Utility of exhaled breath condensate pH for diagnosing occupational asthma.

INTRODUCTION: The current reference standard method for diagnosing occupational asthma (OA) is specific inhalation challenge (SIC) with the suspected agent. The alternative method is serial peak expiratory flow (PEF) monitoring. Nevertheless, PEF does not have optimal sensitivity and specificity for this purpose. The aim of this study was to evaluate the utility of exhaled breath condensate (EBC) pH for the diagnosis of OA. MATERIAL AND METHODS: A prospective study was performed in 37 subjects with suspected OA. Serial PEF monitoring was carried out for 2 weeks at work and for 2 weeks off work. At the end of each period, the EBC pH and the methacholine concentration resulting in a 20% FEV(1) decrease (PC20) were measured. SIC was subsequently performed. PEF graphs were interpreted visually by 3 experienced independent readers. RESULTS: Seventeen patients tested positive with SIC. Receiver-operating characteristic curves showed that a decrease in EBC pH greater than 0.4 units during the period at work compared to the off-work period achieved the most satisfactory sensitivity (40%, CI 19.4-66.5) and specificity (90%, CI 66.9-98.2) for diagnosing OA. When EBC pH findings were added to PEF results, the diagnostic yield of PEF generally increased. Other test combinations (e.g. EBC pH plus PC20 or EBC pH plus PC20 plus PEF) did not improve diagnostic performance. CONCLUSIONS: Acidification of EBC pH at work and adding the EBC pH measurement to PEF monitoring during periods at work and off work may be useful for improving the diagnosis of OA.

Daily data of Global Vertical Insolation in the four cardinal orientations in Burgos, Spain.

Daily data of Global, Diffuse and Beam Horizontal Insolation and Global Vertical (North, South, East and West orientations) insolation recorded in Burgos, Spain, are presented in this paper. Ten-minute irradiance data sets are collected over forty-five months in the experimental campaign to produce estimates of daily insolation levels. This data was derived in association with the article titled: "The PV Potential of Vertical Façades: a classic approach using experimental data from Burgos, Spain" (Díez-Mediavilla et al., in press) [1]. This dataset can be used to develop and test new solar radiation and daylight models and estimate the thermal load and lighting needs in buildings for the improvement of energy efficiency.

Differential scanning potentiometry: surface charge development and apparent dissociation constants of natural humic acids.

Humic acids (HA) are the main components of soil organic matter which can form complexes with metal ions and other soil and/or water contaminants. Here, we focus on their acid-base properties. HA were extracted from two different soils (Tipic Ustifluvent and Entic Haplustoll) with different vegetation. In this study we use a simple method, differential scanning potentiometry (DSP), to determine HA buffer capacity distribution, apparent dissociation constant values and surface charge development.