Objective To investigate the effects of extremely low frequency magnetic and electric fields （ELFEMFs） emitted from 380 kV transmission lines on some leukocyte differentiation antigens in dairy cows. Methods The stu...Objective To investigate the effects of extremely low frequency magnetic and electric fields （ELFEMFs） emitted from 380 kV transmission lines on some leukocyte differentiation antigens in dairy cows. Methods The study was carded out in 5 cows exposed to 1.98-3.28 μT of ELFEMFs and in 5 control cows exposed to 0.2-0.7 μT of ELFEMFs. Following haematological and immunologic parameters were measured in both groups： WBC, CD45R, CD6, CD4, CD8, CD21, and CD11B leukocyte antigen expression. Results Some of the haematological and immunologic parameters under investigation were similar in both groups. However, CD8 （T lymphocyte surface antigen） was higher in the exposed group （1.35 ±0.120 vs 0.50 ±0.14×10^3/mL）. Furthermore, the CD4/CD8 ratio （0.84 ±0.05 and 2.19±0.16 for exposed and not exposed cows respectively） and circadian rhythm were different between the two groups. Conclusion Exposure to ELFEMFs is responsible of the abnormal temporal variations and distribution of some haematological and immunological parameters in dairy cows.展开更多
Theoretical analysis is made on the temperature field at the time of pulse current discharge in a metal structure with an elliptical embedding crack. In finding the temperature field, analogy between the current flow ...Theoretical analysis is made on the temperature field at the time of pulse current discharge in a metal structure with an elliptical embedding crack. In finding the temperature field, analogy between the current flow through an elliptical embedding crack and the fluid flow through a barrier is made based on the similarity principle. Boundary conditions derived from this theory are introduced so that the distribution of current density and the temperature field expressions can be obtained. The study provides a theoretic basis to the applications of stopping spatial crack with electromagnetic heating.展开更多
文摘Objective To investigate the effects of extremely low frequency magnetic and electric fields （ELFEMFs） emitted from 380 kV transmission lines on some leukocyte differentiation antigens in dairy cows. Methods The study was carded out in 5 cows exposed to 1.98-3.28 μT of ELFEMFs and in 5 control cows exposed to 0.2-0.7 μT of ELFEMFs. Following haematological and immunologic parameters were measured in both groups： WBC, CD45R, CD6, CD4, CD8, CD21, and CD11B leukocyte antigen expression. Results Some of the haematological and immunologic parameters under investigation were similar in both groups. However, CD8 （T lymphocyte surface antigen） was higher in the exposed group （1.35 ±0.120 vs 0.50 ±0.14×10^3/mL）. Furthermore, the CD4/CD8 ratio （0.84 ±0.05 and 2.19±0.16 for exposed and not exposed cows respectively） and circadian rhythm were different between the two groups. Conclusion Exposure to ELFEMFs is responsible of the abnormal temporal variations and distribution of some haematological and immunological parameters in dairy cows.
基金Project supported by the National Natural Science Foundation of China (No.50675190)
文摘Theoretical analysis is made on the temperature field at the time of pulse current discharge in a metal structure with an elliptical embedding crack. In finding the temperature field, analogy between the current flow through an elliptical embedding crack and the fluid flow through a barrier is made based on the similarity principle. Boundary conditions derived from this theory are introduced so that the distribution of current density and the temperature field expressions can be obtained. The study provides a theoretic basis to the applications of stopping spatial crack with electromagnetic heating.
