Papers by gilberto salazar
Journal of Petroleum Science and Engineering, 2007
This paper presents a theoretical analysis of the problem of cuttings transport for a two-region ... more This paper presents a theoretical analysis of the problem of cuttings transport for a two-region system composed of a fluid bed (ω-region) and a stationary bed of drill cuttings, which is considered as a porous medium (η-region) in the two-phase system. The ω-region is made up of a solid phase (σ-phase) dispersed in a continuos fluid phase (β-phase), while the η-region consists of a stationary solid phase (σ-phase) and a fluid phase (β-phase). The volume averaging method was applied in this study. Volumeaveraged transport equations were derived for both the fluid bed and the porous medium regions. These equations are based on the non-local form of the volume-averaged momentum transport equation that is valid within the bounded region. Outside this region, the non-local form reduces to the classic volume-averaged transport equation. From these equations, a one-equation model was obtained, and the constraints that the one-equation model must satisfy were applied. For estimating the averaged pressure drop and the averaged velocity, the one-equation model was solved numerically by using the finite-difference technique in the implicit scheme. Numerical results are in agreement with experimental data and theoretical results reported in the literature.
British Journal of Pharmacology, 2010
Background and purpose: This study establishes a pharmacokinetic/pharmacodynamic (PK/PD) model t... more Background and purpose: This study establishes a pharmacokinetic/pharmacodynamic (PK/PD) model to describe the time course and in vivo mechanisms of action of the antinociceptive effects of lumiracoxib, evaluated by the thermal hyperalgesia test in rats.Experimental approach: Female Wistar fasted rats were injected s.c. with saline or carrageenan in the right hind paw, followed by either 0, 1, 3, 10 or 30 mg·kg−1 of oral lumiracoxib at the time of carrageenan injection (experiment I), or 0, 10 or 30 mg·kg−1 oral lumiracoxib at 4 h after carrageenan injection (experiment II). Antihyperalgesic responses were measured as latency time (LT) to a thermal stimulus. PK/PD modelling of the antinociceptive response was performed using the population approach with NONMEM VI.Results: A two-compartment model described the plasma disposition. A first-order model, including lag time and decreased relative bioavailability as a function of the dose, described the absorption process. The response model was: LT=LT0/(1 +MED). LT0 is the baseline response, and MED represents the level of inflammatory mediators. The time course of MED was assumed to be equivalent to the predicted profile of COX-2 activity and was modelled according to an indirect response model with a time variant synthesis rate. Drug effects were described as a reversible inhibition of the COX-2 activity. The in vivo estimate of the dissociation equilibrium constant of the COX-2-lumiracoxib complex was 0.24 µg·mL−1.Conclusions: The model developed appropriately described the time course of pharmacological responses to lumiracoxib, in terms of its mechanism of action and pharmacokinetics.
... Daniel Ariano1,2 & Gilberto Salazar2 1Postgrado de Biología, Universidad de Costa Rica, S... more ... Daniel Ariano1,2 & Gilberto Salazar2 1Postgrado de Biología, Universidad de Costa Rica, San Pedro-San José, Costa Rica (darianosanchez@gmail ... This lends sup-port for the hypothesis proposed originally by Stuart (1954) that a Pacific subhumid corridor was the route by ...
El juego no lo hemos inventado los hombres; los cachorros de muchos mamíferos utilizan el juego p... more El juego no lo hemos inventado los hombres; los cachorros de muchos mamíferos utilizan el juego para desarrollar habilidades que les van a ser necesarias a lo largo de la vida. Comportamientos como la persecución, la lucha y la caza se perfeccionan en una simulación jovial, carente de peligro y dramatismo, que constituye una actividad necesaria y eficaz en el aprendizaje para la vida.
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Papers by gilberto salazar