FIAS Scientific Report 2011 - Frankfurt Institute for Advanced Studies ...

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Mechanism of double strand breaking in DNA Collaborators: E. Surdutovich 1 , A.V. Solov’yov 2 , A.V. Yakubovich 2 , W. Greiner 2 1 Oakland University, Michigan, USA, 2 Frankfurt Institute for Advanced Studies Short description: A mechanism of double strand breaking (DSB) in DNA due to the action of two electrons is considered. These are the electrons produced in the vicinity of DNA molecules due to ionization of water molecules with a consecutive emission of two electrons, making such a mechanism possible. This effect qualitatively solves a puzzle of large yields of DSBs following irradiation of DNA molecules. Main results: It is widely accepted that single strand breaks (SSBs) in DNA are due to direct action of low energy electrons. This, however, does not explain the mechanism of DSBs, since a single electron can only attach to one site causing dissociation. The number density of secondary electrons, produced on the ion’s path, reduces rather steeply with the increasing distance from the path, so that the probability of two electrons incident on a single convolution of a DNA molecule, located a few nm from the track is very small. However, when ionization of a water molecule (cluster) producing an Auger electron occurs at a distance from the track, three electrons emerging from the same spot substantially boost the local number density of electrons and, hence, the probability of a nearby DNA convolution to be hit with two electrons. Thus, due to the Auger mechanism, events in which two or more electrons interact with a single DNA convolution are not rare. DSB or other types of complex damage may result from these interactions. The dependence of probability of two electrons to hit the same DNA convolution on the distance of the convolution from the origin is shown in Fig. 1, where it is compared to the probability to be hit by the original secondary electron. It is remarkable, that for r < 2nm the probability of the impact of two electrons is comparable to that of one. A substantial quantity of this fluence makes the Auger-mechanism influence on DSB yield viable. The contribution of Auger electrons to the fluence of secondary electrons was calculated. The additional fluence is compared to that of electron coming from the ion’s path in Fig. 2. The calculation of the fluence of Auger electrons gives a framework for the calculation of the transport of free radicals formed due to an ion’s traverse through a medium. This calculation, without the use of Monte Carlo simulations has long been desired. Probability 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 0 1 2 3 4 r�nm� The probability for two electrons to pass through a single convolution of DNA (solid line) compared to that of one electron (dashed line). Related publications in 2011: The dependence of the fluence of an Auger electron from ionization by a secondary electron on the distance from the ion’s path (solid line) compared to that of a single electron emitted from the path (dashed line). 1. E. Surdutovich and A.V. Solov’yov, Double strand breaks in dna resulting from double-electron-emission events, Phys. Rev. Lett. submitted for publication in 2011. 102
Novel light sources: Crystalline undulator and crystalline-undulator–based gamma-laser Collaborators: A. Kostyuk 1 , A.V. Korol 1 , A.V. Solov’yov 1 , W. Greiner 1 , H. Backe 2 , W. Lauth 2 , U. Uggerhoj 3 , V. Guidi 4 1 Frankfurt Institute for Advanced Studies, 2 Johannes Gutenberg-Universität Mainz, Germany 3 Aarhus University, Den- mark, 4 Ferrara University, Italy Short description: Investigation of the feasibility of constructing a new powerful source of high-energy (¯hω ∼ 0.1 − 1 MeV) monochromatic electromagnetic FEL-like radiation by a bunch of ultra-relativistic particles channelling through a periodically bent crystal (crystalline undulator, CU). Potential applications include plasma, nuclear and solid state physics, molecular biology, medicine and technology. Main results: • A patent for a hard x- and gamma-ray laser has been published [1]. It combines a CU with a conventional undulator. A beam of ultrarelativistic charged particles becomes spatially modulated in the conventional undulator so that it contains a harmonic with a period equal to the wavelength of the radiation of the CU. Due to this harmonic, the radiation process in the CU becomes coherent. • A simulation of 855 MeV electron channeling of in Silicon has been performed with a new computer code. The dechanneling lengths for (100), (110) and (111) crystallographic planes have been estimated. The dependence of the intensity of the channeling radiation (ChR) on the crystal dimension along the beam has been calculated. A good agreement with recent experimental data is observed [2]. • The behaviour of a modulated positron beam in a planar crystal channel is investigated. The evolution of the particle distribution is described by means of the Fokker-Planck equation. A detailed analysis of the equation has been performed. It is demonstrated that the beam preserves its modulation at sufficiently large penetration depths which allows using a crystalline undulator as a coherent source of hard x- and γ-rays. This result is of crucial importance for the theory of the CU based γ-laser [3]. Nph (0.4 MeV
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FIAS Scientific Report 2011
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FIAS Scientific Report 2011 Table o
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Physics Research highlights 2011 To
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1. Partner Research Centers 9
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ExtreMe Matter Institute EMMI by Ca
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Bernstein Focus Neurotechnology Fra
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2. Graduate Schools 15
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participants reported on their proj
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Courses offered at FIGSS Summer Sem
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3. FIAS Scientific Life 21
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28.07.2011 Prof. Dr. Victor Flambau
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Conferences and meetings (co)organi
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4. Research Reports 4.1 Nuclear Phy
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Hydrodynamics of a quark droplet Co
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Production of hyper-nuclei in react
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On production and properties of mul
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Monte Carlo modeling microdosimetry
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Monte Carlo simulation of the spall
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Dimuon radiation within a (3+1)d hy
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Initial state anisotropies and thei
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Chiral hadronic model including res
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Trace anomaly and the vector coupli
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Dileptons from the strongly interac
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Space-time evolution of the magneti
Page 51 and 52: Extreme isospin in heavy nuclei Col
Page 53 and 54: Production of heavy and superheavy
Page 55 and 56: The phase diagram in T -µB-Nc spac
Page 57 and 58: Critical Zeeman Fields for Unitary
Page 59 and 60: BCS-BEC Crossover in 2D Fermi Gases
Page 61 and 62: Applications of a chiral SU(3) mode
Page 63 and 64: The phase diagram of black holes in
Page 65 and 66: Black holes in short scale modified
Page 67 and 68: Fractal dimensions and micro-struct
Page 69 and 70: Untangling the interactions between
Page 71 and 72: Stimulus information coded by spike
Page 73 and 74: Non-stationarity of neuronal activi
Page 75 and 76: Timescale of information processing
Page 77 and 78: Discovery of agency in 6 and 8-mont
Page 79 and 80: Power spectra of the natural input
Page 81 and 82: Self-organization in recurrent neur
Page 83 and 84: Learning mechanisms underlying visu
Page 85 and 86: Emerging Bayesian priors in a self-
Page 87 and 88: Non-linear generative models and th
Page 89 and 90: Preference elicitation and Bayesian
Page 91 and 92: 4.3 Biology, Chemistry, Molecules,
Page 93 and 94: DNA unzipping Collaborators: S.N. V
Page 95 and 96: Statistical mechanics of protein fo
Page 97 and 98: Phase transitions in large clusters
Page 99 and 100: Photo-processes in fullerenes and e
Page 101: Assessment of complex DNA damage Co
Page 105 and 106: Monte-Carlo code for channeling dyn
Page 107 and 108: Programs for many-body descriptions
Page 109 and 110: Are 12 C radiation effects in liver
Page 111 and 112: Objective identification of residue
Page 113 and 114: Structural basis for the dual RNA-r
Page 115 and 116: The ALICE High Level Trigger Collab
Page 117 and 118: Arithmetic over Galois fields on mo
Page 119 and 120: High Performance GPU-based DGEMM an
Page 121 and 122: How stable are transport model resu
Page 123 and 124: 5. Talks and Publications 123
Page 125 and 126: Conference and Seminar Talks 2011
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Page 133 and 134: FIAS conference abstracts and poste
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FIAS publications 2011 - Patents 24
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The success of FIAS would not have
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