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1Variations of shear wave splitting in the 2008 Wenchuan earthquake region显示文摘Through the analysis of S-wave particle motion of local events in the shear wave window, the polariza-tion directions of the faster shear wave and the delay times between the faster and the slower shear waves were derived from seismic recordings at the stations near the fault zones. The shear wave split-ting results of seven stations in the area of Longmenshan fault zone reveal spatial variation of the po-larization directions of the fast shear wave. The directions at stations in the southeastern side of the Longmenshan fault zone (in the Sichuan Basin area) are in the NE direction, whereas the direction at station PWU (in the Plateau), which is in the northwestern side of the faults, is in the EW direction. Systematic changes of the time delays between two split shear waves were also observed. At station L5501 in the southern end of the aftershock zone, the delay times of the slower shear wave decrease systematically after the main shock. After the main shock, the delay times at station PWU were longer than those before the earthquake. Seismic shear wave splitting is caused mostly by stress-aligned microcracks in the rock below the stations. The results demonstrate changes of local stress field dur-ing the main-shock and the aftershocks. The stress in the southern part of Wenchuan seismogenic zone was released by the main-shock and the aftershocks. The crustal stresses were transferred to the northeastern part of the zone, resulting in stress increase at station PWU after the main-shock.DING ZhiFeng WU Yan WANG Hui ZHOU XiaoFeng LI GuiYin 2008Science China Earth Sciences2008,51,12:18
2Human monoclonal antibodies block the binding of SARS-CoV-2 spike protein to angiotensin converting enzyme 2 receptor显示文摘According to the World Health Organization(WHO)newly updated situation report on March 18th,2020,the coronavirus disease 2019(COVID-19)pandemic has confirmed 191,127 cases and claimed 7807 deaths worldwide.1 The etiological agent of COVID-19 has been identified as a novel coronavirus,the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),belonging to Sarbecovirus subgenus(genus Betacoronavirus,family Coronaviridae)and showing 79.6 and 96.2%sequence identity in nucleotide to SARS-CoV and a bat coronavirus(BatCoV RaTG13),respectively.2–4 Like SARS-CoV infection,a substantial fraction of COVID-19 patients exhibits severe respiratory symptoms and has to be hospitalized in intensive care unit.5–8 Although the mortality rate of COVID-19 is significantly lower than that of SARS-CoV infection,SARS-CoV-2 shows much higher human-to-human transmission rate,rapidly leading to a global pandemic declared by WHO on March 11th,2020.Xiangyu Chen Ren Li Zhiwei Pan Chunfang Qian Yang Yang Renrong You Jing Zhao Pinghuang Liu Leiqiong Gao Zhirong Li Qizhao Huang Lifan Xu Jianfang Tang Qin Tian Wei Yao Li Hu Xiaofeng Yan Xinyuan Zhou Yuzhang Wu Kai Deng Zheng Zhang Zhaohui Qian Yaokai Chen Lilin Ye 2020Cellular & Molecular Immunology2020,17,6:17
3Preparation of ChlL-2 and IBDV VP2 Fusion Protein by Baculovirus Expression System显示文摘This study aims to produce an effective subunit vaccine against infectious bursal disease virus (IBDV). The genes of chicken interleukin-2 (ChIL-2) and IBDV viral protein 2 (VP2) were amplified and fused by splice overlap extension-polymerase chain reaction (SOE-PCR). The fusion gene was digested by EcoR I/Kpn I and inserted into pBacPAK8 vector, resulting in recombinant transfer plasmid pBacPakVP2-IL2. The recombinant plasmid was transfected into Sf-9 cells accompanied with hybrid nuclear polyhedrosis virus (HyNPV) genome DNA and lipofectin. Plaque-purification indicated that we had got the recombinant Hy-VP2-IL2. Fusion protein VP2-IL2was expressed effectively both in insect cells and bombyx mori. The expression of fusion protein was confirmed by ELISA, SDS-PAGE and Western blotting assay, respectively. This efficient system allows us to meet the need for inexpensive vaccines required by the poultry industry.Yan Liu Yongwei Wei Xiaofeng Wu Lian Yu 2005Cellular & Molecular Immunology2005,2,3:12
4Tomographic imaging of P wave velocity structure beneath the region around Beijing显示文摘The three-dimension crustal and upper mantle structures in the region around Beijing were studied by seismic tomography. We used the P wave arrival times from local and teleseismic events. These events were recorded by 250 stations of the North China Seismic Array and 108 stations of the Beijing Telemetry Seismic Network. 118 869 P wave arrivals from 10 285 local events and 12 189 P wave arrivals from 107 teleseismic events were used in the inversion. We obtained the 3-D P wave velocity structure of the crust and upper mantle with the horizontal resolution of 0.3° in the studied region. The tomographic imaging shows the remarkably heterogeneous velocity variation. The velocity anomalies are in well agreement with the geological structure in the shallow crust. The different relationships between seismic activities and velocity anomalies may imply the different seismogenic structure and mechanism. Beneath the Moho under Taihangshan mountain and Yanshan mountain,we found the high velocity anomalies deep to 120 km and 200 km,respectively. The deep high velocity zone may be explained by the existence of the mountain root under Yanshan mountain. The high velocity anomalies in the upper mantle of North China basin may be the relics of the de-rooting from the former craton mantle lithosphere.Zhifeng Ding Xiaofeng Zhou Yan Wu Guiyin Li Hong Zhang 2009Earthquake Science2009,22,4:10
5Functional Characterization of the Promoter and Second Intron of CUM1 During Flower Development in Cucumber(Cucumis sativus L.)显示文摘The characterization of flower specific promoter is critical during flower development by cucumber transformation technology.AGAMOUS(AG)is an organ identity gene that is required for carpel and stamen development in Arabidopsis.The promoter and second intron of AG contain multiple regulatory elements that confer proper spatial and temporal expression.Cucumber is an important vegetable with unisexual flowers.Cucumber MADS-box 1(CUM1)is the AG homolog in cucumber,belonging to the eu AG lineage along with AG.In situ hybridization showed that CUM1 was specifically expressed in the stamens and carpels of cucumber.GUS staining indicated that the second intron of CUM1 confers stamen-specific expression,while the promoter of CUM1 drives both stamen-and carpel-specific expression during the early stages of flower development,but is restricted to carpel-and connectivum-specific expression during the late stages of flower development.Furthermore,a yeast one-hybrid assay demonstrated that two auxin response factors(Cs ARF13 and Cs ARF17)had bound directly to the second intron of CUM1.Our data suggest that different regulatory circuits operate in AG homologs in plant species with distinct sex types.GU Ran LIU Xiaofeng ZHAO Wensheng YAN Shuangshuang SUN Linhan WU Binning ZHANG Xiaolan 2018Horticultural Plant Journal2018,4,3:9
6Normal Structure and Function of Endothecium Chloroplasts Maintained by ZmMs33-Mediated Lipid Biosynthesis in Tapetal Cells Are Critical for Anther Development in Maize显示文摘Genic male sterility(GMS)is critical for heterosis utilization and hybrid seed production.Although GMS mutants and genes have been studied extensively in plants,it has remained unclear whether chloroplast-associated photosynthetic and metabolic activities are involved in the regulation of anther development.In this study,we characterized the function of ZmMs33/ZmGPAT6,which encodes a member of the glycerol-3-phosphate acyltransferase(GPAT)family that catalyzes the first step of the glycerolipid synthetic pathway.We found that normal structure and function of endothecium(En)chloroplasts maintained by ZmMs33-mediated lipid biosynthesis in tapetal cells are crucial for maize anther development.ZmMs33 is expressed mainly in the tapetum at early anther developmental stages and critical for cell proliferation and expansion at late stages.Chloroplasts in En cells of wild-type anthers function as starch storage sites before stage 10 but as photosynthetic factories since stage 10 to enable starch metabolism and carbohydrate supply.Loss of ZmMs33 function inhibits the biosynthesis of glycolipids and phospholipids,which are major components of En chloroplast membranes,and disrupts the development and function of En chloroplasts,resulting in the formation of abnormal En chloroplasts containing numerous starch granules.Further analyses reveal that starch synthesis during the day and starch degradation at night are greatly suppressed in the mutant anthers,leading to carbon starvation and low energy status,as evidenced by low trehalose-6-phosphate content and a reduced ATP/AMP ratio.The energy sensor and inducer of autophagy,SnRK1,was activated to induce early and excessive autophagy,premature PCD,and metabolic reprogramming in tapetal cells,finally arresting the elongation and development of mutant anthers.Taken together,our results not only show that ZmMs33 is required for normal structure and function of En chloroplasts but also reveal that starch metabolism and photosynthetic activities of En chloroplasts at different developmental stages are essential for normal anther development.These findings provide novel insights for understanding how lipid biosynthesis in the tapetum,the structure and function of En chloroplasts,and energy and substance metabolism are coordinated to maintain maize anther development.Taotao Zhu Ziwen Li Xueli An Yan Long Xiaofeng Xue Ke Xie Biao Ma Danfeng Zhang Yijian Guan Canfang Niu Zhenying Dong Quancan Hou Lina Zhao Suowei Wu Jinping Li Weiwei Jin Xiangyuan Wan 2020Molecular Plant2020,13,11:9
7Mg-Zn-Y-Nd coated with citric acid and dopamine by layer-by-layer self-assembly to improve surface biocompatibility显示文摘Magnesium alloy has been generally accepted as an important biodegradable material on cardiovascular stent development for a long time. However, its limited biocompatibility, especially delayed endothelialization process restricts its further application. In this contribution, we modified the Mg-Zn-Y-Nd alloy surface with citric acid and dopamine via a layer-by-layer self-assembly assay, aiming at improving the biocompatibility of the magnesium alloy. The citric acid/dopamine(CA/PDA) layer exhibited a remarkable suppression of platelet activation/aggregation and thrombosis under 15 dyn/cm2 blood flowing. Inhibition on vascular smooth muscle cells growth and macrophages attachment/activation were also observed on this layer. In particular, the CA/PDA layer presented a promoted property for the vascular endothelial cells growth and spreading compared with the bare magnesium alloy, suggesting the pro-endotelialized function. In conclusion, this research may support potential application on surface modification of magnesium alloy based cardiovascular stents for better biocompatibility.CHEN Li LI JingAn CHANG JiaWei JIN ShiBo WU Di YAN HaoHao WANG XiaoFeng GUAN ShaoKang 2018Science China(Technological Sciences)2018,61,8:7
8Statistical and frequency analysis of the pressure fluctuation in a fluidized bed of non-spherical particles显示文摘In this paper,the pressure fluctuation in a fluidized bed was measured and processed via standard deviation and power spectrum analysis to investigate the dynamic behavior of the transition from the bubbling to turbulent regime.Two types[Geldart B and D) of non-spherical particles,screened from real bed materials,and their mixture were used as the bed materials.The experiments were conducted in a semiindustrial testing apparatus.The experimental results indicated that the fluidization characteristics of the non-spherical Geldart D particles differed from that of the spherical particles at gas velocities beyond the transition velocity U_c.The standard deviation of the pressure fluctuation measured in the bed increased with the gas velocity,while that measured in the plenum remained constant.Compared to the coarse particles,the fine particles exerted a stronger influence on the dynamic behavior of the fluidized bed and promoted the fluidization regime transition from bubbling toward turbulent.The power spectrum of the pressure fluctuation was calculated using the auto-regressive(AR) model;the hydrodynamics of the fluidized bed were characterized by the major frequency of the power spectrum of the pressure fluctuation.By combining the standard deviation analysis,a new method was proposed to determine the transition velocity U_k via the analysis of the change in the major frequency.The first major frequency was observed to vary within the range of 1.5 to 3 Hz.Honghao He Xiaofeng Lu Wei Shuang Quanhai Wang Yinhu Kang Liyun Yan Xuanyu Ji Guangyu Luo Hai Liu 2014Particuology2014,12,5:6
9Midterm results of diagnostic treatment and repair strategy in older patients presenting with nonrestrictive ventricular septal defect and severe pulmonary artery hypertension显示文摘Liu Aijun Li Zhiqiang Li Xiaofeng Fan Xiangming Su Junwu Zhang Jing He Yan Liu Yinglong 2014Chinese Medical Journal2014,,5:6
10SLIPS-TENG: robust triboelectric nanogenerator with optical and charge transparency using a slippery interface显示文摘Energy harvesting devices that prosper in harsh environments are highly demanded in a wide range of applications ranging from wearable and biomedical devices to self-powered and intelligent systems.Particularly,over the past several years,the innovation of triboelectric nanogenerators(TENGs)that efficiently convert ambient kinetic energy of water droplets or wave power to electricity has received growing attention.One of the main bottlenecks for the practical implications of such devices originates from the fast degradation of the physiochemical properties of interfacial materials under harsh environments.To overcome these challenges,here we report the design of a novel slippery lubricant-impregnated porous surface(SLIPS)based TENG,referred to as SLIPS-TENG,which exhibits many distinctive advantages over conventional design including optical transparency,configurability,self-cleaning,flexibility,and power generation stability,in a wide range of working environments.Unexpectedly,the slippery and configurable lubricant layer not only serves as a unique substrate for liquid/droplet transport and optical transmission,but also for efficient charge transfer.Moreover,we show that there exists a critical thickness in the liquid layer,below which the triboelectric effect is almost identical to that without the presence of such a liquid film.Such an intriguing charge transparency behavior is reminiscent of the wetting transparency and van der Waals potential transparency of graphene previously reported,though the fundamental mechanism remains to be elucidated.We envision that the marriage of these two seemingly totally different arenas(SLIPS and TENG)provides a paradigm shift in the design of robust and versatile energy devices that can be used as a clean and longer-lifetime alternative in various working environments.Wanghuai Xu Xiaofeng Zhou Chonglei Hao Huanxi Zheng Yuan Liu Xiantong Yan Zhengbao Yang Michael Leung Xiao Cheng Zeng Ronald X. Xu Zuankai Wang 2019National Science Review2019,6,3:6
11Abiogenic hydrocarbons in commercial gases from the Songliao Basin,China显示文摘This paper discusses the kinetic fractionation, composition and distribution characteristics of carbon and hydrogen isotopes for various alkane gases formed in different environments, by different mecha- nisms and from different sources in nature. It is demonstrated that the biodegradation or thermode- gradation of complex high-molecule sedimentary organic material can form microbial gas or thermogenic gas. The δ 13C1 value ranges from -110‰ to -50‰ for microbial gases but from -50‰ to -35‰ (even heavier) for thermogenic gases. Controlled by the kinetic isotope fractionation, both microbial and thermogenic gases have δ 13C and δ D values characterized by normal distribution, i.e. δ 13C1< δ 13C2< δ 13C3< δ 13C4 and δ DCH4< δ DC2H6< δ DC3H8<δ DC4H10, and by a positive correlation between the δ 13C and δ D values. Simple carbonbearing molecules (CH4, CO and CO2) can form abiogenic alkane gases via polymerization in the abiological chemical process in nature, with δ 13C1 heavier than -30‰. Moreover, controlled by the kinetic isotope fractionation, abiogenic alkane gases are characterized by a reverse distribution of δ 13C values and a normal trend of δ D values, namely δ 13C1> δ 13C2> δ 13C3> δ 13C4 and δ DCH4<δ DC2H6< δ DC3H8< δ DC4H10. The δ 13C values and δ D values are negatively correlated. Natural gases from 26 commercial gas wells distributed in the Xujiaweizi and Yingshan-Miaotaizi faulted depressions in the Songliao Basin, China, show δ13C1 values ranging from -30.5‰ to -16.7‰ with a very narrow δ D range between -203‰―-196‰. These gases are characterized by a reverse distribution of δ 13C values but a normal distribution of δ D values, and a negative correlation between their δ 13C and δ D values, indicating an abiological origin. The present study has revealed that abiogenic hydrocarbons not only exist in nature but also can make significant contribution to commercial gas reserviors. It is estimated that the reserve volume of alkane gases with abiogenic characteristics in these 26 gas wells in the Songliao Basin is over 500×108 m3. The prospecting practice in the Songliao Basin has demonstrated that abiogenic alkane gases are of a promising resource, and it provides an example for the investigation of and search for abiogenic commercial natural gases worldwide.WANG XianBin GUO ZhanQian TUO JinCai GUO HongYan LI ZhenXi ZHUO ShengGuang JIANG HongLiang ZENG LongWei ZHANG MingJie WANG LianSheng LIU ChunXue YAN Hong LI LiWu ZHOU XiaoFeng WANG YongLi YANG Hui WANG Guang 2009Science China Earth Sciences2009,52,2:6
12Microstructural evolution of Au-Sn solder prepared by laminate rolling during annealing process显示文摘The microstructural evolution and interfacial reaction of the Au/Sn/Au/Sn/Au/Sn/Au couples were investigated during annealing at 453,523,and 543 K for up to 240 h.The Au/Sn combination formed a rapid diffusion system.Even in rolled Au-Sn solder,three phases,such as AuSn,AuSn2,and AuSn4,were formed.After initial annealing at 453 K,the diffusion layers of AuSn,AuSn2,and AuSn4,which were formed after rolling,expanded gradually and then fully transformed into ζ phase(containing Sn from 10% to 18.5%,mole fraction) and δ(AuSn) phase.As a whole,the microstructure of the couple was stable during annealing at 453 K.The solid-state interfacial reaction was much faster at 523 K than at 453 K.After annealing at 523 K for 6 h,the AuSn,AuSn2,and AuSn4 were fully transformed into the ζ phase and δ phase(AuSn) .In spite of the prolonged annealing time for up to 240 h,no significant change of the interfacial microstructure occurred,and the microstructure of the couple was stable during annealing at 523 K.When annealing at 543 K,however,the interfacial of Au/Sn was transformed into solid-liquid state,and the whole couple formed a eutectic structure rapidly,causing the solder to be brittle.The study results clearly demonstrate that the service temperature of the Au-Sn solder should be lower than 543 K.WEI Xiaofeng WANG Richu FENG Yan ZHU Xuewei PENG Chaoqun 2011Rare Metals2011,30,6:5
13Structure of the human activated spliceosome in three conformational states显示文摘在拼接的 pre-mRNA 的每个周期期间, pre 催化的 spliceosome (B 建筑群) 被变换成激活的 spliceosome (B 行为 建筑群) ,它有一个合法活跃地点但是不能继续到分叉的反应。这里,我们在场人的 B 处于三个不同 conformational 状态的行为 建筑群。他们地图允许将近所有的原子建模 U2 小原子 ribonucleoprotein (snRNP ) 的蛋白质部件,包括三 SF3a 建筑群和七 SF3b 建筑群。人的 B 行为 建筑群包含 52 蛋白质, U2, U5,和 U6 小原子 RNA (snRNA ) ,和 pre-mRNA。三不同符合构造被捕获了,代表人的 B 行为 建筑群。这些建筑群在开关环的取向不同 Prp8,拼接的因素 RNF113A 和 NY-CO-10,和十九建筑群(NTC ) 和 NTC 相关的建筑群的大多数部件。有 B 和 C 建筑群的这三建筑群和比较的分析在 B-to-B 行为 和 B 行为 -to-B* 转移,它最终为分叉的反应告知活跃地点。Xiaofeng Zhang, Chuangye Yan, Xiechao Zhan, Lijia Li, Jianlin Lei, Yigong Shi Jianlin Lei Yigong Shi 2018Cell Research2018,28,3:4
14The five major autoimmune diseases increase the risk of cancer:epidemiological data froma large-scale cohort study in China显示文摘Background:Cancer incidence and mortality have received critical attention during the long-term management of morbidities in patients with autoimmune diseases(AIDs).This study aimed to investigate and compare the risk of cancer associated with five major AIDs in a large-scale Chinese cohort.Methods:A total of 8,120 AID patients consecutively admitted to a national tertiary referral center in China were included and followed-up for 38,726.55 patient-years,including those with systemic lupus erythematosus(SLE),rheumatoid arthritis(RA),Sjoren’s syndrome(SS),systemic scleroderma(SSc),and idiopathic inflammatory myositis(IIM).Demographic data,cancer incidence,predilecting sites and cancer onset time were recorded and compared among the five AIDs.Results:Four hundred and thirty(5.3%)patients developed cancer.Their median agewas 57.5 years and AID durationwas 79.8 months.The estimated total standardized incidence ratio(SIR)of cancer in AIDs patients was 3.37,with the highest SIR observed in IIM(4.31),followed by RA(3.99),SSc(3.77),SS(2.88)and SLE(2.58).The increased SIR of cancers in AID patients showed a female predominance(female vs.male:3.59 vs.2.77)and younger patient involvement(age<50 vs.≥50 years:4.88 vs.3.04).Patientswith SLE had increased SIRs for developing hematologic malignancies and solid tumors located in the urinary bladder,corpus uteri and cervix uteri.Patients with SS had a significantly high SIR for developing non-Hodgkin’s lymphoma.Within 3 years of IIM diagnosis,74.6%of the patients developed cancer and they had a high risk of ovarian cancer.RA was associated with a wide distribution of scancers,including non-Hodgkin’s lymphoma,gynecologic,urinary tract,thyroid gland and lung cancers.SSc patients had increased SIRs for developing cervical uterine,lung,and breast cancers.Conclusion:Patients with five major AIDs in China had an increased risk of developing cancer,with a predominance in women and younger patients,although cancer incidence,predilection sites and cancer onset time may vary greatly in each AID entity.Ziyue Zhou Huazhen Liu Yiying Yang Jingya Zhou Lidan Zhao Hua Chen Yunyun Fei Wen Zhang Mengtao Li Yan Zhao Xiaofeng Zeng Fengchun Zhang Huaxia Yang Xuan Zhang 2022Cancer Communications2022,42,5:4
15Effects of Ti addition on the microstructure and mechanical properties of Mg-Zn-Zr-Ca alloys显示文摘The effects of Ti additions(0,0.4,0.6,0.8,1.0,1.2 wt.%)on the microstructure and mechanical properties of as-cast and aging Mg-0.4%Zn-1.0%Zr-1.5%Ca(wt.%)alloys were investigated.The results indicated that minor Ti can effectively refine grains,while excessive Ti addition resulted in the grain coarsening.When the content of Ti was 0.8 wt.%,the as-cast alloy exhibited the finest grain size of 39μm which contributed to the optimal mechanical properties with Brinell hardness of 57.9 HB,ultimate tensile strength of 145 MPa and elongation of 3.2%.After T6 heat treatment,the continuous net-like Mg_(2)Ca and Mg_(6)Zn_(3)Ca_(2)phases changed to uniform massive T phases(ternary Mg-Zn-Ca phases)and dispersive halo-like precipitates(Mg_(2)Ca and Mg_(6)Zn_(3)Ca_(2)phases).The ultimate tensile strengths of the alloy at room temperature(RT),175℃and 200℃were correspondingly improved to 182 MPa,169 MPa and 141 MPa,respectively.Jingai Chen Yan Sun Jinshan Zhang Weili Cheng Xiaofeng Niu Chunxiang Xu 2015Journal of Magnesium and Alloys2015,3,2:4
16Temporal variability of iron concentrations and fractions in wetland waters in Sanjiang Plain, Northeast China显示文摘Chemical forms, reactivities and transformation of iron fractions in marshy waters were investigated with cross-flow filtration technique to study the iron environmental behavior. Iron fractions were divided into four parts: acid-labile iron (pre-acidification of unfiltered marshy water samples, > 0.7 μm), high-molecular-weight iron (0.7-0.05 μm), medium-molecular-weight iron (0.05-0.01 μm), and low-molecular-weight iron (< 0.01 μm). The cross-flow filtration suggested that iron primarily exist in both the > 0.7 μm and < 0.01 μm size fractions in marshy waters. Rainfall is the key for rain-fed wetland to determine fate of iron by changing the aquatic biochemical conditions. By monitoring the variation of iron concentrations and fractions over three years, it was found that dissolved iron and acid-labile iron concentrations exhibit a large variation extent under different annual rainfalls from 2006 to 2008. The seasonal variation for iron species proved that the surface temperature could control some conversion reactions of iron in marshy waters. Low- molecular-weight iron would convert to acid-labile iron gradually with temperature decreasing. The photochemical reactions of iron fractions, especially low-molecular-weight iron had occurred under solar irradiation. The relative proportion of low-molecular-weight in total dissolved iron ranging from 28.3% to 43.2% were found during the day time, which proved that the observed decreasing concentration of acid lability iron was caused by its degradation to low molecular weight iron.Xiaofeng Pan Baixing Yan Muneoki Yoh Lixia Wang Xiuqi Liu 2010Journal of Environmental Sciences2010,22,7:4
17Effects of land use and changes in cover on the transformation and transportation of iron:A case study of the Sanjiang Plain,Northeast China显示文摘Wetland reclamation has been ongoing in the Sanjiang Plain since the mid-1950s,which has resulted in major changes in wetlands and the agriculture ecosystem in the region that have influenced the iron output to the Sea of Okhotsk and limited the primary productivity in the North Pacific Ocean.This study was conducted to investigate the chemical forms of iron in different aquatic environments(agricultural water including groundwater,paddy water,and canal water;wetland water including marsh water,marsh streams,and main streams) with the cross-flow filtration method to reveal the transportation and transformation characteristics of iron in response to major land use changes.In addition,the factors affecting iron behavior in different water bodies were reviewed.In marsh water and streams,the concentrations of dissolved iron were higher due to the high organic matter contents and marsh water becoming the main iron source for river water.The conversion of dissolved iron into acid-labile iron occurred during the discharge of wetland water into marsh rivers.Iron primarily existed in both the >0.7 and <0.01 μm size fractions,accounting for about 58.3% and 26.4% of the total dissolved iron,respectively.In agricultural irrigation systems,ferrous ion entered the paddy fields from groundwater,and a fraction of this ferrous iron was subsequently converted into high molecular weight and medium molecular weight iron(colloid iron) in paddy and canal water.However,the concentrations of total dissolved iron decreased by 62.5% from underground to the surface due to the formation of precipitates.Despite this,water discharge in agriculture is still an important iron source for rivers and has the potential to supplement iron due to its higher acid-labile iron concentrations.Land use and cover change and agricultural irrigation increased the iron content of surface soil,but reduced the output of iron in water systems.Overall,the concentration of total dissolved iron in water systems has been reduced to 42.6% by wetland reclamation.PAN XiaoFeng YAN BaiXing Yoh MUNEOKI 2011Science China Earth Sciences2011,54,5:4
18CD146:a potential therapeutic target For systemic sclerosis显示文摘Dear Editor, Systemic sclerosis (scleroderma,SSc)is a chronic disease of connective tissues,and is clinically characterized by persistent fibrosis in the skin as well as in a variety of organs (Katsumoto et al.,2011).The pathogenesis of SSc is com- plex and involves vasculopathy,autoimmunity and fibrosis. The hallmarks of late-stage SSc are the excessive secretion and accumulation of extracellular matrix (ECM)by aberrantly activated fibroblasts (myofibroblasts)in the skin and internal organs (Bhattacharyya et al.,2012).Lingling Zhang Yongting Luo Xiao Teng Zhenzhen Wu Mengtao Li Dong Xu Qian Wang Fei Wang Jing Feng Xiaofeng Zeng Xiyun Yan 2018Protein & Cell2018,9,12:4
19Structures of the human pre-catalytic spliceosome and its precursor spliceosome显示文摘The pre-catalytic spliceosome (B complex) is preceded by its precursor spliceosome (pre-B complex) and followed by the activated spliceosome (Bact complex). The pre-B-to-B and B-to-Bact transitions are driven by the ATPase/helicases Prp28 and Brr2,respectively. In this study,we report the cryo-electron microscopy structures of the human pre-B complex and the human B complex at an average resolution of 5.7 and 3.8 A,respectively. In the pre-B complex,U1 and U2 small nuclear ribonucleoproteins (snRNPs) associate with two edges of the tetrahedron-shaped U4/U6.U5 tri-snRNP. The pre-mRNA is yet to be recognized by U5 or U6 small nuclear RNA (snRNA),and loop I of U5 snRNA remains unengaged. In the B complex,U1 snRNP and Prp28 are dissociated,the 5’-exon is anchored to loop I of U5 snRNA,and the 5’-splice site is recognized by U6 snRNA through duplex formation. In sharp contrast to S. cerevisiae,most components of U2 snRNP and tri-snRNP,exemplified by Brr2,undergo pronounced rearrangements in the human pre-B-to-B transition. Structural analysis reveals mechanistic insights into the assembly and activation of the human spliceosome.Xiechao Zhan Chuangye Yan Xiaofeng Zhang Jianlin Lei Yigong Shi 2018Cell Research2018,28,12:4
20A versatile photodetector assisted by photovoltaic and bolometric effects显示文摘The advent of low-dimensional materials with peculiar structure and superb band properties provides a new canonical form for the development of photodetectors.However,the limited exploitation of basic properties makes it difficult for devices to stand out.Here,we demonstrate a hybrid heterostructure with ultrathin vanadium dioxide film and molybdenum ditelluride nanoflake.Vanadium dioxide is a classical semiconductor with a narrow bandgap,a high temperature coefficient of resistance,and phase transformation.Molybdenum ditelluride,a typical two-dimensional material,is often used to construct optoelectronic devices.The heterostructure can realize three different functional modes:(i)the p-n junction exhibits ultrasensitive detection(450 nm-2μm)with a dark current down to 0.2 pA and a response time of 17μs,(ii)the Schottky junction works stably under extreme conditions such as a high temperature of 400 K,and(iii)the bolometer shows ultrabroad spectrum detection exceeding 10μm.The flexible switching between the three modes makes the heterostructure a potential candidate for next-generation photodetectors from visible to longwave infrared radiation(LWIR).This type of photodetector combines versatile detection modes,shedding light on the hybrid application of novel and traditional materials,and is a prototype of advanced optoelectronic devices.Wei Jiang Tan Zheng Binmin Wu Hanxue Jiao Xudong Wang Yan Chen Xiaoyu Zhang Meng Peng Hailu Wang Tie Lin Hong Shen Jun Ge Weida Hu Xiaofeng Xu Xiangjian Meng Junhao Chu Jianlu Wang 2020Light(Science & Applications)2020,9,1:3
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