Yoshitaka Okada

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INTRODUCTION The origin of the vertebral artery (VA) varies, though most VAs enter the transverse foramen (TF) of the sixth cervical vertebra. On computed tomography (CT) angiographic images, we evaluated the prevalence of variations of both VA origin and its level of entry into the TF. METHODS We retrospectively reviewed CT angiographic images of 2,287(More)
We report for the first time a successful fabrication and operation of an InAs/GaAs quantum dot based intermediate band solar cell concentrator photovoltaic (QD-IBSC-CPV) module to the IEC62108 standard with recorded power conversion efficiency of 15.3%. Combining the measured experimental results at Underwriters Laboratory (UL®) licensed testing laboratory(More)
INTRODUCTION The craniovertebral junction is clinically important. The vertebral artery (VA) in its several variations runs within this area. We report the prevalence of these VA variations on magnetic resonance angiography (MRA). METHODS We retrospectively reviewed MRA images, obtained using two 1.5-T imagers, of 2,739 patients, and paid special(More)
INTRODUCTION Persistent hypoglossal artery (PHA) is the second most common anastomosis between the carotid and vertebrobasilar systems and demonstrates some variations. We evaluated the prevalence of PHA on computed tomography (CT) angiography. We also evaluated characteristic features of PHA and its variants on magnetic resonance (MR) angiography. (More)
INTRODUCTION Fenestrations of cerebral arteries are most common in the vertebrobasilar (VB) system, and magnetic resonance (MR) angiographic studies of these variations are sparse. METHODS We retrospectively reviewed MR angiographic images of 3,327 patients; images were obtained using two 1.5-T imagers and picked up fenestrations of the intracranial(More)
The doping characteristics and carrier transport in a GaAs p-n junction were visualized with a approximately 10 nm spatial resolution, using light-modulated scanning tunneling spectroscopy. The dynamics of minority carriers under operating conditions, such as recombination, diffusion, and electric field induced drift, which had previously been analyzed on(More)
INTRODUCTION It is well known that the occipital artery (OA) can arise from the internal carotid artery (ICA) or vertebral artery (VA). However, the incidence of an anomalously originating OA has not been reported. We investigate its incidence and characteristic features on magnetic resonance angiography (MRA). METHODS We retrospectively reviewed MRA(More)
Advanced concepts for high efficiency solar cells such as hot carrier effects, Multi-Exciton Generation (MEG), and Intermediate-Band (IB) absorption in low-dimensional nanostructures are under focused research topics in recent years. Among various potential approaches, this chapter is devoted to the device physics and development of the state-of-the-art(More)
The direct conversion of solar energy to electricity can be broadly separated into two main categories: photovoltaics and thermal photovoltaics, where the former utilizes gradients in electrical potential and the latter thermal gradients. Conventional thermal photovoltaics has a high theoretical efficiency limit (84%) but in practice cannot be easily(More)