September 2006 Archives

Scientists from CNRS at the University J. Fourier of Grenoble and from the European Synchrotron Radiation Facility (ESRF) have recently succeeded in constructing 3D pictures of a living plant seed using the holotomography technique with synchrotron light. This revealed the presence of a network of voids between the cells that may be used for storing the oxygen needed for efficient germination. For more information, see the paper, "Quantitative phase tomography of Arabidopsis seeds reveals intercellular void network", P. Cloetens et al., Proceedings of the National Academy of Sciences, published online before print September 14, 2006.

At the FLASH facility at DESY, Hamburg, the free-electron laser (FEL) generated laser light flashes at wavelengths between 13.5 and 13.8 nm with an average power of 10 mW and record energies of up to 170 µJ/pulse at repetition rates of 150 Hz. Since the pulses have a duration of only around 10 fsec, the peak power can reach 10 GW/pulse. These powers are larger than is currently available at even the biggest plasma X-ray laser facilities worldwide. The use of the fifth harmonic (2.7 nm) enables FLASH to reach deep into the water window, which is crucially important for the investigation of biological samples. For more information, contact Petra Folkerts, Press officer XFEL project, FLASH, DESY, Phone: +49-40-8998-4977, Fax: +49-40-8998-2020, petra.folkerts@desy.de, http://www.xfel.net

Professor Hutchings (Cardiff University, UK) and his colleagues recently published some interesting results on vanadium phosphates (VPOs). VPOs are catalysts used in industry to spur the partial oxidation of n-butane to maleic anhydride, which is then used as a starting material for products such as resins and lubricants. The research group utilized in-situ powder X-ray diffraction, in addition to laser Raman and electron paramagnetic resonance spectroscopies. They determined the transformation of VPO phases as a function of temperature and with various reactants and products present over the catalyst. They concluded that the presence of the reactants rapidly converts w-VOPO₄ to d-VOPO₄, but that the initial formation of the phase may create V⁺⁵ sites associated with increased catalytic activity. For more information, see the paper, "Chemically Induced Fast Solid-State Transitions of w-VOPO₄ in Vanadium Phosphate Catalyst ", M. Conte et al., Science. 313, 1270 (2006).