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351.
Development of simultaneous analysis of tryptophan metabolites in serum and gastric juice – an investigation towards establishing a biomarker test for gastric cancer diagnosis 下载免费PDF全文
Jong Min Choi Won Sang Park Kyo Young Song Hwa Jeong Lee Byung Hwa Jung 《Biomedical chromatography : BMC》2016,30(12):1963-1974
To evaluate changes in tryptophan metabolism and discover diagnostic biomarkers for gastric cancer, a quantitative method was developed for tryptophan and its seven metabolites (indole‐3‐lactic acid, anthranilic acid, serotonin, nicotinic acid, kynurenic acid, kynurenine and 3‐indoxyl sulfate) in both human serum and gastric juice using liquid chromatography–tandem mass spectrometry (LC–MS/MS). Serum and gastric juice were prepared with a simple protein precipitation using aqueous 0.1% formic acid and acetonitrile. As a result, it was found that the kynurenine pathway of tryptophan metabolism was activated in gastric cancer and that the metabolic ratio of kynurenine/tryptophan, which reflects the enzyme activity of indoleamine‐2,3‐dioxygenase, was associated with the observed metabolic changes. Finally, the investigation of tryptophan metabolites, especially kynurenic acid, in serum and gastric juice might serve as biomarkers for gastric cancer. The findings in this study provide critical information of tryptophan metabolism which can be applied to a serum‐based diagnostic test for gastric cancer. 相似文献
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Thermal stability of ester linkage in the presence of 1,2,3‐Triazole moiety generated by click reaction 下载免费PDF全文
Kyu Seong Lee So Yeong Park Hong Chul Moon Jin Kon Kim 《Journal of polymer science. Part A, Polymer chemistry》2017,55(3):427-436
The copper(I)‐catalyzed alkyne‐azide cycloaddition (CuAAC), so‐called “click” reaction, is one of most useful synthetic strategies to connect two polymer chains. 1,2,3‐Triazole ring (TA) produced by the click reaction has good thermal and chemical stability. However, we observed that block copolymers synthesized by the click reaction showed thermal degradation to give homopolymers when they are thermally annealed at high temperature, which is required for obtaining equilibrium microdomain structure. To investigate the origin of thermal instability of block copolymers, we synthesized model polystyrenes (PSs) using systematically designed bi‐functional atom transfer radical polymerization (ATRP) initiators containing TA. PS including both ester and TA groups showed thermal decomposition at relatively low temperature (e.g., 140 °C). MALDI‐TOF analysis clearly demonstrated that the cleavage site is the ester group adjacent to TA. We also found that the bromine group located at the polymer chain end plays an important role in pyrolysis of ester groups at low temperature. The pyrolysis occurs by syn‐elimination of the ester group. This result implies that the phase behavior of block copolymer synthesized by click reaction should be carefully investigated when high temperature thermal annealing is required. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 427–436 相似文献
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Kim Gun Gyun Lee Jun Young Choi Pyeong Seok Vyas Chirag K. Yang Seung Dae Hur Min Gu Park Jeong Hoon 《Journal of Radioanalytical and Nuclear Chemistry》2018,316(3):1099-1106
Journal of Radioanalytical and Nuclear Chemistry - Accumulation of triphenylphosphonium (TPP) is normally observed in the mitochondria from the extracellular spaces due to the high difference in... 相似文献
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Isothermal-crystallization kinetics and spherulite growth of aliphatic polyketone/polyamide-6 blends
In this research,the morphologies,isothermal-crystallization kinetics,and spherulite growth of aliphatic polyketone/polyamide-6 blends were studied.A single glass-transition temperature (Tg) was determined,and the composition dependence of Tg for these blends was well described by the Kwei equation.The strong intermolecular interaction between the two polymer components was confirmed by melting-point depression.The isothermal-crystallization kinetics were analyzed on the basis of the Avrami approach.A linear increase in the radii of the spherulites with time was observed for all compositions.All the spherulites continued to grow at nearly identical growth rates.With increasing polyamide-6 content,the size of the spherulites in the polyketone/polyamide-6 blends gradually decreased,and the number of spherulites in the blends increased. 相似文献