76 research outputs found

    Band Calculation for Ce-compounds on the basis of Dynamical Mean Field Theory

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    The band calculation scheme for ff electron compounds is developed on the basis of the dynamical mean field theory (DMFT) and the LMTO method. The auxiliary impurity problem is solved by a method named as NCAf2f^{2}v', which includes the correct exchange process of the f1f2f^{1} \to f^{2} virtual excitation as the vertex correction to the non-crossing approximation (NCA) for the f1f0f^{1} \to f^{0} fluctuation. This method leads to the correct magnitude of the Kondo temperature, TKT_{\rm K}, and makes it possible to carry out quantitative DMFT calculation including the crystalline field (CF) and the spin-orbit (SO) splitting of the self-energy. The magnetic excitation spectra are also calculated to estimate TKT_{\rm K}. It is applied to Ce metal and CeSb at T=300 K as the first step. In Ce metal, the hybridization intensity (HI) just below the Fermi energy is reduced in the DMFT band. The photo-emission spectra (PES) have a conspicuous SO side peak, similar to that of experiments. TKT_{\rm K} is estimated to be about 70 K in γ\gamma-Ce, while to be about 1700 K in α\alpha-Ce. In CeSb, the double-peak-like structure of PES is reproduced. In addition, TKT_{\rm K} which is not so low is obtained because HI is enhanced just at the Fermi energy in the DMFT band.Comment: 30pages, 18 figure

    The Intriguing Life of Autophagosomes

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    Autophagosomes are double-membrane vesicles characteristic of macroautophagy, a degradative pathway for cytoplasmic material and organelles terminating in the lysosomal or vacuole compartment for mammals and yeast, respectively. This highly dynamic, multi-step process requires significant membrane reorganization events at different stages of the macroautophagic process. Such events include exchange and flow of lipids and proteins between membranes and vesicles (e.g., during initiation and growth of the phagophore), vesicular positioning and trafficking within the cell (e.g., autophagosome location and movement) and fusion of autophagosomes with the boundary membranes of the degradative compartment. Here, we review current knowledge on the contribution of different organelles to the formation of autophagosomes, their trafficking and fate within the cell. We will consider some of the unresolved questions related to the molecular mechanisms that regulate the “life and death” of the autophagosome
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