A cathodoluminescence study of InP/InGaP axially heterostructured NWs for tandem solar cells.

Axially heterostructured nanowires (NWs) constitute a promising platform for advanced electronic and optoelectronic nanodevices. The presence of different materials in these NWs introduces a mismatch resulting in complex strain distributions susceptible of changing the band gap and carrier mobility. The growth of these NWs presents challenges related to the reservoir effect in the catalysts droplet that affect to the junction abruptness, and the occurrence of undesired lateral growth creating core-shell heterostructures that introduce additional strain. We present herein a cathodoluminescence (CL) analysis on axially heterostructured InP/InGaP NWs with tandem solar cell structure. The CL is complemented with micro Raman, micro photoluminescence (PL), and high resolution transmission electron microscopy measurements. The results reveal the zinc blende structure of the NWs, the presence of a thin InGaP shell around the InP bottom cell, along with its associated strain, and the doping distribution.

Thrombectomy with embed aspiration in acute ischaemic stroke.

BACKGROUND: In addition to stent retrievers, direct aspiration has become a reasonable thrombectomy strategy. OBJECTIVES: We carried out the thrombectomy by guiding the aspiration catheter fully over the clot and performing immediate manual aspiration; we call this procedure "embed aspiration". METHODS: In this prospective, non-randomised, single-centre study, we included all patients treated at a high volume-of-care stroke centre between 2017 and 2018 for the TRIANA (Thrombectomy in Andalusia using Aspiration) registry. Thrombectomy was carried out by embed aspiration. Patients were classified according to the success (eTICI 2b67-2c-3) or failure (eTICI 0-1-2a-2b50) of the procedure. Baseline clinical data and outcomes were compared, and multivariate analysis was performed. RESULTS: The embed aspiration technique was used in 370 patients. Treatment was successful in 90.3% of patients. Mean puncture-to-recanalisation time was 25 minutes. The overall rate of good outcomes (mRS 0-2) at 3 months was 64%. CONCLUSIONS: This study supports real-life evidence that standardised embed aspiration may be an alternative to stent retrievers for thrombectomy.

Antithrombotic Treatment after Carotid Stenting in Patients with Concomitant Atrial Fibrillation.

BACKGROUND AND PURPOSE: Antithrombotic therapy following carotid artery stent placement with concomitant atrial fibrillation is not well-established. Our aim was to assess the safety and efficacy of the combination of direct oral anticoagulants and a P2Y12 inhibitor at 30 days after carotid artery stent placement in patients with atrial fibrillation. MATERIALS AND METHODS: We designed an observational single-center study including patients who underwent carotid artery stent placement with concomitant atrial fibrillation. We studied 3 groups according to antithrombotic therapy: 1) the direct oral anticoagulants plus clopidogrel (DC) group: receiving direct oral anticoagulants plus a P2Y12 inhibitor; 2) the triple therapy group: anticoagulation and dual antiplatelet therapy; and 3) the dual antiplatelet therapy group: following dual antiplatelet therapy alone. The safety outcome was a major or clinically relevant non-major bleeding event at the first month. The efficacy outcomes were the thromboembolic events (myocardial infarction, stroke, systemic embolism, or stent thrombosis). RESULTS: Of 959 patients with carotid artery stent placement, 91 met the inclusion criteria, including 24 patients in the DC group, 42 patients in the triple therapy group, and 25 in the dual antiplatelet therapy group. The mean age was 72.27 (SD, 8.1 ) years, with similar baseline characteristics. The median CHA2DS2-VASc score for each group was 6 (interquartile range = 5-6), 5 (interquartile range = 4-6), and 5 (interquartile range = 4-6), respectively. The median HAS-BLED score was 4 in the 3 groups (P = .17). The primary safety end point was 23.8% in the triple therapy group compared with 4% in the dual antiplatelet therapy group (P = .032), with no bleeding events in the DC group (P = .007). There was 1 stent thrombosis in DC group and a cardioembolic stroke in the dual antiplatelet therapy group (P = .41). CONCLUSIONS: Among patients with carotid artery stent placement with atrial fibrillation, triple therapy confers a high bleeding risk. A regimen of direct oral anticoagulants plus a P2Y12 inhibitor might confer a good safety profile with significantly lower rates of bleeding and optimal efficacy.

Tuning the size, composition and structure of Au and Co50Au50 nanoparticles by high-power impulse magnetron sputtering in gas-phase synthesis.

Gas-phase synthesis of nanoparticles with different structural and chemical distribution is reported using a circular magnetron sputtering in an ion cluster source by applying high-power impulses. The influence of the pulse characteristics on the final deposit was evaluated on Au nanoparticles. The results have been compared with the more common direct current approach. In addition, it is shown for the first time that high-power impulses in magnetron based gas aggregation sources allows the growth of binary nanoparticles, CoAu in this case, with a variety of crystalline and chemical arrangements which are analyzed at the atomic level.

Trombólisis intravenosa y trombectomía en paciente joven con ictus isquémico por mixoma auricular desconocido: ¿hay suficiente evidencia en los recientes ensayos clínicos de reperfusión para estos casos? / Intravenous thrombolysis and thrombectomy in young patients with ischaemic stroke due to undetected atrial myxoma: Do recent clinical trials provide sufficient evidence to support reperfusion in these cases?

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Self-organised silicide nanodot patterning by medium-energy ion beam sputtering of Si(100): local correlation between the morphology and metal content.

We have produced self-organised silicide nanodot patterns by medium-energy ion beam sputtering (IBS) of silicon targets with a simultaneous and isotropic molybdenum supply. Atomic force microscopy (AFM) studies show that these patterns are qualitatively similar to those produced thus far at low ion energies. We have determined the relevance of the ion species on the pattern ordering and properties. For the higher ordered patterns produced by Xe(+) ions, the pattern wavelength depends linearly on the ion energy. The dot nanostructures are silicide-rich as assessed by x-ray photoelectron spectroscopy (XPS) and emerge in height due to their lower sputtering yield, as observed by electron microscopy. Remarkably, a long wavelength corrugation is observed on the surface which is correlated with both the Mo content and the dot pattern properties. Thus, as assessed by electron microscopy, the protrusions are Mo-rich with higher and more spaced dots on their surface whereas the valleys are Mo-poor with smaller dots that are closer to each other. These findings indicate that there is a correlation between the local metal content of the surface and the nanodot pattern properties both at the nanodot and the large corrugation scales. These results contribute to advancing the understanding of this interesting nanofabrication method and aid in developing a comprehensive theory of nanodot pattern formation and evolution.

Modified energetics and growth kinetics on H-terminated GaAs (110).

Atomic hydrogen modification of the surface energy of GaAs (110) epilayers, grown at high temperatures from molecular beams of Ga and As4, has been investigated by friction force microscopy (FFM). The reduction of the friction force observed with longer exposures to the H beam has been correlated with the lowering of the surface energy originated by the progressive de-relaxation of the GaAs (110) surface occurring upon H chemisorption. Our results indicate that the H-terminated GaAs (110) epilayers are more stable than the As-stabilized ones, with the minimum surface energy value of 31 meV∕Å(2) measured for the fully hydrogenated surface. A significant reduction of the Ga diffusion length on the H-terminated surface irrespective of H coverage has been calculated from the FFM data, consistent with the layer-by-layer growth mode and the greater As incorporation coefficient determined from real-time reflection high-energy electron diffraction studies. Arsenic incorporation through direct dissociative chemisorption of single As4 molecules mediated by H on the GaAs (110) surface has been proposed as the most likely explanation for the changes in surface kinetics observed.

Nanostructuring of ultra-thin HfO2 layers for high-k/III-V device application.

We report on the nanopatterning by electron beam lithography (EBL) and reactive ion etching (RIE) in a SF6/Ar+ plasma of ultra-thin HfO2 films deposited on GaAs (001) substrates for gate oxide application in next generation III-V metal-oxide-semiconductor field effect transistors (MOSFETs). Characterization of the HfO2/GaAs nanostructured samples by atomic force microscopy (AFM), high-resolution scanning electron microscopy (HRSEM), energy-dispersive X-ray spectroscopy microanalysis (EDX) and transmission electron microscopy (TEM) has shown the formation of well defined HfO2 patterns with nanometre-scale linewidth control and anisotropic profiles. In addition, atomically smooth, stoichiometric and residue-free bottom GaAs etched lines with a lateral dimension of approximately 50 nm have been demonstrated.