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Remote Chirality Transfer through Medium Cycle Formation/Intramolecular Hydride Transfer Cascade

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Chinese Journal of Chemistry 2020年第3期38卷 305-306页

作者： juan Chend Bo liu Analytical&Testing Center Sichuan UniversityChengduSichuan 610064China Key Laboratory of Green Chemistry&Technology of Ministry of Education College of ChemistrySichuan UniversityChengduSichuan 610064China

Intramolecular hydride transfer has long been recognized as a powerful method to gen-erate new stereogenic centers induced by the existing stereogenic center(s).Synthetical-ly significant selectivities are usually obtained through 1,5-hydride transfer within six-membered *** mini-review focuses on a transannular hydride transfer generating up to three stereocenters simultaneously from a single stereogenic center through for-mation of medium rings,mostly eight-membered rings,in mild reaction *** corresponding linear products with multiple stereocenters are potentially useful building blocks for synthesis of complex molecules including polyketide natural products.

关键词： hydride centers transfer

Assimilation of Chinese Fengyun-3B Microwave Temperature Sounder radiances into the Global GRAPES system with an improved cloud detection threshold

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Frontiers of Earth Science 2016年第1期10卷 145-158页

作者： juan LI Guiqing liu Numerical Weather Prediction Center China Meteorological Administration Beijing 100081 China National Meteorological Center China Meteorological Administration Beijing 100081 China

Fengyun-3B （FY-3B） is the second polar- orbiting satellite in the new Fengyun-three series. This paper describes the assimilation of the FY-3B Microwave Temperature Sounder （MWTS） radiances in the Chinese Numerical Weather prediction system - the Global and Regional Assimilation and PrEdiction System （GRAPES）. A quality control procedure for the assimilation of the FY- 3B MWTS radiance was proposed. Extensive monitoring before assimilation shows that the observations of channel 4 are notably contaminated. channels 2 and 3 are used in this research. A cloud detection algorithm with an improved cloud-detection threshold is determined and incorporated into the impact experiments. The clear field- of-view （FOV） percentage increased from 42% to 57% with the new threshold. In addition, the newly added FOVs are located in the clear region, as demonstrated by the cloud liquid water path data from NOAA-18. The impact of the MWTS radiances on the prediction of GRAPES was researched. The observation biases ofFY-3B MWTS O-B （differences between satellite observations and model simulations） significantly decreased after an empirical bias correction procedure. After assimilation, the residual biases are small. The assimilation of the FY-3B MWTS radiances shows a positive impact in the Northern Hemisphere and a neutral impact in the Southern Hemisphere.

关键词： Fengyun-3B (FY-3B) MWTS quality control GRAPES

Cholesterol metabolism and homeostasis in the brain

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Protein & Cell 2015年第4期6卷 254-264页

作者： juan Zhang Qiang liu Chinese Academy of Sciences Key Laboratory of Brain Function and Disease and School of Life Sciences University ofScience and Technoloqv of China. Hefei 230026. China

Cholesterol is an essential component for neuronal physiology not only during development stage but also in the adult life. Cholesterol metabolism in brain is in- dependent from that in peripheral tissues due to blood- brain barrier. The content of cholesterol in brain must be accurately maintained in order to keep brain function well. Defects in brain cholesterol metabolism has been shown to be implicated in neurodegenerative diseases, such as Alzheimer＇s disease （AD）, Huntington＇s disease （HD）, Parkinson＇s disease （PD）, and some cognitive deficits typical of the old age. The brain contains large amount of cholesterol, but the cholesterol metabolism and its complex homeostasis regulation are currently poorly understood. This review will seek to integrate current knowledge about the brain cholesterol metabo- lism with molecular mechanisms.

关键词： cholesterol metabolism homeostasis,apoE

流通式-时间分辨分析技术在地质领域的应用进展

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岩矿测试 2025年第1期44卷 1-18页

作者：许心宁王朔徐娟刘鹏飞杨守业同济大学海洋地质国家重点实验室上海200092

流通式-时间分辨分析系统(简称FT-TRA)是二十一世纪初新发展起来的一种快速反应(溶解)-在线分析系统,由淋洗液混合单元、反应单元与分析单元组成,核心功能是通过特定流动相淋洗样品池中的微量样品,分离或去除样品中的特定组分,并监测样... 详细信息

流通式-时间分辨分析系统(简称FT-TRA)是二十一世纪初新发展起来的一种快速反应(溶解)-在线分析系统,由淋洗液混合单元、反应单元与分析单元组成,核心功能是通过特定流动相淋洗样品池中的微量样品,分离或去除样品中的特定组分,并监测样品不同元素和矿物组分的出溶特征,实现高分辨的在线过程分析。本文综述了FT-TRA系统的技术原理与软硬件组成、实验方法与操作要点及地质应用发展过程,重点对该系统在地质应用过程中出现的争议点进行阐释与分析,并基于其发展现状展望其未来发展方向与潜力。FT-TRA系统目前主要的地质应用包括古海洋学与古环境学研究代用指标的验证(如有孔虫、介形虫淋洗)、矿物溶解过程与反应动力学研究、环境样品的元素相态分析等。FT-TRA系统以溶解并提取有孔虫/介形虫壳体的元素组成信号作为还原古海洋指标的重要手段,与传统批处理法相比,该方法被认为具有实时监测清洁程度、降低损失率并实现差异溶解的优势,能够获取更精细的壳体化学组成信息;测试矿物溶解态与溶解参数也是FT-TRA系统的重要功能之一,该系统的实验室模拟能够与模型结合探究不同类型矿物在稳态下的溶解动力学,为研究矿物在自然状态下的溶解过程提供启示;近些年来该系统还逐渐被用于矿物反应性测试,其中将气相CO_(2)作为淋滤液与矿物反应的研究可能在全球变暖及CO_(2)的人工捕捉课题上具有潜在应用价值。FT-TRA系统运行中涉及的不同组分的溶解机制是其应用过程中亟待解决的重要问题,进一步完善其溶解动力学原理必然将为该系统的未来发展提供更多如多类型地质样品溶解、矿物的模拟合成等新思路。

关键词：流通式-时间分辨分析系统(FT-TRA) 在线地球化学分析地质应用环境研究

Sparse Weighted Canonical Correlation Analysis

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Chinese Journal of Electronics 2018年第3期27卷 459-466页

作者： MIN Wenwen liu juan ZHANG Shihua State Key Laboratory of Software Engineering School of Computer Wuhan University National Center for Mathematics and Interdisciplinary Sciences Academy of Mathematics and Systems Science Chinese Academy of Sciences School of Mathematics Sciences University of Chinese Academy of Sciences

Given two data matrices X and Y, Sparse canonical correlation analysis（SCCA） is to seek two sparse canonical vectors u and v to maximize the correlation between Xu and Yv. Classical and sparse Canonical correlation analysis（CCA） models consider the contribution of all the samples of data matrices and thus cannot identify an underlying specific subset of samples. We propose a novel Sparse weighted canonical correlation analysis（SWCCA）,where weights are used for regularizing different *** solve the L;-regularized SWCCA（L;-SWCCA） using an alternating iterative algorithm. We apply L;-SWCCA to synthetic data and real-world data to demonstrate its effectiveness and superiority compared to related methods. We consider also SWCCA with different penalties like Least absolute shrinkage and selection operator（LASSO）and Group LASSO, and extend it for integrating more than three data matrices.

关键词： Canonical correlation analysis(CCA) Sparse canonical correlation analysis(SCCA) Sparse weighted CCA(SWCCA) Group LASSO regularized SWCCA Multi-view SWCCA

Atmospheric density determination using high-accuracy satellite GPS data

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Science China(Technological Sciences) 2018年第2期61卷 204-211页

作者： REN TingLing MIAO juan liu SiQing National Space Science Center Chinese Academy of SciencesBeijing 100190China College of Earth Sciences University of Chinese Academy of SciencesBeijing 100049China

Atmospheric drag is the main source of error in the determination and prediction of the orbit of low Earth orbit （LEO） satellites; however, empirical models that are used to account for this often have density errors of around 15%-30%. Atmospheric density determination has thus become an important topic for researchers. Based on the relationship between file atmospheric drag force and the decay of the semi-major axis of the orbit, we derived atmospheric density along the trajectory of challenging mini-satellite payload （CHAMP） satellite with its rapid science orbit （RSO） data. Three primary parameters--the ratio of cross-sectional area to mass, the drag coefficient, and the decay of the semi-major axis caused by atmospheric drag--were calculated. We also analyse the source of the error and made a comparison between the GPS-derived and reference density. The result for December 2, 2008, showed that the mean error of the GPS-derived density could be decreased from 29.21% to 9.20%, if the time span adopted for the process of computation was increased from 10 min to 50 min. The result for the entire month of December indicated that a density precision of 10% could be achieved, when the time span meets the condition that the amplitude of the decay of the semi-major axis is much greater than its standard deviation.

关键词： atmospheric density determination high-accuracy GPS data drag coefficient orbit decay

Structural and functional analysis of an asymmetric bidirectional promoter in Arabidopsis thaliana

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Journal of Integrative Plant Biology 2015年第2期57卷 162-170页

作者： Shi-juan liu Qiu-juan Yue Wei Zhang Key Laboratory of Plant Cell Engineering and Germplasm Innovation Ministry of Education School of Life Sciences Shandong University College of Life Science Qufu Normal University

Bidirectional promoters are relatively abundant in eukaryotic genomes, suggesting that they have an important biological significance. As yet, few of these promoters have been characterized in detail. Here, using a promoter：：GUS transgene approach has revealed that the intergenic region of Arabidopsis thaliana divergent genes At1g71850 and At1g71860 is an asymmetric bidirectional promoter, which exhibits an orientation-dependent expression profile. The strength of the forward promoter was greater than that of the reverse promoter, and their tissue specificities were not identical. Deletion analyses revealed that this bidirectional promoter could be divided into three functional regions. The basal level and tissue specificity of the promoter in the reverse orientation were regulated positively by region II and negatively by region III, whereas promoter activity in the forward orientation was regulated negatively by region II and positively by region I. Thus the 52-bp stretch of region II had a dual function, enhancing expression in the reverse orientation and suppressing it in the forward orientation. These results demonstrated that the activity of the At1g71850-At1g71860 bidirectional promoter was modulated by complex interactions between both positive and negative cis-acting elements. These findings will enhance our understanding of the regulatory mechanisms of plant bidirectional promoters.

关键词： GUS (β-glucuronidase) positive and negative regulatoryelement promoter strength tissue-specific expression

Sparse recovery method for far-field and near-field sources localization using oblique projection

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The Journal of China Universities of Posts and Telecommunications 2013年第3期20卷 90-96页

作者： WANG Bo ZHAO Yan-ping liu juan-juan College of Communication Engineering Jilin University

In this paper, we propose a novel source localization method to estimate parameters of arbitrary field sources, which may lie in near-field region or far-field region of array aperture. The proposed method primarily constructs two special spatial-temporal covariance matrixes which can avoid the array aperture loss, and then estimates the frequencies of signals to obtain the oblique projection matrixes. By using the oblique projection technique, the covariance matrixes can be transformed into several data matrixes which only contain single source information, respectively. At last, based on the sparse signal recovery method, these data matrixes are utilized to solve the source localization problem. Compared with the existing typical source localization algorithms, the proposed method improves the estimation accuracy, and provides higher angle resolution for closely spaced sources scenario. Simulation results are given to demonstrate the performance of the proposed algorithm.

关键词： array signal processing near-field far-field sparse signal recovery oblique projection

Advances in innate immune signaling:new activators and regulators

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National Science Review 2016年第2期3卷 160-162页

作者： juan liu Xuetao Cao National Key Laboratory of Medical Immunology & Institute of Immunology Second Military Medical University National Key Laboratory of Medical Molecular Biology & Department of Immunology Institute of Basic Medical SciencesChinese Academy of Medical Sciences

The innate immune system can detect the invading microbe components via three major pattern recognition receptorsToll-like receptors,RIG-I-like receptors and NOD-like receptors as well as a variety of cytoplasmic DNA or RNA *** innate receptors induce a series of intracellular downstream signaling pathways,leading to the efficient innate immune responses to eliminate pathogens(Fig.1).Meanwhile,

关键词： Advances in innate immune signaling IKK DNA TLR