The stress field is a key factor controlling earthquake occurrence and crustal evolution. In this study, we propose an approach for determining the stress field in a region using seismic moment ...tensors, based on the classical equation in plasticity theory. Seismic activity is a phenomenon that relaxes crustal stress and creates plastic strain in a medium because of faulting, which suggests that the medium could behave as a plastic body. Using the constitutive relation in plastic theory, the increment of the plastic strain tensor is proportional to the deviatoric stress tensor. Simple mathematical manipulation enables the development of an inversion method for estimating the stress field in a region. The method is tested on shallow earthquakes occurring on Kyushu Island, Japan.
Key Points
Estimation of stress field using sum of seismic moment tensors based on classical equation in plasticity theory
Simple summation of seismic moment tensors provides stress tensor without instability due to nonlinearity in the ordinary stress inversion
The results of the estimated stress tensor in this study mostly coincide with those obtained by ordinal stress tensor inversion
Volcano monitoring systems are not always ready to resolve signals at the onset of eruptive activity. This study makes use of stations installed later to calibrate the performance of the stations ...that had been operated before the eruption. Seven stations recorded continuous volcanic tremor before and during the subplinian eruptions of Shinmoe‐dake, Japan, in 2011. We estimated the source locations of the tremor using the amplitude distribution. The stability of the analysis was obtained by careful selection of time windows in which signals from a single source are dominated. The site effects and the regional attenuation factor were evaluated using tremor recorded after the major eruptions by a dense seismic array and a good number of stations. A tremor source changed its depth beneath the crater for 1 week before the major eruption, rising from a depth of a few kilometer to the water layer 3 times, each of which occurred following shallow inflation and minor eruptions. It is interpreted as migration of gas probably with magma, which further transported heat to the water layer and triggered the subplinian eruptions.
Plain Language Summary
Shinmoe‐dake, Japan had a relatively large eruption in 2011 for the first time in 300 years. Although continuous seismic signal, which is called tremor, indicating magma or gas movement had been recorded before the main eruptive event, we did not have sufficient seismic stations to capture the magma movement. After the main eruption, more seismic stations were installed and recorded tremor that continued with less energetic eruptions. In this study, we make use of the data after the main eruption to calibrate the performance of the stations that had been operated before the eruption. We successfully revealed the movement of the tremor source before the eruption in correlation with shallow inflation and precursory eruptions. The result was interpreted as movement of magma and gas that supplied heat to the water layer in the ground and triggered the eruption. It is demonstrated that seismic stations even deployed after an eruption are useful in assessing processes preceding the eruption.
Key Points
A dense seismic array is used for calibration of seismic stations to improve accuracy of amplitude‐based source location
Upward source migration with shallow inflation and/or minor precursory eruption was clearly detected as an indication of fluid movement
Installing seismic stations including an array is important even after an eruption starts to understand processes before the eruption
Wnt5a is a representative ligand that activates the β‐catenin‐independent pathways. Because the β‐catenin‐independent pathway includes multiple signalling cascades in addition to the planar cell ...polarity and Ca2+ pathway, Wnt5a regulates a variety of cellular functions, such as proliferation, differentiation, migration, adhesion and polarity. Consistent with the multiple functions of Wnt5a signalling, Wnt5a knockout mice show various phenotypes, including an inability to extend the embryonic anterior–posterior and proximal–distal axes in outgrowth tissues. Thus, many important roles of Wnt5a in developmental processes have been demonstrated. Moreover, recent reports suggest that the postnatal abnormalities in the Wnt5a signalling are involved in various diseases, such as cancer, inflammatory diseases and metabolic disorders. Therefore, Wnt5a and its signalling pathways could be important targets for the diagnosis and therapy for human diseases.
We recently demonstrated that expression of ADP-ribosylation factor (ARF)-like 4c (Arl4c) induced by a combination of Wnt/β-catenin and epidermal growth factor/Ras signaling in normal epithelial ...cells grown in three-dimensional culture promotes cellular migration and proliferation, resulting in formation of tube-like structures, suggesting the involvement of Arl4c in epithelial morphogenesis. It is conceivable that there could be a common mechanism between epithelial morphogenesis and carcinogenesis. Therefore the current study was conducted to investigate whether Arl4c might be involved in tumorigenesis. Immunohistochemical analyses of tissue specimens obtained from colorectal and lung cancer patients revealed that Arl4c was not observed in non-tumor regions but was strongly expressed at high frequencies in tumor lesions. Inhibition of Wnt/β-catenin or Ras/mitogen-activated protein kinase signaling reduced Arl4c mRNA levels in HCT116 colorectal cancer cells and A549 lung cancer cells. Knockdown of Arl4c inhibited Rac activity and also prevented nuclear localization of yes-associated protein (YAP)/transcriptional co-activator with PDZ-binding motif (TAZ) in these cancer cells. Arl4c-depleted cancer cells consistently showed decreased migration, invasion and proliferation capabilities both in vitro and in vivo. Furthermore, direct injection of Arl4c small interfering RNA (siRNA) into HCT116 cell-derived tumors (in vivo treatment with siRNA) inhibited tumor growth in immunodeficient mice. These results suggest that Arl4c is involved in tumorigenesis and might represent a novel therapeutic target for suppressing proliferation and invasion of colorectal and lung cancer cells.
Exposure to workplace aggression adversely affects workers' health; however, little is known regarding the impact of specific types of verbal content.
We aimed to examine the relationship between ...exposure to several types of aggressive words at work and the victim's depressive symptoms and sleep disturbance using text mining.
We conducted a longitudinal survey with 800 workers in wholesale and retail companies; of which, 500 responded to the follow-up survey. The Centre for Epidemiologic Studies-Depression Scale and Pittsburgh Sleep Quality Index were filled out by the participants, and their responses were analysed by logistic regression to evaluate the risk of depression or sleep problems. We collected exact aggressive words encountered at work over the past year as a dependent variable and classified it into four types using text mining, such as words criticizing one's performance.
The follow-up rate was 63%. Exposure to words threatening one's life showed a significant relationship with the risk of depression (odds ratio OR = 13.94, 95% confidence interval CI = 1.76-110.56). The exposure to words criticizing one's job performance is significantly related to the risk of sleep disturbance (OR = 5.56, 95% CI = 2.08-14.88).
These findings suggest that different contents of verbal aggression can have different impacts on workers' health. This indicates that not only overtly threatening and abusive language but also words related to one's performance can be a risk factor for workers, depending on how they are delivered. To mitigate the adverse effects, promoting effective communication and cultivating psychological detachment from work may be beneficial.
Power generation performance and long‐term durability of ammonia‐fueled solid oxide fuel cell (SOFC) systems are investigated with SOFC stacks consisting of 30 planar anode‐supported cells. SOFC ...systems with three different operation modes are employed: direct ammonia, external decomposition and autothermal decomposition. A novel BaO/Ni/Sm2O3/MgO catalyst is newly developed for the external ammonia cracker, whereas a Co‐Ce‐Zr composite oxide catalyst is used for the autothermal ammonia cracker. Initial performance measurement and 1,000 h long‐term durability test of the stacks are conducted. The stack fueled with direct ammonia achieves 1 kW power output with 52% direct current (DC) electrical efficiency; a slight decrease in its performance compared with the stack with the mixture fuel of hydrogen and nitrogen is attributed to the decrease in the stack temperature caused by the endothermic ammonia decomposition reaction. The external ammonia cracker helps to maintain the stack temperature, improving the initial performance of the stack. The stack performance with the autothermal ammonia cracker is also comparable to those with the other operation modes. It is also demonstrated that the stacks fueled with ammonia have excellent stability during the long‐term tests and 57% energy conversion efficiency at ca. 700 W electrical output is achieved with the external ammonia cracker.
The indications for endoscopic submucosal dissection (ESD) for duodenal tumors have not yet been established. We reviewed our experience of ESD performed for duodenal tumors. We analyzed the data of ...a total of 13 patients with 14 duodenal lesions (excluding papillary lesions) comprising 2 early cancers, 5 adenomas, and 7 neuroendocrine tumors, who were treated by ESD between 2005 and 2011. The mean tumor diameter was 12.7 ± 14.8 mm. En bloc resection was achieved in 85.7% of the cases. The procedure time was 89.1 ± 64.6 minutes. Intraoperative perforation occurred in three cases. The mean length of postoperative hospitalization was 8.4 ± 2.4 days. Because ESD for duodenal lesions was associated with a higher incidence of perforation than ESD for lesions in other locations (stomach, esophagus, and colon) reported previously, its use for duodenal lesions should be considered with caution.
The relationship between oral health and the development of Alzheimer’s disease (AD) in the elderly is not yet well understood. In this regard, the association between aging or neurodegeneration of ...the trigeminal nervous system and the accumulation of amyloid-β(1–42) (Aβ42) oligomers in the pathogenesis of AD is unknown. We focused on selective autophagy in the trigeminal mesencephalic nucleus (Vmes) and the diffusion of Aβ42 oligomers with respect to aging of the trigeminal nervous system and whether the degeneration of Vmes neurons affects the diffusion of Aβ42 oligomers. We used female 2- to 8-mo-old transgenic 3xTg-AD mice and App
NL-G-F
knock-in mice and immunohistochemically examined aging-related changes in selective autophagy and Aβ42 oligomer processing in the Vmes, which exhibits high amyloid-β (Aβ) expression. We induced degeneration of Vmes neurons by extracting the maxillary molars and examined the changes in Aβ42 oligomer kinetics. Autophagosome-like membranes, which stained positive for Aβ, HO-1, and LC3B, were observed in Vmes neurons of 3xTg-AD mice, while there was weak immunoreactivity of the membranes for intraneuronal Aβ in App
NL-G-F
mice. By contrast, there was strong immunopositivity for extracellular Aβ42 oligomers with the formation of Aβ42 oligomer clusters in App
NL-G-F
mice. The expression of Rubicon, which indicates age-related deterioration of autophagy, increased the diffusion of Aβ42 oligomer with the age of Vmes neurons. Tooth extraction increased the extracellular immunopositivity for Aβ42 oligomers in App
NL-G-F
mice. These results suggest that autophagy maintains homeostasis in Vmes neurons and that deterioration of autophagy due to aging or neurodegeneration leads to the diffusion of Aβ42 oligomers into the extracellular space and possibly the development of AD.
The purpose of this study was to investigate the effects of the
T1470A polymorphism (rs1049434) on power-oriented performance and lactate concentration during or after cycling sprints in Japanese ...wrestlers. Participants (199 wrestlers and 649 controls) were genotyped for the
T1470A genotype (rs1049434) using the TaqMan
Assay. All wrestlers were international (n=77) or national (n=122) level athletes. Among them, 46 wrestlers performed 2 anaerobic performance tests, a 30-s Wingate Anaerobic test (WAnT) and a series of 10 maximal effort 10-s sprints on a cycle ergometer. Blood lactate levels were measured before, during, and after the tests. In the A-allele recessive model (AA vs. TA+TT), the frequency of the AA genotype was significantly higher in all wrestlers than in controls (p=0.037). Wrestlers with AA genotype had lower blood lactate concentrations than those with TA+TT genotype at 10 min after the WAnT and following the 5
and the final set of repeated cycling sprints (p<0.05). The AA genotype of the
T1470A polymorphism is over-represented in wrestlers compared with controls and is associated with lower blood lactate concentrations after 30-s WAnT and during intermittent sprint tests in Japanese wrestlers.
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