Introduction: Free radicals are natural metabolic products that can cause some serious damages to living cells like molecular oxidation and genetic mutation. Antioxidants are natural or synthetic molecules which inhibit the living cell‘ s oxidation caused by free radicals. One of the natural antioxidants is riboflavin, which is available in many plants and animal materials. Riboflavin molecule is a photosensitive material which through the photochemical reaction causes chemical changes in the adjacent molecules. The effect of antioxidant and photosensitizer properties. Materials and Methods: In this study, the effect of four important parameters including temperature, riboflavin concentration, time and light irradiation on the antioxidant properties of riboflavin were investigated. The antioxidant activity of the riboflavin was determined based on the scavenging DPPH free radical (2, 2-diphnyl-1-picrylhydrazyl) using UV-Vis spectrophotometer. Results: The antioxidant activity of riboflavin is increased by increasing the concentration in the range of 0. 4-0. 7 mM. In the presence of Sunlight, the free radicals of DPPH were completely scavenged by the antioxidant activity of riboflavin. In the applied temperature range, by increasing the temperature, the antioxidants activity became more intense in the free radical scavenging. Regarding kinetic, the DPPH free radical scavenging reaction was described using the first-order kinetic equation. Conclusion: According to this study, riboflavin as a photosensitive materials has a significant antioxidant effect on free radical DPPH in the presence of Sunlight.

Persistence of benthiocarb in soil as affected by UV and Sunlight exposure was studied. Treated soil was placed in petri plate, brought to field capacity moisture and then exposed to UV and Sunlight. Residues of benthiocarb in soil dissipated with half lives of 2.10, 11.85 and 43.63 days under UV, Sunlight and dark condition, respectively. Soil samples kept under dark showed the slowest dissipation. Further, benthiocarb residues dissipated quickly under UV light as compared to Sunlight. Exposure of thin film of benthiocarb confirmed that it is photo labile and dissipated very fast with half life of 1.16 and 1.77 days following exposure to UV and Sunlight, respectively. The study revealed that UV component of Sunlight is an important factor for benthiocarb dissipation.

To investigate the ocular surface status in individuals having long-term occupational Sunlight exposure. This study was carried out with a historical cohort design. Long-term occupational Sunlight exposure was considered the main exposure. The exposure group included individuals who had direct Sunlight exposure in their workplace (124 people with a mean age range of 31. 6±, 6. 32), and the non-exposure group was comprised of 182 people (mean age range of 31. 6±, 6. 32) who worked indoors and had no longterm exposure to Sunlight during work hours. The mean of TBUT in the Sun-exposure group (10. 91±, 6. 64 sec. ) was significantly lower than the non-exposure one (13. 91±, 9. 67 sec. ) (P=0. 001). 42. 9 percent of the members of the non-exposure and 58. 9 of the sun-exposure group demonstrated TBUT values lower than 10 seconds. While the mean of OSDI in the exposure group was higher than in the non-exposure group, this difference was not statistically significant. Based on the OSDI results, 51. 6 percent of the non-exposure group and 58. 9 percent of the exposure group suffered from dry eye. The prevalence of diseases such as Pterygium, blepharitis, and pinguecula in the sun-exposure group was significantly higher than in the non-exposure group (P<0. 0001). Based on the results of this study, people who have long-term occupational Sunlight exposure tend to have more unstable tear films compared with people who do not have such exposure. In addition, the prevalence of diseases such as Pterygium, blepharitis, and pinguecula is higher among these people.