Sun Protection Policies and Practices in Preschool and Elementary Schools in Andalusia (Spain)

Sun exposure in childhood is a major risk factor for the development of skin cancer as an adult. School children spend much of their time outdoors exposed to ultraviolet radiation during recreational and sports activities. Skin cancer incidence tripled from 1978 to 2002 in Spain. Andalusia, the largest and sunniest region of Spain, lacks data on the sun protection measures taken in schools. To address this deficit, the aim of this study was to determine photoprotection practices and policies in preschools and primary schools in Andalusia. This descriptive study involved the administration of an online questionnaire completed by principals regarding school sun protection policies and practices. Preschool and primary schools were selected from the database of the Ministry of Education of the Andalusian Regional Government. Information of interest included photoprotection policies, students' sun protection knowledge, sun protection measures, relevant curricular content, and availability of shade at the school. A total of 2425 schools were contacted. Of them, 420 schools responded (17.31%), with the highest number of responses received from Malaga (23.8%) and Seville (19.5%) provinces. Of those responding, 67.1% of the schools did not have written sun protection policies. The photoprotection measures reported included mandatory use of a cap or hat (3.3%), use of sunglasses in outdoor areas (30%), and active encouragement of students to use sunscreen (50.7%). Roughly 24% of schools evaluated their shaded areas, with 52.9% reporting insufficient protection for most activities. The study results showed that photoprotection policies and practices in Andalusian schools were mostly insufficient. Given that skin cancer incidence has increased considerably over the last decade, it is important to concentrate on improving primary prevention practices. Additionally, photoprotection programs in schools have been shown to improve children's knowledge, attitudes, and habits regarding photoprotection. Thus, it is essential for Andalusian preschools and primary schools to develop policies and strategies to help reduce children's sun exposure while at school.

Sun Exposure and Photoprotection: Habits, Knowledge and Attitudes Among Elite Kitesurfers

Kitesurfing is one of many water sports that are growing in popularity throughout the world. In such sports, practitioners are exposed not only to direct sunlight but also to reflection from the water surface, which aggravates the impact of solar radiation on the skin. This study sought to analyse the photoprotection and photoexposure habits and knowledge of elite kitesurfers and their beliefs and attitudes in this respect. A sample of convenience of 72 male kitesurfers completed a validated questionnaire in full. By Fitzpatrick phototype, the most common classes were types I and II (69.4%). On average, kitesurfers had been practising their sport for 10.93 years, at a rate of 13.93 h per week. During the last sports season, 84.7% of respondents had suffered at least one sunburn, while 43.1% had been sunburned at least three times. The sun protection practice most commonly adopted was the use of sunscreen cream, which was used by 79.2% of respondents. Although 43.2% of respondents recognized to be worried about they might get skin cancer from the sun, 31.9% does not like using sunscreen and 44.4% like sunbathing. Regarding the respondents' knowledge of facts about sun exposure, the average rate of correct answers for the items evaluated was 66.9%. In conclusion, elite kitesurfers are potentially exposed to dangerous levels of UV radiation, which caused numerous sunburn episodes during the last sports season. It is necessary to raise these athletes' awareness of their risk of developing skin cancer and of the need to improve their sun protection and skin surveillance practices.

Different ways of estimating the amount of individual sun exposure

Linked article: Souedi et al. Br J Dermatol 2022; 186:266-273. The sun is the main source of exposure people have to ultraviolet radiation (UVR). Sun exposure has some health benefits but also some adverse effects (for example sunburn and skin cancer). Studies about the link between UVR exposure and long-term health outcomes have used a number of different ways to try and accurately measure how much UVR individuals have been exposed to. We set out to study how accurate three different ways of measuring exposure to UVR were over 6 months: (1) ambient UVR levels, (2) self-reported time spent outdoors, and (3) a statistical formula. The participants in this study were employees who worked either indoors or outdoors in Catalunya - Spain during the summer and winter months. Using a wristwatch with a dosimeter (a device made specifically to measure solar UVR levels) we measured each of the participants UVR levels daily during their working hours. Using a statistical formula, we calculated the daily dose of solar UVR each participant received by including their measured levels (from the dosimeter), the general ambient UVR levels of that day, and self-reported time spent outdoors. We then compared the results. Of our 39 participants, not surprisingly, we noted that the levels of UVR were higher for outdoor workers and during the summer. We discovered that the calculated levels and the self-reported time spent outdoors (methods 2 and 3) were more accurate than measuring general ambient UVR levels (method 1) alone. These results will be helpful to researchers who are deciding which are the best methods to use in future studies about the health effects of UVR exposure.

An Update on Vitamin D Deficiency in the twenty-first century: nature and nurture

PURPOSE OF REVIEW

Here, we review the most up-to-date understanding of the pathogenesis, prevention and treatment of vitamin D deficient rickets in children. This will include recent advances in the genetic determinants of abnormal vitamin D metabolism, with the intention of aiding clinicians with establishing the diagnosis and implementing treatment plans for children presenting with vitamin D deficiency rickets.

RECENT FINDINGS

Vitamin D deficiency rickets is a frequently encountered, but entirely preventable, disorder of bone mineral metabolism. Risk factors for developing vitamin D deficiency rickets include inadequate exposure to sunlight, exclusive breast feeding without vitamin D supplementation and inadequate intake of vitamin D, calcium or phosphorus. Other factors that may influence the development of vitamin D deficiency and/or rickets include genetic alterations or medications that alter vitamin D metabolism.

SUMMARY

Vitamin D levels in individuals are influenced by environmental factors, as well as genetic factors. A thorough understanding of these factors is critical for the evaluation and treatment of a child presenting with rickets. There remains a great need for additional research to determine ideal vitamin D status across diverse populations, and to better understand how vitamin D status affects overall health.

Association Between Time Spent Outdoors and Risk of Multiple Sclerosis

BACKGROUND AND OBJECTIVES

This study aims to determine the contributions of sun exposure and ultraviolet radiation (UVR) exposure to risk of pediatric-onset multiple sclerosis (MS).

METHODS

Children with MS and controls recruited from multiple centers in the United States were matched on sex and age. Multivariable conditional logistic regression was used to investigate the association of time spent outdoors daily in summer, use of sun protection, and ambient summer UVR dose in the year before birth and the year before diagnosis with MS risk, with adjustment for sex, age, race, birth season, child's skin color, mother's education, tobacco smoke exposure, being overweight, and Epstein-Barr virus infection.

RESULTS

Three hundred thirty-two children with MS (median disease duration 7.3 months) and 534 controls were included after matching on sex and age. In a fully adjusted model, compared to spending <30 minutes outdoors daily during the most recent summer, greater time spent outdoors was associated with a marked reduction in the odds of developing MS, with evidence of dose-response (30 minutes-1 hour: adjusted odds ratio [AOR] 0.48, 95% confidence interval [CI] 0.23-0.99, p = 0.05; 1-2 hours: AOR 0.19, 95% CI 0.09-0.40, p < 0.001). Higher summer ambient UVR dose was also protective for MS (AOR 0.76 per 1 kJ/m2, 95% CI 0.62-0.94, p = 0.01).

DISCUSSION

If this is a causal association, spending more time in the sun during summer may be strongly protective against developing pediatric MS, as well as residing in a sunnier location.

Photoprotection for skin of all color: Consensus and clinical guidance from an expert panel

The negative effects of sun exposure have become better accepted among health care professionals and the lay public over recent decades. Most attention has been focused on the effects of UV light, particularly UVB wavelengths (290-320 nm). Accordingly, products to protect skin from sunlight-associated harm (sunscreens) have been developed to minimize UVB exposure. The effects of longer wavelengths, including UVA (320-400 nm) and visible light (VL, 400-700 nm), are increasingly appreciated. VL accounts for approximately half of the solar radiation that reaches the earth's surface and understanding of its effects on the skin is improving. Studies have shown that VL can induce hyperpigmentation in individuals with dark skin types (Fitzpatrick skin types IV-VI). In addition, VL can contribute to the exacerbation of pigmentary disorders, including melasma. Because these findings are relatively new, there are gaps in understanding the needs for photoprotection and guidance for clinicians. A panel of dermatologists and photobiologists was convened to develop consensus recommendations and clinical guidance about sunscreen use relevant to the current understanding of risks associated with sun exposure using a modified Delphi method.

Cutaneous melanoma attributable to UVR exposure in Denmark and Germany

BACKGROUND

Increasing incidence rates of cutaneous melanoma (CM) observed during the last five decades in white populations are largely attributed to increased exposure to solar ultraviolet radiation (UVR), often expressed as population attributable fraction (PAF). Thus, many CMs could be prevented by reducing UVR exposure. The aim of this study was to estimate the PAF of CM attributable to UVR exposure and demographic changes in Denmark and Saarland/Germany for the period 1943 to 2036.

MATERIAL AND METHODS

CM incidence data (ICD-10, C43) for Denmark (1943-2016) and the German Federal State of Saarland (1972-2016) were retrieved from the NORDCAN database and from the Saarland Cancer Registry. The number of CMs attributable to UVR exposure was calculated by comparing contemporary or predicted CM incidence rates with CM rates in Denmark during the years 1943-1946.

RESULTS

In Denmark, the proportion of CM cases attributable to UVR exposure increased from around 20% in 1947-1951 to 96% in 2012-2016; in the Federal State of Saarland, it increased from 50% in 1972-1976 to 90% in 2012-2016. Until 2032-2036, the PAF is expected to rise in Denmark to 97% and in the Saarland to 92%. The demographic influence, on the other hand, is rather small.

CONCLUSIONS

More than 90% of all CM in Germany and Denmark are attributable to UVR exposure, and in principle, preventable. These findings underline the need for primary prevention strategies, aiming to increase the awareness of melanoma and its risk factors and to promote behavioural changes that decrease sun exposure.

Erythemal and vitamin D weighted solar UV dose-rates and doses estimated from measurements in mainland France and on Réunion Island

Solar UV radiation causes beneficial and detrimental changes in human health. International and national Health agencies recommend avoiding sun exposure when the solar rays are strongest (typically 2 h before and after solar noon). In this study we detail and refine such recommendations. We estimated biologically-effective radiation (inductive of erythema and pre-vitamin D) using spectral solar UV radiation measurements on a horizontal plane at three French sites equipped with spectroradiometers: Villeneuve d'Ascq (VDA) (North of France); Observatoire de Haute-Provence (OHP) (French Southern Alps); and Saint-Denis de La Réunion (SDR) on Réunion Island, in the Indian Ocean. These sites are very different: VDA is a semi-urban site in a flat region, OHP a rural mountainous site and SDR a coastal urban site on a small mountainous island. Biologically active radiation was analyzed by studying erythema induction and measuring pre-vitamin D synthesis. Dose-rates, doses and times for sunburn induction and vitamin D production were derived. Regarding the level of vitamin D dose considered here (1000 IU), we found that at mainland sites time required for vitamin D synthesis was relatively long, even around solar noon, in winter months this could be 2-3 h for phototype II individuals exposing their face and hands. In the tropics vitamin D could always be synthesized in a reasonable time (e.g. 20 min in winter). By contrast, in summer, the required duration times (exposing face, hands, arms and legs) are very short, approximately 2-4 min on the mainland and 1 min in the tropics for phototype II individuals. In all skin phototypes the duration of sun exposure required to induce erythema was generally longer than that to produce vitamin D. These quantitative results, obtained using an instrument measuring on a horizontal plane and with an unobstructed view, do not represent realistic values for human exposure. To account for realistic human body exposure, received doses and times of exposure were adjusted. Our study shows that, mostly in summer, the time periods where limited solar exposure is recommended should be extended, especially at low latitude locations.

Vitamin D and Skin Cancer: An Epidemiological, Patient-Centered Update and Review

BACKGROUND

The current vitamin D deficiency epidemic is accompanied by an increase in endemic skin cancer. There are still multiple controversies. This review aims to give practical recommendations regarding vitamin D among people at risk or with a personal history of skin cancer.

METHODS

Narrative review including human research articles published between 2011 and 2021, elaborated bearing in mind an epidemiological, patient-centered approach.

RESULTS

Ultraviolet (UV) exposure (neither artificial nor natural) is not the ideal source to synthesize vitamin D. There is conflicting epidemiological evidence regarding vitamin D, non-melanoma skin cancer (NMSC), and cutaneous melanoma (CMM), confounded by the effect of sun exposure and other factors.

CONCLUSIONS

Current evidence is controversial, and there are no widely applicable strategies. We propose three practical recommendations. Firstly, sun protection recommendations should be kept among people at risk or with a personal history of skin cancer. Secondly, vitamin D should preferably be sourced through diet. In patients with melanoma or at risk of cutaneous cancer, serum vitamin D checks are warranted to detect and avoid its insufficiency.

OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY FINDINGS IN TWO CASES OF SOLAR RETINOPATHY

PURPOSE

To report optical coherence tomography angiography findings obtained in two patients with solar retinopathy.

METHODS

Two case reports.

RESULTS

Two patients presented with blurry vision after sun gazing during the recent solar eclipse and were found to have characteristic foveal lesions on examination and optical coherence tomography consistent with solar retinopathy. Optical coherence tomography angiography showed a focal area of nonperfusion of the choriocapillaris in the affected eyes.

CONCLUSION

Changes to the choriocapillaris layer on optical coherence tomography angiography in two patients with solar retinopathy suggest that damage is not limited to the retina.

Sun Exposure and Black Skin

Black skin, compared with white skin, is generally assumed to be more resistant to the consequences of sun exposure due to its epidermal melanin content. However, recent scientific evidence shows that black skin is not completely impervious to sunlight. Both clinical and -experimental data have reported sun-induced effects on black skin. Black skin can warm, burn and peel when -exposed to the sun. Exposure to the sun can also cause hyperpigmentation and photoageing manifestations. The current misconceptions expressed by most black individuals about their resistance to sun-induced effects prevent their engagement in sun safe behaviours. Therefore, the demystification of the harmful effects of the sun needs to be supported by more research studies showing the effectiveness of sun protection strategies for the black population.

Sun exposure reduction by melanoma survivors with wearable sensor providing real-time UV exposure and daily text messages with structured goal setting

Despite knowledge of subsequent melanoma risk and the benefit of sun protection in risk reduction, melanoma survivors often do not engage in adequate sun protection and continue to sunburn at rates similar to individuals without a history of skin cancer. This novel intensive intervention provided a wearable UV sensor delivering real-time UV exposure with a smartphone and daily text messages. On days 1-10 (period 1), behavioral facilitation and outcome expectancies messages were provided. On day 10, participants reviewed and reflected on their daily UV exposure on the previous 10 days and set goals for improving sun protection. Then on days 11-21 (period 2) self-efficacy and self-regulation messages were provided. Sixty melanoma survivors were randomized (1:1) to receive structured or unstructured goal setting queries on day 10. Controlling for cloudy/rain conditions with less UV due to weather, there was a time effect with a significant decrease in UV exposure from periods 1-2 [period 1-2, F (59) = 22.60, p < 0.0001]. In this short-term study, melanoma survivors managed their daily UV exposure to stay below their maximum tolerated UV dose. ClinicalTrials.gov Protocol Record NCT0334796, date of registration Nov 15, 2017.

Comparative Toxicity Study of Novel Light-Activated Insecticide and Deltamethrin in Albino Rats

&lt;b&gt;Background and Objective:&lt;/b&gt; Tri-sodium Copper of chlorophyllins (Agri-Safe) is a novel biocide using recently to control the mosquitoes as a larvicide. Because, the lack of adequate data on the toxicity of this compound, more toxicological studies on this new compound are necessary. Therefore the study aimed to evaluate the adverse effects of this new insecticide and in comparison with the traditional insecticide Deltamethrin (DM). &lt;b&gt;Materials and Methods:&lt;/b&gt; Twenty-five adult male rats were randomly divided into five groups. The first group was kept in control. The second and third groups were administered at doses of 0.59 and 0.24 mg kg&lt;sup&gt;1&lt;/sup&gt; b.wt., of DM. The fourth and 5th groups were administrated at doses of 250 and 100 mg kg&lt;sup&gt;1&lt;/sup&gt; b.wt. of Agri-Safe respectively. The administrations were orally by gavage for 90 consecutive days. The rats were humanly sacrificed and whole blood was collected for hematological parameters and bone marrow was collected for mutagenicity assays. &lt;b&gt;Results:&lt;/b&gt; The estimated LD&lt;sub&gt;50&lt;/sub&gt; of DM and Agri-Safe were 11.76 and more than 5000 mg kg&lt;sup&gt;1&lt;/sup&gt; b.wt., respectively. Both insecticides induced slight hepatotoxicity but not nephrotoxicity. The high and low doses of DM induced prominent oxidative stress while Agri-Safe did not induce oxidative stress. The results of genotoxicity revealed that DM caused greater mutagenic effect at high and low doses, while Agri-Safe induced slight significant genotoxicity at high-dose only. &lt;b&gt;Conclusion:&lt;/b&gt; It can be concluded that Deltamethrin (DM) can induce oxidative stress and prominent genotoxicity while tri-sodium copper of chlorophyllins has a low side effect and its effect is due to copper elements.

A theoretical framework of the hybrid mechanism of photosystem II photodamage

Photodamage of photosystem II is a significant physiological process that is prevalent in the fields of photobiology, photosynthesis research and plant/algal stress. Since its discovery, numerous efforts have been devoted to determine the causes and mechanisms of action of photosystem II photodamage. There are two contrasting hypotheses to explain photodamage: (1) the excitation pressure induced by light absorption by the photosynthetic pigments and (2) direct photodamage of the Mn cluster located at the water-splitting site, which is independent of excitation pressure. While these two hypotheses seemed mutually exclusive, during the last decade, several independent works have proposed an alternative approach indicating that both hypotheses are valid. This was termed the dual hypothesis of photosystem II photodamage, and it postulates that both excess excitation and direct Mn photodamage operate at the same time, independently or in a synergic manner, depending on the type of sample, temperature, light spectrum, or other environmental stressors. In this mini-review, a brief summary of the contrasting hypotheses is presented, followed by recapitulation of key discoveries in the field of photosystem II photodamage of the last decade, and a synthesis of how these works support a full hybrid framework (operation of several mechanisms and their permutations) to explain PSII photodamage. All these are in recognition of Prof. Wah Soon Chow (the Australian National University), one of the key proposers of the dual hypothesis.

Photosynthesis on the edge: photoinhibition, desiccation and freezing tolerance of Antarctic bryophytes

In Antarctica, multiple stresses (low temperatures, drought and excessive irradiance) hamper photosynthesis even in summer. We hypothesize that controlled inactivation of PSII reaction centres, a mechanism widely studied by pioneer work of Fred Chow and co-workers, may effectively guarantee functional photosynthesis under these conditions. Thus, we analysed the energy partitioning through photosystems in response to temperature in 15 bryophyte species presenting different worldwide distributions but all growing in Livingston Island, under controlled and field conditions. We additionally tested their tolerance to desiccation and freezing and compared those with their capability for sexual reproduction in Antarctica (as a proxy to overall fitness). Under field conditions, when irradiance rules air temperature by the warming of shoots (up to 20 °C under sunny days), a predominance of sustained photoinhibition beyond dynamic heat dissipation was observed at low temperatures. Antarctic endemic and polar species showed the largest increases of photoinhibition at low temperatures. On the contrary, the variation of thermal dissipation with temperature was not linked to species distribution. Instead, maximum non-photochemical quenching at 20 °C was related (strongly and positively) with desiccation tolerance, which also correlated with fertility in Antarctica, but not with freezing tolerance. Although all the analysed species tolerated - 20 °C when dry, the tolerance to freezing in hydrated state ranged from the exceptional ability of Schistidium rivulare (that survived for 14 months at - 80 °C) to the susceptibility of Bryum pseudotriquetrum (that died after 1 day at - 20 °C unless being desiccated before freezing).

The effect of different spectral light quality on the photoinhibition of Photosystem I in intact leaves

Light energy causes damage to Photosystem I (PSI) and Photosystem II (PSII). The majority of the previous photoinhibition studies have been conducted with PSII, which shows much larger photoinhibition than PSI; therefore, relatively little is known about the mechanism of PSI photoinhibition so far. A previous report showed that the photoinhibition action spectrum measured with PSI activity of isolated thylakoid is similar to the absorption spectrum of chlorophyll. However, it is known that the extent of PSI photoinhibition is much smaller in vivo compared to in vitro. It is also possible that the different extent of PSII photoinhibition, caused by different spectral light qualities, can affect the photoinhibition of PSI in vivo because PSI receives electrons from PSII. In the present research, to study the effect of light quality and the effect of the extent of PSII photoinhibition on the PSI photoinhibition in vivo, intact leaves were photoinhibited under four different light qualities. The rate coefficient of PSI photoinhibition was significantly higher in blue and red light compared to white light. The rate of PSI photoinhibition at the same photon-exposure was the largest in blue and red light and followed by white and green light. These results support the notion that light absorption by chlorophyll is responsible for the PSI photoinhibition, even in intact leaves. The variation among light colors in the relationships between the extent of photoinhibition of PSII and that of PSI indicate that PSI and PSII are independently photoinhibited with different mechanisms in the early stage of in vivo photoinhibition.

Photosystem I in low light-grown leaves of Alocasia odora, a shade-tolerant plant, is resistant to fluctuating light-induced photoinhibition

When intact green leaves are exposed to the fluctuating light, in which high light (HL) and low light (LL) alternate, photosystem I (PSI) is readily damaged. This PSI inhibition is mostly alleviated by the addition of far-red (FR) light. Here, we grew Alocasia odora, a shade-tolerant species, at several light levels and examined their photosynthetic traits in relation to the fluctuating light-induced PSI inhibition. We found that, even in the absence of FR, PSI in LL-grown leaves was resistant to the fluctuating light. LL leaves showed higher chlorophyll (Chl) contents on leaf area basis, lower Chl a/b ratios, lower cytochrome f/P700 ratios, and lower PSII/PSI excitation ratios assessed by the 77 K fluorescence. Also, P700 in the HL phase of the fluctuating light was more oxidized. The results of the regression analyses of the PSI photoinhibition to these traits indicate that the lower electron flow rate to P700 and more excitation energy transfer to PSI protect PSI in LL-grown leaves. Both of these contribute oxidization of P700 to the efficient quencher form P700⁺. These features may be common in LL-grown shade-tolerant species, which are often exposed to strong sunflecks in their natural habitats.

Do rapid photosynthetic responses protect maize leaves against photoinhibition under fluctuating light?

Plants in their natural environment are often exposed to fluctuating light because of self-shading and cloud movements. As changing frequency is a key characteristic of fluctuating light, we speculated that rapid light fluctuation may induce rapid photosynthetic responses, which may protect leaves against photoinhibition. To test this hypothesis, maize seedlings were grown under fluctuating light with various frequencies (1, 10, and 100 cycles of fluctuations/10 h), and changes in growth, chlorophyll content, gas exchange, chlorophyll a fluorescence, and P700 were analyzed carefully. Our data show that though the growth and light-saturated photosynthetic rate were depressed by rapidly fluctuating light, photosynthesis induction was clearly speeded up. Furthermore, more rapid fluctuation of light strikingly reduced the chlorophyll content, while thermal dissipation was triggered and enhanced. The chlorophyll a fluorescence induction kinetics and P700 absorption results showed that the activities of both photosystem II and photosystem I decreased as the frequency of the fluctuating light increased. In all treatments, the light intensities of the fluctuating light were kept constant. Therefore, rapid light fluctuation frequency itself induced the acceleration of photosynthetic induction and the enhancement of photoprotection in maize seedlings, which play important roles in protecting photosynthetic apparatus against fluctuating high light to a certain extent.

The major photoprotective role of anthocyanins in leaves of Arabidopsis thaliana under long-term high light treatment: antioxidant or light attenuator?

Anthocyanins are water-soluble pigments in plants known for their photoprotective role against photoinhibitory and photooxidative damage under high light (HL). However, it remains unclear whether light-shielding or antioxidant activity plays a major role in the photoprotection exerted by anthocyanins under HL stress. To shed light on this question, we analyzed the physiological and biochemical responses to HL of three Arabidopsis thaliana lines (Col, chi, ans) with different light absorption and antioxidant characteristics. Under HL, ans had the highest antioxidant capacity, followed by Col, and finally chi; Col had the strongest light attenuation capacity, followed by chi, and finally ans. The line ans had weaker physiological activity of chloroplasts and more severe oxidative damage than chi after HL treatment. Col with highest photoprotection of light absorption capacity had highest resistance to HL among the three lines. The line ans with high antioxidant capacity could not compensate for its disadvantages in HL caused by the absence of the light-shielding function of anthocyanins. In addition, the expression level of the Anthocyanin Synthase (ANS) gene was most upregulated after HL treatment, suggesting that the conversion of colorless into colored anthocyanin precursors was necessary under HL. The contribution of anthocyanins to flavonoids, phenols, and antioxidant capacity increased in the late period of HL, suggesting that plants prefer to synthesize red anthocyanins (a group of colored antioxidants) over other colorless antioxidants to cope with HL. These experimental observations indicate that the light attenuation role of anthocyanins is more important than their antioxidant role in photoprotection.

The relationship between anthocyanin accumulation and photoprotection in young leaves of two dominant tree species in subtropical forests in different seasons

Increasing amounts of experimental evidence show that anthocyanins provide physiological protection to plants under stress. However, the difference in photoprotection mediated by anthocyanins and other photoprotective substances in different seasons is still uncertain. To determine the relationship between anthocyanin accumulation and the photoprotective effects in different seasons, Castanopsis chinensis and Acmena acuminatissima, whose anthocyanin accumulation patterns differ in different seasons, were used as materials to explain how plants adapt to different seasons; as such, their physiological and biochemical responses were analyzed. Young leaves of C. chinensis and A. acuminatissima presented different colors in the different seasons. In summer, the young leaves of C. chinensis were purplish red, while those of A. acuminatissima were light green. In winter, the young leaves of C. chinensis were light green, while those of A. acuminatissima were red. Compared with the young red leaves, the young light green leaves that did not accumulate anthocyanins had higher flavonoid and phenolics contents, total antioxidant capacity, non-photochemical quenching (NPQ), and relative membrane leakage, and a slower recovery rate in the maximum photochemical efficiency (F_v/F_m) after high-light treatment. In addition, the net photosynthesis rate (P_n), transpiration rate (T_r), stomatal conductance (g_s), and the effective quantum yield of PSII (Φ_PSII) of the young leaves in winter were significantly lower than those in summer, while the activities of catalase (CAT, EC 1.11.1.6), peroxidase (POD, EC 1.11.1.7), and superoxide dismutase (SOD, EC 1.15.1.1) were significantly higher than those in summer. These data indicate that to adapt to seasonal changes anthocyanins, other antioxidative substances and antioxidative enzymes, as well as components involved in the safe dissipation of excitation energy as heat need to cooperate with one another.

Mehler reaction plays a role in C3 and C4 photosynthesis under shade and low CO2

Alternative electron fluxes such as the cyclic electron flux (CEF) around photosystem I (PSI) and Mehler reaction (Me) are essential for efficient photosynthesis because they generate additional ATP and protect both photosystems against photoinhibition. The capacity for Me can be estimated by measuring O₂ exchange rate under varying irradiance and CO₂ concentration. In this study, mass spectrometric measurements of O₂ exchange were made using leaves of representative species of C₃ and C₄ grasses grown under natural light (control; PAR ~ 800 µmol quanta m^-2 s^-1) and shade (~ 300 µmol quanta m^-2 s^-1), and in representative species of gymnosperm, liverwort and fern grown under natural light. For all control grown plants measured at high CO₂, O₂ uptake rates were similar between the light and dark, and the ratio of Rubisco oxygenation to carboxylation (V_o/V_c) was low, which suggests little potential for Me, and that O₂ uptake was mainly due to photorespiration or mitochondrial respiration under these conditions. Low CO₂ stimulated O₂ uptake in the light, V_o/V_c and Me in all species. The C₃ species had similar V_o/V_c, but Me was highest in the grass and lowest in the fern. Among the C₄ grasses, shade increased O₂ uptake in the light, V_o/V_c and the assimilation quotient (AQ), particularly at low CO₂, whilst Me was only substantial at low CO₂ where it may contribute 20-50% of maximum electron flow under high light.

The Impacts of Sun Exposure on Worker Physiology and Cognition: Multi-Country Evidence and Interventions

BACKGROUND

A set of four case-control (n = 109), randomized-controlled (n = 7), cross-sectional (n = 78), and intervention (n = 47) studies was conducted across three countries to investigate the effects of sun exposure on worker physiology and cognition.

METHODS

Physiological, subjective, and cognitive performance data were collected from people working in ambient conditions characterized by the same thermal stress but different solar radiation levels.

RESULTS

People working under the sun were more likely to experience dizziness, weakness, and other symptoms of heat strain. These clinical impacts of sun exposure were not accompanied by changes in core body temperature but, instead, were linked with changes in skin temperature. Other physiological responses (heart rate, skin blood flow, and sweat rate) were also increased during sun exposure, while attention and vigilance were reduced by 45% and 67%, respectively, compared to exposure to a similar thermal stress without sunlight. Light-colored clothes reduced workers' skin temperature by 12-13% compared to darker-colored clothes.

CONCLUSIONS

Working under the sun worsens the physiological heat strain experienced and compromises cognitive function, even when the level of heat stress is thought to be the same as being in the shade. Wearing light-colored clothes can limit the physiological heat strain experienced by the body.

Sun Protection Outreach Teaching by Students (SPOTS)-Evaluating the Efficacy of Skin Cancer Prevention Education for Adolescents

BACKGROUND

The Sun Protection Outreach Teaching by Students (SPOTS) program addresses an unmet need by training medical students to teach adolescents about skin cancer prevention and early detection.

OBJECTIVE

To measure (1) changes in adolescents' knowledge, attitudes, and behaviors regarding sun protection and (2) the impact on medical students' confidence in skin cancer preventive counseling.

METHODS

Pre-SPOTS and 1-month post-SPOTS program surveys were completed by adolescent participants and medical student instructors.

RESULTS

Amongst adolescent students, analysis of 1,142 pre-program surveys and 618 post-program surveys revealed statistically significant improvements in knowledge, attitudes, and behaviors. Among the favorable results, 26%, 41%, and 20% improvements over baseline were observed in SPF knowledge, preference for natural untanned skin, and intent to wear sunscreen, respectively (p < .001). One-third of adolescents reported having tried to increase sunscreen use. Amongst medical students, analysis of 78 pre-teaching and 74 post-teaching surveys revealed an increase in feeling "very confident" in counseling patients, from 23% pre-teaching to 82% post-teaching (p < .001).

CONCLUSION

SPOTS demonstrated a dual benefit to adolescents and medical students. The program is available for dermatologists to implement in their communities.

Sunlight-induced Painful Skin (Sun Pain): A New Differential Diagnosis in Photodermatology

Photodermatoses are characterized by the development of skin eruptions following exposure to ultraviolet radiation or visible light. We report here the clinical findings and results of laboratory investigations and phototesting of 6 patients who experience debilitating and excruciating pain after sun exposure ("sun pain") in the absence of any skin eruption. Phototesting with sub-erythemal doses of ultraviolet A radiation triggered localized pain in 4 patients. At follow-up, 3 female patients were found to have developed fibromyalgia, 2 male patients experienced a major depressive disorder, and another male patient had a conversion disorder. One patient also developed allodynia to tactile stimuli and one developed allodynia to thermal and tactile stimuli. Psychiatric conditions should be taken into consideration in patients presenting with excruciating and debilitating pain on exposure to ultraviolet radiation, but with absence of skin eruption. Further research is needed to evaluate whether it represents a type of allodynia triggered by exposure to ultraviolet radiation.