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Recent advance in carbocation-catalyzed reactions

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Chinese Chemical Letters 2023年第2期34卷 18-32页

作者： Wei xiao jie Wu School of Pharmaceutical and Materials Engineering&Institute for Advanced Studies Taizhou UniversityTaizhou 318000China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China School of Chemistry and Chemical Engineering Henan Normal UniversityXinxiang 453007China

Carbocations such as tropylium and trityl cation, can be stable enough to be isolated and used without inert conditions. They can act as Lewis acids to lower the LUMO of electrophile, thus promoting reactions with nucleophiles. Additionally, the interaction between carbocations and alcohols can form Bronsted acids with enhanced acidity. Furthermore, electrophoto activation of TAC^(+)(trisaminocyclopropenium ion)delivers the excited radical dication TAC·^(2+*), which is a strong oxidant and capable of oxidizing a range of challenging substrates. Moreover,^(n)Pr-DMQA^(+) is disclosed as a versatile photoredox catalyst as its excited state can be quenched through both oxidation and reduction. This review summarizes recent advance in carbocation-catalyzed reactions. These developed methods provide an environmentally friendly pathway for the synthesis of valuable compounds and will inspire chemists to discover more interesting transformations promoted by carbocations.

关键词： Carbocation Lewis acid Photoredox catalysis Tropylium cation Trityl cation

Incidence Category of the Young Lattice,Injections Between Finite Sets,and Koszulity

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Algebra Colloquium 2021年第2期28卷 195-212页

作者： Brendan Dubsky Jie XIAO Department of Mathematics Uppsala UniversityUppsalaSweden 不详

We study the quadratic quotients of the incidence category of the Young lattice defined by the zero relations corresponding to adding two boxes to the same row,or to the same column,or both.We show that the last quotient corresponds to the Koszul dual of the original incidence category,while the first two quotients axe,in a natural way,Koszul duals of each other and hence they axe in particular Koszul self-dual.Both of these two quotients are known to be basic representatives in the Morita equivalence class of the category of injections between finite sets.We also present a new,rather direct,argument establishing this Morita equivalence.

关键词： Young lattice Koszulity category of injections Koszul duality

Pt–C interactions in carbon-supported Pt-based electrocatalysts

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Frontiers of Chemical Science and Engineering 2023年第11期17卷 1677-1697页

作者： Yu-Xuan xiao jie Ying Hong-Wei Liu xiao-Yu Yang School of Chemical Engineering and Technology Sun Yat-sen UniversityZhuhai 519082China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing&Shenzhen Research Institute&Joint Laboratory for Marine Advanced Materials in Pilot National Laboratory for Marine Science and Technology(Qingdao) Wuhan University of TechnologyWuhan 430070China

Carbon-supported Pt-based materials are highly promising electrocatalysts.The carbon support plays an important role in the Pt-based catalysts by remarkably influencing the growth,particle size,morphology,dispersion,electronic structure,physiochemical property and function of Pt.This review summarizes recent progress made in the development of carbon-supported Pt-based catalysts,with special emphasis being given to how activity and stability enhancements are related to Pt–C interactions in various carbon supports,including porous carbon,heteroatom doped carbon,carbon-based binary support,and their corresponding electrocatalytic applications.Finally,the current challenges and future prospects in the development of carbon-supported Pt-based catalysts are discussed.

关键词： Pt-C interactions Pt-based materials carbon support electrocatalysis

Nanomaterial-based delivery vehicles for therapeutic cancer vaccine development

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Cancer Biology & Medicine 2021年第2期18卷 352-371页

作者： jie Liang xiao Zhao CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety&CAS Center for Excellence in Nanoscience National Center for Nanoscience and Technology of ChinaBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Nanomaterial-based delivery vehicles such as lipid-based,polymer-based,inorganics-based,and bio-inspired vehicles often carry distinct and attractive advantages in the development of therapeutic cancer vaccines.Based on various delivery vehicles,specifically designed nanomaterials-based vaccines are highly advantageous in boosting therapeutic and prophylactic antitumor immunities.Specifically,therapeutic vaccines featuring unique properties have made major contributions to the enhancement of antigen immunogenicity,encapsulation efficiency,biocompatibility,and stability,as well as promoting antigen cross-presentation and specific CD8^(+)T cell responses.However,for clinical applications,tumor-associated antigen-derived vaccines could be an obstacle,involving immune tolerance and deficiency of tumor specificities,in achieving maximum therapeutic indices.However,when using bioinformatics predictions with emerging innovations of in silico tools,neoantigen-based therapeutic vaccines might become potent personalized vaccines for tumor treatments.In this review,we summarize the development of preclinical therapeutic cancer vaccines and the advancements of nanomaterial-based delivery vehicles for cancer immunotherapies,which provide the basis for a personalized vaccine delivery platform.Moreover,we review the existing challenges and future perspectives of nanomaterial-based personalized vaccines for novel tumor immunotherapies.

关键词： Nanomaterial-based delivery vehicles bioinformatic prediction neoantigen personalized vaccines tumor immunotherapy

Two drifting paths of Sargassum bloom in the Yellow Sea and East China Sea during 2019-2020

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Acta Oceanologica Sinica 2022年第6期41卷 78-87页

作者： Chao Yuan Jie XIAO Xuelei Zhang Mingzhu Fu Zongling Wang The MNR Key Laboratory of Marine Eco-Environmental Science and Technology First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China Laboratory of Marine Ecology and Environmental Science Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China National Engineering Laboratory for Integrated Aero-Space-Ground-Ocean Big Data Application Technology Xi'an 710129China

The macroalgal blooms of floating brown algae Sargassum horneri are increasing in the Yellow Sea and East China Sea during the past few years.However,the annual pattern of Sargassum bloom is not well characterized.To study the developing pattern and explore the impacts from hydro-meteorologic environment,high resolution satellite imageries were used to monitor the distribution,coverage and drifting of the pelagic Sargassum rafts in the Yellow Sea and East China Sea from September 2019 to August 2020.Sargassum blooms were detected from October 2019 to June 2020 and presented two successive drifting paths that both initiated from around 37°N.The first path spanned smaller spatial scale and shorter period,starting with a bloom of 3 km^(2) distribution area near the eastern tip of Shandong Peninsula in late October 2019 and drifted southwards,hit the Pyropia aquaculture area in early January 2020,then vanished in the northwest of East China Sea(ca.32°N)around end of January.The second path began with a large distribution area of 23000 km^(2) east of 123°E in late January 2020,firstly moved southwards in the central Yellow Sea and northern East China Sea(north of 29°N)till late April,then turned northwards with monsoon wind and vanished from late June to August.The mean sea surface temperature of 8℃ to 20℃ in the Sargassum bloom areas corresponded to in situ observed temperature range for vegetative growth and floating of S.horneri.There was no observed floating Sargassum blooms during July through September in the Yellow Sea and East China Sea.The results indicate that floating S.horneri is unable to complete life cycle in the Yellow Sea and East China Sea,and provide insights to the future management of Sargassum blooms.Further studies are needed to validate the pattern and source of annual Sargassum bloom in the Yellow Sea and East China Sea.

关键词： Sargassum horneri macroalgal bloom high resolution remote sensing wind directions sea surface temperature Yellow Sea and East China Sea

Piperine regulates the circadian rhythms of hepatic clock gene expressions and gut microbiota in high-fat diet-induced obese rats

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Food Science and Human Wellness 2024年第3期13卷 1617-1627页

作者： Weiyun Zhang Chi-Tang Ho Wenlian Wei Jie XIAO Muwen Lu Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods College of Food ScienceSouth China Agricultural UniversityGuangzhou 510642China Department of Food Science Rutgers UniversityNew Brunswick 08901USA

The interplay between the host circadian clock and microbiota has significant influences on host metabolism processes,and circadian desynchrony triggered by high-fat diet(HFD)is closely related to metabolic disorders.In this study,the modulatory effects of piperine(PIP)on lipid metabolism homeostasis,gut microbiota community and circadian rhythm of hepatic clock gene expressions in obese rats were investigated.The Sprague-Dawley(SD)rats were fed with normal diet(ND),HFD and HFD supplemented with PIP,respectively.After 9 weeks,rats were sacrificed with tissue and fecal samples collected for circadian analysis.Results showed that chronic PIP administration ameliorated the obesity-induced alterations in lipid metabolism and dysregulation of hepatic clock gene expressions in obese rats.The gut microbial communities studied through 16S rRNA sequencing showed that PIP ameliorated the imbalanced nicrobiota and recovered the circadian rhythm of Lactobacillaceae,Desulfovibrionaceae,Paraprevotellaceae,and Lachnospiraceae.The fecal metabolic profiles indicated that 3-dehydroshikimate,cytidine and lithocholyltaurine were altered,which were involved in the amino acid and fatty acid metabolism process.These findings could provide theoretical basis for PIP to work as functional food to alleviate the lipid metabolism disorder,circadian rhythm misalignment,and gut microbiota dysbiosis with wide applications in the food and pharmaceutic industries.

关键词： Piperine Circadian clock Obesity Gut microbiota

Strong earthquake clustering around the eastern Tibetan Plateau after the 2008 MW7.9 Wenchuan earthquake

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Science China Earth Sciences 2020年第7期63卷 999-1012页

作者： Duyuan XU Jie XIAO Jiankun HE Weimin WANG Key Laboratory of Continental Collision and Plateau Uplift Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China CAS Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of SciencesBeijing 100101China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

After the 2008 M_W7.9 Wenchuan earthquake,the eastern Tibetan Plateau experienced a series of M_W>6.0 earthquakes,including the 2013 M_W6.6 Lushan,2014 M_W6.1 Kangding and 2017 M_W6.5 Jiuzhaigou events.Based on available constraints,we build a three-dimensional viscoelastic finite element model to calculate Coulomb failure stress caused by these strong earthquakes.In this model,the geometry and slip vector of the initial rupture zone of each earthquake are used to better evaluate the earthquake-related stress projection.Considering reasonable ranges of viscosities for the crust and upper mantle in different tectonic units,numerical results show that after the Wenchuan earthquake,the coseismic Coulomb failure stress change at the hypocenters of the subsequent earthquakes increased to approximately+0.012–+0.040,+0.01–+0.03,and+0.008–+0.015 MPa,respectively.With viscoelastic relaxation of the lower crust and upper mantle,the Coulomb failure stress change at the hypocenters of these earthquakes accumulated to about+0.014–+0.042,+0.016–+0.036,and+0.003–+0.007 MPa just before their occurrence.This suggests that the Wenchuan earthquake indeed triggered or hastened the occurrence of the Lushan,Kangding and Jiuzhaigou events,supporting that strong earthquake clustering around the eastern Tibetan Plateau could be related to stress interaction between the seismogenic faults.Besides,~94%and^6%of the stress increase around(and before the occurrence of)the Kangding earthquake were contributed by the Wenchuan event and the Lushan event,respectively;the positive Coulomb failure stress change at the Jiuzhaigou earthquake hypocenter was related to coseismic slip partitioning of the Wenchuan earthquake.This means that stress interaction among the earthquakes could be controlled by the combined effect of stress of the previous events and by the complexity of earthquake ruptures.Thus,in researches on the earthquake-triggering mechanism,special attentions should be paid on both details of the rupture model and multiple factors of prev

关键词： Earthquake clustering Viscoelastic stress triggering Finite element modeling Wenchuan earthquake Eastern Tibetan Plateau

Vibrations of tandem cold rolling mill: coupled excitation of rolling force and variable stiffness of fault-free back-up roll bearing

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Journal of Iron and Steel Research(International) 2023年第9期30卷 1792-1802页

作者： Yu-jie Liu Shen Wang jie-bin Qi xiao-qiang Yan School of Mechanical Engineering University of Science and Technology BeijingBeijing 100083China Department of Mechanical Engineering and Mechanics Lehigh UniversityBethlehemCommonwealth of Pennsylvania 18015USA

Vibration issues of a five-stand tandem cold rolling mill were found in the steel production practice,and the experimental observation and numerical analysis indicated that the vibrations were related to the back-up roll bearing.The results were validated by replacing the back-up roll bearing with the new bearing resulting in 30%decline in vibration amplitude.Models describing the four-row cylindrical roller bearing and the vertical system of the cold rolling mill including the bearing were established.Moreover,the mechanisms of periodic excitation and amplified vibrations of fault-free bearing were explained theoretically,along with the analysis of bifurcation behaviors of the motion states of the roller bearing and rolling mill system.It is found that the energy transmitted between vibrations with different frequencies if multiple excitation frequencies in the rolling mill system were close.

关键词： Rolling mill vibration Cold tandem mill Fault-free bearing Vibration amplification Variable stiffness Characteristics

Global Existence of Strong Solutions for the Generalized Navier-Stokes Equations with Damping

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Acta Mathematicae Applicatae Sinica 2022年第3期38卷 627-634页

作者： xiao-jing CAI Yan-jie ZHOU School of mathematics and statistics Beijing Technology and Business UniversityBeijing 100048China

This paper mainly focus on the global existence of the strong solutions for the generalized NavierStokes equations with damping. We obtain the global existence and uniqueness when α ≥5/4 for β ≥ 1 and when 1/2+β/... 详细信息

关键词： generalized Navier-Stokes equations damping global existence