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First-order Derivative Spectrophotometry for the Determination of Vitamin C in Medicament

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Chemical Research in Chinese Universities 2008年第1期24卷 29-31页

作者： MENG Qing-fan teng Le-sheng JIANG Chao-jun An Jin-shuang LI Lei LU Jia-hui teng Li-rong College of Life Science Jilin University Changchun 130012 P. R. China

A novel method for the determination of vitamin C（Vc） is proposed in this article. After the reaction with Folin-Ciocalteau reagent at ambient temperature, Vc solution was scanned at 750--1100 nm, and its first-order derivative spectrum were obtained from the original spectrum. The values of derivative selected at 995 nm were used for determination. It was proved that Vc could quickly react with Folin-Ciocalteau reagent within 5 min and the product was quite stable for a long time. The conditions required for this method is not very complicated, its precision and accuracy are similar to those of the iodometric titration described in Chinese Pharmacopoeia, and the limit of detection is 0.312 μg/mL. The determination of the results of vitamin C tablet, pill, and injection demonstrates that this method has wide pharmaceutical applications.

关键词： First-order derivative spectroscopy Vitamin C determination Folin-Ciocalteau regent

Convenient and efficient access to tri-and tetra-substituted 4-fluoropyridines via a[3+2]/[2+1]cyclization reaction

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Chinese Chemical Letters 2022年第6期33卷 2982-2986页

作者： Xuejiao Tang Kun Liu Zeming Qu Junyan Zhan Rukui Zhu fan teng Lili Meng Yanmin Huang Chusheng Huang Yimiao He Qiang Zhu Guangxi Key Laboratory of Natural Polymer Chemistry and Physics College of Chemistry and MaterialsNanning Normal UniversityNanning 530001China Guangzhou Institutes of Biomedicine and Health Chinese Academy of SciencesGuangzhou 510530China Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle Nanchang Hangkong UniversityNanchang 330063China

A[3+2]/[2+1]cycloaddition reaction of gem–difluorocyclopropenes is presented,offering a mild and efficient approach to accessing tri-and tetra-substituted 4-fluoropyridines in moderate to good yields with excellent *** synthetic applications,including process-scale reactions,modification of bioactive molecules,derivatization reactions and synthesis of the analogue of the PKM2 modulator,are subsequently described.

关键词： 4-Fluoropyridine gem-Difluorocyclopropene [3+2]/[2+1]cyclization reaction DMSO as an oxidant Regioselectivity PKM2 modulator

Visible-light-initiated tandem synthesis of difluoromethylated oxindoles in 2-MeTHF under additive-,metal catalyst-,external photosensitizer-free and mild conditions

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Chinese Chemical Letters 2021年第6期32卷 1907-1910页

作者： Qing-Wen Gui fan teng Zhou-Chao Li Zhi-Yuan Xiong Xue-Feng Jin Ying-Wu Lin Zhong Cao Wei-Min He College of Chemistry and Materials Science Hunan Agricultural UniversityChangsha 410128China School of Chemistry and Chemical Engineering University of South ChinaHengyang 421001China Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation Changsha University of Science and TechnologyChangsha 410114China

An efficient and eco-friendly protocol for synthesizing difluoromethylated oxindoles through a visiblelight induced one-pot tandem reaction of N-arylacrylamides,difluoroacetic acid and Ph I(OAc)_(2)was *** reaction proceeded in the absence of any additive,base,metal-catalyst and external photosensitizer,using cheap and easily available CHF_(2)CO_(2)H as the difluoromethylation reagent and bulk biomass-derived 2-Me THF as the sole solvent.26 Examples of N-arylacrylamide substrates were investigated,and all of them successfully underwent difluoromethylation to deliver the target products in good to excellent yields.

关键词： Green chemistry Visible light External photosensitizer-free Tandem reaction 2-MeTHF

Ultrasound-assisted tandem synthesis of tri-and tetra-substituted pyrrole-2-carbonitriles from alkenes,TMSCN and N,N-disubstituted formamides

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Chinese Chemical Letters 2020年第12期31卷 3241-3244页

作者： Qing-Wen Gui fan teng Sheng-Neng Ying Yang Liu Tao Guo Jian-Xin Tang Jin-Yang Chen Zhong Cao Wei-Min He College of Chemistry and Materials Science Hunan Agricultural UniversityChangsha 410128China School of Life Scienices and Chenistry Hunan University of Technologyzhuzhou 412007China Hunan Provincial Key Laboratory of Materials Protection for Flectric Power and Tramnsportation Changsha Univerity of Sciene and TechnologyChangsha 410114China

An energy-saving and eco-friendly method for the efficient construction of various tri-and tetrasubstituted pyrrolecarbonitriles through ultrasound-assisted multicomponent tandem reaction of readily available alkenes,TMSCN and N,N-disubstituted formamides within 40 min under metal-,solvent-free and mild conditions was *** dual role of iodine(catalyst and oxidant)notably simplified the reaction conditions and reduced the chemical waste generated.

关键词： Green chemistry Solvent-free Tandem reaction Dual role Ultrasound

Circulating tumor cells shielded with extracellular vesicle-derived CD45 evade T cell attack to enable metastasis

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Signal Transduction and Targeted Therapy 2024年第5期9卷 2114-2131页

作者： Chuan Yang Xueping Wang Kenneth K.W.To Caimei Cui Min Luo Shaocong Wu Lamei Huang Kai Fu Can Pan Zeyu Liu teng fan Caibo Yang fang Wang Liwu Fu State Key Laboratory of Oncology in South China Guangdong Provincial Clinical Research Center for CancerSun Yat-sen University Cancer CenterGuangzhou 510060P.R.China School of Pharmacy Faculty of MedicineThe Chinese University of Hong KongHong KongChina LABVIV Technology(Shenzhen)Co. LtdShenzhen 518057China

Circulating tumor cells(CTCs)are precursors of distant metastasis in a subset of cancer patients.A better understanding of CTCs heterogeneity and how these CTCs survive during hematogenous dissemination could lay the foundation for therapeutic prevention of cancer *** remains elusive how CTCs evade immune surveillance and elimination by immune *** this study,we unequivocally identified a subpopulation of CTCs shielded with extracellular vesicle(EVs)-derived CD45(termed as CD45^(+)CTCs)that resisted T cell attack.A higher percentage of CD45^(+)CTCs was found to be closely correlated with higher incidence of metastasis and worse prognosis in cancer ***,CD45^(+)tumor cells orchestrated an immunosuppressive milieu and CD45^(+)CTCs exhibited remarkably stronger metastatic potential than CD45−CTCs in ***,CD45 expressing on tumor surfaces was shown to form intercellular CD45-CD45 homophilic interactions with CD45 on T cells,thereby preventing CD45 exclusion from TCR-pMHC synapse and leading to diminished TCR signaling transduction and suppressed immune ***,these results pointed to an underappreciated capability of EVs-derived CD45-dressed CTCs in immune evasion and metastasis,providing a rationale for targeting EVs-derived CD45 internalization by CTCs to prevent cancer metastasis.

关键词： CD45 metastasis prevention

Simple nucleophile/H_(2)O promoted defluorinative ring-opening of gem-difluorocyclopropenes

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Green Synthesis and Catalysis 2024年第1期5卷 14-19页

作者： Yimiao He Jingwen Yuan Wen-Xin Lv Peng Liu fan teng Qijin Mo Zihua Wu Chusheng Huang Qianwen Liu Honggen Wang Guangxi Key Laboratory of Natural Polymer Chemistry and Physics College of Chemistry and MaterialsNanning Normal UniversityNanning530001China School of Pharmaceutical Sciences Sun Yat-sen UniversityGuangzhou510006China School of Chemistry Chemical Engineeringand BiotechnologyNanyang Technological University117543Singapore Guangzhou Institutes of Biomedicine and Health Chinese Academy of SciencesGuangzhou510530China Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle Nanchang Hangkong UniversityNanchang330063China

A novel defluorinative ring-opening of gem-difluorocyclopropenes is presented,providing a concise and efficient method for accessing 2-fluoropropenals and 2-fluorobuta-1,3-dienes in moderate to good yields with excellent regio-and *** reaction is performed under mild conditions with no need of using an excess amount of nucleophilic *** plays a crucial role in this transformation.

关键词： gem-difluorocyclopropene Ring-opening defluorination 2-Fluoropropenal 2-Fluorobuta-1,3-diene Water

Spin relaxation induced by interfacial effects in GaN/Al_(0.25) Ga_(0.75) N heterostructures

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Fundamental Research 2021年第6期1卷 656-660页

作者： Shixiong Zhang Ning Tang Xiaoyue Zhang Xingchen Liu Lei Fu Yunfan Zhang teng fan Zhenhao Sun Fentao Wang Weikun Ge Bo Shen State Key Laboratory of Artificial Microstructure and Mesoscopic Physics School of PhysicsPeking UniversityBeijing 100871China Frontiers Science Center for Nano-optoelectronics and Collaboration Innovation Center of Quantum Matter Peking UniversityBeijing 100871China Peking University Yangtze Delta Institute of Optoelectronics Nantong 226010China

Spin relaxation induced by the interfacial effects in GaN/Al_(0.25) Ga_(0.75) N heterostructures was carefully investigated using a photon-energy-dependent time-resolved Kerr rotation *** existence of the interfacial localized states with potential fluctuations at the GaN/AlGaN heterointerface leads to photoluminescence peaks showing blue and S-shaped shifts owing to the excitation power and temperature,*** electrons in the localized states show a spin relaxation time longer than 1 ns because of the suppression of the D’yakonov-Perel’(DP)scattering,while the spin relaxation time of free electrons was approximately only 10 ps because of the giant Rashba spin-orbit coupling induced by the interfacial polarization field under the framework of the DP scattering ***,it is found that the high electron mobility at the heterointerface results in a long spin diffusion length of 300 nm at high temperatures,which is promising for the development of GaN-based spintronic devices.

关键词： GaN/AlGaN heterointerface Two-dimensional electron gas Interfacial localized state Spin dynamics Polarization field

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未偿率模型:保险公司风险度量的新方法

统计研究 2007年第4期24卷 47-50页

作者：孟生旺滕帆中国人民大学应用统计科学研究中心浙江大学宁波理工学院

本文在借鉴保险公司常用的风险度量方法,如Value at Risk、破产概率以及保单持有人预期亏空等方法的基础上,利用条件尾部期望从保单持有人和保险监管人的角度构造了一个新的风险度量模型—未偿率模型,并对该模型的性质进行了初步讨论。

关键词：未偿率模型风险度量条件尾部期望

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低轨天基信息定向分发区域分割编码控制方法

宇航学报 2020年第5期41卷 592-598页

作者：李献斌王建范广腾军事科学院国防科技创新研究院北京100071

为提高低轨指向性信息分发链路的频谱利用效率,从天基分发平台与地面用户的相对位置关系入手,建立了分发指向、编码增益与信道传输容量的量化关系。在此基础上,提出一种低轨天基信息定向分发区域分割编码控制方法,该方法针对不同信息分... 详细信息

为提高低轨指向性信息分发链路的频谱利用效率,从天基分发平台与地面用户的相对位置关系入手,建立了分发指向、编码增益与信道传输容量的量化关系。在此基础上,提出一种低轨天基信息定向分发区域分割编码控制方法,该方法针对不同信息分发区域,采用最小均方误差(MMSE)作为区域分割准则选择编码方式,既提升了信道传输效率也便于工程实现。最后,本文通过仿真分析了方法的效能和性能影响因素,并与现有自适应编码方法进行了对比,验证了本方法的有效性和可靠性。

关键词：低轨天基信息定向分发编码控制