Localized Character of 4f Electrons in CeRhx_x(x=2,3) and CeNix_x(x=2,5)

We have measured Ce 4f spectral weights of extremely $\alpha$-like Ce-transition metal intermetallic compounds CeRh$_x$ (x=2,3) and CeNi$_x$ (x=2,5) by using the {\it bulk-sensitive} resonant photoemission technique at the Ce $M_5$($3d_{5/2}\to4f$)-edge. Unprecedentedly high energy resolution and longer escape depth of photoemitted electron at this photon energy enabled us to distinguish the sharp Kondo resonance tails at the Fermi level, which can be well described by the Gunnarsson-Sch\"onhammer(GS) calculation based on the Anderson Impurity Hamiltonian. On the other hand, the itinerant 4f band description shows big discrepancies, which implies that Ce 4f electrons retain localized characters even in extremely $\alpha$-like compounds.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let

Faithful chaperones

This review describes the properties of some rare eukaryotic chaperones that each assist in the folding of only one target protein. In particular, we describe (1) the tubulin cofactors, (2) p47, which assists in the folding of collagen, (3) α-hemoglobin stabilizing protein (AHSP), (4) the adenovirus L4-100 K protein, which is a chaperone of the major structural viral protein, hexon, and (5) HYPK, the huntingtin-interacting protein. These various-sized proteins (102–1,190 amino acids long) are all involved in the folding of oligomeric polypeptides but are otherwise functionally unique, as they each assist only one particular client. This raises a question regarding the biosynthetic cost of the high-level production of such chaperones. As the clients of faithful chaperones are all abundant proteins that are essential cellular or viral components, it is conceivable that this necessary metabolic expenditure withstood evolutionary pressure to minimize biosynthetic costs. Nevertheless, the complexity of the folding pathways in which these chaperones are involved results in error-prone processes. Several human disorders associated with these chaperones are discussed

ESR of some RE-ions in CePd3

Nous donnons quelques résultats de la ESR de Gd3+, Er3+ et YB3+ dans le composé CePd3 à basse température. Les résultats sont discutés en considérant que CePd3 est un composé avec fluctuations de valence.Some results of the ESR of Gd3+, Er3+ and Yb3+ in the intermetallic host CePd3 at temperatures of 1.5-4.2 K in X-band and 3.5-120 K in Q-band are reported. For the Gd3+ resonance in a CePd3 single crystal CEF-splitting appropriate to a cubic local environment is observed. The strong non-linear but exponential increase of linewidth of Yb3+ in CePd3 is explained by an additional contribution to the relaxation of the 4f momentum due to a resonant phonon relaxation process. The results are discussed with respect to the fact that CePd3 is an intermetallic compound, which shows interconfiguration fluctuations (ICF)