78 research outputs found

    Microwave integrated circuit for Josephson voltage standards

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    A microwave integrated circuit comprised of one or more Josephson junctions and short sections of microstrip or stripline transmission line is fabricated from thin layers of superconducting metal on a dielectric substrate. The short sections of transmission are combined to form the elements of the circuit and particularly, two microwave resonators. The Josephson junctions are located between the resonators and the impedance of the Josephson junctions forms part of the circuitry that couples the two resonators. The microwave integrated circuit has an application in Josephson voltage standards. In this application, the device is asymmetrically driven at a selected frequency (approximately equal to the resonance frequency of the resonators), and a d.c. bias is applied to the junction. By observing the current voltage characteristic of the junction, a precise voltage, proportional to the frequency of the microwave drive signal, is obtained

    Adult Height in Patients with Advanced CKD Requiring Renal Replacement Therapy during Childhood.

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    BACKGROUND AND OBJECTIVES: Growth and final height are of major concern in children with ESRD. This study sought to describe the distribution of adult height of patients who started renal replacement therapy (RRT) during childhood and to identify determinants of final height in a large cohort of RRT children. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: A total of 1612 patients from 20 European countries who started RRT before 19 years of age and reached final height between 1990 and 2011 were included. Linear regression analyses were performed to calculate adjusted mean final height SD score (SDS) and to investigate its potential determinants. RESULTS: The median final height SDS was -1.65 (median of 168 cm in boys and 155 cm in girls). Fifty-five percent of patients attained an adult height within the normal range. Adjusted for age at start of RRT and primary renal diseases, final height increased significantly over time from -2.06 SDS in children who reached adulthood in 1990-1995 to -1.33 SDS among those reaching adulthood in 2006-2011. Older age at start of RRT, more recent period of start of RRT, cumulative percentage time on a functioning graft, and greater height SDS at initiation of RRT were independently associated with a higher final height SDS. Patients with congenital anomalies of the kidney and urinary tract and metabolic disorders had a lower final height than those with other primary renal diseases. CONCLUSIONS: Although final height remains suboptimal in children with ESRD, it has consistently improved over time

    Interactions in small systems of coupled Josephson junctions at microwave frequencies

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    A major factor in the practical utilization of any Josephson device for microwave and higher frequency applications (such as the generation and detection of electromagnetic radiation) is the success with which the junction device can be coupled to an external transmission line. As part of an experimental investigation of the electrodynamics of small arrays of Josephson tunnel junctions, the properties of the coherent radiation emitted both by individual junctions and by coupled junction systems have been studied at frequencies between 2 and 12 GHz. Near 9 GHz, more than 10-9 W of coherent radiation has been detected from a single Pb-Pb oxide-Pb junction coupled via waveguide. The development of thin film devices in which the tunnel junctions form part of a microstrip line have made it feasible to observe directly (in a single device) the radiation emitted both at the fundamental geometrical frequency and at the low order harmonics. The observed temperature dependence of the junction cavity Q indicate the low temperature losses are primarily due to cavity loading of the external transmission line.La manière de coupler un dispositif Josephson à une ligne de transmission a une très grande importance pour les applications hyperfréquences (génération ou détection de rayonnement électromagnétique). Dans la bande 2-12 GHz, nous avons étudié les propriétés électrodynamiques du rayonnement cohérent, émis soit par des jonctions individuelles, soit par un ensemble de jonctions couplées. Nous avons détecté un niveau supérieur à 10-9 W de rayonnement cohérent à 9 GHz, provenant d'une seule jonction Pb-oxyde Pb-Pb, couplée à un guide d'onde. Grâce au développement des dispositifs à couche mince, dans lequel les jonctions tunnels font partie d'une ligne microstrip, on a pu observer directement (avec un seul dispositif) le rayonnement émis à la fois à la fréquence fondamentale et aux premiers harmoniques. A basse température, on montre que les pertes de la cavité sont dues essentiellement à la ligne de transmission

    Identification of two highly antigenic epitope markers predicting multiple sclerosis in optic neuritis patients

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    Background: Optic neuritis (ON) can occur as an isolated episode or will develop to multiple sclerosis (MS) a chronic autoimmune disease. What predicts ON progression to MS remains poorly understood. Methods: We characterised the antibody epitope repertoire in three independent clinical cohorts (discovery (n = 62), validation (n = 20) and external cohort (n = 421)) using mimotope variation analysis (MVA), a next generation phage display technology to identify epitopes that associate with prognosis of ON. Findings: We observed distinct epitope profiles for ON, MS and the controls, whereas epitope repertoires of sera and CSF were highly similar. Two unique and highly immunogenic epitopes A and B were detected in subjects with ON progressing to MS. These epitopes A and B were strongly associated with herpesviral antigens (VCA p18 of Epstein-Barr virus (EBV); gB of Cytomegalovirus (CMV)). ROC addressed 75% of MS subjects with ON onset correctly (at 75% sensitivity and 74.22% specificity) based on the two-epitope biomarker analysis. Interpretation: This is the first report on epitope diagnostics for MS employing the unbiased strategy of MVA for identification of novel immunological features of disease. (C) 2021 The Authors. Published by Elsevier B.V.Peer reviewe
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