264 research outputs found

    Novel insights into bi-articular muscle actions gained from high-density EMG

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    Biarticular muscles have traditionally been considered to exhibit homogeneous neuromuscular activation. The regional activation of biarticular muscles, as revealed from high-density surface electromyograms, seems however to discredit this notion. We thus hypothesize the regional activation of biarticular muscles may contribute to different actions about the joints they span. We then discuss the mechanistic basis and methodological implications underpinning our hypothesis

    Impact of hydrogen isotope species on microinstabilities in helical plasmas

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    The impact of isotope ion mass on ion-scale and electron-scale microinstabilities such as ion temperature gradient (ITG) mode, trapped electron mode (TEM), and electron temperature gradient (ETG) mode in helical plasmas are investigated by using gyrokinetic Vlasov simulations with a hydrogen isotope and real-mass kinetic electrons. Comprehensive scans for the equilibrium parameters and magnetic configurations clarify the transition from ITG mode to TEM instability, where a significant TEM enhancement is revealed in the case of inward-shifted plasma compared to that in the standard configuration. It is elucidated that the ion-mass dependence on the ratio of the electron–ion collision frequency to the ion transit one, i.e. νei/ωti(mi/me)1/2{{\nu}_{\text{ei}}}/{{\omega}_{\text{ti}}}\propto {{\left({{m}_{\text{i}}}/{{m}_{\text{e}}}\right)}^{1/2}} , leads to a stabilization of the TEM for heavier isotope ions. The ITG growth rate indicates a gyro-Bohm-like ion-mass dependence, where the mixing-length estimate of diffusivity yields γ/k2mi1/2\gamma /k_{\bot}^{2}\propto m_{\text{i}}^{1/2} . On the other hand, a weak isotope dependence of the ETG growth rate is identified. A collisionality scan also reveals that the TEM stabilization by the isotope ions becomes more significant for relatively higher collisionality in a banana regime

    Isotope Effects on Trapped-Electron-Mode Driven Turbulence and Zonal Flows in Helical and Tokamak Plasmas

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    Impacts of isotope ion mass on trapped-electron-mode (TEM)-driven turbulence and zonal flows in magnetically confined fusion plasmas are investigated. Gyrokinetic simulations of TEM-driven turbulence in three-dimensional magnetic configuration of helical plasmas with hydrogen isotope ions and real-mass kinetic electrons are realized for the first time, and the linear and the nonlinear nature of the isotope and collisional effects on the turbulent transport and zonal-flow generation are clarified. It is newly found that combined effects of the collisional TEM stabilization by the isotope ions and the associated increase in the impacts of the steady zonal flows at the near-marginal linear stability lead to the significant transport reduction with the opposite ion mass dependence in comparison to the conventional gyro-Bohm scaling. The universal nature of the isotope effects on the TEM-driven turbulence and zonal flows is verified for a wide variety of toroidal plasmas, e.g., axisymmetric tokamak and non-axisymmetric helical or stellarator systems

    Conservation laws for collisional and turbulent transport processes in toroidal plasmas with large mean flows

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    A novel gyrokinetic formulation is presented by including collisional effects into the Lagrangian variational principle to yield the governing equations for background and turbulent electromagnetic fields and gyrocenter distribution functions, which can simultaneously describe classical, neoclassical, and turbulent transport processes in toroidal plasmas with large toroidal flows on the order of the ion thermal velocity. Noether\u27s theorem modified for collisional systems and the collision operator given in terms of Poisson brackets are applied to derivation of the particle, energy, and toroidal momentum balance equations in the conservative forms, which are desirable properties for long-time global transport simulation

    Protein S100-A7 derived from digested dentin is a critical molecule for dentin pulp regeneration

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    Dentin consists of inorganic hard tissue and organic dentin matrix components (DMCs). Various kinds of bioactive molecules are included in DMCs and some of them can be released after digestion by endogenous matrix metalloproteinases (MMPs) in the caries region. Digested DMCs induced by MMP20 have been reported to promote pulpal wound healing processes, but the released critical molecules responsible for this phenomenon are unclear. Here, we identified protein S100-A7 as a critical molecule for pulpal healing in digested DMCs by comprehensive proteomic approaches and following pulp capping experiments in rat molars. In addition, immunohistochemical results indicated the specific distribution of S100-A7 and receptor for advanced glycation end-products (RAGE) as receptor for S100-A7 in the early stage of the pulpal healing process, and following accumulation of CD146-positive stem cells in wounded pulp. Our findings indicate that protein S100-A7 released from dentin by MMP20 might play a key role in dentin pulp regeneration

    香港帰来の日本人観光団に発生した腸炎ビブリオ食中毒

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    In October 1968, outbreaks of acute gastroenteritis occurred among five Japanese sightseeing groups during their stay in Hong Kong and/or on their homeward return flight. Bacteriologic examination of fecal specimens obtained from 62 of 144 tour members of the third group led to the isolation of 14 Vibrio parahaemolyticus strains with hemolytic activity. No enteric pathogens were isolated from three patients of the fifth party who also had symptoms. As ill persons were rare in the other groups and those who had diarrhea already recovered at the time of the inspection, no fecal examination was performed on them. The history of food consumption suggested that raw sea food served in restaurants in Hong Kong may have been the vehicle of infective agent.昭和43年10月,日本人観光団5団体に,香港に滞在中あるいは引きつづき航空機で帰国中に急性胃腸炎が発生した.東京空港検疫所で帰着時まだ軽微な症状を示していた第3群144名中の62名について検便を行ない,うち14名から神奈川現象陽性腸炎ビブリオを検出した.第5群にも3名の有症者がいたがこれからは病原細菌を検出し得なかった.原因食は香港の水上レストランなどで摂った生の海産物と推定された.この事例の考察にあたり,神奈川現象陽性の本菌が東南アジアの港湾泥土から検出されたこと,および日本以外の国々での本菌ないしその類似菌による食中毒発生例が文献によって概観された

    Influence of myopotential interference on the Wavelet discrimination algorithm in implantable cardioverter-defibrillator

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    Background: Wavelet is a morphology-based algorithm for detecting ventricular tachycardia. The electrogram (EGM) source of the Wavelet algorithm is nominally programmed with the Can-RV coil configuration, which records a far-field ventricular potential. Therefore, it may be influenced by myopotential interference. Methods: We performed a retrospective review of 40 outpatients who had an implantable cardioverter-defibrillator (LCD) with the Wavelet algorithm. The percent-match score of the Wavelet algorithm was measured during the isometric chest press by pressing the palms together. We classified patients with percent-match scores below 70% due to myopotential interference as positive morphology change, and those with 70% or more as negative morphology change. Stored episodes of tachycardia were evaluated during the follow-up. Results: The number of patients in the positive morphology change group was 22 (55%). Amplitude of the Can-RV coil EGM was lower in the positive morphology change group compared to that in the negative group (3.9 +/- 1.3 mV vs. 7.4 +/- 1.6 mV, P=0.0015). The cut-off value of the Can-RV coil EGM was 5 mV (area under curve, 0.89). Inappropriate detections caused by myopotential interference occurred in two patients (5%) during a mean follow-up period of 49 months, and one of them received an inappropriate LCD shock. These patients had exhibited positive morphology change. Conclusions: The Wavelet algorithm is influenced by myopotential interference when the Can-RV coil EGM is less than 5 mV

    Modeling of turbulent particle and heat transport in helical plasmas based on gyrokinetic analysis

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    The particle and heat transport driven by the ion temperature gradient instability in helical plasmas is investigated by the gyrokinetic analysis taking into account the kinetic electron response. High and low ion temperature plasma cases for the discharge in the Large Helical Device (LHD) are studied. Two types of transport models with a lower computational cost to reproduce the nonlinear gyrokinetic simulation results within allowable errors are presented for application in quick transport analyses. The turbulent electron and ion heat diffusivity models are given in terms of the linear growth rate and the characteristic quantity for the linear response of zonal flows, while the model of the effective particle diffusivity is not obtained for the flattened density profile observed in the LHD. The quasilinear flux model is also shown for the heat transport. The quasilinear flux models for the energy fluxes are found to reproduce the nonlinear simulation results at the accuracy similar to that of the heat diffusivity models. In addition, the quasilinear particle flux model, which is applicable to the transport analysis for LHD plasmas, is constructed. These turbulent reduced models enable coupling to the other simulation in the integrated codes for the LHD
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