Biomedical Engineering Reference
In-Depth Information
42
32
32
42
24
40
29
24
29
40
16
16
11
19
11
19
21
3
8
34
21
27
3
27
34
8
6
6
13
14
14
13
26
26
5
1
1
22
5
22
18
9
9
18
10
10
31
4
2
4
17
2
31
17
7
23
23
12
7
15
12
15
25
20
25
20
Figure 1.4
Norway Spruce (
Picea abies
): spi-
ral phyllotaxis of needle primordia emerging
from central SAM. The primordial numbers
are in reverse order of their appearance. The
newest primordium initiates at the periphery
of the meristem where there is the largest
free space. As they grow, older primordia are
displaced radially away from the center of
the circular meristem. Then, the older the
primordium, the farther it is from the center.
For example, the contact on the parastichy
spiral with difference 5 (between 8 and 13
spirals) changes after 5-7 flip to the con-
tact on the spiral with difference 21. After
[48]. With kind permission of the author Pau
Atela.
1.1.2.1
Ring-Shaped Grain Boundary
D'Arcy Thompson emphasized the deep correlation between mathematical state-
ments, physical laws, and fundamental phenomena of organic growth of biological
structures. At the end of ''On Growth and Form'' we read: ''
something of the
use and beauty of mathematics I think I am able to understand. I know that in the
study of material things number, order, and position are the threefold clue to exact
knowledge'' [49].
Occurrence of defects begins a process of destruction of a crystal. Destruction is
therefore necessary for the crystal growth, as shown by Rivier and Lissowski [50].
In a similar manner, appearance of one new osteon leads osteon lattice defects to
arise - a pair of pentagon-heptagon (five to seven) dislocations. Hence, the bone
turnover is realized by the defects of osteonic structure, cf. Figures 1.15 and 1.16
of compact bone structure.
In 1868, from his microscopic study of plant meristems, botanist Hofmeister
[51] proposed that a new primordium always forms in the least crowded spot along
the meristem ring, at the periphery of SAM.
In a manner analogous to the propagation of defects during crystallization, the
growth of a tissue stress leads to buckling and undulation down to the order of the
cell diameter. Structural control in tissue development is accomplished by wavelike
5-7 dislocation rearrangement. The oriented cell divisions as 5-7 climbing can
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