Dataset Information

The mathematics of tanning.

ABSTRACT:

Background

The pigment melanin is produced by specialized cells, called melanocytes. In healthy skin, melanocytes are sparsely spread among the other cell types in the basal layer of the epidermis. Sun tanning results from an UV-induced increase in the release of melanin to neighbouring keratinocytes, the major cell type component of the epidermis as well as redistribution of melanin among these cells. Here we provide a mathematical conceptualization of our current knowledge of the tanning response, in terms of a dynamic model. The resolution level of the model is tuned to available data, and its primary focus is to describe the tanning response following UV exposure.

Results

The model appears capable of accounting for available experimental data on the tanning response in different skin and photo types. It predicts that the thickness of the epidermal layer and how far the melanocyte dendrites grow out in the epidermal layers after UV exposure influence the tanning response substantially.

Conclusion

Despite the paucity of experimental validation data the model is constrained enough to serve as a foundation for the establishment of a theoretical-experimental research programme aimed at elucidating the more fine-grained regulatory anatomy underlying the tanning response.

SUBMITTER: Thingnes J

PROVIDER: S-EPMC2714304 | biostudies-literature | 2009 Jun

REPOSITORIES: biostudies-literature

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Publications

The mathematics of tanning.

Thingnes Josef J Oyehaug Leiv L Hovig Eivind E Omholt Stig W SW

BMC systems biology 20090609

<h4>Background</h4>The pigment melanin is produced by specialized cells, called melanocytes. In healthy skin, melanocytes are sparsely spread among the other cell types in the basal layer of the epidermis. Sun tanning results from an UV-induced increase in the release of melanin to neighbouring keratinocytes, the major cell type component of the epidermis as well as redistribution of melanin among these cells. Here we provide a mathematical conceptualization of our current knowledge of the tanni ...[more]

PMID: 19505344

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Project description:ImportanceThe US Food and Drug Administration has classified tanning beds as carcinogenic. Most states have enacted legislation to prevent or create barriers for minors accessing tanning establishments. Determining tanning salon compliance with legislation would provide an indication of the influence of legislation at preventing exposure to the carcinogen in minors.ObjectivesTo investigate compliance rates in the 42 states and the District of Columbia with legislation restricting tanning bed use in minors and to identify differences in compliance based on population, regional location, salon ownership, age group being regulated, and time since the law was enacted.Design, setting, and participantsThis investigation was a cross-sectional telephone survey conducted between February 1, 2015, and April 30, 2016, by callers posing as minors attempting to schedule a tanning appointment. The setting was tanning salons in the 42 states and the District of Columbia that currently have legislation restricting tanning bed use in minors. Included in the study were 427 tanning salons, 10 randomly selected from each state or territory with tanning legislation.Main outcomes and measuresOverall compliance of tanning salons with state tanning legislation and differences in compliance based on community population, regional location, independent vs chain tanning salon, age group being regulated, and time since the law was enacted.ResultsOf the 427 tanning salons surveyed, overall noncompliance with state legislation was 37.2% (n = 159). There were more noncompliant tanning salons in rural locations (45.5%; 95% CI, 37.5%-53.7%; P = .009), southern regions of the United States (49.4%; 95% CI, 41.4%-57.4%; P = .001), independently owned salons (43.9%; 95% CI, 37.3%-50.6%; P = .003), states with younger age groups being regulated (53.5%; 95% CI, 45.7%-61.2%; P < .001), and states with more than one tanning regulation (50.0%; 95% CI, 42.0%-58.0%; P < .001). No difference was found based on time since the law was enacted.Conclusions and relevanceCompliance with state legislation aimed at limiting tanning bed use among US minors is unsatisfactory, indicating that additional efforts to enforce the laws and education of the harmful effects of UV tanning are necessary, especially in rural, independently owned, and tanning salons in southern regions, which have decreased compliance rates.

Project description:ObjectiveTo assess whether an association exists between financial links to the indoor tanning industry and conclusions of indoor tanning literature.DesignSystematic review.Data sourcesPubMed, Embase, and Web of Science, up to 15 February 2019.Study selection criteriaArticles discussing indoor tanning and health were eligible for inclusion, with no article type restrictions (original research, systematic reviews, review articles, case reports, editorials, commentaries, and letters were all eligible). Basic science studies, articles describing only indoor tanning prevalence, non-English articles, and articles without full text available were excluded.Results691 articles were included in analysis, including empiric articles (eg, original articles or systematic reviews) (357/691; 51.7%) and non-empiric articles letters (eg, commentaries, letters, or editorials) (334/691; 48.3%). Overall, 7.2% (50/691) of articles had financial links to the indoor tanning industry; 10.7% (74/691) articles favored indoor tanning, 3.9% (27/691) were neutral, and 85.4% (590/691) were critical of indoor tanning. Among the articles without industry funding, 4.4% (27/620) favored indoor tanning, 3.5% (22/620) were neutral, and 92.1% (571/620) were critical of indoor tanning. Among the articles with financial links to the indoor tanning industry, 78% (39/50) favored indoor tanning, 10% (5/50) were neutral, and 12% (6/50) were critical of indoor tanning. Support from the indoor tanning industry was significantly associated with favoring indoor tanning (risk ratio 14.3, 95% confidence interval 10.0 to 20.4).ConclusionsAlthough most articles in the indoor tanning literature are independent of industry funding, articles with financial links to the indoor tanning industry are more likely to favor indoor tanning. Public health practitioners and researchers need to be aware of and account for industry funding when interpreting the evidence related to indoor tanning.Systematic review registrationPROSPERO CRD42019123617.

Project description:BackgroundMathematics anxiety (MA), a state of discomfort associated with performing mathematical tasks, is thought to affect a notable proportion of the school age population. Some research has indicated that MA negatively affects mathematics performance and that girls may report higher levels of MA than boys. On the other hand some research has indicated that boys' mathematics performance is more negatively affected by MA than girls' performance is. The aim of the current study was to measure girls' and boys' mathematics performance as well as their levels of MA while controlling for test anxiety (TA) a construct related to MA but which is typically not controlled for in MA studies.MethodsFour-hundred and thirty three British secondary school children in school years 7, 8 and 10 completed customised mental mathematics tests and MA and TA questionnaires.ResultsNo gender differences emerged for mathematics performance but levels of MA and TA were higher for girls than for boys. Girls and boys showed a positive correlation between MA and TA and a negative correlation between MA and mathematics performance. TA was also negatively correlated with mathematics performance, but this relationship was stronger for girls than for boys. When controlling for TA, the negative correlation between MA and performance remained for girls only. Regression analyses revealed that MA was a significant predictor of performance for girls but not for boys.ConclusionsOur study has revealed that secondary school children experience MA. Importantly, we controlled for TA which is typically not controlled for in MA studies. Girls showed higher levels of MA than boys and high levels of MA were related to poorer levels of mathematics performance. As well as potentially having a detrimental effect on 'online' mathematics performance, past research has shown that high levels of MA can have negative consequences for later mathematics education. Therefore MA warrants attention in the mathematics classroom, particularly because there is evidence that MA develops during the primary school years. Furthermore, our study showed no gender difference in mathematics performance, despite girls reporting higher levels of MA. These results might suggest that girls may have had the potential to perform better than boys in mathematics however their performance may have been attenuated by their higher levels of MA. Longitudinal research is needed to investigate the development of MA and its effect on mathematics performance.

Dataset Information

The mathematics of tanning.

Background

Results

Conclusion

Publications

The mathematics of tanning.

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