Search

Large variations in the maximum earthquake magnitude ( M max ) have been observed among the world's subduction zones. There is still no universal relationship between M max and a given subduction-zone parameter, such as plate age, plate dip angle, or plate velocity, which suggests that multiple parameters control M max . Here, we conduct exhaustive variable selections that are based on three evaluation criteria; leave-one-out cross-validation errors (LOOCVE), Akaike information criterion (AIC), and Bayesian information criterion (BIC) to determine the combination of subduction-zone parameters that best explains M max . Multiple linear regression analyses are applied using 18 subduction-zone parameters as potential candidates for the explanatory variables of M max . The minimum BIC is obtained when five variables (trench sediment thickness, existence of an accretionary prism, upper-plate crustal thickness, bending radius of the subducting oceanic plate, and trench depth) are selected as explanatory variables; each variable contributes positively to M max . Minimum LOOCVE and AIC values are obtained when eight variables (the five parameters for BIC, plus the along-strike plate convergence rate, age of the subducting plate, and maximum depth of the subducting plate) are selected. Our selection of the trench sediment thickness and plate bending radius contributing to M max is consistent with previous studies. The results show that increasing upper-plate crustal thickness results in a large M max . In addition to smoothing the subducting-plate interface via subducted sediments, along-dip extension of the crustal area along the convergent plate boundary would be important for generating a large earthquake. [ABSTRACT FROM AUTHOR]

Purpose: After our group described the first remote-access thyroidectomy series in 2000, the procedure has been further developed. Although a thoracoscopic approach with a conventional open cervical incision for thyroid goiters with mediastinal extension has been performed at many institutions, remote-access thyroidectomy for cervicomediastinal goiters has not been established. We have performed combined thoracoscopic and axillary subcutaneous endoscopic thyroidectomies (axillo-thoracic endoscopic thyroidectomies). Here, we describe a novel technique for performing a remote-access thyroidectomy for a cervicomediastinal goiter (CMG). Patients and methods: The patients with CMGs who agreed to an axillo-thoracic endoscopic thyroidectomy at one of two hospitals in Japan underwent a remote-access thyroidectomy. Results: We performed the axillo-thoracic endoscopic right or left hemithyroidectomy successfully, but most of the patients did not require the thoracoscopic procedure. None of the patients had complications, and none was converted to an open thyroidectomy. Conclusions: Most thyroid goiters with substernal extension can be removed by the axillary approach, but some cases require a thoracoscopic approach. The novel approach described herein (axillo-thoracic endoscopic thyroidectomy) enables the safe excision of a CMG with high patient satisfaction for selected patients. [ABSTRACT FROM AUTHOR]

Pancreatic serous neoplasms are rare tumors that are usually benign. However, histopathological differentiation between benign (serous cystadenoma) and malignant (serous cystadenocarcinoma) lesions is difficult. We present the case of a patient with pancreatic serous cystadenocarcinoma that was diagnosed with liver metastasis 7 years after the resection of the primary serous neoplastic lesion. A woman in her 60 s was diagnosed with pancreatic serous cystadenoma based on imaging and histopathological examination findings. The tumor was resected, and the patient was followed up every 6 months to monitor tumor progression. At 7 years after the resection of the primary lesion, liver tumors showing marked flare-like contrast enhancements were detected on arterial phase computed tomography findings and on dynamic magnetic resonance imaging findings acquired 60 s after the administration of a contrast agent. Laparoscopic segmental hepatectomy of S4 and S6 was performed to resect these tumors. Histopathological examination revealed that these tumors were metastatic and developed from the primary lesion. Therefore, a diagnosis of serous cystadenocarcinoma was confirmed. The flare-like contrast enhancement around the metastatic liver lesions on computed tomography and dynamic magnetic resonance images may be an indicator of serous cystadenocarcinoma with liver metastasis that could assist in diagnosis. [ABSTRACT FROM AUTHOR]

Background: Surgical management has not been encouraged in patients with trisomy 18 (T18) and congenital heart diseases due to poor survival. This study aimed to investigate (1) the appropriateness of palliative surgeries followed by intracardiac repair (ICR) (i.e., two-stage ICR) for patients with a large ventricular septal defect (VSD) and T18, and (2) its impact on their long-term outcomes. Methods: Medical charts of patients with VSD and T18 who underwent two-stage ICR at the Japanese Red Cross Medical Center between January 2005 and December 2019 were retrospectively reviewed. Demographic data, timing, and types of palliative surgeries, information related to ICR, peri- and postoperative clinical information, postoperative survival, and cause of death were collected. The long-term prognosis of patients treated with two-stage ICR was compared with that of patients treated with primary ICR and palliative surgery without ICR. Results: Overall, 18 (2 male, 16 female) patients underwent two-stage ICR. Pulmonary artery banding was the initial palliative surgery in all patients after a median duration of 19.5 (range 6–194) days of life. The median age and the mean body weight at the time of ICR were 18.2 (7.6–50.7) months and 6.0 ± 1.0 kg, respectively. The mean pulmonary artery pressure and pulmonary vascular resistance index before ICR were 19.1 ± 7.3 mmHg and 3.4 ± 2.0 U m2, respectively. Overall, 17/18 (94%) patients were discharged after ICR. Fourteen (78%) patients were alive during data collection. None of the patients died of cardiac insufficiency, and the median duration of survival was 46.3 (14.3–186.4) months since birth. Most patients required cardiac medications rather than pulmonary vasodilators at the last follow-up. During the study period, three patients underwent primary ICR, and 46 underwent palliative surgery without ICR. Of those who underwent primary ICR, two died in the hospital on the first and 48th day following ICR, and the third died 179 days after the ICR. The Log-rank test revealed a significantly longer survival for the patients treated with two-stage ICR compared with those treated with palliative surgery without ICR (P = 0.003). Conclusion: Two-stage ICR improves the long-term survival of patients with VSDs and T18. This safe surgical strategy can also prevent pulmonary hypertension in such patients. [ABSTRACT FROM AUTHOR]

Potassium (K) and radiocaesium (RCs) were chemically extracted from soils derived from granite (G soils) and sedimentary rock (S soils) in Fukushima, Japan. The extractants employed were 1 M HNO3, concentrated HNO3, and HF + HClO4. As S soils contain a lower amount of trioctahedral 2:1 phyllosilicates than G soils, the RCs/K ratio was higher in S soils than in G soils with 1 M HNO3 extraction, indicating that the potential risk of soil-to-plant transfer of RCs is higher in S soils than in G soils. In conclusion, information about surface geology is important in predicting the spatial pattern of soil characteristics related to transferability of RCs. [ABSTRACT FROM AUTHOR]

Here, we investigate a possible scenario of surface seawater evolution in the numerical simulations of surface plate motion driven by mantle dynamics, including thermo-chemical convection and water migration, from the early to present-day Earth to constrain the total amount of water in the planetary system. To assess the validity of two hypotheses of the total amount of water inferred from early planetary formation processes and mineral physics, we examine the model sensitivity to the total water in the planetary system (both surface and deep interior) up to 15 ocean masses. To explain the current size of the reservoir of surface seawater, the predictions based on the numerical simulations of hydrous mantle convection suggest that the total amount of water should range from 9 to 12 ocean masses. Incorporating the dense hydrous magnesium silicate (DHMS) with a recently discovered hydrous mineral at lower mantle pressures (phase H) indicates that the physical mechanism of the mantle water cycle would not be significantly influenced, but the water storage region would be expanded in addition to the mantle transition zone. The DHMS solubility field may have a limited impact on the partitioning of water in the Earth’s deep mantle. [ABSTRACT FROM AUTHOR]