Acetylene soot reaction with NO in the presence of CO.

The heterogeneous reaction of soot with NO can be considered as a means of reduction of the emissions of both pollutants from combustion systems. In this paper, the influence of the presence of CO in the soot-NO reaction is studied. Soot was obtained by pyrolysis at 1373 K of 5000 ppmv acetylene in nitrogen. The study of the influence of CO on the soot-NO reaction was performed in experiments fixing NO concentration at 900 ppmv and introducing different CO concentrations among 0 and 9900 ppmv. An increase in both the carbon consumption rate and NO reduction by acetylene soot was observed as the concentration of CO increases. These results can be explained by the oxide-stripping reaction, CO+C(f)(O)-->CO(2)+C(f). The direct reaction of CO with NO catalyzed by the carbon surface, CO+NO-->CO(2)+1/2N(2) may not be considered in this case the dominant process due to the absence of mineral impurities in the acetylene soot. The influence of CO in the acetylene soot-NO reaction was also tested in the presence of oxygen (250-5000 ppmv). In these conditions and for relatively high CO/O(2) ratios, CO seems to also contribute to NO reduction by the previous oxide-stripping reaction.

Evisceración vaginal seis meses después de histerectomía / Transvaginal evisceration six months after hysterectomy

Presentamos un caso de evisceración vaginal en una mujer posmenopáusica sometida, 6 meses antes, a histerectomía vaginal, cuya reparación se realizó por vía abdominal mediante cierre de la cúpula vaginal y colocación de malla de Gore-Tex® para refuerzo del suelo pelviano. El diagnóstico y la reparación tempranos de este raro problema urgente llevan a evitar la resección intestinal y a una buena recuperación de las pacientes. En la intervención debe valorarse la presencia de defectos del suelo pelviano que contribuyan a la evisceración. (AU)