In many cases, it is difficult to decouple the effect of area and thickness polydispersity, which makes sedimentation-based centrifugal separation less useful.
In natural systems, aggregation of nanoparticles makes estimating sedimentation velocity difficult because the particle size changes with aggregation (Flury and Qiu [2008]).
Dams remake coastlines and cause sedimentation in the wrong places; drowned vegetation releases a lot of methane.
These independent evidences make very unlikely the sedimentation or transfer of Loricifera or their carcasses from the oxygenated sediments surrounding the anoxic basin.
Sedimentation makes it hard to observe, and thus model, the underlying physics of how particles in a colloidal gel are attracted to each other.
Add Ca2+ back in increments with subsequent washes e.g. after resuspending cells in sedimentation buffer, add 10 μm Ca2+ (we make up a 100 mM stock CaCl2, sterile filtered; and add 10 μl stock/10 ml sedimentation buffer).
Researchers in other fields, however, were still conservatively sticking with ages on the order of several hundred million, but were revising their assumed sedimentation rates downward in order to make room for expanded time concepts.
Even after coagulation and flocculation, sedimentation does not remove enough suspended impurities from water to make it crystal clear.
We cannot make a direct comparison to Bujalowski et al. (1988) because their sedimentation studies were done as a function of Mg++ concentration; in addition, their concentration of SSB was sub-saturating (either 101 or 87 nts per tetramer).
This uniform sedimentation behavior made it possible for us to use analytical ultracentrifugation as a quantitative binding assay.
