4,391 research outputs found

    M3 muscarinic acetylcholine receptor facilitates the endocytosis of mu opioid receptor mediated by morphine independently of the formation of heteromeric complexes

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    Morphine inefficiency to induce the internalization of mu opioid (MOP) receptors observed in numerous experimental models constitutes a paradigm of G-protein coupled receptor (GPCR) functional selectivity. We recently described that activation of Gαq/11 proteins through 5-HT2A serotonin receptors co-expressed in the same cells facilitates MOP receptor endocytosis promoted by morphine. In order to explore whether a different Gαq/11 coupled GPCR would emulate this effect, a double stable Flp-In T-REx HEK293 cell line permanently expressing MOP-YFP receptors along with FLAG-M3-Cerulean receptors expressed in an inducible manner was generated. Fluorescence microscopy examination of these cells revealed a co-distribution of both receptors mainly compartmentalized in plasma membrane. Concurrent stimulation with carbachol and morphine promoted MOP receptor internalization, desensitization and down-regulation and this facilitation was not dependent on PKC activation. Co-immunoprecipitation experiments demonstrated that FLAG-M3-Cerulean/MOP-YFP receptors interact forming heteromeric complexes in a time depending manner, i.e. the strongest interaction was detected after 96h of FLAG-M3-Cerulean induced expression. Under these experimental conditions, treatment of cells with carbachol plus morphine resulted in the internalization of both receptors within separated endocytic vesicles as visualized by confocal microscopy. This trafficking segregation observed for FLAG-M3-Cerulean and MOP-YFP receptors upon agonist stimulation suggests that this protein-protein interaction presents temporal and dynamic properties. Moreover, MOP-YFP receptor internalization facilitated by FLAG-M3-Cerulean receptors is independent of the constitution of heteromeric complexes. [Abstract copyright: Copyright © 2017. Published by Elsevier Inc.

    Energy reserves mobilization: Strategies of three decapod species

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    In food deprivation assays, several different responses have been observed in crustaceans. However, studying energy reserves utilization among more than one species during the same starvation period has not yet been performed, particularly to discern whether the responses are due to intrinsic and/or environmental factors. We hypothesize that decapod species with similar feeding habits have the same strategies in the use of energetic reserves during starvation, even though they inhabit different environments. The aim of this study was to compare the energy reserves mobilization of three decapods species (Cherax quadricarinatus, Palaemon argentinus and Munida gregaria) with similar feeding habits, exposed to similar food deprivation conditions. The crayfish, shrimp and squat-lobster were experimentally kept at continuous feeding or continuous starvation throughout 15 days. Every 3rd day, the midgut gland index (MGI), and the glycogen, lipid and protein contents were measured in the midgut gland (MG) and pleon muscle. Palaemon argentinus mobilized more reserves during starvation, followed by C. quadricarinatus, and the last M. gregaria. The starved shrimps presented low MGI, whereas MG showed a reduction in glycogen (from day 6 to 15), lipid (from day 3 to 15), and protein levels (at day 9 and 15) while in their muscle, lipid reserves decreased at days 3 and 6. In C. quadricarinatus, the most affected parameters in the MG were MGI, glycogen (from day 6 to 15), and lipids (at day 12 and 15). In the MG of M. gregaria only the glycogen was reduced during fasting from 3 to 15 days. Even though the three studied species have similar feeding habitats, we found that their energetic profile utilization is different and it could be explained by the habitat, life span, temperature, organ/tissue, and metabolism of the species. Our results may be useful to understand the several different responses of crustaceans during starvation.Fil: Sacristán, Hernán Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Rodriguez, Yamila Eliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Pereira, Nair de Los Angeles. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Lopez, Laura Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Lovrich, Gustavo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Fernandez Gimenez, Analia Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

    Optical design of inhomogeneous media to perfectly focus scalar wave fields

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    A method to design isotropic inhomogeneous refractive index distribution is presented, in which the scalar wave field solutions propagate exactly on an eikonal function (i.e., remaining constant on the Geometrical Optics wavefronts). This method is applied to the design of ¿dipole lenses¿, which perfectly focus a scalar wave field emitted from a point source onto a point absorber, in both two and three dimensions. Also, the Maxwell fish-eye lens in two and three dimensions analyzed

    Extreme super-resolution using the spherical geodesic waveguide

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    Leonhardt demonstrated (2009) that the 2D Maxwell Fish Eye lens (MFE) can focus perfectly 2D Helmholtz waves of arbitrary frequency, i.e., it can transport perfectly an outward (monopole) 2D Helmholtz wave field, generated by a point source, towards a "perfect point drain" located at the corresponding image point. Moreover, a prototype with λ/5 superresolution (SR) property for one microwave frequency has been manufactured and tested (Ma et al, 2010). Although this prototype has been loaded with an impedance different from the "perfect point drain", it has shown super-resolution property. However, neither software simulations nor experimental measurements for a broad band of frequencies have yet been reported. Here we present steady state simulations for two cases, using perfect drain as suggested by Leonhardt and without perfect drain as in the prototype. All the simulations have been done using a device equivalent to the MFE, called the Spherical Geodesic Waveguide (SGW). The results show the super-resolution up to λ/3000, for the system loaded with the perfect drain, and up to λ/500 for a not perfect load. In both cases super-resolution only happens for discrete number of frequencies. Out of these frequencies, the SGW does not show super-resolution in the analysis carried out

    Super-resolution Properties of the Maxwell Fish-Eyes

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    In this paper we present an analysis that shows the Maxwell Fish Eye (MFE) only has super-resolution property for some particular frequencies (for other frequencies, the MFE behaves as conventional imaging lens). These frequencies are directly connected with the Schumann resonance frequencies of spherical symmetric systems. The analysis have been done using a thin spherical waveguide (two concentric spheres with constant index between them), which is a dual form of the MFE (the electrical fields in the MFE can be mapped into the radial electrical fields in the spherical waveguide). In the spherical waveguide the fields are guided inside the space between the concentric spheres. A microwave circuit comprising three elements: the spherical waveguide, the source and the receiver (two coaxial cables) is designed in COMSOL. The super-resolution is demonstrated by calculation of Scaterring (S) parameters for different position of the coaxial cables and different frequencies of the input signal

    Perfect imaging of point sources with positive refraction

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    The capability of a device called the Spherical Geodesic Waveguide (SGW) to produce images with details below the classic Abbe diffraction limit (super-resolution) is analyzed here. The SGW is an optical system equivalent (by means of Transformation Optics) to the Maxwell Fish Eye (MFE) refractive index distribution. Recently, it has been claimed that the necessary condition to get super-resolution in the MFE and the SGW is the use of a Perfect Point Drain (PPD). The PPD is a punctual receptor placed in the focal point that absorbs the incident wave, without reflection or scattering. A microwave circuit comprising three elements, the SGW, the source and the drain (two coaxial lines loaded with specific impedances) is designed and simulated in COMSOL. The super-resolution properties have been analyzed for different position of the source and drain and for two different load impedances: the PPD and the characteristic line impedance. The results show that in both cases super-resolution occurs only for discrete number of frequencies. Out of these frequencies, the SGW does not show SR in the analysis carried out

    Gestión del Mantenimiento en EMZA

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    Control de los gastos en mantenimiento máquinas, instalaciones, y troqueles, además de los gastos derivados del taller de matricería y del consumo de aceites/lubricantes relacionados con el mantenimiento. Gestión de los mantenimientos preventivos, predictivos y correctivos en máquinas. Gestión de los mantenimientos preventivos, predictivos y correctivos en troqueles. Control de stocks de seguridad de elementos críticos de mantenimiento en troqueles. Elaboración de los formatos o registros codificados necesarios para la gestión del mantenimiento

    Super-resolution for a point source using positive refraction

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    Leonhardt demonstrated (2009) that the 2D Maxwell Fish Eye lens (MFE) can focus perfectly 2D Helmholtz waves of arbitrary frequency, i.e., it can transport perfectly an outward (monopole) 2D Helmholtz wave field, generated by a point source, towards a receptor called "perfect drain" (PD) located at the corresponding MFE image point. The PD has the property of absorbing the complete radiation without radiation or scattering and it has been claimed as necessary to obtain super-resolution (SR) in the MFE. However, a prototype using a "drain" different from the PD has shown λ/5 resolution for microwave frequencies (Ma et al, 2010). Recently, the SR properties of a device equivalent to the MFE, called the Spherical Geodesic Waveguide (SGW) (Miñano et al, 2012) have been analyzed. The reported results show resolution up to λ /3000, for the SGW loaded with the perfect drain, and up to λ /500 f for the SGW without perfect drain. The perfect drain was realized as a coaxial probe loaded with properly calculated impedance. The SGW provides SR only in a narrow band of frequencies close to the resonance Schumann frequencies. Here we analyze the SGW loaded with a small "perfect drain region" (González et al, 2011). This drain is designed as a region made of a material with complex permittivity. The comparative results show that there is no significant difference in the SR properties for both perfect drain designs

    Facile Surfactant-Assisted Synthesis of BiVO4 Nanoparticulate Films for Solar Water Splitting

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    Bismuth vanadate (BiVO4), which has attractive applicability as a photoactive material, presents applications that range from catalysis to water treatment upon visible light irradiation. In this study, we develop a simple synthesis of < 200 nm monoclinic BiVO4 nanoparticles, which were further deposited on transparent conductive substrates by spin coating and calcination, obtaining nanostructured films. The obtained nanostructured BiVO4 photoanodes were tested for water oxidation, leading to promising photocurrents exhibiting competitive onset potentials (~0.3 V vs. RHE). These nanoparticulate BiVO4 photoanodes represent a novel class of highly potential materials for the design of efficient photoelectrochemical devices
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