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Special Issue "Electron and Radical Induced Chemistry with Radiobiological Applications"

A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Physical Chemistry and Chemical Physics".

Deadline for manuscript submissions: closed (30 September 2022) | Viewed by 4188

Special Issue Editor

1. CSIC - Instituto de Fisica Fundamental (IFF), Madrid, Spain
2. Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, Australia
Interests: electron; positron and ion collisions; radiation damage; molecular biophysics

Special Issue Information

Dear Colleagues,

New biomedical applications of radiation based on charged particle beam interactions, both for therapy (proton therapy, heavy ion-beam radiation therapy, intraoperational electron beam therapies) and diagnostics (Positron Emission Tomography) require specific studies on their radiobiological effects. In such applications, secondary species (very low-energy secondary electrons and reactive radicals) determine these effects through chemical reactions induced to the sensitive molecules that constitute the medium.

The scope of this Special Issue (in terms of theory, experiments and simulations) includes:

  • Primary proton and ion beam interactions in biologically relevant media around the Bragg Peak.
  • Chemical reactions induced by low-energy electrons and positrons to biomolecular systems both in the gas and condensed phases.
  • Radical generation and subsequent interactions with molecular-sensitive molecules (DNA, RNA constituents and analogue molecules).
  • Evaluation and characterization of molecular radiosensitizers and their role in specific treatments.
  • Living cell radiobiological studies and comparison with predicted models.

Due to your expertise in the field, we are pleased to invite you to contribute to this Special Issue on Electron and Radical Induced Chemistry with Radiobiological Applications.

Prof. Dr. Gustavo Garcia
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. International Journal of Molecular Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. There is an Article Processing Charge (APC) for publication in this open access journal. For details about the APC please see here. Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • ion beam interaction with biomoles
  • low energy electrons and positron interactions
  • reactive species
  • modelling particle transport
  • molecular radiosensitizers
  • molecular-damaging reactions
  • ion beam radiotherapy
  • intraoperational electron beam therapy
  • radiobiological studies

Published Papers (5 papers)

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Research

Article
Track Structure of Light Ions: The Link to Radiobiology
Int. J. Mol. Sci. 2023, 24(6), 5826; https://doi.org/10.3390/ijms24065826 - 18 Mar 2023
Viewed by 221
Abstract
It is generally recognized that the biological response to irradiation by light ions is initiated by complex damages at the DNA level. In turn, the occurrence of complex DNA damages is related to spatial and temporal distribution of ionization and excitation events, i.e., [...] Read more.
It is generally recognized that the biological response to irradiation by light ions is initiated by complex damages at the DNA level. In turn, the occurrence of complex DNA damages is related to spatial and temporal distribution of ionization and excitation events, i.e., the particle track structure. It is the aim of the present study to investigate the correlation between the distribution of ionizations at the nanometric scale and the probability to induce biological damage. By means of Monte Carlo track structure simulations, the mean ionization yield M1 and the cumulative probabilities F1, F2, and F3 of at least one, two and three ionizations, respectively, were calculated in spherical volumes of water-equivalent diameters equal to 1, 2, 5 and 10 nm. When plotted as a function of M1, the quantities F1, F2 and F3 are distributed along almost unique curves, largely independent of particle type and velocity. However, the shape of the curves depends on the size of the sensitive volume. When the site size is 1 nm, biological cross sections are strongly correlated to combined probabilities of F2 and F3 calculated in the spherical volume, and the proportionality factor is the saturation value of biological cross sections. Full article
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Article
Charge Transfer and Electron Production in Proton Collisions with Uracil: A Classical and Semiclassical Study
Int. J. Mol. Sci. 2023, 24(3), 2172; https://doi.org/10.3390/ijms24032172 - 21 Jan 2023
Viewed by 512
Abstract
Cross sections for charge transfer and ionization in proton–uracil collisions are studied, for collision energies 0.05<E<2500 keV, using two computational models. At low energies, below 20 keV, the charge transfer total cross section is calculated employing a semiclassical close-coupling [...] Read more.
Cross sections for charge transfer and ionization in proton–uracil collisions are studied, for collision energies 0.05<E<2500 keV, using two computational models. At low energies, below 20 keV, the charge transfer total cross section is calculated employing a semiclassical close-coupling expansion in terms of the electronic functions of the supermolecule (H-uracil)+. At energies above 20 keV, a classical-trajectory Monte Carlo method is employed. The cross sections for charge transfer at low energies have not been previously reported and have high values of the order of 40 Å2, and, at the highest energies of the present calculation, they show good agreement with the previous results. The classical-trajectory Monte Carlo calculation provides a charge transfer and electron production cross section in reasonable agreement with the available experiments. The individual molecular orbital contributions to the total electron production and charge transfer cross sections are analyzed in terms of their energies; this permits the extension of the results to other molecular targets, provided the values of the corresponding orbital energies are known. Full article
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Article
Radical Production with Pulsed Beams: Understanding the Transition to FLASH
Int. J. Mol. Sci. 2022, 23(21), 13484; https://doi.org/10.3390/ijms232113484 - 03 Nov 2022
Cited by 2 | Viewed by 695
Abstract
Ultra-high dose rate (UHDR) irradiation regimes have the potential to spare normal tissue while keeping equivalent tumoricidal capacity than conventional dose rate radiotherapy (CONV-RT). This has been called the FLASH effect. In this work, we present a new simulation framework aiming to study [...] Read more.
Ultra-high dose rate (UHDR) irradiation regimes have the potential to spare normal tissue while keeping equivalent tumoricidal capacity than conventional dose rate radiotherapy (CONV-RT). This has been called the FLASH effect. In this work, we present a new simulation framework aiming to study the production of radical species in water and biological media under different irradiation patterns. The chemical stage (heterogeneous phase) is based on a nonlinear reaction-diffusion model, implemented in GPU. After the first 1 μs, no further radical diffusion is assumed, and radical evolution may be simulated over long periods of hundreds of seconds. Our approach was first validated against previous results in the literature and then employed to assess the influence of different temporal microstructures of dose deposition in the expected biological damage. The variation of the Normal Tissue Complication Probability (NTCP), assuming the model of Labarbe et al., where the integral of the peroxyl radical concentration over time (AUC-ROO) is taken as surrogate for biological damage, is presented for different intra-pulse dose rate and pulse frequency configurations, relevant in the clinical scenario. These simulations yield that overall, mean dose rate and the dose per pulse are the best predictors of biological effects at UHDR. Full article
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Article
Electron Attachment to 5-Fluorouracil: The Role of Hydrogen Fluoride in Dissociation Chemistry
Int. J. Mol. Sci. 2022, 23(15), 8325; https://doi.org/10.3390/ijms23158325 - 28 Jul 2022
Viewed by 657
Abstract
We investigate dissociative electron attachment to 5-fluorouracil (5-FU) employing a crossed electron-molecular beam experiment and quantum chemical calculations. Upon the formation of the 5-FU anion, 12 different fragmentation products are observed, the most probable dissociation channel being H loss. The parent anion, [...] Read more.
We investigate dissociative electron attachment to 5-fluorouracil (5-FU) employing a crossed electron-molecular beam experiment and quantum chemical calculations. Upon the formation of the 5-FU anion, 12 different fragmentation products are observed, the most probable dissociation channel being H loss. The parent anion, 5-FU, is not stable on the experimental timescale (~140 µs), most probably due to the low electron affinity of FU; simple HF loss and F formation are seen only with a rather weak abundance. The initial dynamics upon electron attachment seems to be governed by hydrogen atom pre-dissociation followed by either its full dissociation or roaming in the vicinity of the molecule, recombining eventually into the HF molecule. When the HF molecule is formed, the released energy might be used for various ring cleavage reactions. Our results show that higher yields of the fluorine anion are most probably prevented through both faster dissociation of an H atom and recombination of F with a proton to form HF. Resonance calculations indicate that F is formed upon shape as well as core-excited resonances. Full article
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Article
Simulating the Feasibility of Using Liquid Micro-Jets for Determining Electron–Liquid Scattering Cross-Sections
Int. J. Mol. Sci. 2022, 23(6), 3354; https://doi.org/10.3390/ijms23063354 - 20 Mar 2022
Cited by 3 | Viewed by 1549
Abstract
The extraction of electron–liquid phase cross-sections (surface and bulk) is proposed through the measurement of (differential) energy loss spectra for electrons scattered from a liquid micro-jet. The signature physical elements of the scattering processes on the energy loss spectra are highlighted using a [...] Read more.
The extraction of electron–liquid phase cross-sections (surface and bulk) is proposed through the measurement of (differential) energy loss spectra for electrons scattered from a liquid micro-jet. The signature physical elements of the scattering processes on the energy loss spectra are highlighted using a Monte Carlo simulation technique, originally developed for simulating electron transport in liquids. Machine learning techniques are applied to the simulated electron energy loss spectra, to invert the data and extract the cross-sections. The extraction of the elastic cross-section for neon was determined within 9% accuracy over the energy range 1–100 eV. The extension toward the simultaneous determination of elastic and ionisation cross-sections resulted in a decrease in accuracy, now to within 18% accuracy for elastic scattering and 1% for ionisation. Additional methods are explored to enhance the accuracy of the simultaneous extraction of liquid phase cross-sections. Full article
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