Search

Avalanche resistive switching is the fundamental process that triggers the sudden change of the electrical properties in solid-state devices under the action of intense electric fields. Despite its relevance for information processing, ultrafast electronics, neuromorphic devices, resistive memories and brain-inspired computation, the nature of the local stochastic fluctuations that drive the formation of metallic regions within the insulating state has remained hidden. Here, using operando X-ray nano-imaging, we have captured the origin of resistive switching in a V 2 O 3 -based device under working conditions. V 2 O 3 is a paradigmatic Mott material, which undergoes a first-order metal-to-insulator phase transition together with a lattice transformation that breaks the threefold rotational symmetry of the rhombohedral metallic phase. We reveal a new class of volatile electronic switching triggered by nanoscale topological defects appearing in the shear-strain based order parameter that describes the insulating phase. Our results pave the way to the use of strain engineering approaches to manipulate such topological defects and achieve the full dynamical control of the electronic Mott switching. Topology-driven, reversible electronic transitions are relevant across a broad range of quantum materials, comprising transition metal oxides, chalcogenides and kagome metals., (© 2024. The Author(s).)

Background: Cardiac magnetic resonance (CMR) plays a pivotal diagnostic role in myocardial infarction with nonobstructive coronary arteries (MINOCA). To date, a prognostic stratification of these patients is still lacking., Objectives: This study aims to assess the prognostic role of CMR in MINOCA., Methods: The authors assessed 437 MINOCA from January 2017 to October 2021. They excluded acute myocarditis, takotsubo syndromes, cardiomyopathies, and other nonischemic etiologies. Patients were classified into 3 subgroups according to the CMR phenotype: 1) presence of late gadolinium enhancement (LGE) and abnormal mapping (M) values (LGE+/M+); 2) regional ischemic injury with abnormal mapping and no LGE (LGE-/M+); and 3) nonpathological CMRs (LGE-/M-). The primary outcome was the presence of major adverse cardiovascular events (MACE). The mean follow-up was 33.7 ± 12.0 months and CMR was performed on average at 4.8 ± 1.5 days from the acute presentation., Results: The final cohort included 198 MINOCA; 116 (58.6%) comprised the LGE+/M+ group. During follow-up, MACE occurred significantly more frequently in MINOCA LGE+/M+ than in the LGE+/M- and normal-CMR (LGE-/M-) subgroups (20.7% vs 6.7% and 2.7%; P = 0.006). The extension of myocardial damage at CMR was significantly greater in patients who developed MACE. In multivariable Cox regression, %LGE was an independent predictor of MACE (HR: 1.123 [95% CI: 1.064-1.185]; P < 0.001) together with T2 mapping values (HR: 1.190 [95% CI: 1.145-1.237]; P = 0.001)., Conclusions: In MINOCA with early CMR execution, the %LGE and abnormal T2 mapping values were identified as independent predictors of adverse cardiac events at ∼3.0 years of follow-up. These parameters can be considered as high-risk markers in MINOCA., Competing Interests: Funding Support and Author Disclosures Dr Bucciarelli-Ducci has received speaker fees from Circle Cardiovascular Imaging, Bayer, Siemens Healthineers; and is the Chief Executive Officer (part-time) for the Society for Cardiovascular Magnetic Resonance. Dr Paolisso is supported by a research grant from the CardioPaTh PhD Program. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

The term cardiac mass refers to benign or malignant cardiac tumors and cardiac metastases but also to pseudotumors, which is a heterogeneous group consisting of thrombi, vegetations and normal variant structures. While primitive cardiac tumors are rare, metastases and pseudotumors are relatively common. The non-invasive diagnostic approach has not been well established in the literature yet. The first-line non-invasive approach consists of echocardiography, which provides good diagnostic accuracy for masses like thrombi, vegetations and some tumors (mainly myxoma and fibroelastoma). In contrast, for other masses, it does not provide information about the potential malignancy because of poor tissue characterization. Second-line (cardiac computed tomography and cardiac magnetic resonance) or third-line (positron emission tomography-computed tomography) evaluations have been validated in the diagnostic approach to cardiac masses by many studies. In fact, a comprehensive diagnostic approach may establish the diagnosis of malignancy without histological report, which is pivotal for the subsequent therapeutic strategy.The aim of this narrative review is to describe the commonly available non-invasive diagnostic techniques for cardiac masses, their potential and limitations and to suggest a diagnostic pathway for common practice.

Phase transitions are key in determining and controlling the quantum properties of correlated materials. Here, by using the combination of material synthesis and photoelectron spectroscopy, we demonstrate a genuine Mott transition undressed of any symmetry breaking side effects in the thin films of V 2 O 3 . In particular and in contrast with the bulk V 2 O 3 , we unveil the purely electronic dynamics approaching the metal-insulator transition, disentangled from the structural transformation that is prevented by the residual substrate-induced strain. On approaching the transition, the spectral signal evolves slowly over a wide temperature range, the Fermi wave-vector does not change, and the critical temperature is lower than the one reported for the bulk. Our findings are fundamental in demonstrating the universal benchmarks of a genuine nonsymmetry breaking Mott transition, extendable to a large array of correlated quantum systems, and hold promise of exploiting the metal-insulator transition by implementing V 2 O 3 thin films in devices.

Mott transitions in real materials are first order and almost always associated with lattice distortions, both features promoting the emergence of nanotextured phases. This nanoscale self-organization creates spatially inhomogeneous regions, which can host and protect transient non-thermal electronic and lattice states triggered by light excitation. Here, we combine time-resolved X-ray microscopy with a Landau-Ginzburg functional approach for calculating the strain and electronic real-space configurations. We investigate V 2 O 3 , the archetypal Mott insulator in which nanoscale self-organization already exists in the low-temperature monoclinic phase and strongly affects the transition towards the high-temperature corundum metallic phase. Our joint experimental-theoretical approach uncovers a remarkable out-of-equilibrium phenomenon: the photo-induced stabilisation of the long sought monoclinic metal phase, which is absent at equilibrium and in homogeneous materials, but emerges as a metastable state solely when light excitation is combined with the underlying nanotexture of the monoclinic lattice., (© 2022. The Author(s).)

In periodic systems of interacting electrons, Fermi and Luttinger surfaces refer to the locations within the Brillouin zone of poles and zeros, respectively, of the single-particle Green's function at zero energy and temperature. Such difference in analytic properties underlies the emergence of well-defined quasiparticles close to a Fermi surface, in contrast to their supposed non-existence close to a Luttinger surface, where the single-particle density-of-states vanishes at zero energy. We here show that, contrary to such common belief, dispersive 'quasiparticles' with infinite lifetime do exist also close to a pseudo-gapped Luttinger surface. Thermodynamic and dynamic properties of such 'quasiparticles' are just those of conventional ones. For instance, they yield well-defined quantum oscillations in Luttinger surface and linear-in-temperature specific heat, which is striking given the vanishing density of states of physical electrons, but actually not uncommon in strongly correlated materials., (© 2022. The Author(s).)

We compare two different notions of dynamical phase transitions in closed quantum systems. The first is identified through the time-averaged value of the equilibrium-order parameter, whereas the second corresponds to non-analyticities in the time behaviour of the Loschmidt echo. By exactly solving the dynamics of the infinite-range XY model, we show that in this model non-analyticities of the Loschmidt echo are not connected to standard dynamical phase transitions and are not robust against quantum fluctuations. Furthermore, we show that the existence of either of the two dynamical transitions is not necessarily connected to the equilibrium quantum phase transition., (© 2016 The Author(s).)

The Authors report their experience with the surgical treatment of incisional hernias over the period from July 2000 to June 2004 in the Division of General Surgery of the Department of Surgical Sciences of the University of Foggia where 22 patients were operated on. Nine of them had an incisional hernia of considerable size, while in the other 13 patients the hernia was less voluminous. The authors emphasise the essential role of synthetic prostheses (polypropylene) which now replace and supersede the reabsorbable ones which have fallen into disuse due to the lack of guarantees regarding their strength over lengthy periods. An interdisciplinary approach is now mandatory for a pathology which requires the contribution of many different healthcare operatives such as cardiologists, respiratory physiopathologists, physiokinesitherapists, endocrinologists and resuscitators who all share in the work of the surgeon who represents the last link in the chain and has the technical task of resolving the basic pathology. The technique adopted for the larger incisional hernias was a Ramirez abdominoplasty, the first step of which consists in a very meticulous separation of the different structures of the abdominal wall followed by synthesis of the different anatomical layers with the application of polypropylene meshes. Our results in terms of intra- and postoperative mortality, complicating diseases and hospitalisation are compared with those reported in other studies using the Rives technique.

The Authors report a case of Zenker's diverticulum seen and treated at the University Department of Surgical Sciences of the University of Foggia. The treatment of this condition is invariably surgical and consists in a diverticulectomy combined with a lengthwise extramucosal myotomy. This latter technical adjunct, however, would not appear to be accepted by all Authors. Other techniques have been proposed for the treatment of this condition, but no confirmation of their efficacy exists in the literature. Mortality fluctuates in the various case series, from 0.45% to 8.1%, and the morbidity varies from 5.3% to 40%. The risk of postoperative complications is always present, but can be reduced if the patient undergoes a thorough preoperative investigation.

The Authors report their personal experience with 9 patients affected by cardial cancer and 4 with medio-distal oesophageal cancer, treated at the Department of Surgical Sciences of the University of Foggia. Of the 9 patients with cardial cancers, 4 were submitted to total gastrectomy; while the other 5, who had clearly inoperable forms, were fitted with a self-expanding metal prosthesis (Ultraflex). Of the 4 cases with medio-distal oesophageal cancers, which were considered beyond any kind of surgical treatment, 2 (with stenosing forms) were fitted with the self-expanding prosthesis (Ultraflex), while the other 2 (with friable, bleeding tissue) were treated by laser therapy with all the drawbacks such treatment entails. After application of stents, dysphagia decreases and on the whole we obtain real functional success and a better quality of life. Furthermore, the percentage of acute complications such as profuse bleeding, perforation of the pharynx or migration of the prosthesis and late complications such as obstruction by food, neoplastic obstruction, or haemorrhage is marginal. Finally, the ease of application and the economic saving achieved (due to reduction in hospitalisation time and charges) confer undeniable additional advantages on the procedure.

Near a Mott transition, strong electron correlations may enhance Cooper pairing. This is demonstrated in the dynamical mean field theory solution of a twofold-orbital degenerate Hubbard model with an inverted on-site Hund rule exchange, favoring local spin-singlet configurations. Close to the Mott insulator (which here is a local version of a valence bond insulator) a pseudogap non-Fermi-liquid metal, a superconductor, and a normal metal appear, in striking similarity with the physics of cuprates. The strongly correlated s-wave superconducting state has a larger Drude weight than the corresponding normal state. The role of the impurity Kondo problem is underscored., (Copyright 2004 The American Physical Society)

We study the quasiparticle transport coefficients in disordered d-wave superconductors. We find that spin and charge excitations are generally localized unless magnetic impurities are present. If the system is close to a nesting point in the impurity-scattering unitary limit, the tendency towards localization is reduced while the quasiparticle density of states gets enhanced by disorder. We also show that the residual repulsive interaction among quasiparticles has a delocalizing effect and increases the density of states.