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981.
Synthesis of high-quality carbon nanodots from hydrophilic compounds: role of functional groups 总被引:1,自引:0,他引:1
A simple one-pot hydrothermal approach has been demonstrated for the preparation of highly water soluble and photoluminescent carbon nanodots (C-dots) from low-cost organic compounds. We found that the compounds incorporating amino and carboxylic acid groups are suitable for the preparation of highly photoluminescent and water-soluble C-dots. 相似文献
982.
A new azaphilonidal derivative, monapurpyridine A (MPA), has recently been isolated from the fermented products of Monascus purpureus NTU 568. The structure of MPA was elucidated by nuclear magnetic resonance (1H-NMR, 13C-NMR, COSY, HMQC, and HMBC) and other spectroscopic analyses. Biological evaluation revealed that MPA could induce cell death in human breast adenocarcinoma cells MCF-7, and it has no significant toxicity to normal mammary epithelial cells M10. The MTT assay and flow cytometric analysis were employed to investigate cell viability and cell cycle influenced by MPA. Moreover, we used Western blot and caspase activity assay to demonstrate the activation of caspase-3, -8 and -9 resulted from MPA. All evidence supported that MPA was suitable for developing into a chemotherapeutic or chemopreventive agent against breast cancer. 相似文献
983.
CJ Li SY Huang MY Wu YC Chen SF Tsang JH Chyuan HY Hsu 《Molecules (Basel, Switzerland)》2012,17(8):9348-9360
Corchorus olitorius L., is a culinary and medicinal herb, widely used as a vegetable in several countries in Asia. Many studies have shown that C. olitorius contains several antioxidants and exhibits anti-inflammatory and anti-proliferative activities in various in vitro and in vivo settings. Recently, C. olitorius has been approved for its antitumor activity; however, the underlying molecular mechanisms remain unclear. The goal of this study was to investigate the effects of ethanol extract of C. olitorius (ECO) on the growth of human hepatocellular carcinoma (HepG2) cells and gain some insights into the underlying mechanisms of its action. We found that HepG2 cells, treated with ECO for 24 h at a concentration higher than 12.5 μg/mL, displayed a strong reduction in cell viability, whereas normal FL83B hepatocytes were not affected. DNA fragmentation and nuclear condensation were evidenced by the increased subG1 population of ECO-treated HepG2 cells. ECO triggered the activation of procaspases-3 and -9 and caused the cleavage of downstream substrate, poly ADP-ribose polymerase (PARP), followed by down-regulation of the inhibitor of caspase-activated DNase (ICAD) signaling. Moreover, the increased release of cytochrome c from mitochondria with decreased membrane potential demonstrated the apoptosis induced through the caspases cascade. Our findings indicated that ECO might be effective against hepatocellular carcinoma through induction of apoptosis via mitochondria-dependent pathway. 相似文献
984.
Tu YJ Cheng HC Chao I Cho CR Cheng RJ Su YO 《The journal of physical chemistry. A》2012,116(6):1632-1637
Electrochemical properties of substituted free base meso-tetraphenylporphyrins (H(2)T(o,o'-X)PP, H(2)T(o-X)PP, and H(2)T(p-X)PP, where X = OCH(3), CH(3), H, F, or Cl on the phenyl rings) are examined by cyclic voltammetry. When a substituent is located only at the para position of the meso-phenyl group, the difference between the first and second oxidation potentials (ΔE(ox), i.e., E(2)(ox) - E(1)(ox)), is generally significantly smaller than those of the H(2)TPPs with bulky o,o'-substituents on the phenyl group. This trend is elucidated with density functional theory calculations and attributed mainly to the sterically controlled π-conjugation of the meso-phenyl groups to the central porphyrin ring, rather than the often discussed deformation of porphyrin. 相似文献
985.
Hsu IJ Kimmel YC Jiang X Willis BG Chen JG 《Chemical communications (Cambridge, England)》2012,48(7):1063-1065
Pt was deposited onto tungsten carbide powders using atomic layer deposition to produce core-shell catalysts for the hydrogen evolution reaction (HER). The Pt loading on these catalysts was reduced nearly ten-fold compared to a bulk Pt catalyst while equivalent HER activities were observed. 相似文献
986.
Cheng YJ Cheng SW Chang CY Kao WS Liao MH Hsu CS 《Chemical communications (Cambridge, England)》2012,48(26):3203-3205
We report a novel diindenothieno[2,3-b]thiophene ladder-type hexacyclic arene for constructing a donor-acceptor copolymer PDITTDTBT. A device based on PDITTDTBT:PC(71)BM exhibited a high V(oc) of 0.92 V with an impressive PCE of 5.8%, while a PDITTDTBT:DMPCBA-based device showed an extra high V(oc) of 1.14 V. 相似文献
987.
Chou WY Chang J Yen CT Lin YS Tang FC Liu SJ Cheng HL Hsu SL Chen JS 《Physical chemistry chemical physics : PCCP》2012,14(15):5284-5288
The efficiency of small-molecule solar cells critically depends on the match of the junction of the donor and acceptor semiconductors used in these devices to create charged carriers and on the mobility of individual components to transport holes and electrons. In the present study, a 2% efficient bilayer organic solar cell consisting of a p-type semiconductor, pentacene, and an n-type semiconductor, N,N'-diheptyl-3,4,9,10-perylenetetracarboxylic diimide (PTCDI-C(7)), is fabricated. The morphology of PTCDI-C(7) interestingly follows pentacene due to the matched surface energy of these two active layers and the easily deposited PTCDI-C(7) monomers on an inclined plane of the pentacene grains. This condition results in the low trap states in the PTCDI-C(7) film and at the pentacene/PTCDI-C(7) interface for the enhancement of exciton dissociation and carrier transport compared with the photoactive layer comprised of pentacene and N,N-ditridecyl-3,4,9,10-perylenetetracarboxylic diimide (PTCDI-C(13)). The detailed exciton and carrier transport mechanisms are investigated using time-resolved photoluminescence and X-ray diffraction spectroscopy. 相似文献
988.
A series of metal coordination polymers, [Co2(NB)4(bpp)2(H2O)]·H2O ( 1 ), [Co2(e,e‐trans‐chdc)(e,a‐cis‐chdc)(bpp)2] ( 2 ), [Ni(e,e‐trans‐chdc)(bpp)(H2O)2] ( 3 ), [Ni2(PDA)2(bpp)2(H2O)3]·H2O ( 4 ), and [Ni‐(mBDC)(bpp)] ( 5 ) (NB = 3‐nitrobenzoate anion; bpp = 4,4′‐trimethylene dipyridine; chdc = cyclohexane‐1,4‐dicarboxylate anion; PDA = 1,4‐phenylenediacetate anion; mBDC = 1,3‐benzene dicarboxylate anion), were synthesized from metal ions and organic mixed‐ligands by hydrothermal reactions. The single crystal structure analysis revealed that 1, 3, and 4 were 2D sheets with bilayer (1 and 4) and 2‐fold interpenetrated layers (3), 2 is a 3D binodal (4,5)‐connected framework, and 5 is a 1D chains. The non‐covalent interactions of H‐bonds and π–π stacking caused this conformation of highly cross‐linked networks. Compounds 1‐5 were further characterized by thermal gravimetric analysis, powder X‐ray diffraction, UV‐vis, infrared, and PL spectroscopy. 相似文献
989.
GeO2 thin films were prepared by sol‐gel method on ITO/Glass substrate. The electrical and optical properties and the microstructures of these films were investigated with special emphasis on the effects of an annealing treatment in ambient air. The films were annealed at various temperatures from 500 °C to 700 °C. Structural analysis through X‐ray diffraction (XRD) and atomic force microscope (AFM) showed that surface structure and morphological characteristics were sensitive to the treatment conditions. The optical transmittance spectra of the GeO2/ITO/Glass were measured using a UV‐visible spectrophotometer. All films exhibited GeO2 (101) orientation perpendicular to the substrate surface where the grain size increased with increasing annealing temperature. The optical transmittance spectroscopy further revealed high transparency (over 70 %) in the wave range 400 – 800 nm of the visible region. At an annealing temperature level of 700 °C, the GeO2 films were found to possess a leakage current density of 1.31×10‐6A/cm2 at an electrical field of 20 kV/cm. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
990.
Chang S. Hsu 《光谱学快报》2013,46(9):439-447
The vibrational analysis of allyl mercaptan has vener been published. There are two internal rotors, the SH group and the CH2SH group, in the allyl mercaptan molecule. As in the case of propylene (1), the molecule has only one plane of symmetry (Cs point group) in its most symmetrical configuration (when the thiol group lies in the plane of the vinyl group). However, microwave studies have shown that it exhibits C1 symmetry (2). The infrared and Raman spectra of allyl mercaptan have been investigated in this study. The assignment of its fundamental modes has been made based on C1 symmetry of the molecule. 相似文献