303 research outputs found

    Object Distribution Networks for World-wide Document Circulation

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    This paper presents an Object Distribution System (ODS), a distributed system inspired by the ultra-large scale distribution models used in everyday life (e.g. food or newspapers distribution chains). Beyond traditional mechanisms of approaching information to readers (e.g. caching and mirroring), this system enables the publication, classification and subscription to volumes of objects (e.g. documents, events). Authors submit their contents to publication agents. Classification authorities provide classification schemes to classify objects. Readers subscribe to topics or authors, and retrieve contents from their local delivery agent (like a kiosk or library, with local copies of objects). Object distribution is an independent process where objects circulate asynchronously among distribution agents. ODS is designed to perform specially well in an increasingly populated, widespread and complex Internet jungle, using weak consistency replication by object distribution, asynchronous replication, and local access to objects by clients. ODS is based on two independent virtual networks, one dedicated to the distribution (replication) of objects and the other to calculate optimised distribution chains to be applied by the first network

    Ionic behavior assessment of surface-active compounds from corn steep liquor by exchange resins

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    Depending on their ionic nature, biosurfactants can be classified as nonionic, anionic, cationic, or amphoteric. The ionic behavior of biosurfactants is an important characteristic that dictates their use in industrial applications. In this work, a biosurfactant extract obtained from corn steep liquor was subjected to anionic or cationic resins, in order to study the ionic behavior under different operational conditions using response surface methodology. The independent variables included in the study are the dilution of biosurfactant solution, the amount of cationic or anionic resin, and the extraction time, whereas the dependent variables studied consisted of the surface tension of biosurfactant aqueous solution, after contacting with anionic or cationic resin. The results showed that biosurfactant extracted from corn steep liquor is amphoteric, since both resins were able to entrap this biosurfactant, making it particularly suited for use in personal care preparations for sensitive skin.Peer ReviewedPostprint (author's final draft

    Probabilistic trend detection in different levels of consciousness

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    We aimed to explore how alertness modulates the management of probabilistic information in order to accurately detect changing patterns in a stream of conflicting evidence. We hypothesized that a decreased level of alertness might disrupt the strategy deployed to approach a probabilistic reversal learning task by impairment of working memory, of integration and value-updating of each piece of evidence, and decreased cognitive control. Our results showed that performance in probabilistic reversal learning is altered in decreased alertness, in relation to a higher frequency of spontaneous switching between patterns. Besides, response time and type suggest an impaired ability to generate a stable evidence-based strategy, although evidence-driven responses are present even in heavy drowsiness

    Characterization of ionic nature of biosurfactant extracted from corn steep liquor using ionic exchange resins

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    [Excerpt] Resins have been used for years for the purification and characterization of ionic substances. The use of these resins allows not only remove impurities or increase the concentration of metabolites from industrial streams, but also allows define their ionic structure. In general, surfactants can be classified as non-ionic, anionic, cationic or amphoteric, what is going to define their future application at industrial scale. For example, anionic surfactants present the greatest wetting and emulsifying properties, while cationic ones have excellent antibacterial properties as well as good emulsifier capacities. Otherwise, amphoteric surfactants, which may have anionic or cationic properties depending on pH, are widely used in personal care products because of their less irritability to skin and eyes in comparison with other types of surfactants. [...]Spanish Ministry of Economy and Competitiveness (FEDER funds under the project CTM2015-68904)University of Vigo (Spain

    Adsorption capacity evaluation of a lipopeptide biosurfactant on human hair

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    [Excerpt] Nowadays, surfactants are used in a wide variety of applications in several fields, such as cosmetic and health care, environmental issues and, generally, as detergents. They present valuable characteristics since they can decrease water surface tension and solubilize molecules that cannot be eliminated in an aqueous media in normal conditions. Due to their surface active nature, synthetic surfactants can result toxic in the media in which they are applied. These drawbacks can be overcome by using biosurfactants, since they result environmentally friendly because of their biodegradability and low toxicity. Therefore, it would be interesting to replace synthetic detergents by biosurfactants in cosmetic and personal care formulations. From this point of view, Vecino et al., [1] have extracted biosurfactants from an industrial stream of corn wet milling industry, consisting of a lipopeptide that could have important applications in the formulation of natural shampoos. This biosurfactant is able to reduce the surface tension of water in more than 30 units. Thus, the aim of this work was to study the adsorption of this biosurfactant in human hair. [...]Spanish Ministry of Economy and Competitiveness (FEDER funds under the project CTM2015-68904University of Vigo (Spain

    Potential applications of biosurfactant extract obtained from corn steep liquor in hair formulations

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    [Excerpt] Biosurfactants (BS) have great advantages as an eco-friendly alternative to synthetic surfactants used in hair formulations. Human hair contains fatty acids (palmitic, palmitoleic, oleic and stearic acid) that prevent hair dryness and avoid the lower scalp hair density. These fatty acids are included in the composition of biosurfactant extract obtained from corn steep liquor (CSL) (Vecino et al., 2015). The adsorption of surfactants on hair depends on its ionic charge. Normally, hair surface has a negative charge, so it adsorbs cationic surfactants. For this reason, hair conditioners and also hair sunscreens contain cationic surfactants, mainly quaternary ammonium salts, which absorb UV light, protecting hair surface from dryness and oxidation. Contrarily, shampoo formulations are composed by anionic surface-active agents, which can induce, in many cases, hair protein loss, hair dryness, opacity and difficulty of handling. In order to know if biosurfactant extract, obtained from CSL, could be adsorbed on hair, its ionic behavior was evaluated by using anionic and cationic resins using a solid/liquid ratio of 1:10 at room temperature. After that, adsorption experiments using human hair were established at room temperature with hair/biosurfactant solution ratio of 1:50. [...]The financial support from the Spanish Ministry of Economy and Competitiveness (FEDER funds under the project CTM2015-68904) and L. Rodríguez-López is grateful for her predoctoral fellowship supported by the University of Vigo (Spain)

    Potential applications of multifunctional extract obtained from corn industry in food packaging

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    [Excerpt] Nowadays, in the food industry exists an increased demand, by the consumers, of natural additives that can replace those chemical additives obtained from non renewable resources. In this work extracts with surfactant and antioxidant properties were obtained from corn steep liquor (CSl) with potential applications in food packaging. the extraction process was carried out using ethyl acetate and the operational conditions consisted of: CSl/ethyl acetate 1:3 (v/v), at 25°C during 45 min with agitation system at 150 rpm. the antioxidant activity of the extract was determined by the dPPh (2,2-diphenyl-1-picrylhydrazyl) radical scavenging method; whereas the surface active properties was evaluated by the wilhelmy plate method in a force tensiometer with a platinum plate (easy dyne k20, kruSS gmbh), at room temperature. Fatty acid composition of extract was analyzed by gas chromatography coupled to a mass spectrometer (Bruker Scion 451-gC). [...

    Comparative study between biobased fatty acid extract obtained from corn steep liquor and "Tsubaki" extract

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    [Excerpt] "Tsubaki" is a Japanese camellia oil extract, which is rich in palmitic and linoleic (Omega-6) fatty acids, as well as contain numerous anti-aging polyphenol antioxidants. On the other hand, a bio-based surfactant composed by 64.2% of lipids and 21.9% of proteins can be extracted from corn steep liquor (CSL) following the methodology proposed by Vecino et al. (2015). The aim of this work was to compare some biochemical properties of "Tsubaki" fatty acid extract, included in high-end cosmetic formulations of different brans, and the biobased surfactant obtained from CSL, in terms of surface active capacity reduction as well as in terms of antioxidant activity and fatty acid composition. [...]The financial support from the Spanish Ministry of Economy and Competitiveness (FEDER funds under the project CTM2015-68904) and L. Rodríguez-López is grateful for her predoctoral fellowship supported by the University of Vigo (Spain)

    Essential oil-water emulsions containing a biosurfactant from Lactobacillus paracasei

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    [Excerpt] Surfactants play important roles in cosmetic products due to diverse properties including as emulsifier, foaming, wetting, detergency and solubilizer agents, among others. However, the market for beauty and personal care products based on natural ingredients has shown a relevant growth. In this sense, biosurfactants being non-toxic, biodegradable and ecofriendly natural compounds are suitable replacers of the chemical-based surfactants showing equal or better performances [1]. In addition, essential oils are natural ingredients extracted from plants that also are interesting ingredients for novel cosmetic formulations.The aim of this study was to formulate oil-water emulsions using a biosurfactant from Lactobacil/us paracasei in combination with several essential oils (wheat germ, almond, rosemary and jojoba oil). [...]Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BI0/04469/2013 unit, COMPETE 2020 (POCl-01-0145-FEDER-006684) and the project RECl/BBB-EBl/0179/2012 (FCOMP-01-0124-FEDER-027462
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