EXTREMELY LOW FREQUENCY MAGNETIC FIELD SUSCEPTIBILITY OF VISUAL DISPLAY UNITS

Extremely low frequency (ELF) magnetic field susceptibility is an index of visual display unit (VDU) quality and performance. This paper provided field measured data on the susceptibility for a large variety of VDUs. A test rig was built to study the susceptibility of VDUs to magnetic fields at fundamental and third harmonic frequencies. It was found that the susceptibility level is largely dependent on refresh rate of the VDU and the orientation of the external ELF field. It was also found that the VDU susceptibility is significantly increased in the presence of harmonic frequency magnetic fields. About 30% of the tested samples have susceptibility levels higher than that stated in IEC 1000-4-8 standard.

Effects of extremely low frequency magnetic field on anxiety level and spatial memory of adult rats

Background As the widespread use of electric devices in modern life, human are exposed to extremely low frequency magnetic fields （ELF MF） much more frequently than ever. Over the past decades, a substantial number of epidemiological and experimental studies have demonstrated that ELF MF （50 Hz） exposure is associated with increased risk of various health effects. The present study examined the effects of chronic exposure to ELF MF on anxiety level and spatial memory of adult rats. Methods The 50-Hz ELF MF was used during the whole experimental procedures and the value of magnetic field （MF） was set to 2 mT. Adult rats were divided randomly to control, MF 1 hour and MF 4 hours group. Anxiety-related behaviors were examined in the open field test and the elevated plus maze; changes in spatial learning and memory were determined in Morris water maze aRer 4 weeks of daily exposure. Results Rats in MF 4 hours group had increased anxiety-like behaviors with unaltered locomotor activity. In the Morris water maze test, rats had reduced latency to find the hidden platform and improved long-term memory of former location of platform without changes in short-term memory and locomotor activity. Conclusion Chronic ELF MF exposure has anxiogenic effect on rats, and the promoting effects on spatial learning and long-term retention of spatial memory.

Combined Effects of 50 Hz Magnetic Field and Magnetic Nanoparticles on the Proliferation and Apoptosis of PC12 Cells

Objective To investigate the bioeffects of extremely low frequency （ELF） magnetic field （MF） （50 Hz, 400 μT） and magnetic nanoparticles （MNPs） via cytotoxicity and apoptosis assays on PC12 cells. Methods MNPs modified by SiO2 （MNP-SiO2） were characterized by transmission electron microscopy （TEM）, dynamic light scattering and hysteresis loop measurement. PC12 cells were administrated with MNP-SiO2 with or without MF exposure for 48 h. Cytotoxicity and apoptosis were evaluated with MTI- assay and annexin V-FITC/PI staining, respectively. The morphology and uptake of MNP-SiO2 were determined by TEM. MF simulation was performed by Ansoft Maxwell based on the finite element method. Results MNP-SiO2 were identified as -20 nm （diameter） ferromagnetic particles. MNP-SiO2 reduced cell viability in a dose-dependent manner. MF also reduced cell viability with increasing concentrations of MNP-SiO2. MNP-SiO2 alone did not cause apoptosis in PC12 cells; instead, the proportion of apoptotic cells increased significantly under MF exposure and increasing doses of MNP-SiO2. MNP-SiO2 could be ingested and then cause a slight change in cell morphology. Conclusion Combined exposure of MF and MNP-SiO2 resulted in remarkable cytotoxicity and increased apoptosis in PC12 cells. The results suggested that MF exposure could strengthen the MF of MNPs, which may enhance the bioeffects of ELF MF.