FIAS Scientific Report 2010 - Frankfurt Institute for Advanced Studies ...

connectivity using electrophysiological data based on simulations and magnetoencephalography (MEG)
recordings in a simple motor task.
The role of cortical gamma oscillations has been studied by T. Burwick who concentrated on finding their
possible functional relevance by using appropriate dynamical system models of the oscillatory processes.
Based on recent experimental work it was shown that the oscillatory state may realize a form of selective inhibition
– resulting in the recognition processes – that could not be achieved without including the temporal
structure as it arises with the gamma oscillations.
In collaboration with the Department of Developmental Psychology at Goethe University the group of J.
Triesch has developed a new method to study the cognitive abilities of infants. An eye-tracker is used to
analyze the direction of gaze of the infant and the outcome is used to influence the scenes shown on a
computer display. In this way 6-month old children obtain the ability to manipulate their environment and
learn to anticipate the outcomes of their actions. This opens the possibility to address a wide variety of
classic questions including habituation, joint attention, and object conception in a new way.
Meso-Bio-Nano-Science
The MBN group at FIAS (A. Solov’yov) studies the structure and properties of a variety of objects on
the nanoscale. This includes atomic and molecular clusters, nanoparticles, nanowires, micro-droplets, and
biomolecules.
Recently the group has increasingly focused its attention on the molecular-level assessment of radiation biodamage,
in particular in connection with the method of heavy-ion tumour therapy. In 2010 the MBN group
initiated the European COST Action ‘Nano-scale insights into ion beam cancer therapy’. A. Solov’yov was
elected to chair the Management Committee of the Action.
The MBN group has suggested a multi-scale approach to the scenario of irradiation of biological targets
with ions aiming to understand the physics of radiation biodamage. This was used to calculate probability
of DNA damage as a result of the irradiation with energetic ions, up to several hundreds of MeV/u. The
approach covers different time and spatial scales, defined by different physical processes such as the ion
stopping, the propagation of secondary electrons and radicals, the interactions of secondaries with the DNA
and proteins, thermo-mechanical effects etc. The probabilities of single and double strand breaks were
calculated.
In 2010 important advances of the molecular level assessments of radiation damage were made. The energy
distributions of secondary electrons produced by energetic carbon ions incident on liquid water in the energy
range used in hadron therapy were calculated and parametrizations for the differential cross sections of
ionization were developed. Calculations of the complex DNA damage and the effects of thermal spikes on
biomolecules in the context of the multiscale approach were worked out, allowing to quantify the occurrence
of complex clustered damage to DNA. Furthermore, the shock wave produced by an energetic ion in liquid
water was investigated. The pressure in the overheated water increases by several orders of magnitude and
drives a cylindrical shock wave on the nanometer scale, possibly providing an important mechanism for
causing DNA damage.
Another achievement of the MBN group ist the development of a radiation source based on the principle of a
crystalline undulator. The newest scheme for a hard-X-ray and gamma laser is based on the combination of
a conventional undulator with an undulator utilizing a periodically bent crystal. A patent for the new source
of coherent radiation has been submitted.
Biology
The systems immunology group at FIAS (M. Figge, M. Meyer-Hermann, now at Braunschweig) in 2010
has reached a major new insight concerning the relation between adaptive and innate immunity.
In germinal centers where the affinity maturation of antibodies takes place, antigen-activated B cells undergo
proliferation, somatic hypermutation, and selection with regard to the antibody affinity. Follicular dendritic
cells (FDCs) are key players in driving these events of adaptive immunity via direct interaction with germinal
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