计算肽学

肽作为重要的生理活性物质一直受到相关领域的广泛关注。近年来,由于肽在细胞信号转导中所扮演的中心角色以及作为生物药物靶向蛋白质相互作用网络等特殊性质的发现,再次唤起了人们对肽的浓厚兴趣。与之相伴的是,肽的理论和计算研究工作快速增长,并取得了长足进展。本文以“计算肽学”为主题系统概括了该领域的研究范畴和研究特点,并分别从肽的数据库构建、功能活性预测、分子对接、动力学模拟、结构数据分析、分子设计修饰以及系统生物学行为等几方面分类介绍了计算肽学的主要研究方向和当前发展状况。重点在于探讨采用计算化学和生物信息学方法剖析肽与蛋白质识别和相互作用的分子机制和理化基础,进而为肽类药物设计提供理论指导。此外,本文还提出了计算肽学在肽类纳米材料及生物表面活性剂等领域的潜在应用前景。     

木质素模型化合物在二氧化钛纳米管上光电氧化的动力学研究(英文)

本文用电化学方法制备了二氧化钛纳米管,并用扫描电子显微镜和X衍射对其形貌及组成进行了表征.进一步研究了木质素的两个模型化合物1-(3,4-dimethoxyphenoxy)-2-(2-methoxyphenoxy)-1,3-propanediol(DMP)和3-hydroxy-1-(3,4-dimethoxyphenoxy)-2-(2-methoxyphenoxy)-1,3-propanone(HDM)在二氧化钛纳米管上的光电氧化.在DMP的光电氧化过程中,一个新的紫外吸收峰出现在波长304 nm处.虽然中间体的形成速率随着浓度的增加而增加,却随着温度的增加而减少.尽管HDM和DMP在结构上有很小的差别,在氧化过程中DMP却呈现出很小的吸光度变化,表明HDM不易被光电氧化.量子化学计算结果也表明,DMP更容易被氧化,这个结果与光电氧化的结果相吻合.     

A new strategy for synthesizing the steroids with side chains from steroidal sapogenins: synthesis of the aglycone of OSW-1 by using the intact skeleton of diosgenin

The protected aglycone of saponin OSW-1, a new antitumor natural product, was synthesized in 13 linear steps in 9.5% overall yield by utilizing the intact skeleton of diosgenin. This strategy demonstrated a higher efficiency than the routine synthesis of steroids with side chains.     

The Synthesis of Gracillin and Dioscin：TWO Typical Representatives of Spirostanol Glycosides

Two spirostanol saponins(gracillin and dioscin)which have the typical sugar moieties were synthesized facilely by a general approach.     

A Facile Synthesis of Squamosamide Cyclic Analogs

A series of novel cyclic derivatives have been synthesized by utilizing a nickel powder mediated radical cyclization as the key step. The structures of the new compounds were confirmed by ^lH-NMR and MS.     

A Promising MoO_x-based Catalyst for n-Heptane Isomerization

The increasing demand for higher-octane gasoline and the regulations limiting the amount of aromatics in the fuel motivate the interest in catalytic isomerization of n-alkanes. In the last ten years, transition metal oxides or oxycarbides based on molybdenum or tungstate have attracted much attention due to their high activity and isomerization selectivity compared to the conventional bifunctional supported platinum catalyst and high resistance to sulphur and nitrogen catalyst poisons1-5. Ma…     

沉淀转化法制备多孔片状纳米LaF3

采用实验中所合成的LaPO4纳米棒为前驱体,通过沉淀的转化作用,大面积地制备了单分散的片状纳米LaF3。采用扫描电镜(SEM)、透射电镜(TEM)、X射线衍射仪(XRD)、BET(Brunauer-Emmett-Teller)测试对片状纳米LaF3的形貌、结构、相组成及表面性质进行了分析。片状纳米LaF3底边长约为40 nm,片的厚度约为35 nm,大小均一,具有多孔结构。通过改变反应溶剂,可以控制LaF3粒子的成核、生长和团聚,从而有效地调控多孔片状纳米LaF3的颗粒尺寸和分散性。对多孔片状纳米LaF3的生长机制进行了研究,结果表明LaPO4和LaF3的溶度积常数差导致了片状纳米LaF3的生成;体系中自身存在的Ostwald ripening作用使片状纳米LaF3出现了多孔结构。     

Detect early stage lung cancer by a LAMP microfluidic chip system with a real-time fluorescent filter processor

This work presents a promising clinical molecular diagnostics for early stage lung cancer. This novel diagnostic method utilized the loop-mediated isothermal amplification (LAMP), microfluidic chips and a confocal optical detector with a non-linear fluorescent filter processor. An isothermal amplification based microfluidic chip for the early diagnostics of lung cancer was developed and a confocal optical detector was improved by a novel real-time fluorescent filter to sensitively monitor the DNA amplification procedure with high signal to noise ratio and fluorescence collecting ability. Experiment showed that a rapid diagnostic of lung cancer by detecting the existence of the CEA mRNA could be performed in only 5 μL of reaction assay in less than 45 min. While the traditional in-tube RT-PCR set consumed more than 25 μL of the assay and took more than 90 min.     

Gliding Arc Discharge for Decolorization and Biodegradability of Azo Dyes and Printing and Dyeing Wastewater

Gliding arc discharge process was used for the pretreatment of four azo dye solutions, which are classified to acidic, reactive and chemical indicator, as well as printing and dyeing wastewater with the objective of improving their overall biodegradability. The percentage color removal of all samples were found to be over 92% after 40?min treatment, and the color disappearance of four azo dyes followed the first-order kinetics completely. The biochemical oxygen demand (BOD₅)/chemical oxygen demand (COD) ratio increased from 0.02 to 0.46 for acid orange II (AO7), 0.173 to 0.55 for methyl orange, 0.019 to 0.4 for direct fast black, 0 to 0.65 for reactive red K-2BP. The decolorization of printing and dyeing wastewater achieved 97.5% and the COD removal efficiency was 76.6%. The BOD₅/COD ratio increased to 0.55 after 20?min treatment. The experimental results indicates it is possible to combine gliding arc discharge with conventional biological treatment for the remedy of wastewater containing generally non-biodegradable dye.     

Photocatalytic degradation of methylene blue and phenol on Fe-doped sulfated titania

Fe-doped sulfated titania (FST) photocatalysts with high photocatalytic activity were prepared from industrial titanyl sulfate solution and characterized using X-ray diffraction (XRD), thermogravimetry analysis?Cdifferential scanning calorimeter (TGA-DSC), Fourier transform infrared spectroscopy (FT-IR), and nitrogen adsorption?Cdesorption techniques. The photocatalytic activity of the FST photocatalyst was evaluated using the photodegradation of methylene blue (MB) and the photooxidation of phenol in aqueous solutions in the presence of UV irradiation, respectively. The effect of various parameters, such as calcining temperature, calcination time, initial concentration of substrate, amount of catalyst and pH value on the photocatalytic activity of FST photocatalyst was investigated. Among the parameters studied, calcining temperature, initial concentration of substrate, and amount of catalyst have a very similar effect on the activity of FST photocatalyst for both the photodegradation of MB and the photooxidation of phenol, while the others have distinct differences. The optimal calcination conditions were 500?°C, 1.5?h and 650?°C, 2.5?h; the optimal catalyst concentration were 1.0 and 1.2?g?L^?1; the optimal pH values were 8 and 4 for the photodegradation of MB and the photooxidation of phenol, respectively. In addition, the mechanism for the high photocatalytic efficiency of FST photocatalyst has also been put forward.