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Zinc isotopic behavior of mafic rocks during continental deep subduction

Geoscience Frontiers 2021年第5期12卷 182-191页

作者： Li-juan xu Sheng-Ao Liu Shuguang Li State Key Laboratory of Geological Processes and Mineral Resources School of Scientific ResearchChina University of GeosciencesBeijing 100083China

Zinc isotopes may act as a new tool of tracking recycling of crustal materials that causes compositional heterogeneity of the *** application relies on an investigation of Zn isotopic behaviors during slab *** this study,we report Zn isotopic compositions for a suite of metabasalts(greenschists,amphibolites,and coesitebearing eclogites)from the Dabie Orogen(China),which were formed via the subduction of mafic rocks into different depths and up to>200 *** out of eight greenschists are characterized by lighterδ^(66)ZnJMC-Lyon(0.10‰-0.16‰)than those of global basalts(0.28‰±0.05‰),which may be caused by crustal assimilation of the protoliths by sedimentary rocks due to their extremely high ^(87)Sr/^(86)Sr(up to 0.7130)and lowεNd values(down to−12.3).The remaining greenschists have relatively low ^(87)Sr/^(86)Sr and theirδ66Zn values(0.21‰-0.38‰)overlap the ranges of amphibolites(0.18‰-0.32‰)and coesite-bearing eclogites(0.18‰-0.36‰).There is no correlation betweenδ^(66)Zn and sensitive indicators of dehydration(Rb/TiO_(2),Ba/Yb,and H_(2)O+),suggesting that no detectable Zn isotope fractionation has occurred during the deep subduction of mafic rocks even into>200 km,which is attributed to the limited loss of Zn during prograde metamorphism and ***,Zn isotopic compositions of the deeply subducted mafic rocks are inherited from their *** that these metamorphosed rocks have higherδ66Zn than that of the mantle value by up to 0.2‰,the recycled/subducted mafic crust can incorporate isotopically heavy Zn into the *** subducted slabs may partially melt and generate a metasomatized mantle,resulting in changes of Zn isotopic composition of the hybridized mantle as have been observed in some mantle xenoliths and basaltic lavas.

关键词： Zn isotopes Metamorphosed rocks Dehydration Crustal deep subduction

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多光谱法研究二氢杨梅素对胰脂肪酶的抑制作用

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光谱学与光谱分析 2025年第1期45卷 107-116页

作者：孟晓慧黄旭波夏张晨徐娟王衍彬程俊文杨柳贺亮浙江省森林资源生物与化学利用重点实验室浙江省林业科学研究院浙江杭州310023 浙江省特色中药资源保护与创新利用重点实验室浙江农林大学食品与健康学院浙江杭州311300

藤茶中主要黄酮类物质——二氢杨梅素(DMY)具有多种生物活性,而其降血脂机理鲜有报道。采用紫外光谱研究了DMY对胰脂肪酶(PL)的抑制作用,结合荧光光谱、同步荧光光谱、三维荧光光谱及分子对接模拟法研究了二者之间的相互作用及机理。紫... 详细信息

藤茶中主要黄酮类物质——二氢杨梅素(DMY)具有多种生物活性,而其降血脂机理鲜有报道。采用紫外光谱研究了DMY对胰脂肪酶(PL)的抑制作用,结合荧光光谱、同步荧光光谱、三维荧光光谱及分子对接模拟法研究了二者之间的相互作用及机理。紫外光谱测得DMY对PL的半抑制浓度为2.6×10^(-4)mol·L^(-1),表明其对PL具有较好的抑制作用,采用Lineweaver-Burk方程得出该抑制剂为竞争性作用,其抑制常数为6×10^(-4)mol·L^(-1);通过Stern-Volmer方程和静态猝灭双对数公式对293和310 K两者互作的荧光光谱计算,结果表明DMY能猝灭PL的自发荧光,荧光猝灭方式为静态猝灭,猝灭常数K_(SV)与温度负相关;结合常数K a与温度正相关,结合位点数n约为1,说明DMY与PL结合并形成稳定的配位复合物;采用Van't Hoff方程求出结合过程中的热力学参数ΔS=0.2014 J·mol^(-1)·K^(-1),ΔH=32.311 kJ·mol^(-1),ΔG小于0,表明两者通过疏水作用力自发结合且放热;由F rster非辐射能量转移理论计算出结合距离r=1.475 nm,说明DMY与PL结合生成复合物时发生了非辐射能量转移;同步荧光光谱结果表明,DMY与PL的相互作用对PL的二级构象发生了明显改变,主要作用于色氨酸(Tyr)附近。紫外光谱进一步揭示DMY可使PL发生π→π跃迁,导致其氨基酸残基的微环境变化;三维荧光光谱显示DMY可使PL两个特征峰(peak1,peak2)分别红移10和5 nm,荧光强度分别下降51.38%和41.93%,证实两者发生疏水作用后PL的微环境极性增大,构象改变;分子对接模拟结果表明,DMY结合位点位于PL中由PHE77、PHE215、TYR114、ILE209、PRO180氨基酸形成的疏水口袋内,其A环C5、B环C4′、C环C3、C环C O的-OH分别与氨基酸HIS263、TYR114、SER152、PHE215形成氢键,与氨基酸LRU213、GLU179、ALA178、THR78产生范德华力。实验数据有助于深入解DMY的降血脂分子作用机制,其独特的结构为天然抑制剂的药物合成和筛选提供了理论依据。

关键词：二氢杨梅素胰脂肪酶多光谱法分子对接模拟

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A Marine Environment Early Warning Algorithm Based on Marine Data Sampled by Multiple Underwater Gliders

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China Ocean Engineering 2019年第2期33卷 172-184页

作者： xu Zhen-zhen LI Lu YU Jian-cheng xu Xiu-juan JIA Ming-fei School of Software Technology Dalian University of Technology The State Key laboratory of Robotics Shenyang Institute of AutomationCAS

This study analyzes and summarizes seven main characteristics of the marine data sampled by multiple underwater gliders. These characteristics such as the big data volume and data sparseness make it extremely difficult to do some meaningful applications like early warning of marine environment. In order to make full use of the sea trial data, this paper gives the definition of two types of marine data cube which can integrate the big marine data sampled by multiple underwater gliders along saw-tooth paths, and proposes a data fitting algorithm based on time extraction and space compression(DFTS) to construct the temperature and conductivity data cubes. This research also presents an early warning algorithm based on data cube(EWDC) to realize the early warning of a new sampled data *** results show that the proposed methods are reasonable and effective. Our work is the first study to do some realistic applications on the data sampled by multiple underwater vehicles, and it provides a research framework for processing and analyzing the big marine data oriented to the applications of underwater gliders.

关键词： big marine data early warning marine environment underwater gliders

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Study on segmented distribution for reliability evaluation

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Chinese Journal of Aeronautics 2017年第1期30卷 310-329页

作者： Li Huaiyuan Zuo Hongfu Su Yan xu juan Yin Yibing School of Software Engineering Jinling Institute of Technology College of Civil Aviation Nanjing University of Aeronautics and Astronautics

In practice, the failure rate of most equipment exhibits different tendencies at different stages and even its failure rate curve behaves a multimodal trace during its life cycle. As a result,traditionally evaluating the reliability of equipment with a single model may lead to severer ***, if lifetime is divided into several different intervals according to the characteristics of its failure rate, piecewise fitting can more accurately approximate the failure rate of equipment. Therefore, in this paper, failure rate is regarded as a piecewise function, and two kinds of segmented distribution are put forward to evaluate reliability. In order to estimate parameters in the segmented reliability function, Bayesian estimation and maximum likelihood estimation（MLE） of the segmented distribution are discussed in this paper. Since traditional information criterion is not suitable for the segmented distribution, an improved information criterion is proposed to test and evaluate the segmented reliability model in this paper. After a great deal of testing and verification,the segmented reliability model and its estimation methods presented in this paper are proven more efficient and accurate than the traditional non-segmented single model, especially when the change of the failure rate is time-phased or multimodal. The significant performance of the segmented reliability model in evaluating reliability of proximity sensors of leading-edge flap in civil aircraft indicates that the segmented distribution and its estimation method in this paper could be useful and accurate.

关键词： Bayesian estimates Gibbs sampling method Maximum likelihood estima-tion Proximity sensors in leadingedge flap in aircraft Reliability Segmented distribution Weibull distribution

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Two New Furostanol Saponins from Tribulus Terrestris L.

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Chemical Research in Chinese Universities 2010年第1期26卷 46-49页

作者： xu Ya-juan xu Tun-hai XIE Sheng-xu SI Yun-shan xu Dong-ming Institute of Traditional Chinese Medicine Academy of Traditional Chinese Medicine and Material Mediea of Jilin Province Changchun 130021 P. R. China Department of Traditional Chinese Medicine Chemistry School of Traditional Chinese Medicine Beijing University of Chinese Medicine Beijing 100102 P. R China Traditional Chinese Medicine College Tianjin University of Traditional Chinese Medicine Tianjin 300193 P R. China

Two new furostanol glucosides, named tribufurosides G and H, were isolated from Tribulus terrestris L. The structures of the two new furostanol glucosides were elucidated as 26-O-β-D-glucopyranosyl-（25R）-5α-furost12-one-3β,22α,26-tetraol-3-O-β-D-glucopyranosyl-（ 1→2 ）-β-D-glucopyranosyl-（ 1→4 ）-β-D-galactopyranoside（ 1 ） and 26-O-β-D-glucopyranosyl-（25S）-5 α- 12-one-2 α,3,8,22 α,26-tetraol-3 -O-β-D-glucopyranosyl-（ 1 → 2 ）-β-D-glucopyranosyl-（1→4）-β-D-galactopyranoside（2） by 1 D, 2D NMR techniques, ESI-MS analysis as well as chemical methods.

关键词： Tribulus terrestris L. Furostanol saponin Tribufurosides G and H

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Visual inspection of aircraft skin:Automated pixel-level defect detection by instance segmentation

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Chinese Journal of Aeronautics 2022年第10期35卷 254-264页

作者： Meng DING Boer WU juan xu Abdul Nasser KASULE Hongfu ZUO College of Civil Aviation Nanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Civil Aircraft Health Monitoring and Intelligent Maintenance of CAAC Nanjing 210016China

Skin defect inspection is one of the most significant tasks in the conventional process of aircraft *** paper proposes a vision-based method of pixel-level defect detection,which is based on the Mask Scoring ***,an attention mechanism and a feature fusion module are introduced,to improve feature ***,a new classifier head—consisting of four convolutional layers and a fully connected layer—is proposed,to reduce the influence of information around the area of the ***,to evaluate the proposed method,a dataset of aircraft skin defects was constructed,containing 276 images with a resolution of 960×720 *** results show that the proposed classifier head improves the detection and segmentation accuracy,for aircraft skin defect inspection,more effectively than the attention mechanism and feature fusion *** with the Mask R-CNN and Mask Scoring R-CNN,the proposed method increased the segmentation precision by approximately 21%and 19.59%,*** results demonstrate that the proposed method performs favorably against the other two methods of pixellevel aircraft skin defect detection.

关键词： Aircraft skin Automatic non-destructive testing Defect inspection Instance segmentation Machine vision

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An Approach to Analyze Physical Memory Image File of Mac OS X

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Journal of Harbin Institute of Technology(New Series) 2014年第4期21卷 116-120页

作者： Li-juan xu Lian-Hai Wang Shandong Provincial Key Laboratory of Computer Network Shandong Computer Science Center( National Supercomputer Center in Jinan)

Memory analysis is one of the key techniques in computer live forensics. Especially,the analysis of a Mac OS X operating system's memory image file plays an important role in identifying the running status of an apple computer. However,how to analyze the image file without using extra"mach-kernel"file is one of the unsolved difficulties. In this paper,we firstly compare several approaches for physical memory acquisition and analyze the effects of each approach on physical memory. Then,we discuss the traditional methods for the physical memory file analysis of Mac OS X. A novel physical memory image file analysis approach without using extra"mach-kernel"file is proposed base on the discussion. We verify the performance of the new approach on Mac OS X 10. 8. 2. The experimental results show that the proposed approach is simpler and more practical than previous ones.

关键词： computer forensics live forensics Mac OS X operating system physical memory analysis

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A New Sequential Systems of Linear Equations Algorithm of Feasible Descent for Inequality Constrained Optimization

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Acta Mathematica Sinica,English Series 2010年第12期26卷 2399-2420页

作者： Jin Bao JIAN Dao Lan HAN Qing juan xu College of Mathematics and Infornation Science Guangxi University Nanning 530004 P. R. China College of Mathematics and Computer Science Guangxi University for NationalitiesNanning 530006 P. R. China College of Electrical Engineering Guangxi University Nanning 530004 P. R. China Department of Mathematics Shanghai University Shanghai 200444 P. R. China College of Mathematical Science Guangxi Teachers Education University Nanning 530001 P. R. China

Based on a new efficient identification technique of active constraints introduced in this paper, a new sequential systems of linear equations （SSLE） algorithm generating feasible iterates is proposed for solving nonlinear optimization problems with inequality constraints. In this paper, we introduce a new technique for constructing the system of linear equations, which recurs to a perturbation for the gradients of the constraint functions. At each iteration of the new algorithm, a feasible descent direction is obtained by solving only one system of linear equations without doing convex combination. To ensure the global convergence and avoid the Maratos effect, the algorithm needs to solve two additional reduced systems of linear equations with the same coefficient matrix after finite iterations. The proposed algorithm is proved to be globally and superlinearly convergent under some mild conditions. What distinguishes this algorithm from the previous feasible SSLE algorithms is that an improving direction is obtained easily and the computation cost of generating a new iterate is reduced. Finally, a preliminary implementation has been tested.

关键词： Inequality constraints nonlinear optimization systems of linear equations global conver-gence superlinear convergence

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New steroidal alkaloid and furostanol glycosides isolated from Solanum lyratum with cytotoxicity

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Chinese Journal of Natural Medicines 2018年第7期16卷 499-504页

作者： xu Yun-Ling LV Jia WANG Wei-Fang LIU Yue xu Ya-juan xu Tun-Hai School of Chinese Pharmacy Beijing University of Traditional Chinese Medicine Key Laboratory of Effective Substances of Traditional Chinese Medicine Jilin Academy of Chinese Medicine Sciences School of Traditional Chinese Medicine Changchun University of Traditional Chinese Medicine

Two previously undescribed steroidal compounds, 16, 23-epoxy-22, 26-epimino-cholest-22(N), 23, 25(26)-trien-3β-ol-3-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl-(1→4)-β-D-galactopyranoside(1) and 26-O-β-D-glucopyranosyl-(25 R)-5α-furost-20(22)-en-3β, 26-diol(2), together with 7 known ones including 26-O-β-D-glucopyranosyl-(25 R)-5, 20(22)-dien-furost-3β, 26-diol(3),(25 R)-5-en-spirost-3β-ol-O-β-D-glucopyranosyl-(1→4)-[α-L-rhmanopyranosyl-(1→2)]-β-D-galactopyranoside(4), funkioside D(5), aspidistrin(6), tigogenin-3-O-β-D-lucotrioside(7), desglucolanatigonin II(8), and degalactotigonin(9), were isolated from Solanum lyratum Thunb. Their cytotoxic activities were tested in two cancer cell lines by MTT method. One of the steroidal glycosides(6) showed significant cytotoxic activity against gastric cancer SGC7901 and liver cancer BEL-7402 cells.

关键词： Steroidal alkaloid Furostanol glycoside Solanum lyratum Cytotoxic activity

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Induction ofγ-aminobutyric acid plays a positive role to Arabidopsis resistance against Pseudomonas syringae^°°

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Journal of Integrative Plant Biology 2020年第11期62卷 1797-1812页

作者： Xiangxiong Deng xuwen xu Yu Liu Yan Zhang Liuyi Yang Shuqun Zhang juan xu State Key Laboratory of Plant Physiology and Biochemistry College of Life SciencesZhejiang UniversityHangzhou 310058China Division of Biochemistry University of MissouriColumbiaMissouri 65211USA

Gamma-aminobutyric acid(GABA)is an important metabolite which functions in plant growth,development,and stress ***,its role in plant defense and how it is regulated are largely ***,we report a detailed analysis of GABA induction during the resistance response to Pseudomonas syringae in Arabidopsis *** searching for the mechanism underlying the pathogen-responsive mitogenactivated protein kinase(MPK)3/MPK6 signaling cascade in plant immunity,we found that activation of MPK3/MPK6 greatly induced GABA biosynthesis,which is dependent on the glutamate decarboxylase genes GAD1 and *** with Pseudomonas syringae pv tomato DC3000(Pst)and Pst-avrRpt2 expressing the civrRpt2 effector gene induced GACH and GAD4 gene expression and increased the levels of *** evidence revealed that GAD1,GAD2,and GAD4 play important roles in bothGABA biosynthesis and plant resistance in response to Pst-avrRpt2 *** gad1/2/4 triple and gad1/2/4/5 quad-ruple mutants,in which the GABA levels were extremelylow,were more susceptible to both Pst and *** loss of MPK3/MPK6,or their upstream MKK4/MKK5,or their downstream substrate WRKY33 sup-pressed the induction of GAD1 and GAD4 expression afterPst-avrRpt2 *** findings shed light on both theregulation and role of GABA in the plant immunity to abacterial pathogen.

关键词： resistance Arabidopsis immunity

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