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Currently, wound dressing technology is of significant interest in order to avoid undesired effects when burns or skin wounds are treated, especially their risk for microbial contamination and subsequent infection. Silver nanoparticles (AgNPs) have claimed importance as antimicrobial agents. For these reasons, a comparative study of different methods to synthesize electrospun polymeric fibers loaded with AgNPs (Ag+/PCLPVP) such as direct blending, ultraviolet irradiation, thermal treatment, and silver mirror reaction methods were done. The morphology and size of the fibers were investigated using the SEM, where the loading of the AgNPs in the fibers was measured with EDS analysis. FTIR, Raman spectroscopy, XRD, and TGA analysis were applied to measure the physicochemical properties of the fibers. DLS study allowed us to measure the size and surface charge of the obtained materials. The antimicrobial efficiency was carried out against Staphylococcus aureus and Escherichia coli bacteria for 24 h. Cytotoxicity was evaluated with the MTT assay using HFF1 cells. The results showed that the method with the best antimicrobial effect in both bacteria is the UV irradiation conducted before the electrospinning process. The UV radiation method also promotes good distribution efficiency, the physicochemical properties obtained were desirable for wound dressings, and the particle size within nanoparticle interval (~17 nm). Therefore, the most promising method for the preparation of Ag+/PCLPVPbased wound dressings was UV irradiation. [ABSTRACT FROM AUTHOR]

Cr(III)-organic complexes are stably presented in tanning, electroplating, and other industrial wastewaters, and their safe and efficient removal remains a current challenge. Available oxidation processes can remove Cr(III) complexes but readily result in highly toxic Cr(VI) accumulation. Herein, negligible Cr(VI) accumulation was achieved during photo-oxidation of Cr(III) complexes using a simple strategy of decreasing dissolved oxygen (DO). At the DO concentration of 5.0 mg·L−1 or less, the in-process formation of intermediate Cr(VI) was totally abated by in situ formed reductive species, and total Cr was reduced from 9.0–11.0 mg·L−1 to below 1.0 mg·L−1. A complete curtailment of Cr(VI) was observed after 30–60 min at pH 6.0–9.0. Increasing Cr(III)-EDTA concentration and decreasing pH value facilitated the in situ reduction of intermediate Cr(VI). Based on the identification of intermediates and additional Cr(II) and quenching experiments, the possible key species involved in intermediate Cr(VI) reduction were the photogenerated Cr(II) and some C-centered radicals from Cr(III)-EDTA decomplexation, and the possible mechanisms of Cr(III)-EDTA decomplexation and intermediate Cr(VI) reduction were thus proposed. The process also showed efficient treatment on other Cr(III) complexes (citrate, oxalate, and tartrate) and realistic Cr(III) complexed wastewater. This study would provide an insignificant Cr(VI)-accumulated alternative for efficient and safe removal of Cr(III) complexes from contaminated water. [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]

Smart surfaces with externally controlled wettability patterns are ubiquitous building blocks for micro-/nanofluidic and lab-on-chip devices, among others. We develop hierarchical surfaces of ZnO nanorods grown on laser-microstructured silicon with reversible photo-induced and heat-induced wettability. The as-prepared surfaces are superhydrophilic, with very low water contact angles (~ 10°), and transition to a wetting state with high water contact angles (~ 150°) when annealed in vacuum. As the annealing temperature increases to 400 °C, the surfaces become completely water-repellent. Even though the annealed surfaces present high water contact angles, at the same time, they are very adhesive for water droplets, which do not roll off even when tilted at 90° or 180o (rose-petal effect), unlike standard hydrophobic surfaces which typically combine high water contact angles with low roll-off angles. The surfaces return to the superhydrophilic state when irradiated with UV light, which indicates a reversible wettability with external stimuli. Based on this transition, we demonstrate local modification of the wetting state of the surfaces by UV irradiation through a mask, which results in directed liquid motion, useful for microfluidic applications. The high contact angles obtained in this work are usually obtained only after chemical modification of the ZnO surface with organic coatings, which was not necessary for the hierarchical surfaces developed here, reducing the cost and processing steps of the fabrication route. These rose-petal surfaces can be used as "mechanical hands" in several applications, such as no-loss transport of small liquid volumes, precision coatings, spectroscopy, and others. Furthermore, the completely water-repellent surfaces, rarely reported elsewhere, may find important applications in frictionless liquid transport for microfluidic and other devices. [ABSTRACT FROM AUTHOR]

Sunlight is essential for humans. However, sunlight can be the source of several disadvantageous effects and illnesses, e.g., skin aging, sunburn, and skin cancer. Textiles with functional protective effects can counteract these problems. In the current research, knitted fabrics were produced from Lyocell yarns spin-doped with the inorganic UV absorber titanium dioxide TiO2. Lyocell yarns without TiO2 were used as reference materials. The produced knitted fabrics were dyed with different dyestuffs to improve the protective properties against UV light and infrared light. The protective properties are determined by optical spectroscopy in an arrangement of diffusive transmission. With the two dyestuffs Drimaren Yellow HF-CD and Solophenyl Bordeaux 3BLE, dyes were determined which complete UV protection and additionally reduce transmission in the near-IR range (700 nm to 1000 nm). TiO2 in the fibers enhanced this effect. In the UV range (280 nm to 400 nm), the transmission was almost zero with both dyes. Overall, the Lyocell samples containing TiO2 exhibit less sensitivity to abrasion and a UV protective effect after washing can be still determined. The weight loss after the abrasion test for these samples is quite low with only around 8.5 wt-% (10,000 rubbing cycles in the Martindale device). It is concluded that the right choice of dye can improve the protective effect of textiles against various types of radiation. Lyocell fiber-based textiles are suitable for the production of summer clothing due to their good moisture management. Compared to other radiation protective materials based on coating application, the presented solution is advantageous, because the textile properties of the realized products are still present. For this, a direct transfer to clothing application and use in apparel is easily possible. This study can be seen as the first proof-of-concept for the future development of light-protective clothing products. [ABSTRACT FROM AUTHOR]

Curcuma rhizome is reported to have a high total phenolics that could act as reducing agents for metals to nanoparticles. Rhizomes of five curcuma species were selected as bioreductors, namely white turmeric (Curcuma zedoaria), black turmeric (C. aeruginosa), fingerroot (C. rotunda), temu giring (C. heyneana), and mango ginger (C. amada). The research was designed to select the reductor from five Curcuma rhizomes mentioned above for silver nanoparticles synthesis, optimizing the synthesis condition, and evaluating its potential as a sunscreen agent. Silver nanoparticles (AgNPs) were synthesized by mixing the extracts with AgNO3 and irradiating the solution under a 366 nm UV lamp at certain times and pHs. Based on the spectra, the highest absorbance of silver nanoparticles was detected on the temu kunci extract. The optimum conditions for silver nanoparticle-temu kunci (AgNPs-TK) were determined using a Box-Behnken Design and Minitab. Statistical results showed that 0.13 g of silver nitrate irradiated for 162.7 min at pH 11.34 was the optimum condition for AgNPs synthesis. The synthesized AgNPs were characterized by PSA/DLS, XRD, and TEM. The TEM analysis confirmed that silver particles are spherical. The size of the AgNPs produced based on TEM analysis is 5-50 nm. Sunlight inhibition activity, determined spectrophotometrically, indicated that the sun protection factor of AgNPs-TK is categorized as a minimum protection in concentration of 25 ppm. [ABSTRACT FROM AUTHOR]

The photo‐oxidation of poly(diethylene glycol terephthalate) (PDEGT) under accelerated aging conditions has been investigated. A weatherometer was used to expose samples to simulated sunlight under air, replicating outdoor exposure. Irradiations were also performed under air using UV lamps of wavelengths centred on 302 and 365 nm. After exposure, the extent of degradation was determined using attenuated total reflectance Fourier transform infrared spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy and UV–visible spectroscopy. Results show that in general PDEGT degrades to a greater extent than the closely‐related polymer poly(ethylene terephthalate) due to the susceptibility of the ether linkage. Although the diethylene glycol sequences are not themselves photoactive over this wavelength range and are not acting as photochemical weak links they do serve as additional sites for secondary free radical chemistry. [ABSTRACT FROM AUTHOR]

Mulching technology has created a major problem of agricultural plastic pollution. This is because the mulch is severely degraded by UV (ultraviolet) irradiation and the mechanical properties deteriorate, which makes mechanical recycling or manual recycling difficult. This study was conducted on m-LLDPE (metallocene linear low-density polyethylene) mulch films. The difference in mechanical properties of specimens in the TD (transverse direction) and PD (parallel direction) was investigated, and the changes in the mechanical properties after UV irradiation were compared. Finally, an initial mulch mechanical property evaluation model was developed to adapt to different recovery machines and crop agronomic requirements. The results suggest that the mechanical properties of m-LLDPE mulch films were strongly influenced by the film thickness, and also showed directional differences in tensile and tear properties. After UV irradiation, the mechanical properties of the specimens were enhanced after a short period of time, but the overall trend was a non-linear decay which gradually slowed down with time. [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]

A new system to remove natural organic matter from water can considerably decrease the risk of hazardous by-product formation was designed. In this study, the settling process in water treatment plants was upgraded using Titanium dioxide nanoparticles coated on the inner side of the settling tank using the dip-coating method to eliminate total organic carbon. The FESEM and EDX analysis of the immobilized Titanium dioxide layer indicated homogenous dispersion of Titanium dioxide on Sekurit glass. Furthermore, the Raman and FTIR spectrum of the modified surface represented the specific Raman bands and surface functional groups of Titanium dioxide, respectively. The experiments were conducted under different UV irradiation (8, 16, and 24W) to evaluate the photocatalytic activity of Titanium dioxide to enhance the coagulation-flocculation process. The experiment carried out using 24 W UVa lamps for 180 min was able to remove 95% of turbidity and total organic carbon. The conventional method removed just about 33% of total organic carbon in the same treatment process showing inefficiency to achieve drinking water standards. However, the treated water in the enhanced photocatalytic system achieved drinking water standard according to EPA(total organic carbon < 2 mg/L). The enhanced photocatalytic degradation followed the pseudo-first-order reaction kinetics with a correlation coefficient of (R2 > 0.99). Performing experiments in different settling cycles demonstrated good stability of Titanium dioxide coated layer, and the removal efficiency reduced 6% after five cycles, establishing the proposed method is practical and also much more efficient. [ABSTRACT FROM AUTHOR]

Type I collagen is the most common extracellular matrix protein in the human body that provides the basis of tissue structure and regulates cellular functions. In the process of vital activity, the components of the extracellular matrix, in particular collagen, are exposed to ultraviolet radiation. The purpose of this work was to study the effect of ultraviolet irradiation on the stability and structure of collagen fibrils. It has been shown that ultraviolet irradiation had a stabilizing effect on a collagen gel at a concentration of 0.5 mg/mL. The analysis of the diameters of collagen fibrils after ultraviolet irradiation by scanning electron microscopy revealed no change in their size. The area of spreading of cells cultured on collagen fibrils after ultraviolet irradiation was higher compared to the area of cells cultured on collagen fibrils without treatment. It was shown by IR-Fourier spectroscopy that ultraviolet irradiation caused a shift of the amide A band of collagen to a lower frequency region, which indicated a change in the structural order of collagen. [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]

Antibiotic resistance genes can be spread via gene horizontal transfer (GHT). Chlorination and UV irradiation are common disinfection methods used in wastewater treatment plants before the discharge of treated wastewater. This study aimed to elucidate the effects of disinfection on the transformation of naked DNA in the aquatic environment. The pUC19 plasmid possessing ampicillin-resistant beta-lactamase and subjected to different dosages of chlorine or UV irradiation was used for transformation in Escherichia coli to estimate the transformation efficiency and GHT in the environment after disinfection. The results showed that doses > 0.5 mg-Cl2/L can effectively decrease transformation efficiency (1.21 to 8.83-log10) based on pUC19 as the positive control. UV irradiation can decrease the efficiency (2.37 to 3.39-log10) following 10–60 min of treatment. PCR and qPCR detection have limitations for determining transformation efficiency because they provide approximate estimates damaged DNAs. Overall, these results indicate that proper disinfection management using chlorine and/or UV for treated wastewater before discharge from wastewater treatment plants can prevent the spread of antibiotic resistant bacteria and genes, by decreasing the efficiency of naturally occurring bacterial transformations in wastewater treatment plants. [ABSTRACT FROM AUTHOR]

In current study the photocatalyst ZnO was prepared by complexation of zinc acetate with sodium diethyl dithiocarbamate trihydrate, and calcined at 750 °C. The ZnO nanoparticles were characterized by DLS, Zeta potential, SEM, EDX and FTIR. The ZnO nanoparticles (NPs) were applied for photocatalytic degradation of Eriochrome black-T (EBT) dye by UV, visible and mercury light irradiation sources. The experimental conditions were optimized by univariate and multivariate techniques, and it was revealed that degradation of dye by ZnO NPs surface was dependent on source of light and pH of dye solution. The degradation of EBT dye at pH 11 showed highest degradation rate 99.64% with UV light. The ZnO was calcined at 450, 600, 750 and 900 °C, but the calcination temperature 750 °C showed better degradation rate for EBT. The highest degradation was found at 15 mg dose and 5 ppm concentration. The effects of Na+, Ca2+, K+, Mg2+ on the degradation, were studied and these salts had no effect on degradation rate. The degradation obeyed pseudo second order kinetics model as compared to pseudo first and zero order models and Langmuir isotherm model fitted more as compare to other models. The effects of variables were examined by factorial design of 18 experiments by cantered Draper-Lin small composite model. The degradation of EBT dye in real samples collected from River Indus, tape water and domestic wastewater and spiked with 20 μg/mL, indicated that the dye degraded upto 82–86% with relative standard deviations (RSD) within 2% (n = 3). [ABSTRACT FROM AUTHOR]

Quinones are frequently used as derivatization reagents in HPLC analysis to improve detection sensitivity. In the present study, a simple, sensitive, and selective chemiluminescence (CL) derivatization strategy for biogenic amines, prior to their HPLC-CL analysis, was developed. The novel CL derivatization strategy was established based on using anthraquinone-2-carbonyl chloride as derivatizing agent for amines and then using the unique property of the quinones' moiety to generate reactive oxygen species (ROS) in response to UV irradiation. Typical amines such as tryptamine and phenethylamine were derivatized with anthraquinone-2-carbonyl chloride and then injected into an HPLC system equipped with an online photoreactor. The anthraquinone-tagged amines are separated and then UV-irradiated when they pass through a photoreactor to generate ROS from the quinone moiety of the derivative. Tryptamine and phenethylamine can be determined by measuring the chemiluminescence intensity produced by the reaction of the generated ROS with luminol. The chemiluminescence disappears when the photoreactor is turned off, suggesting that ROS are no longer generated from the quinone moiety in the absence of UV irradiation. This result indicates that the generation of ROS could be controlled by turning the photoreactor on and off. Under the optimized conditions, the limits of detection for tryptamine and phenethylamine were 124 and 84 nM, respectively. The developed method is successfully applied to determine the concentrations of tryptamine and phenethylamine in wine samples. [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]

One of the most important factor that affects the efficient using of baculoviruses as a biopesticide is their sensitivity to UV irradiation. In this study, a photolyase gene (phr) of 1.4 kbp DNA fragment was cloned and characterized from Spodoptera littoralis granulovirus, an Egyptian isolate (SpliGV-EG1). A sequence of 466 amino acid were deduced when the gene was completely sequenced with a predicted molecular mass of ~ 55 kDa. Transcriptional regulation analyses revealed that phr transcripts were detected early at 6-h post-infection (hpi) and remained detectable until 72 hpi, suggesting their transcriptional regulation from a putative early promoter motif. An approximately ~ 55 kDa protein fragment was expressed from phr-induced bacterial culture and detected by SDS-PAGE and western blotting. In addition, direct exposure to UV irradiation resulted in a twofold decrease in SpliGV-EG1 occlusion bodies activation compared with Spodoptera littoralis nucleopolyhedrovirus (SpliNPV) occlusion bodies which decreased with about 129-fold after exposure to UV irradiation based on median lethal concentration value (LC50). The obtained results suggested that the presence of photolyase gene possibly alters the inactivation of SpliGV-EG1-occluded bodies by UV irradiation. These results support the role and application of the photolyase protein to improve the damaged DNA repair mechanism as well as resistance of SpliGV to UV light inactivation. [ABSTRACT FROM AUTHOR]

Current study deals with an agriculture waste paddy straw (PS) incorporated with chitosan (CS) to prepare photocatalytic paddy straw chitosan nanocomposite (PS-CSNC) with cross-linking agent sodium tripolyphosphate was investigated and catalysis-based photocatalytic adsorptions of Rhodamine B (RhB) and Malachite green (MG) in aqueous solution under UV irradiation were also examined. Moreover, this study examined that the factors influence the adsorption process, such as catalyst concentration, pH and temperature, using kinetic models. Additionally, the composite characterization was achieved by several analysis, such as UV–visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction analysis, thermogravimetry/differential thermal analysis and field effect scanning electron microscopy. The study shown that the optimized concentration of PS-CSNC catalyst (3.0 g L−1), below neutral pH (6.5) of the solution and temperature 60 °C achieved excellent removal of both dyes. Initial sorption process involved the removal mechanism of both RhB and MG followed by photocatalytic adsorption. The process of adsorption was well adapted with pseudo second-order kinetics. Overall results suggested that chitosan-based agriculture waste paddy straw nanocomposite could be an eco-friendly and cost-effective bio-adsorbent for removal of RhB and MG in wastewater treatment. [ABSTRACT FROM AUTHOR]

Abstract Intense ultraviolet (UV) exposure can cause phototoxic reactions, such as skin inflammation, resulting in injury. UV is a direct cause of DNA damage, but the mechanisms underlying transcriptional regulation within cells after DNA damage are unclear. The bioinformatics analysis of transcriptome sequencing data from UV‐irradiated and non‐UV‐irradiated skin showed that transcription‐related proteins, such as HSF4 and COIL, mediate cellular response to UV irradiation. HSF4 and COIL can form a complex under UV irradiation, and the preference for binding target genes changed because of the presence of a large number of R‐loops in cells under UV irradiation and the ability of COIL to recognize R‐loops. The regulation of target genes was altered by the HSF4–COIL complex, and the expression of inflammation and ageing‐related genes, such as Atg7, Tfpi, and Lims1, was enhanced. A drug screen was performed for the recognition sites of COIL and R‐loop. N6‐(2‐hydroxyethyl)‐adenosine can competitively bind COIL and inhibit the binding of COIL to the R‐loop. Thus, the activation of downstream inflammation‐related genes and inflammatory skin injury was inhibited.

Ammonia (NH3), as main industrial gas emissions, are extremely harmful to the human beings. So the detection of NH3 concentrations in special environments at room temperature (25 °C) is essential. Herein, the composite MXene Ti3C2Tx-TiO2-CuO was successfully prepared by one-step in-situ oxidation method using Cu(NO3)2·6H2O as a precursor. The morphology of Ti3C2Tx-TiO2-CuO shows layered accordion-like structure. Ti3C2Tx-TiO2-CuO sensor exhibits improved NH3 gas sensing response of 56.9 toward 100 ppm NH3 at room temperature under ultraviolet (UV) light exposure, which is 89.8 % higher than that of pristine Ti3C2Tx material. The improved gas sensing performance is attributed to the irradiation of UV light, the retention of Ti3C2Tx layered structure and the construction of TiO2-CuO heterojunction. Further, the possible gas sensing mechanism of the material was proposed and discussed.

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.

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.

Introduction: Membrane fouling has been reported to be one of the bottlenecks of membrane technologies for wastewater treatment. To mitigate its negative impacts, we fabricated polysulfone membrane (PSf) composites made of silica (SiO2) and graphene oxide (GO) nanoparticles that modified with ultraviolet (UV)-assisted polyvinyl alcohol layer on the membrane surface.Methods: The membrane composite was synthesized using non-solvent induced phase separation (NIPS) method. The membrane was further treated by UV irradiation and cross-linked with PVA coating to cope with the fouling problem. The modified membrane was applied for industrial rubber wastewater decontamination.Results: The UV irradiation and cross-linked PVA coating to the PSf/GO-SiO2 membrane improved the pseudo-steady state permeate flux by 60.15% from 20.05 to 50.32 L/m2hr and maintained the permeate flux up to 82.33%. About 85% of total dissolved solids (TDS), 81% of chemical oxygen demand (COD), and 84% of ammonia compound (NH3) with initial concentrations of 335.76, 242.55, 175.19 mg/L, respectively, could be removed after 8 h of membrane treatment. The modified membrane also exhibited an excellent flux recovery ratio of up to 83%.Discussion: The modified membrane changed the fouling mechanism from pore blockage to cake filtration, which signifies the capability of the membrane to tackle severe fouling tendency. The cross-linked UV/PVA coating reduced fouling formation by reducing the adsorptive interactions between the foulant molecules and the membrane surface by enhancing membrane surface hydrophilicity. This implies that incorporating GO/SiO2 nanoparticles with UV irradiation and PVA coating substantially enhanced the physicochemical properties of the PSf membrane.

In this study, we evaluated the photostability of a cocrystal of naproxen (NPX) and nicotinamide (NA) for the development of the photostabilization strategy. NPX photodegradation during ultraviolet-light (UV) irradiation was estimated by high-performance liquid chromatography (HPLC). The photostability of a NPX-NA cocrystal was less than NPX in the solid-state. Furthermore, NPX was photodegraded faster in the presence of NA at a higher concentration when the NPX-NA mixtures were UV-irradiated. The values of residual amounts of NPX in UV-irradiated NPX-NA cocrystal and mixture were 76.60 ± 3.85% and 70.06 ± 4.09%, respectively, which were significantly lower compared with that of UV-irradiated NPX powder (83.57 ± 2.15%). However, in the case that the effect of NA in the suspension of NPX was investigated, NA had no effect on NPX photodegradation. Residual amounts of NPX in UV-irradiated suspensions of NPX and NPX-NA cocrystal were comparable (33.13 ± 6.02% and 30.22 ± 2.09%, respectively). These results suggested that NA might promote NPX photodegradation only in the solid-state on account of that NA molecule could deliver the excitation energy to NPX molecule. This is the first study focused on the photochemical behavior of NPX-NA cocrystal and mixture and suggests that the presence of NA might induce the change of photostability of NPX in the powder form.

The overuse of disinfection during the COVID-19 pandemic leads to an emerging "health versus environment" dilemma that humans have to face. Irresponsible and unnecessary disinfection should be avoided, while comprehensive evaluation of the health and environmental impacts of different disinfectants is urgently needed. From this discussion, we reach a tentative conclusion that hydrogen peroxide is a green disinfectant. Its on-demand production enables a circular economy model to solve the storage issues. Water, oxygen, and electrons are the only feedstock to generate H2O2. Upon completion of disinfection, H2O2 is rapidly converted back into water and oxygen. This model adopts several principles of green chemistry to ensure overall sustainability along the three stages of its whole life cycle, i.e., production, disinfection, and decomposition. Physical methods, particularly UV irradiation, also provide sustainable disinfection with minimal health and environmental impacts. [ABSTRACT FROM AUTHOR]

Inactivated vaccines are promising tools for tackling the COVID-19 pandemic. We applied several protocols for SARS-CoV-2 inactivation (by β-propiolactone, formaldehyde, and UV radiation) and examined the morphology of viral spikes, protein composition of the preparations, and their immunoreactivity in ELISA using two panels of sera collected from convalescents and people vaccinated by Sputnik V. Transmission electron microscopy (TEM) allowed us to distinguish wider flail-like spikes (supposedly the S-protein's pre-fusion conformation) from narrower needle-like ones (the post-fusion state). While the flails were present in all preparations studied, the needles were highly abundant in the β-propiolactone-inactivated samples only. Structural proteins S, N, and M of SARS-CoV-2 were detected via mass spectrometry. Formaldehyde and UV-inactivated samples demonstrated the highest affinity/immunoreactivity against the convalescent sera, while β-propiolactone (1:2000, 36 h) and UV-inactivated ones were more active against the sera of people vaccinated with Sputnik V. A higher concentration of β-propiolactone (1:1000, 2 h) led to a loss of antigenic affinity for both serum panels. Thus, although we did not analyze native SARS-CoV-2 for biosafety reasons, our comparative approach helped to exclude some destructive inactivation conditions and select suitable variants for future animal research. We believe that TEM is a valuable tool for inactivated COVID-19 vaccine quality control during the downstream manufacturing process. [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]

Industrial expansion has increased the discharge of contaminated wastewater. Wastewater can be treated by adsorption with petroleum‐based hydrogels but the materials are not biodegradable and therefore cause secondary toxic waste. In this work, hydrogel composites are prepared based on non‐biodegradable polyacrylamide and biodegradable materials of cassava starch (CS) and poly(vinyl alcohol). The effect of CS content on the porous structure is studied. The highest water absorption capacity of 74 g g−1 is obtained from a hydrogel 30 wt% of CS. Within 4 h, the hydrogel effectively adsorbs the cationic dyes methylene blue (MB) and crystal violet, and the anionic dyes congo red and reactive orange. The maximum adsorption capacity toward MB is 993 mg g−1. Experimental data indicate a monolayer adsorption via chemisorption. Silica‐coated ZnO photocatalyst particles are synthesized via a sol–gel method and coated on the outer surface of the hydrogel. Under sunlight, the hydrogel composite degrades almost 90% of adsorbed dye. The hydrogel composite is capable of effective photodegradation for at least three cycles under artificial UV irradiation and four cycles under sunlight, but adsorption capacity remains higher than 80% at the eighth cycle. The hydrogel composite also shows antibacterial activities, indicating an additional beneficial property for industrial wastewater treatment. [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]

In our previous study, we found that Enterobacter strain TS3 is able to decolorize of textile wastewater (TW) through a fermentative polyhydroxyalkanoate (PHA) production process. This current study aimed to enhance the ability of strain TS3 to produce PHA using TW by a UV-light radiation-based mutagenesis system, and to enhanced PHA by multiple-round UV-light radiation. The highest PHA-production mutant was obtained in the second rounds of UV-light radiation. The radiation time was optimized to 40 s in the first round followed by 20 s at a distance of 60 cm of plates. The mutant strain TS3-UV2 yielded PHA production at 84.96 ± 1.32% cell dry mass (CDM). The highest PHA concentration (88.66 ± 1.00% CDM) is achieved at pH 7, 150 rpm and 35 °C for 60 h of incubation. Under optimal condition, the mutant yielded 0.53 times more production of PHA than the parent strain. Moreover, the decolorization efficiency of TW was observed to be 72.32% under optimal PHA conditions. Interestingly, the mutant strain could synthesize the medium-co-long-chain-length PHA (mcl-co-lcl PHA), while short-co-medium-chain-length PHA (scl-co-mcl PHA) was observed in the wild type using TW as substrate. Therefore, the mutation and optimization strategy appear to be suitable for producing high-density PHA. [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]

Incorporation of antibacterial Ag nanoparticles (AgNPs) is thought to effectively control the biofouling of the thin-film composite (TFC) nanofiltration membrane for efficient desalination. In this study, a UV photoreduction reaction was employed for the first time to introduce AgNPs into the separation active layer of nanofiltration membrane to avoid the normal membrane blockage by conventional blending method. The additional merit of the UV irradiation was the partial oxidation of membrane surface, which provides more hydrophilic groups. Compared with the pristine TFC membrane, the AgNPs-loaded (TFC-Ag) membrane possessed much better hydrophilic property (with an increase in pure water flux by 99%), and maintained high salt rejection efficiency. The high antibacterial performance of the TFC-Ag membrane was demonstrated by the 96% inhibition efficiency to Escherichia coli. Besides, the TFC-Ag membrane only showed a trace amount of Ag+ release in the static and dynamic tests, showing great stability for water treatment. This study provides an innovative strategy for the in-situ production of metallic nanoparticles to modify the nanofiltration membrane and to improve its water flux and anti-bacterial performance. [ABSTRACT FROM AUTHOR]

Eco-friendly stannic oxide nanoparticles functionalized with gallic acid (SnO2/GA NP) were synthesized and employed as a novel photocatalyst for the degradation of citalopram, a commonly prescribed antidepressant drug. SnO2/GA NP were characterized using high-resolution transmission electron microscopy, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller measurements and X-ray diffraction. A validated RP-HPLC assay was developed to monitor citalopram concentration in the presence of its degradation products. Full factorial design (24) was conducted to investigate the effect of irradiation time, pH, SnO2/GA NP loading and initial citalopram concentration on the efficiency of the photodegradation process. Citalopram initial concentration was found to be the most significant parameter followed by irradiation time and pH, respectively. At optimum conditions, 88.43 ± 0.7% degradation of citalopram (25.00 µg/mL) was obtained in 1 h using UV light (1.01 mW/cm2). Citalopram kinetics of degradation followed pseudo-first order rate with Kobs and t0.5 of − 0.037 min−1 and 18.73 min, respectively. The optimized protocol was successfully applied for treatment of water samples collected during different cleaning validation cycles of citalopram production lines. The reusability of SnO2/GA NP was studied for 3 cycles without significant loss in activity. This approach would provide a green and economic alternative for pharmaceutical wastewater treatment of organic pollutants. [ABSTRACT FROM AUTHOR]

Wet spinning was studied for lignocellulose nanofibrils (TOLCNF) obtained by TEMPO oxidation and mechanical defibrillation of deep eutectic-like solvent-treated lignocellulose. First, the morphological characteristics, water retention value, and specific surface area of the TOLCNF were studied. The effects of the TOLCNF concentration (1.5, 2.0, and 2.5 wt%) and spinning rate (0.1, 1.0, and 10 mL/min) on the wet-spun filament diameter, orientation index, and tensile properties were studied. With an increase in the TOLCNF concentration, the average diameter increased, whereas the orientation index and tensile strength decreased. An increased spinning rate resulted in an increased orientation index and tensile strength but a decrease in the average diameter. To further extend their applicability, Ag nanoparticles (AgNPs) were grown in situ on the filament surface using UV irradiation. Spherical AgNPs with diameters of 30 to 90 nm were observed using scanning electron microscopy. An increased AgNP content improved the tensile strength and elastic modulus of the filaments. [ABSTRACT FROM AUTHOR]

Different applications used nano materials such as Nano-Oxides or Nano-Salts i.e. silver nanoparticles (Ag NPs.) or zinc oxide Nano-particles (ZnO NPs.) to acquire antibacterial activity for cotton fabrics. In the present study chitosan treated cotton fabrics followed by nano treatment via Ag NPs. or ZnO NPs., or mixture of both nano-materials had been subjected to UV irradiation using medium pressure mercury lamp with a light intensity on the fabric of about 15mW/cm2 to produce an enhancement in the anti-bacterial activity against Gram +ve and Gram –ve bacteria i.e. St. coccus and E. coli. The produced yield was assured with FT-IR and scanning electron microscope. The best result for Gram negative bacteria (Escherichia coli) obtained by using mixture of (Ag NPS (100ppb) + ZnO NPS (8% o.w.s) + UV) as well as for Gram positive bacteria (Staphylococcus Aureus) the best result obtained by using mixture of (Ag NPS (100ppb) + ZnO NPS (8% o.w.s) + UV). [ABSTRACT FROM AUTHOR]

Dynamic mechanical relaxation spectroscopy is used to study the relaxation behavior of elastic alkyl(met) polymers. The items of interest are acrylates on metal substrates before and after UV irradiation of different durations. Analysis is based on comparing the intensity of local dissipative relaxation in irradiated and non-irradiated polymers, along with their glass transition temperatures and elastic properties. [ABSTRACT FROM AUTHOR]

We report here that exposure to UV radiation at a dose of 151 J/m2 increased the activity of free bromelain (EC 3.4.22.4) by 86%, while UV radiation at a dose of 6040 J/m2 caused a decrease in its catalytic activity by 15%. No change in the molecule size of the enzyme (radius) was observed within the dose range of 151–6040 J/m2. Bromelain adsorption on high-molecular-weight (350 kDa) chitosan matrix led to the enzyme preparation retaining its activity at 97% after irradiation at all doses within the range used; immobilization on medium molecular weight (200 kDa) chitosan allowed it to retain up to 89% of the activity level. Analysis of IR spectra of immobilized bromelain has shown that there were no significant changes in the characteristic amide I, amide II, and amide III bands. Therefore, it can be stated that chitosan matrix acts as a photomodulator for the enzyme sorbed on it. [ABSTRACT FROM AUTHOR]

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The COVID-19 pandemic has spread rapidly around the world; some countries have introduced controls on imported products, including testing for viral nucleic acids. In this work, the influence of disinfectants for treating various SARS-CoV-2-contaminated surfaces on the detection of viral RNA fragments in swabs from these surfaces was analyzed using quantitative RT-PCR. Quaternary ammonium salt, hydrogen peroxide, 1-propanol, and sodium salt of dichloroisocyanuric acid, as well as ultraviolet irradiation, were tested as such disinfecting agents. Our results show that without exposure to disinfectants, viral RNA can be detected on the surface of all examined materials for at least 3 days. UV irradiation or irrigation with a disinfectant containing 0.2% active chlorine had the greatest effect on the decontamination of nonporous surfaces as measured by RT-PCR of swabs from these surfaces. Irrigation with disinfectants of porous surfaces (cardboard) had practically no effect on the detection of SARS-CoV-2 RNA by RT-PCR. [ABSTRACT FROM AUTHOR]

All living organisms have evolved DNA damage response (DDR) strategies in coping with threats to the integrity of their genome. In response to DNA damage, Sulfolobus islandicus activates its DDR network in which Orc1-2, an ortholog of the archaeal Orc1/Cdc6 superfamily proteins, plays a central regulatory role. Here, we show that pretreatment with UV irradiation reduced virus genome replication in S. islandicus infected with the fusellovirus SSV2. Like treatment with UV or the DNA-damaging agent 4-nitroquinoline-1-oxide (NQO), infection with SSV2 facilitated the expression of orc1-2 and significantly raised the cellular level of Orc1-2. The inhibitory effect of UV irradiation on the virus DNA level was no longer apparent in the infected culture of an S. islandicus orc1-2 deletion mutant strain. On the other hand, the overexpression of orc1-2 decreased virus genomic DNA by ~10²-fold compared to that in the parent strain. Furthermore, as part of the Orc1-2-mediated DDR response genes for homologous recombination repair (HRR), cell aggregation and intercellular DNA transfer were upregulated, whereas genes for cell division were downregulated. However, the HRR pathway remained functional in host inhibition of SSV2 genome replication in the absence of UpsA, a subunit of pili essential for intercellular DNA transfer. In agreement with this finding, lack of the general transcriptional activator TFB3, which controls the expression of the ups genes, only moderately affected SSV2 genome replication. Our results demonstrate that infection of S. islandicus by SSV2 triggers the host DDR pathway that, in return, suppresses virus genome replication. [ABSTRACT FROM AUTHOR]

Chitosan is one of the promising compounds for use in various fields of medicine. However, for successful application, materials based on it must be insoluble in water and have specified physical and mechanical properties. In this work, we studied the interaction of N-methylolacrylamide (NMA) and chitosan upon concentration of the solutions, both under the action of UV radiation and without it, which results in curing of the polymer matrix. The main products, proposed mechanisms of the crosslinking reaction, and the influence of external conditions on these processes have been revealed using NMR, IR, and UV spectroscopy. It was found that the reaction proceeds along three pathways. The main reactions proceed with the amino groups of chitosan, and the hydroxymethyl and vinyl groups of NMA. Studies have shown that for the formation of insoluble materials based on chitosan, the best content in the initial cast solution is 2 wt% of chitosan at 0.25 wt% concentration of NMA. Films formed from such solutions possessed high strength and deformation characteristics, namely an elastic modulus of about 1500 GPa, a strength of about 30 MPa, and an elongation at break of about 100%. [ABSTRACT FROM AUTHOR]

The aim of this study is degradation of ibuprofen (IBP) widely used analgesic and anti-inflammatory drug in the pharmaceutical sector by advanced oxidation processes as photo-catalysis, photolysis and Like photo-Fenton processes. The Fe-TUD-1 material was elaborated by ultrasonic method and characterized by XRD, BET, FTIR and RD techniques. The photo-catalytic properties of Fe-TUD-1 were evaluated via IBP degradation by varying the material amount, the pH, and the IBP concentration. The evolution of the IBP concentration was measured by UV–visible spectrophotometer and liquid chromatography, while the mineralization percentage was monitored by the determination of chemical oxygen demand. The material has a small particles size with a specific surface area above 81 m2/g and an indirect optical band gap energy (Eg = 2.94 eV). The efficiency IBP removal increased to 72% whereas 50% of DOC is removed after 210 min of irradiation. The optimum conditions determined at room temperature were [IBP] = 50 mg/L, [Fe-TUD-1] = 0.41 g/L and pH 11. [ABSTRACT FROM AUTHOR]

In the last few decades, environmental contaminants (ECs) have been introduced into the environment at an alarming rate. There is a risk to human health and aquatic ecosystems from trace levels of emerging contaminants, including hospital wastewater (HPWW), cosmetics, personal care products, endocrine system disruptors, and their transformation products. Despite the fact that these pollutants have been introduced or detected relatively recently, information about their characteristics, actions, and impacts is limited, as are the technologies to eliminate them efficiently. A wastewater recycling system is capable of providing irrigation water for crops and municipal sewage treatment, so removing ECs before wastewater reuse is essential. Water treatment processes containing advanced ions of biotic origin and ECs of biotic origin are highly recommended for contaminants. This study introduces the fundamentals of the treatment of tertiary wastewater, including membranes, filtration, UV (ultraviolet) irradiation, ozonation, chlorination, advanced oxidation processes, activated carbon (AC), and algae. Next, a detailed description of recent developments and innovations in each component of the emerging contaminant removal process is provided. [ABSTRACT FROM AUTHOR]

Nano-crystalline titanium dioxide (TiO2) photocatalyst has been extensively utilized in the last few decades because of its strong oxidizing power, redox selectivity, and higher photocatalytic performance. In this work, TiO2 nanoparticle (NPs) was synthesized, characterized, and applied for the degradation of methyl orange (MO) dye in an aqueous solution under UV and solar light irradiations. The XRD results showed dominated anatase phase (82%) with a smaller crystalline size (18.23 nm). A rough surface with a uniform spherical shape was observed by SEM analysis. FTIR and UV–Vis/DRS spectroscopy confirmed the stretching vibration of the hydroxyl groups and higher absorption edge towards longer wavelength with smaller bandgap energy (3.12 eV) of TiO2 lattice structure. The activity of TiO2 NPs was carried out from the degradation of MO dye as a model contaminant for textile effluent in presence of UV/solar irradiation. The photodegradation efficiency of MO dye (15 mg L−1) was observed at 85.90% and 96.38% for 0.150 g and 0.030 g of TiO2 NPs at natural pH (7.0), after 5 h of UV and solar light irradiation. The respective rate constants were determined to be 0.0063 min−1 and 0.01 min−1 for UV and simulated solar light irradiation respectively, and exhibited the best-fitted kinetic model of pseudo-first-order. The photodegradation efficiency was increased with the decrease of pH, while efficiency decreased with an increase in initial dye concentration. The obtained result from TiO2 NPs was compared with commercially available Degussa P25 catalyst. The photocatalyst reusability test and reaction mechanism were also evaluated. The study suggests that TiO2 NPs are a promising photocatalyst that can be used for the degradation of organic dye compounds from textile wastewater towards the sustainable management of environment.