pattern formation


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Pattern formation (biology)

The mechanisms that ensure that particular cell types differentiate in the correct location within the embryo and that the layers of cells bend and grow in the correct relative positions. Pattern formation is one of four processes that underlie development, the others being growth, cell diversification, and morphogenesis. See Animal morphogenesis, Cell differentiation, Plant growth

Pattern formation is the creation of a predictable arrangement of cell types in space during embryonic development. The types of patterns of cell types found in animals and plants can be conveniently described as simple or complex. Simple patterns involve the spatial arrangement of identical or equivalent structures such as bristles on the leg of a fly, hairs on a person's head, or leaves on a plant. Such equivalent patterns are thought to be produced by mechanisms that are the same or very similar in the fly and the plant. Complex patterns are those that are made up of parts that are not equivalent to one another. In the vertebrate limb, for example, the structure of the arm is different at each level, with one bone (humerus) in the upper arm, two bones (radius and ulna) in the lower arm, and a complex set of bones making up the wrist and the hand. How are such nonequivalent parts patterned during development? The theoretical framework that allows a basis for understanding how such patterns arise is called positional information. Two stages exist in the positional information framework. First, a cell must become aware of its position within a developing group, or field, of cells. This specification of cellular position requires a mechanism by which each cell within a field can obtain a unique value or address. The second component is the interpretation of the positional address by a cell to manifest a particular cell type by the expression of a particular set of genes. See Developmental biology, Embryonic differentiation

pattern formation

[′pad·ərn fər‚mā·shən]
(embryology)
The embryogenic process in which the spatial differentiation of cells is specified in a structure that initially is largely homogeneous.
References in periodicals archive ?
Pattern formation is of central importance because the great functionality of modern microelectronics has been enabled by the ability to pack large numbers of individual transistors in a unit area of silicon.
Summary: TEHRAN (FNA)- A nearly 100-year-old physics model captures the essential mechanism of pattern formation and geometry of Arctic melt ponds.
Such systems present many common puzzles and challenges, such as jamming followed by catastrophic collapse (e.g., earthquakes, eruptions, landslides), erratic fluctuations (e.g., blood clots and strokes) and pattern formation (e.g., stratified sediments, segregation in powders).
To obtain fine pattern formation as well as high Cu migration, the authors developed positive tone photosensitive polyimide using soft segment in the polyimide with thermal cross linker.
- By using a low temperature sintered silver nano-ink[3] and an SuPR-NaP technique[4] for pattern formation instead of etching, fine wires less than 4 um (2 um - 4 um) can be formed.
[5], who first revealed the mechanism of coffee-ring pattern formation via colloidal droplet evaporation, noted the important role of capillary flow on mass transport caused by uneven evaporation.
Han, "Pattern formation by dewetting of polymer thin film," Progress in Polymer Science, vol.
Initial distribution of an immobile reactive species can affect pattern formation. Then we make some numerical experiments to check out the estimation effective when the system parameters are fixed but the initial values are different.
Turing patterns have been extensively studied from a theoretical point of view and in terms of numerical simulations; models like the Oregonator (Pullela, et al., 2009), cubic autocatalysis (Gray & Scott, 1983; Sel'kov, 1968) cubic autocatalytic reaction (A + 2B [right arrow] 3B and FitzHugh-Nagumo (Murray, 2003a) have proven to be versatile systems for the study of pattern formation. Thus, it has been studied how the morphology of patterns depends on system parameters, such as kinetic constants, feed flows and system temperature (Gray & Scott, 1984, 1983; R.
Histologically granulomas are identified into six or seven types on the basis of cells and tissues architectural pattern formation. These are Tuberculous granulomas, Lepromatous granulomas, Foreign Body granulomas, Necrobiotic granulomas, Suppurative granulomas, Sarcoidal granulomas and Xanthgranulomas/ malakoplakia.
Ordinary glass slides (Thermo Fisher Scientific) were used for examining pattern formation in QELBY- and silica-containing water droplets positioned with a 1-ml latex-free syringe.
In their article "Turing Bifurcation and Pattern Formation of Stochastic Reaction-Diffusion System," the coauthors Q.