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Cloning, expression and biocharacterization of OfCht5, the chitinase from the insect Ostrinia furnacalis

Insect Science 2013年第2期20卷 147-157页

作者： Qingyue wu tian Liu Qing Yang Department of Bioscience and Biotechnology Dalian University of Technology Dafian China

Chitinase catalyzes β,4-glycosidic linkages in chitin and has attracted re- search interest due to it being a potential pesticide target and an enzymatic tool for preparation of N-acetyl-β D-glucosamine. An individual insect contains multiple genes encoding chitinases, which vary in domain architectures, expression patterns, physiological roles and biochemical properties. Herein, Of ChtS, the glycoside hydrolase family 18 chiti- nase from the widespread lepidopteran pest Ostrinia furnacalis, was cloned, expressed in the yeast Pichia pastoris and biochemically characterized in an attempt to facilitate both pest control and biomaterial preparation. Complementary DNA sequence analysis indicated that Of CHT5 consisted of an open reading frame of 1 665-bp nucleotides. Phy- logenic analysis suggested Of Cht5 belongs to the Group I insect chitinases. Expression of Of Cht5 in Pichia pastoris resulted in highest specific activity after 120 h of induction with methanol. Through two steps of purification, consisting of ammonium sulfate pre- cipitation and metal chelating chromatography, about 7 mg of the recombinant Of Cht5 was purified to homogeneity from 1 L culture supernatant. Of Cht5 effectively converted colloidal chitin into chitobiose, but had relatively low activity toward a-chitin. When chi- tooligosaccharides [（GlcNAc）n, n = 3-6] were used as substrates, Of Cht5 was observed to possess the highest catalytic efficiency parameter toward （GlcNAc）4 and predominan- tely hydrolyzed the second glycosidic bond from the non-reducing end. Together with fl-N-acetyl-D-hexosaminidase OfHexl, Of Cht5 achieved its highest efficiency in chitin degradation that yielded N-acetyl-β D-glucosamine, a valuable pharmacological reagent and food supplement, within a molar concentration ratio of Of Cht5 versus Of Hexl in the range of 9 ： 1-15 ： 1. This work provides an alternative to existing preparation of chitinase for pesticides and other applications.

关键词： chitin chitinase glycoside hydrolase N-acetyl-β-D-glucosamine Ostriniafurnacalis pest control

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Gene regulatory networks driven by intrinsic noise with two-time scales： a stochastic averaging approach

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Frontiers of Mathematics in China 2014年第4期9卷 947-963页

作者： Fuke wu George YIN tianhai tian School of Mathematics and Statistics Huazhong University of Science and TechnologyWuhan 430074 China Department of Mathematics Wayne State University Detroit MI 48202 USA School of Mathematical Sciences Monash University Melbourne Vic 3800 Australia

This work focuses on gene regulatory networks driven by intrinsic noise with two-time scales. It uses a stochastic averaging approach for these systems to reduce complexity. Comparing with the traditional quasi-steady- state hypothesis （QSSH）, our approach uses stochastic averaging principle to treat the intrinsic noise coming from both the fast-changing variables and the slow-changing variables, which yields a more precise description of the underlying systems. To provide further insight, this paper also investigates a prototypical two-component activator-repressor genetic circuit model as an example. If all the protein productions were linear, these two methods would yield the same reduction result. However, if one of the protein productions is nonlinear, the stochastic averaging principle leads to a different reduction result from that of the traditional QSSH.

关键词： Two-time scales intrinsic noise intracellular reaction chemicalLangevin equation (CLE) stationary distribution

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Note on a Theorem of Bangert

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Acta Mathematica Sinica,English Series 2012年第1期28卷 121-132页

作者： tian Jun LI Wei Wei wu University of Minnesota Department of Mathematics

We generalize Bangert＇s non-hyperbolicity result for uniformly tamed almost complex structures on standard symplectic R^2n to asymptotically standard symplectic manifolds.

关键词： (Non-)complex hyperbolicity asymptotically standard rationally connected almost Kahler

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Flume experimental study on evolution of a mouth bar under interaction of floods and waves

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Water Science and Engineering 2019年第2期12卷 162-168页

作者： Li Yan Men-wu wu Ying Chen Yao wu tian-sheng wu Pearl River Hydraulic Research Institute Pearl River Water Resources CommissionGuangzhou 510611China Key Laboratory of the Pearl River Estuarine Dynamics and Associated Process Regulation Ministry of Water ResourcesGuangzhou 510610China College of Harbor Coastal and Offshore EngineeringHohai UniversityNanjing 210098China

Based on the characteristics of hydrodynamics and sediment transport in the bar area in the Modaomen Estuary,a flume experiment was performed to study the evolution of the longitudinal profile of the mouth *** mouth bar evolution was investigated under the impacts of floods with different return periods as well as flood-wave *** results showed that floods with different return periods had significant influences on the evolution of the river mouth *** on the inner slope of the mouth bar,the sediment was substantially active and *** inner slope and the bar crest tended to be remarkably *** erosion was intensified with the increase of the magnitude of ***,the bar crest moved seawards,while the elevation of the bar crest barely *** the flood-wave interaction,a remarkable amount of erosion on the inner and outer slopes of the mouth bar was also *** seaward displacement of the bar crest under the interaction of floods and waves was less than it was under only the impact of floods,while more deposition was found on the crest of the mouth bar in this case.

关键词： Modaomen Mouth bar Wave Flood Flume experiment Sediment transport

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真空热固结联合强夯处理工程废浆试验研究

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土木与环境工程学报（中英文） 2025年第1期47卷 18-26页

作者：吴建奇陶建伟符洪涛李校兵周晨阳陈腾江西理工大学土木与测绘工程学院江西省环境岩土与工程灾害控制重点实验室江西赣州341000 温州大学建筑工程学院浙江省软弱土地基与海涂围垦工程技术重点实验室浙江温州325035

为解决真空热固结过程中热量与真空负压在土体中衰减而导致土体加固效果不均匀的问题,利用强夯法能改善土体密实度的特性,将真空热固结法与强夯法联合应用于工程废浆的加固处理,通过4组室内模型试验研究不同夯击时机对土体加固效果的影... 详细信息

为解决真空热固结过程中热量与真空负压在土体中衰减而导致土体加固效果不均匀的问题,利用强夯法能改善土体密实度的特性,将真空热固结法与强夯法联合应用于工程废浆的加固处理,通过4组室内模型试验研究不同夯击时机对土体加固效果的影响。结果表明:沉降速率为每3 d沉降4 cm时为最佳夯击时机,土体表面沉降比其他试验组提高26.55%、11.72%和3.74%,对工程废泥浆的处理效果最佳,能有效解决真空热固结下深层土体加固效果差的问题,并提高土体的均匀性。通过微观结构分析发现,合适的夯击时机下,由于土颗粒之间的孔隙重分布,导致土体密实程度更高,十字板剪切强度随之增大。此外,内部孔隙重分布产生微裂缝形成的排水通道对排水有一定的促进作用,进一步提升了固结效果,在合适的夯击时机下,对土体的十字板剪切强度与固结度均有促进作用。

关键词：真空热固结夯击时机微观结构工程废浆固结度

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Nanocrystallization-locked Network of Poly(styrene-6-isobutylene-6-styrene)-g-Polytetrahydrofuran Block Graft Copolymer

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Chinese Journal of Polymer Science 2021年第7期39卷 874-886页

作者： Hang-tian Zhang Zhi-Tao Wei Fang Zhang tian Yang Yi-Xian wu State Key Laboratory of Chemical Resource Engineering Beijing Advanced Innovation Center for Soft Matter Sciences and EngineeringBeijing Laboratory of Biomedical MaterialsBeijing University of Chemical TechnologyBeijing 100029China

Poly(styrene-6-isobutylene-6-styrene)triblock copolymer(SIBS),a kind of thermoplastic elastomer with biocompatibility and biostability containing fully saturated soft segments,could be synthesized via living cationic copolymerization.A novel poly[(styrene-co-methylstyrene)-b-isobutylene-b-(styrene-co-methylstyrene)]-g-polytetrahydrofuran(M-SIBS-g-PTHF)block graft copolymer was prepared to increase the polarity and service temperature of SIBS by grafting polar PTHF segments onto SIBS.A series of the above block graft copolymers with average grafting numbers from 2 to 6 and molecular weights of PTHF branches ranging from 200 g·mol^(-1)to 4200 g·mol^(-1)were successfully synthesized via living cationic ring-opening polymerization of tetrahydrofuran(THF)coinitiated by *** introduction of PTHF branches led to an obvious microphase separation due to thermodynamic incompatibility among the three kinds of segments of polyisobutylene(PIB),polystyrene(PS)and ***,the microphase separation promotes the rearrangement of PTHF branches to form the nanocrystallization-locked physically cross-linked network after storage at room temperature for 2 months,leading to insolubility of the copolymers even in good *** melting temperature and enthalpy of PTHF nanocrystallization locked in hard domains of M-SIBS-g5-PTHF-1.1k block graft copolymer increased remarkably up to 153℃and 117.0 J·g^(-1)by 23℃and 11.6 J·g^-1(respectively after storage for long *** modulus(G′)is higher than loss modulus(G″)of M-SIBS-g-PTHF block graft copolymer at temperatures ranging from 100℃to 180℃,which is much higher than those of the SIBS triblock *** the best of our knowledge,this is the first example of high performance M-SIBS-g-PTHF block graft copolymers containing segments of PIB,PS and PTHF with nanocrystallization-locked architecture.

关键词： Poly(styrene-b-isobutylene-b-styrene) Polytetrahydrofuran Living cationic polymerization Block graft copolymers Nanocrystallization-locked network

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A numerical simulation study of CO2 injection for enhancing hydrocarbon recovery and sequestration in liquid-rich shales

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Petroleum Science 2018年第1期15卷 103-115页

作者： Sumeer Kalra Wei tian Xingru wu Warwick Energy Group 900 W Wilshire BlvdOklahoma City OK 73116 USA University of Oklahoma 100 E Boyd St. Sec 1210 NormanOK 73019-1003 USA

Less than 10% of oil is usually recovered from liquid-rich shales and this leaves much room for improvement, while water injection into shale formation is virtually impossible because of the extremely low permeability of the formation matrix. Injecting carbon dioxide（CO2） into oil shale formations can potentially improve oil recovery. Furthermore, the large surface area in organicrich shale could permanently store CO2 without jeopardizing the formation integrity. This work is a mechanism study of evaluating the effectiveness of CO2-enhanced oil shale recovery and shale formation CO2 sequestration capacity using numerical simulation. Petrophysical and fluid properties similar to the Bakken Formation are used to set up the base model for simulation. Result shows that the CO_2 injection could increase the oil recovery factor from7.4% to 53%. In addition, petrophysical characteristics such as in situ stress changes and presence of a natural fracture network in the shale formation are proven to have impacts on subsurface CO2 flow. A response surface modeling approach was applied to investigate the interaction between parameters and generate a proxy model for optimizing oil recovery and CO2 injectivity.

关键词： CO2 EOR Tight formations Experimentaldesign Response surface modeling Recovery of shaleliquid CO2 sequestration

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Decomposition Theorems and Conjugate Pair in D_K Spaces

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Acta Mathematica Sinica,English Series 2014年第9期30卷 1513-1525页

作者： Ji Zhen ZHOU Yu tian wu School of Sciences Anhui University of Science and Technology School of Mathematics and Information Sciences Zhaoqing University

Let K be a right-continuous and nondecreasing function. A function f analytic in the unit disk D belongs to the space OK if ∫D｜f＇（z）｜2K（1 - ｜z｜2）dA（z）〈 ∞. Decomposition theorems for OK spaces are established in this paper. As an application, we obtain a characterization of interpolation by functions in DK spaces. Furthermore, we characterize functions in DK spaces by conjugate pairs.

关键词： DK spaces decomposition theorem conjugate pair

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A Longitudinal Study of the Effects of Family Background Factors on Mathematics Achievements Using Quantile Regression

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Acta Mathematicae Applicatae Sinica 2008年第1期24卷 85-98页

作者： Xi-zhi wu Mao-zai tian Center for Applied Statistics School of Statistics Renmin University of China Beijing 100872 China School of Statistics Renmin University of China Beijing 100872 China

Quantile regression is gradually emerging as a powerful tool for estimating models of conditional quantile functions, and therefore research in this area has vastly increased in the past two decades. This paper, with the quantile regression technique, is the first comprehensive longitudinal study on mathematics participation data collected in Alberta, Canada. The major advantage of longitudinal study is its capability to separate the so-called cohort and age effects in the context of population studies. One aim of this paper is to study whether the family background factors alter performance on the mathematical achievement of the strongest students in the same way as that of weaker students based on the large longitudinal sample of 2000, 2001 and 2002 mathematics participation longitudinal data set. The interesting findings suggest that there may be differential family background factor effects at different points in the mathematical achievement conditional distribution.

关键词： Mathematical achievement family background factors quantile regression confidence intervals,longitudinal study

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Focus on Effects of Chinese Medicine on Improving Anxiety-Depression and Quality of Life of Patients with Primary Sjogren’s Syndrome

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Chinese Journal of Integrative Medicine 2020年第7期26卷 486-489页

作者： wu Guo-lin LI tian-yi Department of Traditional Chinese Medicine The First Affiliated HospitalCollege of MedicineZhejiang UniversityHangzhou(310003)China Basic Medical College Zhejiang University of Chinese MedicineHangzhou(310053)China

Primary Sjogren’s syndrome(pSS)is a chronic autoimmune disease with a long duration of illness,for which there is no *** often suffer from anxiety and depression due to various reasons,exhibiting a decline in their quality of *** medicine(CM)has certain advantages in the treatment of pSS,which not only helps relieve clinical symptoms and improve treatment outcomes,but also reduces anxiety and depression and improves the quality of ***,CM should be considered as early as possible given its effectiveness and synergistic effects in treating p SS.

关键词： primary Sjogren's syndrome Chinese medicine therapy quality of life anxiety and depression

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