Investigation of ultra wide bandgap Flouro-perovskite materials RBeF3 (R[bond, double bond]K and Li) for smart window applications: A DFT study.

The human body is affected by ultraviolet radiation because it can penetrate and harm bodily cells. Although skin cancer and early aging are consequences of prolonged exposure to ultraviolet (UV) rays, sun rays signify immediate excessive exposure. In this context, some structural, optical, electrical, and mechanical properties of the beryllium-based cubic fluoro-perovskite RBeF3 (R[bond, double bond]K and Li) compounds are examined through the use of density functional theory (DFT) within generalized gradient approximation (GGA) using the Perdew-Burke-Ernzerhof (PBE) approximations (GGA-PBE). The compounds KBeF3 and LiBeF3 have space group 221-pm3m, and their lattice constants and volumes are (3.765, 3.566) Å and (53.380, 45.379) Å3, respectively, based on their structural properties. Computed results indicate that the compounds' bandgaps are 7.35 eV and 7.12 eV, respectively, with an indirect nature for KBeF3 and LiBeF3. The properties of the band structure indicate that both compounds are insulators. The bonding properties of these compounds, RBeF3, are a combination of covalent and ionic. Optical properties of the compounds are examined which reflect the light-matter interaction like reflectivity, conductivity, and absorption. These materials were likely very hard but brittle, based on a higher bulk modulus B from elastic features, the B/G ratio, Pugh's ratio, and Vickers hardness. The compound RBeF3, as determined by the findings, is used as a UV protection and reflection layer for car and room windows.

Nutlin-3 Loaded Ethosomes and Transethosomes to Prevent UV-Associated Skin Damage.

The skin's protective mechanisms, in some cases, are not able to counteract the destructive effects induced by UV radiations, resulting in dermatological diseases, as well as skin aging. Nutlin-3, a potent drug with antiproliferative activity in keratinocytes, can block UV-induced apoptosis by activation of p53. In the present investigation, ethosomes and transethosomes were designed as delivery systems for nutlin-3, with the aim to protect the skin against UV damage. Vesicle size distribution was evaluated by photon correlation spectroscopy and morphology was investigated by cryogenic transmission electron microscopy, while nutlin-3 entrapment capacity was evaluated by ultrafiltration and HPLC. The in vitro diffusion kinetic of nutlin-3 from ethosomes and transethosomes was studied by Franz cell. Moreover, the efficiency of ethosomes and transethosomes in delivering nutlin-3 and its protective role were evaluated in ex vivo skin explants exposed to UV radiations. The results indicate that ethosomes and transethosomes efficaciously entrapped nutlin-3 (0.3% w/w). The ethosome vesicles were spherical and oligolamellar, with a 224 nm mean diameter, while in transethosome the presence of polysorbate 80 resulted in unilamellar vesicles with a 146 nm mean diameter. The fastest nutlin-3 kinetic was detected in the case of transethosomes, with permeability coefficients 7.4-fold higher, with respect to ethosomes and diffusion values 250-fold higher, with respect to the drug in solution. Ex vivo data suggest a better efficacy of transethosomes to promote nutlin-3 delivery within the skin, with respect to ethosomes. Indeed, nutlin-3 loaded transethosomes could prevent UV effect on cutaneous metalloproteinase activation and cell proliferative response.

Drinking water treatment and associated toxic byproducts: Concurrence and urgence.

Reclaimed water is highly required for environmental sustainability and to meet sustainable development goals (SDGs). Chemical processes are frequently associated with highly hazardous and toxic by-products, like nitrosamines, trihalomethanes, haloaldehydes, haloketones, and haloacetic acids. In this context, we aim to summarize the formation of various commonly produced disinfection by-products (DBPs) during wastewater treatment and their treatment approaches. Owing to DBPs formation, we discussed permissible limits, concentrations in various water systems reported globally, and their consequences on humans. While most reviews focus on DBPs detection methods, this review discusses factors affecting DBPs formation and critically reviews various remediation approaches, such as adsorption, reverse osmosis, nano/micro-filtration, UV treatment, ozonation, and advanced oxidation process. However, research in the detection of hazardous DBPs and their removal is quite at an early and initial stage, and therefore, numerous advancements are required prior to scale-up at commercial level. DBPs abatement in wastewater treatment approach should be considered. This review provides the baseline for optimizing DBPs formation and advancements in the remediation process, efficiently reducing their production and providing safe, clean drinking water. Future studies should focus on a more efficient and rigorous understanding of DBPs properties and degradation of hazardous pollutants using low-cost techniques in wastewater treatment.

Quantifying time-dependent structural and mechanical properties of UV-aged LDPE power cables insulations.

This paper reports effects of ultraviolet (UV) light radiation on the physicochemical, electrical and mechanical properties of low-density polyethylene (LDPE) cable insulating materials. Changes in structural and morphological properties of UV-aged samples were characterized by various analytical methods such as attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Additionally, elongation at break, tensile strength, dielectric strength, and optical properties were also evaluated. Changes in some physical properties of LDPE after exposing to UV irradiation clearly highlighted that the polymer underwent the structural degradation. In addition, it was also found that such degradation yielded both crosslinking and chain scission as two competing processes during UV aging.

Skin impacts from exposure to ultraviolet, visible, infrared, and artificial lights - a review.

Social distancing is conducive to grow the impact of artificial light in the daily life of the worldwide population with reported consequences to the skin. Sunlight is also essential for human development, indeed, solar radiation is composed of different types of wavelengths, which generate different skin effects. It can be divided into ultraviolet (UV), infrared (IR), and visible. UV radiation (UVA and UVB) has cutaneous biological effects ranging from photoaging, immunosuppression to melanoma formation, through the production of reactive oxygen species (ROS), inflammation and elevation of the energy state of organic molecules, changing the DNA structure. IR radiation reaches deeper layers of the skin and is also related to the generation of ROS, photoaging and erythema while visible light is responsible for generating ROS, pigmentation, cytokine formation, and matrix metallopeptidases (MMPs). Furthermore, artificial light could be harmful to the skin, as it can generate ROS, hyperpigmentation, and stimulate photoaging. Currently, we briefly summarized the cutaneous biological effects of sunlight, as well as artificial light on skin and remarked the opportunity of the evolution of current photoprotective formulas through new strategies with broad spectrum protection.

Synergic Effects of Temperature and Irradiance on the Physiology of the Marine Synechococcus Strain WH7803.

Understanding how microorganisms adjust their metabolism to maintain their ability to cope with short-term environmental variations constitutes one of the major current challenges in microbial ecology. Here, the best physiologically characterized marine Synechococcus strain, WH7803, was exposed to modulated light/dark cycles or acclimated to continuous high-light (HL) or low-light (LL), then shifted to various stress conditions, including low (LT) or high temperature (HT), HL and ultraviolet (UV) radiations. Physiological responses were analyzed by measuring time courses of photosystem (PS) II quantum yield, PSII repair rate, pigment ratios and global changes in gene expression. Previously published membrane lipid composition were also used for correlation analyses. These data revealed that cells previously acclimated to HL are better prepared than LL-acclimated cells to sustain an additional light or UV stress, but not a LT stress. Indeed, LT seems to induce a synergic effect with the HL treatment, as previously observed with oxidative stress. While all tested shift conditions induced the downregulation of many photosynthetic genes, notably those encoding PSI, cytochrome b6/f and phycobilisomes, UV stress proved to be more deleterious for PSII than the other treatments, and full recovery of damaged PSII from UV stress seemed to involve the neo-synthesis of a fairly large number of PSII subunits and not just the reassembly of pre-existing subunits after D1 replacement. In contrast, genes involved in glycogen degradation and carotenoid biosynthesis pathways were more particularly upregulated in response to LT. Altogether, these experiments allowed us to identify responses common to all stresses and those more specific to a given stress, thus highlighting genes potentially involved in niche acclimation of a key member of marine ecosystems. Our data also revealed important specific features of the stress responses compared to model freshwater cyanobacteria.

Response of Synechocystis sp. PCC 6803 to UV radiations by alteration of polyamines associated with thylakoid membrane proteins.

The responses of Synechocystis sp. PCC 6803 exposed to UVA, UVB and UVC for at least 3 h were investigated with the emphasis on the changes of polyamines (PAs) levels in whole cells, thylakoid membrane fraction, and thylakoid membrane-associated proteins fraction. All UV radiations caused a slight decrease on cell growth but a drastic reduction of photosynthetic efficiency of Synechocystis cells. UV radiations, especially UVB and UVC, severely decreased the levels of PAs associated with thylakoid membrane proteins. The decreased PAs levels as affected by UV radiation correlated well with the decrease of photosynthetic efficiency, suggesting the role of PAs for the maintenance of photosynthetic activity of Synechocystis. PAs, especially spermidine (Spd) and putrescine (Put), were found abundantly in the thylakoid membrane fraction, and these PAs were associated mainly with the PSI trimer complex. Importantly, the exposure of Synechocystis cells to all UV radiations for 3 h resulted in the increase of Spd associated with the PSII monomer and dimer complex, suggesting its protective role against UV radiations despite the overall decrease of PAs.

Protective Activity of Silk Sericin against UV Radiation-Induced Skin Damage by Downregulating Oxidative Stress.

Topical delivery of potential antioxidants protects the skin against ultraviolet (UV) radiation-induced oxidative damage through maintaining redox balance. Sericin, one of the major components of silk, possesses antioxidant property along with skin-protective activity against UVB radiation-induced damage. However, the protective activity of silk sericin (SS) extracted from different sources has not been explored against UVA and UVB radiation-induced oxidative damage. In the present study, we have systematically investigated the protective activity of sericin against UVA and UVB radiation-induced skin damage. MTT and neutral red assays showed that Philosamia ricini sericin (PRS) and Antheraea assamensis sericin (AAS) (10 µg/mL) treatment prior to UVA (12 J/cm2) and UVB (120 mJ/cm2) irradiations enhanced the viability of human keratinocytes. Examination of cell cycle arrest and apoptotic/necrotic cell death using flow cytometry showed that sericin treatment before UVA and UVB irradiation protected the cells from apoptotic cell death by arresting the cell cycle at G1 phase. Sericin pretreatment downregulated the interleukin (IL)-6 and IL-8, upregulated p53 and decrease the dysregulation of Bcl-2/Bax gene expression. AAS treatment prior to UVB irradiation significantly reduced skin inflammation, DNA fragmentation, and lipid peroxidation in the female SKH-1 hairless mouse skin. Altogether, our results substantiate the use of AAS in effectively ameliorating UVA and UVB radiation-induced skin damage, which holds prospects as a potent antioxidant supplement in the preparation of skin care products.

Ultraviolet Radiations: Skin Defense-Damage Mechanism.

UV-radiations are the invisible part of light spectra having a wavelength between visible rays and X-rays. Based on wavelength, UV rays are subdivided into UV-A (320-400 nm), UV-B (280-320 nm) and UV-C (200-280 nm). Ultraviolet rays can have both harmful and beneficial effects. UV-C has the property of ionization thus acting as a strong mutagen, which can cause immune-mediated disease and cancer in adverse cases. Numbers of genetic factors have been identified in human involved in inducing skin cancer from UV-radiations. Certain heredity diseases have been found susceptible to UV-induced skin cancer. UV radiations activate the cutaneous immune system, which led to an inflammatory response by different mechanisms. The first line of defense mechanism against UV radiation is melanin (an epidermal pigment), and UV absorbing pigment of skin, which dissipate UV radiation as heat. Cell surface death receptor (e.g. Fas) of keratinocytes responds to UV-induced injury and elicits apoptosis to avoid malignant transformation. In addition to the formation of photo-dimers in the genome, UV also can induce mutation by generating ROS and nucleotides are highly susceptible to these free radical injuries. Melanocortin 1 receptor (MC1R) has been known to be implicated in different UV-induced damages such as pigmentation, adaptive tanning, and skin cancer. UV-B induces the formation of pre-vitamin D3 in the epidermal layer of skin. UV-induced tans act as a photoprotection by providing a sun protection factor (SPF) of 3-4 and epidermal hyperplasia. There is a need to prevent the harmful effects and harness the useful effects of UV radiations.

Radiaciones ultravioletas como factor de riesgo vinculado a la génesis del pterigión en trabajadores expuestos / UV radiations as a risk factor associated to pterygium genesis in exposed workers

Introducción: las radiaciones ultravioletas representan un factor de riesgo para los trabajadores que por razones de su oficio deben laborar a cielo abierto. Objetivos: relacionar las radiaciones ultravioletas como factor de riesgo relacionado con la génesis del pterigión en personas expuestas laboralmente. Métodos: estudio descriptivo correlacional, retrospectivo, diseño documental; realizado en una población 98 trabajadores dedicados, en su mayoría, a actividades a cielo abierto. La recogida de datos se hizo mediante análisis de registros ocupacionales en la Institución prestadora de servicios de Salud Ocupacional, CERINPROS. El análisis estadístico se realizó mediante correlación de Pearson y odd ration. Resultados: la distribución por sexo muestra el 83,67 por ciento de sexo masculino y 16,33 por ciento sexo femenino, con una media de edad de 35,3 años, con significancia estadística de exposición de radiaciones ultravioletas como factor de riesgo en la generación de pterigión de 4,56, para un índice de confianza de 95 por ciento. Correlación positiva entre actividad/exposición y edad/exposición. Conclusiones: en el presente estudio, las radiaciones ultravioletas representaron un factor de riesgo para la producción de pterigión(AU)

Introduction: UV radiations represent a risk factor to workers who labors on open-air spaces due to reasons of their jobs. Objective: Associate UV radiations as a risk factor related with pterygium genesis in work-exposed persons. Methods: Correlational, descriptive, retrospective study, and documental design, carried out in a target group of 98 workers dedicated mostly to open-air spaces activities. Data collection was performed by the analysis of occupational records in the institution providing occupational health care, CERINPROS. Statistical analysis was performed by odd ration and Pearson correlation coefficient. Results: Distribution by sex shows 83.67 percent of male sex and 16.22 percent of female sex, with a mean age of 35.3 years, with a 4.56 value of statistical significance of UV radiations exposition as a risk factor in pterygium genesis, for a confidence rate of 95 percent. There was a positive correlation between activity/exposition and age/exposition. Conclusions: In this study, UV radiations represented a risk factor for the production of genesis(AU)

Radiaciones ultravioletas como factor de riesgo vinculado a la génesis del pterigión en trabajadores expuestos / UV radiations as a risk factor associated to pterygium genesis in exposed workers

Introducción: las radiaciones ultravioletas representan un factor de riesgo para los trabajadores que por razones de su oficio deben laborar a cielo abierto. Objetivos: relacionar las radiaciones ultravioletas como factor de riesgo relacionado con la génesis del pterigión en personas expuestas laboralmente. Métodos: estudio descriptivo correlacional, retrospectivo, diseño documental; realizado en una población 98 trabajadores dedicados, en su mayoría, a actividades a cielo abierto. La recogida de datos se hizo mediante análisis de registros ocupacionales en la Institución prestadora de servicios de Salud Ocupacional, CERINPROS. El análisis estadístico se realizó mediante correlación de Pearson y odd ration. Resultados: la distribución por sexo muestra el 83,67 por ciento de sexo masculino y 16,33 por ciento sexo femenino, con una media de edad de 35,3 años, con significancia estadística de exposición de radiaciones ultravioletas como factor de riesgo en la generación de pterigión de 4,56, para un índice de confianza de 95 por ciento. Correlación positiva entre actividad/exposición y edad/exposición. Conclusiones: en el presente estudio, las radiaciones ultravioletas representaron un factor de riesgo para la producción de pterigión(AU)

Introduction: UV radiations represent a risk factor to workers who labors on open-air spaces due to reasons of their jobs. Objective: Associate UV radiations as a risk factor related with pterygium genesis in work-exposed persons. Methods: Correlational, descriptive, retrospective study, and documental design, carried out in a target group of 98 workers dedicated mostly to open-air spaces activities. Data collection was performed by the analysis of occupational records in the institution providing occupational health care, CERINPROS. Statistical analysis was performed by odd ration and Pearson correlation coefficient. Results: Distribution by sex shows 83.67 percent of male sex and 16.22 percent of female sex, with a mean age of 35.3 years, with a 4.56 value of statistical significance of UV radiations exposition as a risk factor in pterygium genesis, for a confidence rate of 95 percent. There was a positive correlation between activity/exposition and age/exposition. Conclusions: In this study, UV radiations represented a risk factor for the production of genesis(AU)

Thymol and Thymus Vulgaris L. activity against UVA- and UVB-induced damage in NCTC 2544 cell line.

Many authors focused on the research of natural compounds in order to protect skin from indirect (UVA) and direct (UVB) ultraviolet radiation side effects. The aim of this study to evaluate the protective effect of a dry extract from T. vulgaris L. and of its major synthetic compound thymol (about 60%), against oxidative and genotoxic UVA- and UVB damage. Experiments were reproduced in a low differentiated keratinocytes cell line (NCTC 2544) Cells were pretreated for 1h, in serum-free medium, with thymol (1µg/mL) or T. vulgaris L. (1.82µg/mL) then exposed to different UVA (8-24J/cm(2)) or UVB doses (0.016-0.72J/cm(2)). Immediately after the UV exposure the intracellular redox status was evaluated by ROS quantification and by LPO. Genotoxic aspects were evaluated 24h after the end of irradiations using the alkaline comet assay, the micronucleus formation assay and the immunostaining of phosphorylated H2AX histone protein (detected 1h after the end of UV exposure). Thymol and T. vulgaris L. extract inhibited ROS generation in UVA and UVB-irradiated cells. On the contrary, MDA formation was reduced only in UVA treated cells. Both agents decreased the DNA damage evaluated by the alkaline comet assay, but not in the micronucleus and H2AX tests probably because of the severity of damage (double strands) detected.

Prochlorococcus and Synechococcus have Evolved Different Adaptive Mechanisms to Cope with Light and UV Stress.

Prochlorococcus and Synechococcus, which numerically dominate vast oceanic areas, are the two most abundant oxygenic phototrophs on Earth. Although they require solar energy for photosynthesis, excess light and associated high UV radiations can induce high levels of oxidative stress that may have deleterious effects on their growth and productivity. Here, we compared the photophysiologies of the model strains Prochlorococcus marinus PCC 9511 and Synechococcus sp. WH7803 grown under a bell-shaped light/dark cycle of high visible light supplemented or not with UV. Prochlorococcus exhibited a higher sensitivity to photoinactivation than Synechococcus under both conditions, as shown by a larger drop of photosystem II (PSII) quantum yield at noon and different diel patterns of the D1 protein pool. In the presence of UV, the PSII repair rate was significantly depressed at noon in Prochlorococcus compared to Synechococcus. Additionally, Prochlorococcus was more sensitive than Synechococcus to oxidative stress, as shown by the different degrees of PSII photoinactivation after addition of hydrogen peroxide. A transcriptional analysis also revealed dramatic discrepancies between the two organisms in the diel expression patterns of several genes involved notably in the biosynthesis and/or repair of photosystems, light-harvesting complexes, CO(2) fixation as well as protection mechanisms against light, UV, and oxidative stress, which likely translate profound differences in their light-controlled regulation. Altogether our results suggest that while Synechococcus has developed efficient ways to cope with light and UV stress, Prochlorococcus cells seemingly survive stressful hours of the day by launching a minimal set of protection mechanisms and by temporarily bringing down several key metabolic processes. This study provides unprecedented insights into understanding the distinct depth distributions and dynamics of these two picocyanobacteria in the field.

Comportamiento del pterigión según la exposición a radiaciones ultravioletas y sus cambios histológicos de acuerdo con su severidad / Behavior of pterygium in terms of exposure to UV radiations and its histological changes depending on severity

OBJETIVO: Valorar el comportamiento del pterigión diagnosticado, atendiendo a la exposición a radiaciones ultravioletas y a los cambios histológicos según su severidad. MÉTODOS: Se realizó un estudio descriptivo y transversal en pacientes operados en el Instituto Cubano de Oftalmología "Ramón Pando Ferrer" con diagnóstico clínico de pterigión, en el período comprendido entre enero y diciembre de 2006. La muestra estuvo constituida por 101 pacientes adultos que se sometieron a la cirugía, lo que consistió en la excéresis del pterigión y la selección fue al azar, sin distinción de edad, sexo, ni país de procedencia. RESULTADOS: La exposición a la luz ultravioleta guardó relación estadística significativa con el sexo masculino, con el aumento de la edad de los grupos y con los grados de afectación según la prueba de chi cuadrado. CONCLUSIONES: El estudio histológico según el grado del pterigión no mostró diferencia alguna, pues en la totalidad de las piezas analizadas se encontró la misma composición histológica.

OBJECTIVE: To asses the behaviour of diagnosed pterygium, taking into account exposure to UV radiations and the histological changes according to severity. METHODS: A cross-sectional descriptive study was performed on patients operated on at "Ramón Pando Ferrer" Cuban Ophthalmology Institute from pterygium from January to December, 2006. The sample was made up of 101 adult patients who underwent pterygium removal, and they were randomly selected regardless of age, sex and place of origin. RESULTS: Exposure to UV light was statistically related in a significant way with male sex, increase of age and level of impact according to the applied Chi-square test. CONCLUSIONS: The histological study did not show any difference since the same histological composition was found in the whole sample.