Search Results (2,098)

The ionosphere is the ionized region of the atmosphere, extending roughly from 60 km to 1000 km in altitude. During flares, the near-Earth space is subjected to high-energy X-ray and EUV (extreme ultraviolet radiation) radiation, which also impacts the ionosphere. The changes in the ionospheric parameters measured by ionosondes, namely the f_min (minimum frequency) and foF2 (F2-layer ordinary-mode critical frequency) values, were examined during solar flares that occurred in geomagnetically quiet conditions (Dst (Disturbance Storm Time index) > −40 nT, Kp (planetary K-index) < 4). The necessary data were obtained by manually evaluating ionograms recorded by the Czech DPS4D ionosonde at Pruhonice (PQ052). The degree of variation was compared to quiet reference days, allowing for the determination of the deviations in the required values (df_min, dfoF2). The time series of the deviations were investigated. Furthermore, the relationship between the deviations and a “geoeffectiveness” parameter of the solar flare was also examined. The X-ray flux, the solar zenith angle of the station at the time of the event, and the position of the flare on the solar disk were also taken into account for the determination of the “geoeffectiveness” parameter. A positive correlation was observed between df_min and the geoeffectiveness parameter of the flare, which was more significant than the correlation between the dfoF2 and the geoeffectiveness parameter. Full article

Systemic lupus erythematosus (SLE) is a prototypic systemic autoimmune disorder arising from the convergence of genetic susceptibility, epigenetic remodeling, environmental exposures, and dysregulated immune networks. Although traditionally characterized by autoantibody production and immune complex mediated tissue injury, advances in genomics, systems immunology, and multi-omics profiling have revealed that lupus represents a multilayered failure of immune homeostasis driven by interconnected molecular circuits. Genetic variants enriched in regulatory immune enhancers establish a permissive transcriptional landscape that sensitizes innate nucleic acid sensing pathways and interferon signaling. Epigenetic remodeling further amplifies inflammatory transcriptional programs, while environmental triggers such as ultraviolet radiation and viral infection initiate bursts of nucleic acid release and immune activation. Defective apoptotic cell clearance, mediated in part by scavenger receptor dysfunction and complement abnormalities, increases the availability of immunogenic nucleic acids that engage pattern recognition receptors and drive chronic type I interferon production. This interferon-dominated environment rewires immune cell metabolism, alters differentiation trajectories of T and B lymphocytes, and sustains autoreactive immune circuits. Emerging multi-omics studies reveal distinct molecular endotypes defined by interferon signatures, metabolic states, and immune cell composition, highlighting the heterogeneity of disease mechanisms across patients. In this review, we integrate genetic, epigenetic, metabolic, and immunological insights to propose a systems-level model of lupus pathogenesis in which defective debris clearance, nucleic acid sensing, interferon amplification, and metabolic reprograming form a self-reinforcing pathogenic network. Understanding this integrated molecular architecture provides a foundation for biomarker-guided therapeutic strategies and precision medicine approaches aimed at disrupting the key nodes that sustain chronic autoimmunity in SLE. Full article

Background: A compact, in-house-developed ultraviolet germicidal irradiation (UVGI) system using eight 36 W Philips low-pressure mercury UV-C lamps with a peak emission at 253.7 nm was developed for effective sterilization of bacteria and fungi using a wireless mode of operation. Methods: Under controlled laboratory conditions, the system was tested against representative biofilm-forming microorganisms, including Bacillus subtilis, Escherichia coli K12, and a multidrug-resistant Candida albicans M-207 isolate. Microbial viability was assessed using colony-forming unit (CFU) enumeration and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, with structural changes analyzed by scanning electron microscopy (SEM). Cultures were exposed to 253.7 nm UV-C radiation at distances of 1–5 m for 15–90 min. Results: UV-C exposure resulted in time- and distance-dependent reductions in viable counts for all tested organisms, as determined by CFU analysis. At 1 m and 15 min exposure, viable counts for all tested organisms were reduced below the limit of detection (LOD) of the CFU assay, indicating substantial microbial inactivation under the tested conditions. Reduced efficacy was observed at increased distances (3 m and 5 m), with log₁₀ reductions varying depending on organism and exposure conditions. Residual metabolic activity detected by the MTT assay suggests the presence of non-proliferating or damaged cells, consistent with the different endpoints measured by the two assays. The SEM analysis further revealed disruption of biofilm architecture and reduction in cell density with increasing UV dose. Conclusions: The UVGI system demonstrated dose-dependent inactivation of biofilm-forming microorganisms under controlled conditions, supporting its proof-of-concept efficacy. Further studies are required to evaluate performance under real-world conditions. Full article

The interplay between the environmental exposome and the cancer genome remains a critical gap in precision oncology. While somatic mutational signatures—genomic fossils imprinted by exposures such as ultraviolet radiation; tobacco smoke; and industrial pollutants—are well characterised for their etiological significance; their functional impact on therapeutic efficacy remains largely unexplored. We hypothesised that these environmental genomic scars induce distinct pharmacogenomic vulnerabilities and resistance mechanisms that vary by geographical exposure patterns. This study employs two complementary analytical frameworks. First, a linear regression-based pharmacogenomic screen across four datasets (GDSC1, GDSC2, CTRP, CCLE; 1001 cell lines, 31 cancer types) identified 608 statistically significant (p < 0.01) mutational signature–drug interactions, revealing that UV-associated signature SBS7a is associated with broad-spectrum therapeutic resistance, including to BRAF inhibitors (PLX-4720, p < 10⁻⁴), while pollution-driven oxidative stress (SBS18) is associated with sensitivity to p38 MAPK inhibition (VX-702, r = −0.45, p < 10⁻⁹). Second, an XGBoost predictive model trained exclusively on 33,679 GDSC2 records using a 1265-feature matrix integrating 40 SBS signatures, drug chemistry descriptors, proteomic features, and two satellite-derived environmental variables (NASA PM_2.5 and UV)—achieved R² = 0.7973 on a 20% holdout set (grouped cross-validation R² = 0.7296). SHAP analysis revealed that satellite-derived PM_2.5 (Zone_PM25) ranked 7th of 1265 features, exceeding all 40 individual SBS mutational signatures. Synthesising these findings with satellite-derived atmospheric data, we constructed an exploratory spatially interpolated risk surface spanning 122 nations, generating the hypothesis that uniform drug efficacy assumptions may not apply globally. These findings suggest that a patient’s environmental exposure history may constitute a measurable pharmacogenomic variable. This exploratory framework warrants validation in independent datasets and with individual-level geographic data before clinical application. Full article

The aim of this study was to identify and examine materials that have a long history of use in folk medicine and exhibit biological activity but have not been fully utilized. This study evaluated the reactivity of Japanese maca powder in cultured human dermal cells subjected to aging stress (UV irradiation, AGE treatment, or H₂O₂ treatment). The mRNA levels of three stress parameters (collagen, elastin, and hyaluronic acid synthase) were measured using quantitative reverse transcription polymerase chain reaction. The activity of a prototype Japanese maca powder sample was compared with that of samples subjected to fermentation, room-temperature enzyme, and rapid freeze-drying treatments. Inhibitory effects on reactive oxygen species (ROS) were measured, and the expression of genes involved in senescent cell removal (JAG1) and regeneration promotion (EGF) was examined. Finally, the expression of molecules involved in senescent cell phagocytosis (STAB1) and stem cell phagocytosis signaling and regeneration promotion (FGF2) in macrophages was evaluated. The four types of maca samples altered the mRNA levels of the three stress parameters, conferred resistance to various aging stresses, and delayed suppressed intracellular ROS accumulation. These findings suggest that Japanese maca may help to protect skin cells from age-related stress. Full article

Ultraviolet radiation (UVR) exposure accelerates skin aging by disrupting cellular homeostasis and inducing epigenetic changes, such as promoter hypermethylation of key regulatory genes. However, the molecular mechanisms underlying UVR-driven epigenetic silencing remain poorly understood. By integrating high-throughput DNA methylation profiling with co-regulatory network analysis, we identified KIT as a hub gene in a photoaging-associated methylation module. Pathway enrichment further revealed coordinated hypermethylation of the canonical Wnt/β-catenin signaling pathway, establishing the Wnt/KIT axis as a critical epigenetic-signaling nexus in UVR-induced skin fibroblast aging. In immortalized human skin fibroblasts (HSFs), UVR suppressed Wnt signaling, leading to KIT promoter hypermethylation, transcriptional silencing, and premature photoaging. Gain-of-function studies revealed that reversing KIT hypermethylation either via Wnt pathway activation or KIT overexpression effectively mitigated photoaging-associated phenotypes. Crucially, we found that puerarin (PUE), a natural isoflavone, reversed UVR-induced epigenetic silencing by directly interacting with β-catenin, reactivating Wnt signaling, and restoring KIT expression. PUE treatment preserved cellular function in UVR-damaged fibroblasts. These findings establish the Wnt/β-catenin-KIT axis as a critical epigenetic driver of skin aging and highlight puerarin as a promising therapeutic candidate for targeted anti-aging intervention. Full article

(1) The growing interest in the use of natural and sustainable ingredients highlights the investigation of vegetable oils in dermato-cosmetic applications. In this context, the vegetable oil obtained from walnut (Juglans regia L.) is of actual interest due to its composition rich in unsaturated fatty acids. The aim of the present study was to investigate and characterize walnut oil from a physicochemical, structural, and rheological point of view. (2) The oil was obtained by a cold pressing process from walnut seeds, with a yield of about 51.03 ± 1.41%, and subsequently analyzed by complementary methods. (3) The results show an acceptable physicochemical profile, characterized by appropriate values of density, pH, and spreadability. The oxidative stability indicated a moderate resistance to degradation, specific to oils rich in polyunsaturated fatty acids. Fourier infrared transform spectrometry (FTIR) analysis confirmed the presence of functional groups characteristic of triglycerides, without indications of advanced oxidation, and atomic force microscopy (AFM) investigations revealed a heterogeneous morphology. The rheological properties indicated a pseudoplastic behavior, favorable for topical application. The determination of heavy metals confirmed the safety of the raw material for the intended dermato-cosmetic use. While arsenic levels were slightly above the strict Codex Alimentarius limits for foodstuffs, all values remained within the safety ranges established for cosmetic ingredients. A total of six fatty acids were found in cold-pressed walnut oil, determined using GC-MS methods. The number of compounds identified in the silylated sample was found to be 17. The antioxidant activity determined using DPPH and ABTS methods was generally considered good and relatively stable over time. The measured sun protection value (SPF) demonstrates a favorable capacity to act as a photoprotective ingredient against ultraviolet (UV) radiation. (4) Overall, the results demonstrate that walnut oil presents adequate physicochemical and structural properties, supporting its further use as a potential cosmetic raw material. Full article

Background: Ultraviolet-C (UV-C) radiation is a high-energy physical mutagen capable of inducing DNA damage and oxidative stress, thereby generating genomic variability in photosynthetic organisms. However, its genome-wide effects in unicellular eukaryotic microalgae remain poorly characterized. This study developed a UV-C mutagenesis protocol in Chlamydomonas reinhardtii and evaluated its genomic and physiological impacts. Methods: Axenic cultures of Chlamydomonas reinhardtii (137c+) were exposed to UV-C (100–280 nm) for 12, 48, and 96 min. Viable colonies were analyzed by Random Amplification of Polymorphic DNA PCR (RAPD-PCR) to assess genetic variability, while chlorophyll content and the expression of stress-responsive genes were measured via spectrophotometry and Reverse Transcription quantitative Polymerase Chain Reaction (RT-qPCR), respectively. Results: UV-C treatment induced extensive genomic polymorphism with heterogeneous clustering patterns independent of exposure time, consistent with stochastic mutagenesis. Several mutants exhibited reduced chlorophyll content, indicating impaired photosynthetic efficiency. In contrast, one genotype (pop18) maintained wild-type chlorophyll levels despite marked genetic divergence, coupled with upregulation of antioxidant, DNA repair, and stress-response genes. Conclusions: Overall, UV-C irradiation represents an effective approach to generate non-directional genomic variability in Chlamydomonas reinhardtii, with evidence that random mutagenesis can drive functional reorganization of stress-response pathways, supporting its application in microalgal strain improvement. Full article

Recent studies have reported skin microbiome dysbiosis in patients with photodermatoses, featuring enriched Staphylococcus aureus colonization and decreased microbiome diversity. We propose that ultraviolet radiation (UVR), along with atypical antimicrobial peptides, may exert selective pressure on the skin microbiome, while cytokine dysregulation and a reduction in commensal bacteria amplify microbial dysbiosis. Dysbiotic microorganisms further release pathogen-associated patterns and virulence factors, and activate tissue-resident memory T cells, which collectively contribute to local inflammation. These mechanisms establish the skin microbiome as a potential target for early intervention. Potential therapeutic strategies may include antibiotics, phototherapy, bleach baths, phage therapy, and microbiota-based therapies. This review integrates current findings from microbial ecology, molecular biology, and host immunology to outline a conceptual framework linking UVR exposure, microbiome alterations, and cutaneous immune responses, while emphasizing the current limitations and evidence gaps in this field. Full article

Ultraviolet (UV) radiation is a main environmental factor responsible for skin damage, leading to oxidative stress, inflammation, and impairment of the skin barrier function. Furthermore, many components in sunscreen may accumulate in aquatic systems, causing environmental pollution. Therefore, the identification of novel natural bioactives that counteract these effects and can be useful as effective adjuvants in sunscreen formulations is of particular interest. Morin (1), a natural flavonoid, represents an attractive scaffold for modifications to enhance its biological activity. Herein, we aimed to investigate the effects of combining the flavonoid 1 and its derivative, morin semicarbazone (2), with the carotenoid fucoxanthin (FX) on UVB-exposed HaCaT keratinocytes. All compounds exhibited higher radical scavenging activity compared to Trolox. In this cell model, the phenolic–carotenoid combinations provided greater photoprotection than individual compounds, significantly enhancing cell viability and reducing necrosis, FX-2 emerged as the most potent combination, as evidenced by a marked reduction in reactive oxygen species (ROS) and malondialdehyde (MDA) levels, likely mediated through the activation of the nuclear factor erythroid 2-related factor 2/Heme oxygenase-1 (Nrf2/HO-1) signaling pathway. Furthermore, the tested treatments exerted enhanced anti-inflammatory effects by significantly reducing interleukin-6 (IL-6), cyclooxygenase 2 (COX-2), and matrix metalloproteinase-9 (MMP-9) mediators, with FX-2 being the most active combination. In conclusion, our findings highlight the protective effects of the combinations of these phenolics with the carotenoid FX against UVB radiation and support their potential application as natural active ingredients in sunscreen formulations. Full article

Transfer RNA-derived fragments (tRFs) have been recently recognized for their multiple roles in gene expression, including modulation of translation, mRNA stability, and cellular signaling pathways. Sensory organs, such as the eyes, skin, and oral cavity, are continuously exposed to environmental stressors, including oxidative stress, ultraviolet radiation, microbial challenges, and mechanical stimuli, making them particularly susceptible to dysregulation of RNA-mediated processes. This review comprehensively summarizes current evidence on the role of tRFs in sensory organ physiology and pathology with a focus on their involvement in key processes, such as angiogenesis, inflammation, immune regulation, and fibrosis. tRFs have been shown to influence critical signaling pathways that are central to diseases such as retinal neovascularization, inflammatory skin conditions, wound healing, tissue remodeling, etc. Despite these advances, the field remains limited by a lack of experimentally validated tRF-target interactions, as most available data rely on computational predictions. The findings from the literature emphasize the need for rigorous functional validation in disease-relevant models of tRFs in biofluids, such as saliva and serum, to support their potential as minimally invasive biomarkers. Further translational studies are required to fully elucidate their biological roles and explore their potential in diagnostic and therapeutic applications. Full article

The long-term exposure of asphalt pavement to ultraviolet radiation causes significant performance degradation and reduces its service life. To enhance the UV resistance of asphalt, nanocomposite modifiers have been incorporated through mechanical blending. However, their effectiveness has been largely limited by poor component uniformity. To address this issue, UV-resistant antioxidant nano-TiO₂ was employed to modify the UV-shielding of layered porous carbon (PC), resulting in the synthesis of nano-TiO₂ intercalated PC (TiO₂/PC). The PC nanosheet was modified by TiO₂ nanoparticles via in situ growth, significantly improving the dispersion homogeneity of TiO₂. Comprehensive characterization (SEM/EDS/FT-IR/XPS) confirmed the successful synthesis of TiO₂/PC with well-defined interfacial bonding. Compared to control samples (PC, TiO₂, and TiO₂ + PC), the asphalt modified by TiO₂/PC-2 composite demonstrated superior UV aging resistance, lower physical aging indices and reduced rheological aging parameters. Moreover, TiO₂/PC modifier prominently suppressed the formation of oxidative groups (C=O/S=O), improved the colloidal stability, and delayed the sol–gel transition of the modified asphalt. The synergistic UV shielding mechanism was attributed to the enhanced UV absorption of TiO₂, multi-reflection and scattering within the PC matrix, and the radical scavenging capabilities of both components. These results provide new design insights for developing anti-UV aging modifiers for asphalt pavements. Full article

Skin aging is driven by both intrinsic and extrinsic factors, including ultraviolet (UV) radiation and environmental stressors. Tumor necrosis factor-alpha (TNF-α) is a key pro-aging cytokine that promotes reactive oxygen species (ROS) production, leading to collagen degradation and inflammatory responses in skin cells. In this study, we investigated the protective effects of Prunus persica flower extract and its major constituents (1–4) against TNF-α–induced oxidative and inflammatory responses in human dermal fibroblasts (HDFs) and human epidermal keratinocytes (HEKs). In HDFs, the extract and isolated compounds significantly suppressed TNF-α–induced ROS generation and matrix metalloproteinase-1 (MMP-1) secretion while enhancing collagen synthesis. Notably, mandelamide (4) markedly reduced MMP-1 secretion (from 7.53 ± 0.28 to 2.97 ± 0.12, p < 0.001) and restored collagen levels (from 3.3 ± 0.03 to 19.1 ± 0.58, p < 0.001). In HEKs, mandelamide attenuated the production of inflammatory mediators under TNF-α stimulation and further suppressed MMP expression while restoring the mRNA expression of hyaluronan synthase genes under TNF-α/ interferon-γ (IFN-γ) co-stimulation. Importantly, mandelamide exhibited selective activity under inflammatory conditions without affecting basal cellular states. Collectively, these findings demonstrate that mandelamide is a key bioactive constituent of Prunus persica (P. persica) flowers and exerts protective effects against inflammation-associated skin aging through the modulation of oxidative stress and extracellular matrix homeostasis. Full article

Microplastics (MPs), i.e., plastic particles <5 mm, and nanoplastics (NPs), i.e., plastic particles <1 µm, are widespread in the environment. MPs and NPs (MNPs) have also been detected in human tissues. Environmental MNPs exhibit diverse physicochemical properties such as size, shape, and surface degradation. However, most experimental studies have used pristine MNPs, which poorly represent real-world conditions, and only a limited number of studies have focused on preparing environmentally relevant MNPs. Therefore, we focused on the key physicochemical properties of MNPs, particularly their shape, size, and surface degradation, using polyvinyl chloride (PVC) as the model polymer. In this study, fragment and spherical PVC-MNPs were utilized, and surface degradation was introduced through exposure to vacuum ultraviolet (VUV) radiation at a wavelength of 172 nm. Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) analysis revealed the formation of additional carbonyl groups after VUV exposure. We investigated the cytotoxic effects of the degraded and non-degraded PVC-MNPs on A549, Caco-2, and THP-1 cells. The results indicated that the degraded PVC-MNP-treated groups induced higher cytotoxic effects than those in the non-degraded groups. Notably, the degraded PVC-NPs induced stronger cytotoxicity than the degraded PVC-MPs. These findings highlight the potential health risks associated with environmental MNPs. Full article

Wood coatings play a critical role in protecting wood substrates from environmental degradation, particularly ultraviolet (UV)-induced photodegradation. This review comprehensively examines the mechanisms of wood coating photodegradation, the factors influencing their durability, and current anti-aging strategies. Photodegradation arises from polymer chain scission, chemical structure reorganization, and photo-oxidation of lignin and cellulose, leading to coating chalking, cracking, gloss loss, and color changes, ultimately compromising wood mechanical properties and service life. Key anti-aging strategies include UV absorbers, which convert harmful UV radiation into heat; hindered amine light stabilizers (HALSs) that capture free radicals and quench excited-state molecules; barrier and shielding materials that form dense physical or nanostructured networks to block UV penetration and enhance mechanical and water resistance; and antioxidants that neutralize free radicals or decompose peroxides at the molecular level. Each approach can be employed individually or synergistically to enhance coating durability. Challenges remain in achieving long-term outdoor stability, balancing transparency and UV shielding, optimizing nanoparticle dispersion, and maintaining the activity of natural antioxidants. Future research should focus on multifunctional composite coatings integrating bio-based materials and nanotechnology, smart responsive systems, adaptive protection mechanisms, and standardized long-term evaluation protocols. These advancements will facilitate the development of high-performance, sustainable wood coatings and promote the value-added utilization of wood resources. Full article