Comparative Study on the Inclusion Interaction between meso-Tetrakis（4-N-ethylpyridiniurmyl） porphyrin and β-Cyclodextrin Derivatives

The interaction of β-cyclodextrin (β-CD) and the modified cyclodextrins, hydroxy propyl-β-cyclodextrin (HP-β-CD), sulfobutylether-β-cyclodextrin (SBE-β-CD) and synthesized meso-tetrakis(4-N-ethylpyridiniurmyl)porphyrin (TEPyP) in aqueous solution has been studied by spectroscopic methods systematically. A significant change in fluorescence and absorption properties has been observed in the presence of β-CD, HP-β-CD and SBE-β-CD. The stoichiometry and formation constants have been determined by the steady-state fluorescence technique. The results showed that the β-CD derivatives were prior to the native β-CD and the hydrogen bonding and static electric forces played important roles in the formation of the inclusion complexes. The conformation was further confirmed by NMR spectroscopy.     

Na~+/Ca~(2+) Exchange-mediated La~(3+) Entry in Human Lymphocytes

With extensive applications the rare earth elements to agriculture, medicine and animal husbandry, whether rare earth ions can cross cell membranes and participate in the metabolism of animals and plants is not clear until now. Otherwise, rare earth ions have different interaction fashions to different kinds of cells, therefore, in this study we determined whether La3+ enter human peripheral blood lymphocytes via Na+/Ca2+ exchanger (measured with fura-2).Relative sensitivity of fura-2 to Ca2+…     

Spectroscopic Study of the Interaction of Bu_2SnCl_2 with EHPG

A number of Sn (Ⅳ)complexes have been synthesized since 1980 and tested its anticancer activity1. The simplest complex Bu2SnCl2 has activity to P388 tumor cells. Several metal complexes such as Ru-ind (trans-indazolium (bisindazole) tetrachloro- ruthenate (Ⅲ)) had used transferrin as a drug delivery system, the complexes still exhibit high antitumor activity and lower toxicity2. We use EHPG as a model ligand3 to study the interaction between Bu2SnCl2 and EHPG. EHPGAt first, we stud…     

Cleavage of DNA by a New Mixed-ligand Cu（ Ⅱ ） Complex

Cleavage of DNA pUC19 by [Cu(saldien)(NH3)]C12 (here, saldien=bis(salicylicdene)-diethylenetriamine) was investigated at different pHs, times, concentrations, and 37℃. It wasfound that the copper( Ⅱ ) complex could cleave DNA without added coreactants.     

Synthesis and DNA Cleavage Studies of 2,6-Dimethoxyhydroquinone-3-Mercaptoacetic Acid Conjugates

In previous paper and work, we reported the synthesis and cytotoxicity studies of a novel series of short chain peptide conjugates of the cytotoxic agent 2, 6-dimethoxyhydro -quinone-3-mercaptoacetic acid1 (DMQ-MA). The DMQ-MA is a derivative of 2,6-dimethoxybenzoquinone, which is a natural product of fermented wheat germ and found to have a wide spectrum of cytotoxicity against various tumor cell lines under the synergistic activation of L-ascorbic acid (AH2)2,3. Compared with DMQ, DMQ…     

Efficient Cleavage of DNA by the Novel Copper (II) Complex Derived From 2,2'-Pyridil Ligand

Due to the importance of oxidative degradation of nucleic acids in mutagenesis, carcinogenesis, and aging, a large number of chemical and biological investigations have been recently published1. Artificial metallonucleases have been proven to be efficient tools for the footprinting and sequence-specific targeting of nucleic acids1,2. They usually require high concentrations of the complex and of an external reducing agent (such as dithiothreitol, DTT) to form a reactive species in situ, the f…     

Molecular modeling of the binding mode of chiral metal complexes A- and A-[Co(phen)_2dppz]~(3 ) with B-DNA

Molecular modeling methods have been applied to the structural characterization of the interaction between chiral metal complexes [Co(phen)2dppz]3 (where phen = 1, 10-phenanthroline, dppz = dipyrido[3,2-a: 2', 3'-c]phenazine) and the oligonucleotide (B-DNA fragment). The natures of two kinds of the binding modes, which are currently intense controversy, have been explored. Barton proposed that there is enantio-selective DMA binding by the octahedral complexes and intercalative access by these complexes from the major groove; but Norden suggested that both enantiomers bind extremely strongly to DNA from the minor groove without any noticeable enantio-selectivity. Our results support and extend structural models based upon Norden's studies, and conflict with Barton's model.     

Room Temperature Phosphorescence pH Switch Based on Photo-induced Electron Transfer

In this paper, photoinduced electron transfer(PET)phosphoroionophore,N-(1-bromo-2-naphthylmethyl)-dicthanolamine (BND)was synthesized and its phosphorescent characteristics were studied,The experimental results showed that strong phosphorescence could be observed in β-cyclodextrin apueous solution only at low pH value ,This system combined AND and NOT function to produce a three-input inhibit (INH)logic gate .     

Effect of dextran molecular weight on resonance light-scattering of quantum dots modified with dextran and concanavalin A

The reversible aggregation between dextran-conjugated CdSe quantum dots(Dex-CdSe-QDs) and concanavalin A(Con A) was explored based on the specific affinity of polysaccharide for Con A by resonance light-scattering technique.In this study,the aggregation of Dex-CdSe-QDs induced by Con A and sequential dissociation by glucose was determined over a wide range of dextran molecular mass(10-500 kDa).The results demonstrate that the sensitivity of lectin-dextran-modified-QDs interactions increase with dextran molecular mass,and an optimum dextran molecular mass is 500 kDa.     

Effect of binder on the properties of iron oxide sorbent for hot gas desulfurization

The most difficult problem in hot gas desulfurization in Integrated Coal Gasification Combined Cycle (IGCC) is the pulverization of sulfur removal sorbents. Appropriate binders for hot gas sulfur removal sorbents can solve the pulverization problem. In this paper, six sorbents with binders of different argillaceous minerals were prepared by mechanical mixing method. Desulfurization behavior for hot gas desulfurization sorbents was investigated in a fixed-bed reactor. Result showed that sorbent NTKW2 with binder of clay had a better sulfidation performance. NTKW2 had a more stable performance than other sorbents in the continuous sulfidation-regeneration cycles. Sulfur capacity of sorbent remained the same in each cycle. The desulfurization efficiency and mechanical strength of NTKW2 were the best among the tested sorbents. The behavior of NTKW2 at different temperatures showed different performances, and the best reaction temperature was 550 ℃. Higher heat stability, sulfur capacity and desulfurization efficiency were found on NTKW2 in six continuous sulfidation-regeneration cycles.