Surface enhancement of oxygen exchange and diffusion in the ionic conductor La2Mo2O9

Isotopic surface oxygen exchange and its subsequent diffusion have been measured using secondary ion mass spectrometry in the fast ionic conductor La2Mo2O9. A silver coating was applied to the sample surface to enhance the surface exchange process for dry oxygen. Contrary to previous studies performed using a wet atmosphere, no grain boundary diffusion tail was observed under these optimized dry exchange conditions. The activation energy for oxygen diffusion was found to be 0.66(+/- 0.09) eV at high temperature (>570 degrees C), and 1.25(+/- 0.01)eV at low temperature (<570 degrees C). Time-of-Flight secondary ion mass spectrometry was employed to investigate the correlation between the silver coating and the O-18 concentration on the sample surface. A close correlation between the presence of silver and oxygen incorporation on the surface was observed. (C) 2010 Elsevier B.V. All rights reserved

A peer-to-peer network to support scholarly communication

The number of scientific journals and thereby the number of published articles grew with an enormous rate in the last century (e.g. Price 1986; Henderson 2002). In the second half of the 20th century the system seemed to abut against its boundaries, because in relation to research budgets, library budgets did not grow fast enough to cover all the scientific output produced. Price increases well above the inflation rate set by commercial publishers that bundle disproportionately high market power – especially for journals in the Science-Technical- Medicine-Sector in the last thirty years – intensified the situation even further. This situation is known as the serial crisis. New Information and Communication Technology (ICT) driven publication models are established and seem to be a promising way out of the crisis because they reduce distribution costs significantly. Especially the open access (OA) movement that advocates free electronic access to scientific output is subject to a fierce public debate. In this paper we will detail problems associated with OA and suggest a Peer-to-Peer (P2P) system that supports electronic scholarly communication as a tool to address the economic problems mentioned above

Localization of cholesterol in rat cerebellum with imaging TOF-SIMS Effect of tissue preparation

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) was utilized to address the issue of cholesterol localization in rat cerebellum, a subject not previously investigated.Rat cerebellum was prepared by three different procedures: (1) fixation in formaldehyde, freeze-protection by sucrose, freezing in liquid nitrogen and sectioning by cryoultramicrotomy and drying at room temperature or (2) freezing in liquid nitrogen, cryostat sectioning at −40 \ub0C and drying at room temperature or (3) high-pressure freezing, freeze-fracturing and freeze-drying.The samples were analyzed in an imaging TOF-SIMS instrument equipped with a Bi1–7+-source. The cholesterol signal (m/z 369 and 385), showed high intensity in the glial cells in white matter and lower intensity in Purkinje cells and in nuclei of granular layer cells. Specimen treated by procedure 1 showed some signs of diffusion of cholesterol in the tissue. Specimen treated by procedure 2 showed freeze-damage of the cells. Specimen treated by procedure 3 showed distinct localization of cholesterol in well preserved tissue. Thus, high-pressure freezing and freeze-fracturing was used for further characterization of the distribution of cholesterol in rat cerebellum