Methanol-enhanced degradation of carbon tetrachloride by alkaline activation of persulfate: Kinetic model.

Carbon tetrachloride (CT), a chlorinated organic compound widely used in the chemical industry during the 20th century, is nowadays a ubiquitous contaminant in groundwater and in situ technologies for its destruction are required. In this work, the degradation of CT by the alkaline activation of persulfate (PS) has been studied. Among the pool of radical species generated (hydroxyl radicals, sulfate radicals and superoxide radicals), O2∙- resulted to be the only species responsible for CT abatement. It has been found that the presence of other solvents less polar than water (hydrogen peroxide, acetone, propanol and methanol) improves CT degradation. Among them, methanol was selected as the most adequate co-solvent, leading to the complete elimination of CT (100 mg L-1, 24 h) with a moderate unproductive consumption of the oxidant. The degradation of CT increased proportionally with the concentration of this solvent (from 0.1 to 10 g L-1). The ratio NaOH:PS (from 1 to 8) did not affect the degradation of CT when working with a constant concentration of PS and highly alkaline conditions were maintained. The removal rate of CT increased as the concentration of PS increased (from 20 to 60 g L-1), while the conversion of this pollutant did not depend on its initial concentration (from 10 to 100 mg L-1). A kinetic model that considers the concentration of PS, MeOH and CT and can predict the concentration of CT with reaction time at different operating conditions, has been developed from the experimental data.

Síndrome general, tos y nódulo pulmonar cavitado en una paciente con VIH sin tratamiento antirretroviral / Systemic symptoms, cough and cavitated pulmonary nodule in an untreated HIV patient

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Linfangitis recidivante. Estudio causal y tratamiento

Se realiza un estudio de los pacientes con linfangitis recidivante, atendidos en la consulta de Angiología del Hospital docente V. I. Lenin en tres años (noviembre de 1979 a octubre de 1982) de acuerdo con el procedimiento terapéutico empleado. La vacunación múltiple o auto-vacuna puede ser efectiva en los pacientes portadores de linfangitis recidivante, siempre que se siga un tratamiento ininterrumpido y los consejos del facultativo. Que este metodo permite obtener el gérmen causante de la lifangitis precozmente y así realizar la elaboración de las vacunas. Que la técnica empleada para la preparación de las vacunas múltiples y auto-vacunas es el ideal por conservar el poder antigénico de la bacteria y no como lo hace el calor que le destruye los antígenos termolabiles. Que el estafilococo coagulasa positivo es el gérmen más frecuente en nuestro medio y no el estreptococo B hemolítico como lo plantean otros autores