document: Previous studies have shown that there are two main mechanisms for the development of radiation-induced DSBs [16,17]. For γ-ray radiation, single step is the main process to cause DSBs (see Figure 3b), which is attributed to the generation of number of ROS upon the incident of individual photon of γ-ray. Whereas photo-radiation causes DSBs through two step mechanism (Figure 3a) by reflecting that each single photon causes mostly single ROS and thus induces only single strand break. Then, when a second single strand break occurs where near the existing single strand break, DBS is caused, i.e., the two step mechanism. Summarizing the results and discussion we may conclude as that: (1) The significant protective effect of AA against photo-induced damage may reflect the effective diminish of ROS by AA. (2) For the γ-ray induced DSB, the protective effect by AA is a little bit weaker than the case of photo irradiation. This may be due to the generation of numbers of ROS by single photon of γ-ray. Surviving oxygen species against the diminishment effect by AA may cause DSBs. (3) As for the DSBs by ultrasound, damage is caused by the shockwave through the generation of cavitations [18]. Thus, the chemical effect of AA to diminish ROS is considered to be negligibly small for the protection of DSBs.
doc_bio_tags: O O O O O O O O O O O O O O O B O O O O B I O O O O O O B O O O O O O O O B I I I I O O O O O B O O O O O B O B I I O O O O O O O B O O O B O O O O B I I O O O O B I I O O O O O B I I B O O O O B I I O O O O O O O O O O O O O O O O B O O O O O O O O O B O B O O O O O O O O O O B O O O O O O O O O B O O O O O O O O O O O B O O B O O O O O O O O O O B O O B O O O O B O B O O O O O B O O O O B O O O O O O B O B I O O O O O O O O O O B
extractive_keyphrases: aa cavitations dbs diminish ros dsbs generation of number of ros photo photon ros shockwave single step single strand break two step mechanism ultrasound
abstractive_keyphrases: development of radiation-induced dsbs photo-induced damage photo irradiation photon of γ-ray photo-radiation radiation-induced dsbs single photon of γ-ray strand γ-ray induced dsb γ-ray radiation