http://www.esrf.eu The latest scientific news daily 1 2006-03-23T07:14:04Z http://www.esrf.eu/news/spotlight/spotlight183/index_html The Verwey transition in magnetite is one of the longest unsolved problems of solid state physics, where the otherwise excellent theories fail to capture the collective nature of the first-order phase transition. A recent inelastic X-ray scattering (IXS) study revealed an anomalous broadening of specific phonon modes in a broad temperature range down to the Verwey transition at 124 K. Accompanying ab initio lattice dynamics calculations suggest the origin of this broadening to be strong phonon anharmonicity induced by electron-phonon coupling, thus indicating that the Verwey transition is a cooperative phenomenon which involves a wide spectrum of phonons coupled to the electron charge fluctuations. 2013-05-15 10:40:08 No publisher admans 2013-05-15T08:40:08Z News Item http://www.esrf.eu/news/spotlight/spotlight182/index_html FAM3B PANDER is involved in the regulation of glucose homeostasis and β cell function and FAM3C ILEI is implicated in cancer. They had both been predicted to be classical cytokines with three dimensional structures based on a 4-helix bundle. The crystal structure of FAM3B PANDER, solved by exploiting the anomalous scattering of sulphur atoms inherent to the amino acid sequence of the protein has revealed that, contrary to expectations, PANDER adopts a novel, globular β-β-α fold that is conserved throughout the FAM3 superfamily. This superfamily most likely represents a novel class of signalling molecules with a mode of action distinct to that of the well-known four-helix bundle cytokines. 2013-04-30 08:00:00 No publisher admans 2013-05-06T06:38:16Z News Item http://www.esrf.eu/news/spotlight/spotlight181/index_html Semi-solid casting is a promising process for the production of light-weight metallic components. However, a semi-solid melt exhibits unpredictable flow and filling dynamics when it is injected into thin-walled components. The former were studied by injecting a semi-solid Al-Ge alloy into a thin channel while recording high-resolution radiographs at fast acquisition rates of up to 1000 images/s. Single particle trajectories and rapid break-up of solid skeletons were observed in situ for the first time. 2013-04-16 08:00:00 No publisher admans 2013-04-16T15:37:22Z News Item http://www.esrf.eu/news/spotlight/spotlight180/index_html The interface between two of the most popular band insulating oxides, LaAlO3 and SrTiO3, is conducting under certain conditions due to the formation of a high mobility 2D-electron gas, a discovery made in 2004 by Ohtomo and Hwang [1]. Here, by using a combination of advanced X-ray synchrotron-based spectroscopic and structural measurements, we show that this phenomenon is linked to a structural and electronic reconstruction of the interface which precede the appearance of the 2D-electron gas. The results challenge some of the most accredited theoretical models describing this system. 2013-04-02 08:00:00 No publisher admans 2013-03-28T07:52:00Z News Item http://www.esrf.eu/news/spotlight/spotlight179/index_html Two new phases of Mn2O3, corundum-type and perovskite-type Mn2O3, were obtained by high-pressure high-temperature synthesis. The observation of the perovskite structure in simple Mn2O3 challenges the main conjecture of perovskite science and technology which so far assumed a strict separation of the A- and B-sites in the crystal structure: the former being occupied by electronically inactive (alkali, alkali-earth, rare-earth) metals and the latter by transition metals. 2013-03-19 18:15:00 No publisher admans 2013-03-19T16:16:11Z News Item http://www.esrf.eu/news/spotlight/spotlight178/index_html Arsenate and phosphate are both common on Earth and have very similar chemical properties. However, phosphate is vital to life while arsenate is toxic. Discrimination by proteins between arsenate and phosphate is thus essential to the survival of living organisms, particularly those found in environments rich in arsenate. A comparison of the ultra high resolution crystal structures of a phosphate binding protein in complex with either phosphate or arsenate has allowed the elucidation of the mechanism for phosphate discrimination and revealed this to be based on the geometry of negative-charge-assisted hydrogen bonds formed between arsenate and phosphate anions and the protein. 2013-03-06 09:00:00 No publisher admans 2013-03-06T07:04:54Z News Item http://www.esrf.eu/news/spotlight/spotlight177/index_html Calcite and dolomite, two of the most common minerals on the Earth’s surface, undergo phase transitions at high pressure. Their structures have be identified by single-crystal diffraction experiments under extreme conditions. Dolomite-III, in particular, was found to be triclinic with 80 atoms in the unit cell and has unexpected structural complexity. It is thermodynamically stable at the high pressures and temperatures found in the Earth’s interior, and may constitute a significant carbon repository in the lower mantle. 2013-02-20 18:45:00 No publisher admans 2013-02-21T10:39:27Z News Item http://www.esrf.eu/news/spotlight/spotlight176/index_html Gold nanoparticles were grown on the surface layer (S-layer) of the outer cell wall of the thermoacidophilic archaeon Sulfolobus acidocaldarius. Cysteine residues in the cell wall provide sulphur atoms that render the Au paramagnetic by increasing the number of holes in its 5d band. The paramagnetic response of the nanopaticles to an external field was measured using XMCD at the Au L2,3 absorption edges. 2013-02-05 18:08:34 No publisher admans 2013-02-05T16:08:34Z News Item http://www.esrf.eu/news/spotlight/spotlight175/index_html Some of the animals living in the sea have blue blood. The origin of this blue colour is a protein called hemocyanin that contains copper bound to molecular oxygen: an essential interaction allowing these animals to live. Scientists at the ESRF have unravelled the structure of octopus hemocyanin by means of the small-angle X-ray scattering technique in conjunction with data modelling using the algorithm QUAFIT. 2013-01-23 11:00:00 No publisher admans 2013-01-23T15:00:07Z News Item http://www.esrf.eu/news/spotlight/spotlight174/index_html KillerRed, a red fluorescent protein, generates highly-cytotoxic reactive oxygen species when illuminated with strong light. The molecular mechanism of the laser-induced photo-conversion that results in a photobleached state of the molecule has been elucidated for a highly photosensitive mutant of KillerRed by using X-ray crystallography combined with UV/Visible spectroscopy. These results will help in the design of new improved photosensitive or photoresistant fluorescent proteins for chomophore-assisted light inactivation and may even provide the basis for enhanced photodynamic cancer therapy. 2012-12-24 09:00:00 No publisher admans 2012-12-20T15:46:36Z News Item http://www.esrf.eu/news/spotlight/spotlight173/index_html The type of magnetism exhibited by a material can be dependent on the size of the particle, with nanoscale clusters behaving differently to the bulk material. Rhodium clusters of around 150 atoms have been investigated using XMCD to examine the magnetic behaviour of itinerant electron systems close to the onset of stable ferromagnetism. 2012-12-11 18:44:49 No publisher admans 2012-12-12T07:12:05Z News Item http://www.esrf.eu/news/spotlight/spotlight172/index_html Nanoparticular titanium dioxide is one of the most commonly used nanomaterials. In this study, the speciation and distribution of titanium in cucumber plants exposed to titanium dioxide nanoparticles were investigated to determine whether the nanoparticles could enter into the food chain via agricultural products. 2012-11-27 19:00:00 No publisher admans 2012-11-29T07:30:14Z News Item http://www.esrf.eu/news/spotlight/spotlight171/index_html Glasses are often considered as archetypes for systems far from thermodynamical equilibrium. Understanding their physical ageing is essential for technological applications as well as for fundamental research. For the first time, researchers have investigated the ageing of metallic glasses at the atomic length scale. They found strong similarities between the behaviour of metallic glasses and the behaviour of many soft materials, suggesting the existence of a universal mechanism driving the ageing of out-of-equilibrium systems. 2012-11-13 18:00:00 No publisher admans 2012-11-13T16:02:50Z News Item http://www.esrf.eu/news/spotlight/spotlight170/index_html Direct observation of geometrical carrier localisation in single hexagonal core-multishell nanowires was used by researchers at the ESRF to demonstrate that size-dependent phenomena at the nanoscale can be imaged by X-ray excited optical luminescence. This research provides a glimpse of the potential that a hyperspectral imaging method can provide. 2012-10-30 09:00:00 No publisher admans 2012-10-25T07:45:40Z News Item http://www.esrf.eu/news/spotlight/spotlight169/index_html Dipolar interactions between colloidal particles generate unusual self-organised architectures that could pave the way to novel applications. Magnetic core-shell nanoparticles in suspension were recently studied at the ESRF. Their self-assembly was shown to proceed with the formation of 1D chains, 2D sheets and eventually 3D crystalline structures. Because the particle size is comparable to the wavelength of light, these structures possess photonic properties that can be easily manipulated by an external stimulus such as a moderate magnetic field. 2012-10-16 10:39:33 No publisher admans 2012-10-16T08:40:40Z News Item