Publications by authors named "Izumi Serizawa"

The effect of temperature on photoluminescence (PL) due to theP→S(= 5/2, 7/2) transitions of Gdions was examined between 200 and 500 K for a sol-gel-derived silica-(Gd,Pr)POtransparent glass-ceramic phosphor with negligible concentration quenching under excitation into the 5d-4f transition of Prions at 220 nm. The intensity of the narrow-band ultraviolet B (UVB) PL at ∼313 nm associated with theP→Stransition slightly increased between 200 and 300 K, but was decreased to ∼86% and ∼62% of that at 300 K when temperature was raised to 400 and 500 K, respectively. The observed magnitude of the thermal quenching of the UVB PL intensity was agreed well with that recorded in a prototype narrow-band UVB lamp consisting of another silica-(Gd,Pr)POtransparent glass-ceramic window and a KrCl excimer lamp as a light source at 222 nm.

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Recently, the conversion of carbon dioxide (CO) into a useful resource and its byproducts by electrocatalytic reduction has been studied. It is well known that CO can be selectively reduced by gold, lead, etc. supported on conductive carbon.

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A simple water treatment system consisting of a deep UV light (λ = 222 nm) source, a mesoporous TiO/boron-doped diamond (BDD) photocatalyst, and a BDD electrode was prepared and used to decompose sulfamethoxazole (SMX) in an advanced oxidation process. The mesoporous TiO/BDD photocatalyst used with the electrochemical treatment promoted SMX decomposition, but the mesoporous TiO/BDD photocatalyst alone had a similar ability to decompose SMX as photolysis. Fragments produced through photocatalytic treatment were decomposed during the electrochemical treatment and fragments produced during the electrochemical treatment were decomposed during the photocatalytic treatment, so performing the electrochemical and photocatalytic treatments together effectively decomposed SMX and decrease the total organic carbon concentration to a trace.

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Boron-doped diamond (BDD) electrodes have a wide potential window and can produce ozone by water electrolysis at high voltage. Though ozone has strong oxidative power (standard oxidation potential: 2.07 V NHE), it cannot decompose certain types of recalcitrant organic matter completely.

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There is a need for highly efficient photocatalysts, particularly for water purification. In this study, we fabricated a mesoporous TiO₂ thin film on a boron-doped diamond (BDD) layer by a surfactant-assisted sol-gel method, in which self-assembled amphiphilic surfactant micelles were used as an organic template. Scanning electron microscopy revealed uniform mesopores, approximately 20 nm in diameter, that were hexagonally packed in the TiO₂ thin film.

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An enhanced vasoconstrictor activity of cutaneous arteries participates in the reduction of skin blood flow induced by cooling stimulation. Raynaud's phenomenon, which is characterized by intense cooling-induced constriction of cutaneous arteries, is more common in women during the period from menarche to menopause. We thus investigated the effect of 17β-estradiol (E2) on cooling-induced reduction of plantar skin blood flow (PSBF) in mouse in vivo.

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Materials fabricated with unsintered hydroxyapatite/poly-l-lactic acid (uHA/PLLA) exhibit biological activity and biocompatibility, but are also hydrophobic. This hydrophobicity limits the ability of cells or tissues to adhere to the surface of the material and thereby prevents the materials from exhibiting effective biological activity. In this study, we examined the effects of ultraviolet (UV) treatment on the hydrophobicity of uHA/PLLA.

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Competitive hydrogen evolution and multiple proton-coupled electron transfer reactions limit photoelectrochemical CO reduction in aqueous electrolyte. Here, oxygen-terminated lightly boron-doped diamond (BDD) thin films were synthesized as a semiconductor electron source to accelerate CO reduction. However, BDD alone could not stabilize the intermediates of CO reduction, yielding a negligible amount of reduction products.

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