Experimental characterization and performance evaluation of geothermal grouting materials subjected to heating–cooling cycles

In recent years, the increasing rise in environmental awareness among energy consumers has led to an increasing use of renewable energies such as the geothermal energy. An important role in the efficient exploitation of the geothermal resource is played by the grouting material placed in the borehole between the pipes and the ground. Actually, the use of proper grouts is essential to provide an effective heat transfer between the ground and the heat carrier fluid in the pipes, and also to comply with the mechanical and environmental demands. However, when it comes to the construction of the GHP installations, the grout is especially required to be easy to work with (workable) and for this reason more water than required is sometimes added. In order to assess the suitability of grouting materials with significant water/solid ratios, the thermal conductivity, mechanical strength and permeability of five different grouts and grout–pipe specimens were measured for their laboratory characterization. In addition, the grouts were subjected to heating and cooling cycles to evaluate their durability with time in terms of the potential degradation of the materials and the loss of quality of the grout–pipe interface. According to the results obtained, the grouts here tested are appropriate for most of the geothermal heat pump installations, especially for those with low to medium ground thermal properties.The authors wish to express their gratitude to the Ministerio de Economía y Competitividad which funded this study within the Spanish National Plan for Scientific and Technical Research and Innovation (INNPACTO program) through the research project IPT-2011-0877-920000

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

Influence of limestone filler on the rheological properties of bituminous mastics through susceptibility master curves

Fuente: Construction and Building Materials[EN] Temperature variations caused by seasonal changes and vehicle loads generate severe damage to asphalt layers. For a correct design, it is essential to carry out an adequate rheological characterization of both bitumen and bituminous mastic, since they are considered the weakest elements of the mixture. This article shows the results of the rheological behavior of mastics made of limestone filler and three types of binders, with a filler-bitumen ratio of 1/1, finding that the filler-bitumen interaction has a significant influence on asphalt mastics. Vehicle loads and climatic temperatures were simulated from MSCR and DSR tests to study the viscoelastic behavior of the bitumen and the mastic. Thus, stiffness, variation of the internal structure, viscosity, thermal susceptibility, permanent deformation, and cracking were determined. The results indicated that the filler causes an increase in the rigidity of the mastic for the whole range of temperatures and load frequencies, but this increase varies depending on the type of bitumen used. There is also no significant change in the phase angle variation between bitumens and mastics. This indicates that the bitumens maintain their internal structure when the filler is added, as well as considerably decreasing the accumulated strain in multiple stress creep recovery (MSCR) tests

Eficacia del sildenafilo por vía oral como terapia de rescate en pacientes con hipertensión arterial pulmonar severa en tratamiento crónico con prostaciclina: resultados a largo plazo

Introducción y objetivo. La prostaciclina es un tratamiento eficaz en la hipertensión arterial pulmonar severa. El sildenafilo, un inhibidor selectivo de la fosfodiesterasa (PDE) tipo 5, produce vasodilatación selectiva de los vasos pulmonares, y se ha descrito un efecto sinérgico con la prostaciclina. El objetivo es analizar la eficacia y seguridad del sildenafilo como terapia de rescate en pacientes con hipertensión pulmonar (HTP) en tratamiento crónico con prostaciclina que presentan mala evolución clínica y funcional. Pacientes y método. Estudio observacional de 11 pacientes (7 varones, edad 42 ± 8 años) con hipertensión pulmonar idiopática (HTPI) en tratamiento crónico con prostaciclina. Se asoció sildenafilo oral cuando presentaban deterioro clínico o funcional. Basalmente, a los 3 y los 12 meses de tratamiento combinado, se evaluó la capacidad funcional (clase funcional [CF] de la New York Heart Association [NYHA] y prueba de los 6 min), la presencia de insuficiencia cardíaca derecha (ICD) descompensada y se realizó un ecocardiograma. Resultados. Se produjo una mejoría significativa de la capacidad de esfuerzo, con incremento de la distancia recorrida en 6 min a los 3 y los 12 meses (+25 y +36 m, respectivamente), mejoría de la CF y desaparición de la insuficiencia cardíaca en 7 de los 11 pacientes. No se observaron efectos adversos significativos. El ecocardiograma mostró una reducción significativa del diámetro diastólico del ventrículo derecho y del índice de excentricidad diastólico del ventrículo izquierdo. Un paciente falleció (muerte súbita) a los 4 meses. Conclusiones. La adición de sildenafilo al tratamiento crónico con prostaciclina en pacientes con HTP severa mejoró la capacidad funcional y disminuyó los episodios de ICD descompensada, con buena tolerancia al medicamento y sin efectos adversos graves

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

Safety of hospital discharge before return of bowel function after elective colorectal surgery

© 2020 BJS Society Ltd Published by John Wiley & Sons LtdBackground: Ileus is common after colorectal surgery and is associated with an increased risk of postoperative complications. Identifying features of normal bowel recovery and the appropriateness for hospital discharge is challenging. This study explored the safety of hospital discharge before the return of bowel function. Methods: A prospective, multicentre cohort study was undertaken across an international collaborative network. Adult patients undergoing elective colorectal resection between January and April 2018 were included. The main outcome of interest was readmission to hospital within 30 days of surgery. The impact of discharge timing according to the return of bowel function was explored using multivariable regression analysis. Other outcomes were postoperative complications within 30 days of surgery, measured using the Clavien–Dindo classification system. Results: A total of 3288 patients were included in the analysis, of whom 301 (9·2 per cent) were discharged before the return of bowel function. The median duration of hospital stay for patients discharged before and after return of bowel function was 5 (i.q.r. 4–7) and 7 (6–8) days respectively (P < 0·001). There were no significant differences in rates of readmission between these groups (6·6 versus 8·0 per cent; P = 0·499), and this remained the case after multivariable adjustment for baseline differences (odds ratio 0·90, 95 per cent c.i. 0·55 to 1·46; P = 0·659). Rates of postoperative complications were also similar in those discharged before versus after return of bowel function (minor: 34·7 versus 39·5 per cent; major 3·3 versus 3·4 per cent; P = 0·110). Conclusion: Discharge before return of bowel function after elective colorectal surgery appears to be safe in appropriately selected patients