112 research outputs found

    Muscle damage indicated by maximal voluntary contraction strength changes from immediately to 1 day after eccentric exercise of the knee extensors

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    The present study examined if the magnitude of changes in indirect muscle damage markers could be predicted by maximal voluntary isometric contraction (MVIC) torque changes from immediately to 1 day after eccentric exercise. Twenty-eight young men performed 100 maximal isokinetic (60°/s) eccentric contractions of the knee extensors. MVIC torque, potentiated doublet torque, voluntary activation (VA) during MVIC, shear modulus of rectus femoris (RF), vastus medialis and lateralis, and muscle soreness of these muscles were measured before, immediately after, and 1–3 days post-exercise. Based on the recovery rate of the MVIC torque from immediately to 1-day post-exercise, the participants were placed to a recovery group that showed an increase in the MVIC torque (11.3–79.9%, n = 15) or a no-recovery group that showed no recovery (−71.9 to 0%, n = 13). No significant difference in MVIC torque decrease immediately post-exercise was found between the recovery (−33 ± 12%) and no-recovery (−32 ± 9%) groups. At 1–3 days, changes in MVIC torque (−40 to −26% vs. −22 to −12%), potentiated doublet torque (−37 to −22% vs. −20 to −9%), and proximal RF shear modulus (29–34% vs. 8–15%) were greater (p \u3c 0.05) for the no-recovery than recovery group. No significant group differences were found for muscle soreness. The recovery rate of MVIC torque was correlated (p \u3c 0.05) with the change in MVIC torque from baseline to 2 (r = 0.624) or 3 days post-exercise (r = 0.526), or peak change in potentiated doublet torque at 1–3 days post-exercise from baseline (r = 0.691), but not correlated with the changes in other dependent variables. These results suggest that the recovery rate of MVIC torque predicts changes in neuromuscular function but not muscle soreness and stiffness following eccentric exercise of the knee extensors

    Relation of leg phase angle from bioelectrical impedance analysis with voluntary and evoked contractile properties of the plantar flexors

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    Introduction: Bioelectrical impedance analysis (BIA) can noninvasively and quickly assess electrical properties of the body, such as the phase angle. Phase angle is regarded as the quantity and/or quality of skeletal muscle and is associated with exercise performance, such as jump height and walking speed. Although the phase angle derived from BIA is assumed to be a useful way to assess muscle function, the relationship between the phase angle and neuromuscular properties has not been fully investigated. The purpose of this study was to investigate the association of phase angle with voluntary and evoked contractile properties in 60 adults (age, 21–83 years; 30 females and 30 males).Methods: The phase angle of the right leg at 50 kHz was evaluated using BIA. The twitch contractile properties (peak twitch torque [PTtwitch], rate of twitch torque development [RTDtwitch], and time-to-PTtwitch [TPTtwitch]) of the plantar flexors were measured using tibial nerve electrical stimulation. Maximal voluntary isometric contractions (MVICs) were performed to measure the maximal muscle strength and explosive muscle strength, from which the peak MVIC torque (PTMVIC) and rate of torque development (RTD) over a time interval of 0–200 ms were assessed, respectively. The root mean square (RMS) values of electromyographic (EMG) activity during the PTMVIC and RTD measurements (EMG-RMSMVIC and EMG-RMSRTD, respectively) were calculated. The RTD and EMG-RMSRTD were normalized using PTMVIC and EMG-RMSMVIC, respectively.Results and discussion: Phase angle significantly correlated with twitch contractile properties (|r| ≥ 0.444, p < 0.001), PTMVIC (r = 0.532, p < 0.001), and RTD (r = 0.514, p < 0.001), but not with normalized RTD (r = 0.242, p = 0.065) or normalized EMG-RMSRTD (r = −0.055, p = 0.676). When comparing measurement variables between the low- and high-phase angle groups while controlling for sex and age effects, the high-phase angle group showed greater PTtwitch, RTDtwitch, PTMVIC, and RTD (p < 0.001) and shorter TPTtwitch (p < 0.001) but not normalized RTD (p = 0.184) or normalized EMG-RMSRTD (p = 0.317). These results suggest that the leg phase angle can be an indicator of voluntary and evoked muscle contractile properties but not the neuromuscular activity of the plantar flexors, irrespective of sex and age

    Unveiling charge dynamics of visible light absorbing oxysulfide for efficient overall water splitting

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    Oxysulfide semiconductor, Y2Ti2O5S2, has recently discovered its exciting potential for visible-light-induced overall water splitting, and therefore, imperatively requires the probing of unknown fundamental charge loss pathways to engineer the photoactivity enhancement. Herein, transient diffuse reflectance spectroscopy measurements are coupled with theoretical calculations to unveil the nanosecond to microsecond time range dynamics of the photogenerated charge carriers. In early nanosecond range, the pump-fluence-dependent decay dynamics of the absorption signal is originated from the bimolecular recombination of mobile charge carriers, in contrast, the power-law decay kinetics in late microsecond range is dominated by hole detrapping from exponential tail trap states of valence band. A well-calibrated theoretical model estimates various efficiency limiting material parameters like recombination rate constant, n-type doping density and tail-states parameters. Compared to metal oxides, longer effective carrier lifetime ~6 ns is demonstrated. Different design routes are proposed to realize efficiency beyond 10% for commercial solar-to-hydrogen production from oxysulfide photocatalysts

    Development and Performance of Kyoto's X-ray Astronomical SOI pixel (SOIPIX) sensor

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    We have been developing monolithic active pixel sensors, known as Kyoto's X-ray SOIPIXs, based on the CMOS SOI (silicon-on-insulator) technology for next-generation X-ray astronomy satellites. The event trigger output function implemented in each pixel offers microsecond time resolution and enables reduction of the non-X-ray background that dominates the high X-ray energy band above 5--10 keV. A fully depleted SOI with a thick depletion layer and back illumination offers wide band coverage of 0.3--40 keV. Here, we report recent progress in the X-ray SOIPIX development. In this study, we achieved an energy resolution of 300~eV (FWHM) at 6~keV and a read-out noise of 33~e- (rms) in the frame readout mode, which allows us to clearly resolve Mn-Kα\alpha and Kβ\beta. Moreover, we produced a fully depleted layer with a thickness of 500 μm500~{\rm \mu m}. The event-driven readout mode has already been successfully demonstrated.Comment: 7pages, 12figures, SPIE Astronomical Telescopes and Instrumentation 2014, Montreal, Quebec, Canada. appears as Proc. SPIE 9147, Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ra

    NMR Characterization of the Interaction of the Endonuclease Domain of MutL with Divalent Metal Ions and ATP

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    Mizushima R, Kim JY, Suetake I, Tanaka H, Takai T, et al. (2014) NMR Characterization of the Interaction of the Endonuclease Domain of MutL withDivalent Metal Ions and ATP. PLoS ONE 9(6): e98554. doi:10.1371/journal.pone.009855

    NMR Characterization of the Interaction of the Endonuclease Domain of MutL with Divalent Metal Ions and ATP

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    Mizushima R, Kim JY, Suetake I, Tanaka H, Takai T, et al. (2014) NMR Characterization of the Interaction of the Endonuclease Domain of MutL withDivalent Metal Ions and ATP. PLoS ONE 9(6): e98554. doi:10.1371/journal.pone.009855

    Rapid Formation of Cerebral Microbleeds after Carotid Artery Stenting

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    Background: Recent studies reported that cerebral microbleeds (CMBs), i.e. small areas of signal loss on T2*-weighted gradient-echo (GE) imaging, could develop rapidly after acute ischemic stroke. We hypothesized that CMBs rapidly emerge after carotid artery stenting (CAS). Objective: We investigated the frequency of and predisposing factors for CMBs after CAS. Methods: We retrospectively examined MRI before and after CAS in 88 consecutive patients (average age: 71.7 ± 7.2 years, average rates of carotid stenosis: 72.6 ± 12.8%) who underwent CAS for carotid artery stenosis between March 1, 2009, and September 30, 2010. We defined new CMBs as signal losses that newly appeared on the follow-up GE. We examined the association of new CMBs with demographics, risk factors, and baseline MBs. Results: Among 88 patients, 18 (20.5%) had CMBs initially, and 7 (8.0%) developed new CMBs right after CAS. New CMBs appeared on the same side of CAS in all of the 7 patients. New CMBs appeared significantly more frequently in the CMB-positive group than in the CMB-negative one (22% vs. 4%, p = 0.03) on the pre-CAS MRI. Multivariate analysis also revealed that the presence of CMBs before CAS was an independent predictor of new development of CMBs after CAS (odds ratio: 8.09, 95% confidence interval: 1.39–47.1). Conclusion: CMBs can develop rapidly after CAS, especially in patients with pre-existing CMBs. Since the existence of CMBs prior to CAS suggests a latent vascular damage which is vulnerable to hemodynamic stress following CAS, particular attention should be paid to the prevention of intracerebral hemorrhage due to hyperperfusion after CAS

    Tumor-Infiltrating Lymphocytes and Macrophages as a Significant Prognostic Factor in Biliary Tract Cancer

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    Background: The impact of tumor-infiltrating lymphocytes (TILs) and tumor-associated macrophages (TAMs) on the prognosis of biliary tract cancer (BTC) is not completely understood. Therefore, in our study, we investigated the effects of the various immune cells infiltration in tumor microenvironment (TME). Methods: A total of 130 patients with BTC who underwent surgical treatment at our institution were enrolled in this study. We retrospectively evaluated TILs and TAMs with immunohistochemical staining. Results: With CD8-high, CD4-high, FOXP3-high, and CD68-low in TME as one factor, we calculated Immunoscore according to the number of factors. The high Immunoscore group showed significantly superior overall survival (OS) and recurrence-free survival (RFS) than the low Immunoscore group (median OS, 60.8 vs. 26.4 months, p = 0.001; median RFS not reached vs. 17.2 months, p \u3c 0.001). Also, high Immunoscore was an independent good prognostic factor for OS and RFS (hazards ratio 2.05 and 2.41 and p = 0.01 and p = 0.001, respectively). Conclusions: High Immunoscore group had significantly superior OS and RFS and was an independent good prognostic factor for OS and RFS
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