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131.
Angela LaBella Francesca Leonelli Ilse DeSalve LuisaM. Migneco Rinaldo MariniBettolo 《Helvetica chimica acta》2004,87(8):2120-2124
A new preparation and the isolation and spectroscopic characterization of 1,3,3‐trimethylbicyclo[2.2.2]octan‐2,6‐dione ( 3 ), a so far elusive key intermediate in the Liu–Ralitsch total synthesis of (+)‐norpatchoulenol ((+)‐ 1a ), is described. The preparation of 3 constitutes also a formal total synthesis of (±)‐iso‐norpatchoulenol ((±)‐ 1b ), since 3 is correlated to an intermediate in the Monti and co‐workers synthesis of (±)‐ 1b . 相似文献
132.
Graeme B Bolger Angela McCahill Stephen J Yarwood Michael R Steele Jim Warwicker Miles D Houslay 《BMC biochemistry》2002,3(1):24-11
Background
The cyclic AMP specific phosphodiesterase, PDE4D5 interacts with the β-propeller protein RACK1 to form a signaling scaffold complex in cells. Two-hybrid analysis of truncation and mutant constructs of the unique N-terminal region of the cAMP-specific phosphodiesterase, PDE4D5 were used to define a domain conferring interaction with the signaling scaffold protein, RACK1. 相似文献133.
Alberto Plaza Sonia Piacente Angela Perrone Arafa Hamed Cosimo Pizza Giuseppe Bifulco 《Tetrahedron》2004,60(52):12201-12209
Stemmosides C and D, two novel pregnane glycosides characterized by an unusual C-17 side chain were isolated from the pericarps of Solenostemma argel. In addition, stemmoside D displays an uncommon 14β proton configuration, apparently being the first pregnane isolated from plants known to have a 15 keto, cis CD ring junction. Their structures have been established by ESIMS and NMR experiments. The relative configuration of the molecules was determined using a strategy based on the simulation of 1H, 13C, and J coupling NMR parameters. DFT calculations of 1H and 13C chemical shifts, and of the 1H homonuclear spin–spin coupling constants were performed with the mPW1PW91 functional using the 6-31G(d,p) basis set on the fully optimized geometries of all the possible stereoisomers. 相似文献
134.
135.
Gaetano Corso Monica Gelzo Angela Chambery Valeria Severino Antimo Di Maro Filomena Schiano Lomoriello Oceania D'Apolito Antonio Dello Russo Patrizia Gargiulo Ciro Piccioli Paolo Arcari 《Journal of separation science》2012,35(21):2986-2993
Spectroscopic and MS techniques were used to characterize the pigments and the composition of polar and nonpolar binders of a stray wall painting fragment from Liternum (Italy) archaeological excavation. X‐ray fluorescence and diffraction analysis of the decorations indicated mainly the presence of calcite, quartz, hematite, cinnabar, and cuprorivaite. Infrared spectroscopy, GC coupled to flame‐ionization detector, and MS analysis of the polar and nonpolar components extracted from paint layers from three different color regions revealed the presence of free amino acids, sugars, and fatty acids. Interestingly, LC‐MS shotgun analysis of the red painting region showed the presence of αS1‐casein of buffalo origin. Compared to our previous results from Pompeii's wall paintings, even though the Liternum painting mixture contained also binders of animal origin, the data strongly suggest that in both cases a tempera painting technique was utilized. 相似文献
136.
137.
A collaborative study was conducted to compare a new enrichment procedure for the TECRA Salmonella Visual Immunoassay (TSVIA) with the reference method given in the U.S. Food and Drug Administration's Bacteriological Analytical Manual (7th Ed.). Three food types (milk powder, pepper, and soy flour) were analyzed in Australia and 3 food types (milk chocolate, dried egg, and raw turkey) were analyzed in the United States. Thirty-eight collaborators participated in the study. The TECRA method was evaluated using both Rappaport-Vassiliadis R10 (RV(R10)) and tetrathionate (TT) broths for selective enrichment. M broth cultures arising from each of the 2 selective enrichment broths were tested in the TSVIA using 2 individual wells, one for each selective broth, and a single well to test the pooled selective enrichment broths. The results for the pooled enrichment broths were reported elsewhere. This study presents the results for the use of single enrichment broths, i.e., RV(R10) only or TT only, with the TSVIA. No significant differences (p > 0.05) were observed for the pairwise comparison of the proportion of positive samples for either RV(R10) or TT used as a single enrichment broth for the TSVIA with that for the reference method. 相似文献
138.
High‐Potential Perfluorinated Phthalocyanine–Fullerene Dyads for Generation of High‐Energy Charge‐Separated States: Formation and Photoinduced Electron‐Transfer Studies 下载免费PDF全文
Dr. Sushanta K. Das Andrew Mahler Prof. Angela K. Wilson Prof. Dr. Francis D'Souza 《Chemphyschem》2014,15(12):2462-2472
High oxidation potential perfluorinated zinc phthalocyanines (ZnFnPcs) are synthesised and their spectroscopic, redox, and light‐induced electron‐transfer properties investigated systematically by forming donor–acceptor dyads through metal–ligand axial coordination of fullerene (C60) derivatives. Absorption and fluorescence spectral studies reveal efficient binding of the pyridine‐ (Py) and phenylimidazole‐functionalised fullerene (C60Im) derivatives to the zinc centre of the FnPcs. The determined binding constants, K, in o‐dichlorobenzene for the 1:1 complexes are in the order of 104 to 105 M ?1; nearly an order of magnitude higher than that observed for the dyad formed from zinc phthalocyanine (ZnPc) lacking fluorine substituents. The geometry and electronic structure of the dyads are determined by using the B3LYP/6‐31G* method. The HOMO and LUMO levels are located on the Pc and C60 entities, respectively; this suggests the formation of ZnFnPc.+–C60Im.? and ZnFnPc.+–C60Py.? (n=0, 8 or 16) intra‐supramolecular charge‐separated states during electron transfer. Electrochemical studies on the ZnPc–C60 dyads enable accurate determination of their oxidation and reduction potentials and the energy of the charge‐separated states. The energy of the charge‐separated state for dyads composed of ZnFnPc is higher than that of normal ZnPc–C60 dyads and reveals their significance in harvesting higher amounts of light energy. Evidence for charge separation in the dyads is secured from femtosecond transient absorption studies in nonpolar toluene. Kinetic evaluation of the cation and anion radical ion peaks reveals ultrafast charge separation and charge recombination in dyads composed of perfluorinated phthalocyanine and fullerene; this implies their significance in solar‐energy harvesting and optoelectronic device building applications. 相似文献
139.
A Diverse Assemblage of Indole-3-Acetic Acid Producing Bacteria Associate with Unicellular Green Algae 总被引:1,自引:0,他引:1
Christopher E. Bagwell Magdalena Piskorska Tanya Soule Angela Petelos Chris M. Yeager 《Applied biochemistry and biotechnology》2014,173(8):1977-1984
Microalgae have tremendous potential as a renewable feedstock for the production of liquid transportation fuels. In natural waters, the importance of physical associations and biochemical interactions between microalgae and bacteria is generally well appreciated, but the significance of these interactions to algal biofuels production have not been investigated. Here, we provide a preliminary report on the frequency of co-occurrence between indole-3-acetic acid (IAA)-producing bacteria and green algae in natural and engineered ecosystems. Growth experiments with unicellular algae, Chlorella and Scenedesmus, revealed IAA concentration-dependent responses in chlorophyll content and dry weight. Importantly, discrete concentrations of IAA resulted in cell culture synchronization, suggesting that biochemical priming of cellular metabolism could vastly improve the reliability of high density cultivation. Bacterial interactions may have an important influence on algal growth and development; thus, the preservation or engineered construction of the algal–bacterial assembly could serve as a control point for achieving low input, reliable production of algal biofuels. 相似文献
140.
Malva sylvestris L. extract suppresses desferrioxamine‐induced PGE2 and PGD2 release in differentiated U937 cells: the development and validation of an LC‐MS/MS method for prostaglandin quantification 下载免费PDF全文
Cleverson Antonio Ferreira Martins Almeriane Maria Weffort‐Santos João Cleverson Gasparetto Angela Cristina Leal Badaró Trindade Michel Fleith Otuki Roberto Pontarolo 《Biomedical chromatography : BMC》2014,28(7):986-993
Malva sylvestris is a species used worldwide as an alternative to anti‐inflammatory therapies; however, its mechanism of action remains unknown. In this paper, the anti‐inflammatory effects of M. sylvestris alcoholic extracts were evaluated by measuring the pro‐inflammatory mediators PGE2 and PGD2 in desferrioxamine‐stimulated phorbol 12‐myristate 13‐acetate‐differentiated U937 cells. An HPLC‐DAD fingerprint of the M. sylvestris extract was performed and caffeic acid, ferulic acid and scopoletin were identified and quantified. An HPLC‐MS/MS method was developed and validated to separate and measure the prostaglandins. The lower limits of detection (~0.5 ng/mL for PGE2 and PGD2) and quantification (1.0 ng/mL for PGE2 and PGD2) indicated that the method is highly sensitive. The calibration curves showed excellent coefficients of correlation (r > 0.99) over the range of 1.0–500.0 ng/mL, and at different levels, the accuracy ranged from 96.4 to 106.4% with an RSD < 10.0% for the precision study. This method was successfully applied using U937‐d cells. A significant dose‐dependent reduction of PGE2 and PGD2 levels occurred using 10 µg/mL (10.74 ± 2.86 and 9.60 ± 6.89%) and 50 µg/mL of extract (48.37 ± 3.24 and 53.06 ± 6.15%), suggesting that the anti‐inflammatory mechanisms evoked by M. sylvestris may be related to modulation of these mediators. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献