Scientific Highlights
Itinerant and Localized Magnetization Dynamics in Antiferromagnetic Holmium
Resonant magnetic scattering performed at the x-ray free electron laser facility LCLS (USA) has been used to investigate the magnetization dynamics of elemental Holmium. It is found that the demagnetization of conduction electrons and localized 4f magnetic moments have the same temporal evolution showing a strong coupling between the different magnetic moments.
First light from the SwissFEL Experimental Laser
The SwissFEL Experimental Laser 1 has successfully been delivered and installed in a temporary laser lab by Coherent, from where it will be moved to SwissFEL by end of 2016. The pre-installation in the temporary laser lab allows to become acquainted with the system, to set up a full monitoring and diagnostics system and to debug potential problems in the next months.
Investigating DNA Radiation Damage Using X-Ray Absorption Spectroscopy
The key to achieving more effective radioprotection and radiotherapy is to understand the exact mechanism of the interaction between radiation and biomolecules, and in particular to obtain the precise structure of the different forms of damage and their relative ratios. Among all biomolecules exposed to radiation, DNA plays an important role because any damage to its molecular structure can affect the whole cell and may lead to chromosomal rearrangements resulting in genomic instability or cell death.
Organic Nitrate Contribution to New Particle Formation and Growth in Secondary Organic Aerosols from α-Pinene Ozonolysis
The chemical kinetics of organic nitrate production during new particle formation and growth of secondary organic aerosols (SOA) were investigated using the short-lived radioactive tracer 13N in flow-reactor studies of α-pinene oxidation with ozone. Direct and quantitative measurements of the nitrogen content indicate that organic nitrates accounted for ∼40% of SOA mass during initial particle formation, decreasing to ∼15% upon particle growth to the accumulation-mode size range (>100 nm). Experiments with OH scavengers and kinetic model results suggest that organic peroxy radicals formed by α-pinene reacting with secondary OH from ozonolysis are key intermediates in the organic nitrate formation process
Centriolar CPAP/SAS-4 Imparts Slow Processive Microtubule Growth
Centrioles are fundamental and evolutionarily conserved microtubule-based organelles whose assembly is characterized by microtubule growth rates that are orders of magnitude slower than those of cytoplasmic microtubules. Here, we bring together crystallographic, biophysical, and reconstitution assays to demonstrate that the human centriolar protein CPAP (SAS-4 in worms and flies) binds and "caps" microtubule plus ends by associating with a site of β-tubulin engaged in longitudinal tubulin-tubulin interactions.
Dimensional Reduction in Quantum Dipolar Antiferromagnets
We report ac susceptibility, specific heat, and neutron scattering measurements on a dipolar-coupled antiferromagnet LiYbF4. For the thermal transition, the order-parameter critical exponent is found to be 0.20(1) and the specific-heat critical exponent −0.25(1). The exponents agree with the 2D XY/h4 universality class despite the lack of apparent two-dimensionality in the structure.
The role of ions in the self-healing behavior of soft particle suspensions
A. Scotti et al., Proceedings of the National Academy of Sciences, 1516011113 (2016). Understanding when a material crystallizes is of fundamental importance in condensed matter. In many materials, the presence of point defects suppresses crystallization. Surprisingly, colloidal hydrogels can overcome this limitation: A small number of large microgels can spontaneously deswell to fit in the crystal lattice of smaller microgels, thus avoiding the occurrence of point defects.
How does food look like on the nanoscale?
The answer to this question could save food industry a lot of money and reduce food waste caused by faulty production. Researchers from the University of Copenhagen and the Paul Scherrer Institut have obtained a 3D image of food on the nanoscale using ptychographic X-ray computed tomography. This work paves the way towards a more detailed knowledge of the structure of complex food systems.
Robust Magnetic Properties of a Sublimable Single Molecule Magnet
The organization of single-molecule magnets (SMMs) on surfaces via thermal sublimation is a prerequisite for the development of future devices for spintronics exploiting the richness of properties offered by these magnetic molecules. However, a change in the SMM properties due to the interaction with specific surfaces is usually observed.
The role of ions in the self-healing behavior of soft particle suspensions
Understanding when a material crystallizes is of fundamental importance in condensed matter. In many materials, the presence of point defects suppresses crystallization. Surprisingly, colloidal hydrogels can overcome this limitation: A small number of large microgels can spontaneously deswell to fit in the crystal lattice of smaller microgels, thus avoiding the occurrence of point defects.