Fumiki Takahashi

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1. A computational model accounting for motion detection in the fly was examined by comparing responses in motion-sensitive horizontal system (HS) and centrifugal horizontal (CH) cells in the fly's lobula plate with a computer simulation implemented on a motion detector of the correlation type, the Reichardt detector. First-order (linear) and second-order(More)
This paper reports on a rapid and sensitive method for the simultaneous determination of ascorbic acid (H(2)A), dehydroascorbic acid (DHA), and total vitamin C by electrochemiluminescence (ECL) using a thin-layer electrochemical cell. Significant ECL signals can be generated by the anodic oxidation of Ru(bpy)(3) (2+) in the presence of H(2)A or DHA in pH(More)
A microextraction technique based on ultrasonic emulsification and demulsification was developed for detecting pesticides at trace levels in environmental water samples. In this ultrasound-assisted microextraction (UAME), chloroform was emulsified with an aqueous sample solution containing trace fenitrothion (MEP) by ultrasonic irradiation (48 kHz) for 5(More)
In order to determine trace choline in human urine, a flow injection analysis (FIA) system has been developed by coupling an enzyme reactor with an electrochemiluminescence (ECL) detector. The enzyme reactor is prepared by covalently immobilizing choline oxidase (ChOx) onto the aminopropyl-controlled pore glass beads, which are then carefully packed into a(More)
The electrochemiluminescence (ECL) of tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)3(2+)) is studied in non-aqueous media using dehydroascorbic acid (DHA) as coreactant to validate the evidence for the mechanism of the ascorbic acid (H2A)/Ru(bpy)3(2+) ECL system in an aqueous media. DHA is electrochemically reduced around -1.2 V vs. Ag/Ag(+) in pure(More)
In this study, electrochemiluminescence (ECL) of Ru(bpy)(3)(2+) (bpy = 2,2'-bipyridyl) using ascorbic acid (H(2)A) as co-reactant was investigated in an aqueous solution. When H(2)A was co-existent in a Ru(bpy)(3)(2+)-containing buffer solution, ECL peaks were observed at a potential corresponding to the oxidation of Ru(bpy)(3)(2+), and the intensity was(More)
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