Excited state absorption in Mn2+ doped phosphate glass.

The possibility of obtaining laser action from Mn2+ doped glass has been investigated. The excited state absorption at the expected laser wavelength was measured and explains the unsuccessful attempts to obtain laser action

Index matching between passive and active tellurite glasses for use in microstructured fiber lasers: Erbium doped lanthanum-tellurite glass

Active and passive variants of La-containing tellurite glasses have been developed with matched refractive indices. The consequences of adding lanthanum to the glass was studied through measurements of the crystallization stability, glass viscosity and the loss of unstructured fibers. Doping the glass with erbium allowed for any spectroscopic changes to be observed through measurements of the absorption and energy level lifetimes. The fluorescence emission spectra were measured at 1.5 microm and, to the best of our knowledge, for the first time in tellurite glass at 2.7 microm.Michael R. Oermann, Heike Ebendorff-Heidepriem, Yahua Li, Tze-Cheung Foo, and Tanya M. Monrohttp://www.opticsinfobase.org/abstract.cfm?URI=oe-17-18-1557

Le projet DYLAN ou les enjeux politiques, cognitifs et stratégiques du plurilinguisme

Composed of 19 universities from 12 countries, the Dylan Project is an integrated project (IP) of the 6th Framework Programme of the European Union, under Priority 7 « Citizenship and governance in a knowledge-based society ».The project addresses the core issue underlying topic 3.3.1: establish whether and how a European knowledge based society designed to ensure economic competitiveness and social cohesion can be created within a European Union that is linguistically more diverse than ever. The overarching objectives are to show that, in this respect, the linguistic diversity prevalent in Europe is potentially an asset rather than an obstacle and to identify the conditions under which individual and societal multilingualism can be turned to advantage.It will show in what ways the usage of multilingual repertoires can promote the creation and the transfer of knowledge (cognitive asset) and have an impact on communication control, problem solving and decision making (strategic asset), in the diversity of economic, political and educational contexts

A cysteine proteinase in the penetration glands of the cercariae of Cotylurus cornutus (Trematoda, Strigeidae)

A cysteine proteinase from the penetration glands of Cotylurus cornutus cercariae was examined with histochemical and biochemical methods. The enzyme hydrolyzed gelatin, azocoll, azocasein, azoalbumin, N-blocked-l-arginine-4-methoxy-2-naphthylamide, and N-blocked-p-nitroanilide, but did not degrade elastin. The metal ion complexane ethylenediamine tetraacetate and the thiol-reducing compound dithioerythritol enhanced the proteinase activity, whereas the thiol-blocking compounds p-hydroxymercuribenzoate and N-ethylmaleimide (NEM) inhibited it. The enzyme was also sensitive to leupeptin but insensitive to soybean trypsin inhibitor. An electrophoretic separation of extract proteins from the cercariae under acidic, non-denaturing conditions and in the presence of 0.1% gelatin in a polyacrylamide gel revealed the presence of two distinct and three weak transparent bands in the gel resulting from a gelatinolytic activity at pH 6.8. The distinct bands apparently resulted from the activity of the glandular enzyme and lysosomal cathepsin B, whereas the weak ones presumably indicated these enzymes partially degraded in the course of the preparative procedure. No gelatinolysis occurred following treatment of an extract sample with 0.1 mM NEM

Unexpected luminescence of Cr5+ and Cr3+ ions in ZrSiO4 zircon crystals

Luminescence, decay-times and EPR spectroscopy of Cr-doped ZrSiO4 show the presence of both Cr3+ and Cr5+ active centers, which can be connected with Zr4+ and Si4+ adjacent two-cation replacement. Cr5+ emission occurs within a similar spectral range as for Cr4+ and hence confusion is possible