Scanning tunneling microscopy has been used to real-time study the growth of silicene on Ag(111) in the 200-533-K temperature range. We show that the growth mode depends strongly on the deposition ...temperature T. At T = 300 K and above, the formation of silicene results from the exchange between surface Ag atoms and Si atoms, which are inserted in the substrate top layer. Density functional theory calculations confirm that Si insertion is thermodynamically favored, and we propose an energetic model for explaining the observed growth processes as a function of T. For T > or = 400 K, ordered structures are observed as soon as silicene domains are large enough. With increasing coverage, disordered and dotted phases progressively transform into stable (radical13 x radical13) R13.9degrees and (4 x 4) structures.
We present a state-of-the-art study of the optical properties of free-standing silicene and of single-layer Si one- and two-dimensional (1D and 2D) nanostructures supported on Ag(110) and Ag(111) ...substrates. Ab initio simulations of reflectance anisotropy spectroscopy (RAS) and surface differential reflectivity spectroscopy (SDRS) applied to the clean Ag surface and Si/Ag interfaces are compared with new measurements. For Si/Ag(110), we confirm a pentagonal nanoribbon geometry, strongly bonded to the substrate, and rule out competing zigzag chain and silicenelike models. For Si/Ag(111), we reproduce the main experimental features and isolate the optical signal of the epitaxial silicene overlayer. The absorption spectrum of a silicene sheet computed including excitonic and local field effects is found to be quite similar to that calculated within an independent particle approximation and shows strong modifications when adsorbed on a Ag substrate. Important details of the computational approach are examined and the origins of the RAS and SDRS signals are explained in terms of the interface and substrate response functions. Our study does not find any evidence for Si adlayers that retain the properties of freestanding silicene.
New World cutaneous leishmaniasis (CL) is endemic in many countries of Latin America, including French Guiana 1. While pentamidine is the first‐line treatment against Leishmania guyanensis in this ...territory 2, pentavalent antimonials such as meglumine antimoniate (MA) are recommended in case of L. braziliensis or pentamidine‐resistant strains of other species 2. Liposomal amphotericin B (L‐AmB) (Ambisome ®) is widely used against fungi and visceral leishmaniasis 3. However, data concerning its efficacy in New World CL are scarce and contradictory 4‐7. Due to a shortage in MA, the Cayenne Hospital started using L‐AmB as an alternative in 2015. We conducted a retrospective study to compare efficacy and safety of L‐AmB and MA in patients treated for CL.
SPACIROC3: 100 MHz photon counting ASIC for EUSO-SPB Blin, S.; Barrillon, P.; de La Taille, C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2018, Letnik:
912
Journal Article
Recenzirano
SPACIROC (Spatial Photomultiplier Array Counting and Integrating ReadOut Chip) is the front-end ASIC dedicated to readout 64-channel Multi-Anode Photo-Multiplier Tube (MAPMT). In 2017, it was used ...for the Extreme Universe Space Observatory on a super pressure balloon (EUSO-SPB) instrument which is a pathfinder for space cosmic ray fluorescence detectors. EUSO-SPB was launched by NASA from Wanaka, NZ on the 24th of April 2017. The flight has been a success both on technological and scientific point of views. The instrument was equipped with a set of lenses to focus the UV photons on the Photo Detector Module (PDM) which was controlled by the Data Processing system. The photo detection focal surface is made of 36 MAPMTs with high voltage sub-system (HVPS). The MAPMT signals are transmitted to SPACIROC3 ASIC which performs single photon counting with low power consumption (<1 mW/ch). This proceeding presents in detail the performances of the SPACIROC3 ASIC.
Complications following COVID-19 are starting to emerge; neurological disorders are already described in the literature.
This case is about a 20-year old male with a severe COVID-19, hospitalized in ...a Reanimation and Intensive Care Unit with an Acute Respiratory Distress Syndrome, thromboembolic complication and secondary bacterial infection. This patient had a non-specific neurological disorder with a pseudobulbar palsy, (MRI, ENMG and lumbar puncture were normal), associated 4 months later with persistent left shoulder motor deficit and respiratory failure. Respiratory and neurological check-up led to a diagnosis of the Parsonage-Turner syndrome or neuralgic amyotrophy affecting C5-C6 nerve roots, the lateral pectoral and phrenic nerves at the origin of the scapular belt, amyotrophy and left diaphragm paralysis.
This case shows that persistant dyspnoea after COVID 19 infection should lead to a search for a diaphragmatic cause which is not always the result of Reanimation Neuropathy but may also indicate a neuralgic amyotrophy. It is the fourth case of neuralgic amyotrophy following COVID-19. This brings the medical community to consider the risk of diaphragm paralysis apart from critical illness polyneuropathy. Respiratory muscle evaluation and diaphragmatic ultrasound should be considered in case of persistent dyspnoea.
Unveiling the self-organization mechanism of semiconducting organic molecules onto metallic surfaces is the first step to design hybrid devices in which the self-assembling is exploited to tailor ...magnetic properties. In this study, double-decker rare-earth phthalocyanines, namely, lutetium phthalocyanine (LuPc2), are deposited on Au(111) gold surface forming large-scale self-assemblies. Global and local experimental techniques, namely, grazing incidence X-ray diffraction and scanning tunneling microscopy, supplemented by density functional theory calculations with van der Waals corrections, give insight into the molecular structural arrangement of the thin film and the self-organization at the surface. Our results show unambiguously that the two plateaus of the double-decker phthalocyanine present a different rotation than the isolated molecule. This is evidenced by density functional theory simulations of optimized LuPc2 monolayer showing a perfect agreement with experimental findings. Moreover, the stabilized structure of double layers reveals an eclipsed configuration of the molecules in the stacking, having the ligand plateaus parallel to the gold surface. The high crystallinity of the molecular assembly and its weak electronic coupling with the metallic substrate is expected to open new perspective in the design of optoelectronic or magnetic devices.
The oxidation of CO to CO2 has been investigated on Pt(997) single-crystal model catalysts with a flow reactor near ambient pressure with X-ray diffraction. Depending on the temperature and gas ...composition, the surface may consist of monatomic steps separated by 9 atom wide terraces or diatomic steps separated by 18 atom wide terraces. The diatomic stepped surface has been found to be significantly more active for CO2 production. The kinetics of the single- to double-step transition under reaction conditions has been investigated, as well as the dependence of the transition temperature with the gas composition.
This study aims to describe the haemodynamic and survival characteristics of patients with pulmonary hypertension in the recently individualised syndrome of combined pulmonary fibrosis and emphysema. ...A retrospective multicentre study was conducted in 40 patients (38 males; age 68+/-9 yrs; 39 smokers) with combined pulmonary fibrosis and emphysema, and pulmonary hypertension at right heart catheterisation. Dyspnoea was functional class II in 15%, III in 55% and IV in 30%. 6-min walk distance was 244+/-126 m. Forced vital capacity was 86+/-18%, forced expiratory volume in 1 s 78+/-19%, and carbon monoxide diffusion transfer coefficient 28+/-16% of predicted. Room air arterial oxygen tension was 7.5+/-1.6 kPa (56+/-12 mmHg). Mean pulmonary artery pressure was 40+/-9 mmHg, cardiac index 2.5+/-0.7 L x min(-1) x m(-2) and pulmonary vascular resistance 521+/-205 dyn x s x cm(-5). 1-yr survival was 60%. Higher pulmonary vascular resistance, higher heart rate, lower cardiac index and lower carbon monoxide diffusion transfer were associated with shorter survival. Patients with combined pulmonary fibrosis and emphysema syndrome and pulmonary hypertension confirmed by right heart catheterisation have a dismal prognosis despite moderately altered lung volumes and flows and moderately severe haemodynamic parameters.
The second generation Extreme Universe Space Observatory on a Super-Pressure Balloon (EUSO-SPB2) mission is on track to be approved by NASA for a long duration flight (up to 100 days) in 2023 from ...Wanaka, New Zealand. EUSO-SPB2 will monitor the night atmosphere of the Southern hemisphere from 33 km altitude to detect Ultra-High Energy Cosmic Rays (UHECRs) and search for astrophysical and cosmogenic neutrinos. EUSO-SPB2 features two telescopes, a Cherenkov (CT) and a Fluorescence (FT) Telescope. The hardware implementation and performance of the FT trigger logic were tested at the TurLab facility, hosted at the University of Turin. The tests proved the correct hardware implementation of the trigger logic and its ability to detect μs timescale transient signals.
Immune checkpoint inhibitors are becoming a standard treatment for many different cancers. Their toxicities are variable and include organ-specific dysimmune injuries and the development of systemic ...diseases.
We report 3 cases of sarcoid-like granulomatosis that occurred during treatment of various types of primary cancer by immune checkpoint inhibitors: lung adenocarcinoma, small cell lung cancer and melanoma. The clinical presentation, radiologic pattern and severity of this toxicity were variable. The diagnosis was made on biopsy with pathological examination and exclusion of differential diagnoses, particularly infection. In such cases, immunotherapy should be discontinued and subsequent rechallenge discussed later. Systemic corticosteroids should be considered depending on the severity of symptoms.
Knowledge of this toxicity is crucial as the clinical signs and radiological patterns may suggest tumour progression.
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