Macroscopic Quantum Tunneling and the "cosmic" Josephson effect

We discuss the possible influence of a cosmic magnetic field on the macroscopic quantum tunneling process associated, in a cosmological context, to the decay of the "false vacuum." We find a close analogy with the effects of an external magnetic field applied to a Josephson junction in the context of low-temperature/high-temperature superconducting devices.Comment: 4 pages, 1 pdf figure. Added references and an inset in Fig. 1, results unchanged. To appear in Phys. Rev. D (Brief Report

Coherent response of a low T_c Josephson junction to an ultrafast laser pulse

By irradiating with a single ultrafast laser pulse a superconducting electrode of a Josephson junction it is possible to drive the quasiparticles (qp's) distribution strongly out of equilibrium. The behavior of the Josephson device can, thus, be modified on a fast time scale, shorter than the qp's relaxation time. This could be very useful, in that it allows fast control of Josephson charge qubits and, in general, of all Josephson devices. If the energy released to the top layer contact $S1$ of the junction is of the order of $\sim \mu J$, the coherence is not degradated, because the perturbation is very fast. Within the framework of the quasiclassical Keldysh Green's function theory, we find that the order parameter of $S1$ decreases. We study the perturbed dynamics of the junction, when the current bias is close to the critical current, by integrating numerically its classical equation of motion. The optical ultrafast pulse can produce switchings of the junction from the Josephson state to the voltage state. The switches can be controlled by tuning the laser light intensity and the pulse duration of the Josephson junction.Comment: 17 pages, 5 figure

Mutual Inductance Route to Paramagnetic Meissner Effect in 2D Josephson Junction Arrays

We simulate two-dimensional Josephson junction arrays, including full mutual- inductance effects, as they are cooled below the transition temperature in a magnetic field. We show numerical simulations of the array magnetization as a function of position, as detected by a scanning SQUID which is placed at a fixed height above the array. The calculated magnetization images show striking agreement with the experimental images obtained by A. Nielsen et al. The average array magnetization is found to be paramagnetic for many values of the applied field, confirming that paramagnetism can arise from magnetic screening in multiply-connected superconductors without the presence of d-wave superconductivity.Comment: REVTeX 3.1, 5 pages, 5 figure

Ultrasound scan to detect acalculous cholecystopathy in immunocompromised hosts with unexplained fever.

We found a significant prevalence of acalculous cholecystopathy in a group of patients with hematologic malignancies and unexplained fever. Ultrasound scan (US) detected a case of acute cholecystitis, two of gallbladder overdistension and biliary sludge, and one of striated gallbladder wall thickening. US proved effective in early identification of abdominal infection site

Intravenous itraconazole for treating invasive pulmonary aspergillosis in neutropenic patients with acute lymphoblastic leukemia.

Aspergillus infection is associated with a high mortality rate in immunocompromised hosts; more effective drugs for this infection are needed. Oral itraconazole has been studied in neutropenic fungus-infected patients. Using a novel formulation (intravenous) of itraconazole, we successfully treated severe necrotizing pneumonias due to Aspergillus species occurring during a postchemotherapy prolonged aplastic phase in two patients with acute lymphoblastic leukemia

Observation of a New Fluxon Resonant Mechanism in Annular Josephson Tunnel Structures

A novel dynamical state has been observed in the dynamics of a perdurbed sine-Gordon system. This resonant state, has been experimentally observed as a singularity in the dc current voltage characteristic of an annular Josephson tunnel junction, excited in the presence of a magnetic field. With this respect, it can be assimilated to self-resonances known as Fiske steps. Differently from these, however, we demonstrate, on the basis of numerical simulations, that its detailed dynamics involves rotating fluxon pairs, a mechanism associated, so far, to self-resonances known as zero-field steps.Comment: 4 pages, 2 figures, submitted to Physical Review Letter

Endothelial cell activation by SARS-CoV-2 spike S1 protein: A crosstalk between endothelium and innate immune cells

Background. Emerging evidences suggest that in severe COVID-19, multi-organ failure is associated with a hyperinflammatory state (the so-called “cytokine storm”) in combination with the development of a prothrombotic state. The central role of endothelial dysfunction in the pathogenesis of the disease is to date accepted, but the precise mechanisms underlying the associated coagulopathy remain unclear. Whether the alterations in vascular homeostasis directly depend upon the SARS-CoV-2 infection of endothelial cells or, rather, occur secondarily to the activation of the inflammatory response is still a matter of debate. Here, we address the effect of the SARS-CoV-2 spike S1 protein on the activation of human lung microvascular endothelial cells (HLMVEC). In particular, the existence of an endothelium-macrophage crosstalk in the response to the spike protein has been explored. Methods and Results. The effect of the spike protein is addressed in human lung microvascular endothelial cells (HLMVEC), either directly or after incubation with a conditioned medium (CM) of human monocyte-derived macrophages (MDM) previously activated by the spike S1 protein (CM-MDM). Both MDM and HLMVEC are activated in response to the S1 protein, with an increased expression of pro-inflammatory mediators. However, when HLMVEC are exposed to CM-MDM, an enhanced cell activation occurs in terms of the expression of adhesion molecules, pro-coagulant markers, and chemokines. Under this experimental condition, ICAM-1 and VCAM-1, the chemokines CXCL8/IL-8, CCL2/MCP1, and CXCL10/IP-10 as well as the protein tissue factor (TF) are markedly induced. Instead, a decrease of thrombomodulin (THBD) is observed. Conclusion. Our data suggest that pro-inflammatory mediators released by spike-activated macrophages amplify the activation of endothelial cells, likely contributing to the impairment of vascular integrity and to the development of a pro-coagulative endothelium

Macroscopic quantum tunnelling in spin filter ferromagnetic Josephson junctions.

The interfacial coupling of two materials with different ordered phases, such as a superconductor (S) and a ferromagnet (F), is driving new fundamental physics and innovative applications. For example, the creation of spin-filter Josephson junctions and the demonstration of triplet supercurrents have suggested the potential of a dissipationless version of spintronics based on unconventional superconductivity. Here we demonstrate evidence for active quantum applications of S-F-S junctions, through the observation of macroscopic quantum tunnelling in Josephson junctions with GdN ferromagnetic insulator barriers. We show a clear transition from thermal to quantum regime at a crossover temperature of about 100 mK at zero magnetic field in junctions, which present clear signatures of unconventional superconductivity. Following previous demonstration of passive S-F-S phase shifters in a phase qubit, our result paves the way to the active use of spin filter Josephson systems in quantum hybrid circuits.We acknowledge financial support from COST Action MP1201 [NanoSC COST], by Progetto FIRB HybridNanoDev RBFR1236VV001 and by Regione Campania through POR Campania FSE 2007/2013, progetto MASTRI CUP B25B09000010007.This is the final version. It was first published by NPG at http://www.nature.com/ncomms/2015/150609/ncomms8376/full/ncomms8376.html#abstract

Liver nodular regenerative hyperplasia after bone marrow transplant.

We report an unusual liver disease which may occur after bone marrow transplantation, i.e. the collapse of hepatic lobuli followed by regenerative islets: the resulting clinical picture may mimic GvHD or a viral disease, but histology is diagnostic, showing nodular regeneration in the absence of inflammation or fibrosis

Detection of non-Hodgkin's lymphoma liver disease in cirrhotic patients

Computer tomography (CT) scan and ultrasound scan (US) are the preferred methods for staging subdiaphragmatic non-Hodgkin’s lymphoma (NHL),1 but their sensitivity in detecting focal lesions in the liver may be reduced if fibrosis is present. We investigated 6 NHL patients who also had a viral liver disease (chronic active hepatitis or cirrhosis) by US and CT liver scans and liver biopsy. US was performed using a Spazio-Hitachi instrument with a 3.5 MHz probe. With the exception of two patients, who underwent laparotomy as a diagnostic procedure, liver biopsy was performed under US guidance using a Menghini fine needle with automatic aspiration (1.2 mm in diameter x 150 mm in length), or a Chiba fine needle (0.7 mm x 150 mm)