Early-middle Mesoproterozoic tectonic evolutionary history of the southwestern Yangtze Block,China:lithostratigraphic,geochronologic and elemental geochemical constraints

During the Early-Middle Proterozoic era,three major lithostratigraphic unit associations,namely Hekou-Dahongshan,Dongchuan,and Kunyang-Huili Groups,were established for the metamorphosed volcanicsedimentary rocks exposed in the southwestern Yangtze Block (SWYB).The integration of petrology, geochemistry and geochronology constrains tectonic framework and evolution of the SWYB,in which four sets of SHRIMP U-Pb zircon ages were obtained from the volcanic rocks interbedded within the Middle Proterozoic successions:1800-1600 Ma,1600-1300 Ma,1300-1100 Ma,and 1100-1000 Ma. Major and trace elemental analysis indicate that four key tectonic evolutionary stages,each coinciding with the above radiometric age set,of the SWYB during the Early-Middle Mesoproterozoic.The SWYB was characterized by an east-westerly trending rift in the Hekou,Dongshan,and Dongchuan areas,and separate basin-forming events during 1800-1600 Ma arid 1600-1300 Ma,respectively.In the SWYB,an intracontinental rift basin and a rift basin occurred in the Caiziyuan-Matang and Laowushan areas, respectively in 1300-1100 Ma ago.During 1100-1000 Ma,the SWYB was characterized by the closure of the Caiziyuan-Matang rift-ocean basin,collision between the Huili Blocks and Kunyang Blocks,and presence of volcanic ares in the Tianbaoshan and Fulingpen areas.Accordingly,the SWYB represents a new basin that records the relatively complete assembly process of the Rodina during the Early-Middle Mesoproterozoic era.

Immune Tolerance Therapy： A New Method for Treatment of Traumatic Brain Injury

Objective： Due to the special anatomical structure and pathophysiological mechanism of the central nervous system （CNS）, there is a big difference between the repair of brain injury and other systems of the body. More and more evidence shows that targetedly reducing the autoimmune response of brain tissue without affecting the immune function in other parts of the body will be the best optimized treatment for brain injury. Data Sources： This review was based on data in articles published in PubMed up to June 5,2017, with the following keywords： ＂immune tolerance＂, ＂traumatic brain injury＂, and ＂central nervous system＂. Study Selection： Original articles and critical reviews on immune tolerance and brain damage were selected for this review. References of the retrieved articles were also screened to search for potentially relevant papers. Results： The CNS is isolated from the immune system through the blood-brain barrier. After brain injury, brain antigens are released into the systemic circulation to induce damaging immune responses. Immune tolerance can effectively reduce the brain edema and neurological inflammatory response after brain injury, which is beneficial to the recovery of neurological function. The clinical application prospect and theoretical research value of the treatment of immune tolerance on traumatic brain inj ury （TBi） is worth attention. Conclusions： The establishment of immune tolerance mechanism has a high clinical value in the treatment of TBI. It opens up new opportunities for the treatment of brain damage.