Yoon-Myoung Gimm

Extremely Low Frequency Magnetic Fields Induce Spermatogenic Germ Cell Apoptosis: Possible Mechanism

The energy generated by an extremely low frequency electromagnetic field (ELF-EMF) is too weak to directly induce genotoxicity. However, it is reported that an extremely low frequency magnetic field (ELF-MF) is related to DNA strand breakage and apoptosis. The testes that conduct spermatogenesis through a dynamic cellular process involving meiosis and mitosis seem vulnerable to external stress such as heat, MF exposure, and chemical or physical agents. Nevertheless the results regarding adverse effects of ELF-EMF on human or animal reproductive functions are inconclusive. According to the guideline of the International Commission on Non-Ionizing Radiation Protection (ICNIRP; 2010) for limiting exposure to time-varying MF (1 Hz to 100 kHz), overall conclusion of epidemiologic studies has not consistently shown an association between human adverse reproductive outcomes and maternal or paternal exposure to low frequency fields. In animal studies there is no compelling evidence of causal relationship between prenatal development and ELF-MF exposure. However there is increasing evidence that EL-EMF exposure is involved with germ cell apoptosis in testes. Biophysical mechanism by which ELF-MF induces germ cell apoptosis has not been established. This review proposes the possible mechanism of germ cell apoptosis in testes induced by ELF-MF.

Continuous exposure to 60 Hz magnetic fields induces duration- and dose-dependent apoptosis of testicular germ cells

To evaluate duration- and dose-dependent effects of continuous exposure to a 60 Hz magnetic field (MF) on the testes in mice, BALB/c male mice were exposed to a 60 Hz MF at 100 μT for 24 h a day for 2, 4, 6, or 8 weeks, and at 2, 20, or 200 μT for 24 h a day for 8 weeks. Any exposures to MF did not significantly affect body or testicular masses. However, the apoptotic cells among testicular germ cells were increased duration-dependent at exposures of 100 μT for 6 and 8 weeks and dose-dependent at exposures of 20 and 200 μT for 8 weeks. The number of sperm in epididymis and the diameter of seminiferous tubule decreased in mice exposed to 100 and 200 μT for 8 weeks, respectively. To induce the apoptosis of testicular germ cell in mice, the minimum dose is 20 μT at continuous exposure to a 60 Hz MF for 8 weeks and the minimum duration is 6 weeks at continuous exposure of 100 μT. Taken together, these results suggest that continuous exposure to a 60 Hz MF might affect, duration- and dose-dependent biological processes including apoptotic cell death and spermatogenesis in the male reproductive system of mice.

Frequency Tracking of Resonance Frequency Variation of L-C Circuits for Wireless Energy Transmission to Medical Devices in Human Organs

A capsular endoscope (CE) for inspection of the large intestine requires a motor for backward navigation against the autonomous travel in the intestine. This study proposes an HF power system for generating a magnetic field and for delivering wireless power to the internal or implanted medical devices. The magnetic field is generated by a wound coil (L) around a wooden frame, and the current is driven to the coil through a resonating capacitor (C). The characteristics of the resonance frequency shifting of the L-C series circuit are analyzed. A stable magnetic field intensity in the field coil is maintained by a specially designed frequency tracking system that automatically follows the L-C resonance frequency. Testing confirmed that the oscillation system tracks well the parameter changes of the electric components caused by the operating conditions or environmental variations.

The effects of a 1.8 GHz continuous electromagnetic fields on mucociliary transport of human nasal mucosa

The aim of this study was to investigate the effects of a 1.8 GHz continuous electromagnetic fields (EMF) on human nasal mucociliary transport, and to determine the pathophysiology of ciliary beat frequency (CBF) during an EMF‐induced change.

Intracellular Ca2+ Mobilization and Beta-hexosaminidase Release Are Not Influenced by 60 Hz-electromagnetic Fields (EMF) in RBL 2H3 Cells

The effects of extremely low frequency electromagnetic fields (EMF) on intracellular Ca(2+) mobilization and cellular function in RBL 2H3 cells were investigated. Exposure to EMF (60 Hz, 0.1 or 1 mT) for 4 or 16 h did not produce any cytotoxic effects in RBL 2H3 cells. Melittin, ionomycin and thapsigargin each dose-dependently increased the intracellular Ca(2+) concentration. The increase of intracellular Ca(2+) induced by these three agents was not affected by exposure to EMF (60 Hz, 1 mT) for 4 or 16 h in RBL 2H3 cells. To investigate the effect of EMF on exocytosis, we measured beta-hexosaminidase release in RBL 2H3 cells. Basal release of beta-hexosaminidase was 12.3±2.3% in RBL 2H3 cells. Exposure to EMF (60 Hz, 0.1 or 1 mT) for 4 or 16 h did not affect the basal or 1 µM melittin-induced beta-hexosaminidase release in RBL 2H3 cells. This study suggests that exposure to EMF (60 Hz, 0.1 or 1 mT), which is the limit of occupational exposure, has no influence on intracellular Ca(2+) mobilization and cellular function in RBL 2H3 cells.

Quick SAR measurement system by 2D array E-field sensors

The safety on human body against electromagnetic fields radiating from mobile devices has been investigated for a long time. The measurement method of RF power absorption to human body from wireless devices usually adopted robot scanning in the phantom in the past. But it takes a very long time to evaluate the SAR value of a mobile device. In this paper, a quick SAR measurement system using a 2D array of E-field probes having 3 axes isotropie characteristics is proposed. It is possible to fast estimate the volume SAR by a software with the 2D surface SAR data acquired by arrayed probes deleting robot moving time.

Effect of Extremely Low Frequency Electromagnetic Fields (EMF) on Phospholipase Activity in the Cultured Cells

This study was conducted to investigate the effects of extremely low frequency electromagnetic fields (EMF) on signal pathway in plasma membrane of cultured cells (RAW 264.7 cells and RBL 2H3 cells), by measuring the activity of phospholipase A(2) (PLA(2)), phospholipase C (PLC) and phospholipase D (PLD). The cells were exposed to the EMF (60 Hz, 0.1 or 1 mT) for 4 or 16 h. The basal and 0.5 µM melittin-induced arachidonic acid release was not affected by EMF in both cells. In cell-free PLA(2) assay, we failed to observe the change of cPLA(2) and sPLA(2) activity. Also both PLC and PLD activities did not show any change in the two cell lines exposed to EMF. This study suggests that the exposure condition of EMF (60 Hz, 0.1 or 1 mT) which is 2.4 fold higher than the limit of occupational exposure does not induce phospholipases-associated signal pathway in RAW 264.7 cells and RBL 2H3 cells.

Characteristics of the Voltages between the Communication Lines and Ground Induced by the Adjacent Artificial High-Voltage or Current ELF Source

The measurements were performed to verify experimentally that the voltage arising on a telecommunication line by a power line is due to the induction phenomena because there has been an opinion that the arising voltage on a telecommunication line is not by induction, but by other causality. The voltage appeared on the telecommunication line by way of an electric field or magnetic field generated by the source apparatus that had been artificially made to provide intentional constant high-voltage or current in ELF, that is, 60 ㎐ as an emulated commercial power.

Formulation of the Sucrose-Free Simulant Human Tissue for SAR Measurement at CDMA Mobile Band

A general method to formulate the tissue-equivalent liquids for SAR measurement is proposed to make sucrose-free brain tissue applicable at 835 MHz as an example. We suggest the tissue composition can be determined by measuring the dielectric constants and conductivities with the DI water and salt addition variation to the pre-manufactured auxiliary liquid of DGBE and TritonX-100. The manufactured liquid satisfies the specified electrical parameters of international standard at 835 ㎒.

Effects of a continuous electromagnetic field on wound healing in human airway

The aim of this study was to investigate the effect of a 1.8‐GHz continuous electromagnetic field (EMF) on wound healing in a human airway cell‐culture system.