576 research outputs found

    A micro ultrasonic motor using a micro-machined cylindrical bulk PZT transducer

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    In this paper, a micro ultrasonic motor using a micro-machined bulk piezoelectric transducer is introduced. The cylindrical shaped bulk piezoelectric transducer, a diameter of 0.8 mm and a height of 2.2 mm, was developed as stator transducer for traveling wave type ultrasonic motor. The transducer was made of lead zirconate titanate (PZT) bulk ceramics, and formed by micro machining, Ni plating and laser beam cutting process. Using this stator transducer, we have fabricated a cylindrical micro ultrasonic motor, a diameter of 2.0 mm and a height of 5.9 mm. We have also evaluated some characteristics and succeeded in driving the micro ultrasonic motor.</p

    Assessment of myocardial perfusion by dynamic O-15-labeled water PET imaging: Validation of a new fast factor analysis

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    Background: Factor analysis (FA) is an established method for separating myocardium from blood pool by use of oxygen 15-labeled water and positron emission tomography for analyzing myocardial blood flow (MBF). Conventional FA methods generating images from sinograms (sinoFA) are time-consuming, whereas FA can be performed on the reconstructed images (reconFA) in a fraction of time. We validated the MBF values obtained by reconFA versus sinoFA. Methods and Results: In 23 volunteers (mean age, 26.6±3.4 years) MBF was calculated from sinoFA and reconFA and blindly reanalyzed 1 month later by the same observer. Intraobserver agreement and reconFA-versus-sinoFA agreement were assessed according to Bland and Altman (BA). Reproducibility proved excellent for global sinoFA (r=0.968; P<.001; BA limits, −0.617 to 0.676 mL·min−1·g−1) and slightly superior for reconFA (r=0.979; P<.001; BA limits, −0.538 to 0.558 mL·min−1·g−1), with wider limits of agreement for segmental MBF from sinoFA (r=0.777; P<.001; BA limits, −1.676 to 1.656 mL·min−1·g−1) and reconFA (r=0.844; P<.001; BA limits, −1.999 to 1.992 mL·min−1·g−1). In addition, sinoFA and reconFA showed excellent correlation (r=0.975, P<.001) and agreement (BA limits, −0.528 to 0.648 mL·min−1·g−1) for global and segmental values (r=0.955; P<.001; BA limits, −1.371 to 1.491 mL·min−1·g−1). Conclusions: Use of reconFA allows rapid and reliable quantitative MBF assessment with O-15-labeled wate

    Reduced 123I-BMIPP uptake implies decreased myocardial flow reserve in patients with chronic stable angina

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    Purpose Long-chain fatty acid (LCFA) is the main energy source for normal myocardium at rest, but in ischemic myocardium, the main energy substrate shifts from LCFA to glucose. 123I-BMIPP is a radiolabeled LCFA analog. In chronic stable angina without previous infarction, we suppose that reduced 123I-BMIPP uptake is related to the substrate shift in myocardium with decreased myocardial flow reserve (MFR). The purpose of this study was to relate 123I-BMIPP uptake to rest myocardial blood flow (MBF), hyperemic MBF, and MFR assessed with 15O-water positron emission tomography (PET). Methods We enrolled 21 patients with chronic stable angina without previous infarction, all of whom underwent 123I-BMIPP single-photon emission computed tomography (SPECT) and 15O-water PET. The left ventricle was divided into 13 segments. In each segment, rest MBF and hyperemic MBF were measured by PET. 123I-BMIPP uptake was evaluated as follows: score 0=normal, 1=slightly decreased uptake, 2=moderately decreased uptake, 3=severely decreased uptake, and 4=complete defect. 123I-BMIPP uptake was compared with rest MBF, hyperemic MBF, and MFR. Results The numbers of segments with 123I-BMIPP scores 0, 1, 2, 3, and 4 were 178, 40, 25, 24, and 0, respectively. The rest MBFs for scores 0, 1, 2, and 3 were 0.93±0.25, 0.86±0.21, 0.97±0.30, and 0.99±0.37 ml/min/g, respectively. The hyperemic MBFs for scores 0, 1, 2, and 3 were 2.76±1.29, 1.84±0.74, 1.37±0.39, and 1.08±0.40 ml/min/g, respectively. The MFRs for scores 0, 1, 2, and 3 were 3.01±1.38, 2.20±0.95, 1.44±0.22, and 1.10±0.26, respectively. As 123I-BMIPP uptake declined, hyperemic MBF and MFR decreased. Conclusion In chronic stable angina without previous infarction, reduced 123I-BMIPP uptake implies decreased MFR

    Dynamically Integrated Transport Approach for High-Energy Nuclear Collisions at High Baryon Density

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    To explore the structure of the QCD phase diagram in high baryon density domain, several high-energy nuclear collision experiments in a wide range of beam energies are currently performed or planned using many accelerator facilities. In these experiments search for a first-order phase transition and the QCD critical point is one of the most important topics. To find the signature of the phase transition, experimental data should be compared to appropriate dynamical models which quantitatively describe the process of the collisions. In this study we develop a new dynamical model on the basis of the non-equilibrium hadronic transport model JAM and 3+1D hydrodynamics. We show that the new model reproduce well the experimental beam-energy dependence of hadron yields and particle ratio by the partial thermalization of the system in our core-corona approach.Comment: 4 pages, 3 figures; contribution to the proceedings of the 8th International Conference on Quarks and Nuclear Physics (QNP2018), Tsukuba, November 13-17, 201

    Post-Fontan care based on hemodynamic characteristics, with special reference to the central venous pressure.

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    Changes in the hemodynamics of six patients having received Fontan-like operations were closely observed during the first 48 h after the operation. Catheterization studies and simultaneous angiocardiography were also performed before and after the operation. Hemodynamic derangement was particularly severe during the first 24 h postoperatively as indicated by a low cardiac output of less than 2.01/min/m2, which persisted in spite of very high central venous pressure. Furthermore, the central venous pressure needed to re-establish the circulation soon after the Fontan procedure significantly correlated with the angiocardiographically assessed preoperative size of distal pulmonary arteries. Accordingly, the preoperative evaluation of the distal pulmonary arterial size is very important, that provides a good guide-line for the degree of circulatory volume expansion necessary to elevate the central venous pressure and to sustain the circulation in the early postoperative period.</p
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