Search Results (404)

The objective of this study was to evaluate the solar photocatalytic degradation of the disperse textile dye 2-(4-amino-2-nitrophenyl)-1,3-benzothiazole using titanium dioxide nanoparticles (TiO₂ P25) under a mean solar irradiance of 492 ± 58 W/m², evaluating the effects of pH, photocatalyst concentration, and continuous aeration on process efficiency. The degradation of the dye was determined by monitoring its concentration by UV–Visible spectrophotometry, while the mineralization was evaluated by chemical oxygen demand (COD). Likewise, kinetic behavior was analyzed using pseudo-first-order and pseudo-second-order models. The results showed that the degradation efficiency increased with the concentration of TiO₂, reaching the highest yield with 400 ppm of TiO₂ and continuous aeration, which confirms that both variables are determining operating factors for maximizing photocatalytic efficiency. pH exerted a significant influence on the activity of the system, obtaining the highest degradation efficiencies and the greatest reductions in COD under slightly alkaline conditions (pH 8–9), a behavior attributed to the greater colloidal stability of TiO₂ and the modification of its surface properties with respect to its point of zero charge (pHpzc ≈ 6.2). The pseudo-second-order model generally provided an adequate empirical description of the experimental data; however, the best-fitting model varied depending on the experimental condition. The simultaneous decrease in the concentration of the dye and the COD confirmed that the treatment produced not only the decolorization of the solution, but also the progressive oxidation of the organic matter. Integrating kinetic analysis with the simultaneous assessment of decolorization and COD enabled clear experimental differentiation between adsorption and photocatalysis, strengthening the interpretation of TiO₂-based solar photocatalytic systems. In conclusion, solar photocatalysis using TiO₂ and the optimization of operational variables constitute an effective treatment strategy that takes advantage of solar irradiation as the primary energy source, thereby reducing dependence on conventional artificial UV irradiation. Within the scope of this study, the combination of solar radiation, continuous aeration and appropriate operating conditions demonstrated promising potential for the treatment of textile wastewater containing persistent dyes. Full article

New approaches to the band gap engineering of ZnO:Fe/SnO₂ nanocomposites are developed in this study. The main idea is to control the band structure of the material by varying the modifier (iron) content during the preparation of the film-forming sol and the co-evolution of its components. Experimental X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy-Dispersive X-ray Spectroscopy (EDX) data demonstrate that materials with controlled crystallite size and hierarchical morphology can be obtained with Fe contents ranging from 1 to 6 at.%. For the first time, a combined analysis of XPS data and Tauc plot band gap measurements demonstrates preferential doping of zinc oxide within the composite studied. It is also found that the formation of type II heterostructures at Fe concentrations of up to 4 at.% takes place. The authors suggest that the formation of a Z-scheme heterostructure occurs at iron contents of 5 and 6 at.%, and X-ray amorphous phases act as charge transfer mediators. It is established that the photocatalytic properties of the material are determined by the interrelations between the band structure of the material and the spectral characteristics of the radiation sources, while optical power is not a dominant factor. Using the ZnO/SnO₂ nanocomposite ensures 98.12% decomposition of Brilliant Green in 120 min under short-wave UV radiation, while using the photocatalytic material containing 6 at.% iron ensures 95.84% degradation of the dye in the same time under soft UV radiation. Employing a low-power lamp simulating the solar spectrum in the 380–780 nm range enables 24.91% decomposition of the organic pollutant when using ZnO:Fe(5 at.%)/SnO₂ as a photocatalyst. Full article

Solar ultraviolet (UV) radiation is a major contributor to skin damage, making the regular use of broad-spectrum sunscreens essential for effective photoprotection. However, the long-term efficacy of sunscreen formulations is limited by the photoinstability of some organic UV filters, particularly avobenzone. Licuri oil (Syagrus coronata) is a naturally derived Brazilian palm oil that represents a promising alternative to medium-chain triglycerides (MCTs) as an oily core for polymeric nanocapsules. Therefore, this study aimed to develop Eudragit^® RS 100-based cationic nanocapsules using licuri oil for avobenzone encapsulation and to incorporate them into hyaluronic acid (HA) or xanthan gum (XG) hydrogels. The nanocapsules ranged from 125 to 158 nm, with a polydispersity index (PDI) of less than 0.2, positive zeta potential (+11 to +13 mV), and encapsulation efficiency above 98%. After 48 h of UVA exposure, the nanocapsule formulations retained 51% and 52% of their initial avobenzone content for the licuri oil- and MCT-based systems, respectively, compared with only 10% for free avobenzone, indicating a marked improvement in photostability following nanoencapsulation. Additionally, licuri oil nanocapsules exhibited increased antioxidant activity compared to MCT-based nanocapsules in both DPPH and ABTS assays. The nanocapsule suspensions were classified as non- to slightly irritating in the Hen’s Egg Test–Chorioallantoic Membrane (HET-CAM) assay. After incorporation into the hydrogels, the resulting formulations exhibited pseudoplastic and thixotropic behavior, with HA-based hydrogels providing higher UV absorption than XG-based hydrogels. Furthermore, no transdermal permeation of avobenzone was observed from either the HA- or XG-based hydrogel formulations, and the HA hydrogel containing licuri oil nanocapsules showed higher stratum corneum retention. These findings demonstrate the potential of licuri oil as an effective alternative to MCTs as the oily core of polymeric nanocapsules for topical formulations containing encapsulated avobenzone. Full article

Greenhouses in subtropical and tropical regions must be designed as agricultural engineering systems adapted to local climates, rather than simply replicating the “insulation” models of temperate areas. Under extreme climatic conditions such as persistent high temperatures, intense solar radiation, high humidity, heavy rainfall, and frequent extreme winds, greenhouses transform from enclosed insulation layers into selective climate filters, mitigating crop stress while maintaining close contact with the outdoor environment. This paper summarizes how these climate drivers are reshaping the use, structure, and control concepts of greenhouses, emphasizing that the performance of warm-zone greenhouses depends primarily on heat dissipation, humidity management, and biohazard control, rather than heating and insulation. In this review, we analyze the climatic boundary conditions that define warm-climate conservation cultivation, including long-term overheating risk, high UV radiation, vapor pressure deficit, and suppressed condensation tendency, as well as storm-induced uplift and dynamic loads. These constraints necessitate unique structural forms: tall, lightweight, well-ventilated building types with large roof and side openings, roof geometries that facilitate rainwater runoff, sophisticated drainage systems, and corrosion-resistant materials suitable for humid and coastal environments. Because insect netting significantly reduces ventilation, pest control and temperature regulation become co-design issues, requiring oversized vents, optimized airflow paths, and hybrid roof–mesh structures. Ventilation is considered the primary climate-control mechanism, supplemented by passive cooling measures such as shading and radiation/optical management (e.g., diffuse films and near-infrared-selective films). Active evaporative cooling is considered a conditional measure due to humidity limitations and disease risks. This paper also integrates the impacts on specific crops (fruits and vegetables, leafy greens, and orchids). It highlights emerging trends: typhoon-resistant and adaptive geometries, computational fluid dynamics (CFD)-based design, and sensor-rich IoT/digital twin control frameworks. These principles collectively establish a coherent design framework for achieving resilient, resource-efficient greenhouse production in warm climates. Full article

Cutaneous melanoma and basal cell carcinoma (BCC) represent the two primary malignancies driven by solar ultraviolet (UV) radiation. To map the spatial topology and distance dependence of their mutational signatures, we deployed new analytical bioinformatics workflow utilizing two convergent strategies: a data-driven read-level phasing framework to discriminate between collateral mutational events versus independent ones and a hypothesis-driven spatial permutational simulation model to capture density-dependent local deviations. A whole-genome analysis employing this framework unexpectedly reveals two fundamentally distinct lesion-processing landscapes, present in both BCC and melanoma. While independent mutations consistently reproduce canonical UV signatures (SBS7a–c) in both tumor types, collateral mutations tell a distinct and more varied narrative between BCC and melanoma. These collateral mutations are unusually abundant for non-UV characteristics, such as age-related SBS1 and SBS5, and display a notable 3′ to 5′ asymmetry near UV-induced lesions in pyrimidine dimers. We also demonstrated that BCC displays a pronounced enrichment of dinucleotide base substitutions flanking UV-signature sites on the 3′ side, particularly CA>TG and CG>TA changes. Ultimately, these topological patterns in both tumors indicate that a primary photoproduct seeds secondary mutagenesis within its local chromatin environment, dramatically altering our understanding of UV-induced lesion processing. Full article

This paper presents the design, construction, and experimental evaluation of a low-cost, portable solar tracking system for monitoring ultraviolet solar radiation in real time. It integrates a Raspberry Pi Zero 2W as the embedded control unit, an AS7331 spectral sensor to measure UVA, UVB, and UVC irradiance, two 270° servomotors to position the system toward the sun, an NEO-6M GPS module to geolocate the system, and a DS3231 real-time clock to synchronize the time. To enable autonomous outdoor operation, a multistage power supply architecture based on a solar panel, a rechargeable battery, and LM2596 and MP1584EN DC-DC regulators was implemented. The tracking algorithm uses astronomical equations to estimate the solar azimuth and elevation and updates the sensor orientation during daylight hours. This allows the UV sensor to remain approximately normal to the incoming solar radiation. Experimental tests were conducted in Arequipa, Peru. The recorded data included UVA, UVB, and UVC irradiance; sensor temperature; geographic coordinates; time; and solar angles. The measured UV profiles exhibited the anticipated diurnal behavior: maximum values around solar noon, higher UVA levels than UVB levels, and minimal UVC levels due to atmospheric absorption. We compared the radiometric response with reference information from EarthKit, PVGIS 5.3, SAMPA, and a Davis Vantage Pro 2 weather station. We evaluated the solar positioning performance against Stellarium, NOAA, and the NREL Solar Position Algorithm. Across the complete five-day validation at three daily evaluation times, the maximum percentage errors were 0.0584% for azimuth and 0.5059% for elevation relative to the NREL SPA, NOAA, and Stellarium reference calculations. The results demonstrate that the proposed system constitutes an embedded, portable, autonomous, and low-cost platform for in situ monitoring of solar ultraviolet radiation. Due to its modular architecture, georeferencing capability, time synchronization, and independent power supply, the prototype can be used as a mobile measurement unit or as part of a distributed network of UV stations at various locations in Arequipa. In this regard, the system enables multipoint measurement campaigns, complements fixed weather stations, validates solar models, and generates local experimental data for the spatial and temporal assessment of the solar UV resource under real-world field conditions. Full article

Background: Solar ultraviolet (UV) radiation is a major contributor to skin damage, driving the demand for safer and more sustainable photoprotective systems. Mycosporine-like amino acids (MAAs) have emerged as promising natural UV filters due to their strong absorption and photostability; however, their application is limited by poor chemical stability in aqueous environments. Objective: The present study aimed to develop and optimize a nanoemulsion-based lip balm incorporating a MAAs-rich extract from Catenella sp., addressing stability limitations while enhancing photoprotective performance. Methods: A MAAs-rich extract was obtained and characterized by UHPLC-DAD, followed by cytotoxicity evaluation in NIH-3T3 fibroblasts and stability assessment under stress conditions. A water-in-oil (w/o) nanoemulsion was rationally developed using pseudo-ternary phase diagrams and optimized through a Box–Behnken experimental design, considering aqueous phase, surfactant mixture, and sonication time as key variables. The optimized nanoemulsion was subsequently incorporated into a lip balm matrix, which was formulated and optimized using a mixture design approach to evaluate thermal, mechanical, and sensory properties. Results: The extract exhibited a high MAAs content (9.53 mg g⁻¹ DW) and low cytotoxicity (IC₅₀ > 100 µg/mL), but pronounced hydrolytic instability, particularly under alkaline conditions, while remaining photostable. The optimized nanoemulsion achieved a droplet size below 200 nm and low polydispersity (PDI < 0.3). Importantly, incorporation of MAAs into nanoemulsion significantly enhanced the in vitro sun protection factor (SPF), increasing from 16.1 (extract) to 35.4, while maintaining broad-spectrum UV coverage (λc = 380 nm). The blank nanoemulsion also contributed to UV attenuation, indicating a synergistic effect of the colloidal system. The optimized lip balm formulation (33% beeswax, 40% nanoemulsion, 22% shea butter, 1% candelilla wax, 4% carnauba wax) demonstrated suitable melting behavior, mechanical resistance, and high sensory acceptance. Conclusions: This study demonstrates that nanoemulsion-based structuring combined with statistical formulation design provides an effective strategy to stabilize MAAs and enhance their photoprotective efficacy, supporting the development of high-performance, natural sunscreen products. Full article

Perovskite solar cells (PSCs) have emerged as a disruptive photovoltaic technology for aerospace and extreme environment applications, driven by their substantial power-to-weight ratio and mechanical flexibility. However, continuous operation under harsh conditions, characterized by the AM0 spectrum, deep vacuum, extreme thermal cycling, and ionizing radiation, exposes the fundamental thermodynamic instability of traditional organic–inorganic hybrid perovskites. This comprehensive review systematically synthesizes 131 recent studies to provide a holistic framework for designing ultrastable, radiation-hardened PSCs. We critically examine the underlying degradation mechanisms, including vacuum-induced volatile desorption, UV-triggered halide segregation, and thermomechanical fracture at buried interfaces. To overcome these critical barriers, we highlight advanced engineering strategies: the transition to all-inorganic CsPbX₃ and lead-free double/chalcogenide perovskites (e.g., Cs₂SnI₆, CaHfS₃), the implementation of dopant-free inorganic transport layers coupled with self-assembled monolayers (SAMs) for cascade band alignment, and the integration of polymeric scaffolds for fracture energy toughening. Furthermore, we emphasize the imperative shift toward solvent-free vacuum deposition techniques (ALD, PLD). A distinctive focus of this review is the integration of Artificial Intelligence; specifically, we evaluate Deep Learning architectures, such as Long Short-Term Memory (LSTM) networks, for predictive State of Health (SOH) monitoring, underscoring the vital transition from simulated to empirical datasets. Finally, coupled with Material Flow Cost Accounting (MFCA), this review outlines a strategic roadmap for the commercialization and deployment of autonomous, self-diagnosing photovoltaic platforms in next-generation satellite and deep-space missions. Full article

Background: Solar dermatitis (SD) is an inflammatory skin disease caused by excessive exposure to ultraviolet (UV) radiation. Gastrodia elata (GE) is a medicinal and edible plant with broad pharmacological activities; however, the polarity distribution of its active components and their specific mechanisms of action in SD remain incompletely understood. Methods: Different polarity fractions of GE-petroleum ether extract (PEE), ethyl acetate extract (EAE), and n-butanol extract (NBAE) were prepared and evaluated in a UVB-induced SD mouse model. We integrated metabolomics, network pharmacology, molecular docking, molecular dynamics simulations, and molecular biology techniques to identify key active ingredients and regulatory mechanisms. Results: The EAE group significantly ameliorated epidermal thickening and collagen damage in SD mice. Mechanistically, EAE and its active component luteolin (LUT) likely suppressed abnormal activation of the JUN pathway (binding energy: −9.1 kcal/mol), leading to downregulation of the pro-inflammatory cytokines tumour necrosis factor-alpha and inerleukin-1 beta. Conclusions: The EAE fraction alleviates SD through multi-component, multitarget synergistic effects, with LUT as a core bioactive component that inhibits the JUN pathway to mitigate skin inflammation and oxidative damage. EAE also accelerated SD recovery by modulating critical metabolic pathways, including arginine biosynthesis and terpenoid backbone biosynthesis. These findings identify EAE and LUT as promising candidate therapeutics for SD. Full article

Surface solar ultraviolet (UV) radiation represents an essential component of shortwave solar radiation, with important implications for atmospheric chemistry and climate studies. Reliable, high-quality records of surface solar UV radiation are essential for UV-related research and applications; however, ground-based UV observations remain sparse worldwide. This study presents a novel broadband parametric model, based on physical principles, for estimating solar UV irradiance ($0.280–0.400 \mu \mathrm{m}$) under clear-sky conditions. The model is computationally efficient and suitable for practical applications. The proposed approach is based on the SMARTS2 spectral radiative transfer model and employs an interdependent integration scheme to derive broadband UV irradiance from spectrally resolved shortwave radiation. The model performance is evaluated against high-quality measurements from the Baseline Surface Radiation Network (BSRN) and compared with an established parameterization. The proposed model demonstrates improved performance at both validation sites, reducing the mean nRMSE from 8.88% to 7.64% at Izaña and from 60.69% to 29.24% at Payerne, while also substantially decreasing the bias under more challenging atmospheric conditions, although the nRMSE at Payerne remains relatively high. These results highlight the potential of the proposed approach as an efficient and physically consistent tool for clear-sky UV irradiance estimation. Full article

Brazil is characterized by high levels of solar exposure, which may compromise skin health due to ultraviolet radiation (UVR), particularly among individuals with darker skin tones who often underuse photoprotective measures. Although darker skin has been hypothesized to exhibit greater resistance to UVR, robust evidence remains limited. This study aimed to investigate the susceptibility of the stratum corneum (SC) of Black individuals to UV-induced lipid peroxidation using the HPLC–TBARS–EVSC protocol. SC samples were collected from the forearms of nine participants by tape stripping and subsequently exposed to an artificial UV radiation source. Lipid peroxidation was quantified through the detection of the malondialdehyde-thiobarbituric acid (MDA-TBA₂) adduct using high-performance liquid chromatography. Following UV exposure, a statistically significant increase in lipid peroxidation was observed, corresponding to an approximate 297% elevation in MDA-TBA₂ levels (p < 0.05). These findings demonstrate that the SC of Black skin is susceptible to UV-induced oxidative damage under the tested conditions. The results support the use of phototype-independent biochemical markers to assess photodamage and reinforce the need for effective photoprotection strategies in individuals with darker skin tones. 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

In this study, density functional theory (DFT)-based investigations are carried out using the CASTEP code. The plane-wave pseudopotential method is used to explore the multifunctional properties, including the structural, electronic spectra, thermo-mechanical and hydrogen storage properties, of hydrogen-rich mixed-anionic (Li₃H₄N₂X, where X = F, Cl, Br, and I) halides. The exchange–correlation interactions are treated within the generalized gradient approximation (GGA) using the Perdew–Burke–Ernzerhof (PBE) functional, while the hybrid HSE06 function is used for accurate band gap predictions. Moreover, the optical properties of the halides are analyzed under the influence of UV–Vis radiation instances. The band gap values of these orthorhombic-structured halides lie in the visible-to-UV regions of radiation, with values of 2.97 eV, 3.12 eV, 3.06 eV and 3.28 eV, respectively. Such band gap values allow these materials to absorb nearly 75% to 90% of incoming radiation, with absorption values around (10⁵ cm⁻¹). These favorable opto-electronic responses make these halides suitable for solar radiation energy conversion applications. Stable thermodynamic responses and the mechanical nature of the mixes (brittle for Li₃H₄N₂Br and ductile for the rest) reveal their practical applicability for flexible photonics. Moreover, due to the presence of rich hydrogen atoms, the Li₃H₄N₂F halide exhibits a gravimetric ratio of around 6.0 wt%, which is higher than the standard (5.5 wt%) value defined by the US DOE. Similarly, GHSC values of 2.5 wt% for Li₃H₄N₂I, 3.5 wt% for Li₃H₄N₂Br, and 5.0 wt% for Li₃H₄N₂Cl are reported; these values indicate that these compounds possess strong potential for use in the hydrogen fuel cells required in light-duty vehicles. Full article

In this work a study about the behavior of nanomaterial-based innovative transparent electrodes is presented, with a special focus on graphene, for space photovoltaic applications, in particular their transparency and the efficiency of the final device. The efficiency of a solar cell is characterized by referring to Power Conversion Efficiency and External/Internal Quantum Efficiency. Starting from the literature results, it is possible to observe that solar cells realized by innovative nanomaterial-based transparent electrodes show promising results in terms of efficiency in the Earth environment. It is known that the space environment is characterized by extreme conditions including high-energy radiation, strong temperature variations and high vacuum, which can damage materials and, consequentially, influence their performances. Among all the properties like transmittance and sheet resistance, which are the main requirements for a good transparent electrode, could change their value and, therefore, influence the efficiency of the solar cell adopting this kind of electrode. In this paper, a theoretical analysis on the effects of high-energy radiation on the transmittance of graphene layers is given, leading to the observation that in the UV frequency range, it shows a sharp fall. Moreover, the effect of temperature varying is studied by an theoretical analysis on the resistivity of the twisted graphene bilayer. It is possible to observe that, in this configuration, the system moves from a superconductor to a metal, according to temperature and twist angle. This represents a starting point to have good efficiency of solar devices in a space environment by keeping high the transparency of their electrodes. Full article

This research investigates the fundamental impact of the photochemical effect of sunlight on the oxidative dissolution of chalcopyrite (CuFeS₂) in sulfate-oxidizing media under mild conditions and circumneutral pH. Beyond its traditional role as a thermal or electrical energy source, this study explores solar light (UV-Vis-NIR) as a photochemical reagent capable of driving the in situ generation of reactive sulfur species to assist the conventional oxidative dissolution pathway. The interaction at the mineral–solution interface under UV-Vis radiation was investigated using a laboratory-scale solar-assisted PS/TiO₂/UV-Vis-NIR system, employing persulfate (S₂O₈²⁻) as a radical precursor and TiO₂ (Aeroxide^® TiO₂ P25) as a photocatalyst. The findings demonstrate that solar exposure increases the system’s electrochemical potential and induces pH changes, which are critical for overcoming the inherent refractoriness of CuFeS₂ at near-neutral pH. This study demonstrates that integrating UV-Vis-NIR radiation serves as a synergistic catalyst in oxidative hydrometallurgical processes, enhancing Cu extraction yields to 14%–19% within 5 h of exposure at the laboratory scale. The use of natural light could offer a synergistic pathway to augment the efficiency of cleaner leaching technologies. These findings suggest that solar radiation could serve as a promising assistant to address kinetic limitations during the oxidative dissolution of complex sulfide ores under ambient conditions. Full article