273 research outputs found

    Study of some citrus flavanones against zearalenone accumulation by Fusarium graminearum

    Get PDF
    Zearalenone (ZEA) is produced by Fusarium fungi in grains, in particular by Fusarium graminearum. ZEA is a non-steroidal estrogenic mycotoxin widely distributed. The flavanones naringin (NAR), hesperidin (HES) and neohesperidin (NEO) were extracted from citrus industry wastes, such as immature fruits, and tested against ZEA accumulation by F. graminearumin rice. Response Surace Methodology (RSM) was applied in order to optimize flavanones concentrations to achieve total ZEA reduction. Using this methodology, the optimal combinations obtained were HES -NAR: 0.232-0.299, HES-NEO: 0.400-0.001 and NAR-NEO: 0.423-0.001 mmol/kg rice in dry basis. However, NEO seems to have no effect on ZEA inhibition. When it is mixed with other flavanones, they need to be used in higher concentrations than when used alone. These theoretical concentrations obtained by RSM were assayed to verify the results, achieving total inhibition of ZEA accumulation in rice media. The use of the studied flavanones, obtained inexpensively from the residues of citrus industry, would tend to reduce food waste, improve profitability of these industries and diminish ZEA occurrence in rice.Fil: Pok, Paula Sol. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Salas, María Paula. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; ArgentinaFil: Resnik, Silvia Liliana. Fundación de Investigaciones Científicas "Teresa Benedicta de la Cruz"; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; ArgentinaFil: Pacin, A.. Fundación de Investigaciones Científicas "Teresa Benedicta de la Cruz"; ArgentinaFil: Munitz, Martín. Universidad Nacional de Entre Ríos; Argentin

    Solidification of Al-Sn-Cu based immiscible alloys under intense shearing

    Get PDF
    The official published version of the Article can be accessed from the link below - Copyright @ 2009 The Minerals, Metals & Materials Society and ASM InternationalThe growing importance of Al-Sn based alloys as materials for engineering applications necessitates the development of uniform microstructures with improved performance. Guided by the recently thermodynamically assessed Al-Sn-Cu system, two model immiscible alloys, Al-45Sn-10Cu and Al-20Sn-10Cu, were selected to investigate the effects of intensive melt shearing provided by the novel melt conditioning by advanced shear technology (MCAST) unit on the uniform dispersion of the soft Sn phase in a hard Al matrix. Our experimental results have confirmed that intensive melt shearing is an effective way to achieve fine and uniform dispersion of the soft phase without macro-demixing, and that such dispersed microstructure can be further refined in alloys with precipitation of the primary Al phase prior to the demixing reaction. In addition, it was found that melt shearing at 200 rpm and 60 seconds will be adequate to produce fine and uniform dispersion of the Sn phase, and that higher shearing speed and prolonged shearing time can only achieve minor further refinement.This work is funded by the EPSRC and DT

    Evolution of Th2 responses : Characterization of IL-4/13 in sea bass (Dicentrarchus labrax L.) and studies of expression and biological activity

    Get PDF
    Acknowledgements This research was funded by the European Commission under the 7th Framework Programme for Research and Technological Development (FP7) of the European Union (Grant Agreement 311993 TARGETFISH). T.W. received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland). MASTS is funded by the Scottish Funding Council (grant reference number HR09011) and contributing institutions.Peer reviewedPublisher PD

    Alternatively activated dendritic cells regulate CD4+ T-cell polarization in vitro and in vivo

    Get PDF
    Interleukin-4 is a cytokine widely known for its role in CD4(+) T cell polarization and its ability to alternatively activate macrophage populations. In contrast, the impact of IL-4 on the activation and function of dendritic cells (DCs) is poorly understood. We report here that DCs respond to IL-4 both in vitro and in vivo by expression of multiple alternative activation markers with a different expression pattern to that of macrophages. We further demonstrate a central role for DC IL-4Rα expression in the optimal induction of IFNγ responses in vivo in both Th1 and Th2 settings, through a feedback loop in which IL-4 promotes DC secretion of IL-12. Finally, we reveal a central role for RELMα during T-cell priming, establishing that its expression by DCs is critical for optimal IL-10 and IL-13 promotion in vitro and in vivo. Together, these data highlight the significant impact that IL-4 and RELMα can have on DC activation and function in the context of either bacterial or helminth pathogens

    Recycling the universe using scalar fields

    Get PDF
    We examine the behaviour of a closed oscillating universe filled with a homogeneous scalar field and find that, contrary to naive expectations, such a universe expands to larger volumes during successive expansion epochs. This intriguing behaviour introduces an arrow of time in a system which is time-reversible. The increase in the maximum size of the universe is closely related to the work done on/by the scalar field during one complete oscillatory cycle which, in turn, is related to the asymmetry in the scalar field equation of state during expansion and collapse. Our analysis shows that scalar fields with polynomial potentials V(ϕ)=λϕqV(\phi) = \lambda \phi^q, q>1q > 1 lead to a growing oscillation amplitude for the universe: the increase in amplitude between successive oscillations is more significant for smaller values of qq. Such behaviour allows for the effective recycling of the universe. A recycled universe can be quite old and can resolve the flatness problem. These results have strong bearing on cosmological models in which the role of dark matter is played by a scalar field. They are also relevant for chaotic inflationary models of the early universe since they demonstrate that, even if the universe fails to inflate the first time around, it will eventually do so during future oscillatory cycles. Thus, the space of initial conditions favourable for chaotic inflation increases significantly.Comment: 9 pages, 7 figures, accepted for publication in Phys. Rev.

    Metastable monotectic phase separation in Co–Cu alloys

    Get PDF
    The liquid phase separation behaviour of metastable monotectic Co–Cu alloys was investigated as a function of cooling rate using a 6.5 m drop-tube facility. A range of liquid phase separated morphologies were observed including stable two-layer core–shell, evolving core–shell and dendritic structures. It was found that in the core–shell structures the core was always in the higher melting point (Co-rich) phase, irrespective of the core and shell volume fraction. In Cu–50 at% Co alloy, high cooling rates were observed to yield two episodes of liquid phase separation, corresponding to binodal, followed by spinodal decomposition. The resulting structure comprised a core–shell structure in which the Co-rich core contained a very fine dispersion of Cu-rich particles with a Cu-rich shell which may, or may not, contain a similar dispersion of Co-rich particles
    corecore