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The late Mesozoic tectonic evolution of the eastern North China craton was intimately related with the subduction of the paleo-Pacific plate. This study sheds light on Late Jurassic-Early Cretaceous basin-mountain coupling during paleo-Pacific subduction based on low-temperature thermochronology and geochemical analyses from the easternmost Yanshan fold belt, located at the northern edge of the craton. We performed apatite U-Pb and fission-track double dating and trace element analyses of basement and sedimentary rock samples, integrated with zircon and apatite (U-Th)/He analyses on bedrock samples. Our results revealed that the easternmost Yanshan fold belt experienced two stages of rapid cooling and exhumation in the Middle Jurassic-earliest Cretaceous (ca. 170-140 Ma) and in the Early Cretaceous (ca. 140-90 Ma). The Middle Jurassic-earliest Cretaceous exhumation (ca. 170-140 Ma) is mainly recorded by bedrock along the margins of intermontane basins of the eastern Yanshan fold belt. This exhumation event is consistent with compressional Yanshan movement during the Middle Jurassic-earliest Cretaceous coeval with paleo-Pacific flat-slab subduction. Subsequent Early Cretaceous rapid cooling is ascribed to the progressive evolution of the metamorphic core complexes and associated tectonic exhumation of major plutons of northeastern Asia, which were likely controlled by rollback of the paleo-Pacific slab. A middle Cretaceous (ca. 110-90 Ma) tectonic exhumation event is revealed by very low lag-time values in middle Cretaceous strata. Our findings illustrate the potential of a thermochronology approach that combines single-grain double dating and trace element analyses in synmagmatic orogenic systems, which may find application to other orogenic settings worldwide. [ABSTRACT FROM AUTHOR]

Aim: To investigate the relationship between Helicobacter pylori infection and inflammatory bowel disease (IBD) in an Asian population., Methods: The PubMed, EMBASE, and Cochrane Library databases were searched for observational studies published up until June 2014, without language restrictions. Additional references were obtained from reviewed articles., Results: Ten studies involving 1299 IBD patients and 1817 controls were included in the meta-analysis (24.9% of IBD patients had H. pylori infection vs 48.3% of the controls). The pooled risk ratio for H. pylori infection in IBD patients compared with controls was 0.48 (95%CI: 0.43-0.54; P < 0.001). There was no significant heterogeneity in the included studies (I (2) = 21%). Egger's linear regression indicated that there was no significant publication bias (P = 0.203)., Conclusion: The H. pylori infection rate in Asian IBD patients is significantly lower than in non-IBD patients, indicating that infection protects against the development of IBD.