463 research outputs found

    Electrochemical Activation of Ni Catalysts with Potassium Ionic Conductors for CO2 Hydrogenation

    Get PDF
    Three different kind of Ni-based catalysts were prepared on a K-β″Al2O3 solid electrolyte by combining the annealing of an organometallic paste and the addition of a catalyst powder. The different catalysts films were tested in the CO2 hydrogenation reaction under electrochemical promotion by K+ ions, and were characterized by XRD and SEM. The catalyst film derived from the addition of an α-Al2O3 powder to the Ni catalyst ink presented the highest catalytic activity as a result of the increase in Ni catalyst film porosity. The influence of the applied potential and other operation variables were evaluated on the Ni catalytic activity and selectivity. Hence, the CO production rate was enhanced either by decreasing the applied potential (with the consequent supply of K+ ions to the catalyst surface) or by increasing the CO2 (electron acceptor) feed concentration. On the other hand, CH4 production rate was favoured at positive potentials (removing K+ from the catalyst surface) or by increasing the H2 (electron donor) feed concentration. The global CO2 consumption rate increased upon negative polarization in all experiments and the electrochemical promotion of catalysis effect showed to be reversible and reproducible. Hence, the electrochemical promotion phenomena demonstrated to be a very useful technique to in situ modify and control the catalytic activity and selectivity of a non-noble metal such as Ni for the production of CH4 or syngas via CO2 valorization.Es la versión preprint del artículo. Se puede consultar la versión final en https://doi.org/10.1007/s11244-015-0488-

    Electropulsing effects on mechanical and metallurgical behavior of AISI-SAE 4140 steel

    Get PDF
    The electroplasticity phenomenon (EP) produces changes in the mechanical properties of a metal, due to the simultaneous application of mechanical stresses of compression, bending, etc., and high instantaneous current pulses. The changes produced on the plastic deformation rate by the EP are due to thermal effects (such as Joule effect) and other effects associated to the electric and magnetic fields. There are only a few studies that consider, as this paper does, the effects of electropulsing effect on tensile test processes in which the electron flow is esteemed as the main reason. In this paper, the results of a research on tensile test on specimen of AISI-SAE 4140, assisted by high-current-density electric pulses are presented. The aim is to evaluate the effect of these pulses on the microstructure and mechanical properties of metallic materials. The phase transformations and microstructural changes in the metallic specimens exposed to EP were analysed using Scanning Electron Microscopy (SEM), Diffraction Ray X (DRX) and Differential Scanning Calorimetry (DSC). Preliminary results show there are some differences in the material behaviour, between the specimens tensile tested with and without EP, such as: decreases values of yield and ultimate strength and XRD analyses attests to a slight displacement and intensity reduction of diffraction. Moreover, the application of current density in the order of 2.18 A/mm² is enough to produce changes in mechanical and metallographic properties of AISI/SAE 4140.Peer ReviewedPostprint (published version

    FAS system deregulation in T-cell lymphoblastic lymphoma

    Get PDF
    The acquisition of resistance towards FAS-mediated apoptosis may be required for tumor formation. Tumors from various histological origins exhibit FAS mutations, the most frequent being hematological malignancies. However, data regarding FAS mutations or FAS signaling alterations are still lacking in precursor T-cell lymphoblastic lymphomas (T-LBLs). The available data on acute lymphoblastic leukemia, of precursor origin as well, indicate a low frequency of FAS mutations but often report a serious reduction in FAS-mediated apoptosis as well as chemoresistance, thus suggesting the occurrence of mechanisms able to deregulate the FAS signaling pathway, different from FAS mutation. Our aim at this study was to determine whether FAS-mediated apoptotic signaling is compromised in human T-LBL samples and the mechanisms involved. This study on 26 T-LBL samples confirms that the FAS system is impaired to a wide extent in these tumors, with 57.7% of the cases presenting any alteration of the pathway. A variety of mechanisms seems to be involved in such alteration, in order of frequency the downregulation of FAS, the deregulation of other members of the pathway and the occurrence of mutations at FAS. Considering these results together, it seems plausible to think of a cumulative effect of several alterations in each T-LBL, which in turn may result in FAS/FASLG system deregulation. Since defective FAS signaling may render the T-LBL tumor cells resistant to apoptotic cell death, the correct prognosis, diagnosis and thus the success of anticancer therapy may require such an in-depth knowledge of the complete scenario of FAS-signaling alterations.S

    Planck 2015 results. XVI. Isotropy and statistics of the CMB

    Get PDF
    Cosmology (including clusters of galaxies).-- et al.We test the statistical isotropy and Gaussianity of the cosmic microwave background (CMB) anisotropies using observations made by the Planck satellite. Our results are based mainly on the full Planck mission for temperature, but also include some polarization measurements. In particular, we consider the CMB anisotropy maps derived from the multi-frequency Planck data by several component-separation methods. For the temperature anisotropies, we find excellent agreement between results based on these sky maps over both a very large fraction of the sky and a broad range of angular scales, establishing that potential foreground residuals do not affect our studies. Tests of skewness, kurtosis, multi-normality, N-point functions, and Minkowski functionals indicate consistency with Gaussianity, while a power deficit at large angular scales is manifested in several ways, for example low map variance. The results of a peak statistics analysis are consistent with the expectations of a Gaussian random field. The “Cold Spot” is detected with several methods, including map kurtosis, peak statistics, and mean temperature profile. We thoroughly probe the large-scale dipolar power asymmetry, detecting it with several independent tests, and address the subject of a posteriori correction. Tests of directionality suggest the presence of angular clustering from large to small scales, but at a significance that is dependent on the details of the approach. We perform the first examination of polarization data, finding the morphology of stacked peaks to be consistent with the expectations of statistically isotropic simulations. Where they overlap, these results are consistent with the Planck 2013 analysis based on the nominal mission data and provide our most thorough view of the statistics of the CMB fluctuations to date.The Planck Collaboration acknowledges the support of: ESA; CNES and CNRS/INSU-IN2P3-INP (France); ASI, CNR, and INAF (Italy); NASA and DoE (USA); STFC and UKSA (UK); CSIC, MINECO, JA, and RES (Spain); Tekes, AoF, and CSC (Finland); DLR and MPG (Germany); CSA (Canada); DTU Space (Denmark); SER/SSO (Switzerland); RCN (Norway); SFI (Ireland); FCT/MCTES (Portugal); ERC and PRACE (EU).Peer Reviewe

    FAS system deregulation in T-cell lymphoblastic lymphoma

    Get PDF
    The acquisition of resistance towards FAS-mediated apoptosis may be required for tumor formation. Tumors from various histological origins exhibit FAS mutations, the most frequent being hematological malignancies. However, data regarding FAS mutations or FAS signaling alterations are still lacking in precursor T-cell lymphoblastic lymphomas (T-LBLs). The available data on acute lymphoblastic leukemia, of precursor origin as well, indicate a low frequency of FAS mutations but often report a serious reduction in FAS-mediated apoptosis as well as chemoresistance, thus suggesting the occurrence of mechanisms able to deregulate the FAS signaling pathway, different from FAS mutation. Our aim at this study was to determine whether FAS-mediated apoptotic signaling is compromised in human T-LBL samples and the mechanisms involved. This study on 26 T-LBL samples confirms that the FAS system is impaired to a wide extent in these tumors, with 57.7% of the cases presenting any alteration of the pathway. A variety of mechanisms seems to be involved in such alteration, in order of frequency the downregulation of FAS, the deregulation of other members of the pathway and the occurrence of mutations at FAS. Considering these results together, it seems plausible to think of a cumulative effect of several alterations in each T-LBL, which in turn may result in FAS/FASLG system deregulation. Since defective FAS signaling may render the T-LBL tumor cells resistant to apoptotic cell death, the correct prognosis, diagnosis and thus the success of anticancer therapy may require such an in-depth knowledge of the complete scenario of FAS-signaling alterations.S

    Sigma-1 Receptor Agonism Promotes Mechanical Allodynia After Priming the Nociceptive System with Capsaicin.

    Get PDF
    Sigma-1 receptor antagonists promote antinociception in several models of pain, but the effects of sigma-1 agonists on nociception (particularly when the nociceptive system is primed) are not so well characterized; therefore we evaluated the effects of sigma-1 agonists on pain under different experimental conditions. The systemic administration of the selective sigma-1 agonists (+)-pentazocine and PRE-084, as well as the nonselective sigma-1 agonist carbetapentane (used clinically as an antitussive drug), did not alter sensitivity to mechanical stimulation under baseline conditions. However, they greatly promoted secondary mechanical allodynia after priming the nociceptive system with capsaicin. These effects of sigma-1 agonists were consistent in terms potency with the affinities of these drugs for sigma-1 receptors, were reversed by sigma-1 antagonists, and were not observed in sigma-1 knockout mice, indicating that they are sigma-1-mediated. Repeated systemic treatment with PRE-084 induced proallodynic effects even 24 h after treatment completion, but only after the nociceptive system was primed. However, neither the presence of this drug in the organism nor changes in sigma-1 receptor expression in areas involved in pain processing explains its long-term effects, suggesting that sustained sigma-1 agonism induces plastic changes in the nociceptive system that promote nociception

    Soluble epoxide hydrolase inhibitors: design, synthesis, in vitro profiling and in vivo evaluation in murine models of pain

    Get PDF
    Trabajo presentado en el ASPET Annual Meeting at Experimental Biology 2022, celebrado en Philadelphia, PA (Estados Unidos), del 2 al 5 de abril de 2022This research by the Grant PID2020-118127RB-I00 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe” to S.V. Financial support from Fundació Bosch i Gimpera, Universitat de Barcelona (F2I grant), to S.V., and from the Xunta de Galicia (ED431G 2019/02 and ED431C 2018/21) to M.I.L. are acknowledged. Partial support was provided by NIH-NIEHS River Award R35 ES03443, NIH-NIEHS Superfund Program P42 ES004699, NINDS R01 DK107767, and NIDDK R01 DK103616 to B.D.H. S.C. acknowledges a PhD fellowship from the Universitat de Barcelona (APIF grant)

    QUIJOTE scientific results-I. Measurements of the intensity and polarisation of the anomalous microwave emission in the Perseus molecular complex

    Get PDF
    et al.In this paper, we present Q-U-I JOint Tenerife Experiment (QUIJOTE) 10–20 GHz observations (194 h in total over ≈250 deg2) in intensity and polarisation of G159.6-18.5, one of the most widely studied regions harbouring anomalous microwave emission (AME). By combining with other publicly available intensity data, we achieve the most precise spectrum of the AME measured to date in an individual region, with 13 independent data points between 10 and 50 GHz being dominated by this emission. The four QUIJOTE data points provide the first independent confirmation of the downturn of the AME spectrum at low frequencies, initially unveiled by the COSMOlogical Structures On Medium Angular Scales experiment in this region. Our polarisation maps, which have an angular resolution of ≈1° and a sensitivity of ≈ 25 μK beam−1, are consistent with zero polarisation. We obtain upper limits on the polarisation fraction of Π < 6.3 and <2.8 per cent (95 per cent C.L.), respectively, at 12 and 18 GHz (ΠAME < 10.1 and <3.4 per cent with respect to the residual AME intensity), a frequency range where no AME polarisation observations have been reported to date. The combination of these constraints with those from other experiments confirm that all the magnetic dust models based on single-domain grains, and most of those considering randomly oriented magnetic inclusions, predict higher polarisation levels than is observed towards regions with AME. Also, neither of the two considered models of electric dipole emission seems to be compatible with all the observations together. More stringent constraints of the AME polarisation at 10–40 GHz are necessary to disentangle between different models, to which future QUIJOTE data will contribute.This work has been partially funded by the Spanish Ministry of Economy and Competitiveness (MINECO) under the projects AYA2007-68058-C03-01, AYA2010-21766-C03-02, AYA2012-39475-C02-01 and the Consolider-Ingenio project CSD2010-00064 (EPI: Exploring the Physics of Inflation). CD acknowledges support from an ERC Starting (Consolidator) Grant (no. 307209), SH from an STFC-funded studentship, and CHLC from the DIULS (Research Directorship of the University of La Serena).Peer Reviewe

    Prevención y gestión de residuos sólidos urbanos en el Valle de Mazatepec

    Get PDF
    En este periodo se trabajó fuertemente en la comunidad de Ahuisculco en colaboración con la asociación Selva Negra cuyos actores principales fueron: Lupita Zavala y René Velázquez, en donde se presentó la iniciativa de proyecto que habla sobre la gestión de residuos valorizables, el cual tuvo buen recibimiento por la comunidad y al presentarse al ejido se pudo conseguir una bodega que se planea utilizar a manera de centro comunitario de acopio de residuos sólidos urbanos; además de ello se consolidó una relación con la primaria Rafael Ramírez para la impartición de talleres y pláticas de educación ambiental, generando un plan de actividades autorizado por el Director Luis Cruz Alvarado y apoyado por la asociación Selva Negra. Este programa se plantea aplicar en el periodo de primavera 2022. A su vez, se trabajó en la comunidad de San Isidro Mazatepec donde se impartieron, diseñaron y gestionaron talleres de educación ambiental con los alumnos del COBAEJ con temas de compostaje, aprovechamiento de residuos, huertos en casa y colorantes naturales. También se organizó la rifa de un kit de separación de residuos orgánicos entre las comunidades de San Isidro y La Villita, con el objetivo de juntar fondos para poder remodelar e instalar puntos limpios en San Isidro y comenzar con la construcción de un punto de acopio de residuos en La Villita.ITESO, A.C

    Improved limits on the tensor-to-scalar ratio using BICEP and Planck data

    Get PDF
    We present constraints on the tensor-to-scalar ratio r using a combination of BICEP/Keck 2018 (BK18) and Planck PR4 data allowing us to fit for r consistently with the six parameters of the ? CDM model. We discuss the sensitivity of constraints on r to uncertainties in the ? CDM parameters as defined by the Planck data. In particular, we are able to derive a constraint on the reionization optical depth ? and thus propagate its uncertainty into the posterior distribution for r . While Planck sensitivity to r is slightly lower than the current ground-based measurements, the combination of Planck with BK18 and baryon-acoustic-oscillation data yields results consistent with r = 0 and tightens the constraint to r < 0.032 at 95% confidence.Planck is a project of the European Space Agency (ESA) with instruments provided by two scientific consortia funded by ESA member states and led by Principal Investigators from France and Italy, telescope reflectors provided through a collaboration between ESA and a scientific consortium led and funded by Denmark, and additional contributions from NASA (USA). We gratefully acknowledge support from the CNRS/IN2P3 Computing Center for providing computing and data-processing resources needed for this work. This research used resources of the National Energy Research Scientific Computing Center, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02- 05CH11231. Part of the research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (Grant No. 80NM0018D0004)
    corecore