Energy basis of recognition of base pair for platinum-based antitumour drug ZD0473 and cisplatin

Platinum-based antitumour drug ZD0473 was designed to reduce the cisplatin resistance to the tumor cells. In this paper, the mixed method of molecular mechanics and quantum chemistry, HF/lanl2dz// MM/uff and B3LYP/lanl2dz//6-31G*, are used to investigate the differences between four types of GG, 3′AG5′, 3′GA5′, and AA complexes, which are formed from four discrete DNA fragments recognized by ZD0473 and cisplatin. The results show that the binding interaction of both ZD0473 and cisplatin drugs with the GG base pair is much stronger than with other base pairs, namely the recognition capability of such drugs to the GG base pair is more considerable. Moreover, the interaction of four complexes of ZD0473 with DNA fragments is stronger than that of cisplatin with corresponding DNA fragments, which indicates the stronger binding capability of ZD0473 with DNA fragments and high antitumour activity of ZD0473. The main reason for easier forming of 3′GA5′ complex than the 3′AG5′ one is that the drug molecule prefers to bind with a single G base to form a monoligand compound firstly; then the con- figuration transformation from such monoligand compound to the bi-ligand one is limited.     

An efficient way to coupling amine with derivatives of steric N-Boc-pyrrolidine-2-carboxylic acid

An efficient way to coupling amine with the derivatives of steric N-Boc-pyrrolidine-2-carboxylic acid was reported in this paper.We have found that the synthesis of derivatives is problematic with the commonly used DCC/HOBT method.As a substitute,themixed anhydride method was adopted.A series of 6-(3-nitroguanidino)hexanamidopyrrolidine derivatives were prepared with thismethod.     

新颖的镧-2-氟苯甲酸及2，2′-联吡啶配合物的合成与晶体结构

2-fluorobenzoic acid (2-HFBA) and 2,2′-bipyridine (2,2′-bpy) was used as ligands to react with lanthanum to obtain a complex, [La(2-FBA)₃·(2,2′-bpy)]₂. The structure of the complex contains three independent molecules. In two of them, the two central metal ions are connected together through four 2-FBA groups by bidentate bridging and chelating-bridging two modes. In another, the two central metal ions are connected together through four bidentate bridging 2-FBA groups. CCDC: 237658.     

Functional Mechanism of Resveratrol in Inhabiting Growth of Cells Is174t and Its Mechanism in Subcutaneously Transplanted Tumor of Nude Mice

To explore the functional mechanism of Resveratrol against colon cancer cells ls174t and the growth of colon cancer tissue of tumor-bearing mice, MTT method was used to observe the functions of resveratrol for inhibition against cells ls174t in vitro. Transmission electron microscope was used to observe the cell apoptosis. FCM assay was performed to measure the change of the cell apoptosis rate and of cell cycle. RT-PCR method was used to detect the expressions of bcl-2 and bax mRNA. Western blot method was used to detect the expressions of bcl-2 and bax protein. Ceils ls174t were transplanted subcutaneously to nude mice to observe the effect of resveratrol on the growth of subcutaneously transplanted tumor, RT-PCR method was used to detect the expressions of bcl-2 and bax mRNA in the tumor tissue. Western blot method was used to detect the expressions of bcl-2 and bax protein in the tumor tissue. Resveratrol has an effect of inhibiting proliferation of cells ls174t in vitro（P〈0.01）. It is able to induce the apoptosis of cells ls174t, causing the decrease in the expression of bcl-2 and the increase in the expression of bax. Resveratrol could inhibit the growth of subcutaneously transplanted tumor of nude mice（P〈0.05）, causing the decrease in the expression of bcl-2 and the increase in the expression of bax. Resveratrol can inhibit the growth of cells 174t and the growth of subcutaneously transplanted tumor. The mechanism is possibly related to the induction of the cell apoptosis and the regulation of bcl-2/bax expression.     

新颖的镧-2-氟苯甲酸及2,2′-联吡啶配合物的合成与晶体结构(英文)

2-fluorobenzoic acid (2-HFBA) and 2,2′-bipyridine (2,2′-bpy) was used as ligands to react with lanthanum to obtain a complex, [La(2-FBA)3·(2,2′-bpy)]2. The structure of the complex contains three independent molecules. In two of them, the two central metal ions are connected together through four 2-FBA groups by bidentate bridging and chelating-bridging two modes. In another, the two central metal ions are connected together through four bidentate bridging 2-FBA groups.     

Electrochemical Oxidation of Chlorimuron-ethyl on Ti/SnO2-Sb2O5/PbO2 Anode for Waste Water Treatment

<正>The electrochemical oxidation of chlorimuron-ethyl on Ti/SnO_2-Sb_2O_5/PbO_2 electrode was studied by cyclic voltammetry. The electrochemical behaviour of the electrode in a sodium sulfate solution and in the mixture solution of sodium sulfate and chlorimuron-ethyl was studied.The experimental results of cyclic voltammetry show that the acidic medium was suitable for the efficient electrochemical oxidation of chlorimuron-ethyl.Some electro-generated reagent was formed in the electrolysis process and chlorimuron-ethyl could be oxidized by the electro-generated reagent.A Ti/SnO_2-Sb_2O_5/PbO_2 electrode was used as the anode and the electrolysis experiment was carried out under the optimized conditions.The electrolysis process was monitored by UV-Vis spectrometry and high performance liquid chromatography(HPLC),and the chemical oxygen demand(COD) was determined by the potassium dichromate method.The mechanism of chlorimuron-ethyl to be oxided was studied primarily by the cyclic voltammetry and UV-Vis spectrometry.The results of electrolysis experiment demonstrate the possibility of the electrode to be used as an anode for the electrochemical treatment of chlorimuron-ethyl contained in waste water.     

Thioxanthene-9-thione Mediated MMA Polymerization

In the "cycloketyl radical mediated living polymerization"(CMP) process, a cycloketyl compound, [9,9′]bixanthenyl-9,9′ diol(BIXAN) was ultilized as initiator and mediator. The cycloketyl(CK) radical was used as the dormant radical to achieve the increase of molecular weight. Herein, a series of cycloketyl thioketones were synthesised by Lawesson's reagent by one step reaction with high yeild,and we found that, when a special cycloketyl thioketone compound, thioxanthene-9-thione(TXT), was added to a routine radical polymerization system, TXT could capture chain radical, and simultaneously formed an radical analogous to CK radical in structure,which could trigger the growth of polymer chains. This simple system was efficient to initiate the polymerization of methyl methacrylate(MMA) and in all cases the molecular weights increased with the increase of conversions. By the end-group analysis with 1 H-NMR and MALDI-TOF MS, it was confirmed that the P-STXT radical was used to control the polymerization. The re-initiating reactions were achieved when PMMA was used as the macro-initiator.     

Fabrication of Novel Scaffolds Containing Collagen-I/Polylactic Acid/Nanohydroxyapatite via Co-electrospinning Methods

<正>A novel scaffold containing collagen-Ⅰ/polylactic acid(PLA)/nanohydroxyapatite(nHA) was prepared via co-electrospinning method.Different target substrates were used to improve the collection efficiency of this scaffold. The properties of the novel scaffold were compared with those of conventionally prepared ones.Compared to conventional method,the modified method was more efficient in producing the scaffold.Moreover,the porosity,thickness, and morphology of the novel scaffold were better than those of scaffolds prepared by conventional methods. The properties of collagen-Ⅰ,collagen-Ⅰ/PLA and collagen-Ⅰ/PLA/nHA scaffolds were also compared.Diameters of the electrospun fibers ranged from 180 to 405 nm,and roughness was present on the surface of the fibers due to the deposition of crystals of nHA along the long axis of the fibers.The fibers of the collagen-Ⅰ/PLA/nHA scaffold and the fibers of natural bone tissue had similar structure.     

SITE-SPECIFIC DELETION OF THE N-TERMINAL SEGMENTS FROM EcoRI ENDONUCLEASE USING THE POLYMERASE CHAIN REACTION

We developed a general and efficient method for directing the deletions of DNA sequences of any lengths using polymerase chain reaction (PCR). The method was based on in vitro amplification of target sequences with site-specific deletions, Klenow end-flushing and blunt-end cloning. As an example, it was used to delete the restriction gene encoding EcoRI endonuclease, resulting in plasmids expressing two truncated forms. Assays using SDS-PAGE and gel retardation revealed the important role of the amphipathic helix (29-43) of the EcoRI endonuclease in binding to its cognate substrate.     

An efficient method for preparing the sphingosine-1-phosphate receptor agonist, KRP203-phosphate

An efficient method for mono-phosphorylation of 2(KRP203)using cbz-protection,dibenzylphosphoryl chloride and TMSI affording 2-P(KRP203-P)was developed.We applied the present method to the synthesis of KRP203 phosphate analogs which were difficult to produce through tradition procedures.     

Potassium dihydrogen phosphate catalyzed one-pot synthesis of 2,4,5-triaryl-1H-imidazoles

<正>A simple and efficient method has been developed;benzil/benzoin undergoes smooth condensation with various substituted aldehyde and ammonium acetate in the presence of potassium dihydrogen phosphate(KH_2PO_4) under mild reaction conditions to afford the corresponding trisubstituted imidazole in excellent yields.The method for synthesis of product,the reaction mixture was reflux in ethanol for 40-90 min.The present method is simple,efficient,and cost-effective.     

A rapid protein sample preparation method based on organic-aqueous microwave irradiation technique

Fast and efficient sample preparation methods are a prerequisite for protein identification in bottom-up proteomics. Here, an innovative microwave irradiation sample preparation method was developed based on an optimized organic-aqueous solvent system for protein identification. Specifically, protein solutions containing high-concentration acetonitrile were subjected to 5 min microwave irradiation. After cooling down, trypsin was added and the digestion was performed with 30 s microwave irradiation, and the resulting peptides were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS). A shortened processing time of only 5.5 min is needed with this method(more than 12 h is necessary in the traditional overnight protein sample preparation). Moreover, due to the absence of urea and other chaotropic reagents, the digests can be readily identified by MALDI-TOF MS. When an assessment of this method was performed by digesting a model protein BSA, 69% ± 3% sequence coverage corresponding to 47 ± 3 peptides was obtained, which shows better protein identification than that from the standard overnight protein sample preparation method(51% ± 2% sequence coverage and 23 ± 1 peptides). Another model protein α-casein was used for the analysis of protein phosphorylation with the newly developed method that yielded 4 phosphopeptides with 8 phosphorylation sites, whereas 3 phosphopeptides with 2 phosphorylation sites were obtained from the traditional overnight approach. Moreover, the organic-aqueous microwave irradiation method provides effective digestion for proteins down to fmol.     

The efficient synthesis of 14-alkyl or aryl 14H-dibenzo[a,j]xanthenes catalyzed by bismuth(Ⅲ)chloride under solvent-free conditions

An efficient method for the synthesis of 14-alkyl or aryl 14H-dibenzo[a,j]xanthene derivatives by the reaction of β-naphthol,and aldehydes in the presence of a catalytic amount of bismuth（Ⅲ） chloride（BiCl₃） under solvent-free conditions at 110℃is described.Aliphatic and aromatic aldehydes were used in the reaction and in all cases the desired products were synthesized successfully.This reaction was studied under different temperatures;the maximum yield was obtained in a short reaction period at 110℃.The method offers the advantages of high yields,short reaction times,simplicity and easy workup compared to the conventional method of syntheses.     

Pt/Mo chalcogenide composite deriving from Pt-Mo6S8 by high temperature shock for enhanced HER performance

Highly efficient catalysts for electrolysis of water are crucial to the development of hydrogen energy which is helpful to carbon neutralization. Recently, high temperature shock(HTS), with advantage of rapid speed, universality and scalable production, has been a promising method in synthesis of nanomaterials.In this paper, HST was used to treat low Pt loading Mo₆S₈ for enhanced water splitting performance. Impressively, the optimized MoS₂/MoO₂/Mo     

Synthesis and Characterization of a Novel Copoly(aryl ether ketone) Containing 4,4′-Biphenyl-bis[4-phthalazin-1(2H)-one] moiety

A new monomer of 4,4′-biphenyl-bis[4-phthalazin-1(2H)-one] was synthesized from biphenly and phthalic anhydride,and a novel copoly(aryl ether ketone)(PPEK) was synthesized from 2,2-bis(4-hydroxyphenyl)-propane(BPA),4,4′-biphenyl-bis-[4-phthalazin-1(2H)pne],4,4′-difluorodiphenylketone(DFK).The monomer and copolymer were characterized by FT-IR and ^1H-NMR.DSC and TGA were used to the novel polymer.     

Analysis of Ginsenosides by SPE-HPLC and Its Application to Quality Control

<正>A rapid and effective method,solid phase extraction coupled with high performance liquid chromatography (SPE-HPLC),was applied to the separation and analysis of ginsenosides.Waters OASIS HLB was used for concentrating and purifying samples and Alltima C_(18)(53 mm×7 mm,3μm) chromatography column was used for separating ginsenoside Rg_1,Re,Rb_1,Rc,Rb_2 and Rd.These ginsenosides were analyzed within 20 min in our gradient elution process and the equilibrium time of the chromatography column cost only 5 min.Moreover,there was no obvious baseline drift in our experiment.This method was used to analyze the contents of ginsenosides in different ginseng products for quality control.Four ginseng products were studied,including two kinds of capsules,one kind of tablet and one kind of injection.The results show that the method developed in this paper had good accuracy,linearity and precision.Therefore,this method could be applied in quality control of ginseng products.     

Effect of Solvents on Oxidation of 1, 1′-Bi-2-naphthol

A novel biomimetic catalyst of complex Cu (p-OTs)2/ethanolamine (1 : 1 ) was used to oxidize 1, 1′-bi-2naphthol into xanthene derivatives with a relative high yield in a mixed solvents of dimethyl sulfoxide (DMSO) and CH3OH. The studies on the effect of some solvents on the yield of xanthene derivatives indicates that the yield reduces dramatically with the increase of the content of H2O in the mixed solvents of H2O and DMSO. No product can be obtained when the content of H2O is up to 70%. The cyclic voltammetric study demonstrated that the copper ion in complex Cu(p-OTs)2/ethanolamine(1:1) is reduced via a twostep one-electron reduction process from Cu (Ⅱ) to Cu in the mixture of DMSO and H2O. Water as a poor solvent in respect to the reactants probably hampered the coordination of 1, 1′-bi-2-naphthol to copper/amine complex and led to the insufficient catalytic efficiency of complex Cu(p-OTs),/ethanolamine(1:1).     

An Efficient Synthesis of Aromatic 1-Hydroxymethylene-1,1-bisphosphonates from Aldehydes

A simple and efficient procedure for synthesis of 1-hydroxymethylene-1,1-bisphosphoates from aldchydes is described.This method was applied to the synthesis of novel catechol substituted bisphosphonates as the anti-osteoporosis agents.     

Magnetic graphene nanocomposite as an efficient catalyst for hydrogenation of nitroarenes

Graphene-Fe₃O₄ nanocomposite（G-Fe₃O₄） was synthesized by a chemical co-precipitation method which was used as an efficient catalyst for the reduction of nitroarenes with hydrazine hydrate.The method has been applied to a broad range of compounds with different properties and the yields were in the range of 75%-92%.The G-Fe₃O₄ catalyst can be readily recovered and reused 5 times without significant loss of the catalytic activity.     

A novel PdNi/Al2O3 catalyst prepared by galvanic deposition for low temperature methane combustion

Galvanic deposition method was used to prepare the Pd/Ni-Al2O3-GD catalyst for the combustion of methane under lean conditions. The new catalyst and compared catalysts (Pd/Al2O3-IW, Pd-Ni/Al2O3-IW, Pd/Ni-Al2O3-IW) prepared by incipient wetness impregnation were characterized by N2-physisorption, XRD and TEM to clarify particle size and size distribution of palladium species. Combined O2-TPD and XPS results with the catalytic data, it shows that the surface palladium species with low valence exhibits better combustion performance due to their stronger interaction with support. The results indicate that the galvanic deposition method is an effective route to prepare efficient catalyst for methane combustion, and it also provides useful information for improving the present commercial catalyst.