Kondo quasiparticle dynamics observed by resonant inelastic x-ray scattering.

Effective models focused on pertinent low-energy degrees of freedom have substantially contributed to our qualitative understanding of quantum materials. An iconic example, the Kondo model, was key to demonstrating that the rich phase diagrams of correlated metals originate from the interplay of localized and itinerant electrons. Modern electronic structure calculations suggest that to achieve quantitative material-specific models, accurate consideration of the crystal field and spin-orbit interactions is imperative. This poses the question of how local high-energy degrees of freedom become incorporated into a collective electronic state. Here, we use resonant inelastic x-ray scattering (RIXS) on CePd3 to clarify the fate of all relevant energy scales. We find that even spin-orbit excited states acquire pronounced momentum-dependence at low temperature-the telltale sign of hybridization with the underlying metallic state. Our results demonstrate how localized electronic degrees of freedom endow correlated metals with new properties, which is critical for a microscopic understanding of superconducting, electronic nematic, and topological states.

[Detection of low lipase activities in food]. / Nachweis niedriger Lipase-Aktivitäten in Lebensmitteln.

A spectrofluorimetric procedure using 4-methylumbelliferyl esters as substrates was developed for the determination of lipase activity in foods. It was tested with among others whey and egg powders, almonds, pepper, paprika and cinnamon. In addition, some lipase preparations of microbial origin were analyzed. The detection limit of the method is one to two orders of magnitude lower than that of a test paper which contains indoxyl acetate as the substrate.

Autoxidation of phenyl linoleate and phenyl oleate: HPLC analysis of the major and minor monohydroperoxides as phenyl hydroxystearates.

Phenyl linoleate was oxidized under different conditions. The monohydroperoxide products were isolated and subsequently hydrogenated. The isomers of phenyl hydroxysterate obtained were separated by high pressure liquid chromatography. On the basis of cochromatography with reference materials and mass spectroscopy, it was shown that the mixture was composed mainly (96%) of phenyl 9-hydroxy- and phenyl 13-hydroxysterates (9- and 13-HOPh) with 8-, 10-, 12- and 14-HOPh as minor compounds (4%). In the minor fraction, the 8- and 14-HOPh predominated in comparison to the 10- and 12-HOPh. The presence of α-tocopherol in the autoxidation experiment changed the proportion of the phenyl hydroxystearate isomers: the proportion of the 9- and 13-HOPh increased and those of the 8- and 14-HOPh decreased. After addition of 0.05% or higher concentrations of α-tocopherol, the minor fraction comprised approximately equal amounts of 8-, 10-, 12- and 14-HOPh. Autoxidation of phenyl oleate followed by hydrogenation of the monohydroperoxides resulted in the formation of a mixture of phenyl hydroxystearates containing approximately equal amounts of 8-, 9-, 10- and 11-HOPh.