Presence of emerging organic contaminants and solvents in schools using passive sampling.

In this study, we report on the applicability of passive sampling with Carbopack X adsorbent tubes followed by thermal desorption gas-chromatography-mass spectrometry (TD-GC-MS) to monitor the concentrations of emerging organic contaminants (EOCs) and solvents in ten indoor environments in a conventional and a vocational training school. However, if passive sampling is to be used as a reliable sampling technique, a specific diffusive uptake rate is required for each target compound. Accordingly, the aim of the present study was twofold. The first was to determine the experimental diffusive uptake rates of the target EOCs and solvents in one of the sampling sites of the vocational training school using Carbopack X adsorbent tubes and active sampling as the reference technique. The results showed experimental diffusive uptake rates between 0.46 mL min-1 and 0.94 mL min-1 with RSD % below 5% for the 28 target compounds. The second was to apply the uptake rates obtained experimentally to determine EOCs and solvents in schools. The monitoring results showed that solvents were ubiquitous throughout the conventional school with a concentrations range between 51.93 µg m-3 and 164.6 µg m-3, while EOCs were detected to a lesser extent. Moreover, the concentrations of EOCs in the vocational training school were much higher than those in the conventional school with concentrations of up to 562.9 µg m-3 for solvents and 344.3 µg m-3 for acrylate polymer monomers. After actively sampling for seven days in each school, we concluded that the concentrations of EOCs and solvents found are mostly linked to cleaning products (conventional school) and the activities carried out in the classroom (vocational training school).

Passive sampling to control air quality in schools: Uptake rate determination and application.

In this paper, we provide a detailed description of the application of passive sampling with Carbopack X tubes followed by thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) to determine the concentrations of volatile organic compounds (VOCs) in different school environments. The main objective of the study was to monitor VOCs in seven indoor and three outdoor environments at a school in Tarragona, Spain. However, in order to obtain more accurate information, it was necessary to determine the experimental diffusive uptake rates of the target VOCs in indoor settings through parallel passive and active sampling in one classroom. The results showed experimental diffusive uptake rates in the range of 0.38 mL min-1 and 0.95 mL min-1 with RSD % below 5% for up to 44 VOCs. The monitoring results showed that ethanol (23.84-83.16 µg m-3 ) and isopropyl alcohol (5.42-25.92 µg m-3 ) were the most common compounds found in indoor environments, with cleaning products as the main emission source. The VOCs i-pentane and n-pentane were found at the highest concentrations in the three sampling sites set in the school's playground, and their concentrations were strictly related to combustion processes from automobile traffic.

Contaminación acústica en un servicio de urgencias hospitalarias / Noise pollution in a Hospital Emergency Unit

Objetivo: conocer los niveles de ruido existentes en el Servicio de Urgencias (SU) de un hospital universitario e identificar las principales fuentes que lo generan. Método: estudio observacional descriptivo. Se realizaron mediciones del ruido en las distintas áreas del SU del Hospital Universitario Sant Joan de Reus (Tarragona), entre abril y septiembre de 2016. Se utilizó un sonómetro que registraba la actividad acústica en decibelios (dB9 en un software, para su posterior análisis e interpretación). Se llevó a cabo análisis descriptivo con el programa estadístico SPSS versión 23.0. Resultados: se realizaron 42 mediciones. La media (desviación estándar o DE) de ruido en todas las áreas del SU fue de 61,38 (4,90) dB. La media (DE) de ruido en las Urgencias de Pediatría fue 58,16 (4,09) dB, en las Urgencias Generales 63,91 (3,23) dB, en la sala de espera de adultos de 62,76 (6,92) dB, en el Área de Atención Rápida de 57,43 (2,74) dB, en el Área de Observación de 59,18 (5,67) dB. Conclusiones: los niveles de ruido medidos en el SU son altos y superan los límites recomendados por la Organización Mundial de la Salud (OMS). Se identificaron como principales fuentes generadoras de ruido la megafonía, las alarmas acústicas y en especial la comunicación interpersonal, sobre todo durante los cambios de turno

Objective: to understand the noise levels existing at the Emergency Unit (ER) of a University Hospital, and to identify the main sources that generate it. Method: a descriptive observational study. Noise measurements were conducted in the different areas of the Emergency Unit of the Hospital Universitario Sant Joan de Reus (Tarragona), between April and September, 2016, using a sound level meter that recorded the acoustic activity in decibels (dB9 in software, for its subsequent analysis and interpretation). Descriptive analysis was conducted with the statistical program SPSS version 23.0. Results: forty-two (42) measurements were conducted. The mean (standard deviation or SD) noise in all areas of the Emergency Unit was 61.38 (4.90) dB. The mean (SD) noise in the Pediatric Emergency Unit was 58.16 (4.09) dB; and it was of 63.91 (3.23) dB in General Emergencies, 62.76 (6.92) dB in the Adult Waiting Room, 57.43 (2.74) dB in the Urgent Care Area, and 59.18 (5.67) dB in the Observation Area. Conclusions: the noise levels measured at the Emergency Unit are high and exceed the limits recommended by the World Health Organization (WHO). The main sources generating noise were identified as the loudspeaker system, the acoustic alarms, and particularly interpersonal communication, particularly during shift changes

New insights into the toxicity mechanism of octanoic and decanoic acids on Saccharomyces cerevisiae.

Octanoic (C8) and decanoic (C10) acids are produced in hypoxic conditions by the yeast Saccharomyces cerevisiae as by-products of its metabolism and are considered fermentation inhibitors in the presence of ethanol at acidic pH. This study aims to broaden our understanding of the physiological limits between toxicity and ester production in yeast cells. To this end, the non-inhibitory concentration (NIC) and maximum inhibitory concentration (MIC) values were first established for C8 and C10 at physiological pH (5.8) without ethanol. The results showed that when these acids were added to culture medium at these values, they tended to accumulate in different cellular fractions of the yeast. While C8 was almost entirely located in the cell wall fraction, C10 was found in the endocellular fraction. Cell fatty acid detoxification was also different; while the esterification of fatty acids was more efficient in the case of C10, the peroxisome was activated regardless of which fatty acid was added. Furthermore, the study of the Pdr12 and Tpo1 transporters that evolved during the detoxification process revealed that C8 was mostly expelled by the Pdr12 carrier, which was related to higher ß-oxidative damage in the presence of endocellular C10. C10 is more toxic at lower concentrations than C8. Although they are produced by yeast, the resulting intracellular medium-chain fatty acids (MCFAs) caused a level of toxicity which promoted cell death. However, MCFAs are involved in the production of beverage flavours.

New insights into the capacity of commercial wine yeasts to grow on sparkling wine media. Factor screening for improving wine yeast selection.

During the production of sparkling wine, wine yeasts are subjected to many stress factors apart from ethanol, which lead to the need to achieve their acclimation in line with various industrial protocols. In the present work, 44 commercial wine Saccharomyces cerevisiae strains and one laboratory strain (BY4742) were firstly subjected to the influence of increasing concentrations of ethanol to cluster the yeasts using discriminant function analysis. Afterwards, non-inhibitory concentration (NIC) and minimum inhibitory concentration (MIC) were estimated, revealing some differences between 24 of these strains. Meanwhile, this study confirms the negative synergistic effect of low pH with ethanol on the maximum specific growth rate (µmax) and lag phase time. Moreover, a negative effect of increasing levels of glycerol in the growth medium was observed. Interestingly enough, an interactive positive effect was found between cysteine and medium-chain fatty acids (MCFA). While cysteine did not have a really significant effect in comparison to the control, it was able to restore the damage caused by MCFA, making the growth rate of cells recover and even reducing the formation of reactive oxygen species. Adequate culture aeration is also crucial for the composition of the cell fatty acid. The final results showed that few differences were observed between NIC and MIC estimations with respect to cells pre-cultured in the presence or absence of oxygen.

Metabolomic charactetization of yeast cells after dehydration stress

In this study, we analyzed the metabolite features of the yeasts Saccharomyces cerevisiae, Naumovia castellii, and Saccharomyces mikatae. The three species are closely related genetically but differ in their tolerance of desiccation stress. Specifically, we determined whether certain metabolites correlated with cell viability after stress imposition. The metabolomic profiles of these strains were compared before cell desiccation and after cell rehydration. In S. mikatae, the presence of lysine or glutamine during rehydration led to a 20% increase in survival whereas during dehydration the levels of both amino acids in this yeast were drastically reduced (AU)

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Membrane lipid variability in Saccharomyces cerevisiae wine strains rehydrated in the presence of metabolic activators.

Slight variations in lipid composition of wine yeast membranes can alter some essential functions including selective nutrient transport and ion permeability. The absence of oxygen during alcoholic fermentation inhibits fatty acid desaturation and sterol biosynthesis, thereby reducing the stress resistance of yeast cells. In this work, membrane lipids in two commercial active dry yeast strains rehydrated in the presence of three activators (ergosterol, tetrahydrofolic acid, and manganese) were studied. Each was assayed at three different concentrations. The effect of these activators on the phospholipid, neutral lipid, and fatty acid contents in cell membranes was assessed. Also, cell viability and fermentation kinetics were determined. Ergosterol was found to shorten the lag phase and improve cell viability and membrane lipid composition; tetrahydrofolic acid raised neutral lipid levels; and manganese(II) increased cell viability and modified phospholipid composition and linoleic acid concentration. All activators interacted with yeasts in a strain-dependent way.

Metabolomic charactetization of yeast cells after dehydration stress.

In this study, we analyzed the metabolite features of the yeasts Saccharomyces cerevisiae, Naumovia castellii, and Saccharomyces mikatae. The three species are closely related genetically but differ in their tolerance of desiccation stress. Specifically, we determined whether certain metabolites correlated with cell viability after stress imposition. The metabolomics profiles of these strains were compared before cell desiccation and after cell rehydration. In S. mikatae, the presence of lysine or glutamine during rehydration led to a 20% increase in survival whereas during dehydration the levels of both amino acids in this yeast were drastically reduced.

Effect of low temperature upon vitality of Saccharomyces cerevisiae phospholipid mutants.

The phospholipid metabolism of Saccharomyces cerevisiae plays a central role in its adaptation to low temperatures. In order to detect the key genes in this adaptation, various phospholipid mutants from the EUROSCARF collection of Saccharomyces cerevisiae BY4742 were tested to ascertain whether the suppression of some genes could improve the fermentation vitality of the cells at low temperature. The cell vitality and phospholipid composition of these mutants were analysed. Some knockouts improved (hmn1Δ) or impaired (cho2Δ and psd1Δ) their vitality at low temperature (13 ° C) but were not affected at optimum temperature (25 ° C). A common trait of the mutants that had some defect in vitality was a lower concentration of phosphatidylcholine and/or phosphatidylethanolamine. The supplementation with choline allowed them to recover viability, probably by synthesis through the Kennedy pathway. Hmn1Δ showed a lower concentration of phosphatidylcholine, which explains the dominant role of the de novo pathway in cellular phosphatidylethanolamine and phosphatidylcholine vs the Kennedy pathway. The absence of such genes as CRD1 or OPI3 produced important changes in phospholipid composition. Cardiolipin was not detected in crd1Δ but phosphatidylglycerol circumvents most of the functions assigned to CL. The considerable reduction in PC diminished the cell vitality of opi3Δ at both temperatures, although the decrease at 13 ° C was more marked.