检索结果-南通市图书馆

Cyano migration-mediated radical-polar crossover cyclopropanation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2025年第1期68卷 241-248页

作者： Ziqiang Wang Yasu Chen Jie li Chen Zhu Key Laboratory of Organic Synthesis of Jiangsu Province College of Chemistry Chemical Engineering and Materials ScienceSoochow University Frontiers Science Center for Transformative Molecules Zhangjiang Institute for Advanced Study and Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs Shanghai Jiao Tong University

We report a novel cyano migration-mediated radical-polar crossover process, whereby both the sulfonylcyanation of aliphatic alkenes and the formation of cyclopropanes are concurrently achieved. This transformation yields a diverse array of multisubstituted cyclopropanes under mild photocatalytic conditions. Mechanistic studies elucidate that the reaction proceeds via intramolecular nucleophilic substitution, leading to the formation of the cyclopropane derivatives.

关键词： cyclopropanation cyano migration radical-polar crossover radical reactions

Fine-tuning the spatial allocation of phytohormones for smart canopy, smart breeding, and smart agriculture

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China life Sciences 2025年第1期68卷 309-310页

作者： Tao Zhou lin li National Key Laboratory of Crop Genetic Improvement Huazhong Agricultural University HuBei hongShan Laboratory

The dual challenges of global climate change and population growth have increased demand for higher crop yields per unit area. The innovative technology of smart agriculture aims to synergize breeding, cultivation, and production through the application of biological and informatics technologies. Historically, the “Green Revolution” introduced semidwarf varieties of certain key crops by utilizing mutations affecting gibberellin pathways, which significantly increased planting densities and yields.

关键词：

Activatable chemiluminescence probe based on four-arm PEGconjugated-pyropheophorbide-a for in vivo autofluorescence-free imaging of peroxynitrite

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2025年

作者： Jianmei Ke Lei Ding Ronggui lian Cheng Zheng Wenjun li aixian Zheng Yupeng Sun Ming Wu Yongyi Zeng Xiaolong liu Maochun hong Xiaolong Zhang The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province Mengchao Hepatobiliary Hospital of Fujian Medical University Ganjiang Innovation Academy Chinese Academy of Sciences School of Rare Earths University of Science and Technology of China College of Chemistry Fuzhou University State Key Laboratory of Structure Chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences

Peroxynitrite（ONOO-） is a highly reactive nitrogen species that plays pivotal roles in cell signal transduction and physiological or pathological progresses. However, commonly used ONOO-optical imaging probes are still hampered by high background/autofluorescence（fluorescence probe）, short emission wavelength, or poor selectivity in the case of chemiluminescence. Herein,we report a facile method to prepare an activatable chemiluminescence probe（PPA-PEG） with good biocompatibility and functionality for in vivo autofluorescence-free imaging of ONOO-. The PPA-PEG consists of pyropheophorbide-a（PPA）, a typical deep red photosensitizer that acts as both the recognition and signaling element, and 4-arm poly（ethylene glycol）(4-arm PEG), which improves the biosafety and water solubility of probe. These components can self-assemble into nanoparticles（namely PPA-PEG nanoprobe） in aqueous solution. The PPA-PEG nanoprobe showed an ultra-low chemiluminescence signal before interacting with ONOO-, but exhibited good selectivity, high sensitivity and a fast response toward ONOO-. The PPAPEG was successfully applied to image cellular ONOO-changes, as well as the endogenous ONOO-changes in inflammation models and subcutaneous or orthotopic hepatocellular carcinoma（HCC） tumors models in living mice. In vitro and in vivo studies verified the good detection and imaging capabilities of PPA-PEG for peroxynitrite, demonstrating suitable tissue penetration and a high signal-to-background ratio（SBR）. Thus, our nanoprobe can serve as a valuable activatable chemiluminescence imaging tool for studying important peroxynitrite-related chemical and biological applications.

关键词：

Changes in underflow solid fraction and yield stress in paste thickeners by circulation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2021年第3期28卷 349-357页

作者： hong li ai-xiang Wu hong-Jiang Wang Hui Chen liu-Hua Yang Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mines University of Science and Technology BeijingBeijing 100083China School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China Shandong Taikai Power Electronic Co. Ltd.Taian 271000China

The trouble-free and efficient operation of paste thickeners requires an optimal design and the cooperation of each *** underflow discharging is suspended,alleviating the vast torque that the remaining solids within the thickeners may place on rakes mainly lies in the circulation *** mechanism of this unit was analyzed,and a mathematical model was developed to describe the changes in underflow solid content and yield *** key parameters of the circulation unit,namely,the height and flow rate,were varied to test its performance in the experiments with a self-designed laboratorial thickening *** show that the circulation unit is valid in reducing underflow solid fraction and yield stress to a reasonable extent,and the model could be used to describe its efficiency at different heights and flow rates.A suitable design and application of the circulation unit contributes to a cost-effective operation of paste thickeners.

关键词： paste thickener circulation unit solids content yield stress rake failure

Small extracellular vesicles derived from cerebral endothelial cells with elevated microRNA 27a promote ischemic stroke recovery

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第1期20卷 224-233页

作者： Yi Zhang Zhongwu liu Michael Chopp Michael Millman Yanfeng li Pasquale Cepparulo Amy Kemper Chao li li Zhang Zheng Gang Zhang Department of Neurology Henry Ford HospitalDetroitMIUSA Department of Physics Oakland UniversityRochesterMIUSA Department of Pathology Henry Ford HospitalDetroitMIUSA Division of Pharmacology Department of NeuroscienceReproductive and Dentistry SciencesSchool of MedicineUniversity of Naples“Federico Ⅱ”NaplesItaly

Axonal remodeling is a critical aspect of ischemic brain repair processes and contributes to spontaneous functional *** previous in vitro study demonstrated that exosomes/small extracellular vesicles(sEVs)isolated from cerebral endothelial cells(CEC-sEVs)of ischemic brain promote axonal growth of embryonic cortical neurons and that microRNA 27a(miR-27a)is an elevated miRNA in ischemic *** the present study,we investigated whether normal CEC-sEVs engineered to enrich their levels of miR-27a(27a-sEVs)further enhance axonal growth and improve neurological outcomes after ischemic stroke when compared with treatment with non-engineered CEC-sEVs.27a-sEVs were isolated from the conditioned medium of healthy mouse CECs transfected with a lentiviral miR-27a expression *** EVs isolated from CECs transfected with a scramble vector(Scra-sEVs)were used as a *** male mice were subjected to permanent middle cerebral artery occlusion and then were randomly treated with 27a-sEVs or *** array of behavior assays was used to measure neurological *** with treatment of ischemic stroke with Scra-sEVs,treatment with 27a-sEVs significantly augmented axons and spines in the peri-infarct zone and in the corticospinal tract of the spinal grey matter of the denervated side,and significantly improved neurological *** vitro studies demonstrated that CEC-sEVs carrying reduced miR-27a abolished 27a-sEV-augmented axonal *** analysis revealed that 27a-sEVs systemically administered preferentially localized to the pre-synaptic active zone,while quantitative reverse transcription-polymerase chain reaction and Western Blot analysis showed elevated miR-27a,and reduced axonal inhibitory proteins Semaphorin 6A and Ras Homolog Family Member A in the peri-infarct *** of the Clathrin-dependent endocytosis pathway substantially reduced neuronal internalization of *** data provide evidence that 27a-sEVs have

关键词： axonal remodeling cerebral endothelial cells exosomes miR-27a mitochondria Semaphorin 6A small extracellular vesicles stroke

A Rapid Adaptation Approach for Dynamic air‑Writing Recognition Using Wearable Wristbands with Self‑Supervised Contrastive Learning

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2025年第2期17卷 417-431页

作者： Yunjian Guo Kunpeng li Wei Yue Nam‑Young Kim Yang li Guozhen Shen Jong‑Chul Lee Department of Electronic Convergence Engineering Kwangwoon UniversitySeoul 01897South Korea Radio Frequency Integrated Circuit(RFIC)Bio Centre Kwangwoon UniversitySeoul 01897South Korea Department of Electronic Engineering Kwangwoon UniversitySeoul 01897South Korea School of Microelectronics Shandong UniversityJinan 250101People’s Republic of China State Key Laboratory of Integrated Chips and Systems Fudan UniversityShanghai 200433People’s Republic of China School of Integrated Circuits and Electronics Beijing Institute of TechnologyBeijing 100081People’s Republic of China

Wearable wristband systems leverage deep learning to revolutionize hand gesture recognition in daily *** existing approaches that often focus on static gestures and require extensive labeled data,the proposed wearable wristband with selfsupervised contrastive learning excels at dynamic motion tracking and adapts rapidly across multiple *** features a four-channel sensing array composed of an ionic hydrogel with hierarchical microcone structures and ultrathin flexible electrodes,resulting in high-sensitivity capacitance *** wireless transmission from a Wi-Fi module,the proposed algorithm learns latent features from the unlabeled signals of random wrist ***,only few-shot labeled data are sufficient for fine-tuning the model,enabling rapid adaptation to various *** system achieves a high accuracy of 94.9%in different scenarios,including the prediction of eight-direction commands,and air-writing of all numbers and *** proposed method facilitates smooth transitions between multiple tasks without the need for modifying the structure or undergoing extensive task-specific *** utility has been further extended to enhance human–machine interaction over digital platforms,such as game controls,calculators,and three-language login systems,offering users a natural and intuitive way of communication.

关键词： Wearable wristband Self-supervised contrastive learning Dynamic gesture air-writing Human-machine interaction

Targeting cholesterol trafficking to mitigate axonal degeneration in hereditary spastic paraplegia

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第5期20卷 1397-1398页

作者： Zhenyu Chen Xue-Jun li Department of Biomedical Sciences University of Illinois College of Medicine RockfordRockfordILUSA Department of Bioengineering University of Illinois at ChicagoChicagoILUSA

Axonal degeneration underlies many debilitating diseases including hereditary spastic paraplegia(HSP),a genetically and clinically diverse group of disorders characterized by spasticity and weakness of the lower *** is one significant cause of chronic neurodisability due to the lack of effective treatments and a wide range of onset ages from early childhood to 70 years.

关键词： degeneration diseases hereditary

Double [5]carbohelicene: facile synthesis, chiroptical properties,isomerization study, and lasing application

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2025年第1期68卷 233-240页

作者： Peipei liu Yantong li Meng-Xiang Wu Hao Kang Xiao-li Zhao lin Xu linlin liu Xiaodong li Junfeng Fang Zhiwei Fang Ya Cheng Hai-Bo Yang Huakang Yu Xueliang Shi State Key Laboratory of Petroleum Molecular & Process Engineering Shanghai Key Laboratory of Green Chemistry and Chemical ProcessesSchool of Chemistry and Molecular Engineering East China Normal University School of Physics and Optoelectronics South China University of Technology Institute of Polymer Optoelectronic Materials & Devices State Key Laboratory of Luminescent Materials & Devices South China University of Technology School of Physics and Electronic Science Engineering Research Center of Nanophotonics & Advanced Instrument Ministry of EducationEast China Normal University State Key Laboratory of Precision Spectroscopy School of Physics and Electronic Science East China Normal University

Double carbohelicenes have attracted considerable attention due to their aesthetic structures, distinct π-conjugation extension, inherent chirality, and intriguing optical and electronic properties. Herein, the concise de novo synthesis of a new double[5]carbohelicene 1 together with its chiroptical properties, isomerization process and lasing application is presented. 1 was synthesized by a simple protocol involving the formation of a 6,6′-bipentacene as the key intermediate. It is worth noting that1 existed as two diastereomers 1-PP/MM and 1-PM, which were successfully isolated and unambiguously confirmed by Xray crystallography. The optical resolution of the racemic 1-PP/MM was successfully achieved by chiral-phase highperformance liquid chromatography（HPLC）, and 1-PP and 1-MM were characterized by circular dichroism. Interestingly, it was found that 1-PP/MM could be completely isomerized to 1-PM upon heating, and the detailed thermodynamics and kinetics of the isomerization process were systematically investigated. 1-PM exhibited deep-red luminescence with emission maximum at 723 nm and fluorescence quantum yield as high as 32.95%. Consequently, we can showcase the lasing application of 1-PM by doping with epoxy resin to assemble a bottle microlaser spontaneously, which the lasing wavelength is 796.6 nm at a threshold of 0.8 m J cm-2. We believe that our studies, including the facile synthesis methodology, detailed isomerization studies, and lasing application, will shed some light on the design and synthesis of novel carbohelical systems with more functions.

关键词： double carbohelicene optical resolution organic laser isomerization X-ray diffraction

CO2-mediated bicarbonate conversion to concentrated formate in a CEM-based electrolyzer

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2025年第1期100卷 605-611页

作者： Haocheng Xiong Donghuan Wu Haonan li Andrew li Qikun Hu Siyao Song Bingjun Xu Qi Lu State Key Laboratory of Chemical Engineering Department of Chemical Engineering Tsinghua University College of Chemistry and Molecular Engineering Peking University Ordos Laboratory

Renewable energy-driven bicarbonate conversion to valuable chemicals presents an attractive strategy for mitigating CO2emissions,as bicarbonate can be efficiently generated from the capture of atmospheric CO2using alkaline solutions with reactive *** this work,we present a CO2-mediated bicarbonate conversion to pure formate using a cation exchange membrane-based electrolyzer with a 25 cm2electrode *** electrolysis achieved selectivities exceeding 75%for formate at a total current of 2.5 A,achieving formate concentrations up to 1.2 M and yields as high as 95%over extended *** techno-economic assessment confirmed the economic viability of the process,highlighting the potential for bicarbonate electrolysis as a sustainable method for producing valuable chemicals.

关键词： Electrocatalysis Techno-economic assessments Electrochemistry Flow electrolyzer