Paleozoic tectonic evolution of the eastern Central Asian Orogenic Belt in NE China

The eastern Central Asian Orogenic Belt(CAOB)in NE China is a key area for investigating continental growth.However,the complexity of its Paleozoic geological history has meant that the tectonic development of this belt is not fully understood.NE China is composed of the Erguna and Jiamusi blocks in the northern and eastern parts and the Xing’an and Songliao-Xilinhot accretionary terranes in the central and southern parts.The Erguna and Jiamusi blocks have Precambrian basements with Siberia and Gondwana affinities,respectively.In contrast,the Xing’an and Songliao-Xilinhot accretionary terranes were formed via subduction and collision processes.These blocks and terranes were separated by the Xinlin-Xiguitu,Heilongjiang,Nenjiang,and Solonker oceans from north to south,and these oceans closed during the Cambrian(ca.500 Ma),Late Silurian(ca.420 Ma),early Late Carboniferous(ca.320 Ma),and Late Permian to Middle Triassic(260-240 Ma),respectively,forming the Xinlin-Xiguitu,Mudanjiang-Yilan,Hegenshan-Heihe,Solonker-Linxi,and Changchun-Yanji suture zones.Two oceanic tectonic cycles took place in the eastern Paleo-Asian Ocean(PAO),namely,the Early Paleozoic cycle involving the Xinlin-Xiguitu and Heilongjiang oceans and the late Paleozoic cycle involving the Nenjiang-Solonker oceans.The Paleozoic tectonic pattern of the eastern CAOB generally shows structural features that trend east-west.The timing of accretion and collision events of the eastern CAOB during the Paleozoic youngs progressively from north to south.The branch ocean basins of the eastern PAO closed from west to east in a scissor-like manner.A bi-directional subduction regime dominated during the narrowing and closure process of the eastern PAO,which led to“soft collision”of tectonic units on each side,forming huge accretionary orogenic belts in central Asia.

Magnetostratigraphy and paleoenvironmental record of late Cenozoic sediments in the Taiyuan Basin,North China

The Taiyuan Basin is of importance for intraplate tectonic deformation in North China and contains Cenozoic strata with a maximum thickness of 3800 m.A~853.5-m-deep borehole(ZK01)with an overall core recovery rate of 85.09%was drilled at Yuci(37°35'37?N,112°39'47?E)in the central Taiyuan Basin,to obtain high-resolution records of paleomagnetism,paleoclimatic and paleoenvironmental conditions,and depositional environment of the sediments.The obtained magnetic polarity sequence consists of 13 normal and 12 reverse zones,which correspond to C1n-C4An.2n of the geomagnetic polarity time scale.Magnetostratigraphic data show that the evolution of ZK01 core covers the interval from 8.1 Ma to the present,and the bottoms of Pliocene,Quaternary,and Middle Pleistocene were identified in Taiyuan Basin,with a sedimentary accumulation rate ranging from 62.5 m/Ma to 175.9 m/Ma.Geochemical data reveal that the source rocks in the study area underwent intense weathering and the sediments mainly formed in a semi-arid and oxygen-rich conditions.In addition,paleoclimatic changes occurred at~7 Ma,3.8 Ma,and 1.7 Ma,which can be closely related to the tectonic uplift of the Loess Plateau and Tibetan Plateau,as well as the variations in the Asian monsoon and associated regional and global climatic change.

Stability of trivalent human papillomavirus(types 16,18,58)recombinant vaccine(Escherichia coli)

To the Editor:There are 530,000 new cases of cervical cancer and 270,000 deaths annually in the world,85%occur in developing countries.Among them,about 150,000 new cases of cervical cancer are in China each year,accounting for one-third of the total patients worldwide.[1]Vaccines are the most economical and effective ways of preventing infectious diseases.To stop the transmission of human papillomavirus(HPV)fundamentally,the most effective measure is to vaccinate safe and effective HPV vaccines.[2,3]Numerous studies have shown that vaccines based on HPV L1 virus-like particles(VLPs)have good safety and protective efficacy.[4]Infection of HPV16,HPV18,and HPV58 viruses is the main cause of cervical cancer in Chinese women.By preventing the infection of HPV16,HPV18,and HPV58 viruses,85.0%to 93.7%of cervical cancers can be prevented.[5].