I have really only focused on the introduction portion of this paper so far.  The main point is that they present an alternative explanation of the mechanism of marginal regeneration.  Here is my interpretation/summary of the process based on their explanation:

1. A film element falls into the Plateau border
2. The thickness of the element increases, causing the surface area to decrease.  As a result, the surfactant concentration increases.
3. This occurs all along the border (they only consider the lower border),
4. In order for the surfactant distribution to equilibriate, the saturated layer becomes unstable, with some elements gaining even higher concentration, others having a normal coverage
5. The elements with high concentration have lower surface tension than their surroundings, and are pulled back into the film where they can expand (vertically)
6. The elements (now in the bulk) continue to expand in order to reach the same coverage as the surrounding film.  To do this, they must end up thinner (i.e. longer vertically) than they had started, due to the "extra" surfactant they picked up in the instability process.
7. These elements are now effectively black film.  They are thinner and lighter than their neighbors, and will rise as a buoyancy effect.

If you interpreted their explanation differently, please correct me.

A few questions:

 - Why does the film element "fall" into the border in the first place?  Is it capillary suction, gravity, both?  If it is capillary suction, why do they focus so much on the lower border?  Shouldn't it occur the exact same way at other borders?

 - This idea of the instability of surfactant concentration is interesting.  It is unclear to me if they recover this mathematically (admittedly, I have not read the rest of the paper...).  How does this instability change with our magnetic particles?  Or, can we devise an experiment to verify/refute this claim that the instability and Marangoni flow drive the marginal regeneration?

 - Why is it necessarily the surfactant concentration that wants to reach equilibrium and not, for instance, the thickness?

 - Somewhere in this process some of the film, or the fluid inside the film, is departing entirely through the borders.  Hence the overall draining effect.  Where does that fit in in this process?

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