Probe spectra interpreted with the Gaussian assumption

studied diffusion of probe particles in F-actin networks, using video tracking microscopy to observe particle motion(112). Mean-square displacements were measured directly. They were not diffusive ((Ax) ) was not t. Particle dynamics were heterogeneous. Some particles were completely trapped, never moving far from their starting points other particles alternately were trapped within restricted regions and made rare saltatory jumps. 

16 Probe spectra interpreted with the Gaussian assumption 

This section notes a series of papers, sometimes linked under the cognomen microrheology, that rely on the assertion that the incoherent structure factor 

It is important to emphasize that even if a measurable is not simply related to underlying physical properties, the measurable may still represent a valuable practical analytical tool for industrial purposes(114). Kaplan, et al. used DWS to study structure formation in alkyl ketene dimer emulsions(l 15). These systems are used in paper manufacture as sizing agents, but lead to technical difficulties if they gel, which they sometimes do. Within a few days, spectra of systems that were going to gel could readily be distinguished from spectra of systems that would remain stable. 

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