A novel HS-SBSE system coupled with gas chromatography and mass spectrometry for the analysis of organochlorine pesticides in water samples

A methodology to analyze organochlorine pesticides (OCPs) in water samples has been accomplished by using headspace stir bar sorptive extraction (HS-SBSE). The bars were in house coated with a thick film of PDMS in order to properly work in the headspace mode. Sampling was done by a novel HS-SBSE system whereas the analysis was performed by capillary GC coupled mass spectrometric detection (HS-SBSE-GC-MS). The extraction optimization, using different experimental parameters has been established by a standard equilibrium time of 120 min at 85 degrees C. A mixture of ACN/toluene as back extraction solvent promoted a good performance to remove the OCPs sorbed in the bar. Reproducibility between 2.1 and 14.8% and linearity between 0.96 and 1.0 were obtained for pesticides spiked in a linear range between 5 and 17 ng/g in water samples during the bar evaluation.

Analysis of dispersive and dissipative media with optical resonances

In this paper we analyze the problem of light-matter interaction when absorptive resonances are imbedded in the material dispersion. We apply an improved approach to aluminum (Al) in the optical frequency range to investigate the impact of these resonances on the operating characteristics of Al-based nanoscale devices. Quantities such as group velocity, stored energy density, and energy velocity, normally obtained using a single resonance model [Wave Propagation and Group Velocity (Academic Press, 1960), Nat. Mater. 11, 208 (2012)], are now accurately calculated regardless of the medium adopted. We adapt the Loudon approach [Nat. Mater. 11, 208 (2012)] to media with several optical resonances and present the details of the extended model. We also show pertinent results for Al-based metal-dielectric-metal (MDM) waveguides, around spectral resonances. The model delineated here can be applied readily to any metal accurately characterized by Drude-Lorentz spectral resonance features. (C) 2012 Optical Society of America

Gas-phase reactivity of 2-hydroxy-1,4-naphthoquinones: a computational and mass spectrometry study of lapachol congeners

In order to understand the influence of alkyl side chains on the gas-phase reactivity of 1,4-naphthoquinone derivatives, some 2-hydroxy-1,4-naphthoquinone derivatives have been prepared and studied by electrospray ionization tandem mass spectrometry in combination with computational quantum chemistry calculations. Protonation and deprotonation sites were suggested on the basis of gas-phase basicity, proton affinity, gas-phase acidity (?Gacid), atomic charges and frontier orbital analyses. The nature of the intramolecular interaction as well as of the hydrogen bond in the systems was investigated by the atoms-in-molecules theory and the natural bond orbital analysis. The results were compared with data published for lapachol (2-hydroxy-3-(3-methyl-2-butenyl)-1,4-naphthoquinone). For the protonated molecules, water elimination was verified to occur at lower proportion when compared with side chain elimination, as evidenced in earlier studies on lapachol. The side chain at position C(3) was found to play important roles in the fragmentation mechanisms of these compounds. Copyright (c) 2012 John Wiley & Sons, Ltd.

O estigma da esquizofrenia na mídia: um levantamento de notícias publicadas em veículos brasileiros de grande circulação

CONTEXTO: O estigma que pesa sobre as doenças psiquiátricas é o mais forte impedimento para que o paciente busque tratamento, mais até que a dificuldade de acesso aos serviços de saúde. A esquizofrenia também é a doença mais usada hoje como metáfora na mídia, aparecendo rotineiramente associada a crimes e violência. OBJETIVOS: Avaliação da presença do estigma estrutural na mídia brasileira por meio do levantamento de notícias em imprensa e internet que utilizam o termo "esquizofrenia" e correlatos ("esquizofrênico/a") sob três aspectos: (a) uso médico e científico; (b) atribuição do diagnóstico de esquizofrenia a suspeitos de crimes com pouco ou nenhum rigor médico ou científico; (c) uso metafórico. MÉTODOS: O estudo foi realizado em três etapas: levantamento de notícias, classificação dos itens encontrados e análise do contexto em que foram publicados. O levantamento foi realizado em dois períodos - 2008 e 2011 -, sendo o primeiro restrito ao jornal Folha de S. Paulo e o segundo ampliado para os portais dos principais veículos impressos brasileiros. RESULTADOS: Foram encontrados 229 textos, distribuídos da seguinte forma: 89 (39%) registros em ciência e saúde, com tendência à impessoalidade; 62 (27%) registros em crime e violência, em que o "diagnóstico" de esquizofrenia é feito por leigos e "corroborado" por uma arqueologia da vida do suspeito que arrola toda sorte de comportamentos fora de padrão; 78 (34%) de uso metafórico, sempre de caráter depreciativo. CONCLUSÕES: A maioria dos textos encontrados (a) não dá voz ao portador de esquizofrenia e a seu sofrimento, (b) banaliza a doença psiquiátrica ao empregá-la fora de contexto para caracterizar decisões políticas e econômicas contraditórias ou de caráter duvidoso e (c) reforça o estigma que pesa sobre o portador de esquizofrenia ao personalizá-lo apenas nos raros casos de violência em que se supõe seu diagnóstico.

Endophytic fungi from the Amazonian plant Paullinia cupana and from Olea europaea isolated using cassava as an alternative starch media source

Endophytic fungi live inside plants, apparently do not cause any harm to their hosts and may play important roles in defense and growth promotion. Fungal growth is a routine practice at microbiological laboratories, and the Potato Dextrose Agar (PDA) is the most frequently used medium because it is a rich source of starch. However, the production of potatoes in some regions of the world can be costly. Aiming the development of a new medium source to tropical countries, in the present study, we used leaves from the guarana (a tropical plant from the Amazon region) and the olive (which grows in subtropical and temperate regions) to isolate endophytic fungi using PDA and Manihot Dextrose Agar (MDA). Cassava (Manihot esculenta) was evaluated as a substitute starch source. For guarana, the endophytic incidence (EI) was 90% and 98% on PDA and MDA media, respectively, and 65% and 70% for olive, respectively. The fungal isolates were sequenced using the ITS- rDNA region. The fungal identification demonstrated that the isolates varied according to the host plant and media source. In the guarana plant, 13 fungal genera were found using MDA and six were found using PDA. In the olive plant, six genera were obtained using PDA and 4 were obtained using MDA. The multivariate analysis results demonstrated the highest fungal diversity from guarana when using MDA medium. Interestingly, some genera were isolated from one specific host or in one specific media, suggesting the importance of these two factors in fungal isolation specificity. Thus, this study indicated that cassava is a feasible starch source that could serve as a potential alternative medium to potato medium.