Graca A.,University of Algarve |
Abadias M.,IRTA - Institute of Agricultural-Alimentary Research and Technology |
Salazar M.,Instituto Universitario |
Nunes C.,University of Algarve
Postharvest Biology and Technology | Year: 2011
Chlorine (sodium hypochlorite solution) is the most common disinfectant used in the fresh-cut industry, however, environmental and health risks related to its use have resulted in a need to find new sanitizers. Electrolyzed water (EW) is a promising alternative, showing a broad spectrum of microbial decontamination. In this study the efficacy of acidic electrolyzed water (AEW) and neutral electrolyzed water (NEW) as disinfectants of apple slices inoculated with Escherichia coli, Listeria innocua or Salmonella choleraesuis, individually or in a mixture, were compared to that of sodium hypochlorite solution and distilled water. Apple slices were inoculated with a 107cfu/mL suspension of the pathogens and treated with diluted electrolyzed water. Bactericidal activity of washing treatments was assessed after 30min and after storage for 5 days at 4°C. AEW and NEW disinfection efficacy was compared to that of washings with sodium hypochlorite at the same free chlorine concentration and with distilled water. AEW diluted to 100mg/L of free chlorine was the treatment with the highest bactericidal activity in all tested conditions (reductions obtained ranged from 1.2 to 2.4 log units) followed by NEW and AEW at 100 and 50mg/L of free chlorine respectively. In general these treatments were equal or more effective than sodium hypochlorite washings at 100mg/L of free chlorine. The effect of the different sanitizer washings when pathogens where in a mixture was similar to that which occurred when pathogens were individually inoculated. The effectiveness of all washings slightly decreased when apple slices were stored for 5 days at 4°C. © 2011 Elsevier B.V.
Soriano E.R.,Seccion Reumatologia |
Soriano E.R.,Instituto Universitario |
Soriano E.R.,Rheumatology Unit
Journal of Rheumatology | Year: 2012
Although several reviews and metaanalyses have shown lack of evidence of efficacy of traditional disease-modifying antirheumatic drugs (DMARD) in psoriatic arthritis (PsA), these drugs are very often used and are recommended by treatment guidelines around the world as first-line therapy for most patients with PsA. Some new investigations showed that higher doses of methotrexate (MTX) are more beneficial for patients with PsA with peripheral involvement. Also, observational studies have shown that retention of MTX for patients with PsA is comparable to that of patients with rheumatoid arthritis (RA), and that with MTX, remission is achievable by around 20% of patients with PsA. Sulfasalazine, leflunomide, and cyclosporine have also been shown to be effective in a small number of patients, although the overall effect on disease activity for these drugs is small. Although combination of anti-tumor necrosis factor agents with traditional DMARD is not mandatory in PsA as it is in RA, there is evidence that some extra benefit might be achieved when combinations are used, not only for the joints but for the skin. There is still room for the use of traditional DMARD in PsA, and for the time being, DMARD should still be considered as first-line therapy for most patients with PsA. The Journal of Rheumatology Copyright © 2012. All rights reserved.
Paula S.,Instituto Universitario |
Paula S.,Austral University of Chile
Global Ecology and Biogeography | Year: 2012
Aim To understand how vegetation mediates the interplay between fire and climate. Specifically, we predict that neither the switching of climatic conditions to high flammability nor the sensitivity of fire to such conditions are universal, but rather depend on fuel (vegetation) structure, which in turn changes with productivity. Location An aridity/productivity gradient on the Iberian Peninsula (Mediterranean Basin). Methods We defined 13 regions distributed along an aridity gradient, which thus differ in productivity and fuel structure. We then assessed the changes in the temporal fire-climate relationship across regions. Specifically, for each region we estimated three variables: the aridity level for switching to flammable conditions (i.e. climatic conditions conducive to fire), the frequency of these flammable conditions and the area burnt under such conditions. These variables were then related to regional aridity and fuel structure indicators. Results In mediterranean ecosystems, the aridity level for switching to flammable conditions increased along the aridity gradient. Differences in fire activity between regions were not explained by the frequency of flammable conditions but by the sensitivity of fire to such conditions, which was higher in wetter and more productive regions. Main conclusions Under mediterranean climatic conditions, fuel structure is more relevant in driving fire activity than the frequency of climatic conditions conducive to fire. At a global scale, fuel also drives the fire-climate relationship because it determines the climatic (aridity) threshold for switching to flammable conditions. Our results emphasize the role of landscape structure in shaping current and future fire-climate relationships at a regional scale, and suggest that future changes in the fire regime (i.e. under global warming) might be different from what it is predicted by climate alone. © 2012 Blackwell Publishing Ltd.
Newland M.J.,University of Birmingham |
Rickard A.R.,University of York |
Alam M.S.,University of Birmingham |
Vereecken L.,Max Planck Institute for Chemistry |
And 3 more authors.
Physical Chemistry Chemical Physics | Year: 2015
The removal of SO2 in the presence of alkene-ozone systems has been studied for ethene, cis-but-2-ene, trans-but-2-ene and 2,3-dimethyl-but-2-ene, as a function of humidity, under atmospheric boundary layer conditions. The SO2 removal displays a clear dependence on relative humidity for all four alkene-ozone systems confirming a significant reaction for stabilised Criegee intermediates (SCI) with H2O. The observed SO2 removal kinetics are consistent with relative rate constants, k(SCI + H2O)/k(SCI + SO2), of 3.3 (±1.1) × 10-5 for CH2OO, 26 (±10) × 10-5 for CH3CHOO derived from cis-but-2-ene, 33 (±10) × 10-5 for CH3CHOO derived from trans-but-2-ene, and 8.7 (±2.5) × 10-5 for (CH3)2COO derived from 2,3-dimethyl-but-2-ene. The relative rate constants for k(SCI decomposition)/k(SCI + SO2) are -2.3 (±3.5) × 1011 cm-3 for CH2OO, 13 (±43) × 1011 cm-3 for CH3CHOO derived from cis-but-2-ene, -14 (±31) × 1011 cm-3 for CH3CHOO derived from trans-but-2-ene and 63 (±14) × 1011 cm-3 for (CH3)2COO. Uncertainties are ±2σ and represent combined systematic and precision components. These values are derived following the approximation that a single SCI is present for each system; a more comprehensive interpretation, explicitly considering the differing reactivity for syn- and anti-SCI conformers, is also presented. This yields values of 3.5 (±3.1) × 10-4 for k(SCI + H2O)/k(SCI + SO2) of anti-CH3CHOO and 1.2 (±1.1) × 1013 for k(SCI decomposition)/k(SCI + SO2) of syn-CH3CHOO. The reaction of the water dimer with CH2OO is also considered, with a derived value for k(CH2OO + (H2O)2)/k(CH2OO + SO2) of 1.4 (±1.8) × 10-2. The observed SO2 removal rate constants, which technically represent upper limits, are consistent with decomposition being a significant, structure dependent, sink in the atmosphere for syn-SCI. © the Owner Societies 2015.
Borras E.,Instituto Universitario |
Tortajada-Genaro L.A.,Polytechnic University of Valencia
International Journal of Environmental Analytical Chemistry | Year: 2012
The determination of multifunctional oxygenated compounds in secondary organic aerosols (SOA) usually requires a derivatisation protocol prior to gas chromatography-mass spectrometry analysis (GC-MS). Our proposed protocol, a combination of O-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine (PFBHA) plus diluted N-methyl-N-trimethyl-silyltrifluoroacetamide (MSTFA) without catalyst, has improved the determination of carbonyls, polyhydroxyl-compounds, hydroxyl- carbonyls, hydroxyl-carboxylic acids and di-carboxylic acids. The optimised derivatisation protocol has been successfully used for blanks, standard mixtures and photo-oxidation products from isoprene and toluene generated in a high-volume simulation chamber (European Photoreactor, EUPHORE). Some previously identified degradation products for isoprene including tetrols such as threitol, erythritol; 2-methyltetrols and 2-methylglyceric acid; and for toluene including nitrophenols, methyl-nitrophenols, benzaldehyde, p-cresol, benzoic acid, glyoxylic acid and methyl-glyoxylic acid, have been identified in our aerosol samples, thus confirming the successful applicability of the proposed derivatisation protocol. Moreover, the reduction of artefacts and enhanced signal-to-noise ratio, have allowed us to extend the number of multifunctional compounds determined. These findings have demonstrated the validity of this analytical strategy, which will contribute to a better understanding of the atmospheric degradation chemistry of biogenic and anthropogenic pollutants. © 2012 Taylor & Francis.