Ultraviolet radiation sensors: a review

Novel elastomeric spiropyran-doped poly(dimethylsiloxane) optical waveguide for UV sensing

Novel poly(dimethylsiloxane) (PDMS) doped with two different spiropyran derivatives (SP) were investigated as potential candidates for the preparation of elastomeric waveguides with UV-dependent optical properties. First, free-standing films were prepared and evaluated with respect to their photochromic response to UV irradiation. Kinetics, reversibility as well as photofatigue and refractive index of the SP-doped PDMS samples were assessed. Second, SP-doped PDMS waveguides were fabricated and tested as UV sensors by monitoring changes in the transmitted optical power of a visible laser (633 nm). UV sensing was successfully demonstrated by doping PDMS using one spiropyran derivative whose propagation loss was measured as 1.04 dB/cm at 633 nm, and sensitivity estimated at 115% change in transmitted optical power per unit change in UV dose. The decay and recovery time constants were measured at 42 and 107 s, respectively, with an average UV saturation dose of 0.4 J/cm2. The prepared waveguides exhibited a reversible and consistent response even under bending. The sensor parameters can be tailored by varying the waveguide length up to 21 cm, and are affected by white light and temperatures up to 70 ℃. This work is relevant to elastomeric optics, smart optical materials, and polymer optical waveguide sensors.

Skin Cancer Prevention across the G7, Australia and New Zealand: A Review of Legislation and Guidelines

Incidence rates of melanoma and keratinocyte skin cancers have been on the rise globally in recent decades. While there has been a select focus on personal sun protection awareness, to our knowledge, there is a paucity of legislation in place to help support citizens' efforts to protect themselves from the harmful effects of ultraviolet radiation (UVR). Given this, we conducted a comprehensive review of legislation and guidelines pertaining to a variety of sun protection-related topics in countries of the Group of Seven (G7), Australia and New Zealand. Australia was the only country to have banned tanning beds for individuals of all ages, while other select countries have instituted bans for minors. In workplace policy, there is very little recognition of the danger of occupational UVR exposure in outdoor workers, and thus very few protective measures are in place. With regard to sports and recreation, certain dermatological/professional associations have put forward recommendations, but no legislation was brought forward by government bodies outside of Australia and New Zealand. With regard to youth, while there are various guidelines and frameworks in place across several countries, adherence remains difficult in the absence of concrete legislation and standardization of procedures. Finally, only Australia and a few select jurisdictions in the United States have implemented sales tax exemptions for sunscreen products. In light of our findings, we have made several recommendations, which we anticipate will help reduce the rates of melanoma and keratinocyte cancers in years to come. However, minimizing UVR exposure is not without risk, and we, therefore, suggest the promotion of vitamin D supplementation in conjunction with sun protective practices to limit potential harm.

Vitamin D insufficiency and its contributing factors in primary school-aged children in Indonesia, a sun-rich country

PURPOSE

The prevalence of rickets is increasing worldwide in association with an increase in vitamin D deficiency. This study aimed to investigate the vitamin D profile of healthy school-aged children in a sun-rich country and its contributing factors.

METHODS

This cross-sectional study was conducted in 120 healthy children from 7-12 years of age who live in Jakarta, Indonesia. Their demographic status, sun exposure duration time, and lifestyle were recorded using a structured questionnaire. Serum calcium, phosphate, bone-alkaline phosphatase (B-ALP), and 25-hydroxy vitamin D (25(OH)2D3) levels were measured. The participants were categorized into vitamin D sufficient and non-vitamin D sufficient groups, and we analyzed variables that contributed to the 25(OH)2D3 level.

RESULTS

Of the participants, 73 (60.8%) were vitamin D sufficient, 45 (37.5%) were vitamin D insufficient, and 2 (1.7%) were vitamin D deficient. Sex, age, body mass index, Fitzpatrick skin type, daily milk intake, and clothing type were not different between the vitamin D sufficient and non-vitamin D sufficient groups. There were no differences in serum calcium, phosphate, and B-ALP between the 2 groups. Sun exposure time was significantly longer in the vitamin D sufficient group compared with that in the non-vitamin D sufficient group (511.4 min/wk vs. 318.7 min/wk, P=0.004), and this effect remained consistent on multivariate analysis after adjustment for covariates (adjusted odds ratio, 1.002; 95% confidence interval, 1.000-1.003). More participants in the vitamin D sufficient group did not use sunscreen (59 vs. 27, P=0.02), but this finding was inconsistent with our multivariate analysis.

CONCLUSION

Despite year-round sun exposure, approximately 1 in 3 primary school-aged children had insufficient vitamin D level. Sun exposure duration was a major contributing factor.

Review of Wearable and Portable Sensors for Monitoring Personal Solar UV Exposure

Sunlight is one of the main environmental resources that keeps all the organisms alive on earth. The ultraviolet (UV) radiation from the sun is essential for vitamin D synthesis in the human body, which is crucial for bone and muscle health. In addition, sun exposure also helps to reduce the risk of some cardiovascular diseases and cancers. However, excessive UV exposure can lead to adverse effects, including some eye diseases, premature aging, sunburn and skin cancers. The solar UV irradiance itself depends on many environmental factors. In fact, the UV index reported in weather forecasts is an estimation under cloudless conditions. Personal UV exposure also depends on one's outdoor activities and habits. Furthermore, the UV intake depends on the skin sensitivity. Therefore, there is a need for research into monitoring the optimal daily UV exposure for health benefits, without developing potential health risks. To facilitate the monitoring of solar UV intensity and cumulative dose, a variety of UV sensors have been developed in the past few decades and many are commercially available. Examples of sensors being marketed are: portable UV dosimeter, wearable UV radiometer, personal UV monitor, and handheld Solarmeter®. Some of the UV sensors can be worn as personal health monitors, which promote solar exposure protection. The paper provides a comprehensive review of the wearable and portable UV sensors for monitoring personal UV exposure, including a discussion of their unique advantages and limitations. Proposals are also presented for possible future research into reliable and practical UV sensors for personal UV exposure monitoring.

A novel efficient broadband model to derive daily surface solar Ultraviolet radiation (0.280-0.400 μm)

The climatic characteristics of solar Ultraviolet radiation (UV) are of vital important for the climate change and photochemical reactions. High-quality records of solar UV radiation are the premise for solar UV researches and applications, but solar UV radiation observations are sparse around the world. Among all wavelength of UV radiations, only UVA (0.315-0.400 nm) and UVB (0.280-0.315 nm) could reach the earth surface. This study attempted to develop a novel efficient physically broadband parameterization (hereafter, FASTUV) for estimating surface solar UV radiation (0.280-0.400 μm) in all-sky conditions based on Leckner's spectral model for calculating shortwave solar radiation, using MERRA_2 reanalysis data. The Quadratic polynomial formula and artificial neural networks were used to calculate the cloud transmittance for UV, using sunshine durations measurements at 2474 CMA stations. The surface solar UV radiation measurements at 29 CERN (The Chinese Ecosystem Research Network) stations were used for validating the estimated UV values. The result showed the FASTUV model could be used for estimating UV values with high accuracy, strong robustness and fast speed. Then, the spatial and temporal variation of surface solar UV radiation in China were revealed. The result indicated that the Qinghai Tibetan Plateau and the Palmier Plateau has always been the areas with highest UV values, while the Northeastern China is the area with the lowest UV values. Meanwhile, the FASTUV model have been packaged into a software namely 'FASTUV_V1.0'. We provide the executable file of FASTUV model in publicly available repository: https://doi.org/10.6084/m9.figshare.11409666.

Solar Ultraviolet Exposure in Individuals Who Perform Outdoor Sport Activities

BACKGROUND

Skin cancer is the most common cancer in the USA. Therefore, it is important to review the contribution of ultraviolet radiation (UVR) exposure to skin cancer in individuals with the highest risk. Documenting the relationship between outdoor sports solar ultraviolet exposure and their risk of skin cancer along with appropriate risk mitigation strategies can help inform clinicians of practical information for counseling sun protective behaviors in this population.

METHODS

We conducted a review of the current evidence using PubMed to answer the following research questions: (1) How is ultraviolet radiation measured? (2) What is the modern utility of the ultraviolet index in modifying recreational sun protection behaviors? (3) What is the risk of developing skin cancer for outdoor sport participants? (4) What is the prevalence of skin cancer in sport participants? and (5) Is the number of nevi and solar lentigines elevated in outdoor sport participants?

RESULTS

Based on the literature, individuals who practice outdoor sport-related activities receive high ultraviolet radiation exposure, have a high risk for skin cancer, have a high prevalence for pigmented lesions, and may benefit from electronic sun protection educational interventions.

CONCLUSIONS

Individuals who practice outdoor sports experience substantially higher ultraviolet radiation exposure, routinely exceed the recommended exposure limits, and are at a higher risk of developing skin cancer. Therefore, those who are frequently engaged in outdoor leisure activities should be coached about efficient sun protective practices and relevant mobile technologies that may facilitate adherence.

Fond memories of my PhD research in Professor Cris dos Remedios' laboratory

I completed my PhD in 2013 under the supervision of Prof Cristobal G. dos Remedios, Department of Anatomy and Histology, The University of Sydney. His guidance and exemplary scientific standard in his laboratory ignited an insatiable scientific curiosity that continuously pushes me towards new knowledge through my own research.