Search Results (240)

Blackcurrant is a notable superfruit in Europe, and its vitamin C content surpasses the well-known blueberry superfruit. However, due to its short shelf life during storage, consumption is mainly accounted by frozen berries, extracts, and concentrates. This study applied an intensity of 1.2 W/m² UVC with different durations, including control (non-treated), UVC irradiation for 0.5 h (0.5 h treatment), UVC irradiation for 1 h (1 h treatment), and UVC pretreatment for 2 h (2 h treatment) to blackcurrant berries before storage. Fundamental physical (firmness and weight loss) and physicochemical characteristics (SSC, pH, and acids), microbial population changes, total phenolic content, antioxidant capacity, and specific phenolic compound changes were evaluated every five days over a twenty-day storage period. The results indicated that the longer the UVC pretreatment, the lower the water weight losses during storage. Meanwhile, the UVC pretreatment significantly affected the blackcurrant soluble solid content, resulting in higher soluble solid contents detected in the blackcurrants with the higher doses of UVC. For the mold population control, UVC effects were highly correlated with the pretreatment duration. However, UVC did not have a significant influence on the berry pH and acid contents, but the storage length slightly increased the pH and decreased the acids. At the same time, UVC pretreatment did not affect the berry firmness, polyphenols, ascorbic acid content, or antioxidant capacities, which were primarily influenced by the storage duration. The monophenolic compounds detected before and after storage indicated that more than one hour of UVC radiation influenced most of the phenolic contents largely before storage. The UVC pretreatment has also influenced some phenolic compounds. After storage, half an hour of UVC pretreatment increased cyanidin levels, and two hours of UVC pretreatment increased catechin and epicatechin levels. However, most of the compounds remained at similar amounts during storage in each treatment. Further research is needed to improve the UVC radiation time length or intensity or explore other technology combinations to optimize UVC pretreatments for blackcurrant storage. Full article

Microbial contamination of food can lead to faster spoilage and infections. Therefore, disinfection processes are required that have a low detrimental effect on the nutritional content. Concerning radiation disinfection, two spectral ranges have recently become important. The Far-UVC spectral range, with a wavelength below 230 nm and visible violet light. In this study, leaf spinach was used to investigate the extent to which these radiations inactivate Escherichia coli, but also to determine if the vitamin C or chlorophyll content was reduced. Frozen spinach leaves (Spinacia oleracea) were contaminated with E. coli × pGLO and irradiated with either a 222 nm krypton chloride lamp or 405 nm LEDs. The achieved bacterial reduction was determined by plating the irradiated samples on agar plates and subsequent colony counting. The vitamin C concentration was determined by means of redox titration, and the concentrations of chlorophyll a and chlorophyll b were determined using spectrometry. Both irradiations exhibited a strong antimicrobial impact on E. coli. The average log reduction doses were about 19 mJ/cm² (222 nm) and 87 J/cm² (405 nm), respectively. The vitamin C concentration decreased by 30% (222 nm) or 20% (405 nm), and the chlorophyll concentrations decreased by about 25%. Both irradiation approaches are able to substantially reduce microorganisms on spinach leaves by two orders of magnitude, but this is associated with a reduction in the nutrient content. Full article

Prolonged exposure to ultraviolet (UV) radiations represents a significant risk factor and may lead to various skin disorders, premature aging, and an increased susceptibility to skin cancers. Recently, probiotics have emerged as promising candidates for fortifying the skin’s natural defences through their diverse mechanisms. The aim of the present work was exploring the potential of five heat-treated probiotics (Skinbac^TM, Probiotical Research S.r.l., Novara, Italy), as protective agents against UVA and UVB damages on human keratinocyte line (HaCaT) and human skin 3D model (Phenion^® Full-Thickness Skin Model, Henkel AG & Co. KGaA, Dusseldorf, Germany). The protective role toward artificially induced oxidative stress was evaluated by determining the residual viability after UV exposure and analyzing gene expression of markers involved in apoptosis (Tumor protein 53), inflammation/immunosuppression (Interleukin 6), oxidative stress (oxidative stress response enzyme heme oxygenase 1), investigated using quantitative real-time PCR. Additionally, we examined the protective effects of these strains, testing them on Normal Human Epidermal Keratinocytes (NHEK) irradiated with UVC, specifically, evaluating the expression of tight junction proteins, including claudin 1, claudin 4, and occludin, by ELISA. The tested heat-treated probiotics effectively protected from UVA, UVB, and UVC damage on all end points analyzed, revealing their capacity to enhance barrier protection in cases of damage and their potential for innovative skincare strategies centered around probiotic-based formulations for enhanced protection against UV-induced skin damage. Full article

Leachates generated from the degradation of green waste and biosolids from urban wastewater treatment plants (WWTPs) pose significant environmental concerns due to high concentrations of organic pollutants and heavy metals. This study proposes a hybrid treatment strategy combining electrocoagulation (EC) and UVC-activated TiO₂ photocatalysis to remediate leachates produced in laboratory-scale biocells. Initial characterization revealed critical pollutant levels: COD (1373 mg/L), BOD₅ (378 mg/L), total phosphorus (90 mg/L), ammoniacal nitrogen (201 mg/L), and metals such as Ni, Pb, and Mn levels all exceeding those set out in the Ecuadorian discharge regulations. Optimized EC achieved removal efficiencies of 62.6% for COD, 44.4% for BOD₅, 89.8% for phosphorus, and 86.2% for color. However, residual contamination necessitated a subsequent photocatalytic step. Suspended TiO₂ under UVC irradiation removed up to 81.8% of the remaining COD, 88.7% of the ammoniacal nitrogen, and 94.4% of the phosphorus. Levels of heavy metals such as Zn, Fe, Pb, Mn, and Cu were reduced by over 80%, while Cr⁶⁺ was nearly eliminated. SEM–EDS analysis confirmed successful TiO₂ immobilization on sand substrates, revealing a rough, porous morphology conducive to catalyst adhesion; however, heterogeneous titanium distribution suggests the need for improved coating uniformity. These findings confirm the potential of the EC–TiO₂/UVC hybrid system as an effective and scalable approach for treating complex biocell leachates with reduced chemical consumption. Full article

Pharmaceutical residues are emerging contaminants of growing concern due to their persistence and poor removal efficiency in conventional wastewater treatment plants. This study evaluates UVC photolysis with type C ultraviolet radiation (UVC) and UVC/TiO₂ photocatalysis of a mixture of four pharmaceuticals—atenolol (ATL), acetaminophen (ACM), clofibric acid (CLA), and antipyrine (ANT)—commonly found in treated urban wastewater. A comprehensive kinetic model was developed to describe their degradation, taking into account the generation of reactive oxygen species (ROS): hydroxyl (HO^●), superoxide ion (O₂^●−) radicals, and singlet oxygen (¹O₂), along with their reactions with both the pharmaceuticals and dissolved organic matter. Direct quantum yields were determined as 8.05 × 10⁻³ mol·Einstein⁻¹ for ATL, 1.93 × 10⁻³ for ACM, 3.12 × 10⁻¹ for CLA, and 5.12 × 10⁻² for ANT. In addition, rate constants of the reactions between singlet oxygen and pharmaceuticals were 9.93, 1.3 × 10⁶, 1.18 × 10², and 1.14 × 10⁴ M⁻¹s⁻¹ for ATL, ACM, CLA, and ANT, respectively. Scavenger experiments confirmed the key role of the ROS involved. The model reproduces the inhibitory effect of natural organic matter in secondary effluent and, in most cases, treated, accurately predicts the concentration profiles of the pharmaceuticals. Under photocatalytic conditions (0.10 g·L⁻¹ TiO₂), all compounds were completely degraded in less than 15 min. This validated model provides a useful tool for understanding the degradation mechanisms of pharmaceutical mixtures and for supporting the design of effective water strategies based on photochemical processes. Full article

This paper presents the optimization of storage conditions for textile dosimeters for ultraviolet radiation measurements, which are based on cotton-woven fabric and nitroblue tetrazolium chloride (NBT) as a radiation-sensitive compound. The results of changes in light reflectance and color coordinates depending on the storage time of the samples over six months from their manufacturing under various storage conditions are presented. The results obtained for cotton—NBT dosimeters, unirradiated and irradiated with a UVC dose of 100 mJ/cm², stored under the following conditions were compared: (i) at room temperature (23–25 °C, humidity 40–60%), without access to light; (ii) in a fridge (3–5 °C, humidity 70–90%), without access to light; (iii) in a freezer (−17 to −20 °C, humidity 80–90%), without access to light; and (iv) at room temperature (23–25 °C, humidity 40–60%), with access to light. Additionally, it was presented that the cotton–NBT dosimeters were suitable for 2D measurement of UV radiation doses after a period of eight months. The obtained results complement previous studies on cotton–NBT textile dosimeters and are crucial for determining the conditions of use and the expiry date of such systems. Full article

Clostridioides difficile (CD) is a Gram-positive, spore-forming anaerobic bacterium, usually transmitted through the fecal–oral route, that can result from direct person-to-person contact, exposure to contaminated environmental surfaces, or contact with the hands of colonized healthcare personnel. An increased number of infections, especially healthcare-associated, with this etiology has been observed in most countries. As a spore-forming organism, CD is resistant to alcohol formulations and is a challenge for chemical disinfection. The solution could be the supplementation of traditional disinfection with non-touch techniques, such as UV-C radiation. The adoption of UV-C as a supplementary disinfection method in hospitals has significantly increased since the COVID-19 pandemic. However, there are no current guidelines concerning the use of UV-C disinfection in hospitals. The aim of this study was to evaluate the effectiveness of UV-C irradiation in inactivating Clostridioides difficile from different types of surfaces in hospital settings. The study was based on laboratory tests evaluating the efficacy in eliminating three different C. difficile strains on carriers made of plastic, metal and glass after 10 min exposure to UV-C (wavelength, 253.7 nm). We observed a wide range of reductions in the C. difficile suspensions depending on the density of the carrier contamination, type of carrier, strains and the location of the carrier. The percentage reductions ranged from 0 to 100%, but the best results were observed for glass, with lower initial suspension density and carrier placement on a door frame. Statistically significant differences were only seen in different suspension densities. Our experiment was a continuation of the tests done for non-sporing bacteria and C. auris, and there were some interesting differences in C. difficile reflecting its biology, especially its sensitivity to an aerobic atmosphere during the sample drying. Although the elimination of C. difficile by UV-C radiation was confirmed in our experiment, it was lower than in the case of non-spore-forming bacteria. Thus, this method may be used in healthcare settings (hospitals) for improving environmental safety and preventing C. difficile spreading. Full article

This study investigates the AI-assisted analyses of radiation disinfection effects on the mechanical properties of recycled date kernel powder–epoxy composites for medical applications, utilizing Euclidean distances and the k-nearest neighbor (KNN) algorithm. Tensile and compression tests were conducted on twenty specimens following ASTM standards, with the data analyzed using a t-test to evaluate the impact of the UVC disinfection process on the material’s mechanical properties. The application of AI through the KNN algorithm successfully identified the three most representative curves out of five for both tensile and compression tests. This targeted curve selection minimized variability and focused on the most relevant data, enhancing the reliability of the analysis. Following the application of UVC and AI, tensile tests showed a 20–30% increase in ultimate stress. Similarly, compression tests revealed a 25% increase in transition stress, an 18–22% improvement in ultimate stress, and approximately a 12% rise in fracture stress. This research underscores the potential of combining AI, sustainable materials, and UVC technology to develop advanced composites for medical applications. The proposed methodology offers a robust framework for evaluating material performance while promoting the creation of eco-friendly, high-performance materials that meet the stringent standards of medical use. Full article

Saponins from leaves of Quillaja lancifolia, a native species from southern Brazil, show potent immunoadjuvant activity in experimental vaccine formulations. The accumulation of the immunoadjuvant saponin fraction QB-90 is induced in cultured leaf disks and seedlings by several stresses and stress signaling molecules, such as osmotic agents, salicylic acid, jasmonic acid, mechanical damage, ultrasound, UV-C radiation, and high light irradiance. These observations suggest a role in plant defense. To further examine this possibility, an investigation of the potential inhibitory role of Q. lancifolia saponins on plant and human pathogenic fungi and two herbivore models was carried out. The screening tests showed that saponin-rich fractions, particularly QB-90, were able to significantly inhibit the growth of Bipolaris micropus, Curvularia inaequalis, Fusarium incarnatum, and Cryptococcus gattii R265. The same metabolites acted as deterrents against the generalist mollusk and insect herbivores Helix aspersa and Spodoptera frugiperda, respectively. Significant reductions in consumption of leaf area and larvae body weight were recorded. Taken together, these data indicate a role for Q. lancifolia saponins in plant defense against diverse herbivores and fungi, having potential as a natural pest control agent and/or as a molecular platform for the development of new environmentally friendly biocide molecules. Full article

This study evaluates the effects of ultraviolet (UV) radiation (UVA, UVB, and UVC) on the postharvest quality and nutritional stability of fresh-cut spinach during cold storage. Spinach samples were exposed to UV treatments for 0, 5, or 10 min and stored at 4 ± 1 °C with 85 ± 5% relative humidity for up to 10 days. Weight loss, dry matter content, total soluble solids, electrical conductivity, pH, respiration rate, color parameters, ash content, and mineral composition were assessed. The results showed that UVB-treated spinach had the lowest weight loss (0.52%), compared to UVC-treated (0.75%) and control (0.82%) samples. The dry matter content was highest in UVB-treated samples (9.56%) and lowest in UVC-treated samples (8.62%). UVC exposure increased electrical conductivity (112 µS cm⁻¹), indicating greater ion leakage. UVA and UVB treatments preserved the chlorophyll content (SPAD values of 34.5 and 37.0, respectively) and reduced the respiration rates. These physiological responses are indicative of delayed senescence and improved storage potential. UVB-treated samples retained higher potassium (4040 mg 100 g⁻¹), calcium (1445 mg 100 g⁻¹), and phosphorus (375 mg 100 g⁻¹), while UVC-treated samples showed greater mineral loss. Hierarchical clustering analysis revealed distinct metabolic responses among UV treatments. This study provides a novel comparative assessment of UVA, UVB, and UVC effects on fresh-cut spinach, demonstrating UVB as the most effective non-chemical method for enhancing shelf life while preserving nutritional quality. Full article

This paper addresses the upconversion of blue light to ultraviolet-C (UVC) with Pr³⁺-activated materials for antibacterial applications of UVC. It discusses the processes through which UV radiation provides biocidal effects on microorganisms, along with the most popular UVC sources employed in these processes. We describe the electronic and optical properties of the Pr³⁺ ion, emphasizing the conditions the host material must meet to obtain broad and intense emission in the UVC from parity-allowed transitions from the 4f5d levels and provide a list of materials that fulfill these conditions. This paper also delineates lanthanide-based upconversion, focusing on Pr³⁺ blue to UVC upconversion via the ³P₀ and ¹D₂ intermediate states, and suggests routes for improving the quantum efficiency of the process. We review literature related to the use of upconversion materials in antimicrobial photodynamic treatments and for the blue to UVC upconversion germicidal effects. Further, we propose the spectral overlap between the UVC emission of Pr³⁺ materials and the germicidal effectiveness curve as a criterion for assessing the potential of these materials in antimicrobial applications. Finally, this paper briefly assesses the toxicity of materials commonly used in the preparation of upconversion materials. Full article

Field horsetail (Equisetum arvense L.) is widely utilized in traditional medicine and is a rich source of bioactive compounds such as flavonoids, phenolic acids, and silica. This study investigates the protective effect of the polyphenolic extract from field horsetail (HLE) on erythrocytes and their cell membranes. The content of polyphenolic compounds in the extract was determined using the HPLC-DAD and Folin–Ciocalteu methods. The extract’s hemolytic activity, toxicity, antioxidant activity, and its impact on the physical properties of erythrocytes and lipid membrane were investigated. The antioxidant properties were evaluated using erythrocytes and isolated erythrocyte membranes oxidized by UVC radiation and AAPH. The impact of the extract on the ordering and fluidity of erythrocyte and model lipid membranes was studied. Furthermore, the transmembrane potential, shape of erythrocytes and the dipole potential of the lipid membranes under the influence of HLE were evaluated. The results indicated that HLE extract exhibited no toxicity to erythrocytes and HMEC-1 cells. HLE components effectively protect erythrocytes and their membranes against oxidation. They interact with the outer, polar surface of the erythrocyte membrane and reduce both erythrocyte membrane potential and lipid membrane dipole potential. The HLE polyphenols decrease the concentration of free radicals at the surface of the membrane, where they are located, and serve as a protective barrier, preventing penetration into the membrane. Full article

The customization and handling of implant abutments in prosthetic laboratories can lead to microbial contamination, requiring disinfection before clinical use. This study evaluated cross-contamination in abutments from three prosthetic laboratories, identifying microorganisms and assessing the disinfection efficacy of 2% chlorhexidine digluconate (2% CL) and ultraviolet C (UV-C) radiation. Sixty abutments were analyzed, with contamination detected in 83%, predominantly Enterococcus faecalis (34.2%) and Staphylococcus epidermidis (17.8%). Post-disinfection, CFU reduction was 92% (UV-C) and 93% (CL), confirmed by the Wilcoxon test (Z = −4.373; p < 0.001). A comparative analysis using the Kruskal–Wallis test showed no significant difference between the two methods (p > 0.05). These findings confirm that both UV-C and CL effectively reduce microbial load, providing reliable disinfection protocols for clinical practice. Full article

Controlled-environment crop production often weakens plants’ defense mechanisms, reducing the accumulation of protective phytochemicals essential to human health. Our previous studies demonstrated that short-term supplementation of low-dose ultraviolet (UV) light to the red–green–blue (RGB) spectrum effectively boosts secondary metabolite (SM) synthesis and antioxidant capacity in lettuce. This study explored whether similar effects occur in basil cultivars by supplementing the RGB spectrum with ultraviolet B (UV-B, 311 nm) or ultraviolet C (UV-C, 254 nm) light shortly before harvest. Molecular analyses focused on UV-induced polyphenol synthesis, particularly chalcone synthase (CHS) level, and UV light perception via the UVR8 receptor. The impact of high-energy UV radiation on the photosynthetic apparatus (PA) was also monitored. The results showed that UV-B supplementation did not harm the PA, while UV-C significantly impaired photosynthesis and restricted plant growth and biomass accumulation. In green-leaf (Sweet Large, SL) basil, UV-B enhanced total antioxidant capacity (TAC), increasing polyphenolic secondary metabolites and ascorbic acid (AsA) levels. UV-C also stimulated phenolic compound accumulation in SL basil but had no positive effects in the purple-leaf (Dark Opal, DO) cultivar. Interestingly, while the UV-B treatment promoted UVR8 monomerization in both cultivars, the enhanced CHS level and concomitant SM synthesis were noted only for SL basil. In addition, UV-C also induced CHS activity and SM synthesis in SL basil but clearly in a UVR8-independeted manner. These findings underscore the potential of UV light supplementation for enhancing plant functional properties, highlighting species- and cultivar-specific effects without compromising photosynthetic performance. Full article

Background and Objectives: The cornea protects the eye from external influences and contributes to its refractive power. Corneas belong to the most frequently transplanted tissues, providing a last resort for preserving the patient’s vision. There is a high demand for donor corneas worldwide, but almost 4% of these transplants are not eligible due to microbial contamination. The objective of this study is to ascertain the suitability of 222 nm Far-UVC irradiation for the decontamination of corneas without damaging corneal endothelial cells. Materials and Methods: To assess the destructive effect of irradiation and, thus, identify the applicable dose needed to decontaminate the cornea without interfering with its integrity, 141 porcine corneas were irradiated with 0, 60 or 150 mJ/cm² at 222 nm. In the second step, a series of 13 human corneas were subjected to half-sided irradiation using 15 or 60 mJ/cm² at 222 nm. After five days of in vitro culturing, the endothelial cell density of the non-irradiated area of each human cornea was compared to the irradiated area. Results: Irradiation with up to 60 mJ/cm² had no detectably significant effect on the cell integrity of human corneas (p = 0.764), with only a minimal reduction in cell density of 3.7% observed. These findings were partially corroborated by tests on porcine corneas, wherein the variability between test groups was consistent, even at increased irradiation doses of up to 150 mJ/cm², and no notable effects on the irradiated porcine endothelium were monitored. The efficacy of the antimicrobial treatment was evident in the disinfection tests conducted on corneas. Conclusions: These initial irradiation experiments demonstrated that 222 nm Far-UVC radiation has the potential to decontaminate the cornea without compromising sensitive endothelial cell viability. Full article