Search results for "synchrotron"
showing 10 items of 307 documents
Quaternary structures of GroEL and naïve-Hsp60 chaperonins in solution: a combined SAXS-MD study
2015
The quaternary structures of bacterial GroEL and human naïve-Hsp60 chaperonins in physiological conditions have been investigated by an innovative approach based on a combination of synchrotron Small Angle X-ray Scattering (SAXS) in-solution experiments and molecular dynamics (MD) simulations. Low-resolution SAXS experiments over large and highly symmetric oligomers are analyzed on the basis of the high-resolution structure of the asymmetric protein monomers, provided by MD. The results reveal remarkable differences between the solution and the crystallographic structure of GroEL and between the solution structures of GroEL and of its human homologue Hsp60.
Unraveling the Formation of Core−Shell Structures in Nanoparticles by S-XPS
2010
The combination of the surface sensitivity of X-ray photoelectron spectroscopy (XPS) with the high flux and variable photon energy excitation of Synchrotron radiation (S-XPS) is used to probe the atomic distribution of bimetallic nanoparticles. Based on the energy dependence of the photoemission differential cross section of core level photoelectrons, we propose a methodology to monitor the formation and to evaluate sizes of the core−shell structure. We have successfully applied it to unveil the mechanism involved in the atomic rearrangement of thermally treated Pt0.7Pd0.3 nanoparticles.
Enhancing the sensitivity of nano-FTIR spectroscopy.
2017
Synchrotron radiation-based nano-FTIR spectroscopy utilizes the highly brilliant and ultra-broadband infrared (IR) radiation provided by electron storage rings for the infrared spectroscopic characterization of samples at the nanoscale. In order to exploit the full potential of this approach we investigated the influence of the properties of the radiation source, such as the electron bunch shape and spectral bandwidth of the emitted radiation, on near-field infrared spectra of silicon-carbide (SiC). The adapted configuration of the storage ring optics enables a modification of the transverse electron bunch profile allowing an increase of the measured near-field signal amplitude. Additionall…
Infrared microspectroscopy of biochemical response of living cells in microfabricated devices
2010
Abstract First experiments demonstrating the suitability of novel microfabricated fluidic devices for measuring living cells in physiological environment by synchrotron radiation (SR) Fourier Transform Infrared microspectroscopy (μ-FTIR) are presented. The devices were fabricated on CaF 2 windows, using the photoresist XARP 3100/10 to define the liquid cell lay-out. Therefore, the sample holder is transparent to both visible and infrared light, robust, completely recyclable and with a precise spacing. Using prototype devices of thicknesses 9, 5 and 3 μm, we studied the response of the U937 monocytic cell line to mechanical compression. The temporal evolution of the FTIR spectra, characteris…
Time-resolved photoemission electron microscopy
2009
The excellent time structure of Synchrotron radiation and short-pulse lasers has opened the door to a novel way of time-resolved imaging using PEEM. Periodic or repetitive processes can be studied by stroboscopic illumination with the pulsed photon beam. Since the first experiments in 2003, two fields of applications have been established in several groups. One concerns the investigation of fast magnetisation processes like precessional switching, Gigahertz-eigenmodes of ferromagnetic nanostructures or travelling spin waves in thin films. More recently, femtosecond lasers have been used for imaging of localised surface plasmons in nanoparticles and their temporal behaviour in the femtosecon…
Charge Transport Properties in CZT Detectors Grown by the Vertical Bridgman Technique
2010
Great efforts are being presently devoted to the development of CdTe and CdZnTe detectors for a large variety of applications, such as medical, industrial, and space research. We present the spectroscopic properties of some CZT crystals grown by the standard vertical Bridgman method and by the boron oxide encapsulated vertical Bridgman method, which has been recently implemented at IMEM-CNR (Parma, Italy). By this technique the crystal is grown in an open quartz crucible fully encapsulated by a thin layer of liquid boron oxide. This method prevents contact between the crystal and the crucible thereby allowing larger single grains with a lower dislocation density to be obtained. Several mono…
Progress in development of a new luminescence setup at the FinEstBeAMS beamline of the MAX IV laboratory
2019
The main funding for the FinEstBeAMS beamline has been obtained from the European Union through the European Regional Development Fund (project “Estonian beamline to MAX-IV synchrotron”, granted to the University of Tartu) and from the Academy of Finland through the Finnish Research Infrastructure funding projects ( FIRI2010 , FIRI2013 , FIRI2014 ). The authors also acknowledge the funding contributions of the University of Oulu , University of Turku , Tampere University of Technology , the Estonian Research Council ( IUT 2-25 , IUT 2-26 , PRG-111 ), as well as the Estonian Centre of Excellence in Research “Advanced materials and high-technology devices for sustainable energetics, sensorics…
CERN-MEDICIS: A Review Since Commissioning in 2017
2021
The CERN-MEDICIS (MEDical Isotopes Collected from ISolde) facility has delivered its first radioactive ion beam at CERN (Switzerland) in December 2017 to support the research and development in nuclear medicine using non-conventional radionuclides. Since then, fourteen institutes, including CERN, have joined the collaboration to drive the scientific program of this unique installation and evaluate the needs of the community to improve the research in imaging, diagnostics, radiation therapy and personalized medicine. The facility has been built as an extension of the ISOLDE (Isotope Separator On Line DEvice) facility at CERN. Handling of open radioisotope sources is made possible thanks to i…
Dust Production and Particle Acceleration in Supernova 1987A Revealed with ALMA
2013
Supernova (SN) explosions are crucial engines driving the evolution of galaxies by shock heating gas, increasing the metallicity, creating dust, and accelerating energetic particles. In 2012 we used the Atacama Large Millimeter/Submillimeter Array to observe SN 1987A, one of the best-observed supernovae since the invention of the telescope. We present spatially resolved images at 450um, 870um, 1.4mm, and 2.8mm, an important transition wavelength range. Longer wavelength emission is dominated by synchrotron radiation from shock-accelerated particles, shorter wavelengths by emission from the largest mass of dust measured in a supernova remnant (>0.2Msun). For the first time we show unambig…
Desktop X-ray tomography for low contrast samples
2013
Abstract Based on the experience in the use of polycapillary optical systems, recently XLab Frascati LNF and IM CNR have been strongly involved in studying the techniques for high resolution X-ray Imaging and micro-tomography that intends in the development of a new imaging instrument to examine low contrast samples complicated by fast developing processes. In order to get the reliable signal to noise ratio, typically available via synchrotron radiation (SR) dedicated X-ray optical devices, for the desktop solutions we have to increase the radiation fluxes from conventional sources. As known, manipulated through polycapillary optics beams result in getting higher fluxes with respect to a pi…