Search

Functional magnetic resonance imaging (fMRI) conventionally relies on hemodynamics response induced some seconds after neural activation. Therefore, the temporal limitations of fMRI is the main challenge and we focused on the spin-lock sequence, which identifies neural magnetic field using magnetic resonance between the spin-lock pulse and the measurement target. This potentially addresses limitations of the traditional fMRI such as low temporal resolution and high static magnetic field. To enhance spin-lock sequences, it is essential to analyze magnetization dynamics during the spin-lock pulse. This study improved our previous proposal by presenting the particular solution of the Bloch equation, which allows us to consider the effect of $T_{1}$ relaxation. We also confirmed the novel solution with the comparison of numerical simulations without any approximation and discovered that the solution improved accuracy for $M_{y}$ and $M_{z}$ . The offset errors for $M_{y}$ and $M_{z}$ became smaller than $1\,\, {} \times {}10^{-5}$ times to the thermal equilibrium magnetization and the magnitude of errors was reduced to $3.2975\,\, {} \times {}10^{-3}$ and $1.3072\,\, {} \times {}10^{-1}$ times compared to our previous proposal. This improvement contributes to acquisition-integrated spin-lock sequences. There are still drawbacks due to the rotating wave approximation in our new proposal, but, it is applicable when the frequency bandwidth of spin-lock resonance is narrow, or the measurement target, such as a steady-state induced response, can be approximated by a single-frequency sine wave.

Recent observations beneath Kanto, Japan have shown that seismic activity and seismic attenuation within the overlying continental plate change with time due to drainage caused by slow‐slip events (SSEs) along the upper boundary of the Philippine Sea plate. However, associated changes in rock properties have not been investigated. In this study, we estimate frequency‐dependent shear‐wave anisotropy to provide a detailed insight into the structural change associated with drainage. We perform shear‐wave splitting analysis in frequency ranges of 1–4, 2–6, and 4–8 Hz for 306 earthquakes that occur during September 2009–August 2021 and recorded at the Metropolitan Seismic Observation network. Obtained time differences between fast and slow S waves (delay time) range from almost zero to 0.16–0.18 s, exhibiting spatio‐temporal variation and frequency dependence. The fast S‐wave polarization directions are generally consistent with the direction of the maximum horizontal compressional axis in the study region, which suggests that the observed anisotropy is probably caused by the NE–SW‐oriented fractures developed under the regional stress field. The temporal variation in delay times is correlated with SSEs activity with a lag time of 0.0–0.1 year. Furthermore, comparisons between observed frequency‐dependent delay times and numerical calculation of fracture‐induced anisotropy suggest that the average fracture radius is almost constant (0.30–0.35 m) over time but fracture density temporally varies from 0.025 to 0.035. We infer that the fracture density is probably enhanced by opening of the NE–SW‐oriented fractures during the upward migration of fluids that are expelled from the plate interface. Measurement of shear‐wave polarization anisotropy characterizes the intensity and orientation of fractures within the rocks beneath the Earth's surface. Furthermore, its frequency dependence provides important information for determining the fracture size and density. This study reveals that the strength of anisotropy shows temporal variations associated with the inferred periodic drainage from the subducting slab. We discuss a possible mechanism of the structural change focusing on the frequency dependence of the observed anisotropy and propose that the opening of fractures occurs immediately above the subducting slab following the periodic drainage. The obtained results will provide important constraints on fluid‐rock interaction above the subducting plate interface. Shear‐wave splitting analysis in Kanto, Japan suggests that seismic anisotropy is orientated sub‐parallel to the regional stressAnisotropy above the plate interface is enhanced with a lag of 0.0–0.1 years from the occurrence of slow‐slip eventsThe observed frequency‐dependent anisotropy suggests that fractures open responding to drainage from plate interface Shear‐wave splitting analysis in Kanto, Japan suggests that seismic anisotropy is orientated sub‐parallel to the regional stress Anisotropy above the plate interface is enhanced with a lag of 0.0–0.1 years from the occurrence of slow‐slip events The observed frequency‐dependent anisotropy suggests that fractures open responding to drainage from plate interface

Thin films made of carbon nanotubes are called buckypaper (BP), which is expected to be applied to electronic devices. Usually, BP is made by the chemical vapor deposition method. In this study, we used the vacuum filtration method to make low-cost BP. To justify the outstanding electronic performance of the fabricated BP, it was utilized to make the air-cathode of the aluminum-air battery. Since the BP is lighter and has a larger specific surface area than the carbon sheet, the aluminum-air battery can be miniaturized while increasing its performance. Furthermore, UV-ozone treatment was also applied to further improve the performance of the BP because it is able to clean and improve the surface conditions.

Water-activated paper-based batteries are expected to be low-cost disposable power sources for paper-based sensor applications. In this study, a disposable paper-based battery was developed. The battery used activated carbon powder loaded on a carbon sheet as the anode. The cathode was coated directly on a paper filter to fabricate an integrated proton exchange membrane cathode. Copper (II) chloride mixed with multiwalled carbon nanotube (CuCl2/CNT) was used as the cathode. Water was injected into the anode electrode to activate the battery. The maximum power density of 134.6μW/cm2was obtained with the anode loaded 17 mg cm−2activated carbon powder. The power output of the battery is proportional to the amount of activated carbon loaded on the anode.

AbstractNew application of fluorescence probe to detect apoplastic redox radicals from plant roots were sought. This probe can detect radicals selectively. Calibration curve for radicals was obtained using nitrogen monoxide as radical standard produced by NOC7. Apoplastic radicals released constitutively were quantified and the release rate was 60 μmol L−1 h−1. Oxidative burst triggered by chitin was distinguished from constitutive radical release.

Recent observations beneath central Japan have shown that periodic fluid drainage occurs during slow‐slip events (SSEs) based on temporal variations in QP−1${Q}_{P}^{-1}$above the megathrust boundary of the subducting Philippine Sea slab. However, no previous studies have estimated associated QS−1${Q}_{S}^{-1}$. A comparison of QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$can provide clues to the mechanism of seismic attenuation because of different propagation characteristics of the two waves. We estimate temporal variations in QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$via spectral analyses of waveform data from November 2009 to August 2021 period. The results indicate that both QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$exhibit temporal variations at about 1‐year periodicity and there are systematic differences between QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$that QS−1${Q}_{S}^{-1}$have smaller values, less insignificant variation, and weaker correlations with SSEs. Furthermore, QP−1/QS−1${Q}_{P}^{-1}/{Q}_{S}^{-1}$increases concurrent with SSEs. These differences suggest that attenuation is caused by the wave‐induced fluid flow. QP−1/QS−1${Q}_{P}^{-1}/{Q}_{S}^{-1}$could be an important parameter for detecting the presence of fluid. Q−1${Q}^{-1}$value, which represents energy dissipation of seismic wave, is an important parameter for detecting the anelastic heterogeneity in subsurface rocks. However, few observational studies have revealed the characteristics of both P‐ and S‐wave attenuation (QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$, respectively) related to the presence of fluids in the crust and the uppermost mantle. This study reveals that both QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$show temporal variations associated with the inferred periodic drainage from the upper surface of a subducting slab but QS−1${Q}_{S}^{-1}$is less fluctuated with time. We discuss a possible attenuation mechanism focusing on the differences in the observed QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$values and propose that the wave‐induced fluid flow (WIFF) may be a dominant control on the increases in attenuation concurrent with the drainage from the megathrust. The obtained results will provide important constraints on attenuation mechanism that is enhanced by the presence of fluid in rocks. We estimated the long‐term temporal variations in QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$at 20–45 Hz above the megathrust boundary of the Philippine Sea PlateBoth QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$exhibited temporal variations with about 1‐year periodicity and spatiotemporal correlations with slow‐slip eventsSystematic differences between QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$may provide important constraints on attenuation mechanism enhanced by fluids We estimated the long‐term temporal variations in QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$at 20–45 Hz above the megathrust boundary of the Philippine Sea Plate Both QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$exhibited temporal variations with about 1‐year periodicity and spatiotemporal correlations with slow‐slip events Systematic differences between QP−1${Q}_{P}^{-1}$and QS−1${Q}_{S}^{-1}$may provide important constraints on attenuation mechanism enhanced by fluids

Carbon-fiber-reinforced plastic (CFRP) is used in various industries such as aerospace and automobile industries because of its high mechanical characteristics. However, this material is difficult to cut. Tool wear and delamination frequently occur during the drilling or cutting of CFRP. In previous studies, we developed a CFRP cutting tool using polycrystalline diamond (PCD). The PCD tool exhibited excellent cutting performance at cutting speeds as low as <120 m/min. In this study, the authors investigated the effect of cutting speed on the face milling of CFRP by using the developed PCD tool.

Acute kidney injury (AKI) after cardiac surgery increases the risk of morbidity and mortality. Hydroxyethyl starch (HES) is often used during surgery due to its plasma-volume expanding effect, but the impact of HES 130/0.4 on renal function in patients undergoing cardiac surgery remains unclear. The aim of our study is to investigate the impact of HES 130/0.4 on postoperative renal function in patients undergoing cardiac surgery using cardiopulmonary bypass.

We have investigated the discharge mechanisms in a helium plasma jet with a coaxial dielectric barrier discharge (DBD) configuration, which can generate low-temperature plasma plume mainly by positive corona streamer propagation. In this study, we focused on the relationships between the coaxial DBD inside a glass tube and the positive streamer propagating in the plasma plume, using novel types of electrode configurations composed of insulated electric wires. The discharge characteristics were investigated by measuring plume length, discharge currents of the DBD, and the line-integrated density of helium metastable atoms in the plume. The experimental results indicate that the excited-species density in the plume is largely dependent on surface-charge density accumulated by the DBD. Moreover, we analyzed the spatiotemporal distribution of electrical potential around the tube exit by the finite element method, and discussed the mechanism determining plume length.

Abstract: A low-cost and simple monitoring method for early warning of landslides is proposed. To detect abnormal deformation of a slope, this method employs a tilt sensor in place of an extensometer on the slope surface. In order to examine the relevance of measuring rotation angle on a slope surface by tilt sensor, model tests were conducted, and rotation on the slope surface was observed together with slide displacement along the surface. The rotation data responded 30 min before failure in a model test, which could be useful as a signal for early warning. However, the behavior of rotation before failure varies from case to case, and thus, criteria to issue warning should be defined more carefully. For a model slope made of uniform loose sand, measurement of slide displacement along the slope surface is sensitive to failure at the toe, while the measurement of rotation on the slope surface is useful to detect the development of progressive failure upward along the slope. Wireless sensor units with microelectromechanical systems (MEMS) tilt sensor and volumetric water content sensor were also examined on a real slope in Kobe City, and a long-term monitoring was attempted. A simple but possible way to define the criteria of judgment to issue warning can be proposed based on combination of data obtained by the tilt sensors and volumetric water content sensors.

In order to investigate the effect of accumulated charge on a substrate surface in the deposition of a SiO2film with an atmospheric-pressure plasma jet, we have measured the discharge current flowing into a copper substrate, which was placed 20 mm from the exit of the plasma jet and connected to a variable capacitor in series. We found that the discharge current decreased markedly when the capacitance of the substrate was below 100 pF, and the deposition rate of SiO2traced the variation of the capacitance. To analyze the behavior of the plasma jet, we considered an equivalent circuit of our system and verified the validity of our supposition that the accumulated charge restricts the deposition rate. Thereby, we found that the discharge current and deposition rate were determined by the capacitance of both the glass tube wall and the substrate.

Although recent reports suggest that the endoplasmic reticulum (ER) stress response is induced in association with the development of inflammatory bowel disease, its role in the pathogenesis of inflammatory bowel disease remains unclear. The CCAAT/enhancer-binding protein (C/EBP) homologous protein (CHOP) is a transcription factor that is involved in the ER stress response, especially ER stress-induced apoptosis. In this study, we found that experimental colitis was ameliorated in CHOP-null mice, suggesting that CHOP exacerbates the development of colitis. The mRNA expression of Mac-1(CD11b, a positive regulator of macrophage infiltration), Ero-1α, and Caspase-11(a positive regulator of interleukin-1β production) in the intestine was induced with the development of colitis, and this induction was suppressed in CHOP-null mice. ERO-1α is involved in the production of reactive oxygen species (ROS); an increase in ROS production, which is associated with the development of colitis in the intestine, was suppressed in CHOP-null mice. A greater number of apoptotic cells in the intestinal mucosa of wild-type mice were observed to accompany the development of colitis compared with CHOP-null mice, suggesting that up-regulation of CHOP expression exacerbates the development of colitis. Furthermore, this CHOP activity appears to involve various stimulatory mechanisms, such as macrophage infiltration via the induction of Mac-1, ROS production via the induction of ERO-1α, interleukin-1β production via the induction of Caspase-11, and intestinal mucosal cell apoptosis.

We report here a simple and straightforward method that enables the size-controlled production of zeolitic imidazolate framework-8 in an aqueous system at room temperature. Pure single crystals with the size tuned in the range of ca. 300 nm to 3 µm in mean crystal size can be obtained and exhibit ultrahigh Langmuir surface area of above 1800 m2g−1.

The Mn(III)‐based oxidative macrocyclization followed by dihydrofuranation is demonstrated to be an effective method for the synthesis of macrolides of even more than 20 members without polymerization.

The behavior of N2+ ions in a low-frequency driven atmospheric pressure He plasma jet effused into ambient air was analyzed from laser induced fluorescence (LIF) spectroscopy measurements. The gas temperature derived from the rotational distribution was kept near room temperature and the drift velocity of N2+ ions estimated from the line shape was almost zero as compared to the apparent speed of the plasma bunch given by the spatiotemporal intensity profile. This shows that the mechanism of moving plasma bunches can be attributed to the ionization wave propagation similar to the streamer in positive corona discharge.

We present an experimental study of plasma enhanced chemical vapor deposition (PECVD) of SiO2 films from tetraethoxysilane (TEOS) using a plasma jet based on capillary dielectric barrier discharge (CDBD) at atmospheric pressure. We tried three different configurations: (a) coaxial type, (b) a crossed type with a vertical plasma jet and a tilted TEOS supply, and (c) another crossed type with the reversed arrangement. The deposition rate of SiO2 films increased with the driving frequency of the plasma jet in all configurations, and as the best record it reached up to 280 nm/s at a frequency of 15 kHz in the configuration (c) with the aid of O3 supply, which was three times as fast as that measured in the configuration (a) without O3 supply.

The behavior of N2+ions in a low-frequency driven atmospheric pressure He plasma jet effused into ambient air was analyzed from laser induced fluorescence (LIF) spectroscopy measurements. The gas temperature derived from the rotational distribution was kept near room temperature and the drift velocity of N2+ions estimated from the line shape was almost zero as compared to the apparent speed of the plasma bunch given by the spatiotemporal intensity profile. This shows that the mechanism of moving plasma bunches can be attributed to the ionization wave propagation similar to the streamer in positive corona discharge.

We present an experimental study of plasma enhanced chemical vapor deposition (PECVD) of SiO2films from tetraethoxysilane (TEOS) using a plasma jet based on capillary dielectric barrier discharge (CDBD) at atmospheric pressure. We tried three different configurations: (a) coaxial type, (b) a crossed type with a vertical plasma jet and a tilted TEOS supply, and (c) another crossed type with the reversed arrangement. The deposition rate of SiO2films increased with the driving frequency of the plasma jet in all configurations, and as the best record it reached up to 280 nm/s at a frequency of 15 kHz in the configuration (c) with the aid of O3supply, which was three times as fast as that measured in the configuration (a) without O3supply.