Chains of Carbon Nanotetrahedra/Nanoribbons

Flattening of a carbon nanotube results in the formation of a carbon nanoribbon with well-defined edges. In addition, a switching of the flattening direction by about a right angle yields a carbon nanotetrahedron at the switching point in a nanoribbon. Here, we report that chains of carbon nanotetrahedra/nanoribbons are formed via sequential switching of the flattening direction of multiwalled carbon nanotubes, in which neighboring two nanotetrahedra are connected by a short nanoribbon, namely a flattened nanotube. We suggest that the formation of nanotetrahedra chains is caused by a quasi-periodic instability of catalyst iron nanoparticles during the chemical vapor deposition growth. In addition, two adjoining carbon nanotetrahedra were found

Intercellular bridges for cell-cell communication

In multicellular organism, intercellular communication is essential for maintenance of life activity. The intercellular communication includes direct and indirect crosstalk such as gap junction and ligand-receptor interaction, pectively. Recently, a new type of cell-cell communication for intercellular exchange of signaling molecules via a nanotube bridge structures, referred to as a tunneling nanotubule (TNT), between nearby cells was identified. In this review,we roduce current understanding of TNT having received a lot of attention as a novel direct cell-cell communication method

Optimizing Growth Conditions for Coaxial Multi-Walled Carbon Nanotubes

Coaxial multi-walled carbon nanotubes have a multi-layered structure in which a core multi-walled carbon nanotube is grown inside a sheath multi-walled nanotube from a metal-catalyst nanoparticle. In this paper, we report the optimum conditions to grow coaxial multi-walled carbon nanotubes by chemical vapor deposition. The coaxial nanotubes are studied by means of transmission electron microscopy to reveal their crystallinity and morphology. Our results show that chemical vapor deposition growth at around 1000°C with a 0.04–0.07 mg/cm^3 dose of palmitic acid yields the best result

SIZE EFFECTS ON MAGNETIC PROPERTY AND CRYSTAL STRUCTURE OF MN3O4 NANOPARTICLES IN MESOPOROUS SILICA

Mn3O4 nanoparticles with particle sizes of 7.8, 11.4, and 18.3 nm were synthesized in the pores of mesoporous silica, and their crystal structure and magnetic properties were investigated. The powder X-ray diffractions at room temperature indicated that the crystal structural symmetry was the same as that for bulk crystal, and the lattice constants deviated from those for bulk crystal, which depended on the particle size. In addition, compared with the bulk crystal, the Jahn-Teller distortion for the nanoparticles was suppressed and decreased with decreasing the particle size. The coercive field for 7.8 nm was rather smaller than those for 11.4 and 18.3 nm. The nanoparticles with 11.4 and 18.3 nm exhibited pronounced three kinds of magnetic transition temperatures, whereas the susceptibility for 7.8 nm indicated the existence of two transition temperatures. These experimental results suggested that the Mn3O4 nanoparticles have a strong correlation between crystallographic structure and magnetic property, and the characteristic magnetic size effects are attributed to the reduction of Jahn-Teller distortion.The 21st International Conference on Magnetism (ICM2018), July 15-20, 2018, San Francisco, US

人工種苗生産されたキジハタ仔稚魚の遊泳・摂餌関連形質の発達

人工種苗生産されたキジハタ仔稚魚について、遊泳と摂餌に関する形質の発育を記載し発育段階の設定を行った。遊泳では以下の5段階に分けられた：1）遊泳未発達期（D0～1）－遊泳に関する形質は出現しない時期；2）浮遊および胸鰭発達期（D2～9）－肩帯の構成要素が出現する時期；3）尾鰭推進準備期（D10－12～15－17）－脊索末端の上屈が開始・完了する時期；4）尾鰭＋体全体推進期（D15－17～20－22）－脊椎要素が出現・完成し、臀鰭と腹鰭、尾鰭の鰭条が定数になる時期；5）遊泳機能完成期（D20－22～）－稚魚としての遊泳能力が獲得される時期。摂餌でも以下の5段階に分けられた：1）摂餌未発達期（D0～2）－未開口で内部栄養に依存する時期；2）初期吸込み期（D3～9）－口腔を形成する要素が出現し、開口したことで陰圧を利用した摂餌が可能となる時期；3）吸込み摂餌期（D10－12～20－22）－口腔を形成する要素の化骨により吸込み機能が強化され、上顎に占める前上顎骨の長さが一定になることで口の開閉能力が増す時期；4）吸込み＋噛みつき期（D20－22～35）－摂餌関連形質はすべて出現・完成し、顎歯だけでなく前鋤骨歯や口蓋骨歯も出現する時期；5）摂餌機能完成期（D35～）－稚魚としての摂餌能力が獲得される時期。本研究の結果から、本種の初期飼育の困難さの一因が、内部栄養から外部栄養に切り替わる期間の遊泳・摂餌関連形質の発育の遅さであることが判明した。さらにD30を過ぎると、群れを形成するとともに、共食いの萌芽行動である「J字」ポーズが見られた。本研究の結果は、今後の本種をふくむハタ科魚類の種苗生産の新しい管理手法の開発に資すると期待される。Based on the development of swimming- and feeding-related characters, ontogenetic intervals of larvae and juveniles were investigated for hatchery-reared red spotted grouper, Epinephelus akaara. Five phases each were recognized for the development of swimming and feeding functions as follows. Swimming: 1) the phase with less active swimming (hatching to 1 day after hatching, D1); 2) the phase with body control by pectoral fins (D2～D9); 3) the phase with preparation of caudal fin propulsion (D10-12～D15-17); 4) the phase with caudal fin and whole body propulsion (D15-17～D20-22); 5) the phase of juvenile swimming mode (beyond D20-22). Feeding: 1) the phase with endogenous nutrient (hatching to D2); 2) the phase with initial feeding of sucking (D3～D9); 3) the phase with sucking ability increasing (D10-12～D20-22); 4) the phase with sucking and initial biting (D20-22～D35); 5) the phase of juvenile feeding mode (beyond D35). The present study revealed that the difficulties of larval rearing of the species would be partly due to the delay of development of characters related to swimming- and feeding-functions during the changeover from endogenous to exogenous feeding. After D30, the juveniles with functional swimming- and feeding-mode showed both swimming in schools and posing with “J-posture”, the latter being considered to be the onset of cannibalistic behavior. The results of present study are expected to contribute to the improvement of larval rearing system in groupers.今井 智・小金隆之・山下貴示: 国立研究開発法人水産研究・教育機構瀬戸内海区水産研究所資源生産部Satoshi IMAI, Takayuki KOGANE, Takashi YAMASHITA: Stock Enhancement and Aquaculture Department, National Research Institute of Fisheries and Environment of Inland Sea, Fisheries Research and Education Agency河野 博: 東京海洋大学学術研究院海洋環境科学部門 魚類学研究室Hiroshi KOHNO: Laboratory of Ichthyology, Department of Ocean Sciences, Tokyo University of Marine Science and Technology (TUMSAT

Fungicidal Action of Hydroxyl Radicals Generated by Ultrasound in Water

It is well known that hydroxyl radicals are generated by ultrasound in water. This study with an electron spin resonance spin-trapping technique showed that hydroxyl radical generation was positively correlated with ultrasound duration and water temperature. The clear fungicidal action against Trichophyton spp. evident by studying cultured cells and the degradation of cytoplasmic and surface structures observed by transmission and scanning electron microscopy suggest that ultrasound in hot water is effective for sterilization of dermatophyte contamination and could be effective for the treatment of tinea infection

Characteristic Size Effects on the Crystallographic Structure and Magnetic Properties of RMnO3 (R = Eu, Gd, Tb, Dy) Nanoparticles

We synthesized lanthanoid manganese oxide RMnO3 (R = Eu, Gd, Tb, and Dy) nanoparticles with particle sizes ranging from approximately 6.5 to 23 nm and investigated both their crystal structure and magnetic properties. The RMnO3 nanoparticles showed a strong correlation between crystal structure and magnetic properties, and particle size effects on these properties vary owing to the different atomic radii of the lanthanoid ions. The magnetic properties of all of the nanoparticles exhibited significant changes as the lattice constants changed at characteristic sizes that depend on the lanthanoid ionic radius; however, the characteristic size for magnetic properties corresponded to the magnitude of the orthorhombic distortion b/a = 1.10, regardless of the lanthanoid ionic radius. With decreasing particle size, EuMnO3, GdMnO3, and TbMnO3 nanoparticles induced tensile strain of MnO6 octahedra, whereas compressive strain occurred in DyMnO3 nanoparticles. The deformation of MnO6 octahedra changed the magnetic interactions, resulting in changes in the magnetic properties. As the particle size decreased, for R = Eu, Gd, and Tb, the magnetic properties, such as transition temperature, coercive field, and blocking temperature, decreased; conversely, these values increased in DyMnO3. The distortion of the unit cell induced changes in the magnetic ordering state due to decreasing particle size

Kinematics of SiO J=8-7 Emission towards the HH 212 Jet

We present SiO J=8-7 (347.3 GHz) observations towards HH 212 using the ASTE telescope. Our observations with a 22''-diameter beam show that the SiO emission is highly concentrated within 1' of the driving source. We carefully compare the SiO observations with archival H_2 1-0 S(1) images and published H_2 echelle spectra. We find that, although the SiO velocities closely match the radial velocities seen in H_2, the distribution of H_2 and SiO emission differ markedly. We attribute the latter to the different excitation conditions required for H_2 and SiO emission, particularly the higher critical density (n_H2 ~10^8 cm^-3) of the SiO J=8-7 emission. The kinematic similarities imply that the H_2 and SiO are associated with the same internal working surfaces. We conclude that the SiO J=8-7 emission has a potential to probe the jet/wind launching region through interferometric observations in the future, particularly for the youngest, most deeply embedded protostars where IR observations are not possible.Comment: 6 pages, 4 figures, accepted to PAS