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101.
Fractionation of methanol extracts of the fruit bodies of two inedible mushrooms Hydnellum suaveolens and Hydnellum geogerirum (Thelephoraceae) resulted in isolation of two new p-terphenyl derivatives named hydnellins A and B and sarcodonin delta possessing N-oxide. Their structures were determined by 2D NMR, IR, UV spectroscopy, and chemical reaction. These terphenyls showed moderate antioxidant activity. 相似文献
102.
Yamada M Wakahara T Lian Y Tsuchiya T Akasaka T Waelchli M Mizorogi N Nagase S Kadish KM 《Journal of the American Chemical Society》2006,128(5):1400-1401
The mapping of bond connectivity in the carbon cage of [Ce@C82]- and full assignment of the NMR lines were successfully achieved by means of 2D INADEQUATE NMR measurement. Paramagnetic NMR analysis shows that the Ce atom in [Ce@C82]- is located at an off-centered position adjacent to a hexagonal ring along the C2 axis of the C2v-C82 cage. 相似文献
103.
Xu J Hasegawa M Harada K Kobayashi H Nagai H Namikoshi M 《Chemical & pharmaceutical bulletin》2006,54(6):852-854
Four new tetramic acid derivatives, named melophlins P, Q, R, and S (1-4), were isolated from two marine sponges of the genus Melophlus collected at Palau, together with seven known melophlins A, D, E, G, H, I, and O. The structures of the new compounds were elucidated on the basis of their spectral data. The absolute stereochemistries at the tetramic acid moieties of the new compounds were determined as 1 : 1 mixtures (racemic) by ESI-LC/MS analysis of derivatives obtained by oxidation and hydrolysis of the respective parent compounds. Melophlins P-S (1-4) showed cytotoxicity against the murine leukemia cell line L1210 with IC(50) values of 20.0, 10.5, 0.85, and 5.13 muM, respectively. 相似文献
104.
Moucun Yuan Michio Namikoshi Akira Otsuki Mariyo F. Watanabe Kenneth L. Rinehart 《Journal of the American Society for Mass Spectrometry》1999,10(11):1138-1151
Electrospray ionization mass spectrometry was used to develop a rapid, sensitive, and accurate method for determination and identification of hepatotoxic microcystins, cyanobacterial cyclic heptapeptides. To optimize the electrospray ionization conditions, factors affecting charge state distribution, such as amino acid components of sample, proton affinity of the additives, and additive concentration, were investigated in detail and a method for controlling charge states was developed to provide molecular-related ions for assignment of molecular weight and reasonably abundant precursor ions for MS/MS analysis. A procedure for identification of microcystins consisting of known amino acids was proposed: for microcystins giving abundant [M + 2H]2+ ions, the addition of nitrogen-containing bases to the aqueous sample solution is effective to obtain an increased intensity of [M + H]+ ions, whereas the addition of Lewis acids containing nitrogen can produce increased abundances of [M + 2H]2+ ions for microcystins giving weak [M + 2H]2+ ions. Microcystins possessing no arginine residue always give sodium adduct ions [M + Na]+ as the base peak, and these are difficult to fragment via low energy collision-induced dissociation to yield structurally informative products; the addition of oxalic acid increases [M + H]+ ion abundances, and these fragment readily. 相似文献
105.
106.
107.
Akane Sato Mizuho Okada Kazuya Saito Michio Sorai 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(5):564-565
In the crystal structure of the title charge‐transfer complex, namely trans‐stilbene–2,2′‐(2,3,5,6‐tetrafluorobenzene‐1,4‐diylidene)propanedinitrile (1/1) (trans‐STB–TCNQF4), C14H12·C12F4N4, the planar STB and TCNQF4 molecules are stacked alternately. The structure is not isostructural with that of STB–TCNQ. No anomaly was found in the displacement parameters of any atoms, while the bond length of the central C=C moiety was shorter than the corresponding bond in ethylene. This suggests that the central C=C moiety of the STB molecule vibrates with a large amplitude, similar to the case in free STB and STB–TCNQ. 相似文献
108.
Fusion of the eight vertex SOS model 总被引:4,自引:0,他引:4
Etsuro Date Michio Jimbo Tetsuji Miwa Masato Okado 《Letters in Mathematical Physics》1986,12(3):209-215
A higher spin analogue is presented of the eight vertex-SOS correspondence in the sense of Andrews-Baxter-Forrester. The resulting hierarchy of solvable models contain the hard hexagon model and its recent multi-state generalizations. 相似文献
109.
Epitaxial Sr(VxCryTi1−x−y)O3 (0≤x+y≤0.05) ternary composition spreads were grown on two different single crystal substrates, LaAlO3 and Nb-doped SrTiO3, by use of combinatorial laser molecular beam epitaxy with a specially patterned slide masking plate. The photocatalytic activity on the composition spreads was evaluated by the photo-reduction of Ag+ in an AgNO3 aqueous solution to deposit Ag metal on the spreads. The V-doping effect was found to depend greatly on the substrate: the photodeposition of Ag was much enhanced in the composition region of SrV0.05Ti0.95O3 only on the Nb-doped SrTiO3, but not on the LaAlO3 and non-doped SrTiO3. 相似文献
110.