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Biosynthesis of trialkyl-substituted aromatic polyketide NFAT-133 involves unusual P450 monooxygenase-mediating aromatization and a putative metallo-beta-lactamase fold hydrolase

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Synthetic and Systems Biotechnology 2023年第3期8卷 349-356页

作者： Ming Yang Wanlu Li lin zhou Xiao lin Wenyu Zhang Yaoyao Shen Hai Deng Hou-wen lin Yongjun zhou Research Center for Marine Drugs Department of PharmacyRen Ji HospitalSchool of MedicineShanghai Jiao Tong UniversityShanghai200127China Institute of Marine Drugs Guangxi Key Laboratory of Marine DrugsGuangxi University of Chinese MedicineNanning530200PR China Department of Chemistry University of AberdeenAberdeenAB243UEUK

The bacterial trialkyl-substituted aromatic polyketides are structurally featured with the unusual aromatic core in the middle of polyketide chain such as TM-123(1),veramycin A(2),NFAT-133(3)and benwamycin I(4),which were discovered from Streptomyces species and demonstrated with antidiabetic and immunosuppressant *** the biosynthetic pathway of 1-3 was reported as a type I polyketide synthase(PKS),the PKS assembly line was interpreted inconsistently,and it remains a mystery how the compound 3 was ***,the PKS assembly logic of 1-4 was revised by site-mutagenetic analysis of the PKS dehydratase *** on gene deletion and complementation,the putative P450 monooxygenase nftE1 and metallo-beta-lactamase(MBL)fold hydrolase nftF1 were verified as essential genes for the biosynthesis of *** absence of nftE1 led to abolishment of 1-4 and accumulation of new products(5-8).Structural elucidation reveals 5-8 as the non-aromatic analogs of 1,suggesting the NftE1-catalyzed aromatic core *** of nftF1 resulted in disappearance of 3 and 4 with the compounds 1 and 2 *** a rare MBL-fold hydrolase from type I PKSs,NftF1 potentially generates the compound 3 through two strategies:catalyze premature chain-offloading as a trans-acting thioesterase or hydrolyze the lactone-bond of compound 1 as an esterase.

关键词： Thioesterase Metallo hydrolase Metallo-beta-lactamase Aromatic polyketide Polyketide synthase P450 monooxygenase

Comparative study of HFACS and the 24Model accident causation models

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Petroleum Science 2017年第3期14卷 570-578页

作者： Gui Fu Jia-lin Cao lin zhou Yuan-Chi Xiang School of Resources and Safety Engineering China University of Mining and Technology (Beijing) Beijing 100083 China

A comparative study is conducted to compare the theory and application effect of two accident causation models, the human factors analysis and classification system（HFACS） and the accident causation ＂2-4＂ model（24 Model）, as well as to provide a reference for safety researchers and accident investigators to select an appropriate accident analysis method. The two models are compared in terms of their theoretical foundations, cause classifications, accident analysis processes, application ranges, and accident prevention strategies. A coal and gas outburst accident is then analyzed using both models, and the application results are compared. This study shows that both the 24 Model and HFACS have strong theoretical foundations, and they can each be applied in various domains. In addition, the cause classification in HFACS is more practical, and its accident analysis process is more convenient. On the other hand, the 24 Model includes external factors, which makes the cause analysis more systematic and comprehensive. Moreover, the 24 Model puts forward more corresponding measures to prevent accidents.

关键词： HFACS Accident causation "2-4" model Comparative study Unsafe acts External causes Coaland gas outburst accident

Controllable laning phase for oppositely driven disk systems

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Chinese Physics B 2019年第12期28卷 123-129页

作者： lin Liu Ke Li Xiao-lin zhou lin-Li He lin-Xi Zhang Department of Physics Zhejiang UniversityHangzhou 310027China Department of Physics Wenzhou UniversityWenzhou 325035China

A two-dimensional binary driven disk system embedded by impermeable tilted plates is investigated through nonequilibrium computer simulations. It is well known that a binary disk system in which two particle species are driven in opposite directions exhibits jammed, phase separated, disordered, and laning states. The presence of tilted plates can not only advance the formation of laning phase, but also effectively stabilize laning phase by suppressing massively drifting behavior perpendicular to the driving force. The lane width distribution can be controlled easily by the interplate distance. The collective behavior of driven particles in laning phase is guided by the funnel-shaped confinements constituted by the neighboring tilted plates. Our results provide the important clues for investigating the mechanism of laning formation in driven system.

关键词： driven system tilted plates laning phase drifting behavior

Air bubble breakup in shear water flows generated by a plug conduit:An experimental investigation

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Journal of Hydrodynamics 2023年第6期35卷 1077-1088页

作者： Han Wu Mao-lin zhou Wei-lin Xu Wang-ru Wei Jian-bo Li State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu610065China PowerChina Chengdu Engineering Corporation Limited Chengdu610072China

In the context of a sudden contraction plug conduit,the near-wall area experiences a significant shearing effect of water flow,however,the extent to which this shearing effect occurs in bubble-water flow and the related variation mechanisms of air bubble size and number remain *** study employs a model test method to investigate the diffusion process of bubble-water flow in a sudden contraction plug *** size and number of bubbles,as well as their distribution along the shearing section under varying initial air volume conditions,are studied in detail using a high-speed image acquisition *** experimental findings reveal a self-similar relationship between the number and size of bubbles and their cross-sectional distribution over *** bubble number and size vary in three stages,i.e.,quasi-suspension,shearing,and shearing completion *** direction perpendicular to the conduit exhibits peak values in bubble number distribution over the three stages,with peak value location varying with the near-wall *** time progresses,the peak value increases,and a larger initial air volume corresponds to a smaller distance of the peak value location from the *** size of air bubbles near the wall is consistent with the minimum diameter of air bubbles in shear flow and is hardly affected by the initial air *** results aid in comprehending the change law of two-phase water and air flow under a strong shearing effect in the plug conduit,and provide useful insights for hydraulic design in fluid engineering.

关键词： Air-water flows bubble properties air diffusion process plug conduits experimental study

Structure of BaGd_2(MoO_4)_4 Crystal

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Chinese Journal of Structural Chemistry 2007年第3期26卷 328-332页

作者： ZHAO Dan lin zhou-Bin WANG Guo-Fu State Key Laboratory of Structural Chemistry Fujian Institute of Research on theStructure of Matter The Chinese Academy of Sciences Fuzhou Fujian 350002 China Graduate School of the Chinese Academy of Sciences Beijing 100039 China

The title compound belongs to monoclinic, space group C2/c with a = 5.2694（1）, b = 12.6659（4）, c = 19.4108（2） A,β= 91.504（2）°, V = 1295.06（5） A^3, Z = 4 and Dc= 5.599 g/cm^3. The structure of BaGd2（MoO4）4 contains a MoO4 tetrahedron, a distorted GdO8 polyhedron, and Ba^2＋ ions in a tenfold coordination. The GdO8 polyhedra are linked together through edge-sharing to give a two-dimensional Gd layer. The MoO4 tetrahedra connected to the Gd atoms are capped up and down the Gd layer through common oxygen apices, thus-forming a new Gd-Mo layer. Finally, the Gd-Mo layers are held together through bridging BaO10 polyhedra to form a three-dimensional framework. Since the Ba-μ3-O bond has a large average distance of 2.888 A, this structural characteristic will result in a cleavage along the （001） plane.

关键词： Czochralski method BaGd2(MoO4)4 crystal

Transcriptome-based identification and expression analysis of the glutathione S-transferase(GST)family in tree peony reveals a likely role in anthocyanin transport

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Horticultural Plant Journal 2022年第6期8卷 787-802页

作者： Lulu Han Hongzhu Zou lin zhou Yan Wang Research Institute of Forestry Key Laboratory of Tree Breeding and Cultivation of National Forestry and Grassland AdministrationChinese Academy of ForestryBeijing 100091China

For red-flowered cultivars of tree peony(Paeonia suffruticosa),anthocyanin content is a critical factor determining the different petal *** S-transferases(GSTs)are ubiquitous and multifunctional conjugating proteins that may be responsible for the transport of anthocyanin pigments from the cytoplasm to *** underlying function of the GST family in tree peony,however,remains *** this study,we systematically isolated and identified a total of 54 putative full-length Ps GST genes through a combination of bioinformatics approaches from transcriptome *** phylogenetic analyses revealed extensive differentiation in their coding sequences and divided them into 10 of the 14 known classes of plant *** phylogenetic relationships,evolutionary characteristics,protein domain,and motif organization were clearly conserved among the different phylogenetic *** results of the RNA-seq and quantitative real-time polymerase chain reaction experiments exhibited extensive variation in gene expression profiles among different developmental stages and ***,the phylogenetic relationships,expression profiles,protein interactions,weighted gene co-expression network analysis,and correlation analysis results suggested that PsGSTF3(Unigene 0064200)is a candidate participant in anthocyanin transport and the promotion of pigment accumulation,exhibiting a strong positive correlation with anthocyanin content among different tissues(r=0.908**)and an increasing rate of anthocyanin content during the flower developmental process(r=0.961*).These results furthered our understanding of the transport and accumulation functions of the GST family as well as the enhancement of tree peony breeding through molecular biology techniques.

关键词： GST Paeonia suffruticosa Functional prediction Expression analysis Anthocyanin transportation

Zero Extension Problem for the Heat Equation

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Acta Mathematica Sinica,English Series 2022年第11期38卷 1981-1997页

作者： Ge Yang DU Qiang XU Shu lin zhou School of Mathematical Sciences Peking UniversityBeijing 100871P.R.China School of Mathematics and Statistics Lanzhou UniversityLanzhou 730000P.R.China LMAM School of Mathematical SciencesPeking UniversityBeijing 100871P.R.China

In this paper we present a necessary and sufficient condition to guarantee that the zeroextended function of the solution for the heat equation in a smaller cylinder is still the solution of the corresponding extension problem in a larger *** prove the results under the frameworks of classical solutions,strong solutions and weak ***,we generalize these results to uniformly parabolic equations of divergence form.

关键词： Heat equation zero extension initial-boundary value problem

A SPLIT-CHARACTERISTIC FINITE ELEMENT MODEL FOR 1-D UNSTEADY FLOWS

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Journal of Hydrodynamics 2007年第1期19卷 54-61页

作者： zhou Yi-lin TANG Hong-wu LIU Xiao-hua State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering College of Water Conservancy and Hydropower Engineering Hohai University Nanjing 210098 China.

An efficient and accurate solution algorithm was proposed for 1-D unsteady flow problems widely existing in hydraulic engineering. Based on the split-characteristic finite element method, the numerical model with the Saint-Venant equations of 1-D unsteady flows was established. The assembled f＇mite element equations were solved with the tri-diagonal matrix algorithm. In the semi-implicit and explicit scheme, the critical time step of the method was dependent on the space step and flow velocity, not on the wave celerity. The method was used to eliminate the restriction due to the wave celerity for the computational analysis of unsteady open-channel flows. The model was verified by the experimental data and theoretical solution and also applied to the simulation of the flow in practical river networks. It shows that the numerical method has high efficiency and accuracy and can be used to simulate 1-D steady flows, and unsteady flows with shock waves or flood waves. Compared with other numerical methods, the algorithm of this method is simpler with higher accuracy, less dissipation, higher computation efficiency and less computer storage.

关键词： split characteristic finite element method,tri-diagonal matrix algorithm 1-D unsteady flow flood wave,river networks

Quantum effects on thermal vibration of single-walled carbon nanotubes conveying fluid

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Acta Mechanica Solida Sinica 2017年第5期30卷 550-556页

作者： Ye-Wei Zhang lin zhou Bo Fang Tian-Zhi Yang Department of Astronautics Shenyang Aerospace University Shenyang 110136 PR China Department of Mechanics Tianjin University Tianjin 300072 PR China

In this paper, we investigate the microfluid induced vibration of a nanotube in thermal environment. Attention is focused on a special case that the law of energy equipartition is unreliable unless the quantum effect is taken into account. A nonlocal luler-Bernoulli beam model is used to model the transverse vibration of a single-walled nanotube （SWCNT）. Results reveal that the root of mean squared （RMS） amplitude of thermal vibration of the fluid-conveying SWCNT predicted from the quantum theory is lower than that predicted from the law of energy equipartition. The quantum effect on the thermal vibration of the fluid-conveying SWCNT is more significant for the cases of higher-order modes, lower flow velocity, lower temperature, and lower fluid density.

关键词： Quantum effectsLaw of energy equipartitionFluid-conveying SWCNTEuler beam theoryRoot of mean-squared amplitude