485 research outputs found
Removal of imidazolium- and pyridinium-based ionic liquids by Fenton oxidation
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"
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
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
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
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
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
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
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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