Given the prevalence and risk associated with indoor tanning among college students, university campuses constitute a prime target for skin cancer prevention. This report identifies the successes and challenges faced in promoting a campus-wide tan-free policy through the National Council on Skin Cancer Prevention (NCSCP) Indoor Tan-Free Skin Smart Campus Initiative. Beginning in February 2016, we communicated with university faculty or staff members who have participated in skin cancer prevention via education, clinical care, or research at 20 universities regarding the steps to adopt the tan-free policy. One campus, East Tennessee State University (ETSU), successfully fulfilled all criteria and implemented the policy change to become the first US Indoor Tan-Free Skin Smart Campus. The greatest challenge faced in recruiting campuses was gaining administrative support. Reported reasons for not adopting the policy change included wanting to wait for other schools to join first and not seeing it as a top priority. Despite the importance of improving skin cancer awareness and decreasing tanning among university students, we faced several challenges in promoting campus-wide policy change. We identify a need for research on effective ways to disseminate university health policies and increased involvement of healthcare providers in policy-related work.

Leaf epidermal transmittance of ultraviolet radiation (280-400 nm) was examined in several plant species to determine the capability of the epidermis to attenuate solar ultraviolet radiation. Epidermal samples were mechanically isolated and examined with a spectroradiometer/integrating sphere for transmittance. A survey of 25 species exposed to natural insolation was conducted. Although the species differed in life form, habitat type, and epidermal characteristics, epidermal transmittance was generally less than 10%. Ultraviolet radiation was attenuated 95 to 99% in more than half of the species. In 16 species, flavonoid and related pigments in the epidermis accounted for 20 to 57% of the attenuation. Several species exposed to supplemental ultraviolet irradiation (288-315 run) in a greenhouse exhibited significant (p≤0.05) depressions in epidermal transmittance of 31 to 47%, apparently resulting from an increase in ultraviolet-absorbing pigments.

This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu).

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The effects of low doses of ionizing radiation on living things is a continually evolving area of research. Importantly, low dose effects were historically overlooked and not properly accounted for the assessment of risk to human health, as is the case with the contentious linear no-threshold model. These low dose effects are now known to be relevant to human health in both accidental and intentional exposures, including doses relevant to medical diagnostics and therapeutics. Furthermore, there is a relative dearth of information on low dose effects in non-human species, which necessitates further investigation and evaluation of radiosensitivity. Radiation-induced bystander effects occur in organisms due to the receipt of signals from directly irradiated cells, which act to communicate radiation damage to surrounding cells. Recent research has identified one type of bystander signal which is carried by photons of biological origin, however the effects produced in bystander cells receiving these photons has not been extensively investigated. It was suspected, based on previous research, that reactive oxygen species participate in the manifestation of this bystander effect. Three mammalian cell lines were assessed for their ability to produce bystander photons upon direct irradiation; subsequently, radiologically unexposed cells were exposed to the resulting photons and assayed for biological effects. The human cell lines used exhibited significant photon emissions and oxidative stress, clonogenic cell death, reduced cellular metabolism, and compromised mitochondrial oxidative phosphorylation following exposure to these photons. The use of a melanocyte cell line indicated that these effects are attenuated by melanin, and this is suspected to occur through photoabsorption or antioxidant mechanisms. Additionally, the same assays were conducted following cell exposure to hydrogen peroxide at low concentrations to assess responses to oxidative stress relevant to bystander responses, indicating less overall sensitivity in the examined melanocytes. These findings are significant because they contribute to our understanding of the mechanisms behind low dose biological effects, because they further challenge the linear no-threshold model and other models based on target theory, because they provide evidence for differential responses to the physical bystander signal in non-human species, and because secondary photon emissions are likely relevant to the medical radiation sciences. / Thesis / Master of Science (MSc) / Low doses of ionizing radiation interact with living things differently than high doses. Low dose effects are now known to be relevant to human health and protection of the environment. Radiation-induced bystander effects occur in cells due to the receipt of signals from irradiated cells which act to communicate radiation damage to surrounding cells. One type of bystander signal is carried by photons emitted from directly irradiated cells, however the effects produced in bystander cells receiving these photons has not been extensively investigated. This thesis investigates the cellular effects of these “biophotons”, including cell survival, oxidative stress, and metabolism.

The amount of solar ultraviolet radiation (UVR, 290-400 nm) reaching Earth’s surface is increasing due to ozone depletion and global climate change. Embryos of the purple sea urchin, Strongylocentrotus purpuratus, provide an ideal system for examining how UVR affects developing marine organisms and cells in general. To model the protein-mediated cell cycle response to UV-irradiation, six batches of S. purpuratus embryos were exposed to UVR, monitored for delays in the first mitotic division and examined for global proteomic changes. Embryos from each batch were exposed to or protected from artificial UVR for 25 or 60 min. Embryos treated with UVR for 60 min cleaved an average of 23.24 min (±1.92 s.e.m) later than the UV-protected embryos. Protein expression of UV-protected and UV-treated embryos was examined at 30 and 90 min post-fertilization using two dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (2D SDS-PAGE) and mass spectrometry (MS). Proteins were isoelectrically focused (pH 4-7) and separated by molecular weight using SDS-PAGE. At least 1,306 protein spots were detected in all gels. A total of 171 protein spots (13% of the detected proteome) migrated differently in UV-treated embryos at 30 min post-fertilization and 187 spots (14%) at 90 min post-fertilization (2-way ANOVA, P= 0.03, n=6). Our results identify the differential migration of proteins from multiple cellular pathways and are the first to indicate that the mechanisms involved in the protein mediated UV-induced developmental delay are integrated among pathways for cellular stress, protein turnover and translation, signal transduction, general metabolism and involve the cytoskeleton.

<p dir="ltr">Prevention of the spread of diseases caused by airborne biological pathogens is of great concern. This was highlighted by the Covid-19 Pandemic, which was caused by the SARS-CoV-2 virus. One method for preventing the transmission of airborne pathogens is UV-C irradiation, which has been proven to effectively inactivate a wide range of airborne pathogens, including influenza viruses and coronaviruses. Disinfection of air using UV-C is usually employed through upper-room Ultraviolet Germicidal Irradiation (UVGI), UV-C based air cleaners in HVAC ducts, or stationary cabinets. In the research presented herein, near-field applications of UV-C disinfection are explored through implementation in personal protective equipment.</p><p dir="ltr">A series of personal protective devices were developed for real-time inactivation of airborne pathogens in military or civilian applications. The devices use UV-C radiation from low-pressure mercury lamps (254 nm) and UV-C LEDs (nominally 277 or 282 nm) to inactivate airborne pathogens that are inhaled or exhaled by users, thereby reducing the risk of disease transmission. The devices employ Porex PMR20, a material highly reflective of UV-C radiation, to promote photon recycling and improve the fluence rate fields inside the reactors. To quantify the efficacy of these UV-C devices, testing procedures were developed and applied. A two-part procedure was employed: (1) measurement of the fluence rate using the Micro Fluorescent Silica Device (MFSD) together with a positioning device and (2) biological experiments using T1 bacteriophage as an aerosolized challenge agent to quantify virus inactivation.</p><p dir="ltr">The fluence rate measurements were completed by fixing the location of the MFSD probe and moving the reactors to precise locations using the positioning device. The MFSD measurements were converted to fluence rate using measurements from an NIST-calibrated radiometer and collimated UV-C sources. When comparing the measurements with and without the PMR20, the local fluence rate for the LED reactors was found to be amplified by up to 10 times the value without the PMR20. A central peak was also found for both LED reactors, which was not present in measurements without the PMR20. Of the two LED reactors, the Nichia Reactor was found to have higher peaks in fluence rate, probably due to the higher output from the LEDs when compared to the JLED LEDs. The LP Hg Pod was found to have less significant amplification from the PMR20, with the maximum amplification being only 3 times the value without PMR20. The fluence rate near the walls lined with PMR20 was found to have the highest amplification for the Pod reactor, due to the lamp being located at the center of the reactor (unlike the LED reactors, where UV-C sources were positioned along the reactor walls).</p><p dir="ltr">The biological experiments were conducted using aerosolized T1 bacteriophage as a challenge agent. T1 was selected for these experiments because it has been shown to be more resistant to inactivation at the wavelengths of interest than most airborne pathogens; as such, T1 is a conservative surrogate for airborne pathogens in these applications. Experiments were conducted first at one flow rate and subsequently at a range of flow rates to quantify the effectiveness of the reactors and the impact the PMR20 on the inactivation response. When tested at the lowest flow rate of 2.5 L/min, all three reactors were found to provide inactivation at least as effective as the nominal removal provided by an N95 mask (95% or 1.3 log₁₀ units). The LP Hg Pod reactor was found to provide at least this level of inactivation (1.3 log₁₀ units) at flow rates up to 52.5 L/min when PMR20 lined the reactor. When tested without the PMR20, the loss in inactivation was substantial at 52.5 L/min but not at the lower flow rates.</p><p dir="ltr">The testing protocol developed and applied in this project could be applied to a range of other reactors intended for disinfection of air. A need exists to standardize testing and validation methods for UV-C based reactors and devices that are used to disinfect air. As such, the methods described herein may allow translation to other UV-C based devices.</p>

Understanding the natural processes that have taphonomic effects on bone is an important part of accurately determining the postmortem interval (PMI). Ultraviolet radiation is one of these various natural processes that weather bone. The present study quantifies the degree to which differential exposure to sunlight affects bone bleaching and weathering. In this study, 140 Sus scrofa long bones were placed in two different microenvironments (grassland and woodland) within a New England setting. Upon the completion of a one-year observation period, 100% of the bones had reached bleaching level 4, and 9.85% (n = 13) of the bones had reached weathering stage 1, with the majority (n = 11) being from the woodland sample. The results indicated that the microhabitat that each sub-sample was deposited within played a statistically significant role in the degree and rate of bleaching and weathering on the bone, with chi-square tests all indicating a p value of < 0.001. In addition, results indicated that environmental variables that led to the more rapid decomposition of soft tissue, such as temperature, humidity, and the type of plant coverage, may play a greater role in the level of bleaching and weathering achieved by the bones, rather than simply the degree of exposure to UV radiation and light intensity.

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