Assessing the Vestibulo-ocular Reflex of Contralesional Sides According to Head Impulse Velocity Utilizing the Video Head Impulse Test in Patients with Vestibular Neuritis.

There is a lack of comparative studies examining changes in vestibulo-ocular reflex (VOR) gain with head velocity in the video head impulse test (vHIT) of patients with vestibular neuritis (VN). Thus, the purpose of present study was to identify the effect of head impulse velocity on the gain of the VOR during the vHIT in patients with VN. Head impulse velocities ranging from 100%-200°/s [158.08 ± 23.00°/s in the horizontal canal (HC), 124.88 ± 14.80°/s in the anterior canal (AC), and 122.92 ± 14.26°/s in the posterior canal (PC) were used during vHIT trials of 32 patients with VN. Differences in VOR gain on the ipsilesional and contralesional sides according to head velocity were analyzed. The mean VOR gains in ipsilesional side were decreased to 0.47 in the HC and 0.56 in the AC, leading to marked asymmetry compared to the contralesional side; PC gain was relatively preserved at 0.82 in the ipsilesional side. The mean head impulse velocity applied during vHIT trials in each semicircular canal plane did not differ bilaterally. On the contralesional side, VOR gain was negatively correlated with head impulse velocity (R2=0.25, P=.004 in HC; R2=0.17, P=.021 in AC; R2=0.24, P=.005 in PC), while VOR gain on the ipsilesional sides of the HC and AC was not. Head impulse velocity may have a differential impact on VOR gain, depending on the degree of deficit. Increasing head velocity in vHIT may be considered to identify subtle deficits on the contralesional side of patients with VN.

Enhanced photoactivity towards bismuth vanadate water splitting through tantalum doping: An experimental and density functional theory study.

The activation of hole trap states in bismuth vanadate (BiVO4) is considered an effective strategy to enhance the photoelectrochemical (PEC) water-splitting activity. Herein, we propose a theoretical and experimental study of tantalum (Ta) doping to BiVO4 leading to the introduction of hole trap states for the enhanced PEC activity. The doping of Ta is found to alter the structural and chemical surroundings via displacement of vanadium (V) atoms that cause distortions in the lattice via the formation of hole trap states. A significant enhancement of photocurrent to ∼4.2 mA cm-2 was recorded attributing to the effective charge separation of efficiency of ∼96.7 %. Furthermore, the doping of Ta in the BiVO4 lattice offers improved charge transport in bulk and decreased charge transfer resistance at the electrolyte interface. The Ta-doped BiVO4 displays the effective production of hydrogen (H2) and oxygen (O2) under AM 1.5 G illumination with a faradaic efficiency of 90 %. Moreover, the density functional theory (DFT) study confirms the decrease in optical band gap and the activation of hole trap states below the conduction band (CB) with a contribution of Ta towards both valence and CB that increases the charge separation and majority charge carrier density, respectively. The findings of this work propose that the displacement of V sites with Ta atoms in BiVO4 photoanodes is an efficient approach for enhanced PEC activity.