional physico geography and regional economic geography, etc. According to the cases, this paper gives a review on the studies of regional geography during the latest two decades in China. It ought to be indicated that the natural and human components should be combined and the disciplines intersected and permeated, with the support of advanced technology. In order to serve the regional sustainable development, on the background of global change, this is an inevitable tendency for the development of the regional geography.

Cone-rod homeobox transcriptionally activates TCF7 to promote the proliferation of retinal pigment epithelial and retinoblastoma cells in vitro

AIM:To investigate the proliferation regulatory effect of cone-rod homeobox(CRX)in retinal pigment epithelium(RPE)and retinoblastoma(RB)cells to explore the potential application and side effect(oncogenic potential)of CRXbased gene therapy in RPE-based retinopathies.METHODS:Adult human retinal pigment epithelial(ARPE)-19 and human retinal pigment epithelial(RPE)-1 cells and Y79 RB cell were used in the study.Genetic manipulation was performed by lentivirus-based technology.The cell proliferation was determined by a CellTiter-Glo Reagent.The mRNA and protein levels were determined by quantitative real-time polymerase chain reaction(qPCR)and Western blot assay.The transcriptional activity of the promoter was determined by luciferase reporter gene assay.The bindings between CRX and transcription factor 7(TCF7)promoter as well as TCF7 and the promoters of TCF7 target genes were examined by chromatin immunoprecipitation(ChIP)assay.The transcription of the TCF7 was determined by a modified nuclear run-on assay.RESULTS:CRX overexpression and knockdown significantly increased(n=3,P<0.05 in all the cells)and decreased(n=3,P<0.01 in all the cells)the proliferation of RPE and RB cells.CRX overexpression and knockdown significantly increased and deceased the mRNA levels of Wnt signaling target genes[including MYC proto-oncogene(MYC),JUN,FOS like 1(FOSL1),CCND1,cyclin D2(CCND2),cyclin D3(CCND3),cellular communication network factor 4(CCN4),peroxisome proliferator activated receptor delta(PPARD),and matrix metallopeptidase 7(MMP7)]and the luciferase activity driven by the Wnt signaling transcription factor(TCF7).TCF7 overexpression and knockdown significantly increased and decreased the proliferation of RPE and RB cells and depletion of TCF7 significantly abolished the stimulatory effect of CRX on the proliferation of RPE and RB cells.CRX overexpression and knockdown significantly increased and decreased the mRNA level of TCF7 and the promoter of TCF7 was significantly immunoprecipitated by CRX antibody.CONCLUSION:CRX transcriptionally activates TCF7 to promote the proliferation of RPE and RB cells in vitro.CRX is a potential target for RPE-based regenerative medicine.The potential risk of this strategy,tumorigenic potential,should be considered.