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Nucleosome assembly and epigenetic inheritance

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Protein & Cell 2010年第9期1卷 820-829页

作者： mo xu Bing Zhu Graduate Program Peking Union Medical College and Chinese Academy of Medical SciencesBeijing 100730China National Institute of Biological Sciences Beijing 102206China

In eukaryotic cells,histones are packaged into octameric core particles with DNA wrapping around to form nucleosomes,which are the basic units of chromatin(Kornberg and Thomas,1974).Multicellular organisms utilise chromatin marks to translate one single genome into hundreds of epigenomes for their corresponding cell *** of epigenetic status is critical for the maintenance of gene expression profile during mitotic cell divisions(Allis et al.,2006).During S phase,canonical histones are deposited onto DNA in a replication-coupled manner(Allis et al.,2006).To understand how dividing cells overcome the dilution of epigenetic marks after chromatin duplication,DNA replication coupled(RC)nucleosome assembly has been of great *** this review,we focus on the potential influence of RC nucleosome assembly processes on the maintenance of epigenetic status.

关键词： nucleosome assembly epigenetic inheritance DNA replication coupled

Leaching Behavior of Trace Elements in Coal Spoils from Yangquan Coal Mine, Northern China

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Journal of Earth Science 2016年第5期27卷 891-900页

作者： xubo Gao mo xu Qinhong Hu Yanxin Wang State Key Laboratory of Biogeology and Environmental Geology and School of Environmental Studies China University of GeosciencesWuhan 430074China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection&College of Environment and Civil Engineering Chengdu University of TechnologyChengdu 610059China Department of Earth and Environment Sciences University of Texas at AustinAustin TX76019USA

The long-term dumping of coal waste piles has caused serious environmental problems. Release of trace elements（including rare earth elements, REEs） from coal spoils gobs was investigated at Yangquan coal mine, Shanxi Province, China. X-ray diffraction（XRD） was used to analyze the mineral composition of the coal spoils. The minerals of the coal-spoil samples are mainly kaolinite and quartz, with a minor proportion of pyrite. The batch and column tests were employed to simulate the leaching behavior of trace elements from coal spoils. Elements V, Cr, Zn, As, Pb, and Cd are highly enriched in all coal spoils. The coal spoils also have elevated levels of Ga, Ge, Se, Sn, Hf, and Th. The leachate of coal spoils, fried coal spoils and CSFGM（coal spoils fire gas mineral） samples are acidic, with the p H values ranging between 3.0 and 6.6. The released elements with high concentrations（over 100 μg/L） include Fe, Mn, Co, Ni and Zn, while moderately-released elements are Cu, Se, mo and As. A high content of heavy metals in batch-test leachate with CSFGM indicates an increased mobility of heavy metals in coal spoil combustion byproduct. Within the first hour washing with the electrolyte solution, a rapid rise of common cations, trace elements, and REEs content, as well as a drop of p H value, in effluent was observed. An increased leaching velocity favors the release of trace elements from coal spoils. In addition, the pulse input of precipitation led to more elements to be released than continuous leaching.

关键词： trace elements coal spoil contamination leaching column test.

Highly Stereoselective Synthesis of trans-3-Chloro-β-lactams from Imines and Mixed Chloroacetyl and Nitroacetyl Chlorides

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Chemical Research in Chinese Universities 2011年第6期27卷 958-962页

作者： QI Heng-zhen mo Shan-yan xu Jia-xi State Key Laboratory of Chemical Resource Engineering Department of Organic Chemistry Faculty of Science Beijing University of Chemical Technology Beijing 100029 P. R. China

A series of trans-3-chloro-β-lactams was synthesized stereospecifically from imines and chloroacetyl chloride or a mixture of chloroacetyl chloride and nitroacetyl chloride, prepared from vinylidene chloride and a mixture of concentrated nitric acid and sulfuric acid, in the presence of triethylamine. The reaction of vinylidene chloride and the mixed acid was investigated. The formation mechanism of chloroacetyl chloride and nitroacetyl chloride and their reaction process with imines were proposed.

关键词： β-Lactam Chloroacetyl chloride Staudinger reaction Stereoselectivity

Palladium-catalyzed highly regioselective Heck reaction of aryl nonaflates with electron-rich olefins

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Chinese Chemical Letters 2008年第9期19卷 1017-1020页

作者： Dan xu Zhi Hua Liu Wei Jun Tang Jun mo Li Jin xu Department of Chemistry Renmin University of China Beijing 100872 China

Highly efficient palladium-catalyzed Heck coupling of aryl nonaflates with electron-rich vinyl ethers, and enamides is described. These reactions afforded exclusively the branched products in good yields. The results ... 详细信息

关键词： Aryl nonaflates Electron-rich Palladium Heck reaction Regioselectivity

Reservoir Regulation for Control of an Ancient Landslide Reactivated by Water Level Fluctuations in Heishui River,China

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Journal of Earth Science 2020年第6期31卷 1058-1067页

作者： Jian Guo mo xu Qiang Zhang Xianxuan Xiao Shishu Zhang Shaoming He State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China PowerChina Chengdu Engineering Corporation Limited Chengdu 610072China

Due to the complex geological processes of Qinghai-Tibet Plateau,numerous deposits,especially the large-scale ancient landslide deposits,are characteristic features of the valleys incised in southwestern *** water level fluctuations since 2011 in Maoergai Reservoir,China,registered the reactivation of Xierguazi ancient landslide,and presented a significant risk to neighboring *** on detailed field survey and drilling exploration,the landslide was divided into Zone A and Zone B,and other characterizations of landslide were studied as *** precisely measure the extent of landslide displacement during filling and drawdown stage,surface displacement monitoring system was deployed on the *** monitoring analyses data reveal that reservoir fluctuation is the dominant factor influencing landslide displacement,especially during drawdown ***,a future sliding is anticipated in Zone A,while a creep had already existed in Zone B.A reservoir regulation was then established using the lead-lag correlation between reservoir fluctuation and landslide displacement and landslide stability *** the end,the follow-up deformation monitoring demonstrates that the reservoir regulation controlled the landslide *** control by reservoir regulation in Maoergai can serve as a case study for other settlements involved in similar construction activities.

关键词： ancient landslide reactivation reservoir regulation displacement monitoring correlation analysis

Developing a risk assessment system for gas tunnel disasters in China

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Journal of mountain Science 2017年第9期14卷 1751-1762页

作者： KANG Xiao-bing LUO Sheng LI Qing-shan xu mo LI Qiang State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of Technology College of Engineering Sichuan Normal University

Gas disasters always restrict the tunnel constructions in mountain area, which becomes a major geological barrier against the development of underground engineering. China is rich in coal resources and has a large amount of gas with a wide range of distribution. However, China experienced not only adverse effects on coal mining but also gas disasters in underground engineering construction, such as tunnels and chambers. With the increased number of tunnels passing through coal-bearing strata, the incidence of gas accidents is also rising. Therefore, the significance of preventing and mitigating gas disasters should be emphasized, and an effective risk assessment method for gas disasters should be established. On the basis of research on over 100 gas tunnels in China, a relatively ideal gas disaster risk assessment method and system for tunnels are established through the following measures. Firstly, geo-environmental conditions and gas situations were analyzed during construction. Secondly, qualitative analysis was combined with quantitative analysis. Finally, the influencing factors of gas disasters, including geological conditions, gas,and human factors, were investigated. The gas tunnel risk assessment system includes three levels:(1) the grading assessment of a gas tunnel during the planning stage,(2) the risk assessment of gas tunnel construction during the design and construction stages,(3) the gas tunnel outburst risk assessment during the coal uncovering stage. This system was applied to the dynamic assessment of gas disaster during the construction of the Zipingpu tunnel of Dujiangyan–Wenchuan Highway(in Sichuan, Southwest China). The assessment results were consistent with the actual excavation, which verified the rationality and feasibility of the system. The developed system was believed to be back-up and applied for risk assessment of gas disaster in the underground engineering construction.

关键词： Tunnel engineering Gas disasters Risk assessment Index system Zipingpu tunnel

Effect of Management Practices on Seasonal Dynamics of Organic Carbon in Soils Under Bamboo Plantations

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Pedosphere 2006年第4期16卷 525-531页

作者： ZHOU Guo-mo xu Jian-Ming JIANG Pei-Kun College of Resources and Environment Zhejiang University Hangzhou 31002g （China） Zhejiang Forest College Lin＇an 311300 （China）

Soil samples for conventional management (CM) and intensive management (IM) practices were taken over a year at 2-month intervals to determine the effect of management practices on soil organic carbon (SOC) and to quantify seasonal dynamics in SOC for bamboo (Phyllostachys pubescens Mazel ex H. de Lehaie) stands. The results with IM compared to CM showed large decreases in total organic carbon (TOC), microbial biomass carbon (MBC), water-soluble organic carbon (WSOC), and the MBC/TOC ratio in the soils. With all IM plots in the 0-20 cm depth across sampling periods, average decreases compared with CM were: TOC, 12.1%; MBC, 26.1%; WSOC, 29.3%; the MBC/TOC ratio, 16.1%; and the WSOC/TOC ratio, 20.0%. Due to seasonal changes of climate, seasonal variations were observed in MBC and WSOC. Soil MBC in the 0-20 cm depth in September compared to May were 122.9% greater for CM and 57.6% greater for IM. However, due primarily to soil temperature, soil MBC was higher during the July to November period, whereas because of soil moisture, WSOC was lower in July and January. This study revealed that intensive management in bamboo plantations depleted the soil C pool; therefore, soil quality with IM should be improved through application of organic manures.

关键词： bamboo (Phyllostachys pubescens) conventional management dynamics intensive management soil organic carbon

Three-Dimensional Radiation in Absorbing-Emitting Scattering Medium Using the Discrete-OrdinatesApproximation

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Journal of Thermal Science 1998年第4期7卷 255-263页

作者： Xiao-Lin Wei Tong-mo xu Shi-En Hui Institute of Mechanics Chinese Academy of Sciences Beijing China Department of Thermal Engineering Xi’an Jiaotong University China

The discrete-ordinates method is a simple, accurate and of little computational time solution to predict the radiative heat transfer in the combustion chambers. In this paperl three-dimension radiative problems for absorbing-emitting-scattering medium are modeled using this method in the rectangular enclosure. And in addition, new discrete-ordinates are developed to study the absorbing-emitting-scattering radiation processes for complex phase function. The reasonable results can be obtained through these new ordinates, yet the deviated results are only obtained through conventional Sn ordinates.

关键词： radiation discrete-ordinates method phase function

UHPC-窄幅钢箱组合梁抗剪承载力计算方法

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科学技术与工程 2025年第3期25卷 1180-1187页

作者：黄荆莫时旭郑艳长安大学建筑工程学院西安710000 桂林理工大学土木与建筑工程学院桂林541004 广西建筑新能源与节能重点实验室桂林541004

为改善组合梁负弯矩区易开裂的问题,提出超高性能混凝土-窄幅钢箱组合梁结构,基于极限平衡法以及分项叠加法得到了UHPC-窄幅钢箱组合梁抗剪承载力计算方法。为验证计算方法的准确性,以超高性能混凝土(ultra-high performance concrete,U... 详细信息

为改善组合梁负弯矩区易开裂的问题,提出超高性能混凝土-窄幅钢箱组合梁结构,基于极限平衡法以及分项叠加法得到了UHPC-窄幅钢箱组合梁抗剪承载力计算方法。为验证计算方法的准确性,以超高性能混凝土(ultra-high performance concrete,UHPC)层厚度以及钢纤维为变量,设计了1根普通混凝土窄幅钢箱组合梁和3根UHPC-窄幅钢箱组合梁试件,对试验梁进行跨中反向加载试验,得到组合梁负弯矩下的抗剪性能。试验结果表明,相比于普通混凝土窄幅钢箱组合梁,当翼板采用UHPC材料时,翼板中的裂缝分布较为规律,且随着UHPC板厚度的增加,裂缝的分布逐渐呈现竖向等间距分布的特点,当保持翼板的厚度不变,将UHPC层厚度增加50 mm,其屈服荷载增加12.5%,极限荷载增加8.3%,极限荷载对应的挠度值减小了22%。通过分析各试件的屈服挠度以及极限挠度可知,随着UHPC翼板厚度的增加,屈服挠度有逐渐增大的趋势,组合梁弹性阶段所占的比例不断增加。将试验数据与理论计算结果对比分析表明,采用分项叠加法所得的计算结果更能有效地反映UHPC层、普通混凝土层、钢箱、配筋以及充填部分混凝土对于抗剪承载力的贡献,且结果较为精确。

关键词：超高性能混凝土抗剪承载力组合梁负弯矩