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Magnetotelluric and seismic data, collected during the MELT experiment at the southern East Pacific Rise, constrain the distribution of melt beneath this mid-ocean-ridge spreading centre and also the evolution of the oceanic lithosphere during its early cooling history. Here we focus on structures imaged at distances ∼100 to 350 km east of the ridge crest, corresponding to seafloor ages of ∼1.3 to 4.5 million years (Myr), where the seismic and electrical conductivity structure is nearly constant and independent of age. Beginning at a depth of about 60 km, we image a large increase in electrical conductivity and a change from isotropic to transversely anisotropic electrical structure, with higher conductivity in the direction of fast propagation for seismic waves. Conductive cooling models predict structure that increases in depth with age, extending to about 30 km at 4.5 Myr ago. We infer, however, that the structure of young oceanic plates is instead controlled by a decrease in water content above a depth of 60 km induced by the melting process beneath the spreading centre. [ABSTRACT FROM AUTHOR]

The most prominent hotspot in the South Atlantic is Tristan da Cunha, which is widely considered to be underlain by a mantle plume. But the existence, location and size of this mantle plume have not been established due to the lack of regional geophysical observations. A passive seismic experiment using ocean bottom seismometers aims to investigate the lithosphere and upper mantle structure beneath the hotspot. Using the Ps receiver function method we calculate a thickness of 5 to 8 km for the oceanic crust at 17 ocean-bottom stations deployed around the islands. Within the errors of the method the thickness of the oceanic crust is very close to the global mean. The Tristan hotspot seems to have contributed little additional magmatic material or heat to the melting zone at the mid-oceanic ridge, which could be detected as thickened oceanic crust. Magmatic activity on the archipelago and surrounding seamounts seems to have only affected the crustal thickness locally. Furthermore, we imaged the mantle transition zone discontinuities by analysing receiver functions at the permanent seismological station TRIS and surrounding OBS stations. Our observations provide evidence for a thickened (cold) mantle transition zone west and northwest of the islands, which excludes the presence of a deep-reaching mantle plume. We have some indications of a thinned, hot mantle transition zone south of Tristan da Cunha inferred from sparse and noisy observations, which might indicate the location of a Tristan mantle plume at mid-mantle depths. Sp receiver functions image the base of lithosphere at about 60 to 75 km beneath the islands, which argues for a compositionally controlled seismological lithosphere-asthenosphere boundary beneath the study area. [ABSTRACT FROM AUTHOR]

Presents a guideline on how to effectively and appropriately perform catheter intervention in coronary artery lesion in Kawasaki disease on the basis of the information regarding evaluation of the diagnosis and the therapy reported in Japan and overseas. Natural history of coronary artery lesion in Kawasaki disease; Catheter intervention for patients with Kawasaki disease.

Nishinoshima, a volcanic island in the Ogasawara (Bonin) island arc, has intermittently erupted since November 2013 after a quiescence of nearly 40 years. The three-dimensional (3D) magnetization structure of this growing volcanic island was investigated for the first time by acquiring aeromagnetic data with an unmanned aerial vehicle (UAV) system and subjecting the data to a 3D regularized inversion. The aeromagnetic surveys, in September 2018 and June 2019, covered an area of about 3 km × 3 km that included the emergent part of Nishinoshima volcano. We extracted the magnetic anomaly induced by the magnetization structure from the observations and estimated the magnetization structure from the anomaly by applying the 3D inversion, which combines L1 and L2 norm regularizations. We conducted a cross-validation to simultaneously determine optimum values of a regularization parameter and a hyperparameter. We found that Nishinoshima volcano had an average magnetization of about 3.0 A/m and that two more strongly magnetized bodies existed as of 2019 beneath the summit crater and the northeastern flank at depths several hundred meters below the surface. These features may represent massive bodies of old chilled magma. This study demonstrated the utility of this relatively safe and inexpensive observation method and this data analysis method for investigating the magnetic structure of remote volcanic islands. Repeated future surveys of this type may enable us to monitor volcanic activities that affect the magnetization structure of volcanoes. • Unmanned aeromagnetic surveys of an isolated volcanic island were conducted. • 3D magnetization structure of Nishinoshima volcano in 2019 was estimated. • Cross-validation procedures were used to determine parameters of the 3D inversion. • Magnetized bodies were found beneath the summit crater and the flank of the island. [ABSTRACT FROM AUTHOR]

Presents the case of a boy with human herpesvirus 6 (HHV-6) fulminant hepatic failure who was treated by living donor liver transplantation. Medical history of the patient; Details of the identification of an etiologic agent for the disease; Background on the detection of HHV-6 DNA in serum samples.

We present a case of a 12-year-old boy with a rare form of cardiac anomaly, isolated double-orifice mitral valve. He was referred to our hospital at 1.5 years old because of heart murmur. Two-dimensional echocardiography showed double-orifice mitral valve without any associated cardiac anomalies. He has been followed carefully without any medication for 11 years. He has had no symptoms and an excellent natural course thus far.

Aim: To elucidate a clinical difference between patients with Kawasaki disease documented with Yersinia pseudotuberculosis infection and patients with Kawasaki disease without Yersinia pseudotuberculosis infection., Patients and Methods: From January 1985 to July 2004, 452 patients were diagnosed with Kawasaki disease. Forty-two patients had elevated antibody titres of Yersinia pseudotuberculosis and/or positive stool culture (Yersinia-positive group). Three hundred and thirty patients had no elevated antibody titres (Yersinia-negative group). We compared the clinical characteristics retrospectively., Results: The age of onset in the Yersinia-positive group (3.05+/-2.20 y) was significantly higher than that in the Yersinia-negative group (2.31+/-2.05 y) (p=0.03). The age-adjusted statistical analysis demonstrated that the incidence of coronary artery lesions (dilatations plus aneurysms) in the Yersinia-positive group (22/42, 52.4%) was significantly higher than in the Yersinia-negative group (105/330, 31.8%) (p=0.001), and the incidence of additional administration of immunoglobulin in the Yersinia-positive group (13/36, 36.1%) was significantly higher than in the Yersinia-negative group (41/256, 16.0%) (p=0.004)., Conclusion: Our data suggest that Yersinia pseudotuberculosis infection might play a role in the developing mechanism of poor response to therapy and the tendency to develop coronary artery lesions in Kawasaki disease patients.

We report a case of an eight-year-old boy with Kawasaki disease (KD) who had a giant aneurysm with stenotic lesions located in the right coronary artery, and was treated by transcatheter implantation of a polytetrafluoroethylene(PTFE)-covered stent. Follow-up coronary angiography showed good coronary blood flow. To the best of our knowledge, this is the first child with KD who underwent covered-stent implantation in a coronary aneurysm. Although close follow-up is mandatory, because the long-term outcome is unclear, implantation of a covered stent in a giant aneurysm appears to be a promising treatment option., (Copyright 2006 Wiley-Liss, Inc.)