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77篇 您的检索式:作者名="Yanjun Dong"
    题名 作者 年代 出处 被引量
1New eolian red clay sequence on the western Chinese Loess Plateau linked to onset of Asian desertification about 25 Ma ago显示文摘The expansion of inland Asia deserts has considerably influenced the environmental, social and economic activities in Asia. Aridification of inland Asia, especially timing of the initiation of Asian desertification, is a contentious topic in paleoclimatology. Late Cenozoic eolian loess-red clay sequences on the Chinese Loess Plateau, which possess abundant paleoclimatic and paleo-environmental information, can be regarded as an indicator of inland Asia desertification. Here we present a detailed magnetostratigraphic investigation of a new red clay sequence about 654 m in Zhuanglang located at the western Chinese Loess Plateau. Sedimentological, geochemical, mineralogical, and quartz morphological lines of evidence show that the red clay is of eolian origin. Magnetostratigraphic correlations indicate that this core sequence spans from 25.6 to 4.8 Ma, and typical eolian red clay appears as early as 25 Ma. This extends the lower limit of the red clay on the Chinese Loess Plateau from the previously thought early Miocene back into the late Oligocene. This new red clay record further implies that the inland Asia desertification was initiated at least by the late Oligocene. This sequence provides a unique high-resolution geological record for understanding the inland Asia desertification process since the late Oligocene.QIANG XiaoKe AN ZhiSheng SONG YouGui CHANG Hong SUN YouBin LIU WeiGuo AO Hong DONG JiBao FU ChaoFeng WU Feng LU FengYan CAI YanJun ZHOU WeiJian CAO JunJi XU XinWen AI Li 2011Science China Earth Sciences2011,54,1:73
2Carbonyl emissions from heavy-duty diesel vehicle exhaust in China and the contribution to ozone formation potential显示文摘Fifteen heavy-duty diesel vehicles were tested on chassis dynamometer by using typical heavy duty driving cycle and fuel economy cycle. The air from the exhaust was sampled by 2,4-dinitrophenyhydrazine cartridge and 23 carbonyl compounds were analyzed by high performance liquid chromatography. The average emission factor of carbonyls was 97.2 mg/km, higher than that of light-duty diesel vehicles and gasoline-powered vehicles. Formaldehyde, acetaldehyde, acetone and propionaldehyde were the species with the highest emission factors. Main influencing factors for carbonyl emissions were vehicle type, average speed and regulated emission standard, and the impact of vehicle loading was not evident in this study. National emission of carbonyls from diesel vehicles exhaust was calculated for China, 2011, based on both vehicle miles traveled and fuel consumption. Carbonyl emission of diesel vehicle was estimated to be 45.8 Gg, and was comparable to gasolinepowered vehicles(58.4 Gg). The emissions of formaldehyde, acetaldehyde and acetone were 12.6, 6.9, 3.8 Gg, respectively. The ozone formation potential of carbonyls from diesel vehicles exhaust was 537 mg O3 /km, higher than 497 mg O3 /km of none-methane hydrocarbons emitted from diesel vehicles.Dong Dong Min Shao Yue Li Sihua Lu Yanjun Wang Zhe Ji Dagang Tang 2014Journal of Environmental Sciences2014,26,1:20
3The rice OsV4 encoding a novel pentatricopeptide repeat protein is required for chloroplast development during the early leaf stage under cold stress显示文摘Pentatricopeptide repeat(PPR)proteins,characterized by tandem arrays of a 35 amino acid motif,have been suggested to play central and broad roles in modulating the expression of organelle genes in plants.However,the molecular mechanisms of most rice PPR genes remains unclear.In this paper,we isolated and characterized a temperature-conditional virescent mutant,OsV4,in rice(Oryza sativa cultivar Jiahua1(WT,japonica rice variety)).The mutant displays albino phenotype and abnormal chloroplasts at the three leaf stage,which gradually turns green after the four leaf stage at a low temperature(20°C).But the mutant always develops green leaves and well-developed chloroplasts at a high temperature(32°C).Genetic and molecular analyses uncovered that OsV4 encodes a novel chloroplast-targeted PPR protein including four PPR motifs.Further investigations show that the mutant phenotype is associated with changes in chlorophyll content and chloroplast development.The OsV4transcripts only accumulate to high levels in young leaves,indicating that its expression is tissue-specific.In addition,transcript levels of some ribosomal components and plastid-encoded polymerase-dependent genes are dramatically reduced in the albino mutants grown at 20°C.These findings suggest that OsV4 plays an important role during early chloroplast development under cold stress in rice.Xiaodi Gong Qianqian Su Dongzhi Lin Quan Jiang Jianlong Xu Jianhui Zhang Sheng Teng Yanjun Dong 2014Journal of Integrative Plant Biology2014,56,4:19
4Study of Co-Simulation Methods Applied in Power Systems (Part I): VPNET显示文摘随着智能化电力电子装置在现代电力系统中的应用,信息交换成为电力系统完成复杂保护及控制功能的重要因素,因此通信系统的影响也应该在设计电力系统的过程中给予充分的考虑。但是,传统的电力系统仿真软件都没有系统仿真通信影响的能力;同时,搭建一种新的仿真软件需较多的时间和投入。联合仿真因此成为解决此类问题的另外一种选择,它能够利用各单个仿真软件已经存在的仿真模型,同时支持跨学科仿真软件之间的联合仿真。提出了一种新的联合仿真的平台VPNET,它综合了电力系统虚拟测试平台(virtualtestbed,VTB)和通信仿真软件OPNET来研究通信在电力系统中的影响。首先回顾了电力系统联合仿真方法的国内外发展概况,然后介绍了仿真方案VPNET以及实现该方案所需的关键技术。接着列举了该方案的2个具体应用:一是仿真网络化控制中延迟的影响;二是仿真基于多智能体通信的船舶电力系统保护。仿真结果符合理论分析,验证了该平台的有效性。LI Weilin ZHANG Xiaobin DONG Yanjun 2012中国电机工程学报2012,32,13:9
5Application of Avaatech X-ray fluorescence core-scanning in Sr/Ca analysis of speleothems显示文摘Application of X-ray fluorescence core-scanning(XRF-CS) on both marine and lake sediments has achieved remarkable results. However, its application has not been widely extended to the research on speleothems. In this study, we measure the Sr abundance and the Sr/Ca ratios of three stalagmites(two aragonite stalagmites, one calcite stalagmite) using the state-of-the-art fourth-generation Avaatech high-resolution XRF core scanner. Through comparisons among different scan paths and among different scan resolutions, as well as comparisons with inductively coupled plasma optical emission spectrometer(ICP-OES), Itrax XRF, and Artax XRF results, we confirm that the Avaatech XRF core scanner could precisely, quickly, and nondestructively analyze the high-resolution Sr abundance of speleothems. Furthermore, we combine the stalagmite δ^(18)O records to explore the paleoclimatic significance of the measured stalagmite Sr/Ca.Dong LI Liangcheng TAN Fei GUO Yanjun CAI Youbin SUN Gang XUE Xing CHENG Hong YAN Hai CHENG R.Lawrence EDWARDS Yongli GAO Jessica KELLEY 2019Science China Earth Sciences2019,62,6:7
6Empirical analysis of airport network and critical airports显示文摘Air transport network, or airport network, is a complex network involving numerous airports. Effective management of the air transport system requires an in-depth understanding of the roles of airports in the network. Whereas knowledge on air transport network properties has been improved greatly, methods to find critical airports in the network are still lacking. In this paper, we present methods to investigate network properties and to identify critical airports in the network. A novel network model is proposed with airports as nodes and the correlations between traffic flow of airports as edges. Spectral clustering algorithm is developed to classify airports. Spatial distribution characteristics and intraclass correlation of different categories of airports are carefully analyzed. The analyses based on the fluctuation trend of distance-correlation and power spectrum of time series are performed to examine the self-organized criticality of the network. The results indicate that there is one category of airports which dominates the self-organized critical state of the network. Six airports in this category are found to be the most important ones in the Chinese air transport network. The flights delay occurred in these six airports can propagate to the other airports, having huge impact on the operation characteristics of the entire network. The methods proposed here taking traffic dynamics into account are capable of identifying critical airports in the whole air transport network.Cong Wei Hu Minghua Dong Bin Wang Yanjun Feng Cheng 2016Chinese Journal of Aeronautics2016,29,2:7
7Characterization and mapping of a novel mutant sms1 (senescence and male sterility 1) in rice显示文摘Plant senescence plays diverse important roles in development and environmental responses.However,the molecular basis of plant senescence is remained largely unknown.A rice spontaneous mutant with the character of early senescence and male sterility (sms) was found in the breeding line NT10-748.In order to identify the gene SMS1 and the underlying mechanism,we preliminarily analyzed physiological and biochemical phenotypes of the mutant.The mutant contained lower chlorophyll content compared with the wild type control and was severe male sterile with lower pollen viability.Genetic analysis showed that the mutant was controlled by a single recessive gene.By the map-based cloning approach,we fine-mapped SMS1 to a 67 kb region between the markers Z3-4 and Z1-1 on chromosome 8 using 1,074 F2 recessive plants derived from the cross between the mutant sms1 (japonica) × Zhenshan 97 (indica),where no known gene involved in senescence or male sterility has been identified.Therefore the SMS1 gene will be a novel gene that regulates the two developmental processes.The further cloning and functional analysis of the SMS1 gene is under way.Wenyi Yan Shenghai Ye Qingsheng Jin Longjun Zeng Yu Peng Dawei Yan Weibing Yang Donglei Yang Zuhua He Yanjun Dong Xiaoming Zhang 2010Journal of Genetics and Genomics2010,37,1:6
8Comparison of Two Air Pollution Episodes over Northeast China in Winter 2016/17 Using Ground-Based Lidar显示文摘This study analyzes and compares aerosol properties and meteorological conditions during two air pollution episodes in 19–22(E1) and 25–26(E2) December 2016 in Northeast China. The visibility, particulate matter(PM) mass concentration, and surface meteorological observations were examined, together with the planetary boundary layer(PBL) properties and vertical profiles of aerosol extinction coefficient and volume depolarization ratio that were measured by a ground-based lidar in Shenyang of Liaoning Province, China during December 2016–January 2017.Results suggest that the low PBL height led to poor pollution dilution in E1, while the high PBL accompanied by low visibility in E2 might have been due to cross-regional and vertical air transmission. The PM mass concentration decreased as the PBL height increased in E1 while these two variables were positively correlated in E2. The enhanced winds in E2 diffused the pollutants and contributed largely to the aerosol transport. Strong temperature inversion in E1 resulted in increased PM2.5 and PM10 concentrations, and the winds in E2 favoured the southwesterly transport of aerosols from the North China Plain into the region surrounding Shenyang. The large extinction coefficient was partially attributed to the local pollution under the low PBL with high ground-surface PM mass concentrations in E1,whereas the cross-regional transport of aerosols within a high PBL and the low PM mass concentration near the ground in E2 were associated with severe aerosol extinction at high altitudes. These results may facilitate better understanding of the vertical distribution of aerosol properties during winter pollution events in Northeast China.Yanjun MA Hujia ZHAO Yunsheng DONG Huizheng CHE Xiaoxiao LI Ye HONG Xiaolan LI Hongbin YANG Yuche LIU Yangfeng WANG Ningwei LIU Cuiyan SUN 2018Journal of Meteorological Research2018,32,2:5
9A mechanically tuned Kerr comb in a dispersion-engineered silica microbubble resonator显示文摘This paper discusses the developement and investigation of a silica microbubble resonator(MBR) that is optimized to cancel mode dispersion with material dispersion, at a wavelength of approximately 1550 nm and maintain a quality factor of an optical mode as large as 5.4 × 10~7. Benefitting from the near-zero dispersion and high quality factor, a primary optical comb is generated in the MBR using cascaded four-wave mixing processes, which span over 300 nm with several tens of teeth. Furthermore, the frequency comb could be gradually tuned by mechanically stretching the MBR. This tunable Kerr comb has multiple potential applications in precision measurements and sensing applications, such as molecular spectroscopy and ranging.FangJie Shu PeiJi Zhang YanJun Qian ZhengYu Wang Shuai Wan Chang Ling Zou GuangCan Guo ChunHua Dong 2020Science China(Physics,Mechanics & Astronomy)2020,63,5:5
10Atomistic Surface Passivation of CH_(3)NH_(3)PbI_(3) Perovskite Single Crystals for Highly Sensitive Coplanar-Structure X-Ray Detectors显示文摘Organic-inorganic halide perovskites(OIHPs)are recognized as the promising next-generation X-ray detection materials.However,the device performance is largely limited by the ion migration issue of OIHPs.Here,we reported a simple atomistic surface passivation strategy with methylammonium iodide(MAI)to remarkably increase the ion migration activation energy of CH_(3)NH_(3)PbI_(3)single crystals.The amount of MAI deposited on the crystal surface is finely regulated by a self-assemble process to effectively suppress the metallic lead defects,while not introducing extra mobile ions,which results in significantly improved dark current stability of the coplanar-structure devices under a large electric field of 100Vmm^(-1).The X-ray detectors hence exhibit a record-high sensitivity above 700,000μC Gy^(-1)_(air) cm^(-2)under continuum X-ray irradiation with energy up to 50 keV,which enables an ultralow X-ray detection limit down to 1.5 nGy_(air)s^(-1).Our findings will allow for the dramatically reduced X-ray exposure of human bodies in medical imaging applications.Yilong Song Liqi Li Weihui Bi Mingwei Hao Yifei Kang Anran Wang Zisheng Wang Hanming Li Xiaohui Li Yanjun Fang Deren Yang Qingfeng Dong 2020Research2020,,1:5
11P-twisted affine Lie algebra and its realizations by twisted vertex operators显示文摘In this paper, we define a P-twisted affine Lie algebra, and construct its realizations by twisted vertex operators.LU Keping, CHU Yanjun, ZHENG Zhujun & DONG Wenfeng Institute of Mathematics, Henan University, Kaifeng 475001, China USTC Shanghai Institute for Advanced Studies, University of Science and Technology of China, Shanghai 201315, China 2005Science China Mathematics2005,48,z1:5
12Early Paleozoic Granulite-Facies Metamorphism and Magmatism in the Northern Wulan Terrane of the Quanji Massif:Implications for the Evolution of the Proto-Tethys Ocean in Northwestern China显示文摘The nature and evolution of the Proto-Tethys Ocean originated from the breakup of the supercontinent Rodinia remain controversial. Early Paleozoic magmatism and metamorphism can provide important constraints on the closure of the Proto-Tethys Ocean. This paper reports on a set of geological, petrographical, geochronological, mineralogical and geochemical data for Early Paleozoic granite, gabbro, granulite and granitic leucosome in the northern Wulan terrane of the Quanji Massif. Zircon LA-ICP-MS U-Pb dating reveals two episodes of magmatism, with the emplacement of a granitic pluton at 476.7±2.8 Ma and a gabbroic dike at 423±2 Ma. Whole-rock geochemistry suggests an arc affinity for the magma of the granitic pluton but a post-collisional extension setting for the gabbroic dike. Zircon LA-ICP-MS U-Pb dating also shows that the peak granulite-facies metamorphism and anatexis occurred at ~475 Ma, coeval with the formation of the granitic pluton in the Quanji Massif as well as the early lawsonite-bearing eclogites in the North Qaidam high-pressure and ultrahigh-pressure(HP-UHP) metamorphic belt to the south. The granulite-facies metamorphism with peak P-T conditions at 718–729 ℃ and 0.46–0.53 GPa is characterized by an anticlockwise P-T path. Our data provide compelling evidence for Early Paleozoic paired metamorphic belts with HP-UHP metamorphism in the North Qaidam to the south and low P/T metamorphism in the Quanji Massif as a continental arc to the north, hence suggesting a northward subduction polarity for the Proto-Tethys oceanic plate. The intrusion of the post-collisional gabbroic dike supports for the closure of the Proto-Tethys Ocean in northwestern China before 423 Ma.Qinyan wang Yanjun Dong Yuanming Pan Fanxi Liao Xiaowei Guo 2018Journal of Earth Science2018,29,5:4
13A fast arc fault detection method for AC solid state power controllers in MEA显示文摘Arc fault detection is desperately required in Solid State Power Controllers(SSPC) in addition to their fundamental functions because arcs will provoke growing harm and threat to aircraft safety. Experimental study has been done to obtain the faulted current data. In order to improve the detection speed and accuracy, two fast arc fault detection methods have been proposed in this paper with the analysis of only half cycle data. Both Fast Fourier Transform(FFT) and Wavelet Packets Decomposition(WPD) have been adopted to distinguish arc fault currents from normal operation currents. Analysis results show that Alternating Current(AC) arcs can be effectively and accurately detected with the proposed half cycle data based methods. Moreover,experimental verification results have also been provided.Weilin LI Kun HE Wenjie LIU Xiaobin ZHANG Yanjun DONG 2018Chinese Journal of Aeronautics2018,31,5:4
14Auxin-induced AUXIN RESPONSE FACTOR4 activates APETALA1 and FRUITFULL to promote flowering in woodland strawberry显示文摘Flowering time is known to be regulated by numerous pathways,such as the autonomous,gibberellin,aging,photoperiod-mediated,and vernalization pathways.These regulatory mechanisms involve both environmental triggers and endogenous hormonal cues.Additional flowering control mechanisms mediated by other phytohormones,such as auxin,are less well understood.We found that in cultivated strawberry(Fragaria×ananassa),the expression of auxin response factor4(FaARF4)was higher in the flowering stage than in the vegetative stage.Overexpression of FaARF4 in Arabidopsis thaliana and woodland strawberry(Fragaria vesca)resulted in transgenic plants flowering earlier than control plants.In addition,FveARF4-silenced strawberry plants showed delayed flowering compared to control plants,indicating that FaARF4 and FveARF4 function similarly in regulating flowering.Further studies showed that ARF4 can bind to the promoters of the floral meristem identity genes APETALA1(AP1)and FRUITFULL(FUL),inducing their expression and,consequently,flowering in woodland strawberry.Our studies reveal an auxin-mediated flowering pathway in strawberry involving the induction of ARF4 expression.Xiangxiang Dong Yanjun Li Yuhan Guan Shaoxi Wang He Luo Xiaoming Li He Li Zhihong Zhang 2021Horticulture Research2021,8,1:4
15Waterlogging stress in cotton:Damage, adaptability, alleviation strategies, and mechanisms显示文摘Over the last few decades,waterlogging stress has increasingly threatened global cotton production.Waterlogging results in reduced soil oxygen,impairing the growth and development of this valuable crop and often resulting in severe yield loss or crop failure.However,as cotton has an indeterminate growth habit,it is able to adapt to waterlogging stress by activating three mechanisms:the escape,quiescence,and self-regulating compensation mechanisms.The escape mechanism includes accelerated growth,formation of adventitious roots,and production of aerenchyma.The quiescence mechanism involves reduced biomass accumulation and energy dissipation via physiological,biochemical,and molecular events.The self-regulation compensation mechanism allows plants to exploit their indeterminate growth habit and compensatory growth ability by accelerating growth and development following relief from waterlogging stress.We review how the growth and development of cotton is impaired by waterlogging,focusing on the three strategies associated with tolerance and adaptation to the stress.We discuss agronomic measures and prospects for mitigating the adverse effects of waterlogging stress.Yanjun Zhang Guangya Liu Hezhong Dong Cundong Li 2021The Crop Journal2021,9,2:4
16Casein kinase Ⅱ interacts with prion protein in vitro and forms complex with native prion protein in vivo显示文摘最必要、关键的步在能递送的海绵状的 encephalopathy 的致病期间是到病理学的 isoform 的细胞的 prion 蛋白质的 conformational 变化。酷蛋白 kinase II (CK2 ) 是一无所不在地表示了并且 evolutionarily 保存了为生存能力是必要的多种的蛋白质 kinase。探索在 CK2 和 prion 蛋白质(PrP ) 之间的可能的分子的相互作用,人的 CK2α 和 CK2β 的全身的序列互补 DNA 作为模板从房间线 SH-SY5Y 用彻底的送信人 RNA 与反向的抄写聚合酶链反应被放大;然后,熔化蛋白质 histidine-CK2α 和谷胱甘肽 S-transferase-histidine-CK2β 在 Escherichia 关口 i 被表示。在 CK2 和 PrP 之间的相互作用与 co-immunoprecipitation 和下拉试金被评估。结果证明 recombinant PrP 与 CK2α ,然而并非与 CK2β 明确地跳了。在仓鼠大脑的本国的 CK2 和 PrP 与对方一起交往了,形成蛋白质建筑群。从正常大脑的 PrP (diglycosylated, monoglycosylated 和 unglycosylated PrP ) 的三种不同 glycosylated 形式与 CK2α 子单元交往了,尽管 unglycosylated PrP 似乎与 CK2α 子单元有一个更强壮的有约束力的能力。负责与 CK2α 交往的领域在 PrP 的 C 终端片断被定位(残余 91 231 ) 。这研究为在 PrP 和 CK2α 之间的分子的相互作用建议了可靠试验性的数据(两个在 recombinant 和本国的范畴) ,为进一步估计 PrP-CK2 相互作用的潜在的生物意义的科学线索,和在 prion 疾病的致病的 CK2 的可能的角色。Jianming Chen Chen Gao Qi Shi Guirong Wang Yanjun Lei Bing Shan Baoyun Zhang Chenfang Dong SongShi Xin Wang Chan Tian Jun Han Xiaoping Dong 2008Acta Biochimica et Biophysica Sinica2008,40,12:3
17PHYTOCHROME-INTERACTING FACTORS Interact with the ABA Receptors PYL8 and PYL9 to Orchestrate ABA Signaling in Darkness显示文摘PHYTOCHROME-INTERACTING FACTORS(PIFs)are a group of basic helix-loop-helix transcription factors that can physically interact with photoreceptors,including phytochromes and cryptochromes.It was previously demonstrated that PIFs accumulated in darkness and repressed seedling photomorphogenesis,and that PIFs linked different photosensory and hormonal pathways to control plant growth and development.In this study,we show that PIFs positively regulate the ABA signaling pathway during the seedling stage specifically in darkness.We found that PIFs positively regulate ABI5 transcript and protein levels in darkness in response to exogenous ABA treatment by binding directly to the G-box motifs in the ABI5 promoter.Consistently,PIFs and the G-box motifs in the ABI5 promoter determine ABI5 expression in darkness,and overexpression of ABI5 could rescue the ABA-insensitive phenotypes of pifq mutants in the dark.Moreover,we discovered that PIFs can physically interact with the ABA receptors PYL8 and PYL9,and that this interaction is not regulated by ABA.Further analyses showed that PYL8 and PYL9 promote PIF4 protein accumulation in the dark and enhance PIF4 binding to the ABI5 promoter,but negatively regulate PIF4-mediated ABI5 activation.Taken together,our data demonstrate that PIFs interact with ABA receptors to orchestrate ABA signaling in darkness by controlling ABI5 expression,providing new insights into the pivotal roles of PIFs as signal integrators in regulating plant growth and development.Lijuan Qi Shan Liu Cong Li Jingying Fu Yanjun Jing Jinkui Cheng Hong Li Dun Zhang Xiaoji Wang Xiaojing Dong Run Han Bosheng Li Yu Zhang Zhen Li William Terzaghi Chun-Peng Song Rongcheng Lin Zhizhong Gong Jigang Li 2020Molecular Plant2020,13,3:3
18Towards a better recording of microtubule cytoskeletal spatial organization and dynamics in plant cells显示文摘Numerous fluorescent marker lines are currently available to visualize microtubule(MT)architecture and dynamics in living plant cells, such as markers expressing p35S::GFP-MBD or p35S::GFP-TUB6.However, these MT marker lines display obvious defects that affect plant growth or produce unstable fluorescent signals. Here, a series of new marker lines were developed, including the pTUB6::VisGreen-TUB6-expressing line in which TUB6 is under the control of its endogenous regulatory elements and e GFP is replaced with VisGreen, a brighter fluorescent protein. Moreover, two different markers were combined into one expression vector and developed two dual-marker lines.These marker lines produce bright, stable fluorescent signals in various tissues, and greatly shorten the screening process for generating dual-marker lines.These new marker lines provide a novel resource for MT research.Weiwei Liu Chaofeng Wang Guangda Wang Yinping Ma Juan Tian Yanjun Yu Li Dong Zhaosheng Kong 2019Journal of Integrative Plant Biology2019,61,4:3
19PrP mutants with different numbers of octarepeat sequences are more susceptible to the oxidative stress显示文摘One of the physiological functions of cellular prion protein(PrP C )is believed to work as a cellular resistance to oxidative stress,in which the octarepeats region within PrP plays an important role.However,the detailed mechanism is less clear.In this study,the expressing plasmids of wild-type PrP (PrP-PG5)and various PrP mutants containing 0(PrP-PG0),9(PrP-PG9)and 12(PrP-PG12)octarepeats were generated and PrP proteins were expressed both in E.coli and in mammalian cells.Protein aggregation and formation of carbonyl groups were clearly seen in the recombinant PrPs expressed from E.coli after treatment of H2O2.MTT and trypan blue staining assays revealed that the cells expressing the mutated PrPs within octarepeats are less viable than the cells expressing wild-type PrP.Statistically significant high levels of intracellular free radicals and low levels of glutathione peroxidase were observed in the cells transfected with plasmids containing deleted or inserted octarepeats.Remarkably more productions of carbonyl groups were detected in the cells expressing PrPs with deleted and inserted octarepeats after exposing to H2O2.Furthermore,cells expressing wild-type PrP showed stronger resistant activity to the challenge of H2O2 at certain extent than the mutated PrPs and mock. These data provided the evidences that the octarepeats number within PrP is critical for maintaining its activity of antioxidation.Loss of its protective function against oxidative stress may be one of the possible pathways for the mutated PrPs to involve in the pathogenesis of familial Creutzfeldt-Jacob diseases.AN Run1 ,2,DONG ChenFang 2,LEI YanJun 1,2,HAN Lu 2,LI Ping 2,CHEN JianMing 2,WANG GuiRong 2, SHI Qi 2 ,GAO Chen 2 ,JIANG HuiYing 2 ,ZHOU Wei 2 ,HAN Jun 2 ,CHU YongLie 1 ,DONG XiaoPing 2 1School of Medicine,Xi’an JiaoTong University,Xi’an 710061,China 2State Key Laboratory for Infectious Disease Prevention and Control,National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention,YingXin Rd 100,Beijing 100052,China 2008Science China(Life Sciences)2008,51,7:3
20Late Mesozoic rifting and its deep dynamic mechanisms in the central Sulu orogenic belt: Records from Lingshan Island显示文摘The Lingshan Island scientific drill confirms that two episodes(Laiyang period and Qingshan period) of rifting developed in the central Sulu orogenic belt(SOB) in Late Mesozoic. With a set of methods including fieldwork, drilling, core logging, zircon U-Pb dating and whole rock geochemistry applied, the age, the depositional sequence and the deep dynamic mechanisms of rift evolution were unraveled. The stratigraphic sequence of the Laiyang-Qingshan Groups on Lingshan Island was composed of two different rifting sequences:(1) Laiyang Group(147–125 Ma), which consists of deep-water gravity flow deposits with interlayers of intermediate volcanic rocks;and(2) Lower Qingshan Group(125–119 Ma), which unconformably overlies the former sequence and contains subaerial volcanic deposits and terrestrial deposits. The tectonic environment changed during the evolution of these two episodes of rifting: the rift was in a NNW-SSE extensional environment in the Laiyang period and showed the typical passive rifting character that “lithospheric extension and rifting preceded volcanism”. The passive rifting period was ended by a short WNW-ESE compression at about 125 Ma. After that, the tectonic environment transferred to a strong NW-SE extensional environment and the rifting evolved into a volcanic arc basin in the Qingshan period. The igneous rocks are shoshonitic to high-K calc-alkaline trachyandesites to trachytes with a few intercalated lamprophyres and a rhyolite.The geochemical characteristics of the igneous rocks indicate that they are mantle-derived melts with a metasomatized mantle source and/or crustal contamination. In addition, an increased thinning of the lithosphere happened during the rifting episodes.The low-angle subduction of the Paleo-Pacific plate in the Jurassic weakened the thickened SOB lithospheric mantle. The rollback of the subducting plate started in late Jurassic to early Cretaceous, and the SOB lithospheric mantle was delaminated synchronously because of the gravity collapse. Thus, this caused passive rifting in the Laiyang period. Thereafter, the rollback and trench retreat of the high-angle subducting Paleo-Pacific plate would have achieved its climax, resulting in the strong regional extension. Passive rifting was ended by the crustal uplift caused by asthenospheric upwelling beneath the rift. The lower crust was heated by the upwelling asthenosphere and partially melted to form felsic melts, which were emplaced upwards and erupted explosively. The rift evolved into a volcanic arc basin in the Qingshan period and showed some characteristics of active rifting. Above all, a passive rifting in the Laiyang period and a volcanic arc basin in the Qingshan period developed successively in the Lingshan Island area(the central SOB). This records the transfer of the study area from the Paleo-Tethys tectonic domain to the circum-Pacific tectonic domain. The delamination of SOB lithospheric mantle and the upwelling of asthenospheric material were the deep dynamic mechanisms driving the development and evolution of two rift episodes. Additionally, the rift development was controlled remotely by the subduction of the Paleo-Pacific plate.Tengfei ZHOU Yaoqi ZHOU Nina SФAGER Paul Martin HOLM Zhenkai ZHANG Jun WANG Zhao LIANG Hongyu MU Yanjun CHENG Feifei LIU Miao WANG Yue ZHANG Hui ZHANG Yangjian GU Shihui DONG Hanjie ZHAO Manjie LI Yang CHEN Yanzi LIU 2022Science China Earth Sciences2022,65,9:3
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