196,218 research outputs found
Mechanistic and phenomenological models for the estimate of radiation-induced biological damage. Physica Medica 17, 3-12.
No full textDifferent techniques for modelling the radiation action on biological targets are analysed, focussing the attention on phenomenological and mechanistic approaches. Phenomenological models allow practical applications (typically in radioprotection and radiotherapy) and are characterised by descriptive features aimed to organise the experimental observations within a formal structure. Mechanistic models are used in basic research and are aimed to reach a better understanding of the physical, chemical and biological processes that, from the initial energy depositions, lead to biological damage. Many different orders of magnitude are involved, both at a spatial level (from atomic dimensions to cellular and organ dimensions) and at a temporal level (from the 10(-15) s of the physical interactions to the hours, and possibly years, of the biological processes). The following aspects are treated: track structure; DNA damage; chromosome aberrations; cell inactivation; low doses and mixed fields. The attention focuses on the comparison between simulations and experiments, the comparison between mechanistic and phenomenological approaches, the determination of the model parameters (in particular on the uncertainties and correlations) and the role of the models in radioprotection and radiotherapy applications
Nuclear architecture and radiation-induced chromosome aberrations: models and simulations.
No full textKnowledge of radiation track structure and its interaction with biological targets is a fundamental starting point
in understanding the mechanisms underlying the induction of biological damage. In this context Monte Carlo codes are a
powerful tool of investigation, allowing one to simulate both track structure and the features of the target(s) of interest at
different scales, from nanometres (linear dimensions of DNA) to micrometres (linear dimensions of human cell nuclei and
interphase chromosome territories). In the light of recent experimental findings on nuclear architecture, different approaches
in modelling chromosome structure and aberration induction are discussed. In particular, a model is presented in which
chromosome territories were explicitly described as subnuclear regions and aberration induction was modelled by coupling
the structure of the target with that of the radiation track. Comparisons between model predictions and experimental results
from the literature are also reported
Caratterizzazione genetica di popolazioni italiane di scazzone. (Cottus gobio L., 1758).
No full textFrom track structure to biological endpoins: models, codes and MC simulations to investigate radiation action and damage formation.
No full textThe investigation of the action of ionising radiation on biological structures requires a detailed analysis of the various stages underlying damage induction
and evolution. In order to take into account the stochastic aspects characterising the process of interest, "ab initio" models and MC simulation codes are
required, which start from the physical track structure and follow its time evolution, taking into account the various levels of organisation of the biological
targets (DNA, chromosomes etc.). Representative examples of the activities in this area of the Universities of Milan and Pavia will be presented, focusing on the development of models aimed: a) to better understand the action mechanisms of ionising radiation, in the framework of the EC project "Low Dose Risk Models" coordinated by the GSF Institute of Munich; b) to study the induction of chromosome aberrations and their possible use as biomarkers, mainly in the framework of the INFN experiment "DOSBI", developed in collaboration with the University of Naples; c) to provide basic data for applicative tools
developed for hadron therapy and space radiation protection, in the framework of the INFN projects "ATER.FIBI" and "FLUKA" and the ASI (Italian Space Agency) project "Influence of the shielding in the space radiation biological effectiveness"
Organizzazione dei cromosomi in interfase e aberrazioni cromosomiche: modelli e simulazioni Monte Carlo
No full textModelling chromosomal aberration induction by ionising radiation: mechanistic approaches based on track structure simulations
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Modelli e simulazioni dell'interazione tra radiazioni ionizzanti e strutture biologiche.
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