138 research outputs found

    CHARACTERISTICS OF A WELL-DONE BREAKING PITCH IN BASEBALL

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    This study aimed to quantify well-done breaking pitches as evaluated by experienced catchers in baseball. Twenty college baseball pitchers threw one pitch for each type of pitch that they typically played in a game. Pitched ball velocity, spin rate, spin component, and displacement were calculated. Nine catchers of the same team evaluated each breaking pitch (curveball, slider, and changeup) of all the pitchers, and the relationships between the catchers’ evaluation and the quantitative variables were then investigated. Thus, with respect to the curveball, significant correlations were observed between the catchers’ evaluation and total spin rate, back spin, and vertical displacement. With respect to the slider, significant correlation was observed between the catchers’ evaluation and ratio of the velocity of the slider relative to the fastball. With respect to the changeup, significant correlation was not observed for any of the variables. The results are expected to act as a good benchmark for pitchers to improve their breaking pitches

    SPIN OF A BATTED BALL TOWARD THE OPPOSITE FIELD IN BASEBALL

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    The purpose of this study was to investigate the spinning motion of a ball batted toward the opposite field in baseball. A pitching machine was used to launch the balls toward the bat, which was adjusted and tied up to hit the balls in the opposite field. The ball movements were recorded using three high-speed video cameras. The results indicated that the batted ball backspin and sidespin components correlate strongly with the launch elevation angles and launch horizontal angles, respectively. All the batted balls had a certain amount of sidespin components. The balls batted toward the opposite field experienced unavoidable horizontal Magnus force, resulting in curving. Thus, it is important to launch the balls with a larger velocity to hit a long ball toward the opposite field while comparing with the balls batted towards the same field with less sidespin components

    THREE-DIMENSIONAL KINEMATICS OF THE BATTED BALL IN BASEBALL: THE EFFECT OF SPIN ON THE BALL TRAJECTORY AND FLIGHT DISTANCE

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    The purpose of this study was to describe the three-dimensional kinematics of batted baseballs toward the same-field, center-field, and opposite-field, and estimate the effect of ball spin on trajectory and flight distance. Two collegiate baseball players performed free-batting, and they were instructed to hit a ball as far as possible in each direction. Twenty-seven trials were analyzed, and compared the ball kinematics among three hitting directions. The mean flight distance for the center-field was greater than that of the other fields. For the same-field and opposite-field, the amount of side spin components was larger than that of the center-field. Thus, it was indicated that the batted ball trajectories for the same-field and opposite-field were curved due to the Magnus force works horizontally, and flight distance tended to be shorter than that of the center-field

    KINEMATICS OF MEN STRIKING MOTION IN EIGHTH DAN KENDO PLAYERS

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    The purpose of this study was to explore the time series kinematic variations during the men striking motion in eighth dan kendo players. Moreover, the magnitude of the individual difference and timing at which it appeared were investigated. Ten eighth dan kendo players performed men striking towards one of two targets (men or kote) with maximum effort immediately after an LED lamp was lighted. The motions were recorded using a motion capture system. This study examined the time series kinematic variations during the men striking motion, and revealed that the movements of the shinai (sword), right and left shoulders, and right hip differed substantially among individuals from each standard deviation

    BIOMECHANICAL STUDY ON DIFFERENT DIRECTIONS FOR RUNNING JUMPS FOCUSED ON THE TAKEOFF PREPARATION

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    This study aimed to elucidate the difference in CG parameters from three steps, prejump to takeoff step of the jump motion (running jump), and obtain primary data on takeoff preparation action. Five male jumpers associated with the university track and field department were trained to perform their best at (1) approach run with no takeoff (RUN), (2) jumping as far as possible (long jump [LJ]), and (3) jumping as high as possible (high jump [HJ]), which were recorded using a three-dimensional capture system. As a result, significant differences were observed in not only the takeoff but also the takeoff preparation phase regarding CG parameters, suggesting the need to focus on the takeoff preparation phase as a factor that determines jump direction. Moreover, HJ and LJ suppressed an increase in vertical velocity one step prior, and by takeoff at a lower CG, the athletes allowed for an easier increase in takeoff angle and jump height. However, to resist a decrease in horizontal velocity, LJ transitioned to takeoff in a manner closer to RUN and without changing takeoff preparation as much as that in HJ. Thus, adjusting vertical velocity and height one step before takeoff can influence takeoff angle

    Improving the tensile properties of additively manufactured β-containing tial alloys via microstructure control focusing on cellular precipitation reaction

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    The effect of a two-step heat treatment on the microstructure and high-temperature tensile properties of β-containing Ti-44Al-4Cr (at%) alloys fabricated by electron beam powder bed fusion were examined by focusing on the morphology of α2/γ lamellar grains and β/γ cells precipitated at the lamellar grain boundaries by a cellular precipitation reaction. The alloys subjected to the first heat treatment step at 1573 K in the α + β two-phase region exhibit a non-equilibrium microstructure consisting of the α2/γ lamellar grains with a fine lamellar spacing and a β/γ duplex structure located at the grain boundaries. In the second step of heat treatment, i.e., aging at 1273 K in the β + γ two-phase region, the β/γ cells are discontinuously precipitated from the lamellar grain boundaries due to excess Cr supersaturation in the lamellae. The volume fraction of the cells and lamellar spacing increase with increasing aging time and affect the tensile properties of the alloys. The aged alloys exhibit higher strength and comparable elongation at 1023 K when compared to the as-built alloys. The strength of these alloys is strongly dependent on the volume fraction and lamellar spacing of the α2/γ lamellae. In addition, the morphology of the β/γ cells is also an important factor controlling the fracture mode and ductility of these alloys.Cho K., Odo H., Okamoto K., et al. Improving the tensile properties of additively manufactured β-containing tial alloys via microstructure control focusing on cellular precipitation reaction. Crystals, 11, 7, 809. https://doi.org/10.3390/cryst11070809

    Disconnectivity between Dorsal Raphe Nucleus and Posterior Cingulate Cortex in Later Life Depression

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    The dorsal raphe nucleus (DRN) has been repeatedly implicated as having a significant relationship with depression, along with its serotoninergic innervation. However, functional connectivity of the DRN in depression is not well understood. The current study aimed to isolate functional connectivity of the DRN distinct in later life depression (LLD) compared to a healthy age-matched population. Resting state functional magnetic resonance imaging (rsfMRI) data from 95 participants (33 LLD and 62 healthy) were collected to examine functional connectivity from the DRN to the whole brain in voxel-wise fashion. The posterior cingulate cortex (PCC) bilaterally showed significantly smaller connectivity in the LLD group than the control group. The DRN to PCC connectivity did not show any association with the depressive status. The findings implicate that the LLD involves disruption of serotoninergic input to the PCC, which has been suggested to be a part of the reduced default mode network in depression

    Effects of Tissue Pressure on Transgene Expression Characteristics via Renal Local Administration Routes from Ureter or Renal Artery in the Rat Kidney

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    We previously developed a renal pressure-mediated transfection method (renal pressure method) as a kidney-specific in vivo gene delivery system. However, additional information on selecting other injection routes and applicable animals remains unclear. In this study, we selected renal arterial and ureteral injections as local administration routes and evaluated the characteristics of gene delivery such as efficacy, safety, and distribution in pressured kidney of rat. Immediately after the naked pDNA injection, via renal artery or ureter, the left kidney of the rat was pressured using a pressure controlling device. Transfection efficiency of the pressured kidney was about 100-fold higher than that of the injection only group in both administration routes. The optimal pressure intensity in the rat kidney was 1.2 N/cm2 for renal arterial injection and 0.9 N/cm2 for ureteral injection. We found that transgene expression site differs according to administration route: cortical fibroblasts and renal tubule in renal arterial injection and cortical and medullary tubule and medullary collecting duct in ureteral injection. This is the first report to demonstrate that the renal pressure method can also be effective, after renal arterial and ureteral injections, in rat kidney

    Two Cases of High Tibial Osteotomy in Patients with Rheumatoid Arthritis Treated with Biologic Disease-modifying Anti-rheumatic Drugs

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    High tibial osteotomy (HTO) procedure is generally contraindicated in rheumatoid arthritis (RA) patients because synovial inflammation may exacerbate joint damage post-surgery. The natural course of joint destruction in RA changed dramatically with new treatment strategies and the introduction of biologic disease-modifying anti-rheumatic drugs (bDMARDs). We report the cases of two RA patients who underwent HTO and whose disease activities were well controlled by bDMARDs. Despite their short follow-up periods, they showed acceptable objective and subjective clinical results. We believe that the combination of bDMARDs and HTO can be indicated for selected RA patients before total knee arthroplasty

    Effects of empagliflozin in patients with chronic kidney disease from Japan: exploratory analyses from EMPA–KIDNEY

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    Background: EMPA–KIDNEY assessed the effects of empagliflozin 10 mg once daily vs. placebo in 6609 patients with chronic kidney disease (CKD) at risk of progression, including 612 participants from Japan. Methods: Eligibility required an estimated glomerular filtration rate (eGFR) of ≥ 20  Results: Japanese participants had higher levels of albuminuria and eGFR than those from non-Japan regions. During a median of 2.0 year follow-up, a primary outcome occurred in 432 patients (13.1%) in the empagliflozin group and in 558 patients (16.9%) in the placebo group (hazard ratio [HR], 0.72, 95% confidence interval [95%CI] 0.64–0.82; P  Conclusions: Empagliflozin safely reduced the risk of “kidney disease progression or cardiovascular death” in patients with CKD, with consistent effects in participants from Japan
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