Doses Of Ultraviolet Radiation Research Articles

Study of the Sensor Properties of Ordered ZnO Nanorod Arrays for the Detection of UV Radiation

Zinc oxide is one of the most promising materials used to create devices in the ultraviolet (UV) range. In this article, we study the sensor properties of ordered ZnO nanorod arrays grown by chemical vapor deposition. The possibility of their use as an indicator of UV radiation to control the dose of UV radiation, both from natural and artificial light sources, is assessed. The X-ray diffraction, Raman spectroscopy (RS), and cathodoluminescence (CL) data demonstrate the high quality of nanorods. Based on the ZnO nanorod array, a sensor prototype was fabricated based on the change in ZnO conductivity under the UV irradiation. A compari-son of the response of such a sensor with the readings of a UV radiometer showed a high correlation.

PD03 Afamelanotide reduces the ultraviolet radiation erythemal response soon after application in healthy volunteers with skin phototypes II–III

Abstract Afamelanotide is a potent α-melanocyte stimulating hormone analogue that binds to the melanocortin 1 receptor and, over time, promotes tanning, conferring systemic photoprotection. Afamelanotide also has antioxidant properties and may promote repair of ultraviolet (UV) radiation (UVR)-induced DNA damage. The objectives of this study were to examine the short-term impact of afamelanotide on DNA damage repair mechanisms, UVR erythema and melanogenic responses in healthy human skin following exposure to UVR. Healthy men and women (n = 10) volunteers aged 27–43 years (median 34) of skin phototypes II–III were recruited. Reflectance spectrophotometry was performed on six body sites (photoexposed and photoprotected) to assess skin pigmentation, and then a geometric series of erythemally weighted doses (7–80 mJ cm−2) of broadband UVB (∼60% UVB, 40% UVA; Philips TL12) was applied to unexposed upper buttock skin. After 24 h, the minimal erythema dose (MED) was assessed and erythema intensity (CIE a*) was measured at each dose site. A subcutaneous implant of afamelanotide 16 mg was administered; 5 days later, the same UVR dose series was applied to unexposed contralateral upper buttock skin. After 24 h, the MED was assessed and repeat skin reflectance measurements were performed. The overall UVR–erythema dose response (area under curve) showed a significant decrease post-afamelanotide (mean 3.5 vs. 2.7; P = 0.018). There was an apparent increase in the median MED post-afamelanotide (24.5 vs. 29.9 mJ cm−2; not statistically significant). Reflectance measurements showed skin lightness (CIE L*) significantly decreased at only one site (central forehead, from 63.0 to 61.0; P = 0.015), while determination of melanin density by reflectance at 420 and 400 nm showed a statistically significant increase in density at all sites except the right abdomen, with a mean overall increase from 2.5% to 2.9% (P = 0.001). Our results indicate that afamelanotide reduces the overall UVR–erythema dose response in healthy human skin shortly after administration, with a small increase in melanogenesis, suggesting other nonmelanogenic properties of this agent contribute to the erythema protection. Further investigation will examine whether enhanced repair of UVR-induced DNA damage plays a role. Funding sources: research sponsored by CLINUVEL (UK) Ltd.

Micromechanical modeling of the visco-hyperelastic–viscoplastic​ behavior and fracture of aged semicrystalline polymers

This work presents a micromechanical-based visco-hyperelastic–viscoplastic constitutive model for low-density polyethylene (LDPE) films subjected to accelerated ultraviolet (UV) aging. The model captures the evolution of the mechanical and fracture properties of the material. Our proposed framework assumes that the semicrystalline polymer’s macromechanical behavior is the sum of the intermolecular and macromolecular network contributions. The intermolecular part of the model follows a nonlinear composite mixture rule, combining the contribution of the crystalline and amorphous phases, each represented rheologically by a linear elastic spring in series with a nonlinear viscous dashpot. The rheological representation of the macromolecular network consists of a series of two Langevin springs capturing deformation-induced conformation change and interatomic bond deformation between Kuhn segments, as well as a viscous dashpot for chain relaxation. We have developed a novel framework that reformulates the eight chain model to include the energy densities associated with both conformation change and interatomic bond deformation, providing a more accurate description of macromolecular network mechanical and fracture behavior. The aging of semicrystalline polymers results from two competing mechanisms: oxidation-induced strengthening resulting from chemicrystallization and crosslinking, and oxidation-induced softening resulting from chain scissions and chemicavitation. Our proposed model accurately captures the effect of UV aging on the mechanical behavior of the semicrystalline material. Additionally, we introduce the novel concept of a ”healthy network” to predict the evolution of the strain to fracture. The model accurately predicts the evolution of the mechanical behavior and elongation at break over a wide range of UV irradiation doses.

Ultraviolet radiation exposure in cannabis-growing facilities

Cannabis cultivation and processing is becoming an important industry in the United States and Canada. The industry employs over 400,000 workers in the United States and is growing rapidly. Both natural sunlight and artificial lamp-generated radiation are commonly used to grow cannabis plants. These optical sources can contain both visible and ultraviolet radiation (UVR) wavelengths, and overexposure to UVR is associated with negative health effects. The severity of these adverse health effects is governed by the specific wavelengths and exposed dose of UVR, yet worker exposure to UVR within cannabis-growing facilities has not been studied. In this study, worker exposure to UVR was assessed at five cannabis production facilities in Washington State, including indoor, outdoor, and shade house facilities. Lamp emission testing was performed at each facility and worker UVR exposures were measured for 87 work shifts. Observations of worker activities and use of personal protective equipment in association with UVR exposure measurements were recorded. For lamp emission measurements, at 3 feet from the center of the lamp, the average irradiances were 4.09 × 10−4, 6.95 × 10−8, 6.76 × 10−9, 3.96 × 10−9, and 1.98 × 10−9 effective W/cm2 for germicidal lamps, metal halide lamps, high-pressure sodium lamps, fluorescent lamps, and light emitting diodes, respectively. The average measured UVR exposure was 2.91 × 10−3 effective J/cm2 (range: 1.54 × 10−6, 1.57 × 10−2 effective J/cm2). Thirty percent of the work shifts monitored exceeded the American Conference for Governmental Industrial Hygienists (ACGIH®) threshold limit value (TLV®) of 0.003 effective J/cm2. Exposures were highest for workers who spent all or part of the work shift outdoors, and solar radiation was the primary source of worker UVR exposure for most of the work shifts that exceeded the TLVs. Outdoor workers can reduce UVR exposure by applying sunscreen and wearing appropriate personal protective equipment. Although the artificial lighting used in the cannabis production facilities included in this study did not contribute substantially to the measured UV exposures, in many cases the lamp emissions would generate theoretical exposures at 3 feet from the center of the lamp that would exceed the TLV. Therefore, employers should choose low UVR emitting lamps for indoor grow operations and should use engineering controls (e.g., door-interlocks to de-energize lamps) to prevent worker exposure to UVR from germicidal lamps.

Very high erythemal doses of ultraviolet radiation around solar noon measured in Arica, northern Chile

News media and meteorological bulletins generally report on the ultraviolet index (UVI) to prevent overexposure to the sun. However, this information does not reflect the accumulated damage to the skin induced by the total amount of UVR (ultraviolet radiation) accumulated over time, known as erythemal dose (ED). This study analyzed the UVI and ED measured at ±30 and ±60 minutes around solar noon (SN) in Arica, North of Chile. The results show that SN ED exceeded the Minimum Erythema Dose (MED) for all the skin types. During the summer, shorts exposures to sunlight for up to 1 hour may result in sun exposure up to 10 times greater than the acceptable occupational safe limit for unprotected human skin.

Estimation of the Variance Components in TP53 mRNA Expression in the Rat Lens after in vivo Exposure to Ultraviolet Radiation B

Introduction: The aim of this study was to investigate the variance components in TP53 mRNA expression after in vivo exposure to double threshold dose of ultraviolet radiation B (UVR-B). Methods: Twelve six-week-old female albino Sprague-Dawley rats were exposed to double threshold dose (8 kJ/m²) of UVR-B unilaterally and sacrificed at 1, 3, 8, and 24 h after exposure. Lenses were enucleated, and TP53 mRNA expression was detected by qRT-PCR. Variance components for groups, animals, and measurements were estimated with analysis of variance. Results: The variance for groups is 0.15 rel.². The variance for animals is 0.29 rel.². The variance for measurements is 0.32 rel.². Conclusion: The variance for animals is in the same order as the variance for measurements. The reduction of the variance for measurements is needed in order to obtain the acceptable level of detection of the difference in TP53 mRNA expression and the reduction in sample size.

Abstract 2384: Quantitative phase imaging provides new insights into diverse morphologies in cell lines and their behavior in response to alternative cancer treatments

Abstract Quantitative phase imaging (QPI) through holographic time-lapse microscopy allows for non-invasive measurements of cell dry mass and the ability to track cells for long periods of time with minimal damage, making it most beneficial for research on cancer treatment. Research with this enhanced method of observation can help decipher various morphologies present in specific cell lines and show how each cell can respond differently to provided signals. In this assay, we studied N2a murine neuroblast differentiation in response to Retinoic acid, as well as the anticancerous activity of Saffron and UV in MDA-MB-468 breast carcinoma and HCT116 colon carcinoma cell lines. Cells were observed using Telight’s Q-Phase, a multimodal microscope that utilizes QPI holographic time-lapse technology with label-free monitoring. The cells were able to survive in optimum conditions for up to 96 hours without any appreciative loss of viability. With the emergence of phytochemicals being used as alternative cancer treatments, specific pigments in saffron have shown therapeutic effects against cancer tissues such as apoptosis and decreased carcinogen presence. A microanalysis of the effects of saffron on reducing the invasion potential, viability, and tumorigenicity of breast cancer cell lines was performed. QPI microscopy was performed on MDA-MB-468 human breast adenocarcinoma and HCT116 colon carcinoma cell lines treated with varying doses of saffron and ultraviolet radiation. Cell lines were observed under the microscope for 58-hour periods for changes in mass, movement, and replication. The quantitative data showed a reduction of projections from saffron treatment but did not show any significant reduction in cell movement over the 58-hours. These results were later confirmed through scratch wound and Boyden chamber assays. Similarly, when examining the process of N2a neuroblast differentiation, it was observed that cells do not move towards differentiation in a linear manner, but rather changed their direction and path several times before committing to their final phenotype. These types of observations are critical in understanding the biological processes behind differentiation and drug response and could not have been done without using the various quantitative and analysis tools provided by the QPI technology. Citation Format: Rida Khan, Meaghan McDonald, Albina Mikhaylova, Fatima K. Rehman. Quantitative phase imaging provides new insights into diverse morphologies in cell lines and their behavior in response to alternative cancer treatments [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2384.

Digitally measuring solar ultraviolet radiation in outdoor workers: A study protocol for establishing the use of electronic personal dosimeters in Portugal.

The rising incidence of skin cancer over the years has made it a significant public and occupational health issue. However, skin cancer is highly preventable, mainly through reduced exposure to solar ultraviolet radiation (UVR), which can be achieved by a variety of individual and collective protective measures and interventions. The relative risk associated with different patterns of exposure to solar UVR differs for the subtypes of keratinocyte cancers (KC). Specifically, whether the exposure is intermittent or continuous, and occurs in an occupational or leisure/recreational setting. The main aim of the study using this protocol is to contribute to raising public and policy awareness on solar UVR-inflicted occupational skin cancers in Lisbon. This will be achieved by performing direct measurements of the solar UVR dose received by outdoor workers using a digital platform. Results will likely contribute to further understanding the risk estimates for keratinocyte cancer estimations in this population. A prospective observational study will be conducted in Lisbon, Portugal. Personal electronic dosimeters (GENESIS-UV system) integrated with a digital platform will be used to assess occupational solar UVR doses of gardeners, masons, and gravediggers of the municipality of Lisbon. Two hundred and ten outdoor workers will be selected to wear the dosimeter for 1 month each, between April and October during their daily working hours. A digital web-based platform that offers private access to information through dashboard visualization will provide information for the outdoor workers and facilitate communication with the participants. The expected results of the overall proposal comprise the occupational solar UVR doses, expressed in standard erythemal dose (SEDs) per day of outdoor work for 7 months. Study data will provide outdoor workers with information on their personal solar UVR exposure during their working hours and an estimate of their risk of developing skin cancer. It is expected that the occupational solar UVR doses of the outdoor workers in Portugal will be above the threshold of 1 to 1.33 SED/day, due to the latitude of Lisbon and the nature of the occupations. The results prospectively should flow into the design of adequate prevention campaigns for skin cancer in outdoor workers.

Multiparametric Quantitative Analysis of Photodamage to Skin Using Optical Coherence Tomography.

Ultraviolet (UV) irradiation causes 90% of photodamage to skin and long-term exposure to UV irradiation is the largest threat to skin health. To study the mechanism of UV-induced photodamage and the repair of sunburnt skin, the key problem to solve is how to non-destructively and continuously evaluate UV-induced photodamage to skin. In this study, a method to quantitatively analyze the structural and tissue optical parameters of artificial skin (AS) using optical coherence tomography (OCT) was proposed as a way to non-destructively and continuously evaluate the effect of photodamage. AS surface roughness was achieved based on the characteristic peaks of the intensity signal of the OCT images, and this was the basis for quantifying AS cuticle thickness using Dijkstra's algorithm. Local texture features within the AS were obtained through the gray-level co-occurrence matrix method. A modified depth-resolved algorithm was used to quantify the 3D scattering coefficient distribution within AS based on a single-scattering model. A multiparameter assessment of AS photodamage was carried out, and the results were compared with the MTT experiment results and H&E staining. The results of the UV photodamage experiments showed that the cuticle of the photodamaged model was thicker (56.5%) and had greater surface roughness (14.4%) compared with the normal cultured AS. The angular second moment was greater and the correlation was smaller, which was in agreement with the results of the H&E staining microscopy. The angular second moment and correlation showed a good linear relationship with the UV irradiation dose, illustrating the potential of OCT in measuring internal structural damage. The tissue scattering coefficient of AS correlated well with the MTT results, which can be used to quantify the damage to the bioactivity. The experimental results also demonstrate the anti-photodamage efficacy of the vitamin C factor. Quantitative analysis of structural and tissue optical parameters of AS by OCT enables the non-destructive and continuous detection of AS photodamage in multiple dimensions.

The Retention of Vitamin D2 and 25-Hydroxyvitamin D2 in Pulse UV-Irradiated Dried Button Mushrooms (Agaricus bisporus) after 12 Months of Storage.

Fresh mushrooms exposed to ultraviolet (UV) radiation prior to drying generate high concentrations of vitamin D2. The aim of this study was to determine the retention of D vitamers in mushrooms that were pulse UV irradiated, then air dried, and stored for up to 12 months. Fresh button mushrooms (A. bisporus) were exposed to pulsed UV radiation (dose 200 mJ/cm2, peak of 17.5 W/cm2), air dried and vacuum sealed before being stored in the dark at room temperature. After storage, samples were freeze dried and quantified for D vitamers using triple quadrupole mass spectrometry. After 3, 6 and 12 months of storage, there was 100% (11.0 ± 0.8 µg/g dry weight (DW), 93% (10.1 ± 0.6 µg/g DW) and 58% (5.5 ± 0.6 µg/g DW) retention of vitamin D2 and 88% (0.14 ± 0.01 µg/g DW), 71% (0.11 ± 0.01 µg/g DW) and 68% (0.1 ± 0.01 µg/g DW) retention of 25-hydroxyvitamin D2 (25(OH)D2), respectively. Compared to the irradiated dried mushrooms that were not stored, the D vitamer concentration was statistically significantly lower (p < 0.05) at 6 and 12 months for 25(OH)D2 and at 12 months for vitamin D2. Sufficient vitamin D2 (99 µg) remained after 12 months storage to provide at least 100% of daily dietary vitamin D requirements in a 20 g serving.

UVBoost: An erythemal weighted ultraviolet radiation estimator based on a machine learning gradient boosting algorithm

This article presents UVBoost, an ultraviolet radiation (UVR) estimator based on a Supervised Machine Learning (SML) regression model powered by high precision calculations provided by a conventional Radiative Transfer Model (RTM). The proposed regression model takes UVR as a dependent variable, and the Solar Zenith Angle (SZA), Total Ozone Content (TOC), and Aerosol Optical Depth (AOD), as the independent predictive variables. UVBoost was developed to increase computational speed for conducting calculations with large databases, without sacrificing accuracy. Furthermore, this method employs a user-friendly code, which can be used by laymen or researchers in other areas. UVBoost can be employed to disseminate UVR data in different spatiotemporal scales, or for climatological projection studies on a global scale. UVBoost was developed by comparing seven regression SML tools via cross validation. Results were validated using non-parametric statistical tests. Of all the tested tools, the Categorical Boosting (CatBoost) method showed the best accuracy at the lowest computational cost. Two additional studies were carried out, one at the global scale, and another at the local scale, to compare the traditional RTM vs. the UVBoost results. The first study simulated a global UVR field (1°x1°) with 64,800 gridpoints. The differences between RTM and UVBoost were less than ±5% for approximately 95% of all points, except for high SZA datapoints. The computational speed of UVBoost surpassed that of the RTM by more than three orders of magnitude. The second study simulated the daily UVR at eight different locations on Earth. The results showed that the UVBoost was very efficient in simulating accumulated UVR doses during the day, with negligible differences (< ±3%), which means it can be used in studies on UVR and human health. In the future, UVBoost will include other geophysical parameters and be extended to other bands in the electromagnetic spectrum.

Application of electrical technologies to increase the productivity of cucumber in protected ground structures

The rationale for the need to improve greenhouse complexes using energy-saving technologies for growing vegetable products, including cucumber, is presented. The purpose of the work is to justify the use of modern electrical technologies in protected ground structures to increase the productivity of cucumber. Based on the objectives of the study, the following tasks were identified: analysis of the operating modes of electrical equipment to identify ways to increase its productivity and reduce energy costs in the production of cucumbers on protected lands, significantly increase the efficiency of pre-sowing treatment of cucumber seeds by developing a system for automatic stabilization of the ultraviolet radiation dose. Energy requirements are related to the strategic choice of producers in relation to the structure, greenhouse and climate equipment used, such as ventilation systems, cooling, heating, as well as cultivation and adaptation methods. The search for new and efficient electrical technologies is becoming an urgent research aimed at optimizing the entire technological cycle and all stages of obtaining a high and high-quality crop. Including: 3D light surveillance models affecting the angle of the roof of the greenhouse in the direction, as well as this approach allows the greenhouse to receive 25% more natural light in the winter months, saving up to 15% energy; two new sensors will be tested to measure the true photosynthesis of crops; existing LED lighting has achieved an energy efficiency increase of about 40% in both summer and winter.

Влияние свето-импульсной обработки семян рапса ярового на лабораторную всхожесть и семенную инфекцию

The article presents the results of research on determining the impact of light pulsed ultraviolet radiation of "Ecosvet-1" device with different intensities (4, 8, 16, and 32 kJ/m2) on laboratory germinating ability of spring rapeseed variety Tavrion and its infestation by pathogenic microorganisms. The experiment was conducted at V.S. Pustovoit All-Russian Research Institute of Oil Crops in 2022. We determined the laboratory germination of seeds of rapeseed according to State Standard 12038-84 in Petri dishes in a humidity chamber, and the infestation by the diseases – according to State Standard 12044-93. Laboratory germination of rapeseed seeds in the control was 63.0%. The cause of the germination decrease was affection by fungi of the genera Alternaria Nees and Fusarium sp. Link, as well as by bacteria of the genera Pseudomonas Migula and Xanthomonas Dowson. As a result of the treatment of rapeseed seeds with a noninvasive polychromatic light pulse, there was an increase in laboratory germination by 6-16 % compared to the control due to a decrease in seed infection. According to the obtained data, the best result in the experiment showed the variant with a specific dose of ultraviolet radiation (SD UV) of 8 kJ/m2. Laboratory germination of seeds in this variant was 79.0%. All seedlings from normally germinated seeds were healthy. The prevalence of Alternaria blight was 2 times lower on non-germinated seeds than on the control, Fusarium blight – 3 times lower, and bacterial blight – 1.5 times lower. The obtained data suggest that this method is promising for the presowing disinfection of rapeseed seeds from pathogenic microflora.

Sun protection and occupation: Current developments and perspectives for prevention of occupational skin cancer.

A substantial proportion of all reported occupational illnesses are constituted by skin cancer, making this disease a serious public health issue. Solar ultra-violet radiation (UVR) exposure is the most significant external factor in the development of skin cancer, for which the broad occupational category of outdoor workers has already been identified as high-risk group. Sun protection by deploying adequate technical, organizational, and person-related measures has to be understood as a functional aspect of workplace safety. To prevent skin cancers brought on by-typically cumulative-solar UVR exposure, outdoor workers must considerably lower their occupationally acquired solar UVR doses. Estimating cumulative sun exposure in outdoor workers requires consideration of the level of solar UVR exposure, the tasks to be done in the sun, and the employees' solar UVR preventive measures. Recent studies have highlighted the necessity for measures to enhance outdoor workers' sun protection behavior. In the coming decades, occupational dermatology is expected to pay increasing attention to sun protection at work. Also, the field of dermato-oncology will likely be concerned with sky-rocketing incidences of occupational skin cancers. The complete range of available alternatives should be utilized in terms of preventive actions, which seems pivotal to handle the present and future challenges in a purposeful manner. This will almost definitely only be possible if politicians' support is effectively combined with communal and individual preventive actions in order to spur long-term transformation.

Sustainable development of factory aquaculture through automation of ultraviolet parasiticide for the prevention and control of cryptocaryoniasis.

Cryptocaryon irritans infestations on marine teleosts are a considerable burden on factory mariculture. Ultraviolet (UV) light can kill C. irritans under laboratory conditions. However, a rational method for using UV in factory aquaculture to control cryptocaryoniasis has not been developed. This study focused on evaluating the killing effect of UV on protomonts and tomonts of C. irritans and established an automatic UV parasiticide device for the prevention and control of cryptocaryoniasis in marine teleosts. The survival rate of protomonts and tomonts decreased with an increase in the UV irradiation dose. All the protomonts and tomonts died within 14 and 24 min, respectively. The lowest UV lethal doses of protomonts and tomonts of C. irritans were 2.0 × 106 and 3.5 × 106 μWs cm-2 , respectively. Exposure of protomonts and tomonts to lethal doses of UV radiation led to shrinkage and severe dissolution of the protoplasm, causing abnormal development of cells. The survival rate of artificially infected Larimichthys crocea (treatment group, group A) was 83.33% at the end of the test (day 14) after disinfection using the automatic UV parasiticide device, whereas that of the control group (group C) was 90.00% (p < 0.05). However, all artificially infected L. crocea without disinfection using the automatic UV parasiticide device (untreated group, group B) died on day 8. The automation of traditional physical methods conforms to the sustainable development of aquaculture and provides a theoretical reference for the prevention and control of cryptocaryoniasis in mariculture. © 2022 Society of Chemical Industry.

Strategies for Improved Wettability of Polyetheretherketone (PEEK) Polymers by Non-Equilibrium Plasma Treatment

Polyetheretherketone (PEEK) is the material of choice in several applications ranging from the automotive industry to medicine, but the surface properties are usually not adequate. A standard method for tailoring surface properties is the application of gaseous plasma. The surface finish depends enormously on the processing parameters. This article presents a review of strategies adapted for improved wettability and adhesion of PEEK. The kinetics of positively charged ions, neutral reactive plasma species, and vacuum ultraviolet radiation on the surface finish are analyzed, and synergies are stressed where appropriate. The reviewed articles are critically assessed regarding the plasma and surface kinetics, and the surface mechanisms are illustrated. The directions for obtaining optimal surface finish are provided together with the scientific explanation of the limitations of various approaches. Super-hydrophilic surface finish is achievable by treatment with a large dose of vacuum ultraviolet radiation in the presence of oxidizing gas. Bombardment with positively charged ions of kinetic energy between about 100 and 1000 eV also enable high wettability, but one should be aware of excessive heating when using the ions.

Influence of germicidal ultraviolet radiation UV-C on the quality of Apiaceae spices seeds

BackgroundSpices are susceptible to surface microbial contamination. Countries’ ban on ethylene oxide fumigation due to possible residual toxicity encouraged the usage of irradiation. Surface sterilization with low doses of ultraviolet radiation has been extensively researched as a safe, eco-friendly, and fast route. This study examines the quality of Apiaceae spices for consumption, including anise, fennel, caraway, and cumin, in response to germicidal ultraviolet radiation using a developed sterilization unit.MethodsThe influence of UV-C (254 nm, 10.5 mW/cm2) on the fungal and microbial count, germination percentage, respiration rate, phenolic content, essential oil, and the activity of antioxidant enzymes was investigated at exposure durations of 0–45 min in increments of 5 min. The treated seeds were packed in polyethylene bags in a naturally aerated storage room for 30 days before the inspection.ResultsThe obtained data showed that UV-C stimulated seeds germination and increased respiration rate for all studied types. The 25 min of exposure exhibited the highest significant values compared to the control, considered a good indicator of seed vigor. In addition, UV-C exposure between 20 and 35 min promoted the accumulation of phenolic compounds and increased the oil content as a defense mechanism against radiation. Conversely, higher exposure to UV-C led to a significant reduction in phenolic and oil contents. Furthermore, the exposure to UV-C radiation enhanced the activity of antioxidant enzymes in terms of peroxidase and catalase, which progressively increased with increasing exposure durations, reached their peak at 25–30 min, and subsequently declined with extended exposure time was extended. In a similar pattern, exposure to UV-C radiation increased polyphenol oxidase activity to its highest level at 25 min, owing to the development of antioxidant protective mechanisms against oxidative stress.ConclusionUV-C irradiation in the range of 25–30 min is the most appropriate pretreatment to maintain the vitality of the examined seeds.Graphical

UV Radiation Exposure of Outdoor Workers in Antarctica.

The Antarctic region is a place of increasing interest. A growing number of personnel are working outdoors in extreme environmental conditions. They receive significant exposure to solar ultraviolet radiation (UVR) and are thereby at increased risk of adverse consequences. The aim of this study was to evaluate the UVR dose received by the outdoor workers at the Bulgarian Antarctic Base. Ten Caucasian healthy subjects, 8 males and 2 females with a mean age of 38 years (29-51) were enrolled. Of them, 5 were scientists and 5 were logistic workers. We measured the accumulated daily dose of UVR assessed by standard erythemal dose (SED) in the two groups. All subjects wore personal dosimeters located near the face-he only noncovered skin area. The dosimeters were factory calibrated for use in the Antarctic region. No statistical difference (P = 0.441) could be revealed between the SEDs in the two groups. The maximum UVR dose detected in a single day was 67.9 SEDs, and the highest cumulative dose was 548.03 SEDs. Study results are showing extreme measurements of UVR received by the members of the expeditions. We suggest meticulous UV protection for outdoor workers.

Role of Rapamycin and 3-MA in oxidative damage of HLECs caused by two doses of UVB radiation

BackgroundThis study compared the role of autophagy regulators Rapamycin and 3-MA in oxidative damage and apoptosis of human lens epithelial cells (HLECs) caused by two doses of Ultraviolet Radiation B (UVB). MethodsHLECs were irradiated with UVB, and two doses of UVB damage models were constructed. After treatment with autophagy regulators, cell damage tests such as CCK-8, LDH activity, and Ros detection were performed. Western blotting was used to detect the levels of autophagy-related proteins and apoptosis-related proteins. Quantitative real-time PCR (RT-qPCR) was used to detect the mRNA leve of secondary antioxidant enzymes.Flow cytometry was used to examine cell viability and apoptosis. Finally, the proportion of autophagy and apoptosis was observed by electron microscope. ResultsAutophagy inhibitor 3-MA promoted oxidative damage and apoptosis of HLECs at low doses of UVB (5 mJ/cm2), which corresponds to 1.3 ​h of exposure to sunlight in human eyes. Under the high dose of UVB (50mJ/cm2), which is equivalent to 13 ​h of exposure to sunlight in human eyes, the autophagy inducer Rapamycin caused more extensive oxidative damage and apoptosis of HLECs. 3-MA was able to reduce this damage, indicating that moderate autophagy is necessary for HLECs to cope with mild oxidative stress. For high dose UVB-induced oxidative stress, the use of 3-MA inhibiting autophagy is more beneficial to reduce cell damage and apoptosis. The mechanisms include degradation of damaged organelles, regulation of the expression of antioxidant enzymes HO-1, NQO1, GCS and regulation of apoptosis-related proteins. ConclusionsAutophagy played different roles in HLECs oxidative stress induced by two doses of UVB. It provides new ideas for reducing oxidative damage and apoptosis of HLECs to prevent or delay the progression of age-related cataract (ARC).

Quantification of Urinary Thymidine Dimers in Volunteers After Ultraviolet Radiation Using a New UPLC-MS/MS-based Method.

Solar ultraviolet radiation (UVR) is a carcinogen and irradiation of the skin results in DNA damage. Cyclobutane pyrimidine dimers (CPDs), including thymidine dimers, are among the most frequent forms of DNA damage. When CPDs are formed, the nucleotide excision repair system is activated and CPDs are excreted in the urine. Here, we developed a mass spectrometry-based method to quantify thymidine dimers in the urine and tested the method on a small group of volunteers after whole-body UVR exposure. Years of research resulted in a method based on the "dilute-and-shoot" principle and ultra-performance liquid chromatography (UPLC) coupled to mass spectrometry. The whole body of each of eight healthy volunteers was exposed to 1.5-2.0 standard erythema doses (SEDs) of UVR for 3 consecutive days. Morning urine was collected on Day 1 (before irradiation) and on the following 7-9 days. Prior to analysis, sample preparation consisted of a simple dilution. A tandem quadrupole mass spectrometer coupled to UPLC was used for quantitative analysis in the multiple reaction monitoring mode. After 3 consecutive days of 1.5-2 SEDs, the highest level of thymidine dimer excretion occurred on Day 6 (0.7 ng/ml urine). Compared with baseline, significantly more thymidine dimers were excreted every day until Day 8 (p<0.016). Our method quantifies thymidine dimers that are excreted as dimers (i.e., not degraded further) after nucleotide excision repair. This is the first published mass spectrometry-based method for quantifying thymidine dimers in the urine after whole-body UVR exposure.