192 research outputs found

    Dominant Model-Parameter Determination for the Analysis of Current Imbalance Across Paralleled Power Transistors

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    In this article, we propose a new sensitivity-based analytical equation, the nn -devices forward propagation of variance (NFPV). Using the proposed NFPV equation, the dominant device model parameters— essential for accurate analysis of energy-loss variation due to the current imbalance across paralleled power transistors from statistical parameter variations—are efficiently determined. The proposed method with the NFPV equation is faster than conventional methods that use Monte Carlo simulation. We conducted experimental validation using the measured current–voltage characteristics of commercially available 100 silicon mosfet s and 300 silicon carbide mosfet s. The results show that the proposed NFPV-based method efficiently finds the dominant device model parameters, which are sufficient and necessary to reproduce the energy-loss variation, regardless of the number of parallel transistors. The results also show that the determined dominant device model parameters are valid under practical situations, such as uneven parasitic inductances and device temperature imbalance among paralleled transistors. The proposed method determines the dominant device model parameters 9.33× faster than the conventional method while maintaining the same accuracy. Additionally, we demonstrate that, compared with the conventional method, an increase in the number of candidate statistical model parameters increases the efficiency of the proposed method

    Mesoscopic Multimodal Imaging Provides New Insight to Tumor Tissue Evaluation : An Example of Macrophage Imaging of Hepatic Tumor using Organosilica Nanoparticles

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    Multimodal imaging using novel multifunctional nanoparticles provides new approach to biomedical field. Thiol-organosilica nanoparticles containing iron oxide magnetic nanoparticles (MNPs) and rhodamine B (thiol OS-MNP/Rho) were applied to multimodal imaging of hepatic tumor of Long−Evans Cinnamon (LEC) rat. The magnetic resonance imaging (MRI) of LEC rats revealed tumors in the liver clearly and semi-quantitatively due to a labeling of macrophages in liver. The fluorescent imaging (FI) showed abnormal fluorescent patterns of the liver at the mesoscopic level that was between macroscopic and microscopic level. We performed correlation analysis between optical imaging including FI and MRI. We found that the labeled macrophages located specific area in the tumor tissue and influenced the tumor size on MRI. In addition histological observation showed the labeled macrophages related specific tissue in the pathological region. We demonstrated a new approach to evaluate tumor tissue at the macroscopic and microscopic level as well as mesoscopic level using multimodal imaging

    ヒセンケイ キョウメイ ゲンショウ オ リヨウ シタ チョウ イオン ドウデンタイ ノ ブツセイ ソクテイ

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    Lithium transition metal oxides are attractive as the positive electrode of secondary battery. In this study, the phonon-echo measurements have been performed to study Li+ ionic motion in piezoelectric LiNbO3 powder. The phonon-echo is generated by propagating waves coupling through the anharmonicity of lattice vibrations. The decay time of the echo, T2 is connected with the internal friction within each particle, which is functional as an acoustic oscillator. The decrease in T2 observed above 800 K in the polycrystalline powder is explained in terms of a Debye-type relaxation model based on Li+ ionic motion. The activation energy is estimated as about 0.93 eV, which is in good agreement with those reported from NMR and ionic conductivity measurements. The present study indicates that the phonon-echo measurement is useful to elucidate the ionic motion in ionic conductors

    Clinical Performance of a Salivary Amylase Activity Monitor During Hemodialysis Treatment

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    The hemodialysis procedure is thought to be a physical stressor in the majority of hemodialyzed patients. Previous studies suggest that elevated salivary amylase level may correlate with increased plasma norepinephrine level under psychological and physical stress conditions. In this study, we investigated biological stress reactivity during hemodialysis treatment using salivary amylase activity as a biomarker. Seven patients (male/female = 5/2, age: 67.7+/−5.9 years) who had been receiving regular 4 h hemodialysis were recruited. Salivary amylase activity was measured using a portable analyzer every hour during the hemodialysis session. Salivary amylase activity was shown to be relatively stable and constant throughout hemodialysis, whereas there were significant changes in systolic blood pressure and pulse rate associated with blood volume reduction. Our results show that hemodialysis treatment per se dose not affect salivary amylase activity

    Coactosin Promotes F-Actin Protrusion in Growth Cones Under Cofilin-Related Signaling Pathway

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    During brain development, axon outgrowth and its subsequent pathfinding are reliant on a highly motile growth cone located at the tip of the axon. Actin polymerization that is regulated by actin-depolymerizing factors homology (ADF-H) domain-containing family drives the formation of lamellipodia and filopodia at the leading edge of growth cones for axon guidance. However, the precise localization and function of ADF-H domain-containing proteins involved in axon extension and retraction remain unclear. We have previously shown that transcripts and proteins of coactosin-like protein 1 (COTL1), an ADF-H domain-containing protein, are observed in neurites and axons in chick embryos. Coactosin overexpression analysis revealed that this protein was localized to axonal growth cones and involved in axon extension in the midbrain. We further examined the specific distribution of coactosin and cofilin within the growth cone using superresolution microscopy, structured illumination microscopy, which overcomes the optical diffraction limitation and is suitable to the analysis of cellular dynamic movements. We found that coactosin was tightly associated with F-actin bundles at the growth cones and that coactosin overexpression promoted the expansion of lamellipodia and extension of growth cones. Coactosin knockdown in oculomotor neurons resulted in an increase in the levels of the inactive, phosphorylated form of cofilin and dysregulation of actin polymerization and axonal elongation, which suggests that coactosin promoted axonal growth in a cofilin-dependent manner. Indeed, the application of a dominant-negative form of LIMK1, a downstream effector of GTPases, reversed the effect of coactosin knockdown on axonal growth by enhancing cofilin activity. Combined, our results indicate that coactosin functions promote the assembly of protrusive actin filament arrays at the leading edge for growth cone motility

    Diffuse Intervertebral Disk Calcification in a Patient with Rheumatoid Arthritis

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    A patient with seronegative rheumatoid arthritis (RA) who presented with intervertebral disk calcification (IDC) of several thoracic and lumbar intervertebral disks is herein described. There was no evidence of any other coexisting diseases such as ochronosis and hemochromatosis, but a remarkable degree of polyclonal hypergammaglobulinemia was observed as a notable finding. Although the appearance of IDC on T1-weighted images on magnetic resonance is controversal, no increased signal intensity was observed in our patient. To the best of our knowledge, this is the first report of IDC in RA

    Molecular Outflows From the Protocluster, Serpens South

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    We present the results of CO (J=32J=3-2) and HCO+^+ (J=43J=4-3) mapping observations toward a nearby embedded cluster, Serpens South, using the ASTE 10 m telescope. Our CO (J=32J=3-2) map reveals that many outflows are crowded in the dense cluster-forming clump that can be recognized as a HCO+^+ clump with a size of \sim 0.2 pc and mass of \sim 80 M_\odot. The clump contains several subfragments with sizes of \sim 0.05 pc. By comparing the CO (J=32J=3-2) map with the 1.1 mm dust continuum image taken by AzTEC on ASTE, we find that the spatial extents of the outflow lobes are sometimes anti-correlated with the distribution of the dense gas and some of the outflow lobes apparently collide with the dense gas. The total outflow mass, momentum, and energy are estimated at 0.6 MM_\odot, 8 MM_\odot km s1^{-1}, and 64 MM_\odot km2^2 s2^{-2}, respectively. The energy injection rate due to the outflows is comparable to the turbulence dissipation rate in the clump, implying that the protostellar outflows can maintain the supersonic turbulence in this region. The total outflow energy seems only about 10 percent the clump gravitational energy. We conclude that the current outflow activity is not enough to destroy the whole cluster-forming clump, and therefore star formation is likely to continue for several or many local dynamical times.Comment: 25 pages, 16 figures, accepted for publication in Ap
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