Boundary Scattering in Ballistic Graphene

We report magnetotransport measurements in ballistic graphene/hexagonal boron nitride mesoscopic wires where the charge carrier mean free path is comparable to wire width $W$. Magnetoresistance curves show characteristic peak structures where the peak field scales with the ratio of cyclotron radius $R_\textrm{c}$ and wire width $W$ as $W/R_\textrm{c} = 0.9 \pm 0.1$, due to diffusive boundary scattering. The obtained proportionality constant between $R_\textrm{c}$ and $W$ differs from that of a classical semiconductor 2D electron system where $W/R_\textrm{c} = 0.55$.Comment: 14 pages, 4 figure

グラフェンナノ構造の作製と光検出素子への応用

学位の種別:課程博士University of Tokyo(東京大学

Balance Measures Derived from Insole Sensor Differentiate Prodromal Dementia with Lewy Bodies

Dementia with Lewy bodies is the second most common type of neurodegenerative dementia, and identification at the prodromal stage$-$i.e., mild cognitive impairment due to Lewy bodies (MCI-LB)$-$is important for providing appropriate care. However, MCI-LB is often underrecognized because of its diversity in clinical manifestations and similarities with other conditions such as mild cognitive impairment due to Alzheimer's disease (MCI-AD). In this study, we propose a machine learning-based automatic pipeline that helps identify MCI-LB by exploiting balance measures acquired with an insole sensor during a 30-s standing task. An experiment with 98 participants (14 MCI-LB, 38 MCI-AD, 46 cognitively normal) showed that the resultant models could discriminate MCI-LB from the other groups with up to 78.0% accuracy (AUC: 0.681), which was 6.8% better than the accuracy of a reference model based on demographic and clinical neuropsychological measures. Our findings may open up a new approach for timely identification of MCI-LB, enabling better care for patients

Characterization of silk gland ribosomes from a bivoltine caddisfly, Stenopsyche marmorata: translational suppression of a silk protein in cold conditions

Larval Stenopsyche marmorata constructs food capture nets and fixed retreats underwater using self-produced proteinaceous silk fibers. In the Chikuma River (Nagano Prefecture, Japan) S. marmorata has a bivoltine life cycle; overwintering larvae grow slowly with reduced net spinning activity in winter. We recently reported constant transcript abundance of S. marmorata silk protein 1 (Smsp-1), a core S. marmorata silk fiber component, in all seasons, implying translational suppression in the silk gland during winter. Herein, we prepared and characterized silk gland ribosomes from seasonally collected S. marmorata larvae. Ribosomes from silk glands immediately frozen in liquid nitrogen (LN2) after dissection exhibited comparable translation elongation activity in spring, summer, and autumn. Conversely, silk glands obtained in winter did not contain active ribosomes and Smsp-1. Ribosomes from silk glands immersed in ice-cold physiological saline solution for approximately 4 h were translationally inactive, despite summer collection and Smsp-1 expression. The ribosomal inactivation occurs because of defects in the formation of 80S ribosomes, presumably due to splitting of 60S subunits containing 28S rRNA with central hidden break, in response to cold stress. These results suggest a novel-type ribosome-regulated translation control mechanism.ArticleBiochemical and Biophysical Research Communications.469(2):210-215(2016)journal articl