85 research outputs found

    Effects of Additives upon Percolation Temperature in AOT-Based Microemulsions

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    In the present review the percolative phenomena has been analyzed. Percolation is related to transport phenomena in microemulsions, in particular the electric charge transport. The influence of different additives upon electric percolation has been commented. The effects of the additives considered upon the microemulsion properties appear to come about through their association with the surfactant interface. The effects of these agents on the ease with which interdroplet channels allowing transfer of droplet contents are formed are not only responsible for their effects on percolation temperature, but also have serious implications for the rates of fast chemical reactions performed in microemulsions

    Influence of colloid suspensions of humic acids on the alkaline hydrolysis of N-methyl-N-nitroso-p-toluene sulfonamide

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    The influence of humic substances (HSs) upon the alkaline hydrolysis of N-methyl-N-nitroso-p-toluene sulfonamide has been studied. Important inhibition of hydrolysis reaction has been reported. This inhibition has been explained in terms of association of reactants to the humic substances. Kinetic results have been modeled using the micellar pseudophase model. © 2010 Wiley Periodicals, Inc.Fil: Astray, G.. Universidad de Vigo; EspañaFil: García Río, L.. Universidad de Santiago de Compostela; EspañaFil: Lodeiro, Anibal. Universidad de Vigo; EspañaFil: Mejuto, Juan Carlos. Universidad de Vigo; EspañaFil: Moldes, O.. Universidad de Vigo; EspañaFil: Morales, J.. Universidad de Vigo; EspañaFil: Moyano, Fernando. Universidad de Vigo; España. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; Argentin

    Materialistic cues make us miserable: A meta‐analysis of the experimental evidence for the effects of materialism on individual and societal well‐being

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    open access articleConsumer‐oriented societies are awash with materialistic messages that link happiness and success to wealth and consumption. However, despite extensive research evidence that dispositional materialistic orientations are correlated with lower well‐being, the effects of materialistic cues on the well‐being of individuals and social groups have not been examined. The present research meta‐analytically reviews the experimental evidence for the causal effects of materialism on two dimensions of well‐being: (a) individual and (b) societal. We included 27 independent studies that met the inclusion criteria of priming materialism and measuring well‐being (N = 3,649), containing a total of 62 effect sizes. Multilevel modeling revealed that materialism has an effect on both individual (ή = −0.39) and societal well‐being (ή = −0.41), suggesting that materialistic cues cause lower well‐being. Moderation effects suggested that materialistic cues might have a higher effect on interpersonal well‐being than on self‐evaluation indicators. We discuss the limitations of the current evidence, highlight the research gaps and underdeveloped areas, and provide recommendations such as minimum sample size for future experimental work, since the advancement of this area will help us to gain a better understanding of the impact of consumer‐oriented societies on the well‐being of individuals and social groups

    Forecast of the demand for hourly electric energy by artificial neural networks

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    Obtaining an accurate forecast of the energy demand is fundamental to support the several decision processes of the electricity service agents in a country. For market operators, a greater precision in the short-term load forecasting implies a more efficient programming of the electricity generation resources, which means a reduction in costs. In the long term, it constitutes a main indicator for the generation of investment signals for future installed capacity. This research proposes a prognostic model for the demand of electrical energy in Bogota, Colombia at hourly level in a full week, through Artificial Neural Network

    Study of pallial neurogenesis in shark embryos and the evolutionary origin of the subventricular zone

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    The dorsal part of the developing telencephalon is one of the brain areas that has suffered most drastic changes throughout vertebrate evolution. Its evolutionary increase in complexity was thought to be partly achieved by the appearance of a new neurogenic niche in the embryonic subventricular zone (SVZ). Here, a new kind of amplifying progenitors (basal progenitors) expressing Tbr2, undergo a second round of divisions, which is believed to have contributed to the expansion of the neocortex. Accordingly, the existence of a pallial SVZ has been classically considered exclusive of mammals. However, the lack of studies in ancient vertebrates precludes any clear conclusion about the evolutionary origin of the SVZ and the neurogenic mechanisms that rule pallial development. In this work, we explore pallial neurogenesis in a basal vertebrate, the shark Scyliorhinus canicula, through the study of the expression patterns of several neurogenic markers. We found that apical progenitors and radial migration are present in sharks, and therefore, their presence must be highly conserved throughout evolution. Surprisingly, we detected a subventricular band of ScTbr2-expressing cells, some of which also expressed mitotic markers, indicating that the existence of basal progenitors should be considered an ancestral condition rather than a novelty of mammals or amniotes. Finally, we report that the transcriptional program for the specification of glutamatergic pallial cells (Pax6, Tbr2, NeuroD, Tbr1) is also present in sharks. However, the segregation of these markers into different cell types is not clear yet, which may be linked to the lack of layering in anamniotesThis work was supported by the Spanish Ministerio de EconomĂ­a y Competitividad-FEDER (BFU2014-5863-1P)S

    The Effects of Overexpression of Histamine Releasing Factor (HRF) in a Transgenic Mouse Model

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    Asthma is a disease that affects all ages, races and ethnic groups. Its incidence is increasing both in Westernized countries and underdeveloped countries. It involves inflammation, genetics and environment and therefore, proteins that exacerbate the asthmatic, allergic phenotype are important. Our laboratory purified and cloned a histamine releasing factor (HRF) that was a complete stimulus for histamine and IL-4 secretion from a subpopulation of allergic donors' basophils. Throughout the course of studying HRF, it was uncovered that HRF enhances or primes histamine release and IL-13 production from all anti-IgE antibody stimulated basophils. In order to further delineate the biology of HRF, we generated a mouse model.We constructed an inducible transgenic mouse model with HRF targeted to lung epithelial cells, via the Clara cells. In antigen naĂŻve mice, overproduction of HRF yielded increases in BAL macrophages and statistical increases in mRNA levels for MCP-1 in the HRF transgenic mice compared to littermate controls. In addition to demonstrating intracellular HRF in the lung epithelial cells, we have also been able to document HRF's presence extracellularly in the BAL fluid of these transgenic mice. Furthermore, in the OVA challenged model, we show that HRF exacerbates the allergic, asthmatic responses. We found statistically significant increases in serum and BAL IgE, IL-4 protein and eosinophils in transgenic mice compared to controls.This mouse model demonstrates that HRF expression enhances allergic, asthmatic inflammation and can now be used as a tool to further dissect the biology of HRF

    Mesodermal fate decisions of a stem cell: the Wnt switch

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    Stem cells are a powerful resource for cell-based transplantation therapies in osteodegenerative disorders, but before some kinds of stem cells can be applied clinically, several aspects of their expansion and differentiation need to be better controlled. Wnt molecules and members of the Wnt signaling cascade have been ascribed a role in both these processes in vitro as well as normal development in vivo. However some results are controversial. In this review we will present the hypothesis that both canonical and non-canonical signaling are involved in mesenchymal cell fate regulation, such as adipogenesis, chondrogenesis and osteogenesis, and that in vitro it is a timely switch between the two that specifies the identity of the differentiating cell. We will specifically focus on the in vitro differentiation of adipocytes, chondrocytes and osteoblasts contrasting embryonic and mesenchymal stem cells as well as the role of Wnts in mesenchymal fate specification during embryogenesis
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