120 research outputs found
Nucleon mean free path in nuclear matter based on nuclear Schwinger-Dyson formalism
A mean free path of nucleon moving through nuclear matter with kinetic energy
of more than 100MeV is formulated based on the bare vertex nuclear
Schwinger-Dyson (BNSD) method in the Walecka model. The self-energy which is
derived from the higher order diagrams more than the forth order includes the
Feynman part of propagator of energetic nucleon and grows up rapidly as an
increase of kinetic energy. To avoid too large growth of these diagrams, meson
propagators are modified by introducing some form factors to take account of a
internal structure of hadron. It is confirmed that the mean free path
calculated by the BNSD method agrees good with experimental data if a
reasonable form factor is chosen, i.e., a dipole (quadrupole) type of form
factor with a cut-off parameter about 750 MeV 1000 MeV (1200 MeV
1500 MeV)
Vacuum Effects and Compressional Properties of Nuclear Matter in Cutoff Field Theory
Including the vacuum effects, the compressional properties of nuclear matter
are studied in the cutoff field theory. Under the Hartree approximation, the
low-energy effective Lagrangian is derived in the framework of the
renormalization group methods. The coefficients are determined in a way where
the physical results hardly depend on the value of the cutoff which is
conveniently introduced into the theory. It is shown that, to reproduce the
empirical data of the nucleus incompressibility, the compressibility of the
nuclear matter is favorable to be 250350MeV.Comment: PACS numbers, 21.65.+
Crystallization of the Atg12–Atg5 conjugate bound to Atg16 by the free-interface diffusion method
The Atg12–Atg5 conjugate was prepared by in vivo reconstitution and was crystallized with Atg16 using the free-interface diffusion method
Effective meson masses, effective meson-nucleon couplings and neutron star radii
Using the generalized mean field theory, we have studied the relation among
the effective meson masses, the effective meson-nucleon couplings and the
equation of state (EOS) in asymmetric nuclear matter. If the effective
omega-meson mass becomes smaller at high density, the EOS becomes stiffer.
However, if we require that the omega-meson mean field is proportional to the
baryon density, the effective omega-nucleon coupling automatically becomes
smaller at the same time as the effective omega-meson mass becomes smaller.
Consequently, the EOS becomes softer. A similar relation is found for the
effective rho-meson mass and the effective rho-nucleon coupling. We have also
studied the relation among the effective meson masses, the effective
meson-nucleon couplings and a radius R of a neutron star. The R depends
somewhat on the value of the effective omega-meson mass and the effective
omega-nucleon coupling.Comment: 29pages, 24 figure
Quark condensate in nuclear matter based on Nuclear Schwinger-Dyson formalism
The effects of higher order corrections of ring diagrams for the quark
condensate are studied by using the bare vertex Nuclear Schwinger Dyson
formalism based on - model. At the high density the quark
condensate is reduced by the higher order contribution of ring diagrams more
than the mean field theory or the Hartree-Fock
Structural Basis for Receptor-Mediated Selective Autophagy of Aminopeptidase I Aggregates
SummarySelective autophagy mediates the degradation of various cargoes, including protein aggregates and organelles, thereby contributing to cellular homeostasis. Cargo receptors ensure selectivity by tethering specific cargo to lipidated Atg8 at the isolation membrane. However, little is known about the structural requirements underlying receptor-mediated cargo recognition. Here, we report structural, biochemical, and cell biological analysis of the major selective cargo protein in budding yeast, aminopeptidase I (Ape1), and its complex with the receptor Atg19. The Ape1 propeptide has a trimeric coiled-coil structure, which tethers dodecameric Ape1 bodies together to form large aggregates. Atg19 disassembles the propeptide trimer and forms a 2:1 heterotrimer, which not only blankets the Ape1 aggregates but also regulates their size. These receptor activities may promote elongation of the isolation membrane along the aggregate surface, enabling sequestration of the cargo with high specificity
p62/SQSTM1-droplet serves as a platform for autophagosome formation and anti-oxidative stress response
Autophagy contributes to the selective degradation of liquid droplets, including the P-Granule, Ape1-complex and p62/SQSTM1-body, although the molecular mechanisms and physiological relevance of selective degradation remain unclear. In this report, we describe the properties of endogenous p62-bodies, the effect of autophagosome biogenesis on these bodies, and the in vivo significance of their turnover. p62-bodies are low-liquidity gels containing ubiquitin and core autophagy-related proteins. Multiple autophagosomes form on the p62-gels, and the interaction of autophagosome-localizing Atg8-proteins with p62 directs autophagosome formation toward the p62-gel. Keap1 also reversibly translocates to the p62-gels in a p62-binding dependent fashion to activate the transcription factor Nrf2. Mice deficient for Atg8-interaction-dependent selective autophagy show that impaired turnover of p62-gels leads to Nrf2 hyperactivation in vivo. These results indicate that p62-gels are not simple substrates for autophagy but serve as platforms for both autophagosome formation and anti-oxidative stress. Liquid-liquid phase separation of p62/SQSTM1 has been previously described, although the significance in vivo remains unclear. Here the authors show p62 droplets contain ubiquitin, autophagy-related proteins and Keap1 to serve as platform of not only autophagosome formation but also Nrf2 activation.Peer reviewe
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