In-vivo and in vitro assessments of the radioprotective potential natural and chemical compounds: a review.

PURPOSE: The study of the radioactive role of natural and chemical substances on human and animal studies has been the subject of research by some researchers. Therefore, the review of some of the past and current studies conducted in this field, can provide helpful information to elucidate of the importance of radioprotective components in reducing radiation exposure side effects. METHODS: The authors search for keywords including In vitro, In vivo, Radioprotective, Ionizing radiation, and Vitamin in ScienceDirect, Scopus, Pubmed, and Google Scholar databases to access previously published articles and search for more reference articles on the role of radioprotective materials from natural and chemical compounds. RESULTS: Radiation exposure can produce reactive oxygen species (ROS) in the body, however most of which are eliminated by the body's natural mechanisms, but when the body's antioxidant systems do not have enough ability to neutralize free radicals, oxidative stress occurs, which causes damage to DNA and body tissues. Therefore, it is necessary use of alternative substances that reduce and inhibit free radicals. CONCLUSION: In general, recommended that antioxidant component(s) can be protect tissue damages in humans or animals, due to the their ability to scavenge free radicals generated by ionizing radiation.

The Effect of Low Frequency Noises Exposure on the Precision of Human at the Mathematical Tasks.

Background: Low-frequency noise is produced from different sources in the working environments such as pumps. Thus, the aim of this study was to investigate the effect of low-frequency noise on precision and focusing of the studied subjects. Methods: This cross-sectional-interventional study was performed on 13 students of Isfahan University of Medical Sciences. The precision of individual subjects was evaluated using the mental arithmetic test. The sound sources with frequencies of 125, 250, and 1000 Hz at 75, 85, and 95 dB sound pressure levels. Also, the rate of precision was measured before the exposure (time "zero"), and at 45 and 90 min. SPSS (Ver. 26) software was used to analyze the data. Results: Comparison of the precision scores of the individuals between the frequencies of 125 and 250 Hz at the sound pressure level of 75 dB and at 45 min (P = 0.032). And 90 min (P = 0.006). And also, the frequencies of 250 Hz and 1000 Hz at the time of 45 min. At the sound pressure levels of 85 dB (P = 0.019). And 95 dB (P = 0.043) and at the time of 90 min. At the sound pressure levels of 85 dB (0.027). And 95 dB (P = 0.009) demonstrated a significant difference. Conclusions: We concluded that low frequency noises could reduce the person's precision. While for 125 Hz noises, just increasing of the exposure time was effective on the precision reduction. But for 250 Hz noises, both parameters increasing including exposure time and sound pressure levels, was effective.