485 research outputs found

    Removal of imidazolium- and pyridinium-based ionic liquids by Fenton oxidation

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    This is peer-post-review, pre-copyedit version of an article published in Environmental Science and Pollution Research. The final authenticated version is avilable online at: https://doi.org/10.1007/s11356-017-0867-4The oxidation of imidazolium (1-hexyl-3-methylimidazolium chloride, HmimCl) and pyridinium (1-butyl-4-methylpyridinium chloride, BmpyrCl) ionic liquids (ILs) by Fenton’s reagent has been studied. Complete conversion was achieved for both ILs using the stoichiometric H2O2dose at 70 °C, reaching final TOC conversion values around 45 and 55% for HmimCl and BmpyrCl, respectively. The decrease in hydrogen peroxide dose to substoichiometric concentrations (20–80% stoichiometric dose) caused a decrease in TOC conversion and COD removal and the appearance of hydroxylated oxidation by-products. Working at these substoichiometric H2O2doses allowed the depiction of a possible degradation pathway for the oxidation of both imidazolium and pyridinium ILs. The first step of the oxidation process consisted in the hydroxylation of the ionic liquid by the attack of the ·OH radicals, followed by the ring-opening and the formation of short-chain organic acids, which could be partially oxidized up to CO2and H2O. At H2O2doses near stoichiometric values (80%), the resulting effluents showed non-ecotoxic behaviour and more biodegradable character (BOD5/COD ratio around 0.38 and 0.58 for HmimCl and BmpyrCl, respectively) due to the formation of short-chain organic acids. [Figure not available: see fulltext.]The authors wish to thank the Spanish MINECO and Comunidad de Madrid for the financial support through the projects CTM2016-76564-R and S2013/MAE-2716, respectivel

    Comment on "Identifying Molecular Orientation of Individual C<sub>60</sub> on a Si(111)-(7x7) Surface"

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    A Comment on the Letter by J. G. Hou, et al., Phys. Rev. Lett. 83, 3001 (1999)

    VLA H53alpha observations of the central region of the Super Star Cluster Galaxy NGC 5253

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    We present observations in the H53alpha line and radio continuum at 43 GHz carried out with the VLA in the D array (2'' angular resolution) toward the starburst galaxy NGC 5253. VLA archival data have been reprocessed to produce a uniform set of 2, 1.3 and 0.7 cm high angular (0.''2 X 0.''1) radio continuum images. The RRL H53alpha, a previously reported measurement of the H92alpha RRL flux density and the reprocessed high angular resolution radio continuum flux densities have been modeled using a collection of HII regions. Based on the models, the ionized gas in the nuclear source has an electron density of ~6 X 10^4 cm^-3 and an volume filling factor of 0.05. A Lyman continuum photon production rate of 2 X 10^52 s^-1 is necessary to sustain the ionization in the nuclear region. The number of required O7 stars in the central 1.5 pc of the supernebula is ~ 2000. The H53alpha velocity gradient 10 km s^-1 arcsec^-1) implies a dynamical mass of ~3X10^5 Msun; this mass suggests the supernebula is confined by gravity.Comment: Accepted in Astrophysical Journal 7 figure

    Prognostic model for early acute rejection after liver transplantation

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    Hepatic graft rejection is a common complication after liver transplantation (LT), with a maximum incidence within the first weeks. The identification of high-risk patients for early acute rejection (EAR) might be useful for clinicians. A series of 133 liver graft recipients treated with calcineurin inhibitors was retrospectively assessed to identify predisposing factors for EAR and develop a mathematical model to predict the individual risk of each patient. The incidence of EAR (< or =45 days after LT) was 35.3%. Multivariate analysis showed that recipient age, underlying liver disease, and Child's class before LT were independently associated with the development of EAR. Combining these 3 variables, the following risk score for the development of EAR was obtained: EAR score [F(x)] = 2.44 + (1.14 x hepatitis C virus cirrhosis) + (2.78 x immunologic cirrhosis) + (2.51 x metabolic cirrhosis)--(0.08 x recipient age in years) + (1.65 x Child's class A) [corrected]. Risk for rejection = e(F(x))/1 + e(F(x)). The combination of age, cause of liver disease, and Child's class may allow us to predict the risk for EAR

    Liver transplantation in cirrhotic patients with diabetes mellitus: Midterm results, survival, and adverse events

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    Liver cirrhosis is frequently associated with diabetes mellitus (DM), and this metabolic complication is also frequent after orthotopic liver transplantation (OLT). The aim of our study is to investigate which factors are associated with DM before and after OLT and their impact on post-OLT evolution. We evaluated the prevalence of DM among 115 liver transplant candidates with cirrhosis and assessed their evolution after OLT (median follow-up, 41 months). Sixteen candidates had DM requiring pharmacological therapy (group A), 45 candidates had DM controlled with diet (group B), and 54 candidates did not have DM (group C). One-year and 3-year actuarial survival rates were 100% and 100% for group A, 91% and 85% for group B, and 77% and 74% for group C, respectively (P <.03). Post-OLT DM was more frequent in group A. The incidence of other metabolic complications, major infections, rejection, and arterial hypertension; the need for hospitalization; and renal and graft function of patients in groups A, B, and C were similar. The only risk factor for DM 1 year after OLT on multivariate analysis was pre-OLT DM requiring pharmacological treatment. The incidence of complications, need for hospitalization, and renal and graft function 1 year after OLT for patients with post-OLT DM were similar to those of patients without post-OLT DM. In conclusion, patients with cirrhosis who have DM have a greater risk for post-OLT DM, but their midterm survival is not worse than the survival of those without DM

    Readout electronics for the SiPM tracking plane in the NEXT-1 prototype

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    NEXT is a new experiment to search for neutrinoless double beta decay using a 100 kg radio-pure high-pressure gaseous xenon TPC with electroluminescence readout. A large-scale prototype with a SiPM tracking plane has been built. The primary electron paths can be reconstructed from time-resolved measurements of the light that arrives to the SiPM plane. Our approach is to measure how many photons have reached each SiPM sensor each microsecond with a gated integrator. We have designed and tested a 16-channel front-end board that includes the analog paths and a digital section. Each analog path consists of three different stages: a transimpedance amplifier, a gated integrator and an offset and gain control stage. Measurements show good linearity and the ability to detect single photoelectrons. © 2011 Elsevier B.V.The authors would like to acknowledge the support of the NEXT Collaboration, the DATE team at CERN PH-AID and the CONSOLIDER-INGENIO2010 grant CSD2008-0037 (Canfranc Underground Physics) from the Spanish Ministry of Science and Innovation.Herrero Bosch, V.; Toledo Alarcón, JF.; Català Pérez, JM.; Esteve Bosch, R.; Gil Ortiz, A.; Lorca, D.; Monzó Ferrer, JM.... (2012). Readout electronics for the SiPM tracking plane in the NEXT-1 prototype. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 695:229-232. https://doi.org/10.1016/j.nima.2011.12.057S22923269

    The structure of molecular gas associated with NGC2264: wide-field 12CO and H2 imaging

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    We present wide-field, high-resolution imaging observations in 12CO 3-2 and H2 1-0 S(1) towards a ~1 square degree region of NGC2264. We identify 46 H2 emission objects, of which 35 are new discoveries. We characterize several cores as protostellar, reducing the previously observed ratio of prestellar/protostellar cores in the NGC2264 clusters. The length of H2 jets increases the previously reported spatial extent of the clusters. In each cluster, <0.5% of cloud material has been perturbed by outflow activity. A principal component analysis of the 12CO data suggests that turbulence is driven on scales >2.6 pc, which is larger than the extent of the outflows. We obtain an exponent alpha=0.74 for the size-linewidth relation, possibly due to the high surface density of NGC2264. In this very active, mixed-mass star forming region, our observations suggest that protostellar outflow activity is not injecting energy and momentum on a large enough scale to be the dominant source of turbulence.Comment: MNRAS accepte

    Intrinsically regulated learning is modulated by synaptic dopamine signaling

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    We recently provided evidence that an intrinsic reward-related signal-triggered by successful learning in absence of any external feedback-modulated the entrance of new information into long-term memory via the activation of the dopaminergic midbrain, hippocampus, and ventral striatum (the SN/VTA-Hippocampal loop; Ripollés et al., 2016). Here, we used a double-blind, within-subject randomized pharmacological intervention to test whether this learning process is indeed dopamine-dependent. A group of healthy individuals completed three behavioral sessions of a language-learning task after the intake of different pharmacological treatments: a dopaminergic precursor, a dopamine receptor antagonist or a placebo. Results show that the pharmacological intervention modulated behavioral measures of both learning and pleasantness, inducing memory benefits after 24 hr only for those participants with a high sensitivity to reward. These results provide causal evidence for a dopamine-dependent mechanism instrumental in intrinsically regulated learning and further suggest that subject-specific reward sensitivity drastically alters learning success
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