Genes coding for enzymes of the denitrification pathway appear randomly distributed among isolates of the ancestral genus Thermus, but only in few strains of the species T. thermophilus the pathway has been studied to a certain detail. Here, we review the enzymes involved in this pathway present in T. thermophilus NAR1, a strain extensively employed as a model for nitrate respiration, on the light of its full sequence recently assembled through a combination of PacBio and Illumina technologies in order to counteract the systematic errors introduced by the former technique. The genome of this strain is divided in four replicons, a chromosome of 2,021,843 pb, two megaplasmids of 370,865 and 77,135 bp and a small plasmid of 9,799 pb. Nitrate respiration is encoded in the largest megaplasmid, pTTHNP4, within a region that includes operons for O2 and nitrate sensory systems, a nitrate reductase, nitrate and nitrite transporters and a nitrate specific NADH dehydrogenase, in addition to multiple insertion sequences (IS), suggesting its mobility-prone nature. Despite nitrite is the final product of nitrate respiration in this strain, the megaplasmid encodes two putative nitrite reductases of the cd1 and Cu-containing types, apparently inactivated by IS. No nitric oxide reductase genes have been found within this region, although the NorR sensory gene, needed for its expression, is found near the inactive nitrite respiration system. These data clearly support that partial denitrification in this strain is the consequence of recent deletions and IS insertions in genes involved in nitrite respiration. Based on these data, the capability of this strain to transfer or acquire denitrification clusters by horizontal gene transfer is discussed.

The development of a remote sensing system is proposed in the present study for monitoring of the electrical resistance of concrete in real time. The sensor is embedded in the concrete bulk, and the data are sent via a gateway to a computer for the data analysis. The sensibility of the sensors to the effect of the presence of a crystalline admixture has been also assessed in the study. Different cycles of drying and water penetration have been considered to assess the sensor performance in different water content conditions. Sensors have shown to capable of detecting changes in electrical resistance when humidity changes. The sensitive of the sensors to the action of waterproofing admixtures in the mortar has been also confirmed. The contribution of the temperature plays a critical role on the sensor response, and its simultaneous monitoring is recommended.

Background: The aim of this study was to design and analyze the content validity of an instrument to assess the risk of behaviors associated with the Chemsex phenomenon since there is currently no instrument with this objective. Method: Firstly, a bank of items identified from the literature was elaborated. Secondly, 50 experts with knowledge of the Chemsex phenomenon at the national level were contacted. A Delphi group was formed with them to carry out two rounds of item evaluation (comprehension and appropriateness) using a Likert scale of 1 to 5. To assess linguistic validity, the mean score of the item comprehension scores was used. The content validity index (CVI) and Aiken's V (VdA) were calculated for each item. A minimum value of CVI and VdA of 0.6 was established to include the items in the questionnaire. Results: In the first round of evaluation, 36 experts evaluated 114 items, of which 61 were selected. In a second round, 30 experts evaluated the 61 items selected, leaving the scale finally made up of 52 items. Conclusion: A questionnaire has been designed to assess the risk of behaviors associated with the Chemsex phenomenon. The items that make up the questionnaire have shown adequate content and linguistic validity, so this instrument can be considered valid. The Delphi method proved to be a useful technique for the proposed objective.