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Metabolic profiles of dioscin in rats revealed by ultra‐performance liquid chromatography quadrupole time‐of‐flight mass spectrometry 下载免费PDF全文
He Zhu Jin‐Di Xu Qian Mao Hong Shen Ming Kong Jian‐Ping Chen Song‐Lin Li 《Biomedical chromatography : BMC》2015,29(9):1415-1421
Dioscin (DIS), one of the most abundant bioactive steroidal saponins in Dioscorea sp., is used as a complementary medicine to treat coronary disease and angina pectoris in China. Although the pharmacological activities and pharmacokinetics of DIS have been well demonstrated, information regarding the final metabolic fates is very limited. This study investigated the in vivo metabolic profiles of DIS after oral administration by ultra‐performance liquid chromatography quadrupole time‐of‐flight mass spectrometry method. The structures of the metabolites were identified and tentatively characterized by means of comparing the molecular mass, retention time and fragmentation pattern of the analytes with those of the parent compound. A total of eight metabolites, including seven phase I and one phase II metabolites, were detected and tentatively identified for the first time. Oxidation, deglycosylation and glucuronidation were found to be the major metabolic processes of the compound in rats. In addition, a possible metabolic pathway on the biotransformation of DIS in vivo was proposed. This study provides valuable and new information on the metabolism of DIS, which will be helpful for further understanding its mechanism of action. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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We prove Schauder estimates for solutions to both divergence and non-divergence type higher-order parabolic systems in the whole space and a half space. We also provide an existence result for the divergence type systems in a cylindrical domain. All coefficients are assumed to be only measurable in the time variable and Hölder continuous in the spatial variables. 相似文献
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High‐Nuclear Organometallic Copper(I)–Alkynide Clusters: Thermochromic Near‐Infrared Luminescence and Solution Stability 下载免费PDF全文
Hong‐Yan Zhuo Dr. Hai‐Feng Su Zhao‐Zhen Cao Wei Liu Prof. Shu‐Ao Wang Lei Feng Dr. Gui‐Lin Zhuang Dr. Shui‐Chao Lin Prof. Mohamedally Kurmoo Prof. Chen‐Ho Tung Dr. Di Sun Prof. Lan‐Sun Zheng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(49):17619-17626
Cu(CF3COO)2 reacts with tert‐butylacetylene (tBuC≡CH) in methanol in the presence of metallic copper powder to give two air‐stable clusters, [CuI15(tBuC≡C)10(CF3COO)5]?tBuC≡CH ( 1 ) and [CuI16(tBuC≡C)12(CF3COO)4(CH3OH)2] ( 2 ). The assembly process involves in situ comproportionation reaction between Cu2+ and Cu0 and the formation of two different clusters is controlled by reactants concentration. The clusters consist of Cu15 and Cu16 cores co‐stabilized by strong by σ‐ and π‐bonded tert‐butylethynide and CF3COO? (together with methanol molecule in 2 ). Their stabilities in solution were confirmed using electrospray ionization mass spectrometry in which the cluster core remains intact for 1 in chloroform and acetone, and for 2 in acetonitrile. Strong thermochromic luminescence in the near infrared (NIR) region was observed in the solid‐state. Of particular interest, the emission maximum of 1 is red‐shifted from 710 nm at 298 K to 793 nm at 93 K, along with a 17‐fold fluorescence enhancement. In contrast, 2 exhibits red shift from 298 to 123 K followed by blue shift from 123 to 93 K. The emission wavelength was correlated with the structural parameters using variable‐temperature X‐ray single‐crystal analyses. The rich cuprophilic interaction plays a significant role in the formation of 3LMCT (tBuC≡C→Cux) excited state mixed with cluster‐centered (3CC) characters, which can be considerably influenced by temperature, leading to thermochromic luminescence. The present work provides 1) a new synthetic protocol for the high‐nuclear CuI–alkynyl clusters; 2) a comprehensive insight into the mechanism of thermochromic luminescence; 3) unusual emissive materials with the characters of NIR and thermochromic luminescence simultaneously. 相似文献
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Enhanced Peroxidase‐Like Properties of Graphene–Hemin‐Composite Decorated with Au Nanoflowers as Electrochemical Aptamer Biosensor for the Detection of K562 Leukemia Cancer Cells 下载免费PDF全文
Dr. Jing Liu Meirong Cui Dr. Li Niu Dr. Hong Zhou Prof. Dr. Shusheng Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(50):18001-18008
Graphene composites with hemin and gold nanoparticles show a better performance for hydrogen peroxide decomposition compared to that of the three components alone or duplex/hybrid complexes. Our previous studies showed that the morphology of the Au nanoparticles may greatly influence the catalytic activity of graphene‐family peroxidase mimics. Recently, we found that Au nanoflowers could grow in situ and form on the surface of hemin/RGO (reduced graphene oxide). The prickly morphology of this Au nanoflower brought a higher catalytic ability with enhanced kinetic parameters than traditional Au nanoparticles that showed a smooth surface. Therefore, based on this discovery, a smart electrochemical aptamer biosensor for K562 leukemia cancer cells was further presented with good performance in selectivity and sensitivity attributed to the excellent mimetic peroxidase catalytic activity of this newly synthesized Au nanoflower decorated graphene–hemin composite (H‐RGO‐Au NFs). 相似文献
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Chul‐Soon Lee Zhengfei Dai Seong‐Yong Jeong Chang‐Hoon Kwak Bo‐Young Kim Do Hong Kim Prof. Ho Won Jang Joon‐Shik Park Prof. Jong‐Heun Lee 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(21):7102-7107
Monolayers of periodic porous Co3O4 inverse opal (IO) thin films for gas‐sensor applications were prepared by transferring cobalt‐solution‐dipped polystyrene (PS) monolayers onto sensor substrates and subsequent removal of the PS template by heat treatment. Monolayer Co3O4 IO thin films having periodic pores (d≈500 nm) showed a high response of 112.9 to 5 ppm C2H5OH at 200 °C with low cross‐responses to other interfering gases. Moreover, the selective detection of xylene and methyl benzenes (xylene+toluene) could be achieved simply by tuning the sensor temperature to 250 and 275 °C, respectively, so that multiple gases can be detected with a single chemiresistor. Unprecedentedly high ethanol response and temperature‐modulated control of selectivity with respect to ethanol, xylene, and methyl benzenes were attributed to the highly chemiresistive IO nanoarchitecture and to the tuned catalytic promotion of different gas‐sensing reactions, respectively. These well‐ordered porous nanostructures could have potential in the field of high‐performance gas sensors based on p‐type oxide semiconductors. 相似文献
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Anh N. Hong Diana Luong Mohammed Alghamdi Wei-Cheng Liao Weiyi Zhang Emily Kusumoputro Yichong Chen Prof. P. Alex Greaney Prof. Yongtao Cui Prof. Jing Shi Prof. Xianhui Bu Prof. Boniface P. T. Fokwa Prof. Pingyun Feng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(52):e202201576
Two new rod-packing metal–organic frameworks (RPMOF) are constructed by regulating the in situ formation of the capping agent. In CPM-s7, carboxylate linkers extend 1D manganese-oxide chains in four additional directions, forming 3D RPMOF. The substitution of Mn2+ with a stronger Lewis acidic Co2+, leads to an acceleration of the hydrolysis-prone sulfonate linker, resulting in presence of sulfate ions to reduce two out of the four carboxylate-extending directions, and thus forming a new 2D rod-packing CPM-s8. Density functional theory calculations and magnetization measurements reveal ferrimagnetic ordering of CPM-s8, signifying the potential of exploring 2D RPMOF for effective low-dimensional magnetic materials. 相似文献
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