Anthropogenic light at night (ALAN) can have serious impacts on marine environments. Several studies have demonstrated that ALAN disrupts melatonin production, a hormone critical for regulating circadian rhythm. In this study, the effects of ALAN on melatonin and two of its related indolamines were investigated in the annelid Hermodice carunculata. Specifically, melatonin, serotonin and tryptamine levels were measured every three hours over a 24 h period in the heads of the annelids maintained under constant light and a 12 h light/12 h dark photoperiod, representing control conditions. Melatonin concentration was quantified using an enzyme immunoassay, while serotonin and tryptamine were analyzed by liquid chromatography–tandem mass spectrometry. Melatonin levels in annelid heads remained relatively constant with a pronounced peak at 11:00. A similar pattern was observed under constant light, but the melatonin peak shifted to 14:00. However, serotonin and tryptamine did not exhibit any significant diurnal variations due to constant light exposure. These findings suggest that melatonin secretion in H. carunculata is sensitive to ALAN, whereas its related indolamines are potentially not. The disruption of H. carunculata's melatonin secretion pattern may affect its night-time behavior and reproduction, highlighting the need for further studies to assess the ecological effects of ALAN on various marine invertebrates.Graphical abstract

In Australia, skin cancer has the highest incidence of all cancer types, where Therapeutic Goods Association-approved, broad-spectrum sunscreens are recommended to prevent skin carcinogenesis. Commercial sunscreen ingredients, however, have been associated with negative impacts on human health, animal health and the environment. Together, the perceived harmful effects of commercial sunscreens have driven a trend towards home formulation of natural sunscreens, recipes for which are widely available online. Scientific evidence to support the efficacy of natural sunscreens, however, is lacking. We tested the efficacy of a natural homemade sunscreen (NHSS) published online by a wellness blogger with the aim to determine its photoprotective properties, beyond its ability to protect against erythema, compared to a commercially available SPF50 + sunscreen. The NHSS contained almond oil, coconut oil, shea butter, beeswax, red raspberry seed oil, carrot seed oil and zinc oxide. Skin explants were treated with either a commercial SPF50 + sunscreen, NHSS or base lotion prior to ultraviolet irradiation. Skin explants were assessed using immunohistochemistry for the levels of UVR-induced DNA damage in the form of cyclobutane pyrimidine dimers and 8-oxo-7, 8-dihydro-2’-deoxyguanosine, as well as for sunburn cells and epidermal thickness. We demonstrate herein that NHSSs can reduce UVR-induced DNA damage and epidermal thickness, but do not effectively protect against the generation of sunburn cells. In comparison, SPF50 + sunscreen provided effective protection against all investigated parameters. These factors, however, are markers of short-term UVR-induced damage and there is as yet no evidence for NHSSs in prevention of skin carcinogenesis. Therefore, we recommend the continued use of TGA-approved commercial sunscreens for sun protection. Further studies are required to test water resistance, variation in homemade formulation, shelf life, and protection against skin carcinogenesis in a chronic UVR model.Graphical

Carcinogenic effects of ultraviolet radiation (UVR) with reference to skin cancer are the basis of widely implemented recommendations to avoid sun exposure. Whether the benefits of “restrictive sun policies” outweigh their potential harms due to diminished beneficial effects of sunlight exposure remain a matter of controversy. A meeting of experts investigating the beneficial effects of UVR exposure, emphasizing those not mediated by vitamin D, took place in Washington, D.C. on May 27–28, 2024, an excerpt of which is presented here. The aim was to update an inventory of sound scientific data and research on a great variety of implicated health effects. Large cohort studies indicate that various measures of higher sunlight or UVR exposure are associated with improved overall life expectancy. Evidence is accumulating that UVR may prevent and improve various diseases, particularly those related to inflammatory pathologies, though where possible randomized controlled trials (RCTs) are still required to establish causality. Mechanistically, these beneficial effects of UVR extend far beyond vitamin D synthesis in the skin such as the lowering of blood pressure by nitric oxide released from the skin, and activation of neuro-immune–endocrine pathways by a plethora of other mediators at a local and systemic level. In conclusion, the compelling evidence on health benefits of UVR exposure requires serious consideration in public health policies to balance properly the harms and benefits of sunlight exposure and warrants further RCTs to explore the preventive and therapeutic potential of UVR irradiation.

Keratinocyte carcinoma is the most common cancer. Oral photoprotection offers an attractive addition to classical prevention measures. Popular candidates include nicotinamide and nicotinamide mononucleotide (NMN), which are NAD+ precursors thought to facilitate DNA repair. Extracts from the Polypodium leucotomos plant (PL) are also reported to convey broad protection against ultraviolet radiation (UVR) in both human and animal models. In this study, we evaluated the efficacy of NMN and PL treatment to prevent UVR-induced tumor development in hairless mice. Oral treatment with NMN or PL did not affect tumor development evaluated by tumor onset, number, size, or growth. Oral NMN increased NAD+ content in skin compared to the UVR control (p ≤ 0.00039) and liver tissue compared to the UVR control and non-exposed mice (p ≤ 0.0466) with no effect on tumor growth. We also demonstrated that UVR exposure induced urinary excretion of thymidine dimers in mice as measured by liquid chromatography–mass spectrometry, indicating that the induction of photodamage can be monitored non-invasively throughout the study period.

Multiple health problems are associated with either over- or under-exposure to ultraviolet (UV) radiation. Using an agent-based microsimulation model, we examined the joint health and economic effects of conditions arising from over-exposure to sunlight (i.e., melanoma, keratinocyte skin carcinoma (KC) and cataract) and under-exposure to sunlight via vitamin D deficiency (i.e., fragility fractures and multiple sclerosis). We developed an agent-based model to estimate and compare incident cases, disease-specific deaths, healthcare costs and losses in quality-adjusted life years (QALYs) attributable to over- or under-exposure to UV radiation. Simulations were performed over a 20-year period for populations in 14 locations across Australia and New Zealand. Conditions caused by over-exposure to UV radiation were predicted to result in 6.0 and 1.2 million new cases compared with 0.12 and 0.08 million cases from under-exposure in Australia and New Zealand, respectively. However, the number of deaths due to under-exposure (Australia: 58,503; New Zealand: 20,104) were higher than those arising from over-exposure (Australia: 49,320; New Zealand: 7136), but this was dependent on the definition of vitamin D deficiency used. The expected healthcare costs from over-exposure to UV radiation were AU$12.4 billion in Australia and NZ$5.2 billion in New Zealand, three-fold higher than costs for conditions attributable to under-exposure in both countries. Despite the enormous burden of skin cancers, highlighting the importance of sun protection, avoidable deaths and healthcare costs of fragility fractures due to a lack of UV radiation requires a reduction in vitamin D deficiency in Australians and New Zealanders.Graphical abstract

Ultraviolet (UV) radiation is a significant environmental stressor that affects the growth, physiology, and biochemical integrity of various organisms. This study investigates the potential protective effects of a zinc-cysteine (Zn–Cys) complex against UV-C radiation, with a focus on its impact on selected microalgae (Coccomyxa peltigerae and Parachlorella kessleri) and maize (Zea mays L.). We demonstrate that exposure of the Zn–Cys complex to UV-C (254 nm) results in the formation of fluorescent photoproducts, which exhibit UV-protective properties. The study reveals that Zn–Cys significantly mitigates UV-induced stress. In both microalgae species, the Zn–Cys complex enhanced growth even under UV exposure, with the 20% concentration showing the most robust protective effects. Further hyperspectral imaging confirmed the protective mechanism of Zn-Cys by monitoring changes in light reflectance in Parachlorella kessleri, indicating reduced photosynthetic efficiency and structural alterations induced by UV exposure, while Zn–Cys significantly mitigated these effects. In addition, in maize plants (Zea mays L.), Zn–Cys treatment preserved chlorophyll content and reduced polyphenol accumulation, indicating reduced oxidative stress. These findings highlight the potential of the Zn–Cys complex as a sustainable and cost-effective strategy for UV protection in both terrestrial and extraterrestrial agriculture, advancing our understanding of plant adaptation to extreme environments.

Hydrogen sulfide (H2S) holds a distinct role in cell biology. Its level is intricately linked to the homeostasis of the biological environment, underscoring the significance of developing techniques capable of detecting H2S in biological systems. A single probe that offers versatility across different detection techniques opens opportunities for advancements in sensing H2S in various fields. A nitronaphthalimide derivative, NMO prepared using a simple synthetic protocol, has been studied as an electrochemical, colorimetric, and turn-on fluorescence probe for H2S. NMO displayed a detection limit of 9.95 mM and 4.36 mM in the UV–visible and colorimetric studies, respectively, whereas the fluorometric and square wave techniques confirmed lower detection limits of 98.4 μM and 1.24 mM, correspondingly. Further, the real-time imaging of HEK293T cells using NMO during stress-induced autophagy is demonstrated.Graphical

Understanding the relationship between molecular structure and bioactivity is crucial for optimizing porphyrin-based therapeutics. By integrating cheminformatics techniques with machine learning models, our work enables the efficient classification of compounds based on their molecular structures and their growth inhibition capabilities (IC50). A dataset of 317 porphyrin derivatives was compiled, incorporating molecular descriptors and biological activity data. Descriptive statistical analysis was performed to examine compound distribution and key features. Clustering analysis was conducted using hierarchical clustering and fingerprint similarity matrices to classify compounds based on structural similarity. Lipinski’s Rule of Five was applied to assess drug-likeness, while Murcko scaffold analysis identified core structural patterns. Tumor response data were analyzed to evaluate therapeutic efficacy. Machine learning models were implemented to predict bioactivity. Descriptive statistics highlighted bioactive compounds, with TMPyP4 and Temaporfin being the most studied. Quantitative estimation of drug-likeness and the number of aliphatic carboxylic acids were identified as the most influential descriptors among others for bioactivity. Hierarchical clustering segmented porphyrins into nine structural groups. The analysis identified 168 pIC50 active compounds, with 31 meeting Lipinski’s criteria, and 11 overlapping as both effective and bioavailable. Tumor response analysis revealed three porphyrins achieving 100% response. Logistic Regression emerged as the best-performing model, achieving 83% accuracy, demonstrating robust predictive capabilities. This study successfully characterized porphyrin derivatives, reviewing key molecular features influencing bioactivity and evaluating their therapeutic potential. It highlights the potential of machine learning in predicting the biological activity status of porphyrin derivatives.Graphical abstract

Following the COVID-19 pandemic, portable UV-C radiation sources for disinfection have become increasingly available and integrated into daily life. UV-C devices emitting at 254 nm (mercury lamps) affect skin and eyes, usually causing erythema, burns or photokeratitis. Despite safety recommendations, misuse or accidental exposure remains a risk. Most data on UV-C effects come from cases of accidental overexposure in fixed installations, while portable devices involve different exposure geometry. Users hold the source close throughout the disinfection process, exposing themselves to both direct and reflected UV-C radiation. An in vivo study using male SKH-hr1 mice was conducted in two stages to assess the effects of skin exposure to UV-C radiation from a commercial disinfection device (Hg lamp, 253.7 nm, 5 Wm−2) under realistic conditions of use. In the first stage, single irradiation doses of 5 Jm−2, 15 Jm−2, 30 Jm−2, 45 Jm−2 and 60 Jm−2 were used to determine the minimum erythemal dose. Doses of 45 Jm−2 and 60 Jm−2 caused irritation and signs of skin aging including reduced elasticity, wrinkling and dry skin. Based on these findings, the second stage assessed long-term effects with repeated exposures of 45 Jm−2, 60 Jm−2, and 100 Jm−2, irradiating mice 5 times per week for 25 days. Progressive skin damage escalated from mild irritation to significant thickening and premature aging, culminating in erythematous papules indicative of actinic hyperkeratosis. These findings demonstrate that both acute and long-term exposure to UV-C radiation can cause significant skin damage, emphasizing the need for strict adherence to safety guidelines.Graphical abstract

Optical trapping at interfaces has emerged as a valuable research topic in the study of colloidal particles and soft matter. Objects are drawn from the irradiated cone-like region toward the laser focus, generating flow patterns beyond the focal area. Localized heating at the focus induces coupled effects on surface tension, capillary forces, and Marangoni convection. Furthermore, optical propagation and scattering of the trapping laser beyond the focus can lead to the formation of large assemblies along the interface, extending well beyond the laser beam itself. For gold nanoparticles, a single large swarming assembly forms, with individual nanoparticles exhibiting vivid fluctuations. In this study, we investigate the swarming assembly as a non-linearly evolving optical matter using a plastic microchannel. The original structure undergoes transformations into pressed, square, unidirectional, triangular, elongated rectangular, or even twisted assemblies. In addition, the photothermal effects of the optical matter are analyzed in the context of a local anisotropic heater. This phenomenon not only suggests potential applications but also offers valuable insights for advancing new technologies.Graphical