Search Results (220)

Melanin is the dark polymer pigment found in all kingdoms of life. Plant allomelanin, formed through the oxidation and polymerization of phenolic compounds, does not contain nitrogen; however, it possesses similar properties to melanin of animal, fungal, or bacterial origin. The black coloration of awns, spike husk edges, and even complete spikes is well-known in wheat and occurs frequently in wild, but rarely in cultivated, wheat species. Previously, anthocyanins were considered the only pigments responsible for the black coloration of wheat ears. Recently, it has been shown that the black coloration of the husks in other cereals can be attributed to melanin or anthocyanins, or both of these pigments. In this study, using standard procedures for chemical extraction of anthocyanins and melanin, ultraviolet–visible–near-infrared spectroscopy, and hyperspectral imaging, we examined the pigment in Persian wheat (Triticum carthlicum Line 5999) black-colored spikes and found that it exhibits properties characteristic of melanin rather than anthocyanins. Also, using microscopy, we show that the dark pigment in the husks and awns of mature spikes is located mainly in the dead protoplasts of epiderma and sub-epidermal sclerenchyma cells. The localization of the pigment suggests that melanin may perform some protective or sunlight-to-heat transforming function. Full article

Nowadays, due to strategic reasons such as the importance of energy and environmental protection, the demand for alternatives to fossil fuels has surged. Hydrogen is considered a suitable and potential alternative energy source, promoting the development of various production technologies. However, conventional technologies for hydrogen production generate a large amount of CO₂ greenhouse gases, contributing to serious environmental issues. In recent decades, TiO₂ nanotubes have emerged as effective photocatalysts for electrode reactions involving water splitting, resulting in hydrogen production. These photocatalysts utilize readily available resources: water as the raw material and sunlight as the energy source. Despite their potential, TiO₂ nanotubes face substantial challenges, including a large energy gap resulting in very low electrical conductivity, along with the recombination of electrons and electron holes during the water splitting reaction. These issues present considerable obstacles to the integration of these materials into the industrial cycle of new energy production, particularly hydrogen generation. Currently, the challenges and potential solutions associated with TiO₂ have made it one of the most extensively researched materials worldwide. In this review, the status of photocatalysts based on TiO₂ nanotubes is examined, highlighting the main challenges in this field and the proposed solutions to address these obstacles. Full article

Personal protective equipment (PPE) like single-use face masks is discarded after a single use and poses a significant danger to the environment, resulting in plastic pollution. Most of the face masks are made from synthetic polymers and are non-biodegradable to the environment; hence, concerns are being raised about polymers’ environmental impact. Most of the previous studies so far focus on polypropylene (PP) disposable masks and limited data related to environmental abiotic degradation behavior. There is a lack of studies aiming to understand the degradation behavior of different masks and the influence of physical-chemical factors. In this paper, we report on the environmental abiotic degradation of cloth, surgical and respirator filter facepiece 1 (FFP1) masks by accelerated artificial weathering. Furthermore, physical-chemical properties of masks were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Thermo Gravimetric Analysis (TGA). The cloth and FFP1 masks are made from polyethylene terephthalate (PET) and surgical masks were made from polypropylene (PP). Masks were exposed to an accelerated weathering test, which simulates the effects of natural sunlight and reproduces the damage caused by weathering elements such as sunlight, rain and dew. Masks were exposed to Ultraviolet radiation (UV) for 120, 240 and 360 h followed by condensation at 50 °C for 4 h. The FTIR results show that PET cloth and FFP1 PET masks are not degrading with the 360 h maximum exposure duration, which is equivalent to ±180 days. The FTIR scan of the PP surgical mask after 120 h of exposure time shows that it was degraded and broken down into fragments. For the PET cloth mask, a 58% reduction in crystallinity and heat of enthalpy was observed after 120 h of exposure. UV exposure causes a chain scission reaction, breaking down the ester bond in the case of the PET cloth mask. In the case of the PET FFP1 mask exposed to UV for 120, 240 and 360 h, a drastic reduction in crystallinity was observed as compared to the neat (original) PET FFP1 mask. Neat PET cloth and FFP1 masks have higher onset and maximum degradation temperatures as compared to the 120, 240 and 360 h UV exposed masks. Neat PET cloth and FFP1 masks have better resistance to thermal degradation. Full article

UVB radiation present in sunlight is the main pro-oxidative and pro-inflammatory factor that reaches human skin cells, including keratinocytes. Therefore, protective compounds eliminating the negative impact of UVB radiation are constantly being sought. This study aimed to estimate the effect of the lipid extract of microalgae Nannochloropsis oceanica (N.o.) on UVB-irradiated keratinocytes. A proteomic approach was used to estimate the proteomic profile of in vitro-treated keratinocytes. The results indicated 270 proteins had significantly altered expression in UVB-irradiated keratinocytes, while the treatment of cells with N.o. extract partially restored the levels of these proteins. Moreover, changes in protein structure resulting from the binding of glutathione (GSH) and thioredoxin (Trx) were also observed. Most of the GSH-modified proteins were involved in GSH or prostaglandin metabolism, while Trx-modified proteins were molecules related to Trx metabolism, as well as antioxidant and anti-inflammatory signaling. The treatment of cells with N.o. extract contributed to reversing the changes in the level of modification in individual proteins. It can be suggested that the lipid components of the microalgae N.o. extract protect keratinocytes against changes in metabolism induced by UVB radiation, modulating the antioxidant and pro-inflammatory responses of cells at the GSH and Trx-based signaling levels. Full article

Benefit/risk management of skin exposure to sunlight, especially ultraviolet (UV) rays, is mainly driven by photoaging, cancer incidence, and the requirement for vitamin D3 synthesis. Antioxidant phytocompounds are considered to be a valuable source of molecules to protect skin from UV-induced damage, but their impact on other UV-related metabolic pathways is rarely described. In this study, an indigoid-rich Persicaria tinctoria extract (PTE) was evaluated on three consequences of UV exposure: DNA damage and inflammation, vitamin D3 content, and melanogenesis. A moderate UV exposure was applied on skin models, corresponding to approximately 1 h exposure in the spring in western Europe. UV-induced DNA damage and inflammation were measured through the quantification of cyclobutane pyrimidine dimers (CPDs) and cytokines. Response to heat stress was quantified through the release of prostaglandin. Then, the impact of PTE on vitamin D3 and melanin synthesis was observed. PTE decreased by −56% in the number of cells presenting CPDs. PTE decreased the production of pro-inflammatory cytokine IL-6 (−59%) and stimulated the release of the protective cytokine IL-1Ra (+49%). It decreased PGE₂ release by −27%. In skin explants, PTE boosted the vitamin D3 concentration (+345%). Several genes involved in melanogenesis were up-regulated by PTE (MC1R × 2.46, MITF × 1.69, TYR × 2.06, MLPH × 1.53). It promoted melanin content by +126% and by +86% when associated with SPF 30. The extract decreased the amount of protective eumelanin, leading to visible skin tanning of reconstructed human epidermis (L*-15%, ITA −125%). As a new finding, PTE minimized DNA damage and inflammation caused by a daily dose of UV, and surprisingly, promoted vitamin D3 and eumelanin synthesis, suggesting that it represents an opportunity to reconcile skin protection and the physiological need for sunlight. Full article

In South Korea, sunlight rights and daylight rights are legally distinguished, yet no standardized methodology exists for their quantitative assessment. Current evaluations of sunlight rights are narrowly defined, relying on the duration of direct solar penetration at the window center during the winter solstice, while excluding reflected and diffuse light. This restrictive approach has led to confusion among both researchers and legal practitioners, as it diverges from daylighting evaluations that account for indoor brightness and energy performance. The recent enactment of regulations to secure solar access in schools has further intensified disputes between educational institutions striving to protect students’ visual comfort and developers seeking to maximize building potential. To address this gap, this study proposes an evaluation framework tailored to the Korean context. A reference classroom model representative of standard Korean schools was developed, and simulations were conducted by introducing obstructing building masses to block direct sunlight. The methodology evaluated key variables, including time of day and solar altitude, and analyzed daylighting performance and lighting-related energy consumption under obstructed conditions. The results show that blocking sunlight through south-facing windows reduces daylighting performance by 89% to 98%, leading to additional reliance on artificial lighting, with energy use increasing between 128 Wh and 768 Wh. These findings underscore the limitations of current legal interpretations based solely on sunlight duration and highlight the necessity of adopting performance-based evaluation methods. Protecting school sunlight rights through such approaches is essential to enhancing classroom visual environments and reducing energy demand. Full article

Exposure to sunlight, whose main component is UV radiation (UVR), leads to various skin damage such as sunburns, premature aging, or more severe issues such as increased symptoms of autoimmune disease and skin cancer. Therefore, there is a growing interest in developing improved photoprotective agents that can protect skin from sunlight incidence and antioxidants that counteract the oxidative stress caused by it. Lichens are a source of such agents since they adapt to extreme environments including those with high UVR by biosynthesizing metabolites with those properties. In this study, brialmontin 2 (1), physciosporin (2), and pseudocyphellarin A (3) were isolated for the first time from the lichen Pseudocyphellaria berberina (G. Forst.) D. J. Galloway & P. James, along with calycin (4) and 22-hydroxystictan-3-one (5). Their structural characterization was carried out by spectroscopy (¹H and ¹³C NMR). Sun protection factor (SPF) along with critical wavelength (λ_crit), a UVA/UVB ratio (UVA/UVB-r) of one to five, and acetone extract (AE) were evaluated spectrophotometrically as a measure of their UVB and UVA photoprotective capacities, respectively. Additionally, their antioxidant activity was measured by scavenging DPPH free radicals (RSA). Compounds 2, 4, and AE showed “medium” UVB photoprotective capacities (with SPFs between 15 and 30). Additionally, 4 and AE presented “maximum” UVA photoprotective capacities (λ_crit > 370 nm and UVA/UVB-r > 0.8), whereas this activity was “good” for 2 and 3 (λ_crit 350 to 370 nm and UVA/UVB-r 0.4 to 0.6), and “moderate” for 1 (λ_crit 335 to 350 nm and UVA/UVB-r 0.2 to 0.4). All compounds and AE showed antioxidant activity, standing out were AE and 4 with activity comparable to the controls (ca. 95 and 81 RSA %, respectively, at 1000 ppm). AE and 4 are dual agents with photoprotective (UVB-UVA) and antioxidant capacities that could help prevent skin damage associated with sunlight. In silico assays suggest that 4 spontaneously diffuses into the stratum corneum with limited absorption through the skin. Additionally, 4 lacks potential toxicity to Normal Human Epidermal Keratinocytes (showing viability ca. 70% at 100 ppm); therefore, it is a candidate for the development of sunscreen formulations. Full article

Chlorophylls, which are associated with carotenoids and photosynthetic protein complexes, acquire optical properties that enable the absorption of sunlight, necessary for the synthesis of energy and redox equivalents, necessary for photosynthetic absorption of CO₂ and the production of oxygen as an intermediate product. These processes are important for plants, but also for the biosphere. In stressful situations, when photosynthesis is limited, the production of reactive oxygen and other species increases, and the activation of various protective systems is necessary to remove the aforementioned reactive species or reduce the excessive reduction in photosynthetic electron transport, as the cause of the production of the reactive species. A review of studies where the content and physiological state of chlorophyll are monitored, using destructive and non-destructive methods, such as various optical methods for monitoring its content and physiological activity, is given. Polyphenolic compounds belong to non-enzymatic systems for quenching the reactive species. In addition to their presence in monomeric and oligomeric forms of polyphenols, polymerization of this type of compound can occur. In addition to having a protective effect on the plants that synthesize them, polyphenolic compounds also have a beneficial effect on the health of animals and humans who consume them from plants. Full article

Sunlight contains a wide spectrum of radiation from ultraviolet (UV) through visible light to infrared (IR). UV radiation plays a crucial role in skin damage, photoaging, and carcinogenesis, necessitating effective photoprotection strategies. The study evaluated the efficacy of protective lipsticks with different sun protection factor (SPF) values (10, 15, and 30) against UVA and infrared (IR) radiation. In this study, the directional-hemispherical reflectance (DHR) was measured across various spectral bands (335–380 nm, 400–540 nm, 700–1100 nm, and 1000–1700 nm) with SOC 410 Reflectometer (San Diego, CA, USA). Since the device used in this study did not cover the UVB range (290–320 nm), this study does not provide a direct assessment of SPF in its conventional sense. The measurements were taken at four time points up to 120 min after lipstick application. Results indicated that lipsticks with higher SPF values significantly altered skin reflectance in UVA and IR ranges, with SPF30 showing the lowest reflectance in the UVA range (335–380 nm), suggesting greater absorption of UVA radiation by the product and significantly higher reflectance in IR ranges compared to lower SPF lipsticks. Reflectance values generally increased over time post-application for key spectral bands. These findings demonstrate that SPF lipsticks provide variable attenuation of UVA and IR radiation, highlighting their role in comprehensive lip photoprotection. The data support the importance of SPF selection for optimized protection, especially against penetrating UVA and IR components of sunlight. Full article

After heavy snowfall in the Uinta Basin, Utah, elevated surface ozone occurs if a cold-air pool persists and traps emissions from oil and gas industry operations. Sunlight and actinic flux from a high-albedo snowpack drive ozone buildup via photolysis. Snow coverage is paramount in initiating the cold pool and driving ozone generation. Its depth is critical for predicting ozone concentrations. The Basin’s location leeward of the Wasatch Mountains provides conditions for a precipitation shadow, where sinking air suppresses snowfall. We analyzed multiple years of ground-based snow depth measurements, surface ozone data, and meteorological observations; we found that ozone levels track with snow coverage, but diagnosing a shadow effect (and any impact on ozone levels) was difficult due to sparse, noisy data. The uncertainty in linking snowfall variation to ozone levels hinders forecast quality in, e.g., machine-learning training. We highlight the importance of a better understanding of regional variation when issuing outlooks to protect the local economy and health. A wider sampling of snow depth across the Basin would benefit operational forecasters and, likely, predictive skill. Full article

Background/Objectives: Intrinsic biomarkers, such as serum vitamin D levels and the conjunctival ultraviolet autofluorescence (CUVAF) area, have been proposed to quantify sunlight exposure. Evidence suggests that reduced outdoor activity during the SARS-CoV-2 pandemic accelerated the progression of myopia; however, there is little information on the impact of such restrictions on vitamin D levels and CUVAF area in populations with myopia. This study aims to assess the association between serum vitamin D levels and conjunctival ultraviolet autofluorescence area (CUVAF) in young adults with myopia during and after the pandemic, as well as its relationship with sun exposure habits and the use of skin protection measures. Methods: A prospective observational study was carried out. A total of 59 students participated, 32 with a diagnosis of myopia and 27 controls, during SARS-CoV-2 pandemic. Two serological tests for total 25-hydroxy vitamin D (D2 + D3) (Calciferol) were taken, activity habits and sun exposure were identified using the Intermountain Live Well Institute tool, and CUVAF images were taken post-pandemic. Results: In the 59 participants, we observed similar vitamin D concentrations between the myopic and control groups during and after the pandemic. However, analysis of CUVAF areas after the pandemic revealed that myopes had significantly smaller areas compared to controls (p < 0.05). Conclusions: The study demonstrated that using vitamin D as a biomarker for outdoor activity requires additional investigation; the CUVAF biomarker showed a significant association with myopia. Full article

Picea neoveitchii Mast., a critically endangered spruce species endemic to China, is classified as a national second-level key protected wild plant and listed as critically endangered (CR) on the International Union for Conservation of Nature (IUCN) Red List. Its habitat features complex forest light environments, and global climate change coupled with environmental pollution has increased regional nitrogen deposition, posing significant challenges to its survival. This study explores the effects of light–nitrogen interactions on the leaf functional traits of Picea neoveitchii Mast. seedlings by simulating combinations of light intensities (100%, 70%, and 40% full sunlight) and nitrogen application levels (0, 10, and 20 g N·m ⁻²·a⁻¹, where g N·m⁻²·a⁻¹ denotes grams of nitrogen applied per square meter per year). We examined changes in morphological traits, anatomical structures, photosynthetic physiology, and stress resistance traits. Results indicate that moderate shading (70% full sunlight) significantly enhances leaf morphological traits (e.g., leaf length, leaf area, and specific leaf area) and anatomical features (e.g., mesophyll tissue area and resin duct cavity area), improving light capture and stress resistance. Medium- to high-nitrogen treatments (10 or 20 g N·m⁻²·a⁻¹) under moderate shading further increase photosynthetic efficiency, stomatal conductance, and antioxidant enzyme activity. According to the comprehensive membership function evaluation, the L2N0 (70% full sunlight, 0 g N·m⁻²·a⁻¹) treatment exhibits the most balanced performance across both growth and stress-related traits. These findings underscore the critical role of light–nitrogen interactions in the growth and adaptability of Picea neoveitchii Mast. leaves, offering a scientific foundation for the conservation and ecological restoration of endangered plant populations. Full article

Background/Objectives: Adequate vitamin D levels are essential for various physiological functions, including cell growth, immune modulation, metabolic regulation, DNA repair, and overall health span. Despite its proven cost-effectiveness, widespread deficiency persists due to inadequate supplementation and limited sunlight exposure. Methods: This systematic review (SR) examines the relationship between vitamin D and the reduction of cancer risk and mortality, and the mechanisms involved in cancer prevention. This SR followed the PRISMA and PICOS guidelines and synthesized evidence from relevant studies. Results: Beyond genomic actions via calcitriol [1,25(OH)₂D]-receptor interactions, vitamin D exerts cancer-protective effects through mitigating inflammation, autocrine, paracrine, and membrane signaling. The findings reveal a strong inverse relationship between serum 25(OH)D levels and the incidence, metastasis, and mortality of several cancer types, including colon, gastric, rectal, breast, endometrial, bladder, esophageal, gallbladder, ovarian, pancreatic, renal, vulvar cancers, and both Hodgkin’s and non-Hodgkin’s lymphomas. While 25(OH)D levels of around 20 ng/mL suffice for musculoskeletal health, maintaining levels above 40 ng/mL (100 nmol/L: range, 40–80 ng/mL) significantly lowers cancer risks and mortality. Conclusions: While many observational studies support vitamin D’s protective role in incidents and deaths from cancer, some recent mega-RCTs have failed to demonstrate this. The latter is primarily due to critical study design flaws, like recruiting vitamin D sufficient subjects, inadequate dosing, short durations, and biased designs in nutrient supplementation studies. Consequently, conclusions from these cannot be relied upon. Well-designed, adequately powered clinical trials using appropriate methodologies, sufficient vitamin D₃ doses, and extended durations consistently demonstrate that proper supplementation significantly reduces cancer risk and markedly lowers cancer mortality. Full article

The marine habitats of the world’s oceans are being driven beyond their resilience. The ongoing biodiversity crisis is happening fast, within the lifespan of researchers trying to produce the information necessary for the conservation of habitats and marine ecosystems. Here, we report on the destruction of sciaphilic sessile communities and coralligenous concretions produced by the anchoring of a high-tonnage vessel inside a Marine Protected Area in Cyprus. The damage from the anchors and the chains consisted of the dislodgement of large boulders that were dragged or rolled over the seafloor, increasing the breakage and further dislodgement of more boulders; many were left upside-down. The biological communities that thrived in the dark environments below the boulders were directly exposed to high irradiance levels and went through a slow mortality and decaying process, most probably due to a combination of several deterioration agents, such as exposure to direct sunlight, predation, mucilage aggregates, and cyanobacterial blooms. The enforcement of regulatory measures for anchoring and transit in the MPA is necessary to prevent similar destruction. Given the extent of the irreversible damage to these sciaphilic communities, our study is, unfortunately, another environmental post-mortem contribution. Full article

Humans are continuously exposed to blue light from sunlight, computers, and smartphones. While blue light has been reported to affect living organisms, its role in fat synthesis and weight changes remains unclear. In this study, we investigated the effects of prolonged blue light exposure on weight changes in mice and the protective role of tranexamic acid (TA). Mice were exposed daily to blue light from a light-emitting diode for five months. Blue light exposure led to increased fat mass and body weight. The expression of the clock genes arnt-like 1 (Bmal1) and Clock was reduced in the brain and muscle of exposed mice. In addition, reduced Sirt1 and increased mammalian target of rapamycin complex 1 (mTORC1)/sterol regulatory element-binding protein 1 (SREBP1) were observed. The levels of liver X receptor a and liver kinase B1/5′AMP-activated protein kinase a1, both involved in SREBP1-mediated lipogenesis, were also elevated. TA treatment prevented the blue light-induced suppression of Bmal1/Clock and modulated the subsequent series of signal transduction. These findings suggest that prolonged blue light exposure suppresses the clock gene Bmal1/Clock, reduces Sirt1, and activates lipogenic pathways, contributing to weight gain. TA appears to regulate clock gene expression and mitigate blue light-induced weight gain. Full article