Ultraviolet Sunlight Research Articles

FIRST OBSERVATION IN THE SOUTH OF TITAN'S FAR-INFRARED 220 cm –1 CLOUD

An emission feature at 220 cm−1 which has been attributed to a cloud of condensed material in Titan's winter stratosphere has been seen for the first time in the south. This feature had previously been found only at high northern latitudes during northern winter and spring. The material emitting at 220 cm−1, as yet unidentified, may be volatiles associated with nitrile gases that accumulate in the absence of ultraviolet sunlight. Not detected as recently as 2012 February, the 220 cm−1 feature clearly appeared at the south pole in Cassini spectra recorded on 2012 July 24, indicating a rapid onset of the emission. This is the first indication of the winter buildup of condensation in the southern stratosphere that has been expected as the south pole moves deeper into shadow. In the north the 220 cm−1 feature continued to decrease in intensity with a half-life of 3 years.

Esssentials of Systemic Lupus Erythematosus

encounter patients with systemic lupus erythematosus (SLE). It is important to understand this chronic condition, its triggers, and current management strategies. Lupus erythematosus was a term first used to describe the skin abnormalities common to this disorder. We now know that SLE is an aberrant response by the human immune system; it is a multisystemic, autoimmune disease with many clinical and serological manifestations.1 The disease can affect every organ, particularly the kidneys, blood, and brain. The typical patient with lupus is a woman of childbearing age. The prevalence is greater in African American, Asian, and Hispanic populations. The 10-year survival rate is approximately 70%.2 The exact cause of SLE is unknown. Many triggers may be responsible for SLE. The genetic pattern has not yet been completely deciphered and is complex. It is likely that exposure to different environmental factors may determine if SLE will develop. Genetics and environmental factors may determine disease activity and severity. Certain environmental factors are known to affect individual who are genetically prone. These include ultraviolet light and sunlight, infections, and medications. Other factors that may trigger SLE development include hormones, smoking, and vaccines.1 SLE can be challenging to diagnose because of its diverse manifestations. Eleven diagnostic criteria have been established by the America College of Rheumatology. In order to make a formal diagnosis, 4 of the criteria summarized in Table 1 must be met.2 Common symptoms include rash, swollen and painful joints, fatigue, hair loss, photosensitivity, unexplained fever, and Raynaud’s phenomenon, a condition in which blood vessels in the fingers and toes spasm in cold temperatures. SLE symptoms may mimic numerous other medical problems. Symptoms may be intermittent and occur over months or years. Laboratory studies are an important part of the evaluation. Antinuclear antibody (ANA) and antiDNA tests are 2 useful antibody tests. The ANA test alone may not be helpful because many JNP

Effects of carbon nanomaterials fullerene C60 and fullerol C60(OH)18–22 on gills of fish Cyprinus carpio (Cyprinidae) exposed to ultraviolet radiation

In consequence of their growing use and demand, the inevitable environmental presence of nanomaterials (NMs) has raised concerns about their potential deleterious effects to aquatic environments. The carbon NM fullerene (C60), which forms colloidal aggregates in water, and its water-soluble derivative fullerol (C60(OH)18–22), which possesses antioxidant properties, are known to be photo-excited by ultraviolet (UV) or visible light. To investigate their potential hazards to aquatic organisms upon exposure to UV sunlight, this study analyzed (a) the in vitro behavior of fullerene and fullerol against peroxyl radicals (ROO) under UV-A radiation and (b) the effects of these photo-excited NMs on oxidative stress parameters in functional gills extracted from the fish Cyprinus carpio (Cyprinidae). The variables measured were the total antioxidant capacity, lipid peroxidation (TBARS), the activities of the antioxidant enzymes glutathione reductase (GR) and glutamate cysteine ligase (GCL), and the levels of the non-enzymatic antioxidant glutathione (GSH). The obtained results revealed the following: (1) both NMs behaved in vitro as antioxidants against ROO in the dark and as pro-oxidants in presence of UV-A, the latter effect being reversed by the addition of sodium azide, which is a singlet oxygen (1O2) quencher; (2) fullerene induced toxicity with or without UV-A incidence, with a significant (p<0.05) increase in lipid peroxidation (with greater damage under illumination), a decrease in GCL activity, and the depletion of GSH stocks (under illumination), all of which were attributed to 1O2 generation; and (3) fullerol also decreased GCL activity and GSH formation (p<0.05) but without lipid damage. The overall results show that fullerene can be toxic with or without light incidence, whereas UV radiation seems to play a key role in the environmental toxicity of carbon NMs through 1O2 formation.

Low temperature preparation and properties of high activity anatase TiO2 aqueous sols

Anatase TiO2 aqueous sols were prepared below 70°C by sol method. The influences of preparing conditions on the crystal structures and stability of the sols were investigated with X-ray diffraction and zeta potential. The photocatalytic activities of anatase TiO2 aqueous sols were characterised by degradation of methyl orange and methylene blue under ultraviolet light, fluorescent light and sunlight. The sols demonstrate higher photocatalytic activity than Degussa P25–TiO2.

DNA damage after acute exposure of mice skin to physiological doses of UVB and UVA light

Solar ultraviolet (UV) radiation is an important risk factor in skin carcinogenesis. This has been attributed mainly to the UVB waveband because the high-energetic photons are capable of interacting with DNA and inducing DNA damage. Recently, UVA light has also gained increasing interest in relation to DNA alteration. Although UVA photons are less energetic than UVB, they comprise a major fraction of sunlight UV radiation and penetrate deep into the skin. The study was carried out to compare the acute effects of UVA and UVB light on SKH-1 mice in relation to DNA damage and associated parameters. Mice were exposed to UVA (10 and 20 J/cm(2)) or UVB (200 and 800 mJ/cm(2)) radiation. The number of DNA single-strand breaks (SSB) in lymphocytes, amount of phosphorylated histone H2AX (gamma-H2AX) and apoptosis or DNA fragmentation (TUNEL-positive cells) in skin sections and level of gamma-H2AX, activated caspase-3 and phosphorylated p53 in skin were evaluated after 4 and 24 h. SSB analyzed by alkaline comet assay were found to be 4 and 24 h following UVB and UVA treatment, respectively. TUNEL and gamma-H2AX-positive cell were observed only in UVB exposed animals at both time intervals. The level of activated caspase-3 and phospho-p53 was increased 24 h after UVA and UVB radiation and was more apparent in UVB treated mice. The results indicate that the mechanism of DNA damage caused by acute UVA exposure includes formation of SSB (oxidative damage), but not double-strand breaks.

Are there mechanistic differences between ultraviolet and visible radiation induced skin pigmentation?

Most of the studies on sunlight-induced pigmentation of skin are mainly focused on ultraviolet (UV) radiation-induced pigmentation and ways to prevent it. Recent studies have shown that the visible component of sunlight can also cause significant skin pigmentation. In the current study, the extent of pigmentation induced by UV and visible regions of sunlight in subjects with Fitzpatrick skin type IV-V was measured and compared with pigmentation induced by total sunlight. The immediate pigment darkening (IPD) induced by the visible fraction of sunlight is not significantly different from that induced by the UV fraction. However, the persistent pigment darkening (PPD) induced by visible fraction of sunlight in significantly lower than that induced by the UV fraction. The dose responses of IPD induced by UV, visible light and total sunlight suggest that both UV and visible light interact with the same precursor although UV is 25 times more efficient in inducing pigmentation per J cm(-2) of irradiation compared to visible radiation. The measured diffused reflection spectra and decay kinetics of UV and visible radiation-induced pigmentation are very similar, indicating that the nature of the transient and persistent species involved in both the processes are also likely to be same.

Deleterious effects of light exposure on immunity and sexual coloration in birds

Summary1. Sunlight ultraviolet (UV) exposure can be highly damaging to biological tissues, being known to cause cellular damage and immunosuppression in humans and rodents, and depletion of carotenoid‐based sexual plumage coloration in birds (i.e. photobleaching). However, it remains unknown whether sunlight may cause photobleaching in living tissues that comprise sexual signals such as bare parts in birds. It seems possible that any carotenoids depleted from bare parts by sunlight could be replenished, but if so, this could impact the availability of carotenoids for other functions such as immunity and antioxidant defence. Such trade‐offs seem particularly likely in individuals that have a low dietary intake of carotenoids, or small amounts of carotenoids in body storage.2. We investigated the effects of exposure to simulated sunlight UV (UV+) on bill coloration, blood plasma and liver (i.e. body storage) carotenoids and pro‐inflammatory immune responses in male zebra finches (Taeniopygia guttata) in vivo, compared with individuals maintained in an identical environment but with the UV wavelengths removed by a filter (UV−). We also investigated whether any deleterious effects of UV exposure were mitigated by dietary carotenoid supplementation (UV+ Car+).3. Exposure to simulated sunlight UV was associated with low levels of carotenoids in liver, and elevated levels of carotenoids in blood plasma, suggesting the mobilisation of stored carotenoids. Simulated sunlight UV also caused impaired pro‐inflammatory immune responses, whereas this was not seen in carotenoid‐supplemented birds. We found no effects of simulated sunlight UV or carotenoid supplementation on oxidative damage in blood plasma or bill.4. Bill ‘carotenoid chroma’ diminished, and bill ‘UV chroma’ correspondingly increased, in all groups during the experiment (i.e. even in UV+ Car+ birds, and in UV− birds). This likely arose because the illuminance in the experimental cages was far higher than in standard laboratory housing conditions and suggests that carotenoid pigmentation is highly susceptible to photobleaching even under exposure to human‐visible wavelengths.5. These results highlight the potential for sunlight exposure to invoke a range of deleterious consequences for birds, including photobleaching and depression of immunity via pathways mediated by carotenoid allocation trade‐offs. The expression of carotenoid‐based sexual signals may therefore reveal an individual’s history of sunlight exposure and its deleterious effects on immunity.

The Study of Photogradation of Dichlorvos Pesticide Residues in Vegetables

This paper studies the photodegradation of dichlorvos pesticide residues in vegetables by ultraviolet excimer and direct sunlight. It was observed that the degradation of pesticide residues in vegetables conforms to the dynamic equation for pesticide degradation. The decomposition rate of the same concentration of organophosphorus pesticide was found to vary in different vegetables. This is attributed mainly to the pigments because chlorophyll pigments in different vegetables can stimulate the dichlorvos photodegradation. Through the uv excimer, the residual pesticide in the vegetable can be effectively removed in a short period of time, while the appears to be no adverse affects from this process. Therefore, it is possible to achieve a selective degradation of residual pesticides in vegetables through the use of uv excimers.

Increased fibroblast density in actinic cheilitis: association with tryptase‐positive mast cells, actinic elastosis and epithelial p53 and COX‐2 expression

Actinic cheilitis (AC) is characterized by epithelial and connective tissue alterations caused by ultraviolet sunlight overexposure known as photodamage. Fibroblasts have been linked to photodamage and tumor progression during skin carcinogenesis; however, their role in early lip carcinogenesis remains unknown. The aim of this study was to assess the density of fibroblasts in AC and normal lip (NL) samples and determine their association with markers of lip photodamage. Fibroblasts, mast cells, p53, COX-2, and elastin were detected in NL (n = 20) and AC (n = 28) biopsies using immunohistochemistry/histochemistry. Mast cell and fibroblast density and epithelial p53 and COX-2 expression scores were then obtained. Elastosis was scored 1-4 according to elastin fiber density and tortuosity. Fibroblasts, mast cells, p53, COX-2, and elastosis were increased in AC as compared to NL (P < 0.001). Multivariate analysis showed an association between fibroblast and mast cell density at the papillary and reticular areas of AC and NL (P < 0.05). Papillary fibroblast density was also associated with epithelial p53 and COX-2 expression (P < 0.05). Increased fibroblast density, both papillary and reticular, was found in the high elastosis group (scores 3-4) as compared to the low elastosis group (scores 1-2) (P < 0.01). Increased reticular mast cell density was detected only in the high elastosis group (P < 0.01). Fibroblasts are increased in AC, and they are associated with mast cell density, epithelial p53 and COX-2 expression, and actinic elastosis. Therefore, fibroblasts may contribute to lip photodamage and could be considered useful markers of early lip carcinogenesis.

Ultraviolet Sunlight Exposure During Adolescence and Adulthood and Breast Cancer Risk: A Population-based Case-Control Study Among Ontario Women

Recent studies suggest that vitamin D may be associated with reduced breast cancer risk, but most studies have evaluated only dietary vitamin D intake. The associations among ultraviolet radiation from sunlight, factors related to cutaneous vitamin D production, and breast cancer risk were evaluated in a population-based case-control study conducted in Ontario, Canada, between 2003 and 2004 (n = 3,101 cases and n = 3,471 controls). Time spent outdoors was associated with reduced breast cancer risk during 4 periods of life (>21 vs. ≤6 hours/week age-adjusted odds ratio (OR) = 0.71, 95% confidence interval (CI): 0.60, 0.85 in the teenage years; OR = 0.64, 95% CI: 0.53, 0.76 in the 20s-30s; OR = 0.74, 95% CI: 0.61, 0.88 in the 40s-50s; and OR = 0.50, 95% CI: 0.37, 0.66 in the 60s-74 years). Sun protection practices and ultraviolet radiation were not associated with breast cancer risk. A combined solar vitamin D score, including all the variables related to vitamin D production, was significantly associated with reduced breast cancer risk. These associations were not confounded or modified by menopausal status, dietary vitamin D intake, or physical activity. This study suggests that factors suggestive of increased cutaneous production of vitamin D are associated with reduced breast cancer risk.

Photodegradation of EDTA using Fenton’s reagent: a pilot-scale study

The presence of ethylenediaminetetraacetic acid (EDTA) in decontam- ination wastes can cause complexation of cations resulting in interferences in their removal by various treatment processes, for example chemical precipitation, ion exchange, etc., and can negatively affect the quality of the final form of the waste. Advanced oxidation processes using ozone, H2O2, ultrasonics (US), ultraviolet (UV) light, Fenton's reagent (Fe(II) ? H2O2), alone or in combination, are regarded as possible methods of clean and ecologically safe remedial treatment for the degradation of organics. In this study, the development of a column photoreactor (15 L) and a shallow-tank photoreactor (100 L) was carried out at the Centralised Waste Management Facility, Kalpakkam, India. Pilot-scale (batch) studies of the photocatalytic degradation of EDTA (20,000 mg/L) using UV ? Fenton's reagent in these reactor geometries were attempted. The effect of the power of the UV radiation on the kinetics of photodegradation of EDTA (20,000 mg/L) was studied using the column photoreactor. The shallow-tank reactor was used to study the photodegradation of EDTA (20,000 mg/L) using UV radiation, visible radiation, and sunlight. The successful use of sunlight as a source of energy and its greater effectiveness than UV radiation in the treatment of EDTA are presented.

Single Exposure of Human Oral Mucosa Fibroblasts to Ultraviolet B Radiation Reduces Proliferation and Induces COX-2 Expression and Activation

The lip vermillion constitutes a transition tissue, between oral mucosa and skin, where oral mucosal cells from epithelial and connective tissue compartments are exposed to ultraviolet (UV) sunlight. Fibroblasts are abundant resident cells of the connective tissue which are key regulators of extracellular matrix composition, as well as, epithelial and endothelial cell function. UVB light, an inherent component of sunlight, causes several alterations in skin fibroblasts, including premature senescence and increased cyclooxygenase COX-2 expression. To assess if UVB irradiation had similar effects on fibroblasts derived from human oral mucosa (HOM), primary cultures of HOM fibroblasts were irradiated with a single dose of 30 or 60mJ/cm2 of UVB light or sham-irradiated. Fibroblast proliferation was assessed from 3 to 48hrs after UVB-irradiation utilizing [3H]-thymidine incorporation and MTT assays. In addition, COX-2 mRNA expression was detected by RT-PCR, and PGE2 production was assessed using enzyme immunoassay from 0.5 to 24hrs after UVB-irradiation. The results showed a significant decrease in proliferation of UVB-irradiated HOM fibroblasts as compared to controls as measured by both [3H]-thymidine incorporation and MTT assays (p<0.001). HOM fibroblasts had increased COX-2 mRNA expression at 0.5 and 12hrs after irradiation, and PGE2 production was elevated at 12 and 24hrs post-irradiation as compared to controls (p<0.05). The results showed an inhibitory effect of a single dose of UVB irradiation on HOM fibroblast proliferation with an increase in COX-2 expression and activation. Therefore, photodamaged fibroblasts may play and important role in the pathogenesis of UV-induced lesions of the lip.

Light-Harvesting in n-ZnO/p-Silicon Heterojunctions

Zinc oxide (ZnO) films were deposited onto Si to form n-ZnO/p-Si heterojunctions. Under the illumination of by both ultraviolet (UV) light and sunlight, obvious photovoltaic behavior was observed. It was found that the conversion efficiency of the heterojunctions increased significantly with increasing thickness of the ZnO film, and the mechanism for light-harvesting in the heterojunctions is discussed. The results suggest that ZnO films may be helpful to increasing the harvesting of UV photons, thus decreasing the thermalization loss of UV energy in Si-based solar cells.

Photolysis, Oxidation, and Hydrolysis of 14C-Ethyl Prothiofos [O-(2, 4-Dichlorophenyl) O-Ethyl S-Propyl Phosphorodithioate

The chemical stability of the widely used organophosphorus insecticide 14C-prothiofos was studied. For this study prothiofos insecticide and some of its degradation products have been prepared. The oxon of the parent compound was obtained through the oxidation of the insecticide with various oxidizing agents, where yields depended on the type and nature of oxidizing agent. The effect of ultraviolet light and direct sunlight on prothiofos were investigated. Exposure to direct sunlight caused gradual degradation of prothiofos giving the same products as UV irradiation.The hydrolysis of 14C-prothiofos at pH 5, 7, 8, and 9 in buffered aqueous media at 25°C, 40°C and 55°C was studied. The results indicated that prothiofos was stable in acid medium, but it was hydrolyzed to 2,4-dichlorophenol and O-ethyl S-propyl phosphorodithioate in alkaline medium.The degradation products identified by TLC and GC/MS were prothiofos oxon, O-ethyl S-propyl phosphordithioate, des-propyl thioprothiofos, prothiofos oxon sulfoxide, and one unknown compound in addition to the parent compound. The phenolic compound was identified by GC/MS and by its color.Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

Accelerated weathering of polyaramid and polybenzimidazole firefighter protective clothing fabrics

Exposure to simulated ultraviolet sunlight at 50 °C and 50% relative humidity caused a significant deterioration in the mechanical performance of polyaramid and polyaramid/polybenzimidazole based outer shell fabrics used in firefighter jacket and pants. After 13 days of exposure to these conditions the tear resistance and tensile strength of both fabrics decreased by more than 40%. The polybenzimidazole containing fabric was less impacted by these conditions as it maintained approximately 20% more of its mechanical properties. These conditions also significantly degraded a water repellant coating on the fabric, which is critical to the water absorption performance of the outer shell fabrics. However, these conditions had little impact on the ultraviolet light protection of the outer shell as both fabrics still blocked 94% of ultraviolet light after 13 days of exposure. Confocal microscopy showed these conditions caused significant surface decomposition of and the switch from ductile to brittle failure of the polyaramid fibers. Cleavage of the amide linkages and the formation of oxidation species (as observed by Infrared spectroscopy) suggested these conditions caused photo-oxidation of the polyaramid fibers. There was little evidence of polybenzimidazole fiber degradation.

A simple photolithography method for microfluidic device fabrication using sunlight as UV source

A straightforward method for microfluidic devices fabrication using sunlight as the ultraviolet (UV) source is established in this work. This method is based on photolithography, but obviates the need for specialized UV exposure facility. Substrates coated with photoresist were placed directly under sun in a perpendicular direction to the sunlight for exposure. Exposure conditions were optimized for patterning features with different kinds of photoresist, photoresist of different thicknesses and dimensions. Exposure time can be adjusted to obtain designed features on a mask with good lateral structure according to the energy measured by UV meter (with a constant intensity of UV in sunlight). Masters produced under optimum exposure conditions were used for the fabrication of several microfluidic devices with different materials, structures, or functions. Resultant devices were shown eminently suitable for microfluidic applications such as electrophoretic separation, multiple gradient generator, and pneumatic valve-based cell culture. This photolithographic method is simple, low cost, easy to operate, and environmental friendly. Especially, the masters can be obtained in parallel simultaneously, which is suitable for chip fabrication for mass production. It is also more attractive for the laboratories, in which the support for photolithographic facility is not available.

Aging and photoaging

Skin aging is not a unique phenomenon but it is commonly divided into two different processes: chronological aging and photo-aging. Therefore we recognise two different phenotypes of skin aging. Chronological aging represents the structural, functional and metabolic changes in the skin that parallel the aging and degenerative changes in other body organs. Photo-aging is a consequence of oxidative damage due to overexposure to ultraviolet (UV) sunlight - both UVA and UVB (responsible for sunburn, basal and squamous cell carcinoma). Conditions of variable UV exposure may result from different latitudes, alteration of atmosphere, job (farmer towards bank employer), different behaviour to sun bathing [1]. A lot of different theories have been proposed to explain the phenomenon of aging. Many of them are interlinked. The deceleration of the mortality rate is one of the most intriguing recent findings in longevity research.

Carcinoma basocelular postraumático relacionado con pruebas epicutáneas

Basal cell carcinoma is the most common epithelial skin cancer in humans and usually effects elderly individuals. Although the pathogenesis is directly related to exposure to ultraviolet sunlight, other factors, particularly trauma, may be involved. We present the case of a woman with contact dermatitis due to sensitization to metals. She developed superficial basal cell carcinoma at the same site as a patch test—performed 30 months earlier—hat was strongly positive to 1 % gold chloride. In the histologic study with a scanning electron microscope, we detected electron-dense particles in the dermis which were subsequently identified as gold.

Ozone in the Gulf

ATMOSPHERIC SCIENCE Ozone is a secondary pollutant formed in the interactions of reactive carbon compounds, nitrogen oxides, and ultraviolet sunlight, with large potential impacts on the health of both animals and plants. Tropospheric ozone is a naturally occurring atmospheric species, but the highest concentrations are found in sunny areas with abundant air pollution, such as the Los Angeles basin in California. Lelieveld et al. analyze another area in which ozone pollution is severe—the Persian Gulf region. The locale possesses all of the ingredients for ozone production in abundance: intense air pollution (arriving from long distances as well as originating from strong local anthropogenic emissions), unusually vigorous stratospheric-tropospheric exchange, sparse deep convective mixing and precipitation, and copious sunlight. Using an atmospheric chemistry model, air-quality measurements, and support from satellite data, the authors predict and observe intense ozone pollution during the period from 1996 to 2006. Reducing the levels of ozone pollution in this region will depend largely on both decreasing the amounts of long-range pollution advected to the region and reducing local sources of nitrogen oxides. — HJS

Post-Traumatic Basal Cell Carcinoma Associated With Patch Testing

Basal cell carcinoma is the most common epithelial skin cancer in humans and usually effects elderly individuals. Although the pathogenesis is directly related to exposure to ultraviolet sunlight, other factors, particularly trauma, may be involved. We present the case of a woman with contact dermatitis due to sensitization to metals. She developed superficial basal cell carcinoma at the same site as a patch test—performed 30 months earlier—that was strongly positive to 1% gold chloride. In the histologic study with a scanning electron microscope, we detected electron-dense particles in the dermis which were subsequently identified as gold.