排序方式： 共有3条查询结果，搜索用时 15 毫秒
1
1.
A kilometre-scale shear zone is recognized in the Cambro–Ordovician schist of the Bossòst dome, a Variscan metamorphic and structural dome in the Axial Zone of the central Pyrenees. Non-coaxial deformation is recorded by rotated garnet and staurolite porphyroblasts following regional metamorphism M1, while coaxial conditions prevailed during later contact metamorphic M2 growth of andalusite and cordierite. Mineral compositions and bulk rock analyses show that garnet–staurolite–andalusite–cordierite assemblages are significantly enriched in Mg and Mn over the garnet–staurolite assemblage, which lacks sufficient Mg for cordierite to form. The garnet–staurolite assemblage preserves conditions during M1, estimated by AFM diagrams and P–T pseudosections to be 5.5 kbar and 580 °C, respectively. Pseudosections also indicate that staurolite is not a stable phase in cordierite–andalusite assemblages of M2, suggesting polyphase metamorphism and decompression along a clockwise P–T path for the staurolite–cordierite–andalusite assemblages. This concurs with proposed extensional tectonics along the regional shear zone. To cite this article: J.E. Mezger et al., C. R. Geoscience 336 (2004). 相似文献
2.
为了探索大气颗粒物中石英粉尘诱导气道炎症反应的分子机制,采用XRD对石英粉尘进行了物相分析,并以支气管上皮细胞作为染毒对象,将石英粉尘作用于细胞24 h后,CCK-8检测细胞存活率,ELISA检测培养上清液中的白细胞介素-6(IL-6)和白细胞介素-8(IL-8)的浓度,Western Blot检测TLR4的表达,使用Toll样受体4特异性抑制剂TAK 242预处理后检测IL-6、IL-8、TLR4水平。实验结果显示,石英粉尘的主要物相是石英,并含部分方解石;随着石英粉尘染毒浓度的增加,细胞相对存活率下降;与对照组相比,100μg/mL组上清液中IL-6与IL-8浓度显著增加(P<0.01);50、75和100μg/mL组的高水平IL-6和IL-8可被TAK 242拮抗,使用TAK 242预处理后,100μg/mL组IL-6、IL-8浓度显著降低(P<0.01);TLR4的表达量随石英粉尘浓度增加而升高,且TAK 242的干预可以有效阻止TLR4通路的活化。研究结果表明,石英粉尘可以刺激支气管上皮细胞分泌高浓度的炎症因子,其机制可能是TLR4信号通路的活化。 相似文献
3.
《Chinese Astronomy and Astrophysics》2021,45(3):402-411
As an Earth co-orbital asteroid, (469219) Kamoòalewa is a near earth object (NEO) with high value of research, and one of the targets explored by the first Chinese asteroid exploration mission. Given its orbit characteristics, we build a refined dynamical model for this asteroid, in which the effects induced by nonspherical gravitational fields of the Sun, the Earth, and the Moon are combined. On the basis of the dynamical model of the asteroid (469219) Kamoòalewa, its orbit is determined with optical data from 2004 to 2018 available on the Minor Planet Center (MPC) database. The root mean square error of post-fit residuals is about 0.2 arc second (comparable with that of the Jet Propulsion Laboratory (JPL)/Horizons), and the post-fit residuals of optical observations in 2004 are decreased. At the end, we implement error analysis on the asteroid (469219) Kamoòalewa's orbit in detail, and also predict its orbit error at the time interval between 2020 and 2025. 相似文献
1