No abstract

No abstract

a b s t r a c tProportions of reversible and irreversible magnetization processes in the overall magnetization process were studied in a complex view of magnetic, thermal and electrical properties of iron-phenolphormaldehyde resin composites. They were determined experimentally at different values of magnetic induction along the initial curve. The results of total, differential, reversible and irreversible permeability measurement as well as the analysis of DC energy losses revealed the same tendencies: The numbers of movable domain walls (determining the extent of reversible processes) depend on the magnetic particle size and the resin content through the demagnetizing fields produced by the particle surfaces, lowering the interaction between particles. Thermal diffusivity was compared with Hashin-Shtrikman model indicating good insulation of particles.

SUMMARY The transcript levels of three genes coding for antioxidants, Cu/Zn superoxide dismutase (SOD), catalase and phospholipid hydroperoxide glutathione peroxidase (GSH-Px), and those of two stress proteins,metallothionein (MT) and CYP1A, were examined with real-time quantitative (q)RT-PCR in hepatic tissue of Atlantic cod exposed to 46% (hypoxia), 76%(normoxia) and 145% (hyperoxia) O2 saturation (tank outlet). To evaluate the oxidative stress state, the levels of total glutathione (tGSH),reduced glutathione (GSH) and oxidized glutathione (GSSG) and subsequently the oxidative stress index (OSI), were determined in the same tissue samples. The transcript level of GSH-Px was significantly upregulated in fish exposed to hyperoxia, and significantly downregulated in fish exposed to hypoxia,compared to the normoxia group. Significant downregulation was also found for SOD and CYP1A transcriptional levels in fish exposed to hypoxia. The transcript levels of catalase and MT did not change in liver of cod exposed to suboptimal oxygen levels. No significant differences were seen between the groups for tGSH, GSH, GSSG or OSI. Prolonged exposure to unfavourable oxygen saturation levels did not alter the OSI, indicating that the antioxidant glutathione system is maintained at an unchanged level in liver of the examined cod.

No abstract