460 research outputs found
Nanoferroelectric perovskite oxides with unusual morphology produced by different synthesis procedures
We report in the present paper some original results of a joint research performed in the framework of the COST Action 539 ELENA. In search of higher miniaturisation of electroceramic devices a new outlook seems to arise from ceramics with unusual morphology that might present a new kind of circular or toroidal ferroelectric ordering of dipoles. Completely new perspectives in data storage can be expected if a close control of size confinement and dimensionality as well as of the chemical composition and the phase purity is reached. We succeeded in the fabrication of BaTiO3 hollow nanoparticles and nanowires, and Bi4Ti3O12 platelets. The use of soft chemistry and solid state methods allowed to produce coreshell powders and ferroelectric-ferromagnetic composites with completely new functional properties
Session 8: \u3cem\u3eStatistical Discrimination Methods for Forensic Source Interpretation of Aluminum Powders in Explosives\u3c/em\u3e
Aluminum (Al) powder is often used as a fuel in explosive devices; therefore, individuals attempting to make illegal improvised explosive devices often obtain it from legitimate commercial products or make it themselves using readily available Al starting materials. The characterization and differentiation between sources of Al powder for additional investigative and intelligence value has become increasingly important. Previous research modeled the distributions of micromorphometric features of Al powder particles within a subsample to support Al source discrimination. Since then, additional powder samples from a variety of different source types have been obtained and analyzed, providing a more comprehensive dataset for applying the two statistical methods for interpretation and discrimination of source. Here, we compare two different statistical techniques: one using linear discriminant analysis (LDA), and the other using a modification to the method used in ASTM E2927-16e1 and E2330-19. The LDA method results in an Al source classification for each questioned sample. Alternatively, our modification to the ASTM method uses an interval-based match criterion to associate or exclude each of the known sources as the actual source of a trace. Although the outcomes of these two statistical methods are fundamentally different, their performance with respect to the closed-set identification of source problem is compared. Additionally, the modified ASTM method will be adapted to provide a vector of scores in lieu of the binary decision as the first step towards a score-based likelihood ratio for interpreting Al powder micromorphometric measurement data
Sudden death after valve-in-valve procedure due to delayed coronary obstruction. A case report
Background: Valve-in-valve transcatheter aortic valve implantation for degenerated aortic bioprostheses is an effective option for patients at high risk for redo surgery, even if it may be burdened by complications more common in specific settings, such as, coronary artery obstruction. Case presentation: We present the case of a Caucasic 84-year-old woman with degeneration of a previously implanted aortic Mitroflow bioprosthesis. She underwent a valve-in-valve transcatheter aortic valve implantation with a CoreValve® bioprosthesis. End-procedure coronary angiography demonstrated maintained perfusion of both coronary arteries. However, few hours later, she experienced sudden cardiac death. An autopsy showed that Mitroflow prosthesis leaflets were higher than the left main coronary ostium, and no other possible cause for the sudden death. Fatality was thus ascribed to left main coronary ostium obstruction due to apposition of the Mitroflow leaflet pushed upward by the late expansion of CoreValve®. Conclusions: Coronary artery obstruction is a frequently fatal complication which usually presents just after valve implantation, but, as reported in our case, it may also have a delayed presentation. Accurate patient's selection and intraoperative preventive measures can reduce this eventuality
Anterior mitral valve aneurysm is an uncommon complication of aortic valve infective endocarditis. A case report
Objective: Rare disease Background: Mitral valve aneurysms (MVAs) are uncommon conditions frequently associated with aortic valve endocarditis. They may be complicated by perforation and severe mitral regurgitation (MR). Optimal treatment of MVA, and in particular the best timing for surgery, are uncertain. Case Report: A 62-year-old man with a recent history of dental surgery presented to the Emergency Department complaining relapsing fever. A first echocardiogram demonstrated infective endocarditis of the aortic valve. The patient was primarily managed with specific antibiotic therapy. Despite this, a few days later he suffered from splen-ic embolization and an MVA with MR was detected. Surgical replacement of the mitral and aortic valves was therefore performed. Conclusions: MVAs are infrequent but potentially severe complications of AV endocarditis. In the absence of definite treatment indication, the correct time for surgery should depend on concomitant clinical and infective features
Encuesta preliminar sobre influenza en ganado de carne
La influenza se ha convertido en la enfermedad más ampliamente difundida debido a los brotes producidos en Asia en las aves y su potencial zoonótico. No mucho se ha estudiado en el ganado vacuno (Pearson, 2002; Ducatez et al 2015); aves acuáticas de vida libre son el reservorio natural de los virus de influenza A y conviven con la ganadería de pastizal. La influenza aviar de alta patogenicidad (IAAP), causada por el virus de la influenza aviar subtipo H5N1/2 representa uno de los mayores problemas de salud de los animales. Ningún virus de este subtipo y linaje asiático se ha detectado en Sudamérica (Buscaglia, 2011). La vigilancia es esencial en la detección temprana y el posterior control de esta enfermedad. Debido a que los anticuerpos contra el virus de la influenza pueden persistir después de la propagación del virus a partir del animal infectado, las pruebas serológicas pueden proporcionar un método relativamente simple y barato para detectar la infección (Swayne et al. 2008).Facultad de Ciencias Veterinaria
Spontaneous superconducting islands and Hall voltage in clean superconductors
We study a clean superconductor in the Hall configuration, in the framework
of a purely dissipative time-dependent Ginzburg--Landau theory. We find
situations in which the order parameter differs significantly from zero in a
set of islands that appear to form a periodic structure. When the pattern of
islands becomes irregular, it moves in or against the direction of the current
and a Hall voltage is found. Tiny differences in the initial state may reverse
the sign of the Hall voltage. When the average Hall voltage vanishes, the local
Hall voltage does not necessarily vanish. We examine the influence that several
boundary conditions at the electrodes have on these effects.Comment: 6 pages, Includes additional cases and more detailed result
3D Multispectral Imaging for Cultural Heritage Preservation: The Case Study of a Wooden Sculpture of the Museo Egizio di Torino
Digitalization techniques, such as photogrammetry (PG), are attracting the interest of experts in the cultural heritage field, as they enable the creation of three-dimensional virtual replicas of historical artifacts with 2D digital images. Indeed, PG allows for acquiring data regarding the overall appearance of an artifact, its geometry, and its texture. Furthermore, among several image-based techniques exploited for the conservation of works of art, multispectral imaging (MSI) finds great application in the study of the materials of historical items, taking advantage of the different responses of materials when exposed to specific wavelengths. Despite their great usefulness, PG and MSI are often used as separate tools. Integrating radiometric and geometrical data can notably expand the information carried by a 3D model. Therefore, this paper presents a novel research methodology that enables the acquisition of multispectral 3D models, combining the outcomes of PG and MSI (Visible (VIS), Ultraviolet-induced Visible Luminescence (UVL), Ultraviolet-Reflected (UVR), and Ultraviolet-Reflected False Color (UVR-FC) imaging) in a single coordinate system, using an affordable tunable set-up and open-source software. The approach has been employed for the study of two wooden artifacts from the Museo Egizio di Torino to investigate the materials present on the surface and provide information that could support the design of suitable conservation treatments
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