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Abstract

Using a collection of papers gathered from the Web of Science, and defining disciplines by the JCR classification, this paper compares the disciplinary structure of the G7 countries (representing high S&T level countries) and the BRIC countries (representing fast breaking countries in S&T) by using bibliometric methods. It discusses the similarity and the balance of their disciplinary structure. We found that: (1) High S&T level countries have a similar national disciplinary structure; (2) In recent years the disciplinary structure of the BRIC countries has become more and more similar to that of the G7 countries; (3) The disciplinary structure of the G7 countries is more balanced than that of the BRIC countries (4) In the G7 countries more emphasis goes to the life sciences, while BRIC countries focus on physics, chemistry, mathematics and engineering.

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This study aims at establishing a thin-layer chromatographic (TLC) scanning method for the determination of three alkaloids in Sophora alopecuroides and preliminary screening of antioxidant active components in S. alopecuroides with TLC—bioautography technology. The alkaloids in S. alopecuroides were identified by silica gel thin-layer chromatography; the expansion agent was toluene— acetone—methanol—ammonia—water (8:3:0.2:0.5:8), and the chromogenic agent was modified bismuth potassium iodide solution, sophoridine, matrine, and sophocarpine in S. alopecuroides by TLC scanning at 500 nm. The linear ranges were 0.4152–2.4912 μg for sophordine, 0.4245–2.5470 μg for matrine, and 0.4101– 2.4606 μg for sophocarpine, with correlation coefficients of 0.9939, 0.9956, and 0.9975. Ultraviolet (UV) method was used to determine the total scavenging activity of the 2,2-diphenyl-1-picrylhdrazyl (DPPH) free radical. The best TLC identification condition was selected, and the antioxidant activity of DPPH was screened with the color. DPPH tests indicated that IC50 of S. alopecuroides was 0.40 mg mL−1. The TLC—bioautography technology showed the alkaloids in the purple background, and a white spot was not evident. Precision, accuracy, and repeatability of the TLC scanning method were evaluated, and the results were in accordance with the requirements of methodology validation. S. alopecuroides exhibits certain antioxidant activity, but the three alkaloids do not exhibit an evident antioxidant effect, and the unknown components of S. alopecuroides show weak antioxidant effect. The specific components need further studies.

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Acta Chromatographica
Authors: Yun Zhou, Guifeng Huang, Xiaolan Li, Feng Chen, Hong Liu, Ying Yang, Zhong Fan, Jinghui Jiang, and Jun Yang

A credible method for determination of the aglycon moieties of glycosidically bound aroma compounds in Flos Chrysanthemi by comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC × GC–TOFMS) has been proposed. The aglycon moieties of glycosidically bound aroma compounds were isolated using methyl-tert-butyl ether (MTBE) extraction following enzymatic hydrolysis. The GC × GC–TOFMS analysis was performed to comprehensively identify different forms of the released aroma components in Flos Chrysanthemi. The result shows that the limit of detection of the released aglycon moieties ranged from 0.3 to 3.1 ng/mL, the recovery of the released 1-octanol was better than 98.3%, and the intra-day and inter-day precisions of this method were 0.2 to 8.9% and 1.3 to 9.1%, respectively. The proposed method was applied to the analysis of four types of Flos Chrysanthemi (Chuju, Boju, Hangju, and Gongju). A total of 60 aglycon moieties of interest were identified in the four types of Flos Chrysanthemi. These aglycones mainly consisted of aliphatic, aromatic, monoterpene, C13-norisoprenoids, and miscellaneous compounds.

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