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排序方式: 共有171条查询结果,搜索用时 15 毫秒
1.
Spectroscopic characterization of effective components anthraquinones in Chinese medicinal herbs binding with serum albumins 总被引:2,自引:0,他引:2
Bi S Song D Kan Y Xu D Tian Y Zhou X Zhang H 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,62(1-3):203-212
The interactions of serum albumins such as human serum albumin (HSA) and bovine serum albumin (BSA) with emodin, rhein, aloe-emodin and aloin were assessed employing fluorescence quenching and absorption spectroscopic techniques. The results obtained revealed that there are relatively strong binding affinity for the four anthraquinones with HSA and BSA and the binding constants for the interactions of anthraquinones with HSA or BSA at 20 degrees C were obtained. Anthraquinone-albumin interactions were studied at different temperatures and in the presence of some metal ions. And the competition binding of anthraquinones with serum albumins was also discussed. The Stern-Volmer curves suggested that the quenching occurring in the reactions was the static quenching process. The binding distances and transfer efficiencies for each binding reactions were calculated according to the F?ster theory of non-radiation energy transfer. Using thermodynamic equations, the main action forces of these reactions were also obtained. The reasons of the different binding affinities for different anthraquinone-albumin reactions were probed from the point of view of molecular structures. 相似文献
2.
Surface plasmon resonance (SPR) has been successfully applied for the simple, rapid, and label-free assay of various biomolecules. This assay evaluates a novel wavelength modulation SPR biosensor for the detection of tetanus toxin. The wavelength modulation SPR biosensor is designed based on fixing the incident angle of light and measuring the reflected intensities in the resonance wavelength range spanning 400-800 nm simultaneously. Tetanus toxin (TeNT), one of the most potent toxins known, is synthesized as a 150 kDa single polypeptide chain. The SPR biosensor has been shown to be capable of directly detecting concentration of tetanus toxin as low as 0.028 Lf ml−1. Under selected experimental conditions, the SPR biosensor has a good reproducibility, sensitivity and reversibility. The results illustrate how wavelength modulation SPR biosensor can be used to detect biomolecular interactions. 相似文献
3.
微波等离子体光谱法测定碲的研究 总被引:2,自引:0,他引:2
微波等离子体原子发射光谱法(MIPAES)测定碲,前人已作过一些工作。本文利用我们建立的微量进样系统与MIPAES联用,对碲的测定进行了研究。实验中发现,加入适量的SnCl_2可降低检出限约一个数量级,Te_(214.3nm)的检出限为5 ng/mL,同时还研究了碱金属卤化物对碲的测定的影响。 相似文献
4.
In complex network environments, there always exist heterogeneous devices with different computational powers. In this work, we propose a novel scalable random linear network coding (RLNC) framework based on embedded fields, so as to endow heterogeneous receivers with different decoding capabilities. In this framework, the source linearly combines the original packets over embedded fields based on a precoding matrix and then encodes the precoded packets over GF(2) before transmission to the network. After justifying the arithmetic compatibility over different finite fields in the encoding process, we derive a sufficient and necessary condition for decodability over different fields. Moreover, we theoretically study the construction of an optimal precoding matrix in terms of decodability. The numerical analysis in classical wireless broadcast networks illustrates that the proposed scalable RLNC not only guarantees a better decoding compatibility over different fields compared with classical RLNC over a single field, but also outperforms Fulcrum RLNC in terms of a better decoding performance over GF(2). Moreover, we take the sparsity of the received binary coding vector into consideration, and demonstrate that for a large enough batch size, this sparsity does not affect the completion delay performance much in a wireless broadcast network. 相似文献
5.
Peixu Zhang Yongri Jin Jiafeng Chen Hua Yao Hanqi Zhang Aimin Yu Xuwen Li 《Chromatographia》2013,76(15-16):967-974
In this work, a novel method based on ultrasonic-assisted nebulization extraction coupled with solid phase extraction (UANE-SPE) and determined by high performance liquid chromatography was developed for the determination of triterpenoids in root of Euphorbia pekinensis Rupr. The experimental conditions for the UANE-SPE, such as type of extraction solvent, sample amount, type and amount of sorbent, extraction time and volume of the elution solvent, were examined and optimized. The method was successfully applied to determine euphol and tirucallol in the dried root of E. pekinensis Rupr. The recoveries of the analytes were in the range of 89.1–102.0 %. The limits of detection were 12 μg g?1 for tirucallol and 10 μg g?1 for euphol. The extraction yields obtained by the proposed method are higher than those obtained by the conventional extraction methods, such as reflux and ultrasonic-assisted extraction. Compared with the traditional methods, the proposed method can reduce the consumption of the labor, shorten the sample preparation time and increase the efficiencies in the extraction of active constituents from plant materials. 相似文献
6.
7.
Capillary electrophoresis using 1-butyl-3-methylimidazolium tetrafluoroborate as background electrolyte for the separation and determination of 11 amino acids was studied. Several parameters, such as ionic liquid concentration, pH of background electrolyte and applied voltage, were optimized. Amino acids were derived with Sanger’s reagent (2,4-dinitrofluorobenzene) and the detection was performed by an ultraviolet absorption detector at 360 nm. Under selected conditions, 11 amino acids were completely separated within 16 min. The RSD values of integrated areas and migration times are <3.03 and <1.64%, respectively. The electroosmotic flow can be influenced by imidazolium cation, and the association between the imidazolium cation and the derived amino acids plays an important role in the separation mechanism. This method not only provides an approach for the separation and determination of amino acids, but is also an extension of the ionic liquid application to capillary electrophoresis. 相似文献
8.
9.
Lan Luo Ziyi Zhang Yanhua Chen Lixia Zhang Xiangfeng Bu Hanqi Zhang 《International journal of environmental analytical chemistry》2017,97(12):1178-1191
A simple and sensitive surface-enhanced Raman spectroscopy (SERS) method for the detection of safranine T (ST) and Hg2+ using silver nanoparticles (AgNPs) as substrate was developed. ST can absorb on the surface of AgNPs through electrostatic interaction, the electromagnetic effect combined with chemical adsorption effect give a notable Raman enhancement for ST. The presence of Hg2+ well decreased the absorbed ST molecules on AgNPs, leading to a significant decrease of SERS signals thus enabling to detect Hg2+. The determination conditions for SERS, including the amount of AgNPs, the concentration of NaCl, the concentration of HCl, the concentration of ST and the reaction time, were optimised. Under the optimised experimental conditions, good linear responses were obtained for ST and Hg2+ in the concentration ranges of 0.01–4.0 μmol L?1 (3.5–1403.4 ng mL?1) and 0.01–2.0 μmol L?1 (2.0–401.2 ng mL?1), the limit of detection were 3.0 nmol L?1 (1.1 ng mL?1) and 2.0 nmol L?1 (0.4 ng mL?1), respectively. The present method was subsequently applied to the determination of ST in tomato sauces and Hg2+ in environmental waters, the recoveries of ST and Hg2+ in spiked samples are 95.5–107.8% and 91.4–110.8 %, respectively. 相似文献
10.
Xiaolei Shi Xuwen Li Yantao Sun Wei Wei Ruijie Yang Hanqi Zhang Yongri Jin 《Journal of solution chemistry》2010,39(4):482-494
The interaction between taxifolin and bovine serum albumin (BSA), and the effects of some common ions on their interaction,
were investigated by fluorescence and UV-visible absorption spectroscopy. The results indicate that taxifolin has a strong
ability to quench the intrinsic fluorescence of BSA through a static quenching process. According to values of the thermodynamic
parameters, the hydrophobic force plays a major role in the interaction. Based on Főster’s non-radiation theory, the energy
transfer distances between BSA and taxifolin in the absence and presence of some common ions were obtained. The experimental
results indicate that the transfer distances are almost unaffected by these ions. The conformation of BSA undergoes significant
change from the formation of a taxifolin–BSA complex, which was studied by synchronous and three-dimensional fluorescence
spectroscopy. 相似文献