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161.
Sandoval IT Davis RA Bugni TS Concepcion GP Harper MK Ireland CM 《Natural product research》2004,18(1):89-93
Bioassay-guided fractionation of two Philippine sponges of the genus Petrosia has resulted in the isolation of the novel natural product cribrostatin 7 (1) and the known compounds renierone (2) and O-demethylrenierone (3). The structures of these isoquinoline quinones were determined by interpretation of spectroscopic data. Compounds 1, 2 and 3 were cytotoxic against the HCT 116 human colon carcinoma cell line with IC50 values of 45, 24 and 34 microg/mL, respectively. 相似文献
162.
Rohan A DavisImelda T Sandoval Gisela P ConcepcionRosana Moreira da Rocha Chris M Ireland 《Tetrahedron》2003,59(16):2855-2859
Bioassay-guided fractionation of the MeOH extract from a Philippine didemnid ascidian resulted in the isolation of two new dimeric alkaloids, lissoclinotoxins E (1) and F (2). The polysulfide structures for compounds 1 and 2 were determined by interpretation of spectroscopic data and chemical degradation. Computational chemistry studies suggested that the N-alkyl chains about the tricyclic systems of lissoclinotoxins E and F had trans and cis orientations, respectively. Alkaloids 1 and 2 displayed IC50 values of 2.3 and 1.5 μg/mL, respectively, towards the PTEN-deficient human breast carcinoma cell line, MDA-MB-468. 相似文献
163.
164.
We consider an elastic plate governed by the Reissner–Mindlin?s model, i.e., whose equilibrium equations introduce a coupling between the vertical displacement and the rotation of the normal. This structure is made of a composite with a periodic arrangement of strongly heterogeneous materials and some characteristics of the heterogeneities are comparable to the size of the microstructures. We show that, when the size of the microstructures tends to zero, the limit homogeneous structure presents, for some wavelengths, a negative “mass density” tensor. This means that there exist intervals of frequencies – the band gaps – for which wave propagation is suppressed, or restricted to certain polarizations. 相似文献
165.
166.
A simple and efficient biomimetic synthesis of pyrrolo[1,2-a]indoles using a highly stereo- and regioselective [3 + 2] reaction cascade was developed and then further applied in the first total synthesis of flinderoles B and C, which proceeded in 17.2% yield over the longest linear sequence of 11 steps. 相似文献
167.
Amin Ghadi Ali-Reza Bahrampour Reza Farrahi-Moghaddam Majid Taraz 《Optics Communications》2008,281(9):2644-2650
The high degree of intensity values in microring resonators needs a careful treatment of nonlinear phenomena. Nonlinear effects are analyzed in coupling problem of ring-ring directional couplers. It has been observed that the nonlinearity affects the coupling device dramatically, and can be used as controlling techniques in such as coupled resonator optical waveguides. 相似文献
168.
The influence of disorder and stoichiometry-breaking point defects on the structural and magnetic properties of Sr2FeMoO6 is studied by electronic structure calculations within the spin-polarized GGA+U approach. 相似文献
169.
Michael Wilms Lesly V. Melendez Dr. Rohan J. Hudson Dr. Christopher R. Hall Samantha Prabath Ratnayake Prof. Dr. Trevor Smith Prof. Dr. Enrico Della Gaspera Prof. Dr. Gary Bryant Dr. Timothy U. Connell Prof. Dr. Daniel E. Gómez 《Angewandte Chemie (International ed. in English)》2023,62(24):e202303501
We report a new composite material consisting of silver nanoparticles decorated with three-dimensional molecular organic cages based on light-absorbing porphyrins. The porphyrin cages serve to both stabilize the particles and allow diffusion and trapping of small molecules close to the metallic surface. Combining these two photoactive components results in a Fano-resonant interaction between the porphyrin Soret band and the nanoparticle-localised surface-plasmon resonance. Time-resolved spectroscopy revealed the silver nanoparticles transfer up to 37 % of their excited-state energy to the stabilising layer of porphyrin cages. These unusual photophysics cause a 2-fold current increase in photoelectrochemical water-splitting measurements. The composite structure provides a compelling proof of concept for advanced photosensitiser systems with intrinsic porosity for photocatalytic and sensing applications. 相似文献