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Methyl Groups Pendant on Triphenylmethane Toward Modulating Thermal Stability and Dielectric Properties of the Crosslinkable Fluorinated Polyimide Films with High Transparency

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Chinese Journal of Polymer Science 2025年第2期43卷 316-327页

作者： Wen Yang Liang Yuan Kai Gong Ruo-han Zhang Lan Lei Hui Li School of Chemistry and Chemical Engineering Shandong Key Laboratory of Fluorine Chemistry and Chemical Engineering MaterialsUniversity of JinanJinan250022China School of Materials Science and Engineering Tianjin Key Laboratory of Composite and Functional MaterialsTianjin UniversityTianjin300350China

It is urgent to develop high-performance polyimide(PI)films that simultaneously exhibit high transparency,exceptional thermal stability,mechanical robustness,and low dielectric to fulfil the requirements of flexible display ***,a series of fluorinated polyimide films(FPIs)were fabricated by the condensation of 5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione)(6FDA)and the fluorinated triphenylmethane diamine monomer(EDA,MEDA and DMEDA)with heat-crosslinkable tetrafluorostyrene side groups,which was incorporated by different numbers of methyl groups pendant in the ortho position of amino ***,the FPI films underwent heating to produce crosslinking FPIs(C-FPIs)through the self-crosslinking of double bonds in the *** transparency,solvent resistance,thermal stability,mechanical robustness and dielectric properties of FPI and C-FPI films can be tuned by the number of methyl groups and crosslinking,which were deeply investigated by virtue of molecular dynamics(MD)simulations and density functional theory(DFT).As a result,all the films exhibited exceptional optically colorless and transparent,with transmittance in the visible region of 450-700 nm exceeding 79.9%,and the cut-off wavelengths(λ_(off))were nearly 350 *** thermal decomposition temperatures at 5% weight loss(T_(d5%))for all samples exceeded 504℃.These films exhibited a wide range of tunable tensile strength(46.5-75.1 MPa).Significantly,they showed exceptional dielectric properties with the dielectric constant of 2.3-2.5 at full frequency(10^(7)-20 Hz).This study not only highlights the relationship between the polymer molecular structure and properties,but offer insights for balancing optical transparency,heat resistance and low dielectric constant in PI films.

关键词： Crosslinkable fluorinated polyimide Methyl group Triphenylmethane Transparency Thermal stability Low dielectric constant

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Total synthesis of(+)-taberdicatine B and(+)-tabernabovine B

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Chinese Chemical Letters 2025年第2期36卷 349-353页

作者： Tengfei Xuan Xinyu Zhang Wei han Yidong Huang Weiwu Ren Molecular Synthesis Center&Key Laboratory of Marine Drugs Chinese Ministry of EducationSchool of Medicine and PharmacyOcean University of China Laboratory for Marine Drugs and Bioproducts Laoshan Laboratory

The first total synthesis of(+)-taberdicatine B and(+)-tabernabovine B has been accomplished in 10steps with 26.9% overall yield and 15 steps with 7.3% overall yield, respectively. The prominent features of this efficient synthetic strategy include the following:(1)(+)-Taberdicatine B and(+)-tabernabovine B were accessed from common advanced intermediates by varying the substituents;(2) A one-pot asymmetric bromocyclization/hydrolysis was explored to assemble HPI skeleton;(3) Dieckmann condensation to form β-keto ester for the assembly of seven-membered ring;(4) An ester reduction/amide semireduction/cyclization sequence was applied to form the cage-like framework.

关键词： Asymmetric dearomatization Hexahydropyrrolo[2,3-b]indole Taberdicatine B Tabernabovine B Total synthesis

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Synthesis of ordered mesoporous crystalline boron phosphate scaffold with double diamond surface structure

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Science China Chemistry 2025年第2期68卷 590-600页

作者： Chao Wang Wen-Duo Lu Jiao Wang Shunai Che An-Hui Lu Lu han School of Chemical Science and Engineering Tongji UniversityShanghai 200092China State Key Laboratory of Fine Chemicals Liaoning Key Laboratory for Catalytic Conversion of Carbon ResourcesSchool of Chemical EngineeringDalian University of TechnologyDalian 116024China School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative MoleculesState Key Laboratory of Metal Matrix CompositesShanghai Key Laboratory for Molecular Engineering of Chiral DrugsShanghai Jiao Tong UniversityShanghai 200240China

Ordered mesoporous materials have received great attention due to their well-defined pore structures and potential applications in catalysis,adsorption,separation,drug delivery,*** various compositions of mesoporous solids have been successfully prepared,the preparation of crystalline non-metallic oxyacid salts with ordered mesoporosity remains a major ***,we report the synthesis of a mesoporous solid acid crystalline boron phosphate(BPO_(4))catalyst with a bicontinuous shifted double diamond(SDD)hyperbolic surface *** BPO_(4) scaffold was obtained by synergistic selfassembly in a mixed solvent of water and tetrahydrofuran using the diblock copolymer poly(ethylene oxide)-block-polystyrene as template and phosphoric acid and orthoboric acid as inorganic *** structure consists of two sets of diamond networks adjacent to each other with a mesostructural scale tetragonal symmetry(space group I4_(1)/amd)with unit cell parameters of a=80 nm and c=113 nm,which affords the scaffold a specific surface area of 44 m^(2)/*** a solid acid catalytic material,the SDD BPO_(4) scaffold exhibited excellent catalytic activity at room temperature with a conversion of furfural to 2-(dimethoxymethyl)furan over 70%and can be reused after recovery without serious loss of *** the propane oxidative dehydrogenation reaction,SDD BPO_(4) demonstrated high olefin productivity and selectivity while maintaining high reaction *** study provides ideas for the preparation of ordered mesoporous crystalline catalytic materials and demonstrates their potential for practical applications.

关键词： boron phosphate mesoporous material self-assembly block copolymer catalyst

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Exposure of individuals aged 18-44 years to personal care products in Beijing,China:Exposure profiles,possible influencing factors,and risk assessment

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Journal of Environmental Sciences 2025年第2期148卷 691-701页

作者： Xu Zhang Linxue han Qi Sun Xiaochen Wang Xiaojian Hu Xiao Lin Ying Zhu China CDC Key Laboratory of Environment and Population Health National Institute of Environmental HealthChinese Center for Disease Control and PreventionBeijing 100021China The Bureau for Health Inspection and Supervision of Haidian District Beijing 100037China

Personal care products(PCPs)are a class of emerging pollutants that have attracted public concern owing to their harmful effects on humans and the *** data is valuable for insight the levels of PCPs in the human body and can be crucial for identifying potential health *** gain a better understanding of timely exposure profiles and health risk of reproductive-age population to PCPs,we determined six parabens,six benzophenone-type ultraviolet filters,and three disinfectants in 256 urine samples collected from young adults aged 18-44 years in Beijing,*** urinary levels of benzophenone-3(BP-3)and 4-hydroxybenzophenone(4-OHBP)were significantly higher in summer compared to winter,suggesting these compounds have different seasonal usage ***,the total concentration of 15 PCPs in female was 430 ng/mL,approximately two times higher than that in male.P-chloro-m-xylenol(PCMX),as a new type of antibacterial agent,has the greatest level among all target analytes,indicating the increasingly use of this antibacterial alternative *** potential influencing factors that lead to the elevated exposure level of PCPs were *** 19%of the target population had a high hazard index value(greater than 1)which was attributed to exposure to propyl paraben(PrP),benzophenone-1(BP-1),BP-3 and PCMX,indicating that PCPs may pose a relatively high exposure risk at environmental levels that should be a cause for concern.

关键词： Personal care products Hazard quotient Risk assessment Exposure patterns Urine

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Potential role of tanycyte-derived neurogenesis in Alzheimer's disease

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Neural Regeneration Research 2025年第6期20卷 1599-1612页

作者： Guibo Qi han Tang Jianian Hu Siying Kang Song Qin Department of Anatomy Histologyand EmbryologySchool of Basic Medical SciencesFudan UniversityShanghaiChina State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science Fudan UniversityShanghaiChina

Tanycytes, specialized ependymal cells located in the hypothalamus, play a crucial role in the generation of new neurons that contribute to the neural circuits responsible for regulating the systemic energy balance. The precise coordination of the gene networks controlling neurogenesis in naive and mature tanycytes is essential for maintaining homeostasis in adulthood. However, our understanding of the molecular mechanisms and signaling pathways that govern the proliferation and differentiation of tanycytes into neurons remains limited. This article aims to review the recent advancements in research into the mechanisms and functions of tanycyte-derived neurogenesis. Studies employing lineage-tracing techniques have revealed that the neurogenesis specifically originating from tanycytes in the hypothalamus has a compensatory role in neuronal loss and helps maintain energy homeostasis during metabolic diseases. Intriguingly,metabolic disorders are considered early biomarkers of Alzheimer's disease. Furthermore,the neurogenic potential of tanycytes and the state of newborn neurons derived from tanycytes heavily depend on the maintenance of mild microenvironments, which may be disrupted in Alzheimer's disease due to the impaired blood–brain barrier ***, the specific alterations and regulatory mechanisms governing tanycyte-derived neurogenesis in Alzheimer's disease remain unclear. Accumulating evidence suggests that tanycyte-derived neurogenesis might be impaired in Alzheimer's disease, exacerbating neurodegeneration. Confirming this hypothesis, however, poses a challenge because of the lack of long-term tracing and nucleus-specific analyses of newborn neurons in the hypothalamus of patients with Alzheimer's disease. Further research into the molecular mechanisms underlying tanycyte-derived neurogenesis holds promise for identifying small molecules capable of restoring tanycyte proliferation in neurodegenerative diseases. This line of investigation could pro

关键词： Alzheimer's disease blood–brain barrier ependymoglial cells hypothalamus metabolic diseases neural stem cells neurogenesis neuroinflammatory diseases neurons tanycyte

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Deep eutectic solvents for separation and purification applications in critical metal metallurgy:Recent advances and perspectives

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 1-19页

作者： Shuo Chen Shengpeng Su Yanfang Huang Bingbing Liu Hu Sun Shuzhen Yang Guihong han School of Chemical Engineering Zhengzhou UniversityZhengzhou 450001China Zhongyuan Critical Metals Laboratory Henan ProvinceZhengzhou 450001China

Solvent extraction,a separation and purification technology,is crucial in critical metal *** solvents commonly used in solvent extraction exhibit disadvantages,such as high volatility,high toxicity,and flammability,causing a spectrum of hazards to human health and environmental *** solvents have been recognized as potential alternatives to these harmful organic *** the past two decades,several neoteric solvents have been proposed,including ionic liquids(ILs)and deep eutectic solvents(DESs).DESs have gradually become the focus of green solvents owing to several advantages,namely,low toxicity,degradability,and low *** this critical review,their classification,formation mechanisms,preparation methods,characterization technologies,and special physicochemical properties based on the most recent advancements in research have been systematically ***,the major separation and purification applications of DESs in critical metal metallurgy were comprehensively ***,future opportunities and challenges of DESs were explored in the current research *** conclusion,this review provides valuable insights for improving our overall understanding of DESs,and it holds important potential for expanding separation and purification applications in critical metal metallurgy.

关键词： deep eutectic solvents preparations properties separation and purification critical metal metallurgy

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Deciphering fungal metabolon coupling tandem inverse-electrondemand Diels-Alder reaction and semipinacol rearrangement for the biosynthesis of spiro polycyclic alkaloids

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Science China Chemistry 2025年第1期68卷 288-296页

作者： Shuai Liu Wen-Qiang Xu Ying-Tong Di Man-Cheng Tang Ding-Kang Chen Ming-Ming Cao Yao-Wen chang Hong-Yu Tang Chun-Mao Yuan Jun-Bo Yang Zhi-Li Zuo han Guo Zi-Fei Xu Ying Zeng Yun-Dong Wu Xiao-Jiang Hao Key Laboratory of Phytochemistry and Natural Medicines(Chinese Academy of Sciences) Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China Lab of Computational Chemistry and Drug Design State Key Laboratory of Chemical OncogenomicsPeking University Shenzhen Graduate SchoolShenzhen 518055China Shenzhen Bay Laboratory Shenzhen 518055China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Microbial Metabolism School of Life Sciences&BiotechnologyShanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Functions and Applications of Medicinal Plants Guizhou Medical UniversityGuiyang 550014China Molecular Biology Experimental Center Germplasm Bank of Wild Species in Southwest ChinaKunming Institute of BotanyChinese Academy of SciencesKunming 650201China Yunnan Key Laboratory for Wild Plant Resources Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China Research Unit of Chemical Biology of Natural Anti-Virus Products Chinese Academy of Medical SciencesBeijing 100730China

In the intricate process of natural product biosynthesis,a metabolon can enhance metabolic flux by associating sequential enzymes.A fungal metabolon,comprising of flavin-dependent monooxygenase Spe F and P450 monooxygenase Spe G,is identified in the biosynthesis of spiro polycyclic alkaloids(+)-notoamide B and its diastereomer(+)-versicolamide *** notoamide E as a substance,Spe F/Spe G metabolon can control the stereoselectivity of its 2,3-epoxidation,followed by hydrogen atom ion at C-17 to generate reactive epoxide tau-m A with dienyl iminium ***,(+)-notoamide B and(+)-versicolamide B are produced via tandem nonenzymatic inverse-electron-demand Diels-Alder reaction and semipinacol *** provides the first example of metabolon in the biosynthesis of spiro-prenylated indole alkaloids.

关键词： metabolon Diels-Alder reaction semipinacol rearrangement biosynthesis notoamides spiro polycyclic alkaloids

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精梳机钳板机构接触碰撞动力学建模与仿真

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纺织学报 2025年第1期46卷 179-186页

作者：畅博彦韩芳孝周杨关鑫天津工业大学机械工程学院天津300387 天津工业大学天津市现代机电装备技术重点实验室天津300387

高速、高产、优质是新一代国产棉纺精梳机的发展目标,而当前精梳机存在的主要问题之一是高速运行时钳板机构产生的冲击严重限制了精梳机转速的提升,针对该问题进行动力学研究以提升钳板机构稳定性,达到推进精梳机高速化的目的。首先,以... 详细信息

高速、高产、优质是新一代国产棉纺精梳机的发展目标,而当前精梳机存在的主要问题之一是高速运行时钳板机构产生的冲击严重限制了精梳机转速的提升,针对该问题进行动力学研究以提升钳板机构稳定性,达到推进精梳机高速化的目的。首先,以中支点式钳板机构为研究对象,基于接触碰撞理论建立钳板在接触和分离瞬时的冲击力计算模型,结合Lagrange方程对钳板机构进行接触碰撞动力学建模。其次,运用MatLab对所建动力学模型进行数值计算仿真,结合三维虚拟样机仿真验证模型的正确性和有效性。最后,分析钳板机构工况参数和加压弹簧刚度对冲击运动和冲击接触应力的影响规律。结果表明:钳口与牵吊杆处的最大接触应力远大于稳定接触应力,且回弹量和回弹时间会随锡林轴转速的提高而增大,随加压弹簧刚度的增大而减小。

关键词：精梳机钳板机构接触碰撞力 Lagrange方程动力学

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Independent and interactive effects of N and P additions on foliar P fractions in evergreen forests of southern China

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FOREST ECOSYSTEMS 2025年第1期12卷 66-73页

作者： Meng, Qingquan Shi, Zhijuan Yan, Zhengbing Lambers, hans Luo, Yan han, Wenxuan China Agr Univ Minist Educ Coll Resources & Environm Sci Key Lab Plant Soil Interact Beijing 100193 Peoples R China Chinese Acad Sci Inst Bot Beijing 100093 Peoples R China Univ Western Australia Sch Biol Sci Perth WA 6009 Australia Xinjiang Univ Educ Minist Coll Ecol & Environm Key Lab Oasis Ecol Urumqi 830017 Peoples R China

Fertilization or atmospheric deposition of nitrogen (N) and phosphorus (P) to terrestrial ecosystems can alter soil N (P) availability and the nature of nutrient limitation for plant growth. changing the allocation of leaf P fractions is potentially an adaptive strategy for plants to cope with soil N (P) availability and nutrient-limiting conditions. However, the impact of the interactions between imbalanced anthropogenic N and P inputs on the concentrations and allocation proportions of leaf P fractions in forest woody plants remains elusive. We conducted a meta- analysis of data about the concentrations and allocation proportions of leaf P fractions, specifically associated with individual and combined additions of N and P in evergreen forests, the dominant vegetation type in southern China where the primary productivity is usually considered limited by P. This assessment allowed us to quantitatively evaluate the effects of N and P additions alone and interactively on leaf P allocation and use strategies. Nitrogen addition (exacerbating P limitation) reduced the concentrations of leaf total P and different leaf P fractions. Nitrogen addition reduced the allocation to leaf metabolic P but increased the allocation to other fractions, while P addition showed opposite trends. The simultaneous additions of N and P showed an antagonistic (mutual suppression) effect on the concentrations of leaf P fractions, but an additive (summary) effect on the allocation proportions of leaf P fractions. These results highlight the importance of strategies of leaf P fraction allocation in forest plants under changes in environmental nutrient availability. Importantly, our study identified critical interactions associated with combined N and P inputs that affect leaf P fractions, thus aiding in predicting plant acclimation strategies in the context of intensifying and imbalanced anthropogenic nutrient inputs.

关键词： Anthropogenic nutrient inputs Individual and combined effects Interactive effects Leaf phosphorus fractions Nitrogen and phosphorus additions Nutrient-utilization strategies Woody plants

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Charge polarity inversion and zincophilicity improvement for chitosan separator towards durable aqueous zinc-ion batteries

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Journal of Energy Chemistry 2025年第2期101卷 110-119页

作者： Jiaqi Yu Bo Liu Hong Ma Zehua Fan Xiang han Qinghua Tian Jizhang Chen Co-Innovation Center of Efficient Processing and Utilization of Forest Resources College of Materials Science and Engineering Nanjing Forestry University College of Mathematics and Physics Jinggangshan University Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province School of Chemistry and Chemical Engineering Zhejiang Sci-Tech University

Aqueous zinc-ion batteries encounter enormous challenges such as Zn dendrites and parasitic *** modification is a highly effective strategy to address these *** the advantages of low cost,nontoxicity,biodegradability,good film-forming ability,superior hydro phi licity,and rich functional groups,chitosan is an ideal matrix for constructing ***,the presence of positive charges within chitosan in weakly acidic electrolytes is unfavorable for dendrite ***,Schiff base reaction is introduced to modify chitosan matrix,transforming its charge polarity from positive to ***,NbN with excellent zincophilicity is coated onto chitosan matrix,forming a Janus separator with low thickness of 19 μm and considerably improved mechanical *** resultant separator can promote the transport of Zn2+ions while triggering a repulsive shielding effect against anions,therefore dramatically enhancing Zn2+ion transfer number from 0.28 to *** separator can also facilitate desolvation process,improve exchange current density,restrict two-dimensional Zn2+ion diffusion,and enhance electrochemical kinetics,contributing to significantly inhibited dendrite growth,by-product formation,and hydrogen ***,stable and reversible Zn stripping/plating process is enabled for over 2500 h at 2 mA cm-2and 2 mAh *** great rate capability and excellent cyclability can be achieved for full batteries even under harsh *** work provides new insights into separator design for Zn-based batteries.

关键词： Aqueous zinc-ion batteries Charge polarity regulation Chitosan utilization Dendrite inhibition Separator modification

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