232 research outputs found

    Localised surface plasmon resonance inducing cooperative Jahn–Teller effect for crystal phase-change in a nanocrystal

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    結晶中の電子の集団的な運動が原子を動かすプラズモン誘起原子変位を初めて発見 --見えない光学センサーなど新技術の実現に期待--. 京都大学プレスリリース. 2023-08-01.The Jahn–Teller effect, a phase transition phenomenon involving the spontaneous breakdown of symmetry in molecules and crystals, causes important physical and chemical changes that affect various fields of science. In this study, we discovered that localised surface plasmon resonance (LSPR) induced the cooperative Jahn–Teller effect in covellite CuS nanocrystals (NCs), causing metastable displacive ion movements. Electron diffraction measurements under photo illumination, ultrafast time-resolved electron diffraction analyses, and theoretical calculations of semiconductive plasmonic CuS NCs showed that metastable displacive ion movements due to the LSPR-induced cooperative Jahn–Teller effect delayed the relaxation of LSPR in the microsecond region. Furthermore, the displacive ion movements caused photo-switching of the conductivity in CuS NC films at room temperature (22 °C), such as in transparent variable resistance infrared sensors. This study pushes the limits of plasmonics from tentative control of collective oscillation to metastable crystal structure manipulation

    Characteristics of systolic and diastolic potentials recorded in the left interventricular septum in verapamil-sensitive left ventricular tachycardia

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    We studied the electrophysiological characteristics of systolic (SP) and diastolic (DP) potentials recorded during sinus rhythm (SR) in the left interventricular septum of a 27 year-old woman presenting with verapamil-sensitive idiopathic left ventricular tachycardia (VT). During SR, and during VT, SP was activated from ventricular base-to-apex, and DP from apex-to-base. SP and DP were both detected at the site of successful ablation during SR, whereas during VT, DP was detected away from the earliest activation site. Thus, SP apparently reflected a critical component of the reentrant circuit, while DP reflected the activation of a bystander pathway

    Development of catheter-type tactile sensor composed of polyvinylidene fluoride (PVDF) film

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    To achieve quantitative palpation in vivo, we developed a catheter-type tactile sensor composed of a polyvinylidene fluoride film for minimally invasive surgery. We evaluated the fundamental performance of the prototype sensor by a weight-drop test. We also measured the output of the prototype sensor as it was inserted into a blood vessel model with shapes mimicking lesions. The ø2-mm sensor passed easily into the blood vessel model with lesion-like shapes. Sensor outputs corresponded to the shape of the inner wall of the blood vessel model, making it possible to determine the position of a protrusion and the convexity interval of a rough surface by filtering and frequency analysis of the output

    Irregular atrial flutter following pulmonary vein isolation for persistent atrial fibrillation

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    AbstractA 65-year-old man with a history of refractory paroxysmal atrial fibrillation (AF) underwent catheter ablation for persistent AF lasting 2 months. AF was not terminated after complete isolation of the 4 pulmonary veins (PV). Instead, it was transformed to a sustained atrial tachyarrhythmia with beat-to-beat variability in the atrial cycle length. A 12-lead electrocardiogram during tachycardia showed negative flutter-like waves in the inferior leads. Entrainment pacing along the tricuspid annulus confirmed the diagnosis of irregular cavotricuspid isthmus (CTI)-dependent typical atrial flutter (AFL). Linear ablation of the CTI terminated AFL and restored sinus rhythm

    Typical atrial flutter with atypical flutter wave morphology due to abnormal interatrial conduction

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    We report a case of typical counterclockwise atrial flutter (AFL) with conduction block from right to left atrium along the coronary sinus (CS) musculature, confirmed by discontinuous CS activation sequence during pacing near the ostium and differential right atrial pacing. AFL was associated with an atypical flutter wave morphology, due to the detour of the activation wavefront from right to left atrium via alternate interatrial electrical connections, such as Bachmann’s bundle, the interatrial septum, or both. (Cardiol J 2011; 18, 4: 450–453

    \mu-\tau Symmetry and Maximal CP Violation

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    We argue the possibility that a real part of a flavor neutrino mass matrix only respects a mu-tau symmetry. This possibility is shown to be extended to more general case with a phase parameter \theta, where the mu-tau symmetric part has a phase of \theta/2. This texture shows maximal CP violation and no Majorana CP violation.Comment: 5 pages, version to appear in Phys. Lett.
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