羧甲基牛膝多糖的制备、结构及生物活性研究

在NaOH水溶液中,以ClCH_2COOH为羧甲基化试剂,对牛膝多糖(AbPS)进行了羧 甲基化,粗产物经DEAE-Cellulose及Sephadex G-25两次柱层析纯化,得到羧甲基 牛膝多糖(CM-AbPS)纯品,经高效液相法（HPLC）及毛细管电泳法（CE）检测表明 具有较好的均一性,并通过样品甲基化和GC-MS分析,对羧甲基牛膝多糖链中羧甲 基的分布进行了研究,结果表明羧甲基牛膝多糖中羧甲基主要取代的糖链中呋喃果 糖的4-位上。该产物具有抗肿瘤活性。     

Indirect Transformation of Coordination‐Polymer Particles into Magnetic Carbon‐Coated Mn3O4 (Mn3O4@C) Nanowires for Supercapacitor Electrodes with Good Cycling Performance

Carbon‐coated Mn₃O₄ nanowires (Mn₃O₄@C NWs) have been synthesized by the reduction of well‐shaped carbon‐coated bixbyite networks and characterized by TEM, X‐ray diffraction, X‐ray photoelectron spectroscopy, and electrochemical experiments. To assess the properties of 1D carbon‐coated nanowires for their use in supercapacitors, cyclic voltammetry and galvanostatic charging–discharging measurements were performed. Mn₃O₄@C NWs could be charged and discharged faster and had higher capacitance than bare Mn₃O₄ nanostructures and other commercial materials. The capacitance of the Mn₃O₄@C NWs was 92 % retained after 3000 cycles at a charging rate of 5 A g^?1. This improvement can be attributed to the carbon shells, which promote fast Faradaic charging and discharging of the interior Mn₃O₄ core and also act as barriers to protect the inner core. These Mn₃O₄@C NWs could be a promising candidate material for high‐capacity, low‐cost, and environmentally friendly electrodes for supercapacitors. In addition, the magnetic properties of the as‐synthesized samples are also reported to investigate the influence of the carbon coating.     

空气中肼的流动注射化学发光分析

研究了肼在碱性条件下与鲁米诺和高磺酸钾产生化学发光行为，建立了流动注射化学发光测定痕量肼的新方法。肼的浓度在１．０×１０＾－８－１．０×１０＾－６ｇ／ｍＬ范围内与化学光强度成线性关系；检出限为４×１０＾－９ｇ／ｍＬ；相对标准偏差小于３％。     

胍变及脲变α-淀粉酶的研究 Ⅰ.用高效疏水色谱法研究变性机理和复性效率

用疏水性强弱不同的两种色谱柱对７．０ｍｏｌ／Ｌ盐酸胍及８．０ｍｏｌ／Ｌ脲变性的α－淀粉酶变体和在疏水色谱介质表面上折叠的中间体进行了分离和复性。通过研究和比较发现，两者的变性机理和形成折叠中间体的个数以及复性效率均不相同。在用疏水性较弱的疏水色谱柱对脲变α－淀粉酶的折叠中间体进行分离时，得到了疏水性接近连续的、数目很多的中间体。用疏水性较强的疏水色谱柱对胍变α－淀粉酶进行复性的效果较好。还研究了柱温变化对其折叠、分离效果和复性效率的影响。     

Screening interaction between ochratoxin A and aptamers by fluorescence anisotropy approach

By taking advantage of the intrinsic fluorescence of ochratoxin A (OTA), we present a fluorescence anisotropy approach for rapid analysis of the interactions between OTA and aptamers. The specific binding of OTA with a 36-mer aptamer can induce increased fluorescence anisotropy (FA) of OTA as the result of the freedom restriction of OTA and the increase of molecular volume, and the maximum FA change is about 0.160. This FA approach enables an easy way to investigate the effects of buffer compositions like metal ions on the affinity binding. FA analysis shows the interaction between OTA and aptamer is greatly enhanced by the simultaneous presence of Ca²⁺ and Na⁺, while the binding affinity of aptamer decreases more than 18-fold when only Ca²⁺ exists, and the binding is completely lost when Ca²⁺ is absent. Crucial region of the aptamer for binding can be mapped through FA analysis and aptamer mutation. The demonstrated FA approach maintains the advantages of FA in simplicity, rapidity, and robustness. This investigation will help the development of aptamer-based assays for OTA detection in optimizing the binding conditions, modification of aptamers, and rational design.

Investigation into the crystal structure of bis(pyridine)-bis(trichloroacetato) copper(II) and its electrophotochemical properties

A novel chained Cu(II) complex was synthesized from trichloroacetato copper(II) and pyridine in ethanol solvent, and characterized by elemental analysis and infrared (IR) spectroscopy. The special crystal structure of the Cu(II) complex was determined by X-ray single-crystal diffraction. The results indicate that a chained structure of the Cu(II) complex formed through intermolecular hydrogen bonds. Cu(CCl₃COO)₂(C₅H₅N)₂(H₂O) was monoclinic, with unit cell P21/c and cell parameters as follows: a = 14.389(3) Å, b = 7.1911(14) Å, c = 23.107(8) Å, V = 2,257.5(10) Å³, Z = 4, M _r = 564.51, D _c = 1.661 mg/m³, T = 293(2) K, F(000) = 1,124, μ(Mo K_α) = 1.704 mm^?1, R = 0.0984, and ωR = 0.2791. The electrochemical behavior of the Cu(II) complex on a glassy carbon working electrode determined by cyclic voltammetry showed the electrochemical activity of the title compound at 0.2 to ?0.3 V (versus SCE) in NH₃–NH₄Cl buffer solution (pH 9.2), and the redox peak current of the complex had a good linear relationship with the square root of the scan rate in the range 0.02–0.2 V/s.     

On‐chip protein isoelectric focusing using a photoimmobilized pH gradient†

An immobilized pH gradient was directly constructed on the inner wall of a microfluidic chip channel by photoimmobilizing focused carrier ampholytes onto the wall. A mixture of carbonic anhydrase, myoglobin, and trypsin inhibitor was successfully isoelectric‐focused and separated with good linearity between the pI values of proteins and the location of the focused bands. Furthermore, coating methods for the resistance of protein nonselective adsorption and simultaneously for pH gradient photocoupling were screened. The PEG‐silane coating method was found to be better than the cross‐linked polyacrylamide coating and aminosilane modification methods. Finally, based on the open tubular column mode of carrier ampholytes’ immobilization and effective antiadsorption coating, the immobilized pH gradient was reused and the chip was recycled for the first time. By virtue of its remarkable features including simplicity, convenience, high efficiency of protein enrichment and separation, and potential for coupling site‐selective IEF with other analytical or separation techniques, this novel method promises to be useful in several applications related with zwitterionic biomolecules.     

An Independent 1D Single‐Walled Metal–Organic Nanotube Transformed from a 2D Layer Exhibits Highly Selective and Reversible Sensing of Nitroaromatic Compounds

The syntheses and structures of two new Zn^II complexes, a 2D graphite‐like layer {[Zn(PIA)H₂O] ? H₂O}_n ( 1 ) and an independent 1D single‐walled metal–organic nanotube (SWMONT) {[Zn₂(PIA)₂(bpy)₂] ? 2.5 H₂O ? DMA}_n ( 2 ), have been reported based on a “Y”‐shaped 5‐(pyridine‐4‐yl)isophthalic acid ligand (H₂PIA). Interestingly, the 2D graphite‐like layer in 1 can transform into the independent 1D SWMONT in 2 with addition of 2,2′‐bipyridine (bpy), which represents the first successfully experimental example of an independent 1D metal–organic nanotube generated from a 2D layer by a “rolling‐up” mechanism.     

Anisotropic Cu@Cu-BTC core-shell nanostructure for memory device

The activity and stability of Cu nanostructures strongly depend on their sizes, morphology and structures.Here we report the preparation of two-dimensional(2 D) Cu@Cu-BTC core-shell nanosheets(NSs). The thickness of the Cu NSs could be tuned to sub-10 nm through a mild etching process, in which the Cu-BTC in situ grow along with the oxidation on the surface of the Cu NSs. This unique strategy can also be extended to synthesize one-dimensional(1 D) Cu@Cu-BTC nanowires(NWs). Furthermore, the obtained Cu@Cu-BTC NSs could be applied as an effective material to the memory device with the write-onceread-many times(WORM) behavior and the high I_(ON)/I (OFF) ratio(2.7 × 10~3).     

Divergent total synthesis of aspinolides B,E and J

Stereoselective total synthesis of aspinolides B, E and J, naturally occurring 10-membered lactones, were accomplished by divergent strategies starting from the commercially available 2,3-O-isopropylidene-d-ribose and methyl d-lactate. The synthesis features rapid access to the both key fragments from chiral pool and the formation of 10-membered ring lactones containing trans double bond employing cross-metathesis reaction (CM) and intramolecular Shiina macrolactonization.