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991.
992.
You-Min Ying Zha-Jun Zhan Zhi-Shan Ding Wei-Guang Shan 《Chemistry of Natural Compounds》2011,47(4):541-544
A chemical study of metabolites of the strain Penicillium sp. P-1, an endophyte from the stems of Huperzia serrata, furnished a new chromone derivative, (2S)-2,3-dihydro-7-hydroxy-6,8-dimethyl-2-[(E)-prop-1-enyl]- chroman-4-one (1), an enantiomer of a known compound, and seven known compounds 2–8. The structure and absolute configuration of 1 were established using spectroscopic methods, including extensive 2D NMR and CD analyses. Cytotoxic activity of compounds
1–3 against HeLa and HepG2 cell lines were evaluated, in which compounds 2 and 3 exhibited marked cytotoxic activity against HeLa cells. 相似文献
993.
Wang W Wang HY Wei W Xiao ZG Wan Y 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(48):13461-13472
We demonstrate the self-assembling and size-selective synthesis of uniform and highly dispersed Ni or NiO nanoparticles with diameters below 12 nm embedded in ordered mesoporous carbon or polymer frameworks. Self-assembly is induced by evaporation of the solvent from a mixture of metal-containing liquid crystalline (LC) mesophases of triblock copolymer and transition metal nitrate hydrate, and the carbon source is low-polymerized phenolic resol. Characterization by XRD, N(2) sorption isotherms, TEM, HRSEM, ICP-AES, TG, and XPS techniques has indicated an ordered 2D hexagonal mesostructure, high surface areas between 524 and 721 m(2) g(-1), uniform pore sizes of about 4.0 nm, large pore volumes ranging from 0.34 to 0.58 cm(3) g(-1), and metal contents ranging from 0.6 to 10.0 wt%. There is a high degree of dispersion, and a small size of nanoparticles throughout the whole framework, without aggregation outside of the pores due to the confinement effect of the mesoporous ordered matrix. The mesoporous solids show excellent adsorption properties for dyes and permit an easy magnetic separation procedure. This method is expected to be applicable to other mesoporous transition metal(oxide)-containing carbon catalysts. 相似文献
994.
James R. Durig Savitha S. Panikar Keith A. GlennYa Ying Zheng Gamil A. Guirgis 《Vibrational Spectroscopy》2011,55(2):250-257
Infrared and Raman spectra (3500-60 cm−1) of gas and/or liquid and solid 1-chloro-1-silacyclopentane (c-C4H8SiClH) have been recorded and the vibrational data indicate the presence of a single conformer with no symmetry which is consistent with the twisted form. Ab initio calculations with a variety of basis sets up to MP2(full)/aug-cc-pVTZ predict the envelope-axial and envelope-equatorial conformers are saddle points with nearly the same energies but much lower in energy than the planar conformer. Density functional theory calculations by the B3LYP method predicts slightly lower energies for the two envelope forms and considerably lower for the planar form. By utilizing the MP2(full)/6-31G(d) calculations the force constants, frequencies, infrared intensities, band contours, Raman activities, and depolarization values have been obtained to support the vibrational assignment. Estimated r0 structural parameters have been obtained from adjusted MP2(full)/6-311 + G(d, p) calculations. These experimental and theoretical results are compared to the corresponding quantities of some other five-membered rings. 相似文献
995.
Yu X Lu S Yang Y Li X Yi P 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,83(1):609-613
The fluorescence and ultraviolet spectroscopies were explored to study the interaction between N-confused porphyrins-edaravone diad (NCP-EDA) and bovine serum albumin (BSA) under simulative physiological condition at different temperatures. The experimental results show that the fluorescence quenching mechanism between NCP-EDA and BSA is a combined quenching (dynamic and static quenching). The binding constants, binding sites and the corresponding thermodynamic parameters (ΔG, ΔH, and ΔS) of the interaction system were calculated at different temperatures. According to F?rster non-radiation energy transfer theory, the binding distance between NCP-EDA and BSA was calculated to be 3.63 nm. In addition, the effect of NCP-EDA on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy. 相似文献
996.
A new label-free amperometric immunosensor was developed for detection of carcinoembryonic antigen (CEA) based on chitosan-ferrocene (CS-Fc) and nano-TiO2 (CS-Fc + TiO2) complex film and gold nanoparticles-graphene (Au-Gra) nanohybrid. CS-Fc + TiO2 composite membrane was first modified on a bare glass carbon electrode. Then Au-Gra nanohybrid was formed on the CS-Fc + TiO2 membrane by self-assembly strategy. Next, further immobilization of anti-CEA was constructed according to the strong interaction between Au-Gra and the amido groups of anti-CEA. Since Au-Gra nanohybrid films provided a congenial microenvironment for the immobilization of biomolecules, the surface coverage of antibody protein could be enhanced and the sensitivity of the immunosensor has been improved. The good electronic conductive characteristic might be attributed to the synergistic effect of graphene nanosheets and Au NPs. The modified process was characterized by scanning electron microscope (SEM) and cyclic voltammetry (CV). Under optimized conditions, the resulting biosensor displayed good amperometric response to CEA with linear range from 0.01 to 80 ng/mL and a detection limit of 3.4 pg/mL (signal/noise = 3). The results demonstrated that the immunosensor has advantages of high conduction, sensitivity, and long life time. This assay approach showed a great potential in clinical applications and detection of low level proteins. 相似文献
997.
Shasha Ying Shubo Du Jia Dong Bi Xuan Ng Chengwu Zhang Lin Li Jingyan Ge Qing Zhu 《中国化学快报》2019,30(1):67-70
A small library of wortmannin based probes was synthesized by installing a clickable handle at C11 site for bioconjugation, and secondary amine and biotin moiety at C20 site to achieve self-activation and cancer target, respectively, to facilitate the analysis of their intracellular effects. 相似文献
998.
The recent progress of wide bandgap (WBG) donor polymers for non-fullerene polymer solar cells (NF-PSCs) were reviewed in detail, which was classified by D-type and D-A type molecular backbones to discuss the related structure-property correlations and put forward an outlook for future innovations. 相似文献
999.
1000.