检索结果-南通市图书馆

Effects of drought on non-structural carbohydrates and C,N,and P stoichiometric characteristics of Pinus yunnanensis seedlings

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2024年第1期35卷 90-102页

作者： Zhijuan Zhao Lina Wang Yuanxi liu Jianli Sun Jiandong xiao qiong Dong Lianfang Li Wanjie Zhang Chao Wang Junwen Wu College of Forestry Southwest Forestry UniversityKunming 650224YunnanPeople’s Republic of China

To study non-structural carbohydrate character-istics and nutrient utilization strategies of Pinus yunnanen-sis under continuous drought conditions,2-year-old seed-lings were planted in pots with appropriate water,light and moderate and severe drought treatments[(80±5),(65±5),(50±5),and(35±5)%of field water-holding capacity].Non-structural carbohydrates,carbon(C),nitrogen(N),and phosphorus(P)concentrations were measured in each plant *** results show that:(1)With increasing drought,non-structural carbohydrates gradually increased in leaves,stems,and coarse roots,while gradually decreased in fine roots;(2)C concentrations of all were relatively stable under different stress *** utilization of each component increased under light and moderate drought conditions,while N and P utilization efficiency of each plant component decreased under severe *** was mainly restricted by N,first decreasing and then increasing with increased drought;(3)There was a correlation between the levels of non-structural carbohydrates and C,N,and P in each *** in N concentration affected the interconversion between soluble sugar and starch,which play a regulatory role in the fluctuation of the concentration of non-structural carbohydrates;and,(4)Plasticity analysis showed that *** seedlings responded to drought mainly by altering starch concentration,the ratio of soluble sugar to starch in leaves and stems,and further by alter-ing N and P utilization ***,these results suggest that the physiological activities of all organs of *** seedlings are restricted under drought and that trade-offs exist between different physiological indicators and *** findings are helpful in understanding non-structural carbohydrate and nutrient adaptation mechanisms under drought in *** seedlings.

关键词： Pinus yunnanensis seedlings Drought Non-structural carbohydrates C,N,P stoichiometric characteristics

Bioinspired zinc-mediated umpolung thiolation of alkyl electrophiles: reaction development, scope and mechanism

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第3期67卷 898-907页

作者： Yuenian Xu Yan Zhang Yong liu Wen-Wu Sun Jie Huang Hui He Yingjie Wu Wen liu Shao-Fei Ni Xu-qiong xiao Xinxin Shao College of Material Chemistry and Chemical EngineeringKey Laboratory of Organosilicon Chemistry and Material Technology of Ministry of EducationHangzhou Normal UniversityHangzhou 311121China School of Pharmaceutical Sciences South-Central Minzu UniversityWuhan 430074China Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guang-dong Province Shantou UniversityShantou 515063China

Zinc-promoted umpolung thiolation of alkyl electrophiles with masked sulfur transfer reagents in the absence of nickel or copper catalysis is described. This protocol proceeds via a SET process of Zn to electrophilic sulfur reagent followed by insertion of Zn into disulfide and nucleophilic thiolation, providing straightforward access to a wide range of alkyl sulfides with broad substrate scope. A neutral TMEDA-ligated four-coordinated zinc thiolate with tetrahedra geometry was synthesized, isolated and fully characterized by NMR, IR and X-ray analysis. More importantly, the chemical reactivity of this active intermediate has been investigated, enabling the construction of C-Se, C-Te, Sb-S and Bi-S bonds to prepare valuable sulfur-containing molecules and beyond.

关键词： umpolung thiolation C(sp^(3))-S bond formation masked sulfur reagents reductive coupling

同方期刊数据库

Regulating^(*)COOH intermediate via amino alkylation engineering for exceptionally effective photocatalytic CO_(2) reduction

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第5期92卷 282-291页

作者： Chengcheng Chen Qiaoyu Zhang Fangting liu Zhengguo Zhang qiong liu xiaoming Fang Key Laboratory of Enhanced Heat Transfer and Energy Conservation The Ministry of EducationSchool of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640GuangdongChina Guangdong Provincial Key Laboratory of Chemical Measurement and Emergency Test Technology(China) Institute of AnalysisGuangdong Academy of Sciences(China National Analytical CenterGuangzhou)Guangzhou 510070GuangdongChina Guangdong Engineering Technology Research Center of Efficient Heat Storage and Application South China University of TechnologyGuangzhou 510640GuangdongChina Guangdong Provincial Key Laboratory of Fuel Cell Technology South China University of TechnologyGuangzhou 510640GuangdongChina

Photocatalytic reduction of CO_(2) into fuel represents a promising approach for achieving carbon neutrality,while realizing high selectivity in this process is challenging due to uncontrollable reaction intermediate and retarded desorption of target *** the interface microenvironment of catalysts has been proposed as a strategy to exert a significant influence on reaction outcomes,yet it remains a significant *** this study,amino alkylation was successfully integrated into the melem unit of polymeric carbon nitrides(PCN),which could efficiently drive the photocatalytic CO_(2) *** characterization and theoretical calculations revealed that the introduction of amino alkylation lowers the energy barrier for CO_(2) reduction into^(*)COOH intermediate,transforming the adsorption of^(*)COOH intermediate from the endothermic to an exothermic ***,the as-prepared materials demonstrated outstanding performance in photocatalytic CO_(2) reduction,yielding CO_(2)at a rate of 152.8μmol h^(-1) with a high selectivity of 95.4%and a quantum efficiency of 6.6%.

关键词： Polymeric carbonnitride Regulate intermediate Photocatalytic CO_(2)reduction Amino alkylation ^(*)COOH adsorption

Inflammatory and Immunomodulatory Effects of Tripterygium wilfordii Multiglycoside in Mouse Models of Psoriasis Keratinocytes

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Integrative Medicine 2024年第3期30卷 222-229页

作者： ZHANG Shuo LI Hong-jin YANG Chun-mei liu liu SUN xiao-ying WANG Jiao CHEN Si-ting LU Yi HU Man-qi YAN Ge ZHOU Ya-qiong MIAO xiao LI Xin LI Bin Department of Dermatology Yueyang Hospital of Integrated Traditional Chinese and Western MedicineShanghai University of Traditional Chinese MedicineShanghai200437China Institute of Dermatology Shanghai Academy of Traditional Chinese MedicineShanghai201203China Department of Integrated Traditional Chinese and Western Medicine Shanghai Skin Disease HospitalTongji University School of MedicineShanghai200443China

Objective:To determine the role of Tripterygium wilfordii multiglycoside(TGW) in the treatment of psoriatic dermatitis from a cellular immunological ***:Mouse models of psoriatic dermatitis were established by imiquimod(IMQ).Twelve male BALB/c mice were assigned to MQ or IMQ+TGW groups according to a random number *** changes in vivo were assessed by hematoxylin and eosin *** of immune cells and cytokines in mice,as well as PAM212 cell proliferation in vitro were assessed by flow ***-inflammatory cytokine expression was determined using reverse transcription quantitative polymerase chain ***:TGW significantly ameliorated the severity of IMQ-induced psoriasis-like mouse skin lesions and restrained the activation of CD45^(+)cells,neutrophils and T lymphocytes(all P<0.01).Moreover,TGW significantly attenuated keratinocytes(KCs) proliferation and downregulated the mRNA levels of inflammatory cytokines including interleukin(IL)-17A,IL-23,tumor necrosis factor α,and chemokine(C-X-C motif) ligand 1(P<0.01 or P<0.05).Furthermore,it reduced the number of γδ T17 cells in skin lesion of mice and draining lymph nodes(P<0.01).Conclusions:TGW improved psoriasis-like inflammation by inhibiting KCs proliferation,as well as the associated immune cells and cytokine *** inhibited IL-17 secretion from γδ T cells,which improved the immune-inflammatory microenvironment of psoriasis.

关键词： psoriasis Tripterygium wilfordii multiglycoside γδT cells inflammation Chinese medicine

Current optimization-based control of dual three-phase PMSM for low-frequency temperature swing reduction

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第4期34卷 238-246页

作者： Linlin Lu Xueqing Wang Luhan Jin qiong liu Yun Zhang Yao Mao Key Laboratory of Optical Engineering Chinese Academy of SciencesChengdu 610209China Institute of Optics and Electronics Chinese Academy of SciencesChengdu 610209China University of Chinese Academy of Sciences Beijing 100049China College of Electrical Engineering Sichuan UniversityChengdu 610065China

In this paper,a control scheme based on current optimization is proposed for dual three-phase permanent-magnet synchronous motor(DTP-PMSM)drive to reduce the low-frequency temperature *** reduction of temperature swing can be equivalent to reducing maximum instantaneous phase copper loss in this ***,a two-level optimization aiming at minimizing maximum instantaneous phase copper loss at each electrical angle is ***,the optimization is transformed to a singlelevel optimization by introducing the auxiliary variable for easy *** that singleobjective optimization trades a great total copper loss for a small reduction of maximum phase copper loss,the optimization considering both instantaneous total copper loss and maximum phase copper loss is proposed,which has the same performance of temperature swing reduction but with lower total *** this way,the proposed control scheme can reduce maximum junction temperature by 11%.Both simulation and experimental results are presented to prove the effectiveness and superiority of the proposed control scheme for low-frequency temperature swing reduction.

关键词： Dual three-phase PMSM Low-frequency temperature swing Copper loss Current optimization Connected neutral points

Polymer-to-Monomers Chemically Recyclable Poly(imide-imine)Plastics with Extreme-Condition Resistance and Flame Retardancy

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第10期42卷 1525-1535,I0012页

作者： Zhen-Yu Wang xiao-Kong liu State Key Laboratory of Supramolecular Structure and Materials College of ChemistryJilin UniversityChangchun130012China

Polyimides are a family of high-tech plastics that have irreplaceable applications in the fields of aerospace,defense,and opto-electronics,but polyimides are difficult to be reprocessed and recycled at the end of their service life,resulting in a significant waste of ***,it is of great significance to develop recyclable polyimides with comparable properties to the commercial ***,we report a novel polymer-to-monomers chemically recyclable poly(imide-imine)(PtM-CR-PII)plastic,synthesized by cross-linking the amine-terminated aromatic bisimide monomer and the hexa-vanillin terminated cyclophosphazene monomer via dynamic imine *** PtM-CR-PII plastic exhibits comparable mechanical and thermal properties as well as chemical stability to the commercial *** PtM-CR-PII plastic possesses a high Young’s modulus of≈3.2 GPa and a tensile strength as high as≈108 MPa,which also exhibits high thermal stability with a glass transition temperature of≈220℃.Moreover,the PtM-CR-PII plastic exhibits outstanding waterproofness,acid/alkali-resistance,and solvent-resistance,its appearance and mechanical properties can be well maintained after long-term soaking in water,highly concentrated acid and base,and various organic ***,the cyclophosphazene moieties endow the PtM-CR-PII plastic with excellent flame *** PtM-CR-PII plastic exhibits the highest UL-94 flame-retarding rating of V-0 and a limiting oxygen index(LOI)value of 45.5%.Importantly,the PtM-CR-PII plastic can be depolymerized in an organic solvents-acid mixture medium at room temperature,allowing easy separation and recovery of both monomers in high *** recovered pure monomers can be used to regenerate new PtM-CR-PII plastics,enabling sustainable polymer-monomers-polymer circulation.

关键词： Chemical recyclability Polyimides Polyimines Dynamic imine bonds Mechanical properties Chemical stability

Universal paradigm of ternary metacomposites with tunable epsilon-negative and epsilon-near-zero response for perfect electromagnetic shielding

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第2期43卷 796-809页

作者： Yun-Peng Qu Yun-Lei Zhou Yang Luo Yao liu Jun-Fei Ding Yan-Li Chen Xiu Gong Jing-Liang Yang qiong Peng xiao-Si Qi College of Physics Guizhou UniversityGuiyang550025China Hangzhou Institute of Technology Xidian UniversityHangzhou311231China Department of Materials ETH Zurich8093ZurichSwitzerland Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinan250061China

CaCu_(3)Ti_(4)O_(12)(CCTO)ceramic nanocomposites incorporating graphene–carbon black(GRCB)fillers were fabricated by spark plasma sintering *** percolative effects of conductive GRCB fillers on dielectric response of GRCB/CCTO ternary metacomposites were systematically *** weakly real permittivity(ε′)-negative response(ε′~−1×10^(2))was achieved which originated from weakly low-frequency plasmonic state of free carriers within constructed GRCB *** enhancing three-dimensional GRCB network,the plasma frequency of metacomposites increased while the damping factor ***,theε′-negative values of metacomposites were tuned from−10^(2) to−10^(4) orders of magnitude andε′-near-zero(ENZ)frequencies from~142 to~340 MHz which substantially benefited from the moderate carrier concentration of GRCB dual *** Drude model and equivalent circuit models were adopted to demonstrate dielectric and electrical *** obtained metacomposites show strong EM shielding effect along with enhanced plasmonic oscillation and even better achieving perfect EM shielding effect in ENZ *** work achieves the tunableε′-negative andε′-near-zero response and more importantly clarifies its regulation mechanism in ceramic-based ternary metacomposites,which opens up the possibility of designing high-performance EM shielding materials based on metacomposites.

关键词： Metacomposites Ceramic matrix composites Negative permittivity Epsilon-near-zero Electromagnetic shielding

SOLVING OPTIMIZATION PROBLEMS OVER THE STIEFEL MANIFOLD BY SMOOTH EXACT PENALTY FUNCTIONS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2024年第5期42卷 1246-1276页

作者： Nachuan xiao Xin liu The Institute of Operations Research and Analytics National University of SingaporeSingapore State Key Laboratory of Scientific and Engineering Computing Academy of Mathematics and Systems ScienceChinese Academy of Sciencesand University of Chinese Academy of SciencesChina

In this paper,we present a novel penalty model called ExPen for optimization over the Stiefel *** from existing penalty functions for orthogonality constraints,ExPen adopts a smooth penalty function without using any first-order derivative of the objective *** show that all the first-order stationary points of ExPen with a sufficiently large penalty parameter are either feasible,namely,are the first-order stationary points of the original optimization problem,or far from the Stiefel ***,the original problem and ExPen share the same second-order stationary ***,the exact gradient and Hessian of ExPen are easy to *** a consequence,abundant algorithm resources in unconstrained optimization can be applied straightforwardly to solve ExPen.

关键词： Orthogonality constraint Stiefel manifold Penalty function

NLRP3 and autophagy in retinal ganglion cell inflammation in age-related macular degeneration:potential therapeutic implications

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2024年第8期17卷 1531-1544页

作者： xiao-Li Wang Yun-Xia Gao qiong-Zhen Yuan Ming Zhang Department of Ophthalmology West China HospitalSichuan UniversityChengdu 610041Sichuan ProvinceChina

Retinal degenerative diseases were a large group of diseases characterized by the primary death of retinal ganglion cells(RGCs).Recent studies had shown an interaction between autophagy and nucleotide-binding oligomerization domain-like receptor 3(NLRP3)inflammasomes,which may affect RGCs in retinal degenerative *** NLRP3 inflammasome was a protein complex that,upon activation,produces caspase-1,mediating the apoptosis of retinal cells and promoting the occurrence and development of retinal degenerative *** autophagy could inhibit NLRP3 inflammasome activation,while inhibited autophagy can promote NLRP3 inflammasome activation,which leaded to the accelerated emergence of drusen and lipofuscin deposition under the neurosensory *** activated NLRP3 inflammasome could further inhibit autophagy,thus forming a vicious cycle that accelerated the damage and death of *** review discussed the relationship between NLRP3 inflammasome and autophagy and its effects on RGCs in age-related macular degeneration,providing a new perspective and direction for the treatment of retinal diseases.

关键词： autophagy age-related macular degeneration NLRP3 inflammasome retinal degeneration retinal ganglion cells