Megumi Matsumoto

IGF-related proteins at birth in a case of antenatally diagnosed Silver-Russell syndrome.

We report here a case with severe intrauterine growth restriction from the first trimester and clinical features of Silver-Russell syndrome including microcephaly, low-set ear, atrial septum defect, ventricular septum defect, diaphragmatic relaxation, and rocker bottom feet. Silver-Russell syndrome is thought to result from deletion of the distal long arm of chromosome 15 on which the IGF-I receptor (IGF-IR) gene is located. We measured both the maternal and cord blood levels of GH, IGF-I, and IGF-binding protein and performed an immunohistochemical study of IGF-IR in the placenta to investigate whether these IGF-related proteins were affected in this patient. The hormonal level of these proteins did not significantly differ from normal neonates, and immunohistochemical analysis suggested IGF-IR protein levels in the placenta were comparable to normal term neonates. These results support the hypothesis that growth insufficiency could occur in patients with monosomy of the distal long arm of chromosome 15 and suggest a critical threshold for IGF-related fetal growth in early pregnancy.

Discovery of moganite in a lunar meteorite as a trace of H2O ice in the Moon’s regolith

Discovery of moganite in a lunar meteorite indicates the possibility of H2O ice accumulated in the Moon’s regolith. Moganite, a monoclinic SiO2 phase, has been discovered in a lunar meteorite. Silica micrograins occur as nanocrystalline aggregates of mostly moganite and occasionally coesite and stishovite in the KREEP (high potassium, rare-earth element, and phosphorus)–like gabbroic-basaltic breccia NWA 2727, although these grains are seemingly absent in other lunar meteorites. We interpret the origin of these grains as follows: alkaline water delivery to the Moon via carbonaceous chondrite collisions, fluid capture during impact-induced brecciation, moganite precipitation from the captured H2O at pH 9.5 to 10.5 and 363 to 399 K on the sunlit surface, and meteorite launch from the Moon caused by an impact at 8 to 22 GPa and >673 K. On the subsurface, this captured H2O may still remain as ice at estimated bulk content of >0.6 weight %. This indicates the possibility of the presence of abundant available water resources underneath local sites of the host bodies within the Procellarum KREEP and South Pole Aitken terranes.

Coherent interface structures and intergrain Josephson coupling in dense MgO/Mg2Si/MgB2 nanocomposites

Many efforts are under way to control the structure of heterointerfaces in nanostructured composite materials for designing functionality and engineering application. However, the fabrication of high-quality heterointerfaces is challenging because the crystal/crystal interface is usually the most defective part of the nanocomposite materials. In this work, we show that fully dense insulator (MgO)/semiconductor(Mg2Si)/superconductor(MgB2) nanocomposites with atomically smooth and continuous interfaces, including epitaxial-like MgO/Mg2Si interfaces, are obtained by solid phase reaction between metallic magnesium and a borosilicate glass. The resulting nanocomposites exhibit a semiconductor-superconducting transition at 36 K owing to the MgB2 nanograins surrounded by the MgO/Mg2Si matrix. This transition is followed by the intergrain phase-lock transition at ∼24 K due to the construction of Josephson-coupled network, eventually leading to a near-zero resistance state at 17 K. The method not only provides a s...