Molecular Biology

In principle, we either look for a direct hit on the DNA, in which the coordinates, size of the energy deposition and type of interaction are recorded, or the reaction of radical species, diffusing in the environment around the DNA.The mean diffusion distance of radicals in the environment of the DNA is primarily governed by the scavenging capacity of the buy Nortriptyline hydrochloride medium based on the rate constants for the reactions with DNA and with many other reactive molecular species.If there is a reaction between the target DNA and the radicals generated, the position, time and type of reaction are recorded.After scoring the energy deposition events and reactions of radicals, one then searches for possible damage in each DNA segment according to a set of assumptions based on experimental and theoretical information on the mechanisms and pathways to DNA damage.For scoring the long tracks of high energy electrons, alternative methods need to be employed for sam pling of the tracks. However, the resolution of the experimental techniques is still insufficient for detailed analysis of the hit region of DNA.In calculations of the yields of strand breaks, difficulties with the computational methods remain with the modelling of large macromolecules, tracing the target to find sites of interactions and the primary data on the pathways to strand breakage.Using the assumptions for the simulations discussed below, a main feature of existing models is that the calculated yields of strand breaks are in reasonable agreement with experimental data.The classification of damage according to complexity, two ssb or more on the same strand. Similarly, dsb can also be considered as simple, complex with one double strand and one or more additional strand breaks on one strand only, and the most complex class involving at least two dsb in the region of the hit of the DNA. Model provides classification of additional damage according to the number of base damages in each of the classifications of strand breakage by complexity.Base damages were divided into groups of, and damaged bases in the DNA segment.The overall estimation of base damage has been presented as the ratio of the number of base damages to strand breaks assigned as SPD.Contributions of hydrogen atoms and hydrated electrons to DNA strand breakage were ignored as these were considered not to cause appreciable strand breaks.The first of the required parameters listed above is the absolute frequency distribution of energy depositions per unit dose in the volume of the target such as DNA.The database for the frequencies of energy deposition in a small volume corresponding to the biological targets for electrons, xphotons and ions, and the methods of the calcula tion can be found in various publications. The frequencies of energy deposition can also be generated using an algorithmic method. The second of the parameters in elucidation of DNA damage is the size of energy deposition in DNA to cause a strand break.Analysis of experimental data shows a lin ear dose relationship for the dsb yield.This also implies that dsb are produced predominantly by single track events.

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