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

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)

Electrodynamics of Josephson junctions containing strong ferromagnets

Triplet supercurrents in multilayer ferromagnetic Josephson junctions with misaligned magnetization can penetrate thicker ferromagnetic barriers compared to the singlet component. Although the static properties of these junctions have been extensively studied, the dynamic characteristics remain largely unexplored. Here we report a comprehensive electrodynamic characterization of multilayer ferromagnetic Josephson junctions composed of Co and Ho. By measuring the temperature-dependent current-voltage characteristics and the switching current distributions down to 0.3 K, we show that phase dynamics of junctions with triplet supercurrents exhibits long (in terms of proximity) junction behavior and moderately damped dynamics with renormalized capacitance and resistance. This unconventional behavior possibly provides a different way to dynamically detect triplets. Our results show new theoretical models are required to fully understand the phase dynamics of triplet Josephson junctions for applications in superconducting spintronics.DM, RC, FT would like to thank NANOCOHYBRI project (Cost Action CA 16218). NB acknowledges funding from the British Council through UKIERI programme and Loughborough University. MGB acknowledges funding from EPSRC Programme Grant EP/N017242/1

Fine-needle aspiration biopsy and flow cytometry immunophenotyping of lymphoid and myeloproliferative disorders of the spleen.

BACKGROUND: Flow cytometry (FC) is a useful adjunct to fine-needle aspiration biopsy (FNAB) in the evaluation of lymphoproliferative disorders. The application of FC to FNAB of the spleen (sFNAB) is reported. METHODS: Flow cytometry was performed on 18 sFNAB collected over 3 years. The series comprised 10 cases of non- Hodgkin lymphomas (NHL), 2 cases insufficient for diagnosis, 2 cases of reactive hyperplasia (RH), and 4 cases of myeloid metaplasia (MM). FNAB was performed under ultrasound guidance using a 22-gauge needle. One or two passes were sufficient to prepare a conventional smear that was immediately evaluated to select the cases studied and to prepare a cell suspension for FC. The following fluoresceinated antibodies were used: CD3, CD19/kappa/lambda, FMC7/CD23/CD19, Bcl-2, and CD13/HLA-DR. In six cases, cytospins were also prepared for immunocytochemistry and were tested for CD20 (L26), CD45Ro, and kappa and lambda light chain expression. RESULTS: Flow cytometry contributed to the diagnosis of all cases of NHL by assessing light chain restriction. The specific subtype was also diagnosed by CD19/CD5 and CD 19/CD10 coexpression in two cases. Flow cytometry quantified the percentage of myeloid cells in MM cases and contributed to the cytologic diagnosis showing a polyclonal light chain expression in RH cases.Immunocytochemistry was effective and concordant in four cases. Patients tolerated the sFNAB well and no complications were reported. Cytologic and FC diagnoses were confirmed by follow-up and by histologic evaluation in cases in which splenectomy was performed for therapeutic purposes. CONCLUSION: Flow cytometry applied to sFNAB corroborates the cytologic diagnosis in lymphoid and myeloproliferative disorders of the spleen and allows therapeutic decisions avoiding splenectomy

Post-transplant cerebral toxoplasmosis diagnosed by magnetic resonance imaging.

Cerebral toxoplasmosis is a rare late complication in allogeneic bone marrow transplanted patients. Neuroradiological findings may suggest the correct diagnosis. We report a patient in whom cerebral magnetic resonance imaging (MRI) showed a lesion characteristic of toxoplasmosis. Anti- toxoplasma treatment led to clinical and radiological improvement. MRI seems to be a valid tool for detection and follow-up of cerebral toxoplasmosis

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