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They are non-thermal in origin, and the emission of biophotons is technically a type of bioluminescence, though the term "bioluminescence" is generally reserved for higher luminance systems (typically with emitted light visible to the naked eye, using biochemical means such as luciferin/luciferase).
Free radical toxicity induced by xenobiotics and the subsequent detoxification by cellular enzymes (termination). Effects of ROS on cell metabolism are well documented in a variety of species. [ 19 ] These include not only roles in apoptosis (programmed cell death) but also positive effects such as the induction of host defence [ 36 ] [ 37 ...
Radiation used for cancer treatment is called ionizing radiation because it forms ions in the cells of the tissues it passes through as it dislodges electrons from atoms. This can kill cells or change genes so the cells cannot grow. Other forms of radiation such as radio waves, microwaves, and light waves are called non-ionizing.
The hydroxyl radical, Lewis structure shown, contains one unpaired electron. Lewis dot structure of a Hydroxide ion compared to a hydroxyl radical. In chemistry, a radical, also known as a free radical, is an atom, molecule, or ion that has at least one unpaired valence electron.
The hydroxyl radical can damage virtually all types of macromolecules: carbohydrates, nucleic acids , lipids (lipid peroxidation) and amino acids (e.g. conversion of Phe to m-Tyrosine and o-Tyrosine). The hydroxyl radical has a very short in vivo half-life of approximately 10 −9 seconds and a high reactivity. [5]
The body's range of defense against all of these active oxidizing agents is hardly surprising, then, given their "deliberate" employment as antimicrobial agents in the immune response. [14] Reactive oxygen species also play an important role in the hypersensitive response of plants against pathogen attack.
Photodissociation, photolysis, photodecomposition, or photofragmentation is a chemical reaction in which molecules of a chemical compound are broken down by absorption of light or photons. It is defined as the interaction of one or more photons with one target molecule that dissociates into two fragments.
However, very high energy particles can produce visible effects on both organic and inorganic matter (e.g. water lighting in Cherenkov radiation) or humans (e.g. acute radiation syndrome). [ 4 ] Ionizing radiation is used in a wide variety of fields such as medicine , nuclear power , research, and industrial manufacturing, but is a health ...