Yearbook 2011

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Sr3[Co(CN)3] and Ba3[Co(CN)3]: "Simple" compounds with extensive consequences on the chemistry of highly reduced metalates

Max Planck Institute for Chemical Physics of Solids Höhn, Peter; Jach, Franziska; Karabiyik, Boris; Agrestini, Stefano; Wagner, Frank-R.; Ruck, Michael; Tjeng, Liu Hao; Kniep, Rüdiger
The CN ligands in the isotypic compounds Sr3[Co(CN)3] und Ba3[Co(CN)3] have lost their "innocence" by higher reduction and weakening of the C–N bond, for the first time. For cobalt a closed-shell (d10)-configuration was determined. The resulting mesomeric structures of the trigonal-planar complex anions, [Co1–(CN)2(CN)3–]6–, open new insight into the chemistry of metalates and coordination compounds of transition metals with CN ligands. Finally, consequences on the chemistry of carbonylmetalates can be expected, too. more

Zero resistance by magnetism

Max Planck Institute for Chemical Physics of Solids Stockert, Oliver; Arndt, Julia; Jeevan, Hirale S.; Geibel, Christoph; Steglich, Frank
The question about the origin of unconventional superconductivity is one of the central issues in current condensed matter physics. Within an international collaboration scientists from the Max Planck Institute for Chemical Physics of Solids discovered that magnetic interactions are responsible for the Cooper pair formation and hence for the lossless current transport. While in conventional superconductors magnetism is detrimental for superconductivity, magnetism is an essential prerequisite for superconductivity in materials displaying unconventional superconductivity. more
The MPE successfully performs research on complex plasmas on the International Space Station ISS since ten years. This allows scientifically new insights in many fields of physics. More than 60 publications in refereed journals have appeared. Some results shall be presented here. This research not only has a successful history but also a promising future: the next lab PK-4 shall be launched in 2014 and for the farer future a new lab is under development. Thus, plasma crystal research might cover the whole span of life of the ISS. more
eROSITA is the core instrument on the Russian Spectrum-Roentgen-Gamma mission. From 2013 on eROSITA is expected to deeply survey the entire X-ray sky. The driving science is the detection of 100.000 distant galaxy clusters in order to study the large scale structure in the Universe and test cosmological models including Dark Energy. In addition, eROSITA will detect about 3 million Active Galaxies, widening our view on the evolution of supermassive black holes. eROSITA will also provide new clues on other astrophysical topics, like X-ray binaries and the diffuse galactic emission. more
In spite of the convincing evidence for Dark Matter, up to now its nature couldn’t be clarified. Experiments for the direct detection of Dark Matter are concentrating mainly on the search for WIMPs (Weakly Interacting Massive Particles) which are presently the most favoured candidates for the composition of Dark Matter. The CRESST-Experiment is among these experiments using a novel, specially developed detector type. The first measurement period of the CRESST-Experiment lasted until mid of 2011. The results may be a first hint for the existence of light mass WIMPs. more

Semiconductor nanowires: versatile building blocks in various novel optical applications

Max Planck Institute for the Science of Light Bashouti, Muhammad; Brönstrup, Gerald; Christiansen Silke H.; Hoffmann, Björn; Kiometzis, Michael; Pietsch, Matthias; Sarau, George; Schmitt, Sebastian; Sivakov, Vladimir; Tessarek, Christian; Voigt, Felix
The investigation of optical properties of semiconductor nanowires and their controlled modification has a wide range of potential applications in areas from sensing to photovoltaics. At the Max Planck Institute for the Science of Light a wide variety of methods is used to advance this type of research. A noteworthy achievement is a working Silicon-nanowire based solar cell with efficiencies >9%. This result underlines the promising potential of semiconductor nanowires in efficient thin film photovoltaics. more

New territories for fibre optics: short wavelengths and high intensities

Max Planck Institute for the Science of Light Hölzer, Philipp; Nold, Johannes; Travers, John C.; Russell, Philip St. J.
Microstructured photonic crystal fibre has introduced the unique new opportunity to guide light over long distances in a hollow core. This allows one to carry out detailed studies of nonlinear light-gas interactions under extreme conditions. Two recent results are reported: the generation of bright tunable deep-ultraviolet light and pulse propagation in photo-ionised noble gases. more
The access to internet data allows for unprecedented quantitative investigations of human activities.  An investigation of the communication between thousands of users across more than a decade will be reported here. The statistical analysis of word frequencies provides insights on the interests of the users and also on how language is used and changes. more
In the last few years, observations at highest energies have provided important fundamental insight into astrophysical processes in cosmic objects. They represent key steps towards the understanding of these objects. Two selected highlights of gamma-ray astromony are presented. more

Laser acceleration of ions

Max Planck Institute for Nuclear Physics Harman, Zoltán; Galow, Benjamin J.; Keitel, Christoph H.
Theoretical studies show that high-intensity laser pulses can accelerate ions to high velocities. The energies reached and the energy uncertainty, quality and intensity of the ion beams generated this way may be useful for several applications, including e. g. ion beam cancer therapy. Model calculations also imply that the beam properties required may be achieved with a frequency modulation of the laser pulse. This method of laser acceleration may constitute in future a more economic alternative to conventional particle accelerator systems. more
Transport processes in human cells are essential for various cellular activities, e.g. the destruction of disease agents. Therefore, a class of switch proteins direct the temporal and spatial coordination of intracellular transportation. Some pathogens (e.g. the causative agent of Legionnaires’ disease) have contrived ways and means to manipulate these processes. The investigation of the molecular basis of such manipulations enables researchers to develop a deeper understanding of the biochemistry of diseases but also of the principles of intracellular transport processes. more
After DNA replication, chromosomes consist of two identical copies of the genetic material “glued” together. During mitosis, or M-phase, the “glued” chromosomes (sister chromatids) align on a scaffold known as the mitotic spindle. Upon completion of alignment, the sister chromatids become separated and distributed to opposite ends of the dividing mother cell. This way, each daughter cell inherits an equal complement of chromosomes. Problems in the execution of mitosis lead to unbalances in chromosome numbers (aneuploidy), a common genetic abnormality in tumors. more
Plants display remarkable robustness against attempted pathogen infection and in their natural environment disease is the exception. Analysis of Arabidopsis plants is illuminating some fundamental processes by which plants recognize and resist microbial pathogen invasion. What emerges from recent studies is a set of distinct immune response branches in different parts of the host cell which are strictly coordinated to produce effective immunity. more
Many traits that play important roles in plant breeding are complex, meaning that they are controlled by multiple genetic and environmental factors. Knowledge of the corresponding genes facilitates early diagnoses of complex traits and thereby increases the efficiency and precision of breeding new varieties of crop plants. To identify such genes, association-studies for complex traits of potato were conducted at the institute. Highly significant associations were identified between candidate genes and complex traits such as resistance to potato late blight disease. more
Plants do not only produce oxygen, they also use it as a substrate for respiratory energy production. However, the oxygen concentration within plant tissues can drop to very low levels (hypoxia), because plants lack any active distribution system for oxygen. During recent years, much new knowledge has become available about how plant metabolism adapts to the regularly occurring hypoxic conditions within a plant and how oxygen concentrations in plants are being sensed. more
The Max Planck Institute for Plasma Physics in Garching makes with the worldwide largest ion source test facility for negative hydrogen ions ELISE a major contribution for the success of the international fusion experiment ITER in Cadarache. After two years of construction ELISE will start operation in June 2012. The aim is to demonstrate the source parameters required for the heating and long pulse operation of the fusion plasma. The ion source is aimed to deliver a one hour negative deuterium ion beam of 20 A from a source with half the size of that for the ITER source. more
The ultra-hot fusion plasma with extremely low density is confined in the fusion devices by magnetic forces without making contact with the vessel wall. The divertor is the only place in the plasma vessel that is touched by the plasma. For the Wendelstein 7-X research device, now being built at Greifswald, divertor components were developed that can permanently withstand the extremely high heat loads of 10 MW/ m2. more
By using a modular approach the miniemulsion process allows for the formation of complex functionalized polymer nanoparticles and the encapsulation of solid or liquid, inorganic or organic, hydrophobic or hydrophilic materials in a polymer shell. Here, different materials from organic and inorganic pigments, magnetite or other solid materials to hydrophilic or hydrophobic liquids like perfumes, vitamins, drugs, or photoinitiators can be encapsulated and deliberated in a well-defined manner. The functionalization of the nanoparticles can be easily controlled. more
It has been a long-standing dream to watch molecules as they rotate, translate, interact and react to form new chemicals with temporal and spatial resolution that matches the molecular scale, i.e. on femtosecond time scales and nanometer length scales. Several new laser-based vibrational spectroscopic approaches are presented here, aimed towards the realization of this dream, with a specific emphasis of watching molecules at work on surface and interfaces. more
An impaired stress-hormone regulation plays an important role for the development of depression. Genetic variations in the FKBP5 gene expressing a modulator of the stress hormone axis contribute in interaction with environmental stress factors to increased depression susceptibility. Successful antidepressant treatment is closely related to the recovery of the stress hormone regulation, which in turn is modulated by FKBP5 activity. Thus, FKBP5 is a promising target for future antidepressant drugs, which should be particularly effective in patients with impaired stress-hormone regulation. more
Mutations in the FOXP2 gene cause severe speech and language disorder. FOXP2 encodes a protein that regulates the switching on and off of other genes. It is not yet clear why mutations of FOXP2 mainly impact on language, and the neural mechanisms that it directs remain largely unknown. Scientists at the MPI for Psycholinguistics performed large-scale screens of genetic pathways downstream of this regulatory protein in developing brain, and uncovered a role in modulating connectivity of neurons. These data suggest that FOXP2 may help in wiring up neural circuits important for language. more
It has long been recognized that world knowledge influences how we view the world around us. It was not clear, however, whether this influence was exerted by the exact perceptual memory of how things looked or rather by abstract, factual knowledge about objects in the world. While these two sources of knowledge are usually highly correlated, traffic lights constitute an exception by being physically similar in European countries but named differently. Using this test bed, it was possible to show that language-specific labels guide how we see the things around us. more
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