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991.
992.
Sun CY Qin C Wang XL Yang GS Shao KZ Lan YQ Su ZM Huang P Wang CG Wang EB 《Dalton transactions (Cambridge, England : 2003)》2012,41(23):6906-6909
Zeolitic Imidazolate Framework-8 (ZIF-8), for the first time for ZIFs, exhibits a remarkable capacity for the anticancer drug 5-fluorouracil (5-FU), around 660 mg of 5-FU/g of ZIF-8, and presents a pH-triggered controlled drug release property. These prove ZIF-8 to be a valuable candidate for delivery of anticancer agents and reveal its potential applications in the treatment of cancer. 相似文献
993.
Huang P Qin C Wang XL Sun CY Xing Y Wang HN Shao KZ Su ZM 《Dalton transactions (Cambridge, England : 2003)》2012,41(20):6075-6077
A new organic-inorganic hybrid, [Cu(en)(2)](3){[Cu(en)(2)][H(6)SiNb(18)O(54)]}·22H(2)O (1, en = ethylenediamine) containing the crescent-shaped polyoxoanion [H(6)SiNb(18)O(54)](8-) and copper-organic cations has been successfully synthesized, and elemental analyses, IR spectra, thermogravimetric analyses and single-crystal X-ray diffraction were investigated. 相似文献
994.
Zhu C Shao R Reddy RA Chen D Shen Y Gong T Glaser MA Korblova E Rudquist P Maclennan JE Walba DM Clark NA 《Journal of the American Chemical Society》2012,134(23):9681-9687
We report a bent-core liquid crystal (LC) compound exhibiting two fluid smectic phases in which two-dimensional, polar, orthorhombic layers order into three-dimensional ferroelectric states. The lower-temperature phase has a uniform polarization field which responds in an analog fashion to applied electric field. The higher-temperature phase is a new smectic state with periodic undulation of the polarization, structurally modulated layers, and a bistable response to applied electric field which originates in the periodically splay-modulated bulk of the LC rather than by surface stabilization at the cell boundaries. 相似文献
995.
Two-photon fluorescence microscopy (TPFM) provides key advantages over conventional fluorescence imaging techniques, namely, increased penetration depth, lower tissue autofluorescence and self-absorption, and reduced photodamage and photobleaching and therefore is particularly useful for imaging deep tissues and animals. Enzyme-detecting, small molecule probes provide powerful alternatives over conventional fluorescent protein (FP)-based methods in bioimaging, primarily due to their favorable photophysical properties, cell permeability, and chemical tractability. In this article, we report the first fluorogenic, small molecule reporter system (Y2/Y1) capable of imaging endogenous phosphatase activities in both live mammalian cells and Drosophila brains. The one- and two-photon excited photophysical properties of the system were thoroughly investigated, thus confirming the system was indeed a suitable Turn-ON fluorescence pair for TPFM. To our knowledge, this is the first enzyme reporting two-photon fluorescence bioimaging system which was designed exclusively from a centrosymmetric dye possessing desirable two-photon properties. By conjugation of our reporter system to different cell-penetrating peptides (CPPs), we were able to achieve organelle- and tumor cell-specific imaging of phosphatase activities with good spatial and temporal resolution. The diffusion problem typically associated with most small molecule imaging probes was effectively abrogated. We further demonstrated this novel two-photon system could be used for imaging endogenous phosphatase activities in Drosophila brains with a detection depth of >100 μm. 相似文献
996.
Wanhua Wu Shaomin Ji Wenting Wu Jingyin Shao Dr. Huimin Guo Prof. Tony D. James Prof. Jianzhang Zhao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(16):4953-4964
RuII–bis‐pyridine complexes typically absorb below 450 nm in the UV spectrum and their molar extinction coefficients are only moderate (ε<16 000 M ?1 cm?1). Thus, RuII–polyimine complexes that show intense visible‐light absorptions are of great interest. However, no effective light‐harvesting ruthenium(II)/organic chromophore arrays have been reported. Herein, we report the first visible‐light‐harvesting RuII–coumarin arrays, which absorb at 475 nm (ε up to 63 300 M ?1 cm?1, 4‐fold higher than typical RuII–polyimine complexes). The donor excited state in these arrays is efficiently converted into an acceptor excited state (i.e., efficient energy‐transfer) without losses in the phosphorescence quantum yield of the acceptor. Based on steady‐state and time‐resolved spectroscopy and DFT calculations, we proposed a general rule for the design of RuII–polypyridine–chromophore light‐harvesting arrays, which states that the 1IL energy level of the ligand must be close to the respective energy level of the metal‐to‐ligand charge‐transfer (M LCT) states. Lower energy levels of 1IL/3IL than the corresponding 1M LCT/3M LCT states frustrate the cascade energy‐transfer process and, as a result, the harvested light energy cannot be efficiently transferred to the acceptor. We have also demonstrated that the light‐harvesting effect can be used to improve the upconversion quantum yield to 15.2 % (with 9,10‐diphenylanthracene as a triplet‐acceptor/annihilator), compared to the parent complex without the coumarin subunit, which showed an upconversion quantum yield of only 0.95 %. 相似文献
997.
Peng Shao Xiao-Yu Kuang Li-Ping Ding Ming-Min Zhong Zhen-hua Wang 《Physica B: Condensed Matter》2012,407(21):4379-4386
Equilibrium geometric structures, stabilities, and electronic properties of SinCu2 (n=1–8) clusters and pure silicon Sin (n=3–10) clusters are investigated systematically by exchange-correlation density functional (B3LYP). The optimized geometries show that the most stable isomers have 3D structure for n=2, 4–8, and Cu-substituted Sin+2 clusters is dominating growth pattern for the SinCu2 clusters. The calculated averaged binding energies, fragmentation energies, second-order difference of energies, and the HOMO–LUMO gaps show that Si2Cu2 and Si5Cu2 clusters have enhanced relative stabilities and chemical stability than their neighboring clusters. Electronic properties of SinCu2 (n=1–8) clusters are studied by calculating the natural population analysis and electrostatic potential, where the results show that the two copper atoms always possess positive charge and positive potential surround them. In addition, the VIP, VEA and the chemical hardness (η) are also analyzed and compared. 相似文献
998.
E. G. Fu Y. Q. Wang G. F. Zou J. Xiong M. J. Zhuo Q. M. Wei J. K. Baldwin Q. X. Jia L. Shao A. Misra M. Nastasi 《Applied Physics A: Materials Science & Processing》2012,108(1):121-126
We studied the effect of irradiation on small angle grain boundaries in mosaic structured Cu thin films. The films showed a decrease in mosaic spread via a narrowing of the full width at half maximum in XRD rocking curves and a smaller minimum yield of RBS channeling after irradiation. These data indicate the irradiation decreased the misorientation angles between mosaic blocks separated by small angle grain boundaries. Mechanisms involving interactions between grain boundary dislocations and irradiation induced defects are discussed. 相似文献
999.
We study the spatial distribution of electron spin polarization for a gate-controlled T-shaped channel on the surface of a three-dimensional topological insulator (3D TI). We demonstrate that an energy gap depending on channel geometry parameters is definitely opened due to the spatial confinement. Spin surface locking in momentum space for a uniform wide channel with Hamiltonian linearity in the wavevector is still kept, but it is broken with Hamiltonian nonlinearity in the wavevector, like that for two-dimensional surface states widely studied in the literature. However, the spin surface locking for a T-shaped channel is broken even with Hamiltonian linearity in the wavevector. Interestingly, the magnitude and direction of the in-plane spin polarization are spatially dependent in all regions due to the breaking of translational symmetry of the T-shaped channel system. These interesting findings for an electrically controlled nanostructure based on the 3D TI surface may be testable with the present experimental technique, and may provide further understanding the nature of 3D TI surface states. 相似文献
1000.
We report on the first-principles calculations of bandgap modulation in armchair MoS(2) nanoribbon (AMoS(2)NR) by transverse and perpendicular electric fields respectively. In the monolayer AMoS(2)NR case, it is shown that the bandgap can be significantly reduced and be closed by transverse field, whereas the bandgap modulation is absent under perpendicular field. The critical strength of transverse field for gap closure decreases as ribbon width increases. In the multilayer AMoS(2)NR case, in contrast, it is shown that the bandgap can be effectively reduced by both transverse and perpendicular fields. Nevertheless, it seems that the two fields exhibit different modulation effects on the gap. The critical strength of perpendicular field for gap closure decreases with increasing number of layers, while the critical strength of transverse field is almost independent of it. 相似文献