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71.
Multi‐analysis strategy for metabolism of Andrographis paniculata in rat using liquid chromatography/quadrupole time‐of‐flight mass spectrometry 下载免费PDF全文
Wenlan Li Xiangming Sun Ying Xu Xuezhi Wang Jing Bai Yubin Ji 《Biomedical chromatography : BMC》2015,29(7):1016-1026
Compared with chemical drugs, it is a huge challenge to identify active ingredients of multicomponent traditional Chinese medicine (TCM). For most TCMs, metabolism investigation of absorbed constituents is a feasible way to clarify the active material basis. Although Andrographis paniculata (AP) has been extensively researched by domestic and foreign scholars, its metabolism has seldom been fully addressed to date. In this paper, high‐performance liquid chromatography/quadrupole time‐of‐flight mass spectrometry was applied to analysis and characterization of AP metabolism in rat urine and feces samples after oral administration of ethanol extract. The differences in metabolites and metabolic pathways between the two biological samples were further compared. The chemical structures of 20 components were tentatively identified from drug‐treated biological samples, including six prototype components and 14 metabolites, which underwent such main metabolic pathways as hydrolyzation, hydrogenation, dehydroxylation, deoxygenation, methylation, glucuronidation, sulfonation and sulfation. Two co‐existing components were found in urine and feces samples, suggesting that some ingredients' metabolic processes were not unique. This study provides a comprehensive report on the metabolism of AP in rats, which will be helpful for understanding its mechanism. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
72.
Jinyun Zheng Xiao Li Yujian Yu Xiangming Feng Yufen Zhao 《Journal of Thermal Analysis and Calorimetry》2014,117(1):319-324
The novel phosphate derivatives of phosphaphenanthrene with high-density phosphorus were synthesized and used as flame retardant additives for Li-ion batteries. The structures of compounds were characterized by 1H NMR, 13C NMR, 31P NMR, FT-IR, and HR-MS. The excellent thermal stability of compounds was ascertained by thermogravimetric analysis and differential scanning calorimetry. The compounds were added to conventional electrolytes as flame retardant additives and evaluated their ionic conductivity, electrochemical stability, self-extinguishing properties, and combustion performance. The results showed that the compound containing higher phosphorus content has efficient flame retardant properties. 相似文献
73.
设ρ(M)是微分流形M上的左四元数矢丛,文中给出ρ(M)的辛Pontryagin示性类和辛Pontryagin示性式的定义,并给出说明它们之间的联系的积分公式。 相似文献
74.
DEGREE OF COPOSITIVE POLYNOMIAL APPROXIMATION 总被引:2,自引:0,他引:2
Yu Xiangming 《数学年刊B辑(英文版)》1989,10(3):409-415
Denoteby _n(f) the degree of copositive approximation to f(x) by polynomials of degree≤n. For function f(x) ∈ C~k[-1, 1] which alternates in sign finitely many timesin [-1, 1], the author obtains the following Jackson type estimates_n(f)≤Cn~(-k)w(f~(k), 1/n)foa any positive integer k. 相似文献
75.
Jiaoyang Li Li Wang Yumei Ren Yong Zhang Youfu Wang Aiguo Hu Xiangming He 《Ionics》2016,22(2):167-172
A distinctive structure of carbon materials for Li-ion batteries is proposed for the preparation of red phosphorus-carbon composites. The slit-shaped porous carbon is observed with aggregation of plate-like particles, whose isotherm belongs to the H3 of type IV. The density functional theory (DFT) method reveals the presence of micro-mesopores in the 0.5–5 nm size range. The unique size distribution plays an important role in adsorbing phosphorus and electrochemical performance. The phosphorus-slit-shaped porous carbon composite shows initial capacity of 2588 mAh g?1, reversible capacity of 1359 mAh g?1 at a current density of 100 mA g?1. It shows an excellent coulombic efficiency of ~99 % after 50 cycles. 相似文献
76.
A new simple method for the synthesis of alpha-glycosyl thiols is described. Ring-opening of 1,6-anhydrosugars with commercially available bis(trimethylsilyl)sulfide under the action of catalytic amounts of TMSOTf smoothly afforded alpha-glycosyl thiols in very high yields and in a stereospecific way. 相似文献
77.
Jiasen Yan Dr. Xianying Han Zhaohan Dang Prof. Dr. Jiangang Li Prof. Dr. Xiangming He 《Chemphyschem》2023,24(23):e202300320
Paraffin (PA)/expanded graphite (EG) is an important composite phase change material with low cost, high heat storage, good thermal conductivity and cycling stability. Its thermal conductivity needs to be further improved for application in the thermal management system of power lithium-ion batteries. In this paper, copper plated expanded graphite (CPEG) with 3D porous structure was prepared by electroless copper plating method, which was used as thermal conductivity enhancing material to replace part of EG in PA/EG composite materials. For the optimized phase change material composed of 80 %PA-14 %EG-6 %CPEG, the copper content is very low (0.768 wt %), but its thermal conductivity can be significantly improved without loss of latent heat and thermal cycling stability. Its thermal conductivity is increased from 11 times to 16.5 times that of paraffin while compared with the copper-free composite material (80 %PA-20 %EG). The PA/EG/CPEG composite material exhibits good temperature control effect on power lithium-ion batteries. 相似文献
78.
Two-dimensional Jamus van der Waals(vdW)heterojunctions,referring to the junction containing at least one Janus material,are found to exhibit tuneable electronic structures,wide light adsorption spectra,controllable contact resistance,and sufficient redox potential due to the intrinsic polarization and unique interlayer coupling.These novel structures and properties are promising for the potential applications in eleetronics and energy conversion devices.To provide a comprehensive picture about the research progress and guide the following investigations,here we summarize their fundamental properties of different types of two-dimensional Janus vdW heterostruct ures including electronic struc-ture,interface contact and optical properties,and discuss the potential applications in electronics and energy conversion devices.The further challenges and possible research directions of the novel heterojunctions are discussed at the end of this review. 相似文献
79.
We present here a convenient synthesis of the truncated sphingoid iodide 15 from d-galactose, in which Mitsunobu reaction was utilized to retrieve successfully an unwanted intermediate, thereby increasing greatly the synthetic efficiency. Subsequent reaction of 15 with the pre-prepared α-galactosyl thiol 16 led smoothly to the desired thioglycoside 17 in good yield, from which the catabolically stable thioglycoside analogs of OCH 4 and 22 were synthesized. 相似文献
80.
L Wang X He J Li W Sun J Gao J Guo C Jiang 《Angewandte Chemie (International ed. in English)》2012,51(36):9034-9037
More than LiP service: The adsorption of red phosphorus into porous carbon provides a composite anode material for lithium-ion batteries. The amorphous nano phosphorus, in the carbon matrix, shows highly reversible lithium storage with high coulombic efficiencies and stable cycling capacity of 750?mAh per gram composite. 相似文献