Sun's Ultraviolet Radiation Research Articles

Characterization, development and evaluation of a cream by using terminalia chebula and cucumber sativus extracts

Background: Continual exposure to the sun's ultraviolet radiation damages skin. Freckles are little brown patches that develop on the skin after repeated sun exposure. Terminalia chebula and Cucumber Sativus extracts-infused water in oil (W/O) emulsion is created, that has anti-freckle and emollient effect. Methodology: Base with no extract and formulation containing three different extract concentrations 4% of Terminalia Chebula with 1% Cucumber Sativus, 5% T. Chebula with 2% C. Sativus and 6% of T. Chebula with 3% of C. Sativus are formulated and after 4 weeks of study and their stability parameters are evaluated at 8oC, 25oC, 40oC and 40oC + 75RH. Different parameters such as anti freckle effect, skin melanin, skin moisture content, sebum level and TEW loss level are investigated by applying these formulations on the volunteer’s cheeks for 4 weeks. Results: Skin melanin levels, sebum level, moisture level and TEW loss level of three formulations containing both plant extracts are significant statistically (p < 0.05). Skin melanin level and TEW loss are decreased after application of cream. But skin moisture and sebum level are increased after application of formulation.

HS‐UNET‐ID: An approach for human skin classification integrating between UNET and improved dense convolutional network

AbstractThe Sun's ultraviolet radiation, toxic chemicals from industry, and other factors can cause problems to human skin. These factors have boosted the risk of humans contracting skin cancer. In identifying and detecting signals of skin cancer diseases, recent advancements in deep learning techniques significantly improve the accuracy of diagnosis. This work delves into processing techniques for human skin images with MorphologyEx (blackhat), thresholding, semantic segmentation with UNET, and several famous convolutional neural network architectures to improve skin classification performance. If skin cancer can be stopped in the first stage, the survival rate of the patient could be more than 95%, while it drops to just 5% if the detection is carried lately in Stage IV4. Due to its seriousness, the healthcare and research community has received considerable attention, and its most important goal is to be able to diagnose it at an early stage. However, the challenge due to the similarity in melanocytic and non‐melanoma skin lesions is inevitable. We achieved skin classification performances of 0.8560, 0.9672, 0.8063, and 0.8560 measured by overall accuracy, area under curve, Matthews correlation coefficient, and F1‐score, respectively. The proposed approach has been deployed into applications on Mobile and Web platforms.

FORMULATION AND IN VITRO SPF EVALUATION OF BREADFRUIT LEAVES [Artocarpus altilis (Parkinson) Fosberg] SUNSCREEN CREAM

Sunscreen, also known as sunblock, is a photoprotective topical product for the skin that absorbs or reflects some of the sun's ultraviolet radiation and thus helps protect against sunburn. Breadfruit leaves are one of the natural substances that could be used as sunscreen. It contains flavonoids, which may help to protect against the detrimental effects of UV rays. The goal of this study is to determine the formula of a sunscreen cream made from breadfruit leaves extract that meets excellent physical quality standards, as well as the results of an in vitro SPF value test using breadfruit leaves extract as a sunscreen cream preparation. The study was designed as a laboratory-based experiment. Breadfruit leaves extract prepared using the reflux method was employed in this study. Furthermore, the viscous extract was transformed into a sunscreen cream, which was then evaluated either physically or by calculating the SPF value. The results showed that breadfruit leaves extract at 200 ppm had an SPF of 19.023 in the ultra protection category while the sunscreen cream had an SPF of 18.624 in the ultra protection category at a concentration of 10.000 ppm. The UV protection of the sunscreen cream made from breadfruit leaves extract is excellent. Keywords: Breadfruit leaves, cream, sunscreen, SPF

Sun ultraviolet radiation in Ibarra, Ecuador and its relation to vitamin D synthesis

In the present work, we determined the necessary time to unchain the synthesis of vitamin D for a phototype II skin in Ibarra, Ecuador. In a specific sky situation, the range of exposure time at Sun radiation is 4 to 6 minutes depending on the month of the year, but with clouds, it is needed about 70% more exposure time. This time range is easily reached in normal conditions, but during a lockdown period, as in pandemic situations like the COVID 19 one or for people that need to live, work or study inside, if they are exposed to the direct Sun for the minutes indicated above, they will have a natural vitamin D supplement that will improve its health.

A cross-sectional survey of prevalence and correlates of sunscreen use among a rural Tri-State Appalachian population.

Over five million people are diagnosed with skin cancers each year. With the sun's ultraviolet radiation exposure being the major risk factor for all skin cancers, sunscreen use is a vital preventative measure. However, in the US, sunscreen use remains inadequate. Furthermore, research regarding sunscreen use amongst rural populations has been particularly sparse. To identify the prevalence of sunscreen use and identify correlates thereof, a cross-sectional study was conducted on a sample of patients from rural Tri-State Appalachia. A total of 212 patients participated in this study. Findings showed that young individuals, females and those with higher educational attainment were more likely to utilize sunscreen. Furthermore, individuals with skin types prone to burning were four times as likely to utilize sunscreen. Overall, sunscreen use amongst residents in the Tri-State area was low, emphasizing the need for targeted interventions to prevent the incidence of skin cancer amongst this population.

Oxidative stress-mediated photoactivation of carbazole inhibits human skin cell physiology.

Prolonged exposure of the earth's surface to the sun's ultraviolet radiation may result in various skin diseases and cataract. Carbazole (CBZ), as a polycyclic-aromatic hydrocarbon (PAH), is blended with a five-member nitrogen-containing ring. It is found in cigarette smoke, coal, eye kohl, tattoo ink, and wood combustion and affects various types of flora and fauna. Our findings suggest that CBZ generates reactive oxygen species (ROS) like through type-I photodynamic reaction and causes phototoxicity in the human keratinocyte cell line (HaCaT), which has been proved by mitochondrial dehydrogenase and neutral red uptake assays. CBZ induces single strand DNA damage. We have investigated the involvement of the apoptotic pattern of cell death and confirmed it by cytochrome C release from mitochondria and caspase-9 activation. Similarly, photo-micronuclei formation was associated to CBZ-induced phototoxicity. The results of this study strongly support that the upregulation of bax, cyto-C, apaf-1, casp-9 and down regulation of bcl2, keap-1, nrf-2, and hmox-1 genes cause apoptopic cell death. Downregulation of antioxidant genes showed a significant amount of ROS generation by photosensitized CBZ. Therefore, the current study will be a step forward to safeguard human beings from sunlight-induced photosensitive CBZ prolonged exposure.

Promoting UV Exposure Awareness with Persuasive, Wearable Technologies.

Current methods to promote awareness of the sun's ultraviolet (UV) radiation have focussed on delivering population level information and some location-based reporting of UV Index (UVI). However, diseases related to excessive (e.g. sunburn, skin cancer) or insufficient (e.g. vitamin D deficiency) exposure to sunlight still remain a global burden. The emergence of wearable sensors and the application of persuasive technology in health domains raise the possibility for technology to influence awareness of sufficient sun intake for vitamin D production, as well as preventing risk of skin damage. This paper presents a personalised solution to promote healthy, safe sun exposure using wearable devices and persuasive techniques.

Lignin for white natural sunscreens

Long-time exposure to the sun's ultraviolet (UV) radiation is harmful and causes various skin problems. Natural sun blockers have been drawing considerable attention recently. Even though lignin, an abundant aromatic polymer from plants, is a natural UV screening agent, its unfavorable dark color hinders its high value-added applications in sunscreens and cosmetics. In this study, we separate lignin under mild conditions (at room temperature with neutral solvents) in order to prevent darkening occurring during delignification and apply the resultant lignin as a natural sunscreen ingredient for the first time. Lignins isolated from Miscanthus sacchariflorus (MWL-M) and from Pinus densiflora (MWL-P) are compared with organosolv lignin (OL), which showed the best sunscreen performance, in color and UV protection. MWLs separated under mild conditions were light in color unlike conventional lignins extracted under harsh conditions. UV absorption of light-colored MWL-M was revealed to be as high as dark-colored OL. MWLs also showed synergistic effects with a commercial sunscreen; exposure of the MWL-added sunscreen to UVA radiation greatly enhanced the sun protection factor (SPF) value of the sunscreen.

The Effect of Educational Intervention Based on Health Belief Model and Social Support on Promoting Skin Cancer Preventive Behaviors in a Sample of Iranian Farmers.

Skin cancer is one of the most common cancers in Iran. Farmers are exposed to the sun's ultraviolet radiation due to their job and are susceptible to skin cancer. The aim of this study is to survey the effect of educational intervention based on health belief model and social support on promoting skin cancer preventive behaviors in farmers of Fasa City, Fars province, Iran. In this quasi-experimental study, 200 farmers (100 in experimental group and 100 in control group) in Fasa City, Fars, Iran, were selected in 2017. The educational intervention for the experimental group consisted of eight training sessions (introduction to skin cancer, risk factors, complications, benefits and barriers to proper use of sunscreen, UV sunglasses and physical protection, self-efficacy in applying preventive behaviors, role of social support). A questionnaire consisting of demographic information, knowledge, HBM constructs (perceived susceptibility, severity, benefits, barriers, self-efficacy and cues to action), and social support was used to measure skin cancer preventive behaviors before, 3months after the intervention, and 6months later. Data were analyzed using SPSS-22 via chi-squared, independent samples t test, Mann-Whitney, and repeated measures ANOVA at a significance level of 0.5. The mean age of the farmers was 42.21 ± 10.52years in the experimental group and 44.28 ± 10.16years in the control group. Three months after the intervention and 6months after the intervention, the experimental group showed a significant increase in the knowledge, perceived susceptibility, perceived severity, perceived benefits, self-efficacy, cues to action, social support, and skin cancer preventive behaviors compared to the control group. This study showed the effectiveness of the intervention based on the HBM constructs and social support in adoption of skin cancer preventive behaviors in 3 and 6months post intervention in farmers. Hence, these models can act as a framework for designing and implementing educational interventions for the prevention of skin cancer.

Towards a high performing UV-A sensor based on Silicon Carbide and hydrogenated Silicon Nitride absorbing layers

Exposure to ultraviolet (UV) radiation is a major risk factor for most skin cancers. The sun is our primary natural source of UV radiation. The strength of the sun's ultraviolet radiation is expressed as Solar UV Index (UVI). UV-A (320–400 nm) and UV-B (290–320 nm) rays mostly contribute to UVI. UV-B is typically the most destructive form of UV radiation because it has enough energy to cause photochemical damage to cellular DNA. Also overexposure to UV-A rays, although these are less energetic than UV-B photons, has been associated with toughening of the skin, suppression of the immune system, and cataract formation. The use of preventive measures to decrease sunlight UV radiation absorption is fundamental to reduce acute and irreversible health diseases to skin, eyes and immune system. In this perspective UV sensors able to monitor in a monolithic and compact chip the UV Index and relative UV-A and UV-B components of solar spectrum can play a relevant role for prevention, especially in view of the integration of these detectors in close at hand portable devices. Here we present the preliminary results obtained on our UV-A sensor technology based on the use of hydrogenated Silicon Nitride (SiN:H) thin passivating layers deposited on the surface of thin continuous metal film Ni2Si/4H-SiC Schottky detectors, already used for UV-Index monitoring. The first UV-A detector prototypes exhibit a very low leakage current density of about 0.2 pA/mm2 and a peak responsivity value of 0.027 A/W at 330 nm, both measured at 0V bias.

The Thermodynamics of Climate Change

When you stand in sunlight, you feel hot, but when you stand outside at night, you feel cool, even on a warm night. Why? Because Sun emits ultraviolet radiation that is hot enough to burn your skin, while Earth emits infrared radiation that is, on average, 21°C cooler than your body. Computer models based on greenhouse-gas theory have this backward. They calculate that Earth is heated more by its own infrared radiation than by Sun's ultraviolet radiation. Your personal experience strongly suggests that these models are wrong. In this paper we show that thermal energy consists of the frequencies and amplitudes of oscillation of all the degrees of freedom of all the bonds that hold matter together. These frequencies and amplitudes of oscillation on the surface of matter transmit thermal energy through air and space as electromagnetic radiation. Climate models assume that electromagnetic radiation (EMR) travels as waves through space, but that assumption is unwarranted because the physical properties of EMR and mechanical waves in matter are very different. Observations of climate change can be explained quite clearly by ozone depletion. Ozone absorbs ultraviolet radiation from Sun, warming the ozone layer 20 to 30 km above Earth's surface. When there is less ozone, more of this hot ultraviolet radiation is observed to reach Earth's surface, warming Earth instead of the ozone layer.

Skin cancer in rural workers: nursing knowledge and intervention

To identify the exposure of rural workers to the sun's ultraviolet radiation and pesticides; to identify previous cases of skin cancer; and to implement clinical and communicative nursing actions among rural workers with a previous diagnosis of skin cancer. Observational-exploratory study conducted with rural workers exposed to ultraviolet radiation and pesticides in a rural area in the extreme south of Brazil. A clinical judgment and risk communication model properly adapted was used to develop interventions among workers with a previous history of skin cancer. A total of 123 (97.7%) workers were identified under conditions of exposure to the sun's ultraviolet radiation and pesticides; seven (5.4%) were identified with a previous diagnosis of skin cancer; four (57.1%) of these presented potential skin cancer lesions. This study's results enabled clarifying the combination of clinical knowledge and risk communication regarding skin cancer to rural workers.

Sun Protection for Children: A Review

Chronic ultraviolet exposure results in premature skin aging (photoaging), dyspigmentation, sallow color, textural changes, loss of elasticity, and premalignant actinic keratoses. UVB radiation is mainly responsible for acute damages such as sunburn, and long-term damage including melanoma. Today the sun's ultraviolet radiation (UVR) induced skin cancer is a major issue worldwide. History of sun exposure and sunburns are the most important behavioral risks. Childhood sun exposure is considered as a substantial risk because a child’s skin has a thinner stratum corneum, lower levels of protective melanin, and a higher surface area to body-mass-ratio. Thus, protection against UVR in childhood is essential. Research has shown that people who have had a sunburn in childhood or were in the sun unprotected are more likely to have skin cancer. In this article, we review the literature to address the protection of children against sun and skin cancer.

Vitamin D Deficiency in Indians? Prevalence and the Way Ahead

Vitamin D is endogenously synthesized in human beings from photo conversion of 7-dehydrocholestrol in the skin to cholecalciferol on exposure to ultraviolet radiation of sun. In a tropical country like India, where sunlight exposure is abundant, vitamin D deficiency seems unlikely. However, as opposed to this, various studies have highlighted that 70-100% Indians in different age groups vitamin

Thin Metal Film Ni2Si/4H—SiC Vertical Schottky Photodiodes

Photodetection in the ultraviolet (UV) region has drawn extensive attention owing to its various applications in industrial, environmental, and even biological fields. In this letter, we report on the morphological and electro-optical characteristics of continuous thin metal film Ni 2 Si/4H-SiC photodiodes properly designed for the realization of an extremely compact digital sensor suited to measure the total sun UV radiation for environmental UV light monitoring.

PMMA Wettability Caused by Ultraviolet Radiation

Poly methyl metha acrylate (PMMA) is widely in use for eye prostheses and contact lenses. The latter is under ultraviolet radiation of Sun. Therefore the PMMA properties could be influenced and bring the patient to discomfort, because of polymer surface wettability alteration. The latter is under the focus of the present research. Wettability and electron work experiments show similar tendencies, also high correlation has been found between electron work function and absorption minimum area. More interestingly - surface electrical potential depended on exposure under light.

Mitochondrial electron transport chain activity is not involved in ultraviolet A (UVA)-induced cell death

Ultraviolet A (UVA), the long wavelength part of the sun's ultraviolet radiation, elicits its harmful effects through production of reactive oxygen species. In this study, we have tested the hypothesis that the mitochondrial electron transport chain, the main source of reactive oxygen species in cells, importantly contributes to UVA-induced cell damage. Model cell lines completely lacking a mitochondrial electron transport chain (ρ 0-cells) were not protected against UVA-induced cell death. Also, primary human fibroblasts and keratinocytes with induced depletion of electron transport chain activity were not better protected against UVA-induced cell death. On the other hand, diphenyleneiodonium and resiniferatoxin, inhibitors of plasma membrane oxidases, protected primary human fibroblasts against UVA, as potently as the lipid peroxidation chain breaker Trolox. These data indicate that plasma membrane electron transport systems, but not the mitochondrial electron transport chain, play a major role in UVA-induced cell death.

P53 mutations as a marker of skin cancer risk: comparison of UVA and UVB effects.

The epidermis is excellently adapted to the sun's ultraviolet (UV) radiation. The p53 protein plays a crucial role in the orchestration of a cell's response to UV-induced damage, and more specifically to DNA damage. This response appears to differ between differentiated (suprabasal) and undifferentiated (basal) epidermal cells. The latter are the most likely targets in UV carcinogenesis. The UVB-related mutations in p53 genes of human carcinomas from sun-exposed skin indicate that rendering p53 dysfunctional is an important (early) step in the formation of these tumors. Experiments in hairless mice confirm this finding for UVB-driven carcinogenesis, but not for UVA1-(365-nm)-driven carcinogenesis. Microscopic clusters of preneoplastic cells overexpressing mutant p53 occur in chronically UVB-exposed murine skin long before the ultimate carcinomas. The number of these clusters at a certain time-point appears to be predictive of the tumor risk at latter time-points. These UVB-induced p53 clusters appear to be suitable surrogates of tumors in short-term experiments.

Persistence of lactase activity among Northern Europeans: A weighing of evidence for the calcium absorption hypothesis

Considered in this paper is a broad range of evidence bearing on the calcium absorption hypothesis that has been advanced to explain high frequencies of the gene for persistence of lactase activity (PLA) among adults in northern Europe. According to that hypothesis, lactase‐sufficient individuals in early northern Europe enjoyed a selective advantage over lactase‐deficient ones that led to high incidences of PLA in adults of the region. Northern Europeans, the hypothesis goes, suffered from a dietary shortage of vitamin D and, in addition, were unable to synthesize adequate vitamin D from the sun's ultraviolet radiation because of northern Europe's cloudiness and its location in higher latitudes. This led to chronic vitamin D deficiency along with a reduced ability to absorb calcium from milk and lactose‐rich dairy products. As a result, the deficiency diseases rickets—which affects infants and children and can leave a child with bowlegs and other bone defects—and osteomalacia—which weakens and deforms the bones of adults—were common in early northern Europe, and represented powerful selective forces that contributed to development of the highly depigmented skin that is typical of the region's peoples. In addition, the hypothesis goes, calcium absorption was enhanced by a process independent of vitamin D. Such enhancement, found especially or solely among lactase‐sufficient individuals, was brought on by ingestion of lactose in milk and milk products. Thus, persons who enjoyed high lactase activity through life were favored in the struggle for survival, which ultimately led northern European peoples to have among the highest incidences of PLA in the world. In this article, evidence, much of it recent, is presented to show that lactase‐deficient humans are able to absorb calcium from milk as readily, or nearly as readily, as lactase‐sufficient humans. Evidence is also presented that rickets and osteomalacia occur in parts of the world that have an abundance of sunshine, whether originating from customs that limit exposure to sunshine or otherwise; that heavy cloud cover and high latitude need not result in vitamin D deficiency, rickets, and osteomalacia; that, indeed, osteological evidence from archeological sites in northern Europe indicates that rickets and osteomalacia were quite rare in antiquity; that those conditions appear to have become common in northern Europe only with the advent of the Industrial Revolution, too short a time to have been a significant factor in bringing on the high incidences of PLA that prevail today; and that, indeed, the calcium absorption hypothesis is not confirmed by historical, osteoarcheological, or bio‐medical evidence.

Health effects from the sun's ultraviolet radiation and ozone as a stratospheric sunscreen

Health effects from the sun's ultraviolet radiation and ozone as a stratospheric sunscreen