Epoxy-based azo molecular glasses with four-arm architecture: Preparation,characterization and holographic recording

A series of epoxy-based azo molecular glasses with four-arm architecture was synthesized, characterized and applied to holographic recording.     

混合溶剂对磺化聚苯乙烯水基微乳液体系形态的影响

利用相反转技术制备磺化聚苯乙烯(SPS)水基微乳液,研究发现,通过选择溶剂和控制混合溶剂的组成,可制备不同颗粒形态结构的SPS水基微乳液,并研究了相反转过程、乳液稳定性与混合溶剂组成之间的关系。     

Polymer bound glutamic acid salicylaldehyde Schiff‐base complex ­catalyst for oxidation of olefins with ­dioxygen

The polymer bound Schiff‐base ligand (PS‐SalGlu) has been prepared from polystyrene bound salicylaldehyde and glutamic acid, and its complex (PS‐SalGlu‐Co) has also been synthesized. The polymer ligand and its complex were characterized by infrared spectroscopy, small area X‐ray photoelectron spectroscopy, and inductively coupled plasma‐atomic emission spectro (ICP‐AFS). In the presence of the complex, cyclohexene can be effectively oxidized by molecular oxygen without reductant. The long‐chain linear aliphatic olefins, such as 1‐octene, 1‐decene, 1‐dodecene and 1‐tetradecene, can be directly oxidized by molecular oxygen catalyzed by PS‐SalGlu‐Co, which affords the 1,2‐epoxy alkane. Copyright © 2001 John Wiley & Sons, Ltd.     

Controllable self-assembly of parallel gold nanorod clusters by DNA origami

We demonstrate the self-assembly of three types of parallel gold nanorod clusters using a rod-like DNA origami as the template.     

Performance of the diffusive gradients in thin films technique for measuring Ca and Mg in freshwater

Measurements of the major cations Ca and Mg by the technique of diffusive gradients in thin films (DGTs) were systematically evaluated. The concentration in solution was calculated using Fick’s first law of diffusion from the directly measured flux to the DGT device. A selective cation exchange resin (Bio-Rad Chelex^®100), which has been used extensively with DGT for trace metals, such as Cd²⁺, Cu²⁺ and Ni²⁺, was used for this work.

Elution of Ca and Mg from the resin with 1 M HNO₃ was very reproducible. Measurements of Ca and Mg concentrations in synthetic solutions agreed well with the theoretical predictions. The negative response on uptake caused by lowered pH was investigated. Uptake was found to decline below pH 5. The capacity of the DGT device for Ca and Mg was also investigated to establish maximum deployment times for given concentrations.

Experiments with filtered and modified lake water show that DGT can be used to measure Ca and Mg when trace metals are present in the solution. An in situ deployment of DGT combined with an ultrafiltration study suggest that the Mg concentration measured by DGT is similar to the concentration found in the fraction <1 kDa.     

过渡金属离子与Schiff碱配合物的研究——Ⅰ.双-[N-(4-甲基苯基)水杨醛亚胺]钴(Ⅱ)的晶体结构与电子结构

过渡金属离子与Schiff碱配合物的合成与性质研究始自50年代,并已有不少论文发表。70年代发现Co(Ⅱ)与Schiff碱的配合物具有抗癌和抗肿瘤活性之后,这一领域的研究工作更加活跃,但对其结构和性质关系的研究多数尚通过谱学方法进行,对标题化合物也只有晶胞参数的报导。为了探讨该类化合物的分子结构与生理活性的关系,本文首先报导标题化合物的晶体与分子结构以及其电子结构的量子化学近似计算结果。     

Electrospray liquid chromatography/mass spectrometry fingerprinting of Acanthophis (death adder) venoms: taxonomic and toxinological implications

Death adders (genus Acanthophis) are unique among elapid snakes in both morphology and venom composition. Despite this genus being among the most divergent of all elapids, the venom has been historically regarded as relatively quite simple. In this study, liquid chromatography/mass spectrometry (LC/MS) analysis has revealed a much greater diversity in venom composition, including the presence of molecules of novel molecular weights that may represent a new class of venom component. Furthermore, significant variation exists between species and populations, which allow for the LC/MS fingerprinting of each species. Mass profiling of Acanthophis venoms clearly demonstrates the effectiveness of this technique which underpins fundamental studies ranging from chemotaxonomy to drug design.     

萘降解菌LHJ38生物合成靛蓝的研究

萘降解菌LHJ38在金属盐培养基中加入水杨酸钠诱导培养后能提高其生物合成靛蓝的能力,在LB培养基中加入水杨酸钠反而抑制了其生物合成靛蓝的能力.与LHJ38最适生长pH值不同,LHJ38生物合成靛蓝的最佳pH值范围是8.45—9.45,在pH为8.95的情况下生物合成靛蓝能力是其在pH值为6.95的情况下的两倍.     

Determining the folding and unfolding rate constants of nucleic acids by biosensor. Application to telomere G-quadruplex

Nucleic acid molecules may fold into secondary structures, and the formation of such structures is involved in many biological processes and technical applications. The folding and unfolding rate constants define the kinetics of conformation interconversion and the stability of these structures and is important in realizing their functions. We developed a method to determine these kinetic parameters using an optical biosensor based on surface plasmon resonance. The folding and unfolding of a nucleic acid is coupled with a hybridization reaction by immobilization of the target nucleic acid on a sensor chip surface and injection of a complementary probe nucleic acid over the sensor chip surface. By monitoring the time course of duplex formation, both the folding and unfolding rate constants for the target nucleic acid and the association and dissociation rate constants for the target-probe duplex can all be derived from the same measurement. We applied this method to determine the folding and unfolding rate constants of the G-quadruplex of human telomere sequence (TTAGGG)(4) and its association and dissociation rate constants with the complementary strand (CCCTAA)(4). The results show that both the folding and unfolding occur on the time scale of minutes at physiological concentration of K(+). We speculate that this property might be important for telomere elongation. A complete set of the kinetic parameters for both of the structures allows us to study the competition between the formation of the quadruplex and the duplex. Calculations indicate that the formation of both the quadruplex and the duplex is strand concentration-dependent, and the quadruplex can be efficiently formed at low strand concentration. This property may provide the basis for the formation of the quadruplex in vivo in the presence of a complementary strand.     

Determination of the residue of quizalofop-p-tefuryl in soybean by HPLC

A HPLC method was developed for the analysis of quizalofop-P-tefurylof in soybean. The samples were extracted with methanol-water (volume ratio), The extracts were cleaned up with a column of silica gel. The final residue was detected by HPLC, using a UV detector. The recoveries from the analytical method for soybean were 84.32%–89.25%. Variable coefficients were 0.49%∼1.51%. This method proved to be simple, reliable and accurate. __________ Translated from Chinese Journal of Chromatography, 2005, 23(2)(in Chinese)