Background/aim: The widespread use of fifth-generation 5G millimeter-waves (MMW) generates concern about potential adverse health effects. The latest international guidelines for MMW exposure adopt an absorbed power density (APD) of 200 W/m to avoid a local temperature rise of 5°C in human tissues as an operational adverse health effect threshold. However, because APD is estimated by simulations using human tissue models, it is unknown whether a similar value can be confirmed for living tissues. The aim of this study was to investigate the relationship between APD and skin temperature rise in vivo, and to validate the estimated values.
Materials And Methods: The rat dorsal skin was locally exposed to a 26.5 GHz quasi-MMW (qMMW) for 18 min using a patch antenna. The qMMW exposure intensities estimated by dosimetry were set to 0-500 W/m of APD. The temperatures in the dorsal skin and rectum were simultaneously measured during exposure.
Results: The qMMW-induced local temperature increase at different sites. The dorsal skin temperature increased by approximately 11.3°C at a maximum intensity of 500 W/m, but the rectal temperature increased by only 0.6°C, indicating highly localized effects of exposure to rats. A significant correlation was observed between APD and skin temperature rise. The relationship provided a linear regression model, and a temperature rise of less than 5°C was estimated in the skin exposed to 200 W/m of APD.
Conclusion: These results suggest that the operational threshold for the MMW exposure guidelines is valid under the present experimental conditions using rats.
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http://dx.doi.org/10.21873/invivo.13306 | DOI Listing |
Adv Sci (Weinh)
January 2025
Information Materials and Intelligent Sensing Laboratory of Anhui Province, Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education, Institutes of Physical Science and Information Technology, Anhui University, 111 Jiu Long Road, Hefei, 230601, China.
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View Article and Find Full Text PDFPhys Rev Lett
December 2024
Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
We consider a half-filled Chern band and its transport properties in two phases that it may form: the electronic Fermi liquid and the composite-fermion Fermi liquid. For weak disorder, we show that the Hall resistivity for the former phase is very small, while for the latter it is close to 2h/e^{2}, independent of the distribution of the Berry curvature in the band. At rising temperature and high frequency, we expect the Hall resistivity of the electronic phase to rise, and that of the composite-fermion phase to deviate from 2h/e^{2}.
View Article and Find Full Text PDFInorg Chem
January 2025
School of Chemistry and Chemical Engineering, Nanchang University, Nanchang 330031, P. R. China.
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View Article and Find Full Text PDFSci Rep
January 2025
SINTEF, Department of Health Research and Department of Circulation and Medical Imaging, The Norwegian University of Science and Technology NTNU, 7491, Trondheim, Norway.
The transport of drugs into tumor cells near the center of the tumor is known to be severely hindered due to the high interstitial pressure and poor vascularization. The aim of this work is to investigate the possibility to induce acoustic streaming in a tumor. Two tumor cases (breast and abdomen) are simulated to find the acoustic streaming and temperature rise, while varying the focused ultrasound transducer radius, frequency, and power for a constant duty cycle (1%).
View Article and Find Full Text PDFSci Rep
January 2025
Department of Mathematical Sciences, United Arab Emirates University, P.O. Box 15551, Al Ain, Abu Dhabi, United Arab Emirates.
In response to the ongoing quest for more efficient renewable energy sources, this research addresses a significant gap in understanding the performance variations of Solar Chimney Power Plant (SCPP) models, particularly focusing on the influence of flow parameters in full and half-inclined collector sections featuring semi-elliptical curvature. The motivation stems from the need to optimize SCPP designs for enhanced energy generation while minimizing resource utilization and environmental impact. This research focuses on investigating flow parameter variations in Solar Chimney Power Plant (SCPP) models with full and half-inclined collector sections featuring semi-elliptical curvature and variable semi-minor heights (b: 0.
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