Poor Joint Work in the Lower Limbs during a Tennis Forehand Groundstroke after a Cross-Over Step Inhibits an Increase in the Racket Speed.

A forward run-up and stepping are used to accelerate hitting tools or throwing objects in sports. This study aimed to investigate the effect of a forward cross-over step on the speed of a hitting tool by analyzing the joint work and mechanical energy of the whole body and the hitting tool using inverse dynamics. Thirteen advanced tennis players performed forehand groundstrokes at maximum effort with and without a forward cross-over step.

Mechanisms of speed-accuracy trade-off in tennis topspin forehand of college players.

This study aimed to elucidate the mechanisms underlying the speed-accuracy relationship in a tennis topspin single-handed forehand groundstroke. Groundstrokes at three different speeds by nine college players were captured, with the variability of the ball landing position evaluated as indices of accuracy. Variabilities of ball launch variables (speed, launch angle, spin, etc.

Congenital malformations caused by Akabane virus in porcine fetuses in southern Japan.

Akabane virus (AKAV) is known as a major teratogenic agent of ruminant fetuses. In this study, we investigated the relationship between porcine abnormal deliveries and AKAV by serology, pathology, and virology investigations using specimens from 16 stillborn fetuses delivered in southern Japan between 2013 and 2015. The major clinical manifestations in stillborn fetuses were hydranencephaly, arthrogryposis, spinal curvature, and both skeletal muscle and subcutaneous edema.

Directionally compensated mechanical work provided by the shoulder leads to similar racket velocities during open and square stance forehand groundstrokes in tennis.

The differences between the racket-arm acceleration mechanisms during open and square stance forehand groundstrokes in tennis were examined by quantifying the mechanical work done on the racket arm. We studied 13 advanced tennis players as they performed these strokes at maximum effort and calculated the work using inverse dynamics. The racket head speed was similar between the open and square stances.

A comparative study of LiCoO2 polymorphs: structural and electrochemical characterization of O2-, O3-, and O4-type phases.

O4-type LiCoO2 as a third polymorph of LiCoO2 is prepared by an ion-exchange method in aqueous media from OP4-[Li, Na]CoO2, which has an intergrowth structure of O3-LiCoO2 and P2-Na0.7CoO2. O4-type LiCoO2 is characterized by synchrotron X-ray diffraction, neutron diffraction, and X-ray absorption spectroscopy.

Generation of ultrashort optical pulses in the 10 fs regime using multicolor Raman sidebands in KTaO3.

We demonstrated Fourier synthesis of a new type of multiple coherent anti-Stokes Raman scatterings in KTaO(3) crystal. The signals with a wavelength range of 500-750 nm were generated by two femtosecond pulses whose frequency difference was set to be a two-phonon Raman frequency. Angle dispersion of the signals was compensated into one white-continuum beam by spherical mirrors and a prism.