Ultraviolet Radiation In Sunlight Research Articles

Photopatch testing: Clinical characteristics, test results, and final diagnoses from the North American Contact Dermatitis Group, 2009-2020.

Photoallergic contact dermatitis (PACD) is a delayed hypersensitivity reaction to allergens only in the presence of ultraviolet radiation in sunlight. Photopatch testing (PhotoPT) is necessary to confirm the diagnosis of PACD. There are few published studies of PhotoPT in North America. To summarise the results of patients photopatch tested by members of the North American Contact Dermatitis Group (NACDG), 2009-2020. Retrospective analysis of patient characteristics and PhotoPT results to 32 allergens on the NACDG Photopatch Test Series. Most of the 454 tested patients were female (70.3%), 21-60 years old (66.7%) and White (66.7%). There were a total of 119 positive photopatch tests. Sunscreen agents comprised 88.2% of those, with benzophenones responsible for over half of them. Final diagnoses included PACD in 17.2%, allergic contact dermatitis (ACD) in 44.5%, polymorphous light eruption (PMLE) in 18.9% and chronic actinic dermatitis (CAD) in 9.0% of patients. In 454 patients with suspected photosensitivity referred for photopatch testing in North America, approximately one-fifth had PACD. Sunscreen agents, especially benzophenones, were the most common photoallergens. Other common diagnoses included ACD, PMLE and CAD. Photopatch testing is an important tool for differentiating these conditions.

Nitrogen-Doped Carbon Quantum Dots with Photoactivation Properties for Ultraviolet Ray Detection.

Photoactivation is a phenomenon that could enhance the photoluminescence (PL) and photostability upon UV/vis light exposure, which is usually observed in CdSe/ZnS quantum dots (QDs). However, the photoactivation phenomenon has been scarcely reported in fluorescent carbon quantum dots (CQDs). Herein, the nitrogen-doped carbon quantum dots (N-CQDs) were prepared through a facile solvothermal approach with naphthalenetracarboxylic dianhydride and serine as precursors. Upon simple UV light irradiation for 10 min, the fluorescence quantum yield (QY) of N-CQDs could increase up to 10-fold. Based on this phenomenon, the N-CQDs were explored as an ultraviolet (UV) light sensor to assess the intensity of ultraviolet radiation in sunlight and indirectly evaluate the UV-blocking efficiency of various sunscreen products. Thus, this contribution not only provided an insight into developing a low-cost UV detector but also opened a door for the development of carbon quantum dots with converse-photobleaching properties.

Globally Estimated UVB Exposure Times Required to Maintain Sufficiency in Vitamin D Levels.

A paucity of vitamin D is a common deficiency globally, with implications for many aspects of health besides the well-known impact on musculoskeletal health. The two sources of vitamin D are through oral intake, or through endogenous synthesis in the skin when exposed to ultraviolet radiation in sunlight. Assessing nutritional needs, whether by food, food fortification or supplementation, is aided by an understanding of local potential for cutaneous synthesis of the vitamin, dependent on latitude and climate, personal skin type and local culture. To aid these discussions we provide indicative exposure times for the maintenance of vitamin D status as a function of latitude, month and skin type, for the clear-sky case and all-sky conditions, for an ambulatory person wearing modest skirt/shorts and T-shirt. At latitudes greater than ±40 degrees, lack of available sunlight limits vitamin D synthesis in some months for all, while at the equator exposure times range from 3 to 15 min at noontime, for white and black skin, respectively. Rather than a sun exposure prescription, the data are intended to show where nutritional vitamin D intake is necessary, advisable, or can be mitigated by sun exposure, and allows for such advice to be personalized to account for different sub-groups in a multicultural population.

Sunlight ultraviolet radiation dose is negatively correlated with the percent positive of SARS-CoV-2 and four other common human coronaviruses in the U.S.

Human coronaviruses are RNA viruses that are sensitive to ultraviolet (UV) radiation. Sunlight contains UVA (320–400 nm), UVB (260–320 nm) and UVC (200–260 nm) action spectra. UVC can inactivate coronaviruses, including severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). The incidence and mortality of coronavirus disease 2019 (COVID-19) are considered to be correlated with vitamin D levels. Vitamin D synthesis in human skin is closely related to exposure to UVB radiation. Therefore, the incidence and mortality of COVID-19 are also considered to be correlated with Vitamin D levels. In this study, Spearman and Kendall rank correlation analysis tests were used to analyze the correlation between the average percent positive of five human coronaviruses (SARS-CoV-2, CoVHKU1, CoVNL63, CoVOC43, and CoV229E) in the U.S. and the corresponding sunlight UV radiation dose The results indicated that the monthly average percent positive of four common coronaviruses was significantly negatively correlated with the sunlight UV radiation dose. The weekly percent positive of SARS-CoV-2 during April 17, 2020 to July 10, 2020 showed a significant negative correlation with the sunlight UV radiation dose in census regions 1 and 2 of the U.S. while no statistical significance in the other regions. Additionally, sunlight UV radiation also showed some negative effects with respect to the early SARS-CoV-2 transmission.

Interactive Effects of Ultraviolet Radiation and Dissolved Organic Carbon on Phytoplankton Growth and Photosynthesis in Sanya Bay, Northern South China Sea

The effects of a simulated climate change scenario, i.e., increased ultraviolet radiation (UVR) and dissolved organic carbon (DOC), on the growth and photosynthesis of tropical coastal phytoplankton were evaluated in Sanya Bay, northern South China Sea, in summer. Microcosm experiments were conducted at two contrasting stations (Stns S1 and S2) with three different UVR treatments and two DOC addition treatments. Our results showed that natural sunlight UVR or increased UV-B did not affect phytoplankton biomass and primary production. However, increased UV-B significantly decreased the proportion of picophytoplankton and the efficiency of carbon fixation at Stn S2. DOC enhancement caused negative effects on primary production under natural sunlight UVR only at Stn S1. Interactive effects of UVR and DOC addition on phytoplankton biomass and primary production were detected at Stn S1, due to the negative effects of DOC being eliminated under the increased UV-B condition. The lack of interactive effects at Stn S2 were likely due to the differences with Stn S1 in terms of light acclimation and biological interaction. In summary, this future climate change scenario will probably not affect the photosynthetic CO2 fixation and biomass of natural phytoplankton in Sanya Bay.

Secondary students’ ideas about scientific concepts underlying climate change

We present ideas about concepts underlying climate change, held by students in years 9 and 10. Misconceptions about climate change are common among students, and may be due to misconceptions about underlying concepts. To investigate this, we developed the Climate Change Concept Inventory (CCCI), and trialed it with 229 students; corroborating findings through focus group interviews. Our interview method and data analysis methods are described. Findings included overestimation of human contributions to atmospheric carbon inputs, ultra violet radiation in sunlight, and greenhouse gases in the atmosphere. Students were unaware that CO2 dissolves in water, and of the role of oceans in the carbon cycle. Greenhouse gases other than CO2 were rarely known. Earth’s energy balance and black body radiation were not well understood. There were misconceptions about interactions between electromagnetic radiation and atmospheric gases; and limited understanding of carbon chemistry. The CCCI is available from the corresponding author.

Clinical and histopathological study of actinic cheilitis

Abstract Introduction Actinic cheilitis is a inflammatory condition affecting mainly the lower lip and it is caused by chronic and excessive exposure of the lips to the ultraviolet radiation in sunlight. Objective Identifying clinical and histopathologic characteristics in 40 cases histopathologically diagnosed as actinic cheilitis. In addition, to investigate possible associations between these aspects. Method Defined as an observational, transversal, retrospective and descriptive study, it registered data regarding age, gender, occupation, symptomatology, records of sun exposure, frequency of sunblock use, tabagism, skin color, clinical aspect and histopathological classification. The data was submitted to the chi square test of Pearson (p<0.05). Result There was a predominance of male gender, leucodermia, and ages ranging between 50 and 60 years. The most common occupation was farming. From our sample, 85% had history of chronic sun exposure, in which 50% reported the use of some type of sunblock and only 25% were smokers. The main clinical condition was non-ulcerated leukoplakia and in the histopathological study, the hyperkeratosis were more common. A correlation between the degree of tissue alteration verified in the histopathological diagnosis and the studied clinical variables was not established (p=0.112). Conclusion The clinical aspect of the wound can conceal tissue alterations in different stages, emphasizing the importance of a premature diagnosis.

Concentration and pH-control on phosphoric acid treatment of zinc oxide for novel white pigment

ABSTRACTZinc oxide that has the photocatalytic activity is used as white pigment for cosmetics. A certain degree of sebum on the skin is decomposed by the ultraviolet radiation in sunlight. In this work, zinc oxide was shaken with 0.1, 0.2, and 0.5 mol/L of phosphoric acid at 50ºC for 3 hours to synthesize a white pigment for cosmetics. Zinc oxide was also set with 0.1 mol/L of phosphoric acid at pH 4, 5, 6, and 7, and then shaking. The chemical composition, powder properties, photocatalytic activity, color phase, and smoothness of the obtained powder were studied. The pH value in preparation had influence on the reaction between zinc oxide and phosphoric acid. The photocatalytic activity of zinc oxide was inhibited by phosphoric acid treatment. The obtained samples had enough high reflectance at the visible light region.

Integrative genetic analysis suggests that skin color modifies the genetic architecture of melanoma

Melanoma is the deadliest form of skin cancer and presents a significant health care burden in many countries. In addition to ultraviolet radiation in sunlight, the main causal factor for melanoma, genetic factors also play an important role in melanoma susceptibility. Although genome-wide association studies have identified many single nucleotide polymorphisms associated with melanoma, little is known about the proportion of disease risk attributable to these loci and their distribution throughout the genome. Here, we investigated the genetic architecture of melanoma in 1,888 cases and 990 controls of European non-Hispanic ancestry. We estimated the overall narrow-sense heritability of melanoma to be 0.18 (P < 0.03), indicating that genetics contributes significantly to the risk of sporadically-occurring melanoma. We then demonstrated that only a small proportion of this risk is attributable to known risk variants, suggesting that much remains unknown of the role of genetics in melanoma. To investigate further the genetic architecture of melanoma, we partitioned the heritability by chromosome, minor allele frequency, and functional annotations. We showed that common genetic variation contributes significantly to melanoma risk, with a risk model defined by a handful of genomic regions rather than many risk loci distributed throughout the genome. We also demonstrated that variants affecting gene expression in skin account for a significant proportion of the heritability, and are enriched among melanoma risk loci. Finally, by incorporating skin color into our analyses, we observed both a shift in significance for melanoma-associated loci and an enrichment of expression quantitative trait loci among melanoma susceptibility variants. These findings suggest that skin color may be an important modifier of melanoma risk. We speculate that incorporating skin color and other non-genetic factors into genetic studies may allow for an improved understanding of melanoma susceptibility and guide future investigations to identify melanoma risk genes.

Synthesis and powder properties of titanium—Zinc phosphate white pigments

AbstractPhotocatalytically active titanium dioxide and zinc oxide are used as a white pigment for cosmetics, leading to decomposition of a certain degree of sebum on the skin upon exposure to the ultraviolet radiation in sunlight. Herein, as novel white pigments for use in cosmetics, titanium‐zinc phosphates were prepared from titanium sulfate, zinc sulfates, and phosphoric acid. The chemical composition, powder properties, photocatalytic activity, color phase, smoothness, and acid resistance of the titanium‐zinc phosphates were evaluated. Samples prepared at high titanium ratio were easy to be amorphous phase, on the other hand, samples prepared at high zinc ratio indicated the X‐ray diffraction peaks of zinc phosphate dihydrate. The photocatalytic activity of these titanium‐zinc phosphate particles was low; thus these pigments should not induce decomposition of sebum on the skin. All samples prepared in this study exhibited high reflectance within the range of visible light. The substitution with titanium is effective to improve acid resistance of zinc phosphate white pigments.

SURFACE MODIFICATION OF TITANIUM DIOXIDE FOR NOBEL WHITE PIGMENT WITH CONDENSED PHOSPHORIC ACID TREATMENT

Photocatalytically active titanium dioxide is used as a white pigment in cosmetics. However, it may promote a certain degree of sebum decomposition on the skin exposed to ultraviolet radiation in sunlight. In this work, titanium dioxide was shaken with various condensed phosphate solutions to synthesize a novel white pigment for cosmetic applications. Titanium dioxide particles were added to various solutions at a P/Ti molar ratio of 1:1, and then shaken in water at 80oC for 1 h. The chemical composition, powder properties, photocatalytic activity, color phase, and smoothness of the produced powders were studied. The obtained materials exhibited the XRD peaks of titanium dioxide, although the peak intensities were weakened by the formation of a surface layer of titanium phosphate. These samples consisted of particles with sub-micrometer sizes, and the photocatalytic activity of the powders was reduced sufficiently to prevent the degradation of sebum on the skin. The suitable condensed phosphate for condensed phosphoric acid treatment of titanium oxide was sodium triphosphate from the whiteness and smoothness of powders.

Influence of pH-control in phosphoric acid treatment of zinc oxide

Abstract Zinc oxide is often used as a white pigment for cosmetics; however, it shows photocatalytic activity that causes decomposition of sebum on the skin when exposed to the ultraviolet radiation in sunlight. In this work, zinc oxide was reacted with phosphoric acid at various pH values to synthesize a novel white pigment for cosmetics. The chemical composition, powder properties, photocatalytic activities, colors, and smoothness of these pigments were studied. The obtained materials exhibited X-ray diffraction peaks relating to zinc oxide and phosphate after phosphoric acid treatment. The ratio of zinc phosphate to zinc oxide was estimated from inductively coupled plasma - atomic emission spectroscopy results. Samples treated at pH 4-7 yielded small particles with sub-micrometer sizes. The photocatalytic activity of zinc oxide became lower after phosphoric acid treatment. Samples treated at pH 4-7 showed the same reflectance as zinc oxide in both the ultraviolet and visible ranges. Adjustment of the pH was found to be important in the phosphoric acid treatment of zinc oxide.

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.

Temperature Dependence and P/Zn Ratio in Phosphoric Acid Treatment of Zinc Oxide

Zinc oxide, which has photocatalytic activity, is used as white pigment for cosmetics. A certain degree of sebum on the skin is decomposed by ultraviolet radiation in sunlight. In this work, zinc oxide was shaken with phosphoric acid to synthesize a white pigment for cosmetics. Zinc oxide was set with 0.1 mol/L of phosphoric acid at P/Zn = 1/1 and 1/2, and then shaking in hot water for 1 h. The chemical composition, powder properties, photocatalytic activity, color phase, and smoothness of the obtained powder were studied. The P/Zn ratio in preparation had an effect on the reaction between phosphoric acid and zinc oxide. The photocatalytic activity of zinc oxide was inhibited by phosphoric acid treatment. The obtained samples had enough high reflectance at the visible light region.

Influence of phosphate source on preparation of zinc phosphate white pigments

Photocatalytically active zinc oxide is used as a white pigment for cosmetics, leading to decomposition of a certain degree of sebum on the skin upon exposure to the ultraviolet radiation in sunlight. Herein, as novel white pigments for use in cosmetics, zinc phosphates were prepared from zinc nitrate and various phosphate compounds, viz., phosphoric acid, sodium di-hydrogen phosphate, di-sodium hydrogen phosphate, sodium pyrophosphate, or sodium triphosphate. The chemical composition, powder properties, photocatalytic activity, color phase, moisture retention, and smoothness of the zinc phosphates were evaluated. The obtained materials had Zn/P ratios corresponding to those of zinc orthophosphate Zn3(PO4)2, zinc pyrophosphate Zn2P2O7, and zinc triphosphate Zn5(P3O10)2. The photocatalytic activity of these zinc phosphate particles was low; thus, these pigments should not induce decomposition of sebum on the skin. All samples prepared in this study exhibited high reflectance within the range of visible light.

Influence of processing time in phosphoric acid treatment of titanium dioxide

Photocatalytically active titanium dioxide is used as a white pigment in cosmetics. However, it may promote a certain degree of sebum decomposition on the skin exposed to ultraviolet radiation in sunlight. In this work, titanium dioxide was shaken with phosphoric acid to synthesize a novel white pigment for cosmetic applications. Titanium dioxide particles were added to 0.5 mol/L of phosphoric acid at a P/Ti molar ratio of 1:2 with and without urea, and then shaken in hot water for 1, 3, 6 or 12 h. The chemical composition, powder properties, photocatalytic activity, colour phase and smoothness of the produced powders were studied. The obtained materials exhibited the X-ray diffraction peaks of titanium dioxide, although the peak intensities were weakened by the formation of a surface layer of titanium phosphate. These samples consisted of particles with sub-micrometre sizes, and the photocatalytic activity of the powders was reduced sufficiently to prevent the degradation of sebum on the skin. In addition, the shaking time affected the smoothness of the obtained materials. The treatment of titanium dioxide particles with phosphoric acid for 1 h is an effective method for inhibiting photocatalytic activity and allows the application of this material as a novel white pigment.

An Ultra-Violet Tolerant Wild-Type Strain of Melanin-Producing Bacillus thuringiensis.

Background:Bacillus thuringiensis is the most successful biological control agent used in agriculture, forestry and mosquito control. However, the insecticidal activity of the B. thuringiensis formulation is not very stable and rapidly loses its biological activity under field conditions, due to the ultraviolet radiation in sunlight. Melanin is known to absorb radiation therefore photo protection of B. thuringiensis based on melanin has been extensively studied.Objectives:The aim of this study was to find a wild type strain of naturally melanin-producing B. thuringiensis to avoid any mutation or manipulation that can affect the Cry protein content.Materials and Methods:Bacillus thuringiensis strains were isolated from soils of different States of Mexico and pigment extraction was followed by lowering the pH to 2 using 1N HCl. Pigment was characterized by some chemical tests based on its solubility, bleaching by H2O2 and flocculation with FeCl3, and using an Infrared (IR) spectrum. Ultraviolet (UV) irradiation experiment was performed to probe the melanin efficacy.Results:ELI52 strain of B. thuringiensis was confirmed to naturally produce melanin. The Cry protein analysis suggested that ELI52 is probably a B. thuringiensis subsp. israelensis strain with toxic activity against the Diptera order of insects. Ultra Violet protection efficacy of melanin was probed counting total viable colonies after UV radiation and comparing the results with the non-producing melanin strain L-DOPA (L-3, 4-dihydroxyphenylalanine) was also detected in the culture. ELI52 strain showed an antagonistic effect over some common bacteria from the environment.Conclusions:ELI52 wild-type strain of B. thuringiensis is a good bio-insecticide that produces melanin with UV-resistance that is probably toxic against the Diptera order of insects and can inhibit the growth of other environmental bacteria.

Influence of concentration in phosphoric acid treatment of titanium oxide and their powder properties

Titanium oxide that has the photocatalytic activity is used as a white pigment for cosmetics. A certain degree of sebum on the skin is decomposed by the ultraviolet radiation in sunlight. In this work, titanium oxide was shaken with various concentrations of phosphoric acid to synthesize a novel white pigment for cosmetics. Their chemical composition, powder properties, photocatalytic activity, color phase, and smoothness were studied. The obtained materials indicated XRD peaks of titanium oxide; however, these peak intensities became weak by phosphoric acid treatment. The photocatalytic activity of the obtained powders became weak by phosphoric acid treatment to protect the sebum on the skin. The high concentration of phosphoric acid was suitable to obtain a novel white pigment in the phosphoric acid treatment of titanium oxide.

Influence of pH-control in phosphoric acid treatment of titanium oxide and their powder properties

Titanium oxide that has the photocatalytic activity is used as a white pigment for cosmetics. A certain degree of sebum on the skin is decomposed by the ultraviolet radiation in sunlight. In this work, titanium oxide was shaken with phosphoric acid at various pH to synthesize a novel white pigment for cosmetics. Their chemical composition, powder properties, photocatalytic activity, color phase, and smoothness were studied. The obtained materials indicated XRD peaks of titanium oxide, however, these peak intensity became weak by phosphoric acid treatment. These samples without heating and heated at 100°C included the small particles with sub-micrometer size. The photocatalytic activity of the obtained powders became weak by phosphoric acid treatment at pH 4 and 5 to protect the sebum on the skin.

Temperature dependence and P/Ti ratio in phosphoric acid treatment of titanium dioxide and powder properties.

Titanium dioxide has photocatalytic activity and is used as a white pigment for cosmetics. A certain degree of sebum on the skin is decomposed by the ultraviolet radiation in sunlight. In this work, titanium dioxide was shaken with phosphoric acid to synthesize a white pigment for cosmetics. Titanium dioxide was treated with 0.1 mol/L of phosphoric acid at various P/Ti molar ratios, and then shaken in hot water for 1 h. The chemical composition, powder properties, photocatalytic activity, colour phase, and smoothness of the obtained powder were studied. The obtained materials indicated XRD peaks of titanium dioxide, however the peaks diminished subsequent to phosphoric acid treatment. The samples included small particles with sub-micrometer size. The photocatalytic activity of the obtained powders decreased, decomposing less sebum on the skin. Samples prepared at high P/Ti ratio with high shaking temperature indicated low whiteness in in L*a*b* colour space. The shaking and heating temperature and P/Ti ratio had influence on the smoothness of the obtained materials. Phosphoric acid treatment of titanium dioxide is an effective method to inhibit photocatalytic activity for a white pigment.