Artificial Ultraviolet Research Articles

In vitro photoprotective efficacy and photostability of synthesized star-shaped ZnO nanoaggregates associated with ethylhexyl methoxycinnamate and butyl methoxydibenzoylmethane

The heightened susceptibility to skin cancer correlates with exposure to ultraviolet (UV) radiation, which can induce various cutaneous injuries. Inorganic UV filters, like zinc oxide (ZnO), are extensively utilized in sunscreens owing to their capacity to scatter and reflect UV radiation. The efficacy of inorganic UV filters can be augmented across a wider spectrum through synergistic combinations with other active compounds, such as organic UV filters. In this study, we synthesized and evaluated the in vitro effectiveness of star-shaped ZnO nanoaggregates. The samples were obtained employing a simple and greener precipitation method in an aqueous solution. The synthesized ZnO nanoaggregates were characterized through X-ray diffraction, UV/Vis spectroscopy, and transmission electron microscopy. The characterization suggests the aggregation of nanocrystals, with hexagonal wurtzite geometry, enabling the formation of star-shaped particles. The irregular (non-flat) surface and high surface area combined with light absorption in the UVA region make the material susceptible to the application of sun protection. Sunscreens formulated with the synthesized ZnOng in conjunction with ethylhexyl p-methoxycinnamate (EHMC) and/or butyl methoxydibenzoylmethane (BMDBM) were evaluated for in vitro sun protection factor (SPF) and critical wavelength (cλ) using diffuse reflectance spectrophotometry with an integrated sphere. Photostability assessments were also conducted using artificial UV radiation. Sunscreen formulations containing ZnOng in combination with EHMC and BMDBM exhibited a substantial increase in in vitro SPF, approximately 990 % (from SPF 26 to 285). Furthermore, the synthesized ZnOng demonstrated higher in vitro efficacy compared to commercial ZnO active ingredients. Although all samples experienced reductions in SPF values during the photostability assay, ZnOng + EHMC + BMDBM retained a broad-spectrum profile (SPF > 15 and cλ > 370 nm). Based on the distinctive properties and in vitro performance of star-shaped ZnOng, we propose that this synthesized inorganic UV filter could serve as an alternative for enhancing the SPF of sunscreen systems while reducing the concentrations of organic UV filters.

Harnessing Heavy-Atom Effects in Multiple Resonance Thermally Activated Delayed Fluorescence (MR-TADF) Sensitizers: Unlocking High-Performance Visible-to-Ultraviolet (Vis-to-UV) Triplet Fusion Upconversion.

Ultraviolet (UV) light plays a crucial role in various applications, but currently, the efficiency of generating artificial UV light is low. The visible-to-ultraviolet (Vis-to-UV) system based on the triplet-triplet annihilation upconversion (TTA-UC) mechanism can be a viable solution. Metal-free multiple resonance thermally activated delayed fluorescence (MR-TADF) materials are ideal photosensitizers (PSs) apart from the drawback of high photoluminescence quantum yields (PLQYs). Herein, we systematically investigated the impact of the heavy-atom effect (HAE) on the MR-TADF sensitizers. BNCzBr was then synthesized by incorporating a bromine atom into the skeleton of the precursor BNCz. Impressively, the internal HAE (iHAE) leads to a significantly decreased PLQY and a remarkably increased intersystem crossing quantum yield (ΦISC). Consequently, a higher upconversion quantum efficiency of 12.5% was realized. While the external HAE (eHAE) harms the UC performance. This work guides the further development of MR-TADF sensitizers for high-performance Vis-to-UV TTA-UC systems.

Low UV radiation influenced DNA methylation, gene regulation, cell proliferation, viability, and biochemical differentiation in the cell suspension cultures of Cannabis indica

The effect of low artificial Ultraviolet (UV) on the DNA methylation remains controversial. This study addresses how differential photoperiods of UV radiation affect the biochemical and molecular behaviors of Cannabis indica cell suspension cultures. The cell suspensions were illuminated with the compact fluorescent lamps (CFL), emitting a combination of 10% UVB, 30% UVA, and the rest visible wavelengths for 0, 4, 8, and 16 h. The applied photoperiods influenced cell morphological characteristics. The 4 h photoperiod was the most effective treatment for improving biomass, growth index and cell viability percentage while these indices remained non-significant in the 16 h treatment. The methylation-sensitive amplified polymorphism (MASP) assay revealed that the UV radiation was epigenetically accompanied by DNA hypermethylation. The light-treated cells significantly displayed higher relative expression of the cannabidiolic‌ acid synthase (CBDAS) and delta9-tetrahydrocannabinolic acid synthase (THCAS) genes about 4-fold. The expression of the olivetolic acid cyclase (OAC) and olivetol synthase (OLS) genes exhibited an upward trend in response to the UV radiation. The light treatments also enhanced the proline content and protein concentration. The 4 h illumination was significantly capable of improving the cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC) concentrations, in contrast with 16 h. By increasing the illumination exposure time, the activity of the phenylalanine ammonia-lyase (PAL) enzyme linearly upregulated. The highest amounts of the phenylpropanoid derivatives were observed in the cells cultured under the radiation for 4 h. Taken collective, artificial UV radiation can induce DNA methylation modifications and impact biochemical and molecular differentiation in the cell suspensions in a photoperiod-dependent manner.

Occupational Exposure to Artificial Ultraviolet Radiation from Welding in Australia.

Artificial ultraviolet radiation (UVR) is produced during welding and can cause damage to both the eyes (ocular) and the skin (dermal). We aimed to investigate the protection used by welders to reduce their exposure to ocular and dermal UVR. We conducted a cross-sectional online survey in Australia that asked welders about their welding tasks and the control measures they used to protect against UVR exposure. There were 634 respondents, of whom 411 undertook welding themselves, 36 supervised other welders, and 130 both supervised and welded. Dermal UVR exposure occurred in 7.8% of welders and 14.4% of supervisors, whereas ocular UVR exposure occurred in 16.8% of welders and 33.1% of supervisors. The use of personal control measures was much lower among supervisors than welders; however, the presence of warning signs or barriers was reported more often by supervisors. Despite the well-known acute and chronic effects of exposure to UVR from welding, there are still many welders and supervisors who do not use adequate protection.

Investigating physiological responses of Wild Rocket subjected to artificial Ultraviolet B irradiation

Utilization of ultraviolet-B radiation (UV-B) is a way to encourage the accumulation of phytochemicals such as glucosinolates, carotenoids, phenolics and flavonoids in plants. In the current research, UV-B treatments were performed, as a possible elicitation strategy to promote the secondary metabolites accumulation in wild rocket (Diplotaxis tenuifolia (L.) DC). After performing the destructive analysis, it has been found that the concentration of chlorophyl a and b as well as carotenoids decreased in response to the UV-B stress. Thiobarbituric acid reactive substances (TBARS) assay has been performed to investigate the membranes damage caused by the UV-B radiation. The analyses confirmed that the highest UV-B tested dose induced the greater damage. Interestingly, an increase of phenolic index, and an accumulation of anthocyanins and glucosinolates has been recorded under the successive exposure of varying UV-B doses. The total sugars, reducing sugars and sucrose buildup were also remarkable. Non-destructive analysis revealed a decline in the overall performance of the UV-B treated plants as well as the maximum quantum efficiency of photosystem II. A decrease in the chlorophyll estimates while an enhanced flavanols and anthocyanins were observed through non-destructive readings. Results of this study not only provided a feasible UV-B dose selection and supplementation for the wild rocket but also the understanding about enhanced phytochemical accumulation in plants against UV-B stress.

Assessment of tumoral and peritumoral inflammatory reaction in cutaneous malignant melanomas.

Skin cancer is one of the most common types of cancer, with an increasing worldwide incidence in recent decades. The main risk factor for increasing the skin cancer incidence is ultraviolet (UV) radiation. Of the two major forms of skin cancer (melanomas and non-melanotic cancers), the cutaneous melanoma (CM) is the most aggressive form, causing about 80% of the deaths resulted from this type of tumor. Malignant melanoma develops through malignant transformation of melanocytes in the skin because of prolonged exposure to solar or artificial UV. The malignant transformation of the melanocytes in the skin is accompanied by the presence of a local inflammatory reaction that, in the initial stages of carcinogenesis, would oppose to tumor development. Chronic exposure to UV or other etiopathogenic factors induces chronic inflammation, which, by producing inflammatory molecules (cytokines, chemokines, prostaglandins), constitutes a tumoral microenvironment that favors carcinogenesis, tumor invasion, metastasis, and the presence of neoplastic "mutant cells" that avoid the protective action of the immune system. Using immunohistochemistry techniques, we assessed the intra- and peritumoral inflammatory infiltrate cells in CM. The chronic inflammatory infiltrate presented more intense in the peritumoral stroma compared to the intratumoral one, heterogenous, more intensely composed of lymphocytes, plasma cells, macrophages, and mast cells (MCs), the most numerous cells in the inflammatory infiltrate being T-lymphocytes, plasma cells and macrophages; B-lymphocytes and MCs were in a small number, especially intratumorally. Inflammatory cells had a direct contact with tumor cells, blood vessels, connective matrix, suggesting that the inflammatory microenvironment plays an important role in carcinogenesis, tumor invasion, local angiogenesis, and tumor metastasis.

Sunlight Exposure and Protection Behavior as Prevention of Skin Cancer in Nursing Students

Background: Skin cancer ranks fifth in the world. Melanoma, a type of skin cancer, ranks 23rd in Indonesia. Meanwhile, deaths caused by skin cancer are more than half of the number of new cases in Indonesia. Indonesia is a country that lies across the equator. It makes Indonesia have longer exposure to sunlight and a higher UV index. This study aims to describe the sunlight exposure level and protection behavior among nursing students.Methods: The samples of this study were 248 respondents from the Faculty of Nursing, Universitas Padjadjaran, who were recruited with a convenience sampling technique. Data were collected using a modified Sun Exposure Behaviour Inventory (SEBI). The data were processed using SPSS statistical software to determine behavioral descriptions and exposure to sunlight. Then, the result of the data analysis was performed with descriptive analysis (frequency and percentage).Results: The result of this study showed that most of the respondents (84.3%) always used longsleeved clothes to cover their shoulders. Most respondents (85.9%) used sunscreen with a Sun Protection Factor (SPF) of 15 or more, and more than half of the respondents (68.5%) used sunscreen that can protect from Ultraviolet A (UVA) and Ultraviolet B (UVB). Most respondents (76.2%) never spent time under natural or artificial Ultraviolet Radiation (UVR) to get the desired brown skin. More than half of the respondents (66.9%) had never sunbathed in the last 12 months. Conclusions: More than half of the respondents had adequate protective behavior against sun exposure and had moderate sun exposure. Using sunscreens with a higher SPF has shown a stronger preventive effect. Therefore, regular use of sunscreen can decrease the risk of skin cancer.

Effect of an Emollient Emulsion Containing 15.0% of Caprylic/Capric Triglyceride on the Urocanic Acid of the Stratum Corneum.

Natural moisturizing factor (NMF) includes several compounds in the stratum corneum (SC), among them, urocanic acid (UCA). Ultraviolet (UV) exposure turns the trans-UCA of the SC into its cis isomer. We investigated the impact of a topical emollient emulsion treatment on the UCA isomers of the SC exposed to artificial UV stress. Aliquots of emollient emulsion were applied in healthy subjects for 2 h on delimited areas of the volar forearm, then, the SC was removed by tape stripping. Tapes were irradiated in a solar simulator chamber and a high performance liquid chromatograph was used to quantify UCA isomers from stripped SC extract. The amount of both UCA isomers were almost twice higher in the SC treated with the emollient emulsion. We also observed that the UV irradiation elevated the amount of the cis/trans UCA ratio on the SC (non-treated and treated), suggesting that the emollient sample was not able to avoid the UCA isomerization. The in vivo tests corroborated with the UCA data obtained ex vivo, since we found an increase in the superficial skin hydration with respective reduction of the TEWL, probably occurring by the occlusion performed by the emollient emulsion containing 15.0% w/w of caprylic/capric triglyceride.

Genotoxic risk assessment of solar UV radiation in tadpoles from Brazilian wetlands

Solar ultraviolet (UV) radiation is an environmental genotoxic factor linked to amphibian decline. Here we assessed the genotoxic risk of UVB and UVA exposure for tadpoles from open ponds in southern Brazil, a mid-latitude region influenced by stratospheric ozone depletion. Daily UV doses were measured on the surface of a pond in Taim Ecological Station (TAIM; 32°49’24’’S; 52°38’31’’W) on a cloudless summer day to predict the worst-case scenario for UV-induced DNA damage. Pond descriptors were related to the use of microhabitats by Boana pulchella tadpoles in two ponds over the climate seasons of 2013 and 2014. Our results indicate that shaded microhabitats were more frequent than unshaded ones in autumn, winter, and spring but not in summer. Hence, the penetration of UV radiation into the water of unshaded microhabitats was evaluated through laboratory experiments with artificial UV sources and pond water samples. Physical and biological sensors were applied in the experiments to measure the incident UV radiation and its genotoxic action. By integrating field and laboratory data, we demonstrate that low doses of biologically effective UV radiation reached the tadpoles in autumn, winter, spring, and early summer due to a high proportion of shaded microhabitats and a high concentration of solids in unshaded microhabitats. However, the relative reduction of shaded microhabitats jointly with a declining water level in late summer may have exposed tadpoles to high UV doses. Our experiments also indicate that solar UVB radiation, but not UVA, is primarily responsible for the induction of DNA pyrimidine dimers in organisms living under the surface of aquatic ecosystems. The present work highlights the determinant role of wetland descriptors for minimizing the genotoxic potential of UV radiation and its consequences for amphibians.

Photovoltaic Power Forecasting based on Artificial Neural Network and Ultraviolet Index

The accuracy of photovoltaic (PV) power generation forecast can seriously affect the penetration ability of PV power into the existing power grid, which is one of the key approaches to achieve emission peak, as well as realize carbon neutrality. In the conventional forecasting methods, Global Horizontal Irradiation (GHI), Diffuse Horizontal Irradiance (DHI), temperature, wind speed, rainfall, etc. are considered as the mainly factors to forecast the PV output power, but ignore the impact of PV power generation caused by the whole PV system’s decay over the 25–30 years lifecycle. The ultraviolet (UV) index, which reflects the quantity of 10–400 nm irradiation, has a strong correlation with such decay and power generation. This paper proposes a novel PV power forecasting model that involving UV index in an artificial neural network, using Adam method to optimize the training process with the Keras-tuner employed for optimization of the hyperparameters. Experiments demonstrate that the proposed model achieves more precise performance than conventional methods.

Degradation of DNA in Whole Blood and Semen by UV Radiation and High Temperature at Varying Time Lengths of Exposure

The objective of this investigation was to study the effect of artificial ultraviolet (UV) radiation of varying wavelengths on the degradation of whole human blood DNA and semen over varying time lengths of exposure. DNA degrades rapidly when exposed to environmental factors like high temperature and UV-radiation. The extent of damage done to human DNA in relation to time of exposure to artificial UV and high temperature above 100°C that make blood samples unsuitable for forensic analysis has not yet been determined, and using two methods of extraction the organic and kit methods. The gel electrophoresis was used to appear the bands.

Indoor tanning: Evidence surrounding advertised health claims

Indoor tanning continues to remain common, despite evidence of an increased risk of skin cancer from artificial ultraviolet (UV) radiation. In the hopes of gaining customers, the tanning bed industry has marketed health benefits of indoor tanning such as increased vitamin D production, development of a base tan, enhanced mood, and treatment of certain dermatologic conditions. To better educate their patients, providers need a comprehensive reference reviewing the evidence that support or oppose these claims. In this work, we conducted an evidence-based review of the literature to identify and grade studies that investigate health claims related to UV exposure. Results indicate that there is little evidence to support each of these proposed health benefits. Tanning beds emit primarily UVA radiation, which is relatively ineffective at activating vitamin D or mood enhancing pathways, and the effects are minimal in regard to tanning beds generating a protective base tan or treating dermatologic conditions compared with the increased risk of skin cancer. Health care providers must continue to warn and educate patients about the misleading information propagated by the tanning bed industry as well as about the dangers of artificial UV radiation.

Environmental survival of SARS-CoV-2 – A solid waste perspective

The advent of COVID-19 has kept the whole world on their toes. Countries are maximizing their efforts to combat the virus and to minimize the infection. Since infectious microorganisms may be transmitted by variety of routes, respiratory and facial protection is required for those that are usually transmitted via droplets/aerosols. Therefore this pandemic has caused a sudden increase in the demand for personal protective equipment (PPE) such as gloves, masks, and many other important items since, the evidence of individual-to-individual transmission (through respiratory droplets/coughing) and secondary infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). But the disposal of these personal protective measures remains a huge question mark towards the environmental impact. Huge waste generation demands proper segregation according to waste types, collection, and recycling to minimize the risk of infection spread through aerosols and attempts to implement measures to monitor infections. Hence, this review focuses on the impact of environment due to improper disposal of these personal protective measures and to investigate the safe disposal methods for these protective measures by using the safe, secure and innovative biological methods such as the use of Artificial Intelligence (AI) and Ultraviolet (UV) lights for killing such deadly viruses.

Combined machine learning–wave propagation approach for monitoring timber mechanical properties under UV aging

This study proposes a combined machine learning–wave propagation approach for nondestructive prediction of the modulus of elasticity (MOE) and rupture (MOR) of timber subjected to ultraviolet (UV) radiation. Fir, poplar, alder, and oak wood specimens were subjected to artificial UV aging and assessed using the Lamb wave propagation. Different features including the wave characteristics and the viscoelastic properties of the specimens were obtained from the Lamb wave propagation tests. The extracted features trained a decision tree model for MOE and MOR prediction. The UV radiation caused a decrease in the elastic properties of wood but increased its viscoelasticity. The results also showed a decrease in the wave velocity and an increase in the wave amplitude decay with the UV exposure time. It was revealed that compared with the wave velocity, the wave amplitude decay was better correlated to the MOE of MOR of UV-degraded wood. The MOE and MOR of UV-degraded wood were accurately predicted by the machine learning models fed by the features extracted from the Lamb wave propagation tests, where the shear storage modulus was found as the most important feature for training the models. It was concluded that the proposed approach offers a great tool for in-situ monitoring of wood structures under weathering and photodegradation conditions.

Deposition of Zinc Oxide Coatings on Wood Surfaces Using the Solution Precursor Plasma Spraying Process

In the present work, the solution precursor plasma spray (SPPS) process was used to deposit zinc oxide (ZnO) coatings on wood surfaces using zinc nitrate solution as precursor to improve the hydrophobicity and the color stability of European beech wood under exposure to ultraviolet (UV) light. The surface morphology and topography of the wood samples and the coatings were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The formation of ZnO was detected with the help of X-ray photoelectron spectroscopy (XPS) and by Fourier transform infrared (FTIR) spectroscopy. The FTIR spectra of the coated samples showed the typical Zn–O band at 445 cm−1. According to the XPS analysis, the coatings consist of two different Zn-containing species: ZnO and Zn(OH)2. Variation of the deposition parameters showed that the most significant parameters affecting the microstructure of the coating were the solution concentration, the deposition scan speed, and carrier gas flow rate. The wettability behaviors of the coated wood were evaluated by measuring the water contact angle (WCA). The coatings that completely covered the wood substrates showed hydrophobic behaviors. UV-protection of wood surfaces after an artificial UV light irradiation was evaluated by color measurements and FTIR spectroscopy. The ZnO-coated wood surfaces were more resistant to color change during UV radiation exposure. The total color change decreased up to 60%. Additionally, the FTIR spectra showed that the wood surfaces coated with ZnO had more stability. The carbonyl groups formation and C=C-bonds consumption were significantly lower.

Development of Job Exposure Matrices to Estimate Occupational Exposure to Solar and Artificial Ultraviolet Radiation.

Job exposure matrices (JEMs) are important tools for estimating occupational exposures in study populations where only information on industry and occupation (I&O) are available. JEMs The objective of this work was to create JEMs for solar and artificial ultraviolet radiation (UVR) using a US standardized coding scheme. Using U.S. Census Bureau industry and occupation codes, separate lists of I&O pairs were developed for solar and artificial UVR by a panel of Certified Industrial Hygienists who assigned exposure ratings to I&O pairs with potential exposure. Parameters for exposure included prevalence (P) and frequency (F) for solar UVR and P, F, and intensity (I) for artificial UVR. Prevalence, or percent of all workers employed in an I&O pair who were exposed, was categorically rated: 0 to <1, 1 to <20; 20 to <80, and ≥80. Frequency of exposure, defined by the number of hours per week workers were exposed, was categorically rated: 0 to <5, 5 to <20, 20 to <35, and ≥35 h per week. For artificial UVR only, intensity of exposure was assigned three ratings: low, low with rare excursions, and >low under normal conditions. Discrepant ratings were resolved via consensus. After excluding I&O pairs assigned P and F ratings of 0 (solar UVR) and P, F, and I ratings of 0 (artificial UVR) from the JEM, 9206 I&O pairs were rated for solar UVR and 2010 I&O pairs for artificial UVR. For solar UVR, 723 (7.9% of all rated pairs) had ratings in the highest category for P and F; this group included 45 occupations in varied industries. Construction and extraction occupations represented most of the occupations (n = 20; 44%), followed by farming, fishing, and forestry occupations (n = 6; 13%). For artificial UVR, 87 I&O pairs (4.3% of all rated pairs) had maximum ratings for P, F, and I; these comprised a single occupation (welding, soldering, and brazing workers) in diverse industries. JEMs for solar and artificial UVR were developed for a broad range of I&O pairs in the US population and are available for use by researchers conducting occupational epidemiological studies.

Treatment of Synthetic Wastewater Containing Diethyl Phthalate through Photo-Fenton Method by Box-Behnken Design

Background & Aims of the StudyDiethyl phthalate (DEP) cannot be proficiently degraded by ultraviolet (UV) radiation and hydrogen peroxide (H2O2) oxidation separately; however, the photo-Fenton method is verified to be operative and can completely degrade this pollutant. Currently, advanced oxidation methods have been growing to be employed for the remediation of industrial wastewater. In the present study, the photo-Fenton process investigated the degradation and mineralization of the aqueous solution containing DEP.Materials and MethodsSynthesized wastewater was used in this study. In addition, the effects of operative factors, such as the initial concentrations of H2O2, ferrous ion, and DEP, have been studied. The response surface methodology and Box-Behnken design of experiments were applied to examine the effects of three sovereign variables on the response functions to obtain the optimum circumstances.ResultsThe analysis of variance was carried out to determine the importance of the effects of independent variables on the response function. Various amounts of variables were optimized for the removal of DEP. At optimum conditions (i.e., H2O2 concentration of 400 mg/l, ferrous concentration of 75 mg/l, and DEP concentration of 50 mg/l) and 60 min following the reaction, the rates of degradation efficiency for DEP and chemical oxygen demand (COD) were 100% and 85.3%, respectively.ConclusionAccording to the obtained results, the suggested quadratic model showed good correctness. The statistical analysis of the model indicated that the model was satisfactory to predict the performance of the processes. The obtained findings demonstrated that the photo-Fenton processes can be used for the complete and partial removal of DEP and COD from wastewater, respectively. The benefits of the photo-Fenton process were less sludge formation, fewer chemicals, and time obligation but at the cost of consumed power. The power consumption can be reduced by employing sunlight instead of artificial UV light to a larger amount. The photo-Fenton procedure was influential in the degradation of DEP and can considerably decrease COD.

Ultraviolet radiation and cutaneous melanoma: a historical perspective.

In this article, we summarize the research that eventually led to the classification of the full ultraviolet (UV) radiation spectrum as carcinogenic to humans. We recall the pioneering works that led to the formulation of novel hypotheses on the reasons underlying the increasing burden of melanoma in light-skinned populations. It took long before having compelling evidence on the association between UV and melanoma, in particular, the importance of UV exposure during childhood for both the occurrence of melanoma and death. The role of UVA was established only after 2005. If molecular lesions caused by UV radiation are better known, the precise mechanism by which UV exposure drives melanoma occurrence and progression still needs to be elucidated. More research on the UV-melanoma relationships has led to more evidence-based sun-protection recommendations, especially for children, and to effective control of the artificial UV tanning fashion. Since around 1985-1995, the mortality because of melanoma has started to decrease in younger age groups in most light-skinned populations. If sun protection among children remain on top of public health agendas, there is a fairly great chance that melanoma mortality will stabilize and steadily decrease in all light-skinned populations. The introduction of effective therapies against metastatic disease will improve this reversal in mortality trends.

Layer‐by‐Layer Assembly of Nanofiber/Nanoparticle Artificial Skin for Strain‐Insensitive UV Shielding and Visualized UV Detection

AbstractHere, a strain‐insensitive, durable, and visualized ultraviolet (UV) detectible multilayered artificial UV shielding skin (MUVS‐skin) is demonstrated. The electrospinning of polyurethane nanofibers and electrospraying of TiO2 nanoparticles are alternatingly conducted to assemble the MUVS‐skin. The results show that the stability of UV shielding property under different strains (50%, 100%, 150%, and 200%) is enhanced as more layers are assembled. The ultraviolet protection factor of the strain‐free MUVS‐skin (119 µm) is 10 810 and reaches to 5685 at 200% strain. Moreover, the effective transmittance (at 365 nm) of MUVS‐skin (119 µm) after being stretched for 10 000 cycles at 200% strain is only 0.125%. This stable UV shielding property is ascribed to the low‐level variation in the porosity of the multilayered structure, which originates from the enhanced slippage between adjacent layers. Furthermore, ultraviolet A (UVA) and ultraviolet B (UVB) can be precisely detected as the luminescence of blue and red for the MUVS‐skin integrates with a phosphor layer (MUVS‐skin/P). Owing to the excellent stable UV shielding property, visualized UV detection and durability against cyclic deformation, this MUVS‐skin/P might be extensively applied to the smart wearable artificial skin and protective clothing.

Photostabilizing Efficiency of Acrylic-based Bamboo Exterior Coatings Combining Benzotriazole and Zinc Oxide Nanoparticles

Long-term exposure to ultraviolet (UV) light can degrade and discolor bamboo; thus, coatings to protect it from UV exposure are required, especially for outdoor use. Benzotriazole (BTZ) and zinc oxide nanoparticles (NZnO) are organic and inorganic UV absorbers commonly used in UV shielding coatings. This study investigated the photostabilizing efficiency of acrylic-based bamboo exterior coatings using a combination of BTZ and NZnO. Different film formulations covering bamboo substrates were irradiated with artificial UV light for 500 h to accelerate aging. The UV-shielding effect on bamboo beneath various films was determined by CIELAB color space and Fourier transform infrared (FTIR) analysis. The film effectiveness was analyzed by scanning electron microscopy, wettability, UV-vis spectroscopy, and FTIR-attenuated total reflection (ATR) spectroscopy. Films containing BTZ provided higher resistance to photodegradation and more effectively inhibited photodiscoloration of the bamboo substrates than those prepared solely with NZnO. After 500 h of UV irradiation, the BTZ–NZnO film containing 2 wt % BTZ and 1 wt % NZnO showed the best coating performance. Strong synergistic effects were detected in the BTZ–NZnO coatings, particularly for the 2:1 ratio formulation. This study also demonstrated the potential of combining BTZ and NZnO as additives for developing stable, effective UV-shielding bamboo exterior coatings for outdoor applications.