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101.
A novel bioanalytical method based on UHPLC‐HRMS/MS for the quantification of oleuropein in human serum. Application to a pharmacokinetic study 下载免费PDF全文
Nikolaos Lemonakis Vassilis Mougios Maria Halabalaki Alexios– Leandros Skaltsounis Evagelos Gikas 《Biomedical chromatography : BMC》2016,30(12):2016-2023
A highly sensitive, rapid and specific ultrahigh‐performance liquid chromatography, coupled to negative electrospray ionization high‐resolution tandem mass spectrometry, method was developed and validated in order to investigate the absorption of dietary oleuropein (OE) in human subjects. Serum samples were collected at predefined time points, after oral administration of an olive leaf extract enriched in OE (204.4 mg OE per capsule) to two subjects. Subsequently, samples were analyzed by the developed method after a simple solid‐phase extraction step. Chromatographic separation was operated with aqueous formic acid, 0.1% (v/v), and acetonitrile following a gradient program at a flow rate of 0.45 mL/min in an RP‐C18 (50 × 2.1 mm, 1.9 μm) column with a total run time of 2.7 min. The method was validated and successfully applied to the determination of OE in human serum, with the pharmacokinetic analysis of the data revealing a biphasic response. 相似文献
102.
Michael A. Terzidis Constantinos A. Tsoleridis Aristides Terzis Vassilis Psycharis 《Tetrahedron》2010,66(4):947-9014
The 1,4-zwitterion derived from 4,5-dimethylthiazole and acetylenedicarboxylates has been shown to react at low temperature readily with 3-formylchromones (chromone-3-carboxaldehydes) resulting, after an unusual rearrangement, in the facile synthesis of thiazolo[3,2-a]pyridine derivatives; in the case of electron-donating substituents in the chromone ring tetracyclic chromenothiazolopyridines are isolated as the main reaction products. However, at higher temperature after an unexpected 1,2-aroyl migration 8-formyl-5H-[1,3]thiazolo[3,2-a]pyridines are formed as a mixture of two rotamers. Structural assignments of the new compounds as well as complete assignment of 1H and 13C NMR signals were based on the analysis of their 1H and 13C NMR (1D and 2D), IR, MS and elemental analysis data. Plausible mechanisms are proposed. 相似文献
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104.
Sagnou M Benaki D Triantis C Tsotakos T Psycharis V Raptopoulou CP Pirmettis I Papadopoulos M Pelecanou M 《Inorganic chemistry》2011,50(4):1295-1303
The synthesis and characterization of "2 + 1" complexes of the [M(CO)(3)](+) (M = Re, (99m)Tc) core with the β-diketones acetylacetone (complexes 2, 8) and curcumin (complexes 5, 10 and 6, 11) as bidentate OO ligands, and imidazole or isocyanocyclohexane as monodentate ligands is reported. The complexes were synthesized by reacting the [NEt(4)](2)[Re(CO)(3)Br(3)] precursor with the β-diketone to generate the intermediate aqua complex fac-Re(CO)(3)(OO)(H(2)O) that was isolated and characterized, followed by replacement of the labile water by the monodentate ligand. All complexes were characterized by mass spectrometry, NMR and IR spectroscopies, and elemental analysis. In the case of complex 2, bearing imidazole as the monodentate ligand, X-ray analysis was possible. The chemistry was successfully transferred at (99m)Tc tracer level. The curcumin complexes 5 and 6, as well as their intermediate aqua complex 4, that bear potential for radiopharmaceutical applications due to the wide spectrum of pharmacological activity of curcumin, were successfully tested for selective staining of β-amyloid plaques of Alzheimer's disease. The fact that the complexes maintain the affinity of the mother compound curcumin for β-amyloid plaques prompts for further exploration of their chemistry and biological properties as radioimaging probes. 相似文献
105.
Vassili Kitsios Daniel Rodríguez Vassilis Theofilis Andrew Ooi Julio Soria 《Journal of computational physics》2009,228(19):7181-7196
A methodology based on spectral collocation numerical methods for global flow stability analysis of incompressible external flows is presented. A potential shortcoming of spectral methods, namely the handling of the complex geometries encountered in global stability analysis, has been dealt with successfully in past works by the development of spectral-element methods on unstructured meshes. The present contribution shows that a certain degree of regularity of the geometry may be exploited in order to build a global stability analysis approach based on a regular spectral rectangular grid in curvilinear coordinates and conformal mappings. The derivation of the stability linear operator in curvilinear coordinates is presented along with the discretisation method. Unlike common practice to the solution of the same problem, the matrix discretising the eigenvalue problem is formed and stored. Subspace iteration and massive parallelisation are used in order to recover a wide window of its leading Ritz system. The method is applied to two external flows, both of which are lifting bodies with separation occurring just downstream of the leading edge. Specifically the flow configurations are a NACA 0015 airfoil, and an ellipse of aspect ratio 8 chosen to closely approximate the geometry of the airfoil. Both flow configurations are at an angle of attack of 18° with a Reynolds number based on the chord length of 200. The results of the stability analysis for both geometries are presented and illustrate analogous features. 相似文献
106.
Mohamed Afif Mhand Hifi Vangelis Th. Paschos Vassilis Zissimopoulos 《The Journal of the Operational Research Society》1995,46(10):1260-1268
We solve approximately the minimum set covering problem by developing a new heuristic, which is essentially based on the flow algorithm originally developed by Ford and Fulkerson. We perform a comparative study of the performances (concerning solution qualities and execution times) of the flow algorithm as well as of the natural greedy heuristic for set covering originally studied by Johnson and Lovász. 相似文献
107.
Wei-Tzou Luh Vassilis Zafiropulos Paul D. Kleiber William C. Stwalley Shawn P. Heneghan 《Journal of Molecular Spectroscopy》1985,111(2):327-343
The gold vapor laser has been used to irradiate the alkali dimers Li2, Na2, K2, and Rb2. Significant fluorescence was found only from Na2 and K2. Six fluorescent series in the A1Σu+-X1Σg+ system of Na2 and three in the B1Πu-X1Σg+ system of K2 were assigned, respectively. New spectroscopic constants for the X1Σg+ state of 39K2 are derived, and new RKR potential energy curves for the X1Σg+ and B1Πu states of 39K2 are given. 相似文献
108.
109.
Polyzos I Tsigaridas G Fakis M Giannetas V Persephonis P Mikroyannidis J 《The journal of physical chemistry. B》2006,110(6):2593-2597
The current article presents the photobleaching properties of a group of pyrylium salts under ultrashort pulsed illumination. These pyrylium salts have the same basic chemical structure and differ only by a specific substituent. It is proven experimentally that two different mechanisms are simultaneously present to the photobleaching of all molecules studied (independently of their specific chemical structure). However, the particular parameters of each mechanism are influenced significantly by the substituent change. The experimental investigation of these parameters showed the presence of multiphoton interactions in the photobleaching of pyrylium salts depending essentially on the specific substituent. 相似文献