2,140 research outputs found
Two-Step Contribution to Intermediate Energy (p,p') and (p,n) Reactions
We calculate the two-step contribution to (p,p') and (p,n) reactions at
intermediate energy. We describe the motion of the incident nucleon with plane
wave and compare the contribution from the two-step processes with that from
the one-step processes. To describe the two-step processes, we extende the
response functions into the nondiagonal ones with respect to the momentum
transfer q.
We performed a numerical calculation for the cross sections of the C,
Ca(p,p') scatterings and the spin longitudinal and the spin transverse
cross sections of the C,Ca(p,n) reactions at 346 MeV and 494 MeV.
We found that the two-step contribution is appreciable in comparison with the
one-step processes in higher energy transfer region for the spin longitudinal
and the spin transverse (p,n) reactions. We also found that the two-step
processes give larger contribution to the spin transverse (p,n) reaction than
to the spin longitudinal reaction. This finding is very encouraging to
interpret the discrepancy between the DWIA calculation and the experimental
results of the spin longitudinal and the spin transverse cross sections.Comment: LaTeX, 18 pages, 11 Postscript file
E1-Like Activating Enzyme Atg7 Is Preferentially Sequestered into p62 Aggregates via Its Interaction with LC3-I
p62 is constitutively degraded by autophagy via its interaction with LC3. However, the interaction of p62 with LC3 species in the context of the LC3 lipidation process is not specified. Further, the p62-mediated protein aggregation's effect on autophagy is unclear. We systemically analyzed the interactions of p62 with all known Atg proteins involved in LC3 lipidation. We find that p62 does not interact with LC3 at the stages when it is being processed by Atg4B or when it is complexed or conjugated with Atg3. p62 does interact with LC3-I and LC3-I:Atg7 complex and is preferentially recruited by LC3-II species under autophagic stimulation. Given that Atg4B, Atg3 and LC3-Atg3 are indispensable for LC3-II conversion, our study reveals a protective mechanism for Atg4B, Atg3 and LC3-Atg3 conjugate from being inappropriately sequestered into p62 aggregates. Our findings imply that p62 could potentially impair autophagy by negatively affecting LC3 lipidation and contribute to the development of protein aggregate diseases. © 2013 Gao et al
- …