检索结果-南通市图书馆

Deciphering fungal metabolon coupling tandem inverse-electrondemand Diels-Alder reaction and semipinacol rearrangement for the biosynthesis of spiro polycyclic alkaloids

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2025年第01期 288-296页

作者： Shuai Liu Wen-Qiang Xu Ying-Tong Di Man-Cheng Tang Ding-Kang Chen Ming-Ming Cao Yao-Wen Chang Hong-Yu Tang Chun-Mao Yuan Jun-Bo Yang Zhi-Li Zuo Han guo Zi-Fei Xu Ying Zeng yun-Dong Wu Xiao-Jiang Hao Key Laboratory of Phytochemistry and Natural Medicines (Chinese Academy of Sciences) Kunming Institute of Botany Chinese Academy of Sciences University of Chinese Academy of Sciences Lab of Computational Chemistry and Drug Design State Key Laboratory of Chemical Oncogenomics Peking University Shenzhen Graduate School Shenzhen Bay Laboratory State Key Laboratory of Microbial Metabolism School of Life Sciences & Biotechnology Shanghai Jiao Tong University State Key Laboratory of Functions and Applications of Medicinal Plants Guizhou Medical University Molecular Biology Experimental Center Germplasm Bank of Wild Species in Southwest China Kunming Institute of Botany Chinese Academy of Sciences yunnan Key Laboratory for Wild Plant Resources Kunming Institute of Botany Chinese Academy of Sciences Research Unit of Chemical Biology of Natural Anti-Virus Products Chinese Academy of Medical Sciences

In the intricate process of natural product biosynthesis, a metabolon can enhance metabolic flux by associating sequential enzymes. A fungal metabolon, comprising of flavin-dependent monooxygenase Spe F and P450 monooxygenase Spe G, is identified in the biosynthesis of spiro polycyclic alkaloids(+)-notoamide B and its diastereomer(+)-versicolamide B. Using notoamide E as a substance, Spe F/Spe G metabolon can control the stereoselectivity of its 2,3-epoxidation, followed by hydrogen atom ion at C-17 to generate reactive epoxide tau-m A with dienyl iminium unit. Subsequently,(+)-notoamide B and(+)-versicolamide B are produced via tandem nonenzymatic inverse-electron-demand Diels-Alder reaction and semipinacol rearrangement. This provides the first example of metabolon in the biosynthesis of spiro-prenylated indole alkaloids.

关键词：

同方期刊数据库

Recent Progress in Donor-Acceptor Type Conjugated Polymers for Organic Field-effect Transistors

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2023年第5期41卷 652-670,I0006页

作者： Yi-Fan Li yun-Long guo yun-Qi Liu Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic solidsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

The recent progress in the design and synthesis of high-performance donor-acceptor conjugated polymeric semiconducting materials is reviewed from the perspective of multiscale *** multiscale of conjugated polymers is from the primary one-dimensional polymer molecular scale to the secondary polymer-chains interaction scale,and then to the tertiary polymer aggregate *** review focuses on the design and synthesis of polymer molecules,proposes new classification rules,and rationally summarizes the design strategies and modulation methods of *** describe the recent progress from these three aspects:(1)the modification ofπ-conjugated backbone,(2)the evolution of the polymerization methods,and(3)the regulation of aggregate-state structure.

关键词： Conjugated polymers Donor-acceptor Organic field-effect transistors Multiscale optimization

Radial breathing modes of multi-walled carbon nanotubes by an atomic beam-spring model

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2012年第6期55卷 940-946页

作者： miao ChunYang LI HaiJun guo WanLin State Key Laboratory of Mechanics and Control of Mechanical Structures and the Key Laboratory of Intelligent Nano Materials and Devices of MOE and Institute of Nano Science Nanjing University of Aeronautics and AstronauticsNanjing 210016China Maintenance Engineering Division Center of Aviation Safety and TechnologyCivil Aviation Administration of ChinaBeijing 100028China

Based on molecular force fields,a new finite element model is constructed for multi-walled carbon nanotubes where the interlayer interactions and C--C bonds are simulated by the elements of piece-wise linear spring and rectangular cross section beam,*** high computation efficiency and atomic reification,the radial breathing modes of multi-walled carbon nanotubes are studied systemically using this *** results show the correspondence between carbon nanotube structures and vibrational modes,which provide unequivocal data for the experimental characterization of carbon *** empirical relationship of radial breathing modes frequencies with the nanotube radius are also obtained for two-layer carbon nanotubes.

关键词： radial breathing modes multi-walled carbon nanotube atomic beam-spring model

Regression Function Comparison for Paired Data

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2020年第5期33卷 1558-1570页

作者： guo Xu ZHANG Jun FANG yun School of Statistics Beijing Normal UniversityBeijing 100875China College of Mathematics and Statistics Shenzhen UniversityShenzhen 518060China Department of Mathematics Shanghai Normal UniversityShanghai 200234China

In this paper,the regression function comparison for paired data is *** proposed test statistic is based on the weighted integral of characteristic function marked by the difference of *** are several merits of the proposed *** instance,it takes a simple V-statistic *** bandwidth is *** moment conditions are required for *** can be applied to covariates of any fixed *** asymptotic results are also *** is proven that n times the proposed test statistic converges to a finite limit under the null hypothesis and the test is consistent against any fixed *** alternative hypotheses which converge to the null hypothesis at the rate of n-1/2 are also detected.A suitable Bootstrap algorithm is also proposed for the implementation of the proposed test *** studies are carried out to illustrate the merits of the proposed method.A real data example is also used to illustrate the proposed testing procedures.

关键词： Bootstrap characteristic function paired data regression function comparison V-statistic

Strong interactions of incident shock wave with boundary layer along compression corner

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2020年第12期33卷 3149-3157页

作者： Shanguang guo yun WU Hua LIANG Science and Technology on Plasma Dynamics Laboratory Air Force Engineering UniversityXi'an 710038China

The coherent structure and instability of the interaction of incident shock wave with boundary layer developing on a compression corner are experimentally *** experiments are carried out in a supersonic wind tunnel of Mach number *** attention is paid to shock patterns and unsteady shock motions induced by the separation *** high-speed schlieren is used to visualize the flowfield evolution and to characterize the *** snapshot proper orthogonal decomposition of schlieren sequences is applied to investigate the primary coherent structure in the *** Fourier transform and continuous wavelet transformation are applied to characterize the *** results show that there are large-scale low-frequency oscillations of the shock waves and small-scale high-frequency pulsations in the separation *** peak frequency of shock oscillation is mainly concentrated in the range of 100–1000 *** pulsation of the small flow structure in the separation bubble is mainly concentrated above 12.5 k *** on the results of experimental analysis,the preliminary mechanism of the largescale instability of such interaction is obtained.

关键词： Shock wave Boundary layer Interaction Flow mechanism Instability

Physical Properties of Polymers under Soft and Hard Nanoconfinement: A Review

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2020年第6期38卷 565-578页

作者： Ming-Chao Ma yun-Long guo University o f Michigan-Shanghai Jiao Tong University Joint Institute Shanghai Jiao Tong UniversityShanghai 200240China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai200240China

Polymeric materials under nanoconfinements have substantially deviated physical properties with respect to the bulk,especially glass transition temperature,physical aging,and crystallization *** we highlight the leading methods for creating various confinement *** these systems,recent advances on hard and soft confinement effect for glass transition,physical aging,mechanical properties and crystallization of polymers are reviewed in ***,as nanoconfined systems in extreme conditions are experimentally inaccessible,simulation results describing confinement effect on such systems are also discussed.

关键词： Nanoconfinement Glass transition temperature Physical aging Mechanical properties Crystallization

AST-to-ALT ratio and coronary artery lesions among patients with Kawasaki disease

在线全文

学校读者我要写书评

暂无评论

World Journal of Pediatrics 2021年第6期17卷 659-668页

作者： Lei Cao yun-Jia Tang miao Gang Jin Ma Wei-guo Qian Qiu-Qin Xu Hai-Tao Lv Department of Cardiology Children's Hospital of Soochow UniversityNo.92Zhongnan StreetSuzhouChina Department of Pharmacy Children's Hospital of Soochow UniversityNo 92Zhongnan StreetSuzhou.China

Background The aim of this study was to explore the associations between the aspartate aminotransferase-to-alanine aminotransferase ratio(AST/ALT)and coronary artery lesions(CALs)among patients with Kawasaki disease(KD).Methods Medical records of KD patients presenting to a single center between January 2019 and December 2020 were retrospectively collected and ***,multivariable-adjusted analyses,subgroup analyses,restricted cubic spline test,and fitted curves were used to evaluate the associations between AST/ALT and *** A total of 831 patients were enrolled,of which 201(24.2%)had CALs on admission and 21(2.5%)developed CALs de novo after intravenous immunoglobulin(IVIG).Multivariable-adjusted analyses models revealed that a lower AST/ALT was associated with an increased risk of CALs on admission when AST/ALT was a continuous variable(P=0.007)and when it was a categorical variable(P for trend=0.004).Each unit increase in AST/ALT was associated with a 22%lower risk of CALs on admission(odds ratio=0.78,95%confidence interval 0.65-0.94).A negative linear relationship was noted between AST/ALT and the risk of CALs on admission in both observed and fitted ***,such associations were not observed in AST/ALT and CALs de novo after *** of the variables significantly modified the association between AST/ALT and CALs on admission and CALs de novo after IVIG(P>0.05).Conclusion Our findings suggested that AST/ALT was a risk factor of CALs,but was not associated with progressive CALs.

关键词： Alanine aminotransferase Aspartate aminotransferase Coronary artery lesions Kawasaki disease

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2017年第43期23卷 7746-7755页

作者： yun-Wei guo Hui-Biao miao Zhuo-Fu Wen Jie-Ying Xuan Hao-Xiong Zhou Department of Gastroenterology the Third Affiliated Hospital of Sun Yat-Sen University

AIM To focus on procedure-related complications,evaluate their incidence,analyze the reasons and discuss the *** Overall,628 endoscopic gastric variceal obturation(EGVO) procedures(case-times) with NBC were performed in 519 patients in the Department of Endoscopy of the Third Affiliated Hospital of Sun Yat-Sen University from January 2011 to December 2016. The clinical data of patients and procedure-related complications of EGVO were retrospectively *** In the 628 EGVO procedures,sticking of the needle to the varix occurred in 9 cases(1.43%),including 1 case that used lipiodol-diluted NBC and 8 cases that used undiluted NBC(P = 0.000). The needle was successfully withdrawn in 8 cases. Large spurt bleeding occurred in one case,and hemostasis was achieved by two other injections of undiluted glue. The injection catheter became blocked in 17 cases(2.71%) just during the injection,and 4 cases were complicated with the needle sticking to the varix. Large glue adhesion to the endoscope resulted in difficulty withdrawing the endoscope in 1 case. Bleeding from multiple sites was observed in the esophagus and gastric cardia after the endoscope was withdrawn. Hemostasis was achieved by 1% aethoxysklerol injection and intravenous somatostatin. The ligation device stuck to the varices in two cases during the subsequent endoscopic variceal ligation. In one case,the ligation device was successfully separated from the esophageal varix after all bands were released. In another case,a laceration of the vein and massive bleeding were observed. The bleeding ceased after 1% aethoxysklerol *** Although EGVO with tissue glue is usually safe and effective,a series of complications can occur during the procedure that may puzzle endoscopists. There is no standard operating procedure for addressing these complications. The cases described in the current study can provide some reference for others.

关键词： Endoscopic gastric variceal obturation Tissue glue N-butyl-2-cyanoacrylate Complications

High-sensitivity nanophotonic sensors with passive trapping of analyte molecules in hot spots

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Light(Science & Applications) 2021年第1期10卷 60-70页

作者： Xianglong miao Lingyue Yan yun Wu Peter Q.Liu Department of Electrical Engineering University at BuffaloThe State University of New YorkBuffaloNY 14260USA Department of Biomedical Engineering University at BuffaloThe State University of New YorkBuffaloNY 14260

Nanophotonic resonators can confine light to deep-subwavelength volumes with highly enhanced near-field intensity and therefore are widely used for surface-enhanced infrared absorption spectroscopy in various molecular sensing *** enhanced signal is mainly contributed by molecules in photonic hot spots,which are regions of a nanophotonic structure with high-field ***,delivery of the majority of,if not all,analyte molecules to hot spots is crucial for fully utilizing the sensing capability of an optical ***,for most optical sensors,simple and straightforward methods of introducing an aqueous analyte to the device,such as applying droplets or spin-coating,cannot achieve targeted delivery of analyte molecules to hot ***,analyte molecules are usually distributed across the entire device surface,so the majority of the molecules do not experience enhanced field ***,we present a nanophotonic sensor design with passive molecule trapping *** an analyte solution droplet is introduced to the sensor surface and gradually evaporates,the device structure can effectively trap most precipitated analyte molecules in its hot spots,significantly enhancing the sensor spectral response and sensitivity ***,our sensors produce a reflection change of a few percentage points in response to trace amounts of the amino-acid proline or glucose precipitate with a picogram-level mass,which is significantly less than the mass of a molecular monolayer covering the same measurement *** demonstrated strategy for designing optical sensor structures may also be applied to sensing nano-particles such as exosomes,viruses,and quantum dots.

关键词： trapping passive spots