Noa Betzalel
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Noa Betzalel has a total of 12 co-authors. Here are the top co-authors by number of shared publications:
Alexander Puzenko
Department of Applied Physics, The Hebrew University of Jerusalem, Jerusalem, Israel
1 shared publication- Anna Kochnev Goldstein
Department of Electrical Engineering, Stanford University
1 shared publication - Gregory Goltsman
Moscow State Pedagogical University
1 shared publication - Ksenia A. Baksheeva
Moscow Pedagogical State University, Moscow, Russia
1 shared publication - Nickolay V. Kinev
Kotel’nikov Institute of Radio Engineering and Electronics
1 shared publication Paul Ben Ishai
The Department of Physics Ariel University Ariel Israel
1 shared publication
Latest Publications
- 23 April 2021
- Published by Wiley in Journal of Biophotonics
- Vol. 14 (7) , e202100027
The AC conductivity of human sweat ducts as the dominant factor in the sub‐THz reflection coefficient of skin
The helical nature of human sweat ducts, combined with the morphological and dielectric properties of skin, suggests electromagnetic activity in the sub‐THz frequency band. A detailed electromagnetic simulation model of the skin, with embedded sweat ducts, was created. The model includes realistic dielectric properties based on the measured water content of each layer of skin, derived from Raman Spectroscopy. The model was verified by comparing it to measurements of the reflection coefficient of the palms of 13 volunteers in the frequency band 350–410 GHz. They were subjected to a measurement protocol intended to induce mental stress, thereby also activating the sweat glands. The Galvanic Skin Response was concurrently measured. Using the simulation model the optimal ac‐conductivity for each measurement was found. The range of variation for all subjects was found to be from 100 S/m to a maximum value of 6000 S/m with averages of 1000 S/m. These are one order of magnitude increase from the accepted values for water at these frequencies (~100 s/m at 100 GHz). Considering the known biochemical mechanism for inducing perspiration, we conclude that these ac‐conductivity levels are probably valid, even though the real time measurements of sweat ac‐conductivity levels inside the duct are inaccessible.
- 23 April 2021
- Published by Wiley in Journal of Biophotonics
- Vol. 14 (7) , e202100027
The AC conductivity of human sweat ducts as the dominant factor in the sub‐THz reflection coefficient of skin
The helical nature of human sweat ducts, combined with the morphological and dielectric properties of skin, suggests electromagnetic activity in the sub‐THz frequency band. A detailed electromagnetic simulation model of the skin, with embedded sweat ducts, was created. The model includes realistic dielectric properties based on the measured water content of each layer of skin, derived from Raman Spectroscopy. The model was verified by comparing it to measurements of the reflection coefficient of the palms of 13 volunteers in the frequency band 350–410 GHz. They were subjected to a measurement protocol intended to induce mental stress, thereby also activating the sweat glands. The Galvanic Skin Response was concurrently measured. Using the simulation model the optimal ac‐conductivity for each measurement was found. The range of variation for all subjects was found to be from 100 S/m to a maximum value of 6000 S/m with averages of 1000 S/m. These are one order of magnitude increase from the accepted values for water at these frequencies (~100 s/m at 100 GHz). Considering the known biochemical mechanism for inducing perspiration, we conclude that these ac‐conductivity levels are probably valid, even though the real time measurements of sweat ac‐conductivity levels inside the duct are inaccessible.
- 17 March 2021
- Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Transactions on Terahertz Science and Technology
- Vol. 11 (4) , 381-388
The Sub-THz Emission of the Human Body Under Physiological Stress
We present evidence that in the sub-THz frequency band, human skin can be considered as an electromagnetic bio-metamaterial in which its natural emission is a product of skin tissue geometry and embedded structures. Radiometry was performed on 32 human subjects from 480 to 700 GHz. Concurrently, the subjects were exposed to stress, while heart pulse rate (PS) and galvanic skin response (GSR) were also measured. The results are substantially different from the expected blackbody radiation signal of the skin surface. PS and GSR correlate to the emissivity. Using a simulation model for the skin, we find that the sweat duct is a critical element. The simulated frequency spectra qualitatively match the measured emission spectra and show that our sub-THz emission is modulated by our level of mental stress. This opens avenues for the remote monitoring of the human state.
- 17 March 2021
- Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Transactions on Terahertz Science and Technology
- Vol. 11 (4) , 381-388
The Sub-THz Emission of the Human Body Under Physiological Stress
We present evidence that in the sub-THz frequency band, human skin can be considered as an electromagnetic bio-metamaterial in which its natural emission is a product of skin tissue geometry and embedded structures. Radiometry was performed on 32 human subjects from 480 to 700 GHz. Concurrently, the subjects were exposed to stress, while heart pulse rate (PS) and galvanic skin response (GSR) were also measured. The results are substantially different from the expected blackbody radiation signal of the skin surface. PS and GSR correlate to the emissivity. Using a simulation model for the skin, we find that the sweat duct is a critical element. The simulated frequency spectra qualitatively match the measured emission spectra and show that our sub-THz emission is modulated by our level of mental stress. This opens avenues for the remote monitoring of the human state.