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11.
Xiang Cui Yu‐meng Shen Shu Jiang Da‐wei Qian Er‐xin Shang Zhen‐hua Zhu Jin‐ao Duan 《Journal of separation science》2019,42(8):1520-1527
In this study, a rapid and highly sensitive ultra high performance liquid chromatography with triple quadrupole mass spectrometry method with the mobile phase of acetonitrile and 0.1% aqueous formic acid was established and successfully applied to comparatively analyze main active components after their compatibility. Besides, the effects of Scutellariae Radix, Coptidis Rhizoma and combined extracts on type 2 diabetic rats induced by high‐fat diet along with low dose of streptozocin were investigated. Under the optimized chromatographic conditions, good separation of seven target components was achieved within 12 min. All calibration curves exhibited good linearity (R2 ≥ 0.999). The relative standard deviation of precision, repeatability and stability varied from 0.69 to 2.23, 0.98 to 2.56, and 0.92 to 2.57%, respectively. The recovery ranged from 91.11 to 105.35%. The contents of seven active components were notably reduced after compatibility; however, the hypoglycemic effect of combined extracts was stronger than single drug by decreasing the activities of fructose‐1,6‐bisphosphatase, glucose 6‐phosphatase, phosphoenolpyruvate carboxykinase and increasing the activities of glucokinase, phosphofructokinase, pyruvate kinase. Accordingly, the established analytical method was accurate and sensitive enough for quantitative evaluation of seven investigated compounds. Moreover, the combined extract had definite effects on type 2 diabetes through multiple components against multiple targets. 相似文献
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Meccanica - This paper introduces an analytical approach to optimize the textured bearing with cavitation to improve the load support. For this purpose, a grooved parallel slider bearing is... 相似文献
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建立一种利用高效液相色谱结合荧光检测器准确测定2-噁唑烷酮含量的方法。样品中的2-噁唑烷酮和占吨氢醇在60℃的条件下衍生70 min后,直接进样分析。采用月旭XB-C18色谱柱,流动相为0.02 mol/L乙酸钠水溶液和乙腈,检测器波长为λex=213 nm,λem=308 nm,流速1.0 mL/min,柱温35℃的条件下。2-噁唑烷酮浓度在0.5~50.0mg/mL时,线性关系良好(R2=0.9995),检测限和定量限分别为0.005 mg/L、0.016 mg/L。该方法准确、灵敏、快速,适用于2-噁唑烷酮含量的检测。 相似文献
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Rational Design of an Ultrasensitive and Highly Selective Chemodosimeter by a Dual Quenching Mechanism for Cysteine Based on a Facile Michael‐Transcyclization Cascade Reaction 下载免费PDF全文
Xiangmin Li Yongjun Zheng Hongjuan Tong Rui Qian Dr. Lin Zhou Prof. Dr. Guixia Liu Prof. Dr. Yun Tang Prof. Dr. Hao Li Prof. Dr. Kaiyan Lou Prof. Dr. Wei Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(27):9247-9256
Differentiation of biologically important thiols, such as cysteine (Cys), homocysteine (Hcy), and glutathione (GSH) is still a challenging task. Herein, we present a novel fluorescent chemodosimeter capable of selectively detecting Cys over other biothiols including Hcy and GSH and other amino acids by a facile thiol‐Michael addition/transcyclization rearrangement cascade click process. The unique transcyclization step is critical for the selectivity as a result of the kinetically favorable formation of a six‐membered ring with the Cys Michael adduct. Moreover, the probe adopts a distinctive dual quenching mechanism—photoinduced electron transfer (PET) and photoinduced intramolecular charge transfer (ICT) to deliver a drastic turn‐on fluorescence response only at the Cys‐selective transcylization step. The judicious selection of strong electron‐withdrawing naphthalimide fluorophore with maleimide group enhances the electrophilicity and thus reactivity for the cascade process leading to fast detection and ultrasensitivity with a detection limit of 2.0 nm (S/N=3). The probe has demonstrated its practical utility potential in Cys imaging in live cells. 相似文献
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A new spectral problem is proposed, and nonlinear differential equations of the corresponding hierarchy are obtained. With the help of the nonlinearization appr... 相似文献
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