• Title/Summary/Keyword: Chemical profiling

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Reduction of Ambiguity in Phosphorylation-site Localization in Large-scale Phosphopeptide Profiling by Data Filter using Unique Mass Class Information

  • Madar, Inamul Hasan;Back, Seunghoon;Mun, Dong-Gi;Kim, Hokeun;Jung, Jae Hun;Kim, Kwang Pyo;Lee, Sang-Won
    • Bulletin of the Korean Chemical Society
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    • v.35 no.3
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    • pp.845-850
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    • 2014
  • The rapid development of shotgun proteomics is paving the way for extensive proteome profiling, while providing extensive information on various post translational modifications (PTMs) that occur to a proteome of interest. For example, the current phosphoproteomic methods can yield more than 10,000 phosphopeptides identified from a proteome sample. Despite these developments, it remains a challenging issue to pinpoint the true phosphorylation sites, especially when multiple sites are possible for phosphorylation in the peptides. We developed the Phospho-UMC filter, which is a simple method of localizing the site of phosphorylation using unique mass classes (UMCs) information to differentiate phosphopeptides with different phosphorylation sites and increase the confidence in phosphorylation site localization. The method was applied to large scale phosphopeptide profiling data and was demonstrated to be effective in the reducing ambiguity associated with the tandem mass spectrometric data analysis of phosphopeptides.

UPLC-Q-TOF-MS/MS Analysis for Steaming Times-dependent Profiling of Steamed Panax quinquefolius and Its Ginsenosides Transformations Induced by Repetitious Steaming

  • Sun, Bai-Shen;Xu, Ming-Yang;Li, Zheng;Wang, Yi-Bo;Sung, Chang-Keun
    • Journal of Ginseng Research
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    • v.36 no.3
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    • pp.277-290
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    • 2012
  • The metabolic profiles of Panax quinquefolius and its associated therapeutic values are critically affected by the repetitious steaming times. The times-dependent steaming effect of P. quinquefolius is not well-characterized and there is also no official guideline on its times of steaming. In this paper, a UPLC-Q-TOF-MS/MS method was developed for the qualitative profiling of multi-parametric metabolic changes of raw P. quinquefolius during the repetitious steaming process. Our method was successful in discriminating the differentially multi-steamed herbs. Meantime, the repetitious steaming-inducing chemical transformations in the preparation of black American ginseng (American ginseng that was subjected to 9 cycles of steaming treatment) were evaluated by this UPLC-Q-TOF-MS/MS based chemical profiling method. Under the optimized UPLC-Q-TOF-MS/MS conditions, 29 major ginsenosides were unambiguously identified and/or tentatively assigned in both raw and multi-steamed P. quinquefolius within 19 min, among them 18 ginsenosides were detected to be newly generated during the preparatory process of black American ginseng. The mechanisms involved were further deduced to be hydrolysis, dehydration, decarboxylation and addition reactions of the original ginsenosides in raw P. quinquefolius through analyzing mimic 9 cycles of steaming extracts of 14 pure reference ginsenosides. Our novel steaming times-dependent metabolic profiling approach represents the paradigm shift in the global quality control of multi-steamed P. quinquefolius products.

Reflow Profiling The Benefits of Implementing a Ramp-to-Spike Profile

  • AIM
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2000.04a
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    • pp.17-17
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    • 2000
  • The issue of reflow profiling continues to be a complex topic. The pains often associated with profiling can be reduced greatly if certain guidelines are followed and if there is a strong understanding of the variables that can be encountered during the reflow process. This paper shall discuss the appropriate guidelines and trouble shooting methods for reflow profiling, and in particular shall focus upon the benefits of implementing the linear ramp-to-spike profile. Delta T(T) is defined as the variation of temperature found on an assembly during the reflow process. Too large of a T can result in soldering defects, so to combat T a Ramp-Soak-Spike(RSS) reflow profile often is utilized. However, when using a newer-style reflow oven, the T often is minimized or eliminated, thus, the soak zone of the reflow profile becomes an unnecessary step. Because of this, the implementation of a linear Ramp-To-Spike(RTS) reflow profile should be considered. Benefits such as reduced energy costs, reduced solder defects, increased efficiency, improved wetting, and a simplification of the reflow profile process may be experienced when using the RTS profile. Included in this paper are the suggested process parameters for setting up the RSS and RTS profiles and the chemical and metallurgical reactions that occur at each set point of these profiles. The paper concludes with a discussion and pictures of several profile-related defects. Each of these defects is described, analyzed, and instructions are given for troublshooting these defects.

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Structure and chemical composition of $CsB_{3}O_{5}$ (CBO) optical surface

  • V.V. Atuchin;V.G. Kesler;L.D. Pokrovsky;N. Yu. Maklakova;M. Yoshimura;N. Ushiyama;T. Matsui;K. Kamimura;Y. Mori;T. Sasaki
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.13 no.1
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    • pp.19-23
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    • 2003
  • Polished surface of $CsB_{3}O_{5}$ (CBO) has been observed by reflection high energy electron diffraction (RHEED) and X-ray photoelectron spectroscopy (XPS). For comparison, electronic properties of CBO powder have been studied by XPS. It has been found that the crystal surface is covered by thick amorphous layer with chemical composition closely related to that of CBO. Great enrichment of top surface by cesium, ~30 % in reference to the bulk of the modified layer, has been displayed by depth profiling.

A comparative study on chemical composition of total saponins extracted from fermented and white ginseng under the effect of macrophage phagocytotic function

  • Xiao, Dan;Xiu, Yang;Yue, Hao;Sun, Xiuli;Zhao, Huanxi;Liu, Shuying
    • Journal of Ginseng Research
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    • v.41 no.3
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    • pp.379-385
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    • 2017
  • In this study, white ginseng was used as the raw material, which was fermented with Paecilomyces hepiali through solid culture medium, to produce ginsenosides with modified chemical composition. The characteristic chemical markers of the products thus produced were investigated using rapid resolution liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (RRLC-QTOF-MS). Chemical profiling data were obtained, which were then subjected to multivariate statistical analysis for the systematic comparison of active ingredients in white ginseng and fermented ginseng to understand the beneficial properties of ginsenoside metabolites. In addition, the effects of these components on biological activity were investigated to understand the improvements in the phagocytic function of macrophages in zebrafish. According to the established RRLC-QTOF-MS chemical profiling, the contents in ginsenosides of high molecular weight, especially malonylated protopanaxadiol ginsenosides, were slightly reduced due to the fermentation, which were hydrolyzed into rare and minor ginsenosides. Moreover, the facilitation of macrophage phagocytic function in zebrafish following treatment with different ginseng extracts confirmed that the fermented ginseng is superior to white ginseng. Our results prove that there is a profound change in chemical constituents of ginsenosides during the fermentation process, which has a significant effect on the biological activity of these compounds.