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Recent advances using cyclopropanols and cyclobutanols in ring-openingasymmetric synthesis

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Green Synthesis and Catalysis 2022年第3期3卷 219-226页

作者： Hong Yan Gregory S.Smith Fen-er chen Institute of Pharmaceutical Science and Technology College of ChemistryFuzhou UniversityFuzhou 350108China Engineering Center of Catalysis and Synthesis for Chiral Molecules Department of ChemistryFudan UniversityShanghai 200433China Shanghai Engineering Research Center of Industrial Asymmetric Catalysis of Chiral Drugs Fudan UniversityShanghai 200433China Department of Chemistry University of Cape TownRondeboschCape Town 7700South Africa

Due to high ring strain energies,cyclopropanols and cyclobutanols have a strong tendency of breaking theendocyclic C–C bonds to participate in versatile organic *** an inherent three-dimensionalstructure,cyclopropanols and cyclobutanols have the advantage of synthesizing linear or cyclic molecules withstereogenic centers via ring-opening asymmetric *** are three strategies for the ring-opening ofcyclopropanols and cyclobutanols usually involved in asymmetric synthesis:1)β-carbon elimination of metalalkoxide;2)radical ring-opening;3)ring-opening via semipinacol *** present review has high-lighted the progress developed in the last five years.

关键词： Cyclopropanol Cyclobutanol Ring-opening C–C bond cleavage Asymmetric synthesis

Asymmetric catalytic hydrogenation of imines and enamines in natural product synthesis

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Green Synthesis and Catalysis 2020年第1期1卷 26-41页

作者： Pei Tang Huijing Wang Wen Zhang Fen-er chen Sichuan Research Center for Drug Precision Industrial Technology West China School of PharmacySichuan UniversityChengdu 610041China Engineering Center of Catalysis and Synthesis for Chiral Molecules Department of ChemistryFudan UniversityShanghai 200433China Shanghai Engineering Center of Industrial Asymmetric Catalysis for Chiral Drugs Shanghai 200433China

Asymmetric catalytic hydrogenations of imines and enamines with chiral transition-metal complexes bearing chiral ligands are among the most green and powerful approaches for the elaboration of chiral amine structures in organic *** review focuses on recent applications of asymmetric hydrogenations of imine and enamine substrates in the total syntheses of natural *** applications include diverse processes involving asymmetric transfer hydrogenation(ATH)and asymmetric hydrogenation(AH)to form key chiral amine motifs in natural products with good efficiency and high-level enantiocontrol.

关键词： Asymmetric catalytic hydrogenation Imine substrates Enamine substrates Natural product synthesis Enantioselectivity

Niobium and phosphorus behavior during melting-separation process of pre-reduced niobium ore concentrate

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Journal of Iron and Steel Research International 2017年第7期24卷 691-696页

作者： Yu-bao Liu Zhi-hong Zhang er-xiong Zhao Xian-heng Zhang Xiao-qing Wang Guo-hua chen Inner Mongolia Niobium Metallurgical Engineering Laboratory Baotou Research Institute of Rare Earths State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization

The pre-reduced Bayan Obo ferroniobium（FeNb）ore concentrate block was taken as raw materials for studying the physical properties of niobium-enriched slag and changes in niobium recovery *** addition,the dephosphorization rate of the slag under different melting-separation conditions was investigated using the melting-separation *** research results demonstrate that（i）the niobium recovery rate and dephosphorization rate of the slag decrease with the increase in melting-separation temperature;（ii）the niobium recovery rate of the slag initially increases and then decreases with increase in basicity and time;and（iii）the dephosphorization rate of the slag increases with the increase in basicity and *** the test was performed under the conditions of basicity of 0.6-0.7,time of 7-10min,and temperature of 1400-1450°C,the niobium recovery rate and dephosphorization rate are over 96%and 95%,*** scanning electron microscopy,it is observed that niobium mainly exists in the form of calcium and titanium silicate within the slag phase,with uneven distribution.

关键词： Melting separation Pre-reduced niobium ore concentrate Niobium-enriched slag Iron Dephosphorization rate Niobium recovery rate

The Shackling Effect in Cyclic Azobenzene Liquid Crystal

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Chinese Journal of Polymer Science 2022年第6期40卷 584-592页

作者： Yang Xiao Chong He Zi-Fan Yang er-Qiang chen Huan-Jun Lu Xiao-Hong Li Ying-Feng Tu State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials College of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China Beijing National Laboratory for Molecular Sciences Key Laboratory of Polymer Chemistry and Physics of Ministry of EducationCenter for Soft Matter Science and EngineeringCollege of ChemistryPeking UniversityBeijing 100871China Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application School of Physical Science and TechnologySuzhou University of Science and TechnologySuzhou 215009China

We demonstrate here a novel method for the design of liquid crystals(LCs)via the cyclization of mesogens by flexible *** two azobenzene-4,4′-dicarboxylate derivatives,the cyclic dimer,cyclic bis(tetraethylene glycol azobenzene-4,4′-dicarboxylate)(CBTAD),shows LC properties with smectic A phase,while its linear counterpart,bis(2-(2′-hydroxyethyloxy))ethyl azobenzene-4,4′-dicarboxylate(BHAD),has no LC *** difference is ascribed to the shackling effect from the cyclic topology,which leads to the much smaller entropy change during phase transitions and increases the isotropic temperature greatly for *** addition,the trans-to-cis isomerization of azobenzene groups under UVlight is also limited in *** the reversible isomerization of azobenzene groups,CBTAD showed interesting isothermal phase transition behaviors,where the LC phase disappeared upon photoirradiation of 365 nm UV-light,and recovered when the UV-light was *** with the smectic LC nature,a novel UV-light tuned visible light regulator was designed,by simply placing CBTAD in two glass *** scattered phase of smectic LC was utilized as the“OFF”state for light passage,while the UV-light induced isotropic phase was utilized as the“ON”*** shackling effect outlined here should be applicable for the design of cyclic LC oligomers/polymers with special properties.

关键词： Azobenzene Cyclic Liquid crystals Isothermal phase transition

Recent advances in remote C(sp^(3))-H functionalization via chelating group-assisted metal-catalyzed chain-walking reaction

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Chinese Chemical Letters 2024年第11期35卷 99-110页

作者： Jian Han Li-Li Zeng Qin-Yu Fei Yan-Xiang Ge Rong-Hui Huang Fen-er chen School of Pharmacy Changzhou UniversityChangzhou 213164China Engineering Center of Catalysis and Synthesis for Chiral Molecules Department of ChemistryFudan UniversityShanghai 200433China Shenzhen Research Institute of Nanjing University Shenzhen 518057China

Aliphatic C(sp^(3))-H moieties are ubiquitous in numerous organic *** functionalization of inert C(sp^(3))-H bonds is a powerful and straightforward approach for the efficient construction of diverse carbon-carbon or carbon-heteroatom *** group directed metal-catalyzed remote functionalization of readily available alkenes has emerged as an appealing strategy for rapidly accessing various value-added aliphatic *** the aid of directing groups,variousα-,β-andγ-functionalized alkanes could be synthesized smoothly with excellent *** preferred formation of a stable five-or six-membered metallacycle intermediate terminates the chain-walking at a specific methylene site,which serves as the driving force for excellent site-selective migratory *** review herein is aimed at summarizing the recent progress on the metal-catalyzed regiodivergent functionalization of unactivated alkenes by merging alkene isomerization and cross-coupling with the assistance of directing *** but not least,the current situations and future directions in this field are highlighted and discussed.

关键词： Chelating group Chain-walking Regiodivergent Unactivated alkenes C(sp^(3))-H functionalization Transition-metal catalysis

XPD Lys751Gln polymorphism and esophageal cancer risk: A meta-analysis involving 2288 cases and 4096 controls

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World Journal of Gastroenterology 2011年第18期17卷 2343-2348页

作者： Ling Yuan Dan Cui er-Jiang Zhao chen-Zhi Jia Li-Dong Wang Wei-Quan Lu Department of Gastroenterology The First Affiliated Hospital Zhengzhou University Zhengzhou 450052 HenanProvince China Department of Radiotherapy Henan Tumor Hospital and Institute Zhengzhou 450003 Henan Province China Department of Epidemiology HenanTumor Institute Zhengzhou 450003 Henan Province China Department of Epidemiology andBiostatistics College of Public Health Zhengzhou UniversityZhengzhou 450001 Henan Province China Department of Occupational and EnvironmentalHealth Sciences College of Public Health Zhengzhou Univer-sity Zhengzhou 450001 Henan Province China Henan Key Laboratory for Esophageal CancerResearch The First Affiliated Hospital College of Basic Medi-cine Zhengzhou University Zhengzhou 450052 Henan ProvinceChina

AIM: To evaluate the association between xeroderma pigmentosum group D (XPD), genetic polymorphism Lys751Gln and esophageal cancer risk. METHODS: We searched PubMed up to September 1, 2010 to identify eligible studies. A total of 10 casecontrol studies including 2288 cases and 4096 controls were included in the meta-analysis. Statistical analysis was performed with Review Manage version 4.2. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the ***: The results suggested that there is no significant association between XPD Lys751Gln polymorphism and esophageal cancer susceptibility in the overall population. However, in subgroup analysis by histology type, a significant association was found between XPD Lys751Gln polymorphism and esophageal adenocarcinoma (for CC vs AA: OR = 1.25, 95% CI = 1.01-1.55, P = 0.05 for heterogeneity). CONCLUSION: Our meta-analysis suggested that XPD Lys751Gln polymorphism may be associated with increased risk of esophageal adenocarcinoma.

关键词： Xeroderma pigmentosum group D Polymorphism Esophageal cancer Mwta-analysis

Photon-interactions with perovskite oxides

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Chinese Physics B 2022年第8期31卷 82-94页

作者： Hongbao Yao er-Jia Guo chen Ge Can Wang Guozhen Yang Kuijuan Jin Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Songshan Lake Materials Laboratory Dongguan 523808China

Photons with variable energy, high coherency, and switchable polarization provide an ideal tool-kits for exploring the cutting-edge scientific questions in the condensed matter physics and material sciences. Over decades, extensive researches in the sample fabrication and excitation have employed the photon as one of the important means to synthesize and explore the low-dimensional quantum materials. In this review, we firstly summarize the recent progresses of the state-of-the-art thin-film deposition methods using excimer pulsed laser, by which syntactic oxides with atomic-unit-cell-thick layers and extremely high crystalline quality can be programmatically fabricated. We demonstrate that the artificially engineered oxide quantum heterostructures exhibit the unexpected physical properties which are absent in their parent forms. Secondly, we highlight the recent work on probing the symmetry breaking at the surface/interface/interior and weak couplings among nanoscale ferroelectric domains using optical second harmonic generation. We clarify the current challenges in the insitu characterizations under the external fields and large-scale imaging using optical second harmonic generation. The improvements in the sample quality and the non-contact detection technique further promote the understanding of the mechanism of the novel properties emerged at the interface and inspire the potential applications, such as the ferroelectric resistive memory and ultrahigh energy storage capacitors.

关键词： laser molecular-beam epitaxy optical second harmonic generation functional oxides

基于区块链的车联网跨域数据安全传输系统设计

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现代电子技术 2025年第1期48卷 71-79页

作者：陈晨王斓凯施佺南通大学信息化中心江苏南通226019 南通大学交通与土木工程学院江苏南通226019

为有效应对车联网系统在数据传输过程中的安全问题,提出一种基于区块链的车联网跨域数据安全传输系统。该系统将车联网安全数据传输过程划分为注册、安全通信与数据共享三个关键环节。在注册阶段,车辆和路边单元需要通过可信机构完成注... 详细信息

为有效应对车联网系统在数据传输过程中的安全问题,提出一种基于区块链的车联网跨域数据安全传输系统。该系统将车联网安全数据传输过程划分为注册、安全通信与数据共享三个关键环节。在注册阶段,车辆和路边单元需要通过可信机构完成注册,以确保其的身份合法性;在通信阶段,为了减少路边单元与车辆频繁认证,设计了跨域认证的方法,保障数据传输的可靠性和完整性,并引入假名来保护用户隐私;在共享阶段,文中设计了基于多线程遍历共享广播森林的事务广播算法,利用广度优先搜索思想建立广播森林,并使用多线程遍历进行数据事务广播传输。实验仿真结果显示,文中方案的签名计算成本减少70%,验证计算成本减少41%;其次,在er模型下,相比使用Gossip协议进行事务数据传输,该方案中交通数据事务总时间降低了93%;在BA模型下降低了87%。

关键词：区块链车联网身份认证密钥协商广播森林数据安全传输系统

Do Ureaplasma urealyticum infections in the genital tract affect semen quality?

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Asian Journal of Andrology 2006年第5期8卷 562-568页

作者： Yan Wang Cui-Ling Liang Jun-Qing Wu chen Xu Shi-Xiao Qin er-Sheng Gao Shanghai Institute of Planned Parenthood Research Fudan University Shanghai 200032 China Department of Epidemiology Shanghai Institute of Planned Parenthood Research Shanghai 200032 China Institute of Population Studies East China Normal University Shanghai 200062 China Department of Histology and Embryology School of Medicine Shanghai Jiaotong University Shanghai 200025 China

Aim： To investigate the relationship between Ureaplasma urealyticum （UU） infection and semen quality. Methods： From 2001 to 2003, 346 eligible patients aged 20-45 years were invited from two hospitals in Shanghai, China, to participate in an investigation which included questionnaires about general and reproductive health, an external genital tract examination, UU culture and semen analysis. Multiple linear regression models were used to examine whether UU had a significant effect on semen quality after adjustment for confounding factors. Results： Findings suggested that UU infection was associated with higher semen viscosity and lower semen pH value. Sperm concentration was lower in UU positive subjects than that in UU negative subjects （54.04 × 10^6/mL vs.70.58 × 10^6/mL）. However, UU did not significantly affect other semen quality indexes. Conclusion： UU infection of the male genital tract could negatively influence semen quality.

关键词： Ureaplasma urealyticum semen quality sperm concentration seminal plasma questionnaire infection