Highlights
Protein dynamics under realistic conditions
| In a study published in J. Phys. Chem. Lett. a collaboration from Tübingen, Grenoble, Dublin and Lund shows the influence of the high proportion of macromolecular components ("crowding") on the diffusion of proteins. Using a model system that simulates the situation in a living cell, the dependence of diffusion on the polydispersity of the macromolecular components in particular can be better understood. The key to this understanding lies in the combination of high-resolution neutron spectroscopy ("quasi-elastic neutron scattering" in backscattering geometry) and complex computer simulations. M. Grimaldo et al., J. Phys. Chem. Lett. 10 (2019), 1709, https://dx.doi.org/10.1021/acs.jpclett.9b00345 M. Grimaldo et al., Quart. Rev. Biophys. 52 (2019), e7, 1, https://dx.doi.org/10.1017/S0033583519000027 |
Bio imaging with scanning small angle neutron scattering
| In a recent study published in Scientific Reports, researchers from FZ Jülich and RWTH Aachen show that the orientation and distribution of nerve fibers as well as myelin in thin brain sections can be determined using scanning small angle neutron scattering (sSANS). The method is very sensitive to small microstructures of biological tissue and can directly extract information on the average fiber orientation and even myelin membrane thickness. The present results pave the way toward bio-imaging for detecting structural aberrations causing neurological diseases in future. [S. Maiti, et al., Sci Rep 11, 17306 (2021)] |
Gallium arsenide for high resolution in neutron backscattering spectroscopy
|
The usage of gallium arsenide instead of silicon crystals is a great step forward in neutron backscattering spectroscopy. The theoretical energy resolution limit for an ideal GaAs(200) crystal is just 13 neV, since it scatters neutrons much less than silicon. It’s been known since the 1990s that the reflection off the (200) surface of galliumarsenide could potentially do better, but only now the GaAs fabrication is sufficiently advanced for a large-area perfectly crystalline analyzer to be feasible. Many paramters have to be taken into account and optimized in the application as analyser. Berhard Frick, Andreas Magerl and their colleagues have tackled the issue and done first proof-of-concept measurements at a prototype at IN16B, ILL. They arready reach a resolution of 78 neV - the lowest one for silicon lies at 300 neV. Johanna L. Miller reports on the project and its potential for neutron backscattering spectroscopy in Physics Today (72). (original publication: K. Kuhlmann, M. Appel, B. Frick, and A. Magerl, Rev Sci Instrum 90, 015119 (2019)) The project was funded by the joint research program of the BMBF. [more] |