The study of the chlorite coatings always attracts scholars in China and other countries because the chlorite coatings play an important role in the preservation of residual primary pores in sandstone reservoirs.At pr...The study of the chlorite coatings always attracts scholars in China and other countries because the chlorite coatings play an important role in the preservation of residual primary pores in sandstone reservoirs.At present,the study of the origin and the controlling factors is relatively few.The occurrence,time of formation,genesis,controlling factors,and the mechanism of chlorite coatings inhibiting quartz overgrowths were studied in detail with thin section and SEM analysis.Samples were from the sandstone reservoirs of the T3x Group in the Baojie area,the transitional zone from the middle to the south of Sichuan Basin.The results indicate that the chlorite coatings on the walls of the pore spaces are oriented perpendicular to grain surfaces in the form of isopachous(even-thickness) grain-coating,while the chlorite coatings at the contacts between adjacent detrital grains are arranged with a preferred orientation tangential to the surface of detrital grains.The chlorite coatings were formed in the eogenetic stage.They were formed by recrystallization of Fe-rich clay films during the syndepositional period,and chlorite cements would be recrystallized after the coatings’ formation.The formation of chlorite coatings was mainly controlled by the depositional environment,provenance conditions,and diagenetic environment.The presence of chlorite coatings could result in the preservation of primary pores in deeply buried sandstone reservoirs by effectively inhibiting quartz overgrowths and the development of compaction and pressure solution.展开更多
目的分析女性孕前口腔菌群与胎儿过度生长的关联及可能机制。方法基于孕前队列,采取巢式病例对照研究设计,选取队列自2016年10月至2021年12月于上海市嘉定区妇幼保健院招募的人群中分娩巨大儿和/或大于胎龄儿(large for gestational age...目的分析女性孕前口腔菌群与胎儿过度生长的关联及可能机制。方法基于孕前队列,采取巢式病例对照研究设计,选取队列自2016年10月至2021年12月于上海市嘉定区妇幼保健院招募的人群中分娩巨大儿和/或大于胎龄儿(large for gestational age,LGA)的51例产妇作为病例组,按1∶4选取同期分娩正常出生体重儿、适于胎龄儿的204例产妇作为对照组。以总人群中分娩LGA的48例产妇作为LGA亚组,并从其余分娩非LGA的产妇中按1∶4随机抽取192例作为其相应对照组,展开LGA亚组分析。采用16S rRNA基因测序技术检测孕前唾液样本,比较组间口腔菌群特征、差异菌群与差异功能通路。采用非参数Wilcoxon秩和检验、两独立样本t检验,或χ^(2)检验(或Fisher精确概率法)进行统计学分析。对女性孕前膳食数据进行因子分析,以膳食模式因子得分的最大取值确定每个研究对象的主要膳食模式。对菌群计数数据,采用R和QIIME2软件计算α和β多样性指标,并通过PICRUSt2获得相应菌群功能计数数据。结果(1)一般资料:2组对象从孕前采样至妊娠及采样至分娩的时间间隔差异无统计学意义。病例组51例中,单纯巨大儿3例,LGA 48例(94.1%)。LGA亚组的相应对照为192例。病例组与对照组膳食模式差异无统计学意义。(2)α多样性分析:病例组物种丰富度指数低于对照组[(367.27±84.57)与(408.71±93.08),多因素分析P=0.009],而2组间Shannon指数和Simpson指数的差异则无统计学意义;LGA亚组的物种丰富度指数亦低于相应对照组[(371.04±83.92)与(408.04±94.21),多因素分析P=0.033],而Shannon指数和Simpson指数差异则无统计学意义。(3)β多样性分析:①病例组与对照组口腔菌群非加权UniFrac距离差异有统计学意义(R^(2)=0.006,F=1.479,P=0.048)。LGA亚组与相应对照组口腔菌群β多样性指标差异无统计学意义。(4)差异菌群分析:①病例组与对照组从门到属共有14个差异菌群。在属水平,消化链球菌科G1菌属在病例组富集,而劳特罗普氏菌属、小杆菌属、纤毛菌属和罗斯氏菌属则在对照组富集。②LGA亚组与相应对照组从门到属共有14个差异菌群;在属水平,罗斯氏菌属、纤毛菌属、单糖菌门G6菌属和月形单胞菌属在对照组富集(LDA值均>2,P值均<0.05)。(5)差异功能分析:病例组女性口腔菌群中烟酸降解[log_(2)差异倍数(fold change,FC)=3.510,q=0.005]、嘧啶核苷酸从头合成途径(log_(2)FC=0.078,q=0.005)及L-酪氨酸降解通路(log_(2)FC=0.710,q=0.034)等相关代谢功能通路富集。LGA亚组与相应对照组比较发现,LGA亚组口腔菌群中烟酸降解相关代谢功能通路富集(log_(2)FC=3.660,q=0.012)。结论过度生长胎儿的母亲孕前口腔菌群结构较正常生长胎儿的母亲存在差异,且正常生长胎儿的母亲孕前口腔菌群多样性更高。孕前口腔菌群中部分致病菌富集与共生菌减少与胎儿过度生长有关,这种关联可能通过烟酸降解等功能通路实现。展开更多
基金supported by the Natural Science Key Project of Education Board in Sichuan province,China (No.07ZA139)
文摘The study of the chlorite coatings always attracts scholars in China and other countries because the chlorite coatings play an important role in the preservation of residual primary pores in sandstone reservoirs.At present,the study of the origin and the controlling factors is relatively few.The occurrence,time of formation,genesis,controlling factors,and the mechanism of chlorite coatings inhibiting quartz overgrowths were studied in detail with thin section and SEM analysis.Samples were from the sandstone reservoirs of the T3x Group in the Baojie area,the transitional zone from the middle to the south of Sichuan Basin.The results indicate that the chlorite coatings on the walls of the pore spaces are oriented perpendicular to grain surfaces in the form of isopachous(even-thickness) grain-coating,while the chlorite coatings at the contacts between adjacent detrital grains are arranged with a preferred orientation tangential to the surface of detrital grains.The chlorite coatings were formed in the eogenetic stage.They were formed by recrystallization of Fe-rich clay films during the syndepositional period,and chlorite cements would be recrystallized after the coatings’ formation.The formation of chlorite coatings was mainly controlled by the depositional environment,provenance conditions,and diagenetic environment.The presence of chlorite coatings could result in the preservation of primary pores in deeply buried sandstone reservoirs by effectively inhibiting quartz overgrowths and the development of compaction and pressure solution.
