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The typical discarding of the low-frequency signals in BOLD-contrast imaging came into question in 1995, when it was observed that the "noise" in the area of the brain that controls right-hand movement fluctuated in unison with similar activity in the area on the opposite side of the brain associated with left-hand movement. [1] BOLD-contrast ...
This mechanism for image contrast changes corresponding to changes in neuronal activity was first proposed by Dr. Patrick Stroman in 2001. [1] [2] SEEP contrast is based on changes in tissue water content which arise from the increased production of extracellular fluid [3] [4] and swelling of neurons and glial cells at sites of neuronal activity.
In materials science, Coble creep, a form of diffusion creep, is a mechanism for deformation of crystalline solids. Contrasted with other diffusional creep mechanisms, Coble creep is similar to Nabarro–Herring creep in that it is dominant at lower stress levels and higher temperatures than creep mechanisms utilizing dislocation glide. [1]
Dislocation creep is a deformation mechanism in crystalline materials.Dislocation creep involves the movement of dislocations through the crystal lattice of the material, in contrast to diffusion creep, in which diffusion (of vacancies) is the dominant creep mechanism.
Sample deformation mechanism map for a hypothetical material. Here there are three main regions: plasticity, power law creep, and diffusional flow. A deformation mechanism map is a way of representing the dominant deformation mechanism in a material loaded under a given set of conditions. The technique is applicable to all crystalline materials ...
In other words, it is the movement of dislocations in the material which allows for deformation. If we want to enhance a material's mechanical properties (i.e. increase the yield and tensile strength), we simply need to introduce a mechanism which prohibits the mobility of these dislocations. Whatever the mechanism may be, (work hardening ...
The transport mechanism depends on the material being moved. Intracellular transport that requires quick movement will use an actin-myosin mechanism while more specialized functions require microtubules for transport. [5] Microtubules function as tracks in the intracellular transport of membrane-bound vesicles and organelles.
A solid is a material that can support a substantial amount of shearing force over a given time scale during a natural or industrial process or action. This is what distinguishes solids from fluids, because fluids also support normal forces which are those forces that are directed perpendicular to the material plane across from which they act and normal stress is the normal force per unit area ...