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51.
Edwards EL Rodrigues JA Ferreira J Goodall DM Rauter AP Justino J Thomas-Oates J 《Electrophoresis》2006,27(11):2164-2170
Genista tenera is endemic to the Portuguese island of Madeira, where an infusion of the aerial parts of the plant is used in folk medicine as an antidiabetic agent. Consequently the medicinal properties of the secondary metabolites of this plant have been the subject of an ongoing study. A recently reported LC-MS method using a 100 min separation allowed identification of five flavonoid components in an extract of the aerial parts of this plant. In order to obtain additional information on the range and complexity of the plant's secondary metabolite components a CE-MS method has been developed and applied for the analysis of an extract of G. tenera. Twenty-six different components are distinguished in an analysis time of only 10 min. Results demonstrate that CE-MS/MS rapidly generates data complementary to those obtainable by LC-MS/MS and is particularly suited to the analysis of plant metabolites where concentration is not limiting. 相似文献
52.
Goossens JF Mahieu C Dias N Bailly C Principe P Bonte JP Lansiaux A Vaccher C Foulon C 《Electrophoresis》2006,27(23):4717-4729
EKC methods for the enantiomeric resolution of homocamptothecin derivatives, potent anticancer agents targeting DNA topoisomerase I selected for clinical trials, were developed using highly sulfated beta-CD as chiral selectors at acidic pH. Optimal electrophoretic conditions, with migration times under 15 min, were as follows: for the neutral homocamptothecin analog 1, a BGE of 75 mM phosphate buffer pH 2.5 (H(3)PO(4) + triethanolamine)/ACN - 95/5 v/v, with 7.5% w/v highly S-beta-CD, an applied field of 0.2 kV/cm and a fused capillary temperature control of 30 +/- 0.1 degrees C (typical current approximately 175 microA); for the cationic homocamptothecin 2, a BGE of 25 mM phosphate buffer pH 2.5 (H(3)PO(4) + TEA)/ACN - 90/10 v/v, with 2.5% w/v highly S-beta-CD, an applied field of 0.15 kV/cm and a fused capillary temperature control of 25 +/- 0.1 degrees C (typical current approximately 45 muA), and both are validated. The best results in terms of LOQ were obtained by EC with fluorescence detection: 10 ng/mL and 20 ng/mL for 1 and 2, respectively (LOQ divided by 150 for 1 and 5 for 2 with respect to UV), thus making this method particularly convenient for enantiomeric purity determination of galenic forms. UV detection appears to be an alternative to fluorescence for the analysis of the main component either for the control of galenic forms or for therapeutic adaptation. Moreover, this method exhibits better performances than HPLC. 相似文献
53.
Microparticles are phospholipid vesicles shed mostly in biological fluids, such as blood or urine, by various types of cells, such as red blood cells (RBCs), platelets, lymphocytes, endothelial cells. These microparticles contain a subset of the proteome of their parent cell, and their ready availability in biological fluid has raised strong interest in their study, as they might be markers of cell damage. However, their small size as well as their particular physico-chemical properties makes them hard to detect, size, count and study by proteome analysis. In this review, we report the pre-analytical and methodological caveats that we have faced in our own research about red blood cell microparticles in the context of transfusion science, as well as examples from the literature on the proteomics of various kinds of microparticles. 相似文献
54.
Paulo J. Amorim Madeira Nuno M. Xavier Amélia P. Rauter M. Helena Florêncio 《Journal of mass spectrometry : JMS》2010,45(10):1167-1178
Sugars that incorporate the unsaturated carbonyl motif have become important synthetic targets not only as a result of their potential biological properties but also as precursors in the synthesis of many bioactive products. Moreover, little is known about the influence of the γ‐lactone moiety in the fragmentation pattern of furanose rings. Therefore, two α,β‐unsaturated γ‐lactones (butenolides) and two β‐hydroxy γ‐lactones, C? C linked to a furanose ring were studied using electrospray ionization FTICR mass spectrometry. The behaviour of the protonated and sodiated forms of the compounds under study has been compared considering their structural features. Fragmentation mechanisms were established and ion structures were proposed taking into account the MS2 and MS3 experiments, accurate mass measurements and semi‐empirical calculations. These inexpensive methods proved to be a valuable resource for proposing protonation sites and for the establishment of fragmentation pathways. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
55.
Emission lines varie in intensity on a nine orders range of magnitude depending on. 相似文献
56.
We consider the algebras Λ which satisfy the property that for each indecomposable module X, either its projective dimension pdΛ
X is at most one or its injective dimension idΛ
X is at most one. This clearly generalizes the so-called quasitilted algebras introduced by Happel–Reiten–Smal?. We show that
some of the niciest features for this latter class of algebras can be generalized to the case we are considering, in particular
the existence of a trisection in its module category.
Received: 26 August 1998 相似文献
57.
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59.
Barea E Batlle X Bourges P Corma A Fornés V Labarta A Puntes VF 《Journal of the American Chemical Society》2005,127(51):18026-18030
Subnanometric cobalt metallic particles, with an average size of 0.8 nm and an estimated number of 50 atoms, have been stabilized in the confined spaces within the nanopores of crystalline molecular sieves. Remarkably, these clusters show a rapid vanishing of the magnetization as the temperature is increased from 10 to 20 K because of the ferromagnetic-paramagnetic transition together with thermal fluctuations of the remaining moment. This dramatic reduction of the transition temperature is due to strong finite size effects. Such behavior, predicted for very small metallic particles, was never observed before due to the inherent difficulty in achieving subnanometric stable metallic particles. 相似文献
60.
Ryckebusch A Gilleron P Millet R Houssin R Lemoine A Pommery N Grellier P Sergheraert C Hénichart JP 《Chemical & pharmaceutical bulletin》2005,53(10):1324-1326
Protein farnesyltransferase of Plasmodium falciparum is a potential target in the treatment of malaria for which increased drug resistance is observed. The design, synthesis and evaluation of a series of N-(4-piperidinyl)benzamides is reported. The most potent compounds showed in vitro activity against the parasite at submicromolar concentrations. 相似文献