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Benedetti G.,ALBA Synchrotron Light Facility
IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference | Year: 2013

The potential hazards introduced by injecting into the ALBA storage ring with front end shutters open are determined through particle tracking simulations. The method is based on the possible overlap between phase space of forwards and backwards tracking between the straight section downstream the front end and the beamline. Realistic magnetic field, trajectory, aperture and energy errors are taken into account. Scenarios that could bring an injected beam of electrons passing through an open beamline front end are identified. The interlocks required to prevent such situations from arising are discussed. Copyright © 2013 by JACoW- cc Creative Commons Attribution 3.0 (CC-BY-3.0). Source


Larocca T.J.,State University of New York at Stony Brook | Crowley J.T.,State University of New York at Stony Brook | Cusack B.J.,State University of New York at Stony Brook | Pathak P.,State University of New York at Stony Brook | And 4 more authors.
Cell Host and Microbe | Year: 2010

Borrelia burgdorferi, the agent of Lyme disease, is unusual as it contains free cholesterol and cholesterol glycolipids. It is also susceptible to complement-independent bactericidal antibodies, such as CB2, a monoclonal IgG1 against outer surface protein B (OspB). We find that the bactericidal action of CB2 requires the presence of cholesterol glycolipids and cholesterol. Ultrastructural, biochemical, and biophysical analysis revealed that the bacterial cholesterol glycolipids exist as lipid raft-like microdomains in the outer membrane of cultured and mouse-derived B. burgdorferi and in model membranes from B. burgdorferi lipids. The order and size of the microdomains are temperature sensitive and correlate with the bactericidal activity of CB2. This study demonstrates the existence of cholesterol-containing lipid raft-like microdomains in a prokaryote, and we suggest that the temperature dependence of B. burgdorferi lipid raft organization may have significant implications in the transmission cycle of the spirochetes which are exposed to a range of temperatures. © 2010 Elsevier Inc. Source


Bazaga-Garcia M.,University of Malaga | Colodrero R.M.P.,University of Malaga | Papadaki M.,University of Crete | Garczarek P.,Wroclaw University of Technology | And 9 more authors.
Journal of the American Chemical Society | Year: 2014

We report the synthesis, structural characterization, and functionality (framework interconversions together with proton conductivity) of an open-framework hybrid that combines Ca2+ ions and the rigid polyfunctional ligand 5-(dihydroxyphosphoryl)isophthalic acid (PiPhtA). Ca 2[(HO3PC6H3COOH)2] 2[(HO3PC6H3(COO)2H) (H2O)2]·5H2O (Ca-PiPhtA-I) is obtained by slow crystallization at ambient conditions from acidic (pH ≈ 3) aqueous solutions. It possesses a high water content (both Ca coordinated and in the lattice), and importantly, it exhibits water-filled 1D channels. At 75 °C, Ca-PiPhtA-I is partially dehydrated and exhibits a crystalline diffraction pattern that can be indexed in a monoclinic cell with parameters close to the pristine phase. Rietveld refinement was carried out for the sample heated at 75 °C, Ca-PiPhtA-II, using synchrotron powder X-ray diffraction data, which revealed the molecular formula Ca2[(HO3PC 6H3COOH)2]2[(HO3PC 6H3(COO)2H)(H2O)2]. All connectivity modes of the "parent" Ca-PiPhtA-I framework are retained in Ca-PiPhtA-II. Upon Ca-PiPhtA-I exposure to ammonia vapors (28% aqueous NH3) a new derivative is obtained (Ca-PiPhtA-NH3) containing 7 NH3 and 16 H2O molecules according to elemental and thermal analyses. Ca-PiPhtA-NH3 exhibits a complex X-ray diffraction pattern with peaks at 15.3 and 13.0 Å that suggest partial breaking and transformation of the parent pillared structure. Although detailed structural identification of Ca-PiPhtA-NH3 was not possible, due in part to nonequilibrium adsorption conditions and the lack of crystallinity, FT-IR spectra and DTA-TG analysis indicate profound structural changes compared to the pristine Ca-PiPhtA-I. At 98% RH and T = 24 °C, proton conductivity, σ, for Ca-PiPhtA-I is 5.7 × 10-4 S·cm-1. It increases to 1.3 × 10-3 S·cm-1 upon activation by preheating the sample at 40 °C for 2 h followed by water equilibration at room temperature under controlled conditions. Ca-PiPhtA-NH3 exhibits the highest proton conductivity, 6.6 × 10-3 S·cm-1, measured at 98% RH and T = 24 °C. Activation energies (Ea) for proton transfer in the above-mentioned frameworks range between 0.23 and 0.4 eV, typical of a Grothuss mechanism of proton conduction. These results underline the importance of internal H-bonding networks that, in turn, determine conductivity properties of hybrid materials. It is highlighted that new proton transfer pathways may be created by means of cavity "derivatization" with selected guest molecules resulting in improved proton conductivity. © 2014 American Chemical Society. Source


Perez F.,ALBA Synchrotron Light Facility
IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference | Year: 2013

ALBA is a 3 GeV, 3rd generation, synchrotron light source located in Cerdanyola del Vallès, near Barcelona (Spain), which started users operation in May 2012. In this paper we will report about the transition from commissioning to operation, the main problems faced during this first year, the actual status of the accelerators and we will provide an outlook to the next steps. Copyright © 2013 by JACoW. Source


Vallcorba O.,CSIC - Institute of Materials Science | Rius J.,CSIC - Institute of Materials Science | Frontera C.,CSIC - Institute of Materials Science | Peral I.,ALBA Synchrotron Light Facility | Miravitlles C.,CSIC - Institute of Materials Science
Journal of Applied Crystallography | Year: 2012

DAJUST is the generic name of a software package for powder diffraction formed by the core programs AJUST and SGAID (both written in Fortran) controlled by an easy-to-use Java user interface (DAJUST-UI). While AJUST performs whole-pattern matching (cell-parameter refinement, profile fitting and intensity extraction), SGAID provides a list of the most probable space groups. For the extraction of the integrated intensities, AJUST uses the Le Bail procedure but with a different formula for refining the integrated intensities. Laboratory, synchrotron X-ray and neutron sources, and both reflection and transmission experimental geometries, are supported. Other program options include automated background estimation, asymmetry correction, and corrections for absorption, variable divergence and/or illumination. The extracted intensity data are written in text format and can be directly processed by the direct methods program XLENS [Rius (2011). Acta Cryst. A67, 63-67] and the multisolution direct-space structure determination program TALP [Vallcorba, Rius, Frontera & Miravitlles (2011). Acta Cryst. A67, C272]. © 2012 International Union of Crystallography. Printed in Singapore-all rights reserved. Source

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