Estudio de la resistencia mecánica a la compresión de ladrillos elaborados a partir de mezclas arcilla roja-cemento Portland

A proposal for the development of handcrafted bricks of clay soil stabilized with gray portland cement, as an alternative to reduce the level of pollution caused by emissions of carbon dioxide from the use of wood as a source of combustion during the baking step of bricks is presented. The work was carried out in the soil bank of one brickyard located in La Paz Centro, Nicaragua. Moreover, two different brands of Portland cement were used. Cement/soil samples were prepared according to the established norms, and the mechanical-physical properties were compared with bricks cooked through a full mixed factorial design experiment. The parameters studied were ratios of cement /soil, water /cement binder and cement brand. The best results for samples of cement/soil reached resistances higher than 12 MPa after 28 days of curing and absorption percentages lower than 15%. Hydration products, responsible for the development of mechanical strength, were analyzed using infrared spectroscopy. The largest number of hydrated calcium silicate was obtained for samples with Canal cement. DOI: http://dx.doi.org/10.5377/nexo.v27i2.1945Se presenta una propuesta para la elaboración de ladrillos artesanales a base del suelo arcilloso estabilizado con cementoPortland gris, como alternativa para reducir el grado de contaminación causado por emisiones de dióxido de carbono a causadel uso de madera, usada como fuente de combustión durante la etapa de cocción de los ladrillos elaborados artesanalmente anivel nacional. Se trabajó básicamente con el banco de suelo de una de las ladrilleras ubicada en La Paz Centro, Nicaragua ydos marcas diferentes de cemento portland. Se elaboraron muestras de cemento/suelo según las normas y se compararon laspropiedades físico mecánicas con los ladrillos cocidos por medio de un diseño de experimento de tipo factorial mixto completo.Los factores que se estudiaron fueron las porciones de cemento/suelo, agua/ligante y marca de cemento. Los mejores resultadospara muestras de cemento/suelo presentaron resistencias superiores a los 12 MPa después de 28 días de curado y porcentajes deabsorción inferiores al 15%. Los productos de hidratación responsables del desarrollo de la resistencia mecánica se analizaronpor medio de pruebas de espectroscopia infrarroja, mostrando la mayor cantidad de silicatos de calcio hidratado en muestras concemento Canal.DOI: http://dx.doi.org/10.5377/nexo.v27i2.194

Valorización de ceniza de bagazo de caña de la industria azucarera Nicaragüense como sustituto parcial al cemento Portland

In this study, the use of the ashes of sugarcane bagasse (ASB) from Monte Rosa sugarcane mill (Nicaragua) as an alternative material to Portland Cement (PC) was evaluated. The evaluation was performed through studies of advanced characterization and mechanical properties in pastes with 15% and 45% substitution of PC. Moreover, 100% PC pastes were used as reference. The mechanical resistance (MR), the consumption of calcium hydroxide and the development of reaction products were measured. The results showed that the highest values of MR were obtained for the reference pastes, thus indicating that the MR decreased with increase in the degree of substitution. Through the analysis of X-ray diffraction (XRD) and thermal analysis TGA / DTA was found that the consumption of Ca(OH)2 gave rise to the formation of CSH gel as the main product of hydration and caused the gain in the mechanical properties. The reaction products were observed by scanning electron microscopy (SEM) where the mechanism in solid state was noticeable. From this result, it can be concluded that the ASB are pozzolanic material with a better reactivity to Ca(OH)2 with 15% of substitution. DOI: http://dx.doi.org/10.5377/nexo.v27i2.1944En este estudio, se presenta la valoración del uso de las cenizas de bagazo de caña (CBCA) proveniente del Ingenio Monte Rosa(Nicaragua) como material alternativo al cemento Portland (CP) mediante estudios de caracterización avanzada y propiedadesmecánicas, en pastas endurecidas de CP sustituidas en 15 y 45 % por CBCA; además se utilizó pastas de referencia con 100 %CP sobre las cuales se evaluó las resistencias mecánicas (RM), el consumo de hidróxido de calcio y el desarrollo de losproductos de reacción. Los resultados revelaron que los valores más altos de RM reportados fueron por el sistema de referencia,indicando que la RM disminuyó con el incremento en el porcentaje de sustitución. Por medio de los análisis de difracción derayos X (DRX) y análisis térmicos por ATG/ATD fue demostrado el consumo de Ca(OH)2 que dio lugar a la formación de gelCSH como principal producto de hidratación y responsable de la ganancia de las propiedades mecánicas. Los productos dereacción fueron observados también por microscopia electrónica de barrido (MEB) donde el mecanismo en estado sólido fuenotable. A partir de estos resultados se puede concluir que las CBCA son un material puzolánico con una mejor reactividadfrente al Ca(OH)2 con 15 % de sustitución.DOI: http://dx.doi.org/10.5377/nexo.v27i2.194

International nosocomial infection control consortium (INICC) report, data summary of 36 countries, for 2004-2009

The results of a surveillance study conducted by the International Nosocomial Infection Control Consortium (INICC) from January 2004 through December 2009 in 422 intensive care units (ICUs) of 36 countries in Latin America, Asia, Africa, and Europe are reported. During the 6-year study period, using Centers for Disease Control and Prevention (CDC) National Healthcare Safety Network (NHSN; formerly the National Nosocomial Infection Surveillance system [NNIS]) definitions for device-associated health care-associated infections, we gathered prospective data from 313,008 patients hospitalized in the consortium's ICUs for an aggregate of 2,194,897 ICU bed-days. Despite the fact that the use of devices in the developing countries' ICUs was remarkably similar to that reported in US ICUs in the CDC's NHSN, rates of device-associated nosocomial infection were significantly higher in the ICUs of the INICC hospitals; the pooled rate of central line-associated bloodstream infection in the INICC ICUs of 6.8 per 1,000 central line-days was more than 3-fold higher than the 2.0 per 1,000 central line-days reported in comparable US ICUs. The overall rate of ventilator-associated pneumonia also was far higher (15.8 vs 3.3 per 1,000 ventilator-days), as was the rate of catheter-associated urinary tract infection (6.3 vs. 3.3 per 1,000 catheter-days). Notably, the frequencies of resistance of Pseudomonas aeruginosa isolates to imipenem (47.2% vs 23.0%), Klebsiella pneumoniae isolates to ceftazidime (76.3% vs 27.1%), Escherichia coli isolates to ceftazidime (66.7% vs 8.1%), Staphylococcus aureus isolates to methicillin (84.4% vs 56.8%), were also higher in the consortium's ICUs, and the crude unadjusted excess mortalities of device-related infections ranged from 7.3% (for catheter-associated urinary tract infection) to 15.2% (for ventilator-associated pneumonia). Copyright © 2012 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved

Virus del moquillo en fauna silvestre en el norte de España

Trabajo presentado a la: XXXIII Reunión de la Sociedad Española de Anatomía Patológica Veterinaria (SEAPV). Lugo. P11. 15-17 junio.Trabajo financiado por los proyectos I+D+i RTI2018-096010-B-C21- MCIN/AEI/10.13039/ 501100011033/FEDER y PCTI 2021-2023 (GRUPIN: IDI-2021- 000102

Impact of International Nosocomial Infection Control Consortium (INICC) strategy on central line-associated bloodstream infection rates in the intensive care units of 15 developing countries

BACKGROUND. The International Nosocomial Infection Control Consortium (INICC) was established in 15 developing countries to reduce infection rates in resource-limited hospitals by focusing on education and feedback of outcome surveillance (infection rates) and process surveillance (adherence to infection control measures). We report a time-sequence analysis of the effectiveness of this approach in reducing rates of central line-associated bloodstream infection (CLABSI) and associated deaths in 86 intensive care units with a minimum of 6-month INICC membership. METHODS. Pooled CLABSI rates during the first 3 months (baseline) were compared with rates at 6-month intervals during the first 24 months in 53,719 patients (190,905 central line-days). Process surveillance results at baseline were compared with intervention period data. RESULTS. During the first 6 months, CLABSI incidence decreased by 33% (from 14.5 to 9.7 CLABSIs per 1,000 central line-days). Over the first 24 months there was a cumulative reduction from baseline of 54% (from 16.0 to 7.4 CLABSIs per 1,000 central line-days; relative risk, 0.46 [95% confidence interval, 0.33-0.63]; P < .001). The number of deaths in patients with CLABSI decreased by 58%. During the intervention period, hand hygiene adherence improved from 50% to 60% (P < .001); the percentage of intensive care units that used maximal sterile barriers at insertion increased from 45% to 85% (P < .001 ), that adopted chlorhexidine for antisepsis increased from 7% to 27% (P=.018 ), and that sought to remove unneeded catheters increased from 37% to 83% (P=.004); and the duration of central line placement decreased from 4.1 to 3.5 days (P < .001). CONCLUSIONS. Education, performance feedback, and outcome and process surveillance of CLABSI rates significantly improved infection control adherence, reducing the CLABSI incidence by 54% and the number of CLABSI-associated deaths by 58% in INICC hospitals during the first 2 years. © 2010 by The Society for Healthcare Epidemiology of America. All rights reserved