Autonomic nervous alterations associated with daily level of fatigue

<p>Abstract</p> <p>Background</p> <p>Fatigue is a common symptom in both sick and healthy people. We examined autonomic nervous alterations associated with fatigue to clarify the mechanisms underlying fatigue.</p> <p>Methods</p> <p>The study group consisted of 19 healthy participants who performed a 2-back test for 30 min as a fatigue-inducing mental task session. Before and after the session, they completed the advanced trail making test (ATMT) for 30 min for mental fatigue evaluation, subjective scales to measure fatigue sensation, and underwent electrocardiography to allow assessment of autonomic nerve activities.</p> <p>Results</p> <p>After the fatigue-inducing task, the total error counts on the ATMT tended to increase (<it>P </it>= 0.076); the ATMT for total trial counts (<it>P </it>= 0.001), the subjective level of fatigue (<it>P </it>< 0.001), and the % low-frequency power (%LF) (<it>P </it>= 0.035) increased significantly; and the % high-frequency power (%HF) decreased compared with before the fatigue-inducing task although this did not reach the statistical significance (<it>P </it>= 0.170). Although LF measured in absolute units did not change significantly before and after the fatigue-inducing task (<it>P </it>= 0.771), and HF measured in absolute units decreased after the task (<it>P </it>= 0.020). The %LF and LF/HF ratio were positively associated with the daily level of fatigue evaluated using Chalder's fatigue scale. In addition, %HF was negatively associated with the fatigue score.</p> <p>Conclusions</p> <p>Increased sympathetic activity and decreased parasympathetic activity may be characteristic features of both acute and daily levels of fatigue. Our findings provide new perspectives on the mechanisms underlying fatigue.</p

A transparent electrochromic metal-insulator switching device with three-terminal transistor geometry

Proton and hydroxyl ion play an essential role for tuning functionality of oxides because their electronic state can be controlled by modifying oxygen off-stoichiometry and/or protonation. Tungsten trioxide (WO3), a well-known electrochromic (EC) material for smart window, is a wide bandgap insulator, whereas it becomes a metallic conductor HxWO3 by protonation. Although one can utilize electrochromism together with metal-insulator (MI) switching for one device, such EC-MI switching cannot be utilized in current EC devices because of their two-terminal structure with parallel-plate configuration. Here we demonstrate a transparent EC-MI switchable device with three-terminal TFT-type structure using amorphous (a-) WO3 channel layer, which was fabricated on glass substrate at room temperature. We used water-infiltrated nano-porous glass, CAN (calcium aluminate with nanopores), as a liquid-leakage-free solid gate insulator. At virgin state, the device was fully transparent in the visible-light region. For positive gate voltage, the active channel became dark blue, and electrical resistivity of the a-WO3 layer drastically decreased with protonation. For negative gate voltage, deprotonation occurred and the active channel returned to transparent insulator. Good cycleability of the present transparent EC-MI switching device would have potential for the development of advanced smart windows

Purity and Defect Characterization of Single-Wall Carbon Nanotubes Using Raman Spectroscopy

We investigated the purity and defects of single-wall carbon nanotubes (SWCNTs) produced by various synthetic methods including chemical vapor deposition, arc discharge, and laser ablation. The SWCNT samples were characterized using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Raman spectroscopy. Quantitative analysis of SEM images suggested that the G-band Raman intensity serves as an index for the purity. By contrast, the intensity ratio of G-band to D-band (G/D ratio) reflects both the purity and the defect density of SWCNTs. The combination of G-band intensity and G/D ratio is useful for a quick, nondestructive evaluation of the purity and defect density of a SWCNT sample

Inter-Peer Group Status and School Bullying: The Case of Middle-School Students in Japan

The aim of the current study was to investigate the relationship between school bullying and inter-peer group status among Japanese middle-school students. A total of 2294, 7th–9th grade Japanese middle-school students participated in this study. Using a self-report questionnaire, we measured their inter- and intra-peer group status, bullying behavior, victimization, coping strategy, and current victimization status. The results showed that, compared to those in the higher-status groups, students in lower-status peer groups tended to be bullied and experienced prolonged victimization. These findings suggest that a lower peer-group status predisposes students to victimization

Inter-Peer Group Status and School Bullying: The Case of Middle-School Students in Japan

The aim of the current study was to investigate the relationship between school bullying and inter-peer group status among Japanese middle-school students. A total of 2294, 7th&ndash;9th grade Japanese middle-school students participated in this study. Using a self-report questionnaire, we measured their inter- and intra-peer group status, bullying behavior, victimization, coping strategy, and current victimization status. The results showed that, compared to those in the higher-status groups, students in lower-status peer groups tended to be bullied and experienced prolonged victimization. These findings suggest that a lower peer-group status predisposes students to victimization