This study evaluates the maximum theoretical exposure to radiofrequency (RF) electromag- netic fields (EMFs) from a Fifth-generation (5G) New Radio (NR) base station (BS) while using four commonly used mobile applications: YouTube for video streaming, WhatsApp for voice calls, Instagram for posting pictures and videos, and running a Video game. Three factors that might affect exposure, i.e., distance of the measurement positions from the BS, measurement time, and induced traffic, were examined. Exposure was assessed through both instantaneous and time-averaged extrapolated field strengths using the Maximum Power Extrapolation (MPE) method. The former was calculated for every measured SS-RSRP (Secondary Synchronization Reference Signal Received Power) power sample obtained with a sampling resolution of 1 second, whereas the latter was obtained using a 1-min moving average applied on the applications’ instantaneous extrapolated field strengths datasets. Regarding distance, two measurement positions (MPs) were selected: MP1 at 56 meters and MP2 at 170 meters. Next, considering the measurement time, all mobile application tests were initially set to run for 30 minutes at both MPs, whereas the video streaming test (YouTube) was run for an additional 150 minutes to investigate the temporal evolution of field strengths. Considering the traffic, throughput data vs. both instantaneous and time-averaged extrapolated field strengths were observed for all four mobile applications. In addition, at MP1, a 30-minute test without a User Equipment (UE) device was conducted to analyze exposure levels in the absence of induced traffic. The findings indicated that the estimated field strengths for mobile applications varied. It was observed that distance and time had a more significant impact than the volume of data traffic generated (throughput). Notably, the exposure levels in all tests were considerably lower than the public exposure thresholds set by the ICNIRP guidelines.INDEX TERMS 5G NR, C-band, human exposure assessment, mobile applications, traffic data, maximum extrapolation method, RF-EMF.
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Background: Acne vulgaris is a multifaceted skin disorder, affecting more than 85% of young individuals worldwide. Pharmacological therapy is not always desirable because of the development of antibiotic resistance or the potential risk of adverse effects. Non‐pharmacological therapies can be viable alternatives for conventional therapies. However, sufficient evidence‐based support in the efficacy and safety of non‐pharmacological therapies is lacking. Objective: To assess the efficacy and safety of several non‐pharmacological therapies in the treatment of acne vulgaris. Methods: A systematic literature review, including a best‐evidence synthesis, was performed to identify literature. Three electronic databases were accessed and searched for studies published between January 2000 and May 2017. Results: Thirty‐three eligible studies were included in our systematic review. Three main types of non‐pharmacological therapies were identified laser‐ and light‐based therapies, chemical peels and fractional microneedling radiofrequency. The majority of the included studies demonstrated a significant reduction in acne lesions. However, only seven studies had a high methodologic quality. Based on these seven trials, a best‐evidence synthesis was conducted. Strong evidence was found for glycolic acid (10–40%). Moderate evidence was found for amino fruit acid (20–60%), intense pulsed light (400–700 and 870–1200 nm) and the diode laser (1450 nm). Initially, conflicting evidence was found for pulsed dye laser (585–595 nm). The most frequently reported side‐effects for non‐pharmacological therapies included erythema, tolerable pain, purpura, oedema and a few cases of hyperpigmentation, which were in most cases mild and transient. Conclusion: Circumstantial evidence was found for non‐pharmacological therapies in the treatment of acne vulgaris. However, the lack of high methodological quality among included studies prevented us to draw clear conclusions, regarding a stepwise approach. Nevertheless, our systematic review including a best‐evidence synthesis did create order and structure in resulting outcomes in which a first step towards future research is generated.
In this work, in situ measurements of the radio frequency electromagnetic field exposure have been conducted for an indoor massive MIMO 5G base station operating at 26–28 GHz. Measurements were performed at six different positions (at distances between 9.94 and 14.32 m from the base station), of which four were in line-of-sight and two were in non-line-of-sight. A comparison was performed between the measurements conducted with an omnidirectional probe and with a horn antenna, for scenarios with and without a user equipment used to actively create an antenna traffic beam from the base station towards the measurement location. A maximum exposure of 171.9 mW/m2 was measured at a distance of 9.94 m from the base station. This is below 2% of the ICNIRP reference level. Moreover, the feasibility to measure the power per resource element of the Synchronization Signal Block - which can be used to extrapolate the maximum exposure level - with a conventional spectrum analyzer was shown by comparison with a network decoder.
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