金属载体催化剂的涂层研究

在高温氧化处理不同时间的金属载体箔片上涂覆MgAl2O4/Al2O3过渡涂层,利用TG-DSC,XRD,SEM,BET和超声振动等分析测试技术,对载体和涂层的微观结构与表面特性进行研究.结果表明,在950 ℃下高温氧化5 h,箔片表面生成板状Al2O3晶须,有利于增强涂层与箔片的附着力.在载体表面涂覆一层MgAl2O4/Al2O3过渡涂层,有助于提高活性组分与金属载体的结合力,可以获得高结合强度的涂层结构,促使活性元素高度分散.     

由纳米晶前驱体组装有序介孔silicalite-1分子筛

采用两步法将不同尺寸的silicalite-1分子筛纳米晶种通过自组装合成了一系列有序介孔silicalite-1分子筛。首先将强碱性的silicalite-1前驱体分别加热不同时间得到纳米晶种,然后在类似合成SBA-15的强酸性条件下组装成有序的介孔材料。合成条件的剧烈变化阻止了分子筛晶种的继续长大,并在三嵌段共聚物模板的诱导下组装成有序介孔材料。这种“自下而上”的方法制备有序介孔分子筛同时包含微孔和介孔。氮气吸脱附结果表明所制备的介孔分子筛材料均表现了很大的比表面积(730 m2/g以上)。     

A Halogen‐Bonded Dimeric Resorcinarene Capsule

Iodine (I₂) acts as a bifunctional halogen‐bond donor connecting two macrocyclic molecules of the bowl‐shaped halogen‐bond acceptor, N‐cyclohexyl ammonium resorcinarene chloride 1 , to form the dimeric capsule [(1,4‐dioxane)₃@ 1 ₂(I₂)₂]. The dimeric capsule is constructed solely through halogen bonds and has a single cavity (V=511 ų) large enough to encapsulate three 1,4‐dioxane guest molecules.     

Synthesis and spectroscopic characterization of water-soluble Mn-doped ZnO(x)S(1-x) quantum dots

A non-cadmium and water-soluble Mn-doped ZnO(x)S(1-x) QDs was synthesized with denatured bovine serum albumin (dBSA) as stabilizer under nitrogen atmosphere, and the as-prepared products were characterized by X-ray powder diffraction (XRD), UV-vis absorption spectroscopy, fluorescence (FL) emission spectroscopy, high resolution transmission electronmicroscopy (HRTEM) and Raman spectrum. XRD patterns indicate that the Mn-doped ZnO(x)S(1-x) QDs have a zinc-blende structure, and that manganese emerges in the form of divalent manganese (Mn(2+)) and trivalent manganese (Mn(3+)) (the intermediate of the reaction). The size of Mn-doped ZnO(x)S(1-x) QDs is about 3.2±0.7 nm according to HRTEM imaging. The FL spectra reveal that the Mn-doped ZnO(x)S(1-x) QDs have two distinct emission bands: the defect-related emission and the Mn(2+)-related emission, which exhibit a competing process. A good FL signal of the transition of Mn(2+) ((4)T(1)-(6)A(1)) is observed when the doping amounts are 1.0% and 20% respectively, and the as-prepared solutions are stable for more than 6 months at 4°C. This method has the advantages of good stability and environment-friendly stabilizer, for involving no heavy metal ions or toxic reagents.     

Study on the performance of LiMn2O4 using spent Zn–Mn batteries as manganese source

Recycling spent Zn–Mn batteries by synthesizing the products with high added value is very active internationally. In this work, we have successfully synthesized the spinel LiMn₂O₄ cathode materials for rechargeable lithium-ion batteries by simple sol–gel method using the manganese source that is recovered from spent Zn–Mn batteries through hydrometallurgy recycling technology. The influence of sintering temperature on the structure, the morphological properties, and the electrochemical properties of the product is investigated. The results show that spinel LiMn₂O₄ prepared at 700 °C has the best comprehensive performance. Moreover, the electrochemical performance of spinel LiMn₂O₄ has been further optimized by Co-ion doping.     

Determination of trypsin activity using a gold electrode modified with a nanocover composed of graphene oxide and thionine

We report on an electrochemical method for the determination of the activity of trypsin. A multi-functional substrate peptide (HHHAKSSATGGC-HS) is designed and immobilized on a gold electrode. The three His residues in the N-terminal are able to recruit thionine-loaded graphene oxide (GO/thionine), a nanocover adopted for signal amplification. Once the peptide is cleaved under enzymatic catalysis by trypsin (cleavage site: Lys residue), the His residues leave the electrode, and the GO/thionine cannot cover the peptide-modified electrode anymore. Thus, the changes of the electrochemical signal of thionine, typically acquired at a voltage of -0.35 V, can be used to determine the activity of trypsin. A detection range of 1 × 10⁻⁴ to 1 U, with a detection limit of 3.3 × 10⁻⁵ U, can be achieved, which is better than some currently available methods. In addition, the method is highly specific, facile, and has the potential for the detection of trypsin-like proteases.

Graphene oxide was adopted as a nanocover for the development of a sensitive electrochemical method to detect the activity of trypsin.

     

人面果树皮中口 山 酮 化合物及其DPPH自由基的清除活性

从人面果乙酸乙酯提取物中分离出5个新的口 山 酮 化合物garcinenone A (1), B (3), C (4), D (7) and E (8)和7个已知化合物,其结构经过波谱技术,特别是2D-NMR技术来鉴定。Jacareubin (2), 1,4,6-trihydroxy-5-methoxy-7-(3-methyl-2-buteny1)xanthone (6), subeliptenone B (11) 和symphoxanthone (12)为首次从该植物中分离出来。在DPPH自由基的清除活性实验中,所有的化合物都显示抗氧化活性,其IC50的值在 6.0-23.2 mM。结果表明人面果是潜在的有前景的天然抗氧化剂。     

DNA‐Hybrid‐Gated Multifunctional Mesoporous Silica Nanocarriers for Dual‐Targeted and MicroRNA‐Responsive Controlled Drug Delivery

The design of an ideal drug delivery system with targeted recognition and zero premature release, especially controlled and specific release that is triggered by an exclusive endogenous stimulus, is a great challenge. A traceable and aptamer‐targeted drug nanocarrier has now been developed; the nanocarrier was obtained by capping mesoporous silica‐coated quantum dots with a programmable DNA hybrid, and the drug release was controlled by microRNA. Once the nanocarriers had been delivered into HeLa cells by aptamer‐mediated recognition and endocytosis, the overexpressed endogenous miR‐21 served as an exclusive key to unlock the nanocarriers by competitive hybridization with the DNA hybrid, which led to a sustained lethality of the HeLa cells. If microRNA that is exclusively expressed in specific pathological cell was screened, a combination of chemotherapy and gene therapy should pave the way for a targeted and personalized treatment of human diseases.     

含酰亚胺骨架的大环化合物合成、结构及其对阴离子的识别研究

在磷酸催化作用下,采用前体二胺N,N’-(2-胺基苯基)-2,6-二甲酰亚胺吡啶(1)和前体二醛1,4-二(2’-甲酰苯氧基)丁烷(2)进行缩合作用得到[1+1]Schiff碱大环化合物3,进一步将Schiff碱大环3还原得到饱和大环4.并采用1H NMR,IR,质谱和元素分析等技术对大环3和4的组成进行了表征.采用X射线单晶衍射技术测定了Schiff碱大环3的晶体结构,结果表明大环3具有扭曲的"8"字形结构.采用UV-vis光谱滴定技术对大环与系列阴离子的键合作用进行了考察,结果表明,Schiff碱大环3对F-离子有明显的选择性识别作用,并测定了该配位反应的配位比和平衡常数.     

Synthesis,structure and biological activities of [α‐(alkylcarbonyl)‐2‐(1,2,4‐triazol‐1‐yl)]ethyl‐N,N‐dialkydithiocarbamate derivatives

Seven 1,2,4‐triazole compounds containing the N,N‐dialkyldithiocarbamate group were designed and synthesized. Their structures were identified using infrared spectroscopy, element analysis, ¹H NMR spectroscopy and mass spectrometry, and in two cases by single crystal X‐ray diffraction. The result of the biological test showed that the seven compounds all have fungicidal and plant growth‐regulating activities.