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Chiral Phenol-2NO Ligand Cooperation with Achiral Organic Base in the Zn(II)-Catalyzed Asymmetric Alkylation Reaction of Indoles

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Chinese Journal of Chemistry 2024年第13期42卷 1474-1480页

作者： Ke-Lan xu Yu-Heng Wang Xi-Rui Wang Pan Hu Bo-Wen Pan Wen-Jing Zhang zi-Yue Chen Ying Zhou Xiong-Li Liu National&Local Joint Engineering Research Center for the Exploitation of Homology Resources of Southwest Medicine and Food Guizhou UniversityGuiyangGuizhou 550025China College of Pharmaceutical Sciences Guizhou University of Traditional Chinese MedicineGuiyangGuizhou 550025China Green Catalysis Center and College of ChemistryZhengzhou UniversityZhengzhouHenan 450001China

The privileged C_(2)-symmetric rigid phenol-type ligand is more attractive but challenging in asymmetric ***,we designed and synthesized a class of rigid-featured chiral tridentate Phenol-2NO ligands,that incorporate the advantages of both the phenol skeleton and pyrroloimidazolone-based N-oxide moiety,from readily available L-prolinamides in operationally simple two steps and up to 44%overall *** importantly,using an achiral quinoline derivative as an additive,the newly developed Phenol-2NO ligand could serve as the anioic ligand upon deprotonative activation to coordinate to Zn(II)to form a highly enantioselective catalyst for the asymmetric Michael-type Friedel-Crafts alkylation reaction of indoles with 2,*** yields(up to 90%)and high enantioselectivities(up to 99%ee)are obtained for a wide range of substrates under mild *** and DFT calculations revealed the reaction mechanism and the origins of the *** also represented the first activation of phenol-type ligand/metal complex by an achiral organic base as the additive in asymmetric catalysis.

关键词： Phenol-2NO C_(2)-Symmetric Rigid-featured Tridentate ligand Asymmetric catalysis Alkylation Synthesis design Heterocycles

采用NaI(Tl)晶针阵列的小型单管γ相机的性能研究

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中国科学技术大学学报 2005年第5期35卷 629-633页

作者：祝杰刘士涛雷晓文许咨宗汪兆民中国科学技术大学近代物理系安徽合肥230026

通过实验对采用NaI(Tl)晶针阵列的小型单管γ相机的性能进行了研究,得到的实验结果是:(1)能量响应:对Am-241(59.5 keV)的γ射线能量分辨率为19%;(2)位置线性:绝对非线性1 mm,微分非线性0.67 mm;(3)空间分辨率:半高宽为2.2 mm.得出的结论... 详细信息

通过实验对采用NaI(Tl)晶针阵列的小型单管γ相机的性能进行了研究,得到的实验结果是:(1)能量响应:对Am-241(59.5 keV)的γ射线能量分辨率为19%;(2)位置线性:绝对非线性1 mm,微分非线性0.67 mm;(3)空间分辨率:半高宽为2.2 mm.得出的结论是:(1)采用NaI(Tl)晶针阵列的小型单管γ相机的压缩效应较小;(2)由于晶针单元限制了光子的分布,所以采用NaI(Tl)晶针阵列的小型单管γ相机的空间分辨率基本上由晶针的尺寸大小决定;(3)与平板式NaI(Tl)晶体小型单管γ相机相比,采用NaI(Tl)晶针阵列的小型单管γ相机的能量响应、位置响应和空间分辨率等性能都有一个较大的提高.

关键词： NaI(Tl)晶针阵列能量响应位置线性空间分辨率

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闪烁晶体γ能谱拟合方法的比较

高能物理与核物理 2001年第4期25卷 343-347页

作者：许彤邵明李澄陈宏芳许咨宗中国科学技术大学近代物理系合肥230027

为了确定低光产额的闪烁晶体的光输出 ,人们发展了很多方法来拟合闪烁晶体的γ谱 .本文对这些方法同时用模拟谱和实验谱进行了比较 ,不但考察了它们的拟合结果对真实值的偏差和对光产额相对变化的反映能力。

关键词：闪烁晶体 γ能谱光产额拟合方法钨酸铅晶体(PWO) 高能物理学模拟谱实验谱对撞机康普顿本底

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采用双重交换表示分离的任意说话人语音转换

电子学报 2024年第6期52卷 2141-2150页

作者：章子旭简志华杭州电子科技大学通信工程学院浙江杭州310018

在任意说话人语音转换中,训练阶段通常采用编码器对同一说话人语音进行解耦,然后用解码器进行自重构,而转换阶段的解码器是对源语音的内容信息与目标语音的个性特征进行耦合,因此解码器在转换阶段与训练阶段会存在性能失配现象,影响语... 详细信息

在任意说话人语音转换中,训练阶段通常采用编码器对同一说话人语音进行解耦,然后用解码器进行自重构,而转换阶段的解码器是对源语音的内容信息与目标语音的个性特征进行耦合,因此解码器在转换阶段与训练阶段会存在性能失配现象,影响语音转换性能.对此提出了一种采用双重交换表示分离的语音转换方法DERS-VC(Double Exchange Representation Separation Voice Conversion).该方法在训练阶段的自重构过程中,用同一说话人的语音模拟不同说话人的语音进行自监督训练.训练过程引入转换不变损失和周期循环一致损失,通过双重交换表示分离的循环过程使自重构语音与原始语音更加逼近.实验结果表明,DERS-VC算法在梅尔倒谱距离(Mel-Cepstral Distortion,MCD)上比现有的AGAIN-VC(Activation Guidance and Adaptive Instance Normalization Voice Conversion)转换方法平均降低了4.03%,平均意见分(Mean Opinion Score,MOS)提升了3.62%,转换语音质量和相似度都有提高.这说明,通过双重交换表示分离的方法可以更好地训练解码器,实现更好性能的任意说话人之间的语音转换.

关键词：语音转换任意说话人双重交换表示分离

Millisecond dynamics of colloidal suspension studied by X-ray photon correlation spectroscopy at the Shanghai Synchrotron Radiation Facility

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Nuclear Science and Techniques 2024年第1期35卷 1-9页

作者： Chen-Hui Cui zi-Mu Zhou Lin-Feng Wei Song-Lin Li Feng Tian Xiu-Hong Li Zhi Guo Yi-Hui xu Huai-Dong Jiang Ren-Zhong Tai Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Chinese Academy of SciencesBeijing 100049China Center for Transformative Science ShanghaiTech UniversityShanghai 201210China

X-ray photon correlation spectroscopy(XPCS)has emerged as a powerful tool for probing the nanoscale dynamics of soft condensed matter and strongly correlated materials owing to its high spatial resolution and penetration *** technique requires high brilliance and beam coherence,which are not directly available at modern synchrotron beamlines in *** facilitate future XPCS experiments,we modified the optical setup of the newly commissioned BL10U1 USAXS beamline at the Shanghai Synchrotron Radiation Facility(SSRF).Subsequently,we performed XPCS measurements on silica suspensions in glycerol,which were opaque owing to their high *** were collected using a high frame rate area detector.A comprehensive analysis was performed,yielding correlation functions and several key dynamic *** the results were consistent with the theory of Brownian motion and demonstrated the feasibility of XPCS at ***,by carefully optimizing the setup and analyzing the algorithms,we achieved a time resolution of 2 ms,which enabled the characterization of millisecond dynamics in opaque systems.

关键词： XPCS SSRF Silica suspension Glycerol Brownian motion Millisecond dynamics

Engineered AAV13 variants with enhanced transduction and confined spread

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Zoological Research 2024年第4期45卷 781-790页

作者： Neng-Song Luo Yu-Xiang Cai Zeng-Peng Han Xiao-Kai Sui Wen-Jia Yuan zi-Lian Zhang Hao-Dong Guo Jie Wang Kun-Zhang Lin Fu-Qiang xu Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhanHubei 430074China Shenzhen Key Laboratory of Viral Vectors for Biomedicine Shenzhen-Hong Kong Institute of Brain ScienceShenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenGuangdong 518055China Key Laboratory of Magnetic Resonance in Biological Systems State Key Laboratory of Magnetic Resonance and Atomic and Molecular PhysicsNational Center for Magnetic Resonance in WuhanInnovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhanHubei 430071China Key Laboratory of Quality Control Technology for Virus-Based Therapeutics Guangdong Provincial Medical Products AdministrationNMPA Key Laboratory for Research and Evaluation of Viral Vector Technology in Cell and Gene Therapy Medicinal ProductsBrain Cognition and Brain Disease InstituteShenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenGuangdong 518055China University of Chinese Academy of Sciences Beijing 100049China Zhongnan Hospital Wuhan UniversityWuhanHubei 430072China Brain Case Biotechnology Co. Ltd.ShenzhenGuangdong 518107China College of Life Sciences Wuhan UniversityWuhanHubei 430072China Center for Excellence in Brain Science and Intelligence Technology Chinese Academy of SciencesShanghai 200031China

Precise targeting of specific regions within the central nervous system(CNS)is crucial for both scientific research and gene therapy in the context of brain ***-associated virus 13(AAV13)is known for its restricted diffusion range within the CNS,making it an ideal choice for precise labeling and administration within small brain ***,AAV13 mediates relatively low expression of target ***,we introduced specifically engineered modifications to the AAV13 capsid protein to enhance its transduction *** first constructed AAV13-YF by mutating tyrosine to phenylalanine on the surface of the AAV13 *** then inserted the 7m8 peptide,known to enhance cell transduction,into positions 587/588 and 585/586 of the AAV13 capsid,resulting in two distinct variants named AAV13-587-7m8 and AAV13-585-7m8,*** found that AAV13-YF exhibited superior in vitro infectivity in HEK293T cells compared to AAV13,while AAV13-587-7m8 and AAV13-585-7m8 showed enhanced CNS infection capabilities in C57BL/6 mice,with AAV13-587-7m8 infection retaining a limited spread *** modified AAV13 variants hold promising potential for applications in gene therapy and neuroscience research.

关键词： Adeno-associated virus 13 AAV13-YF AAV13-587-7m8 AAV13-585-7m8 transduction efficiency

Is recovery enhancement after gastric cancer surgery really a safe approach for elderly patients?

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World Journal of Gastrointestinal Oncology 2024年第4期16卷 1334-1343页

作者： zi-Wei Li Xiao-Juan Luo Fei Liu xu-Rui Liu Xin-Peng Shu Yue Tong Quan Lv Xiao-Yu Liu Wei Zhang Dong Peng Department of Gastrointestinal Surgery The First Affiliated Hospital of Chongqing Medical UniversityChongqing 400016China Department of Endoscopy Center The First Affiliated Hospital of Chongqing Medical UniversityChongqing 400012China

BACKGROUND This study aimed to evaluate the safety of enhanced recovery after surgery(ERAS)in elderly patients with gastric cancer(GC).AIM To evaluate the safety of ERAS in elderly patients with *** The PubMed,EMBASE,and Cochrane Library databases were used to search for eligible studies from inception to April 1,*** mean difference(MD),odds ratio(OR)and 95%confidence interval(95%CI)were pooled for *** quality of the included studies was evaluated using the Newcastle-Ottawa Scale *** used Stata(V.16.0)software for data *** This study consists of six studies involving 878 elderly *** analyzing the clinical outcomes,we found that the ERAS group had shorter postoperative hospital stays(MD=-0.51,I2=0.00%,95%CI=-0.72 to-0.30,P=0.00);earlier times to first flatus(defecation;MD=-0.30,I²=0.00%,95%CI=-0.55 to-0.06,P=0.02);less intestinal obstruction(OR=3.24,I2=0.00%,95%CI=1.07 to 9.78,P=0.04);less nausea and vomiting(OR=4.07,I2=0.00%,95%CI=1.29 to 12.84,P=0.02);and less gastric retention(OR=5.69,I2=2.46%,95%CI=2.00 to 16.20,P=0.00).Our results showed that the conventional group had a greater mortality rate than the ERAS group(OR=0.24,I2=0.00%,95%CI=0.07 to 0.84,P=0.03).However,there was no statistically significant difference in major complications between the ERAS group and the conventional group(OR=0.67,I2=0.00%,95%CI=0.38 to 1.18,P=0.16).CONCLUSION Compared to those with conventional recovery,elderly GC patients who received the ERAS protocol after surgery had a lower risk of mortality.

关键词： Enhanced recovery after surgery Gastric cancer Elderly Mortality

基于遗传算法的划分序乘积空间问题求解层选择

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软件学报 2024年第4期35卷 1945-1963页

作者：徐怡邱紫恒安徽大学计算机科学与技术学院安徽合肥230601 计算智能与信号处理教育部重点实验室(安徽大学) 安徽合肥230601

划分序乘积空间作为一种新的粒计算模型,可以从多个视角和多个层次对问题进行描述和求解.其解空间是由多个问题求解层组成的格结构,其中每个问题求解层由多个单层次视角构成.如何在划分序乘积空间中选择问题求解层是一个NP难问题.为此,... 详细信息

划分序乘积空间作为一种新的粒计算模型,可以从多个视角和多个层次对问题进行描述和求解.其解空间是由多个问题求解层组成的格结构,其中每个问题求解层由多个单层次视角构成.如何在划分序乘积空间中选择问题求解层是一个NP难问题.为此,提出一种两阶段自适应遗传算法TSAGA(two stage adaptive genetic algorithm)来寻找问题求解层.首先,采用实数编码对问题求解层进行编码,然后根据问题求解层的分类精度和粒度定义适应度函数.算法第1阶段基于经典遗传算法,预选出一些优秀问题求解层作为第2阶段初始种群的一部分,从而优化解空间.算法第2阶段,提出随当前种群进化迭代次数动态变化的自适应选择算子、自适应交叉算子以及自适应大变异算子,从而在优化的解空间中进一步选择问题求解层.实验结果证明了所提方法的有效性.

关键词：粒计算划分序乘积空间遗传算法问题求解层

基于超图和MuSig2聚合签名的联盟链主从多链共识机制

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电子学报 2024年第3期52卷 803-813页

作者：景旭刘滋雨西北农林科技大学信息工程学院陕西杨凌712100 陕西省农业信息智能感知与分析工程技术研究中心陕西杨凌712100

针对多链式区块链采用主链最终共识机制,导致主链负载大,制约从链性能等问题,论文提出一种基于超图和MuSig2聚合签名的联盟链主从多链共识机制.首先根据超图理论,构建以横贯超图为主链,子超图为从链的联盟链主从多链架构;然后借鉴分治思... 详细信息

针对多链式区块链采用主链最终共识机制,导致主链负载大,制约从链性能等问题,论文提出一种基于超图和MuSig2聚合签名的联盟链主从多链共识机制.首先根据超图理论,构建以横贯超图为主链,子超图为从链的联盟链主从多链架构;然后借鉴分治思想,结合“背书-排序-验证”的共识方式,构建分层分类共识机制,通过分类处理交易降低主链负载压力;最后构建基于MuSig2聚合签名的联盟链多方背书签名方法,提升背书签名的验证效率.性能分析表明:基于MuSig2聚合签名的联盟链多方背书签名安全可靠,基于超图和MuSig2聚合签名的分层分类共识机制具有强一致性和线性时间复杂度.实验结果表明:基于MuSig2聚合签名的多方背书方法的总效率是椭圆曲线数字签名算法(Elliptic Curve Digital Signature Algorithm,ECDSA)的1.55倍,分层分类共识机制能够提升12.5%的共识效率.该机制具有较高性能,可满足企业多样化业务需求.

关键词：区块链联盟链主从多链分层分类共识机制聚合签名超图