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Catalytically generated noncovalent ammonium dienolate:a versatile platform for the development of organocatalytic asymmetric cascade reactions

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Science China Chemistry 2024年第8期67卷 2524-2546页

作者： Jun-Bing Lin Dong-Sheng ji peng-Fei Xu State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical EngineeringLanzhou UniversityLanzhou 730000China Shaanxi Key Laboratory of Chemical Reaction Engineering College of Chemistry and Chemical EngineeringYan’an UniversityYan’an 716000China

Organocatalytic cascade reactions represent a powerful strategy for the rapid construction of complex chiral molecules with multiple stereocenters from simple substrates under mild conditions. The intriguing structural feature and diverse reactivity of catalytically generated dienolate species render them competent and versatile intermediates for the development of practical and valuable cascade reactions. Over the past years, a plethora of innovative and pioneering noncovalent ammonium dienolatemediated cascade reactions have been designed and implemented under the catalysis of chiral organocatalysts, making dienolate activation a general, robust, and complementary method for the functionalization of unsaturated carbonyl compounds and related substances. This review illustrates the recent advances in organocatalytic noncovalent ammonium dienolate-mediated cascade reactions(mainly from 2010 to 2023), including the cascade transformations of ammonium dienolates directly generated from unsaturated ketone/aldehyde, ester/lactone/azlactone, amide/lactam/pyrazolone/oxindole, and alkylidene nitrile compounds. The contents are arranged based on the reaction types of the ammonium dienolates, with an emphasis on cascade 2,5-, 3,5-, and 4,5-difunctionalizations of these intermediates. Furthermore, other cascade reactions involving the 1,3-, 2,3-, and even more complex 3,4,5-reactivities of ammonium dienolates were also discussed. The reaction pathway, reaction stereoinduction, and synthetic applications of the ammonium dienolate-mediated cascade reactions were highlighted throughout the article. As a stimulating and ever-growing research area, the organocatalytic noncovalent ammonium dienolate-mediated cascade reactions are expected to continue demonstrating their magic power for constructing chiral targets in the future and further expanding the boundaries of asymmetric catalysis.

关键词： organocatalysis asymmetric catalysis ammonium dienolate cascade reaction difunctionalization

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Endogenous Trypsin Triggers Free Fluoride Release from Antarctic Krill(Euphausia superba)Cuticle

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Journal of Ocean University of China 2024年第3期23卷 766-774页

作者： peng Yuanhuai ji Wei ji Hongwu HAN Zhiping ZHANG Shiqi WEN Yaping College of Food Science and Engineering Lingnan Normal UniversityZhanjiang 524048China College of Biological and Food Engineering Guangdong University of EducationGuangzhou 510303China Guangdong Provincial Key Laboratory of Aquatic Products Processing and Safety Guangdong Ocean UniversityZhanjiang 524088China College of Food Science and Technology Guangdong Ocean UniversityZhanjiang 524088China College of Continuing Education Lingnan Normal UniversityZhanjiang 524048China

During postmortem storage,fluoride in Antarctic krill can be enriched in the ***,as the most important digestive enzyme in Antarctic krill with a high activity in low temperature,plays a potential role in this *** this study,endogenous trypsin was purified and its properties were *** involvement of trypsin in the generation of free fluoride from Antarctic krill cuticle was *** microstructure before and after hydrolysis was compared with scanning electron microscopy,and the ash samples of the hydrolyzed Antarctic krill cuticle were analyzed with X-ray diffraction,Fourier transform infrared spectroscopy,and electron dispersive spectroscopy,*** spectrometry analysis and inhibition tests confirmed that the purified enzyme was endogenous *** of the present study indicated that trypsin digestion caused the increases of the concentrations of both fluoride ions and free amino N simultaneously,while the protein coated on the cuticle surface was dissolved ***,no compositional change was detected in the cuticle inorganic *** findings suggest that trypsin triggered free fluoride release from Antarctic krill *** addition,the kinetics of free fluoride release could be described by the equation C_(W)=(1-0.97^(-0.006t)-0.03e^(0.0558t))×337.53+*** present study improved the understanding of the role of trypsin in free fluoride release from Antarctic krill cuticle,facilitating future studies aimed at reducing the fluoride content in krill protein during Antarctic krill processing.

关键词： Antarctic krill cuticle fluoride trypsin

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Enhanced energy storage properties and good stability of novel(1-x)Na_(0.5)Bi_(0.5)TiO_(3)-xCa(Mg_(1/3)Nb_(2/3))O_(3) relaxor ferroelectric ceramics prepared by chemical modification

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Journal of Materiomics 2024年第4期10卷 770-782页

作者： Ying Zhang Meng-Han Yan Zhi-Fei Zhang Hai-Rui Bai peng Li Wei-Fang Han ji-Gong Hao Wei Li Yu-chao Li Chun-Ming Wang peng Fu School of Materials Science and Engineering Liaocheng UniversityLiaocheng252059China Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing 300 Changjiang RoadYantai264006China School of Physics Shandong UniversityJinan250100China

The increase in energy consumption and its collateral damage on the environment has encouraged the development of environment-friendly ceramic materials with good energy storage *** this work,(1-x)Na_(0.5)Bi_(0.5)TiO_(3)-xCa(Mg_(1/3)Nb_(2/3))O_(3) ceramics were synthesized by the solid-state reaction *** 0.88Na_(0.5)Bi_(0.5)TiO_(3)-0.12Ca(Mg_(1/3)Nb_(2/3))O_(3) ceramic exhibited a high recoverable energy storage density of 8.1 J/cm3 and energy storage efficiency of 82.4% at 550 kV/*** introduction of Ca(Mg_(1/3)Nb_(2/3))O_(3) reduced the grain size and increased the band gap,thereby enhancing the breakdown field strength of the ceramic *** method also resulted in good temperature stability(20–140℃),frequency stability(1–200 Hz),and fatigue stability over 106 *** addition,an ultrahigh power density of 187 MW/cm^(3) and a fast charge-discharge rate(t0.9=57.2 ns)can be obtained *** element method analysis revealed that the decrease of grain size was beneficial to the increase of breakdown field ***,the 0.88Na_(0.5)Bi_(0.5)TiO_(3)-0.12Ca(Mg_(1/3)Nb_(2/3))O_(3) ceramics resulted in high energy storage properties with good stability and were promising environment-friendly materials for advanced pulsed power systems applications.

关键词： (1-x)Na_(0.5)Bi_(0.5)TiO_(3)-xCa(Mg_(1/3)Nb_(2/3))O_(3)ceramics Relaxor ferroelectrics Breakdown field strength Energy storage properties Stability

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Effects of cooling rate on microstructure and microhardness of directionally solidified Galvalume alloy

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China Foundry 2024年第3期21卷 213-220页

作者： ji-peng Li De-gao Qiao jian Li Xiao-yang Luo peng peng Xian-tao Yan Xu-dong Zhang Gansu jiu Steel Group Hongxing Iron and Steel Co. Ltd.Jiayuguan 735111GansuChina School of Materials and Energy Lanzhou UniversityLanzhou 730000China

The influences of cooling rate on the phase constitution,microstructural length scale,and microhardness of directionally solidified Galvalume(Zn-55Al-1.6Si)alloy were investigated by directional solidification experiments at different withdrawal speeds(5,10,20,50,100,200,and 400μm·s^(-1)).The results show that the microstructure of directionally solidified Galvalume alloys is composed of primary Al dendrites,Si-rich phase and(Zn-Al-Si)ternary eutectics at the withdrawal speed ranging from 5 to 400μm·s^(-1).As the withdrawal speed increases,the segregation of Si element intensifies,resulting in an increase in the area fraction of the Si-rich *** addition,the primary Al dendrites show significant refinement with an increase in the withdrawal *** relationship between the primary dendrite arm spacing(λ_(1))and the thermal parameters of solidification is obtained:λ_(1)=127.3V^(-0.31).Moreover,as the withdrawal speed increases from 5 to 400μm·s^(-1),the microhardness of the alloy increases from 90 HV to 151 *** is a combined effect of grain refinement and second-phase strengthening.

关键词： Galvalume alloy directional solidification microstructure length scale microhardness

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Monothetic and conductive network and mechanical stress releasing layer on micron-silicon anode enabling high-energy solid-state battery

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Rare Metals 2024年第3期43卷 1017-1029页

作者： Xiang Han Min Xu Lan-Hui Gu chao-Fei Lan Min-Feng Chen Jun-jie Lu Bi-Fu Sheng peng Wang Song-Yan Chen ji-Zhang Chen College of Materials Science and Engineering Co-Innovation Center of Efficient Processing and Utilization of Forestry ResourcesNanjing Forestry UniversityNanjing210037China Department of Physics Xiamen UniversityXiamen361005China Western Digital Corporation MilpitasCA95035USA

Silicon has ultrahigh capacity,dendrite-free alloy lithiation mechanism and low cost and has been regarded as a promising anode candidate for solid-state *** to the low infiltration of solid-state electrolyte(SSE),not the unstable solid-electrolyte interphase(SEI),but the huge stress during lithiation-and delithiation-induced particle fracture and conductivity lost tend to be the main *** this study,starting with micron-Si,a novel monothetic carbon conductive framework and a MgO coating layer are designed,which serve as electron pathway across the whole electrode and stress releasing layer,*** addition,the in situ reaction between Si and SSE helps to form a LiF-rich and mechanically stable SEI *** a result,the mechanical stability and charge transfer kinetics of the uniquely designed Si anode are significantly ***,high initial Coulombic efficiency,high capacity and durable cycling stability can be achieved by applying the Si@MgO@C anode in *** example,high specific capacity of 3224.6 mAh·g^(-1)and long cycling durability of 200 cycles are *** work provides a new concept for designing alloy-type anode that combines surface coating on particle and electrode structure design.

关键词： Lithium-ion battery(LIB) Solid-state electrolyte(SSE) Silicon anode Stress relief Coating

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Creep damage constitutive model of rock based on the mechanisms of crack-initiated damage and extended damage

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Underground Space 2024年第5期18卷 295-313页

作者： Tianbin Li chao Chen Feng peng Chunchi Ma Mou Li Yixiang Wang State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China College of Environment and Civil Engineering Chengdu University of TechnologyChengdu 610059China School of Urban Construction Chengdu PolytechnicChengdu 610218China Shudao Investment Group Co. LtdChengdu 610094China

Since the classical element model cannot describe the nonlinear characteristics of rock during the entire compressive creep process,nonlinear elements and creep damage are generally introduced in the model to resolve this ***,several previous studies have reckoned that creep damage in rock only occurs in the accelerated creep stage and is only described by the Weibull ***,the creep damage mechanism of rocks is still not clearly *** this study,a reasonable representation of the damage variables of solid materials is ***,based on the Gurson damage model,the damage state functions reflecting the constant creep stage and accelerated creep stage of rock are ***,the one-dimensional and three-dimensional creep damage constitutive equations of rock are derived by modifying the Nishihara ***,the creep-acoustic emission tests of phyllite under different confining pressures are conducted to examine the creep damage characteristics of *** the proposed constitutive model is verified by analyzing the results of creep tests performed on saturated ***,this study reveals the relationship between the creep characteristics of rocks and the corresponding damage evolution pattern,which bridges the gap between the traditional theory and the quantitative analysis of rock creep and its damage pattern.

关键词： Rock Creep damage Constitutive model Damage state function Indoor tests

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Soluble alpha-synuclein post-translational modifications:unexpected regulators of pathological alpha-synuclein amplification

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Neural Regeneration Research 2024年第5期19卷 959-960页

作者： Simran Kapila Yuhan Sun chao peng Shujing Zhang Department of Neurology David Geffen School of MedicineUniversity of CaliforniaLos AngelesCAUSA Molecular Biology Institute Brain Research InstituteMary S.Easton Center for Alzheimer’s ResearchUniversity of CaliforniaLos AngelesCAUSA

The build-up of misfoldedα-synuclein(α-syn)in the central nervous system is the pathological hallmark of a number of neurodegenerative diseases that are known asα-*** include Parkinson’s disease(PD),Parkinson’s disease with dementia(PDD),dementia with Lewy body(LB),multiple system atrophy(MSA),and a subset of Alzheimer’s *** evidence underscores that the intercellular transmission and amplification of pathologicalα-syn are critical processes underlying the progression ofα-synucleinopathies(peng et al.,2020),and as such,the study of these processes could lead to the identification of promising therapeutics to mitigate disease *** previous studies have focused solely on pathological seeds in relation to disease progression.

关键词： pathological diseases

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Gbps key rate passive-state-preparation continuous-variable quantum key distribution within an access-network area

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Photonics Research 2024年第7期12卷 1485-1493页

作者： FEIYU ji peng HUANG TAO WANG XUEQIN jiANG GUIHUA ZENG State Key Laboratory of Advanced Optical Communication Systems and Networks Center for Quantum Sensing and Information ProcessingSchool of Electronic Information and Electrical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Shanghai Research Center for Quantum Sciences Shanghai 201315China Hefei National Laboratory Hefei 230088China College of Information Science and Technology Donghua UniversityShanghai 201620China

The conventional Gaussian-modulated coherent-state quantum key distribution(QKD) protocol requires the sender to perform active modulations based on a true random number generator. Compared with it, the passive-state-preparation(PSP) continuous-variable quantum key distribution(CVQKD) equivalently performs modulations passively by exploring the intrinsic field fluctuations of a thermal source, which offers the prospect of chip integration QKD with low cost. In this paper, we propose and experimentally demonstrate a high-rate PSP-CVQKD scheme within an access-network area using high-bandwidth detectors in a continuous wave encoding and decoding way. By proposing effective methods for suppressing the noises during the PSP process and polarization multiplexing to decrease the photon leakage noises, we realize the high-intensity local oscillator transmission, thereby achieving coherent detection with high efficiency, low noise, and high bandwidth. The secure key rates over transmission distance of 5.005 km with and without consideration of the finite-size effect are 273.25 Mbps and 1.09 Gbps. The use of the PSP method boosts the asymptotic secret key rate of CVQKD to Gbps level for the first time, to our knowledge, within the range of the access network, which provides an effective and secure key distribution strategy for high-speed quantum cryptography access communication.

关键词： passive network distribution

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Supermassive black holes triggered by QCD axion bubbles

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Communications in Theoretical Physics 2024年第5期76卷 134-139页

作者： Hai-Jun Li Ying-Quan peng Wei chao Yu-Feng Zhou Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China Center for Advanced Quantum Studies Department of PhysicsBeijing Normal UniversityBeijing 100875China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China International Centre for Theoretical Physics Asia-Pacific Beijing/HangzhouChina

Supermassive black holes(SMBHs)are ubiquitous in the center of galaxies,although the origin of their massive seeds is still *** this paper,we investigate the formation of SMBHs from the quantum chromodynamics(QCD)axion *** this case,primordial black holes(PBHs)are considered as the seeds of SMBHs,which are generated from the QCD axion bubbles due to an explicit Peccei–Quinn(PQ)symmetry breaking after *** QCD axion bubbles are formed when the QCD axion starts to oscillate during the QCD phase *** consider a general case in which the axion bubbles are formed with the bubble effective angle θ_(eff)∈(0,π],leading to the minimum PBH mass∼■(10^(4)−10^(7))M⊙for the axion decay constant f_(a)∼■(10^(16))*** PBHs at this mass region may account for the seeds of SMBHs.

关键词： supermassive black holes primordial black holes quantum chromodynamics axion

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Clinical practice guideline for acupuncture and moxibustion: Female urinary incontinence

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Journal of Integrative Medicine 2024年第3期22卷 258-269页

作者： chao Yang Shan-ze Wang Sheng Chen Shuo Du Guan-qun Wang Wei Guo Xiao-long Xie Bi-hui peng Shi-hao Du ji-ping Zhao Department of Acupuncture and Moxibustion Dongzhimen HospitalBeijing University of Chinese MedicineBeijing 100700China Department of Acupuncture and Moxibustion Guangdong provincial hospital of Chinese MedicineGuangzhou 510120Guangdong ProvinceChina Shanghai Ninth People’s Hospital Shanghai Jiao Tong University School of MedicineShanghai 200011China Institute of Acupuncture and Moxibustion China Academy of Chinese Medical SciencesBeijing 100700China

Urinary incontinence (UI) is a common problem *** has a major impact on physical and social activities and interpersonal *** is common in women,but is under-reported and *** affects the quality of life of female patients *** and moxibustion have been proposed as potentially effective interventions for female ***,for the benefit of acupuncture practitioners around the world,the World Federation of Acupuncture-moxibustion Societies initiated a project to develop a clinical practice guideline (CPG) for the use of acupuncture and moxibustion to treat female *** CPG was developed according to the Grading of Recommendations Assessment,Development,and Evaluation (GRADE) methodology,referring to the principles of the World Health Organization Handbook for Guideline *** the development of the CPG,the guideline development group (GDG) played an important *** clinical questions,recommendations and therapeutic protocols were all formulated by GDG using the modified Delphi *** CPG contains ten recommendations about the use of acupuncture and moxibustion interventions for ten clinical questions,which include nine conditional recommendations for the intervention and one conditional recommendation for either the intervention or the *** CPG also provides one protocol for conventional filiform needle therapy,two therapy protocols for deep needling stimulation on lumbosacral acupoints,and four moxibustion therapy protocols,based on the protocols presented in randomized controlled trials reviewed by the GDG.

关键词： Acupuncture Clinical practice guideline Female urinary incontinence Moxibustion GRADE

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