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Cobalamin-dependent radical S-adenosyl-L-methionine protein functions with a partner to successively methylate tricyclic indole alkaloid for chuangxinmycin maturation and derivatization

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Science China Chemistry 2025年第1期 308-316页

作者： Sili wang Jiancheng huang Yanan du Wei huang Yufeng Xue Xiaokun Xu Guannan Zhong Yuanyuan Shi Bin Hong Xiaoying Bian Wen Liu State Key Laboratory of Chemical Biology Shanghai Institute of Organic Chemistry University of Chinese Academy of SciencesChinese Academy of Sciences State Key Laboratory of Microbial Technology Shandong University National Health Commission (NHC) Key Laboratory of Biotechnology for Microbial Drugs Institute of Medicinal BiotechnologyChinese Academy of Medical Science & Peking Union Medical College

Cobalamin(Cbl)-dependent radical S-adenosyl-L-methionine(SAM) proteins constitute the largest collection of the radical SAM superfamily that has hundreds of thousands of individual members. Many of these proteins are involved in the biosynthesis of pharmaceutically important natural products to catalyze chemically demanding reactions. In the biosynthetic pathway of chuangxinmycin(CXM), a unique indole alkaloid antibiotic with potent anti-infective activity, functionalization of the characteristic thiopyrano[4,3,2-cd]indole scaffold by regio-and stereoselective C3-methylation is believed to rely on a Cbl-dependent radical process, which, however, remained to be reconstituted biochemically. We here report the dissection of this enzymatic process, which requires the incorporation of Cxm8, a Cbl-dependent radical SAM protein, with Cxm9, a duF5825family protein that shares no homology to any proteins of known functions. Cxm8 and Cxm9 function together by forming an unexpected heterodimeric complex that selectively catalyzes C3-methylation of the tricyclic indole-S-hetero ring system in a successive manner, achieving CXM and a recently identified, C3-dimethylated congener. Detailed biochemical characterization,isotope labeling, structural simulation and bioinformatics analysis rationalized the catalysis of the Cxm8/Cxm9 complex and particularly the necessity of the duF5825 protein for C3-methylase activity. This is the first example that a Cbl-dependent protein acts with a partner to exhibit radical SAM activity.

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In situ preparation of hydrophobic CaCO_3 nanoparticles in a gas-liquid microdispersion process

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Particuology 2013年第4期11卷 421-427页

作者： le du Yujun wang Guangsheng Luo The State Key Laboratory of Chemical Engineering Department of Chemical EngineeringTsinghua University

This study presents a novel process of in situ surface modification ofCaCO3 nanoparticles using a multiple- orifice dispersion microreactor. CO2/Ca（OH）2 precipitation reaction was employed to prepare CaCO3 nanoparticles with sodium stearate surfactant. Synthesized CaCO3 products were characterized by ther- mogravimetric analysis （TGA）, infra-red （IR）, X-ray diffraction （XRD）, transmission electron microscopy （TEM） and Brunauer-Emmet-Teller analysis （BET）. The effect of various operation parameters on nanopar- ticles and the dosage of sodium stearate were determined. The results showed that the preparation process could be precisely controlled with efficient mass transfer process. The particles were highly hydropho- bic with a contact angle of 117~ and monodisperse with an average size of 30 nm. The adsorptions of sodium stearate and calcium ion on solid particles during the in situ surface modification process were investigated.

关键词： CaCO3 nanoparticlesIn situ surface modificationMicroreactorMass transfer

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Settlement Mode Analysis for An Immersed Tube Tunnel Considering A Nonuniform Foundation Under Tidal Load

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China Ocean Engineering 2022年第3期36卷 427-438页

作者： wang Yan-ning ZHOU huan-zhu wang le-chen Department of Civil and Environmental Engineering Shantou UniversityShantou 515063China State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou 221000China

Immersed tube tunnels are usually placed on soft soil layers in cross-sea tunnelling *** to the influence of stratum conditions and slope design,the longitudinal distribution of substratum layers is generally ***,the inhomogeneous deformation of the element-joint becomes the key factor in the failure of the immersed tube ***,a corresponding calculation method for joint deformation is needed to explore the deformation law of immersed tube *** constructing a three-section immersed tube tunnel analysis model(TTM),the relationship between the two types of deformation of the immersed tube tunnel structure in a longitudinal nonuniform soft soil foundation is described,and the deformation characteristics of the immersed structure under different boundaries are *** on the mechanical behaviour of the joint and foundation,according to the Timoshenko beam on the Vlasov two-parameter foundation(VTM),considering the tidal cyclic load during the operation and maintenance period,an example analysis is ***,the deformation characteristics and development trend of the immersed tube tunnel under the influence of different soil layers are *** obtained results have a certain guiding significance for the deformation calculation of immersed tube tunnels.

关键词： geotechnical engineering immersed tube tunnel theoretical analysis soft soil foundation element-soil interaction

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Solar flare prediction using highly stressed longitudinal magnetic field parameters

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Research in Astronomy and Astrophysics 2013年第3期13卷 351-358页

作者： Xin huang hua-ning wang Key Laboratory of Solar Activity National Astronomical Observatories Chinese Academy of Sciences

Three new longitudinal magnetic field parameters are extracted from SOHO/MDI magnetograms to characterize properties of the stressed magnetic field in active regions, and their flare productivities are calculated for 1055 active regions. We find that the proposed parameters can be used to distinguish flaring samples from non-flaring samples. Using the long-term accumulated MDI data, we build the solar flare prediction model by using a data mining method. Furthermore, the decision boundary, which is used to divide flaring from non-flaring samples, is determined by the decision tree algorithm. Finally, the performance of the prediction model is evaluated by 10-fold cross validation technology. We conclude that an efficient solar flare prediction model can be built by the proposed longitudinal magnetic field parameters with the data mining method.

关键词： Sun: magnetic fields -- Sun: flares -- methods: statistical

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Analytical model of vertical vibrations in piles for different tip boundary conditions:parametric study and applications

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第2期14卷 79-93页

作者： ning wang Kui-hua wang Wen-bing WU MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering Department of Civil EngineeringZhejiang University Engineering Faculty China University of Geoscience

In this paper,a model named fictitious soil pile was introduced to solve the boundary coupled problem at the pile *** the model,the soil column between pile tip and bedrock was treated as a fictitious pile,which has the same properties as the local *** tip of the fictitious soil pile was assumed to rest on a rigid rock and no tip movement was *** combination with the plane strain theory,the analytical solutions of vertical vibration response of piles in a frequency domain and the corresponding semi-analytical solutions in a time domain were obtained using the Laplace transforms and inverse Fourier transforms.A parametric study of pile response at the pile tip and head showed that the thickness and layering of the stratum between pile tip and bedrock have a significant influence on the complex ***,two applications of the analytical model were *** is to identify the defects of the pile shaft,in which the proposed model was proved to be accurate to identify the location as well as the length of pile *** application of the model is to identify the sediment thickness under the pile *** results showed that the sediment can lead to the decrease of the pile stiffness and increase of the damping,especially when the pile is under a low frequency load.

关键词： Soil-pile interaction Complex impedance Pile tip Vertical vibration Sediment

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Recent developments in microfluidic device-based preparation, functionalization, and manipulation of nano- and micro-materials

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Particuology 2019年第4期17卷 1-19页

作者： Guangsheng Luo le du Yujun wang Kai wang The State Key Lab of Chemical Engineering Department of Chemical Engineering Tsinghua University Beijing 100084 China The State Key Laboratory of Chemical Resource Engineering Beijing Key Laboratory of Membrane Science and Technology Beijing University of Chemical Technology Beijing 100029 China

Microfluidic systems provide a powerful platform for preparing,functionalizing,and manipulating nano-/*** this review,we summarize the characteristics of state-of-the-art microfluidic techniques and their application to processing novel nano-/micro-materials with tunable size,shape,morphology,composition,and properties.A variety of synthesis strategies based on novel microfiuidic devices are presented and compared,including their integration with real-time monitoring,external fields,and automatic feedback *** functional nano-/micro-materials with complex structures have been controllably prepared and post-processed to obtain high-quality *** for controlling and tuning physical and chemical properties are also examined in terms of the design and function of microfluidic *** provide an outlook on future developments in the processing of nano-/micro-materials by microfluidic technologies.

关键词： Microfluidics Microchemical systems Nanomaterials Micro-materials Scale-up

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pH-Responsive Polycarbonate Copolymer-based Nanoparticles for Targeted Anticancer Drug Delivery

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Chemical Research in Chinese Universities 2018年第6期34卷 1041-1050页

作者： LI Yunxia du Wenjuan FU Zhiguang wang huanhuan wang Jiexin le Yuan zhanG Jianjun WEN ning Department of Stomatology the General Hospital of Chinese PLA Beijing 100853 P. R. China Department of Oncology the General Hospital of Chinese PLA Beijing 100853 P. R. China College of Chemical Engineering Beijing University of Chemical Technology Beijing 100029 P. R. China

A smart polycarbonate（PCA） copolymer-based nanoparticle（NanoPCA） with pH-responsive, long-term stability, and tumor targeting ability was successfully developed by synthesizing and assembling a series of functional PCA-based copolymers including poly（2-amino-l,3-propanediol carbonate-co-L-lactide）[P（CA-co-LA）], poly（2- amino-1,3-propanediol carbonate-co-L-lactide）-g-methoxy-poly（ethylene glycol）[P（CA-co-LA）-g-MPEG], and poly（2-amino-1,3-propanediol carbonate-co-L-lactide）-g-poly（ethylene glycol）-cyclic（Arg-Gly-Asp-D-Phe-Lys） [P（CA-co-LA）-g-PEG-cRGD] for targeted anticancer drug delivery, pH-Responsive studies demonstrated that the loading doxorubicin（DOX） released faster from NanoPCA at acidic conditions due to protonation effects of P（CA-co-LA） copolymers. Furthermore, the in vitro and in vivo investigations demonstrate that the DOX-loaded NanoPCA exhibited significant tumor targeting ability, outstanding antitumor effect and excellent biological safety in the treatment of oral squamous cell carcinoma（OSCC）. Therefore, this work provides a promising drug delivery plat-form for cancer therapy and other applications.

关键词： Polycarbonate copolymer-based nanoparticle(NanoPCA) pH-Responsive Tumor targeting ability Oral squamous cell carcinoma(OSCC)

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黄河下游流域的文化界说——兼论华北平原在黄河文化中的历史地位

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河北学刊 2025年第1期45卷 98-110页

作者：王志民宋宁山东师范大学齐鲁文化研究院

黄河下游流域与文化的界定,是黄河文化研究中的一个重大问题。论者将黄淮海平原的广阔区域都作为黄河下游流域的传统看法是不恰当的。淮河作为一条大河,自有其独立的流域范围,“夺淮入海”时期,黄河夺占淮河支流和主河道,主要系人为因... 详细信息

黄河下游流域与文化的界定,是黄河文化研究中的一个重大问题。论者将黄淮海平原的广阔区域都作为黄河下游流域的传统看法是不恰当的。淮河作为一条大河,自有其独立的流域范围,“夺淮入海”时期,黄河夺占淮河支流和主河道,主要系人为因素改道和维持所致,且多为河道游移、水系混乱的“地上河”,并未形成自己的“集水区”;在文化上,淮河文化是长江文化的亚文化,在春秋战国时期是长江楚文化的重要组成部分。故无论从流域还是文化上看,淮河流域都不能作为黄河下游流域看待。泰沂山西延伏脉以北的华北平原,是黄河天然形成的入海之地;在秦汉以前,是中华文明起源、三代文明奠基的重要区域之一,是春秋战国时代的文化重心,是实现秦汉“大一统”的经学繁荣基地和思想库。该地区在中华文明起源、形成及中华民族共同体奠基的重要历史时期作出了突出贡献,是奠定黄河文化为中华民族“根”与“魂”的核心区之一。华北平原及其文化就是黄河下游的流域与文化。

关键词：黄河下游文化界说华北平原黄河文化

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Solar cycle distribution of major geomagnetic storms

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Research in Astronomy and Astrophysics 2013年第6期13卷 739-748页

作者： Gui-Ming le Zi-Yu Cai hua-ning wang Zhi-Qiang Yin Peng Li National Center for Space Weather China Meteorological Administration Key Laboratory of Solar Activity National Astronomical Observatories Chinese Academy of Sciences Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University) Ministry of Education The Second High School Attached to Beijing Normal University Nanjing University of Information Science & Technology

We examine the solar cycle distribution of major geomagnetic storms （Dst ≤ -100 nT）, including intense storms at the level of -200 nT〈 Dst ≤ -100 nT, great storms at -300 nT〈 Dst ≤-200 nT, and super storms at Dst ≤ -300 nT, which occurred during the period of 1957-2006, based on Dst indices and smoothed monthly sunspot numbers. Statistics show that the majority （82%） of the geomagnetic storms at the level of Dst≤ -100 nT that occurred in the study pe- riod were intense geomagnetic storms, with 12.4% ranked as great storms and 5.6% as super storms. It is interesting to note that about 27% of the geomagnetic storms that occurred at all three intensity levels appeared in the ascending phase of a solar cycle, and about 73% in the descending one. Statistics also show that 76.9% of the intense storms, 79.6% of the great storms and 90.9% of the super storms occurred during the two years before a solar cycle reached its peak, or in the three years after it. The correlation between the size of a solar cycle and the percentage of major storms that occurred, during the period from two years prior to maximum to three years af- ter it, is investigated. Finally, the properties of the multi-peak distribution for major geomagnetic storms in each solar cycle is investigated.

关键词： Sun sunspots -- Sun activity -- Sun solar-terrestrial relations

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The Browsing Pattern and Review Model of Online Consumers Based on Large Data Analysis

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Chinese Journal of Electronics 2015年第1期24卷 58-64页

作者： ning Lianju wang Haoyu FENG Xin du Junping School of Economics and Management Beijing University of Posts and Telecommunications Beijing Key Lab of Intelligent Telecommunication Software and Multimedia School of Computer ScienceBeijing University of Posts and Telecommunications

In the context of online shopping, commodity information and consumer reviews are main factors that will affect purchasing behavior. Started from the preference of commodity information browsing and the inherent property of online reviews, this paper focuses on the browsing data for statistical analysis and the interval distribution of consumer reviews based on the real data of360 buy which is the domestic large-scale B2 C commerce website in China. Researches find that commodity information browsing time distribution on Internet is fragment and can be depicted by the fat tail effect. It also demonstrated that user’s browsing patterns are related to the type of information and the displaying of the information,which means that the pieces of the picture and the length of the titles affecting the clicks rate. Reviews on the interval distribution can be depicted by the power-law function and there is a monotonically increasing relationship between power-exponent and the customers’ concerns with the corresponding commodity, the higher the exponent,the higher the degree of consumer attention. The finding obtained some basic rules of the browsing mode and review model, which is of important significance for future research.

关键词： Interval distribution Online consumer Browsing pattern Reviews model Trustworthiness.

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