检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

木芙蓉花的化学成分研究(Ⅱ)

中药材 2024年第1期47卷 91-95页

作者：叶磊冯丽萍黄李璐冯五文严鑫胡攀夏厚林成都中医药大学药学院四川成都611137 成都市中草药研究所四川成都610016

目的:对锦葵科木槿属植物木芙蓉Hibiscus mutabilis L.的花进行化学成分研究。方法:采用硅胶柱色谱、ODS柱色谱、制备型高效液相色谱等多种分离纯化技术对木芙蓉花的90%乙醇提取物进行分离纯化,并根据核磁数据进行结构鉴定。结果:从木... 详细信息

目的:对锦葵科木槿属植物木芙蓉Hibiscus mutabilis L.的花进行化学成分研究。方法:采用硅胶柱色谱、ODS柱色谱、制备型高效液相色谱等多种分离纯化技术对木芙蓉花的90%乙醇提取物进行分离纯化,并根据核磁数据进行结构鉴定。结果:从木芙蓉花中分离纯化得到17个化合物,分别鉴定为:和厚朴酚(1)、厚朴酚(2)、isohemigossylic acid lactone-2-methyl ether(3)、阿魏酸(4)、3-吲哚甲醛(5)、脱落酸(6)、槲皮素(7)、山柰酚(8)、8-(1-(3,4-dihydroxyphenyl)ethyl-3,3′,4′,5,7-pentahydroxyflavone)(9)、环(脯-缬)二肽(10)、benzyl-β-D-glucopyranoside(11)、山柰酚-3-O-β-D-葡萄糖苷(12)、rhodionin(13)、槲皮素-3-O-(6″-O-反式-对香豆酰基)-β-D-吡喃葡萄糖苷(14)、tiliroside(15)、山柰酚-3-O-(6″-O-顺式-对香豆酰基)-β-D-吡喃葡萄糖苷(16)、山柰酚-7-O-α-L-吡喃鼠李糖苷(17)。结论:其中,化合物1~3、5、6、9~11、14为首次从木槿属植物中分离得到。

关键词：木芙蓉花化学成分分离鉴定

Anti-obesity and Gut Microbiota Modulation Effect of Astragalus Polysaccharides Combined with Berberine on High-Fat Diet-Fed Obese Mice

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Integrative Medicine 2023年第7期29卷 617-625页

作者： YUE Shi-jun WANG wen-xiao ZHANG Lei LIU Juan feng wu-wen GAO Huan TANG Yu-ping YAN Dan Beijing Key Laboratory of Bio-characteristic Profiling for Evaluation of Rational Drug Use Beijing Shijitan HospitalCapital Medical UniversityBeijing100038China Key Laboratory of Shaanxi Administration of Traditional Chinese Medicine for TCM Compatibility Shaanxi University of Chinese MedicineXi’an712046China Department of Pharmacy Beijing Friendship HospitalCaptical UniversityBeijing Institute of Clinical PharmacyBeijing100050China

Objective To investigate whether astragalus polysaccharides(APS)combined with berberine(BBR)can reduce high-fat diet(HFD)-induced obesity in *** Except for normal mice,32 HFD-induced obese mice were randomized into HFD,APS(1,000 mg/kg APS),BBR(200 mg/kg BBR),and APS plus BBR(1,000 mg/kg APS plus 200 mg/kg BBR)groups,*** 6-week treatment(once daily by gavage),the obesity phenotype and pharmacodynamic effects were evaluated by histopathological examination of epididymal fat,liver,and colon using hematoxylin-eosin staining and serum biochemical analyses by an automated chemistry *** feces were collected at the 12 th week,and taxonomic and functional profiles of gut microbiota were analyzed by 16S ribosomal ribonucleic acid(16S rRNA)*** Compared with HFD group,the average body weight of APS plus BBR group was decreased(P<0.01),accompanied with the reduced fat accumulation,enhanced colonic integrity,insulin sensitivity and glucose homeostasis(P<0.05 or P<0.01).Importantly,APS combined with BBR treatment was more effective than APS or BBR alone in improving HFD-induced insulin resistance(P<0.05 or P<0.01).16S rRNA sequence-based analysis of fecal samples demonstrated that APS combined with BBR treatment exhibited a better impact on HFD-induced gut microbiota dysbiosis,exclusively via the enriched abundances of Bacteroides,which corresponded to the large increase of predicted bacterial genes involved in carbohydrate *** APS combined with BBR may synergistically reduce obesity and modulate the gut microbiota in HFD-fed mice.

关键词： Astragalus polysaccharides berberine obesity gut microbiota Bacteroides

Shear-thinning Catechol-modified Chitosan Hydrogel Loaded with Silver Nanoparticles for Endoscopic Submucosal Dissection

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第8期42卷 1147-1155页

作者： wen-Jun feng Yan-He wu Xiao-Yang Liu Zheng-Ke Wang MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhou 310058China

Shear-thinning hydrogels have emerged for endoscopic submucosal dissection,while wound intervention after surgery has rarely been ***,a catechol-modified chitosa n hydrogel with shear-thinning property was developed for simultaneously facilitating endoscopic submucosal dissection and postoperative wound *** from the shear-thinning and self-healing characteristics,the asprepared hydrogel showed easily endoscopic *** also performed very well as submucosal cushion,which could remain above 70%after injection for 120 min in ex vivo porcine large intestine *** fact,the cushion height of normal saline dramatically decreased to 46%of the initial height at 30 *** nanoparticles encapsulated into the network endowed the hydrogel with almost reached 100%antibacterial effect against *** and *** hemolysis ratio of the hydrogel was calculated to be as low as 0.8%.Combined with good hemocompatibility and cytocompatibility,the as-prepared hydrogel displayed much higher in vivo wound closu re and healing efficacy than normal *** results demonstrated the superiority of the shear-thinning chitosan hydrogel in facilitating clinical endoscopic submucosal dissection surgery.

关键词： Shear-thinning hydrogel Endoscopic mucosal dissection Wound healing Catechol-modified chitosan Silver nanoparticles

Heteroepitaxial growth of Au@Pd core–shell nanocrystals with intrinsic chiral surfaces for enantiomeric recognition

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第1期43卷 225-235页

作者： feng-Xia wu feng-Hua Li Xia-Li Lv Qi-Xian Zhang Guo-Bao Xu wen-Xin Niu State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China Shaoxing Institute of Technology Shanghai UniversityShaoxing 312000China University of Science and Technology of China Hefei 230026China School of Materials Science and Engineering Shanghai UniversityShanghai 200436China Zhejiang Institute of Advanced Materials Shanghai UniversityJiashan 314113China University of Chinese Academy of Sciences Beijing 100039China

Noble metal surfaces with intrinsic chirality serve as an ideal candidate for investigating enantioselective chemistry due to their superior chemical durability and high catalytic ***,significant advance has been made in synthesizing metal nanocrystals with intrinsic ***,the majority reports are limited to ***,through a heteroepitaxial growth strategy,the synthesis of metal nanocrystals with intrinsic chirality to palladium was extended for the first time and their application in enantioselective recognition was *** heteroepitaxial growth strategy allows for transferring the chirality of homochiral Au nanocrystals to Au@Pd core–shell *** employing the chiral Au@Pd nanocrystals as enantiomeric recognizing elements,a series of electrochemical sensors for chiral discrimination were *** optimal conditions,the peak potential between D-dihydroxyphenylalanine(D-DOPA)and L-dihydroxyphenylalanine(L-DOPA)is about 80 m V,and the peak current of D-DOPA is 2 times as much as that of L-DOPA,which enables the determination of the enantiomeric excess(EE,%)of ***,this report not only introduces a heteroepitaxial growth strategy to synthesize metal nanocrystals with intrinsic chirality,but also demonstrates the superior capability of integrating intrinsic chirality and catalytic properties into metal nanocrystals for chiral recognition.

关键词： Core–shell nanostructures Chirality transfer Electrochemical sensors Chiral recognition Chiroplasmonics

Recent advances in bioinspired vision systems with curved imaging structures

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第4期43卷 1407-1434页

作者： Ze-Ping He Xun Han wen-Qiang wu Zhang-Sheng Xu Cao-feng Pan CAS Center for Excellence in Nanoscience Beijing Key Laboratory of Micro-Nano Energy and SensorBeijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijing100083China School of Nanoscience and Technology University of Chinese Academy of SciencesBeijing100049China ZJU-Hangzhou Global Scientific and Technological Innovation Center School of Micro-Nano ElectronicsZhejiang UniversityHangzhou311200China Institute of Microscale Optoelectronics Shenzhen UniversityShenzhen518060China

Limited by the planar imaging structure,the commercial camera needs to introduce additional optical elements to compensate for the curved focal plane to match the planar image *** results in a complex and bulky *** contrast,biological eyes possess a simple and compact structure due to their curved imaging structure that can directly match with the curved focal *** by the structures and functions of biological eyes,curved vision systems not only improve the image quality,but also offer a variety of advanced ***,we review the recent advances in bioinspired vision systems with curved imaging ***,we focus on their applications in implementing different functions of biological eyes,as well as the emerging curved neuromorphic imaging systems that incorporate bioinspired optical and neuromorphic processing *** addition,the challenges and opportunities of bioinspired curved imaging systems are also discussed.

关键词： Bioinspired Curved vision system Compound eye Chambered eye Neuromorphic

Absorption properties and mechanism of lightweight and broadband electromagnetic wave-absorbing porous carbon by the swelling treatment

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1701-1712页

作者： Jianghao wen Di Lan Yiqun Wang Lianggui Ren Ailing feng Zirui Jia Guanglei wu College of Materials and Chemistry&Chemical Engineering Chengdu University of TechnologyChengdu 610059China School of Materials Science and Engineering Hubei University of Automotive TechnologyShiyan 442002China Institute of Materials for Energy and Environment State Key Laboratory of Bio-fibers and Eco-textilesCollege of Materials Science and EngineeringQingdao UniversityQingdao 266071China Institute of Physics&Optoelectronics Technology Baoji University of Arts and SciencesBaoji 721016China

Bioderived carbon materials have garnered considerable interest in the fields of microwave absorption and shielding due to their reproducibility and environmental *** this study,KOH was evenly distributed on biomass Tremella using the swelling induction method,leading to the preparation of a three-dimensional network-structured hierarchical porous carbon(HPC)through *** achieved microwave absorption intensity is robust at-47.34 dB with a thin thickness of 2.1 ***,the widest effective absorption bandwidth,reaching 7.0 GHz(11–18 GHz),is attained at a matching thickness of 2.2 *** exceptional broadband and reflection loss performance are attributed to the 3D porous networks,interface effects,carbon network defects,and dipole *** has outstanding absorption characteristics due to its excellent impedance matching and high attenuation *** uniform pore structures considerably optimize the impedance-matching performance of the material,while the abundance of interfaces and defects enhances the dielectric loss,thereby improving the attenuation ***,the impact of carbonization temperature and swelling rate on microwave absorption performance was systematically *** research presents a strategy for preparing absorbing materials using biomass-derived HPC,showcasing considerable potential in the field of electromagnetic wave absorption.

关键词： biomass hierarchical porous carbon dielectric loss electromagnetic wave absorption

A novel refined dynamic model of high-speed maglev train-bridge coupled system for random vibration and running safety assessment

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2024年第7期31卷 2532-2544页

作者： MAO Jian-feng LI Dao-hang YU Zhi-wu CAI wen-feng GUO Wei ZHANG Guang-wen School of Civil Engineering Central South UniversityChangsha 410075China National Engineering Research Center of High-speed Railway Construction Technology Changsha 410075China China Railway Group Limited Beijing 100039China China Railway Eryuan Engineering Group Co. Ltd.Chengdu 610031China

Running safety assessment and tracking irregularity parametric sensitivity analysis of high-speed maglev train-bridge system are of great concern,especially need perfect refinement models in which all properties can be well characterized based on various stochastic excitations.A three-dimensional refined spatial random vibration analysis model of high-speed maglev train-bridge coupled system is established in this paper,in which multi-source uncertainty excitation can be considered simultaneously,and the probability density evolution method(PDEM)is adopted to reveal the system-specific uncertainty dynamic *** motion equation of the maglev vehicle model is composed of multi-rigid bodies with a total 210-degrees of freedom for each vehicle,and a refined electromagnetic force-air gap model is used to account for the interaction and coupling effect between the moving train and track beam bridges,which are directly established by using finite element *** model is proven to be applicable by comparing with Monte Carlo *** applying the proposed stochastic framework to the high maglev line,the random dynamic responses of maglev vehicles running on the bridges are studied for running safety and stability ***,the effects of track irregularity wavelength range under different amplitude and running speeds on the coupled system are *** results show that the augmentation of train speed will move backward the sensitive wavelength interval,and track irregularity amplitude influences the response remarkably in the sensitive interval.

关键词： maglev train-bridge interaction electromagnetic force-air gap model stochastic dynamic analysis running safety assessment probability density evolution method

High-temperature stability of retained austenite and plastic deformation mechanism of ultra-fine bainitic steel isothermally treated below Ms

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

Journal of Iron and Steel Research International 2024年第8期31卷 2014-2030页

作者： Ting-ting He feng Hu Kun Wang wen Zhou Li Li Serhii Yershov Kai-ming wu The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Collaborative Innovation Center for Advanced Steels Wuhan University of Science and TechnologyWuhan 430081HubeiChina Zhejiang Tsingshan Iron and Steel Co. Ltd.Qingtian 323903ZhejiangChina

The mechanical properties of the sample and the stability of retained austenite were studied by designing two kinds of ultra-fine bainitic steel with different heat treatment methods austempering above and below Ms(martensite start tem-perature),which were subjected to tensile tests at 20 and 450℃,*** results show that compared to room temperature(20℃)tensile properties,the uniform elongation of the sample at high temperature(450℃)significantly ***,the uniform elongation of the sample austempered above Ms decreased from 8.0%to 3.5%,and the sample austempered below Ms decreased from 10.9%to 3.1%.Additionally,the tensile strength of the sample austempered above Ms significantly decreased(from 1281 to 912 MPa),and the sample austempered below Ms slightly decreased(from 1010 to 974 MPa).This was due to the high carbon content(1.60 wt.%),high mechanical stability,low thermal stability for the retained austenite of the sample austempered below ***,the retained austenite decomposed at high temper-atures,the carbon content and transformation driving force were significantly reduced,the transformation rate increased,and the phase transformation content reduced.

关键词： Ultra-fine bainite Isothermal treatment High-temperature tensile property Retained austenite stability Plastic deformation

Antimicrobial resistance characteristics and phylogenetic relationships of pleuromutilin-resistant Enterococcus isolates from different environmental samples along a laying hen production chain

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

Journal of Environmental Sciences 2024年第3期137卷 195-205页

作者： Cong Lin Yuxuan feng Xianjun Xie Haoyu Zhang Jie wu Yixiao Zhu Jing Yu Jingyi feng wen Su Shanming Lai Anyun Zhang Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province Key Laboratory of Bio-Resource and Eco-Environment of Ministry of EducationCollege of Life SciencesSichuan UniversityChengdu 610065China

Antimicrobial resistance in the laying hen production industry has become a serious public health *** antimicrobial resistance and phylogenetic relationships of the common conditional pathogen Enterococcus along the laying hen production chain have not been systematically clarified.105 Enterococcus isolates were obtained from 115 environmental samples (air,dust,feces,fies,sewage,and soil) collected along the laying hen production chain (breeding chicken,chick,young chicken,and commercial laying hen).These Enterococcus isolates exhibited resistance to some clinically relevant antibiotics,such as tetracycline (92.4%),streptomycin (92.4%),and erythromycin (91.4%),and all strains had multidrug resistance *** genome sequencing characterized 29 acquired antibiotic resistance genes (ARGs) that conferred resistance to 11 classes of antibiotics in 51pleuromutilin-resistant Enterococcus isolates,and lsa(E),which mediates resistance to pleuromutilins,always co-occurred with lnu(B).Alignments with the Mobile Genetic Elements database identified four transposons (Tn554,Tn558,Tn6261,and Tn6674) with several ARGs(erm(A),ant(9)-la,fex(A),and optrA) that mediated resistance to many clinically important ***,we identified two new transposons that carried ARGs in the Tn554 family designated as Tn7508 and Tn7492.A complementary approach based on conventional multi-locus sequence typing and whole genome single nucleotide polymorphism analysis showed that phylogenetically related pleuromutilin-resistant Enterococcus isolates were widely distributed in various environments on different production *** results indicate that environmental contamination by antimicrobial-resistant Enterococcus requires greater attention,and they highlight the risk of pleuromutilin-resistant Enterococcus and ARGs disseminating along the laying hen production chain,thereby warranting effective disinfection.

关键词： Antimicrobial resistance Enterococcus Laying hen production chain Pleuromutilin