14 research outputs found

    Different regimes of nucleation of superconductivity in mesoscopic superconductor/ferromagnet hybrids

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    The competition between two regimes of the nucleation of superconductivity is investigated experimentally and theoretically in a mesoscopic disk-shaped superconductor/ferromagnet hybrid. By changing the magnetic state of a multilayered Co/Pt disk one can reversibly affect the magnetic-field dependence of the critical temperature T(c)(H) of an Al layer. We demonstrate that an enhancement of the magnetic field near the edge of the out-of-plane magnetized disk either stimulates the nucleation of superconductivity at the disk perimeter due to the field compensation effect or prevents it due to edge magnetic barrier (for relatively low parallel to H parallel to values). As a consequence, the presence of such magnetic-field pattern makes it possible to eliminate boundary effects for mesoscopic superconducting samples. Switching from one nucleation regime to another while sweeping H leads to an abrupt change of the slope of the T(c)(H) envelope

    Critical field enhancement in hybrid superconductor/ferromagnet mesoscopic disks

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    We investigated experimentally the nucleation of superconductivity in a mesoscopic hybrid structure, consisting of a thin superconducting disk covered with a ferromagnetic layer with an in-plane magnetic moment. By applying a magnetic field in the plane of the structure, the remanent magnetic state of the ferromagnet can be switched from a flux-closure state where field lines are confined inside the ferromagnet to a polarized state with nonzero stray fields at the edges. This change in the magnetic state causes a drastic modification on the superconductor/normal-state phase boundary of the hybrid sample. In the polarized state a re-entrant transition line and a strong broadening of the phase boundary are observed

    Infections Caused By Kingella-kingae - Report of 4 Cases and Review

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    Kingella kingae, formerly known as Moraxella kingae, is a fastidious, non-motile, coccobacillary, fermentative Gram-negative rod that has been chiefly associated with two types of infections in man: Bone and joint infections, and endocarditis. We describe four patients with K. kingae infections, one with septicaemia, two with endocarditis, and one with osteoarthritis. The current literature on infections with K. kingae is reviewed

    Programmed intermittent epidural bolus vs. patient-controlled epidural analgesia for maintenance of labour analgesia: a two-centre, double-blind, randomised study

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    The programmed intermittent epidural bolus technique has shown superiority to continuous epidural infusion techniques, with or without patient-controlled epidural analgesia for pain relief, reduced motor block and patient satisfaction. Many institutions still use patient-controlled epidural analgesia without a background infusion, and a comparative study between programmed intermittent epidural bolus and patient-controlled epidural analgesia without a background infusion has not yet been performed. We performed a randomised, two-centre, double-blind, controlled trial of these two techniques. The primary outcome was the incidence of breakthrough pain requiring a top-up dose by an anaesthetist. Secondary outcomes included: motor block; pain scores; patient satisfaction; local anaesthetic consumption; and obstetric and neonatal outcomes. We recruited 130 nulliparous women who received initial spinal analgesia, and then epidural analgesia was initiated and maintained with either programmed intermittent epidural bolus or patient-controlled epidural analgesia using ropivacaine 0.12% with sufentanil 0.75 µg·ml-1 . The programmed intermittent epidural bolus group had a programmed bolus of 10 ml every hour, with on-demand patient-controlled epidural analgesia boluses of 5 ml with a 20 min lockout, and the patient-controlled epidural analgesia group had a 5 ml bolus with a 12 min lockout interval; the potential maximum volume per hour was the same in both groups. The patients in the programmed intermittent epidural bolus group had less frequent breakthrough pain compared with the patient-controlled epidural analgesia group, 7 (10.9%) vs. 38 (62.3%; p < 0.0001), respectively. There was a significant difference in motor block (modified Bromage score ≤ 4) frequency between groups, programmed intermittent epidural bolus group 1 (1.6%) vs. patient-controlled epidural analgesia group 8 (13.1%); p = 0.015. The programmed intermittent epidural bolus group had greater local anaesthetic consumption with fewer patient-controlled epidural analgesia boluses. Patient satisfaction scores and obstetric or neonatal outcomes were not different between groups. In conclusion, we found that a programmed intermittent epidural bolus technique using 10 ml programmed boluses and 5 ml patient-controlled epidural analgesia boluses was superior to a patient-controlled epidural analgesia technique using 5 ml boluses and no background infusion.status: publishe
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