24 research outputs found
Shape Changes of Self-Assembled Actin Bilayer Composite Membranes
We report the self-assembly of thin actin shells beneath the membranes of
giant vesicles. Ion-carrier mediated influx of Mg2+ induces actin
polymerization in the initially spherical vesicles. Buckling of the vesicles
and the formation of blisters after thermally induced bilayer expansion is
demonstrated. Bilayer flickering is dominated by tension generated by its
coupling to the actin cortex. Quantitative flicker analysis suggests the
bilayer and the actin cortex are separated by 0.4 \mum to 0.5 \mum due to
undulation forces.Comment: pdf-file, has been accepted by PR
Eight-component two-fermion equations
An eight-component formalism is proposed for the relativistic two-fermion
problem. In QED, it extends the applicability of the Dirac equation with
hyperfine interaction to the positronium case. The use of exact relativistic
two-body kinematics entails a CP-invariant spectrum which is symmetric in the
total cms energy. It allows the extension of recent \alpha^6 recoil corrections
to the positronium case, and implies new recoil corrections to the fine and
hyperfine structures and to the Bethe logarithm.Comment: Revtex, accepted for publication in Phys. Rev.