Liquid Chromatography Quadrupole Time-Of-Flight Tandem Mass Spectrometry for Selective Determination of Usnic Acid and Application in Pharmacokinetic Study

Fang, Minfeng,Wang, Hui,Wu, Yang,Wang, Qilin,Zhao, Xinfeng,Zheng, Xiaohui,Wang, Shixiang,Zhao, Guifang Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.6

A rapid and sensitive method for determining usnic acid of Lethariella cladonioides in rat was established using high performance liquid chromatography (HPLC) quadrupole time-of-flight (QTOF) tandem mass (MS/MS). Rat plasma was pretreated by mixture of acetonitrile and chloroform to precipitate plasma proteins. Chromatographic separation was achieved on a column ($50{\times}2.1$ mm, $5{\mu}m$) with a mobile phase consisting of water (containing $5{\times}10^{-3}$ M ammonium formate, pH was adjusted to 3.0 with formic acid) and acetonitrile (20:80, v/v) at a flow rate of 0.3 mL/min. A tandem mass spectrometric detection with an electrospray ionization (ESI) interface was conducted via collision induced dissociation (CID) under negative ionization mode. The MS/MS transitions monitored were m/z 343.0448 ${\rightarrow}$ m/z 313.2017 for usnic acid and m/z 153.1024 ${\rightarrow}$ m/z 136.2136 for protocatechuic acid (internal standard). The linear range was calculated to be 2.0-160.0 ng/mL with a detection limit of 3.0 pg/mL. The inter- and intra-day accuracy and precision were within ${\pm}7.0%$. Pharmacokinetic study showed that the apartment of usnic acid in vivo confirmed to be a two compartment open model. The method was fully valid and will probably be an alternative for pharmacokinetic study of usnic acid.

Liquid Chromatography Quadrupole Time-Of-Flight Tandem Mass Spectrometry for Selective Determination of Usnic Acid and Application in Pharmacokinetic Study

Minfeng Fang,Hui Wang,Yang Wu,Qilin Wang,Xinfeng Zhao,Xiao-Hui Zheng,Shixiang Wang,Guifang Zhao 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.6

A rapid and sensitive method for determining usnic acid of Lethariella cladonioides in rat was established using high performance liquid chromatography (HPLC) quadrupole time-of-flight (QTOF) tandem mass (MS/MS). Rat plasma was pretreated by mixture of acetonitrile and chloroform to precipitate plasma proteins. Chromatographic separation was achieved on a column (50 × 2.1 mm, 5 μm) with a mobile phase consisting of water (containing 5 × 10−3 M ammonium formate, pH was adjusted to 3.0 with formic acid) and acetonitrile (20:80, v/v) at a flow rate of 0.3 mL/min. A tandem mass spectrometric detection with an electrospray ionization (ESI) interface was conducted via collision induced dissociation (CID) under negative ionization mode. The MS/MS transitions monitored were m/z 343.0448 → m/z 313.2017 for usnic acid and m/z 153.1024 → m/z 136.2136 for protocatechuic acid (internal standard). The linear range was calculated to be 2.0-160.0 ng/mL with a detection limit of 3.0 pg/mL. The inter- and intra-day accuracy and precision were within ± 7.0%. Pharmacokinetic study showed that the apartment of usnic acid in vivo confirmed to be a two compartment open model. The method was fully valid and will probably be an alternative for pharmacokinetic study of usnic acid.

A Study on Factors Influencing the Accuracy Evaluation of Dimensional X-Ray Computed Tomography with Multi-sphere Standards

Shixiang Su,Ning Dai,Xiaosheng Cheng,Xin Zhou,Lei Wang,Herminso Villarraga-Gómez 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.4

Industrial X-ray Computed Tomography (XCT) is one of the available choices for measuring parts’ internal and externalgeometries. However, there are still several challenges that limit the current XCT technologies from being widely spread asa dimensional metrology tool. In the study presented in this paper, multi-sphere standards were developed and used for theevaluation of the accuracy of dimensional measurements performed with an open-ended 450 kV XCT system of 0.4 mmfocal spot. Normally, the multi-sphere standard refers to a combination of several ball rods of various heights, where a ‘ballrod’ is understood as a ruby sphere mounted on a rod that is usually made of carbon fi ber or ceramic. The main purpose wasto determine if the rod’s material, the spatial distribution of the ruby spheres, and/or the selection of test lengths (i.e., thecenter-to-center distance between two ruby spheres) infl uence the determination of the maximum permissible sphere distanceerror ( MPE SD ) attributable to XCT data. The experimental data suggested ceramic is more suitable as a rod material thancarbon fi ber, and also, the spatial distribution of the ruby spheres has no obvious infl uence on the accuracy evaluation ofdimensional measurements. However, the selection of test lengths will signifi cantly aff ect the accuracy evaluation results. In particular, the results of dimensional measurements showed that the evaluation of the MPE SD with multi-sphere standardsfor the XCT system used in this study can be expressed as MPE SD = ± (159 + L/800) μm.

Morphological and ultrastructural characterization of the alimentary canal in larvae of Streltzoviella insularis (Staudinger) (Lepidoptera: Cossidae)

Xiuji Wang,Hao LU,Yuying SHAO,Shixiang ZONG 한국곤충학회 2018 Entomological Research Vol.48 No.4

Streltzoviella insularis (Staudinger) is an important tree‐boring pest, that primarily damages Sophora japonica (Linnaeus) and Ginkgo biloba (Linnaeus), as well as other common species, at great economic cost to the urban landscape construction industry in China. In the present study, the alimentary canal morphology of S. insularis was observed using light microscopy, and its ultrastructure was investigated by scanning and transmission electron microscopy. The foregut of S. insularis can be divided into the pharynx, esophagus, crop, proventriculus, and cardiac valve. The well‐developed crop forms the longest section of the foregut. It is able to store large amounts of food and is lined with a monolayer of epithelial cells. Many sclerotized microspines occur on the surface of the anterior intima and there are dense spines on the posterior intima of the proventriculus. Epithelial cells of the midgut include columnar cells, goblet cells, and regenerative cells, but endocrine cells are absent. The hindgut consists of the pyloric valve, ileum, and rectum. There is no clear distinction between the ileum and colon. The intima surface of the pyloric valve carries many microspines, whereas the intestinal wall of the rectum is thin with well‐developed rectal pads. The rectal epithelial cells form a squamous monolayer. A cryptonephric excretory system is located in the hindgut. There are six spiral Malpighian tubules, in which a cellular layer on a basement membrane encloses a lumen. These results will provide the basis for further studies of the structure and function in S. insularis larvae.

cDNA cloning and expression analysis of the juvenile hormone acid methyltransferase from seabuckthorn carpenterworm, Holcocerus hippophaecolus (Lepidoptera: Cossidae)

Shuo Zhang,Yu WANG,Jiao ZHOU,Juan Li,Shixiang ZONG,You-qing Luo,Qiang WENG 한국곤충학회 2016 Entomological Research Vol.46 No.1

In this study, we report the cDNA cloning and sequence determination of Hh‐JHAMT from the seabuckthorn carpenterworm, Holcocerus hippophaecolus, by using rapid amplification of cDNA ends. The full‐length cDNA of putative Hh‐JHAMT was 1659 bp and contained a highly conserved Motif I, SAM motif I, which showed that Hh‐JHAMT like enzyme was a member of SAM‐dependent MTases. Moreover, putative Hh‐JHAMT had high homology to the other members of the JHAMT peptide family: 59% with Spodoptera litura, 54% with Bombyx mori and 54% with Helicoverpa armigera. Multiple alignments and phylogenetic analysis revealed that Hh‐JHAMT was closely related to JHAMT from Lepidoptera. Real‐time quantitative PCR experiments showed that Hh‐JHAMT mRNA expression was highest in the corpora allata (CA) complex, and was also detected at high levels during earlier larval and adult stages. The JHAMT mRNA level gradually declined during larval development, and the lowest amount of expression was observed in the pupal stage, while it increased to a higher level during adult stages. The pattern of Hh‐JHAMT expression was similar to the mode of JH biosynthesis. These results provided information concerning molecular characteristics of Hh‐JHAMT, whose expression profile suggests that the Hh‐JHAMT gene might be changed with larval development, metamorphosis and adult reproduction of the H. hippophaecolus.

Lithology and oil-bearing properties of tight sandstone reservoirs: Chang 7 member of Upper Triassic Yanchang Formation, southwestern Ordos Basin, China

Congjun Feng,Hua Yang,Renhai Pu,Yaning Wang,Daxing Wang,Xiaowei Liang,Mengbo Zhang,Yougen Huang,Shixiang Fei 한국지질과학협의회 2017 Geosciences Journal Vol.21 No.2

Using core, well logging, geological analysis, production, and test data, this study characterizes a method of well logging for identifying lithology, oil or water layers, and thickness of oil layers of tight sandstone reservoir in the Chang 7 member of the Upper Triassic Yanchang Formation, southwestern Ordos Basin, China. This reservoir consists of two rock types: fine sandstone and siltstone. The fine sandstone has distinct oil traces and flecks, which strongly indicate the presence of oil, and this rock is therefore the superior reservoir. The siltstone exhibits essentially no oil shows and thus is an unproductive layer. A method of density and neutron curve normalization and overlay was used to identify the tight fine sandstone, tight siltstone, mudstone, and shale. The criteria for identifying the tight fine sandstone are a natural gamma value of less than 93 API (American Petroleum Institute units) and a difference between the normalized curves exceeding 0.05. A resistivity-porosity plot was used to identify oil or water layers relatively effectively. The criteria for identifying the tight oil layers are (1) a resistivity exceeding 28 Ω·m and a porosity exceeding 9.5% or (2) a resistivity between 20 and 28 Ω·m, a porosity exceeding 9.5%, and an oil saturation exceeding 65%. Based on the lithologic identification via normalization and overlay of the density and neutron curves and the criteria for distinguishing the tight oil layers, the thickness of the tight fine sandstone oil reservoir was accurately determined by overlaying the normalized difference curve on the resistivity curve.