782 research outputs found

    Near edge x-ray absorption fine structure spectroscopy study of atomic nitrogen implanted in Al2O3 by low energy N2+ bombardment

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    N2+ bombardment of Al2O3 has been investigated by near edge x-ray absorption fine structure spectroscopy. Two kinds of species were detected and were attributed to implanted nitrogen atoms and nitride species. These results are discussed in relation to previous attributions in the literature of these species to AlNO and AlN.Comisión Interministerial de Ciencia y Tecnología (CICYT) MAT97-068

    Structural and chemical reactivity modifications of a cobalt perovskite induced by Sr-substitution. An in situ XAS study

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    LaCoO3 and La0.5Sr0.5CoO3-δ perovskites have been studied by in situ Co K-edge XAS. Although the partial substitution of La(III) by Sr(II) species induces an important increase in the catalytic oxidation activity and modifies the electronic state of the perovskite, no changes could be detected in the oxidation state of cobalt atoms. So, maintaining the electroneutrality of the perovskite requires the generation of oxygen vacancies in the network. The presence of these vacancies explains that the substituted perovskite is now much more reducible than the original LaCoO3 perovskite. As detected by in situ XAS, after a consecutive reduction and oxidation treatment, the original crystalline structure of the LaCoO3 perovskite is maintained, although in a more disordered state, which is not the case for the Sr doped perovskite. So, the La0.5Sr0.5CoO3-δ perovskite submitted to the same hydrogen reduction treatment produces metallic cobalt, while as determined by in situ XAS spectroscopy the subsequent oxidation treatment yields a Co(III) oxide phase with spinel structure. Surprisingly, no Co(II) species are detected in this new spinel phase.Ministerio de Ciencia y Educación ENE2011-2441

    Evaluation of a COTS 65-nm SRAM Under 15 MeV Protons and 14 MeV Neutrons at Low VDD

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    This article presents an experimental study on the sensitivity of a commercial-off-the-shelf (COTS) bulk 65-nm static random access memory (SRAM) under 15.6 MeV proton irradiation when powered up at ultralow bias voltage. Tests were run on standby and while reading the memory. Results show obvious evidence indicating that decreasing the bias voltage below 1 V exponentially increases the number of observed errors. Single-bit upsets (SBUs) and multiple-cell upsets (MCUs) (mostly with vertical shapes according to the manufacturers' layout) are reported and their behavior is analyzed in this article. Predictions on the single-event upset (SEU) sensitivity obtained with the multiscales single-event phenomena predictive platform (MUSCA-SEP3) modeling tool are also provided and compared with the experimental results. These are also compared with 14.2 MeV neutrons, showing a significant difference in the cross sections for both irradiation sources. Total ionizing dose (TID) tests and GEANT4 simulations were also run to check for the reason behind the difference in the cross section between these two particles

    Theory and practice: bulk synthesis of C3B and its H2- and Li-storage capacity.

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    Previous theoretical studies of C3B have suggested that boron-doped graphite is a promising H2- and Li-storage material, with large maximum capacities. These characteristics could lead to exciting applications as a lightweight H2-storage material for automotive engines and as an anode in a new generation of batteries. However, for these applications to be realized a synthetic route to bulk C3B must be developed. Here we show the thermolysis of a single-source precursor (1,3-(BBr2)2C6H4) to produce graphitic C3B, thus allowing the characteristics of this elusive material to be tested for the first time. C3B was found to be compositionally uniform but turbostratically disordered. Contrary to theoretical expectations, the H2- and Li-storage capacities are lower than anticipated, results that can partially be explained by the disordered nature of the material. This work suggests that to model the properties of graphitic materials more realistically, the possibility of disorder must be considered.We thank the ERC (Advance Investigator awards for D.S.W., C.P.G.), the EPSRC (T.C.K., P.D.M., H.G., J.C.), and the Spanish Ministerio de Economia y Competitividad (under grants ENE2011-24-412 and IPT-2011-1553-420000). We thank John Bulmer for Raman spectroscopy and Keith Parmenter for glass blowing. We thank the Schlumberger Gould Research Centre for XPS analysis.This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/anie.20141220

    Autologous intramyocardial injection of cultured skeletal muscle-derived stem cells in patients with non-acute myocardial infarction

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    AIM: Experimental animal studies suggest that the use of skeletal myoblast in patients with myocardial infarction may result in improved cardiac function. The aim of the study was to assess the feasibility and safety of this therapy in patients with myocardial infarction. METHODS AND RESULTS: Twelve patients with old myocardial infarction and ischaemic coronary artery disease underwent treatment with coronary artery bypass surgery and intramyocardial injection of autologous skeletal myoblasts obtained from a muscle biopsy of vastus lateralis and cultured with autologous serum for 3 weeks. Global and regional cardiac function was assessed by 2D and ABD echocardiogram. 18F-FDG and 13N-ammonia PET studies were used to determine perfusion and viability. Left ventricular ejection fraction (LVEF) improved from 35.5+/-2.3% before surgery to 53.5+/-4.98% at 3 months (P=0.002). Echocardiography revealed a marked improvement in regional contractility in those cardiac segments treated with skeletal myoblast (wall motion score index 2.64+/-0.13 at baseline vs 1.64+/-0.16 at 3 months P=0.0001). Quantitative 18F-FDG PET studies showed a significant (P=0.012) increased in cardiac viability in the infarct zone 3 months after surgery. No statistically significant differences were found in 13N-ammonia PET studies. Skeletal myoblast implant was not associated with an increase in adverse events. No cardiac arrhythmias were detected during early follow-up. CONCLUSIONS: In patients with old myocardial infarction, treatment with skeletal myoblast in conjunction with coronary artery bypass is safe and feasible and is associated with an increased global and regional left ventricular function,improvement in the viability of cardiac tissue in the infarct area and no induction of arrhythmias

    Effect of support oxygen storage capacity on the catalytic performance of Rh nanoparticles for CO2 reforming of methane

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    The effects of the metal oxide support on the activity, selectivity, resistance to carbon deposition and high temperature oxidative aging on the Rh-catalyzed dry reforming of methane (DRM) were investigated. Three Rh catalysts supported on oxides characterized by very different oxygen storage capacities and labilities (γ-Al 2O 3, alumina-ceria-zirconia (ACZ) and ceria-zirconia (CZ)) were studied in the temperature interval 400–750 °C under both integral and differential reaction conditions. ACZ and CZ promoted CO 2 conversion, yielding CO-enriched synthesis gas. Detailed characterization of these materials, including state of the art XPS measurements obtained via sample transfer between reaction cell and spectrometer chamber, provided clear insight into the factors that determine catalytic performance. The principal Rh species detected by post reaction XPS was Rh 0, its relative content decreasing in the order Rh/CZ(100%)>Rh/ACZ(72%)>Rh/γ-Al 2O 3(55%). The catalytic activity followed the same order, demonstrating unambiguously that Rh 0 is indeed the key active site. Moreover, the presence of CZ in the support served to maintain Rh in the metallic state and minimize carbon deposition under reaction conditions. Carbon deposition, low in all cases, increased in the order Rh/CZ < Rh/ACZ < Rh/γ-Al 2O 3 consistent with a bi-functional reaction mechanism whereby backspillover of labile lattice O 2− contributes to carbon oxidation, stabilization of Rh 0 and modification of its surface chemistry; the resulting O vacancies in the support providing centers for dissociative adsorption of CO 2. The lower apparent activation energy observed with CZ-containing samples suggests that CZ is a promising support component for use in low temperature DRM

    Intermediate Molecular Phenotypes to Identify Genetic Markers of Anthracycline-Induced Cardiotoxicity Risk.

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    Cardiotoxicity due to anthracyclines (CDA) affects cancer patients, but we cannot predict who may suffer from this complication. CDA is a complex trait with a polygenic component that is mainly unidentified. We propose that levels of intermediate molecular phenotypes (IMPs) in the myocardium associated with histopathological damage could explain CDA susceptibility, so variants of genes encoding these IMPs could identify patients susceptible to this complication. Thus, a genetically heterogeneous cohort of mice (n = 165) generated by backcrossing were treated with doxorubicin and docetaxel. We quantified heart fibrosis using an Ariol slide scanner and intramyocardial levels of IMPs using multiplex bead arrays and QPCR. We identified quantitative trait loci linked to IMPs (ipQTLs) and cdaQTLs via linkage analysis. In three cancer patient cohorts, CDA was quantified using echocardiography or Cardiac Magnetic Resonance. CDA behaves as a complex trait in the mouse cohort. IMP levels in the myocardium were associated with CDA. ipQTLs integrated into genetic models with cdaQTLs account for more CDA phenotypic variation than that explained by cda-QTLs alone. Allelic forms of genes encoding IMPs associated with CDA in mice, including AKT1, MAPK14, MAPK8, STAT3, CAS3, and TP53, are genetic determinants of CDA in patients. Two genetic risk scores for pediatric patients (n = 71) and women with breast cancer (n = 420) were generated using machine-learning Least Absolute Shrinkage and Selection Operator (LASSO) regression. Thus, IMPs associated with heart damage identify genetic markers of CDA risk, thereby allowing more personalized patient management.J.P.L.’s lab is sponsored by Grant PID2020-118527RB-I00 funded by MCIN/AEI/10.13039/ 501100011039; Grant PDC2021-121735-I00 funded by MCIN/AEI/10.13039/501100011039 and by the “European Union Next Generation EU/PRTR”, the Regional Government of Castile and León (CSI144P20). J.P.L. and P.L.S. are supported by the Carlos III Health Institute (PIE14/00066). AGN laboratory and human patients’ studies are supported by an ISCIII project grant (PI18/01242). The Human Genotyping unit is a member of CeGen, PRB3, and is supported by grant PT17/0019 of the PE I + D + i 2013–2016, funded by ISCIII and ERDF. SCLl is supported by MINECO/FEDER research grants (RTI2018-094130-B-100). CH was supported by the Department of Defense (DoD) BCRP, No. BC190820; and the National Cancer Institute (NCI) at the National Institutes of Health (NIH), No. R01CA184476. Lawrence Berkeley National Laboratory (LBNL) is a multi-program national laboratory operated by the University of California for the DOE under contract DE AC02-05CH11231. The Proteomics Unit belongs to ProteoRed, PRB3-ISCIII, supported by grant PT17/0019/0023 of the PE I + D +i, 2017–2020, funded by ISCIII and FEDER. RCC is funded by fellowships from the Spanish Regional Government of Castile and León. NGS is a recipient of an FPU fellowship (MINECO/FEDER). hiPSC-CM studies were funded in part by the “la Caixa” Banking Foundation under the project code HR18-00304 and a Severo Ochoa CNIC Intramural Project (Exp. 12-2016 IGP) to J.J.S

    MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

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    Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe

    Measurement of prompt open-charm production cross sections in proton-proton collisions at root s=13 TeV

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    The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb(-1). The differential production cross sections of the D*(+/-), D-+/-, and D-0 ((D) over bar (0)) mesons are presented in ranges of transverse momentum and pseudorapidity 4 < p(T) < 100 GeV and vertical bar eta vertical bar < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.Peer reviewe

    Measurement of B-c(2S)(+) and B-c*(2S)(+) cross section ratios in proton-proton collisions at root s=13 TeV

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