The influence of the amount of sunscreen applied and its sun protection factor (SPF): evaluation of two sunscreens including the same ingredients at different concentrations

Background To estimate labeled sun protection factor (SPF) for sunscreen, the amount of product applied on volunteers, according to food and drug administration (FDA) and International protocols, is 2 mg/cm(2). However, different studies have shown that consumers actually apply much less product when exposed to the sun. Previous studies have reported contradictory findings in an attempt to correlate the amount applied in relation to SPF. The objective of the present study was to estimate the influence of the quantity of sunscreen applied in the determination of SPF, according to the FDA methodology. Subjects and methods Forty volunteers were included in two groups (SPF 15 and 30). The selected sunscreen was then applied in four different quantities (2, 1.5, 1.0 and 0.5 mg/cm(2)). All areas were irradiated with a solar simulator. After 24 h, the minimal erythemal dose (MED) and SPF were determined. Results In both groups, we observed that the SPF decreased when the amount of sunscreen applied was decreased. The differences between the 2 mg/cm(2) area and the others were significant in both groups (P < 0.001). The correlation between specified SPF and applied amount grew exponentially. Conclusion The protection provided by sunscreen is related to the amount of product applied. It is essential to educate consumers to apply larger amounts of sunscreen for adequate photoprotection.

Effects of long-term chronic exposure to sun radiation in immunological system of commercial fishermen in Recife, Brazil

BACKGROUND: Among the various occupations which necessarily require long-term and chronic sun exposure is that of a fisherman. However, clinical experience in dermatology earned over several years of medical practice does not seem to confirm this hypothesis. OBJECTIVE: To evaluate clinical, histological and immunological effects of long-term and chronic exposure to ultraviolet radiation in fishermen. METHODS: A prospective, cross-sectional and observational study characterized skin lesions, immunological markers and histological alterations in fishermen, as well as lymphocyte subpopulations compared to a control group. Mann-Whitney, Fisher`s and Wilcoxon statistical tests were used at a significance level of 0.05. RESULTS: There were significant differences between the exposed group and the group protected due to elastosis (p = 0.03), ectasia of dermal vessels (p = 0.012) and number of cells in the epidermal layers between cones (p = 0.029). Most common among fishermen were CD45RO, CD68 + and mastocytes in the skin (p = 0.040, p < 0.001, p = 0.001) and CD3CD8CD45RO in the blood (p = 0.016). CONCLUSION: The alterations suggest that long-term and chronic sun exposure promotes tolerance to ultraviolet radiation, which protects against immunosuppression.

Vitamin D status in a sunny country: Where has the sun gone?

Background & aims: Hypovitaminosis D [serum 25 vitamin D < 30 ng/ml] is related to the development of metabolic bone disease and greater risk of chronic illnesses. However, it is frequently under-diagnosed, mainly in countries where UV radiation is abundant. We prospectively determined the prevalence and the predictors of serum 25 vitamin D (s25(OH)D) in a healthy Brazilian population after the winter and after the summer. Methods: 603 (118M and 485F) healthy Brazilian volunteers aged 18-90 years from a universitary hospital were selected after the winter of 2006. From the initial sample, 209 volunteers (31M and 178F) accepted to participate in a second health check after the subsequent summer. Results: After the winter, median s25(OH)D was 21.4 ng/mL and 77.4% of the population presented hypovitaminosis D. s25(OH)D was significantly related to age, BMI, PTH and race. In multivariate linear regression analysis, s25(OH)D was significantly and independently dependent on age, glycemia and skin color. Significant increase in s25(OH)D was verified after summer [10.6 (3.7-19.3 ng/ml); p < 0.001] and this improvement was dependent on age. We also observed a significant decrease in hyperparathyroidism prevalence (20.8% vs. 4.9%; P < 0.0001). Conclusion: In Sao Paulo, at the end of winter, we observed a high prevalence of hypovitaminosis D and secondary hyperparathyroidism in healthy adults. s25(OH)D was dependent on age and skin color. After summer, we observed a decrease in the prevalence of hypovitaminosis D. This unexpected finding emphasizes the need for a strong recommendation to monitor s25(OH)D, even in a sunny country such as Brazil. (C) 2010 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Sun exposure and interaction with family history in risk of melanoma, Queensland, Australia

Sun exposure is the main environmental risk factor for melanoma, but the timing of exposure during life that confers increased risk is controversial. Here we provide the first report of the association between lifetime and age-specific cumulative ultraviolet exposure and cutaneous melanoma in Queensland, Australia, an area of high solar radiation, and examine the association separately for families at high, intermediate and low familial melanoma risk. Subjects were a population-based sample of melanoma cases diagnosed and registered in Queensland between 1982 and 1990 and their relatives. The analysis included 1,263 cases and relatives with confirmed cutaneous melanoma and 3,111 first-degree relatives without melanoma as controls. Data an lifetime residence and sun exposure, family history and other melanoma risk factors were collected by a mailed questionnaire. Using conditional multiple logistic regression with stratification by family, cumulative sun exposure in childhood and in adulthood after age 20 was significantly associated with melanoma, with estimated relative risks of 1.15 per 5,000 minimal erythemal doses (MEDs) from age 5 to 12 years, and 1.52 per 5 MEDs/day from age 20. There was no association with sun exposure in families at high familial melanoma risk. History of nonmelanoma skin cancer (relative risk [RR] = 1.26) and multiple sunburns (RR = 1.31) were significant risk factors. These findings indicate that sun exposure in childhood and in adulthood are important determinants of melanoma but not in those rare families with high melanoma susceptibility, in which genetic factors are likely to be more important. (C) 2002 Wiley-Liss, Inc.

Behaviour of caregivers to protect their infants from exposure to the sun in Queensland, Australia.

Exposure to the sun by infants has been demonstrated to increase the risk of the development of melanoma and other skin cancers later in life. A cohort of 508 women who delivered healthy Caucasian babies were followed up at 1 year to determine their knowledge, attitudes and practices regarding sun protection towards themselves and their child. In addition, the 1-year-old infants were assessed by a trained nurse for the number of nevi they had on their skin. Results indicate caregivers reported a high level of sun-protection practices towards their child, with 93% of the caregivers reporting usually or always placing the child in the shade when going outside. Further, 81% of the caregivers reported usually or always placing a hat on the child, while 64% reported usually or always applying sunscreen to the child's exposed skin. Interestingly, only 61% of the caregivers reported that they stayed in the shade to reduce sun exposure and only 42% wore a hat when out in the sun. Mother's own personal sun-protection methods predicted the method of sun protection that she would most likely use for the child. While children appear to be reasonably protected from the sun, they are influenced by their mother's own behaviors.

Environmental conditions and variation in levels of sun exposure among children in child care

Sun exposure in childhood is I of the risk factors for developing skin cancer, yet little is known about levels of exposure at this age. This is particularly important in countries with high levels of ultraviolet radiation. (UVR) such as Australia. Among 49 children 3 to 5 years of age attending child care centers, UVR exposure was studied under 4 conditions in a repeated measures design; sunny days, cloudy days, teacher's instruction to stay in the shade, and a health professionals instruction to apply sunscreen. Three different data collection methods were employed: (a) completion of questionnaire or diary by parents and researcher, (b) polysulphone dosimeter readings, and (c) observational audits (video recording). Results of this study indicated that more than half the children had been sunburnt (pink or red) and more than a third had experienced painful sunburn (sore or tender) in the last summer. Most wore short sleeve shirts, short skirts or shorts and cap, that do not provide optimal levels of skin protection. However, sunscreen was applied to all exposed parts before the children went out to the playground. Over the period of I hr (9-10 a.m.) the average amount of time children spent in full sun was 22 min. On sunny days there was more variation across children in the amount of sun exposure received. While the potential amount of UVR exposure for young children during the hour they were outside on a sunny day was 1.45 MED (Minimum Erythemal Dose), they received on average 0.35 MED, which is an insufficient amount to result in an erythemal response on fair skin even without the use of sunscreen.

O casamento real de William e Kate : a cobertura jornalística nos jornais The Daily Mail, The Guardian e The Sun

Dissertação apresentada à Escola Superior de Comunicação Social como parte dos requisitos para obtenção de grau de mestre em Jornalismo.

Modelling Amazonian forest eddy covariance data: a comparison of big leaf versus sun/shade models for the C-14 tower at Manaus I. Canopy photosynthesis

In this study, we concentrate on modelling gross primary productivity using two simple approaches to simulate canopy photosynthesis: "big leaf" and "sun/shade" models. Two approaches for calibration are used: scaling up of canopy photosynthetic parameters from the leaf to the canopy level and fitting canopy biochemistry to eddy covariance fluxes. Validation of the models is achieved by using eddy covariance data from the LBA site C14. Comparing the performance of both models we conclude that numerically (in terms of goodness of fit) and qualitatively, (in terms of residual response to different environmental variables) sun/shade does a better job. Compared to the sun/shade model, the big leaf model shows a lower goodness of fit and fails to respond to variations in the diffuse fraction, also having skewed responses to temperature and VPD. The separate treatment of sun and shade leaves in combination with the separation of the incoming light into direct beam and diffuse make sun/shade a strong modelling tool that catches more of the observed variability in canopy fluxes as measured by eddy covariance. In conclusion, the sun/shade approach is a relatively simple and effective tool for modelling photosynthetic carbon uptake that could be easily included in many terrestrial carbon models.

Caracteres morfométricos en Difflugia corona (Testacea, Difflugidae) en ambientes lénticos del Chaco, Argentina

Morphometric characters of two populations of Difflugia corona Wallich, 1864 collected in two climatic stations (Spring, Autumn) in lentic environments of Chaco Province, Argentina, are studied. In the first climatic station it was registered specimens of bigger size; in the second, the size of the individuals was very below the minimum values registered. It is suggested a possible relationship between the size of the organisms and the availability of the inhabitable vegetable substratum.

The Ponca sun dance, by George A. Dorsey.

v.7:no.2(1905)

The Arapaho sun dance : the ceremony of the Offerings lodge / by George A. Dorsey.

v.4(1903)

Real rank zero algebras have the corona factorization property

The purpose of this short note is to prove that a stable separable C*-algebra with real rank zero has the so-called corona factorization property, that is, all the full multiplier projections are properly in finite. Enroute to our result, we consider conditions under which a real rank zero C*-algebra admits an injection of the compact operators (a question already considered in [21]).