123 research outputs found

    Method development for the analysis of volatile compounds in olive oil.

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    Olive oil consists mainly of triglycerides, in about 97 to 99% by weight. The minor compounds are a complex mixture of polar, apolar and amphiphilic substances, such as tocopherols, phenolic compounds, sterols, chlorophyll, carotenoids, terpene acids, monoglycerides and diglycerides, free fatty acids and volatile compounds. These volatiles are the compounds directly responsible for the aroma of the oil. Extra virgin olive oil has a complex aroma with more than 100 volatile compounds identified, among aldehydes, alcohols, esters, hydrocarbons, ketones and furans. The objective of this study was to develop an analytical method for volatile compounds in olive oils using solid-phase microextraction (SPME), gas chromatography coupled to mass spectrometry (GC-MS) and gas chromatography with flame ionization detection (GC-FID). For the SPME, different parameters like flask size (4, 10 and 20 mL), sampling temperatures (40 and 60 °C), headspace conditioning (10 and 60 min) and fiber exposure times (15 and 40 min) were tested. For GC analyses two different internal standards, methyl octanoate and tetradecane, were tested, as well as sub-ambient oven temperatures with liquid nitrogen. A 1 g of sample and a divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PMDS) fiber were used in all the tests. Analytical curves from the FID data were constructed for linearity evaluation, whereas internal standard was used for quantification ofcompounds such as 3-hexenol, 2-hexanal and limonene. Identification was performed based on mass spectra, co-injection of standards and retention indices data. The best conditions for SPME analysis were sample temperature of 40 °C, 10 min of headspace conditioning and fiber exposure for 40 min, in a 4 mL flask. For the chromatographic analyzes, tetradecane was chosen as the internal standard. Oven temperature program with cryofocusing led to a much better separation and, therefore, better quantitation and identification of the morevolatile compounds.De 15 a 16 maio 2019. Trabalhos apresentados de forma oral

    Integrated Modelling Frameworks for Environmental Assessment and Decision Support

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    As argued in Chapter 1, modern management of environmental resources defines problems from a holistic and integrated perspective, thereby imposing strong requirements on Environmental Decision Support Systems (EDSSs) and Integrated Assessment Tools (IATs). These systems and tools tend to be increasingly complex in terms of software architecture and computational power in order to cope with the type of problems they must solve. For instance, the discipline of Integrated Assessment (IA) needs tools that arc able to span a wide range of disciplines, from socio-economics to ecology to hydrology. Such tools must support a wide range of methodologies and techniques like agent-based modeling, Bayesian decision networks, optimization, multicriteria analyses and visualization tools, to name a few

    Evaluation of the genetic diversity of Histoplasma capsulatum var. capsulatum isolates from north-eastern Brazil

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    Since the beginning of the HIV epidemic, there has been a significant increase in the number of histoplasmosis cases in Ceara, a state in north-east Brazil. The lack of epidemiological data on the genotypes circulating in the north-east region shows the importance of more detailed studies on the molecular epidemiology of Histoplasma capsulatum var. capsulatum in this region. Different molecular techniques have been used to better characterize the genetic profile of H. capsulatum var. capsulatum strains. The aim of this study was to analyse the genetic diversity of H. capsulatum var. capsulatum isolates in Fortaleza, the capital of Ceara, through the sequencing of the internal transcribed spacer (ITS)1-5.8S-ITS2 region, and establish the molecular profile of these isolates, along with strains from south-east Brazil, by RAPD analysis, featuring the different clusters in those regions. The isolates were grouped into two clusters. Cluster 1 included strains from the south-east and north-east regions with separation of isolates into three distinct subgroups (subgroups 1a, 1 b and 1 c). Cluster 2 included only samples from north-east Brazil. Sequencing of the ITS1 -5.8S-ITS2 region allowed the detection of two major clades, which showed geographical correlation between them and their subgroups. Therefore, it can be concluded that the H. capsulatum var. capsulatum isolates from Ceara have a high degree of genetic polymorphism. The molecular data also confirm that populations of this fungus are composed of different genotypes in Brazil and worldwide.National Council for Scientific and Technological Development (CNPq)[562296/2010-7, 552161/2011-0, 304779/2011-3, 473025/2012-4]Brazilian Federal Agency for the Support and Evaluation of Graduate Education (CAPES) [2103/2009

    Multicenter, International Study of MIC/MEC Distributions for Definition of Epidemiological Cutoff Values for Sporothrix Species Identified by Molecular Methods

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    ABSTRACT Clinical and Laboratory Standards Institute (CLSI) conditions for testing the susceptibilities of pathogenic Sporothrix species to antifungal agents are based on a collaborative study that evaluated five clinically relevant isolates of Sporothrix schenckii sensu lato and some antifungal agents. With the advent of molecular identification, there are two basic needs: to confirm the suitability of these testing conditions for all agents and Sporothrix species and to establish species-specific epidemiologic cutoff values (ECVs) or breakpoints (BPs) for the species. We collected available CLSI MICs/minimal effective concentrations (MECs) of amphotericin B, five triazoles, terbinafine, flucytosine, and caspofungin for 301 Sporothrix schenckii sensu stricto, 486 S. brasiliensis, 75S. globosa, and 13 S. mexicana molecularly identified isolates. Data were obtained in 17 independent laboratories (Australia, Europe, India, South Africa, and South and North America) using conidial inoculum suspensions and 48 to 72 h of incubation at 35°C. Sufficient and suitable data (modal MICs within 2-fold concentrations) allowed the proposal of the following ECVs for S. schenckii and S. brasiliensis, respectively: amphotericin B, 4 and 4 g/ml; itraconazole, 2 and 2 g/ml; posaconazole, 2 and 2 g/ml; and voriconazole, 64 and 32 g/ml. Ketoconazole and terbinafine ECVs for S. brasiliensis were 2 and 0.12 g/ml, respectively. Insufficient or unsuitable data precluded the calculation of ketoconazole and terbinafine (or any other antifungal agent) ECVs for S. schenckii, as well as ECVs for S. globosa and S. mexicana. These ECVs could aid the clinician in identifying potentially resistant isolates (non-wild type) less likely to respond to therapy

    Rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART): study protocol for a randomized controlled trial

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    BACKGROUND: Acute respiratory distress syndrome (ARDS) is associated with high in-hospital mortality. Alveolar recruitment followed by ventilation at optimal titrated PEEP may reduce ventilator-induced lung injury and improve oxygenation in patients with ARDS, but the effects on mortality and other clinical outcomes remain unknown. This article reports the rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART). METHODS/DESIGN: ART is a pragmatic, multicenter, randomized (concealed), controlled trial, which aims to determine if maximum stepwise alveolar recruitment associated with PEEP titration is able to increase 28-day survival in patients with ARDS compared to conventional treatment (ARDSNet strategy). We will enroll adult patients with ARDS of less than 72 h duration. The intervention group will receive an alveolar recruitment maneuver, with stepwise increases of PEEP achieving 45 cmH2O and peak pressure of 60 cmH2O, followed by ventilation with optimal PEEP titrated according to the static compliance of the respiratory system. In the control group, mechanical ventilation will follow a conventional protocol (ARDSNet). In both groups, we will use controlled volume mode with low tidal volumes (4 to 6 mL/kg of predicted body weight) and targeting plateau pressure 6430 cmH2O. The primary outcome is 28-day survival, and the secondary outcomes are: length of ICU stay; length of hospital stay; pneumothorax requiring chest tube during first 7 days; barotrauma during first 7 days; mechanical ventilation-free days from days 1 to 28; ICU, in-hospital, and 6-month survival. ART is an event-guided trial planned to last until 520 events (deaths within 28 days) are observed. These events allow detection of a hazard ratio of 0.75, with 90% power and two-tailed type I error of 5%. All analysis will follow the intention-to-treat principle. DISCUSSION: If the ART strategy with maximum recruitment and PEEP titration improves 28-day survival, this will represent a notable advance to the care of ARDS patients. Conversely, if the ART strategy is similar or inferior to the current evidence-based strategy (ARDSNet), this should also change current practice as many institutions routinely employ recruitment maneuvers and set PEEP levels according to some titration metho
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