Increased expression and activity of sodium channels in alveolar type II cells of hyperoxic rats.

We investigated the cellular and molecular events associated with the increase in sodium transport across the alveolar epithelium of rats exposed to hyperoxia (85% O2 for 7 days followed by 100% O2 for 4 days). Alveolar type II (ATII) cell RNA was isolated and probed with a cDNA for one of the rat colonic epithelial sodium channel subunits (alpha rENaC). The alpha rENaC mRNA (3.7-kb transcript) increased 3-fold in ATII cell RNA isolated from rats exposed to 85% O2 for 7 days and 6-fold after 4 days of subsequent exposure to 100% O2. In situ hybridization revealed increased expression of alpha rENaC mRNA transcripts in both airway and alveolar epithelial cells of hyperoxic rats. When immunostained with a polyclonal antibody to kidney sodium channel protein, ATII cells from hyperoxic rats exhibited a significant increase in the amount of immunogenic protein present in both the plasma membrane and the cytoplasm. When patched in the whole-cell mode, ATII cells from hyperoxic rats exhibited amiloride and 5-(N-ethyl-N-isopropyl)-2',4'-amiloride (EIPA)-sensitive currents that were 100% higher compared with those obtained from air-breathing rats. Single-channel sodium currents (mean conductance of 25 pS) were seen in ATII cells patched in both the inside-out and cell-attached modes. The number and open probability of these channels increased significantly during exposure to hyperoxia. Exposure to sublethal hyperoxia up-regulated both alpha rENaC mRNA and the functional expression of sodium channels in ATII cells.

Identification of technological districts: the case of Spain

Paper submitted to the 51st European Congress of the Regional Science Association International, 37th Spanish Regional Science Association Conference, Barcelona, August 30-September 3, 2011.

Influence of characteristics of irrigation channels on the breeding bird community of a wetland zone in southeast of Spain

The “El Hondo Nature Park” is mainly composed of a series of irrigation channels and water reservoirs, subjected to various regimes of management as well as reed and vegetation control, thus creating a great variety of habitats and situations. To determine the influence of these habitats and management regimes on the local bird community, a set of characteristics of these channels and their surrounding area were analysed with a Correspondence Analysis (CA). The degree of reed development in channels and the presence in the surroundings of orchards and other reed formations were the most decisive factors to explain the probability of occurrence of reed birds and waterbirds, as well as bird species richness and abundance. Other bird species were not directly influenced by channel variables, but only by those of surrounding land uses.

Assessment of corrective measures for alleviating slope instabilities in carbonatic Flysch formations: Alicante (SE of Spain) case study

As is well known, in order to select remediation measures to correct or prevent slope instabilities, it is essential to identify and characterize the instability mechanisms. This task is especially complex for heterogeneous rock masses such as Flysch formations. This paper addresses the assessment of corrective measures used in carbonate Flysch formations by classifying and grouping field data reported in an available database in order to associate this data with various instability mechanisms and stratigraphic column types as well as with the corrective measures taken to stabilise them. For this purpose, 194 slopes have been geomechanically characterized, mainly by considering the observed instability mechanisms. The corrective measures that were applied have been evaluated for their suitability and performance, and, if applicable, the causes of their malfunction have been also studied. As a result, some guidelines based on the observed behaviour and the suitability of the correction measure as a function of instability type are proposed for similar slopes.