Agonist–PPARγ interactions: Molecular modeling study with docking approach

Docking simulation of 18 agonists with the ligand binding pocket (LBP) of PPARγ has been performed. The binding conformations and binding affinities of these agonists were obtained by use of the flexible docking protocol FlexX. Test compound calculations indicated that FlexX can reproduce the binding conformation of the crystal structure (root mean square deviation = 1.43 Å); moreover, the predicted binding affinities correlate well with the activities of these agonists. The interaction model and pharmacophore of PPARγ agonists were derived and the difference in biologic activities of these agonists can be well explained. The PPARγ agonists must have both polar head and the hydrophobic tail, which form hydrogen bonds and hydrophobic contacts with hydrophilic and hydrophobic regions of the LBP of PPARγ, respectively. In addition, a suitable linker is also necessary. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 93: 405–410, 2003     

Hydrothermal Synthesis of Two New Transition Metal Coordination Polymers with Mixed Ligands

Hydrothermal reactions of 1, 2, 4‐benzenetricarboxylic acid, 1, 10‐phenanthroline and transition metal cations including Zn^II or Co^II, in basified aqueous solution gave rise to two complexes, [Zn₃(btrc)₂(1, 10‐phen)₂(H₂O)₂]_n ( 1 ), and [Co₃(btrc)₂(1, 10‐phen)₂(H₂O)₂]_n ( 2 ) (btrc = 1, 2, 4‐benzenetricarboxylate, and 1, 10‐phen = 1, 10‐phenanthroline). 1 2 crystalize isotypically in the triclinic space group P1¯. The btrc ligand acts as multi‐dentate bridging ligand in both compound 1 and 2 to link up transition metal atoms into lamella networks, which are further attached into three‐dimensional frameworks through complex hydrogen bonding and π‐π interactions. The photoluminescence spectrum for compound 1 has also been studied. The corresponding reaction with Cu²⁺ follows another pathway.     

The Efficient Synthesis of the Optically Active β‐Hydroxyl‐γ‐Butyrolactone Derivatives

The optically active β‐hydroxyl‐γ‐butyrolactones were synthesized from nonchiral starting material by employing reductive cleavage reaction, sharpless asymmetric epoxidation and dihydroxylation, and Lewis acid‐catalysed cyclization as key steps. This strategy can be used to prepare many chiral β‐hydroxyl‐γ‐butyrolactone analogues.     

新型离子液体基质用于MALDI-MS高效离子化寡糖/糖肽

本研究发展了四种基于三羟基苯乙酮(THAP)的新型离子液体基质, 即2',3',4'-THAP/二甲基苯胺(DMA)、2',4',6'-THAP/DMA、2',3',4'-THAP/吡啶(Py)及2',4',6'-THAP/Py, 用于提高寡糖/糖肽在MALDI-TOF MS中的离子化效率. 与传统的固体基质2,5-二羟基苯甲酸(DHB)和2',4',6'-三羟基苯乙酮(2',4',6'-THAP)相比, 新型离子液体体系分析不同类型的寡糖链, 均可获得更高的检测灵敏度. 可使葡聚糖(dextran 1000)和环状寡聚糖β-环糊精在MALDI质谱中的信噪比提高10倍以上, RNase B的复杂寡糖链也实现了高灵敏度的检测. 在糖肽分析中, 2',3',4'-THAP/DMA离子液体高灵敏度地检测到辣根过氧化酶的7条糖肽, 而2',3',4'-THAP作为基质时却无法检测到任何信号.     

负载型双金属铁钯纳米催化降解微囊藻毒素-LR

探讨膨润土负载双金属铁钯(B-Fe/Pd)纳米材料催化降解微囊藻毒素-LR(MC-LR)的效果和机理.结果表明,在5mgL-1的MC-LR溶液中加入0.1g的纳米B-Fe/Pd,初始pH为6.86,振荡速度为250rmin-1,温度为298K的条件下,经过180min后对MC-LR的降解效率达96.86%.降解溶液的UV-vis和HPLC结果表明,MC-LR在238nm的特征峰消失.通过SEM-EDS、XRD、FTIR和XPS技术对B-Fe/Pd降解前后的样品进行表征,结果显示,降解后纳米B-Fe/Pd中的Fe形成了Fe的氧化物与氢氧化物.降解过程的动力学拟合结果显示,B-Fe/Pd降解MC-LR符合伪一级动力学,活化能为12.77kJmol-1.根据降解、表征和动力学结果分析其反应机理,推断是MC-LR首先吸附在B-Fe/Pd颗粒表面,接着纳米铁与水反应产生的氢气在Pd的催化作用下产生大量的氢自由基,并与MC-LR发生链式还原反应,使得MC-LR中最具毒性的共轭双键断开而降解.     

Treatment of mature landfill leachate by a continuous modular internal micro-electrolysis Fenton reactor

A modular internal micro-electrolysis Fenton reactor (MIME-Fenton) was specifically designed in order to facilitate the performance of internal micro-electrolysis (IME) technology in the treatment of mature landfill leachate. Excellent COD removal efficiency of 90.9 % by the new reactor of mature landfill leachate was observed in bench-scale treatment, which is 193–399, 415–551, and 226–457 % higher than that of conventional treatments of electrolysis, coagulation–sedimentation, and Fenton, respectively. The innovative concept behind the excellent performance is the novel two-step treatment, similar to the anaerobic–aerobic activated sludge method. It is based on a combination effect of reductive IME and oxidative IME with aeration processes and the integration of electro-aggregation and electro-coagulation. Initial pH and air flow rate were optimized, and the effect of auxiliary in situ regeneration of ferrous iron and generation of H₂O₂ was further investigated. The reactor was also particularly efficient in removal of color and HA, and in improvement of the BOD₅/COD ratio. All these results show that the MIME-Fenton reactor, a new approach of IME, is promising for mature landfill leachate treatment because it is efficient and easy to operate.     

聚乙烯基吡咯烷酮-多壁碳纳米管复合修饰玻碳电极用于差分脉冲伏安法测定抗坏血酸

采用超声辐射法制备了聚乙烯基吡咯烷酮（PVP）-多壁碳纳米管（MWCNT’s）复合材料（PVP-MWCNT’s）,将该复合材料分散在N,N-二甲基甲酰胺（DMF）中并滴涂在玻碳电极表面,制备了聚乙烯基吡咯烷酮-多壁碳纳米管复合修饰玻碳电极（PVP-MWCNT’s/GCE）。研究发现:抗坏血酸在修饰电极上出现一对可逆的氧化还原峰,提出了用差分脉冲伏安法测定抗坏血酸的方法。还原峰电流与抗坏血酸的浓度在1.0×10^-7～1.0×10^-3 mol·L^-1范围内呈线性关系。     

Effect of Precursor Drying Process on the Properties of LiFePO4/C Composite with Low Carbon Content

<正>Properties of two LiFePO_4/C composites with low carbon content synthesized from precursors dried by spray drying and blast drying are investigated by scanning electron microscopy, X-ray diffraction, Raman spectroscopy and electrochemical measurements. The two samples have a different morphology and particle size, while the structure of LiFePO_4 is unaffected. The LiFePO_4/C composite prepared from the precursor dried by blast drying has a much lower surface resistance and a much better rate capability because the deposited carbon is more graphite-like and more conductive. The cycling performance is also much better for the LiFePO_4/C composite prepared from the precursor dried by blast drying because only a slight impedance growth is involved upon cycling. These results suggest that the precursor drying process has a significant impact on the properties of LiFePO_4/C composite, and its effect is highly dependent on the carbon content.     

铈对三角帆蚌钙代谢影响的研究

研究了不同浓度稀土Ce3+(0,0.5,1.0,2.5 mg·L-1)处理30,60 d时对2龄植片三角帆蚌钙代谢和珍珠质沉积的影响。结果表明:Ce3+对三角帆蚌珍珠质沉积量、外套膜和鳃组织中组织钙含量、钙调蛋白基因mRNA的表达量、腺苷三磷酸酶(ATPase)活性、碱性磷酸酶(ALP)活性的影响总体上均表现出明显的"低促高抑"的剂量效应和高浓度下"先促后抑"的时间效应。推测稀土Ce3+对钙调蛋白基因mRNA表达水平及关键酶活性的调节可能是其影响三角帆蚌钙代谢和珍珠质沉积的途径之一。     

Simultaneous determination of seven prohibited substances in cosmetic products by liquid chromatography-tandem mass spectrometry

In this paper,we developed and validated a simple,sensitive,and selective high-performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS) method to identify and measure the following prohibited substances that may be found in cosmetic products:minoxidil,hydrocortisone, spironolactone,estrone,canrenone,triamcinolone acetonide and progesterone.Chromatographic separation was performed on a Waters Symmetry C18(100 mm×2.1 mm,3.5μm particle size) with a gradient elution system composed of 0.2%(v/v) formic acid aqueous solution and methanol containing 0.2%(v/v) formic acid at a flow rate of 0.3 mL/min.The substances were detected using a triple quadrupole mass spectrometer in the multiple reaction monitoring mode with an electrospray ionization source.All of the calibration curves showed good linearity(r > 0.999) within the tested concentration ranges.The limit of detection was <25 pg.The relative standard deviations for intraday precision for each of the prohibited substances were <3.5%at two concentration levels(2μg/g,10μg/g). The relative recovery rate for each of the prohibited substances ranged from 91.8%to 111%at three concentration levels(0.1μg/g,2μg/g,10μg/g),including the limit of quantification.In conclusion,we have developed and validated a method that can identify seven prohibited substances in cosmetic products.