Introduction
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Biological modeling descibes the response of cells to the initial damage. Overall, the goal is to develop a comprehensive and inclusive modeling from the initial physics events to the final observed biological outcome. In many cases, the development of biological models and track structure Monte Carlo simulations is performed by different groups.  TOPAS-nBio supports the Standard for DNA Damage (SDD) [Schuemann2019]_, which offers a connection between the simulation of DNA damage induction in the physical and chemical stage, and the modeling of DNA repair kinetics. The strengh of the SDD is that it allows cross-comparison of the results of damage induction codes, cross-comparison of predicted outcome from biological models using the same DNA damage distribution, and a link between the two modeling realms.