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Dynamics and biological relevance of epigenetic N^(6)-methyladenine DNA modification in eukaryotic cells

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Chinese Chemical Letters 2022年第5期33卷 2253-2258页

作者： Yuwei sheng Meijuan Zhou Changjun You Xiaoxia dai State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical EngineeringMolecular Science and Biomedicine LaboratoryHunan Provincial Key Laboratory of Biomacromolecular Chemical BiologyHunan UniversityChangsha 410082China

DNA methylation represents a major type of DNA modifications that play key roles in diverse biological *** the recent development of highly selective and sensitive bioanalytical techniques,N^(6)-methyladenine(6mA)has been characterized as an important internal DNA modification dynamically occurring in multiple eukaryotes including *** evidence has indicated that 6mA may act as a novel epigenetic modification involved in regulation of development,stress response and diseases such as cancer and neurodegenerative *** review herein the recent advances in the detection and functional studies of 6mA modification,with special emphasis on its biological consequences and human health relevance as well as its dynamic regulation by various types of methyltransferases,demethylases and 6mA-binding *** can be envisaged that further chemical and biological studies of 6mA modification will lead to a better understanding about its potentially important roles in normal and pathological biological processes.

关键词： DNA modification N^(6)-Methyladenine Epigenetic mark Methyltransferase Demethylase

Influence of dynamic tissue properties on temperature elevation and lesions during HIFU scanning therapy:Numerical simulation

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Chinese Physics B 2020年第3期29卷 277-284页

作者： Xiao Zou Hu Dong sheng-You qian School of Physics and Electronics Hunan Normal UniversityChangsha 410081China

When large tumors are treated,ablation of the entire volume of tumors requires multiple treatment spots formed by high intensity-focused ultrasound(HIFU)scanning *** heating effect of HIFU on biological tissue is mainly reflected in temperature elevation and tissue *** property parameters vary with temperature and,in turn,the distribution of temperature as well as the heating effects change *** this study,an HIFU scanning therapy model considering dynamic tissue properties is *** acoustic fields and temperature fields are solved combining the Helmholtz wave equation with Pennes bio-heat transfer equation based on the finite element method(FEM)to investigate the effects of various tissue properties(i.e.,the attenuation coefficient,acoustic velocity,thermal conductivity,specific heat capacity,density,and blood perfusion rate)on heating *** of the temperature distribution and thermal lesions under static and dynamic properties are made based on the data of tissue property parameters varying with *** results show that the dynamic changes of thermal conductivity,specific heat capacity,and acoustic velocity may account for the decrease of temperature elevation in HIFU treatment,while the dynamic changes of attenuation coefficient,density,and blood perfusion rate aggravate the increase of temperature on treatment *** with other properties,the dynamic change of attenuation coefficient has a greater impact on tissue temperature *** HIFU scanning therapy,the temperature elevation and tissue lesions of the first treatment spot are smaller than those of the subsequent treatment spots,but the temperature on the last treatment spot drops faster during the cooling *** ellipsoidal tissue lesion is not symmetrical;specifically,the part facing toward the previous treatment spot tends to be *** the condition of the same doses,the temperature elevation and the size of tissue l

关键词： high intensity-focused ultrasound(HIFU) temperature elevation tissue lesions dynamic tissue properties

Coverage Probability Analysis for Full-Duplex Relay Aided Device-to-Device Communications Networks

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China Communications 2016年第11期13卷 60-67页

作者： Bin Zhong Jiajia Zhang qian Zeng Xiaoming dai School of Information and Electrical Engineering Hunan University of Science and Technology Beijing Engineering and Technology Research Center for Convergence Networks and Ubiquitous Services University of Science and Technology Beijing Business School Xiangtan University

The coverage probability of both the cellular users and the Device-to-Device(D2D) users are analyzed. We assume that the cellular users are able to communication with the Base Station(BS) either by relying on the assistance of Full-Duplex(FD) mode relays or via direct user-to-BS links with high-enough Signal-to-Interference-plus-Noise-Ratio(SINR). Note that the FD-mode devices are capable of simultaneously operating in two modes,i.e. the D2D mode and the cooperative relay mode,with the sum power consumption at these devices kept constant. The closedform expressions for coverage probability of both tier users are derived. After that,numerical analyses are provided,showing that the coverage probability of the both the cellular and the D2D users can be substantially influenced by a variety of parameters,including the power allocation factor of the relays,the density of users,and the self-interference imposed on the FD mode relays,etc. Furthermore,in the D2D enabled networks,it is shown that the FD relay aided transmission is beneficial to enhancing the coverage probability of the cellular users if the target SINR is lower than 5 d B.

关键词： cooperative communication coverage probability Full-duplex device-to-device

One-sided empirical Bayes test for location parameter in Gamma distribution

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Applied Mathematics(A Journal of Chinese Universities) 2018年第3期33卷 287-297页

作者： YUAN Min ZHANG qian WEI Lai-sheng School of Public Health Administration Anhui Medical University Department of Statistics and Finance University of Science and Technology of China

In this paper, we devote to constructing the one-sided empirical Bayes(EB) test for the location parameter in the Gamma distribution by nonparametric method. Under some mild conditions, we prove that the EB test is asymptotically optimal with the rate of the order O(n^(-δs/(2s+1))), where 1/2 ≤ δ 1 is a given natural number. An example is also given to illustrate that the conditions of the main theorems are easily satisfied.

关键词： three parameter Gamma distribution location parameter one-sided empirical Bayes test asymptotically optimality convergence rate

A multi-enzymatic cascade reaction for the synthesis of bioactive C-oligosaccharides

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Chinese Chemical Letters 2024年第6期35卷 451-455页

作者： Kebo Xie qian Zhang Fei Ye Jungui dai State Key Laboratory of Bioactive Substance and Function of Natural Medicines CAMS Key Laboratory of Enzyme and Biocatalysis of Natural Drugs and NHC Key Laboratory of Biosynthesis of Natural ProductsInstitute of Materia MedicaChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100050China

C-Oligosaccharides are rare in nature and possess diverse ***,their chemical synthesis faces many *** this work,enzymatic introduction of C-linked sugar chains to target aglycones was successfully achieved by multi-enzymatic cascade reactions.A C-glycosyltransferase from Aloe barbadensis was employed to introduce the first C-linked glucose and then a cyclomaltodextrin glucanotransferase from Bacillus licheniformis was used to extend the sugar chain.A total of twenty C-oligosaccharides with 2-6 sugars were synthesized from scale-up reactions and exhibited good water solubility and sodium-dependent glucose transporter 2(SGLT2)inhibitory ***,a glucoamylase was used to control the length of the sugar chain and the C-maltosides were efficiently *** findings not only expanded the structural diversity of C-oligosaccharides,but also provided a strategy for the modification of C-glycoside drugs to improve the druggability.

关键词： C-Oligosaccharides C-Glycosyltransferase Cyclomaltodextrin glucanotransferase Glucoamylase Enzymatic synthesis SGLT2 inhibitory activity

Investigations into the thermal non-equilibrium of W UMa-type contact binaries

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Research in Astronomy and Astrophysics 2018年第5期18卷 83-92页

作者： Xiao Xiong Liang Liu sheng-Bang qian Yunnan Observatories Chinese Academy of Sciences Kunming 650011 China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences Beijing 100101 China University of Chinese Academy of Sciences Beijing 100049 China

Traditionally, some physical details（e.g., magnetic braking, energy transfer, angular momentum loss, etc.） have to be taken into consideration during investigations into the evolution of contact binaries. However, the real evolutionary processes which usually contain several of these physical mechanisms are very complicated as a result of strong interaction between components. To avoid dealing with these factors, a linear relationship is applied to the temperatures of components. It is found that the higher the mass ratio（M2/M1） of a contact system, the weaker the deviation from thermal *** this basis, a variation trend of fill-out factor（f） changing with mass ratio can be inferred, which is consistent with observations. Moreover, if we stick to this point of view, it should be natural that the number of semi-detached binaries in the predicted broken-contact phase of relaxation oscillations is less than the number in the contact phase.

关键词： stars binaries close - stars binaries eclipsing - stars evolution

Effects of RRA Treatments on Microstructures and Properties of a New High-strength Aluminum-Lithium Alloy-2A97

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Chinese Journal of Aeronautics 2007年第2期20卷 187-192页

作者： YUAN Zhi-shan LU Zheng XIE You-hua dai sheng-long LIU Chang-sheng School of Materials ＆ Metallurgy Northeastern University Shenyang 110004 China Beijing Institute of Aeronautical Materials Beijing 100095 China

A new high strength 2A97 Al-Cu-Li-X alloy was subjected to triple-aging of retrogression and re-aging treatments （RRA）. Transmission electron microscopy （TEM）, differential scanning calorimetry （DSC）, and tensile tests were used to investigate the effects of RRA treatment on the microstructures and properties. DSC test reveals the reversion temperature range of the strengthening δ＇（Al3Li） phase. The results show that the microstructure consists of δ＇（Al3Li） phase, T1 （Al2CuLi） phase and θ″/θ′（Al2Cu） phase for 2A97 alloy treated by a triple-aging of a retrogression and re-aging treatment in the following order：（1） at 165℃×30 min, （2） at 220 ℃ or 240℃ × 15 min, （3） at 165℃×24 h. The plastic deformation, incorporated into the treatment after secondary high temperature aging, promotes the T1 precipitation during final re-aging. The tensile properties of the alloy treated by the retrogression and re-aging treatment reach the peak level of alloy single-aged at 165℃ in T6 temper.

关键词： 2A97 Al-Cu-Li-X alloy RRA treatments triple aging microstructure reversion

A new rotation method for constructing orthogonal Latin hypercube designs

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Science China Mathematics 2023年第4期66卷 839-854页

作者： Chong sheng Jinyu Yang Min-qian Liu National Key Laboratory for Complex Systems Simulation Beijing 100101China School of Statistics and Data Science LPMC&KLMDASRNankai UniversityTianjin 300071China

Latin hypercube designs(LHDs)are very popular in designing computer *** addition,orthogonality is a desirable property for LHDs,as it allows the estimates of the main effects in linear models to be uncorrelated with each other,and is a stepping stone to the space-filling property for fitting Gaussian process *** the available methods for constructing orthogonal Latin hypercube designs(OLHDs),the rotation method is particularly attractive due to its theoretical elegance as well as its contribution to spacefilling properties in low-dimensional *** paper proposes a new rotation method for constructing OLHDs and nearly OLHDs with flexible run sizes that cannot be obtained by existing ***,the resulting OLHDs are improved in terms of the maximin distance criterion and the alias matrices and a new kind of orthogonal designs are *** properties as well as construction algorithms are provided.

关键词： computer experiment factorial design Latin hypercube design maximin distance orthogonality

Many—Body Contributions to Cohesive Energy of Highly Compressed Solid ^4He^＊

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Chinese Physics Letters 2003年第5期20卷 706-708页

作者： TIANChun-Ling LIUFu-sheng CAILing-Cang JINGFu-qian InstituteofPhysics SouthwestJiaotongUniversityChengdu610031 LaboratoryofShockWaveandDetonationPhysicsResearch ChineseAcademyofEngineeringPhysicsMianyang621900

A many-body expansion of cohesive energy of solid 4He is made up to five-body term, and short-range two-, three-, four- and five-body contributions have been computed by using the Hartree-Fock self-consistent-field technique and the same atomic basis set (6311G). At high densities the Hartree-Fock part of two- and four-body contributions are repulsive, whereas the three- and five-body ones are attractive. The four-body term increases as much as 15% repulsion of two-body term, and at the same time the five-body term reduces 4% of two-body repulsion at 2.5 cm3/mol. The four- and five-body terms are found to be important to describe short-range inter-atomic interaction correctly and to compute the cohesive energy accurately in a wide compression range from 2.5 to 7.5 cm3/mol.

关键词： ~4He 氦离子粘着能量高压缩固体相互作用数值计算