Time filter

Source Type

Onesti S.,Elettra - Sincrotrone Trieste | MacNeill S.A.,University of St. Andrews
Chromosoma | Year: 2013

The CMG (Cdc45-MCM-GINS) complex is the eukaryotic replicative helicase, the enzyme that unwinds double-stranded DNA at replication forks. All three components of the CMG complex are essential for its function, but only in the case of MCM, the molecular motor that harnesses the energy of ATP hydrolysis to catalyse strand separation, is that function clear. Here, we review current knowledge of the three-dimensional structure of the CMG complex and its components and highlight recent advances in our understanding of its evolutionary origins. © 2013 Springer-Verlag Berlin Heidelberg. Source

Di Mitri S.,Elettra - Sincrotrone Trieste
Physical Review Special Topics - Accelerators and Beams | Year: 2013

Linear accelerators capable of delivering high brightness electron beams are essential components of a number of research tools, such as free electron lasers (FELs) and elementary particle colliders. In these facilities the charge density is high enough to drive undesirable collective effects (wakefields) that may increase the beam emittance relative to the injection level, eventually degrading the nominal brightness. We formulate a limit on the final electron beam brightness, imposed by the interplay of geometric transverse wakefield in accelerating structures and coherent synchrotron radiation in energy dispersive regions. Numerous experimental data of vacuum ultraviolet and x-ray FEL drivers validate our model. This is then used to show that a normalized brightness of ∼1016 A/m2, promised so far by ultralow charge beams (∼1-10 pC), can in fact be reached with a 100 pC charge beam in the 1.2 GeV FERMI@Elettra accelerator, with the existing machine configuration. Published by the American Physical Society Published by the American Physical Society under the terms of the http://creativecommons.org/licenses/by/3.0/Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Source

Jark W.,Elettra - Sincrotrone Trieste
Journal of Synchrotron Radiation | Year: 2013

Recently it was shown experimentally that regular arrays of tiny prisms can be used as X-ray monochromators providing a spectral bandwidth of below 2%. Successively the measured spectral transmission functions of monochromators operated under different conditions were found to be in agreement with expectations within an analytical model. This type of monochromator focuses chromatically and thus necessitates the use of an exit slit for the monochromatization. This contribution will show that the lower limit for the achievable bandpass can be predicted under practically feasible experimental conditions. Refractive monochromators based on prism arrays are found to be feasible solutions for monochromatization with high transmission to a spectral bandwidth of the order of 0.5%. The bandwidth can easily be increased by adjusting the exit slit setting accordingly. Consequently, the presented refractive devices would make for tunable monochromators with tunable bandwidth, which provides more flexibility for an intermediate bandwidth of <1%, which multilayer monochromators have difficulty providing routinely. © 2013 International Union of Crystallography Printed in Singapore-all rights reserved. Source

Locatelli A.,Elettra - Sincrotrone Trieste
Nature Nanotechnology | Year: 2016

Magnetic skyrmions are chiral spin structures with a whirling configuration. Their topological properties, nanometre size and the fact that they can be moved by small current densities have opened a new paradigm for the manipulation of magnetization at the nanoscale. Chiral skyrmion structures have so far been experimentally demonstrated only in bulk materials and in epitaxial ultrathin films, and under an external magnetic field or at low temperature. Here, we report on the observation of stable skyrmions in sputtered ultrathin Pt/Co/MgO nanostructures at room temperature and zero external magnetic field. We use high lateral resolution X-ray magnetic circular dichroism microscopy to image their chiral Néel internal structure, which we explain as due to the large strength of the Dzyaloshinskii–Moriya interaction as revealed by spin wave spectroscopy measurements. Our results are substantiated by micromagnetic simulations and numerical models, which allow the identification of the physical mechanisms governing the size and stability of the skyrmions. © 2016 Nature Publishing Group Source

Elettra - Sincrotrone Trieste and University of Bologna | Date: 2011-08-02

The present invention relates to organic semiconductors to be used as intrinsic, direct detectors for ionizing radiations, such as X and gamma rays, neutrons, and charged particles (alpha rays, electrons, positrons, and the like), and to a method for manufacturing such intrinsic, direct detectors for ionizing radiations. The invention further relates to instruments or complex devices provided with a detector based on, or somehow incorporating, the above detectors.

Discover hidden collaborations