RESUMEN
In this work, a numerical analysis of three different flat plate solar collectors was conducted using their entropy generation rates. Specifically, the Computational Fluid Dynamics (CFD) technique was used to compare the detailed performance of conventional and zigzag tube geometries of flat plate solar collectors (FPCs) in terms of their entropy generation rates. The effects of fluid viscosity, heat transfer, and heat loss of the flat plate solar collectors were considered for the local and global entropy generation rate analyses. Variations on the inlet volumetric flow rate of the FPCs from 1.0 to 9.0 L/min were simulated under the average solar radiation for one year in the state of Guanajuato, Mexico. The results illustrate and discuss the temperatures, pressures, and global entropy generation rates for volumetric flow variations. The velocity, temperature, and pressure distributions and the maps of the local entropy generation rates inside the collectors are presented and analyzed for the case with a flow rate of 3.0 L/min. These results demonstrate that the zigzag geometries achieved higher outlet temperatures and greater entropy generation rates than the conventional geometry for all the volumetric flow rates considered.
RESUMEN
This study has established that there were no changes in the general structure of LPS of Shigella flexneri M90T either when the bacteria grew free in the cytoplasm of the eucaryotic host cell or during extracellular growth in liquid LB medium at 37 degrees C. In both cases there was a similar bi-modal O-antigen chain length distribution with the mean modal values between 1 and 2, and between 11 and 14 subunits. This suggests that the intracellular localization is not a significant stimulus perceived by Shigella to regulate the length of its O-side chains. However, when the bacteria grew under extracellular conditions (liquid medium) at 30 degrees C, even though there were no changes in the modal values, the pattern of the O-antigen chain length distribution of LPS was different, with an increase in the amount of the long chains relative to the short chains.
Asunto(s)
Antígenos O/análisis , Shigella flexneri/química , Espacio Extracelular , Células HeLa , Humanos , Líquido Intracelular , Lipopolisacáridos/análisis , Shigella flexneri/crecimiento & desarrolloRESUMEN
A study was carried out in Sancti Spiritus Province in the 1984-1986 period about the results of the treatment of lip cancer. Male patients were the most affected by lip cancer (CIE 8-140) in our series. The place of the tumor was predominantly the lower lip (p less than or equal to 0.001). Surgical treatment was used in 96.8% of the cases and the cuneiform (wedge-shaped) exeresis was the most commonly used method in the early stages of the disease (T1 y T2). Castañón keloplasty was the reconstructive procedure used in 18.7% of the patients. Local sepsis was present in 31.2% of the patients undergoing surgery, occurring most frequently in upper lip tumors.