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81.
Screening and analysis of an antineoplastic compound in Rhizoma Chuanxiong by means of in vitro metabolism and HPLC-MS 总被引:1,自引:0,他引:1
A new screening and analysis method that combines in vitro metabolism with high-performance liquid chromatography-mass spectrometry
(HPLC-MS) was developed for the screening and analysis of an antineoplastic compound, coniferyl ferulate, which is present
in the rhizome of Rhizoma Chuanxiong. Infrared (IR), ultraviolet visible spectroscopy (UV-Vis), nuclear magnetic resonance (NMR) and element analysis were used
to identify the molecular structure of coniferyl ferulate. The quantitative analysis of coniferyl ferulate in different extracts
of Rhizoma Chuanxiong was carried out, and the metabolism of coniferyl ferulate was investigated by in vitro incubation with rat liver homogenate.
The metabolite of coniferyl ferulate, ferulic acid ethyl ester, was identified by HPLC-MS, UV-Vis and IR. In addition, antineoplastic
activities of coniferyl ferulate and ferulic acid ethyl ester were detected by the MTT assay. The observed inhibition rate
of coniferyl ferulate on the activity of HeLa cells was over 80% at 5.4 ng μl−1. However, its metabolite, ferulic acid ethyl ester, showed no antineoplastic activity in vitro.
相似文献
82.
近年来,不少文章讨论到一种类型的共形平坦空间,即所谓“拟常曲率空间”,得到了关于这类空间的一些性质。然而,也出现了一些概念上混乱的情形,导至一些人在引用时或作某些判断时有所失误。本文目的一方面试图说清这些问题,另一方面也明确地界定此类空间的范围,给予一个完全的分类。为了不进行一些非普遍性问题的讨论,本文所论空间的维数nn>4,并且在没有特别说明的情况下,所有出现的指标取值范围都是1,2,…,n。 相似文献
83.
We propose a joint nonlinear electrical equalization approach in coherent optical discrete-Fourier-transform spread orthogonal-frequency-division-multiplexing(DFT-spread-OFDM) systems with polarization division multiplexing(PDM).This method is based on an adaptive Volterra series expansion for nonlinear distortions of two orthogonal polarizations.The nonlinear electrical equalization is validated through numerical simulation of 100-Gb/s quadrature phase shift keying and 200-Gb/s 16 quadrature amplitude modulation PDM DFT-spread-OFDM systems. 相似文献
84.
85.
Qianqian Liu Xiaoyu Yang Meng Wang Die Liu Mingzhao Chen Tun Wu Zhiyuan Jiang Pingshan Wang 《Tetrahedron》2019,75(16):2400-2405
A novel family of metallocycles was constructed by a one-pot self-assembly of three analogous bis(terpyridine) ligand monomers L1-L3, having different bent angles, with metal ions (Zn2+ or Cd2+). The dibenzo[b,d]thiophene-containing ligand L3 assembled with the metal ions to form a single trimer, whereas the dibenzo[b,d]furan-containing ligand L2 and dibenzo[b,d]carbazole-containing ligand L1 formed a mixture of trimers and tetramers. Heteroatoms (N, O, S) significantly contributed to the molecular size of the assemblies, owing to the bent angle of the bis-terpyridines ligands. 相似文献
86.
Zhiyuan He Pai Liu Shizhong Zhang Jie Yan Mengni Wang Zhengxu Cai Jianjun Wang Yuping Dong 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(12):3874-3877
Cryosurgery has attracted much attention for the treatment of tumors owing to its clear advantages. However, determining the volume of frozen tissues in real‐time remains a challenge, which greatly lowers the therapeutic efficacy of cryosurgery and hinders its broad application for the treatment of cancers. Herein, we report a freezing‐induced turn‐on strategy for the selective real‐time imaging of frozen cancer cells. As a type of aggregation‐induced emission (AIE) fluorogen, TABD‐Py molecules interact specifically with ice crystals and form aggregates at the ice/water interface. Consequently, bright fluorescent emission appears upon freezing. TABD‐Py molecules are enriched mostly in the cancer cells and exhibit high biocompatibility as well as low cytotoxicity; therefore, a freezing‐induced turn‐on imaging modality for cryosurgery is developed, which will certainly maximize the therapeutic efficacy of cryosurgery in treating tumors. 相似文献
87.
High-temperature (700–900 ℃) steam electrolysis based on solid oxide electrolysis cells (SOECs) is valuable as an efficient and clean path for large-scale hydrogen production with nearly zero carbon emissions, compared with the traditional paths of steam methane reforming or coal gasification. The operation parameters, in particular the feeding gas composition and pressure, significantly affect the performance of the electrolysis cell. In this study, a computational fluid dynamics model of an SOEC is built to predict the electrochemical performance of the cell with different sweep gases on the oxygen electrode. Sweep gases with different oxygen partial pressures between 1.01 × 103 and 1.0 × 105 Pa are fed to the oxygen electrode of the cell, and the influence of the oxygen partial pressure on the chemical equilibrium and kinetic reactions of the SOECs is analyzed. It is shown that the rate of increase of the reversible potential is inversely proportional to the oxygen partial pressure. Regarding the overpotentials caused by the ohmic, activation, and concentration polarization, the results vary with the reversible potential. The Ohmic overpotential is constant under different operating conditions. The activation and concentration overpotentials at the hydrogen electrode are also steady over the entire oxygen partial pressure range. The oxygen partial pressure has the largest effect on the activation and concentration overpotentials on the oxygen electrode side, both of which decrease sharply with increasing oxygen partial pressure. Owing to the combined effects of the reversible potential and polarization overpotentials, the total electrolysis voltage is nonlinear. At low current density, the electrolysis cell shows better performance at low oxygen partial pressure, whereas the performance improves with increasing oxygen partial pressure at high current density. Thus, at low current density, the best sweep gas should be an oxygen-deficient gas such as nitrogen, CO2, or steam. Steam is the most promising because it is easy to separate the steam from the by-product oxygen in the tail gas, provided that the oxygen electrode is humidity-tolerant. However, at high current density, it is best to use pure oxygen as the sweep gas to reduce the electric energy consumption in the steam electrolysis process. The effects of the oxygen partial pressure on the power density and coefficient of performance of the SOEC are also discussed. At low current density, the electrical power demand is constant, and the efficiency decreases with growing oxygen partial pressure, whereas at high current density, the electrical power demand drops, and the efficiency increases. 相似文献
88.
89.
Ruo Li Zhiyuan Sun Zhijian Yang 《Numerical Methods for Partial Differential Equations》2020,36(4):756-771
A discontinuous Galerkin method by patch reconstruction is proposed for Stokes flows. A locally divergence-free reconstruction space is employed as the approximation space, and the interior penalty method is adopted which imposes the normal component penalty terms to cancel out the pressure term. Consequently, the Stokes equation can be solved as an elliptic system instead of a saddle-point problem due to such weak form. The number of degree of freedoms of our method is the same as the number of elements in the mesh for different order of accuracy. The error estimations of the proposed method are given in a classical style, which are then verified by some numerical examples. 相似文献
90.
Inside Back Cover: Developing Conjugated Polymers with High Electron Affinity by Replacing a CC Unit with a B←N Unit (Angew. Chem. Int. Ed. 12/2015)
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