Introduction
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TOPAS-nBio facilitates the use of the physical and chemical processes available in the `Geant4-DNA Toolkit`_.

TOPAS-nBio further provides additional capabilities:
 
 1. New physics and chemistry lists designed to match experimental G-values as described in our publications :ref:`Citations`
 2. The possibility to customize physical models using modules involved in the pre-defined physics list.
 3. Definition of regions to activate different physics lists, e.g. Geant4-DNA.
 4. The use of a variance reduction techniques.
 5. Reconfiguration of parameters for the physico-chemical stages.
 6. Explicit transport and visualization of the chemical species in the chemical stage.

Here we provide a list of available options for the physics and chemistry settings as well as several examples to retrieve the spatio-temporal information of the physical and chemical tracks in different geometrical components, e.g. via particle tuple or single and double strand breaks. 

.. _Geant4-DNA Toolkit: http://geant4-dna.org