The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform

Junichi Sakai - One of the best experts on this subject based on the ideXlab platform.

  • improved fracture properties of ni ti superelastic alloy under sustained tensile load in Physiological Saline Solution containing hydrogen peroxide by hydrogen charging
    Journal of Alloys and Compounds, 2018
    Co-Authors: Takehiro Shimada, Kenichi Yokoyama, Junichi Sakai
    Abstract:

    Abstract We have attempted to improve the fracture properties of Ni-Ti superelastic alloy under a sustained tensile load in Physiological Saline Solution containing hydrogen peroxide by charging with a small amount of hydrogen, which causes negligible hydrogen embrittlement. For hydrogen charged in the parent phase, no pitting potential is observed in anodic polarization curves for the present test Solution; the time to fracture increases under an applied stress even in the elastic deformation region of the martensite phase. Upon aging after hydrogen charging, the pitting potential varies widely and the increase in the time to fracture slightly decreases. Hydrogen charging increases the time until a rapid shift of the corrosion potential in the less noble direction, corresponding to the breakdown of surface oxide films. The final fracture is mainly caused by overloading due to localized corrosion irrespective of hydrogen charging. For hydrogen charged in the martensite phase, i.e., the specimen not subjected to interactions between hydrogen and the stress-induced phase transformations, the time to fracture increases by more than that of the specimen subjected to the interactions. The present study indicates that a small amount of hydrogen charging is effective for inhibiting the localized corrosion of Ni-Ti superelastic alloy under applied stress in Physiological Saline Solution containing hydrogen peroxide, thereby improving the fracture properties. In addition, changes in the hydrogen states and/or defects induced by the interactions between hydrogen and phase transformations probably play an important role in improving the fracture properties.

  • improvements in fracture properties of ni ti superelastic alloy in Physiological Saline Solution containing hydrogen peroxide by surface modification
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009
    Co-Authors: Kenichi Yokoyama, Tokunori Kanemura, Junichi Sakai
    Abstract:

    Abstract The fracture properties of surface-modified Ni–Ti superelastic alloy are examined by a sustained tensile-loading test in Physiological Saline Solution containing hydrogen peroxide. The surface modification of the alloy is performed by chemical etching in 35 mass% nitric acid Solution at 60 °C for a long time (3 h). By modifying the surface of the specimen, many corrosion pits are formed and the surface roughness increases. When the surface-modified specimen is immersed in the test Solution without applied stress, corrosion occurs over the entire specimen and the amount of dissolved nickel ions increases. Nevertheless, under applied stress, the localized corrosion leading to the fracture is inhibited and the fracture mechanism changes, thereby increasing the time to fracture. The effects of the surface modification are confirmed even under applied stress above the critical stress for martensite transformation. The present study suggests that the effectiveness of the surface modification of Ni–Ti superelastic alloy should be investigated not only without applied stress but also under applied stress.

  • effects of acid type on corrosion and fracture behavior of ni ti superelastic alloy under sustained tensile load in Physiological Saline Solution containing hydrogen peroxide
    Corrosion Science, 2008
    Co-Authors: Tokunori Kanemura, Kenichi Yokoyama, Junichi Sakai
    Abstract:

    Abstract The effects of acid on the corrosion and fracture behavior of Ni–Ti superelastic alloy have been examined by sustained tensile-loading test in Physiological Saline Solution containing hydrogen peroxide. For immersion test without applied stress at the same Solution pH, although corrosion is enhanced markedly irrespective of the type of acid added, corrosion morphology depends on the type of acid added. The amount of dissolved nickel ions increases in the order of the Solutions with lactic acid > phosphoric acid > acetic acid. The amount of dissolved nickel ions increases with decreasing Solution pH. In contrast, under applied stress, the time to fracture in the Solution with phosphoric acid becomes longer than that in the Solution without acid, although the time to fracture does not increase in the Solution with acetic acid or lactic acid. The time to fracture is only slightly affected by Solution pH for the same type of acid added. Fractographic features change in the Solution with phosphoric acid. The present study suggests that the fracture behavior of Ni–Ti superelastic alloy in Physiological Saline Solution containing hydrogen peroxide depends on acid type rather than on Solution pH; the fracture behavior is not necessarily consistent with the corrosion behavior in the case without applied stress.

  • fracture of ni ti superelastic alloy under sustained tensile load in Physiological Saline Solution containing hydrogen peroxide
    Journal of Biomedical Materials Research Part A, 2007
    Co-Authors: Kenichi Yokoyama, Toshio Ogawa, Atsushi Fujita, Kenzo Asaoka, Junichi Sakai
    Abstract:

    The fracture of Ni-Ti superelastic alloy has been investigated by a sustained tensile-loading test in Physiological Saline Solution containing hydrogen peroxide (0.15M NaCl + 0.3M H2O2). The fracture always occurs when the applied stress exceeds the critical stress for martensite transformation. In contrast, under a low applied stress, the fracture does not always occur within 1000 h. The fracture is probably mainly caused by localized corrosion associated with the preferential disSolution of nickel ions. In 0.3M H2O2 Solution without NaCl, the fracture does not occur even under a high applied stress. The results of the present study imply that one reason for the fracture of the Ni-Ti superelastic alloy in vivo is localized corrosion due to the synergistic effects of hydrogen peroxide and sodium chloride under applied stress. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007

Kiyonori Yoshii - One of the best experts on this subject based on the ideXlab platform.

  • a method for in situ tight seal recordings from single taste bud cells of mice
    Journal of Neuroscience Methods, 1998
    Co-Authors: Hidemasa Furue, Kiyonori Yoshii
    Abstract:

    In order to investigate taste transduction mechanisms, we developed a method to irrigate the receptor and basolateral membranes of mouse taste bud cells with different Solutions under tight-seal recording conditions. A peeled tongue epithelium with taste bud cells was mounted on a recording platform designed to separate irrigating Solutions for each membrane. The mucosal surface (receptor membrane side) of the peeled epithelium facing an inner chamber was always irrigated with deionized water or stimulating Solutions, and the serosal surface (basolateral membrane side) was irrigated with a Physiological Saline Solution. A recording electrode was placed on the basolateral membrane of a taste bud cell under an upright-microscope with a x 40-water-immersed objective. Investigated taste bud cells generated action potentials, and 1 M glucose, 200 mM NaCl, and 10 mM quinine elicited inward current. Irrigation with deionized water for more than 1 h had no effect. The resistance of the peeled tongue epithelium was 1570 +/- 343 omega cm2. These results show that the peeled tongue epithelium protects basolateral membranes from deionized water or stimulating Solutions as the tongue epithelium does in situ and that this method is suitable to investigate the role of each membrane in taste transduction.

  • in situ tight seal recordings of taste substance elicited action currents and voltage gated ba currents from single taste bud cells in the peeled epithelium of mouse tongue
    Brain Research, 1997
    Co-Authors: Hidemasa Furue, Kiyonori Yoshii
    Abstract:

    We investigated the taste responses of single taste-bud cells (TBCs) in mice by applying stimuli only on receptor membranes acclimated to deionized water under tight-seal cell-attached voltage-clamp conditions, while their basolateral membranes were irrigated with a Physiological Saline Solution. For this irrigation, we developed a new method: a peeled-tongue epithelium with TBCs mounted on a recording chamber where the peeled epithelium separated the irrigating Solutions for each membrane as it separated in situ. Although no quinine-elicited action potentials had been reported, TBCs elicited a long-lasting train of biphasic currents derived from the action potentials in response to 10 mM quinine, in addition to responses to 10 mM HCl, or 200 mM NaCl dissolved in deionized water. These results indicate that quinine as well as HCl and NaCl depolarizes TBCs and generate action potentials. Under whole-cell recording conditions, TBCs generated action potentials, and voltage-gated currents such as LVA and HVA Ca currents, TTX-sensitive Na currents, and TEA/4-AP-sensitive K currents on depolarization. These voltage-gated channels were shown to exist predominantly on the basolateral membranes. We discussed the receptor mechanisms and the role of taste substance-elicited action potentials.

Kenichi Yokoyama - One of the best experts on this subject based on the ideXlab platform.

  • improved fracture properties of ni ti superelastic alloy under sustained tensile load in Physiological Saline Solution containing hydrogen peroxide by hydrogen charging
    Journal of Alloys and Compounds, 2018
    Co-Authors: Takehiro Shimada, Kenichi Yokoyama, Junichi Sakai
    Abstract:

    Abstract We have attempted to improve the fracture properties of Ni-Ti superelastic alloy under a sustained tensile load in Physiological Saline Solution containing hydrogen peroxide by charging with a small amount of hydrogen, which causes negligible hydrogen embrittlement. For hydrogen charged in the parent phase, no pitting potential is observed in anodic polarization curves for the present test Solution; the time to fracture increases under an applied stress even in the elastic deformation region of the martensite phase. Upon aging after hydrogen charging, the pitting potential varies widely and the increase in the time to fracture slightly decreases. Hydrogen charging increases the time until a rapid shift of the corrosion potential in the less noble direction, corresponding to the breakdown of surface oxide films. The final fracture is mainly caused by overloading due to localized corrosion irrespective of hydrogen charging. For hydrogen charged in the martensite phase, i.e., the specimen not subjected to interactions between hydrogen and the stress-induced phase transformations, the time to fracture increases by more than that of the specimen subjected to the interactions. The present study indicates that a small amount of hydrogen charging is effective for inhibiting the localized corrosion of Ni-Ti superelastic alloy under applied stress in Physiological Saline Solution containing hydrogen peroxide, thereby improving the fracture properties. In addition, changes in the hydrogen states and/or defects induced by the interactions between hydrogen and phase transformations probably play an important role in improving the fracture properties.

  • improvements in fracture properties of ni ti superelastic alloy in Physiological Saline Solution containing hydrogen peroxide by surface modification
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009
    Co-Authors: Kenichi Yokoyama, Tokunori Kanemura, Junichi Sakai
    Abstract:

    Abstract The fracture properties of surface-modified Ni–Ti superelastic alloy are examined by a sustained tensile-loading test in Physiological Saline Solution containing hydrogen peroxide. The surface modification of the alloy is performed by chemical etching in 35 mass% nitric acid Solution at 60 °C for a long time (3 h). By modifying the surface of the specimen, many corrosion pits are formed and the surface roughness increases. When the surface-modified specimen is immersed in the test Solution without applied stress, corrosion occurs over the entire specimen and the amount of dissolved nickel ions increases. Nevertheless, under applied stress, the localized corrosion leading to the fracture is inhibited and the fracture mechanism changes, thereby increasing the time to fracture. The effects of the surface modification are confirmed even under applied stress above the critical stress for martensite transformation. The present study suggests that the effectiveness of the surface modification of Ni–Ti superelastic alloy should be investigated not only without applied stress but also under applied stress.

  • effects of acid type on corrosion and fracture behavior of ni ti superelastic alloy under sustained tensile load in Physiological Saline Solution containing hydrogen peroxide
    Corrosion Science, 2008
    Co-Authors: Tokunori Kanemura, Kenichi Yokoyama, Junichi Sakai
    Abstract:

    Abstract The effects of acid on the corrosion and fracture behavior of Ni–Ti superelastic alloy have been examined by sustained tensile-loading test in Physiological Saline Solution containing hydrogen peroxide. For immersion test without applied stress at the same Solution pH, although corrosion is enhanced markedly irrespective of the type of acid added, corrosion morphology depends on the type of acid added. The amount of dissolved nickel ions increases in the order of the Solutions with lactic acid > phosphoric acid > acetic acid. The amount of dissolved nickel ions increases with decreasing Solution pH. In contrast, under applied stress, the time to fracture in the Solution with phosphoric acid becomes longer than that in the Solution without acid, although the time to fracture does not increase in the Solution with acetic acid or lactic acid. The time to fracture is only slightly affected by Solution pH for the same type of acid added. Fractographic features change in the Solution with phosphoric acid. The present study suggests that the fracture behavior of Ni–Ti superelastic alloy in Physiological Saline Solution containing hydrogen peroxide depends on acid type rather than on Solution pH; the fracture behavior is not necessarily consistent with the corrosion behavior in the case without applied stress.

  • fracture of ni ti superelastic alloy under sustained tensile load in Physiological Saline Solution containing hydrogen peroxide
    Journal of Biomedical Materials Research Part A, 2007
    Co-Authors: Kenichi Yokoyama, Toshio Ogawa, Atsushi Fujita, Kenzo Asaoka, Junichi Sakai
    Abstract:

    The fracture of Ni-Ti superelastic alloy has been investigated by a sustained tensile-loading test in Physiological Saline Solution containing hydrogen peroxide (0.15M NaCl + 0.3M H2O2). The fracture always occurs when the applied stress exceeds the critical stress for martensite transformation. In contrast, under a low applied stress, the fracture does not always occur within 1000 h. The fracture is probably mainly caused by localized corrosion associated with the preferential disSolution of nickel ions. In 0.3M H2O2 Solution without NaCl, the fracture does not occur even under a high applied stress. The results of the present study imply that one reason for the fracture of the Ni-Ti superelastic alloy in vivo is localized corrosion due to the synergistic effects of hydrogen peroxide and sodium chloride under applied stress. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007

Hidemasa Furue - One of the best experts on this subject based on the ideXlab platform.

  • a method for in situ tight seal recordings from single taste bud cells of mice
    Journal of Neuroscience Methods, 1998
    Co-Authors: Hidemasa Furue, Kiyonori Yoshii
    Abstract:

    In order to investigate taste transduction mechanisms, we developed a method to irrigate the receptor and basolateral membranes of mouse taste bud cells with different Solutions under tight-seal recording conditions. A peeled tongue epithelium with taste bud cells was mounted on a recording platform designed to separate irrigating Solutions for each membrane. The mucosal surface (receptor membrane side) of the peeled epithelium facing an inner chamber was always irrigated with deionized water or stimulating Solutions, and the serosal surface (basolateral membrane side) was irrigated with a Physiological Saline Solution. A recording electrode was placed on the basolateral membrane of a taste bud cell under an upright-microscope with a x 40-water-immersed objective. Investigated taste bud cells generated action potentials, and 1 M glucose, 200 mM NaCl, and 10 mM quinine elicited inward current. Irrigation with deionized water for more than 1 h had no effect. The resistance of the peeled tongue epithelium was 1570 +/- 343 omega cm2. These results show that the peeled tongue epithelium protects basolateral membranes from deionized water or stimulating Solutions as the tongue epithelium does in situ and that this method is suitable to investigate the role of each membrane in taste transduction.

  • in situ tight seal recordings of taste substance elicited action currents and voltage gated ba currents from single taste bud cells in the peeled epithelium of mouse tongue
    Brain Research, 1997
    Co-Authors: Hidemasa Furue, Kiyonori Yoshii
    Abstract:

    We investigated the taste responses of single taste-bud cells (TBCs) in mice by applying stimuli only on receptor membranes acclimated to deionized water under tight-seal cell-attached voltage-clamp conditions, while their basolateral membranes were irrigated with a Physiological Saline Solution. For this irrigation, we developed a new method: a peeled-tongue epithelium with TBCs mounted on a recording chamber where the peeled epithelium separated the irrigating Solutions for each membrane as it separated in situ. Although no quinine-elicited action potentials had been reported, TBCs elicited a long-lasting train of biphasic currents derived from the action potentials in response to 10 mM quinine, in addition to responses to 10 mM HCl, or 200 mM NaCl dissolved in deionized water. These results indicate that quinine as well as HCl and NaCl depolarizes TBCs and generate action potentials. Under whole-cell recording conditions, TBCs generated action potentials, and voltage-gated currents such as LVA and HVA Ca currents, TTX-sensitive Na currents, and TEA/4-AP-sensitive K currents on depolarization. These voltage-gated channels were shown to exist predominantly on the basolateral membranes. We discussed the receptor mechanisms and the role of taste substance-elicited action potentials.

Tokunori Kanemura - One of the best experts on this subject based on the ideXlab platform.

  • improvements in fracture properties of ni ti superelastic alloy in Physiological Saline Solution containing hydrogen peroxide by surface modification
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009
    Co-Authors: Kenichi Yokoyama, Tokunori Kanemura, Junichi Sakai
    Abstract:

    Abstract The fracture properties of surface-modified Ni–Ti superelastic alloy are examined by a sustained tensile-loading test in Physiological Saline Solution containing hydrogen peroxide. The surface modification of the alloy is performed by chemical etching in 35 mass% nitric acid Solution at 60 °C for a long time (3 h). By modifying the surface of the specimen, many corrosion pits are formed and the surface roughness increases. When the surface-modified specimen is immersed in the test Solution without applied stress, corrosion occurs over the entire specimen and the amount of dissolved nickel ions increases. Nevertheless, under applied stress, the localized corrosion leading to the fracture is inhibited and the fracture mechanism changes, thereby increasing the time to fracture. The effects of the surface modification are confirmed even under applied stress above the critical stress for martensite transformation. The present study suggests that the effectiveness of the surface modification of Ni–Ti superelastic alloy should be investigated not only without applied stress but also under applied stress.

  • effects of acid type on corrosion and fracture behavior of ni ti superelastic alloy under sustained tensile load in Physiological Saline Solution containing hydrogen peroxide
    Corrosion Science, 2008
    Co-Authors: Tokunori Kanemura, Kenichi Yokoyama, Junichi Sakai
    Abstract:

    Abstract The effects of acid on the corrosion and fracture behavior of Ni–Ti superelastic alloy have been examined by sustained tensile-loading test in Physiological Saline Solution containing hydrogen peroxide. For immersion test without applied stress at the same Solution pH, although corrosion is enhanced markedly irrespective of the type of acid added, corrosion morphology depends on the type of acid added. The amount of dissolved nickel ions increases in the order of the Solutions with lactic acid > phosphoric acid > acetic acid. The amount of dissolved nickel ions increases with decreasing Solution pH. In contrast, under applied stress, the time to fracture in the Solution with phosphoric acid becomes longer than that in the Solution without acid, although the time to fracture does not increase in the Solution with acetic acid or lactic acid. The time to fracture is only slightly affected by Solution pH for the same type of acid added. Fractographic features change in the Solution with phosphoric acid. The present study suggests that the fracture behavior of Ni–Ti superelastic alloy in Physiological Saline Solution containing hydrogen peroxide depends on acid type rather than on Solution pH; the fracture behavior is not necessarily consistent with the corrosion behavior in the case without applied stress.