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Liquid-phase synthesis is suitable for controlling the morphological and structural properties of functional inorganic materials and such control is important because they strongly affect the functionality of the product. Cobalt-based materials is one group of materials that requires control of powder morphology and structure. Cobalt is an important metal element used in various industrial fields such as secondary batteries, superalloys, permanent magnets, hard metals, and catalysts. The ever-growing demand of cobalt highlights that there is an urgent necessity to develop high quality material synthesis methods and to secure cobalt resources for countries that rely on import like Japan. Especially, technologies to recycle cobalt in a form reusable for secondary batteries and catalysts are desired because further increase in demand is anticipated. Meanwhile, spherical porous tricobalt tetroxide secondary particles obtained by calcination of spherical cobalt carbonate precursors have been reported to be promising materials for battery applications. Moreover, porous metal cobalt obtained by hydrogen reduction of tricobalt tetroxide is known to be effective for catalyst applications. However, conventional methods to synthesize spherical cobalt carbonate requires addition of additives in the reaction mixtures or otherwise requires hydrothermal treatment in pressure vessels. These are unfavorable to develop a practical and sustainable process for cobalt-based material production and recycling. In this study, a facile room temperature synthesis method to prepare spherical cobalt carbonate precursors from solutions of cobalt chloride and ammonium hydrogen carbonate that does not require any additives or hydrothermal treatment is developed by optimizing the carbonate solution concentration, carbonate/cobalt salt molar ratio, and stirring time during reaction. Furthermore, we succeeded in obtaining porous tricobalt tetroxide and porous metal cobalt that carry on the exterior spherical morphology of the original cobalt carbonate precursor by calcination and hydrogen reduction. The developed process shall contribute to realize high quality cobalt-based material production and recycling. [ABSTRACT FROM AUTHOR]

Consecutive sexual maturation (CSM), an abnormal reproductive phenomenon of a marine snail, Reishia clavigera, has occurred since 2017 in the vicinity of the Fukushima Daiichi Nuclear Power Plant after the nuclear disaster there. We hypothesized that alterations in animal physiology mediated through genetic/epigenetic changes could sensitively reflect environmental pollution. Understanding the mechanism of this rapid biological response should enable us to quantitatively evaluate long-lasting effects of the nuclear disaster. To determine the molecular basis for CSM, we conducted transcriptome profiling in the ganglia of normal and CSM snails. We assembled the short-read cDNA sequences obtained by Illumina sequencing, and succeeded in characterizing more than 60,000 gene models that include 88 kinds of neuropeptide precursors by BLAST search and experimental curation. GO-enrichment analysis of the differentially expressed genes demonstrated that severe downregulation of neuropeptide-related genes occurred concomitantly with CSM. In particular, significant decreases of the transcripts of 37 genes among 88 neuropeptide precursor genes, including those for myomodulin, PentaFVamide, maturation-associated peptide-5A and conopressin, were commonly observed in female and male CSM snails. By contrast, microseminoprotein precursor was the only exceptional case where the expression was increased in CSM snails. These results indicate that down-regulation of neuropeptide precursors is a remarkable feature of CSM. We also found that factors involved in epigenetic modification rather than transcription factors showed altered patterns of expression upon CSM. Comprehensive expression panels of snail neuropeptide precursors made in this study will be useful tools for environmental assessment as well as for studying marine reproductive biology. [ABSTRACT FROM AUTHOR]

Volcanic eruptions are sometimes preceded by tilt changes that are an indicator of immediate pre-eruptive processes. In this study, the tilt changes before all monitored eruptions in Japan were surveyed for the first time to address the generality and common features of these signals. An automated procedure was devised to identify tilt changes. The results showed that approximately half of the analyzed eruptions were preceded by tilt changes. Detection ratios depended on station locations, and approximately 10–20% of the total waveforms consisted of detectable tilt changes. Broadband seismic records, when integrated into displacements, showed detection ratios comparable to those of tiltmeter records. The lead times and durations of the tilt changes showed large variations. The durations correlated with amplitudes, although with considerable scatter. Both accelerating and decelerating types of tilt changes were common, and their ratios depended on the volcanoes. These are the first findings on the nature of pre-eruptive tilt changes from many volcanoes, and the waveform analysis procedure proposed in this paper is applicable to other regions. Future works involve extending this study to datasets from other regions, detecting tilt changes from continuous records, applying the proposed method to an early warning system, and detecting longer tilt changes, which require that the proposed approach be improved by subsequent studies. [Display omitted] • All pre-eruptive tilt changes in Japan were systematically surveyed. • Approximately half of the eruptions were preceded by tilt changes. • Broadband seismometers detected tilt changes at rates comparable to tiltmeters. • Durations of the tilt changes weakly correlated with amplitudes [ABSTRACT FROM AUTHOR]

Consecutive sexual maturation (CSM), an abnormal reproductive phenomenon of a marine snail, Reishia clavigera , has occurred since 2017 in the vicinity of the Fukushima Daiichi Nuclear Power Plant after the nuclear disaster there. We hypothesized that alterations in animal physiology mediated through genetic/epigenetic changes could sensitively reflect environmental pollution. Understanding the mechanism of this rapid biological response should enable us to quantitatively evaluate long-lasting effects of the nuclear disaster. To determine the molecular basis for CSM, we conducted transcriptome profiling in the ganglia of normal and CSM snails. We assembled the short-read cDNA sequences obtained by Illumina sequencing, and succeeded in characterizing more than 60,000 gene models that include 88 kinds of neuropeptide precursors by BLAST search and experimental curation. GO-enrichment analysis of the differentially expressed genes demonstrated that severe downregulation of neuropeptide-related genes occurred concomitantly with CSM. In particular, significant decreases of the transcripts of 37 genes among 88 neuropeptide precursor genes, including those for myomodulin, PentaFVamide, maturation-associated peptide-5A and conopressin, were commonly observed in female and male CSM snails. By contrast, microseminoprotein precursor was the only exceptional case where the expression was increased in CSM snails. These results indicate that down-regulation of neuropeptide precursors is a remarkable feature of CSM. We also found that factors involved in epigenetic modification rather than transcription factors showed altered patterns of expression upon CSM. Comprehensive expression panels of snail neuropeptide precursors made in this study will be useful tools for environmental assessment as well as for studying marine reproductive biology., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Morishita, Horiguchi, Akuta, Ueki and Imamura.)

As of mid-2014, the main organizations of the earthquake (EQ hereafter) prediction program, including the Seismological Society of Japan (SSJ), the MEXT Headquarters for EQ Research Promotion, hold the official position that they neither can nor want to make any short-term prediction. It is an extraordinary stance of responsible authorities when the nation, after the devastating 2011 M9 Tohoku EQ, most urgently needs whatever information that may exist on forthcoming EQs. Japan’s national project for EQ prediction started in 1965, but it has made no success. The main reason for no success is the failure to capture precursors. After the 1995 Kobe disaster, the project decided to give up short-term prediction and this stance has been further fortified by the 2011 M9 Tohoku Mega-quake. This paper tries to explain how this situation came about and suggest that it may in fact be a legitimate one which should have come a long time ago. Actually, substantial positive changes are taking place now. Some promising signs are arising even from cooperation of researchers with private sectors and there is a move to establish an “EQ Prediction Society of Japan”. From now on, maintaining the high scientific standards in EQ prediction will be of crucial importance. [ABSTRACT FROM AUTHOR]

Perfluoroalkyl acids (PFAAs) and their precursors have been used in various consumer products. However, limited information regarding their occurrence and concentration levels in products is available. In this study, we investigated 18 PFAAs and 14 PFAA precursors in various categories of consumer products purchased in Japan. Relatively high total concentrations of PFAAs and their precursors were found in sprays for fabrics and textiles (

Hydrological and geochemical studies for earthquake prediction in Japan during the last two decades are reviewed. Following the 1995 Hyogo-ken Nanbu (Kobe) earthquake, the central approach to research on earthquake prediction was modified. Instead of precursory detection, emphasis was placed on understanding the entire earthquake cycle. Moreover, the prediction program for the anticipated Tokai earthquake was revised in 2003 to include the detection of preslip-related precursors. These changes included the promotion of the following hydrological and geochemical studies for earthquake prediction: (1) development and/or application of statistical methods to extract small fluctuations from hydrological/geochemical data, (2) evaluation of the detectability of preslip-related anomalies in terms of groundwater levels in wells in the Tokai region, and (3) establishment of a new groundwater and borehole strain observation network for Nankai and Tonankai earthquake prediction research. The following basic geochemical studies were carried out: (1) development of a new monitoring system using a quadrupole mass spectrometer, (2) experimental studies on hydrogen generation by the grinding of rock and crystal powders, (3) comprehensive monitoring of groundwater gas and precise crustal deformation, and (4) mantle-derivative helium observation to compare with seismic velocity structures and the distribution of non-volcanic tremors. Moreover, hydrological and geochemical investigations related to the evolution of fault zones were introduced within the framework of fault zone drilling projects. [ABSTRACT FROM AUTHOR]

Monitoring of telluric current, which is practically a synonym for geoelectric potential difference, was conducted on Kozu-shima Island about 170 km south of Tokyo from May 14, 1997 to June 25, 2000. During the monitoring period, 19 anomalous telluric current changes (ATCs) were observed. Their possible correlation with nearby earthquakes was statistically examined by assuming various lead times for different ranges of magnitude and focal distance. The best correlation may be obtained for earthquakes with a magnitude greater than 3.0 occurring within 20 km of focal distance. There were 23 such earthquakes, of which 11 were preceded by ATCs within 30 d. Of these 11 earthquakes, preceding ATCs of 5 and 6 were positive and negative polarities of telluric current, respectively. Their epicenters were spatially well clustered in the east and west of the island. These facts were clearly beyond those expected by chance and led to a simple speculative model. [ABSTRACT FROM AUTHOR]

One of the important tools for seismic hazard risk assessment is study of the dynamics of properties of spatio-temporal distribution of the seismicity. We have performed simulation of the crack network development in elastic body under external stresses. We show that the crack network evolve from the state with random, chaotic distributions of cracks and seismicity to the state with fractal, clustered patterns. The validity of the results of simulations has been supported by the results of case studies of the seismicity catalogs for Japan and Southern California. It is shown that the variations of several multifractal characteristics (correlation dimension, information dimension, higher order generalized fractal dimensions, the abscissa of the top of multifractal spectrum) contain information about evolution of the system towards main rupture. We have found the certain tendencies in behavior of each multifractal characteristics which are in agreement with the results of simulation.Appreciable information on pre-rupture evolution of fault (crack) network in the lithosphere could be provided by study of the properties of coda waves scattered by the faults and inhomogeneities of the considered seismically active region. We have incorporated the results of simulation of the crack network evolution and solution of 2D problem of elastic waves propagation in elastic media containing a number of cracks. It is shown that the fractal dimension of synthetic seismograms of scattered waves decrease as the crack network evolve towards pre-rupture state. It is found that the spectrum of scattered waves evolved from the multiscaling to almost monoscaling form. That can be treated as manifestation of transition of the crack network from random to fractal, ordered state with pronounced scaling dependencies.The results obtained suggest the opportunity of using scaling characteristics of the seismicity and seismic coda waves for monitoring of the destruction process in seismically active areas and thus for a earthquake forecast. [Copyright &y& Elsevier]

We investigated the characteristics of the precursory seismicity changes associated with the M=6.8 Nemuro Peninsula earthquake, January 28, 2000 by applying the RTL (Region–Time–Length) algorithm to the earthquake catalogue of the Japan Meteorological Agency (JMA). The RTL parameters at the epicentre indicated that a seismic quiescence started in 1995 and reached its minimum during October 1996. An activation stage with a duration of about eight months followed. Our detailed investigations indicated that the RTL anomaly around 1996 was not an artificial effect due to the changes of the model parameters, the upgrade of the JMA seismic network or the process of aftershock elimination. The spatial distribution of quiescence in 1996 revealed a significant anomaly in a broad region around the epicentre of the Nemuro Peninsula earthquake. Following the quiescence stage, an activation zone, which was on the order of the rupture length of this earthquake, was obtained around the epicentre during October 1996–July 1997. The consistency of the rupture region and the anomalous activation zone that appeared after the seismic quiescence stage may provide useful information for determining the future risk zones. This study may strengthen the understanding of the seismogenic process of strong earthquakes. [Copyright &y& Elsevier]

• The contribution of DMF to NDMA FP was investigated in the aquatic environment • DMF was detected in influents of STPs with mass flux of 32.2–607 g/h • DMF was readily removed by biological treatment • STP effluent was an important source of DMF and NDMA FP in receiving rivers • DMF plays an important role in NDMA FP in surface waters The contribution of specific precursors to N -nitrosodimethylamine formation potential (NDMA FP) upon chloramination depends not only on their NDMA molar yields but also on their concentrations in the actual environment. We investigated the seasonal and diurnal patterns of the NDMA precursor N,N -dimethylformamide (DMF) and NDMA FP in the Yodo River basin, Japan, by examining water samples taken from inside the basin's largest sewage treatment plant (STP) as well as samples from five final effluents from four STPs, two main stream sites, and two tributary sites in the same basin. DMF and NDMA FP were found to be high in influent (raw sewage), and were found to be mostly removed during the STP treatment processes (especially with biological treatment). Nevertheless, DMF was found in concentrations of 0.06 to 31.7 µg/L in chlorinated effluents and in receiving rivers, while NDMA FP was detected in concentrations of 3.57 to 306 ng/L. Thus, STPs were shown to be an important source of DMF and NDMA FP to rivers. A strong positive correlation between NDMA FP and DMF was confirmed in the receiving river (K-M), indicating that DMF was an important NDMA precursor in the Yodo River basin. The contribution of DMF to NDMA FP was 15.8±11.2% (n = 4) in summer and 82.1±10.2% (n = 4) in winter in the main stream (site K-M) of the river due to insufficient dilution of chlorinated effluents from the largest STP. From the viewpoint of NDMA and NDMA FP control at downstream sites, monitoring and control of DMF at upstream sites are important. Image, graphical abstract [ABSTRACT FROM AUTHOR]