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Cerdanyola del Vallès, Spain

Nicolas J.,ALBA Synchrotron | Campos J.,Autonomous University of Barcelona
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

The use of linear methods to obtain both the error surface and the instrument error from redundant-independent datasets has been proposed to improve the accuracy of angle measuring scanning devices such as the long trace profilometer (LTP) or the nanometer optical measuring machine (NOM). In this work we propose to extend the method to measurements obtained during the calibration of mechanical benders. The proposed method allows determining an error-free measure of the slope error, the curvature and the cubic component of the mirror, as well as the instrument error. The description of the method, simulations and practical works are presented. © 2013 SPIE.

Owen R.L.,Diamond Light Source | Juanhuix J.,ALBA Synchrotron | Fuchs M.,Brookhaven National Laboratory
Archives of Biochemistry and Biophysics | Year: 2016

Following pioneering work 40 years ago, synchrotron beamlines dedicated to macromolecular crystallography (MX) have improved in almost every aspect as instrumentation has evolved. Beam sizes and crystal dimensions are now on the single micron scale while data can be collected from proteins with molecular weights over 10 MDa and from crystals with unit cell dimensions over 1000 Å. Furthermore it is possible to collect a complete data set in seconds, and obtain the resulting structure in minutes. The impact of MX synchrotron beamlines and their evolution is reflected in their scientific output, and MX is now the method of choice for a variety of aims from ligand binding to structure determination of membrane proteins, viruses and ribosomes, resulting in a much deeper understanding of the machinery of life. A main driving force of beamline evolution have been advances in almost every aspect of the instrumentation comprising a synchrotron beamline. In this review we aim to provide an overview of the current status of instrumentation at modern MX experiments. The most critical optical components are discussed, as are aspects of endstation design, sample delivery, visualisation and positioning, the sample environment, beam shaping, detectors and data acquisition and processing. © 2016 Published by Elsevier Inc.

Leon-Reina L.,University of Malaga | Garcia-Mate M.,University of Malaga | Garcia-Mate M.,X Ray Data Services S.L | Alvarez-Pinazo G.,University of Malaga | And 5 more authors.
Journal of Applied Crystallography | Year: 2016

This study reports 78 Rietveld quantitative phase analyses using Cu Kα1, Mo Kα1 and synchrotron radiations. Synchrotron powder diffraction has been used to validate the most challenging analyses. From the results for three series with increasing contents of an analyte (an inorganic crystalline phase, an organic crystalline phase and a glass), it is inferred that Rietveld analyses from high-energy Mo Kα1 radiation have slightly better accuracies than those obtained from Cu Kα1 radiation. This behaviour has been established from the results of the calibration graphics obtained through the spiking method and also from Kullback-Leibler distance statistic studies. This outcome is explained, in spite of the lower diffraction power for Mo radiation when compared to Cu radiation, as arising because of the larger volume tested with Mo and also because higher energy allows one to record patterns with fewer systematic errors. The limit of detection (LoD) and limit of quantification (LoQ) have also been established for the studied series. For similar recording times, the LoDs in Cu patterns, ∼0.2 wt%, are slightly lower than those derived from Mo patterns, ∼0.3 wt%. The LoQ for a well crystallized inorganic phase using laboratory powder diffraction was established to be close to 0.10 in stable fits with good precision. However, the accuracy of these analyses was poor with relative errors near to 100%. Only contents higher than 1.0 wt% yielded analyses with relative errors lower than 20%.

Padilla-Pantoja J.,Campus Universitari Of Bellaterra | Garcia-Munoz J.L.,Campus Universitari Of Bellaterra | Bozzo B.,Campus Universitari Of Bellaterra | Jirak Z.,ASCR Institute of Physics Prague | Herrero-Martin J.,ALBA Synchrotron
Inorganic Chemistry | Year: 2014

The Pr0.50Sr0.50CoO3 perovskite exhibits unique magnetostructural properties among the rest of the ferromagnetic/metallic Ln0.50Sr0.50CoO3 compounds. Existing reports are largely controversial. We have determined and described its structural evolution, which follows the Pm3¯m → R3¯c → Imma → I4/mcm transformations. The structural changes have been thoroughly described. The results are confronted with distinct nonconventional properties and spin-lattice coupling effects in another half-doped cobaltite based on praseodymium, Pr0.50Ca0.50CoO3. The Imma → I4/mcm symmetry change is responsible for the unexpected second magnetic transition. © 2014 American Chemical Society.

Garcia-Simon C.,University of Girona | Garcia-Borras M.,University of Girona | Gomez L.,University of Girona | Gomez L.,Autonomous University of Barcelona | And 8 more authors.
Nature Communications | Year: 2014

Since fullerenes are available in macroscopic quantities from fullerene soot, large efforts have been geared toward designing efficient strategies to obtain highly pure fullerenes, which can be subsequently applied in multiple research fields. Here we present a supramolecular nanocage synthesized by metal-directed self-assembly, which encapsulates fullerenes of different sizes. Direct experimental evidence is provided for the 1:1 encapsulation of C 60, C 70, C 76, C 78 and C 84, and solid state structures for the host-guest adducts with C 60 and C 70 have been obtained using X-ray synchrotron radiation. Furthermore, we design a washing-based strategy to exclusively extract pure C 60 from a solid sample of cage charged with a mixture of fullerenes. These results showcase an attractive methodology to selectively extract C 60 from fullerene mixtures, providing a platform to design tuned cages for selective extraction of higher fullerenes. The solid-phase fullerene encapsulation and liberation represent a twist in host-guest chemistry for molecular nanocage structures. © 2014 Macmillan Publishers Limited. All rights reserved.

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