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51.
Yao D Vlessidis AG Gou Y Zhou X Zhou Y Evmiridis NP 《Analytical and bioanalytical chemistry》2004,379(1):171-177
A novel flow-injection chemiluminescence-based method has been developed for determination of superoxide dismutase (SOD) activity. An in-vitro superoxide anion generation xanthine/xanthine oxidase stable source was established on line with FIA/CL-detection apparatus, for measuring SOD activity. This method can detect SOD in the linear range of 0.002–2.00 U mL–1 with a detection limit of 0.001 U mL–1. Another method for detection of superoxide anion is based on the luminol–FeCl3 chemiluminescence (CL) reaction. This method was used to evaluate superoxide release and SOD activity in rats treated with the traditional Chinese herb Pulsatilla chinensis, which resulted in high clearance of hepatitis B virus (HBV) after treatment of a hepatitis B patient. Interestingly, we found that treatment with Pulsatilla chinensis can specifically increase superoxide release by liver tissues and, at the same time, slightly increase extracellular SOD (ECSOD) activity in plasma; in particular it can markedly increase MnSOD activity in mitochondria in liver tissue. This work revealed a possible mechanism whereby Pulsatilla chinensis prevents possible infection (for example HBV) by specifically increasing superoxide release in the liver and increasing MnSOD activity to minimize superoxide-mediated toxicity. 相似文献
52.
Diode laser extended cavity for broad-range fast ramping 总被引:1,自引:0,他引:1
A novel design for an extended-cavity diode laser is presented. The cavity contains an electro-optic prism for synchronous tuning of the cavity length and the grating's incident angle. A simple analysis of the cavity is presented. Experimental results are reported that show mode-hop-free tuning over more than 10 GHz with high linearity and reproducibility. To the authors' knowledge, this is the first demonstration of mode-hop-free tuning of an extended cavity over several free spectral intervals with an electro-optic crystal. 相似文献
53.
采用化学浸提-电感耦合等离子体发射光谱法(ICP-OES)测定粉条中溶出铝的化学形态及其含量.实验结果显示,粉条溶出铝中,Al3+为135 μg/g,Al(OH)2+和Al(OH)2-未检出,胶态Al(OH)3o为143 μg/g,有机铝为460 μg/g.各化学形态铝含量的回收率在88.3%~105%范围,精密度(RSD)为1.14%,方法检出限为0.74 mg/kg.该方法准确度高,精密度好,检出限低,线性关系好,是一种简便实用的食品、药物中活性铝化学形态的检测方法. 相似文献
54.
Yang An Bo-Sheng Zhang Ya-Nan Ding Zhe Zhang Xue-Ya Gou Xue-Song Li Xiaolei Wang Yuke Li Yong-Min Liang 《Chemical science》2021,12(39):13144
This report describes palladium-catalyzed C–H glycosylation and retro Diels–Alder tandem reaction via structurally modified norbornadienes (smNBDs). smNBDs were proposed to regulate the reactivity of the aryl-norbornadiene-palladacycle (ANP), including its high chemoselectivity and regioselectivity, which were the key to constructing C2 and C3 unsubstituted C4-glycosidic indoles. The scope of this substrate is extensive; the halogenated six-membered and five-membered glycosides were applied to the reaction smoothly, and N-alkyl (primary, secondary and tertiary) C4-glycosidic indoles can also be obtained by this method. In terms of mechanism, the key ANP intermediates characterized by X-ray single-crystal diffraction and further controlled experiments proved that the migration-insertion of smNBDs with phenylpalladium intermediate endows them with high chemo- and regioselectivity. Finally, density functional theory (DFT) calculation further verified the rationality of the mechanism.This report describes palladium-catalyzed C–H glycosylation and retro Diels–Alder tandem reaction via structurally modified norbornadienes (smNBDs). 相似文献
55.
Xingxing Gou Xiaohua Pu Zongxiao Li 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2017,91(11):2110-2116
In this paper, we selected quercetin and aromatic amino acids (tryptophan, tyrosine, phenylalanine) as the research objects to investigate the change rules in the reaction process. The thermodynamic functions (Ka, ΔG, and ΔS) of the interactions between quercetin and aromatic amino acids (tryptophan, tyrosine, phenylalanine) were measured by isothermal titration calorimetry. The values of binding constant (Ka) reached maximum at 25°C; the entropies and Gibbs free energies were both negative at different temperatures. The kinetic parameters of quercetin and amino acids in the interaction process was determined by microcalorimetry. The results inferred that the driving force of the reaction was hydrogen bond or van der Waals force. 相似文献
56.
本文提出一种利用材料Hugoniot数据研究高压下离子晶体中微观离子状态及其离子间排斥作用势的新方法。对氢化锂晶体进行研究时,我们得到Li~+和H~-离子之间排斥作用势函数,结果表明文献〔1〕中提出的离子压缩效应具有客观性。 相似文献
57.
58.
JianGouHUANG ManCaiXU HaiTaoLI ZuoQingSHI 《中国化学快报》2003,14(9):914-916
Two polymeric adsorbents, poly(methyl p-vinylbenzvl ether) and oolv(ohenvl p-vinylbenzyl ether), were synthesized from chloromethylated polystyrene, Their adsorptionproperty for phenol in hexane solution was investigated. The results showed that the twoadsorbents adsorb phenol from hexane solution through hydrogen-bonding and π-π stacking interaction. 相似文献
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