Intense Ultraviolet Radiation Research Articles

The impact of ultraviolet photography on the sun safety awareness and behavior of skiers and snowboarders

Objective: Snow sport enthusiasts, such as snowboarders and skiers, are a less studied population at significant risk for ultraviolet(UV) exposure due to long hours spent at high altitudes with more intense UV radiation. Studies have documented the efficacy ofUV photography to impact sun protection habits by individuals with a range of skin cancer risk factors. Informing snow sportenthusiasts of their sun damage through UV photography may be a way to change this population’s perception and behavior of sun protection.Methods: A UV camera was utilized at the 2013 SnowSports Industries America Snow Show in Colorado to assess the levelof accumulated sun damage in show attendees. A follow-up survey was performed at this same event one year later in 2014. Participants at the 2013 event were recruited to a UV camera booth and completed a ten-question pre-survey assessing baselinesun-safety awareness and behaviors. Full-face frontal photographs using two different UV camera models were then takenand shown on a digital screen to the participants. Individualized education was provided regarding the degree of sun damage revealed by the intervention as well as sun safety recommendations. Participants were at the 2013 event were then contacted viaemail six months later to complete a ten-question survey on surveymonkey.com. The survey assessed the permanence of the UV photography intervention on sun habits over the duration of the ski/snowboard season. Email was used for communication purposes after a poor response rate using telephone for a one-month post-intervention follow-up.Results: The 2013 post-intervention study revealed a 41% response rate (n=46) with overall positive influence of UV photographyon sun protection behavior in the survey. Post-intervention survey results for the 2014 study with an observed response rate of 28% (n=37) with a similar overall positive influence of our intervention on sun protection behavior.Conclusions: UV photography-based interventions and education may impact sun-safety behavior in high-risk populations such as skiers and snowboarders that may otherwise not receive appropriate education regarding the dangers of UV exposure and prevention of skin cancer. However, more controlled studies should be conducted to positively associate UV photography intervention and education and sun safety behavior.

Spatial distribution, temporal variation and risks of parabens and their chlorinated derivatives in urban surface water in Beijing, China

The occurrence and distribution of 13 target compounds, including eight parabens, four chlorinated parabens and p-hydroxybenzoic acid (PHBA), were detected in surface water samples at 35 sampling sites in the Beijing River system, China. The surface water samples were collected from the main rivers and lakes in the urban area monthly from July 2013 to June 2014 (except the frozen period). Laboratory analyses revealed that parabens were ubiquitous in the surface water of Beijing. PHBA was the predominant compound in the surface water samples, with the average concentration of 239ngL−1, followed by the total amount of chlorinated parabens (average 50.1ng/L) and parabens (average 44.3ng/L). It is noteworthy that octylparaben with longer chain was firstly detected in the surface water. Significant difference was observed for paraben concentrations from different sampling sites, and the highest level of parabens was found in the Xiaotaihou River, which was mainly due to the untreated sewage discharge. Seasonal variation of target compounds in the urban surface water was also studied, and parabens exhibited a different temporal variation from chlorinated derivatives. A combination of factors including high residual chlorine level and water temperature as well as intense ultraviolet radiation might enhance the persistence of chlorinated parabens in chlorinated water during the wet season. Risk assessment showed that parabens and their chlorinated derivatives are not likely to produce biological effects on aquatic ecosystems at current levels in the surface water of Beijing.

Light detonation wave in a cylindrical Z-pinch

A secondary compression wave previously observed by other researchers in a cylindrical Z-pinch has been identified in this work as a light detonation wave. It appears on the inner surface of a discharge chamber under the action of the intense ultraviolet radiation from a plasma pinch at the stage of its maximum compression. The condition of the light detonation wave has been determined experimentally. The dependence of its Mach number on a generalized dimensionless variable has been determined taking into account the conservation laws for the light detonation wave including the pressure of the gas, expenses on the formation of the surface plasma, and the energy of ionization of the gas involved in the wave. An analogy with the laser-supported detonation wave created by intense laser radiation has been revealed. The indicated dependence is within the error of measurement in agreement with the experimental data for light detonation waves created by both methods.

Photocatalytic odor abatement by platinized TiO2 under optically transmitted LED–UV light

Combined use of platinized titania and light emitting diode (LED) ultraviolet (UV) illumination was explored for photocatalytic odor abatement with carbon disulfide (CS2) as model odorant. Noble metal deposition on anatase titanium dioxide (TiO2) surface was achieved by UV assisted photoreduction of platinum (Pt). Solid-state and elemental analyses show that surface platinized (Pt/TiO2) and bare (TiO2) titania, while of comparable bulk structural properties, differ in light absorption and surface characteristics as a result of the photodeposited Pt. The effect of distance and collimation was modeled to predict the impact of position of UV source and collimation on UV radiation intensity and distribution on photocatalyst surface. Increased radiation intensity due to minimized divergence with collimated LED–UV has improved output beam intensity, resulting in enhanced photoreaction rates regardless of photocatalyst used. Fitting of batch experimental data into classical Langmuir–Hinshelwood (L–H) kinetic model yielded higher model parameter values with Pt/TiO2 than TiO2 as well as the calcined counterparts. Lower number of surface OH groups and better charge carrier separation in calcined and/or Pt surface treated titania were proposed as main factors underpinning enhanced reaction rates and photonic efficiencies. Data fitting into a pseudo-steady-state L–H kinetic model has returned higher optimized fit parameter values with Pt/TiO2 than TiO2 while showing a nonlinear power law relationship between irradiation intensity and reaction rate. Results of fluorescence excitation-emission (EEM) spectroscopy and infrared (IR) thermography corroborate the occurrence of localized surface plasmon resonance (LSPR) effects such as subdued fluorescence and localized heating. By employing plasmonic photocatalysts and innovative delivery of photoradiation, this study has presented a case of a straightforward approach to environmental odor abatement based on affordable and widely available UV–LEDs and titania support.

Diel vertical migration, size distribution and photoprotection in zooplankton as response to UV‐A radiation

AbstractThe transparency regulator hypothesis (TRH) proposes that ultraviolet radiation (UVR) is a main driving force behind diel vertical migration (DVM) of zooplankton in clearwater systems. While previous studies have mainly studied DVM in relation to the TRH on a spatial scale across systems we here focus on long‐term trends in a single system in order to assess if UVR explains observed patterns in DVM. We show that the strength of DVM in Daphnia is to a large extent explained by UVR and we demonstrate a tipping point at which the UVR intensity drastically affects the strength of DVM in Daphnia. In contrast, the strength of DVM could not be explained by the level of UVR among calanoid copepods. The amount of photoprotective compounds did not differ between zooplankton found at different depths indicating that zooplankton do not change their vertical position in relation to the amount of accumulated photoprotective compounds. In addition, we show that both Daphnia and calanoid copepods display patterns of size structured migration.

An 800‐year ultraviolet radiation record inferred from sedimentary pigments in the Ross Sea area, East Antarctica

High performance liquid chromatography (HPLC) combined with mass spectrometry (MS) was used to analyse deposited pigments (including chlorophyll a, phaeophytin a, canthaxanthin, echinenone, zeaxanthin, scytonemin and mycosporine‐like amino acids) from two sediment profiles of ponds in the Ross Sea area, East Antarctica. We explored the sources and characteristics of each pigment, reconstructed an 800‐year record of ultraviolet radiation (UVR) and total incoming light intensity, and identified the possible factors that may have influenced historical UVR changes in this region. The results indicated at least four UVR peaks during the past 800 years, corresponding to c. AD 1950–2000, 1720–1790, 1560–1630 and 1350–1480, with the intensity from the most recent sediments being the highest. A comparison between the changes in UVR and total incoming light intensity showed similar patterns between AD 1720 and 1830, suggesting that factors controlling the UVR intensity in the Ross Sea area may be related to insolation fluctuation at that time. The two proxies are, however, weakly correlated during other periods. Historically, there is a relationship between the reconstructed UVR and solar activity, but this natural process may be strongly affected by multiple factors, including climate parameter change and anthropogenic activities during the modern times.

Skin pigmentation variation among populations of West Maharashtra, India.

Global patterns of skin pigmentation have evolved as an adaptation to local ultraviolet radiation (UVR). Indian populations exposed to intense UVR show great variation in skin pigmentation. The UVR-based selection model cannot satisfactorily address the high prevalence of light skin among these populations. Thus, the present study examines pigmentation variation among populations of West Maharashtra and the Indian subcontinent within the context of population structure and social hierarchy. Melanin index (MI) was measured from 555 individuals representing six endogamous populations of West Maharashtra. Skin pigmentation was assessed in terms of variation between populations and differences between and among castes and tribes. A linear regression analysis was run to assess the relationship among MI, UVR, and social hierarchy using published MI data from 13 Indian endogamous populations. Skin pigmentation differed significantly among populations of West Maharashtra. Significant pigmentation variation exists between castes and tribes of West Maharashtra as well as across the Indian subcontinent. We observe a significant negative relationship between social hierarchy and skin pigmentation, whereas the relationship between UVR and MI is weak. Our results suggest that various factors may have contributed to pigmentation diversity across the Indian subcontinent. The lack of correlation between UVR and MI suggests that natural selection may not have played a significant role in shaping pigmentation variation across the subcontinent. We discuss other possible explanations, including metabolic conservation and cultural factors such as traditional social hierarchies and strict endogamy that have led to the development of population structure.

Modeling TiO2 nanoparticle phototoxicity: The importance of chemical concentration, ultraviolet radiation intensity, and time

As a semiconductor with wide band gap energy, TiO2 nanoparticles (nano-TiO2) are highly photoactive, and recent efforts have demonstrated phototoxicity of nano-TiO2 to aquatic organisms. However, a dosimetry model for the phototoxicity of nanomaterials that incorporates both direct UV and photo-activated chemical toxicity has not yet been developed. In this study, a set of Hyalella azteca acute toxicity bioassays at multiple light intensities and nano-TiO2 concentrations, and with multiple diel light cycles, was conducted to assess how existing phototoxicity models should be adapted to nano-TiO2. These efforts demonstrated (a) adherence to the Bunsen-Roscoe law for the reciprocity of light intensity and time, (b) no evidence of damage repair during dark periods, (c) a lack of proportionality of effects to environmental nano-TiO2 concentrations, and (d) a need to consider the joint effects of nano-TiO2 phototoxicity and direct UV toxicity.

Effect of layered double hydroxides on ultraviolet aging resistance of SBS modified bitumen membrane

Layered double hydroxides (LDHs)/styrene-butadiene-styrene (SBS) copolymer modified bitumen was prepared by melt blending. The effect of LDHs on the ultraviolet (UV) aging behavior of SBS modified bitumen was investigated. The changes of chemical structures of modified bitumen before and after UV aging were characterized by Fourier transform infrared spectroscopy (FTIR). The results show that LDHs obviously reduce the variation of softening point and low temperature flexibility of SBS modified bitumen under different UV radiation intensities, which indicates that the UV aging resistance performance of SBS modified bitumen is improved effectively by LDHs. Compared with SBS modified bitumen, the changes of carbonyl, sulfoxide and butadienyl of LDHs/SBS modified bitumen decrease significantly after UV aging according to FTIR analysis, demonstrating that the oxidation and degradation reactions of SBS modified bitumen were restrained effectively by adding LDHs.

Hydrogen Therapy Reduces Oxidative Stress-associated Risks Following Acute and Chronic Exposure to High-altitude Environment

Low pressure, low oxygen concentration, and intense ultraviolet (UV) radiation in high-altitude environments, can cause oxidative stress which can trigger mountain sickness. A recent study demonstrated that hydrogen gas with a good permeability in biological membranes can treat various disorders by exerting its selective anti-oxidation and anti-inflammatory effects, indicating that hydrogen therapy plays a role in scavenging free radicals and in balancing oxidation and anti-oxidation systems of cells. Therefore, we hypothesize that inhaling low-dose hydrogen or drinking hydrogen-saturated water is a novel and simple method to prevent and treat oxidative stress injury caused by low pressure, low oxygen concentration and intense UV radiation in plateaus, thus reducing the risk of mountain sickness.

Update on ultraviolet A and B radiation generated by the sun and artificial lamps and their effects on skin.

Solar radiation, especially ultraviolet A (UVA) and ultraviolet B (UVB), can cause damage to the human body, and exposure to the radiation may vary according to the geographical location, time of year and other factors. The effects of UVA and UVB radiation on organisms range from erythema formation, through tanning and reduced synthesis of macromolecules such as collagen and elastin, to carcinogenic DNA mutations. Some studies suggest that, in addition to the radiation emitted by the sun, artificial sources of radiation, such as commercial lamps, can also generate small amounts of UVA and UVB radiation. Depending on the source intensity and on the distance from the source, this radiation can be harmful to photosensitive individuals. In healthy subjects, the evidence on the danger of this radiation is still far from conclusive.

Solar exposure(s) and facial clinical signs of aging in Chinese women: impacts upon age perception.

A new reference clinical atlas of facial signs dedicated to photoaging was applied to 301 Chinese women of various ages through standardized photographs. Such approach aimed at better describing the facial changes induced by both real/chronological age and sun exposure and their respective impact on two subcohorts of different behavior with regard to sun exposure. A total of 28 various facial signs were individually graded according to their severity by a panel of experts, and a perceived apparent age of each subject was assessed. Results showed that the severity of major signs significantly increased rather linearly with age, with a higher rate in sun-exposed subjects as compared with subjects who regularly avoid sun exposure. The severity of facial signs, all impacted by sun exposure, better correlated with perceived apparent age than real/chronological age. The protocol used in the present work, similar to that previously applied to two cohorts of French women, assigned a greater impact of sun exposure in the facial aging signs of Asian women – all clinical signs are influenced by extrinsic factors – as compared with Caucasian women of comparable ages, likely related to much more intense ultraviolet (UV) radiation.

Investigation of TiO 2 /zeolite photocatalytic activity for Safranin dye removal of aqueous solution

Aims: This study was aimed to determine the TiO 2 /zeolite photocatalytic activity for removing red Safranin dye form aqueous phase. Materials and Methods: In this study, TiO 2 nanoparticles were produced using sol-gel method and 2.5 ml sol-gel was coated on 1.2222 g of zeolite. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were applied to specify the structure and morphology of TiO 2 nanoparticles. The effect of TiO 2 coating on zeolite, ultraviolet (UV) radiation intensity, initial concentration of dye and the type of photocatalyst substrate (fixed and moving) on photocatalytic process was investigated. Results: According to XRD results, the TiO 2 nanoparticles had two phases including anatase (80.5%) and rutile (19.5%). The uniformity of nanoparticles was obvious in the SEM images. The removal efficiency of TiO 2 coated on zeolite was higher than TiO 2 photocatalysis with increasing UV radiation intensity from 2.4 w/m 2 to 3.9 w/m 2 , the photocatalytic efficiency was also enhanced. The removal efficiency decreased from 91.61% to 77.91% by increasing the red Safranin dye concentration from 10 mg/L to 50 mg/L. The moving bed of TiO 2 /zeolite photocatalyst had a higher efficiency than the fixed bed. Conclusion: In over all, the TiO 2 /zeolite photocatalyst was much more effective than TiO 2 photocatalyst for Safranin dye removal from the aqueous phase. With increasing UV radiation intensity and decreasing dye concentration photocatalytic efficiency, was improved. TiO 2 /zeolite photocatalyst with fixed bed is recommended to be used in water treatment. The most important problem of using moving-bed TiO 2 /zeolite photocatalyst in the water treatment is opacity.

Факторы, влияющие на эффективность каталитической очистки воздуха от загрязнителей

In the article, the influence of the intensity of ultraviolet radiation to the media photocatalytic air purification. Conducted research and made a choice of material based on its durability performance, resistance and efficiency of air purification. It is noted that the substrate can be nonwoven materials, glass balls of various size, porous ceramics, paper, etc. Defined methods of applying the photocatalyst to the carrier material. Designed and manufactured experimental setup to determine the static resistance to air flow. Reviewed the design of the experimental setup to determine the static resistance to air flow. Based on the obtained results we note that the minimum resistance to any air flow creates a synthetic non-woven material based on polyethylene terephthalate. Nonwoven fabric based on natural wool keeps the particles of photocatalyst and creates a relatively small resistance at high speed air flow. Media made from sintered glass beads do not lose the nanoparticles at any speed of flow.

Wavelet Characterization of Ozone Layer Depletion for Atmospheric Region of Pakistan

Ozone is of considerable importance to mankind because of its role as a shield for the biosphere against the Ultraviolet (UV) radiation from the outer space, in particular from the sun. In the recent years the advancement in the science and technology has increased the understanding of various phenomena of the environment and consequently the predictability of many naturally occurring events. It has been Due to a serious reduction of O3 content in the atmosphere life-forms on the earth are exposed to a new hazard in the form of an increase of harmful solar UV radiation intensity at the sea level. Obviously, this situation calls for an assessment, monitoring and prevention of the incidence of decrease in the O3 concentration. The fluctuating dynamics of stratospheric ozone layer depletion (OLD) for Pakistan atmospheric region has been introduced by mentioning the production and annihilation of ozone. The recent development in the theory and application of wavelets are yielding powerful multi resolution techniques for the analysis of time series and image data. Wavelets are the central idea of a broad framework for displaying and analyzing data. Wavelets possess a simultaneous time–frequency localization that makes them useful in presenting complicated signals. In this communication behaviour of ozone is explained on the basis of ozone profile, effects of periodic, a-periodic change along with effects of monthly and seasonal variations using wavelet analysis.

Effects of ultraviolet radiation on marine primary production with reference to satellite remote sensing

Incubation experiments have shown that ultraviolet radiation (UVR) has significant influences on marine primary production (MPP). However, existing satellite remote sensing models of MPP only consider the effects of visible light radiation, ignoring the UVR. Additionally, the ocean color satellite data currently used for MPP estimation contain no UV bands. To better understand the mechanism of MPP model development with reference to satellite remote sensing, including UVR’s effects, we first reviewed recent studies of UVR’s effects on phytoplankton and MPP, which highlights the need for improved satellite remote sensing of MPP. Then, based on current MPP models using visible radiation, we discussed the quantitative methods used to implement three key model variables related to UVR: the UVR intensity at the sea surface, the attenuation of UVR in the euphotic layer, and the maximum or optimal photosynthetic rate, considering the effects of UVR. The implementation of these UVR-related variables could be useful in further assessing UVR’s effects on the remote sensing of MPP, and in reevaluating our existing knowledge of MPP estimation at large spatial scales and long-time scales related to global change.

Comparison of ultraviolet (UV) radiation intensity between a single lamp and a double lamp in a reactors

Disinfection of drinking water is a challenging and controversial issue. Chemical and ultraviolet (UV) methods are used to deactivate bacteria. Some of the chemical disinfection causes threats to public health since they produce toxic chemical compounds. Recently, several researchers conducted experiments and mathematical models to deactivate pathogenic bacteria from wastewater and drinking water using UV. The intensity of UV is very effective in deactivating bacteria. The authors compared the radiation intensity of a single and double lamp in a UV reactor for water treatment using computational fluid dynamics. The results indicated that the mean volume emission rate of single lamp and double lamp in the reactor was similar. However, the energy distribution of single lamps was much better than the double lamp in the reactor. The sensitivity analysis using three different UV transmittances (UVT), 70, 80 and 90%, indicated that the increase in % UVT value improved the energy distribution in the UV reactor.

Broadband and omnidirectional highly-transparent coverglasses coated with biomimetic moth-eye nanopatterned polymer films for solar photovoltaic system applications

Highly-transparent coverglasses coated with broadband and omnidirectional antireflective (AR) moth-eye nanopatterned ultra-violet (UV) curable polymer, i.e., Norland Optical Adhesive (NOA) 63, films are reported. The moth-eye nanopatterns on the NOA63 polymer films/glasses are transferred from the silicon molds with conical nanogratings (NGs) using poly-dimethylsiloxane stamps by a soft imprint lithography technique. For the NOA63 NGs/glasses, surface wetting behaviors, UV radiation/thermal effects, and optical properties, together with theoretical analyses using rigorous coupled-wave analysis calculations, are investigated. For a period of 380nm, the NOA63 NGs/glass exhibits a hydrophobic surface with a water contact angle of ~112°. Furthermore, it increases the transmittance of the bare glass over a wide range of wavelengths and incident light angles, showing the higher solar weighted transmittance (TSW) of ~93.2% at an incident angle (θi) of 0° and the larger average TSW value of ~83.6% at θi=10–70° than those (i.e., TSW~90.1% at θi=0° and average TSW value of ~81.5% at θi=10–70°) of the bare glass in the wavelength range of 350–1800nm. In addition, it shows a relatively good stability under intense UV radiation and high temperature. By employing the 380nm-period NG patterned NOA63 films into an AR coating of coverglasses in encapsulated III-V GaInP/GaInAs/Ge triple-junction solar photovoltaic (PV) sub-receiver modules, an enhanced power conversion efficiency (PCE) of 31.33% is obtained mainly due to an increased short-circuit current density (JSC) of 14.68mA/cm2 compared to reference PV modules with the bare coverglass (i.e., PCE=30.12% and JSC=14.07mA/cm2) at θi=0°. For incident angle-dependent PV module characteristics, it also has more outstanding solar energy conversion properties in a wide θi range of 10–70°.

Preparation and thermo-optical characteristics of a smart polymer-stabilized liquid crystal thin film based on smectic A–chiral nematic phase transition

A smart polymer stabilized liquid crystal (PSLC) thin film with temperature-controllable light transmittance was prepared based on a smectic-A (SmA)–chiral nematic (N*) phase transition, and then the effect of the composition and the preparation condition of the PSLC film on its thermo-optical (T-O) characteristics has been investigated in detail. Within the temperature range of the SmA phase, the PSLC shows a strong opaque state due to the focal conic alignment of liquid crystal (LC) molecules, while the film exhibits a transparent state result from the parallel alignment of N* phase LC molecules at a higher temperature. Importantly, the PSLC films with different temperature of phase transition and contrast ratio can be prepared by changing the composition of photo-polymerizable monomer/LC/chiral dopant. According to the competition between the polymerization of the curable monomers and the diffusion of LC molecules, the ultraviolet (UV) curing surrounding temperature and the intensity of UV irradiation play a critical role in tuning the size of the polymer network meshes, which in turn influence the contrast ratio and the switching speed of the film. Our observations are expected to pave the way for preparing smart PSLC thin films for applications in areas of smart windows, thermo-detectors and other information recording devices.

Camelid genomes reveal evolution and adaptation to desert environments.

Bactrian camel (Camelus bactrianus), dromedary (Camelus dromedarius) and alpaca (Vicugna pacos) are economically important livestock. Although the Bactrian camel and dromedary are large, typically arid-desert-adapted mammals, alpacas are adapted to plateaus. Here we present high-quality genome sequences of these three species. Our analysis reveals the demographic history of these species since the Tortonian Stage of the Miocene and uncovers a striking correlation between large fluctuations in population size and geological time boundaries. Comparative genomic analysis reveals complex features related to desert adaptations, including fat and water metabolism, stress responses to heat, aridity, intense ultraviolet radiation and choking dust. Transcriptomic analysis of Bactrian camels further reveals unique osmoregulation, osmoprotection and compensatory mechanisms for water reservation underpinned by high blood glucose levels. We hypothesize that these physiological mechanisms represent kidney evolutionary adaptations to the desert environment. This study advances our understanding of camelid evolution and the adaptation of camels to arid-desert environments.