General Electric (Japan)

Abstract The abundance and distribution of rare-earth elements (REE) within fish debris from the Japanese Exclusive Economic Zone around Minami-Torishima Island have been investigated to determine the host materials of REE in the REE-rich deep-sea mud. The study was performed using REE-extraction experiments, field emission electron probe microanalysis (FE-EPMA), transmission electron microscopy with an energy-dispersive X-ray spectrometer (TEM-EDX), laser-induced breakdown spectroscopy (LIBS), Fourier-transform infrared (FTIR) spectroscopy and X-ray absorption near edge structure (XANES) analysis. The EPMA data indicate that the amount of REE in the apatite in the teeth is less than that in the bone debris. According to TEM-EDX analysis, yttrium (Y) is contained in the rod-like apatite crystals in the bone debris, but not in the long rod-like apatite crystals of the teeth. Analyses by LIBS and EPMA indicate that Y-rich bone debris is also rich in C. The FTIR spectroscopic analysis indicates the presence of carbonate groups within the Y-rich apatite structure. Moreover, the results of the XANES analysis and REE-extraction experiments indicate that Y occurs within the crystal structure of C-bearing apatite in the bone debris. These results suggest that the REE within C-bearing apatite in the fish debris from the Minami-Torishima REE-rich deep-sea mud substitute for Ca in apatite via an ionic exchange reaction, probably Ca 2 ⁺ + P⁵⁺ ↔ REE 3 ⁺ + C⁴⁺.

In this study, we present a method for evaluating liver viscoelasticity using continuous shear wave elastography with an arbitrary frequency selection. In the Voigt model, viscosity depends on the frequency of shear waves, thus allowing viscosity evaluation by combining measurements at different frequencies. The shear wave frequency must satisfy the continuous shear-wave elastography frequency conditions. Therefore, the shear-wave frequency was selected as an integer fraction of the pulse repetition frequency of the ultrasound device. Low-viscosity phantoms were used in this study. The frequency dependence of shear-wave velocity was confirmed using a viscous phantom. The shear wave velocity dispersion measured using the proposed method was 5.41–8.98 m/s/kHz for four healthy liver volunteers, which are similar to that of a healthy liver reported by magnetic resonance elastography (5.76–7.52 m/s/kHz). It has been demonstrated that the frequency dependence of shear wave propagation can be measured.

１．introductionDuring Japan's period of rapid economic growth, water pollution became a problem throughout the country, but water quality has improved rapidly thanks to the enactment of laws and the heightened environmental awareness of society as a whole. However, even now, not only is the concentration concentrated in Tokyo, but urbanization is also progressing in rural areas, and there are still areas with severe water pollution in the suburbs. What used to be point source pollution has spread to non-point source pollution. Due to problems with wastewater treatment facilities in mountainous areas, many large river basins are more polluted upstream than downstream. The results of the ``Survey of the Water Environment in Public Water Areas,'' which has been continued by the government since 1971, and the ``National Simultaneous Survey of Familiar Water Environments,'' which was started in 2004 by citizens' groups, are available on a nationwide scale. I have mainly studied long-term changes in river water quality in Japan. We will also consider the results of measurements by Hosei University in 2020 and 2021.２．Results and considerations１）Water quality survey results for public water areasThere were about 1,000 observation points in 1971, but 15 years later, in 1986, the number exceeded 5,000, and since then observations have continued at just under 6,000 points. In 1971, half of the BOD values were 3 or more, but in 1976 half were 2 or less, and recently, 2 or less accounted for about 80% (2018). The number of points with 1 to 4 remained unchanged, but 4 or more decreased, and 1 or less increased to about half of the total.２）Nationwide Simultaneous Survey of Familiar Water EnvironmentIn 2004, when the survey began, there were about 2,500 sites, but in 2005 there were about 5,000 sites, and after that, although it remained around 6,000 sites, it reached about 7,000 sites in 2018. COD4 or less is about half.３．conclusionIn addition to the nationwide long-term observation results, data from before 1971 were collected and organized in an attempt to reconstruct past water quality. With regard to recent water quality, we independently conduct observations at more than 1,500 points nationwide every year to clarify the current situation. In addition to the coastal area in 2020, we were able to investigate the inland area in 2021 and the municipality unit in 2022. We would like to improve the accuracy while continuing the wide-area survey.

CT systems with large detector size suffer from lower z-resolution leading to pixelated images and inability to detect small structures thus adversely impacting the diagnosis and screening. Overlap reconstruction can partially reduce the stair-step artifacts but does not improve the effect of wider slice sensitivity profile (SSP) and thus continues to have reduced visibility of smaller structures. In this work, we propose a supervised deep learning method for z-resolution enhancement such that (a) the effective SSP of resulting image is reduced, (b) quantitative values of tissue (CT numbers) and tissue-contrast are preserved; (c) very limited noise enhancement and (d) improved tissue interface in bone/soft tissue. The proposed method devises a super resolution (SURE) network which is trained to map the low resolution (LR) slices to the corresponding high resolution (HR) slices. A 2D network is trained with sagittal and coronal slices with the LR-HR pair sets. The training is performed using ground truth HR slices obtained from high end systems, and the corresponding LR slices are synthesized by either using retro reconstruction with higher slice thickness and spacing or through averaging of slices in z-direction from HR images. The network is trained with both these types of images with helical acquisition volumes from a range of scanners. Qualitative and quantitative analysis is done on the predicted HR images and compared with the original HR images. FWHM for SSP of the predicted HR images reduced from ~0.98 to ~0.73, when the target was 0.64, thus improving the real z-resolution. HU distribution of different tissue types also showed stability in terms of mean value. Noise measured through standard deviation was slightly higher than the LR image but lower than that of original HR images. PSNR also showed consistent improvement on all the cases across 3 different systems.

Spiral magnetic resonance imaging enables fast and efficient acquisition, although it suffers from aliasing artifact in cases of undersampling. It is still challenging to achieve fast and robust reconstruction for undersampled spiral datasets since iterative approaches are generally required. In this study, we developed a straightforward reconstruction method for spiral imaging using the non-uniform Fourier transform and convolutional neural networks (CNN). Two CNNs were used for estimating the sensitivity maps for parallel imaging and removing aliasing artifact caused by the undersampling. Simulation and volunteer studies were conducted to show the usefulness of our method. The results implied that the proposed method enables better performance than a conventional reconstruction method.

Abstract The ionospheric Alfvén resonator (IAR) is found in a dynamic power spectrum of the geomagnetic field variations as spectral resonance structures in the frequency range of 0.1–10 Hz. To date, observations of IAR at low latitude have only been made by a few studies employing a single ground observatory and are not sufficient enough to reveal its general characteristics. We analyze data measured with an induction magnetometer installed at Muroto, Japan (24.40° geomagnetic latitude) for the period from 28 December 2013 to 13 August 2016. A statistical analysis reveals that the occurrence probability of the low‐latitude IAR is (1) dominant during nighttime with a gradual increase from dusk to midnight and a broad maximum at 00–05 LT followed by a sudden decrease at dawn, (2) slightly higher during May through September, and (3) independent of the Kp index for Kp ≤ 5. We also find that (4) the frequency separation between the harmonics (Δf) of the low‐latitude IAR is 0.1–0.5 Hz with a peak at 0.2–0.275 Hz. These observational results are compared with the model calculation results along with previous studies about possible energy sources. It is found that the global thunderstorm activity is a likely source for IAR at Muroto; that is, it produces electromagnetic disturbances that are converted into the Alfvén waves and that are then trapped in the ionospheric cavity bounded by the conductive E layer and a steep gradient of Alfvén velocity above the F2 layer to form the resonant Alfvén waves.

We compared the regional cerebral blood flow (rCBF) obtained by pulsed continuous arterial spin labeling (pCASL) and iodine-123-N-isopropyl-p-iodoamphetamine (IMP) single photon emission computed tomography (SPECT) using 3-dimensional stereotactic region-of-interest (ROI) software for automated definition of ROIs in anatomic regions of the brain. Thirteen patients with cerebrovascular occlusive disease and three with transient ischemic attacks underwent pCASL and IMP SPECT imaging. We compared rCBF values of each anatomic region and calculated the correlation coefficients between pCASL and IMP SPECT. We also calculated the asymmetry index (AI) using ROIs in contralateral regions of the hemispheres. The rCBF values calculated from pCASL and IMP SPECT were comparable in most segments, but rCBF in the thalamus (P < 0.0001) and hippocampus (P = 0.0006) was significantly higher measured by pCASL than IMP SPECT. The correlation of rCBF between pCASL and IMP SPECT in the affected hemisphere (r = 0.50) tended to be lower than that in the normal hemisphere (r = 0.59), but not significantly different (P = 0.25). Moreover, there was a fixed bias for underestimation of rCBF by pCASL (P = 0.0047) in the affected hemisphere. The calculated AI showed a significant relationship between methods (r = 0.79, P < 0.0001). The rCBF obtained by pCASL had positive relationships with IMP SPECT. However, it should be considered that pCASL tends to have a weak relationship with IMP SPECT in some normal regions and regions affected by cerebrovascular occlusive disease.