Heat conduction in the vortex state of NbSe2: evidence for multiband superconductivity

The thermal conductivity kappa of the layered s-wave superconductor NbSe2 was measured down to T(c)/100 throughout the vortex state. With increasing field, we identify two regimes: one with localized states at fields very near H(c1) and one with highly delocalized quasiparticle excitations at higher fields. The two associated length scales are naturally explained as multiband superconductivity, with distinct small and large superconducting gaps on different sheets of the Fermi surface. This behavior is compared to that of the multiband superconductor MgB2 and the conventional superconductor V3Si.

A rapid and simple assay for the study of thromboxane B2 synthesis by intact human platelets

Conversion of 1-14C-arachidonic acid (AA) to thromboxane B2 (TXB2) by human platelets was studied by using a new, simple technique. Organic solvent extraction was avoided by spotting aliquots of the reaction mixture directly on thin layer chromatography (TLC) plates. In this way it was possible to study the kinetic parameters of the formation of TXB2. Moreover, the rapidity and simplicity of the assay should be particularly suitable when studying the possible relationships between thromboxane synthesis and aggregation function in human platelets, where a large number of determinations is required.