Science

Science | Research/Notes by Aiann Oishi
flat =﻿ Cell Migration = **What is it?**
 * process of required movement of cells in “particular directions to specific locations” to aid tissue formation in the embryonic, healing and immune response stages
 * if errors occur during the process, serious mental, vascular diseases and tumors can form
 * scientists want to learn more about cell migration to develop new therapeutic methods of controlling tumor cells
 * //chemotaxis// – when cells move towards specific external signals


 * Studying migration**
 * movement of cells are slow so films are taken of the glass slides and viewed at high speed

1. cells at the front advance Two models: Cytoskeletal and Membrane Flow __Cytoskeletal__ Proteins formed at the front push, force cells forward __Membrane Flow__ Proteins returned to the front, increasing the supply of fresh molecules or “feet” and stabilize the front part of the cell.
 * How does it work?**
 * movement of all mammal-based cells (except sperm) are similar, common features are present

Uncertain – are the cells at the rear pulled forward? There is a clear frontand back in migrating cells

Source (Wikipedia)

Vicente-Manzanares, Miguel, Donna J. Webb, and A. Rick Horwitz. "Cell migration at a glance." //Journal of Cell Science//. 21.118 (2005): 4917-19. Web.
 * Diagrams & Additional Readings**

View PDF: [|JournalofCellScience_vol118.pdf]

[|Source (Journal of Cell Science)]



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= Molecular Diffusion (in Physics) = **What is it?**
 * process of molecules moving among each other because of their kinetic energy and immune response stages
 * kinetic energy - energy of motion
 * diffusion occurs when individual molecules become evenly dispersed in a contained area
 * all molecules are contantly moving because of their kinetic energy
 * temperature and size affect the rate of diffusion
 * molecules tend to move from an area of higher concentration to an area of lower concentration


 * Molecular diffusion in Biology**
 * water and other molecules are transported across biological membranes by: diffusion and osmosis
 * osmosis and diffusion processes are //passive transport// because the membranes are not actively involved

Source (Georgia State University)

Animation: How Diffusion Works

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= Geophysical Diffusion = **What is it?**
 * to create a more accurate image of the subsurface, geophysical events are moved (space and time-wise) to a subsurface location, instead of the original surface location
 * geophysical events are changes in energy
 * examples like faults, folding of the crust make subsurface images hard to create without this migration process

quicker and use average values used for less complex surfaces more expensive, uses full values, higher quality image
 * Types**
 * __Time Migration__
 * __Depth Migration__

Source (Wikipedia)



--- = Planetary Diffusion = **What is it?** **Types**
 * occurs when planetary orbits are changed because of interactions with gas disks, other planets in the system
 * became more widely known in the 1980s when Drs. Peter Goldreich and Scott Tremaine investigated the possibility of orbits changing
 * Gas-Disk Migration or Type I
 * Planetesimal-Driven Migration or Type II
 *  Planet-Planet Migration

Source (Wikipedia) [|Source (Scholarpedia)]



= Electromigration = **What is it?**
 * transport or movement of material in a conductor under the influence or due to the momentum of an applied electric field
 * conductor – a material that allows the flow of energy to take place, ex. aluminum and copper
 * electromigration causes reliability problems in electronic devices
 * atomic migration is caused by electromigration – it is a combination of direct and wind forces
 * microstructure, temperature, and material determine the type and intensity of damage caused by electromigration
 * the most common cause is high density currents in tight conductors

Source (University of Cambridge) "Electromigration for Designers" Article



= Sedimentation = **What is it?**
 * the process of settling floating deposits or solids in a fluid

Source (Britannica)