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J Largo

Publications and source records attributed to J Largo.

7 recordsLinked to original sources
PubMed2006

Thermodynamic properties of van der Waals fluids from Monte Carlo simulations and perturbative Monte Carlo theory.

Computer simulations have been performed for fluids with van der Waals potential, that is, hard spheres with attractive inverse power tails, to determine the equation of state and the excess energy. On the other hand, the first- and second-order perturbative contributions to the energy and the zero- and first-order perturbative contributions to the compressibility factor have been determined too from Monte Carlo simulations performed on the reference hard-sphere system. The aim was to test the reliability of this "exact" perturbation theory. It has been found that the results obtained from the Monte Carlo perturbation theory for these two thermodynamic properties agree well with the direct Monte Carlo simulations. Moreover, it has been found that results from the Barker-Henderson [J. Chem. Phys. 47, 2856 (1967)] perturbation theory are in good agreement with those from the exact perturbation theory.

Journal Article↗
PubMed2005

Pair correlation function of short-ranged square-well fluids.

We have performed extensive Monte Carlo simulations in the canonical (NVT) ensemble of the pair correlation function for square-well fluids with well widths lambda-1 ranging from 0.1 to 1.0, in units of the diameter sigma of the particles. For each one of these widths, several densities rho and temperatures T in the ranges 0.1< or =rhosigma(3)< or =0.8 and T(c)(lambda) less or approximately T less or approximately 3T(c)(lambda), where T(c)(lambda) is the critical temperature, have been considered. The simulation data are used to examine the performance of two analytical theories in predicting the structure of these fluids: the perturbation theory proposed by Tang and Lu [Y. Tang and B. C.-Y. Lu, J. Chem. Phys. 100, 3079 (1994); 100, 6665 (1994)] and the nonperturbative model proposed by two of us [S. B. Yuste and A. Santos, J. Chem. Phys. 101 2355 (1994)]. It is observed that both theories complement each other, as the latter theory works well for short ranges and/or moderate densities, while the former theory works for long ranges and high densities.

Journal Article↗
PubMed2003

Generalized van der Waals theory for the thermodynamic properties of square-well fluids.

A theory previously developed for the coordination number of square-well fluids is used within the context of a generalized van der Waals theory to obtain the compressibility factor and the internal energy of these fluids. Results are compared with computer simulations for several densities, temperatures, and potential widths, which are also reported.

Journal Article↗
PubMed2000

[Evaluation of 2 tuberculosis chemoprophylaxis regimens in patients infected with human immunodeficiency virus. The GECMEI Group].

OBJECTIVE: To assess the compliance, tolerance and efficacy of a short chemoprophylaxis regimen (IR) for tuberculosis using isoniazid (INH) plus rifampin (RIF) during 3 months versus a standard regimen (I) of isoniazid during 12 months in HIV positive patients. MATERIAL AND METHODS: Prospective, comparative, randomized and open clinical trial in four general hospitals and one prison hospital of Castilla-La Mancha. Prophylaxis was administered to PPD-positive patients and to anergic patients according to the CDC recommendations (1991). Patients were randomized in two treatment groups: regimen IR, isoniazid 300 mg daily and rifampin 600 mg daily; regimen I, isoniazid 300 mg during 12 months. RESULTS: 133 patients were included, 64 to regimen I and 69 to regimen IR. Regimen IR had a better tolerance with a 28% of adverse effects versus 55% in regimen I. Hepatotoxicity was more frequent in regimen I with a RR = 2.2 (CI 95% 1.23-4.01). Severe hepatotoxicity leading to treatment withdrawal was related to drug administration time and was more frequent in the 12 months regimen group. Short regimen showed a better compliance, without significant differences. Tuberculosis incidence rate was a 4.23 cases/100 persons--year for regimen I and 2.08 in regimen IR, with a relative risk for developing tuberculosis with regimen IR group of 0.51 (CI 95% 0.09-2.8) versus regimen I group, without statistical significance. Prison stay was associated to a significant risk for tuberculosis, regardless of both regimens (RR = 9.2 CI 95%, 1.06-80.2). CONCLUSIONS: In HIV-infected patients with PPD(+) or anergic, regimen with IR is at least as effective as regimen I for preventing the development of tuberculous disease, and has less adverse effects.

AIDS-Related Opportunistic Infections↗
PubMed1995

Doxycycline-rifampin versus doxycycline-streptomycin in treatment of human brucellosis due to Brucella melitensis. The GECMEI Group. Grupo de Estudio de Castilla-la Mancha de Enfermedades Infecciosas.

Brucellosis is a common zoonosis in many parts of the world; the best regimen for the treatment of brucellosis has not been clearly determined. We have carried out a multicenter, open, controlled trial in five general hospitals in Spain to compare the efficacy and safety of doxycycline and rifampin (DR) versus doxycycline and streptomycin (DS) for the treatment of human brucellosis. The study included 194 ambulatory or hospitalized patients with acute brucellosis, without endocarditis or neurobrucellosis. The diagnostic criterion was isolation of Brucella species from blood or other tissues (n = 120) or a standard tube agglutination titer of 1/160 or more for anti-Brucella antibodies with compatible clinical findings (n = 74). Patients were randomly assigned to receive either 100 mg of doxycycline twice daily plus rifampin, 900 mg/day, in a single morning dose for 45 days (DR group) or the same dose of doxycycline for 45 days plus streptomycin, 1 g/day, intramuscularly for 14 days (DS group). A lack of therapeutic efficacy developed in 8 of the 100 patients in the DR group (8%) and in 2 of the 94 patients in the DS group (2%)(P = 0.10). Relapses occurred in 16 of the 100 patients in the DR group (16%) but in only 5 of the 94 patients in the DS group (5.3%) (P = 0.02). When relapse was considered in combination with initial lack of efficacy, 26 patients in the DR group (24%) and 7 patients in the DS group (7.45%) failed to respond to therapy (P = 0.0016). In general, therapy was well tolerated and only four patients (4%) in the DR group and two (2%) in the DS group had episodes of adverse effects necessitating discontinuation of treatment (P> 0.2). We conclude that a doxycycline-and-rifampin regimen is less effective than the doxycycline-and-streptomycin regimen in patients with acute brucellosis.

Adolescent↗