Influence Of UV Light Research Articles

Characterization of Bacterial Isolates from Freshwater Environments in Livingstone Island, Antarctica, Using Cultivation and Molecular Methods

The present research work summarizes the investigation of the microbial characteristics of bacterial isolates obtained from freshwater samples collected at various points throughout the Bulgarian Antarctic base “St. Kliment Ohridski” on Livingstone Island. The ability of microorganisms in psychrophilic envi¬ronments to survive and reproduce at low temperatures, lack of nutrients, and high UV radiation, suggests that they have developed specific mechanisms to overcome these extreme conditions. To understand the range of influence of these environmental factors standard microbiological techniques were used. The re¬search provides data on the influence of UV light, temperature range, determination of minimum inhibitory concentration (MIC) to different heavy metals, and 16S rDNA taxonomic identification of the isolates. Ant¬arctic microorganisms are of great interest in food, textile, and brewing industries, production of detergents, etc. The microbial composition in such hostile habitats still little affected by the anthropogenic factor is es¬sential for understanding the potential of psychrophilic microorganisms in different practical applications.

Study on the Influence of UV Light on Selective Antibacterial Activity of Silver Nanoparticle Synthesized Utilizing Protein/Polypeptide-Rich Aqueous Extract from The Common Walkingstick, Diapheromera femorata.

Common walkingstick (Diapheromera femorata) aqueous extract (CWSAE) can induce the synthesis of useful bionanomaterials. CWSAE is rich in water-soluble organic compounds such as proteins and polypeptides that function as reducing/stabilizing agents for nanoparticle formation from Ag+ ion precursors. The synthesized AgNPs exhibited a moderately uniform size, with the majority falling within the range of 20-80 nm. These AgNPs were UV-treated and tested as antibacterial agents to inhibit the growth of four pathogenic bacteria (Burkholderia cenocepacia K-56, Klebsiella pneumoniae ST258, Pseudomonas aeruginosa PAO1, and Staphylococcus aureus USA300), as well as one common bacterium (Escherichia coli BW25113). The disk diffusion test demonstrated that the UV-treated AgNPs significantly and selectively inhibited the growth of Staphylococcus aureus USA300 and P. aeruginosa, while showing a small effect on the other two species. This suggests the potential application of green-chemically synthesized AgNPs as selective antibacterial agents. Furthermore, we studied the effects of short-term (1-2 min) and long-term (5-30 min) UV treatment on the selective cytotoxicity of the AgNPs and found that the cytotoxicity of the AgNPs could depend on the duration of UV exposure against certain bacteria.

Influence of UV light, ultrasound, and heat treatment on the migration of bisphenol A from polyethylene terephthalate bottle into the food simulant

This research examined the impacts of ultrasound, UV light, storage time, and temperature on the leaching of bisphenol A (BPA) from polyethylene terephthalate (PET) drinking water bottles in Turkey. The initial phase of the investigation encompassed the quantification of BPA in two distinct brands of bottled water. Samples were extracted by solid- phase extraction (SPE) and analyzed by high performance liquid chromatography with fluorescence detection (HPLC‐FLD). According to the results in the first part, the highest BPA levels were found in bottled water. In the second part of the study, 10 to 30 min of ultrasound treatment increased the BPA migration with increased time in simulants. In the first and second weeks of storage at 25 °C, the effect of storage on BPA migration was below the detection limit (<LOD) in simulants. However, at 35 °C and 45 °C, BPA concentration increased with increased temperature. According to these results, increasing the storage temperature to 35 °C and 45 °C increased the BPA pass faster than the increase in storage time. When simulants in PET bottles were exposed to UV light for 1 and 6 h, BPA transitions higher from 6 to 1 h was found in simulants. Except for first-brand water samples, the passing of bisphenol A was found to comply with the European Food Safety Authority (EFSA) criteria in this study.

Synephrine photodegradation study: Degradation kinetic, in silico and LC-ESI-MS analysis of major degradation product, and in vitro toxicological study

The exponential and indiscriminate use of dietary supplements and weight loss compounds has become a significant public health problem, drawing attention from national and international regulatory agencies. The objective of this study is to provide evidence of how the quality of synephrine varies over time under the influence of UV light. Photodegradation kinetic studies were conducted under UV light to assess the degradation of synephrine. In silico and LC-ESI-MS studies were utilized to identify the major degradation product of synephrine. Additionally, a biological safety study was conducted to evaluate the effects of the photodegraded synephrine in comparison to the intact molecule. In the photodegradation kinetic studies, the drugs exhibited a second-order reaction rate under the specific experimental conditions applied. Key kinetic parameters such as rate constant, half-life (t1/2), and the time at which 90% of the original drug concentration remained were determined. Based on the in silico studies and confirmation of molecular weight, a comprehensive degradation pathway of the drug and the identification of its major degradation product could be suggested without the need for purification processes or complex isolation techniques. The results revealed the higher reactivity of the side chain amino group, indicating the formation of chroman amino. Additionally, the biological safety study demonstrated that the degraded sample had an impact on cell viability and exhibited genotoxic potential. The quality of synephrine changes over time under the influence of light. These findings emphasize the importance of exercising caution during the handling, manufacturing, and storage of pharmaceutical preparations or food supplements containing synephrine.

Effect of Aromatic Rings in AESO-VDM Biopolymers on the Local Free Volume and Diffusion Properties of Polymer Matrix

In this work, the influence of aromatic rings on the local free volume of cured mixtures of acrylate epoxidized soybean oil (AESO) and vanillin dimethacrylate (VDM) was investigated. Cross-linking took place under the influence of UV light in the presence or absence of a photoinitiator. The local free volume and its homogeneity were characterized using the Positron Annihilation Lifetime Spectroscopy (PALS) technique. It was found that increasing the content of VDM, which contains aromatic rings, caused a decrease in the local free volume of the cured polymer network, with consequences for the diffusion properties of the polymer, which were tested for the case of water. Another consequence of increasing the content of VDM was a decrease in the conversion of double bonds in the finally cured samples, characterized by near-infrared spectroscopy (NIR). This finding illustrates a case where the decrease in free volume is not necessarily related to an increase in the crosslinking density of the polymer, but is a consequence of the presence of an increase in the occupied volume of aromatic rings in the volume of the polymer.

Influence of Weathering on the Degradation of Cellulose Acetate Microplastics Obtained from Used Cigarette Butts.

Cellulose acetate is used in many applications, including for cigarette filters. Unfortunately, unlike cellulose, its (bio)degradability is under question, yet it often ends up uncontrolled in the natural environment. The main purpose of this study is to compare the effects of weathering on two types of cigarette filter (classic filters and newer filters that have more recently arrived on the market) following their use and disposal in nature. Microplastics were prepared from polymer parts of used (classic and heated tobacco products-HTP) cigarettes and artificially aged. TG/DTA, FTIR, and SEM analyses were performed both before and after the aging process. Newer tobacco products contain an additional film made of a poly(lactic acid) polymer which, like cellulose acetate, burdens the environment and poses a risk to the ecosystem. Numerous studies have been conducted on the disposal and recycling of cigarette butts and cigarette butt extracts, revealing alarming data that have also influenced the decisions of the EU, who addressed the disposal of tobacco products in the EU Directive (EU) 2019/904. Despite this, there is still no systematic analysis in the literature evaluating the impact of weathering (i.e., accelerated aging) on the degradation of cellulose acetate in classic cigarettes compared with that in newer tobacco products that have recently appeared on the market. This is of particular interest given that the latter have been promoted as being healthier and environmentally friendly. The results show that in cellulose acetate cigarette filters the particle size decreased after accelerated aging. Also, the thermal analysis revealed differences in the behavior of the aged samples, while the FTIR spectra showed no shifts in the position of the peaks. Organic substances break down under UV light, which can be seen by measuring the color change. The PLA film was found to be more stable than cellulose acetate under the influence of UV light.

Evaluation of the antiviral activity of ultraviolet light and zinc oxide nanoparticles on textile products exposed to Avian coronavirus

This research has developed a piece of sanitizing locker-model equipment for textiles exposed to avian coronavirus, which has been put under the influence of UV light, UV + zinc oxide nanoparticles (phytosynthesized ZnONP), and water + UV, and, in turn, under the influence of the exposure time (60, 120, 180 s). The results linked to the phytosynthesis of ZnONP indicate a novel method of fabricating nanostructured material, nanoparticles with spherical morphology and an average size of 30 nm. The assays were made based on the viral viability of avian coronavirus according to the mortality of SPF embryonated eggs and a Real-Time PCR for viral load estimation. This was a model to evaluate the sanitizing effects against coronaviruses since they share a very similar structure and chemistry with SAR-CoV-2. The influence of the type of textile treatment evidenced the potential effect of the sanitizing UV light, which achieved 100% of embryo viability. The response of the ZnONP + UV nebulization showed a notorious influence of photoactivation according to the exposure time, and the 60-s treatment achieved a decrease of 88.9% in viral viability, compared to 77.8% and 55.6% corresponding to the 120 and 180-s treatments, respectively. Regarding the decrease in viral load between the types of treatments, UV 180 s reduced 98.42% and UV 60 s + ZnONP reduced 99.46%, respectively. The results show the combinatorial effect of UV light and zinc nanoparticles in decreasing the viral viability of avian coronavirus, as a model of other important coronaviruses in public health such as SARS-CoV-2.

N-Doped Carbon Dots and ZnO Conglomerated Electrodes for Optically Responsive Supercapacitor Applications

The over-dependence of human society on fossil fuels for energy is exhausting the level of such non-renewable energy sources. Alternative energy storage systems have gained more popularity recently to counter this issue. In this context, we report the fabrication of N-doped carbon dot (N-CD)-decorated ZnO-based electrodes for supercapacitor applications. Due to the light-responsive nature of the N-CDs and ZnO, the electrode was also responsive under the influence of UV light. After the experimental tests, it was found that the areal capacitance value of the supercapacitor increased upto ∼58.9% when illuminated compared to that under the dark conditions. Moreover, the device showed a maximum areal capacitance of 2.6 mF/cm2 after photocharging and galvanostatically discharging at a current density value of 1.6 μA/cm2, which is quite comparable with the previously reported data. The doping of N-CDs with ZnO showed a significant improvement in the areal capacitance value under both illuminated (∼58.64%) and dark conditions (∼22.08%) compared to the case of pristine ZnO, which justifies the purpose of attaching N-CDs with ZnO. Therefore, in brief, we have fabricated a photoresponsive electrode material for supercapacitor application by combining N-CDs and ZnO. An explicit electrochemical characterization of the electrode was also done to identify the contribution from diffusion-controlled capacitance and double layer capacitance, and it was observed that the diffusion-controlled capacitance gets reduced from 59.1 to 33.6% when the scan rate is increased from 2 to 75 mV/s. Moreover, a detailed study has also been done to understand the reaction mechanism. It was confirmed that the defects in the electrode material played a vital role in the intercalation of K+ ions.

Accelerated UV stress testing and characterization of PV-modules: Reliability analysis using different encapsulants and glass sheets

Ethylene vinyl acetate (EVA) is the most commonly used encapsulant material in photovoltaic (PV) module fabrication. However, during long-term operation in the field under hot and dry climates, it turns yellow and finally brown due to action of ultraviolet (UV) light. Therefore, UV-light is a major concern causing photodegradation of encapsulant and significant loss in maximum power (Pmax) of PV-module. The main objective of this study is to provide deeper insights into degradation of electrical parameters in PV-modules under influence of UV-light and temperature, and minimize the impact of UV induced degradation (UVID) by replacing the encapsulant EVA with poly vinyl butyral (PVB). Four polycrystalline PV-modules, fabricated in different combinations from two types of encapsulants, namely PVB and EVA, and glass sheets, namely soda-lime and quartz, are subjected to an accelerated UV stress test for 350 h. Visual inspection, electroluminescence, infrared imaging, insulation resistance, wet leakage current, and maximum power determination tests were performed to characterize PV-modules intermittently throughout accelerated UV stress test. Based on obtained electrical parameters, PVB/soda-lime experienced the lowest 3% loss in Pmax, whereas EVA/quartz experienced the highest 7% loss in Pmax. In other two samples, EVA/soda-lime and PVB/quartz, Pmax reduced by 4% and 5% respectively.

Phytochemically and PVP stabilized TiO2 nanospheres for enhanced photocatalytic and antioxidant efficiency

In this paper, TiO2 NPs has been fabricated by via microwave-assisted chemically and biologically methods. The anatase and rutile phases of TiO2 NPs were obtained by calcinating them at temperatures of 400 and 700 °C, respectively. In these two different approaches, the biomolecules like alkaloids, steroids, glycosides, etc. present in Tinospora Cordifolia (TC) and polyvinylpyrrolidone (PVP), respectively, have been reported to act as stabilizing agents for TiO2 NPs. XRD, Raman, UV–visible, SEM-EDS and TEM spectroscopic techniques were used to analyze distinct physical and chemical properties. The so-synthesized TiO2 NPs exist as tetragonal crystal lattice with spheroidal shape and sizes between 8 and 40 and 15–98 nm. Under the influence of UV light, the photocatalytic activity was examined against two common industrial dyes, methyl orange (MO) and methylene blue (MB) by using synthesized TiO2 NPs. Up to 98% and even 100% of MO and MB dye degradation have been seen in rare circumstances. The antioxidant potential of TiO2 NPs has been evaluated up to 91% and 74% from the biologically and chemically methods, respectively.

Влияние морфологических и структурных параметров тетраподов ZnO на их активность в реакции фотокаталитической деградации ципрофлоксацина

The influence of morphological and structural parameters of microdimensional tetrapods ZnO on their activity in the reaction of photocatalytic degradation of ciprofloxacin under the influence of UV light has been studied. The greatest activity (velocity constant 25.5 · 10-3 min-1) was demonstrated by unalloyed ZnO tetrapods obtained in the presence of Au in the initial charge, which had the smallest geometric parameters. The photocatalytic activity of tetrapods is explained by the highly defective structure of their near-surface layers. Photoactive microsize tetrapods ZnO, synthesized by the carbothermal method, can be used in the mineralization of toxic organic compounds.

Facile hydrothermal synthesis of cerium oxide/rGO nanocomposite for photocatalytic and supercapacitor applications

The unique features of graphene materials make them excellent catalysts for photodegradation and energy applications. In the present work, CeO2/reduced graphene oxide (rGO) nanocomposites were prepared by a simple one-pot hydrothermal method. The nanocomposite is found to have a mesoporous structure with a surface area of 100.129 m2g−1. With the preferentially small surface area of the nanocomposite and the ability of the rGO to act as electron acceptor, the CeO2/rGO photocatalyst supresses the electron-pair recombination during photodegradation, thereby achieving a quick and efficient degradation of Direct Green dye. Under the influence of UV light, the CeO2/rGO degrades 84.1% of the dye which is 1.5 times more efficient than blank CeO2. Further, due to the conducting nature of rGO, the nanocomposites have also been evaluated for their electrochemical performance. It has been found that the addition of rGO results in a high capacitance (410.8 Fg−1 at current density of 1.0 Ag−1) and stability (94% after 500 cycles) of the CeO2/rGO electrode. The present work projects the excellent charge transport capability of rGO based CeO2 nanomaterials for dual applications in the areas of photocatalysis and electrocatalysis.

The influence of UV light on the course of fluorescent enzyme assays

Experiments were carried out to illustrate the effect of UV light on the course of the enzymatic reaction of the coumarin derivative. Only the pulsating light of the UV diode gives the correct results for the determination of the kinetic constants of the enzymatic reaction. The enzyme concentration limit was found where the description of the M-M model breaks. It was shown that the system determines the kinetic parameters of enzymatic reactions: Vmax —the maximum rate of reaction and KM—the Michaelis constant. This method produces kinetic constants calculated from the changes in enzyme product concentration using the Michaelis-Menten model. To verify the results, we used a statistical analysis that checks the correctness of the model used.

Osseointegration of Zirconia Implants after UV-Light or Cold Atmospheric Plasma Surface Treatment In Vivo.

The influence of UV light and non-thermal plasma on the osseointegration of yttria-stabilized zirconia implants (Y-TZP) comparing the two methods is unclear. The aim of this study was to show the influence of these methods on the osseointegration of dental zirconia implants in an animal model. A total of 54 implants were either untreated, treated with UV light (UV), or non-thermal oxygen plasma for 12 min and inserted into the parietal bones of six domestic pigs. The animals were sacrificed after a healing interval of two, four, and nine weeks. The degree of osseointegration was determined using histomorphometric determination of bone-to-implant contact values (BIC) and the bone-to-implant contact values within the retentive parts of the implants (BAFO). BIC values decreased in all groups after four weeks of healing and re-increased after nine weeks in all groups. BAFO increased significantly over time in all groups. However, there were no statistically significant differences in BIC and BAFO values between the control group and the test groups and over time. Clinical studies may follow to confirm the influence of cold plasma and UV light on the healing and survival of zirconia implants.

COVID-19 Face Masks as a Long-Term Source of Microplastics in Recycled Urban Green Waste

Following the outbreak of the COVID-19 pandemic in March 2020, many governments recommended or mandated the wearing of fitted face masks to limit the transmission of the SARS-CoV-2 virus via aerosols. Concomitant with the extensive use of non-sterile, surgical-type single-use face masks (SUM) was an increase of such masks, either lost or discarded, in various environmental settings. With their low tensile strength, the spunbond and melt-blown fabrics of the SUM are prone to shredding into small pieces when impacted by lawn cutting equipment. Observations highlight the absence of smaller pieces, which are either wind-dispersed or collected by the mower’s leaf catcher and disposed together with the green waste and then enter the municipal waste stream. As proof-of-concept, experiments using a domestic lawn-mower with different height settings and different grass heights, show that 75% of all pieces of SUM fabric caught in the catcher belonged to sizes below 10 mm2, which under the influence of UV light will decay into microfibers. The implications of SUM generated microplastics are discussed.

Photocatalytic Degradation of Diazo Dye over Suspended and Immobilized TiO2 Catalyst in Swirl Flow Reactor: Kinetic Modeling

The degradation kinetics of Direct Blue 15 (DB15), a diazo dye, were studied over a suspended and immobilized TiO2 catalyst. For all experiments, the kinetics experiments were performed in a swirl flow photoreactor under the influence of UV light. The effect of different parameters: dye concentration, catalyst loading, and light intensity, on the DB15 kinetics was investigated. The kinetic rates were assessed using apparent (ka) approach, a single value of reaction rate (kr) and adsorption constant (K), and approach of kr as of variable. The DB15 mineralization was discussed as well. Using a dip-coating device, the P25 catalyst was deposited on a Pyrex glass. The thin film surface characterization was examined. The coated catalyst was evaluated by checking the effect of two variables: initial dye concentration and light intensity on the DB15 kinetics. In terms of the ka approach, the results demonstrated that DB15 degradation is described by the pseudo first-order kinetics model. The Langmuir-Hinshelwood (L-H) model was fitted well with the experimental data for the number of process variables. L-H constant kr was determined as a function of three parameters: initial dye concentration, catalyst loading, and light intensity. The ka values were evaluated and compared with experimental results. In terms of three variables, ka can be expressed as ka=0.15 [C]o−0.69 [W]0.73 I0.91 1+0.17 [C]o while the empirical model results in the following expression, ka=0.77 [C]o−1.65 [W]0.73 Io0.89. It was observed that 83.64% mineralization was achieved after a period of 16 hrs. In terms of immobilized catalyst, the DB15 degradation kinetics was described by a pseudo first-order model for different dye concentrations. Meanwhile, a power-law model described the impact of light intensity on dye kinetics. In addition, the coated catalyst was successfully reusable with high efficiency for up to four cycles.

The Influence of UV Light on Photodegradation of Acetylsalicylic Acid.

Photodegradation of the aqueous solutions of acetylsalicylic acid, in the absence (ASA) and the presence of excipients (ASE), is demonstrated by the photoluminescence (PL). A shift of the PL bands from 342 and 338 nm to 358 and 361–397 nm for ASA and ASE in solid state and as aqueous solutions was reported. By exposure of the solution of ASA 0.3 M to UV light, a decrease in the PL band intensity was highlighted. This behavior was revealed for ASA in the presence of phosphate buffer (PB) having the pH equal to 6.4, 7, and 8 or by the interaction with NaOH 0.3 M. A different behavior was reported in the case of ASE. In the presence of PB, an increase in the intensity of the PL band of ASE simultaneously with a change of the ratio between the intensities of the bands at 361–364 and 394–397 nm was highlighted. The differences between PL spectra of ASA and ASE have their origin in the presence of salicylic acid (SAL). The interaction of ASE with NaOH induces a shift of the PL band at 405–407 nm. Arguments for the reaction of ASA with NaOH are shown by Raman scattering and FTIR spectroscopy.

Improvement of PES Nanocomposit Membrane Performance Through UV and ZNO Concentration for Refinery Waste Water Purification

Wastewater is generated from the process of purifying large amounts of water. Refinery wastewater can be purified with PES-ZnO nanocomposite membrane technology. Membrane modification to reduce membrane fouling. Therefore, it is important to provide a low-fouling (non-fouling) membrane. However, currently the formation of fouling and clean water quality standards has not been met. Therefore, researchers studied the use of materials that can overcome membrane impurities and an efficient clean water production system. In addition, one alternative to improve membrane performance is to use nanocomposites (ZnO). The membrane was made with a concentration of PES 18 wt% and ZnO 0.5; 1; 1.5% by weight. with the influence of UV light on the membrane for 1,5,10 minutes at a temperature of 180°C. SEM analysis was used to show that the PES membrane has larger pores. Angle contact analysis was also carried out to show ZnO nanoparticles can improve the hydrophilic properties of membranes. For this reason, a TDS analysis is carried out, namely Cl−, S2 − and turbidity. From this analysis shows significant results with membrane performance, modification with UV radiation and the addition of PVA / PEG have interrelated effects to improve membrane performance.

Spectroscopic studies of UV-irradiated poly(vinyl alcohol)/elastin blends

The blends of synthetic and natural polymers are extensively investigated as materials for medical applications. Synthetic component usually ensures appropriate mechanical and physical properties while biopolymer improves biocompatibility of the material. In our work, we decided to use poly(vinyl alcohol) (PVA)—water-soluble, chemically stable, elastic polymer and elastin—a fibrous protein present in the extracellular matrix of connective tissues. The aim of our work was to study the influence of UV light on spectroscopic properties of poly(vinyl alcohol)/elastin hydrolysates blends. PVA is a rather photostable polymer while elastin possesses various chromophores in the structure capable of absorption of light λ > 200 nm. As a result of the blending, some interactions between the synthetic and biological components occur and cause the changes of photochemical stability of the new material. Our study demonstrates that the poly(vinyl alcohol)/elastin mixtures are more sensitive to UV irradiation than both components separately.

Cutting forces during drilling and selected physical and mechanical properties of the finish coating based on epoxy resin

Abstract: Cutting forces during drilling and selected physical and mechanical properties of the finish coating based on epoxy resin. Paper presents selected tests of epoxy resin coating applied to American walnut wood (Juglans nigra L.). The aim of the study was to assess the machinability of wood flooded with resin during drilling. The axial forces and torque values were adopted for the machinability criteria. The idea of the research was the thesis questioning the possibility of processing epoxy resin coatings with the application of tools and parameters used during wood processing. In addition, the influence of UV light on the obtained coating was examined and abrasion tests were carried out. It was found the resin changes its colour under the influence of UV radiation, but the change is imperceptible to an average observer. Epoxy resin is characterized by low abrasion resistance compared to commonly used paint and varnish coatings. Although solid resin is characterized by high cutting resistance while drilling, the force values do not exceed the commonly cut wood-based materials.