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261.
Evagelos Gikas Fotini N. Bazoti Panagiotis Fanourgiakis Efstathia Perivolioti Andreas Roussidis Athanasios Skoutelis Anthony Tsarbopoulos 《Biomedical chromatography : BMC》2010,24(5):522-527
Daptomycin (DPT) is a lipopeptide antibiotic with potent bactericidal activity in vitro against Gram‐positive bacteria, which has attracted the attention of the scientific community due to its unique mechanism of action and due to the immediate need for new antibiotics in the era of multidrug resistance. In order to assess its pharmacokinetics in rabbits a new analytical method has been developed and validated using ultra performance liquid chromatography in conjugation with ultraviolet detection for the quantitation of the antibiotic in rabbit plasma, using the internal standard methodology. The separation was achieved employing a C18 column with gradient elution using 0.1% aq. trifluoroacetic acid and methanol. The total analysis time was 2.5 min. The sample pretreatment employed protein precipitation with acetonitrile–methanol mixture and centrifugation. The method was validated in terms of linearity, precision, accuracy, sensitivity, robustness, short‐term and freeze–thaw stability and was applied to the quantification of DPT in plasma samples obtained from rabbits treated with 25 mg kg?1 DPT. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
262.
Aqueous-phase exfoliation of graphite in the presence of polyvinylpyrrolidone for the production of water-soluble graphenes 总被引:1,自引:0,他引:1
Athanasios B. Bourlinos Vasilios Georgakilas Radek Zboril Theodore A. Steriotis Athanasios K. Stubos Christos Trapalis 《Solid State Communications》2009,149(47-48):2172-2176
Treatment of crystalline graphite fine powder with an aqueous solution of the harmless and versatile substance polyvinylpyrrolidone under sonication results in water-soluble, polymer-protected graphene single layers without oxidation or destruction of the sp2 character of the carbon core. The liquid-phase extraction of graphene monolayers was evidenced by TEM and AFM techniques, while their graphitic character was checked with Raman spectroscopy. Besides PVP, the water-soluble biopolymers albumin and sodic carboxymethylcellulose were also employed successfully in the aqueous-phase exfoliation of graphite, thereby supporting the generic character of the present method using a variety of suitable polymeric extractants. 相似文献
263.
Florent Berthelin Athanasios E. Tzavaras Alexis Vasseur 《Journal of statistical physics》2009,135(1):153-173
This article is devoted to the proof of the hydrodynamic limit for a discrete velocity Boltzmann equation before appearance
of shocks in the limit system.
Partially supported by the National Science Foundation Grants DMS-0607053, DMS-0555272 and DMS-0757227, and by the program
“Pythagoras” of the Greek Secretariat of Research. 相似文献
264.
Kottas Athanasios Gelfand Alan E. 《Methodology and Computing in Applied Probability》2001,3(4):427-442
In comparing two populations, sometimes a model incorporating a certain probability order is desired. In this setting, Bayesian modeling is attractive since a probability order restriction imposed a priori on the population distributions is retained a posteriori. Extending the work in Gelfand and Kottas (2001) for stochastic order specifications, we formulate modeling for distributions ordered in variability. We work with Dirichlet process mixtures resulting in a fully Bayesian semiparametric approach. The details for simulation-based model fitting and prior specification are provided. An example, based on two small subsets of time intervals between eruptions of the Old Faithful geyser, illustrates the methodology. 相似文献
265.
The sensor virus is a serious threat,as an attacker can simply send a single packet to compromise the entire sensor network.Epidemics become drastic with link additions among sensors when the small world phenomena occur.Two immunization strategies,uniform immunization and temporary immunization,are conducted on small worlds of tree-based wireless sensor networks to combat the sensor viruses.With the former strategy,the infection extends exponentially,although the immunization effectively reduces the contagion speed.With the latter strategy,recurrent contagion oscillations occur in the small world when the spatial-temporal dynamics of the epidemic are considered.The oscillations come from the small-world structure and the temporary immunization.Mathematical analyses on the small world of the Cayley tree are presented to reveal the epidemic dynamics with the two immunization strategies. 相似文献
266.
Natasa P. Kalogiouri Petros D. Mitsikaris Dimitris Klaoudatos Athanasios N. Papadopoulos Victoria F. Samanidou 《Molecules (Basel, Switzerland)》2021,26(18)
Reversed phase-high-pressure liquid chromatographic methodologies equipped with UV detector (RP-HPLC-UV) were developed for the determination of phenolic compounds and tocopherols in almonds. Nineteen samples of Texas almonds originating from USA and Greece were analyzed and 7 phenolic acids, 7 flavonoids, and tocopherols (−α, −β + γ) were determined. The analytical methodologies were validated and presented excellent linearity (r2 > 0.99), high recoveries over the range between 83.1 (syringic acid) to 95.5% (ferulic acid) for within-day assay (n = 6), and between 90.2 (diosmin) to 103.4% (rosmarinic acid) for between-day assay (n = 3 × 3), for phenolic compounds, and between 95.1 and 100.4% for within-day assay (n = 6), and between 93.2–96.2% for between-day assay (n = 3 × 3) for tocopherols. The analytes were further quantified, and the results were analyzed by principal component analysis (PCA), and agglomerative hierarchical clustering (AHC) to investigate potential differences between the bioactive content of almonds and the geographical origin. A decision tree (DT) was developed for the prediction of the geographical origin of almonds proposing a characteristic marker with a concentration threshold, proving to be a promising and reliable tool for the guarantee of the authenticity of the almonds. 相似文献
267.
Koutmos M Kalyvas H Sanakis Y Simopoulos A Coucouvanis D 《Journal of the American Chemical Society》2005,127(11):3706-3707
The systematic synthesis of heterometallic Ni/Fe/S and Cu/Fe/S clusters with a M8S6 core structure that resembles that of pentlandite minerals is described. The chemical properties and electronic structures of the new clusters have been investigated and are reported in this communication. 相似文献
268.
We derive regularity properties for the density of states in the Anderson model on a one-dimensional strip for potentials with singular continuous distributions. For example, if the characteristic function is infinitely differentiable with bounded derivatives and together with all its derivatives goes to zero at infinity, we show that the density of states is infinitely differentiable. 相似文献
269.
270.
In this paper the linear two-level problem is considered. The problem is reformulated to an equivalent quasiconcave minimization problem, via a reverse convex transformation. A branch and bound algorithm is developed which takes the specific structure into account and combines an outer approximation technique with a subdivision procedure. 相似文献