Search Results (737)

In Chile, Eucalyptus globulus stands out as a significant forest species, yielding around 2 million tonnes of bark; this by-product is a valuable source of phenolic compounds. This research evaluated the valorization of E. globulus bark using alkali-assisted extraction (AAE) and obtained extracts intended to protect the wood against fungal degradation and ultraviolet (UV) radiation. The chemical and thermal properties of the extracts were characterized using total phenolic content (TPC), antioxidant capacity, FTIR spectroscopy, LC-LTQ-Orbitrap-MS, and thermal analyses (TGA and DSC). Pine wood samples were impregnated using the Bethel process, and their absorption, retention, leaching, UV resistance, gloss, and antifungal efficacy were evaluated. The AAE showed an extraction yield of 8.79%, almost double that of aqueous extraction, with a phenolic content of 970 mg GAE/100 g dry bark and good antioxidant capacity. The MS/MS analysis tentatively identified low-molecular-weight organic acids, phenolic acids, a hydrolyzable tannin derivative, ellagic acid, methylated flavonol glycosides, and an iridoid non-phenolic metabolite. Thermal analysis indicated greater stability of the alkaline extracts, with a mass loss of less than 10% up to 200 °C, and significant degradation between 220 and 300 °C. Leaching tests showed a lower release of polyphenols from alkali-treated wood, indicating reduced mobility and/or greater retention of the extractives within the wood structure. Biological assays demonstrated effective inhibition of stain fungi and strong resistance to brown rot. Furthermore, UV aging tests showed less color change (Delta E*) and greater resistance to surface degradation. These results demonstrate the potential of alkaline extracts from E. globulus bark as sustainable additives for wood protection. Full article

The present study was conducted to study the effect of exposure time to ultraviolet-C (UV-C) radiation on seed germination, fungal suppression and seedling growth of three Egyptian rice cultivars, namely, Sakha 105, Sakha 108, and Giza 183. Experiments were carried out under controlled laboratory conditions. Rice seeds were exposed to UV-C radiation with a wavelength of 253.7 nm and intensity of 1960 µW cm² for 0 (control), 10, 20, 30, 40, 50, and 60 min. Initial seed health testing showed the presence of several seed-borne fungi, mainly Alternaria alternata, Rhizoctonia solani, and Fusarium verticillioides, in addition to Aspergillus niger and Aspergillus flavus. Results revealed that UV-C exposure time, rice cultivar and their interactions significantly (p < 0.05) affected germination percentage, reduction percentage of seed fungal infection, and seedling growth parameters. The optimum exposure time was 30 min, which was found to maximize germination and improve shoot and root growth to achieve high levels of fungal suppression. Giza 183 exhibited the highest average germination percentage (92.40%), while Sakha 105 obtained the highest shoot height (17.00 cm) and root length (12.91 cm). The results indicate that UV-C irradiation is an effective, residue-free and environmentally sustainable seed treatment technology for improving rice seed quality as well as early seedling performance. Full article

Heparin is a highly sulphated polyelectrolyte, and its properties depend strongly on its shape in solution. In this study, we closely examined the structural behaviour of low-molecular-weight heparin under aerobic ultraviolet-C (UVC, 100–280 nm) radiation. Using controlled photodegradation, we prepared native, small, and ultra-small molar-mass fractions, enabling us to investigate how structural properties vary with molecular weight. We examined relationships among molar mass, radius of gyration, second virial coefficient, and critical overlap concentration to characterise different conformational states. Our results showed that as molar mass decreased, the chain diameter and persistence length also dropped, while the overlap concentration increased. This indicates a reduced hydrodynamic volume and increased chain flexibility. Positive second virial coefficient values indicate that polymer–solvent interactions remained favourable after photodegradation. The scaling exponents suggest that degraded heparin behaves as a semi-flexible polyelectrolyte and adopts an extended-coil shape in water with electrolytes. Further analysis showed that the characteristic ratio and chain stiffness decreased as chains were broken by irradiation. Overall, aerobic UVC irradiation provides a reliable way to modify the physical structure of these molecules while maintaining solution stability. These findings show a clear link between reduced molecular weight and changes in shape, which is useful for developing better low-molecular-weight heparins for several applications, including pharmaceutical and medical use. Full article

Coral mucus serves as a crucial defensive barrier for corals, where the mucus microbes play a vital role in the coral’s resistance to external stresses. However, detailed knowledge of the effect of UV radiation on coral mucus microbiome is limited, particularly regarding the UV resistance mechanisms of coral mucus microbes. This study investigates changes in the mucus microbial community and possible UV-resistant mechanisms of the mucus microbiota of Porites sp. and Favites sp. under UV stress using high-throughput sequencing, UV-resistant microbial isolation, and RT-qPCR analysis. Compared to the control, UV stress alters microbial community structure by reducing microbial diversity, e.g., the relative abundance of Aquibacter, Agaribacter, and Oleibacter in coral Porites sp., and the Roseobacter clade CHAB_I_5 lineage, Roseivirga, and Nautella in coral Favites sp. increase under UV stress. Meanwhile, it is indicated that the Favites sp. mucus microbiome is much more sensitive than the Porites sp. mucus microbiome. A total of 428 microbial strains belonging to 5 phyla, 7 classes, 15 orders, 23 families, and 47 genera were isolated from these two coral mucus species, with Ruegeria and Rossellomorea as the most abundant cultured taxa. Pseudoalteromonas galatheae strain P12 and Limimaricola pyoseonensis strains P2 and P9 have been proven to exhibit higher UV resistance by enhanced expression of tyr, sod, gogat, and uvrC genes, indicating that the UV resistance of coral mucus bacteria involves complex molecular processes, including upregulation of antioxidant enzyme expression and enhancement of melanin and glutamic acid biosynthesis. These findings enhance our understanding of coral mucus microbial ecological functions, particularly highlighting the coral mucus microbial UV resistance strategy. Full article

Mulch films play a vital role in modern agriculture by enhancing soil hydrothermal conditions, suppressing weed growth, and improving crop performance. Across 13 major crops, mulching increased yields by an average of 26%, with particularly strong responses in soybean (44%), millet (42%), wheat (29%), and maize (25%), and improved water-use efficiency by up to 33%. However, conventional polyethylene (PE) mulch films accumulate persistently in soils, reaching 7183–10,586 microplastic particles/kg in topsoil after long-term use and contributing up to 56% of total microplastics across the 0–100 cm soil profile. These residues impair enzymatic activity, disrupt nutrient cycling, and alter microbial community structure, making biodegradable alternatives essential for mitigating these issues. Lignin-based biodegradable mulch films (BDMs) have gained increasing attention owing to lignin’s intrinsic UV-shielding capacity, mechanical reinforcement, hydrophobicity, and biodegradability. Lignin-containing films may block UV radiation below 300 nm, reduce visible-light transmittance by ~80%, exhibit thermal stability up to 150 °C, and demonstrate low water vapour permeability (3.41 × 10⁻⁸ g/m·h·Pa) depending on formulation and lignin loading. Incorporation of lignin may enhance biodegradability, increasing soil-burial degradation by 25.47% relative to pure PVA, with composite systems achieving ~55% degradation within 50 days. This review provides a comprehensive assessment of lignin structure, sources, chemistry, extraction methods. It examines lignin as a renewable and value-added feedstock for mulch applications, and critically evaluates the optical, mechanical, thermal, hydrophobic, and biodegradation properties of lignin-based BDMs. The review also discusses their agronomic applications, including weed suppression, soil moisture retention, nutrient management, and soil microclimate regulation, while analysing the economic considerations affecting large-scale implementation and commercial feasibility. Finally, it outlines key research priorities to enable scalable, field-reliable, and environmentally sustainable mulch film technologies. Full article

Chronic inhalation exposure to nanoplastics, specifically polyethylene terephthalate (PET) nanoplastics (PET-NPLs) is an emerging health concern, yet the long-term consequences for genomic stability and DNA damage response (DDR) capacity in bronchial epithelial cells remain poorly characterized. For this study, human bronchial epithelial BEAS-2B cells were continuously exposed to PET-NPLs for over 20 weeks, after which elevated basal DNA genotoxic damage was observed, as assessed by the alkaline comet assay. In addition, a broad transcriptional suppression of the DDR, with 27 of 84 profiled genes involved in DDR showing reduced expression relative to passage-matched control was observed. The suppressed genes span ATM/ATR checkpoint signaling, homologous recombination (HR), base excision repair (BER), nucleotide excision repair (NER), and apoptotic pathways. To determine whether chronic PET-NPL exposure altered susceptibility to acute genotoxic challenge in a damage-type-specific manner, cells were treated with methyl methanesulfonate (MMS), ultraviolet-C (UV-C) radiation, or bleomycin. While MMS and UV-C induced comparable levels of DNA damage in control and PET-exposed cells, bleomycin produced significantly greater damage in PET-exposed cells, indicating selective sensitization to doble-strand breaks (DSB)-type and oxidative genotoxic insults. Transcriptional profiling during bleomycin challenge identified 18 DDR genes with relatively higher expression in PET-exposed cells compared to passage-matched controls, encompassing HR, BER, ATM/ATR signaling, the Fanconi anemia pathway, and apoptosis. Furthermore, PET-exposed cells retained significantly higher residual DNA damage after 3 h of bleomycin challenge, indicating a persistent early repair deficit. Together, these findings suggest that chronic PET-NPL exposure specifically compromises the bronchial epithelial DDR, with potential implications for long-term genomic stability in respiratory epithelia subjected to nanoplastic inhalation. Full article

Bacteriophages infecting phytopathogenic bacteria represent promising alternatives for plant disease control; however, some groups, such as filamentous bacteriophages, remain comparatively underexplored. In this study, we present a comprehensive characterization of XaF13, a filamentous bacteriophage that infects Xanthomonas vesicatoria, the causal agent of bacterial spot disease in pepper. Morphological analysis revealed a flexible filamentous virion architecture consistent with members of the family Inoviridae. To refine its genomic features, the XaF13 genome was resequenced through a hybrid approach combining newly generated Oxford Nanopore long reads with previously available Illumina data, resulting in a revised genome of 6965 bp. Comparative genomic analysis and intergenomic similarity assessment revealed low nucleotide identity with related inoviruses, supporting the recognition of XaF13 as a putative novel species based on VIRIDIC species-level thresholds. Phylogenetic reconstruction based on the Zot-like protein placed XaF13 within a broader inovirus lineage and showed that it forms a distinct evolutionary branch. In addition, physicochemical assays revealed that XaF13 remains stable across a broad pH range and tolerates brief exposure to elevated temperatures, whereas chloroform treatment and UV-C radiation reduced viral infectivity over time. Overall, these findings highlight the genomic distinctiveness and in vitro physicochemical stability of XaF13, contribute to a better understanding of filamentous bacteriophage diversity and provide a basis for future studies on its ecological role and possible interactions with phytopathogenic bacteria. Full article

During food intake, small amounts of antioxidants are absorbed and distributed to the extracellular matrix, from which they are made available to all types of cells. They protect against various free radicals generated in the extracellular and intracellular environments. They also protect against ionising radiation or UV directly. Some of the most abundant antioxidants in food are the proanthocyanidins, a form of condensed tannin found in tea, cocoa, and grape seeds. They also bestow various other health benefits as apoptosis inducers. The present study examines the vertical and adiabatic ionisation potentials and electron affinities of flavan, (−)-epicatechin, procyanidin B2, procyanidin C1, and cinnamtannin A2, and discusses the influence of non-equilibrated solvent–solute interactions on their electronic properties. The analysis employs the M06-2x/aug-cc-pVTZ//M06-2x/6-31++G** level of theory in the aqueous phase. Procyanidin C1 was found to have the lowest ionisation potential (6.08 eV) and the highest adiabatic electron affinity (1.15 eV); also, all (−)-epicatechin derivatives demonstrated a lower IP than guanine (6.42 eV), suggesting a potential genome-protective effect. These findings were confirmed by the global reactivity descriptor, the Fukui reactivity index, and the spin density distribution. The theoretical results presented here support the experimental results which predict that nutrients can help maintain a delicate redox balance which is crucial for the extra- and intracellular matrix. Full article

This study aimed to assess the risks associated with ultraviolet radiation (UVR) exposure among military outdoor workers at Lohatla Military Base, South Africa, and to inform targeted risk reduction strategies. A quantitative, cross-sectional design was employed, using a questionnaire survey with 161 participants (81% completion rate; 58.39% male; the largest age group was 19–25 years) and five days of objective environmental monitoring. Environmental data confirmed the presence of elevated solar ultraviolet radiation conditions, with peak irradiance levels recorded between 12:00 PM and 1:00 PM, while temperature highs frequently exceeded 35 °C (peaking at 39 °C). Statistical analysis using Spearman’s rank-order correlation revealed strong positive associations among sun protection behaviours, including wearing protective clothing, hat use, sunscreen use, and avoidance of peak sun exposure hours (ρ values up to 0.764, p < 0.001), indicating the clustered and interdependent nature of effective sun safety practices. Furthermore, engagement in protective behaviours was significantly associated with improved health outcomes, including a lower incidence of sunburn (ρ = 0.407, p < 0.001) and reduced hyperpigmentation (ρ = 0.438, p < 0.001). These findings indicate that combined protective strategies are associated with reduced self-reported dermatological outcomes. Despite the benefits of individual behaviours, military personnel remain exposed to high levels of environmental ultraviolet radiation, underscoring the need for institutional, evidence-based policy interventions to mitigate occupational exposure risks. The study concludes that military organisations should implement mandatory administrative controls (e.g., schedule adjustments), standardise high-ultraviolet-protection-factor protective gear, and enhance targeted health literacy training to mitigate long-term UV-related health risks and improve the operational effectiveness of their workers. Full article

Near-infrared radiation contributes to photoaging through oxidative stress and matrix metalloproteinase activation. Botanical extracts with antioxidant properties may offer additional protection beyond conventional UV filters. To evaluate the effect of hydrogel formulations containing Rosmarinus officinalis and Crataegus monogyna extracts on the directional reflectance of human skin across various spectral ranges. Directional reflectance was measured on the forearm skin of healthy female volunteers before and after application of a base hydrogel and hydrogels containing plant extracts. Hyperspectral imaging was used across spectral ranges of 335–2500 nm. To assess the application properties, rheological and textural evaluation of extract-based hydrogels was performed. The obtained results are satisfactory and indicate the expected application effectiveness of hydrogels with C. monogyna and R. officinalis extracts. Significant reductions in skin reflectance were observed in the IR spectrum after application of both botanical formulations. Median reflectance decreased by 3.5% with rosemary and 2.3% with hawthorn in the 1000–1700 nm range, and by 17.8% and 20.3% respectively in the 1700–2500 nm range. No statistically significant changes were observed in the UV or visible light ranges. Hydrogels enriched with R. officinalis and C. monogyna extracts reduced infrared reflectance of the skin, suggesting potential as adjunctive agents in photoprotection. These findings support further investigation into extract-based formulations for IR-related skin damage prevention. 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

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

Ageing radically alters the physicochemical properties of microplastics, significantly increasing their affinity for environmental pollutants. However, the slow nature of natural degradation necessitates the development of efficient laboratory protocols. This study establishes an accelerated ageing methodology that reflects natural dynamics by comparing Polyethene terephthalate microplastics (PET MPs) exposed to sunlight (3 months) with those exposed to laboratory UV-C radiation (varying lamp numbers and 24–336 h). scanning electron microscopy (SEM) imaging confirmed progressive surface degradation, including increased roughness, micro-cavities, and erosion. Photo-oxidation was evidenced by an increase in the carbonyl index (CI) from 7.43 ± 0.30 to 8.97 ± 0.35 (UV-aged) and 11.45 ± 0.45 (sun-aged). Furthermore, crystallinity significantly decreased from 59.5% to 54.4% and 16.6%, respectively, while the point of zero charge (pH_PZC) shifted from near neutral (6.5–7.0) to below 2.0. Notably, high-intensity, short-term UV-C exposure accelerated surface functionalization, enhancing cadmium adsorption capacity (q_e = 1.9 mg/g). The laboratory protocol provides rapid reactivation on the surface, serving as a proxy for prolonged sunlight exposure. Consequently, these findings offer a framework for assessing heavy metal uptake and the broader environmental implications of microplastics in aquatic environments. This understanding supports pollutant evaluation and sustainable water management for aquatic ecosystem protection. 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

(1) Background: Currently, there is a problem of prompt determination of fat and protein content in the milk–air mixture of milking machines. (2) Methods: A design of a sensor prototype is proposed, combining measurements of light scattering (scatterometry) and fluorescence (fluorometry) to determine the component composition of the milk–air mixture formed during milking. (3) Results: An optical and electronic circuit of a flow sensor has been developed, using four sources of optical radiation: blue, green and red semiconductor lasers (light scattering in milk) and a UV LED (milk fluorescence), as well as an axial photodiode array for recording the light scattering indicatrix and the fluorescence intensity of the milk–air mixture. The use of three laser sources in the scatterometric circuit allows for the determination of the fat content in milk with an error of 0.05%, which is better than all currently known analogs. The developed sensor enables the detection of counterfeit milk containing palm oil instead of milk fat. It operates reliably in a temperature range of 5–35 °C and at milk flow rates of up to 100 mL/sec. (4) Conclusions: The sensor is capable of transmitting real-time data on the fat and protein content of milk to an RS-232 serial port, enabling integration into milking robots and automated milking systems. Full article