Search Results (723)

Background/Objectives: DNA methylation is a key epigenetic modification involved in regulating many cellular processes, including gene expression and the maintenance of genome stability. Ultraviolet (UV) radiation induces DNA damage in the form of pyrimidine-pyrimidone (6-4) photoproducts [(6-4)PPs] and cyclobutane pyrimidine dimers (CPDs), which can lead to mutations if not efficiently repaired. While cytosine methylation has been implicated in influencing UV-induced DNA damage formation, the effect of DNA methylation modulators such as S-adenosyl-L-methionine (SAM) and RG108 on UV damage formation and repair remains unclear. Methods: Here, using immunoslot blot assays, we investigated the effects of SAM and RG108 on UV-induced DNA damage formation and repair in human lymphoblastoid cells. Results: We found that SAM, but not RG108, rapidly suppresses the formation of both (6-4)PP and CPD, with detectable effects within minutes of exposure. Although SAM pretreatment was associated with modestly accelerated early (6-4)PP repair, this effect was accompanied by substantially lower initial damage levels. When cells were treated with SAM or RG108 immediately after UV irradiation to ensure equivalent initial damage burden, no significant differences in repair were observed for either lesion type, demonstrating that the accelerated early (6-4)PP repair reflects reduced lesion burden rather than increased intrinsic nucleotide excision repair (NER). Global 5-methylcytosine (5mC) levels remained stable following SAM or RG108 treatment and during UV damage repair, suggesting that these effects occur independently of global alterations in DNA methylation. Conclusions: Together, our findings reveal that SAM modulates UV damage susceptibility at the level of lesion formation without altering repair, highlighting a previously unrecognized role for DNA methylation modulators in regulating genome stability. Full article

This work analyses the influence of hydrothermal treatment (steaming) on the color stability and photochemical degradation of beech wood (Fagus sylvatica L.) with false heartwood under the influence of UV radiation. Samples in the native state and after steaming at temperatures of 105 °C (Mode I) and 120 °C (Mode II) were exposed to simulated aging in a Xenotest device for 360 h. Color changes were assessed in the color space CIE L*a*b* and surface chemical changes using ATR-FTIR spectroscopy. The results showed that unsteamed wood darkens significantly under the influence of UV radiation (ΔL* = −10.2), while wood steamed at 120 °C shows the opposite trend—lightening (ΔL* = +8.8). The color difference ΔE* reached values of 12 to 16 units for unsteamed wood, which indicates a complete color change. Steaming at higher temperatures successfully homogenizes the color of the sapwood and false heartwood and ensures their subsequent uniform visual aging. Full article

As one of the core technologies in modern national defense and security fields, infrared stealth technology aims to realize the controllable regulation of the radiation characteristics of targets in the infrared band. This paper focuses on a novel electrochromic device with a structure of WO₃/nickel mesh/Al³⁺-Zn²⁺gel electrolyte/zinc foil. The structural composition and working mechanism are systematically analyzed, and the infrared stealth regulation performance is emphatically studied. The WO₃ thin film and device structure were characterized by scanning electron microscopy (SEM). The infrared emissivity modulation and optical response properties of the device were measured using an infrared thermal imager and a UV-Vis-NIR spectrophotometer. The prepared WO₃ film exhibits a dense spherical morphology, indicating excellent uniformity and compactness. After 1000 cycles, the areal capacitance of the device remains 83.7% of its initial value, demonstrating good cycling stability. Under the voltage regulation of −0.1 V to 1.1 V, the emissivity ε of the device at the typical mid-wave infrared wavelength of 4.0 μm decreases from 0.89 (−0.1 V) to 0.67 (1.1 V), with an absolute modulation amplitude Δε of 0.22. At the typical long-wave infrared wavelength of 8.7 μm, ε decreases from 0.96 (−0.1 V) to 0.69 (1.1 V), with an absolute modulation amplitude Δε of 0.29. The electrochromic switching times for coloring and bleaching are 10.1 s and 2.44 s, respectively. According to infrared thermal imaging tests, in the temperature range of 30–40 °C, the surface temperature difference ΔT between the colored state and bleached state increases from 4.3 °C to 4.6 °C. The maximum regulation amplitude reaches 4.6 °C at 40 °C. The device achieves efficient regulation of infrared emissivity through the electrochromic effect, providing a new device design strategy for infrared stealth technology. Full article

In this study, kefir production was investigated using both commercial kefir cultures and kefir grains, with milk treated at different UV-C doses and flow rates. The flow rate was set to 25 or 50 mL/min, and doses of 43.2 and 21.6 J/mL were applied at each flow rate, respectively. In all samples subjected to UV-C treatment, pH values decreased during storage, while % titratable acidity values increased. The kefir samples produced with UV-C-irradiated milk showed increased hardness and consistency, while cohesion and the index of viscosity decreased. The highest effect was observed in samples produced with kefir grain and at a flow rate of 50 mL/min. Lactic acid bacteria, Streptococcus/Lactococcus, and yeast counts in kefir samples produced from UV-C-treated milk increased. Flow rate affected the increase in microorganism counts. The physicochemical, textural, and microbiological changes during storage were more pronounced in kefir samples produced with kefir grains than with powdered cultures. The organic acid levels of kefir samples produced from milk treated with UV-C decreased compared to those of control samples. Furthermore, organic acid values increased during storage in all samples. As the flow rate increased, the amount of organic acids formed decreased (except for malic and formic acid levels). Full article

Armoracia rusticana (horseradish) is rich in bioactive compounds such as glucosinolates, phenolic compounds, and vitamin C, highlighting promising potential for innovative food applications, while its use in food packaging materials remains largely unexplored. This study aimed to evaluate how the concentration of horseradish root powder affects the properties of novel bioactive membranes formulated with sodium alginate, glycerol and soy lecithin. The physicochemical, mechanical, barrier and optical properties of the membranes, as well as their specific antioxidant and antimicrobial capacity, were investigated. The structure of the membranes was analyzed in terms of the functional groups and the possible interactions between the polymer matrix components using FT-IR analysis. Alongside microscopic observation of the membrane surfaces at 40× magnification, the roughness of the membranes was investigated, as well as the influence of parameters corresponding to the homogeneity and uniformity of the developed edible food membranes. The results show significant differences in the determined properties, highlighting good barrier capacity against water vapor and UV radiation, as well as high tensile strength and elongation at break values of 17.54 ± 1.18 N and 65.6 ± 9.63%, respectively. Values progressively increase as the content of incorporated plant material rises. The addition of horseradish positively influenced the composition of the membranes, increasing their antioxidant activity values by up to 34.92 ± 0.06%. Full article

Short-wavelength ultraviolet radiation can impair biological systems by causing DNA damage, oxidative stress, and disruption of photosynthetic processes. Although ultraviolet C (UVC) at 254 nm is widely used as a controlled laboratory stressor, the extent to which trophic condition influences repeated UVC tolerance in phototrophic protists remains unclear. Here, we examined the response of Euglena gracilis grown under photoautotrophic or ethanol-supported mixotrophic conditions and exposed to daily UVC pulses for five days. Cell growth, photosynthetic pigments, intracellular oxidative stress measured by 2′,7′ dichlorodihydrofluorescein diacetate fluorescence, and lipid peroxidation estimated as thiobarbituric acid reactive substances equivalent malondialdehyde were assessed, together with qualitative fluorescence microscopy. Repeated UVC exposure reduced cell density in both trophic conditions, with stronger inhibition under photoautotrophy. Photoautotrophic UVC-treated cultures showed the highest oxidative stress signal, whereas malondialdehyde displayed only a non-significant directional increase. Mixotrophic cultures maintained higher cell density under UVC and showed lower oxidative stress signals than photoautotrophic UVC-treated cultures. Pigment responses also differed between trophic conditions, with increased chlorophyll a and carotenoids per cell under photoautotrophic UVC treatment, while mixotrophic pigment levels remained comparatively stable. These findings show that trophic condition shapes repeated UVC stress responses in E. gracilis and that ethanol-supported mixotrophy is associated with improved physiological robustness under the present experimental conditions. Full article

Skin cancer is the most common cancer worldwide, with ultraviolet radiation (UVR) being a major risk factor. Excessive UVR exposure can damage the skin and eyes, making it essential to monitor the Ultraviolet Index (UVI). However, few affordable devices are available for this purpose, limiting public awareness. This study presents the development, calibration, and experimental validation of a low-cost UVI monitoring device against a professional radiometer. The prototype was deployed in Campina Grande, Paraíba, Brazil, and its measurements were systematically compared with data from a nearby automatic meteorological station. The device, based on the UVM-30A sensor, measures UV radiation and transmits UVI values via a mobile application and a public display. Statistical analysis showed strong agreement with reference data, where Pearson Correlation Coefficient r = 0.849 (R² = 0.721 and RMSE = 1.26), and Confidence Index c = 0.917. The device provides an accessible tool for real-time UVI monitoring, promoting public awareness of solar radiation risks and supporting public photoprotection policies. Full article

The chlorophyll molecule is considered a low-cost material, easy to synthesize, and easily extracted from plant leaves. It exhibits high chemical stability, structural flexibility, and high absorbance ability at the visible range of electromagnetic radiation. In this work, the geometrical, electronic, and optical properties of pure, dissolved, and doped chlorophyll (C1) natural organic dye were computed by density functional theory (DFT) and time-dependent density functional theory (TD-DFT). The solvents considered include water (H₂O), acetone (C₂H₆O), dichloromethane (CH₂Cl₂), chloroform (CH₃Cl), and dimethyl-sulfoxide (DMSO) (C₂H₆OS). The solar photovoltaic parameters, such as light-harvesting efficiency (LHE), oscillation strength (f), free energy of electron injection (${\Delta \mathrm{G}}_{\mathrm{I}\mathrm{n}\mathrm{j}.}$) and regeneration (${\Delta \mathrm{G}}_{\mathrm{R}\mathrm{e}\mathrm{g}.}$), open-circuit voltaic (V_OC), and efficiency ($\eta$), were also investigated. The evaluated energy gap slightly shifted from 1.920 eV to 1.980 eV based on the solvent polarity, while the UV-Visible absorption spectrum red-shifted from 422.3 nm to 439.8 nm, improving the overall efficiency up to 21.5% in DMSO solvent. The (LHE) and (${\Delta \mathrm{G}}_{\mathrm{I}\mathrm{n}\mathrm{j}.}$) properties regarding Cl molecules improved up to 69.1% and −1.384 eV when dissolved in chloroform and DMSO solvents, respectively. Doping C1 molecule via metal transition atoms such as zinc (Zn), nickel (Ni) and copper (Cu) further modified the optical and photovoltaic performance. Doped C1 molecule via Cu atom shows the best photonic results, including the highest open-circuit voltage (V_oc) and conversion efficiency ($\mathrm{Ƞ}$), while the Ni-doped C1 dye displays the longest lifetime, 1.699 µs, and the highest electronic coupling constant, 1.975 eV; thus, it has the superior photovoltaic performance. These results demonstrate that both solvents and transition metal atom modification significantly improve C1 performance, making metal-doped C1 a promising low-cost and eco-friendly sensitizer for dye-sensitized solar cells (DSSCs). Full article

Forest waste is globally abundant and holds significant potential for valorisation in various sectors. This paper investigates its use in urban road infrastructures, utilising enzymatic lignin, a by-product from forest waste bioethanol production, as a bitumen extender for warm-mix asphalt. Since this asphalt concrete is produced at about 40 °C below the traditional hot-mix asphalt temperature, this study evaluates lignin’s ability to ensure the required mechanical performance of asphalt concrete in both aged and non-aged states. The TEAGE—TEcnico accelerated AGEing device—applied UV radiation and wet/dry cycles to virgin bitumen, a lignin blend, and compacted asphalt concrete specimens to replicate urban weathering. Cylindrical specimens underwent indirect tensile tests to assess water sensitivity, while beam samples underwent four-point bending tests to evaluate stiffness and fatigue resistance. The results indicate that this warm-mix asphalt, with lower atmospheric emissions during manufacturing and pavement construction, meets the mechanical demands of urban roads, particularly with respect to fatigue and water resistance. However, the findings also show that asphalt concrete containing lignin experiences excessive ageing of small specimens, and further testing on compacted slabs is needed to better simulate exposure to UV radiation in pavement layers. Overall, the study concludes that lignin lowers asphalt production temperatures and partially substitutes conventional binders, with promising applications in urban pavement technologies. Full article

Background/Objectives: Atypical fibroxanthoma (AFX) and cutaneous undifferentiated pleomorphic sarcoma (cUPS)/pleomorphic dermal sarcoma (PDS) are related dermal neoplasms of uncertain histogenesis that occupy opposite ends of a shared clinical and histopathologic spectrum, with AFX displaying typically low-grade behavior and PDS representing its more aggressive counterpart. The recent literature has confirmed that AFX and PDS also overlap at the molecular and genomic levels; however, little is known about their gene-expression profiles. Methods: We performed gene-expression profiling using RNA sequencing with a Pan-Cancer RNA Panel on a small series of AFX and PDS samples. Results: Unsupervised cluster analysis showed a clear separation between the two groups. We confirmed a TP53 UV-radiation signature in both. However, while AFX and PDS share common DNA mutation profiles in our cohort, RNA sequencing reveals distinct gene-expression signatures that may aid in differentiating these related tumors. In particular, the MAPK pathway, cell adhesion, DNA repair, EMT-like signatures and inflammatory responses play key roles in distinguishing the two groups, at least in our limited cohort, consistent with their differing biological behavior. Differences in the expression of receptor tyrosine kinases were also observed. Conclusions: Gene-expression profiling have the potential to be a valuable tool for distinguishing AFX from PDS, clarifying their positions at opposite ends of a spectrum and providing deeper insight into the biology of these neoplasms. Full article

Ultraviolet-B (UV-B) radiation plays a pivotal role in plant growth, metabolism, and the accumulation of bioactive compounds, but its effects under greenhouse conditions are highly species- and dose-dependent. This study investigated the responses of eggplant (Solanum melongena L., cv. Lunga Napoletana) and lettuce (Lactuca sativa L., cv. Rosplus) cultivated under greenhouse films transmitting 3–39% of ambient UV-B. Leaf temperature was monitored throughout the growth cycle using infrared thermography, while physiological parameters (chlorophyll, flavonoids, anthocyanins, and nitrogen index) and post-harvest nutritional traits (antioxidant activity, vitamin C, carotenoids, and total chlorophyll) were assessed. Comparative analysis revealed species-specific responses. Eggplant exhibited peak nutraceutical quality at higher UV-B levels (35–39%) with minimal changes in yield, whereas lettuce achieved maximal yield and secondary metabolite accumulation under intermediate UV-B (30–35%). At the highest UV-B transmittance (39%), both species exhibited stable or slightly reduced thermal and physiological parameters, indicating dose-dependent regulatory mechanisms that maintain photoprotection and metabolic activity under elevated UV-B exposure. Results suggest an apparent optimal range of UV-B transmittance in greenhouse systems under the tested experimental conditions, contributing to improved crop productivity and nutritional quality. Full article

The skin, the largest organ in the human body, serves as a crucial barrier against external stimuli. With the acceleration of social industrialization and the worsening of global climate change, the risk of physical, chemical and biological damage to the skin has significantly increased. Among these, surgical wounds, accidental injuries, diabetic wounds, and ultraviolet (UV)-radiation-induced photoaging are particularly common. Cutaneous wound healing is a complex and dynamic process that requires precise coordination of numerous molecular events to effectively repair damaged skin. Skin photoaging, a phenomenon of premature aging caused by long-term UV exposure, is characterized by pigmentary abnormalities, telangiectasia, epidermal roughness, wrinkle formation, and precancerous lesions, all of which seriously affect skin health and appearance. Extracellular vesicles (EVs), a class of nano-sized vesicles secreted by various cells, play important regulatory roles in tissue regeneration. Although cell-culture-medium-derived EVs (C-EVs) have been proven to effectively promote skin wound healing and photodamage repair, their origin from a single cell type and challenges in large-scale production severely limit their broad application. In contrast, EVs derived from natural biological resources, including tissue-derived EVs (Ti-EVs) and plant-derived EVs (PDEVs), have emerged as novel therapeutic strategies for skin wounds and photoaging. These EVs better reflect the physiological microenvironment and demonstrate considerably higher production efficiencies. Ti-EVs, obtained from mammalian tissues composed of multiple cell types and extracellular matrix, contain more abundant regulatory factors, thus exhibiting superior bioactivity compared with C-EVs. PDEVs have also garnered significant attention due to their favorable stability, low immunogenicity, unique natural antioxidant components, and feasibility of large-scale extraction. This review will systematically elaborate on the characteristics and isolation methods of both Ti-EVs and PDEVs, as well as their therapeutic roles and underlying mechanism in wound healing and skin photoaging. Full article

The use of microalgae as a food source is limited by consumers’ dislike of their organoleptic traits, primarily the intense green color and bitter taste associated with high chlorophyll content. The eukaryotic microalgae Chlorella vulgaris can grow under heterotrophic conditions, providing the opportunity to cultivate chlorophyll-less strains. In this work we applied random mutagenesis for breeding chlorophyll-deficient C. vulgaris strains. Wild-type strain was UVC-radiated, and 12 colonies with changed pigmentation were selected. Based on phenotypic stability two mutants, M6 and M11, were selected for characterization of growth, pigment and biomass accumulation. Cultivation under photo-, mixo- and heterotrophic conditions revealed distinct phenotypes for the two mutants. M6 remained chlorophyll-deficient in all cultivation conditions tested, while chlorophyll was observed in M11 when grown under light. Under heterotrophic and mixotrophic growth conditions, both mutants were chlorophyll-deficient while biomass productivity, protein content, and amino acid composition remained similar to wild type. Characterization of the cellular ultrastructure of the wild type and mutants using cryo Focused Ion-Beam Scanning Electron Microscopy revealed that functional chloroplasts and thylakoid membranes were absent in the mutants. Our work demonstrates how a simple approach using UV mutagenesis and visual screening can provide novel strains of C. vulgaris with traits for improved consumer acceptance, without compromising the use of the algae biomass as a protein-rich food source. Full article

Artificial optical radiation, spanning from 100 nm to 1 mm, encompasses ultraviolet (UV) and infrared (IR) light. UV light is well known for its risks on the skin and eyes. Recently, there has been growing interest in light at 405 nm (violet-blue light, VBL) due to its antimicrobial properties and perceived safety for mammalian cells when administered in controlled amounts. This research delved into the impact of 405 nm VBL on corneal and retinal pigment epithelial cell cultures. ARPE-19 and corneal BCE C/D 1b cells were exposed to VBL for varying doses, according at different exposure times, to evaluate cell viability, oxidative stress levels and apoptotic indicators. A 3D printed prototype with 14 LEDs centred at 405 nm wavelength was used to ensure uniform distribution of light during exposure. Cell viability was assessed using the MTT assay, measurement of oxygen species (ROS) production was carried out, and Western blot analysis was employed to study catalase and SOD-1 expression and apoptotic marker activation. Exposure to 405 nm VBL for both term (3 h) and prolonged durations (9 h) led to a weak decrease in cell viability in ARPE-19 cells, whereas the effect on BCE C/D 1b cells was negligible. There was no increase in ROS production, with catalase and SOD-1 expression remaining stable, suggesting no pro-oxidative stress effects in these models. Moreover, no activation of caspase-3 and accumulation of cytochrome C were found. Based on our results, exposure to 405 nm light at regulated levels does not pose a threat to the viability of the tested cell lines and does not lead to oxidative stress and apoptosis under these conditions. These results suggest a favourable cytocompatibility profile for these specific ocular cell models, laying a foundation for further investigations into its ocular safety. Full article

Human rhinovirus (HRV) is one of the common respiratory viral infection agents that triggers airway obstruction and asthma exacerbations, especially during childhood. This project aimed at evaluating the mechanism of ultraviolet (UV) and infrared (IR) radiations to inactivate HRV infection and replication inside and outside infected airway epithelial cells and the resulting impact on interferon responses and epithelial barrier integrity. Hereby, airway epithelial cells were infected with different RV concentrations. Later these cells are exposed to UV and IR light to analyze their impact on the viral immune response of the host by real-time PCR. It was found that RV1B disrupted cell junctions of airway epithelial cell barriers. Moreover, high doses of RV1B activated pattern recognition receptor (TLR3), induced interferon (IFN-β) response and reduced SOCS1, which is a negative regulator of IFN-β. Further, IR lights inhibited rhinovirus post infection in primary nasal epithelial cells (NECs). Finally, UVC exposure significantly inhibited the antiviral effects of the host via SOCS1 inhibition and decreased RV1B within 72 h. Collectively, these findings support the role of UV light as an effective therapeutic approach for acutely eliminating RV but resulting in barrier and antiviral damage, which can have a drawback effect for asthma. Full article