Publications by authors named "Shukichi Tanaka"

Background: The second demonstration experiment of supporting elderly people going out with the Choisoko system was conducted. The first study showed that for women, friends, shopping, convenience, and events are factors that have the potential to be effective motivational factors for encouraging these women to go out. On the other hand, these factors did not lead to any behavioral change in men.

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Biomimetic visual sensors utilizing bacteriorhodopsin (bR) were fabricated by using an inkjet method. The inkjet printer facilitated the jetting of the bR suspension, allowing for the deposition of bR films. The resulting inkjet-printed bR film exhibited time-differential photocurrent response characteristics similar to those of a dip-coated bR film.

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Maintaining a social environment that enables going out freely is important for older people and aids the prevention of frailty syndrome. However, losing a driver's license can increase the long-term care needs of older people. Therefore, outing support systems are important.

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Infrared spectroscopy was performed on ionic liquids (ILs) that had imidazolium cations with different alkyl chain lengths and various halogen or molecular anions with and without a small amount of water. The molar concentration normalized absorbance due to C-H vibrational modes in the range of 3000 to 3200 cm was nearly identical for ILs that had imidazolium cations with different alkyl chain lengths and the same anions. A close correlation was found between the red-shifted C-H vibrational modes, the chemical shift of C(2)-H proton, and the energy stabilization of the hydrogen-bonding interaction.

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We developed a new patterning method for bacteriorhodopsin (bR) thin films using UV light irradiation. The proton pump function of bR thin films can be deactivated with UV light irradiation. Inactivation of the proton pump function of bR is related to structural changes or photo-bleaching of the retinal in bR using UV light exposure, which was confirmed with absorption and Raman spectroscopy measurements.

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We fabricated a grating-structured electrode made of indium-doped zinc oxide (IZO) with a high refractive index (approximately 2) for a bacteriorhodopsin (bR) photocell. We investigated the photocurrent characteristics of the bR photocell and demonstrated that the photocurrent values from the bR/IZO electrode with the grating structure with a grating period of 340 nm were more than 3.5-4 times larger than those without the grating structure.

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In this study, we investigated the electrical transport properties of niobium titanium nitride (NbTiN) nanowire with four-terminal geometries to clarify the superconducting phase slip phenomena and superconducting-insulator transitions (SIT) for one-dimensional superconductors. We fabricated various nanowires with different widths and lengths from epitaxial NbTiN films using the electron beam lithography method. The temperature dependence of resistance R(T) below the superconducting transition temperature Tc was analyzed using thermal activation phase slip (TAPS) and quantum phase slip (QPS) theories.

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The terahertz- and infrared-frequency vibrational modes of various room-temperature imidazolium-based ionic liquids with molecular anions were examined extensively. We found that the molar-concentration-normalized absorption coefficient spectra in the low-wavenumber range for imidazolium cations with different alkyl-chain lengths were nearly identical for the same anion. Regarding the overall view of a wide range of imidazolium-based ionic liquids, we found that the reduced mass of the combination of an imidazolium-ring cation and the anion and the force constant play significant roles in determining the central frequency of the broad absorption band.

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The terahertz and infrared frequency vibration modes of room-temperature ionic liquids with imidazolium cations and halogen anions were extensively investigated. There is an intermolecular vibrational mode between the imidazolium ring of an imidazolium cation, a halogen atomic anion with a large absorption coefficient and a broad bandwidth in the low THz frequency region (13-130 cm), the intramolecular vibrational modes of the alkyl-chain part of an imidazolium cation with a relatively small absorption coefficient in the mid THz frequency region (130-500 cm), the intramolecular skeletal vibrational modes of an imidazolium ring affected by the interaction between the imidazolium ring, and a halogen anion with a relatively large absorption coefficient in a high THz frequency region (500-670 cm). Interesting spectroscopic features on the interaction between imidazolium cations and halogen anions was also obtained from spectroscopic studies at IR frequencies (550-3300 cm).

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Various three-dimensional structures have been created on a nanometer scale using the self-assembly of DNA molecules. However, ordinary DNA structures breakdown readily because of their flexibility. In addition, it is difficult to control them by inputs from environments.

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Metal-metal bonds are not essential for multiply bridging hydride ligands. A tetranuclear μ -hydride complex [(μ -H)Rh (PNNP) (CO) ] (PNNP=3,5-bis(diphenylphosphanylmethyl)pyrazolate), in which the quadruply bridging hydrido ligand holds the four isolated metal centers together to form a tetrahedral metal array, has been prepared and characterized by spectroscopic methods and single-crystal X-ray diffraction.

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