The valence state of thallium affecting its toxicity, distribution and mobility, photoxidation reaction of Tl(I) was studied under the radiation from high-pressure arc mercury light or solar light. The results show that the low pH, the strong light intensity and UVB and VUC region are in favor of the photoxidation of Tl(I). In the case of pH = 2, only less than 1% Tl(I) remained in the solution after 10 min of irradiation, while pH = 9, with about 83% Tl(I) in the solution after 1 h of irradiation. After 5 min of irradiation, if the distance between the light source and the surface of solution is 20cm, just 4% Tl(I) remained in the solution, while the distance is 36 cm, still remained about 50%. 90% Tl(I) remained in filtered light, while less than 1% Tl(I) still remained in non-filtered light. The microorganic effect is not obvious comparing with photoxidation effect in this experiment, the remained Tl(I) in excluding microorganic and microorganic experiment are all about 70%.
To study the effects of extremely low frequency electromagnetic fields (ELF EMFs) on apoptosis and cell cycle of mouse brain and liver cells.Mice were exposed to 50 Hz, 0.2 mT or 6.0 mT electromagnetic fields for 2 weeks. TUNEL and flow cytometric methods were used to analyze apoptosis and cell cycle of brain and liver cells.After exposure to 0.2 mT and 6.0 mT ELF EMFs for 2 weeks, apoptosis rates of brain cells [(5.60 +/- 1.47)% and (4.73 +/- 0.48)% respectively] were higher than that of control [(2.90 +/- 0.75)%], and apoptosis rates of liver cells [(4.19 +/- 2.08)% and (3.38 +/- 0.65)% respectively] were higher than that of control [(1.84 +/- 0.76)%]. G0/G1 cell percentage of brain cells [(80.21 +/- 1.68)% and (79.54 +/- 0.56)% respectively] were higher than that of control [(76.85 +/- 0.83)%], and those of liver cells [(79.42 +/- 1.80)% and (80.47 +/- 1.79)% respectively] were higher than that of control [(73.36 +/- 3.10)%]. The above differences were all statistically significant as P < 0.05. At the same time S and G2 + M cell percentage of brain and liver cells were significantly decreased.Exposure to 50 Hz EMFs may alter cell cycle and induce apoptosis of mouse brain and liver cells.
To study the effects of extremely low frequency electromagnetic fields (ELF EMFs) on c-fos gene expression in mouse brain and liver tissues.Mice were exposed to 50 Hz sinusoidal 0.2 mT or 6.0 mT electromagnetic field for 2 weeks or 4 weeks. Competitive RT-PCR method was used to measure c-fos mRNA level.After exposure to 0.2 mT or 6.0 mT field for 2 weeks, c-fos mRNA levels in brain tissue [(0.0178 +/- 0.0076) amol/120 ng cDNA and (0.0092 +/- 0.0042) amol/120 ng cDNA respectively] were higher than that of control level [(0.0012 +/- 0.0005) amol/120 ng cDNA] (P < 0.05). In liver tissue c-fos mRNA levels [(0.0117 +/- 0.0055) amol/120 ng cDNA and (0.0148 +/- 0.0162) amol/120 ng cDNA respectively] were also higher than that of control level [(0.0005 +/- 0.0005) amol/120 ng cDNA] (P < 0.05). After exposure to 0.2 mT or 6.0 mT field for 4 weeks, c-fos mRNA levels in brain tissue [(0.0100 +/- 0.0054) amol/120 ng cDNA and (0.0198 +/- 0.0079) amol/120 ng cDNA respectively] were higher than that of control level [(0.0015 +/- 0.0008) amol/120 ng cDNA] (P < 0.05). In liver tissue the exposure induced much higher expression level [(0.0173 +/- 0.0122) amol/120 ng cDNA and (0.0133 +/- 0.0090) amol/120 ng cDNA respectively] while no expression was found in the control.Exposure to 50 Hz electromagnetic fields may induce up-regulation of c-fos transcription in mouse brain and liver tissue.
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