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151 results on '"Kamijo, Toshio"'

5. Highly sensitive glucose electrochemical sensor using sugar‐lectin interactions.

Author

Sugiyama, Kyoko, Sato, Fumiya, Komatsu, Sachiko, Kamijo, Toshio, Yoshida, Kentaro, Kawabe, Yusuke, Nishikawa, Hiromi, Fujimura, Tsutomu, Takahashi, Yasufumi, and Sato, Katsuhiko

Subjects
GLUCOSE oxidase, ELECTROCHEMICAL sensors, SERUM albumin, THIN films, PERMEABILITY
Abstract

In this study, glucose oxidase (GOx) was immobilized on the electrode surface by layer‐by‐layer and gel membrane technique and characterized the GOx immobilized film morphology, H2O2 permeability, and glucose response. Concanavalin A (Con A)‐GOx multilayer electrodes showed higher glucose‐related current response than GOx‐bovine serum albumin gel membrane‐coated electrode, a common modification method. The thin thickness of the Con A/GOx multilayer film efficiently catalyzed the enzymatic reaction, and H2O2 was produced near the electrode surface, resulting in an immediate electrode response. [ABSTRACT FROM AUTHOR]

Published
2024
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7. Measurement of a Phase of a Radio Wave Reflected from Rock Salt and Ice Irradiated by an Electron Beam for Detection of Ultra-High-Energy Neutrinos

Author

Chiba, Masami, Kamijo, Toshio, Tanikawa, Takahiro, Yano, Hiroyuki, Yabuki, Fumiaki, Yasuda, Osamu, Chikashige, Yuichi, Kon, Tadashi, Shimizu, Yutaka, Watanabe, Souichirou, Utsumi, Michiaki, and Fujii, Masatoshi

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Physics - Instrumentation and Detectors
Abstract

We have found a radio-wave-reflection effect in rock salt for the detection of ultra-high energy neutrinos which are expected to be generated in Greisen, Zatsepin, and Kuzmin (GZK) processes in the universe. When an UHE neutrino interacts with rock salt or ice as a detection medium, a shower is generated. That shower is formed by hadronic and electromagnetic avalanche processes. The energy of the UHE neutrino shower converts to thermal energy through ionization processes. Consequently, the temperature rises along the shower produced by the UHE neutrino. The refractive index of the medium rises with temperature. The irregularity of the refractive index in the medium leads to a reflection of radio waves. This reflection effect combined with the long attenuation length of radio waves in rock salt and ice would yield a new method to detect UHE neutrinos. We measured the phase of the reflected radio wave under irradiation with an electron beam on ice and rock salt powder. The measured phase showed excellent consistence with the power reflection fraction which was measured directly. A model taking into account the temperature change explained the phase and the amplitude of the reflected wave. Therefore the reflection mechanism was confirmed. The power reflection fraction was compared with that calculated with the Fresnel equations, the ratio between the measured result and that obtained with the Fresnel equations in ice was larger than that of rock salt., Comment: 6 Pages, 5th International Workshop on Acoustic and Radio EeV Neutrino Detection Activities

Published
2013
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9. Reflection of microwave from energy deposit by X-ray irradiation in rock salt: Implication of an ultra high energy salt neutrino detector to act like a radio bubble chamber

Author

Chiba, Masami, Arakawa, Yoko, Kamijo, Toshio, Nakamura, Shunsuke, Shibasaki, Yuji, Takayama, Yasuhiro, Watanabe, Yusuke, Yabuki, Fumiaki, Yasuda, Osamu, Amano, Akio, Chikashige, Yuichi, Ibe, Keisuke, Kon, Tadashi, Ninomiya, Sosuke, Shimizu, Yutaka, Takeoka, Yoshito, Taniuchi, Yasuyuki, Utsumi, Michiaki, and Fujii, Masatoshi

Subjects
Astrophysics
Abstract

Existence of GZK neutrinos (ultra high energy neutrinos) have been justified although the flux is very low. A new method is desired to use a huge mass of a detector medium to detect them. A fundamental study of radar method was carried out to measure microwave reflection from electromagnetic energy deposit by X-ray irradiation in a small rock salt sample. The reflection rate of 1x10^-6 was found at the energy deposit of 1x10^19 eV which was proportional to square of the X-ray intensity suggesting the effect to be coherent scattering. The decay time of the reflection was several seconds. This effect implies a large scale natural rock salt formation could be utilized like a bubble chamber irradiated by radio wave instead of visible light to detect GZK neutrinos., Comment: Submitted for the SUSY07 proceedings, 4 pages, LaTeX, 3 eps figures

Published
2007

11. Vancomycin sensing using a phenylboronic acid‐modified nanopore pipette.

Author

Sato, Fumiya, Nakano, Haruka, Kamijo, Toshio, Watanabe, Kazuhiro, Fujimura, Tsutomu, Takahashi, Yasufumi, and Sato, Katsuhiko

Subjects
VANCOMYCIN, PIPETTES, DRUG monitoring
Abstract

Nanopore sensing measures the changes in charge and physical state around the nanopores as changes in ionic current. In this study, we performed vancomycin (VCM) sensing with nanopores modified via Au−S bonds with dithiobis(4‐butyrylamino‐m‐phenylboronic acid) (DTBA‐PBA), a derivative of phenylboronic acid (PBA) bearing a thiol. First, we modified a 3‐mm‐diameter Au electrode with a DTBA‐PBA self‐assembled monolayer (SAM) to confirm the VCM response of the PBA interface by cyclic voltammetry. DTBA‐PBA was then immobilized in the same manner on a nanopore pipette coated with an Au layer. We measured the VCM concentration from the change in ion current using the nanopore pipette. A VCM concentration‐dependent ionic current response was observed in the range of 0.01–1 mM. Many kinds of pharmaceuticals can bind to PBA; therefore, this method could be used for quick, easy, in situ quantification of not only VCM but also other pharmaceuticals with serious side effects. [ABSTRACT FROM AUTHOR]

Published
2023
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18. Development of Low-Friction Ion Gels for Industrial Applications

Author

Kamijo, Toshio, Sato, Takaya, Morinaga, Takashi, and Arafune, Hiroyuki

Subjects
Science / Chemistry
Abstract

Friction reduction is imperative for improving the service life and energy efficiency of mechanical systems. Ion gels using ionic liquids (ILs) as swelling agents are expected to be stable gel lubricants owing to the high thermal stability and negligible volatility of ILs; they can maintain their swollen state even under harsh conditions. Therefore, we investigated two types of ion gels: an IL-substituted double-network gel (DN ion S-gel), in which the water in the DN hydrogel is replaced by the IL 3-ethyl-1-methyl-imidazolium ethylsulfate; and a DN ion gel containing N,N-diethyl-N-(2-methoxyethyl)-N-methyl-ammonium bis(trifluoromethylsulfonyl)imide (DEME-TFSI), where one of the polymer backbones is a network of poly(N,N-diethyl-N-(2-methacryloylethyl)-N-methylammonium bis(trifluoromethylsulfonyl)imide), an IL-type polymer based on our previous synthetic study of IL polymer technology. The DN ion S-gel and DN ion gel achieved compression strengths of 25 and 30 MPa, respectively, and were thermally stable until 196°C and 335°C (10% weight-loss temperature), respectively. The coefficient of friction remained stable and low (0.02) after repeated measurements under harsh conditions (high temperature or vacuum conditions), affirming the durability of the DN ion gel.

Published
2022

24. Adsorption and Release of Rose Bengal on Layer-by-Layer Films of Poly(Vinyl Alcohol) and Poly(Amidoamine) Dendrimers Bearing 4-Carboxyphenylboronic Acid

Author

Yoshida, Kentaro, primary, Yamaguchi, Akane, additional, Midorikawa, Hiroki, additional, Kamijo, Toshio, additional, Ono, Tetsuya, additional, Dairaku, Takenori, additional, Sato, Takaya, additional, Fujimura, Tsutomu, additional, Kashiwagi, Yoshitomo, additional, and Sato, Katsuhiko, additional

Published
2020
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26. Polymer Brush Made from Ionic Liquid and Its Anti-Biofilm Formation Behaviors By Environmental Biota in a Flow-Type Laboratory Biofilm Reactor

Author

Kanematsu, Hideyuki, primary, Oizumi, Atsuya, additional, Sato, Takaya, additional, Sato, Ryo, additional, Kamijo, Toshio, additional, Honma, Saika, additional, Hirai, Nobumitsu, additional, Kogo, Takeshi, additional, Ogawa, Akiko, additional, Tsunashima, Katsuhiko, additional, and Barry, Dana M., additional

Published
2020
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31. Biofilm Formation of a Polymer Brush Coating with Ionic Liquids Compared to a Polymer Brush Coating with a Non-Ionic Liquid

Author

Kanematsu, Hideyuki, primary, Oizumi, Atsuya, additional, Sato, Takaya, additional, Kamijo, Toshio, additional, Honma, Saika, additional, Barry, Dana, additional, Hirai, Nobumitsu, additional, Ogawa, Akiko, additional, Kogo, Takeshi, additional, Kuroda, Daisuke, additional, Sano, Katsuhiko, additional, Tsunashima, Katsuhiko, additional, Lee, Seung-Hyo, additional, and Lee, Myeong-Hoon, additional

Published
2018
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37. Solvatio dynamics of coumarin 153 in alcohols confined in silica nanochannels

Author

Kamijo, Toshio, Yamaguchi, Akira, Suzuki, Shintaro, Teramae, Norio, Itoh, Tetsuji, and Ikeda, Takuji

Subjects
Alcohols -- Chemical properties, Coumarins -- Chemical properties, Coumarins -- Structure, Fluorescence spectroscopy -- Usage, Silica -- Structure, Silica -- Chemical properties, Solvation -- Analysis, Chemicals, plastics and rubber industries
Published
2008

38. Radar Chamber for Detection of UHE Neutrinos

Author

Chiba, Masami, primary, Kamijo, Toshio, additional, Yano, Hiroyuki, additional, Yabuki, Fumiaki, additional, Chikashige, Yuichi, additional, Inohara, Yusuke, additional, Kon, Tadashi, additional, Ogushi, Yuta, additional, Shimizu, Yutaka, additional, Utsum, Michiaki, additional, and Fujii, Masatoshi, additional

Published
2017
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41. Synthesis of Monodisperse Silica Particles Grafted with Concentrated Ionic Liquid-Type Polymer Brushes by Surface-Initiated Atom Transfer Radical Polymerization for Use as a Solid State Polymer Electrolyte

Author

00217308, Morinaga, Takashi, Honma, Saika, Ishizuka, Takeo, Kamijo, Toshio, Sato, Takaya, Tsujii, Yoshinobu, 00217308, Morinaga, Takashi, Honma, Saika, Ishizuka, Takeo, Kamijo, Toshio, Sato, Takaya, and Tsujii, Yoshinobu

Abstract

A polymerizable ionic liquid, N, N-diethyl-N-(2-methacryloylethyl)-N-methylammonium bis(trifluoromethylsulfonyl)imide (DEMM-TFSI), was polymerized via copper-mediated atom transfer radical polymerization (ATRP). The polymerization proceeded in a living manner producing well-defined poly(DEMM-TFSI) of target molecular weight up to about 400 K (including a polycation and an counter anion). The accurate molecular weight as determined by a GPC analysis combined with a light scattering measurement, and the molecular weight values obtained exhibited good agreement with the theoretical values calculated from the initial molar ratio of DEMM-TFSI and the monomer conversion. Surface-initiated ATRP on the surface of monodisperse silica particles (SiPs) with various diameters was successfully performed, producing SiPs grafted with well-defined poly(DEMM-TFSI) with a graft density as high as 0.15 chains/nm2. Since the composite film made from the silica-particle-decorated polymer brush and ionic liquid shows a relatively high ionic conductivity, we have evaluated the relationship between the grafted brush chain length and the ionic conductivity.

Published
2016

43. Comparison of NAD with NADP‐dependent Glutamate Dehydrogenase, and CNT with rGO‐modified Electrodes, for the Construction of Glutamate Sensors.

Author

Kamijo, Toshio, Sato, Takaya, Sato, Katsuhiko, and Takahashi, Shigehiro

Subjects
*GLUTAMIC acid, *ELECTRODES, *ENZYMES, *ELECTROCHEMICAL analysis, *OXIDATION
Abstract

Glutamate sensors were prepared using nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP)‐dependent glutamate dehydrogenase (GDH). Glutamate was determined from the anodic oxidation current of NADH and NADPH generated by the enzymatic reaction of GDH. These two types of GDH enzymes were deposited separately on carbon nanotube (CNT) and reduced graphene oxide (rGO)‐modified glassy carbon electrodes, in which CNT and rGO were used to improve the oxidation capacity of the electrodes. An anodic peak current in response to 1 mM glutamate of glutamate sensors comprising each of these four combinations were compared under the same conditions. The glutamate response was the highest when NAD‐dependent GDH was deposited on the rGO‐modified electrode. [ABSTRACT FROM AUTHOR]

Published
2018
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