Metabolite profiling of 4-methylescultin in rat using ultra-fast liquid chromatography combined with tandem mass spectrometry

Metabolite profiling of 4-methylescultin in rat using ultra-fast liquid chromatography combined with tandem mass spectrometr

Electrochemical Behavior of Aluminized Steel in Seawater Environment

　应用化学浸泡实验,电化学测试技术研究渗铝钢在海水中的电化学行为.试验表明,在海水中渗铝钢的腐蚀电位比20#钢的负,其阳极活性大于后者,在低电位下发生阳极溶解.20#钢和渗铝钢的腐蚀速率分别为5.80mg/dm2·d和3.36mg/dm2·d.渗铝钢在海水中具有优良的耐蚀性能是由于环境遮断和电偶保护的综合效果.其腐蚀产物含有氯离子,说明氯离子参与海水中的腐蚀过程,是导致腐蚀的主要原因.渗铝钢除了表层形成的Al、Fe化合物和致密、连续、具有高效防护作用Al的氧化物保护膜外,Al Fe合金层起到牺牲阳极的电化学保护作用.The electrochemical behavior of aluminized steel in seawater has been studied by immersion test and electrochemical technology. The results indicate that compared with 20# steel, the aluminized steel has lower corrosion potential and stronger anodic activity in seawater. Its anodic solution will occur at low potential. The immersion test shows that the corrosion rates of aluminized steel and 20# steel are 5.80 mg/dm~2 dand 3.36 mg/dm~2 d, respectively. Through the X-ray diffraction patternanalysis, it was found that chloride ions exit in the corrosion products of aluminized steel. It proves the participation of chloride ions in the process of corrosion, which are the main reason resulting in the corrosion. The research reveals that Aluminized steel's excellent corrosion resisting property in seawater is attributed to the combined action of the shutoff on the surface and couple protection. Besides the compact and uniform films of Al-Fe compound and the oxide of Al formed on the aluminized steel's surface, the aluminized layer as sacrificial anode can also protect the matrix.作者联系地址：大连理工大学化工学院,中国石油大连石化公司设备研究室,中国石油大连石化公司设备研究室,大连理工大学化工学院 辽宁大连116012 ,辽宁大连116032 ,辽宁大连116032 ,辽宁大连116012Author's Address: *1, WEI Jun~2, LU Si~2, ZHENG Run-fen~11. School of Chemical Engineering, Dalian University of Technology, Dalian 116012, China,2. Equipment Institute of PetroChina Company Limited Dalian Petrochemical Company,Dalian 116012,Chin

In Vitro Metabolic Study of Boc5 in human tissues and Animal Liver Microsomes

As the first nonpeptidic agonist of glucagon-like peptide 1 receptor, Boc5 can invoke sustained glycemic control and weight loss in diabetic C57BL/6J mice, and has become a promising hit compound for antidiabetic drug. Boc5 displays good efficiency via i.v. administration but loss efficiency via oral administration, thus its ADME properties should be studied. In the present study, the in vitro investigation on metabolic stability of Boc5 was first reported. Both phase I and phase II metabolic studies were carried out by using a series of tissues and microsomes from human and three experimental animals including pig, rat and C57BL/6J mice. Significant species difference in metabolism of Boc5 was presented, Boc5 can not be metabolized by human plasma, liver and intestine microsome, as well as rat and pig liver microsomes. In contrast, Boc5 can be rapid metabolized by C57BL/6J mice liver microsome (~50% conversion at 1 h), and three metabolites (M-1, M-2, and M-3) were detected by using liquid chromatography/mass spectrometry (LC/MS). M-1 was confirmed as 2-thenoic acid, and M-3 and M-2 were assigned as two metabolites after hydrolysis of one and two thenoic acids from Boc5, respectively, based on the retention times and mass spectra by comparison with standards. These results revealed that the hydrolysis of thiophene carboxylic ester bond was the major metabolic pathway of Boc5, indicating esterases invlolved in this biotransformation. Further studies have shown that carboxylesterase in C57BL/6J mice liver display the key role in rapid hydrolysis of Boc5 by using a range of inhibitors. All of these results were very useful to develop the next generation nonpeptidic agonists and to choose suitable experimental animal for whole tests

蟾蜍内酯类3-表异构体的立体特异性葡萄糖醛酸化研究

Bufadienolides, a class of natural products with a unique steroidal skeleton were separated and identified from traditional Chinese medicine Chansu, has been reported with Na+-K+-ATPase inhibitory effects and outstanding antitumor activities. In the current study, the glucuronidation of three pairs of bufadienolide epimers including Cinobufagin (CB), deacetylcinobufagin (DCB) and bufalin (BF), as well as their corresponding 3-epimers (ECB, EDCB and EBF), were investigated by using human liver microsomes (HLM). Interestingly, among these investigated compounds, only EDCB and EBF can form corresponding glucuronidated metabolite when the substrate was incubated with HLM in the presence of UDPGA, while no metabolites of CB, DCB, BF or ECB were detected under the same conditions. The EDCB mono-glucuronide and EBF mono-glucuronide were characterized by using LC-MS/MS, and these two glucuronidated metabolites were also confirmed by hydrolysis with β-glucuronidase. Further investigation on EDCB glucuronidation in human liver microsomes was carried out, due to the detection limitation for quantification of EBF glucuronide. A combination of assays with a panel of recombinant human UGT isoform(s) and chemical inhibition study were used to explore the involved isoform(s) in the EDCB glucuronidation, only UGT2B7 exhibited the catalytic activity toward EDCB glucuronidation, while the inhibitory effect of mefanamic acid (a potent inhibitor of UGT2B7) for EDCB glucuronidation in HLM was similar to its in recombinant UGT2B7. These results revealed that human UGT2B7 was the major isoform involved in the glucuronidation of EDCB. The formation of EDCB glucuronide in pooled human liver microsomes can be well fitted to a substrate inhibition model and the kinetic parameters of EDCB glucuronidation were as follows: Km=48.4 ± 12.6 µM, Ksi=342.2 ± 95.3 µM, and Vmax=1.6 ± 0.3 nmol/min/mg of protein. In summary, this study revealed a stereoselective glucuronidation pathway to bufadienolides, and our results indicated that the structure variants of these epimers including the C-16 ester and the configuration of C-3 hydroxyl may influence the glucuronidation of bufadienolides

铜基廉价催化剂的火焰合成及甲烷催化特性研究

本文基于预混滞止弱旋火焰系统,以溶于水或乙醇的廉价硝酸盐为前驱物,采用“一步”的雾化火焰方法来合成铜基催化剂纳米颗粒。采用TEM、XRD等分析了合成颗粒的形貌及物相态,进而考察了该催化剂在甲烷催化氧化反应中的催化活性。根据TEM结果,发现乙醇做溶剂时所合成的氧化铜颗粒具有颗粒直径小且结晶度较好的特点。实验结果表明,10 nm氧化铜颗粒体现出良好的甲烷催化性能,但掺杂氧化铝后,铜基催化剂对甲烷的催化性能有所下降,其原因可归结为氧化铝对氧化铜的覆盖作用导致其有效比表面积降低

铜基廉价催化剂的火焰合成及甲烷催化特性研究

本文基于预混滞止弱旋火焰系统,以溶于水或乙醇的廉价硝酸盐为前驱物,采用“一步”的雾化火焰方法来合成铜基催化剂纳米颗粒。采用TEM、XRD等分析了合成颗粒的形貌及物相态,进而考察了该催化剂在甲烷催化氧化反应中的催化活性。根据TEM结果,发现乙醇做溶剂时所合成的氧化铜颗粒具有颗粒直径小且结晶度较好的特点。实验结果表明,10 nm氧化铜颗粒体现出良好的甲烷催化性能,但掺杂氧化铝后,铜基催化剂对甲烷的催化性能有所下降,其原因可归结为氧化铝对氧化铜的覆盖作用导致其有效比表面积降低

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel