The increase in reports of novel diseases in a wide range of ecosystems, both terrestrial and marine, has been linked to many factors including exposure to novel pathogens and changes in the global climate. Prevalence of skin cancer in particular has been found to be increasing in humans, but has not been reported in wild fish before. Here we report extensive melanosis and melanoma (skin cancer) in wild populations of an iconic, commercially-important marine fish, the coral trout Plectropomus leopardus. The syndrome reported here has strong similarities to previous studies associated with UV induced melanomas in the well-established laboratory fish model Xiphophorus. Relatively high prevalence rates of this syndrome (15%) were recorded at two offshore sites in the Great Barrier Reef Marine Park (GBRMP). In the absence of microbial pathogens and given the strong similarities to the UV-induced melanomas, we conclude that the likely cause was environmental exposure to UV radiation. Further studies are needed to establish the large scale distribution of the syndrome and confirm that the lesions reported here are the same as the melanoma in Xiphophorus, by assessing mutation of the EGFR gene, Xmrk. Furthermore, research on the potential links of this syndrome to increases in UV radiation from stratospheric ozone depletion needs to be completed.
Highly efficient room-temperature ultraviolet (UV) luminescence is obtained in heterostructures consisting of 10-nm-thick ultrathin ZnO films grown on Si nanopillars fabricated using self-assembled silver nanoislands as a natural metal nanomask during a subsequent dry etching process. Atomic layer deposition was applied for depositing the ZnO films on the Si nanopillars under an ambient temperature of 200°C. Based on measurements of photoluminescence (PL), an intensive UV emission corresponding to free-exciton recombination (approximately 3.31 eV) was observed with a nearly complete suppression of the defect-associated, broad-range visible emission peak. As compared to the ZnO/Si substrate, the almost five-times-of-magnitude enhancement in the intensity of PL, which peaked around 3.31 eV in the present ultrathin ZnO/Si nanopillars, is presumably attributed to the high surface/volume ratio inherent to the Si nanopillars. This allowed considerably more amount of ZnO material to be grown on the template and led to markedly more efficient intrinsic emission.
Sunscreens protect the skin against erythemal radiation (Eer). But at the same time they reduce the effective radiation dose (EVD) responsible for the formation of previtamin D in the skin. The paper describes a calculation method for optimizing the ratio EVD/Eer behind sunscreens e.g. with SPF 5, 15 and 30 respectively. Taking into account that a majority of people in industrialized countries suffer from a shortage in vitamin D even in summer time, the ratio Evd/Eer is a new and important criterion for the quality of sunscreens. Furthermore the exposure time tvd needed per day for forming the equivalent of the recommended amount of 2000 IU of vitamin D per day for skin type 2 is estimated when sunscreens with different filter compositions are used. In vitro experiments show a significant increase of the conversion of 7-dehydrocholesterol (7-DHC) to previtamin D when exposed to artificial solar radiation behind an experimental sunscreen optimized for previtamin D production compared to a commercial sunscreen having the same SPF.
In this study, zinc oxide (ZnO) nanorod arrays were synthesized using a simple hydrothermal reaction on ZnO seeds/n-silicon substrate. Several parameters were studied, including the heat-treatment temperature to produce ZnO seeds, zinc nitrate concentration, pH of hydrothermal reaction solution, and hydrothermal reaction time. The optimum heat-treatment temperature to produce uniform nanosized ZnO seeds was 400°C. The nanorod dimensions depended on the hydrothermal reaction parameters. The optimum hydrothermal reaction parameters to produce blunt tip-like nanorods (770 nm long and 80 nm in top diameter) were 0.1 M zinc nitrate, pH 7, and 4 h of growth duration. Phase analysis studies showed that all ZnO nanorods exhibited a strong (002) peak. Thus, the ZnO nanorods grew in a c-axis preferred orientation. A strong ultraviolet (UV) emission peak was observed for ZnO nanorods grown under optimized parameters with a low, deep-level emission peak, which indicated high optical property and crystallinity of the nanorods. The produced ZnO nanorods were also tested for their UV-sensing properties. All samples responded to UV light but with different sensing characteristics. Such different responses could be attributed to the high surface-to-volume ratio of the nanorods that correlated with the final ZnO nanorods morphology formed at different synthesis parameters. The sample grown using optimum synthesis parameters showed the highest responsivity of 0.024 A/W for UV light at 375 nm under a 3 V bias.
In this study, the authors report the production of nanocomposite-enhanced phase-change materials (NEPCMs) using the direct-synthesis method by mixing paraffin with alumina (Al2O3), titania (TiO2), silica (SiO2), and zinc oxide (ZnO) as the experimental samples. Al2O3, TiO2, SiO2, and ZnO were dispersed into three concentrations of 1.0, 2.0, and 3.0 wt.%. Through heat conduction and differential scanning calorimeter experiments to evaluate the effects of varying concentrations of the nano-additives on the heat conduction performance and thermal storage characteristics of NEPCMs, their feasibility for use in thermal storage was determined. The experimental results demonstrate that TiO2 is more effective than the other additives in enhancing both the heat conduction and thermal storage performance of paraffin for most of the experimental parameters. Furthermore, TiO2 reduces the melting onset temperature and increases the solidification onset temperature of paraffin. This allows the phase-change heat to be applicable to a wider temperature range, and the highest decreased ratio of phase-change heat is only 0.46%, compared to that of paraffin. Therefore, this study demonstrates that TiO2, added to paraffin to form NEPCMs, has significant potential for enhancing the thermal storage characteristics of paraffin.
To develop a novel plasmonic nanosensing technique to monitor the exposure levels of UV light for sunlight disease prevention.
UV light is an established carcinogen, yet evidence suggests that UV-seeking behavior has addictive features. Following UV exposure, epidermal keratinocytes synthesize proopiomelanocortin (POMC) that is processed to melanocyte-stimulating hormone, inducing tanning. We show that, in rodents, another POMC-derived peptide, β-endorphin, is coordinately synthesized in skin, elevating plasma levels after low-dose UV. Increases in pain-related thresholds are observed and reversed by pharmacologic opioid antagonism. Opioid blockade also elicits withdrawal signs after chronic UV exposure. This effect was sufficient to guide operant behavioral choices to avoidance of opioid withdrawal (conditioned place aversion). These UV-induced nociceptive and behavioral effects were absent in β-endorphin knockout mice and in mice lacking p53-mediated POMC induction in epidermal keratinocytes. Although primordial UV addiction, mediated by the hedonic action of β-endorphin and anhedonic effects of withdrawal, may theoretically have enhanced evolutionary vitamin D biosynthesis, it now may contribute to the relentless rise in skin cancer incidence in humans. PAPERCLIP:
Ultraviolet A (UV-A) light is associated with the risks of cataract and skin cancer.
UVB radiation generates sunburn pain and affects skin by activating epidermal TRPV4 ion channels and triggering endothelin-1 signaling
- Proceedings of the National Academy of Sciences of the United States of America
- Published about 4 years ago
At our body surface, the epidermis absorbs UV radiation. UV overexposure leads to sunburn with tissue injury and pain. To understand how, we focus on TRPV4, a nonselective cation channel highly expressed in epithelial skin cells and known to function in sensory transduction, a property shared with other transient receptor potential channels. We show that following UVB exposure mice with induced Trpv4 deletions, specifically in keratinocytes, are less sensitive to noxious thermal and mechanical stimuli than control animals. Exploring the mechanism, we find that epidermal TRPV4 orchestrates UVB-evoked skin tissue damage and increased expression of the proalgesic/algogenic mediator endothelin-1. In culture, UVB causes a direct, TRPV4-dependent Ca(2+) response in keratinocytes. In mice, topical treatment with a TRPV4-selective inhibitor decreases UVB-evoked pain behavior, epidermal tissue damage, and endothelin-1 expression. In humans, sunburn enhances epidermal expression of TRPV4 and endothelin-1, underscoring the potential of keratinocyte-derived TRPV4 as a therapeutic target for UVB-induced sunburn, in particular pain.
Introduction: Melanoma is considered a generally preventable cancer, with excessive ultraviolet radiation (UVR) exposure being a strong causal factor. UVR exposure following a melanoma diagnosis can be modified to reduce risk of second primary melanomas. The goal of this study was to compare measures of UVR exposure and protection behaviors between long-term melanoma survivors and controls.Methods: Participants from a previously conducted case-control study were recruited for a cross-sectional survey. Melanoma cases were 25 to 59 years old at diagnosis; controls were age and sex matched. Participants were asked about UVR exposure and protection measures used in the past year, and comparisons between melanoma survivors and controls were conducted using logistic regression models, adjusting for potential confounders.Results: A total of 724 (62.0%) long-term melanoma survivors and 660 (59.9%) controls completed the follow-up survey. Melanoma survivors were significantly less likely to report high sun exposure on a typical weekday [OR, 0.72 (0.55-0.94)], sunburns [OR, 0.40 (0.30-0.53)], or indoor tanning [OR, 0.20 (0.09-0.44)] than controls; however, high sun exposure on a typical weekend day was similar. Report of optimal sun protection behaviors was higher in melanoma survivors compared with controls. However, a few melanoma survivors reported indoor tanning, 10% reported intentionally seeking sun to tan, and 20% reported sunburns.Conclusions: Although long-term melanoma survivors reported healthier UVR exposure and protection behaviors compared with controls, a sizeable proportion still reported elevated sun exposure, sunburns, and suboptimal UVR protection behaviors.Impact: Opportunities remain for improving sun protection to reduce future melanoma risk among melanoma survivors. Cancer Epidemiol Biomarkers Prev; 1-7. ©2017 AACR.