• Title/Summary/Keyword: Hokkaido University

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In-situ Observation of Hydride Stability of Vanadium Alloys in Electron Microscope

  • Ohnuki, S.;Takase, K.;Yashiki, K.;Hamada, K.;Suda, T.;Watanabe, S.
    • Applied Microscopy
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    • v.36 no.spc1
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    • pp.57-61
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    • 2006
  • High-resolution microscopy was applied for surveying hydride stability in Vanadium alloys, which are candidate for hydrogen storage materials of advanced hydrogen energy systems. $V_2H$ hydride in V alloys was stable at room temperature under the vacuum condition, but it was decomposed during heating up to $100^{\circ}C$. It was confirmed from HRTEM image and FFT that $V_2H$ has a BCT structure, where hydrogen atoms locate at octahedral sites. Crystal orientation was <110> beta// <110> mat., and lattice strain is about 10%. After the decomposition of the hydride, relatively large lattice expansion was observed in the matrix, which suggests that hydrogen atoms should be trapped by lattice defects and included in the matrix. Intensive electron beam also enhanced the decomposition.

Growth and Photosynthetic Responses of Cuttings of a Hybrid Larch (Larix gmelinii var. japonica x L. kaempferi) to Elevated Ozone and/or Carbon Dioxide

  • Koike, Takayoshi;Mao, Qiaozhi;Inada, Naoki;Kawaguchi, Korin;Hoshika, Yasutomo;Kita, Kazuhito;Watanabe, Makoto
    • Asian Journal of Atmospheric Environment
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    • v.6 no.2
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    • pp.104-110
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    • 2012
  • We studied the effects of elevated ozone ([$O_3$]) and $CO_2$ concentrations ([$CO_2$]) on the growth and photosynthesis of the hybrid larch $F_1(F_1)$ and on its parents (the Dahurian larch and Japanese larch). $F_1$ is a promising species for timber production in northeast Asia. Seedlings of the three species were grown in 16 open top chambers and were exposed to two levels of $O_3$ (<10 ppb and 60 ppb for 7 h per day) in combination with two levels of $CO_2$ (ambient and 600 ppm for daytime) over an entire growing season. Ozone reduced the growth as measured by height and diameter, and reduced the needle dry mass and net photosynthetic rate of $F_1$, but had almost no effect on the Dahurian larch or Japanese larch. There was a significant increase in whole-plant dry mass induced by elevated [$CO_2$] in $F_1$ but not in the other two species. Photosynthetic acclimation to elevated [$CO_2$] was observed in all species. The net photosynthetic rate measured at the growing [$CO_2$] (i.e. 380 ppm for ambient treatment and 600 ppm for elevated $CO_2$ treatment) was nevertheless greater in the seedlings of all species grown at elevated [$CO_2$]. The high [$CO_2$] partly compensated for the reduction of stem diameter growth of $F_1$ at high [$O_3$]; no similar trend was found in the other growth and photosynthetic parameters, or in the other species.

Dihydrosphingosine 1-phosphate: New Biomarker for Fumonisin B1 Toxicity

  • Lee, Yong-Moon;Yoo, Hwan-Soo;Oh, Sei-Kwan;Lee, Eun-Young;Kihara, Akio;Igarashi, Yasuyuki
    • Proceedings of the PSK Conference
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    • 2003.10b
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    • pp.69.1-69.1
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    • 2003
  • Fumonisins are a family of mycotoxins produced from Fusarium verticillioides. Most of fumonisin B1 (FB1) toxicities can be explained by its ability to alter sphingolipid metabolism by inhibiting ceramide synthase. At least, the elevation in dihydrosphingosine (DHS) mediates the earliest toxicity of FB1. Some tissues such as kidney and liver, may be most affected by FB1 because they shows high rates of de novo sphingolipid synthesis. Recent review on FB1 toxicity by A.H. Merrill Jr. et al. suggested the possible role of dihydrosphingosine 1-phosphate (dihydroS1P), which sometimes elevated in cell- or tissue specific manners. (omitted)

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Photochemistry of pharaonis phoborhodopsin and its interaction with the transducer

  • Kamo, Naoki;Shimono, Kazumi;Iwamoto, Masayuki;Sudo, Yuki;Yoshida, Hideaki
    • Journal of Photoscience
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    • v.9 no.2
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    • pp.102-105
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    • 2002
  • Phoborhodopsin (pR or sensory rhodopsin II, sRII; the absorption maximum of ∼ 500 nm) is a retinoid protein and works as a photoreceptor of the negative phototaxis of Halobacterium salinarum. pharaonis phoborhodopsin (ppR or pharaonis sensory rhodopsin II, psRII) is a corresponding protein of Natronobacterium pharaonis. These sensory proteins form a complex with a cognate transducer protein in the membrane, and this complex transmits the light-signal to the cytoplasm to evoke avoidance reaction from blue-green light. Recently, the functional expression in Escherichia coli membrane of ppR was achieved, which can afford a large amount of the protein and enables mutant studies to clarify the role of various amino acid residues. A truncated transducer which can bind to ppR is also expressed in Escherichia. coli membrane. In this article, we will review properties of ppR mainly using observations of our laboratory; which contains photochemistry (photocycle), light-driven proton uptake, release and transport, F -helix titling during photocycle and association of the transducer.

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$C_{x}F_{y}$ Polymer Film Deposition in rf and dc $C_{7}F_{16}$ Vapor Plasmas

  • Sakai, Y.;Akazawa, M.;Sakai, Yosuke;Sugawara, H.;Tabata, M.;Lungu, C.P.;Lungu, A.M.
    • Transactions on Electrical and Electronic Materials
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    • v.2 no.1
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    • pp.1-6
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    • 2001
  • $C_{x}F_{y}$ polymer film was deposited in rf and dc Fluorinert vapor ($C_{7}F_{16}$) plasmas. In the plasma phase, the spatial distribution of optical emission spectra and the temporal concentration of decomposed species were monitored, and kinetics of the $C_{7}F_{16}$ decomposition process was discussed. Deposition of $C_{x}F_{y}$ film has been tried on substrates of stainless steel, glass, molybdenum and silicon wafers at room temperature in the vapor pressures of 40 and 100 Pa. The films deposited in the rf plasma showed excellent electrical properties as an insulator for multi-layered interconnection of deep-submicron LSI, i.e. the low dielectric constant ∼2.0, the dielectric strength ∼2 MV/cm and the high deposition rate ∼100nm/min at 100W input power.

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VARIATIONS IN THE SOYA WARM CURRENT OBSERVED BY HF OCEAN RADAR, COASTAL TIDE GAUGES AND SATELLITE ALTIMETRY

  • Ebuchi, Naoto;Fukamachi, Yasushi;Ohshima, Kay I.;Shirasawa, Kunio;Wakatsuchi, Masaaki
    • Proceedings of the KSRS Conference
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    • v.1
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    • pp.17-20
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    • 2006
  • Three HF ocean radar stations were installed at the Soya/La Perouse Strait in the Sea of Okhotsk in order to monitor the Soya Warm Current. The frequency of the HF radar is 13.9 MHz, and the range and azimuth resolutions are 3 km and $5^{\circ}$, respectively. The radar covers a range of approximately 70 km from the coast. It is shown that the HF radars clearly capture seasonal and short-term variations of the Soya Warm Current. The velocity of the Soya Warm Current reaches its maximum, approximately 1 m $s^{-1}$, in summer, and weakens in winter. The velocity core is located 20 to 30 km from the coast, and its width is approximately 50 km. The surface transport by the Soya Warm Current shows a significant correlation with the sea level difference along the strait, as derived from coastal tide gauge records. The cross-current sea level difference, which is estimated from the sea level anomalies observed by the Jason-1 altimeter and a coastal tide gauge, also exhibits variation in concert with the surface transport and along-current sea level difference.

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