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Söhretoğlu D Sakar MK Sabuncuoğlu SA Ozgüneş H Duman H Sterner O 《Natural product research》2012,26(13):1261-1264
Chromatographic studies on the EtOAc soluble portion of the MeOH extract of Geranium lasiopus led to the isolation of eight flavonoids (kaempferol (1), quercetin (2), quercetin 3-O-β-glucopyranoside (3), quercetin 3-O-β-galactopyranoside (4), kaempferol 3-O-α-rhamnopyranosyl-(1?→?6)-β-glucopyranoside (5), quercetin 3-O-α-rhamnopyranosyl-(1?→?6)-β-glucopyranoside (6), kaempferol 3-O-α-rhamnopyranosyl-(1?→?2)-β-glucopyranoside (7) and quercetin 3-O-α-rhamnopyranosyl-(1?→?2)-β-glucopyranoside (8)), two simple phenolic compounds (gallic acid (9) and its methyl ester (10)) and a hydrolysable tannin (pusilagin (11)). The structures of the compounds were elucidated by 1- and 2-dimensional NMR techniques ((1)H, (13)C, COSY, HMBC, HMQC) and ESI-TOF-MS spectrometry. Inhibitory effects on H(2)O(2)-induced lipid peroxidation in human red blood cells of the different extracts of G. lasiopus, as well as isolated compounds, were investigated. All tested compounds showed comparable or higher activity than that of ascorbic acid and trolox. 相似文献
53.
Korolev A Victorova E Ibragimov T Kanatyeva A Kurganov A 《Journal of separation science》2012,35(8):957-963
Monolithic capillary columns based on divinylbenzene were synthesized using different alcanols as porogens. Prepared columns were tested in separation of polystyrene standards according to their molar mass (MM) and were characterized by corresponding calibration graphs. It was demonstrated that a decrease of alcanol chain length from dodecanol to octanol resulted in a decrease of column permeability and in an improved column ability to separate polystyrene standards. In contrast, removing a good solvent from porogen mixture results in an increase of column permeability and in a decrease of column performance toward polystyrene standards. Optimized synthetic conditions included porogen composed of nonanol and toluene or mesytilene, and the column prepared with this porogen was capable of separating a mixture of 14 polystyrene standards with MM ranged from several millions to oligomers. 相似文献
54.
K Ogura M Nishiuchi AS Pirozhkov T Tanimoto A Sagisaka TZh Esirkepov M Kando T Shizuma T Hayakawa H Kiriyama T Shimomura S Kondo S Kanazawa Y Nakai H Sasao F Sasao Y Fukuda H Sakaki M Kanasaki A Yogo SV Bulanov PR Bolton K Kondo 《Optics letters》2012,37(14):2868-2870
Using a high-contrast (10(10):1) and high-intensity (10(21) W/cm(2)) laser pulse with the duration of 40 fs from an optical parametric chirped-pulse amplification/Ti:sapphire laser, a 40 MeV proton bunch is obtained, which is a record for laser pulse with energy less than 10 J. The efficiency for generation of protons with kinetic energy above 15 MeV is 0.1%. 相似文献
55.
The measurement of the two-mode squeezed vacuum generated in an optical parametric amplifier (OPA) was performed with photon number resolving multipixel photon counters (MPPCs). Implementation of the MPPCs allows for the observation of noise reduction in a broad dynamic range of the OPA gain, which is inaccessible with standard single photon avalanche photodetectors. 相似文献
56.
Constantin Romanescu Timur R. Galeev Wei‐Li Li Alexander I. Boldyrev Lai‐Sheng Wang 《ChemInform》2012,43(2):no-no
Co@B‐8, Ru@B‐9, Co@B8, and Ru@B9 clusters are characterized by photoelectron spectroscopy and DFT calculations. 相似文献
57.
The phenomenon of "overlapping resonances interference-induced transparency" (ORIT) is introduced and studied in detail for the S(0) → S(2)∕S(1) photoexcitation of cold pyrazine (C(4)H(4)N(2)). In ORIT, a molecule becomes transparent at specific wavelengths due to interferences between envelopes of spectral lines displaying overlapping resonances. An example is the S(2)???S(1) internal conversion in pyrazine where destructive interference between overlapping resonances causes the S(0) → S(2)∕S(1) light absorption to disappear at certain wavelengths. ORIT may be of practical importance in multi-component mixtures where it would allow for the selective excitation of some molecules in preference to others. Interference-induced cross section enhancement is also shown. 相似文献
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Barkovskii Savelii V. Ulitko Maria V. Barkov Alexey Yu. Kochnev Ivan А. Zimnitskiy Nikolay S. Korotaev Vladislav Yu. Sosnovskikh Vyacheslav Ya. Stepanyuk Roman А. Madzhidov Timur I. 《Chemistry of Heterocyclic Compounds》2022,58(8-9):462-472
Chemistry of Heterocyclic Compounds - A method for a regio- and stereoselective synthesis of N-unsubstituted... 相似文献