Doses Of UV Radiation Research Articles

Assessment the effectiveness of disinfection of household wastewater using a UV complex under experimental conditions

Introduction. One of the most effective and economically justified methods of inactivation water treatment is disinfection using UV irradiation. UV disinfection is characterized by the absence of an aftereffect, which is an undeniable advantage for wastewater treatment, since adverse environmental effects on the wastewater receiving water body are excluded. The main technological parameter that ensures proper disinfection is the UV dose. The purpose of the study is the confirmation of the effectiveness of using the technology of UV disinfection of water with a dose of at least 30 mJ/cm2 in relation to sanitary-indicative and pathogenic microorganisms that are present in the wastewater of the Moscow metropolis. Materials and methods. UV disinfection units DUV-1-87-N were used to conduct the experiment, providing a UV dose of at least 30 mJ/cm2 for water disinfection and an open UV irradiator SVETOLIT 50 for air disinfection manufactured by company LIT. Results. The use of a UV dose of at least 30 mJ/cm2 for disinfection of water with a high degree of contamination of microorganisms ensures the level of contamination of microorganisms to meet the requirements of sanitary legislation in force on the territory of the Russian Federation for disinfected wastewater allowed discharging into surface waters. Limitations. The limitations of the study are related to the equipment used for applying UV irradiation, water turbidity, and the sensitivity of microorganisms of different taxonomic groups to UV irradiation. Conclusion. The results of the conducted experimental study can serve a justification for the UV radiation dose of 30 mJ/cm2 used for effective disinfection of viral and bacterial contamination of water with high levels of microbial contamination up to the standard permissible level of microbial contamination (in accordance with SanPiN 1.2.3685-21) of treated wastewater suitable for discharge into surface waters.

Светодиодное ультрафиолетовое облучение семян декоративных растений

The article presents studies on determining the effective dose of ultraviolet irradiation when processing seeds of ornamental plants in a compact unit. A promising branch of plant grow-ing is ornamental gardening, since ornamental plants are widely used in landscaping of populated areas. In ornamental gardening, western thuja and prickly spruce are used, which reproduce by seeds. Among all the methods of seed treatment before sowing, we give preference to LED ul-traviolet irradiation (UVR), as the simplest, energy-saving, energy-efficient, environmentally friendly method. The purpose of the study is to determine the effective dose of UV irradiation of seeds of ornamental plants prickly spruce (Picea pungens Engelm) and western thuja (Thuja occi-dentalis L) to increase the germination energy and seed viability. The experiment on UFO of seeds was carried out on a compact UV LED setup with an irradiance of 17.16 W/m2 and only in the UFO-A zone (315...400 nm). The experiment was repeated four times. Each experiment in-cluded 100 seeds. The highest germination energy and maximum seed germination of prickly spruce are observed at a UFO dose of 9.9 kJ/m2 (tfact.=4.71> ttable.=2.57 at P = 0.05). The highest values of germination energy and germination in western thuja occur at a UFO dose of 2.2 kJ/m2. UFO is a good stimulator of growth processes. This method is economically advanta-geous compared to traditional chemical stimulation of seeds, energy-efficient, and environmen-tally friendly because it does not pollute the soil. Keywords: LED IRRADIATION OF SEEDS, ORNAMENTAL GARDENING, THUJA OCCIDENTAL-IS, PRICKLY SPRUCE, ENERGY SAVING, ULTRAVIOLET, PRE-SOWING SEED TREATMENT

Biosynthesis of photostable CdS quantum dots by UV-resistant psychrotolerant bacteria isolated from Union Glacier, Antarctica.

Quantum Dots (QDs) are fluorescent nanoparticles with exceptional optical and optoelectronic properties, finding widespread utility in diverse industrial applications. Presently, chemically synthesized QDs are employed in solar cells, bioimaging, and various technological domains. However, many applications demand QDs with prolonged lifespans under conditions of high-energy radiation. Over the past decade, microbial biosynthesis of nanomaterials has emerged as a sustainable and cost-effective process. In this context, the utilization of extremophile microorganisms for synthesizing QDs with unique properties has recently been reported. In this study, UV-resistant bacteria were isolated from one of the most extreme environments in Antarctica, Union Glacier at the Ellsworth Mountains. Bacterial isolates, identified through 16S sequencing, belong to the genera Rhodococcus, Pseudarthrobacter, and Arthrobacter. Notably, Rhodococcus sp. (EXRC-4A-4), Pseudarthrobacter sp. (RC-2-3), and Arthrobacter sp. (EH-1B-1) tolerate UV-C radiation doses ≥ 120J/m². Isolated UV-resistant bacteria biosynthesized CdS QDs with fluorescence intensities 4 to 8 times higher than those biosynthesized by E. coli, a mesophilic organism tolerating low doses of UV radiation. Transmission electron microscopy (TEM) analysis determined QD sizes ranging from 6 to 23nm, and Fourier-transform infrared (FTIR) analysis demonstrated the presence of biomolecules. QDs produced by UV-resistant Antarctic bacteria exhibit high photostability after exposure to UV-B radiation, particularly in comparison to those biosynthesized by E. coli. Interestingly, red fluorescence-emitting QDs biosynthesized by Rhodococcus sp. (EXRC-4A-4) and Arthrobacter sp. (EH-1B-1) increased their fluorescence emission after irradiation. Analysis of methylene blue degradation after exposure to irradiated QDs biosynthesized by UV-resistant bacteria, indicates that the QDs transfer their electrons to O2 for the formation of reactive oxygen species (ROS) at different levels. UV-resistant Antarctic bacteria represent a novel alternative for the sustainable generation of nanostructures with increased radiation tolerance-two characteristics favoring their potential application in technologies requiring continuous exposure to high-energy radiation.

Hygienic efficiency of ultraviolet disinfection of water in centralized drinking and household water supply systems (systematic review)

Introduction. Drinking water supplied to the population must be safe in epidemic terms. However, some viruses and parasites are resistant to the disinfecting effect of traditionally used agents for water treatment. The use of UV irradiation ensures the microbiological safety of water, but there are factors affecting its effectiveness. 
 The purpose of the review was to systematize scientific data on the effectiveness of the use of UV irradiation in relation to drinking water.
 Materials and methods. The search for scientific publications was carried out using literature databases MedLine/PubMed, Scopus, and Science Direct. The total number of publications was one thousand six hundred forty-six. The criteria for including the report in the systematic review were: publications in Russian or English with an available full-text version; samples for the study are water from centralized water supply systems or specially prepared microorganisms; any type of research evaluating the effectiveness of a wide range of doses of UV irradiation against microorganisms.
 Results of the analysis of publications. A systematic review included 17 reports about the effect of UV irradiation on bacteria and viruses. The subject of several studies was the resistance of protozoan cysts and helminth eggs to different doses of UV irradiation. According to the results presented in the publication, pathogenic viruses and bacteria, giardia cysts possess of the least resistance to UV irradiation (100% inactivation). 4 log-inactivation was established for Mycobacteia. E. coli and coliphages demonstrate a wide range of indicators of the resistance to ultraviolet radiation due to the diversity of the studied strains. 
 Conclusion. UV disinfection should be used as an additional method in combination with traditional reagents methods of water treatment. It is necessary to study the effect of UV irradiation on helminth eggs and protozoan cysts.

Acute exposure to ultraviolet radiation targets proteins involved in collagen fibrillogenesis.

Introduction: Exposure to chronic, low-dose UV irradiation (UVR) can lead to premature ageing of the skin. Understanding which proteins are affected by acute UVR and photo-dynamically produced reactive oxygen species (ROS) could help to inform strategies to delay photoageing. Conventional biochemical analyses can be used to characterize UVR/ROS-induced damage on a protein-by-protein basis and we have previously shown using SDS-PAGE that collagen I and plasma fibronectin are respectively resistant and susceptible to physiological doses of UVR. The aim of this study was to screen a complex proteome for UVR-affected proteins. Methods: This study employed a sensitive mass spectrometry technique (peptide location fingerprinting: PLF) which can identify structure associated differences following trypsin digestion to characterize the impact of UVR exposure on purified collagen I and tissue fibronectin and to identify UVR-susceptible proteins in an ECM-enriched proteome. Results: Using LC/MS-MS and PLF we show that purified mature type-I collagen is resistant to UVR, whereas purified tissue fibronectin is susceptible. UV irradiation of a human dermal fibroblast-deposited ECM-enriched proteome in vitro, followed by LC/MS-MS and PLF analysis revealed two protein cluster groups of UV susceptible proteins involved in i) matrix collagen fibril assembly and ii) protein translation and motor activity. Furthermore, PLF highlighted UV susceptible domains within targeted matrix proteins, suggesting that UV damage of matrix proteins is localized. Discussion: Here we show that PLF can be used to identify protein targets of UVR and that collagen accessory proteins may be key targets in UVR exposed tissues.

Evaluation of MAA Analogues as Potential Candidates to Increase Photostability in Sunscreen Formulations

Avobenzone is one of the most widely used sunscreens in skin care formulations, but suffers from some drawbacks, including photo instability. To mitigate this critical issue, the use of octocrylene as a stabilizer is a common approach in these products. However, octocrylene has been recently demonstrated to show potential phototoxicity. The aim of this work is to analyze the performance of a series of mycosporine-like amino acid (MAA)-inspired compounds to act as avobenzone stabilizers as an alternative to octocrylene. Different avobenzone/MAA analogue combinations included in galenic formulations were followed under increasing doses of solar-simulated UV radiation. Some of the synthetic MAA analogues analyzed were able to increase by up to two times the UV dose required for 50% of avobenzone photobleaching. We propose some of these MAA analogues as new candidates to act as avobenzone-stabilizing compounds in addition to their UV absorbance and antioxidant properties, together with a facile synthesis.

Effect of UV pretreatment on the source control of floR during subsequent biotreatment of florfenicol wastewater.

UV photolysis has been recommended as an alternative pretreatment method for the elimination of antibacterial activity of antibiotics against the indicator strain, but the pretreated antibiotic intermediates might not lose their potential to induce antibiotic resistance genes (ARGs) proliferation during subsequent biotreatment processes. The presence of florfenicol (FLO) in wastewater seriously inhibits the metabolic performance of anaerobic sludge microorganisms, especially the positive correlation between UV irradiation doses and ATP content, while it did not significantly affect the organics utilization ability and protein biosynthetic process of aerobic microorganisms. After sufficient UV pretreatment, the relative abundances of floR from genomic or plasmid DNA in subsequent aerobic and anaerobic biotreatment processes both decreased by two orders of magnitude, maintained at the level of the groups without FLO selective pressure. Meanwhile, the abundances of floR under anaerobic condition were always lower than that under aerobic condition, suggesting that anaerobic biotreatment systems might be more suitable for the effective control of target ARGs. The higher abundance of floR in plasmid DNA than in genome also indicated that the potential transmission risk of mobile ARGs should not be ignored. In addition, the relative abundance of intI1 was positively correlated with floR in its corresponding genomic or plasmid DNA (p < 0.05), which also increased the potential horizontal transfer risk of target ARGs. This study provides new insights into the effect of preferential UV photolysis as a pretreatment method for the enhancement of metabolic performance and source control of target ARGs in subsequent biotreatment processes. KEY POINTS: • Sufficient UV photolytic pretreatment efficiently controlled the abundance of floR • A synchronous decrease in abundance of intI1 reduced the risk of horizontal transfer • An appreciable abundance of floR in plasmid DNA was a potential source of total ARGs.

Inactivation effect and kinetic analysis of multi-band ultraviolet LED combined with Ag/N modified magnetic TiO2 on microorganisms in ballast water

The invasion of harmful aquatic organisms from ship ballast water is a serious threat to the marine ecosystem. However, the existing treatment technology has the defects of high energy consumption, secondary pollution and easy revival of organisms, etc. How to inactivate the microorganisms in ballast water efficiently is always a difficult challenge. In this study, the inactivation of Karenia mikimotoi and Escherichia coli under UVA/UVCLED photocatalytic system (UVA/UVCLED + Ag/N-Fe3O4-SiO2-TiO2) was investigated using Ag-modified and N-modified magnetic TiO2 nanomaterials. The results showed that the ability of 1.5 % Ag with 3 % N dual-modified TiO2 to enhance the system's biologically logarithmic inactivation rate was 4–5 times higher than that of conventional unmodified TiO2. The Ag/N-modified magnetic TiO2 had the best photocatalytic activity at a dosage of 500 mg/L. After 6 cycles of use, the inactivation efficiency in combination with UVA/UVCLED only decreased by 8.76 % compared with the initial use, and the recycling rate was still up to 95.75 %. Meanwhile, the scanning electron microscope showed that the photocatalyst itself only had some minor changes after 6 cycles, which confirmed the fact that the photocatalytic removal rate (higher than 91.24 %) could still be maintained at a high level. The UVA/UVCLED photocatalytic system significantly inhibited the scavenging ability of superoxide dismutase (SOD) on reactive oxygen species (ROS), enhanced the toxic effect of ROS on cells, and ultimately accelerated the process of apoptosis and inhibited biological resurrection. In addition, this study verified the inactivation kinetics of the target microorganisms using Chick-Watson, Hom and Biphasic models, and found that all individuals in the same population differed in their tolerance to UV radiation, and some of them absorbed more than a threshold dose of UV radiation before showing inactivation responses. The Biphasic model (R2: 0.99571–0.99926) can better simulate the nonlinear changes exhibited during the inactivation process and is more applicable to the actual disinfection situation of UVA/UVCLED photocatalytic systems. The UVA/UVCLED + Ag/N-Fe3O4-SiO2-TiO2 photocatalytic technology developed in this study, as a novel oxidation process, reduces energy consumption while effectively inhibiting the reanimation of organisms, and exhibits a strong potential for application in the fields of restoring the environment of water bodies and blocking the spread of pathogens.

Применение ультрафиолета для предпосевной обработкой семян

Modern methods of pre-sowing seed treatment disinfect seeds, increase yield and plant resistance to adverse environmental factors, and stimulate plant immunity. Among the methods of electromagnetic impact on bioobjects, irradiation of seeds with ultraviolet light is simple, energy-efficient, economically beneficial and environmentally safe. The research aimed to study the effect of UV irradiation for pre-sowing treatment of thuja seeds and empirically determine the effective dose of UV irradiation. To maintain the required UV irradiation dose, the authors developed a digital control system on ATMEGA128A microcontroller (ATMEL). The working area of a 12 × 12 UV matrix consisting of 200 UV LEDs was 144 cm2 . The distance from the UV LEDs to the irradiated seeds was about 2 cm. The UV dose of the matrix was controlled by monitoring the voltage drop on the NSL-19M51 photoresistors. The irradiance of the LEDs in the UV-A (UV-A) zone corresponded to 98%. In each series, 100 seeds of thuja occidentalis were irradiated; the experiments were repeated four times. The authors studied UV irradiation doses of 2 kJ/m2 , 3 kJ/m2 , and 4 kJ/m2 . Seeds of thuja occidentalis without UV irradiation treatment were used as a control. The effective dose of UV-irradiation of seeds was determined empirically. The determined UV irradiation dose of 2 kJ/m2 is able to increase seed germination energy by 12.8% as compared to the control. Statistical processing of empirical data showed satisfactory accuracy of the conducted experiments. The accuracy index of the experiment amounted to P=1.76%±0.65%, for the control (without UV irradiation) - P=1.33±0.47%.

Increasing the shelf life of packaged bakery products by their processing of broadband optical radiation of a pulsed xenon lamp

Pulsed xenon lamps generating a wide spectrum of radiation of the megawatt range are sources of a new generation of biocidal radiation, which shows potential in the food industry. The article presents the results of studies of the efficiency of pulsed xenon lamp radiation in relation to antifungal treatment of bakery products in sealed plastic packaging in order to increase their shelf life. The object of research was commercial samples of bakery products packed in polypropylene film. The samples were processed by radiation from a pulsed xenon lamp with power of 300 watts. It is shown that irradiation of bakery products samples in the mode with an integral fluence of broadband optical radiation of 10 J/cm2 and a dose of short-wave UV radiation of 0.6 J/cm2 makes it possible to increase their shelf life several times (on average 2 times for most types of samples) compared with untreated samples. General conclusion: optical radiation of a pulsed xenon lamp has a pronounced antifungal effect and is able to inhibit the development of mold fungi on bakery products, even when they are processed in packaged form. The obtained results can be used in the development of equipment of antifungal treatment of bakery products.

Comparative assessment of UV-C radiation and non-thermal plasma for inactivation of foodborne fungal spores suspension in vitro.

Fungal contamination poses a persistent challenge to industries, particularly in food, healthcare, and clinical sectors, due to the remarkable resilience of fungi in withstanding conventional control methods. In this context, our research delves into the comparative efficacy of UV radiation and non-thermal plasma (NTP) on key foodborne fungal contaminants - Alternaria alternata, Aspergillus niger, Fusarium culmorum, and Fusarium graminearum. The study examined the impact of varying doses of UV radiation on the asexual spores of all mentioned fungal strains. Simultaneously, the study compared the effects of UV radiation and NTP on the metabolic activity of cells after spore germination and their subsequent germination ability. The results revealed that UV-C radiation (254 nm) did not significantly suppress the metabolic activity of cells after spore germination. In contrast, NTP exhibited almost 100% effectiveness on both selected spores and their subsequent germination, except for A. niger. In the case of A. niger, the effectiveness of UV-C and NTP was nearly comparable, showing only a 35% decrease in metabolic activity after 48 hours of germination, while the other strains (A. alternata, F. culmorum, F. graminearum) exhibited a reduction of more than 95%. SEM images illustrate the morphological changes in structure of all tested spores after both treatments. This study addresses a crucial gap in existing literature, offering insights into the adaptation possibilities of treated cells and emphasizing the importance of considering exposure duration and nutrient conditions (introduction of fresh medium). The results highlighted the promising antimicrobial potential of NTP, especially for filamentous fungi, paving the way for enhanced sanitation processes with diverse applications.

LED ДЖЕРЕЛА УЛЬТРАФІОЛЕТОВОГО ВИПРОМІНЮВАННЯ: МЕТОДИЧНЕ ТА ПРИЛАДОВЕ ЗАБЕЗПЕЧЕННЯ З УРАХУВАННЯМ ГАРМОНІЗАЦІЇ ЗАКОНОДАВСТВА ЄС ТА УКРАЇНИ

One of the effective means of disinfecting premises is its irradiation with ultraviolet bactericidal radiation (UVBV), which is in the UV-C region (200 nm - 280 nm) and for mercury lamps has a radiation peak at a wavelength of 254 nm. However, UVBV should be used competently and with appropriate caution in terms of its intensity and safety, avoiding risks of damage to human skin and eyes. Therefore, UVBV is used indoors, mainly in the absence of a person. But when using sources of this type of optical radiation in the presence of a person, proper attention should be paid to controlling the intensity of UVBV and the time of its exposure. At the same time, it should be noted that the active processes of harmonization of the legislation of the EU and Ukraine require the modernization of the regulatory and methodological base for the measurement and hygienic assessment of ultraviolet radiation in the production environment and in the environment, significantly expanding the possibilities of using UVB sources, including in the presence of humans. Therefore, the purpose of the study is to create the basis for appropriate methodological recommendations for the use of bactericidal ultraviolet monochrome LED sources for disinfection of air and surfaces in rooms, as well as the formulation of appropriate requirements for UV radiometers, which should ensure control of the technical parameters of the mentioned ultraviolet monochrome LED sources. As a result of the research, scientific principles were proposed for the instrumental and methodical control of the safe use of bactericidal ultraviolet monochrome LED sources for the improvement of air and surfaces in premises of various purposes, taking into account the requirements of the legislation of Ukraine and the EU. The technical characteristics of the available UVBV LED sources were analyzed, based on which the medical and technical requirements for UV radiometers were formulated, which should ensure control of the intensity and actinic dose of UV radiation in accordance with the requirements of DSTU EN 62471:2017 "Safety of photobiological lamps and lamp systems (EN 62471:2008 , IDT; IES 62471:2006, MOD)". Design approaches to the formation of the spectral range of RG sensitivity by using appropriate light filters, including for the blue light range (380-480 nm), have been determined. A technique for correcting the spectral characteristic of the RG sensitivity is proposed, which contributes to the reduction of the intensity measurement error created by different LED sources.

Gene-environment interactions and risk of pediatric-onset multiple sclerosis associated with time spent outdoors

BackgroundOur previous study identified a significant association between lower time spent outdoors, as a proxy of sun exposure, and a higher risk of pediatric-onset multiple sclerosis (POMS). UV radiation modulates the expression of several genes, but it is unknown whether these genes modify the effect of sun exposure on POMS risk. MethodsIn an age- and sex-matched case-control study, we evaluated the additive and multiplicative interactions between time spent outdoors and genetic non-HLA risk variants for developing POMS within the metabolic pathways of UV radiation, including CD28(rs6435203), CD86(rs9282641), and NFkB1(rs7665090) and the top two HLA risk factors (presence of DRB1×15 and absence of A*02). ResultsIn an adjusted model (332 POMS cases, 534 healthy controls), greater time compared to <30 min/day spent outdoors during the prior summer and higher UV radiation dose were associated with decreased odds of POMS (OR 0.66, 95% CI 0.56–0.78, p < 0.001; OR 0.78, 95 % CI 0.62–0.98, p = 0.04, respectively). No significant additive or multiplicative interactions were found between risk factors. ConclusionsThe exploration of gene-environment interactions in the risk of developing MS can unravel the underlying mechanisms involved. Although we do not have evidence that our candidate genes contribute to interactions, other genes may.

Degradation of Mechanical Properties of A-PET Films after UV Aging.

In 2018, the European Commission adopted the European Strategy for Plastics in a Circular Economy, which outlines key actions to reduce the negative impact of plastic pollution. The strategy aims to expand plastic recycling capacity and increase the proportion of recycled materials in plastic products and packaging. Using recycled plastic can save 50-60% energy compared to virgin plastic. Recycled PET can be used in the production of A-PET films, which are predominantly used in thermo-vacuum forming for food packaging. Storage conditions can influence the mechanical properties of polymer materials. This work presents changes in the mechanical properties of A-PET films after UV irradiation. An experimental investigation of the UV aging of A-PET films was conducted in a UV aging chamber. The specimens were exposed to a UV radiation dose rate of 2.45 W/m2 for 1, 2, 4, 8, 16, 24, 32, and 40 h. UV measurements were also taken on a sunny day to compare the acceleration of UV irradiation in the UV aging chamber. Mechanical tensile tests were performed on two different three-layer A-PET films (100% virgin and 50% recycled). The tensile strength and relative elongation of the A-PET films were determined, and the work required to break the film was calculated. The total consumed work was divided into the work needed for elastic and plastic deformations. A study of the UV aging of A-PET films confirmed a significant effect on the films, including a loss of plasticity even after brief exposure to solar irradiance. The results of the puncture impact test further confirmed the deterioration of the mechanical properties of A-PET material due to exposure to UV radiation, with a greater effect observed for the recycled material.

Capsule Dosimeters for Ultraviolet Radiation Measurements on Coral Reefs and in Seawater.

This work reports on the new chemical dosimeters for UV radiation dose measurements on coral reefs and in seawater. The proposed dosimeters can measure the actual dose of UV radiation, which consists of 95% UVA and 5% UVB radiation, unlike the currently-used radiometers in marine and ocean waters that measure the dose of UVA and UVB radiation separately. The dosimeters are composed of water, poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F-127) as a gel matrix, and 2,3,5-triphenyltetrazolium chloride (TTC) as a UV radiation-sensitive compound. In the work, the dosimeters were characterised in terms of their response to the dose of UV radiation depending on the TTC concentration and the irradiation and storage conditions of the dosimeters. The stability of the dosimeters over time was also examined. The obtained results indicate that the TTC-Pluronic F-127 dosimeters can be used to measure absorbed doses of UV radiation in the saltwater environment. The developed dosimeters with a concentration of 0.1% TTC can be used up to 5 J/cm2, which predisposes them to UV radiation measurements at a depth of more than 10 m in sea and ocean waters in 10-min intervals during all months throughout the year.

Multicolor photochromic material with dual protection of anti-counterfeiting and waterproofing

Optical information storage materials with dual protectiveness of anti-counterfeiting and waterproofing are critical to store information and improve paper utilization in a safe and accurate way. A novel multifunctional material with efficient photo-responsiveness and hydrophobicity was herein developed. Wherein, a system of silver ion (Ag+)/polyoxometalates/polymer was creatively formed as a photochromic layer, achieving different color variations by different contents of Ag+ and UV irradiation doses. This functional surface can maintain colored state for a long time in indoor environments, which is favorable to long-term information storage. It can be quickly blenched within 20 min under a hydrogen peroxide-containing atmosphere, achieving controllability of fading time. In addition, a multifunctional transparent coating formed by PDMS and fine particles composed of ytterbium compound and silica was applied on photochromic layer. This coating rapidly generates dazzling green light under infrared radiation, laying a foundation for the safe transmission of information. Its microstructures effectively capture air in gaps and low surface energy avoids wetting of water, achieving excellent hydrophobicity with a surface contact angle of 152°. In a word, this elaborately designed strategy for information storage via photochromism and dual protection shows enormous application potentials in optical information storage and encryption.

Microbial Inhibition by UV Radiation Combined with Nisin and Shelf-Life Extension of Tangerine Juice during Refrigerated Storage.

This study evaluated the efficiency of UV radiation doses (4.68-149.76 J/cm2) and nisin (50-200 ppm) and their combination in comparison with thermal pasteurization on the microbial inhibition kinetics and physicochemical properties of tangerine juice. It was noted that UV-149.76 J/cm2 and nisin (NS) at 200 ppm in conjunction exhibited the highest log reduction in spoilage and pathogenic microbes including Escherichia coli, Lactiplantibacillus plantarum, and Saccharomyces cerevisiae, yeast and molds, and total plate count in tangerine juice. Additionally, the first-order kinetic model provides a better fit for spoilage and pathogenic strains compared with the zero-order model (higher coefficient of determination, R2), particularly for E. coli. UV and NS showed insignificant effects (p > 0.05) on pH, TSS, and TA values compared with pasteurization. However, there were notable differences observed in color analysis, total phenolic compound, total flavonoid content, vitamin C, carotenoid content, and antioxidant activity using DPPH and FRAP assays. The optimized UV + NS samples were subjected to refrigerated storage for 21 days. The results revealed that during the entire storage period, the pH values and the TSS values slightly decreased, and the TA values increased in the treated samples. The UV + NS treatment insignificantly impacted the color properties. The total phenolic, total flavonoid, and carotenoid contents, and vitamin C decreased over time for all sample treatments, whereas the antioxidant properties exhibited varying outcomes, compared with an untreated control and pasteurization. Therefore, UV radiation and nisin (UV-149.76 J/cm2 + NS-200 ppm) in combination could serve as a viable alternative to traditional heat pasteurization of fruit juice during cold storage.

The Role of Chromatin Assembly Factors in Induced Mutagenesis at Low Levels of DNA Damage.

The problem of low-dose irradiation has been discussed in the scientific literature for several decades, but it is impossible to come to a generally accepted conclusion about the presence of any specific features of low-dose irradiation in contrast to acute irradiation. We were interested in the effect of low doses of UV radiation on the physiological processes, including repair processes in cells of the yeast Saccharomyces cerevisiae, in contrast to high doses of radiation. Cells utilize excision repair and DNA damage tolerance pathways without significant delay of the cell cycle to address low levels of DNA damage (such as spontaneous base lesions). For genotoxic agents, there is a dose threshold below which checkpoint activation is minimal despite the measurable activity of the DNA repair pathways. Here we report that at ultra-low levels of DNA damage, the role of the error-free branch of post-replicative repair in protection against induced mutagenesis is key. However, with an increase in the levels of DNA damage, the role of the error-free repair branch is rapidly decreasing. We demonstrate that with an increase in the amount of DNA damage from ultra-small to high, asf1Δ-specific mutagenesis decreases catastrophically. A similar dependence is observed for mutants of gene-encoding subunits of the NuB4 complex. Elevated levels of dNTPs caused by the inactivation of the SML1 gene are responsible for high spontaneous reparative mutagenesis. The Rad53 kinase plays a key role in reparative UV mutagenesis at high doses, as well as in spontaneous repair mutagenesis at ultra-low DNA damage levels.

Effect of Low-Dose Line-Spectrum and Full-Spectrum UV on Major Humoral Components of Human Blood.

Ultraviolet blood irradiation (UVBI) is an alternative approach to the treatment of infectious diseases of various pathogeneses. Recently, UVBI has attracted particular interest as a new immunomodulatory method. Experimental studies available in the literature demonstrate the absence of precise mechanisms of the effect of ultraviolet radiation (UV) on blood. Here, we investigated the effect of UV radiation of line-spectrum mercury lamp (doses up to 500 mJ/cm2) traditionally used in UVBI on the major humoral blood components: albumin, globulins and uric acid. Preliminary data on the effect of various doses of UV radiation of full-spectrum flash xenon lamp (doses up to 136 mJ/cm2), a new promising source for UVBI, on the major blood plasma protein, albumin, are presented. The research methodology included spectrofluorimetric analysis of the oxidative modification of proteins and analysis of the antioxidant activity of humoral blood components by chemiluminometry. The effect of UV radiation on albumin caused its oxidative modification and, accordingly, an impairment of the transport properties of the protein. At the same time, UV-modified albumin and γ-globulins acquired pronounced antioxidant properties compared to native samples. Uric acid mixed with albumin did not protect the protein against UV-induced oxidation. The flash full-spectrum UV qualitatively had the same effect on albumin as line-spectrum UV did, but an order of magnitude lower doses were required to achieve comparable effects. The suggested protocol can be used for selecting a safe individual dose for UV therapy.

Evaluation of the effectiveness of ultraviolet disinfection (254 nm) of aqueous solutions from phytopathogenic microorganisms

Relevance. Currently, greenhouse complexes use water for irrigation from open surface sources (ponds, lakes, rivers) and underground water from wells, adding a return (drainage) solution to it. At the same time, water from both open sources and drainage solution often becomes a source of emergence and spread of phytopathogenic infection in greenhouses, which brings economically significant crop losses. In this regard, the need to develop guaranteed methods and methods for the disinfection of drainage water and water from open sources is relevant. One of the methods of water disinfection is the use of ultraviolet irradiation, but for the effective use of irradiation, it is necessary to ensure the minimum effective UV dose. This UV dose is typical for each pathogen.Results. Work was carried out to experimentally establish doses of UV irradiation that allow complete inactivation of vegetative cells and spores of bacteria and fungi (Agrobacterium tumefaciens, Pythium debaryanum, Fusarium oxysporum, Verticillium dahliae, Phoma destructiva) in a solution prepared on the basis of distilled water. A dose of UV irradiation of 40 mJ/cm2 ensured complete inactivation of the bacterial pathogen, and a dose of 60 mJ/cm2 showed complete inactivation of the pathogens of the studied fungal infections.