Fire simulator exposure alters the innate epithelial response and inflammatory status in the airways of firefighters.

BACKGROUND: Firefighters are often exposed to high temperatures and by-products of combustion, which can compromise their health. We aimed to evaluate the effect of fire exposure in fire simulators on the airways of firefighters at different time-points. METHODOLOGY: Thirty-seven male firefighters exposed to fire simulators were evaluated in three phases: pre-exposure, at the end of the first week, and 4 weeks after. Pulmonary function by spirometry, nasal mucociliary clearance; peripheral oxygen saturation, inflammatory markers in the nasal lavage and CC16 in the sputum, nasal obstruction, and quality of life (using the questionnaires NOSE and SNOT-22) were assessed. RESULTS: Higher levels of IL-8, IL-10, and exhaled carbon monoxide were found more in phase 2 than in phase 1. Higher CC16 levels and lower peripheral oxygen saturation were observed in phase 3 as compared to phase 1. Lower levels of IL-2 and peripheral oxygen saturation were found in phase 3 than in phase 2. Higher nasal mucociliary clearance, as well as the worst quality of life and nasal obstruction, were observed in phases 2 and 3 as compared to phase 1. CONCLUSIONS: The firefighters’ exposures to high temperatures and by-products of combustion in the fire simulators elicit an inflammatory process in the airways with impairment in the innate epithelial response of the upper airway lining. Furthermore, changes in O2 transport affected the professionals’ quality of life negatively.

Conjuring up a ghost: structural and functional characterization of FhuF, a ferric siderophore reductase from E. coli.

Iron is a fundamental element for virtually all forms of life. Despite its abundance, its bioavailability is limited, and thus, microbes developed siderophores, small molecules, which are synthesized inside the cell and then released outside for iron scavenging. Once inside the cell, iron removal does not occur spontaneously, instead this process is mediated by siderophore-interacting proteins (SIP) and/or by ferric-siderophore reductases (FSR). In the past two decades, representatives of the SIP subfamily have been structurally and biochemically characterized; however, the same was not achieved for the FSR subfamily. Here, we initiate the structural and functional characterization of FhuF, the first and only FSR ever isolated. FhuF is a globular monomeric protein mainly composed by α-helices sheltering internal cavities in a fold resembling the "palm" domain found in siderophore biosynthetic enzymes. Paramagnetic NMR spectroscopy revealed that the core of the cluster has electronic properties in line with those of previously characterized 2Fe-2S ferredoxins and differences appear to be confined to the coordination of Fe(III) in the reduced protein. In particular, the two cysteines coordinating this iron appear to have substantially different bond strengths. In similarity with the proteins from the SIP subfamily, FhuF binds both the iron-loaded and the apo forms of ferrichrome in the micromolar range and cyclic voltammetry reveals the presence of redox-Bohr effect, which broadens the range of ferric-siderophore substrates that can be thermodynamically accessible for reduction. This study suggests that despite the structural differences between FSR and SIP proteins, mechanistic similarities exist between the two classes of proteins.

Calculation of conversion coefficients for air kerma to ambient dose equivalent using transmitted spectra of megavoltage X-rays through concrete.

With the fast advancement of technology, (60)Co teletherapy units are largely being replaced with medical linear accelerators. In most cases, the linear accelerator tends to be installed in the same room in which the (60)Co teletherapy unit was previously placed. If in-depth structural remodelling is out of the question, high-density concrete is usually used to improve shielding against primary, scatter and leakage radiation originating in the new equipment. This work presents a study based on Monte Carlo simulations of the transmission of some clinical photon spectra (from 6, 10, 15, 18 and 25 MV accelerators) through concrete, considering two different densities. Concrete walls with thickness ranging from 0.70 to 2.0 m were irradiated with 30 cm×30 cm primary beam spectra. The results show that the thickness of the barrier decreases up to ∼65 % when barite (high-density concrete) is used instead of ordinary concrete. The average energies of primary and transmitted beam spectra were also calculated. In addition, conversion coefficients from air kerma to ambient dose equivalent, H*(d)/K(air), and air kerma to effective dose, E/K(air), for photon spectra from the transmitted spectra were calculated and compared. The results suggest that the 10-mm depth is not the best choice to represent the effective dose.

[Violence, ethnic groups and skin color: a study on differences in the metropolitan region of Salvador, Bahia, Brazil]. / Violência, etnia e cor: um estudo dos diferenciais na região metropolitana de Salvador, Bahia, Brasil.

The objective of this study was to analyze the distribution of various forms of violence--structural, institutional, interpersonal, and crime-related--in the three most common color groups of Bahian society: mulattos, whites, and blacks. The study compared the levels of victimization of mulatto, white, and black individuals with their assessments of the efficiency of crime-control institutions, in order to ascertain how that relates to those same citizens' acceptance of authoritarian attitudes and norms. The data analyzed came from the multicenter project on Attitudes and Cultural Standards about Violence (ACTIVA) project, from a sample of 1,384 residents of the Salvador metropolitan region. The study was designed as a cross-sectional survey, with interviews done in the people's homes between September and December of 1996. The sample selection was done in three stages: first, residential areas were chosen at random; then, a systematic selection was made from the homes in each of the selected areas; finally, the persons to be interviewed were chosen at random. To collect the data the researchers used a pretested questionnaire that had been designed for the ACTIVA study. The results showed an unequal distribution of structural violence that mainly affected blacks. There were no differences by color group for interpersonal and institutional violence. Criminal violence impacted whites and blacks to the same degree. Distrust in the efficiency of the civil and military police and in the justice and penal systems was very high among all three color groups. Moreover, few differences were found among the groups with regard to authoritarian attitudes and norms. Based on the results, it is possible to conclude that public order is threatened if the dissatisfaction with institutions for crime prevention and reduction continues at a high level at the same time that individuals tend to support violence to resolve conflicts.