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Synthesis of Piperazic Acid-Containing Cyclodepsipeptide Core of Verucopeptin

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Chinese Journal of Chemistry 2023年第17期41卷 2077-2081页

作者： Yuanjun Sun Wenhao Tang Mei Wang Huxin Ni ya-qiu long Laboratory of Medicinal Chemical Biology College of Pharmaceutical SciencesJiangsu Province Engineering Research Centerof Precision Diagnostics and Therapeutics DevelopmentSoochow UniversitySuzhouJiangsu 215123China

Comprehensive SummaryChemically,N1 nitrogen of piperazic acid is more nucleophilic than N2 nitrogen,but amide bonds predominantly formed at N2 nitrogen are prevalent in piperazic acid-containing natural products,with only one exception of *** two orthogonal protecting groups of nitrogen are often employed to realize selective coupling of N2 nitrogen,resulting in increased synthetic steps and low synthetic ***,we develop selective deprotection of N2-Cbz from the N1,N2-diCbz-piperazic acid-containing peptide to form the N2 amide exclusively,avoiding the tedious orthogonal protection strategy which is commonly applied when the easily-accessible N1,N2-diCbz-piperazic acid is used as the synthetic *** employ this selective-deprotection strategy to achieve an efficient synthesis of piperazic acid-containing cyclodepsipeptide core of verucopeptin with an overall yield of 21%from commercially/readily available building blocks.

关键词： Natural products Piperazic acid Verucopeptin Total synthesis Regioselectivity

A highly selective electrochemical impedimetric sensor for imidacloprid determination based on WO_(3)/MoS_(2)nanosheets/molecularly imprinted polymer composite

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Rare Metals 2024年第3期43卷 1309-1315页

作者： long-Hua Ding ya-Wen Wang qiu-Wen Li Li-Li Zhang Ai-Zhu Wang Institute for Advanced Interdisciplinary Research School of Chemistry and Chemical EngineeringUniversity of JinanJinan250022China HCA Florida Healthcare Westside/Northwest Hospital Internal Medicine PlantationFL33324USA

In this study,an electrochemical impedimetric sensor was established for imidacloprid(IMI)detection based on WO_(3)/MoS_(2)and molecular imprinted polymer(MIP)*** layer was prepared on electrode surface by electropolymerization of o-phenylenediamine(o-PD)in the presence of IMI template,which ensured the specific rec-ognization toward IMI.

关键词： electrochemical polymer polymerization

Essential oils improve nursery pigs'performance and appetite via modulation of intestinal health and microbiota

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Animal Nutrition 2024年第1期16卷 174-188页

作者： Bi-Chen Zhao Tian-Hao Wang Jian Chen Bai-Hao qiu ya-Ru Xu Jin-long Li College of Veterinary Medicine Northeast Agricultural UniversityHarbin150030China Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine Northeast Agricultural UniversityHarbin150030China Key Laboratory of the Provincial Education Department of Heilongjiang for Common Animal Disease Prevention and Treatment Northeast Agricultural UniversityHarbin150030China

Optimal intestinal health and functionality are essential for animal health and performance,and simultaneously intestinal nutrient transporters and intestinal peptides are also involved in appetite and feed intake control *** the potential of essential oil(EO)in improving animal performance and improving feed palatability,we hypothesized that dietary supplementation of cinnamaldehyde and carvacrol could improve performance and appetite of nursery pigs by modulating intestinal health and ***(100 mg/kg),carvacrol(100 mg/kg),and their mixtures(including 50 mg/kg cinnamaldehyde and 50 mg/kg carvacrol)were supplemented into the diets of 240 nursery pigs for 42 d,and data related to performance were ***,the influence of EO on intestinal health,appetite and gut microbiota and their correlations were *** supplementation increased(P<0.05)the body weight,average daily gain(ADG)and average daily feed intake(ADFI)of piglets,and reduced(P<0.05)diarrhea rates in nursery ***,EO increased(P<0.05)the intestinal absorption area and the abundance of tight junction proteins,and decreased(P<0.05)intestinal permeability and local *** terms of intestinal development and the mucus barrier,EO promoted intestinal development and increased(P<0.05)the number of goblet ***,we found that piglets in the EO-supplemented group had upregulated(P<0.05)levels of transporters and digestive enzymes in the intestine,which were significantly associated with daily gain and feed *** addition,EO supplementation somewhat improved appetite in nursery pigs,increased the diversity of the gut microbiome and the abundance of beneficial bacteria,and there was a correlation between altered bacterial structure and appetite-related *** findings indicate that EO is effective in promoting growth performance and nutrient absorption as well as in regulating appetite by improving intestinal health and ba

关键词： Nursery pig Essential oil Intestinal health Appetite Microbiota

Colorimetric Detection of Acid Phosphatase and Malathion Using NiCo_(2)O_(4)Nanosheets as Peroxidase-Mimicking Activity

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Journal of Analysis and Testing 2024年第2期8卷 170-179页

作者： Jia Chen Zerong long yan Li Hongdeng qiu Xinjiang Uygur Autonomous Product Quality Supervision and Inspection Institute Urumqi830000China CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou730000China

The establishment of a low-cost and facile approach for the assay of acid phosphatase(ACP)and its inhibitor is a research *** this paper,we successfully synthesized NiCo_(2)O_(4)nanosheets with peroxidase-mimicking activity in alkaline deep eutectic solvents(DESs)composed of NaOH and PEG-200,which can catalyze 3,3',5,5'-tetramethylbenzidine(TMB)to the oxidation state TMB(ox-TMB)in the presence of *** to L-ascorbic acid-2-phosphate can be hydrolyzed into ascorbic acid by ACP,the peroxidase-like activity of NiCo_(2)O_(4)nanosheets is ***,the addition of malathion,an inhibitor of ACP,can inhibit the activity of ACP and thus limit the production of ascorbic acid(AA).Therefore,a colorimetric approach can be established for highly sensitive and selective detection of ACP and malathion with detection limits of 0.032 U/L and 0.65 nmol/L,*** importantly,this method can be successfully applied to malathion detection in environmental samples tap water and food cucumber juice,indicating that it has potential application prospects in environmental and agricultural fields.

关键词： NiCo_(2)O_(4)nanosheets Acid phosphatase Malathion Peroxidase-mimicking activity Colorimetric

The Emergence of Functional Ultrasound for Noninvasive Brain-Computer Interface

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Research 2024年第2期6卷 301-317页

作者： Hairong Zheng Lili Niu Weibao qiu Dong Liang Xiaojing long Guanglin Li Zhiyuan Liu long Meng Institute of Biomedical and Health Engineering Shenzhen Institutes of Advanced TechnologyChinese Academy of SciencesShenzhen518055China Shenzhen Institute of Advanced Integration Technology Chinese Academy of Sciences and The Chinese University of Hong KongShenzhen518055China

A noninvasive brain-computer interface is a central task in the comprehensive analysis and understanding of the brain and is an important challenge in international brain-science *** implanted brain-computer interfaces are cranial and invasive,which considerably limits their *** development of new noninvasive reading and writing technologies will advance substantial innovations and breakthroughs in the field of brain-computer ***,we review the theory and development of the ultrasound brain functional imaging and its ***,we introduce latest advancements in ultrasound brain modulation and its applications in rodents,primates,and human;its mechanism and closed-loop ultrasound neuromodulation based on electroencephalograph are also ***,high-frequency acoustic noninvasive brain-computer interface is prospected based on ultrasound super-resolution imaging and acoustic tweezers.

关键词： breakthrough computer Computer

Algorithms and statistical analysis for linear structured weighted total least squares problem

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Geodesy and Geodynamics 2024年第2期15卷 177-188页

作者： Jian Xie Tianwei qiu Cui Zhou Dongfang Lin Sichun long School of Earth Science and Spatial Information Engineering Hunan University of Science and TechnologyXiangtan 411201China College of Science Central South University of Forestry and TechnologyChangsha 410018China National-Local Joint Engineering Laboratory of Geo-spatial Information Technology Hunan University of Science and TechnologyXiangtan 411201China

Weighted total least squares(WTLS)have been regarded as the standard tool for the errors-in-variables(EIV)model in which all the elements in the observation vector and the coefficient matrix are contaminated with random ***,in many geodetic applications,some elements are error-free and some random observations appear repeatedly in different positions in the augmented coefficient *** is called the linear structured EIV(LSEIV)*** kinds of methods are proposed for the LSEIV model from functional and stochastic *** the one hand,the functional part of the LSEIV model is modified into the errors-in-observations(EIO)*** the other hand,the stochastic model is modified by applying the Moore-Penrose inverse of the cofactor *** algorithms are derived through the Lagrange multipliers method and linear *** estimation principles and iterative formula of the parameters are proven to be *** first-order approximate variance-covariance matrix(VCM)of the parameters is also derived.A numerical example is given to compare the performances of our proposed three algorithms with the STLS ***,the least squares(LS),total least squares(TLS)and linear structured weighted total least squares(LSWTLS)solutions are compared and the accuracy evaluation formula is proven to be feasible and ***,the LSWTLS is applied to the field of deformation analysis,which yields a better result than the traditional LS and TLS estimations.

关键词： Linear structured weighted total least squares Errors-in-variables Errors-in-observations Functional modelmodification Stochastic model modification Accuracyevaluation

Absorbed Bioactive Compounds Replicate GuanxinⅡ-Induced Endothelium-Associated in/ex vivo Vasodilation

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Chinese Journal of Integrative Medicine 2024年第5期30卷 387-397页

作者： XU Min LIU Hao SU Meng-qing LI Lan YU Ai-ling CHEN Ken HUANG Yun-ke ZHAO qiu-long HUANG Wen-ya HUANG Xi Institute of Traditional Chinese Medicine Related Comorbid Depression Nanjing University of Chinese MedicineNanjing 210029China Department of Gynecology Women's HospitalZhejiang University School of MedicineHangzhou 310053China

Objective:To develop an interference-free and rapid method to elucidate GuanxinⅡ(GXⅡ)'s representative vasodilator absorbed bioactive compounds(ABCs)among enormous ***:The contents of ferulic acid,tanshinol,and hydroxysafflor yellow A(FTA)in GXⅡ/rat serum after the oral administration of GXⅡ(30 g/kg)were detected using ultra-performance liquid chromatography-mass *** 18 rats were randomly assigned to the control group(0.9%normal saline),GXⅡ(30 g/kg)and FTA(5,28 and 77 mg/kg)by random number table *** coronary flow velocity-time integral(VTI),i.e.,coronary flow or coronary flow-mediated dilation(CFMD),and endothelium-intact vascular tension of isolated aortic rings were *** 12 h of exposure to blank medium or 0.5 mmol/L H_(2)O_(2),endothelial cells(ECs)were treated with post-dose GXⅡof supernatant from deproteinized serum(PGSDS,300μL PGSDS per 1 m L of culture medium)or FTA(237,1539,and 1510 mg/m L)for 10 min as control,H_(2)O_(2),PGSDS and FTA *** oxide(NO),vascular endothelial growth factor(VEGF),endothelin-1(ET-1),superoxide dismutase(SOD),malondialdehyde(MDA)and phosphorylated phosphoinositide 3 kinase(p-PI3K),phosphorylated protein kinase B(p-AKT),phosphorylated endothelial nitric oxide synthase(p-e NOS)were *** was developed as a GXⅡproxy of ex vivo herbal crude ***:PGSDS effectively eliminates false responses caused by crude GXⅡ*** doses equaled the contents in GXⅡ/its post-dose serum,FTA accounted for 98.17%of GXⅡ-added CFMD and 92.99%of PGSDS-reduced vascular *** ECs,FTA/PGSDS was found to have significant antioxidant(lower MDA and higher SOD,P<0.01)and endothelial function-protective(lower VEGF,ET-1,P<0.01)*** increases in aortic relaxation,endothelial NO levels and phosphorylated PI3K/Akt/e NOS protein induced by FTA/PGSDS were markedly abolished by NG-nitro-L-arginine methyl ester(L-NA,e NOS inhibitor)and wortmannin(PI3K/AKT inhibitor

关键词： ultra-performance liquid chromatography-mass spectrometry endothelium-dependent vasodilation herbal extract GuanxinⅡ absorbed bioactive compound

Highly Improved Creep Resistance in Polypropylene Through Thermally Reduced Graphene Oxide and Its Creep Lifetime Prediction

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Chinese Journal of Polymer Science 2024年第2期42卷 256-266,I0010页

作者： Can-Can Zhang Jun-long yang ya-Jiang Huang Guang-Xian Li College of Polymer Science and Engineering State Key Laboratory of Polymer Materials Engineering of ChinaSichuan UniversityChengdu610065China

Polypropylene(PP) exhibits suboptimal creep resistance due to the presence of methyl groups on its main chain, leading to irregular chain segment distribution, diminished inter-chain interaction, and crystallinity. This structural feature causes chain slippage in PP under stress,significantly constraining its service lifetime. In this study, thermally reduced graphene oxide(TrGO) nanosheets were incorporated into the PP matrix, yielding a nanocomposite with exceptional creep resistance performance. Results demonstrated that at a stress of 25 MPa, a 2.0 wt% TrGO content could enhance the creep failure lifetime of PP by 21.5 times compared to neat PP. Rheology, transmission electron microscopy(TEM),and scanning electron microscopy(SEM) characterization techniques were employed to analyze the mechanism of TrGO's influence on PP's creep behavior. It was observed that when TrGO content exceeded 1.0 wt%, an effective particle network structure formed within the PP matrix. This homogeneously dispersed TrGO-formed particle network structure restricted the migration and rearrangement of PP molecular chains, enabling prolonged stress resistance without structural failure. By combining the time-strain superposition method with the critical failure strain as a criterion, generalized creep compliance curves for PP and its composites were established, facilitating the prediction of material creep failure lifetimes, with a strong agreement between experimental and predicted lifetime values. This research proposes a novel strategy aimed at developing polypropylene materials and products with enhanced long-term stability and durability, thus extending service life, reducing failure risk, and broadening their potential across various application domains.

关键词： Thermally reduced graphene oxide Polypropylene Creep failure and lifetime prediction

pH Induced Self-assembly of AIE Fluorescent Probe for Tumor Imaging

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Chinese Journal of Polymer Science 2024年第1期42卷 7-13,I0005页

作者： Jing-Yuan Xiang Wen-long Zhang He-Ting Li ya-Ning He Department of Chemical Engineering Key Laboratory of Advanced Materials(MOE)Tsinghua UniversityBejing 100084China

This work reported an AIE fluorescent probe for tumor imaging based on the p H induced self-assembly strategy. The fluorescent probe was composed of an acid-responsive soluble copolymer PEG-b-PAMA-DMMA with a maleic acid amide group and an anionic soluble aggregation-induced emission fluorogen(AIEgen) TPE-2SO_(3)^(-). The polymer could be transformed into a protonated amine-containing polymer after the hydrolysis of maleic acid amide in acidic tumor microenvironment, which would be further self-assembled with TPE-2SO_(3)^(-)to form aggregated nanoparticles. The transition of TPE-2SO_(3)^(-)from dispersed state to aggregated state led to an obvious increase in fluorescence intensity due to its AIE characteristics.

关键词： p H-responsive Self-assembly Fluorescent probe AIE Tumor imaging