Multimarker Approach to Evaluate the Exposure to Electromagnetic Fields at 27 GHz (5g) On Danio rerio larvae

5G technology is evolving to satisfy several service requirements favoring high data-rate connections and lower latency times than current ones (< 1ms). 5G systems use different frequency bands of the radio wave spectrum, taking advantage of higher frequencies than previous mobile radio generations. In order to guarantee a capillary coverage of the territory for high reliability applications, it will be necessary to install a large number of repeaters because higher frequencies waves have a lower capacity to propagate in free space. Following the introduction of this new technology, there has been a growing concern about possible harmful effects on human health. The aim of this study is investigating possible short term effects induced by 5G-millimeter waves on embryonic development of Danio rerio. We have exposed fertilized eggs to 27 GHz frequency, 9.7 mW/cm2 incident power density, 23 dbm and have measured several endpoints every 24 hours. The exposure to electromagnetic fields at 27 GHz (5G) caused no significant impacts on mortality nor on morphology because the exposed larvae showed a normal detachment of the tail, presence of heart-beat and well-organised somites. A weak positivity on exposed larvae has been highlighted by immunohistochemical analysis.

Through-scalp deep-brain stimulation in tether-free, naturally-behaving mice with widefield NIR-II illumination

Neural modulation techniques with electricity, light and other forms of energy have enabled the deconstruction of neural circuitry. One major challenge of existing neural modulation techniques is the invasive brain implants and the permanent skull attachment of an optical fiber for modulating neural activity in the deep brain. Here we report an implant-free and tether-free optical neuromodulation technique in deep-brain regions through the intact scalp with brain-penetrant second near-infrared (NIR-II) illumination. Macromolecular infrared nanotransducers for deep-brain stimulation (MINDS) demonstrate exceptional photothermal conversion efficiency of 71% at 1064 nm, the wavelength that minimizes light attenuation by the brain in the entire 400-1700 nm spectrum. Upon widefield 1064-nm illumination >50 cm above the mouse head at a low incident power density of 10 mW/mm2, deep-brain neurons are activated by MINDS-sensitized TRPV1 channels with minimal thermal damage. Our approach could open opportunities for simultaneous neuromodulation of multiple socially interacting animals by remotely irradiating NIR-II light to stimulate each subject individually.

Antenna/Body Coupling in the Near-Field at 60 GHz: Impact on the Absorbed Power Density

Wireless devices, such as smartphones, tablets, and laptops, are intended to be used in the vicinity of the human body. When an antenna is placed close to a lossy medium, near-field interactions may modify the electromagnetic field distribution. Here, we analyze analytically and numerically the impact of antenna/human body interactions on the transmitted power density (TPD) at 60 GHz using a skin-equivalent model. To this end, several scenarios of increasing complexity are considered: plane-wave illumination, equivalent source, and patch antenna arrays. Our results demonstrate that, for all considered scenarios, the presence of the body in the vicinity of a source results in an increase in the average TPD. The local TPD enhancement due to the body presence close to a patch antenna array reaches 95.5% for an adult (dry skin). The variations are higher for wet skin (up to 98.25%) and for children (up to 103.3%). Both absolute value and spatial distribution of TPD are altered by the antenna/body coupling. These results suggest that the exact distribution of TPD cannot be retrieved from measurements of the incident power density in free-space in absence of the body. Therefore, for accurate measurements of the absorbed and epithelial power density (metrics used as the main dosimetric quantities at frequencies > 6 GHz), it is important to perform measurements under conditions where the wireless device under test is perturbed in the same way as by the presence of the human body in realistic use case scenarios.