49 research outputs found
High-Quality Planar high-Tc Josephson Junctions
Reproducible high-Tc Josephson junctions have been made in a rather simple
two-step process using ion irradiation. A microbridge (1 to 5 ?m wide) is
firstly designed by ion irradiating a c-axis-oriented YBa2Cu3O7-? film through
a gold mask such as the non-protected part becomes insulating. A lower Tc part
is then defined within the bridge by irradiating with a much lower fluence
through a narrow slit (20 nm) opened in a standard electronic photoresist.
These planar junctions, whose settings can be finely tuned, exhibit
reproducible and nearly ideal Josephson characteristics. This process can be
used to produce complex Josephson circuits.Comment: 4 pages, 5 figures, to be published in Applied Physics Letter
Acute Cardiovascular Manifestations in 286 Children With Multisystem Inflammatory Syndrome Associated With COVID-19 Infection in Europe
Background: The aim of the study was to document cardiovascular clinical findings, cardiac imaging, and laboratory markers in children presenting with the novel multisystem inflammatory syndrome associated with coronavirus disease 2019 (COVID-19) infection.
Methods: This real-time internet-based survey has been endorsed by the Association for European Paediatric and Congenital Cardiologists Working Groups for Cardiac Imaging and Cardiovascular Intensive Care. Children 0 to 18 years of age admitted to a hospital between February 1 and June 6, 2020, with a diagnosis of an inflammatory syndrome and acute cardiovascular complications were included.
Results: A total of 286 children from 55 centers in 17 European countries were included. The median age was 8.4 years (interquartile range, 3.8-12.4 years) and 67% were boys. The most common cardiovascular complications were shock, cardiac arrhythmias, pericardial effusion, and coronary artery dilatation. Reduced left ventricular ejection fraction was present in over half of the patients, and a vast majority of children had raised cardiac troponin when checked. The biochemical markers of inflammation were raised in most patients on admission: elevated C-reactive protein, serum ferritin, procalcitonin, N-terminal pro B-type natriuretic peptide, interleukin-6 level, and D-dimers. There was a statistically significant correlation between degree of elevation in cardiac and biochemical parameters and the need for intensive care support (P<0.05). Polymerase chain reaction for severe acute respiratory syndrome coronavirus 2 was positive in 33.6%, whereas immunoglobulin M and immunoglobulin G antibodies were positive in 15.7% cases and immunoglobulin G in 43.6% cases, respectively, when checked. One child in the study cohort died.
Conclusions: Cardiac involvement is common in children with multisystem inflammatory syndrome associated with the Covid-19 pandemic. The majority of children have significantly raised levels of N-terminal pro B-type natriuretic peptide, ferritin, D-dimers, and cardiac troponin in addition to high C-reactive protein and procalcitonin levels. In comparison with adults with COVID-19, mortality in children with multisystem inflammatory syndrome associated with COVID-19 is uncommon despite multisystem involvement, very elevated inflammatory markers, and the need for intensive care support.info:eu-repo/semantics/publishedVersio
Standardizing the experimental conditions for using urine in NMR-based metabolomic studies with a particular focus on diagnostic studies: a review
Etude D'un Supraconducteur A Haute Temperature Critique Par Effet Josephson Et Spectroscopie Tunnel
Andreev bound states and Josephson coupling in YBaCuO/Pb tunnel junctions
5 pages with 2 eps figures, uses jltp.sty, to be published in Journal of Low Temperature Physics (Proceedings of the MOS'99 Conference)We have made in-situ [103] and [110]YBCO/Pb junctions, which display an hysteretic behaviour with both a well-defined Quasi-Particule branch and a Josephson current. A zero energy conductance peak is observed in the tunneling conductance — which is a signature of Andreev Bound States (ABS) at a surface of a d-wave superconductor — which splits at low temperature. This may confirm the existence of a surface state which breaks time-reversal symmetry. However, up to now, we have not seen any evidence of a coupling between Josephson current and the zero-energy ABS, predicted by Y. Tanaka and S. Kashiwaya
Inhomogeneous superconductivity induced in a ferromagnet by proximity effect
Planar tunneling spectroscopy reveals damped oscillations of the superconducting order parameter induced into a ferromagnetic thin film by the proximity effect. The oscillations are due to the finite momentum transfer provided to Cooper pairs by the splitting of the spin up and down bands in the ferromagnet. As a consequence, for negative values of the superconducting order parameter the tunneling spectra are capsized ("-state"). The oscillations' damping and period are set by the same length scale, which depends on the spin polarization