Novel 60 GHz Band Spatial Synthetic Exposure Setup to Investigate Biological Effects of 5G and Beyond Wireless Systems on Human Body

The global spread of 5th generation (5G) wireless systems causes some concern about health effects of millimeter waves (MMW). To investigate biological effects of local exposure to 5G-MMW on human body, a novel 60 GHz band exposure setup was developed, and its performance was validated. A spatial synthetic beam-type exposure setup using two dielectric lens antennas was proposed to achieve high intensity 60 GHz irradiation to the target area of human skin. Variety distributions and intensities of electromagnetic fields at the exposed area, which is modified by incident angles of the combined beams, were simulated using finite-difference time-domain methods. The exposure performance we estimated was verified by temperature elevations of surface in a physical arm-shaped silicone phantom during the MMW exposure. The interference fringes generated in the exposed area due to the combined two-directional beam radiations were observed both in the simulation and in the phantom experiment but eliminated by applying an orthogonalizing polarized feeding structure. Under these exposure conditions, the local temperature changes, which could evoke warmth sensations, were obtained at the target area of the human forearm skin, which means the achievement of exposure performance we intended.

Probing Elastic Anisotropy of Human Skin in Vivo With Light Using Non-Contact Acoustic Micro-Tapping OCE and Polarization-Sensitive OCT

Skin broadly protects the human body from undesired factors such as ultraviolet radiation and abrasion and helps conserve body temperature and hydration. Skin’s elasticity and its level of anisotropy are key to its aesthetics and function. Currently, however, treatment success is often speculative and subjective, and is rarely based on skin’s elastic properties because there is no fast and accurate non-contact method for imaging of skin’s elasticity. Here we report on a non-contact and non-invasive method to image and characterize skin’s elastic anisotropy. It combines acoustic micro-tapping optical coherence elastography (AmT-OCE) with a nearly incompressible transversely isotropic (NITI) model to quantify skin’s elastic moduli. In addition, skin sites were imaged with polarization sensitive optical coherence tomography (PS-OCT) to help define the fiber orientation. Forearm skin areas were investigated in five volunteers. Results clearly demonstrate elastic anisotropy of skin in all subjects. AmT-OCE has distinct advantage over competitive techniques because it provides objective, quantitative characterization of skin’s elasticity without contact, which opens the door for broad translation into clinical use. Finally, we demonstrate that a combination of multiple OCT modalities (structural OCT, OCT angiography, PS-OCT and AmT-OCE) may provide rich information about skin and can be used to characterize scaring.

Differential responsiveness of glabrous and non-glabrous skin to local transmural pressure elevations; the impact of 5 weeks of iterative local pressure loading

We examined the in vivo pressure-flow relationship in human cutaneous vessels during acute and repeated elevations of local transmural pressure. In 10 healthy men, red blood cell flux was monitored simultaneously on the non-glabrous skin of the forearm and the glabrous skin of a finger during a vascular pressure provocation, wherein the blood vessels of an arm were exposed to a wide range of stepwise increasing distending pressures. Forearm skin blood flux was relatively stable at slight and moderate elevations of distending pressure, whereas it increased ~3-4-fold at the highest levels (P = 0.004). Finger blood flux on the contrary, dropped promptly and consistently throughout the provocation (P < 0.001). Eight of the subjects repeated the provocation trial after a 5-week pressure-training regimen, during which the vasculature in one arm was exposed intermittently (40 min, 3 times･week-1) to increased transmural pressure (from +65 mmHg week-1 to +105 mmHg week-5). The training regimen diminished the pressure-induced increase in forearm blood flux by ~34% (P = 0.02), whereas it inhibited the reduction in finger blood flux (P < 0.001) in response to slight and moderate distending pressure elevations. The present findings demonstrate that, during local pressure perturbations, the cutaneous autoregulatory function is accentuated in glabrous compared to in the non-glabrous skin regions. Prolonged intermittent regional exposures to augmented intravascular pressure blunt the responsiveness of the glabrous skin, but enhance arteriolar pressure resistance in the non-glabrous skin.

Na+/K+-ATPase plays a major role in mediating cutaneous thermal hyperemia achieved by local skin heating to 39 ºC

Na+/K+-ATPase is integrally involved in mediating cutaneous vasodilation during an exercise-heat stress, which includes an interactive role with nitric oxide synthase (NOS). Here, we assessed if Na+/K+-ATPase also contributes to cutaneous thermal hyperemia induced by local skin heating, which is commonly employed to assess cutaneous endothelium-dependent vasodilation. Further, we assessed the extent to which NOS contributes to this response. Cutaneous vascular conductance (CVC) was measured continuously at four forearm skin sites in eleven young adults (4 women). After baseline measurement, local skin temperature was increased from 33 to 39 ºC to induce cutaneous thermal hyperemia. Once a plateau in CVC was achieved, each skin site was continuously perfused via intradermal microdialysis with either: 1) lactated Ringer's solution (control), 2) 6 mM ouabain, a Na+/K+-ATPase inhibitor, 3) 20 mM L-NAME, a NOS inhibitor, or 4) a combination of both. Relative the control site, CVC during the plateau phase of cutaneous thermal hyperemia (~50%max) was reduced by the lone inhibition of Na+/K+-ATPase (-19±8%max, P = 0.038) and NOS (-32±4%max, P < 0.001) as well as the combined inhibition of both (-37±9%max, P < 0.001). The magnitude of reduction was similar between NOS inhibition alone and combined inhibition (P = 1.000). The administration of Na+/K+-ATPase and NOS inhibitors fully abolished the plateau of CVC with values returning to pre-heating baseline values (P = 0.439). We show that Na+/K+-ATPase contributes to cutaneous thermal hyperemia during local skin heating to 39 ºC, and this response is partially mediated by NOS.

Two New Dexpanthenol-Containing Wash Gels: Skin Hydration, Barrier Function and Cosmetic Performance upon Single and Repeated Usage in Subjects with Dry Skin

Two novel body/face wash gels enriched with emollient ingredients (including dexpanthenol) were developed for the daily care of dry skin. Two similarly designed 2-week studies (N = 42 each) were conducted to assess the biophysical and cosmetic performance of each of the new wash gels in healthy adults with dry skin. Instrumental measurements quantified the effects of the wash gels on stratum corneum (SC) hydration and transepidermal water loss (TEWL) (with and without a previous sodium lauryl sulfate (SLS) challenge) after single and repeated usage. Following single and repeated applications of the face wash gel to facial skin, as well as to dry SLS-undamaged and SLS-damaged skin of the forearm, skin hydration significantly increased. Similarly, after single and repeated usage of the body wash gel to dry SLS-undamaged and SLS-damaged skin of the forearm, skin moisturization increased significantly from baseline; comparisons with control areas provided inconsistent results for SLS-undamaged skin. No effects on TEWL were observed for either product. Both wash gels were well tolerated and the cosmetic performances were appreciated by the subjects. The study results suggest that daily use of the new wash gels was associated with significant skin-moisturizing effects without adversely affecting skin barrier function and repair.

Changes in Skin Barrier Function after Repeated Exposition to Phospholipid-Based Surfactants and Sodium Dodecyl Sulfate In Vivo and Corneocyte Surface Analysis by Atomic Force Microscopy

(1) Background: The aim of the study was to evaluate the effect of pure lecithins in comparison to a conventional surfactant on skin in vivo. (2) Methods: Physiological skin parameters were evaluated at the beginning and the end of the study (day 1 and day 4) (n = 8, healthy forearm skin) with an Aquaflux®, skin-pH-Meter, Corneometer® and an Epsilon® sensor. Confocal Raman spectroscopy was employed to monitor natural moisturizing factor, urea and water content of the participants’ skin. Tape strips of treated skin sites were taken and the collected corneocytes were subjected to atomic force microscopy. Circular nano objects were counted, and dermal texture indices were determined. (3) Results: Transepidermal water loss was increased, and skin hydration was decreased after treatment with SDS and LPC80. Natural moisturizing factor and urea concentrations within the outermost 10 µm of the stratum corneum were lower than after treatment with S75 or water. Dermal texture indices of skin treated with SDS were higher than skin treated with water (control). (4) Conclusions: Results suggest very good (S75) or good (LPC80) skin-tolerability of lecithin-based surfactants in comparison to SDS and encourage further investigation.