PATTERN FORMATION IN CHEMOTAXIC REACTION-DIFFUSION SYSTEMS

2012 ◽  
Vol 05 (03) ◽  
pp. 1260013
Author(s):  
HIROTO SHOJI ◽  
KEITARO SAITOH
Keyword(s):  
Free Energy ◽  
Pattern Formation ◽  
Three Dimensional ◽  
Reaction Diffusion ◽  
Two Dimensions ◽  
Two Dimensional ◽  
Volume Filling ◽  
Reaction Diffusion Systems ◽  
Receptor Aggregation ◽  
Diffusion Systems

In this study, we investigate two-dimensional patterns generated by chemotaxis reaction-diffusion systems. We numerically examine the Keller–Segel models with the volume-filling aggregation term and the receptor aggregation term in two dimensions. Spotted, striped and reversed spotted patterns are obtained as stable motionless equilibrium patterns. The relative stability of these patterns is studied numerically on the basis of the derived free energy. The intuitive understanding of these generated patterns and the relation with three-dimensional patterns are also discussed.

Game of Morphogenesis: What Can We Learn from the Pattern-Form Interplay Models?

1998 ◽  
Vol 08 (05) ◽  
pp. 991-1001 ◽  
Author(s):  
A. V. Spirov
Keyword(s):  
Pattern Formation ◽  
Three Dimensional ◽  
Reaction Diffusion ◽  
Surface Geometry ◽  
Parabolic Pdes ◽  
Reaction Diffusion Systems ◽  
Diffusion Systems ◽  
Nonlinear Parabolic Pdes ◽  
Nonlinear Parabolic ◽  
Secondary Bifurcations

We approach the problem of how the information encoded in linear DNA molecule becomes translated into a three-dimensional form from position of Pattern-Form Interplay Models. The characteristic feature of these models is the existence of feedback loops from (bio)chemical pattern formation to modeling embryo form changes. In accordance with the model the system is open and changes in a pattern give rise to changes in form and these changes in form (surface geometry) cause further pattern changes, and so on. Spontaneous pattern formation takes place in the model as primary and secondary bifurcations of nonlinear parabolic PDEs describing reaction-diffusion systems with imposed gradient. We briefly review the main results of previous works and consider the phenomenon of axis tilting as a case of symmetry breaking via secondary bifurcations. The axis tilting bifurcation occurs as a consequence of position-dependency of diffusion coefficients. The explicit demonstration of this phenomenon in Pattern-Form Interplay Models is believed to be new.

SELF-ASSEMBLED SCAFFOLDS USING REACTION–DIFFUSION SYSTEMS: A HYPOTHESIS FOR BONE REGENERATION

2011 ◽  
Vol 11 (01) ◽  
pp. 231-272 ◽  
Author(s):  
DIEGO A. GARZÓN-ALVARADO ◽  
MARCO A. VELASCO ◽  
CARLOS A. NARVÁEZ-TOVAR
Keyword(s):  
Bone Matrix ◽  
Three Dimensional ◽  
Reaction Diffusion ◽  
Tissue Growth ◽  
New Bone Formation ◽  
Reaction Diffusion Systems ◽  
Bone Scaffolds ◽  
Full Control ◽  
Diffusion Systems ◽  
Biomaterial Scaffold

One area of tissue engineering concerns research into alternatives for new bone formation and replacing its function. Scaffolds have been developed to meet this requirement, allowing cell migration, bone tissue growth, transport of growth factors and nutrients, and the improvement of the mechanical properties of bone. Scaffolds are made from different biomaterials and manufactured using several techniques that, in some cases, do not allow full control over the size and orientation of the pores characterizing the scaffold. A novel hypothesis that a reaction–diffusion (RD) system can be used for designing the geometrical specifications of the bone matrix is thus presented here. The hypothesis was evaluated by making simulations in two- and three-dimensional RD systems in conjunction with the biomaterial scaffold. The results showed the methodology's effectiveness in controlling features such as the percentage of porosity, size, orientation, and interconnectivity of pores in an injectable bone matrix produced by the proposed hypothesis.

A New Mechanical Algorithm for Calculating the Amplitude Equation of the Reaction-Diffusion Systems

2011 ◽  
pp. 205-213
Author(s):  
Houye Liu ◽  
Weiming Wang
Keyword(s):  
Hopf Bifurcation ◽  
Pattern Formation ◽  
Normal Form ◽  
Reaction Diffusion ◽  
Amplitude Equation ◽  
Diffusion Reaction ◽  
Future Studies ◽  
Reaction Diffusion Systems ◽  
Diffusion Systems ◽  
Form Approach

Amplitude equation may be used to study pattern formatio. In this chapter, we establish a new mechanical algorithm AE_Hopf for calculating the amplitude equation near Hopf bifurcation based on the method of normal form approach in Maple. The normal form approach needs a large number of variables and intricate calculations. As a result, deriving the amplitude equation from diffusion-reaction is a difficult task. Making use of our mechanical algorithm, we derived the amplitude equations from several biology and physics models. The results indicate that the algorithm is easy to apply and effective. This algorithm may be useful for learning the dynamics of pattern formation of reaction-diffusion systems in future studies.

The Chemical Basis of Morphogenesis (1952)

2004 ◽  
Author(s):  
Alan Turing
Keyword(s):  
Reaction System ◽  
Reaction Diffusion ◽  
Two Dimensions ◽  
Stationary Waves ◽  
Chemical Substances ◽  
Reaction Diffusion Systems ◽  
Diffusion Systems ◽  
Random Disturbances ◽  
Physical Laws ◽  
And Diffusion

It is suggested that a system of chemical substances, called morphogens, reacting together and diffusing through a tissue, is adequate to account for the main phenomena of morphogenesis. Such a system, although it may originally be quite homogenous, may later develop a pattern or structure due to an instability of the homogeneous equilibrium, which is triggered off by random disturbances. Such reaction-diffusion systems are considered in some detail in the case of an isolated ring of cells, a mathematically convenient, though biologically unusual system. The investigation is chiefly concerned with the onset of instability. It is found that there are six essentially different forms which this may take. In the most interesting form stationary waves appear on the ring. It is suggested that this might account, for instance, for the tentacle patterns on Hydra and for whorled leaves. A system of reactions and diffusion on a sphere is also considered. Such a system appears to account for gastrulation. Another reaction system in two dimensions gives rise to patterns reminiscent of dappling. It is also suggested that stationary waves in two dimensions could account for the phenomena of phyllotaxis. The purpose of this paper is to discuss a possible mechanism by which the genes of a zygote may determine the anatomical structure of the resulting organism. The theory does not make any new hypotheses; it merely suggests that certain well-known physical laws are sufficient to account for many of the facts. The full understanding of the paper requires a good knowledge of mathematics, some biology, and some elementary chemistry. Since readers cannot be expected to be experts in all of these subjects, a number of elementary facts are explained, which can be found in text-books, but whose omission would make the paper difficult reading. In this section a mathematical model of the growing embryo will be described. This model will be a simplification and an idealization, and consequently a falsification. It is to be hoped that the features retained for discussion are those of greatest importance in the present state of knowledge. The model takes two slightly different forms. In one of them the cell theory is recognized but the cells are idealized into geometrical points.

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