Search Results (504)

Prolonged ultraviolet (UV) exposure accelerates aging and degradation, while conventional constant-intensity UV simulations do not reflect the variable nature of outdoor radiation. Aging duration and film thickness are both key factors affecting Rubber-Modified Asphalt (RMA), but how their combination influences RMA remains unclear. To address this limitation, this research employed accelerated aging experiments under variable-intensity UV radiation to investigate the performance and aging mechanism of RMA across different aging durations and asphalt film thicknesses. Rheological properties were analyzed through rheological tests, and the UV aging mechanisms of RMA were revealed using FTIR and SEM. The results revealed that crumb rubber improved RMA’s UV aging resistance, including high-temperature performance, fatigue life, and low-temperature cracking resistance. Aging effects were more influenced in RMA with thinner films under prolonged UV exposure. After nine cycles of ultraviolet aging, the rutting resistance, elastic recovery, fatigue life, and low-temperature cracking resistance of RMA with a 1 mm film thickness were 1.33, 1.11, 0.54, and 0.67 times, respectively, those of RMA with a 2 mm film thickness subjected to three UV aging cycles. RMA demonstrated comparable high-temperature performance and elastic recovery under UV aging conditions corresponding to a 1.5 mm film thickness aged for three cycles and a 2.0 mm film thickness aged for six cycles, as well as a 1.0 mm film thickness aged for six cycles and a 1.5 mm film thickness aged for nine cycles. FTIR showed that the increased activity of C=C and C-H under photo-oxidative aging caused a greater impact on the carbonyl groups than the sulfoxide groups. Under high-intensity UV radiation, RMA with thinner films exhibited greater rubber powder detachment, increased surface oxidation, and a substantial widening of cracks. The rubber powder absorbed UV radiation, enhancing the stability of RMA. The maximum crack width of the 1 mm NA was twice that of RMA. These provided insight into the microstructural pattern of cracking resistance degradation caused by aging. This research provides theoretical support for the optimization of the anti-aging performance of RMA. Full article

Skin damage and premature aging are predominantly driven by UV radiation through several mechanisms. The most common of these are by reactive oxygen species (ROS) generation, upregulation of matrix metalloproteinases (MMPs), and weakened antioxidant defenses. Moringa oleifera is a nutritionally valuable plant with diverse biological activities. This study optimized ethanol concentrations coupled with ultrasonic-assisted extraction to maximize the yield and efficacy of M. oleifera leaf extract (MOLE). We also elucidated the underlying mechanisms of MOLE in protecting against photooxidative damage and skin aging from UVB exposure in HaCaT keratinocytes. Extraction with 50% ethanol produced the highest total phenolic and flavonoid contents, aligning with the greatest antioxidant activity by ABTS and FRAP assays. MOLE showed no significant cytotoxicity up to 1000 µg/mL in the MTT assay. MOLE protected cells from detrimental UVB radiation by scavenging ROS; reducing cell damage and death; enhancing gene expression of superoxide dismutase (SOD-1), glutathione peroxidase (GPx), and catalase (CAT); and improving SOD activity. UVB exposure elevated MMP-1, MMP-3, and MMP-9 expression and decreased collagen type I (col-1) and elastin (ELN) expression, while these effects were ameliorated by MOLE. Our findings suggest that MOLE protected against UVB-induced photooxidative damage and premature aging in the HaCaT keratinocytes. Full article

Jasmine (Jasminum sambac (L.) Ait.) flowers, valued for their fragrance and essential oils, are extensively used in the flavor, cosmetics, and pharmaceutical industries. However, their useful life is short due to rapid color degradation and browning caused by photo-oxidative stress induced by environmental factors like light, temperature, and humidity. Therefore, the significant reduction in the visual appeal, quality, and economic value necessitates the measurement of temporal color degradation to evaluate the shelf life for jasmine flowers. A developed open-source ImageJ plugin program quantified the color degradation of jasmine petals and pedicles over 25 h. Petal area (>19 mm²) cutoff separated the pedicles. Color degradation kinetics models, including zeroth-order, first-order, exponential decay, Page, and Peleg, using several color indices, were developed, and their performances were evaluated. VEG, hue, chroma, COM, and CIVE color indices were found suitable for kinetics modeling. Peleg and Page models ($R^2\ge 0.99$) are suitable for petals and pedicles, respectively. Jasmine petals retained their color integrity for longer periods than pedicles. This study underscores the potential of computer vision analysis and kinetic modeling for evaluating flower quality after harvest. The color degradation dynamics were accurately characterized by the kinetic models, which provide actionable insights for optimizing storage and handling practices. Full article

Asphalt binder aging under natural exposure critically determines pavement durability, though current research inadequately captured performance evolution across diverse regional climates. This study investigated climate-driven degradation mechanisms through 12-month all-weather aging (AWA) tests in Gansu, Shandong, and Beijing via rheological (G-R parameter, stiffness modulus S-value) and chemical analyses (carbonyl index I_C=O, sulfoxide index I_S=O). The results demonstrated significant region-dependent aging disparities beyond laboratory simulation. In Gansu, extreme thermal fluctuations and UV radiation accelerated hardening via thermal stress cycles and photo-oxidation, yielding 52.4% higher G-R parameter than PAV. In Shandong, humid saline environments triggered sulfur oxidation-driven electrochemical corrosion, increasing I_S=O by 4.2% compared to PAV. In Beijing, synergistic UV–thermal oxidation elevated I_C=O and S-value by 8% and 40.7%, respectively versus PAV. Critically, I_C=O exhibited strong positive correlations with rheological degradation across regions (r > 0.90, p < 0.01). Based on I_C=O, the 12-month all-weather aging rate in Beijing exceeded Gansu and Shandong by 18.5% and 68%, revealing UV–thermal coupling as the most severe degradation pattern. Novelty lies in quantifying region-specific multi-factor coupling effects (UV–thermal, hygrothermal–salt, etc.) and demonstrating their superior severity over PAV (Beijing > Gansu > Shandong). Dominant environmental factors showed distinct regional variations: UV radiation and temperature difference dominated in Gansu (I_C=O, r = 0.76) and Beijing (0.74), while precipitation—I_C=O correlation prevailed in Shandong (0.76), yet multi-factor coupling ultimately governed aging. These findings provide theoretical foundations for region-tailored and climate-resilient asphalt pavement design. Full article

Conventional micropropagation of cannabis struggles with excessive callus hyperhydration, slow growth, low rooting efficiency, and high contamination risk, all of which greatly restrict its feasibility for large-scale propagation. In contrast, photoautotrophic micropropagation (PAM) has emerged as an efficient and cost-effective propagation strategy that can significantly enhance plantlet growth and improve seedling quality by optimizing the LED lighting environment. This study investigated the effects of four light intensities (50, 100, 150, and 200 µmol m⁻² s⁻¹) and three photoperiods (16, 20, and 24 h d⁻¹) on the growth and rooting of two medicinal cannabis cultivars (the short-day cultivar ‘Charlotte’ and the day-neutral cultivar ‘Auto Charlotte’). Cluster analysis revealed that plantlets grown under the photoperiod of 20 h d⁻¹ and light intensity of 100–150 µmol m⁻² s⁻¹ exhibited optimal growth performance in terms of plant height, root length, leaf number, leaf area, biomass, and root activity. Moreover, increasing the light intensity from 50 to 100–150 µmol m⁻² s⁻¹ significantly enhanced net CO₂ exchange rates by 41.5% and 204.9% for Charlotte and Auto Charlotte, respectively, along with corresponding increases in dry matter accumulation of 44.3% and 27.9%. However, the plantlets exhibited photooxidative damage under continuous lighting and light intensity of 200 µmol m⁻² s⁻¹, as evidenced by reduced photosynthetic pigment content and suppressed antioxidant enzyme activity. Therefore, PAM of medicinal cannabis is recommended under the LED lighting environment with light intensity of 100–150 µmol m⁻² s⁻¹ and photoperiod of 20 h d⁻¹ to achieve optimal growth and rooting. These findings provide essential technical support for the large-scale propagation of vigorous, disease-free female plantlets with well-developed root systems and high genetic uniformity, thereby meeting the stringent quality standards for planting materials in the commercial cultivation of cannabis for medical and pharmaceutical use. Full article

Laser patterning of sol–gel-derived TiO₂ coatings offers a promising route for fabricating TiO₂-based devices. Conventional approaches require high-power CO₂ lasers, whereas herein is demonstrated an alternative method using a low-cost, blue laser (λ = 445 nm, 1250 mW) to pattern TiO₂ layers derived from a visible-light-absorbing titanium salicylate sol. Grid-shaped TiO₂ patterns (~250 μm line, 500 μm pitch) were fabricated on indium tin oxide (ITO)-coated glass substrates via dip-coating, laser patterning, selective solvent removal, and annealing at 450 °C. Photocatalytic performance was enhanced through Ag photodeposition from a 5 mM Ag⁺ aqueous electrolyte under UV doses of 5, 10, and 20 J cm⁻². Structural and compositional analysis (XRD, SEM-EDS, AFM, UV–Vis, Raman) confirmed the formation of crystalline anatase TiO₂ and Ag incorporation proportional to the dose. Methylene blue (MB) photooxidation experiments revealed that Ag-functionalized samples showed up to 20% higher degradation efficiency and improved photocatalytic stability across eight consecutive MB oxidation cycles. Additional photoelectrochemical measurements confirmed the formation of a TiO₂/Ag Schottky junction, while surface-enhanced Raman scattering (SERS) signals observed on Ag/TiO₂ grids enabled the detection of MB adsorbates. Full article

This study examines the UVB-induced (Ultraviolet B radiation) degradation of carbon black-filled polyvinyl chloride (CB-PVC) composites. After 500 h of exposure, the material exhibited a 30.13% drop in dielectric strength, a 27.6% increase in surface roughness, and significant pit formation, indicating substantial physicochemical deterioration. Degradation followed a triphasic kinetic pattern: an initial induction phase, an autocatalytic acceleration, and a stabilization phase, driven by radical propagation and photo-oxidation. These findings highlight the complex role of UVB in the photodegradation of cable sheeting. Full article

Background/Objectives: D-lysergic acid diethylamide (D-LSD) is under investigation as a potential therapeutic strategy for alcohol use disorder (AUD). However, the extreme light sensitivity of D-LSD presents a significant challenge in developing suitable pharmaceutical forms, particularly for clinical trial settings. This study proposes a liquid-filled capsule formulation designed to provide accurate dosing while protecting D-LSD from photodegradation. Methods: To support formulation development and ensure its suitability as an investigational medicinal product, a multi-tiered analytical strategy was employed. This included liquid chromatography coupled with ion mobility spectrometry and mass spectrometry (LC-IM-MS), along with quantum chemical calculations (density functional theory (DFT) and time dependent-DFT (TD-DFT)), to ensure robust and orthogonal structural characterization of degradation products. Results: Photostress studies demonstrated that while D-LSD in solution rapidly degrades into photoisomers and photooxidative byproducts, the capsule formulation markedly mitigates these transformations under ICH-compliant conditions. Conclusions: These findings highlight the essential role of orthogonal stability profiling in guiding formulation development and demonstrate that this approach may offer a viable, photostable platform for future clinical investigation of D-LSD in the treatment of AUD. Full article

Camellia oil, rich in monounsaturated fatty acids, squalene, tocopherols, and polyphenols, is highly valued for its nutritional benefits. However, its high market value and regional variations have led to frequent adulteration, highlighting the need for rapid, non-destructive methods for authentication, geographical traceability, and quality assessment. This study employed portable Raman spectroscopy combined with Partial Least Squares Discriminant Analysis (PLS-DA) and Multivariate Curve Resolution–Alternating Least Squares (MCR-ALS) to differentiate camellia oil from other edible oils and evaluate its thermal and photo-oxidative stability. PLS-DA, based on VIP-selected spectral variables, effectively distinguished camellia oil, with Raman bands near 1250 cm⁻¹ and 1650 cm⁻¹ contributing significantly. A unique peak at 1525 cm⁻¹, observed in samples from Gongcheng, Guangxi, was associated with carotenoids and served as a potential marker for geographical traceability. MCR-ALS modeling revealed significant reductions in the 1650 cm⁻¹ and 1525 cm⁻¹ peaks when temperatures exceeded 150 °C, indicating degradation of unsaturated fatty acids and carotenoids. Under UV exposure, the 1525 cm⁻¹ peak declined sharply and nearly disappeared after 24 h, suggesting rapid carotenoid degradation via photooxidation. Extended UV treatment also affected the 1650 cm⁻¹ peak and led to oxidative product accumulation. Overall, this study demonstrates the feasibility of integrating Raman spectroscopy with chemometric analysis for efficient oil classification, traceability, and stability monitoring, offering a valuable tool for food quality control and market supervision. Full article

With the increase in biodiesel production experienced in the last decades, biomass-derived glycerol is obtained at a high rate, so glycerol availability in the market has scaled up while this polyol price has been reduced, with the exception of high-quality glycerol. In this context, novel and sustainable products based on glycerol are actively looked for. Octyl-methoxycinnamate (OMC) is a common cosmetic ingredient and sunscreen with potential activity as an endocrine disruptor that is considered an emergent contaminant in aquatic environments. As possible substituents, glycerol-based methoxycinnamates such as monoglycerides can be obtained via lipase-driven esterification. In this work, we develop an enzymatic process under solventless conditions to obtain p-methoxycinnamate monoglyceride under mild conditions using Novozym 435—an immobilized industrial preparation of the lipase B of Candida antarctica—observing the effect of key process variables such as temperature and enzyme, water and acid concentrations. Furthermore, the obtained product was assessed for its activity as UVB-filter and for its stability under irradiation conditions, showing a similar SPF activity and a much higher stability toward photooxidation than OMC. Full article

Photochemical degradation is a major removal pathway for pharmaceutical pollutants in water, and dissolved organic matter (DOM) in water is an important factor affecting this process. This study investigates the differential effects of seasonally-varied dissolved organic matter (DOM) from Songhua River and Liao River on the photodegradation of pharmaceutical pollutants, using levofloxacin (LFX), sulfamethoxazole (SMZ), and ibuprofen (IBP) as target compounds. The results demonstrated that summer and autumn DOM inhibited the photodegradation of LFX and SMZ through light screening and dynamic quenching effects, with inhibition rates of 35.1% and 55.5%, respectively, whereas winter DOM enhanced degradation through photo-oxidation mechanisms. DOM from Songhua River and Liao River significantly promoted the photodegradation of IBP. Quenching experiments showed differences in the contributions of photochemically reactive intermediates (PPRIs) to the photodegradation of different target pollutants, with hydroxyl radicals (•OH) dominating LFX photodegradation (48.79% contribution), excited triplet states of DOM (³DOM*) dominating SMZ photodegradation (85.20% contribution), and singlet oxygen (¹O₂) dominating IBP photodegradation (79.89% contribution). The photodegradation pathways were elucidated by measuring the photodegradation by-products of the target pollutants: LFX mainly underwent piperazine ring cleavage and oxidative decarboxylation, SMZ underwent isoxazole ring opening and deamination during photodegradation, and IBP underwent photodecarboxylation and oxidation reactions. Under the influence of the DOM from the Songhua River and Liao River, the generation of multiple photodegradation by-products led to an increasing trend in the acute toxicity of target pollutants to luminescent bacteria. This investigation elucidates the dual regulatory mechanisms of natural aquatic DOM on both photo-induced degradation pathways and toxicity evolution dynamics of pharmaceutical contaminants, which is of great significance for understanding the photochemical transformation behavior and risk assessment of pharmaceutical pollutants in aquatic environments. Full article

Food contact polymers require thermochromic pigments to provide temperature-sensitive visual cues for consumer safety and product integrity. However, their susceptibility to ultraviolet (UV) degradation limits long-term application. This study investigates the UV resistance of food-grade thermochromic polypropylene blends under simulated indoor and outdoor UV exposure for 500 and 1000 h. Visual properties, colorimetric (CIE L*a*b*) measurements, mechanical testing (tensile and impact), and mass variation analysis were performed to assess photostability and material integrity. Exposure to UV led to progressive discoloration (ΔE*_ab up to 34.07) and significant mechanical deterioration. Tensile strain at break decreased by 48.67%, and notched impact strength dropped by 44.15% after 1000 h of UV exposure. No measurable mass loss occurred, indicating degradation was confined to surface-level oxidation rather than bulk material erosion or leaching. These findings highlight the need for optimal pigment loading and UV stabilization to extend the shelf life of thermochromic food packaging materials in light-exposed storage and retail environments. The study offers a framework for improving the long-term reliability of smart packaging in the food industry. This work uniquely integrates optical, mechanical, and mass loss analyses to evaluate thermochromic packaging degradation under extended UVA exposure. Full article

Tea plants (Camellia sinensis) are among the world’s most significant economic tree species. Tissue culture serves as a crucial method in commercial breeding by facilitating the rapid propagation of valuable genotypes and the generation of disease-free clones. However, callus browning represents a prevalent challenge in tea plant tissue culture, and may adversely affect explant growth and development. Our research demonstrates that although anti-browning agents can effectively suppress browning, they induce distinct color changes in the callus. These color variations could significantly influence callus induction and subsequent growth patterns. In this study, callus tissues from C. sinensis var. Assamica cv. Mengku were employed as experimental materials and treated with three commonly used anti-browning agents: ascorbic acid (VC), activated carbon (AC), and polyvinylpyrrolidone (PVP). The results demonstrated that while these three reagents effectively inhibited browning, they also induced distinct color changes in the explants, which appeared red, green, and white, respectively. Furthermore, this study investigated the molecular mechanisms underlying callus color changes using transcriptomic and metabolomic approaches. Based on transcriptome analysis, it was revealed that photosynthesis and flavonoid biosynthesis pathways were significantly enriched. Metabolome analysis identified 14 phenolic acids, which exhibited significant variation in accumulation across calluses of different colors. The differential expression of genes involved in flavonoid biosynthesis pathways, coupled with the distinct accumulation patterns of metabolites, can effectively alleviate photooxidative damage and enhance the resistance of callus to browning. AC activates the photosynthesis of callus by regulating carbon source allocation and upregulating the expression of key genes in the psa, psb, and pet families within the photosynthetic system. This process promotes chlorophyll biosynthesis, thereby enabling the callus to grow green, while VC activates the expression of key genes such as CHS, F3H, C4H, CYP75B1, and ANR in the flavonoid pathway, which are involved in the regulation of pigment synthesis in red callus. This study elucidated the molecular mechanisms underlying the effects of anti-browning agents on color variations in C. sinensis callus, thereby providing a robust theoretical foundation for optimization, the establishment of tea plant tissue culture systems, and enhancing cultivar quality. Full article

One of the most urgent threats to public health worldwide is the ongoing rise of multidrug-resistant (MDR) bacterial strains. Among the most critical pathogens are MDR-Klebsiella pneumoniae strains. The lack of new antibiotics has led to an increased need for non-antibiotic antimicrobial therapies. Photodynamic therapy (PDT) has become increasingly significant in treating MDR bacteria. PDT uses photosensitizer compounds (PS) that generate reactive oxygen species (ROS) when activated by light. These ROS produce localized oxidative stress, damaging the bacterial envelope. A downside of PDT is the limited bioavailability of PSs in vivo, which can be enhanced by conjugating them with carriers like nanoparticles (NPs). Zinc nanoparticles possess antibacterial properties, decreasing the adherence and viability of microorganisms on surfaces. The additive or synergistic effect of the combined NP-PS could improve phototherapeutic action. Therefore, this study evaluated the effectiveness of the copper(I)-based PS CuC1 compound in combination with Zinc Oxide NP, ZnONP, to inhibit the growth of both MDR and sensitive K. pneumoniae strains. The reduction in bacterial viability after exposure to a PS/NP mixture activated by 61.2 J/cm² of blue light photodynamic treatment was assessed. The optimal PS/NP ratio was determined at 2 µg/mL of CuC1 combined with 64 µg/mL of ZnONP as the minimum effective concentration (MEC). The bacterial gene response aligned with a mechanism of photooxidative stress induced by the treatment, which damages the bacterial cell envelope. Additionally, we found that the PS/NP mixture is not harmful to mammalian cells, such as Hep-G2 and HEK-293. In conclusion, the CuC1/ZnONP combination could effectively aid in enhancing the antimicrobial treatment of infections caused by MDR bacteria. Full article

Although melanin is viewed as a natural sunscreen that protects pigmented cells against the adverse effects of solar radiation, recent studies have demonstrated that, under certain conditions, the pigment can actually contribute to light-induced oxidative damage of the cells. However, the main issue with such studies is finding natural pigments without photooxidative modifications. Recently, melanin obtained from melanocytes, generated from human induced pluripotent stem cells (hiPSC-Mel), was suggested as a promising source of the pigment without significant photooxidation. Although different studies have demonstrated the feasibility of the above-mentioned technique to obtain melanin-producing cells, no thorough analysis of the physicochemical properties of the pigment has been performed. To address this issue, we examined the key physicochemical parameters, including the aerobic photoreactivity of melanin isolated from hiPSC-Mel and compared them with those of melanin from other known sources of the pigment, such as bovine retinal pigment epithelium (bRPE) and phototype V (PT-V) hair. Electron paramagnetic resonance (EPR) spectroscopy, dynamic light scattering, UV–Vis absorption and HPLC analysis of melanin degradation products were used. The ability of the examined melanins to photogenerate reactive oxygen species was determined by employing EPR oximetry, EPR spin-trapping and time-resolved singlet oxygen phosphorescence. Although the results of such measurements demonstrated that melanin obtained from hiPSC-Mel exhibited the physicochemical properties typical for eumelanin, a contribution from pheomelanin with a substantial presence of benzothiazine subunits, was also evident. Importantly, the hiPSC-Mel pigment had significantly lower photoreactivity compared to bRPE melanin and PT-V hair melanin. Our findings indicate that hiPSC-Mel could be an excellent source of high-quality pigment for photoprotection studies. Full article