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chinese chemical Letters 2024年第5期35卷 135-140页

作者： Zhen Liu Zhi-Yuan Ren chen Yang xiangyi Shao Li chen xin Li State Key Laboratory of Elemento-Organic chemistry Frontiers Science Center for New Organic MatterCollege of ChemistryNankai UniversityTianjin 300071China Haihe Laboratory of Sustainable chemical Transformations Tianjin 300192China Zhenhai High School of Zhejiang Ningbo 315299China

catalytic enantioselective alkenylation is an efficient method to construct chiral alkene molecules,but the asymmetric alkenylation of simple alkenes catalyzed by metal-free catalysts remains an elusive ***,we reported an asymmetric alkenylation of benzoxazinones with diarylethylenes by utilizing a B(c_(6)F_(5))_(3)/chiral phosphoric acid catalyst.A broad of benzoxazinones and diarylethylenes with electron-withdrawing and electron-donating groups were tolerated(up to 95%yield and 97.5:2.5 e.r.)in the methodology under mild reaction ***,the synthetic utility was confirmed by the scaled-up reaction and transformations of the *** mechanism was preliminarily explored by control reactions,nonlinear effect experiment and DFT calculations.

关键词： Asymmetric alkenylation Simple alkenes Benzoxazinones B(c_(6)F_(5))_(3)/chiral phosphoric acid Theoretical calculations

Pleistocene glaciation advances the cryptic speciation of Stellera chamaejasme *** a major biodiversity hotspot

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Journal of Integrative Plant Biology 2024年第6期66卷 1192-1205页

作者： Santosh Kumar Rana Hum Kala Rana Jacob BLandis Tianhui Kuang Juntong chen Hengchang Wang Tao Deng charles c.Davis Hang Sun cAS Key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China Arkansas Biosciences Institute Arkansas State UniversityJonesboroArkansas 72401USA School of Integrative Plant Science Section of Plant Biology and the L.H.Bailey HortoriumCornell UniversityIthacaNew York 14853USA BTI computational Biology center Boyce Thompson InstituteIthacaNew York 14853USA cAS Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture Chinese Academy of SciencesWuhan Botanical GardenWuhan 430074China Department of Organismic and Evolutionary Biology HerbariaHarvard UniversityCambridgeMassachusetts 02138USA

The mountains of Southwest china comprise a significant large mountain range and biodiversity hotspot imperiled by global climate *** high species diversity in this mountain system has long been attributed to a complex set of factors,and recent large-scale macroevolutionary investigations have placed a broad timeline on plant diversification that stretches from 10 million years ago(Mya)to the *** our increasing understanding of the temporal mode of speciation,finer-scale populationlevel investigations are lacking to better refine these temporal trends and illuminate the abiotic and biotic influences of cryptic *** is largely due to the dearth of organismal sampling among closely related species and populations,spanning the incredible size and topological heterogeneity of this *** study dives into these evolutionary dynamics of speciation using genomic and ecomorphological data of Stellera chamaejasme *** identified four previously unrecognized cryptic species having indistinct morphological traits and large metapopulation of evolving lineages,suggesting a more recent diversification(~2.67-0.90 Mya),largely influenced by Pleistocene glaciation and biotic *** factors likely influenced allopatric speciation and advocated cyclical warming–cooling episodes along elevational gradients during the *** study refines the evolutionary timeline to be much younger than previously implicated and raises the concern that projected future warming may influence the alpine species diversity,necessitating increased conservation efforts.

关键词： cryptic speciation glacial-interglacial Hengduan Mountains north-south migration Stellera chamaejasme

Organic stoichiometric cocrystals with a subtle balance of charge-transfer degree and molecular stacking towards high-efficiency NIR photothermal conversion

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chinese chemical Letters 2024年第10期35卷 206-212页

作者： Jieqiong xu Wenbin chen Shengkai Li Qian chen Tao Wang Yadong Shi Shengyong Deng Mingde Li Peifa Wei Zhuo chen Institutes of Physical Science and Information Technology Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education Anhui Graphene Engineering Laboratory Anhui University Department of chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province Shantou University Molecular Science and Biomedicine Laboratory (MBL) State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical Engineering College of Biology Aptamer Engineering Center of Hunan Province Hunan University

charge-transfer(cT) stoichiometric cocrystals are promising choice of organic materials for unveiling the structure-property relationship. However, due to the contradiction between large cT degree required for strong NIR absorption and flexible molecular stacking, construction of stoichiomorphism-based cocystals with near-infrared(NIR) photothermal property remains challenging. Herein, the first example of stoichiomorphism-based photothermal cocrystals were accomplished through the adaptive assembly of 3,3,5,5-tetramethylbenzidine(TMB) donor and 1,2,4,5-tetracyanobenzene(TcNB) acceptor. The selective cocrystallization could be controlled by varying the donor-acceptor stoichiometries via a surfactantassisted method, resulting in two cocrystals with 1:1(T1c1) and 1:2(T2c1) stoichiometries. The absorbance intensity of T1c1 at 808 nm was nearly twice that of T2c1, while the photothermal conversion efficiency(PcE) of the former was 60.3% ± 0.6%, approximately 80% of that for the latter(75.5% ± 2.6%),which might be caused by the different intermolecular interactions in distinct molecular stacking patterns. Notably, both excellent PcEs of stoichiometric cocrystals were attributed to the nonradiative transition process, including internal conversion and charge dissociation processes, as elucidated by femtosecond transient absorption spectroscopy measurements. Furthermore, T1c1 was used as an NIR heater for preparing agarose-based photothermal hydrogel, showing great potential for light-controlled in-situ gelation. This strategy of balancing the cT degree and molecular packing orientation not only uncovered the relationship between stoichiometric stacking and photothermal property, but also provided an opportunity to develop advanced organic optoelectronic materials.

关键词： charge-transfer cocrystal crystal growth In-situ gelation Photothermal conversion Stoichiometric stacking

Numerical Simulation of the Settling Flux of Biodeposition in a Bay with cage culture Through Similarity Theory and a Simplified Pollution Source

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Journal of Ocean University of china 2024年第1期23卷 247-254页

作者： LIU Yao chen Yifan GE changzi Marine college Shandong UniversityWeihai 264209China

The settling flux of biodeposition affects the environmental quality of cage culture areas and determines their environmental carrying *** and effective simulation of the settling flux of biodeposition is extremely important for determining the spatial distribution of ***,biodeposition in cage culture areas without specific emission rules can be simplified as point source *** is a fluid simulation software that can simulate the dispersion of particulate matter simply and *** on the simplification of pollution sources and bays,the settling flux of biodeposition can be easily and effectively simulated by Fluent fluid *** the present work,the feasibility of this method was evaluated by simulation of the settling flux of biodeposition in Maniao Bay,Hainan Province,china,and 20 sampling sites were selected for determining the settling *** sampling sites P1,P2,P3,P4,P5,Z1,Z2,Z3,Z4,A1,A2,A3,A4,B1,B2,c1,c2,c3 and c4,the measured settling fluxes of biodeposition were 26.02,15.78,10.77,58.16,6.57,72.17,12.37,12.11,106.64,150.96,22.59,11.41,18.03,7.90,19.23,7.06,11.84,5.19 and 2.57 g d^(−1)m^(−2),*** simulated settling fluxes of biodeposition at the corresponding sites were 16.03,23.98,8.87,46.90,4.52,104.77,16.03,8.35,180.83,213.06,39.10,17.47,20.98,9.78,23.25,7.84,15.90,6.06 and 1.65 g d^(−1)m^(−2),*** was a positive correlation between the simulated settling fluxes and measured ones(R=0.94,P=2.22×10^(−9)ch implies that the spatial differentiation of biodeposition flux was well ***,the posterior difference ratio of the simulation was 0.38,and the small error probability was 0.94,which means that the simulated results reached an acceptable level from the perspective of relative ***,if nonpoint source pollution is simplified to point source pollution and open waters are simplified based on similarity theory,the setting flux of biodeposition i

关键词： fluent fluid simulation software pollution source simplification posterior difference ratio similarity theory Spear-man correlation

Record-breaking High-temperature Outlook for 2023: An Assessment Based on the china Global Merged Temperature(cMST) Dataset

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Advances in Atmospheric Sciences 2024年第2期41卷 369-376页

作者： Zichen LI Qingxiang LI Tianyi chen School of Atmospheric Sciences and Guangdong Province Key Laboratory for climate change and Natural Disasters SUN Yat-Sen UniversityZhuhai 519082China Research center for Ecology and Environment of central Asia Chinese Academy of SciencesUrumqi 830011China Southern Laboratory of Ocean Science and Engineering(Guangdong Zhuhai) Zhuhai 519082China

According to the latest version(version 2.0) of the china global Merged Surface Temperature(cMST2.0) dataset, the global mean surface temperature(GMST) in the first half of 2023 reached its third warmest value since the period of instrumental observation began, being only slightly lower than the values recorded in 2016 and 2020, and historically record-breaking GMST emerged from May to July 2023. Further analysis also indicates that if the surface temperature in the last five months of 2023 approaches the average level of the past five years, the annual average surface temperature anomaly in 2023 of approximately 1.26°c will break the previous highest surface temperature, which was recorded in 2016of approximately 1.25°c(both values relative to the global pre-industrialization period, i.e., the average value from 1850 to1900). With El Ni?o triggering a record-breaking hottest July, record-breaking average annual temperatures will most likely become a reality in 2023.

关键词： cMST2.0 global mean surface temperature record-breaking temperature El Ni?o

Nb-and Ta-doped(Hf,Zr,Ti)c multicomponent carbides with enhanced oxidation resistance at 2500℃

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Journal of Advanced ceramics 2024年第3期13卷 332-344页

作者： Shiyan chen Jinming Wang Zhaoke chen Weilong Song Yi Zeng xingchao Li Tongqi Li xiang xiong State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Aerospace Research Institute of Materials&Processing Technology China Academy of Launch Vehicle TechnologyBeijing 100076China

Enhancing oxidation resistance of multicomponent carbides above 2000℃is critical for their thermal protection *** this purpose,novel Nb-and Ta-doped(Hf,Zr,Ti)c multicomponent carbides were designed to improve their oxidation resistance at 2500℃.The results demonstrated that Nb and Ta doping reduced the oxidation rate constant by 16.67%and 25.17%,respectively,thereby significantly improving the oxidation resistance of(Hf,Zr,Ti)*** enhancement was attributed to the changes in ox.carbide composition and distribution within the oxide layer by adding Nb and *** to the different oxidation tendencies of the constituent elements,a distinctive structure was formed in which(Hf,Zr)O_(2)served as a skeleton,and various ox.carbides were dispersed throughout the oxide *** doped Nb and Ta were retained within ox.carbides,retarding the diffusion of oxygen into the *** importantly,the addition of Nb and Ta reduced the size of ox.carbides,decreasing both size and quantity of the pores in the oxide layer and facilitating the formation of a more effective oxygen barrier.

关键词： (Hf,Zr,Ti)c oxidation behaviour ultra-high-temperature oxidation Nb and Ta doping ox.carbides

Understanding the cooperative effects in the catalysis of homodimeric fluoroacetate dehalogenase

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Science china chemistry 2024年第7期67卷 2382-2391页

作者： Ke-Wei chen Jia-Nan chen Jun Zhang chao Wang Tian-Yu Sun Yun-Dong Wu Key Laboratory of computational chemistry and Drug Design State Key Laboratory of Chemical OncogenomicSchool of Chemical Biology and BiotechnologyPeking University Shenzhen Graduate SchoolShenzhen 518055China Institute of chemical Biology Shenzhen Bay LaboratoryShenzhen 518132China college of chemistry and Molecular Engineering Peking UniversityBeijing 100871China changping Laboratory Beijing 102200China

Fluoroacetate dehalogenases(FAcD),a homodimeric enzyme,catalyzes the conversion of fluoroacetic acid to glycolic acid(GoA).It has been proved that the enzyme has a half-of-the-site ***,its catalytic(c)subunit converts the first substrate to a covalent intermediate;then,the non-catalytic(Nc)subunit binds a second substrate and promotes the conversion of the intermediate in the c subunit into the final *** the release of the product,the c subunit becomes the Nc subunit,and the previous Nc subunit becomes the c *** elucidate the detailed mechanism behind this cooperative catalysis,we have conducted microsecond-scale MD simulations along the reaction *** simulations indicate that the substrate in the Nc subunit induces W185 and Y141 adopting an open conformation in the c *** opening of W185(c)facilitates the entry of catalytic water,enhancing the catalytic activity for product formation,while the opening of Y141(c)creates an unfavorable environment for product binding,promoting its *** interaction network analysis reveals that the substrate in the Nc subunit can induce conformational changes through a conserved water chain at the interface.

关键词： enzyme catalysis molecular dynamics cooperative effect pre-reaction state

Recent advances of versatile reagents as controllable building blocks in organic synthesis

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chinese chemical Letters 2024年第2期35卷 24-43页

作者： Shaomin chen Luigi Vaccaro Yanlong Gu Key Laboratory of Material chemistry for Energy conversion and Storage Ministry of EducationHubei Key Laboratory of Material Chemistry and Service FailureSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan 430074China Laboratory of Green S.O.c. Dipartimento di ChimicaBiologia e BiotecnologieUniversità degli Studi di PerugiaVia Elce di Sotto 8Perugia 06123Italy School of chemistry and chemical Engineering The Key Laboratory for Green Processing of Chemical Engineering of Xinjiang BingtuanShihezi UniversityShihezi 832004China

Diversity-oriented synthesis is a powerful and interesting synthetic tool for the rapid construction of structurally complex and privileged scaffolds from readily accessible starting *** date,diversity-oriented synthesis mostly relies on the employment of versatile *** reagents can be regulated as controllable and flexible building blocks for multipurpose *** the past decade,a variety of multifunctional reagents have been ***,most versatile reagents usually need multi-step synthesis,thus restricting their wide application to a large *** terms of the practicalities and universalities,we prefer to pay more attention to the utilization of simple and practical versatile reagents with multiple reactivities,mainly including atropaldehyde acetals,aryl methyl ketones,vinylene carbonate,vinyl azides,aryldiazonium salts,rongalite,halodifluoromethyl *** importantly,these versatile reagents can also play different roles simultaneously in the same reaction,in which their different reactivities are converged into the final target *** strategy can not only offer more possibilities for the synthesis of several active pharmaceutical ingredients,but also minimize the occurrence of some side reactions by lessening the varieties of ***,a perspective is given at the end of this review.

关键词： Versatile reagents Divergent synthesis Dual synthons Bond cleavage Tandem reactions

Elevational patterns of warming effects on plant community and topsoil properties: focus on subalpine meadows ecosystem

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Journal of Mountain Science 2024年第1期21卷 146-159页

作者： HAO Aihua LUO Zhengming chen xiaojiang Department of Geography Xinzhou Normal UniversityXinzhou 034000China Department of Biological Sciences Xinzhou Normal UniversityXinzhou 034000China

climate warming profoundly affects plant biodiversity, community productivity, and soil properties in alpine and subalpine grassland ecosystems. However, these effects are poorly understood across elevational gradients in subalpine meadow ecosystems. To reveal the elevational patterns of warming effects on plant biodiversity, community structure, productivity, and soil properties, we conducted a warming experiment using open-top chambers from August 2019 to August 2022 at high(2764 m a. s. l.), medium(2631 m a. s. l.), and low(2544 m a. s. l.) elevational gradients on a subalpine meadow slope of Mount Wutai, Northern china. Our results showed that three years of warming significantly increased topsoil temperature but significantly decreased topsoil moisture at all elevations(Pcentage of increasing temperature and decreasing moisture both gradually raised with elevation lifting. Warming-induced decreasing proportions of soil organic carbon(SOc, by 19.24%), and total nitrogen(TN, by 24.56%) were the greatest at high elevational gradients. Experimental warming did not affect topsoil c: N, p H, NO_(3)^(-)-N, or NH_(4)^(+)-N at the three elevational gradients. Warming significantly increased species richness(Px(Pcantly decreased belowground biomass(Pcm at three elevational gradients. Warming caused significant increases in the aboveground biomass in the three elevational plots. Warming significantly increased the aboveground biomass of graminoids in medium(by 92.47%) and low(by 98.25%) elevational gradients, that of sedges in high(by 72.44%) and medium(by 57.16%) elevational plots, and that of forbs in high(by 75.88%), medium(by 34.38%), and low(by 74.95%) elevational plots. Species richness had significant linear correlations with SOc, TN, and c: N(Pcant nonlinear responses to soil temperature and soil moisture in the warmed treatm

关键词： Warming effect Plant diversity pattern community structure change Elevation gradient Alpine meadow ecosystem Mount Wutai

Hydrogen-rich water alleviates constipation by attenuating oxidative stress through the sirtuin1/nuclear factor-erythroid-2-related factor 2/heme oxygenase-1 signaling pathway

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World Journal of Gastroenterology 2024年第20期30卷 2709-2725页

作者： Kai-Di chen Kui-Ling Wang chen chen Yi-Jia Zhu Wen-Wen Tang Yu-Ji Wang Ze-Peng chen Lin-Hai He Yu-Gen chen Wei Zhang Jiangsu Province Hospital of chinese Medicine The Affiliated Hospital of Nanjing University of Chinese MedicineNanjing 210029Jiangsu ProvinceChina The No.1 clinical Medical college Nanjing University of Chinese MedicineNanjing 210029Jiangsu ProvinceChina Department of colorectal Surgery Jiangsu Province Hospital of Chinese MedicineThe Affiliated Hospital of Nanjing University of Chinese MedicineNanjing 210029Jiangsu ProvinceChina Jiangsu Province Key Laboratory of Tumor Systems Biology and chinese Medicine The Affiliated Hospital of Nanjing University of Chinese MedicineNanjing 210029Jiangsu ProvinceChina Jiangsu collaborative Innovation center of chinese Medicine in Prevention and Treatment of Tumor The Affiliated Hospital of Nanjing University of Chinese MedicineNanjing 210029Jiangsu ProvinceChina

BAcKGROUND constipation,a highly prevalent functional gastrointestinal disorder,induces a significant burden on the quality of patients'life and is associated with substantial healthcare ***,identifying efficient therapeutic modalities for constipation is of paramount *** stress is a pivotal contributor to colonic dysmotility and is the underlying pathology responsible for constipation ***,we postulate that hydrogen therapy,an emerging and promising intervention,can serve as a safe and efficacious treatment for *** To determine whether hydrogen-rich water(HRW)alleviates constipation and its potential *** constipation models were established by orally loperamide to Sprague-Dawley *** freely consumed HRW,and were recorded their 24 h total stool weight,fecal water content,and charcoal propulsion *** samples were subjected to 16S rDNA gene *** non-targeted metabolomic analysis,malondialdehyde,and superoxide dismutase levels were *** tissues were stained with hematoxylin and eosin,Alcian blue-periodic acid-Schiff,reactive oxygen species(ROS)immunofluorescence,and immunohistochemistry for cell growth factor receptor kit(c-kit),PGP 9.5,sirtuin1(SIRT1),nuclear factor-erythroid-2-related factor 2(Nrf2),and heme oxygenase-1(HO-1).Quantitative real-time PcR and western blot analysis were conducted to determine the expression level of SIRT1,Nrf2 and HO-1.A rescue experiment was conducted by intraperitoneally injecting the SIRT1 inhibitor,Ex527,into constipated ***460 cells were induced with H2O2 and treated with the metabolites to evaluate ROS and SIRT1 *** HRW alleviated constipation symptoms by improving the total amount of stool over 24 h,fecal water content,charcoal propulsion rate,thickness of the intestinal mucus layer,c-kit expression,and the number of intestinal *** modulated intestinal microbiota imbalance and abnormaliti

关键词： Hydrogen-rich water constipation Sirtuin1 Oxidative stress Gut microbiota Serum metabolites