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NPid: an automatic approach torapid identification of known natural products in the crude extract of crabapplebased on 2D ~1H-13C heteronuclear correlation spectra of the extract mixture

NPid: an automatic approach torapid identification of known ...

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中国化学会第二十届全国有机分析及生物分析学术研讨会

作者： Tao huang kaifeng hu State Key Laboratory of Phytochemistry and Plant Resources in West China Kunming Institute of BotanyChinese Academy of Sciences University of Chinese Academy of Sciences Innovative Institute of Chinese Medicine and Pharmacy Chengdu University of Traditional Chinese Medicine

An automatic approach to identification of natural products in complex extracts, termed NPid, is introduced, which integrated information of chemical shifts, adjacent relationships and peak intensities of 1 H-13 C groups to identify natural products in complex *** the crude extract of crabapple（Malusfusca）, as an example, we looked up the spectral data of natural products isolated from plants of the genus Malus reported in the literature and constructed a customized NMR database. Based on the customized NMR database, we developed a novel algorithm for automatic identification of natural products in crude extracts by exploring pure shift HSQC（psHSQC） and H2 BC spectra of the ***, standards in the customized database are recognized as candidates if the chemical shifts of their multiple 1 H-13 C groups simultaneously match the signals inpsHSQC spectrum of the complex mixture and a score of chemical shift matching（CS） is given. Next, the identities of the candidates are further checked by the adjacent relationships among their 1 H-13 C groups. For candidates with 1 H-13 C groups in adjacency, crosspeaks between the adjacent 1 H-13 C groups are expected to be observed in H2 BC spectrum and a score of adjacent relationship matching（AR） is given. Then, peak intensities of signals derived from the same candidate in the high-resolution psHSQC spectrum should be consistent with each other. The identities of the candidates can thus be further evaluated by the consistency of peak intensities of the candidate peaks and a score of consistency of peak intensities（PI） is given. Lastly, a weighted comprehensive scoreis calculated for each candidate from the values of CS, AR and PI. Proof of concept of the proposed method was first elucidated on a model mixture consisting of 10 known natural products. Application of this method was then demonstrated on an authentic sample of crude extract of crabapple and 21 known natural products were successfully identified and

关键词： NMR Automatic Identification Natural Products Complex Extract

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Quick Compound Screening based on MS-molecular-network for targeted isolation and efficient discovery of new natural products from the crude extracts of crabapples using UPLC-DAD-MS-SPE/NMR

Quick Compound Screening based on MS-molecular-network for t...

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中国化学会第二十届全国有机分析及生物分析学术研讨会

作者： Chen pengyu kaifeng hu State Key Laboratory of Phytochemistry and Plant Resources in West China Kunming Institute of Botany Chinese Academy of Sciences University of Chinese Academy of Sciences Innovative Institute of Chinese Medicine and Pharmacy Chengdu University of Traditional Chinese Medicine

MS/MS molecular networking developed in recent years is a powerful technique for dereplication of natural products, which can combine with other dereplication tools, such as MS/MS spectral libraries, and UPLC-DAD-MS-SPE to rapidly identify known compounds and targetedly isolate unknown compounds. Following Global Natural Products Social Molecular Networking（GNPS） workflow, compounds with similar MS/MS spectrum pattern cluster together in the molecular network and multiple types of natural product clusters show up in the molecular network, which can be visualized by Cytoscape. Screening the precursor ions in the clusters, some compounds can be directly identified by referencing their MS/MS fragment ions to spectral libraries, including the GNPS inherent spectral libraries, customized MS/MS spectral libraries of natural products from crabapples and third-party MS/MS spectral libraries, such as HMDB. With those identified compounds serving as seeds, the identities of large part of other precursor ions in the clusters can be quickly deduced based on the similarity of the MS/MS spectrum pattern. The remaining unidentified precursor ions in the clusters or isolated ions, that is, the dereplicated ions most likely correspond to new natural products. These ions are then sorted by the intensity, and sequentially, targetedly isolated and enriched from the crude extracts of crabapples（Malus robusta Rehd） according to their mass and retention times using UPLC-DAD-MS-SPE for efficient discovery of new natural products. A new tartaric acid derivative and a new phenolic acid were discovered and isolated from the crude extract of crabapple, meanwhile, multiple compounds, though with known structures, were isolated from crabapple for the first time. Finally, the structures of the new and known compounds were elucidated or verified by 1 D and 2 D NMR spectra. In conclusion, the proposed strategy can facilitate the discovery of new natural products by dereplication of known compounds

关键词： molecular networking UPLC-DAD-MS-SPE dereplication targeted isolation crabapples

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Accurate quantification of exo-and endogenous blood glucose by isotope dilution LC-MS/MS with indirect MRM of the derivative tag

Accurate quantification of exo-and endogenous blood glucose ...

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中国化学会第十九届全国有机分析及生物分析学术研讨会

作者： Lingling Yu Chao Wen Xing Li Shiqi Fang kaifeng hu State Key Laboratory of Phytochemistry and Plant Resources in West China Kunming Institute of BotanyChinese Academy of Sciences School of Chemical Science and Technology Yunnan University University of Chinese Academy of Sciences

Liquid chromatography coupled to tandem mass spectrometry(LC-MS/MS) is a highly specific and sensitive techniqueformeasuring *** this work,a method using thederivatization reaction combined withisotope dilutionLC-MS/MSanalysis to accurately quantify exogenous and endogenousglucose in plasma was *** mass spectrometer was carried outin multiple reaction monitoring mode(MRM) with electrospray ion source(ESI).Validation results indicated this method was robust,highly sensitive and significant improvement the accuracy of glucose *** curveshowed good linearity with correlation coefficient of R=0.9967 and the relative standard deviation(RSD%) calculated from triplicate analyses for each sample wasalways <2.5%.

关键词： LC-MS/MS endogenous and exogenous glucose MRM

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基于量子测度的两个可测集之间的干扰度

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陕西师范大学学报（自然科学版） 2017年第2期45卷 8-13页

作者：胡凯逢郭志华曹怀信陕西师范大学数学与信息科学学院陕西西安710119

在讨论量子测度某些性质的基础上,引入两个可测集关于量子测度的干扰度这一概念,并研究了它的一些性质。证明了任何量子测度都是n(≥3)级可加的;零测集和与其不相交的任何可测集之间的干扰度为零;一个量子测度处处具有零干扰度当且仅当... 详细信息

在讨论量子测度某些性质的基础上,引入两个可测集关于量子测度的干扰度这一概念,并研究了它的一些性质。证明了任何量子测度都是n(≥3)级可加的;零测集和与其不相交的任何可测集之间的干扰度为零;一个量子测度处处具有零干扰度当且仅当它是有限可加的;连续的量子测度处处具有零干扰度为当且仅当它是经典测度即可数可加的;计算了零测集的子集和与其不交的任何可测集的干扰度。

关键词：量子测度可测集干扰度

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混流式水轮机转轮适应性改造方法及效果分析

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水力发电学报 2023年第12期42卷 61-69页

作者：方创新高建国胡平良陈明胡凯锋孟龙湖北白莲河抽水蓄能有限公司水电分公司湖北黄冈438200 杭州径游发电设备有限公司杭州311255 中国水利水电科学研究院北京100038

对混流式水轮机转轮进行适应性改造,能改善机组对电站水文条件的匹配性,提高机组运行效率,增加机组出力,提升机组运行稳定性及安全性。本文以白莲河水电站3号机为具体应用案例,介绍了以提升机组效率及运行稳定性为主要目标的转轮优化方... 详细信息

对混流式水轮机转轮进行适应性改造,能改善机组对电站水文条件的匹配性,提高机组运行效率,增加机组出力,提升机组运行稳定性及安全性。本文以白莲河水电站3号机为具体应用案例,介绍了以提升机组效率及运行稳定性为主要目标的转轮优化方法,通过CFD计算对优化方案的能量特性及内部流场情况进行了数值分析预测,并通过现场试验对机组改造后的能量特性及运行稳定性进行了分析。能量特性方面,当机组出力在7~14.5 MW之间,改造后水轮机效率较改造前提升5%~8.84%,运行稳定性方面,机组在低部分负荷工况下,蜗壳进口和尾水锥管压力脉动幅值较改造前大幅降低,数值计算与现场测试均验证了优化方案的有效性。

关键词：混流式水轮机适应性改造数值计算现场测试机组稳定性

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