Numerical compliance testing of human exposure to electromagnetic radiation from smart-watches

Hong, Seon-Eui,Lee, Ae-Kyoung,Kwon, Jong-Hwa,Pack, Jeong-Ki Institute of Physics in association with the Ameri 2016 Physics in medicine & biology Vol.61 No.19

<P>In this study, we investigated the electromagnetic dosimetry for smart-watches. At present, the standard for compliance testing of body-mounted and handheld devices specifies the use of a flat phantom to provide conservative estimates of the peak spatial-averaged specific absorption rate (SAR). This means that the estimated SAR using a flat phantom should be higher than the SAR in the exposure part of an anatomical human-body model. To verify this, we numerically calculated the SAR for a flat phantom and compared it with the numerical calculation of the SAR for four anatomical human-body models of different ages. The numerical analysis was performed using the finite difference time domain method (FDTD). The smart-watch models were used in the three antennas: the shorted planar inverted-F antenna (PIFA), loop antenna, and monopole antenna. Numerical smart-watch models were implemented for cellular commutation and wireless local-area network operation at 835, 1850, and 2450 MHz. The peak spatial-averaged SARs of the smart-watch models are calculated for the flat phantom and anatomical human-body model for the wrist-worn and next to mouth positions. The results show that the flat phantom does not provide a consistent conservative SAR estimate. We concluded that the difference in the SAR results between an anatomical human-body model and a flat phantom can be attributed to the different phantom shapes and tissue structures.</P>

The Effect of Sub-Chronic Whole-Body Exposure to a 1,950 MHz Electromagnetic Field on the Hippocampus in the Mouse Brain

Hyung-Do Choi,Jeong-Ki Pack,Nam Kim,Yun-Sil Lee,Hae-June Lee,Jong Hwa Kwon,Ye Ji Jeong,Yeonghoon Son 한국전자파학회JEES 2015 Journal of Electromagnetic Engineering and Science Vol.15 No.3

The increasing use of mobile phones has raised public concern about the possible biological effects of radiofrequency electromagnetic field (RF-EMF) exposure on the human brain. To investigate the potential effect of RF-EMF exposure on the brain, we examined the behaviors and hippocampal morphology of C57BL/6 mice after sub-chronic exposure to RF-EMFs with a relatively high SAR level (5.0 W/kg). We applied a 2-hour daily exposure of WCDMA 1,950 MHz using a reverberation chamber that was designed for whole-body exposure for 60 days. In the behavioral tests, RF-EMF did not alter the physical activity or long-term memory of mice. Moreover, no alteration was found in the neuronal and glial cells in the hippocampus by RF-EMFs. In this study, we showed that sub-chronic whole body RF exposure did not produce memory impairment and hippocampal morphological alteration in C57BL/6 mice.

1950 MHz radiofrequency electromagnetic fields do not aggravate memory deficits in 5xFAD mice

Son, Yeonghoon,Jeong, Ye Ji,Kwon, Jong Hwa,Choi, Hyung‐,Do,Pack, Jeong‐,Ki,Kim, Nam,Lee, Yun‐,Sil,Lee, Hae‐,June Alan R. Liss 2016 Bioelectromagnetics Vol.37 No.6

<P>The increased use of mobile phones has generated public concern about the impact of radiofrequency electromagnetic fields (RF‐EMF) on health. In the present study, we investigated whether RF‐EMFs induce molecular changes in amyloid precursor protein (APP) processing and amyloid beta (Aβ)‐related memory impairment in the 5xFAD mouse, which is a widely used amyloid animal model. The 5xFAD mice at the age of 1.5 months were assigned to two groups (RF‐EMF‐ and sham‐exposed groups, eight mice per group). The RF‐EMF group was placed in a reverberation chamber and exposed to 1950 MHz electromagnetic fields for 3 months (SAR 5 W/kg, 2 h/day, 5 days/week). The Y‐maze, Morris water maze, and novel object recognition memory test were used to evaluate spatial and non‐spatial memory following 3‐month RF‐EMF exposure. Furthermore, Aβ deposition and APP and carboxyl‐terminal fragment β (CTFβ) levels were evaluated in the hippocampus and cortex of 5xFAD mice, and plasma levels of Aβ peptides were also investigated. In behavioral tests, mice that were exposed to RF‐EMF for 3 months did not exhibit differences in spatial and non‐spatial memory compared to the sham‐exposed group, and no apparent change was evident in locomotor activity. Consistent with behavioral data, RF‐EMF did not alter APP and CTFβ levels or Aβ deposition in the brains of the 5xFAD mice. These findings indicate that 3‐month RF‐EMF exposure did not affect Aβ‐related memory impairment or Aβ accumulation in the 5xFAD Alzheimer's disease model. Bioelectromagnetics. 37:391–399, 2016. © 2016 The Authors <I>Bioelectromagnetics</I> published by Wiley Periodicals, Inc. on behalf of Bioelectromagnetics Society.</P>

Long-term RF exposure on behavior and cerebral glucose metabolism in 5xFAD mice

Son, Yeonghoon,Kim, Jin Su,Jeong, Ye Ji,Jeong, Youn Kyoung,Kwon, Jong Hwa,Choi, Hyung-Do,Pack, Jeong-Ki,Kim, Nam,Lee, Yun-Sil,Lee, Hae-June Elsevier 2018 Neuroscience Letters Vol.666 No.-

<P><B>Abstract</B></P> <P>Given the increased public concern about the deleterious biological consequences of radiofrequency electromagnetic fields (RF-EMFs), the involvement of RF-EMFs in neurodegenerative diseases, especially Alzheimer’s disease (AD), has received increased consideration. To investigate the effect of long-term RF-EMF exposure on AD progression, we exposed 5xFAD mice to 1950 MHz RF-EMF at a specific absorption rate of 5.0 W/kg for 2 h/day and 5 days/week for 8 months. Behavioral changes were assessed by an open field test and an object recognition memory task after RF exposure was terminated. In addition, cerebral glucose metabolism was analyzed in the brains of the 5xFAD mice using 18F-deoxyglucose positron emission tomography. The hyperactivity-like and anxiolytic behaviors of the 5xFAD mice in open field tests were rescued by RF exposure. Furthermore, long-term RF-EMF exposure improved the cognitive deficits of 5xFAD mice that were observed in the object recognition memory test. Consistent with the behavioral changes, glucose metabolism in the hippocampus and amygdala regions of the brains of 5xFAD mice following RF exposure was significantly increased compared to glucose metabolism in the brains of sham-exposed mice. These data suggest that long-term exposure to RF-EMF might exert beneficial effects on AD in 5xFAD mice.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Chronic RF-EMF exposure improved cognitive deficits in 5xFAD mice. </LI> <LI> Chronic RF-EMF exposure rescued locomotor defects in AD-transgenic mice. </LI> <LI> Glucose metabolism was increased in the brains of 5xFAD mice after RF-EMF. </LI> </UL> </P>

Study of Pre-Classification Method for Clearance Level Through Net Peak Area Ratio in Natural Uranium-Contaminated Soil

Kyungmin Kim,Jeongwook Moon,Dong-Ju Lee,Il-Sik Kang,Dae Seong Nam,Jong Hwa Pack,Sung Jin Han,Yun Gun Jung,Heung-Ju Cho,Hongrae Jeon,Tack-Jin Kim 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.1

Natural uranium-contaminated soil in Korea Atomic Energy Research Institute (KAERI) was generated by decommissioning of the natural uranium conversion facility in 2010. Some of the contaminated soil was expected to be clearance level, however the disposal cost burden is increasing because it is not classified in advance. In this study, pre-classification method is presented according to the ratio of naturally occurring radioactive material (NORM) and contaminated uranium in the soil. To verify the validity of the method, the verification of the uranium radioactivity concentration estimation method through γ-ray analysis results corrected by self-absorption using MCNP6.2, and the validity of the pre-classification method according to the net peak area ratio were evaluated. Estimating concentration for 238U and 235U with γ-ray analysis using HPGe (GC3018) and MCNP6.2 was verified by ?-spectrometry. The analysis results of different methods were within the deviation range. Clearance screening factors (CSFs) were derived through MCNP6.2, and net peak area ratio were calculated at 295.21 keV, 351.92 keV(214Pb), 609.31 keV, 1120.28 keV, 1764.49 keV(214Bi) of to the 92.59 keV. CSFs for contaminated soil and natural soil were compared with U/Pb ratio. CSFs and radioactivity concentrations were measured, and the deviation from the 60 minute measurement results was compared in natural soil. Pre-classification is possible using by CSFs measured for more than 5 minutes to the average concentration of 214Pb or 214Bi in contaminated soil. In this study, the pre-classification method of clearance determination in contaminated soil was evaluated, and it was relatively accurate in a shorter measurement time than the method using the concentrations. This method is expected to be used as a simple pre-classification method through additional research.

Effects of 915 MHz Radiofrequency Identification Electromagnetic Field Exposure on Neuronal Precursor Cells in the Dentate Gyrus of Adult Rat Brains

Nam Kim,Young Hwan Ahn,Hye Sun Kim,Yu Hee Lee,Yun-Sil Lee,Hyung Do Choi,Jong Hwa Kwon,Jeong-Ki Pack 한국전자파학회JEES 2015 Journal of Electromagnetic Engineering and Science Vol.15 No.3

To explore the effects of radiofrequency electromagnetic field on the fate of neuronal cells, we investigated whether exposure to 915 MHz radiofrequency identification (RFID) caused morphological changes in neuronal cells in rat hippocampal dentate gyrus (DG). A reverberation chamber was used as a whole-body RFID exposure system. Rats were assigned to two groups: sham- and RFID-exposed groups. Rats in the RFID-exposed group were exposed to RFID at 4 W/kg specific absorption rate (SAR) for 8 hours daily, 5 days per week, for 2 weeks. Morphological evaluation of DG was performed using immunohistochemistry with doublecortin (DCX) as a neuronal precursor cell marker and neuronal nuclei (NeuN) as a mature neuronal cell marker. No significant morphological changes in DCX+ or NeuN+ cells in the DG of RFID-exposed rats were observed. These results suggest that RFID exposure induces no significant change in DCX+ neuronal precursor or NeuN+ neuronal cells in DG of rats.