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Chiral N-triflylphosphoramide-catalyzed asymmetric hydroamination of unactivated alkenes: a hetero-ene reaction mechanism

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Organic Chemistry Frontiers 2022年第6期9卷 1649-1661页

作者： Na Wang Li-Wen Fan jin Zhang Qiang-Shuai Gu jin-shun lin Guo-Qiang Chen Xin-Yuan Liu Peiyuan Yu College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhen 518071China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China Department of Chemistry and Shenzhen Grubbs Institute Guangdong Provincial Key Laboratory of CatalysisSouthern University of Science and TechnologyShenzhen 518055China Academy for Advanced Interdisciplinary Studies and Department of Chemistry Southern University of Science and TechnologyShenzhen 518055China

A highly enantioselective intramolecular hydroamination reaction catalyzed by chiralN-triflylphosphoramide (NTPA) that features an exceptionally broad substrate scope of isolated unactivated alkenes was recently reported by some of us. Herein we report a detailed density functional theory(DFT) study that unveil an uncommon hetero-ene reaction mechanism for this transformation. The reaction changes from a stepwise mechanism involving discrete tertiary carbocation formation to a concertedmechanism to avoid the generation of energetically unfavorable secondary carbocation species for distinctly substituted alkene substrates. The reactivity of this reaction is primarily affected by the substituentson the internal carbon of the alkene, with the carbocation-stabilizing ones promoting the reaction. Inaddition, the reaction is also influenced by the substituents on the terminal alkene carbons: those diminishing the innate alkene polarization of the starting alkenes retard the reaction by disfavoring the formation of related transition states featuring highly polarized alkene residues. The steric effect of all thesealkene substituents was found to be largely unimportant due to the unique arrangement of the heteroene reaction complex that keeps the reacting alkene away from the sterically congested core region ofthe catalyst pocket. The lower acidity of chiral phosphoric acids than that of chiral NTPAs renders the protonated precomplex along the hetero-ene reaction pathway greatly thermodynamically disfavored. Thisindirectly results in a greater relative distortion in the corresponding transition state, which in turn causesreaction retardation. Our results demonstrate the use of intramolecular pericyclic reactions as an alternative strategy for alkene activation by chiral Brønsted acid catalysis and provide insights into the furtherdevelopment of asymmetric hydrofunctionalization of unactivated alkenes.

关键词： mechanism substituent asymmetric

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High-current pulsed electron beam modification on microstructure and performance of Cu/CuW diffusion bonding joints

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Rare Metals 2024年第6期43卷 2819-2831页

作者： Na-Na Tian Cong-lin Zhang Peng Lyu jin-Tong Guan Jie Cai Qing-Feng Guan shun Guo School of Materials Science and Engineering Jiangsu UniversityZhenjiang 212013China School of Material Science and Engineering Yancheng Institute of TechnologyYancheng 221051China Engineering Institute of Advanced Manufacturing and Modern Equipment Technology Jiangsu UniversityZhenjiang 212013China

This study investigates the influence of high-current pulsed electron beam(HCPEB)modification on the microstructure and shear strength of Cu/CuW *** solid-state diffusion bonding of modified-Cu(MCu)and modified-CuW(M-CuW)was achieved by HCPEB modification pretreatment at a temperature of 800-900℃and a pressure of 5 MPa for 10-50 *** demonstrate that HCPEB modification facilitates the dissolution of W and Cu,resulting in the formation of a Cu_(0.4)W_(0.6)solid solution and thus enhancing the uniform distribution of ***,HCPEB-induced defects play a beneficial role in promoting the diffusion process by providing fast diffusion paths for *** optimal joints with the maximum shear strength of 213.7 MPa were obtained through bonding M-Cu and M-CuW at 900℃and 5 MPa for 30 min,which attributes to the combined effects of fine-grained strengthening and solid solution ***,the application of HCPEB modification showcases its effectiveness in promoting element diffusion and enhancing the mechanical performance of the joints.

关键词： HCPEB Element diffusion Shear strength Crystal defects Surface modification

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Neural-field-assisted transport-of-intensity phase microscopy: partially coherent quantitative phase imaging under unknown defocus distance

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Photonics Research 2024年第7期12卷 1494-1501页

作者： YANBO jin linPENG LU shun ZHOU JIE ZHOU YAO FAN CHAO ZUO Smart Computational Imaging Laboratory(SCILab) School of Electronic and Optical EngineeringNanjing University of Science and TechnologyNanjing 210094China Smart Computational Imaging Research Institute(SCIRI)of Nanjing University of Science and Technology Nanjing 210019China Jiangsu Key Laboratory of Spectral Imaging&Intelligent Sense Nanjing 210094China

The transport-of-intensity equation(TIE) enables quantitative phase imaging(QPI) under partially coherent illumination by measuring the through-focus intensities combined with a linearized inverse reconstruction algorithm. However, overcoming its sensitivity to imaging settings remains a challenging problem because of the difficulty in tuning the optical parameters of the imaging system accurately and because of the instability to long-time measurements. To address these limitations, we propose and experimentally validate a solution called neural-field-assisted transport-of-intensity phase microscopy(NFTPM) by introducing a tunable defocus parameter into neural field. Without weak object approximation, NFTPM incorporates the physical prior of partially coherent image formation to constrain the neural field and learns the continuous representation of phase object without the need for training. Simulation and experimental results of He La cells demonstrate that NFTPM can achieve accurate, partially coherent QPI under unknown defocus distances, providing new possibilities for extending applications in live cell biology.

关键词： field. coherent phase

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Genomics,transcriptomics,and peptidomics of the greater wax moth Galleria mellonella neuropeptides and their expression in response to lead stress

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Insect Science 2024年第3期31卷 773-791页

作者： Li-lin Luo Yang lin Jun-Hong linghu Wei Gong Yuan-Hong Luo Man Liu Dao-Chao jin Guy Smagghe Tong-Xian Liu shun-Hua Gui Tian-Ci Yi Guizhou Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region Institute of EntomologyGuizhou UniversityGuiyangGuizhouChina Guizhou Institute of Biology Guizhou Academy of SciencesGuiyangChina Institute of Plant Health and Medicine Guizhou UniversityGuiyangChina

Neuropeptides are crucial in regulation of a rich variety of developmental,physiological,and behavioral functions throughout the life cycle of *** an integrated approach of multiomics,we identified neuropeptide precursors in the greater wax moth Galleria mellonella,which is a harmful pest of honeybee hives with a worldwide ***,a total of 63 and 67 neuropeptide precursors were predicted and annotated in the *** genome and transcriptome,in which 40 neuropeptide precursors were confirmed in the *** ***,we identified 12 neuropeptide precursor genes present in *** but absent in honeybees,which may be potential novel pesticide target *** hives were contaminated with heavy metals such as lead,enabling its bioaccumulation in *** bodies through the food chain,we performed transcriptome sequencing to analyze the effects of Pb stress on the mRNA expression level of *** neuropeptide *** treatment by Pb,the expression of neuropeptide F1 was found to be significantly downregulated,implying that this neuropeptide might be associated with responding to the heavy metal stress in *** study comprehensively identified neuropeptide precursors in ***,and discussed the effects of heavy metals on insect neuropeptides,with the example of *** results are valuable for future elucidation of how neuropeptides regulate physiological functions in *** and contribute to our understanding of the insect's environmental plasticity and identify potential new biomarkers to assess heavy metal toxicity in insects.

关键词： Galleria mellonella genomics heavy metal stress neuropeptide peptidomics transcriptomics

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Copper-Catalyzed Redox-Triggered Remote C--H Functionali- zation： Highly Selective Formation of C--CF3 and C--O Bonds

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Chinese Journal of Chemistry 2016年第5期34卷 490-494页

作者： Taotao Li Peng Yu jin-shun lin Yonggang Zhi Xin-Yuan Liu Chengdu Institute of Organic Chemistry Chinese Academy ofSeienees Chengdu Sichuan 610041 China Department of Chemistry South University of Science and Technology of China Shenzhen Guang dong 518055 China

A Cu-catalyzed remote sp3 C--H/unactivated alkenes functionalization reaction for the concomitant construc- tion of C--CF3 and C--O bonds was described. An 1,5-H radical transfer involving an sp3 C--H bond adjacent to a nitrogen atom and an a-CF3-alkyl radical intermediate derived from unactivated alkenes was observed and demon- strated to proceed via the radical process.

关键词： alkenes radical trifluoromethylation 1,5-H radical transfer Togni's reagent

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Investigation on the influence of vortex generator on particle resuspension

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Particuology 2024年第3期86卷 126-136页

作者： Dongchi Yu Jun-Li lin jin-Han Xie ASML 80W Tasman DrSan Jose95134CaliforniaUSA Department of Mechanics and Engineering Science at College of Engineering and State Key Laboratory for Turbulence and Complex Systems Peking UniversityBeijing100081China

The vortex generator(VG)and its well-known effect in flow optimization are widely studied and employed across different engineering ***,while the same working principles of VG may be well suited for the applications on surface-cleaning technologies,such promising potential is hardly,if any,explored in the published ***,in the present study,the influence on flow-induced particle resuspension brought by a rectangular vG in a channel flow is investigated with the help of highfidelity computational fluid dynamics *** increases of particle removal forces and resuspension rates are discovered in long,strip-like regions with reduced boundary-layer thickness resulted from the vG-induced vortices,and the enhancement effect is especially significant for configurations with the VG installed at a greater angle of *** is also shown that while the resuspension enhancements on the lower and the upper surfaces of the channel exhibit distinct statistical characteristics,having a VG in the channel improves the overall particle-removing capability of the channel flow by introducing higher surface-averaged removal forces and particle resuspension *** but not least,the increase of resuspension rate is especially significant for the smaller,micron-scale particles which are otherwise hardly disturbed by a VG-less channel flow,and such resuspension-enhancement effectgenerally subsides with increasing particle size.

关键词： Particle resuspension Vortexgenerator CFD Surface cleaning

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Clinical and genomic analysis of baseline and acquired MET fusions with an intact kinase domain in lung cancer patients

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Genes & Diseases 2024年第1期11卷 76-79页

作者： Bo jin Yutong Ma Qian Wu Qiuxiang Ou Yang Shao shun Xu Department of Medical Oncology The First Hospital of China Medical UniversityShenyangLiaoning 110001China Geneseeq Research Institute Nanjing Geneseeq Technology Inc.NanjingJiangsu 210000China School of Public Health Nanjing Medical UniversityNanjingJiangsu 211166China Department of Thoracic Surgery The First Hospital of China Medical UniversityShenyangLiaoning110001China

MET gene alterations in lung cancer patients mainly include exon 14 skipping and gene amplification,which are the key therapeutic targets and drive resistance to tyrosine kinase inhibitors(TKls).1 However,the structural variants of MET,such as MET fusions,are much rarer(0.26%),as reported in a Chinese non-small cell lung cancer(NSCLC)cohort.2 Several recurrent MET fusions,such as KIF5B-MET and HLADRB1-MET,were reported as oncogenic drivers and showed favorable responses to crizotinib.

关键词： lung patients alterations

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Experimental investigation of vibration pretreatment-microwave curing process for carbon fiber reinforced resin matrix composites

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Journal of Central South University 2024年第6期31卷 1838-1855页

作者： ZHANG De-chao ZHAN Li-hua MA Bo-lin YAO shun-ming GUO jin-zhan GUAN Cheng-long LIU Shu Light Alloys Research Institute Central South UniversityChangsha 410083China College of Mechanical and Electrical Engineering Central South UniversityChangsha 410083China School of Mechanical Engineering and Automation Fuzhou UniversityFuzhou 350108China

The vibration pretreatment-microwave curing process is an efficient,low energy consumption,and high-quality out-of-autoclave curing process for carbon fiber resin matrix *** study aims to investigate the impact of vibration pretreatment temperature on the fiber weight content,microscopic morphology and mechanical properties of the composite laminates by using optical digital microscopy,universal tensile testing machine and thermo-gravimetric ***,the combined mode of Bragg fiber grating sensor and temperature measurement fiber was employed to explore the effect of vibration pretreatment on the strain process during microwave *** study results revealed that the change in vibration pretreatment temperature had a slight impact on the fiber weight content when the vibration acceleration remained *** metallographic and interlaminar strength of the specimen formed at a vibration pretreatment temperature of 80℃ demonstrated a porosity of 0.414% and a 10.69% decrease in interlaminar shear strength compared to autoclave ***,the introduction of the vibration energy field during the microwave curing process led to a significant reduction in residual strain in both the 0°and 90°fiber directions,when the laminate was cooled to 60℃.

关键词： vibration microwave curing porosity interlaminar shear strength thermo-gravimetric analysis curing strain

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The effect of Ti and Zr content on the structure,mechanics and energy-release characteristics of Ti—Zr—Ta alloys

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Defence Technology（防务技术） 2024年第1期31卷 343-350页

作者： Jia-yu Meng jing-zhi He Bin Zhang jin Chen shun Li Dun Niu Yu Tang Xi’an Modern Chemistry Research Institute Xi'an710065China College of Aerospace Science and Engineering National University of Defense TechnologyChangsha410073China

Energetic structural materials(ESMs)are a new type of structural materials with bearing and damage *** this work the microstructure,mechanical properties and energy release characteristics of multi-element Ti-Zr-Ta alloys with good casting performance were *** microstructure of the Ti_(x)ZrTa alloys gradually change from BCC+HCP to single BCC structure with the increase of *** the Ti_(2)Zr_(y)Ta alloys was still uniform and single BCC structure with the increase of *** evolution of microstructure and composition then greatly affect the mechanical properties and energy-release characteristics of Ti-Zr-Ta *** synergistic effect of dual phase structure increases the fracture strain of Ti_(x)ZrTa(x=0.2,0.5)with the Ti content decreases,while the fracture strain of Ti_(x)ZrTa(x=2.0,3.0,4.0)gradually increase with the Ti content increases caused by the annihilation of the obstacles for dislocation *** as Zr content increases,the fracture strain of Ti_(2)Zr_(y)Ta alloys decrease,then the oxidation reaction rate and fragmentation degree gradually *** higher oxidation rate and the lager exposed oxidation area jointly leads the higher releasing energy efficiency of Ti_(x)ZrTa alloys with low Ti content and Ti_(2)Zr_(y)Ta alloys with high Zr content.

关键词： Energetic structural materials Ti-Zr-Ta Multi-element alloy Energy release characteristics

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Effect of Menopausal Hormone Replacement Therapy on Cytokine Patterns in a Perimenopausal Mouse Model Established by the Ovarian Castration Method

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Chinese Journal of Biomedical Engineering(English Edition) 2024年第1期33卷 40-48页

作者： HE Bin-bin ZHANG Ju-shun WANG jin-yong Longyan First Affiliated Hospital of Fujian Medical University Longyan Fujian 364000China

Objective: To investigate the effect of perimenopausal hormone replacement therapy(HRT) on cytokine patterns in a perimenopausal mouse model established by ovarian castration. Methods: The mice were divided into natural menopause group,ovariectomy group and HRT group, with 15 mice in each group, and the estrous cycle, estrous frequency and menopausal time of the mice were determined by vaginal cytology,and the estrous cycle, estrous frequency and menopausal time were compared among the three groups. The serum levels of estradiol(E2) and progesterone(P4) in each group were detected by double-antibody sandwich ELISA, and the levels of interferon gamma(IFN-γ), interleukin-2(IL-2), IL-4 and IL-10 in the spleen γ tissues of mice were detected by ELISA. Results: The time of menopause(53.07±3.99) d in the HRT group was between that of the natural menopause group(80.80±3.26) d and that of the ovariectomy group(16.27±4.35) d, with a statistically significant difference in the two-by-two comparison of the three groups(P<0.05). The levels of serum E2(694.4±128.3) ng/L and P4(14.2 ±6.0) ng/L in the HRT therapy group are between those of the ovariectomy group and the natural menopause group, with statistically significant differences between the groups(P<0.05). The levels of IL-2(30.9±5.3) pg/ml, IL-4(9.4±1.6) pg/ml, IL-10(19.7±3.1) pg/ml, IFN-γ(22.0±3.7) pg/ml in the HRT group were all between those of natural menopause group and ovariectomy group. The Th1/Th2 ratio in the ovariectomy group was 7.55±1.57, higher than that in the natural menopause group(1.53±0.48) and HRT group(2.38 ±0.44), with statistically significant differences(P<0.05). Conclusion:Menopausal HRT can partially correct the imbalance of Th1/Th2 cytokines, which is able to provide an experimental basis for the regulation of menopause-related immune imbalance by HRT.

关键词： menopause hormone replacement therapy(HRT) ovariectomy mouse model cytokine pattern

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