ID Number		1958
Study Type		Human / Provocation
Model		GHz/THz exposure to skin and theoretical coupling to sweat gland helical duct "antennas."
Details		Computer simulated model of human skin suggested RF in the sub-terahertz (75-110 GHz) range may directly couple with helically shaped sweat duct tubes filled with conductive sweat as low-Q antennas in a manner dependent upon active perspiration, pulse rate, and systolic blood pressure. The authors suggest the potential for remote sensing of physiological and mental parameters in subjects. AUTHORS' ABSTRACT: Betzalel et al. 2017 (IEEE #6841): In the near future, applications will come online that require data transmission in ultrahigh rates of 100 Gbit per second and beyond. In fact, the planning for new industry regulations for the exploitation of the sub-THz band are well advanced under the auspices of IEEE 802.15 Terahertz Interest Group. One aspect of this endeavor is to gauge the possible impact on human health by the expected explosion in commercial use of this band. It is, therefore, imperative to estimate the respective specific absorption rates of human tissues. In the interaction of microwave radiation and human beings, the skin is traditionally considered as just an absorbing sponge stratum filled with water. This approach is justified when the impinging wavelength is greater than the dimensions of the skin layer. However, in the sub-THz band this condition is violated. In 2008, we demonstrated that the coiled portion of the sweat duct in upper skin layer could be regarded as a helical antenna in the sub-THz band. The full ramifications of what these findings represent in the human condition are still very unclear, but it is obvious that the absorption of electromagnetic energy is governed by the topology for the skin and its organelles, especially the sweat duct. AUTHORS' ABSTRACT: Betzalel, Ishai, Feldman 2018 (IEEE #6998): In the interaction of microwave radiation and human beings, the skin is traditionally considered as just an absorbing sponge stratum filled with water. In previous works, we showed that this view is flawed when we demonstrated that the coiled portion of the sweat duct in upper skin layer is regarded as a helical antenna in the sub-THz band. Experimentally we showed that the reflectance of the human skin in the sub-THz region depends on the intensity of perspiration, i.e. sweat duct's conductivity, and correlates with levels of human stress (physical, mental and emotional). Later on, we detected circular dichroism in the reflectance from the skin, a signature of the axial mode of a helical antenna. The full ramifications of what these findings represent in the human condition are still unclear. We also revealed correlation of electrocardiography (ECG) parameters to the sub-THz reflection coefficient of human skin. In a recent work, we developed a unique simulation tool of human skin, taking into account the skin multi-layer structure together with the helical segment of the sweat duct embedded in it. The presence of the sweat duct led to a high specific absorption rate (SAR) of the skin in extremely high frequency band. In this paper, we summarize the physical evidence for this phenomenon and consider its implication for the future exploitation of the electromagnetic spectrum by wireless communication. Starting from July 2016 the US Federal Communications Commission (FCC) has adopted new rules for wireless broadband operations above 24/GHz (5/G). This trend of exploitation is predicted to expand to higher frequencies in the sub-THz region. One must consider the implications of human immersion in the electromagnetic noise, caused by devices working at the very same frequencies as those, to which the sweat duct (as a helical antenna) is most attuned. We are raising a warning flag against the unrestricted use of sub-THz technologies for communication, before the possible consequences for public health are explored.
Findings		Not Applicable to Bioeffects
Status		Completed With Publication
Principal Investigator		Hebrew University Jerusalem, Israel
Funding Agency		Private/Instit.
Country		ISRAEL
References		Feldman, Y et al. Phys Med Biol, (2009) 54:3341-3363 Feldman, Y et al. Phys Rev Lett, (2008) 100:128102-1-128102-4 Hayut, I et al. Physical Review E., (2014) 89:p. 042715- Hayut, I et al. IEEE Transactions on Terahertz Science and Technology., (2013) 3:207-215 Feldman, Y et al. Unknown., (201?) ?:x-y Betzalel, N et al. IEEE Transactions on Terahertz Science and Technology., (2017) 7:521-528 Betzalel , N et al. Environmental Research., (2018) 163:208-216 Betzalel, N et al. Environmental Research., (2020) 182:109016- Foster, KR et al. Environmental Research. , (2020) 183:109008- Baksheeva, K et al. IEEE Transactions on Terahertz Science and Technology., (2021) :-
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