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miércoles, 24 de julio de 2013

Antibiotic resistance: The last resort

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Oficiales de salud observan con horror como las bacterias llegan a ser resistente al poderoso antibiótico carbapenema, uno de los más recientes medicamentos en los estantes.
Como regla, los oficiales de salud de alto rango evitan utilizar adjetivos apocalípticos. Por lo que fué preocupante escuchar a Thomas Frieden y Sally Davies advertir de la "pesadilla" que se acerca y de la "amenaza catastrófica" con pocos días de diferencia en Marzo.
Los oficiales estaban hablando de el incremento en una clase de bacteria poco conocida, resistente a antibióticos: Enterobacterias resistentes al cabapenema (CREs). Davies, Oficial Médico en Jefe del Reino Unido, describe a los CREs como un riesgo tan serio como el terrorismo. "Tenemos un problema muy serio, y necesitamos sonar la alarma", mencionó Frieden, director del CDC en Atlanta Georgia.
Estas baceries ocasionan infecciones en vejiga, pulmones y sangre, causando shock séptico y amanazar la vida.
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lunes, 15 de julio de 2013

Bioaerosols in the Workplace: Evaluation, Control and Prevention Guide

Microorganisms are ubiquitous in any environment and are called bioaerosols when they are present in the air. While no inhalation exposure standard has yet been established, the international scientific community nevertheless acknowledges that some bioaerosols have an adverse effect on air quality and workers’ health. This well-illustrated practical guide describes the approach recommended by the IRSST for the evaluation, control and prevention of bioaerosol exposure. It contains a synthesis of the most recent information on bioaerosols in the workplace and their effects on health, a discussion of concentrations measured in different contexts, and proposed exposure values. The guide describes evaluation strategies as well as methods for the interpretation and application of results. Finally, it presents strategies and methods for the control and prevention of bioaerosol exposure, and discusses certain specific cases. This guide, which explains the possibilities and limitations of such an approach, is aimed at stakeholders in all sectors in which bioaerosols can be present in high concentrations.
Bioaerosols in the Workplace: Evaluation, Control and Prevention Guide. Goyer, N; Lavoie, J; Lazure, L; Marchand, G. Studies and Research Projects / Technical Guide  T-24, Montréal, IRSST, 2001, 72 pages

lunes, 8 de julio de 2013

Heating, Ventilation and Air Conditioning - Validation of System Cleaning Initiation Criteria under Real Conditions

The cleanliness of a ventilation system invariably affects the quality of the air that it distributes. However, it is difficult for building managers to assess the relevance of having their systems cleaned and to choose from among all the proposals from cleaning specialists because no objective method exists for evaluating the dustiness of systems. In the context of a previous project, the researchers developed a method for collecting surface dusts in heating, ventilation and air conditioning (HVAC) ducts and identified criteria for initiating cleaning. The method was validated in the laboratory and compared to those methods mentioned in the scientific literature [Association pour la prévention et l’étude de la contamination (ASPEC), of France, and the National Air Duct Cleaners Association (NADCA), of the United States]. They all proved feasible by using their corresponding cleaning initiation criterion.
In a new study, which this report describes, the same team validated the criteria for these methods in the ventilation systems of occupied non-industrial buildings. Once again, the results were conclusive. Building managers can now rely on the objective criteria of the offered methods, rather than basing themselves solely on visual inspection, which is subjective.

Heating, Ventilation and Air Conditioning - Validation of System Cleaning Initiation Criteria under Real Conditions.

lunes, 1 de julio de 2013

Development of a Procedure to Measure the Effectiveness of N95 Respirator Filters against Nanoparticles

There is an increasing concern about the potential health hazards posed to workers exposed to inhalation of nanoparticles (NPs). Common sources of nanoparticles in working environments include fumes and exhausts from different processes like laser ablation and milling. Nanoparticles have potential toxic properties: a high particle surface area, number concentration, and surface reactivity. Inhalation, the most common route of nanoparticle exposure, has been shown to cause adverse effects on pulmonary functions, and the deposited particles in the lung can be translocated to the blood system by passing through the pulmonary protection barriers. Filtration is the simplest and most common method of aerosol control. It is widely used in mechanical ventilation and respiratory protection. However, concerns have been raised regarding the effectiveness of filters for capturing nanoparticles.
In this study, the performance of one model of N95 NIOSH approved filtering face-piece respirator (FFR) was characterized against poly-dispersed and mono-dispersed NPs using two different experimental set-ups. With poly-dispersed NPs, a methodology was developed to measure the performance of the N95 respirators against NaCl aerosols in the size range of 15 to 200 nm in three scenarios. First, the initial particle penetration through N95 respirator was examined at four constant airflow rates: 85, 135, 270 and 360 liters/min. Second, the effect of time on the particle loading was investigated for duration of five hours. Third, the effect of the relative humidity (RH) (10, 30 and 70%) on the particle penetration was assessed at 85 liters/min.
Development of a Procedure to Measure the Effectiveness of N95 Respirator Filters against Nanoparticles