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Plastic flotation is a promising process for sorting different types of plastics based on differences in wettability. Plastic surface modification is an important step to realize efficient flotation separation of mixed plastics. However, the large number of chemical reagents consumed in the plastic modification process may not only increase the process cost, but also generate new pollutants. This is extremely unfavorable for the large-scale use of plastic flotation to treat plastic pollution. In view of this, it is necessary to develop some novel, clean, and low reagent consumption plastic flotation processes. In our previous work, it was found that the surface wettability of plastics can be regulated based on the photochemical effect on plastic surface. And photochemical effect can be divided into photoaging effect and photo-reconstruction effect. But photoaging-plastic flotation or photo-reconstruction plastic flotation processes can only be used to treat binary or ternary plastic mixtures. Moreover, some processes still require the consumption of a large number of chemical reagents. Therefore, in this work, by combining photoaging effect with photo-reconstruction effect, we successfully developed a clean UV irradiation-plastic flotation process that only use very small amounts of chemical reagents. More importantly, this novel process can be used to separate multi-plastics. This work not only makes up for the shortcomings of our previous work, but also provides a new idea for the treatment of plastic pollution. [ABSTRACT FROM AUTHOR]

Herein, Ag/TiO2/Nylon 6/PMMA catalyst system was developed, and its photocatalytic properties were fully analyzed. XRD, SEM, EDS, and PL analyses were carried out to get information on crystal structure, micromorphology, elemental composition, and band gap energy. Photocatalytic degradation was followed by UV–vis spectrophotometry. The band gap of the catalyst was found to be between 2.51 and 3.1 eV. Up to 80% degradation was achieved under UV light irradiation. No bulk adsorption was observed, which means that the reaction was completely carried by the photocatalytic process. pH 3 value was determined to be suitable for a high rate. Reaction kinetic was determined to be matched with the first-order rate law. The newly developed polymer blend matrix system here may have broad application prospects in the remediation of water resources. [ABSTRACT FROM AUTHOR]

The photodegradation of azithromycin present was carried out in water using H2O2 under UV irradiation. The reaction variables considered in this study were the amount of H2O2 solution and the initial concentration of azithromycin to evaluate the performance of the photodegradation process. The azithromycin degradation was not observed in the dark during stirring for 20 min. The study showed an efficient photodegradation of azithromycin using H2O2 as an oxidant in the presence of UV irradiation. The azithromycin degradation was altered significantly by the pH of the irradiated solution. The degradation was low at an acidic pH and showed an increasing trend as the pH changed to basic. The azithromycin degradation increased with a higher amount (higher concentration) of H2O2. The degradation of azithromycin decreased with a higher concentration of azithromycin in the reacting solution. The highest degradation of AZT was achieved in 1 h using a 1.0 ppm AZT solution containing 3 mL of H2O2. The experimental data obtained were well-fitted to zero-order reaction kinetics. The results of this study were found quite excellent. They showed 100% degradation in 1 h when compared with those reported in the literature, both with photocatalysis using nanomaterials and photolysis using light irradiation and/or H2O2. The UV/H2O2 system was found to be quite efficient for the photodegradation of azithromycin, and this system can be applied to degrade other organic pollutants present in industrial wastewater. [ABSTRACT FROM AUTHOR]

Micro-sized particles of synthetic polymers (microplastics) are found in all parts of marine ecosystems. This fact requires intensive study of the degree of danger of such particles to the life activity of hydrobionts and needs additional research. It is evident that hydrobionts in the marine environment are exposed to microplastics modified by biotic and abiotic degradation. To assess the toxic potential of aging microplastic, comparative studies were conducted on the response of cytochemical and genotoxic markers in hemocytes of the mussel Mytilus trossulus (Gould, 1850) after exposure to pristine and photodegraded (UV irradiation) polystyrene microparticles (µPS). The results of cytochemical tests showed that UV-irradiated µPS strongly reduced metabolism and destabilized lysosome membranes compared to pristine µPS. Using a Comet assay, it was shown that the nuclear DNA of mussel hemocytes showed high sensitivity to exposure to both types of plastics. However, the level of DNA damage was significantly higher in mussels exposed to aging µPS. It is suggested that the mechanism of increased toxicity of photo-oxidized µPS is based on free-radical reactions induced by the UV irradiation of polymers. The risks of toxic effects will be determined by the level of physicochemical degradation of the polymer, which can significantly affect the mechanisms of toxicity. [ABSTRACT FROM AUTHOR]

Solar radiation that arrives on the surface of Mars interacts with organic molecules present in the soil. The radiation can degrade or transform the organic matter and make the search for biosignatures on the planet's surface difficult. Therefore, samples to be analyzed by instruments on board Mars probes for molecular content should be selectively chosen to have the highest organic preservation content. To support the identification of organic molecules on Mars, the behavior under UV irradiation of two organic compounds, undecanoic acid and L-phenylalanine, in the presence of vermiculite and two chloride salts, NaCl and MgCl, was studied. The degradation of the molecule's bands was monitored through IR spectroscopy. Our results show that, while vermiculite acts as a photoprotective mineral with L-phenylalanine, it catalyzes the photodegradation of undecanoic acid molecules. On the other hand, both chloride salts studied decreased the degradation of both organic species acting as photoprotectors. While these results do not allow us to conclude on the preservation capabilities of vermiculite, they show that places where chloride salts are present could be good candidates for in situ analytic experiments on Mars due to their organic preservation capacity under UV radiation. [ABSTRACT FROM AUTHOR]

The present work deals with the optimization of basic fuchsin dye removal from an aqueous solution using the ultraviolet UV/H2O2 process. Response Surface Modeling (RSM) based on Box-Behnken experimental design (BBD) was applied as a tool for the optimization of operating conditions such as initial dye concentration (10–50 ppm), hydrogen peroxide dosage (H2O2) (10–20 mM/L) and irradiation time (60–180 min), at pH = 7.4 under ultra-violet irradiation (254 nm and 25 W intensity). Chemical oxygen demand (COD abatement) was used as a response variable. The Box–Behnken Design can be employed to develop a mathematical model for predicting UV/H2O2 performance for COD abatement. COD abatement is sensitive to the concentration of hydrogen peroxide and irradiation time. Statistical analyses indicate a high correlation between observed and predicted values (R2 > 0.98). In the BBD predictions, the optimal conditions in the UV/H2O2 process for removing 99.3% of COD were found to be low levels of pollutant concentration (10 ppm), a high concentration of hydrogen peroxide dosage (20 mM/L), and an irradiation time of 80 min. [ABSTRACT FROM AUTHOR]

A commercial TEMPO-oxidized cellulose (TOC) and three laboratory-made TOC samples prepared under different conditions were converted to aqueous 0.4% dispersions of TEMPO-oxidized cellulose nanofibrils (TEMPO-CNFs) by high-pressure homogenization in water under the same conditions. The obtained TEMPO-CNF/water dispersions were irradiated with ultraviolet (UV) light for 0–48 h using a high-pressure mercury lamp at a main wavelength of 365 nm. The changes in the light transmittance, viscosity, pH, zeta-potential, and average particle size of the dispersions, and mass recovery ratio, molar mass, and carboxylate content of the acid-insoluble and freeze-dried fractions separated and isolated from the UV-irradiated dispersions were investigated. The results were analyzed in terms of the UV-irradiation time. The dispersion pH, and the mass recovery ratio, carboxylate content, and mass-average degree of polymerization (DPw) of the acid-soluble fraction decreased with increasing UV-irradiation time. This shows that some acid-soluble acidic compounds were formed from the TEMPO-CNFs via UV-induced depolymerization, degradation, and removal of carboxylate groups from the TEMPO-CNFs in water, depending on the UV-irradiation time. The average CNF length, which was determined from atomic force microscopy images, decreased with increasing UV-irradiation time. After UV irradiation of dispersions of the laboratory-made TEMPO-CNFs for 12 h, the average CNF lengths were 130–150 nm and their length distributions were narrower. UV irradiation of TEMPO-CNF/water dispersions is therefore a promising method for efficiently decreasing the dispersion viscosity, DPw, and average CNF length, depending on the TEMPO-CNF properties and UV-irradiation conditions. [ABSTRACT FROM AUTHOR]

The fluorinated titanium dioxide (F-TiO2) hollow spheres with varying F to Ti molar ratios were prepared by a simple one-step hydrothermal method followed by thermal processing. The diameter of the F-TiO2-0.3 hollow spheres with a nominal ratio of F:Ti = 0.3:1 was about 200–400 nm. Compared with the sensor based on pristine TiO2 sensing materials, the F-TiO2-0.3 sensor displayed an enhanced sensing performance toward gaseous formaldehyde (HCHO) vapor at room temperature under ultraviolet (UV) light irradiation. The F-TiO2-0.3 sensor demonstrated an approximately 18-fold enhanced response (1.56) compared to the pristine TiO2 sensor (0.085). The response and recovery times of the F-TiO2-0.3 sensor to 10 ppm HCHO were about 56 s and 64 s, respectively, and a limit-of-detection value of 0.5 ppm HCHO was estimated. The F-TiO2-0.3 sensor also demonstrated good repeatability and selectivity to HCHO gas under UV light irradiation. The outstanding HCHO gas-sensing properties of the F-TiO2-0.3 sensor were related to the following factors: the excitation effect caused by the UV light facilitated surface chemical reactions with analyte gas species; the hollow sphere structure provided sufficient active sites; and the surface fluoride (≡Ti−F) created additional chemisorption sites on the surface of the TiO2 material. [ABSTRACT FROM AUTHOR]

Highly transparent, conductive nanosheets are extremely attractive for advanced opto-electronic applications. Previously, we have demonstrated that transparent, conductive Au nanosheets can be prepared by UV irradiation of Au nanoparticle (AuNP) monolayers spread on water, which serves as the subphase. However, thick Au nanosheets cannot be fabricated because the method is not applicable to large Au NPs. Further, in order to fabricate nanosheets with different thicknesses and compositions, it is necessary to prepare the appropriate NPs. A strategy is needed to produce nanosheets with different thicknesses and compositions from a single type of metal NP monolayer. In this study, we show that this UV irradiation technique can easily be extended as a nanosheet modification method by using subphases containing metal ions. UV irradiation of 4.7 nm AuNP monolayers on 480 µM HAuCl4 solution increased the thickness of Au nanosheets from 3.5 nm to 36.5 nm, which improved conductivity, but reduced transparency. On the other hand, the use of aqueous AgNO3 and CH3COOAg solutions yielded Au-Ag hybrid nanosheets; however, their morphologies depended on the electrolytes used. In Au-Ag nanosheets prepared on aqueous 500 µM AgNO3, Au and Ag metals are homogeneously distributed throughout the nanosheet. On the other hand, in Au-Ag nanosheets prepared on aqueous 500 µM CH3COOAg, AuNPs still remained and these AuNPs were covered with a Ag nanosheet. Further, these Au-Ag hybrid nanosheets had high conductivity without reduced transparency. Therefore, this UV irradiation method, modified by adding metal ions, is quite effective at improving and diversifying properties of Au nanosheets. [ABSTRACT FROM AUTHOR]

The irradiation of water solution of cytidine with UVC light showed that the compound participates in a tautomerism following the kinetics of a first‐order reaction. The PIDA mechanism showed that the proton detachments in the tautomers of cytidine occur through the repulsive 1πσ* excited states and lead to conical intersections S0/S1, whose structures were optimized. More probable is the IRC mechanism, which proceeds along 1nπ* excited state reaction paths. This mechanism includes a water molecule as a catalyst, which assists the phototransformation of amino‐oxo tautomer of cytidine into imino‐hydroxy one. [ABSTRACT FROM AUTHOR]

Polymethylmethacrylate (PMMA) has been irradiated by 365 nm UV wavelength at different exposition times in air and room temperature. The macromolecular modifications induced in the polymer have been investigated using attenuated total reflectance (ATR) coupled to Fourier transform infrared (FTIR) spectroscopy, UV-Visible spectroscopy, surface profiler, wetting ability, and electronic microscopy. The observed chemical, optical and morphological changes occurred as a consequence of the UV irradiation suggest that chain scissions are induced by the UV radiations, with reduction of the IR and visible transmittance, wetting ability and surface roughness. The study of the degradation of PMMA by different times of exposure to UV radiation is investigated with the aim of understanding the effects produced over time on optical devices such as intraocular lenses, optical fibres, protective screens, and instrumental lenses. [ABSTRACT FROM AUTHOR]

Composites of poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) with different mass ratio, containing nano-sized calcium carbonate, benzophenone and triallyl isocyanurate, were prepared by using a double screw extruder, and blown into films by extrusion blow molding. After ultraviolet (UV) exposure at irradiation doses (ID) of 20 J/cm2 and 40 J/cm2, the mechanical, dynamic mechanical and thermal properties of the radiated films were tested and compared with that of the unradiated. The tensile strength of the PLA/PBAT (100/0) film with single PLA phase increased after exposure to UV light, but its fracture energy decreased. In contrast, both the tensile strength and fracture energy of PLA/PBAT (70/30) film with PLA and PBAT co-continuous phases increased after exposure, but both the tensile strength and fracture energy of PLA/PBAT (50/50) film with PBAT continuous phase decreased. The glass transition temperature (Tg) of PLA/PBAT (100/0) film increased after exposure to UV light, but the Tg of both PLA/PBAT (70/30) and (50/50) films unchanged or varied within the error range. The crystallization temperature (Tc) of all the films did not changed after UV exposure, but the crystallizability significantly decreased. It suggested that UV irradiation was a simple and effective technique to simultaneously improve the strength and toughness of the film with PLA and PBAT co-continuous phases. [ABSTRACT FROM AUTHOR]

The article explores the phenomenon of tautomerism in isocytosine when exposed to UVC light. The study found that UVC light caused a specific type of tautomerism in isocytosine in water, with a certain rate constant. Two mechanisms of this tautomerism were investigated, with one being more likely. The research aims to understand the tautomeric behavior of isocytosine and its implications for the stability of pyrimidine nucleobases. The findings provide insight into why cytosine is chosen over isocytosine in nucleic acid macromolecules. [Extracted from the article]

It was shown for the first time that preliminary deuteration of Esherichia coli bacteria with deuterium oxide (D2O) at concentrations from 5 to 10% in a medium leads to an enhancement of the SOS response in the biosensors E. coli MG1655 (pColD::lux) and E. coli MG1655 (pRecA::lux) induced by UV at a dose of 12 J/m2. The biosensors used in this work contain hybrid plasmids carrying the luxCDABE operon of the Photorhabdus luminescens photobacterium, placed under the control of the cda (colD) and recA gene promoters. The induction of genotoxic factors in biosensors indicates the activation of the corresponding E. coli SOS system of gene expression. A simultaneous study of the intensity of luminescence and the cell viability of the E. coli MG1655 biosensor (pCol-lux) bacteria showed that UV irradiation at a dose of 12 J/m2 increases the intensity of luminescence from 2111.1 in a medium without D2O to 5030.3 RLU for 107 viable cells in a medium with D2O. The intensity of luminescence of the biosensor was 2.5 times higher in the medium with deuterium than without it. [ABSTRACT FROM AUTHOR]

Background: Ultraviolet (UV) irradiation has been widely employed to disinfect food, however, the efficacy of UV irradiation in degrading polycyclic aromatic hydrocarbons (PAHs) in smoked sausages has not been explored. In this article, the UV degradation ability of PAHs in smoked sausages was investigated with different UV irradiation conditions, including different irradiation powers, durations and wavelengths. The effects of UV radiation on the quality of sausages were also evaluated, and potential degradation mechanisms were elucidated. Results: The results showed that the irradiation duration was the primary determinant of PAHs degradation, achieving 84.4% and 84.2% degradation rates at 16 W and 32 W power for 30 min, respectively. Among the three UV wavelengths assessed, 254 nm demonstrated a significantly higher degradation rate for benzo[a]pyrene (BaP), PAH4 and PAHs compared to 365 nm and 310 nm. To further explore the degradation mechanism, UV irradiation was combined with water, 0.1 mol/L hydrogen peroxide (H2O2) and 0.1 mol/L ascorbic acid (vitamin C) coatings. The 0.1 mol/L H2O2 coating exhibited the most pronounced degradation effect, suggesting that the highly reactive oxygen hydroxyl radicals (·OH) generated by UV irradiation played a critical role in initiating redox reactions. Conclusion: This systematic investigation paves the way for developing novel strategies to eliminate PAHs or other organic contaminants from smoked sausages. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

UVA and UVB are two main components of solar ultraviolet (UV) radiation. Some studies have reported the impacts of UV irradiation on plant secondary metabolism and plant growth. However, the role of UV irradiation in plant growth and quality in biochar-treated soils is poorly understood. This study aims to investigate the interactive effects of UV irradiation and biochar application on the growth and quality of Pseudostellaria heterophylla (Miq.) Pax, a popular medicinal plant. Three UV irradiation conditions (no UV irradiation, UVA irradiation at 2.5 W/m2 for 12 h/day and UVB irradiation at 0.05 W/m2 for 0.5 h/day) were considered in biochar-free and biochar (3%)-amended soils. The non-UV irradiated biochar-treated group exhibited the highest tuber yield. UVA irradiation reduced the yield improvement efficiency of biochar, while under UVB irradiation, biochar treatment reduced the tuber biomass. This were mainly because the application of high-nutrient biochar increased plant sensitivity to UV radiation. The UVA-irradiated group without biochar treatment exhibited the maximum polysaccharide concentration in the tuber, which was 38% higher than that of the control. Biochar application inhibited polysaccharide synthesis under UV treatment. The saponin concentration in the tuber was enhanced by up to 79% under UV (particularly UVB) irradiation. The coupled UVB and biochar treatment significantly enhanced saponin synthesis. These results indicate the interactive effects of UV irradiation and biochar treatment on P. heterophylla. Therefore, biochar amendment without UV irradiation is suggested to improve the tuber yield of P. heterophylla. UVA (2.5 W/m2 for 12 h/day) treatment is recommended for higher active ingredient concentration. However, the negative effects of UV irradiation on biochar-induced plant growth promotion should be also considered. This research provides a basis for practical large-scale cultivation in the future. [ABSTRACT FROM AUTHOR]

New heterojunction materials (HJs) were synthesized in-situ by molecularly bonding the monomers of a triazine-based covalent organic framework (bulk COF) on the template of exfoliated carbon nitride (g-C3N4). The photocatalysts reduced carbon dioxide to carbon monoxide in aqueous dispersions under UV irradiation. The g-C3N4 showed production of 6.50 μmol CO g−1 h−1 and the bulk COF of 2.77 μmol CO g−1 h−1. The CO yield was evaluated in sustainability photoreduction cycles and their CO2 uptake capacity and isosteric heat of adsorption were estimated. All the heterojunction photocatalysts obtained ameliorated CO production rates compared to the bulk COF. Finally, the influence of the Pt co-catalyst on the photocatalytic activities was determined without the addition of any sacrificial agent, and the COF:g-C3N4 heterojunction with the ratio of 1:10 was proven to be a photocatalytic system with an optimum and selective, CO yield of 7.56 μmol g−1 h−1. [ABSTRACT FROM AUTHOR]

Oxidation by the action of ozone takes place at high rates and involves the reaction of ozone molecules with fatty acid double bonds followed by the formation of stable oxidation products with biological activity. In the present work, a comparative study on sunflower oil oxidized by ultraviolet (UV) light and ozone was carried out. This study involved the chemical characterization of sunflower oil oxidized by UV irradiation and ozonation, in addition to assessing the germicidal activity of oxidized oils obtained under various conditions. The results indicated that under the conditions studied, the increase in the dose of UV irradiation did not produce significant changes in the level of oxidation of the oil. Ozonation promoted the formation of oxygenated compounds at higher rates, increasing in concentration as the applied dosage of ozone increased. The germicidal activity of the oils behaved similarly, with considerably higher activity found in the ozonized oils. [ABSTRACT FROM AUTHOR]

This study examined the effect and stability of ultraviolet B (UV-B) irradiation and subsequent cooking on vitamin D content in commonly consumed mushrooms in Thailand. Eight varieties of mushrooms were exposed to two-sided UV-B lamps for up to 3 h in a patented cabinet, followed by vitamin D content analysis. Thereafter, the four mushroom varieties with the highest vitamin D content were exposed to UV irradiation, cooked, and analyzed for various forms of vitamin D using LC-MS-MS. The results showed that vitamin D2 in all varieties of mushrooms significantly increased (p < 0.05) after UV-B irradiation according to the exposure time. The highest level of vitamin D2 was found in enokitake mushrooms. In addition, 25-OH D2 and vitamin D4 contents increased after UV-B irradiation in enokitake mushrooms. The vitamin D2 true retention in all cooked mushrooms ranged from 53 to 89% and was highest in stir-fried mushrooms. With economic investment, the two-sided UV-B cabinet has the potential to increase the vitamin D content in commercial mushroom production. [ABSTRACT FROM AUTHOR]

The photocatalytic reduction of Cr6+ to Cr3+ in an aqueous solution, using 3 wt% Ag/g-C3N4 in the presence of ethylenediaminetetraacetic acid (EDTA), has been investigated here. The photocatalytic reduction of Cr6+ with pure g-C3N4 was very low. The addition of Ag and EDTA can significantly improve the photocatalytic reduction of Cr6+ using g-C3N4. In the presence of EDTA, the efficiency with Ag/g-C3N4 was better than those with Au/g-C3N4 and Cu/g-C3N4. With EDTA, the reduction rate constant increased from 0.0005 for pure g-C3N4 to 0.12 min−1 for 3 wt% Ag/g-C3N4. By increasing the concentration of EDTA from 0 to 500 mg L−1, the reduction efficiency of Cr6+ increased extremely, and the rate constant raised from 0.008 to 0.12 min−1. The optimal EDTA concentration was 500 mg L−1 for the photocatalyst Ag/g-C3N4. The Ag-EDTA complex may be reduced to metallic silver by the conduction band electrons of g-C3N4. The electron–hole recombination was significantly suppressed by the electron trapping of Ag. EDTA may act in by the formation of Cr3+-complex and the separation of Cr3+ from the g-C3N4 surface and by the valence band hole scavenger of g-C3N4. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), UV–Vis diffuse reflectance spectroscopy (DRS) and photoluminescence spectra (PL) were used to characterize g-C3N4 and Ag/g-C3N4 nanoparticles. A possible mechanism for photocatalytic Cr6+ reduction has also been demonstrated. [ABSTRACT FROM AUTHOR]

Composites of poly(lactic acid) (PLA), poly(butylene succinate) (PBS), and nano‐sized calcium carbonate (CaCO3) with triallyl isocyanurate (TAIC), glycidyl methacrylate and benzophenone (BP) were prepared by using a double screw extruder and blown into films by extrusion blow molding. After exposure to ultraviolet (UV) light at 10, 20, and 40 J/cm2 of irradiation doses, the selected performances of the irradiated films were investigated. UV irradiation increased the tensile performances but had little effect on the thermal behaviors. Scanning electron microscope revealed that UV irradiation enhanced the connection between the two phases of PLA and PBS. The improvement in tensile properties was attributed to the formation of crosslinking during UV irradiation in the presence of TAIC and BP and the enhancement of the interface bonding between the two. However, excessive exposure reduced the elongation at break and fracture energy, attributed to the molecular chain breakage at high doses. On the other hand, the tensile performances improved and the light transmission decreased with increasing the TAIC content up to 2.5 phr after UV exposure at the same irradiation dose. UV irradiation was revealed to be a simple and effective technique to improve the tensile performances of LA/PBS/CaCO3 films with bicontinuous phases. [ABSTRACT FROM AUTHOR]

Organic matter is actively searched on Mars with current and future space missions as it is a key to detecting potential biosignatures. Given the current harsh environmental conditions at the surface of Mars, many organic compounds might not be preserved over a long period as they are exposed to energetic radiation such as ultraviolet light, which is not filtered above 190 nm by the martian atmosphere. Moreover, the presence of strong oxidizing species in the regolith, such as perchlorate salts, might enhance the photodegradation of organic compounds of astrobiological interest. Because current space instruments analyze samples collected in the upper surface layer, it is necessary to investigate the stability of organic matter at the surface of Mars. Previous experimental studies have shown that uracil, a molecule relevant to astrobiology, is quickly photolyzed when exposed to UV radiation under the temperature and pressure conditions of the martian surface with an experimental quantum efficiency of photodecomposition (φexp) of 0.30 ± 0.26 molecule·photon−1. Moreover, the photolysis of uracil leads to the formation of more stable photoproducts that were identified as uracil dimers. The present work aims to characterize the additional effect of calcium perchlorate detected on Mars on the degradation of uracil. Results show that the presence of calcium perchlorate enhances the photodecomposition of uracil with φexp = 12.3 ± 8.3 molecule·photon−1. Although some of the photoproducts formed during these experiments are common to those formed from pure uracil only, the Fourier transformation infrared (FTIR) detection of previously unseen chemical functions such as alkyne C ≡ C or nitrile C ≡ N has shown that additional chemical species are formed in the presence of calcium perchlorate in the irradiated sample. This implies that the effect of calcium perchlorate on the photolysis of uracil is not only kinetic but also related to the nature of the photoproducts formed. [ABSTRACT FROM AUTHOR]

In this work, glycidyl methacrylate (GMA) and trimethylol propanetriacrylate (TMPTA) are employed to adjust the branching structure of poly L-lactide acid (PLLA) during reactive extrusion induced by UV irradiation. The reaction of GMA epoxide with terminal carboxyl or hydroxyl groups at PLLA chain end can introduce C=C groups onto PLLA molecular chains. Chain branching reaction occurred via the free-radical grafting reaction of the vinyl group in TMPTA with both PLLA backbone and the C=C group terminated PLLA induced by UV irradiation. As a result, varied branching levels can be obtained by changing the ratio of GMA and TMPTA. The characterizations of rheological properties and size exclusive chromatograph correlated to the chain branches were performed to evaluate the chain branching extent. The increases in shear viscosity and storage modulus at terminal zone, and the reduced branching degree were observed in the branched PLLA samples. The results from 1H-NMR and FIRT indicate that the grafting reaction of GMA onto PLLA take place successfully. Thus, this study proposes a strategy to adjust LCB-PLA structure using GMA and TMPTA as co-agents, which is of great importance for the industrialization of PLA products. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the impact of UV treatment on the surface functionality and adsorption capacity of biochar, with the goal of enhancing its effectiveness as an adsorbent for toluene. The surface and near-surface functionality and structure of biochar were studied to evaluate the impact of UV treatment by utilizing X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) techniques. Biochar was generated by pyrolyzing wood chips at 900 °C without any oxidant injection in order to increase their carbon content. To boost biochar's adsorption capability, UV irradiation on the biochar is utilized before and during the penetration process. Toluene was selected as the target absorbing material. The equilibrium adsorption capacity and rate were simulated using the Wheeler equation. It was found that the adsorption capacity of biochar increased significantly after pretreatment with ultraviolet light irradiation with a wavelength of 254 nm and an intensity of 280 μW/cm2 and reached a saturated state after 15 h. SEM and XPS showed that the UV-biochar modification technology not only improved the pore structure of biochar, but also increased the content of -O-containing functional groups on the surface of biochar and improved the adsorption capacity of biochar. The experimental results for sample M50_Uu demonstrated significant improvement in adsorption performance. The adsorption saturation time increased by 80%, and the equilibrium adsorption capacity rose from 12.80 mg/g to 54.60 mg/g. The main reason for the adsorption capacity increase by UV treatment is functional group formation, of which rate linearly increases with pretreatment energy until 11 W·hr/gbiochar, after which the increase rate is slow. [ABSTRACT FROM AUTHOR]

To promote the wide application of hydrogen-containing diamond-like films (a-C:H) as solid lubricant materials in aerospace environment, a series of a-C:H, a-C:H doped with Cr elements (Cr/a-C:H) and a-C:H doped with B elements (B/a-C:H) were prepared on the GCr15 steel by non-equilibrium magnetron sputtering technique. The effects of ultraviolet (UV) irradiation on the mechanical and tribological properties of the three DLC films were investigated. UV irradiation was found to cause a decline in hardness and modulus of elasticity, and increased residual stress and surface roughness in all three films. UV irradiation has a minor impact to the coefficient of friction of the three films, but leads to a decrease in wear life. The wear life of Cr/a-C:H films was least affected by UV irradiation. UV irradiation can lead to the breakage of sp3C-H bonds in a-C:H film and B/a-C:H film, resulting in the increase of dangling bonds in the films and the decrease of wear life. In the Cr/a-C:H film, the broken sp3 C-H bond is partially reorganized into sp2 C-H bond, which further exerts the passivation effect of C-H bond, resulting in a smaller decrease in the wear life of the Cr/a-C:H film. [ABSTRACT FROM AUTHOR]

Various surface modification techniques have been developed to improve synthetic polymer surfaces' wetting, adhesion, and printing by adding various functional (polar) groups. UV irradiation has been proposed as a suitable procedure to achieve adequate surface modifications of such polymers, which can be of further use to bond many compounds of interest. The activation of the surface, the favourable wetting properties, and the increased micro tensile strength of the substrate after short-term UV irradiation suggest that such pretreatment can also improve the bonding of the wood-glue system. Thus, this study aims to determine the feasibility of UV irradiation for pretreatment of wood surfaces before gluing and to determine the properties of wooden glued joints prepared in this way. UV irradiation was used to modify variously machined pieces of beech wood (Fagus sylvatica L.) before gluing. Six sets of samples were prepared for each machining process. Samples prepared in this manner were exposed to irradiation on a UV line. Each radiation level had a certain number of passes through the UV line, the more passes, the stronger the irradiation. Thus, the radiation levels were as follows: 1, 5, 10, 20, and 50 passes. The dose (energy delivered on the wood surface) in one pass was 2.36 J/cm2. A wetting angle test with glue, a compressive shear strength test of lap joints, and designation of main failure patterns were used to evaluate the properties of wooden glued joints. Wetting angle test was performed according to EN 828, while the compressive shear strength test samples were prepared and tested following the ISO 6238 standard. The tests were conducted using a polyvinyl acetate adhesive. The study found that UV irradiation before gluing improved the bonding properties of variously machined wood. [ABSTRACT FROM AUTHOR]

Stress the use of safer options such as biological control to avoid the hazards of chemical nematicides. UV irradiation has been used to induce mutations and improve protease overproduction. All mutants recorded significant decreases in nematode-related parameters when compared with the wild type and control. Mutant number one (M1) achieved high protease activity about 2.5 fold. At two concentrations of the wild type Bacillus cereus and their mutants effect on percentage mortality of Meloidogyne incognita juveniles. M1 achieves the highest mortality, 99.33 %, and achieved greatest reductions in the number of juveniles in soil, juveniles/5 g root, galls, and egg-masses recorded 89.76 %, 90.16 %, 85.29 %, and 89.11 %, respectively. M1 achieved the best increase of the growth parameters of plant length, number of branches, number of leaves, and fresh weight of leaves recorded 54.35 %, 71.45 %, 169.44 %, and 256.17 %, respectively. These results are in harmony with those of leaves water soluble-protein electrophoretic patterns after one month and the end of the application, which showed that the plant exposed to M1 exhibited the highest number of bands in both stages of application and appeared unique band at M. W 55kDa after one month of application. [ABSTRACT FROM AUTHOR]

The precursors of polysilazane (PSZ) with different weights were dissolved in xylene to obtain the spinning solution with different concentration. PSZ spinning solution was converted to SiCN(O) fibers by dry spinning, ultraviolet (UV) irradiation cross-linking, and pyrolysis at 1 100 °C. The rheological property of PSZ spinning solution and the UV irradiation cross-linking process of PSZ fibers were investigated by rotational rheometer, FTIR, XPS, SEM and TG. The composition, structure and properties of PSZ fibers and SiCN(O) fibers before and after irradiation were also characterized. The results show that the PSZ spinning solution with the mass fraction of 87% has shear thinning behavior at room temperature, which belongs to the pseudoplastic fluid and has excellent dry spinning performance. The ceramic yield of PSZ fibers increases by 30. 8% compared with the green fibers after 7 h cross-linking under UV irradiation with wavelength of 185 nm. This research has certain exploration significance for the new spinning process of PSZ and the curing treatment of PSZ fibers. [ABSTRACT FROM AUTHOR]

In this study, a flexible graphene microsensor with an embedded microheater was fabricated for nitrogen monoxide (NO) detection. The microsensor and heater were fabricated on a polyethylene terephthalate (PET) substrate through picosecond laser ablation. The results of this study indicated that sensor temperature could be precisely and quickly controlled by adjusting the driving voltage of the microheater. The NO recovery time decreased from 1520 to 283 s (a drastic reduction of 81%) as the sensor temperature increased from 20 to 100 °C. Under ultraviolet (UV) irradiation, the recovery time decreased with the increase in input power of the LEDs. The recovery time decreased by 78% when the distance was 5 mm. In addition, the light-activation of UV-C light-emitting diodes (LED) revealed the promising gas sensing characteristics and visualized their possibility and capabilities. Furthermore, the gas sensor exhibited outstanding durability during cyclic bending tests. An increase in the bending angle decreased sensor response and increased NO recovery time, because sensor deformation influenced sensor conductivity. This study demonstrated the picosecond laser technique to the fabricated flexible graphene microsensor with the heating rate and UV-C irradiation, helping to design next-generation advanced devices for gas detection. [ABSTRACT FROM AUTHOR]

Xeroderma pigmentosum complementation group C (XPC) protein recognizes bulky DNA adducts to initiate global genomic nucleotide excision repair (GG-NER). Humans carrying germline mutations in the XPC gene display strong susceptibility to skin and certain internal cancers. In addition to its role in NER, recent studies have indicated that XPC is also involved in other DNA damage repair pathways and transcription regulation. In this report, we generated a zebrafish xpc knockout mutant. Zebrafish xpc−/− mutant fish develop relative normally and are fertile. However, the mutant embryos were more sensitive to ultraviolet (UV) irradiation. Upon UV irradiation, compared with the wild type embryos, mutant embryos accumulated significantly higher levels of unrepaired DNA damages and apoptotic cells, which led to more severe abnormal development. Transcriptome analysis showed that the p53 signal pathway and apoptosis were enriched in the over upregulated genes in UV-irradiated mutant embryos, suggesting that high levels of unrepaired DNA lesions activated p53 to trigger apoptotic activity in mutant embryos. More interestingly, up to 972 genes in the untreated mutant embryos were differentially expressed, compared with those in the untreated WT. Among these differentially expressed genes (DEGs), 379 genes did not respond to UV irradiation, indicating that Xpc plays a role in addition of DNA damage repair. Our results demonstrate that Xpc is an evolutionally conserved factor in NER repair. Zebrafish xpc−/− mutant also provides a platform to study other functions of Xpc beyond the DNA damage repair. [ABSTRACT FROM AUTHOR]

Polyvinyl Alcohol (PVA) of PVA-3%M, where M stands for NiO, MgO, and Al2O3, has been created. Characterization was done using X-ray diffraction (XRD). This characteristic verified the production of the generated oxide NPs during chemical precipitation in PVA. The PVA-3% M nanoparticles (M=NiO, MgO, and Al2O3) xamined for their optical characteristics. After 60 minutes, the PVA-3% M nanoparticles (M=NiO, MgO, and Al2O3) were subjected to UV light irradiation to examine its effects. The optical properties have been studied in UVA (315-400 nm) area, or long-wave UV, in energy of (3.9-3.1) eV. Time under UV light has an impact on the optical energy gap of PVA-3% M. As a function of the UV exposure time, the optical characteristics of PVA-3% M nanoparticles (M=NiO, MgO, and Al2O3) were evaluated. Calculated optical constants for PVA-3% M (M=NiO, MgO, Al2O3) NPs as-prepared and after UV irradiation illustrate the impact of UV irradiation period. These data demonstrate that a highly forced for medical applications. [ABSTRACT FROM AUTHOR]

In this work, the effects of the solvents, pH, and concentration on the photolysis of CH3I under UV irradiation were investigated. The photolysis of CH3I mainly occurs in the gas phase and is faster in its aqueous solution compared to in its n-hexane and methanol–water solutions. UV irradiation-induced photolysis of CH3I produces I2 and I3− whereas the formation of the latter is affected by the former. In addition, both the pH and concentration of CH3I aqueous solutions affect the formation and transformation of I3− and I2. The results are helpful and referable to understanding the photolysis behavior of CH3I under UV irradiation. [ABSTRACT FROM AUTHOR]

• Degradation analysis of PV module after 20 years of exposure in the field. • A methodology designed for the accelerated UV stress test for different climatic conditions. • A procedure proposed to estimate the UV radiation for different climatic conditions. • Accelerated UV stress testing condition design for Indian climatic condition. One of the significant environmental stress factors for degradation in the PV module is UV irradiation exposure in the field during its operational lifespan. In this work, degradation analysis of 20-years field-operated PV modules have been performed. The defects that occurred in those modules are due to the combined effect of environmental conditions like temperature, humidity, soiling, etc., along with UV irradiation. Based on the literature resources, efforts have been made to analyze the role of UV irradiation on the degradations that happened during 20 years of field operation of the PV modules. Average P max , I sc and V oc degradation are found to be 1.49 %/ year, 0.59 %/year and 0.29 %/year after 20 years of exposure, respectively. The effect of UV irradiation and temperature in indoor conditions has been analyzed for the 20 years of field-exposed PV modules. The effect of browning in the module is also studied in this research work at the cell level. Since the UV irradiation doses mentioned in IEC 61215 are not sufficient as compared to the amount of UV irradiation faced by the PV modules throughout their lifetime, therefore, a procedure is proposed to estimate the UV irradiation doses for different climatic conditions. The UV radiation data for India's climatic zones have been estimated and analyzed, to design accelerated UV stress test conditions using the procedure reported in this paper. The accelerated testing time equivalent for five years of UV irradiations on PV modules in the field is proposed to be around 40 days. [ABSTRACT FROM AUTHOR]

Dyed wood is prone to photoaging when exposed to UV irradiation which decreases its decorative effect and service life. Holocellulose, as the main component of dyed wood, has a photodegradation behavior which is still unclear. To investigate the effect of UV irradiation on chemical structure and microscopic morphology changes of dyed wood holocellulose, Maple birch (Betulacostata Trautv) dyed wood and holocellulose were exposed to UV accelerated aging treatment; the photoresponsivity includes crystallization, chemical structure, thermal stability, and microstructure were studied. Results showed that UV radiation has no significant effect on the lattice structure of dyed wood fibers. The wood crystal zone diffraction 2θ and layer spacing was basically unchanged. With the UV radiation time extension, the relative crystallinity of dyed wood and holocellulose showed a trend of increasing first and then decreasing, but the overall change was not significant. The relative crystallinity change range of the dyed wood was not more than 3%, and the dyed holocellulose was not more than 5%. UV radiation caused the molecular chain chemical bond in the non-crystalline region of dyed holocellulose to break, the fiber underwent photooxidation degradation, and the surface photoetching feature was prominent. Wood fiber morphology was damaged and destroyed, finally leading to the degradation and corrosion of the dyed wood. Studying the photodegradation of holocellulose is helpful to understand the photochromic mechanism of dyed wood, and, further, to improve its weather resistance. [ABSTRACT FROM AUTHOR]

PLA and its blends are the most extensively used materials for various biomedical applications such as scaffolds, implants, and other medical devices. The most extensively used method for tubular scaffold fabrication is by using the extrusion process. However, PLA scaffolds show limitations such as low mechanical strength as compared to metallic scaffolds and inferior bioactivities, limiting their clinical application. Thus, in order to improve the mechanical properties of tubular scaffolds, they were biaxially expanded, wherein the bioactivity can be improved by surface modifications using UV treatment. However, detailed studies are needed to study the effect of UV irradiation on the surface properties of biaxially expanded scaffolds. In this work, tubular scaffolds were fabricated using a novel single-step biaxial expansion process, and the surface properties of the tubular scaffolds after different durations of UV irradiation were evaluated. The results show that changes in the surface wettability of scaffolds were observed after 2 min of UV exposure, and wettability increased with the increased duration of UV exposure. FTIR and XPS results were in conjunction and showed the formation of oxygen-rich functional groups with the increased UV irradiation of the surface. AFM showed increased surface roughness with the increase in UV duration. However, it was observed that scaffold crystallinity first increased and then decreased with the UV exposure. This study provides a new and detailed insight into the surface modification of the PLA scaffolds using UV exposure. [ABSTRACT FROM AUTHOR]

In this study, the yield of gelatin extraction from fish waste was optimized using response surface method. The highest yield was obtained with 0.8% citric acid concentration at 72.95°C for 58 minutes. Then, fish gelatin was modified using ultraviolet radiation to overcome fish gelatin defects including unsuitable rheological properties and low thermo-stability. UV irradiation can create crosslinks via alkyl or phenyl groups of the proteins. The modified sample also showed the highest melting point due to the creation of cross-links and improved emulsification and foaming properties of fish gelatin through structural modification and increased surface hydrophobicity of gelatin. [ABSTRACT FROM AUTHOR]

Vitamin D2 is produced from its precursor ergosterol under the impact of ultraviolet (UV) light which is also commercially carried out to increase vitamin D2 contents in mushrooms ('Novel Food'). However, this process is accompanied by the formation of various isomers that partly co-elute with the target compound and are currently difficult to analyze. For this reason, vitamin D2 and ergosterol were irradiated with the goal to generate and characterize various isomeric photoproducts with three analytical methods. High-performance liquid chromatography with ultraviolet detection (HPLC–UV) was accompanied by using a chiral detector (CD) which was serially linked with the UV detector. Applied for the first time in this research area, HPLC-CD chromatograms provided complementary information which was crucial for the identification of several co-elutions that would have been overlooked without this approach. Additional information was derived from gas chromatography with mass spectrometry analysis. Diagnostic fragment ions in the GC/MS spectra allowed to distinguish four classes of tri- (n = 2), tetra-, and pentacyclic isomer groups. Despite several drawbacks of each of the applied methods, the shared evaluation allowed to characterize more than ten isomeric photoproducts of vitamin D2 including previtamin D2, lumisterol2, tachysterol2,trans-vitamin D2 isomers, and two pentacyclic isomers (suprasterols2 I and II), which were isolated and characterized by proton magnetic resonance spectroscopy (1H NMR). [ABSTRACT FROM AUTHOR]

This article reports the green synthesis of zinc oxide nanoparticles (ZnO NPs) by using the aqueous leaf extract of Trema orientalis (L). The ZnO NPs were synthesised by using zinc nitrate hexahydrate acts as the precursor and leaf extract acts as the reducing and capping agent. The synthesis of ZnO NPs was confirmed by the powder X-ray diffraction (XRD) analysis and the average crystalline size was calculated by Scherrer's formula (24 nm) and as well as Williamson-Hall (W-H) equation (26 nm). The Dynamic Light Scattering (DLS) analysis showed the stability and particle size of approximately 65–67 nm of the synthesised ZnO NPs. The Fourier Transform Infrared Spectroscopy (FTIR) analysis confirmed the presence of various functional groups in the synthesised NPs. The UV absorption wavelength is observed at 370 nm, and the calculated direct band gap was found to be 3.13 eV. The surface morphology, the crystalline shape of the synthesised ZnO NPs was determined by using Scanning Electron Microscopy (SEM). The effectiveness of the ZnO NPs on photocatalytic degradation of zoxamide, a benzamide class of fungicide was tested under UV irradiation (λ max ≥ 250 nm). The calculated half-lives of photodegradation of zoxamide in acetonitrile/water solvent system were found to be in the range of 4.09 − 10.46 h. Moreover, the effect of pH, the initial concentration of zoxamide and photocatalyst ZnO NPs dosage were investigated. The experimental kinetic data followed the pseudo-first-order model. The reaction rate constant (kobs) was decreased from 0.1695 to 0.1511 h−1 with increasing initial zoxamide concentration from 120 to 260 mg/L, respectively. Langmuir–Hinshelwood (L–H) kinetic model was proposed for the rate equation of the zoxamide degradation in presence of ZnO NPs under UV irradiation. [ABSTRACT FROM AUTHOR]

Storage in aqueous solution or ultraviolet (UV) irradiation can retain or regain the hydrophilicity of titanium implant surface. In this study, 3 types of commercial titanium implants were used: ZBL (ZDI Bone Level), CEL (C-tech Esthetic Line), and modSLA (Straumann SLActive). ZBL and CEL implants were treated with UV irradiation for 4 hours. Surface characterization of the 4 groups (ZBL, ZBL-UV, CEL-UV, and modSLA) was evaluated by scanning electron microscopy and contact angle measurements. The in vivo bone response was evaluated by removal torque (RTQ) tests and histomorphometric analysis at 3, 6, and 12 weeks postimplantation. A total of 144 implants and 36 rabbits were used for experiments according to a previously established randomization sequence. The ZBL-UV, CEL-UV, and modSLA groups were hydrophilic, and nanostructures were observed on the modSLA implant surface. ModSLA achieved better RTQ value than ZBL at 12 weeks (P <.05). For histomorphometric analysis, ZBL-UV and CEL-UV implants showed higher bone area values in the cancellous bone zone at 6 weeks than did modSLA and ZBL implants (P <.05). In the cortical bone zone, all groups showed comparable bone-to-implant contact at all healing time points (P >.05). Both storage in saline and UV irradiation could retain or provoke hydrophilic surfaces and improve osseointegration. Compared with storage in saline, UV irradiation displayed slight advantages in promoting new bone formation in cancellous bone zone at an early stage. [ABSTRACT FROM AUTHOR]

Cryptosporidium, a protozoan parasite, in wastewater presents a major public health concern for water safety. However, bactericidal efficiencies of conventional disinfection methods towards Cryptosporidium oocysts are still hampered owing to the presence of their thick outer wall. In this study, we present a novel UV inactivation process where the efficiency has been significantly enhanced by addition of a trypsin pretreatment stage. Notably, inactivation (log-reduction) of oocysts was noted to be 73.75–294.72% higher than that obtained by UV irradiation alone, under identical conditions. Experimental observations and supporting mechanistic analyses suggest that trypsin led to cleavage of the protein layers on the oocyst wall, facilitating penetration of UV radiation into the oocysts leading to degradation of their genomic DNA (gDNA). The dissociative effect of trypsin on the oocyst wall was indicated by the fact that 64.50% of oocysts displayed early apoptosis after trypsinization. Imaging by scanning electron microscopy indicated that this combined treatment led to substantial disruption of the oocyst coat, deforming their shape. This resulted in the release of cellular proteins and gDNA, their concentrations in bulk solution increasing by 1.22–8.60 times. As UV irradiation time was prolonged, gDNA was degraded into smaller fragments with lower molecular masses. Both laddering and diffuse smear patterns in gel analysis indicated significantly detrimental effects on gDNA and viability of oocysts. Overall, this study demonstrated enhancement of UV inactivation of Cryptosporidium oocysts by trypsin and explored the underlying mechanisms for the process. [ABSTRACT FROM AUTHOR]

The study investigates the effect of UV irradiation on different native and exotic wood species which is an open subject of research. Thirteen native wood species and ten exotic wood species, totally twenty-three wood species, all important for wood industry in Turkey, were subjected to UVA-340nm irradiation with a constant irradiance of 0.89 W/m2/nm and a temperature of 60 °C for 2, 4, 8, 16, 24, 48, 72, 96, 120, 144, 168, 252 and 336 h to determine the critical degradation time for the wood species. A short exposure time (from 2h to 48h) was especially studied since the previous studies reported that important and rapid changes occurred within the initial exposure periods. The effect of UV irradiation on wood surfaces was investigated by color, surface roughness, and FTIR-ATR measurements. The results proved that UV radiation caused a rapid color change for extractive-rich wood species at the initial period of exposure (16h–48h) which decreases upon prolonged exposure. The overall color change and surface roughness were higher for native wood species in a long exposure period than for exotic ones. Elm, oak, plane, walnut, acacia and linden as native wood species, iroko, tiama, acajou, okoume, garapa, sapelli, dibetou and teak as exotic wood species were found to be more resistant to color changes in prolonged irradiation periods, probably due to content of their components especially extractives and lignin. Similar to greater color change found within the beginning of the irradiation period (16h–48h), the first 8h–24h seemed to cause a greater increase in roughness for exotic species and 16h–24h for native wood species probably due to the changes in surface chemistry. Acacia, elm, cherry, beech, tiama, teak and okoume had the highest RI whilst S. pine, ash, poplar, plane, sapelli, limba and iroko had the lowest RI among the wood species. FTIR–ATR analysis demonstrated that UV light ended up with photodegradation of lignin and photooxidation of hemicelluloses which leads carbonyl-containing chromophores, even after short-time exposures (8h–24h). • Twenty-three wood species were exposed to UV irradiation from 2h to 336h. • The first 8–48 h of exposure period was found to be important for wood properties. • Color and roughness changes were higher for native wood species than for exotic ones. • Iroko, elm, tiama, acajou and okoume were found to be more resistant to color changes. • Significant changes occurred in lignin and hemicellulose component on irradiated surfaces. [ABSTRACT FROM AUTHOR]

Polymethylmethacrylate (PMMA) is commonly applied to microfluidic devices due to its excellent biocompatibility, high optical transparency, and suitability for mass production. Recently, various surface treatment methods have been reported to improve the wettability of polymers, which is directly related to adhesion. In this research, the effect of a UV irradiation technique and an IPA rinsing technique as surface treatments for PMMA is investigated regarding the water contact angle of the PMMA surface. PMMA sheets that were 1.62 mm thick and commercially available were exposed to UV light with four different exposure times. Significant decreases in the water contact angle were observed after exposure to UV light, and the lowered contact angles due to the UV irradiation increased over time. According to the measurement, the water contact angle is a function of UV exposure dose as well as storage time after UV exposure. We examined the effect of a IPA rinsing process after UV irradiation and observed an increase in the water contact angle. [ABSTRACT FROM AUTHOR]

The aim of the paper consists in assessing the protection of fir wood samples against UV degradation by using polyacrylates and titanium dioxide as absorber. The irradiation was achieved for 648 hours, considered as about 2 years of weathering. Colorimetric, water absorption, and mechanical investigations were performed on samples before and after irradiation. The structural changes were evidenced by FTIR spectroscopy. Small changes in color for coated wood samples are observed after maximum 648 h of UV treatment, with the best results obtained for the specimen covered with Paraloid B72-TiO2. Higher compressive strengths were observed for the polymer-TiO2 coatings, in correlation with a smaller water absorption capacity of the studied samples. FTIR revealed shifted peaks with increased intensities as proof of structural changes produced by irradiation of lignin and polyacrylates. The results highlight that Paraloid B72 and Paraloid B67 mixed with TiO2 can be used as efficient UV protective coatings for fir wood. [ABSTRACT FROM AUTHOR]

In order to enhancement the antimicrobial properties and the thermal stability of the cotton fabrics for outdoor uses, they were coated with formulations of room-temperature vulcanizing silicone rubber (RTVSR)/synthesized zinc oxide nanoparticles (ZnO NPs). The coated fabrics were adjusted to different doses of ultraviolet (UV) irradiation, which act as a crosslinking factor to the silicone rubber, rather than as a photocatalytic agent for enhancing the antimicrobial activity of the ZnO NPs. The synthesized ZnO NPs were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM); meanwhile, its impurity was examined using energy dispersive X-ray (EDS) analysis. The thermal stability and surface morphology of the coated fabrics were characterized by thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The results showed that the mechanical strength (MPa) of the coated fabrics was enhanced by ∼11% after UV irradiation for 120 min, accompanied by decrease in its swelling and solubility by ∼10 and 20%, respectively, as a result of UV crosslinking effect upon RTVSR. Meanwhile, the antimicrobial activity of the coated fabrics was enhanced by ∼50%, as a result of the photocatalytic effect of UV irradiation (120 min), at the constant percentage of 3% (ZnO NPs) in the coating formulations. [ABSTRACT FROM AUTHOR]

Summary: The study investigated the properties and storage stability of Japanese Spanish mackerel (Scomberomorus niphonius) surimi gel exposed to ultraviolet irradiation for 0.5, 1, 2 and 3 h (UV0.5, UV1, UV2, UV3) before thermal treatment. The results showed that all UV‐irradiated surimi gels exhibited compact microstructure along with increased gel strength and water‐holding capacity than control. Investigations on chemical properties of myofibrillar protein (MP) from surimi showed that tryptophan fluorescence intensity declined while bromophenol blue‐binding capability increased after UV irradiation. Sulfhydryl content in MP of UV2 and UV3 decreased while their carbonyl content increased. Electrophoresis analysis indicated that myosin heavy chain of UV2 was most attenuated. Storage test showed that UV2 maintained the highest gel strength during chilled‐storage and its total viable count was below 5 log10CFU•g−1 after 18 days. Therefore, UV irradiation might be applied to improve surimi gel properties and extend shelf life. [ABSTRACT FROM AUTHOR]

Polycarbonate (PC)-ZnO films with different percentages of ZnO were prepared by a solution stirring technique and subjected to ultraviolet (UV; λ = 254 nm) irradiation. Structural parameters of the samples and the effects of UV irradiation on the surface properties of the PC and PC-ZnO nanocomposites were evaluated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), water contact angle (WCA) measurements, and a Vickers microhardness (HV) tester. The XRD patterns of the nanocomposite films were found to show an increase in crystallinity with the increasing ZnO nanoparticles percentage. The WCA was found to be reduced from 90° to 17° after 15 h of UV irradiation, which could be ascribed to the oxidation of the surface of the samples during the irradiation and exposure of the ZnO nanoparticles, a result that is also supported by the obtained XPS data. The microhardness value of the PC-ZnO films including 30 wt.% ZnO enhanced considerably after UV radiation, which can also be attributed to the exposition of the ZnO nanoparticles after photodegradation of the PC superficial layer of the nanocomposite films. [ABSTRACT FROM AUTHOR]

Waterborne pathogens are a leading cause of disease and death worldwide. Ultraviolet (UV) irradiation is an effective method of drinking water treatment through the destruction of cells at the molecular level. Throughput capacity per unit volume of the UV unit is a major driver of the treatment process. In this study, we developed a microscale-based reactor in combination with UV radiation to determine the inactivation efficacy of bacteriophage MS2 and Escherichia coli. Using the microscale-based reactor, we achieved inactivation of more than 7 log colony forming units per mL of E. coli by 8 s and removal of more than 7.5 log plaque forming units per mL of bacteriophage MS2 by 8 min residence times. These values meet and surpass the standards set by the U.S.-Environmental Protection Agency and the World Health Organization for drinking water treatment technologies. Results from mathematical modeling suggest that the best fit model is obtained when we assume that more than a single photon directly damages E. coli cells and allows a transitional damaged state or further inactivation by additional photons. The successful application of a point-of-use UV water disinfection device to inactivate pathogens creates new opportunities for household and commercial water treatment globally. [ABSTRACT FROM AUTHOR]

High crystallization and conductivity are always required for inorganic carrier transport materials for cheap and high‐performance inverted perovskite solar cells (PSCs). High temperature and external doping are inevitably introduced and thus greatly hamper the applications of inorganic materials for mass production of flexible and tandem devices. Here, an amorphous and dopant‐free inorganic material, Ni3+‐rich NiOx, is reported to be fabricated by a novel UV irradiation strategy, which is facile, easily scaled‐up, and energy‐saving because all the processing temperatures are below 82 ℃. The as‐prepared NiOx film shows highly improved conductivity and hole extraction ability. The rigid and flexible PSCs present the champion efficiencies of 22.45% and 19.7%, respectively. This work fills the gap of preparing metal oxide films at the temperature below 150 °C for inverted PSCs with the high efficiency of >22%. More importantly, this work upgrades the substantial understanding about inorganic materials to function well as efficient carrier transport layers without external doping and high crystallization. [ABSTRACT FROM AUTHOR]

The effect of temperature and UV irradiation on the corrosion behavior of 304 stainless steel exposed to a simulated marine atmosphere was studied. The corroded samples were analyzed in detail through potentiodynamic polarization, in situ electrochemical impedance spectroscopy, Mott–Schottky measurements, scanning electron microscopy, and X‐ray photoelectron spectroscopy. The results showed that the corrosion rate of 304 SS was significantly inhibited by UV irradiation, and the inhibition effect increased at a higher temperature. The UV irradiation not only changed the corrosion products morphologies formed on the 304 SS surface but also the relative content of the corrosion products was changed. In particular, UV irradiation can promote the formation of Cr2O3 in corrosion products, especially at a higher temperature, thus improving the corrosion resistance of 304 SS. [ABSTRACT FROM AUTHOR]

Ultraviolet (UV) radiation and corrosion can be coupled in non-trivial ways and such coupling is of critical importance for the performance of materials in extreme environments. However, the confluence of these phenomena and their collective impact remains underexplored. This study bridges this knowledge gap by presenting a thorough investigation of Zr alloys exposed to corrosive high-temperature water under in-situ UV irradiation. We found that initial UV exposure significantly accelerates corrosion and induces distinct changes in the microstructure of ZrO 2 oxides. Over time, we observed the formation of Fe 3 O 4 particles on the ZrO 2 surface due to photo-dissolution of zirconia and photo-deposition of iron oxide magnetite. The emergence of Fe 3 O 4 particles could enhance the corrosion resistance of the Zr alloy substrate. Furthermore, our results indicate that UV irradiation modulates the density and distribution of nanopores within the oxide layer by influencing oxygen speciation and the dynamics of oxide growth. These insights advance our understanding of the complex interplay between UV irradiation and high-temperature water corrosion. [Display omitted] [ABSTRACT FROM AUTHOR]