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Reaction rate constants of (−)-epigallocatechin gallate (EGCG) and (+)-catechin with the hydroxyl radical (·OH) were measured using the rapid flow ESR method. The rate constant of EGCG was larger twice than that of the pyrogallol or gallic acid, they are the model compounds of the B ring of EGCG. It was explained by the quantum-chemical calculation of the bond dissociation energy (BDE) of the phenolic hydroxyl group (ϕ-OH) and the spin densities of EGCG radical. The energy of the EGCG radical was lowered by the hydrogen bonding between the radical part on the B ring and the hydroxyl group on the gallate group, leading to the lowering of BDE. Linear relationship between the relative activation energy and BDE of all the polyphenols measured was observed (Evans-Polanyi equation), showing that the reaction with ·OH occurs in the same manner. [ABSTRACT FROM AUTHOR]

The D2 + was irradiated into SiC up to the saturation and thereafter He+ irradiation was performed to elucidate interaction mechanism between hydrogen isotope retained in SiC and irradiated energetic He+ by means of X-ray photoelectron spectroscopy (XPS) and thermal desorption spectroscopy (TDS). It was found that D was trapped by both of Si and C by D2 + irradiation and only D bound to Si interacted with irradiated He+ in the initial He+ irradiation. By heating after the irradiation experiments, most of SiC structure was recovered at the temperature above 1000 K. However, some free C was migrated toward the surface and aggregated on the surface of SiC. This fact indicates that the C impurity would contaminate the plasma and/or the tritium breeding materials, which is thought to be contacted with the SiC inserts. [ABSTRACT FROM AUTHOR]2 + and He+ irradiation. By heating after the irradiation experiments, most of SiC structure was recovered at the temperature above 1000 K. However, some free C was migrated toward the surface and aggregated on the surface of SiC. This fact indicates that the C impurity would contaminate the plasma and/or the tritium breeding materials, which is thought to be contacted with the SiC inserts. [ABSTRACT FROM AUTHOR]

The annihilation behavior of irradiation defects induced in neutron-irradiated Li2TiO3 and Li2ZrO3 were investigated with the tritium release behavior. It was revealed that the common characteristics in both samples were that the annihilation process of irradiation defects consisted of two first-order processes and E’-center could act as tritium trapping site, and otherwise was the way how the E’-center annihilated. The difference was suggested to attribute to the mobility of M as M4+ (or M3+, etc.). [ABSTRACT FROM AUTHOR]

Inhibiting effect of four tea catechins, (−)-epicatechin (EC), (−)-epicatechin gallate (ECG), (−)-epigallocatechin (EGC), (−)-epigallocatechin gallate (EGCG), on the lipid peroxidation induced by β-ray in tritiated water was examined using a spin probe method. 16-Doxylstearic acid (16NS) was incorporated into the liposome prepared from egg yolk phosphatidylcholine and the rate of the decrease of ESR intensity of 16NS was used as a measure of the inhibiting effect. In the low concentration region below 10−5M, catechins showed their inhibitions on the lipid peroxidation according to the order of ECG>EGCG>EC>EGC. This result was explained by a model that the initiator of the peroxidation is the hydroxyl radical (·OH) and the catechins adsorbed on the lipid membrane surface acting as scavengers of ·OH. In the high concentration range, however, the effect was diverse and it decreased with the increase of it in the case of EGCG. EGCG in this range was considered to enter into the interior of the membrane and break the structure, which causes the decrease of 16NS. Observation with transmission electron microscope (TEM) revealed that the size of the liposome became larger with the increasing concentration of EGCG and finally it was broken into fragments, showing that EGCG broadened the area of the liposome as expected from the result of ESR. [ABSTRACT FROM AUTHOR]

The effects of irradiation damages induced by neutron irradiation on tritium release processes were studied in Li4SiO4. It was shown that the thermal annealing process of the damages consisted of two processes of a fast and a slow process. The activation energies were determined to be 0.21 eV and 1.1 eV, respectively. From the experimental results, it was suggested that the migration of tritium and displaced oxygen into the damages plays an important role in both thermal annealing processes. [ABSTRACT FROM AUTHOR]

The recombination reactions of thermal H and T atoms, H+T→HT and T+T→T2, have been investigated using radiochemical methods at 1.4-2.5 K in a mixture of 3He-4He. The reactive species were produced via 3He(n,p)T by neutron irradiation at the upgraded Japan Research Reactor No. 3 (JRR-3M). Nonstatistical formation of ortho-T2 was observed over the entire range of 3He atomic fraction at 1.4-2.5 K. The relative yield of T2 decreased with an increase in superfluid component, which is a second liquid phase observed only in liquid helium, at 1.6 K. [ABSTRACT FROM AUTHOR]

The annihilation behavior of irradiation defects induced in neutron-irradiated Li2TiO3 and Li2ZrO3 were investigated with the tritium release behavior. It was revealed that the common characteristics in both samples were that the annihilation process of irradiation defects consisted of two first-order processes and E’-center could act as tritium trapping site, and otherwise was the way how the E’-center annihilated. The difference was suggested to attribute to the mobility of M as M4+ (or M3+, etc.). [ABSTRACT FROM AUTHOR]

The effects of irradiation damages induced by neutron irradiation on tritium release processes were studied in Li4SiO4. It was shown that the thermal annealing process of the damages consisted of two processes of a fast and a slow process. The activation energies were determined to be 0.21 eV and 1.1 eV, respectively. From the experimental results, it was suggested that the migration of tritium and displaced oxygen into the damages plays an important role in both thermal annealing processes. [ABSTRACT FROM AUTHOR]