Epitaxial contact Andreev reflection spectroscopy of NbN/Co₂FeSi layered devices

We investigated the spin polarization P of Co-based Heusler alloy Co2FeSi by epitaxial contact Andreev reflection (ECAR) spectroscopy using epitaxially grown superconductor NbN and Heusler alloy Co2FeSi layered devices. Ferromagnetic Co2FeSi possesses the highest Curie temperature (TC ? 1100 K) and the largest spontaneous magnetic moment (ps ? 6 μB) in the class of Heusler alloys. The ECAR measurements revealed that the P value of Co2FeSi was 54 ± 2% with a finite barrier parameter Z, indicating that an intrinsic P value in ECAR spectroscopy would exceed reported values in point-contact Andreev reflection spectroscopy. We therefore established not only the epitaxial integration of ferromagnetic Co2FeSi with superconductor NbN on an MgO substrate but also the fabrication and evaluation techniques of their ECAR devices. This highly versatile superconducting spintronic system enables fundamental superconducting spintronic studies, and it is also a candidate for practical superconducting spintronic devices

Seasonal Changes in Ovarian Response to Photoperiods in Orange-Red Type Medaka : Reproductive Biology

Volume: 6Start Page: 943End Page: 95

Effects of Water Temperature and Photoperiod on the Beginning of Spawning Season in the Orange-red Type Medaka : Reproductive Biology

Volume: 5Start Page: 1059End Page: 106

エゾアワビ卵巣におけるビテリンの産生と蓄積過程の免疫組織学的解析

Ovarian follicle cells are the site of yolk protein synthesis in the Ezo abalone Haliotis discus hannai. In this study, histological observations of ovarian follicle cells were conducted in H. discus hannai by immunocytochemical and in situ hybridization methods focusing on their function of yolk protein synthesis. An antibody raised against purified yolk protein (vitellin, Vn) recognized yolk granules in oocytes, and ovarian follicle cells adjacent to the oocytes under yolk accumulation were stained positively with both anti-Vn antibody and an antisense probe for vitellogenin (the precursor for vitellin, Vtg) mRNA. These results indicate that the abalone Vtg gene is transcribed and translated in the ovarian follicle cells. In oocytes in the early phase of yolk accumulation, positive reactions with the antibody appeared first in the stalk part, and the follicle cells adjacent to the stalk were also stained positively. These observations imply local transportation of yolk protein from the follicle cells to the oocyte through an extracellular space around the oocyte stalk. Ovarian follicle cells changed their morphological characteristics and reactivity to the antibody with close relationships with the stages of the adjacent oocyte, which suggests the presence of functional interactions between follicle cells and oocytes in the course of yolk protein synthesis and accumulation.エゾアワビ卵巣濾胞細胞（濾胞細胞）の卵黄タンパク質（ビテリン、Vn）合成と卵母細胞へのVn蓄積過程について、抗Vn抗体による免疫染色とVn前駆体遺伝子のin situ ハイブリダイゼーションで組織学的に検討した。その結果、前駆体遺伝子が濾胞細胞で転写、翻訳されることが示され、合成された卵黄タンパク質は濾胞細胞と卵母細胞が接する卵柄部で卵母細胞内に輸送されると示唆された。また濾胞細胞の形態と抗Vn抗体への反応性は隣接する卵母細胞の発達と密接に関連し、Vn合成と蓄積において濾胞細胞と卵母細胞間に相互作用が存在すると推定された

A novel paramyxean parasite, Marteilia granula sp. nov. (Cercozoa), from the digestive gland of Manila clam Ruditapes philippinarum in Japan

A paramyxean parasite infection was observed in the epithelial cells of the stomach, intestine, and digestive diverticula of Manila clam Ruditapes philippinarum collected from Odawa Bay, Japan. The mean detection frequency between April 2010 and September 2011 as revealed by histology was 8.9% with a maximum monthly frequency of 28.6%, but remarkable mass mortality was not recognized during the study period. Sporulation of the parasites involves repeated production of intracellular cells, and a primary cell contains 8 secondary cells, in which 4 multicellular spore cells are produced. Several large eosinophilic granules formed in the cytoplasm of secondary cells during the final maturation process. Transmission electron microscopy (TEM) revealed that spore cells consisted of the innermost, intermediate and outermost cells, indicating that this parasite is a member of the genus Marteilia. TEM observations also revealed that the cell membrane of mature spores was lined with an electron-dense monolayer, which has not been reported from other species in the genus Marteilia. Determined SSU rRNA gene sequence of this parasite was apparently different from previously described Marteilia species, and this species was identified as Marteilia granula n. sp., a new species in the genus Marteilia, Order Paramyxida, Phylum Cercozoa. Our results identify for the first time the parasite species of the genus Marteilia infecting the Manila clam in Japan.13 page(s