782 research outputs found

    Cation-swapped homogeneous nanoparticles in perovskite oxides for high power density

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    Exsolution has been intensively studied in the fields of energy conversion and storage as a method for the preparation of catalytically active and durable metal nanoparticles. Under typical conditions, however, only a limited number of nanoparticles can be exsolved from the host oxides. Herein, we report the preparation of catalytic nanoparticles by selective exsolution through topotactic ion exchange, where deposited Fe guest cations can be exchanged with Co host cations in PrBaMn1.7Co0.3O5+delta. Interestingly, this phenomenon spontaneously yields the host PrBaMn1.7Fe0.3O5+delta, liberating all the Co cations from the host owing to the favorable incorporation energy of Fe into the lattice of the parent host (Delta E-incorporation = -0.41 eV) and the cation exchange energy (Delta E-exchange = -0.34 eV). Remarkably, the increase in the number of exsolved nanoparticles leads to their improved catalytic activity as a solid oxide fuel cell electrode and in the dry reforming of methane

    Predictive power of the ADHD GWAS 2019 polygenic risk scores in independent samples of bipolar patients with childhood ADHD

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    BACKGROUND Although there is evidence of genetic correlation between bipolar disorder (BP) and ADHD, the extent of the shared genetic risk and whether childhood ADHD (cADHD) influences the characteristics of the adult BP remain unclear. Our objectives were: (i) to test the ability of polygenic risk scores (PRS) derived from the latest PGC ADHD-GWAS (Demontis et al., 2019) to predict the presence of cADHD in BP patients; (ii) to examine the hypothesis that BP preceded by cADHD is a BP subtype with particular clinical traits and (iii) partially shares its molecular basis with ADHD. METHOD PRS derived from the ADHD-GWAS-2019 were tested in BP patients (N = 942) assessed for cADHD with the Wender Utah Rating Scale and in controls from Romania and UK (N = 1616). RESULTS The ADHD-PRS differentiated BP cases with cADHD from controls. Proband sex and BP age-of-onset significantly influenced the discriminative power of the ADHD-PRS. The ADHD-PRS predicted the cADHD score only in males and in BP cases with early age-of-onset (≤21 years). Bipolar patients with cADHD had a younger age-of-onset of mania/depression than patients without cADHD. The ADHD-PRS predicted the BP-affection status in the comparison of early-onset BP cases with controls suggesting a partial molecular overlap between early-onset BP and ADHD. LIMITATIONS Retrospective diagnosis of cADHD, small sample size. CONCLUSIONS The PRS-analysis indicated an acceptable predictive ability of the ADHD-SNP-set 2019 in independent BP samples. The best prediction of both cADHD and BP-affection status was found in the early-onset BP cases. The results may have impact on the individual disease monitoring

    Plasma Driven Exsolution for Nanoscale Functionalization of Perovskite Oxides

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    Perovskite oxides with dispersed nanoparticles on their surface are considered instrumental in energy conversion and catalytic processes. Redox exsolution is an alternative method to the conventional deposition techniques for directly growing well-dispersed and anchored nanoarchitectures from the oxide support through thermochemical or electrochemical reduction. Herein, a new method for such nanoparticle nucleation through the exposure of the host perovskite to plasma is shown. The applicability of this new method is demonstrated by performing catalytic tests for CO2 hydrogenation over Ni exsolved nanoparticles prepared by either plasma or conventional H2 reduction. Compared to the conventional thermochemical H2 reduction, there are plasma conditions that lead to the exsolution of a more than ten times higher Ni amount from a lanthanum titanate perovskite, which is similar to the reported values of the electrochemical method. Unlike the electrochemical method, however, plasma does not require the integration of the material in an electrochemical cell, and is thus applicable to a wide range of microstructures and physical forms. Additionally, when N2 plasma is employed, the nitrogen species are stripping out oxygen from the perovskite lattice, generating a key chemical intermediate, such as NO, rendering this technology even more appealing.</p

    Measurement of shower development and its Moli\`ere radius with a four-plane LumiCal test set-up

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    A prototype of a luminometer, designed for a future e+e- collider detector, and consisting at present of a four-plane module, was tested in the CERN PS accelerator T9 beam. The objective of this beam test was to demonstrate a multi-plane tungsten/silicon operation, to study the development of the electromagnetic shower and to compare it with MC simulations. The Moli\`ere radius has been determined to be 24.0 +/- 0.6 (stat.) +/- 1.5 (syst.) mm using a parametrization of the shower shape. Very good agreement was found between data and a detailed Geant4 simulation.Comment: Paper published in Eur. Phys. J., includes 25 figures and 3 Table

    An expression atlas of chemosensory ionotropic glutamate receptors identifies a molecular basis of carbonation detection

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    Taste perception is thought to involve the encoding of appetitive and aversive chemical cues in food through a limited number of sensory pathways. Through expression analysis of the complete repertoire of Drosophila Ionotropic Receptors (IRs), a sensory subfamily of ionotropic glutamate receptors, we reveal that the majority of IRs is expressed in diverse peripheral neuron populations across gustatory organs in both larvae and adults, implying numerous roles in taste-evoked behaviours. We characterise Ir56d, which labels two anatomically-distinct classes of neurons in the proboscis: one represents a subset of sugar- and fatty acid-sensing neurons, while the other responds to carbonated solutions and fatty acids. Mutational analysis shows that IR56d, together with the broadly-expressed co-receptors IR25a and IR76b, is essential for physiological activation by carbonation and fatty acids, but not sucrose. We further demonstrate that carbonation is behaviourally attractive to flies (in an IR56d-dependent manner), but in a distinct way to other appetitive stimuli. Our work provides a valuable toolkit for investigating the taste functions of IRs, defines a molecular basis of carbonation sensing, and illustrates how the gustatory system uses combinatorial expression of sensory receptors in distinct neuron types to coordinate behaviour

    A Mechanistic and Pathophysiological Approach for Stroke Associated with Drugs of Abuse

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    Drugs of abuse are associated with stroke, especially in young individuals. The major classes of drugs linked to stroke are cocaine, amphetamines, heroin, morphine, cannabis, and new synthetic cannabinoids, along with androgenic anabolic steroids (AASs). Both ischemic and hemorrhagic stroke have been reported due to drug abuse. Several common mechanisms have been identified, such as arrhythmias and cardioembolism, hypoxia, vascular toxicity, vascular spasm and effects on the thrombotic mechanism, as causes for ischemic stroke. For hemorrhagic stroke, acute hypertension, aneurysm formation/rupture and angiitis-like changes have been implicated. In AAS abuse, the effect of blood pressure is rather substance specific, whereas increased erythropoiesis usually leads to thromboembolism. Transient vasospasm, caused by synthetic cannabinoids, could lead to ischemic stroke. Opiates often cause infective endocarditis, resulting in ischemic stroke and hypereosinophilia accompanied by pyogenic arthritis, provoking hemorrhagic stroke. Genetic variants are linked to increased risk for stroke in cocaine abuse. The fact that case reports on cannabis-induced stroke usually refer to the young population is very alarming

    Performance of fully instrumented detector planes of the forward calorimeter of a Linear Collider detector

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    Detector-plane prototypes of the very forward calorimetry of a future detector at an e+e- collider have been built and their performance was measured in an electron beam. The detector plane comprises silicon or GaAs pad sensors, dedicated front-end and ADC ASICs, and an FPGA for data concentration. Measurements of the signal-to-noise ratio and the response as a function of the position of the sensor are presented. A deconvolution method is successfully applied, and a comparison of the measured shower shape as a function of the absorber depth with a Monte-Carlo simulation is given.Comment: 25 pages, 32 figures, revised version following comments from referee

    ECFA Detector R&D Panel, Review Report

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    Two special calorimeters are foreseen for the instrumentation of the very forward region of an ILC or CLIC detector; a luminometer (LumiCal) designed to measure the rate of low angle Bhabha scattering events with a precision better than 103^{-3} at the ILC and 102^{-2} at CLIC, and a low polar-angle calorimeter (BeamCal). The latter will be hit by a large amount of beamstrahlung remnants. The intensity and the spatial shape of these depositions will provide a fast luminosity estimate, as well as determination of beam parameters. The sensors of this calorimeter must be radiation-hard. Both devices will improve the e.m. hermeticity of the detector in the search for new particles. Finely segmented and very compact electromagnetic calorimeters will match these requirements. Due to the high occupancy, fast front-end electronics will be needed. Monte Carlo studies were performed to investigate the impact of beam-beam interactions and physics background processes on the luminosity measurement, and of beamstrahlung on the performance of BeamCal, as well as to optimise the design of both calorimeters. Dedicated sensors, front-end and ADC ASICs have been designed for the ILC and prototypes are available. Prototypes of sensor planes fully assembled with readout electronics have been studied in electron beams.Comment: 61 pages, 51 figure
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