Ultraviolet Radiation Exposure Research Articles

Updates in the care and management of children and adolescents with systemic lupus erythematosus.

This narrative review offers an update of the most important recent articles published in the previous year of childhood-onset systemic lupus erythematosus (cSLE), focusing on care and management. Age-related disparities may play a significant role in the clinical and laboratory characteristics of cSLE, as well as its performance in distinct classification criteria. Monogenic lupus is associated with higher disease damage scores and mortality rate compared to sporadic cSLE. Adolescent face unique challenges, with comorbid psychiatric diagnosis, low resilience and nonadherence posing relevant challenges. A recent international task force has outlined pivotal principles and points-to-consider for treat-to-target (T2T) in cSLE patients. While the past year did yield new randomized controlled trial for cSLE treatment, publications focused on broader management strategies, including the impact of ultraviolet radiation exposure, immunization, and strict blood pressure control. Additionally, case reports and series have evaluated the efficacy/safety profiles of both available and emerging treatments. Current studies highlighted the various facets of cSLE, epidemiology, clinical, laboratory, classification criteria, adolescent issues, prognosis, surveillance, T2T approach and drug management. Despite notable progress, the scarcity of randomized trials emphasizes the need to delineate safer and more efficacious treatment modalities in cSLE.

Understanding Mechanisms and Key Factors Influencing Melanogenesis for the Management of Melasma: An Updated Review.

Melanocytes are highly specialized dendritic cells that deliver melanin to keratinocytes in melanosomes, which are subcellular organelles where melanin is produced and stored. Mammal's skin, hair, and eyes all contain the complex pigment melanin, which gives them color and ultraviolet protection. Melanins have the potential to be free radical sinks and are strong cation chelators. Amino acid tyrosine and its metabolite, dopa, are the precursors to complex metabolic processes that end with melanin production. Melanocytes generate different types and amounts of melanin, which is defined genetically and is impacted by several extrinsic and intrinsic factors such as hormone fluctuations, inflammation, age, and ultraviolet radiation exposure, leading to the stimulation of numerous melanogenesis pathways. Melasma, a common skin pigmentation condition, is associated with the overproduction of melanin and is characterized by brown to gray-brown and black spots that mostly affect the face. The present review addresses the regulatory mechanisms and signaling pathways involved in skin pigmentation with an emphasis on the altered melanogenesis that causes melasma and hyperpigmentation. The current study also illustrates the available treatment options with cellular and molecular mechanisms for the management of melasma. Understanding the mechanism of the pigmentation process may help researchers develop new therapeutic strategies and novel drugs for the management of melasma.

Effects of temperature up-shift and UV-A radiation on fatty acids content and expression of desaturase genes in cyanobacteria Microcystis aeruginosa: stress tolerance and acclimation responses.

Temperature up-shift and UV-A radiation effects on growth, lipid damage, fatty acid (FA) composition and expression of desaturase genes desA and desB were investigated in the cyanobacteria Microcystis aeruginosa. Although UV-A damaging effect has been well documented, reports on the interactive effects of UV radiation exposure and warming on cyanobacteria are scarce. Temperature and UV-A doses were selected based on the physiological responses previously obtained by studies with the same M. aeruginosa strain used in this study. Cells pre-grown at 26°C were incubated at the same temperature or 29°C and exposed to UV-A + PAR and only PAR for 9days. Growth rate was significantly affected by UV-A radiation independently of the temperature throughout the experiment. High temperature produced lipid damage significantly higher throughout the experiment, decreasing at day 9 as compared to 26°C. In addition, the cells grown at 29°C under UV-A displayed a decrease in polyunsaturated FA (PUFA) levels, with ω3 PUFA being mostly affected at the end of exposure. Previously, we reported that UV-A-induced lipid damage affects differentially ω3 and ω6 PUFAs. We report that UV-A radiation leads to an upregulation of desA, possibly due to lipid damage. In addition, the temperature up-shift upregulates desA and desB regardless of the radiation. The lack of lipid damage for UV-A on ω3 could explain the lack of transcription induction of desB. The significant ω6 decrease at 26°C in cells exposed to UV-A could be due to the lack of upregulation of desA.

Blocking the ATR-SerRS-VEGFA pathway targets angiogenesis for UV-induced cutaneous squamous cell carcinoma.

Cutaneous squamous cell carcinoma (cSCC) is the second most prevalent form of skin cancer, with an escalating incidence rate and a notable potential (up to 5%) for metastasis. Ultraviolet radiation (UVA and UVB) exposure is the primary risk factor for cSCC carcinogenesis, with literature suggesting ultraviolet radiation (UVR) promotes vascular endothelial growth factor A (VEGFA)expression. This study aims to investigate UVR-induced upregulation of VEGFA and explore combination therapeutic strategies. The skin squamous cell carcinoma cell line A431 was exposed to specific durations of ultraviolet radiation. The effect of emodin on ATR/SerRS/VEGFA pathway was observed. The cell masses were also transplanted subcutaneously into mice (n = 8). ATR inhibitor combined with emodin was used to observe the growth and angiogenesis of the xenografts. The results showed that UV treatment significantly enhanced the phosphorylation of SerRS and the expression level of VEGFA in A431 cells (p < 0.05). Treatment with emodin significantly inhibited this expression (p < 0.05), and the combination of emodin and ATR inhibitor further enhanced the inhibitory effect (p < 0.05). This phenomenon was further confirmed in the xenograft model, which showed that the combination of ATR inhibitor and emodin significantly inhibited the expression of VEGFA to inhibit angiogenesis (p < 0.05), thus showing an inhibitory effect on cSCC. This study innovatively reveals the molecular mechanism of UV-induced angiogenesis in cSCC and confirms SerRS as a novel target to inhibit cSCC angiogenesis and progression in vitro and in vivo studies.

Impact of artificial accelerated ageing of PVC surfaces and surface degradation on disinfectant efficacy

Standardised efficacy surface tests for disinfectants are performed on pristine surfaces. There is a growing interest in understanding the impact of surface ageing on disinfectant activity, owing for example to the increased usage of UV radiation and oxidative chemistries for surface decontamination. This acknowledges that general surface "wear and tear" following UV radiation and oxidative biocide exposure may impact biocidal product efficacy. PVC surfaces were aged through thermal and UV-A radiation (340nm wavelength) following the use of standard ageing surface protocols to simulate natural surface degradation. Surface roughness, contact angle and scanning electron microscopy were performed to evaluate physical changes in PVC surfaces before and after artificial ageing. The efficacy of five pre-impregnated disinfectant wipes were evaluated using the ASTM E2967-15 on stainless steel (control) and PVC surfaces (aged and non-aged). The type of formulation and the organism tested remained the most significant factors impacting disinfectant efficacy, compared to surface type. Both thermal ageing and UV-A exposure of PVC surfaces, clearly showed signs of surface degradation, notably an increase in surface roughness. Physical changes were observed in the roughness of PVC after artificial ageing. A difference in disinfectant efficacy dependent on aged PVC surfaces was observed for some, but not all formulations. We showed that surface type and surface ageing can affect biocidal product efficacy, although in a non-predictable manner. More research is needed in this field to ascertain whether surface types and aged surfaces should be used in standardized efficacy testing.

Myopia prevalence and ocular biometry in children and adolescents at different altitudes: a cross-sectional study in Chongqing and Tibet, China

ObjectiveTo investigate the differences in myopia prevalence and ocular biometry in children and adolescents in Chongqing and Tibet, China.DesignCross-sectional study.SettingThe study included children and adolescents aged 6–18 years in Chongqing,...

Comparative Study of Healthy Older and Younger Adults Shows They Have the Same Skin Concentration of Vitamin D3 Precursor, 7-Dehydrocholesterol, and Similar Response to UVR.

Vitamin D3 synthesis in human skin is initiated by solar ultraviolet radiation (UVR) exposure of precursor 7-dehydrocholesterol (7DHC), but influence of age on the early stage of vitamin D3 metabolism is uncertain. We performed a prospective standardised study in healthy ambulant adults aged ≥65 and ≤40 years examining (1) if baseline skin 7DHC concentration differs between younger and older adults and (2) the impact of older age on serum vitamin D3 response to solar simulated UVR. Eleven younger (18-40 years) and 10 older (65-89 years) adults, phototype I-III, received low-dose UVR (95% UVA, 5% UVB, 1.3 SED) to ~35% of the body surface area. Biopsies were taken for 7DHC assay from unexposed skin, skin immediately and 24 h post-UVR, and blood sampled at baseline, 24 h and 7 d post-UVR for vitamin D3 assay. Samples were analysed by HPLC-MS/MS. Baseline skin 7DHC (mean ± SD) was 0.22 ± 0.07 and 0.25 ± 0.08 µg/mg in younger versus older adults (no significant difference). Baseline serum vitamin D3 concentration was 1.5 ± 1.5 and 1.5 ± 1.7 nmol/L in younger versus older adults, respectively, and showed a significant increase in both groups post-UVR (no significant differences between age groups). Thus, skin 7DHC concentration was not a limiting factor for vitamin D3 production in older relative to younger adults. This information assists public health guidance on sun exposure/vitamin D nutrition, with particular relevance to the growing populations of healthy ambulant adults ≥65 years.

Improving the stability and transdermal permeability of phycocyanin loaded cubosomes

Instability and low transdermal permeability of protein antioxidants are major obstacles to resist oxidative stress in transdermal drug delivery system. To overcome these shortcomings, cubosomes were developed as an advanced transdermal delivery system to improve stability and transdermal absorption of the model antioxidant phycocyanin in this study. Glyceryl monooleate and poloxamer 407 (P407) were used to prepare cubosomes as carrier matrix and stabilizer, respectively. Phycocyanin loaded cubosomes (PC-cubosomes) were prepared by the emulsification and homogenization method. A 33 full factorial design was used to optimize the cubosome formulations. The final optimal PC-cubosomes possessed an average particle size of 183.2 ± 0.5 nm and a negative surface charge as well as achieved a high encapsulation efficiency of 87.2% ± 2.7%. PC-cubosomes appeared as nano-sized and well-shaped spheres with highly ordered cubical structures. The residual amount of phycocyanin in PC-cubosomes was 3-fold higher than that in the free drug solution after 10 days ultraviolet radiation exposure. In vitro release kinetics of phycocyanin from PC-cubosomes fitted to the Higuchi kinetic model, indicating that phycocyanin released from cubosomes mainly attributed to drug diffusion and dissolution. PC-cubosomes also exhibited higher permeability (39.79 μg⋅cm−2⋅hour−1) across the rat skin than phycocyanin solution (16.33 μg⋅cm−2⋅hour−1). Furthermore, PC-cubosomes were easily taken up by keratinocytes, thereby achieving a prolonged anti-oxidative stress effect. These results therefore suggested that cubosomes could be a promising transdermal delivery system to improve the stability and transdermal permeability of phycocyanin.

Urinary thymidine dimer excretion reflects personal ultraviolet radiation exposure levels.

Exposure to ultraviolet radiation (UVR) leads to skin DNA damage, specifically in the form of cyclobutane pyrimidine dimers, with thymidine dimers being the most common. Quantifying these dimers can indicate the extent of DNA damage resulting from UVR exposure. Here, a new liquid chromatography-mass spectrometry (LC-MS) method was used to quantify thymidine dimers in the urine after a temporary increase in real-life UVR exposure. Healthy Danish volunteers (n = 27) experienced increased UVR exposure during a winter vacation. Individual exposure, assessed via personally worn electronic UVR dosimeters, revealed a mean exposure level of 32.9 standard erythema doses (SEDs) during the last week of vacation. Morning urine thymidine dimer concentrations were markedly elevated both 1 and 2days post-vacation, and individual thymidine dimer levels correlated with UVR exposure during the last week of the vacation. The strongest correlation with erythema-weighted personal UVR exposure (Power model, r2 = 0.64, p < 0.001) was observed when both morning urine samples were combined to measure 48-h thymidine dimer excretion, whereas 24-h excretion based on a single sample provided a weaker correlation (Power model, r2 = 0.55, p < 0.001). Sex, age, and skin phototype had no significant effect on these correlations. For the first time, urinary thymidine dimer excretion was quantified by LC-MS to evaluate the effect of a temporary increase in personal UVR exposure in a real-life setting. The high sensitivity to elevated UVR exposure and correlation between urinary excretion and measured SED suggest that this approach may be used to quantify DNA damage and repair and to evaluate photoprevention strategies.

Is beauty worth the risk? Self-confidence is the key motivating factor driving tanning bed use among undergraduate students at South Dakota universities.

Exposure to ultraviolet radiation is a leading risk factor for developing all types of skin cancer. In the United States, an estimated 7.8 million young adults engage in indoor tanning. Here, it is hypothesized that certain populations of students at undergraduate universities, namely sorority members, have a greater frequency of tanning bed usage than other groups of students and that regardless of sorority status, the most important motivating factor will be the intent to enhance one's appearance. Undergraduate students at 2 state-funded universities were recruited for participation in this institutional review board-exempt survey via distribution to e-mail addresses and social media accounts affiliated with student organizations/clubs. Among all respondents, the most common motivating factors for tanning bed use were the perception of improved self-appearance and boosted self-confidence. Female sorority members were more likely to use tanning beds and also more likely to report being motivated by enhanced appearance and self-confidence, than their female counterparts who were not sorority members. The sample size (n = 321) and population of this study allows data to only be generalizable to surrounding states with similar demographics. The findings of this study are subject to recall bias as the data is self-reported. Tanning bed use remains a popular practice among young people. Understanding motivations for tanning bed use among populations at increased risk of partaking in this behavior allows for educating these groups on the risks associated with ultraviolet radiation exposure. It is crucial that providers continue to promote skin health and take steps to dissuade detrimental practices and possible habit-forming behaviors at the individual and state levels.

Cutaneous Malignancies: A Prospective Study of Demographic Patterns, Risk Factors, and Clinical Spectrum at a Tertiary Care Center in South India

Background and Objectives: The incidence of skin cancer is increasing worldwide and is causing a massive burden to the health-care system. It arises as a result of interplay between various predisposing factors. We intend to study the various clinical presentations of cutaneous malignancies and the demographic pattern and risk factors associated with them. Methodology: The study was done over a period of 7 years, 181 patients were diagnosed with cutaneous malignancy in the department of dermatology of our tertiary care hospital. A diagnosis was done based on history, clinical and histopathological examination. Results: Of 181 patients, majority of the patients belonged to 7th decade (n = 56, 31%) with the mean age being 55 years. The study group had 105 males (58%) and 76 (42%) females. The most common site was the head-and-neck region (n = 105, 58%). The most important associated condition/predisposing factor was ultraviolet (UV) radiation exposure (n = 79, 44%). Keratinocytic tumors formed the largest group (n = 131, 72%) in which basal cell carcinoma (BCC) was the most common (n = 75, 41%). Surgical excision was the main modality of treatment and was done in 111 (61%) patients. Conclusion: BCC was the most common skin cancer with head-and-neck region being the most common location in our study. Important risk factors were increasing age, male sex, and prolonged exposure to UV radiation. Early diagnosis helps in planning effective management strategies.

Abstract 867: Molecular and functional characterization of melanocyte subpopulations in human epidermis based on single-cell RNA sequencing

Abstract The biological and molecular mechanisms that underpin the malignant transformation of normal melanocytes to melanomas are largely unknown. In part, this is due to the limited understanding of normal human melanocyte homeostasis and how melanocytes respond to oncogenic insults such as ultraviolet radiation (UVR). This is particularly true for interfollicular epidermal melanocytes, which have the highest levels of UVR exposure and from whence most melanomas are thought to arise. These knowledge gaps impede the development of strategies for active, targeted prevention of melanoma formation. We thus evaluated epidermal melanocytes transcriptionally, phenotypically and functionally after isolating them from human skin. Using single-cell RNA sequencing (scRNA-seq), we identified multiple transcriptionally distinct subpopulations within human epidermal melanocytes. RNA velocity analysis revealed subpopulations in different states of melanocytic differentiation, and immunohistochemistry staining demonstrated their distinct anatomical distribution throughout follicular and interfollicular epidermal compartments. Notably, one melanocyte subgroup, marked by increased expression of neurotrophic receptor tyrosine kinase 2 (NTRK2) and genes associated with ribosome biogenesis, exhibited molecular characteristics of progenitor cells. This subpopulation displayed human embryonic stem cell (hESC)-derived melanoblast markers, and their anatomical localization corresponded to that of intermediate melanocyte progenitors. NTRK2+ melanocytes demonstrated enhanced clonogenicity after UVR exposure in primary cell cultures and in ex vivo whole skin explants. In contrast, NTRK2- melanocytes were suppressed by UVR. Furthermore, scRNA-seq data of ex vivo melanocytes after UVR exposure revealed the upregulation of genes associated with cell proliferation within NTRK2-expressing melanocytes. In mouse back skin, the ratio of Ntrk2+ melanocytes increased within 24 hours of UVB irradiation, suggesting a proliferative response in these cells in vivo following UVR. We thus report the discovery in human epidermis of a putative melanocytic cell hierarchy, and of a candidate melanocyte progenitor subpopulation that responds proliferatively to UVR and is thus a candidate cell of origin of melanoma. Citation Format: Peinan Zhao, Fumihito Noguchi, Christopher Chew, Gamze Kuser Abali, Pacman Szeto, Youfang Zhang, Malaka Ameratunga, Isobel Leece, Jen G. Cheung, Miles Andrews, Nicholas C. Wong, Anthony T. Papenfuss, Mark Shackleton. Molecular and functional characterization of melanocyte subpopulations in human epidermis based on single-cell RNA sequencing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 867.

Abstract 843: The burden of Merkel cell carcinoma attributable to immunosuppression, ultraviolet radiation, and Merkel cell polyomavirus in the United States

Abstract Background: Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer. No published study has estimated the contribution of the major potentially modifiable risk factors, such as immunosuppression, ultraviolet radiation (UVR) and infection with Merkel cell polyomavirus (MCPyV), to the burden of MCC in the US. We estimated the population attributable fractions (PAFs) for MCC associated with immunosuppression (HIV and organ transplantation), MCPyV, and UVR in the US during 2001-2020. Methods: We calculated PAFs for immunosuppression and UVR using the formula: prevalence in cases (Pc)*[(Relative risk, RR-1)/RR]. The proportion of MCC cases among organ recipients and people with HIV (Pc) were derived from US cancer registries in the HIV/AIDS Cancer Match Study, Transplant Cancer Match Study, and the Surveillance Epidemiology and End Results (SEER) Program data. To approximate the RRs, we calculated standardized incidence ratios (SIRs) comparing MCC incidence in people with HIV and organ recipients to the general population. We merged SEER data on MCC cases by county with data on ambient UVR levels in order to create population quintiles of UVR exposure. Since only non-Hispanic White individuals showed elevated IRRs for increased ambient UVR exposure, we estimated the PAF of UVR by calculating incidence rate ratios (IRR ≈ RR) comparing MCC incidence in non-Hispanic White individuals to all other races/ethnicities (at any UVR level) as the reference; here, Pc was the proportion of non-Hispanic White patients in each quintile. To estimate the PAF of MCPyV, we meta-analyzed US studies reporting on MCPyV prevalence in MCC tissues (here PAF ≈ Pc). Results: Over the study period (2001-2020), 40,571 MCCs were diagnosed in the US. Compared to the general population, organ recipients had 13 times higher (SIR=12.7, CI: 11.3-14.2) and people with HIV had three times higher (SIR=2.78, CI: 2.01-3.75) risk of MCC. Due to the rarity of these exposures (HIV Pc = 0.4%; Transplant Pc = 1.9%), only 0.2% of MCC cases were attributable to HIV and 1.7% were attributable to organ transplantation. Compared with people in other racial/ethnic groups, the IRRs of non-Hispanic White individuals at the various levels of ambient UVR for MCC arising on the head and neck ranged from 4.24 to 5.03 and for other primary sites ranged from 2.81 to 3.36. After combining the PAFs for these sites, the overall PAF for UVR was 65.8%. Meta-analyzing 20 studies with 984 MCC cases combined, we found that 66.1% (CI: 58.0-72.2%) of MCCs were attributable to MCPyV. Conclusions: While a small proportion of MCCs were due to immunosuppression from HIV infection and organ transplantation, UVR and MCPyV played a major role in MCC burden. Future research is required to assess the combined impact of these risk factors on MCC incidence. Citation Format: Jacob T. Tribble, Karena Volesky-Avellaneda, Qianlai Luo, Michael R. Sargen, Isaac Brownell, Elizabeth K. Cahoon, Meredith Shiels, Ruth Pfeiffer, Adrianne Moreno, Brenda Y. Hernandez, Eric Engels. The burden of Merkel cell carcinoma attributable to immunosuppression, ultraviolet radiation, and Merkel cell polyomavirus in the United States [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 843.

Abstract 273: Extrinsic photoaging vs intrinsic aging in dermal fibroblasts: Its impact on the microenvironment and melanoma progression

Abstract Melanoma is the deadliest form of skin cancer, with chronological aging as a major negative prognostic factor due to the influence of intrinsic aging on the tumor microenvironment (TME) to promote tumor initiation and progression. Ultraviolet radiation (UVR) exposure, which is a major risk factor for melanoma, also can cause a physical premature aging phenotype, known as extrinsic photoaging, from chronic UVA irradiation of the underlying dermis. Photoaging of the skin often occurs in tandem with chronological aging, and contributes to similar physical alterations in normal skin structure. However, the molecular mechanisms of how photoaging compares to chronological aging in changing the TME and on tumor progression is still lacking. Here we found that extrinsically photoaged fibroblasts have a higher level of secretion of lysosomal proteases, Cathepsins, which have been shown to be secreted via lysosomal exocytosis and play a functional role in extracellular matrix (ECM) remodeling at neutral PH levels. We found that Cathepsins B and D are secreted at higher levels in both extrinsically photoaged young fibroblasts and in intrinsically aged fibroblasts and upregulated at the endogenous protein level. Cathepsin B has been shown to be highly expressed in metastatic but not primary melanoma patient samples, and cleaves ECM proteins such as fibronectin and tenascin. Immunofluorescent staining of in-vitro fibroblast derived matrices (CDMs) confirmed that photoaging disrupts subsequent deposited extracellular matrix proteins similarly to that of intrinsically aged healthy fibroblasts and these matrix changes influences the growth pattern of melanoma lines plated on these CDMs. Mass spectrometry analysis of secreted proteomics confirmed that aged fibroblasts secrete more cathepsins than intrinsically young fibroblasts, and Cathepsins B and D were also detected in extracellular vesicle (EV) cargo proteomics. Single-Particle Interferometric Reflectance Imaging (SP-IRIS) of EVs showed that UVA irradiation induced a significant increase in the total number of secreted of exosomes and in expression of tetraspanin protein CD63, which plays a role in cargo sorting and has been detected in high levels in the plasma of melanoma patients. We hypothesize that extrinsic photoaging of fibroblasts induces the secretion of exosomes packaged with Cathepsins that play an integral role in ECM remodeling and matrix degradation in a beneficial manner for melanoma invasion. Further studies will assess the influence on secreted cathepsins on melanomagenesis and melanoma invasion through both mechanical and biochemical changes in the TME with in-vitro and in-vivo studies. Citation Format: Vania Wang, Yash Chhabra, Laura Hueser, Ashani Weeraratna. Extrinsic photoaging vs intrinsic aging in dermal fibroblasts: Its impact on the microenvironment and melanoma progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 273.

Comparing the Aging Processes of PLA and PE: The Impact of UV Irradiation and Water

The aging processes of microplastics (MPs) are prevalent in natural environments. Understanding the aging mechanisms of MPs is crucial for assessing their environmental behavior and potential risks. In this study, we selected polylactic acid (PLA) and polyethylene (PE) as representatives of biodegradable and conventional plastics, respectively, to examine changes in their physicochemical properties induced by water and UV light exposure. Laboratory aging resulted in significant fragmentation, characterized by cracks and pores on the surfaces, for both types of MPs, with PLA MPs exhibiting more severe changes, particularly under combined UV and water exposure. Notably, PLA MPs tended to become progressively smaller after aging, whereas PE MPs did not show significant size changes. Chemical analyses of aged MPs using micro-Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) revealed a substantial increase in the carbonyl index (CI) and oxygen content for PE, suggesting surface oxidation during photo-oxidation. Conversely, PLA MPs displayed a CI decrease, along with an oxygen content increase, indicating the breakdown of ester linkages in PLA and the formation of other oxidation products. Furthermore, we developed and optimized pyrolysis–gas chromatography–mass spectrometry (Py–GC–MS) methods to identify potential chemical degradation products of PE and PLA, considering their differing thermal stabilities. We observed a distinct trend regarding the peaks in the chromatogram of aged MPs and identified the typical oxidation and crosslinking products for PLA. Additionally, after the aging process, both PE and PLA exhibited a significant increase in organic carbon content, with the eluate containing submicron/nano-sized particles. This study provides a scientific foundation for a deeper understanding of the environmental aging mechanisms of various MPs, particularly in regards to the effects of UV irradiation and water exposure.

Advancements in elucidating the pathogenesis of actinic keratosis: present state and future prospects.

Solar keratosis, also known as actinic keratosis (AK), is becoming increasingly prevalent. It is a benign tumor that develops in the epidermis. Individuals with AK typically exhibit irregular, red, scaly bumps or patches as a result of prolonged exposure to UV rays. These growths primarily appear on sun-exposed areas of the skin such as the face, scalp, and hands. Presently, dermatologists are actively studying AK due to its rising incidence rate in the United States. However, the underlying causes of AK remain poorly understood. Previous research has indicated that the onset of AK involves various mechanisms including UV ray-induced inflammation, oxidative stress, complex mutagenesis, resulting immunosuppression, inhibited apoptosis, dysregulated cell cycle, altered cell proliferation, tissue remodeling, and human papillomavirus (HPV) infection. AK can develop in three ways: spontaneous regression, persistence, or progression into invasive cutaneous squamous cell carcinoma (cSCC). Multiple risk factors and diverse signaling pathways collectively contribute to its complex pathogenesis. To mitigate the risk of cancerous changes associated with long-term UV radiation exposure, prompt identification, management, and prevention of AK are crucial. The objective of this review is to elucidate the primary mechanisms underlying AK malignancy and identify potential treatment targets for dermatologists in clinical settings.

A Social Media-Delivered Melanoma Prevention Program for Young Women Engaged in Frequent UV Tanning: Protocol for a Randomized Controlled Trial.

Rates of melanoma have increased dramatically in the United States over the past 25 years, and it has become among the most prevalent cancers for young adult women. Intentional skin tanning leads to a pattern of intense and intermittent UV radiation exposure that is associated with increased risk of melanoma. Frequent tanning is most common among young women and is linked to a variety of sociocultural pressures that negatively impact body image and drive appearance control behaviors. Unfortunately, there are no established interventions designed for frequent tanners. This intervention addresses this gap with unique content informed by body image and acceptance-based interventions. The intervention is delivered using Facebook secret groups, an approach designed to support behavior change and ensure scalability. This study aims to describe the rationale and methodology of a randomized controlled trial of a melanoma prevention program targeting young women engaged in frequent indoor or outdoor UV tanning. Participants are women aged 18-25 years who report high-risk tanning (ie, at least 10 indoor tanning sessions in the past 12 months or 10 outdoor sessions in the previous summer). After recruitment and screening, participants completed a baseline survey and were randomly assigned to receive the intervention or an attention-matched control condition. Both conditions were 8-week-long Facebook groups (approximately 25 members each) with daily posting of content. Follow-up surveys are administered at 3, 8, and 18 months after baseline. The primary trial outcome is the combined number of indoor and outdoor tanning sessions reported at the 8-month follow-up. Hypothesized intervention mediators are assessed at the 3-month follow-up. This project was funded by a National Cancer Institute award (R01 CA218068), and the trial procedures were approved by the University of Kentucky Institutional Review Board in February 2020. Trial recruitment and enrollment occurred in 6 waves of data collection, which started in February 2022 and closed in May 2023. The study is closed to enrollment but remains open for follow-ups, and this protocol report was prepared before data analyses. As of February 2024, all participants have completed the 8-month follow-up assessment, and data collection is scheduled to close by the end of 2024 after the collection of the 18-month follow-up. This trial will contribute unique knowledge to the field of skin cancer prevention, as no fully powered trials have examined the efficacy of an intervention designed for frequent indoor or outdoor tanning. The trial may also contribute evidence of the value in translating principles of body image and acceptance-based interventions into the field of skin cancer prevention and beyond. If successful, the use of the Facebook platform is intended to aid in dissemination as it provides a way to embed the intervention into individuals' everyday routines. ClinicalTrials.gov NCT03441321; https://clinicaltrials.gov/study/NCT03441321. DERR1-10.2196/56562.

Acute exposure to ultraviolet radiation targets proteins involved in collagen fibrillogenesis.

Introduction: Exposure to chronic, low-dose UV irradiation (UVR) can lead to premature ageing of the skin. Understanding which proteins are affected by acute UVR and photo-dynamically produced reactive oxygen species (ROS) could help to inform strategies to delay photoageing. Conventional biochemical analyses can be used to characterize UVR/ROS-induced damage on a protein-by-protein basis and we have previously shown using SDS-PAGE that collagen I and plasma fibronectin are respectively resistant and susceptible to physiological doses of UVR. The aim of this study was to screen a complex proteome for UVR-affected proteins. Methods: This study employed a sensitive mass spectrometry technique (peptide location fingerprinting: PLF) which can identify structure associated differences following trypsin digestion to characterize the impact of UVR exposure on purified collagen I and tissue fibronectin and to identify UVR-susceptible proteins in an ECM-enriched proteome. Results: Using LC/MS-MS and PLF we show that purified mature type-I collagen is resistant to UVR, whereas purified tissue fibronectin is susceptible. UV irradiation of a human dermal fibroblast-deposited ECM-enriched proteome in vitro, followed by LC/MS-MS and PLF analysis revealed two protein cluster groups of UV susceptible proteins involved in i) matrix collagen fibril assembly and ii) protein translation and motor activity. Furthermore, PLF highlighted UV susceptible domains within targeted matrix proteins, suggesting that UV damage of matrix proteins is localized. Discussion: Here we show that PLF can be used to identify protein targets of UVR and that collagen accessory proteins may be key targets in UVR exposed tissues.

Tuning of ultraviolet‐curable ink printability via in situ ultraviolet irradiation during direct ink write applications

AbstractDirect ink write deposition facilitates line‐by‐line extrusion of inks spanning wide viscoelastic ranges. Following deposition, post processing technologies permit tuning of the extrudate's material property characteristics—ultraviolet (UV) irradiation, facilitating the photopolymerization of UV‐reactive catalyst solutions, permits targeted modification of the extrudate's microstructure and in situ tuning of extrudate macrostructure. This report analyzes the morphological, rheological, and microstructural property relationships governing the printability, and processivity, of extruded UV‐curable resin inks for delineation of sufficiency and optimization of ink printability utilizing direct ink write technologies. A design‐of‐experiments approach is implemented to quantify significance regarding an extrudate's dimensional response to extrusion parameter variation and in situ processing parameters, identifying proportionally of nozzle velocity, nozzle height, and UV irradiation exposure with extrudate aspect ratio, reflected by respective maximum extrudate aspect ratio increases of 158% and 109%, regarding 121 and 123K resin inks. Finally, the relationship between extrudate morphology and microstructure variation was assessed via dielectric cure monitoring, whereby an extrudate's ion viscosity was calculated in relation to its rheological modulus, reflecting the relationship between an extrudate's morphology, rheological response, and printability, regarding its microstructural variation.

Occupational Health Challenges for Aviation Workers Amid the Changing Climate: A Narrative Review.

Although there are many forecasts regarding the impact of climate change on the aviation sector, a critical but frequently neglected dimension is the occupational safety risks faced by aviation professionals. This narrative review explores the potential impacts of the changing climate on the health and safety of aviation personnel. Furthermore, we examine the significance of resilience in helping these workers adapt and effectively manage climate-related challenges in their professional lives. Climate change poses increasing threats to the well-being of flight personnel through elevated temperatures, heightened ultraviolet radiation exposure, increased mental workload from extreme weather events, and other psychological stressors. Building resilience through workforce training, planning, and adaptation can reduce vulnerability. In future research, the iterative process of selecting measurement components to gauge the impact of climate change should balance feasibility, relevance for stakeholders, and accurately capturing exposure effects. For instance, while salivary cortisol measures stress biologically, assessments of depression or burnout may provide more nuanced insights on pilot health for industry decision-makers managing climate impacts. In conclusion, a strategic emphasis on enhancing the physical and psychological well-being of the aviation workforce is imperative for facilitating a more efficient adaptation within the sector. This is of paramount importance, considering the critical function that aviation serves in fostering human connectivity. Consequently, it is essential for regulatory bodies and policymakers to prioritize the safeguarding of employee health in the face of climate change challenges.