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To investigate the relationship between fenofibrate (FF) and oxidative stress, enzymatic, histopathological, and molecular biological analyses were performed in the liver of male F344 rats fed 2 doses of FF (Experiment 1; 0 and 6000 ppm) for 3 weeks and 3 doses (Experiment 2; 0, 3000, and 6000 ppm) for 9 weeks. FF treatment increased the activity of enzymes such as carnitine acetyltransferase, carnitine palmitoyltransferase, fatty acyl-CoA oxidizing system, and catalase in the liver. However, it decreased those of superoxide dismutase in the liver in both experiments. Increased 8-hydroxy-2'-deoxyguanosine levels in liver DNA and lipofuscin accumulation were observed in the treated rats of Experiment 2. In vitro measurement of reactive oxygen species (ROS) in rat liver microsomes revealed a dose-dependent increase due to FF treatment. Microarray (only Experiment 1) or real-time reverse transcription-polymerase chain reaction analyses revealed that the expression levels of metabolism and DNA repair-related genes such as Aco, Cyp4a1, Cat, Yc2, Gpx2, Apex1, Xrcc5, Mgmt, Mlh1, Gadd45a, and Nbn were increased in FF-treated rats. These results provide evidence of a direct or indirect relationship between oxidative stress and FF treatment. In addition, increases in the expression levels of cell cycle-related genes such as Chek1, Cdc25a, and Ccdn1; increases in the expression levels of cell proliferation-related genes such as Hdgfrp3 and Vegfb; and fluctuations in the expression levels of apoptosis-related genes such as Casp11 and Trp53inp1 were observed in these rats. This suggests that cell proliferation induction, apoptosis suppression, and DNA damage due to oxidative stresses are probably involved in the mechanism of hepatocarcinogenesis due to FF in rats.

A slurry method was used to determine the dielectric permittivity (ɛr) of BaTiO3 powders with different characteristics, such as tetragonality (c/a ratio), density, particle size, and specific surface area. The ɛr of powders highly depended on their characteristics. In order to extract the effect of each characteristic, a statistical analysis was carried out to represent the ɛr of powders with an empirical formula. A fairly good agreement was obtained between observed data and those estimated from the formula. The ɛr decreased with particle size because of the size effect of BaTiO3 and high tetragonality and density was essential to obtain high ɛr of powders.

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Dielectric permittivity (εr) of BaTiO3(BTO) powders was determined by measuring εr of slurries prepared from BTO powder and propylene carbonate as dispersion medium, followed by analyzing with a finite element methods (FEM). The εr of powders depended on their characters such as tetragonality (c/a ratio), density, particle size and specific surface area. In order to extract the effect of each character, a statistical analysis was carried out to represent the εr of powders with an empirical formula, where the c/a ratio, density and particle size were used as parameters. A fairly good agreement between observed data and those expected from the formula was obtained and the contribution of each character to the εr could be determined.