====== Mammalian cell colony growth ======
A mammalian cell colony is modeled as a set of contacting deformable particles. A particle can be substituted by a pair of new particles that models the process of cell division. Specific features of this simulation are:

  * Particles have arbitrary shapes defined by real functions;
  * Particles follow particular rules of behaviour;
  * Communication between particles is defined by a collision (interpenetration) detection algorithm;
  * For simulation of a deformable particle, we dynamically change its shape, size and orientation;
  * A genetic algorithm is used to solve the packing problem. 

Figures a-d below show a simulated process of colony growth: \\
{{frep:colony11.gif?nolink}}**a** {{frep:colony21.gif?nolink}}**b**\\
{{frep:colony110.gif?nolink}}**c** {{frep:colony180.gif?nolink}}**d**

[[http://hyperfun.org/colony0.gif|Zoom view]] {{frep:colony0_t.gif?nolink}} of the colony shows irregular shapes of the particles.

Figures e-g below show immortalized human lymphocytes AHH-1 photographed by Polaroid MicroCam camera (x200 magnification) installed on an Olympus CK2 microscope: \\
{{frep:cell1.gif?nolink}}**e** {{frep:cell2.gif|nolink}}**f** {{frep:cell3.gif?nolink}}**g**

The algorithms used in our simulation are discussed in the paper:

Savchenko V.V., A.G.Basnakian , Pasko A.A., S.V.Ten , R.Huang\\
"Simulation of a growing mammalian cell colony: collision-based packing algorithm for deformable particles", Computer Graphics: Developments in Virtual Environments, R.Earnshaw and J.Vince (Eds.), (CG International'95 Conference, Leeds, UK, June 26-30), 1995, Academic Press, pp.437-447. 

V. V. Savchenko, A. G. Basnakian, A. A. Pasko\\ 
"Computer simulation and analysis of a growing mammalian cell colony", Mathematical & Computational Biology: Computational Morphogenesis, Hierarchical Complexity & Digital Evolution, C. L. Nehaniv, Ed., Lectures on Mathematics in Life Sciences Series, Volume 26, American Mathematical Society, Providence, Rhode Island, USA, 1999, pp. 111-120, ISBN: 0-8218-0941-5. [[http://hyperfun.org/wiki/lib/exe/fetch.php?media=colony_lmls99.pdf|PDF]]