Sun tanning

Abstract: UV light brings the world interesting effects in different areas of human life, such as entertainment, medical applications, and scientific research. Some examples of daily UVlight usage are: television, varieties of lamps, photolithography, sterilization, fluorescence, and even the sun tanning of human skin. However, its evil side is that it can cause serious damages to both people and materials. It produces DNA damage, [1] immune suppression [2] and skin photoaging. [3] It is also responsible for the decomposition and degradation of organic compounds including plastics, polymers, dyes, pigments, wood, paper, etc. These materials compose most of the articles in human life, such as artwork, furniture, buildings, vehicles, tools, decoration articles, etc. The energy of the photons of UV light is sufficiently high to break chemical bonds in these materials, which undergo a rapid photolytic and photo-oxidative reaction, resulting in weathering, discoloration, yellowing, bleaching, darkening, the loss of mechanical properties and gloss, etc. [4] Therefore, not only the usage of UV light, but also the protection against UV irradiation damage are of a great interest for ordinary people, scientists and industries.

Abstract: Objective: Using the terror management health model (J. L. Goldenberg & J. Arndt, 2008), the authors examined tanning outcomes as a function of priming tanning-relevant standards for attractiveness after reminders of death. Design: Study 1 consisted of 101 female college students recruited from a midwestern university; Study 2 consisted of 53 female participants recruited from a beach in south Florida. In both experiments, participants answered questions about their mortality or a control topic, and were presented with a fashion article that highlighted either the attractiveness of tanned (just in Study 1), pale, or natural-looking skin. Main Outcome Measures: Self-reported suntan intentions (Study 1) and sunscreen intentions (Study 2). Study 2 also assessed participants' interest in various sun protection products. Results and Conclusions: Study 1 demonstrated that mortality salience led to higher tanning intentions when the association between tanned skin and physical attractiveness was made salient and reduced intentions when the attractiveness of paler skin was highlighted. In Study 2, beachgoers, after reminders of death, reported greater preference for high sun protection sunscreen after reading an article about the attractiveness of paler skin tones. These findings contribute to an emerging understanding of how mortality concerns can influence health-related judgment and behavior.

Abstract: The skin is armored with "dead cells", the stratum corneum, and is continuously exposed to external stressful environments, such as atmospheric oxygen, solar radiations, and thermal and chemical insults. Melanocytes of neural crest origin are located in the skin, eye, inner ear, and leptomeninges. Melanin pigment in the skin is produced by melanocytes under the influence of various endogenous factors, derived from neighboring keratinocytes and underlying fibroblasts. The differentiation and functions of melanocytes are regulated at multiple processes, including transcription, RNA editing, melanin synthesis, and the transport of melanosomes to keratinocytes. Impairment at each step causes the pigmentary disorders in humans, with the historical example of oculocutaneous albinism. Moreover, heterozygous mutations in the gene coding for microphthalmia-associated transcription factor, a key regulator for melanocyte development, are associated with Waardenburg syndrome type 2, an auditory-pigmentary disorder. Sun tanning, melasma, aging spots (lentigo senilis), hair graying, and melanoma are well-known melanocyte-related pathologies. Melanocytes therefore have attracted much attention of many ladies, makeup artists and molecular biologists. More recently, we have shown that lipocalin-type prostaglandin D synthase (L-PGDS) is expressed in melanocytes but not in other skin cell types. L-PGDS generates prostaglandin D2 and also functions as an inter-cellular carrier protein for lipophilic ligands, such as bilirubin and thyroid hormones. Thus, melanocytes may exert hitherto unknown functions through L-PGDS and prostaglandin D2. Here we update the neuroendocrine functions of melanocytes and discuss the possible involvement of melanocytes in the control of the central chemosensor that generates respiratory rhythm.