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Articles de revues sur le sujet « MONTE-CARLO TRACK STRUCTURE »

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Auteur : Grafiati
Publié le 11 mars 2023

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1

Toburen, Larry H. « Challenges in Monte Carlo track structure modelling ». International Journal of Radiation Biology 88, no 1-2 (19 mai 2011) : 2–9. http://dx.doi.org/10.3109/09553002.2011.574781.

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Douglass, Michael, Scott Penfold et Eva Bezak. « Preliminary Investigation of Microdosimetric Track Structure Physics Models in Geant4-DNA and RITRACKS ». Computational and Mathematical Methods in Medicine 2015 (2015) : 1–8. http://dx.doi.org/10.1155/2015/968429.

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The major differences between the physics models in Geant4-DNA and RITRACKS Monte Carlo packages are investigated. Proton and electron ionisation interactions and electron excitation interactions in water are investigated in the current work. While these packages use similar semiempirical physics models for inelastic cross-sections, the implementation of these models is demonstrated to be significantly different. This is demonstrated in a simple Monte Carlo simulation designed to identify differences in interaction cross-sections.
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Endo, S., E. Yoshida, H. Nikjoo, S. Uehara, M. Hoshi, M. Ishikawa et K. Shizuma. « A Monte Carlo track structure code for low energy protons ». Nuclear Instruments and Methods in Physics Research Section B : Beam Interactions with Materials and Atoms 194, no 2 (août 2002) : 123–31. http://dx.doi.org/10.1016/s0168-583x(02)00497-4.

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Pater, Piotr, Jan Seuntjens, Issam El Naqa et Mario A. Bernal. « On the consistency of Monte Carlo track structure DNA damage simulations ». Medical Physics 41, no 12 (18 novembre 2014) : 121708. http://dx.doi.org/10.1118/1.4901555.

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Díaz-Díaz, Jorge A., Eugenio Torres-García, Rigoberto Oros-Pantoja, Liliana Aranda Lara et Patricia Vieyra-Reyes. « New track-structure Monte Carlo code for 4D ionizing photon transport ». Radiation Effects and Defects in Solids 173, no 7-8 (28 juin 2018) : 567–77. http://dx.doi.org/10.1080/10420150.2018.1484744.

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Pasciak, A. S., et J. R. Ford. « High-speed evaluation of track-structure Monte Carlo electron transport simulations ». Physics in Medicine and Biology 53, no 19 (9 septembre 2008) : 5539–53. http://dx.doi.org/10.1088/0031-9155/53/19/018.

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Emfietzoglou, D., A. Akkerman et J. Barak. « New Monte Carlo calculations of charged particle track-structure in silicon ». IEEE Transactions on Nuclear Science 51, no 5 (octobre 2004) : 2872–79. http://dx.doi.org/10.1109/tns.2004.835061.

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Nikjoo, H., P. O'Neill, M. Terrissol et D. T. Goodhead. « Quantitative modelling of DNA damage using Monte Carlo track structure method ». Radiation and Environmental Biophysics 38, no 1 (12 mai 1999) : 31–38. http://dx.doi.org/10.1007/s004110050135.

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Sattinger, D., et Y. S. Horowitz. « Track structure calculations in LiF:Mg,Ti : A Monte Carlo study of the ‘track escape’ parameter ». Radiation Measurements 43, no 2-6 (février 2008) : 185–89. http://dx.doi.org/10.1016/j.radmeas.2007.12.024.

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Uehara, Shuzo, et Hooshang Nikjoo. « Monte Carlo Track Structure Code for Low-Energy Alpha-Particles in Water ». Journal of Physical Chemistry B 106, no 42 (octobre 2002) : 11051–63. http://dx.doi.org/10.1021/jp014004h.

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Quiroga, L. M., et E. Schnieder. « Monte Carlo simulation of railway track geometry deterioration and restoration ». Proceedings of the Institution of Mechanical Engineers, Part O : Journal of Risk and Reliability 226, no 3 (1 décembre 2011) : 274–82. http://dx.doi.org/10.1177/1748006x11418422.

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Travelling safely and comfortably on high-speed railway lines requires excellent conditions of the whole railway infrastructure in general and of the railway track geometry in particular. The maintenance process required to achieve such excellent conditions is complex and expensive, demanding a large amount of both human and technical resources. In this framework, choosing the right maintenance strategy becomes a critical issue. A reliable simulation of the railway geometry ageing process would offer a great advantage for the optimization of planning and scheduling of maintenance activities. A fundamental requirement for such simulation is a statistical model describing the behaviour of the railway track geometry deterioration as well as the effects of maintenance activities. The French railway operator SNCF has been periodically measuring the geometrical characteristics of its high-speed network since its commissioning (i.e. for more than 20 years now). These records are an excellent data source to achieve a sound statistical description of the process. In this paper a new system identification method to obtain such simulations is presented. The proposed method uses a grey-box model: a model structure and its constraints are specified basing on previous knowledge of the process to be identified, and then the set of parameter values which best fits the signal measurements is searched. As previous knowledge indicates that the process is non-linear, parameter values are searched by means of the Levenberg–Marquardt algorithm, an iterative technique that finds a local minimum of a function that is expressed as the sum of squares of non-linear functions. Furthermore, the presented model is extended in order to analyse the effect of the variation of factors influencing the ageing process (e.g. operational speed). Finally, the method is applied and validated with real data of a French high-speed TGV line.
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Podwórna, M. « Modelling Of Random Vertical Irregularities Of Railway Tracks ». International Journal of Applied Mechanics and Engineering 20, no 3 (1 août 2015) : 647–55. http://dx.doi.org/10.1515/ijame-2015-0043.

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Abstract The study presents state-of-the-art in analytical and numerical modelling of random vertical irregularities of continuously welded ballasted railway tracks. The common model of railway track irregularity vertical profiles is applied, in the form of a stationary and ergodic Gaussian process in space. Random samples of track irregularity vertical profiles are generated with the Monte-Carlo method. Based on the numerical method developed in the study, the minimum and recommended sampling number required in the random analysis of railway bridges and number of frequency increments (harmonic components) in track irregularity vertical profiles simulation are determined. The lower and upper limits of wavelengths are determined based on the literature studies. The approach yields track irregularity random samples close to reality. The track irregularity model developed in the study can be used in the dynamic analysis of railway bridge / track structure / highspeed train systems.
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Champion, Christophe, Mouhamad Elbast, Ting-Di Wu et Nicole Colas-Linhart. « Thyroid cell irradiation by radioiodines : a new Monte Carlo electron track-structure code ». Brazilian Archives of Biology and Technology 50, spe (septembre 2007) : 135–44. http://dx.doi.org/10.1590/s1516-89132007000600017.

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The most significant impact of the Chernobyl accident is the increased incidence of thyroid cancer among children who were exposed to short-lived radioiodines and 131-iodine. In order to accurately estimate the radiation dose provided by these radioiodines, it is necessary to know where iodine is incorporated. To do that, the distribution at the cellular level of newly organified iodine in the immature rat thyroid was performed using secondary ion mass microscopy (NanoSIMS50). Actual dosimetric models take only into account the averaged energy and range of beta particles of the radio-elements and may, therefore, imperfectly describe the real distribution of dose deposit at the microscopic level around the point sources. Our approach is radically different since based on a track-structure Monte Carlo code allowing following-up of electrons down to low energies (~ 10eV) what permits a nanometric description of the irradiation physics. The numerical simulations were then performed by modelling the complete disintegrations of the short-lived iodine isotopes as well as of 131I in new born rat thyroids in order to take into account accurate histological and biological data for the thyroid gland.
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Hilgers, G., M. U. Bug, E. Gargioni et H. Rabus. « Comparison of measured and Monte Carlo simulated track structure parameters in nanometric volumes ». Radiation Protection Dosimetry 161, no 1-4 (13 novembre 2013) : 441–44. http://dx.doi.org/10.1093/rpd/nct265.

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Uehara, Shuzo, Hooshang Nikjoo et Dudley T. Goodhead. « Comparison and Assessment of Electron Cross Sections for Monte Carlo Track Structure Codes ». Radiation Research 152, no 2 (août 1999) : 202. http://dx.doi.org/10.2307/3580095.

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Vandoorne, Rick, et Petrus J. Gräbe. « Stochastic rail life cycle cost maintenance modelling using Monte Carlo simulation ». Proceedings of the Institution of Mechanical Engineers, Part F : Journal of Rail and Rapid Transit 232, no 4 (13 juin 2017) : 1240–51. http://dx.doi.org/10.1177/0954409717714645.

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The need for decision support systems to guide maintenance and renewal decisions for infrastructure is growing due to tighter budget requirements and the concurrent need to satisfy reliability, availability and safety requirements. The rail of the railway track is one of the most important components of the entire track structure and can significantly influence maintenance costs throughout the life cycle of the track. Estimation of life cycle cost is a popular decision support system. A calculated life cycle cost has inherent uncertainty associated with the reliability of the input data used in such a model. A stochastic life cycle cost model was developed for the rail of the railway track incorporating imperfect inspections. The model was implemented using Monte Carlo simulation in order to allow quantification of the associated uncertainty within the life cycle cost calculated. For a given set of conditions, an optimal renewal tonnage exists at which the rail should be renewed in order to minimise the mean life cycle cost. The optimal renewal tonnage and minimum attainable mean life cycle cost are dependent on the length of inspection interval, weld type used for maintenance as well as the cost of maintenance and inspection activities. It was found that the distribution of life cycle cost for a fixed renewal tonnage followed a log-normal probability distribution. The standard deviation of this distribution can be used as a metric to quantify uncertainty. Uncertainty increases with an increase in the length of inspection interval for a fixed rail renewal tonnage. With all other conditions fixed, it was found that the uncertainty in life cycle cost increases with an increase in the rail renewal tonnage. The relative contribution of uncertainty of the planned and unplanned maintenance costs towards the uncertainty in total life cycle cost was found to be dependent on the length of inspection interval.
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17

Liamsuwan, T., S. Uehara et H. Nikjoo. « Microdosimetry of the full slowing down of protons using Monte Carlo track structure simulations ». Radiation Protection Dosimetry 166, no 1-4 (22 avril 2015) : 29–33. http://dx.doi.org/10.1093/rpd/ncv204.

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Tajik-Mansoury, M. A., H. Rajabi et H. Mozdarani. « A comparison between track-structure, condensed-history Monte Carlo simulations and MIRD cellularS-values ». Physics in Medicine and Biology 62, no 5 (9 février 2017) : N90—N106. http://dx.doi.org/10.1088/1361-6560/62/5/n90.

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Champion, C., A. L'Hoir, M. F. Politis, A. Chetioui, B. Fayard et A. Touati. « Monte-Carlo simulation of ion track structure in water : ionization clusters and biological effectiveness ». Nuclear Instruments and Methods in Physics Research Section B : Beam Interactions with Materials and Atoms 146, no 1-4 (décembre 1998) : 533–40. http://dx.doi.org/10.1016/s0168-583x(98)00438-8.

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Uehara, S., L. H. Toburen et H. Nikjoo. « Development of a Monte Carlo track structure code for low-energy protons in water ». International Journal of Radiation Biology 77, no 2 (janvier 2001) : 139–54. http://dx.doi.org/10.1080/09553000010012536.

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Champion, C., et C. Le Loirec. « Positron follow-up in liquid water : I. A new Monte Carlo track-structure code ». Physics in Medicine and Biology 51, no 7 (7 mars 2006) : 1707–23. http://dx.doi.org/10.1088/0031-9155/51/7/005.

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Batmunkh, Munkhbaatar, Lkhagvaa Bayarchimeg, Aleksandr N. Bugay et Oidov Lkhagva. « Monte Carlo track structure simulation in studies of biological effects induced by accelerated charged particles in the central nervous system ». EPJ Web of Conferences 204 (2019) : 04008. http://dx.doi.org/10.1051/epjconf/201920404008.

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Simulating the biological damage induced by charged particles trajectories (tracks) in the central nervous system (CNS) at different levels of its organization (molecular, cellular, and tissue) is a challenge of modern radiobiology studies. According to the recent experimental studies at particle accelerators, the most radiation-sensitive area of the CNS is the hippocampus. In this regards, the development of measurement-based Monte Carlo simulation of radiation-induced alterations in the hippocampus is of great interest to understand the radiobiological effects on the CNS. The present work investigates the influence of charged particles on the hippocampal cells of the rat brain using the Geant4 Monte Carlo radiation transport code. The applied computer simulation provides a method to simulate physics processes and chemical reactions in the developed model of the rat hippocampus, which contains different types of neural cells - pyramidal cells, mature and immature granular cells, mossy cells, and neural stem cells. The distribution of stochastic energy depositions has been obtained and analyzed in critical structures of the hippocampal neurons after irradiation with 600 MeV/u iron particles. The computed energy deposition in irradiated hippocampal neurons following a track of iron ion suggests that most of the energy is accumulated by granular cells. The obtained quantities at the level of molecular targets also assume that NMDA and GABA receptors belong to the most probable targets in the irradiated neural cells.
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Francis, Z., S. Incerti, R. Capra, B. Mascialino, G. Montarou, V. Stepan et C. Villagrasa. « Molecular scale track structure simulations in liquid water using the Geant4-DNA Monte-Carlo processes ». Applied Radiation and Isotopes 69, no 1 (janvier 2011) : 220–26. http://dx.doi.org/10.1016/j.apradiso.2010.08.011.

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Nikjoo, H., D. E. Charlton et D. T. Goodhead. « Monte Carlo track structure studies of energy deposition and calculation of initial DSB and RBE ». Advances in Space Research 14, no 10 (octobre 1994) : 161–80. http://dx.doi.org/10.1016/0273-1177(94)90466-9.

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Champion, Christophe. « Moving from organ dose to microdosimetry : contribution of the Monte Carlo simulations ». Brazilian Archives of Biology and Technology 48, spe2 (octobre 2005) : 191–99. http://dx.doi.org/10.1590/s1516-89132005000700029.

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When living cells are irradiated by charged particles, a wide variety of interactions occurs that leads to a deep modification of the biological material. To understand the fine structure of the microscopic distribution of the energy deposits, Monte Carlo event-by-event simulations are particularly suitable. However, the development of these track structure codes needs accurate interaction cross sections for all the electronic processes: ionization, excitation, Positronium formation (for incident positrons) and even elastic scattering. Under these conditions, we have recently developed a Monte Carlo code for electrons and positrons in water, this latter being commonly used to simulate the biological medium. All the processes are studied in detail via theoretical differential and total cross sections calculated by using partial wave methods. Comparisons with existing theoretical and experimental data show very good agreements. Moreover, this kind of detailed description allows one access to a useful microdosimetry, which can be coupled to a geometrical modelling of the target organ and then provide a detailed dose calculation at the nanometric scale.
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Batmunkh, Munkhbaatar, Alexander Bugay, Lkhagvaa Bayarchimeg et Oidov Lkhagva. « Radiation Damage to Nervous System : Designing Optimal Models for Realistic Neuron Morphology in Hippocampus ». EPJ Web of Conferences 173 (2018) : 05004. http://dx.doi.org/10.1051/epjconf/201817305004.

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The present study is focused on the development of optimal models of neuron morphology for Monte Carlo microdosimetry simulations of initial radiation-induced events of heavy charged particles in the specific types of cells of the hippocampus, which is the most radiation-sensitive structure of the central nervous system. The neuron geometry and particles track structures were simulated by the Geant4/Geant4-DNA Monte Carlo toolkits. The calculations were made for beams of protons and heavy ions with different energies and doses corresponding to real fluxes of galactic cosmic rays. A simple compartmental model and a complex model with realistic morphology extracted from experimental data were constructed and compared. We estimated the distribution of the energy deposition events and the production of reactive chemical species within the developed models of CA3/CA1 pyramidal neurons and DG granule cells of the rat hippocampus under exposure to different particles with the same dose. Similar distributions of the energy deposition events and concentration of some oxidative radical species were obtained in both the simplified and realistic neuron models.
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Wang, Xiu Fang, Jin Ye Peng, Bin Chen et Wei Qi. « Tracking Algorithm Design and Comparison of High Speed High Maneuvering Target ». Applied Mechanics and Materials 713-715 (janvier 2015) : 2053–57. http://dx.doi.org/10.4028/www.scientific.net/amm.713-715.2053.

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Aiming at the problem that the traditional tracking method cannot track high speed high maneuvering target effectively, one modified fixed structure multiple model algorithm (M-FSMM) and one modified variable structure multiple model (M-VSMM) algorithm were proposed. The Constant Velocity (CV) model, Current Statistical (CS) and Modified Coordinate Turn (MCT) model were adopted in the M-FSMM algorithm, by means of Connected Graph (CG) thinking, the model connected graph was made up by models that can describe possible motion, the connected relation was set up and model self-adapting was designed to carry out the variable structure tracking that can quickly jump between models. Monte Carlo simulation results show that the two methods can track high speed high maneuvering target effectively, the computational quantum of M-FVMM algorithm is larger but the tracking accuracy and stability are better than the M-FSMM algorithm. They can be used to track near space hypersonic targets.
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Nikjoo, Hooshang, Dimitris Emfietzoglou, Ritsuko Watanabe et Shuzo Uehara. « Can Monte Carlo track structure codes reveal reaction mechanism in DNA damage and improve radiation therapy ? » Radiation Physics and Chemistry 77, no 10-12 (octobre 2008) : 1270–79. http://dx.doi.org/10.1016/j.radphyschem.2008.05.043.

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Watanabe, Ritsuko, Shirin Rahmanian et Hooshang Nikjoo. « Spectrum of Radiation-Induced Clustered Non-DSB Damage – A Monte Carlo Track Structure Modeling and Calculations ». Radiation Research 183, no 5 (mai 2015) : 525–40. http://dx.doi.org/10.1667/rr13902.1.

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Emfietzoglou, Dimitris, George Papamichael et Hooshang Nikjoo. « Monte Carlo Electron Track Structure Calculations in Liquid Water Using a New Model Dielectric Response Function ». Radiation Research 188, no 3 (septembre 2017) : 355–68. http://dx.doi.org/10.1667/rr14705.1.

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Zhao, X. F., et S. X. Huang. « Using particle filter to track horizontal variations of atmospheric duct structure from radar sea clutter ». Atmospheric Measurement Techniques Discussions 5, no 4 (23 août 2012) : 6059–82. http://dx.doi.org/10.5194/amtd-5-6059-2012.

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Abstract. This paper addresses the problem of estimating range-varying parameters of the height-dependent refractivity over the sea surface from radar sea clutter. In the forward simulation, the split-step Fourier parabolic equation (PE) is used to compute the radar clutter power in the complex refractive environments. Making use of the inherent Markovian structure of the split-step Fourier PE solution, the refractivity from clutter (RFC) problem is formulated within a nonlinear recursive Bayesian state estimation framework. Particle filter (PF) that is a technique for implementing a recursive Bayesian filter by Monte Carlo simulations is used to track range-varying characteristics of the refractivity profiles. Basic ideas of employing PF to solve RFC problem are introduced. Both simulation and real data results are presented to check up the feasibility of PF-RFC performances.
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Zhao, X. F., S. X. Huang et D. X. Wang. « Using particle filter to track horizontal variations of atmospheric duct structure from radar sea clutter ». Atmospheric Measurement Techniques 5, no 11 (26 novembre 2012) : 2859–66. http://dx.doi.org/10.5194/amt-5-2859-2012.

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Abstract. This paper addresses the problem of estimating range-varying parameters of the height-dependent refractivity over the sea surface from radar sea clutter. In the forward simulation, the split-step Fourier parabolic equation (PE) is used to compute the radar clutter power in the complex refractive environments. Making use of the inherent Markovian structure of the split-step Fourier PE solution, the refractivity from clutter (RFC) problem is formulated within a nonlinear recursive Bayesian state estimation framework. Particle filter (PF), which is a technique for implementing a recursive Bayesian filter by Monte Carlo simulations, is used to track range-varying characteristics of the refractivity profiles. Basic ideas of employing PF to solve RFC problem are introduced. Both simulation and real data results are presented to confirm the feasibility of PF-RFC performances.
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Lazarakis, P., M. U. Bug, E. Gargioni, S. Guatelli, H. Rabus et A. B. Rosenfeld. « Comparison of nanodosimetric parameters of track structure calculated by the Monte Carlo codes Geant4-DNA and PTra ». Physics in Medicine and Biology 57, no 5 (14 février 2012) : 1231–50. http://dx.doi.org/10.1088/0031-9155/57/5/1231.

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Bug, M. U., E. Gargioni, S. Guatelli, S. Incerti, H. Rabus, R. Schulte et A. B. Rosenfeld. « Effect of a magnetic field on the track structure of low-energy electrons : a Monte Carlo study ». European Physical Journal D 60, no 1 (26 mai 2010) : 85–92. http://dx.doi.org/10.1140/epjd/e2010-00145-1.

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Hu, Ankang, Wanyi Zhou, Zhen Wu, Hui Zhang, Junli Li et Rui Qiu. « Modeling of DNA Damage Repair and Cell Response in Relation to p53 System Exposed to Ionizing Radiation ». International Journal of Molecular Sciences 23, no 19 (26 septembre 2022) : 11323. http://dx.doi.org/10.3390/ijms231911323.

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Repair of DNA damage induced by ionizing radiation plays an important role in the cell response to ionizing radiation. Radiation-induced DNA damage also activates the p53 system, which determines the fate of cells. The kinetics of repair, which is affected by the cell itself and the complexity of DNA damage, influences the cell response and fate via affecting the p53 system. To mechanistically study the influences of the cell response to different LET radiations, we introduce a new repair module and a p53 system model with NASIC, a Monte Carlo track structure code. The factors determining the kinetics of the double-strand break (DSB) repair are modeled, including the chromosome environment and complexity of DSB. The kinetics of DSB repair is modeled considering the resection-dependent and resection-independent compartments. The p53 system is modeled by simulating the interactions among genes and proteins. With this model, the cell responses to low- and high-LET irradiation are simulated, respectively. It is found that the kinetics of DSB repair greatly affects the cell fate and later biological effects. A large number of DSBs and a slow repair process lead to severe biological consequences. High-LET radiation induces more complex DSBs, which can be repaired by slow processes, subsequently resulting in a longer cycle arrest and, furthermore, apoptosis and more secreting of TGFβ. The Monte Carlo track structure simulation with a more realistic repair module and the p53 system model developed in this study can expand the functions of the NASIC code in simulating mechanical radiobiological effects.
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Ali, Yasmine, Caterina Monini, Etienne Russeil, Jean Michel Létang, Etienne Testa, Lydia Maigne et Michael Beuve. « Estimate of the Biological Dose in Hadrontherapy Using GATE ». Cancers 14, no 7 (25 mars 2022) : 1667. http://dx.doi.org/10.3390/cancers14071667.

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For the evaluation of the biological effects, Monte Carlo toolkits were used to provide an RBE-weighted dose using databases of survival fraction coefficients predicted through biophysical models. Biophysics models, such as the mMKM and NanOx models, have previously been developed to estimate a biological dose. Using the mMKM model, we calculated the saturation corrected dose mean specific energy z1D* (Gy) and the dose at 10% D10 for human salivary gland (HSG) cells using Monte Carlo Track Structure codes LPCHEM and Geant4-DNA, and compared these with data from the literature for monoenergetic ions. These two models were used to create databases of survival fraction coefficients for several ion types (hydrogen, carbon, helium and oxygen) and for energies ranging from 0.1 to 400 MeV/n. We calculated α values as a function of LET with the mMKM and the NanOx models, and compared these with the literature. In order to estimate the biological dose for SOBPs, these databases were used with a Monte Carlo toolkit. We considered GATE, an open-source software based on the GEANT4 Monte Carlo toolkit. We implemented a tool, the BioDoseActor, in GATE, using the mMKM and NanOx databases of cell survival predictions as input, to estimate, at a voxel scale, biological outcomes when treating a patient. We modeled the HIBMC 320 MeV/u carbon-ion beam line. We then tested the BioDoseActor for the estimation of biological dose, the relative biological effectiveness (RBE) and the cell survival fraction for the irradiation of the HSG cell line. We then tested the implementation for the prediction of cell survival fraction, RBE and biological dose for the HIBMC 320 MeV/u carbon-ion beamline. For the cell survival fraction, we obtained satisfying results. Concerning the prediction of the biological dose, a 10% relative difference between mMKM and NanOx was reported.
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Derksen, Larissa, Tabea Pfuhl, Rita Engenhart-Cabillic, Klemens Zink et Kilian-Simon Baumann. « Investigating the feasibility of TOPAS-nBio for Monte Carlo track structure simulations by adapting GEANT4-DNA examples application ». Physics in Medicine & ; Biology 66, no 17 (31 août 2021) : 175023. http://dx.doi.org/10.1088/1361-6560/ac1d21.

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Bug, M. U., H. Rabus et A. B. Rosenfeld. « Electron emission from amorphous solid water after proton impact : Benchmarking PTra and Geant4 track structure Monte Carlo simulations ». Radiation Physics and Chemistry 81, no 12 (décembre 2012) : 1804–12. http://dx.doi.org/10.1016/j.radphyschem.2012.07.006.

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Thibaut, Yann, Nicolas Tang, Hoang Ngoc Tran, Aurélie Vaurijoux, Carmen Villagrasa, Sébastien Incerti et Yann Perrot. « Nanodosimetric Calculations of Radiation-Induced DNA Damage in a New Nucleus Geometrical Model Based on the Isochore Theory ». International Journal of Molecular Sciences 23, no 7 (29 mars 2022) : 3770. http://dx.doi.org/10.3390/ijms23073770.

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Double-strand breaks (DSBs) in nuclear DNA represents radiation-induced damage that has been identified as particularly deleterious. Calculating this damage using Monte Carlo track structure modeling could be a suitable indicator to better assess and anticipate the side-effects of radiation therapy. However, as already demonstrated in previous work, the geometrical description of the nucleus and the DNA content used in the simulation significantly influence damage calculations. Therefore, in order to obtain accurate results, this geometry must be as realistic as possible. In this study, a new geometrical model of an endothelial cell nucleus and DNA distribution according to the isochore theory are presented and used in a Monte Carlo simulation chain based on the Geant4-DNA toolkit. In this theory, heterochromatin and euchromatin compaction are distributed along the genome according to five different families (L1, L2, H1, H2, and H3). Each of these families is associated with a different hetero/euchromatin rate related to its compaction level. In order to compare the results with those obtained using a previous nuclear geometry, simulations were performed for protons with linear energy transfers (LETs) of 4.29 keV/µm, 19.51 keV/µm, and 43.25 keV/µm. The organization of the chromatin fibers at different compaction levels linked to isochore families increased the DSB yield by 6–10%, and it allowed the most affected part of the genome to be identified. These new results indicate that the genome core is more radiosensitive than the genome desert, with a 3–8% increase in damage depending on the LET. This work highlights the importance of using realistic distributions of chromatin compaction levels to calculate radio-induced damage using Monte Carlo simulation methods.
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40

Rymzhanov, R. A. « ELECTRON KINETICS OF YTTRIUM IRON GARNET AFTER SWIFT HEAVY ION IMPACT ». Eurasian Physical Technical Journal 19, no 3 (41) (22 septembre 2022) : 23–28. http://dx.doi.org/10.31489/2022no3/23-28.

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The TREKIS Monte-Carlo model was applied to study the temporal electronic kinetics of yttrium iron garnet after a swift heavy ion impact. Cross sections of incident particles interaction with the target were determined within complex dielectric function-dynamic structure factor formalism. We found two modes of the spatial propagation of electronic excitation: fast delta-electrons form a front of the excitation while electrons produced due to decay of plasmons generated in a track form the second front slowly following behind the first one.Analysis of mechanisms of target lattice heating pointed to an important contribution of the potential energy released due to recombination of valence holes generated in an ion track. An increase of the excess lattice energy due to elastic scatterings of electrons and holes described with Mott cross-sections is minor. In contrast, complex dielectric function formalism demonstrates the significant contribution of these processes to the heating of the lattice.
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Rucinski, Antoni, Anna Biernacka et Reinhard Schulte. « Applications of nanodosimetry in particle therapy planning and beyond ». Physics in Medicine & ; Biology 66, no 24 (10 décembre 2021) : 24TR01. http://dx.doi.org/10.1088/1361-6560/ac35f1.

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Abstract This topical review summarizes underlying concepts of nanodosimetry. It describes the development and current status of nanodosimetric detector technology. It also gives an overview of Monte Carlo track structure simulations that can provide nanodosimetric parameters for treatment planning of proton and ion therapy. Classical and modern radiobiological assays that can be used to demonstrate the relationship between the frequency and complexity of DNA lesion clusters and nanodosimetric parameters are reviewed. At the end of the review, existing approaches of treatment planning based on relative biological effectiveness (RBE) models or dose-averaged linear energy transfer are contrasted with an RBE-independent approach based on nandosimetric parameters. Beyond treatment planning, nanodosimetry is also expected to have applications and give new insights into radiation protection dosimetry.
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Uehara, S., H. Nikjoo et D. T. Goodhead. « Cross-sections for water vapour for the Monte Carlo electron track structure code from 10 eV to the MeV region ». Physics in Medicine and Biology 38, no 12 (1 décembre 1993) : 1841–58. http://dx.doi.org/10.1088/0031-9155/38/12/010.

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Matsuya, Yusuke, Takeshi Kai, Yuji Yoshii, Yoshie Yachi, Shingo Naijo, Hiroyuki Date et Tatsuhiko Sato. « Modeling of yield estimation for DNA strand breaks based on Monte Carlo simulations of electron track structure in liquid water ». Journal of Applied Physics 126, no 12 (28 septembre 2019) : 124701. http://dx.doi.org/10.1063/1.5115519.

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44

Lucido, J., I. Popescu et V. Moiseenko. « SU-E-T-81 : Comparison of Microdosimetric Quantities Calculated Using the Track Structure Monte Carlo Algorithms Geant4-DNA and NOREC ». Medical Physics 41, no 6Part12 (29 mai 2014) : 240. http://dx.doi.org/10.1118/1.4888411.

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Boscolo, Daria, Michael Krämer, Martina C. Fuss, Marco Durante et Emanuele Scifoni. « Impact of Target Oxygenation on the Chemical Track Evolution of Ion and Electron Radiation ». International Journal of Molecular Sciences 21, no 2 (9 janvier 2020) : 424. http://dx.doi.org/10.3390/ijms21020424.

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The radiosensitivity of biological systems is strongly affected by the system oxygenation. On the nanoscopic scale and molecular level, this effect is considered to be strongly related to the indirect damage of radiation. Even though particle track radiolysis has been the object of several studies, still little is known about the nanoscopic impact of target oxygenation on the radical yields. Here we present an extension of the chemical module of the Monte Carlo particle track structure code TRAX, taking into account the presence of dissolved molecular oxygen in the target material. The impact of the target oxygenation level on the chemical track evolution and the yields of all the relevant chemical species are studied in water under different irradiation conditions: different linear energy transfer (LET) values, different oxygenation levels, and different particle types. Especially for low LET radiation, a large production of two highly toxic species ( HO 2 • and O 2 • − ), which is not produced in anoxic conditions, is predicted and quantified in oxygenated solutions. The remarkable correlation between the HO 2 • and O 2 • − production yield and the oxygen enhancement ratio observed in biological systems suggests a direct or indirect involvement of HO 2 • and O 2 • − in the oxygen sensitization effect. The results are in agreement with available experimental data and previous computational approaches. An analysis of the oxygen depletion rate in different radiation conditions is also reported. The radiosensitivity of biological systems is strongly affected by the system oxygenation. On the nanoscopic scale and molecular level, this effect is considered to be strongly related to the indirect damage of radiation. Even though particle track radiolysis has been the object of several studies, still little is known about the nanoscopic impact of target oxygenation on the radical yields. Here we present an extension of the chemical module of the Monte Carlo particle track structure code TRAX, taking into account the presence of dissolved molecular oxygen in the target material. The impact of the target oxygenation level on the chemical track evolution and the yields of all the relevant chemical species are studied in water under different irradiation conditions: different linear energy transfer (LET) values, different oxygenation levels, and different particle types. Especially for low LET radiation, a large production of two highly toxic species ( HO 2 • and O 2 • − ), which is not produced in anoxic conditions, is predicted and quantified in oxygenated solutions. The remarkable correlation between the HO 2 • and O 2 • − production yield and the oxygen enhancement ratio observed in biological systems suggests a direct or indirect involvement of HO 2 • and O 2 • − in the oxygen sensitization effect. The results are in agreement with available experimental data and previous computational approaches. An analysis of the oxygen depletion rate in different radiation conditions is also reported.
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Thompson, Shannon J., Aoife Rooney, Kevin M. Prise et Stephen J. McMahon. « Evaluating Iodine-125 DNA Damage Benchmarks of Monte Carlo DNA Damage Models ». Cancers 14, no 3 (18 janvier 2022) : 463. http://dx.doi.org/10.3390/cancers14030463.

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A wide range of Monte Carlo models have been applied to predict yields of DNA damage based on nanoscale track structure calculations. While often similar on the macroscopic scale, these models frequently employ different assumptions which lead to significant differences in nanoscale dose deposition. However, the impact of these differences on key biological readouts remains unclear. A major challenge in this area is the lack of robust datasets which can be used to benchmark models, due to a lack of resolution at the base pair level required to deeply test nanoscale dose deposition. Studies investigating the distribution of strand breakage in short DNA strands following the decay of incorporated 125I offer one of the few benchmarks for model predictions on this scale. In this work, we have used TOPAS-nBio to evaluate the performance of three Geant4-DNA physics models at predicting the distribution and yield of strand breaks in this irradiation scenario. For each model, energy and OH radical distributions were simulated and used to generate predictions of strand breakage, varying energy thresholds for strand breakage and OH interaction rates to fit to the experimental data. All three models could fit well to the observed data, although the best-fitting strand break energy thresholds ranged from 29.5 to 32.5 eV, significantly higher than previous studies. However, despite well describing the resulting DNA fragment distribution, these fit models differed significantly with other endpoints, such as the total yield of breaks, which varied by 70%. Limitations in the underlying data due to inherent normalisation mean it is not possible to distinguish clearly between the models in terms of total yield. This suggests that, while these physics models can effectively fit some biological data, they may not always generalise in the same way to other endpoints, requiring caution in their extrapolation to new systems and the use of multiple different data sources for robust model benchmarking.
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Van der Ven, A., J. C. Thomas, B. Puchala et A. R. Natarajan. « First-Principles Statistical Mechanics of Multicomponent Crystals ». Annual Review of Materials Research 48, no 1 (juillet 2018) : 27–55. http://dx.doi.org/10.1146/annurev-matsci-070317-124443.

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The importance of configurational, vibrational, and electronic excitations in crystalline solids of technological interest makes a rigorous treatment of thermal excitations an essential ingredient in first-principles models of materials behavior. This contribution reviews statistical mechanics approaches that connect a crystal's electronic structure to its thermodynamic and kinetic properties. We start with a description of a thermodynamic and kinetic framework for multicomponent crystals that integrates chemistry and mechanics, as well as nonconserved order parameters that track the degree of chemical order and group/subgroup structural distortions. The framework allows for spatial heterogeneities and naturally couples thermodynamics with kinetics. We next survey statistical mechanics approaches that rely on effective Hamiltonians to treat configurational, vibrational, and electronic degrees of freedom within multicomponent crystals. These Hamiltonians, when suitably constructed, are capable of extrapolating first-principles electronic structure calculations within (kinetic) Monte Carlo simulations, thereby enabling first-principles predictions of equilibrium and nonequilibrium materials properties at finite temperature.
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Hannachi, Essia, M. I. Sayyed, Suhairul Hashim, Karem Mahmoud et Yassine Slimani. « Theoretical Examination of the Radiation Protecting Properties of CaTiO3 Material Sintered at Different Temperatures ». Crystals 13, no 1 (10 janvier 2023) : 120. http://dx.doi.org/10.3390/cryst13010120.

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This research is devoted to studying the radiation-protecting characteristics of calcium titanate (CaTiO3) perovskite-based ceramic material. The ceramics were made by the solid-state reaction method (SSRM) and treated at temperatures of 1300 °C, 1200 °C, and 1100 °C. The structural characteristics of the ceramics were analyzed by XRD and FT-IR. The results indicated a CaTiO3 phase formation with an orthorhombic structure. The size of the crystallites was in the range of 27–36 nm and was found to increase as the temperatures increased. The relative density showed an increase from 93% to 96% as the temperatures varied from 1100 °C to 1300 °C. The impact of temperature on the radiation-protecting characteristics of the CaTiO3 ceramic was assessed using the Monte Carlo simulation (MCS). There was a slight decrease in the γ-photons average track length with a raising of the temperature. At a γ-photon energy of 0.662 MeV, the γ-photons’ average track lengths diminished from 3.52 cm to 3.38 cm by raising the temperature from 1100 °C to 1300 °C. The illustrated decrease in the γ-photons average track length affected the linear attenuation coefficient (µ) where the µ increased from 0.28 to 0.30 cm−1 with a rising temperature from 1100 °C to 1300 °C.
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Carrasco-Hernández, J., J. Ramos-Méndez, B. Faddegon, A. R. Jalilian, M. Moranchel et M. A. Ávila-Rodríguez. « Monte Carlo track-structure for the radionuclide Copper-64 : characterization of S-values, nanodosimetry and quantification of direct damage to DNA ». Physics in Medicine & ; Biology 65, no 15 (27 juillet 2020) : 155005. http://dx.doi.org/10.1088/1361-6560/ab8aaa.

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Lee, B., et C. Wang. « WE-H-BRA-08 : A Monte Carlo Cell Nucleus Model for Assessing Cell Survival Probability Based On Particle Track Structure Analysis ». Medical Physics 43, no 6Part43 (juin 2016) : 3844. http://dx.doi.org/10.1118/1.4957999.

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