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A Novel Angiotensin I Converting Enzyme Inhibitory Peptide from the Milk Casein:Virtual Screening and Docking Studies

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Agricultural Sciences in China 2011年第3期10卷 463-467页

作者： WANG Zhan-li ZHANG sai-sai WANG Wei FENG Feng-qin SHAN Wei-guang Department of Food Science and Nutrition Zhejiang University Hangzhou 310029 P.R.China College of Pharmaceutical Science Zhejiang University of Technology Hangzhou 310014 P..R. China Institute of Quality and Standard for Agriculture Products Zhejiang Academy of Agriculture Sciences Hangzhou 310021 P.R.China

Angiotensin I converting enzyme （ACE） plays an important physiological role in the regulation of hypertension. In this study, we applied virtual screening to discover a novel angiotensin I converting enzyme inhibitory peptides from milk casein. One potential hit was identified based on docking scores, subsequently confirmed by activity studies in vitro （IC50=20.85 μmol L-1）. The proposed peptide in this study contains a unique sequence, Lys-Val-Leu-Ile-Leu-Ala. Moreover, we performed the docking studies to understand the binding mode between the enzyme and peptide hit.

关键词： novel angiotensin I converting enzyme inhibitory peptide virtual screening docking

Pioneering observation of atmospheric volatile organic compounds in Hangzhou in eastern China and implications for upcoming 2022 Asian Games

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Journal of Environmental Sciences 2023年第2期124卷 723-734页

作者： Bowei li Steven sai Hang Ho Xinhe li liya Guo Rui Feng Xuekun Fang College of Environmental&Resource Sciences Zhejiang UniversityHangzhou 310058China Division of Atmospheric Sciences Desert Research InstituteRenoNevada89512USA Center for Global Change Science Massachusetts Institute of TechnologyCambridgeMassachusetts 02139USA

Understanding the emission sources of volatile organic compounds(VOCs)is critical for air pollution *** measurements of atmospheric VOCs were conducted from January to February in Hangzhou in *** average measured concentration of total VOCs(TVOCs)was 38.2±20.9 ppb,>42% lower than that reported by previous studies at the urban center in *** VOC concentrations and proportions were similar between weekdays and *** the long holidays of the Spring Festival in China,the concentrations of TVOCs were∼50% lower than those during the regular days,but their profiles showed no significant difference(p>0.05).Further,we deduced that aromatics and alkenes were the most crucial chemicals promoting the formation of O3 and secondary organic aerosol(SOA)in *** to interspecies correlations,combustion processes and solvent use were inferred as major VOC emission *** study provides implications for air quality improvements before and during the upcoming Asian Games that will be hosted in Hangzhou in 2022.

关键词： VOCs Atmospheric observation Eastern China 2022 Asian game Air quality improvements

Development and analysis of a novel AF11-2 aptamer capable of enhancing the fluorescence of aflatoxin B1

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Chinese Chemical Letters 2022年第8期33卷 4096-4100页

作者： Wenjing li Yian pei Jine Wang School of Nano-Tech and Nano-Bionics University of Science and Technology of ChinaHefei 230026China CAS Key Laboratory of Nano-Bio Interface Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123China

Aflatoxin B1(AFB1)is one of the most common mycotoxins that threatens human *** singlestranded oligonucleotides with high affinity and specificity,aptamers have incomparable effect on the targeted detection of ***,after 11 rounds of selection and analysis using a modified affinity chromatography-based SELEX strategy,the truncated 37 nt aptamer AF11-2 was successfully *** aptamer shows good detection performance for AFB1,and can sensitively detect AFB1 in the range of 100-1000 nmol/L,with a detection limit of 42 nmol/*** the detection of pretreated edible peanut oil samples,AF11-2 aptamer also showed a high recovery rate and good stability for AFB1,and achieved satisfactory *** addition,AF11-2 aptamer can significantly enhance the fluorescence ability of AFB1,which is not available in traditional Afla17-2-3 *** molecular docking analysis,it was found that AF11-2 and Afla17-2-3 had different nucleotide binding sites for ***17-2-3 binds to the carbonyl O of AFB1,while AF11-2 binds to the pyrrolic O of AFB1,which may be the main reason that AF11-2 can enhance the fluorescence of AFB1.

关键词： Aptamer AF11-2 Targeted detection Aflatoxin B1 Enhanced fluorescence Docking analysis

Microstructure evolution of eutectic Nb–24Ti–15Si–4Cr–2Al–2Hf alloy processed by directional solidification

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Rare Metals 2017年第6期36卷 472-477页

作者： Zhen li sai-Nan Yuan li-Na Jia Bin Kong Zhen Hong Hu Zhang School of Materials Science and Engineering Beihang Universtity Beijing 100191 China

In this work, the near-eutectic Nb-24Ti-15Si-4Cr-2Al-2Hf（at%） alloy was directionally solidified at 1900 ℃ with withdrawal rates of 6, 18, 36, 50 mm·min^-1 and then heat-treated at 1450 ℃ for 12 h. The microstructure evolution was investigated. The results show that the microstructure of the directionally solidified（DS） alloy is composed of Nbss＋Nb5Si3 eutectics within the whole withdrawal rate range, while the variation of rates makes a great difference on the solidification routes,the morphology and size of Nb_（ss）＋Nb_5Si_3 eutectic *** the increase in withdrawal rates, the petaloid Nbss＋Nb5Si3 eutectic cells transform into granular morphology. After the heat treatment, a mesh structure Nbssis formed gradually which isolates the Nb5Si3, and the phase boundaries become smoother in order to reduce the interfacial energy. Moreover, two kinds of Nb5Si3 exist in the heat-treated（HT） samples identified by crystal form and element composition, which are supposed as α-Nb5Si3 and γ-Nb5Si3, respectively. This study exhibits significant merits in guiding the optimization of Nb-Si-based alloys＇ mechanical properties.

关键词： Nb-Si-based alloy Directional solidification Heat treatment Microstructure evolution Intermetallic

Quinine-derived thiourea promoted enantioselective Michael addition reactions of 3-substituted phthalides to maleimides

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Science China Chemistry 2019年第5期62卷 649-652页

作者： Jie Wang Xin li Jin-pei Cheng State Key Laboratory of Elemento-Organic Chemistry Collaborative Innovation Center of Chemical Science and EngineeringCollege of ChemistryNankai University

A highly diastereoselective and enantioselective Michael addition/desymmetrization reaction of maleimides with prochiral 3-substituted phthalides catalyzed by quinine-derived bifunctional thiourea was realized. A broad range of the 3,3′-disubstituted phthalides bearing vicinal quaternary-tertiary stereogenic centers were synthesized in moderate to good yields(up to 96%) with high diastereoselectivities(up to >19:1 dr) and enantioselectivities(up to 96:4 er).

关键词： michael addition 3,3′-disubstituted phthalides vicinal quaternary-tertiary stereogenic centers

Effects of surfactants on the combined toxicity of TiO_2 nanoparticles and cadmium to Escherichia coli

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Journal of Environmental Sciences 2018年第12期30卷 126-133页

作者： Mei li Jianchuan pei Xiaomeng Tang Xiaoli Guo School of Environmental and Resource Sciences Zhejiang A & F University

The combined ecological toxicity of TiO2 nanoparticles（nano-TiO2） and heavy metals has been paid more attention. As the common pollutants in water environment, surfactants could affect the properties of nanoparticles and heavy metals, and thus further influence the combined toxicity of nano-TiO2 and heavy metals. In this study, the effects of sodium dodecyl benzene sulfonate（SDBS） and Tween 80 on the single and combined toxicities of Cd2＋ and nano-TiO2 to Escherichia coli（E. coli） were examined, and the underlying influence mechanism was further discussed. The results showed both SDBS and Tween 80 enhanced the toxicity of Cd2＋ to E. coli in varying degrees. The reaction of SDBS and Cd2＋ could increase the outer membrane permeability and the bioavailability of Cd, while Tween 80 itself could enhance the outer membrane permeability. The combined toxicity of nano-TiO2 and Cd2＋ to E. coli in absence of surfactant was antagonistic because of the adsorption of Cd2＋ to nanoTiO2 particles. However, in the presence of SDBS, both SDBS and nano-TiO2 influenced the toxicity of Cd2＋ , and also SDBS could adsorb to nano-TiO2 by binding to Cd2＋ . The combined toxicity was reduced at Cd2＋ lower than 4 mg/L and enhanced at Cd2＋ higher than 4 mg/L under multiple interactions. Tween 80 enhanced the combined toxicity of nano-TiO2 and Cd2＋ by increasing the outer membrane permeability. Our study firstly elucidated the effects of surfactants on the combined toxicity of nano-TiO2 and Cd2＋ to bacteria, and the underlying influencing mechanism was proposed.

关键词： Nano-TiO2 Heavy metal Surfactant Combined toxicity Bacteria

Hydrogen Storage Alloy and Carbon Nanotubes Mixed Catalyst in a Direct Borohydride Fuel Cell

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Journal of Materials Science & Technology 2011年第12期27卷 1089-1093页

作者： sai li Xiaodong Yang Haiyan Zhu Yan liu Yongning liu State Key Laboratory for-Mechanical Behavior of Materials School of Materials Science and Engineering Xi＇an Jiaotong University Xi＇an 710049 China Department of chemistry and chemical Engineering Weinan Normal University Weinan 714000 China

In this study, carbon nanotubes （CNTs） were mixed with ABs-type hydrogen storage alloy （HSA）, as catalyst for an anode in a direct borohydride fuel cell （DBFC）. As comparision, a series of traditional carbon materials, such as acetylene black, Vulcan XC-72R, and super activated carbon （SAC） were also employed. Electrochemical measurements showed that the electrocatalytic activity of HSA was improved greatly by CNTs. The current density of the DI3FC employing the HSA/CNTs catalytic anode could reach 1550 ***-2 （at -0.6 V vs the EIg/HgO electrode） and the maximum power density of 65 ***-2 for this cell could be achieved at room temperature. Furthermore, the life time test lasting for 60 h showed that the cell displayed a good stability.

关键词： Direct borohydride fuel cell Carbon nanotubes Hydrogen storage alloy Electrocatalytic activity

Machining Error Control by Integrating Multivariate Statistical Process Control and Stream of Variations Methodology

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Chinese Journal of Aeronautics 2012年第6期25卷 937-947页

作者： WANG pei ZHANG Dinghua li Shan CHEN Bing Key Laboratory of Contemporary Design and Integrated Manufacturing Technology Ministry of Education Northwestern Polyteehnical University Xi'an 710072 China

For aircraft manufacturing industries, the analyses and prediction of part machining error during machining process are very important to control and improve part machining quality. In order to effectively control machining error, the method of integrating multivariate statistical process control （MSPC） and stream of variations （SoV） is proposed. Firstly, machining error is modeled by multi-operation approaches for part machining process. SoV is adopted to establish the mathematic model of the relationship between the error of upstream operations and the error of downstream operations. Here error sources not only include the influence of upstream operations but also include many of other error sources. The standard model and the predicted model about SoV are built respectively by whether the operation is done or not to satisfy different requests during part machining process. Secondly, the method of one-step ahead forecast error （OSFE） is used to eliminate autocorrelativity of the sample data from the SoV model, and the T2 control chart in MSPC is built to realize machining error detection according to the data characteristics of the above error model, which can judge whether the operation is out of control or not. If it is, then feedback is sent to the operations. The error model is modified by adjusting the operation out of control, and continually it is used to monitor operations. Finally, a machining instance containing two operations demonstrates the effectiveness of the machining error control method presented in this paper.

关键词： machining error multivariate statistical process control stream of variations error modeling one-step ahead forecast error error detection

A nonlinear equivalent circuit method for analysis of passive intermodulation of mesh reflectors

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Chinese Journal of Aeronautics 2014年第4期27卷 924-929页

作者： Jiang Jie li Tuanjie Ma Xiaofei Wang pei School of Electromechanical Engineering Xidian University Xi’an Institute of Space Radio Technology

Passive intermodulation（PIM） has gradually become a serious electromagnetic interference due to the development of high-power and high-sensitivity RF/microwave communication systems, especially large deployable mesh reflector antennas. This paper proposes a field-circuit coupling method to analyze the PIM level of mesh reflectors. With the existence of many metal–metal（MM） contacts in mesh reflectors, the contact nonlinearity becomes the main reason for PIM generation. To analyze these potential PIM sources, an equivalent circuit model including nonlinear components is constructed to model a single MM contact so that the transient current through the MM contact point induced by incident electromagnetic waves can be calculated. Taking the electric current as a new electromagnetic wave source, the far-field scattering can be obtained by the use of electromagnetic numerical methods or the communication link method. Finally, a comparison between simulation and experimental results is illustrated to verify the validity of the proposed method.

关键词： Contact nonlinearity Equivalent circuit Mesh reflector Metal-metal contact Nonlinear distortion Passive intermodulation Scattering