Al-Substitution Effects on Physical Properties of the Colossal Magnetoresistance Compouns La0.67ca0.33mno3

We present a detailed study of the polycrystalline perovskite manganites La0.67Ca0.33AlxMn1-xO3 (x = 0, 0.1, 0.15, 0.5) at low temperatures and high magnetic fields, including electrical resistance, magnetization, ac susceptibility. The static magnetic susceptibility was also measured up to 1000 K. All the samples show colossal magnetoresistance behavior and the Curie temperatures decrease with Al doping. The data suggest the presence of correlated magnetic clusters near by the ferromagnetic transition. This appears to be a consequence of the structural and magnetic disorder created by the random distribution of Al atoms.Comment: 13 pages including 5 figure

Non-quasiparticle states in Co2_2MnSi evidenced through magnetic tunnel junction spectroscopy measurements

We investigate the effects of electronic correlations in the full-Heusler Co$_2$MnSi, by combining a theoretical analysis of the spin-resolved density of states with tunneling-conductance spectroscopy measurements using Co$_2$MnSi as electrode. Both experimental and theoretical results confirm the existence of so-called non-quasiparticle states and their crucial contribution to the finite-temperature spin polarisation in this material.Comment: Repalced Fig. 1. of PRL, 100, 086402 (2008), better k-space resolution for DOS around Fermi energ

A Coupled Thermoreflectance Thermography Experimental System and Ultra-Fast Adaptive Computational Engine for the Complete Thermal Characterization of Three-Dimensional Electronic Devices : Validation

This work builds on the previous introduction [1] of a coupled experimental-computational system devised to fully characterize the thermal behavior of complex 3D submicron electronic devices. The new system replaces the laser-based surface temperature scanning approach with a CCD camera-based approach. As before, the thermo-reflectance thermography system is used to non-invasively measure with submicron resolution the 2D surface temperature field of an activated device. The measured temperature field is then used as input for an ultra-fast inverse computational solution to fully characterize the thermal behavior of the complex three-dimensional device. For the purposes of this investigation, basic micro-heater devices were built, activated, and measured. In order to quantitatively validate the coupled experimental-computational system, the system was used to extract geometric features of a known device, thus assessing the system's ability to combine measured experimental results and computations to fully characterize complex 3D electronic devices

CCD thermoreflectance thermography system : methodology and experimental validation

This work introduces a thermoreflectance-based system designed to measure the surface temperature field of activated microelectronic devices at submicron spatial resolution with either a laser or a CCD camera. The article describes the system, outlines the measurement methodology, and presents validation results. The thermo-reflectance thermography (TRTG) system is capable of acquiring device surface temperature fields at up to 512\u81 512 points with 0.2 ƒÊm resolution. The setup and measurement methodology are presented, along with details of the calibration process required to convert changes in measured surface reflectivity to absolute temperatures. To demonstrate the system\u81fs capabilities, standard gold micro-resistors are activated and their surface temperature fields are measured. The results of the CCD camera and our existing laser-based measurement approaches are compared and found to be in very good agreement. Finally, the system is validated by comparing the temperatures obtained with the TRTG method with those obtained from electrical resistance measurements

Does chronic oral anticoagulation reduce in-hospital mortality among COVID-19 older patients?

Background: Patients hospitalized with COVID-19 experienced an increased risk of venous thromboembolism. Aims: To evaluate the effect of chronic oral anticoagulation (OAC) therapy, both with vitamin K antagonists (VKAs) or direct oral anticoagulants (DOACs), on prognosis of COVID-19 older patients. Methods: Single-center prospective study conducted in the Emergency Department (ED) of a teaching hospital, referral center for COVID-19 in central Italy. We evaluated all the patients ≥ 65 years, consecutively admitted to our ED for confirmed COVID-19. We compared the clinical outcome of those who were on chronic OAC at ED admission with those who did not, using a propensity score matched paired cohort of controls. The primary study endpoint was all-cause in-hospital death. Patients were matched for age, sex, clinical comorbidities, and clinical severity at presentation (based on NEWS ≥ 6). Study parameters were assessed for association to all-cause in-hospital death by a multivariate Cox regression analysis to identify independent risk factor for survival. Results: Although overall mortality was slightly higher for anticoagulated patients compared to controls (63.3% vs 43.5%, p = 0.012), the multivariate adjusted hazard ratio (HR) for death was not significant (HR = 1.56 [0.78–3.12]; p = 0.208). Both DOACs (HR 1.46 [0.73–2.92]; p = 0.283) and VKAs (HR 1.14 [0.48–2.73]; p = 0.761) alone did not affect overall survival in our cohort. Conclusions: Among older patients hospitalized for COVID-19, chronic OAC therapy was not associated with a reduced risk of in-hospital death. Moreover, our data suggest similar outcome both for patients on VKAs or in patients on DOACs