Levels Of Ultraviolet Radiation Research Articles

Ultraviolet antireflectance and high energy facets induced superhydrophilicity in SnO2 nano-arrayed thin films

Ultraviolet (UV) radiation carries higher energy than visible light which causes potential damages to eye, immune system and skin. Even though antireflective glasses available in market are effective against visible light, they reflect high levels of UV radiation. Hence development of coatings which neither transmit nor reflect high energy UV radiation is highly desirable. Herein, we demonstrate the direct growth of SnO2 nanostructured arrays with broadband antireflectance using a simple spray pyrolysis method. An investigation on nanostructure evolution has been carried out which revealed that the growth mechanism has a strong dependence on deposition temperature, time and solvent used. SnO2 nanostructured arrays exhibited broadband antireflectance with less than 0.5% reflectance and near zero transmittance in high energy UVB (280–315 nm) wavelength region due to the graded refractive index and scattering provided by nanoarrays. The prepared samples are superhydrophilic in nature due to the presence of high energy facets which account for their observed anticondensation properties. These multifunctional SnO2 nanostructured arrays may have potential applications in sunglasses, safety glasses, windows, optical materials and solar panels owing to their antireflective, antifogging and self-cleaning properties.

Epidemiological variations and trends in health burden of glaucoma worldwide.

To evaluate the trends and variations in global health burden of glaucoma by year, age and sex, region and socio-economic status, using disability-adjusted life years (DALYs). The DALY numbers, crude DALY rate and age-standardized DALY rate globally and in each country were obtained the GBD 2015 study database. The corresponding human development index (HDI) and gross domestic product (GDP) per capita were obtained from the United Nations and World Bank. Environmental data were obtained from the WHO Global Health Observatory data repository. From 1990 to 2015, the DALY number and age-standardized DALY rate due to glaucoma increased by 122% and 15%, respectively. Both male and female showed similar increasing trend with ageing, with the peak at 60years old and increasing again since 75years old. Sex disparities in DALY number were noted, with higher burden among female than male in each age group (all p<0.001). The health burden of glaucoma was substantial unequal, with Gini coefficient of 0.865 for DALY number, 0.235 for crude DALY rate and 0.254 for age-standardized DALY rate, respectively. The age-standardized DALY was significantly associated with HDI, accounting for 22.2% variance across countries (R2 =0.222,p<0.001). Similarly, the GDP per capita was inversely associated with age-standardized DALY rate but can explain only 10.6% variations in age-standardized DALY rate (R2 =0.106,p<0.001). The age-standardized DALY rate due to glaucoma was positively associated with national levels of ultraviolet radiation and PM2.5 . The health burden of glaucoma continuously increased in the past 25years and distributed unequally. Lower socio-economic level, older age, female, higher ambient ultraviolet radiation and higher level of air pollution were significantly associated with higher burden of glaucoma.

Physiological response of the toxic and non-toxic strains of a bloom-forming cyanobacterium Microcystis aeruginosa to changing ultraviolet radiation regimes

Microcystis aeruginosa, a common bloom-forming cyanobacterium with both non-toxic and toxic strains, experiences a variable light environment due to buoyancy regulation and the variable mixing of the water columns. However, little is known on how non-toxic and toxic strains respond to changing photosynthetically active radiation (PAR) and ultraviolet radiation (UVR). Here, the non-toxic and toxic strains of M. aeruginosa were exposed to simulated solar radiation for 6 h, and their physiological changes were investigated at different irradiance levels of UVR (295–400 nm) in combination with PAR (400–700 nm). Our results showed that UVR at each level resulted in a larger inhibition on the maximum photochemical yield of Photosystem II (PSII) in the toxic strain. The non-toxic strain showed a quicker rise in the non-photochemical quenching when PAR + UVR were below 40.8 + 5.0 W m−2 and higher exopolysaccharide content at each radiation level, while the toxic strain exhibited stronger recovery capacity and superoxide dismutase (SOD) activity compared with the non-toxic strain, particularly for cells treated in the presence of UVR. In addition, UVR induced much higher content of microcystin in the toxic strain with the increase of irradiance levels, but decreased it when UVR was higher than 7.3 W m−2. Although UVR led to growth inhibition in both strains, the toxic strain showed much higher specific growth rate under UVR in comparison with the non-toxic strain. Our results indicate that the toxic strain has a competitive advantage relative to the non-toxic strain in a changing light environment with increase of UVR and PAR via stronger antioxidant capacity (higher SOD activity and the synthesis of microcystin) and quicker PSII recovery capacity.

Chemical profiling of mycosporine-like amino acids in twenty-three red algal species.

Rhodophyta produce a variety of chemically different mycosporine‐like amino acids (MAAs), compounds that are known as some of the strongest ultraviolet (UV) absorbing molecules in nature. Accordingly, they primarily act as photoprotectants against harmful levels of solar ultraviolet radiation in the UV‐A and UV‐B range. In order to get a deeper understanding of the chemical diversity of MAAs in red algae, pure standards of eleven mycosporine‐like amino acids were isolated from three different species (Agarophyton chilense, Pyropia plicata and Champia novae‐zelandiae) using various chromatographic methods. Their structures were confirmed by nuclear magnetic resonance and mass spectrometry. Four out of the eleven MAAs are reported for the first time in algae. In addition, a new high‐performance liquid chromatography method was developed for the separation of all isolated MAAs and successfully applied for the analysis of twenty‐three red algal species of marine origin. All of them contained MAAs, the most abundant compounds were shinorine, palythine, asterina‐330 and porphyra‐334. For some samples, the direct assignment of MAAs based on their UV spectra was not possible; therefore, the target analytes were enriched by a simple concentration step, followed by liquid chromatography‐mass spectrometry analysis of the extracts. This approach enabled a deeper insight into the MAA pattern of red algae, indicating that not only the four dominant ones are synthesized but also many others, which were often described as unknown compounds in previous studies.

Quantification of ultraviolet (UV) radiation in the shade and in direct sunlight

Ultraviolet (UV) radiation is associated with negative health effects, including sun damage and skin cancer. The purpose of this study is to compare the protective effects of the shade provided by a sun umbrella versus that provided by a tree. Sun sensors that register the level and dose of UV radiation were placed in the shade and in direct sunlight. Measurements were recorded every half hour between the hours of 12:30 p.m. and 3:00 p.m. in Sacramento, California. The results suggest that the level of UV radiation in the shade is not zero. The sensors located in tree shade indicated that over 5% of UV radiation was detected in the shade. The sensors located in sun-umbrella shade showed that greater than 17% of UV radiation reached the shade. The sun sensors used in our study collected UV radiation data relevant to UV index; however, they did not differentiate between UVA, UVB, visible, and infrared light. The amount of UV radiation detected in the shade is not zero, thus regular sunscreen use and other sun protective practices should be followed to reduce the risk of sun damage and skin cancer.

Water Ice in AGN and Starbursts

Complex chemical species are easier formed in a solid phase, for example in a mixture of ices of water, carbon oxides, methane, ammonia, methanole and other, less abundant molecules. Ultraviolet photons in the range 5 - 13.6 eV and the charged particles with MeV-GeV energies serve as an energy source of reactions. Icy particles containing mentioned substances, can exist only in internal areas of the interstellar molecular clouds protected from influence of external ultraviolet radiation. However cosmic rays are capable to penetrate in clouds and to cause an irradiation of ices by means of secondary ultra-violet photons necessary for initiation of chemical reactions of complexisation. In this work a survivability of ices under harsh conditions of active galaxies is discussed. Preliminary model calculations show that abundances of ices depend not only on ionization parameters of the clouds but also on the shape of incident radiation that is on presence and level of hard ultraviolet and X-ray radiation. The last circumstance is directly related to the radiation of the accretion disk of galaxies with active nuclei and can be used to classify active galaxies, for example to distinguish starburst galaxies from those with active nuclei.

Assessment of knowledge and attitude towards sun exposure and photoprotection measures among Indian patients attending dermatology clinic

Background: Many skin diseases are known to be either initiated or aggravated by excessive ultraviolet (UV) exposure. High cumulative levels of UV radiation may lead to tanning, burning, photoaging, photoallergic and phototoxic reactions, immunosuppression, and even skin cancers. Many international studies have found that the level of knowledge, attitudes, and practices of the general public toward sun exposure and sun protection measures is good in the Western countries, especially in countries with high incidence of skin cancers compared to Asian countries and Middle East. In India, the incidence of skin cancer is not very high, but UV exposure has definitely increased in the past few decades. Little is known about the knowledge and attitude of Indians toward sun exposure and sun protection due to the paucity of research in this arena. Aims and Objectives: This study was aimed at exploring the knowledge and attitudes of Indians toward sun exposure and sun protection measures. Materials and Methods: A cross-sectional survey was conducted using a predesigned questionnaire related to the knowledge, behavior, and attitudes toward sun exposure and sun protection of the participants visiting a dermatology outpatient clinic for various dermatological problems. Results: total of 324 patients were studied. Participants were divided into five age groups of equal number of male and female participants. Mean age was 37.7 ± 13.15. Overall awareness and knowledge was poor and only 14% were using regular sunscreen. Females had better knowledge and attitude toward sun exposure and protection. The most commonly used sun protection measure was avoiding sun during peak hours of the day. Conclusion: The level of knowledge regarding sun exposure hazards was very low among the study population, and sun prevention behaviors were also very poor. Regular use of sunscreen was practiced only by a small fraction of our population. Knowledge of sun exposure and photoprotection was better in urban, young participants, female gender, and also positively associated with higher education and socioeconomic status. Participants from urban background, females, and middle-aged participants had better attitude toward photoprotection.

Are current guidelines for sun protection optimal for health? Exploring the evidence

Exposure of the skin to ultraviolet (UV) radiation is the main risk factor for skin cancer, and a major source of vitamin D, in many regions of the world. Sun protection messages to minimize skin cancer risks but avoid vitamin D deficiency are challenging, partly because levels of UV radiation vary by location, season, time of day, and atmospheric conditions. The UV Index provides information on levels of UV radiation and is a cornerstone of sun protection guidelines. Current guidelines from the World Health Organization are that sun protection is required only when the UV Index is 3 or greater. This advice is pragmatic rather than evidence based. The UV Index is a continuous scale; more comprehensive sun protection is required as the UV Index increases. In addition, a wide range of UVA doses is possible with a UVI of 3, from which there may be health consequences, while full sun protection when the UVI is “moderate” (between 3 and 5) may limit vitamin D production. Finally, the duration of time spent in the sun is an essential component of a public health message, in addition to the intensity of ambient UV radiation as measured by the UV Index. Together these provide the dose of UV radiation that is relevant to both skin cancer genesis and vitamin D production. Further education is required to increase the understanding of the UV Index; messages framed using the UV Index need to incorporate the importance of duration of exposure and increasing sun protection with increasing dose of UV radiation.

A Mobile Technology Intervention With Ultraviolet Radiation Dosimeters and Smartphone Apps for Skin Cancer Prevention in Young Adults: Randomized Controlled Trial

BackgroundSkin cancer is the most prevalent and most preventable cancer in Australia. Despite Australia’s long-running public health campaigns, young Australian adults continue to report high levels of ultraviolet radiation (UVR) exposure and frequent sunburns. Young people are now increasingly turning away from traditional media, such as newspapers and TV, favoring Web-based streaming, which is challenging the health care sector to develop new ways to reach this group with targeted, personalized health promotion messages. Advances in technology have enabled delivery of time- and context-relevant health interventions.ObjectiveThe primary aim of this randomized controlled trial was to test the effect of UVR feedback from a smartphone app or a UVR dosimeter feedback device on sun protection habits, sun exposure behaviors, sunburn, and physical activity levels in young adults.MethodsYoung adults aged 18-35 years (n=124) were recruited from Queensland, Australia, between September 2015 and April 2016, via social or traditional media campaigns and outreach activities in the local community. Participants were randomized into 3 groups for a 4-week intervention: (1) no intervention control group; (2) UVR monitor group, who were asked to wear a UVR dosimeter feedback device set to their skin type; and (3) a SunSmart app group, who were asked to download and use the SunSmart phone app. Data were self-assessed through Web-based surveys at baseline and 1 week and 3 months postintervention.ResultsComplete data were available for 86.2% (107/124) of participants (control group, n=36; UVR monitor group, n=36; and SunSmart app group, n=35). Intervention uptake in the UVR monitor group was high, with 94% (34/36) of participants using the device all or some of the time when outdoors. All SunSmart app group participants downloaded the app on their smartphone. There was no significant difference in the change in the sun protection habits (SPH) index (main outcome measure) across the 3 groups. However, compared with the control group, a significantly greater proportion of the participants in the UVR monitor group reduced their time unprotected and exposed to UVR on weekends during the intervention compared with the baseline (odds ratio [OR]: 2.706, 95% CI 1.047-6.992, P=.04). This significant effect was sustained with greater reductions observed up to 3 months postintervention (OR: 3.130, 95% CI 1.196-8.190, P=.02). There were no significant differences between the groups in weekday sun exposure, sunscreen use, sunburn, suntan, or physical activity.ConclusionsUsing technology such as apps and personal UVR monitoring devices may improve some sun exposure behaviors among young adults, but as the SPH index did not increase in this study, further research is required to achieve consistent uptake of sun protection in young people.Trial RegistrationThe Australian and New Zealand Clinical Trials register ACTRN12615001296527; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=368458 (Archived by WebCite at http://www.webcitation.org/731somROx)

Photoprotection enhanced by red cell wall pigments in three East Antarctic mosses

BackgroundAntarctic bryophytes (mosses and liverworts) are resilient to physiologically extreme environmental conditions including elevated levels of ultraviolet (UV) radiation due to depletion of stratospheric ozone. Many Antarctic bryophytes synthesise UV-B-absorbing compounds (UVAC) that are localised in their cells and cell walls, a location that is rarely investigated for UVAC in plants. This study compares the concentrations and localisation of intracellular and cell wall UVAC in Antarctic Ceratodon purpureus, Bryum pseudotriquetrum and Schistidium antarctici from the Windmill Islands, East Antarctica.ResultsMultiple stresses, including desiccation and naturally high UV and visible light, seemed to enhance the incorporation of total UVAC including red pigments in the cell walls of all three Antarctic species analysed. The red growth form of C. purpureus had significantly higher levels of cell wall bound and lower intracellular UVAC concentrations than its nearby green form. Microscopic and spectroscopic analyses showed that the red colouration in this species was associated with the cell wall and that these red cell walls contained less pectin and phenolic esters than the green form. All three moss species showed a natural increase in cell wall UVAC content during the growing season and a decline in these compounds in new tissue grown under less stressful conditions in the laboratory.ConclusionsUVAC and red pigments are tightly bound to the cell wall and likely have a long-term protective role in Antarctic bryophytes. Although the identity of these red pigments remains unknown, our study demonstrates the importance of investigating cell wall UVAC in plants and contributes to our current understanding of UV-protective strategies employed by particular Antarctic bryophytes. Studies such as these provide clues to how these plants survive in such extreme habitats and are helpful in predicting future survival of the species studied.

Cytotoxic and Membrane Cholesterol Effects of Ultraviolet Irradiation and Zinc Oxide Nanoparticles on Chinese Hamster Ovary Cells

Zinc Oxide (ZnO) nanoparticles are suspected to produce toxic effects toward mammalian cells; however, discrepancies in the extent of this effect have been reported between different cell lines. Simultaneously, high levels of ultraviolet (UV-C) radiation can have carcinogenic effects. The mechanism of this effect is also not well understood. Due to similarities in phenotype morphology after cell exposure to ZnO nanoparticles and UV-C irradiation, we emit the hypothesis that the toxicity of both these factors is related to damage of cellular membranes and affect their sterol content. Wild-type Chinese Hamster Ovary (CHO-K1) cells were exposed to ZnO nanoparticles or UV-C radiation. The amount of absorbed ZnO was determined by UV-visible spectroscopy and the changes in sterol profiles were evaluated by gas chromatography. Cell viability after both treatments was determined by microscopy. Comparing morphology results suggested similarities in toxicology events induced by ZnO nanoparticles and UV exposure. UV-C exposure for 360 min disrupts the sterol metabolic pathway by increasing the concentration of cholesterol by 21.6-fold. This increase in cholesterol production supports the hypothesis that UV irradiation has direct consequences in initiating sterol modifications in the cell membrane.

Functional nanocomposites with graphene-DNA hybrid fillers: Synthesis and surface properties under UV irradiation

In this work, nanocomposites containing assemblies of graphene nanoplatelets (GNP) and double-stranded DNA are investigated as UV-sensitive materials, as they show good electrical properties combined with the chemical sensitivity of DNA to UV radiation, particularly to the more energetic UV-C band. Nanocomposite films were prepared by drop-casting technique after embedding the graphene-DNA fillers in a flexible polydimethylsiloxane (PDMS) matrix using a suitable solvent. The synthesis was optimized in order to improve the dispersion of the graphene-DNA elements in the polymer matrix, as the sensing properties of the nanocomposite materials are highly affected by the amount and homogeneity of the filler dispersion. The electrical and thermal properties of the GNP-DNA/PDMS films, as well as their surface morphology and wettability, were investigated before and after exposure to UV-C radiation using complementary techniques. Results give information on the potential applications of these novel functional nanocomposites for radiation monitoring in environments that are characterized by high levels of biologically-damaging UV radiation.

Effects of ultraviolet radiation and nutrient level on the physiological response and organic matter release of the scleractinian coral Pocillopora damicornis following thermal stress.

Understanding which factors enhance or mitigate the impact of high temperatures on corals is crucial to predict the severity of coral bleaching worldwide. On the one hand, global warming is usually associated with high ultraviolet radiation levels (UVR), and surface water nutrient depletion due to stratification. On the other hand, eutrophication of coastal reefs increases levels of inorganic nutrients and decreases UVR, so that the effect of different combinations of these stressors on corals is unknown. In this study, we assessed the individual and crossed effects of high temperature, UVR and nutrient level on the key performance variables of the reef building coral Pocillopora damicornis. We found that seawater warming was the major stressor, which induced bleaching and impaired coral photosynthesis and calcification in all nutrient and UVR conditions. The strength of this effect however, was nutrient dependent. Corals maintained in nutrient-depleted conditions experienced the highest decrease in net photosynthesis under thermal stress, while nutrient enrichment (3 μM NO3- and 1 μM PO4+) slightly limited the negative impact of temperature through enhanced protein content, photosynthesis and respiration rates. UVR exposure had only an effect on total nitrogen release rates, which significantly decreased under normal growth conditions and tended to decrease also under thermal stress. This result suggests that increased level of UVR will lead to significant changes in the nutrient biogeochemistry of surface reef waters. Overall, our results show that environmental factors have different and interactive effects on each of the coral’s physiological parameters, requiring multifactorial approaches to predict the future of coral reefs.

SunSmart news? Traditional media coverage of sun protection issues during springtime in New Zealand.

Cutaneous melanomas and keratinocyte carcinomas (nonmelanoma skin cancer) are highly prevalent in New Zealand (NZ), making skin cancer a priority area for cancer control. Spring is an important time for encouraging sun-safety, due to ultraviolet radiation (UVR) levels becoming hazardous. The news media have a potential to play an important role in reminding people and emphasising the importance of sun-safety. This study aimed to describe how the traditional NZ media portrayed sun-safety and skin cancer in spring news stories. A media monitoring company collated stories related to cancer during spring 2016. These were reviewed for inclusion and content was coded according to the cancer type described. Stories focused on skin cancer and sun protection issues were coded according to the position on the cancer control continuum. Skin cancer and sun-safety represented 3.6% (n=110) of all cancer stories published. Stories mainly related to primary prevention (72%), early detection (37%) and survivorship (27%). The main risk factors identified included sun exposure (49%) and tanning (25%). Traditional media coverage of skin cancer remains relatively low during springtime. It is heartening to see that most stories included prevention information. SO WHAT?: Given the impact of skin cancer in NZ, and the importance of springtime as a period for behaviour change to reduce risk, there is considerable scope for increased media coverage and advocacy. Further research could usefully analyse media trends throughout the year and within specific media platforms, both traditional and new, in order to further disseminate information to the NZ public.

Physiological Characteristics and Related Biochemical Parameters of Snow Algae from King George Island, Antarctica

Red and green snow caused by snow algal blooms is common on glaciers and snowfields worldwide. Reddish and greenish snow samples containing algae were collected at the vicinity of penguin rockeries on King George Island (62°13′S, 58°47′W, near the King Sejong Station), Antarctica in February 2017 to investigate their physiology. Eight pigments and six fatty acids were detected from the samples. No difference in pigment and fatty acid (FA) composition was found between reddish and greenish snow samples. In contrast, spectral profiling and mycosporine-like amino acids (MAAs) were different between reddish and greenish snow. Particularly in greenish snow, a high absorbance between 450–600 nm was observed. The average MAA concentration was 316.0 μg g-1 in greenish snow, which was higher than that of reddish snow (278.2 μg g-1). The MAA to Particulate organic carbon (POC) ratio (mg (g C)-1) for reddish snow (6.2 mg (g C)-1) was higher than that of greenish snow (2.6 mg (g C)-1). These results suggest that reddish and greenish snow are considered to be the same species based on pigment and FA composition. Compared with photoprotective pigments, MAAs offer snow algae a more effective photoprotection strategy to promote tolerance of natural levels of ultraviolet radiation (UVR).

Forming perchlorates on Mars through plasma chemistry during dust events

We report experimental evidences to support a new formation mechanism, multiphase redox plasma chemistry, for perchlorate on Mars observed during the Phoenix mission, whose high concentrations and high ClO4/Cl ratio cannot be fully interpreted by photochemistry. This chemical reaction occurs between Cl-bearing minerals on the Mars surface and free radicals generated by electrostatic discharge (ESD) during Mars dust events (dust storms, dust devils, and grain saltation).We conducted simulated ESD experiments in a Mars chamber with pure CO2, CO2 + H2O(g), and Mars Simulate Gas Mixture at Martian atmospheric pressure. We directly observed (1) the instantaneous generation of atmospheric free radicals CO+2, CO+, OI, HIII, HII, OH, ArI, N2, and N+2 in normal glow discharge (NGD), detected by in situ plasma emission spectroscopy, and O3 by UV and Mid-IR spectroscopy; (2) the fast transformation of NaCl to NaClO3 and NaClO4 detected by laser Raman spectroscopy, with oxychlorine enrichment at the sample surfaces confirmed by ion chromatography. Through two sets of experimental comparison, we found that the oxidation power of ESD-electron is three orders of magnitude higher than that of UVC-photon. We scaled our experimental results to the modeled ESD in Mars dust events and Mars surface UV radiation level, and concluded that plasma chemistry occurred during Mars dust events can be an additional important formation mechanism for the large amounts of perchlorates observed during various missions to Mars.

Solar Ultraviolet Radiation Exposure and Sun Protection Behaviors and Knowledge Among a High-Risk and Overlooked Group of Outdoor Workers in South Africa.

The exposure of outdoor car guards to solar ultraviolet radiation (UVR), the majority with deeply pigmented skin, to solar UVR was measured for five consecutive days during early spring (September 2017) in South Africa using electronic UVR dosimeters attached to the upper arm of each participant. The exposure of the nape of the neck, forehead, nose, cheek and hand was extrapolated from the measurements. The onsite ambient solar UVR on a flat, horizontal, unshaded surface was measured concurrently. The sun-related knowledge, behavior and attitudes of the car guards were evaluated using questionnaires. Total personal daily solar UVR exposure as a percentage of the ambient solar UVR exposure was 24%. The exposure of car guards on several body sites was in excess of the occupational threshold limit value. Sleeved shirts and hats were the most commonly used sun protection measures (worn by 70% and 80%, respectively). Considering the high levels of solar UVR reported on most days throughout the year in South Africa, more studies quantifying the personal exposure of outdoor workers in both the informal and formal sectors are necessary.

New Approaches to Skin Cancer Prevention: Can Encouraging Skin Checking Increase Engagement in Sun Protection Behaviours?

Background: Skin cancer is one of the most common types of cancer in the world and incidence rates are increasing globally. Efforts to encourage individuals to engage in sun protection behaviors that minimize their risk of skin cancer are therefore urgently needed. In Australia, the context of the current study, UV radiation levels are particularly intense and public health campaigns have been successful in encouraging behaviors such as using sunscreen and wearing a hat. However, recent years have seen a plateau in engagement in such behaviors and new approaches are required to facilitate further gains. Encouraging people to check their skin for signs of skin cancer may be one such approach as it has the potential to increase the salience of skin cancer and the need to protect oneself from UV radiation. Aim: To assess the relationship between skin checking and sun protection behaviors to inform skin cancer prevention campaigns. Methods: Computer-assisted telephone interviewing was used to survey nearly 700 adults. Frequency of engagement in various sun protection behaviors (wearing a hat, wearing protective clothing, using sunscreen) was assessed. Respondents were also asked whether they had checked their skin for skin cancer and how confident they were in their ability to spot the signs of skin cancer. Results: Path analysis revealed greater confidence in one's ability to detect the signs of skin cancer to be associated with skin checking. In turn, skin checking was found to be associated with more frequent engagement in all of the assessed sun protection behaviors. Conclusions: Public health campaigns that increase people's confidence in their ability to detect the signs of skin cancer have the potential to encourage skin cancer reduction behaviors in the form of both skin checking and sun protection and perhaps shift the plateau in engagement of sun protection behaviors observed in recent years.

Persistence of V. cholerae O139 Biofilm Against Physical, Chemical and Antibiotic Lethal Challenges

Since its emergence, cholera caused by the bacterium Vibrio cholerae remains as a significant threat to human health. The continued persistence of this pathogen against many unfavourable conditions made challenging to eradicate cholera, especially in the developing countries. In the hostile conditions, the bacterium is known to form a self-enclosed polymeric structure called ‘biofilm’ which serves as a major factor responsible for its persistence and transmission. Hence, the authors aimed to understand the effectiveness of relevant physical, chemical and antibiotic treatments against the biofilm of this bacterium. For the study, the biofilm of V. cholerae O139 wild type and its isogenic Tn5-mutants that differ in their biofilm phenotype (biofilm proficient and biofilm deficient) were exposed to different levels of pH, salinity, temperature, UV radiation, H2O2, chlorination, and antibiotics. It was observed that biofilm culture of both wild type and the biofilm-proficient mutant exhibited detectable survival rate up to pH 2.0, salinity 3.5 M, temperature 50 °C, H2O2 80 mM, NaOCl 12.5 mg/L and at several folds increased antibiotic concentration (Ciprofloxacin 2 mg/L, and Doxycycline 256 mg/L) as compared to the biofilm defective mutant and the planktonic cultures of respective strains. As the biofilm of the cholera pathogen or the cholera biofilm resists several lethal challenges, it is essential to target the biofilm and its residents for the complete destruction of the infection source and thereby to prevent transmission of cholera.

Investigating Multiple Chemical and Contextual Exposures in the Nurses' Health Studies

The Nurses&amp;#8217; Health Study and Nurses&amp;#8217; Health Study II are U.S.-based prospective cohort studies with decades of follow-up obtained using mailed questionnaires administered every two years. The resultant updated residential address history provides an opportunity to assess health effects of multiple environmental and contextual risk factors in adulthood. We have added numerous residence-level spatiotemporal data on chemical and contextual exposures to the detailed individual-level personal exposures collected on the questionnaires. To date, we have taken advantage of publically available data, purchased data processed by third parties, and developed sophisticated spatiotemporal models at various scales to assess levels of air pollution, temperature, ultraviolet radiation, greenness, walkability, population density, and socioeconomic factors. We also have assessed spatial variation in light at night (LAN), noise, dioxin emissions, and radon. Our breadth of environmental and contextual variables is continually expanding as new data sources come to our attention at higher spatial and temporal resolutions or as new exposures emerge. This georeferenced resource has opened up new opportunities to study environmental etiology of a host of chronic diseases, information on which is obtained originally by self-report during routine follow-up, supplemented by targeted questions and medical record review as appropriate. In this presentation, we discuss the opportunities and challenges of linking environmental and contextual variables to an existing epidemiologic cohort, potential measurement error concerns, as well as approaches to consider these exposures simultaneously with each other and other lifestyle and social variables.