117 research outputs found

    Coatings from different sources for postharvest conservation of mango fruit cv Palmer

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    The aim of this study was to select edible coatings from different sources, as cassava starch, carboxymethyl cellulose (CMC), chitosan, Aloe veto, beeswax and sodium alginate, including some additives, which enable improved quality and postharvest conservation on 'Palmer' mango fruit, stored under refrigeration followed by room temperature

    Effect of the Antioxidant Lipoic Acid in Aortic Phenotype in a Marfan Syndrome Mouse Model

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    Marfan syndrome (MFS) cardiovascular manifestations such as aortic aneurysms and cardiomyopathy carry substantial morbidity/mortality. We investigated the effects of lipoic acid, an antioxidant, on ROS production and aortic remodeling in a MFS mgΔloxPneo mouse model. MFS and WT (wild-type) 1-month-old mice were allocated to 3 groups: untreated, treated with losartan, and treated with lipoic acid. At 6 months old, echocardiography, ROS production, and morphological analysis of aortas were performed. Aortic ROS generation in 6-month-old MFS animals was higher at advanced stages of disease in MFS. An unprecedented finding in MFS mice analyzed by OCT was the occurrence of focal inhomogeneous regions in the aortic arch, either collagen-rich extremely thickened or collagen-poor hypotrophic regions. MFS animals treated with lipoic acid showed markedly reduced ROS production and lower ERK1/2 phosphorylation; meanwhile, aortic dilation and elastic fiber breakdown were unaltered. Of note, lipoic acid treatment associated with the absence of focal inhomogeneous regions in MFS animals. Losartan reduced aortic dilation and elastic fiber breakdown despite no change in ROS generation. In conclusion, oxidant generation by itself seems neutral with respect to aneurysm progression in MFS; however, lipoic acid-mediated reduction of inhomogeneous regions may potentially associate with less anisotropy and reduced chance of dissection/rupture

    Corrosion behaviour of porous Ti intended for biomedical applications

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    Porous Ti implants are being developed inorder to reduce the biomechanical mismatch between theimplant and the bone, as well as increasing the osseointegrationby improving the bone in-growth. Most of the focusin the literature has been on the structural, biological andmechanical characterization of porous Ti whereas there islimited information on the electrochemical characterization.Therefore, the present work aims to study the corrosionbehaviour of porous Ti having 30 and 50 % ofnominal porosity, produced by powder metallurgy routeusing the space holder technique. The percentage, size anddistribution of the pores were determined by image analysis.Electrochemical tests consisting of potentiodynamicpolarization and electrochemical impedance spectroscopywere performed in 9 g/L NaCl solution at body temperature.Electrochemical studies revealed that samples presenteda less stable oxide film at increased porosity, morespecifically, the complex geometry and the interconnectivityof the pores resulted in formation of less protectiveoxide film in the pores.This study was supported by FCT with the reference project UID/EEA/04436/2013, by FEDER funds through the COMPETE 2020 – Programa Operacional Competitividade e Internacionalizac¸a˜o (POCI) with the reference project POCI-01-0145- FEDER-006941, Programa de Acc¸o˜es Universita´rias Integradas LusoFrancesas’ (PAUILF TC-12_14), and The Calouste Gulbenkian Foundation through ‘‘Programa de Mobilidade Acade´mica para Professores’’. The authors would also like to acknowledge Prof. Ana Senos (University of Aveiro) and Prof. Jose´ Carlos Teixeira (University of Minho) for the provision of the characterization facilities.info:eu-repo/semantics/publishedVersio

    Blood Meal-Derived Heme Decreases ROS Levels in the Midgut of Aedes aegypti and Allows Proliferation of Intestinal Microbiota

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    The presence of bacteria in the midgut of mosquitoes antagonizes infectious agents, such as Dengue and Plasmodium, acting as a negative factor in the vectorial competence of the mosquito. Therefore, knowledge of the molecular mechanisms involved in the control of midgut microbiota could help in the development of new tools to reduce transmission. We hypothesized that toxic reactive oxygen species (ROS) generated by epithelial cells control bacterial growth in the midgut of Aedes aegypti, the vector of Yellow fever and Dengue viruses. We show that ROS are continuously present in the midgut of sugar-fed (SF) mosquitoes and a blood-meal immediately decreased ROS through a mechanism involving heme-mediated activation of PKC. This event occurred in parallel with an expansion of gut bacteria. Treatment of sugar-fed mosquitoes with increased concentrations of heme led to a dose dependent decrease in ROS levels and a consequent increase in midgut endogenous bacteria. In addition, gene silencing of dual oxidase (Duox) reduced ROS levels and also increased gut flora. Using a model of bacterial oral infection in the gut, we show that the absence of ROS resulted in decreased mosquito resistance to infection, increased midgut epithelial damage, transcriptional modulation of immune-related genes and mortality. As heme is a pro-oxidant molecule released in large amounts upon hemoglobin degradation, oxidative killing of bacteria in the gut would represent a burden to the insect, thereby creating an extra oxidative challenge to the mosquito. We propose that a controlled decrease in ROS levels in the midgut of Aedes aegypti is an adaptation to compensate for the ingestion of heme
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