Walls textures

IG Jolliffe, JM Newton. The effect of dosator nozzle wall texture on capsule filling with the mG2 simulator. J Pharm Pharmacol 35 7-11, 1983. 

SB Tan, JM Newton. Influence of capsule dosator wall texture and powder properties on the angle of wall friction and powder-wall adhesion. Int J Pharm 64 227-234, 1990. 

SB Tan, JM Newton. Capsule filling performance of powders with dosator nozzles of different wall texture. Int J Pharm 66 207-211, 1990. 

Under low power SEM (second row in the plates) the various tests appear similar to one another. The principle features of the wall textures of the various species can be observed in all specimens, such as the porous nature of the wall and some surface ornamentation such as inter-pore ridges and muricae. However the partially peeled surface of the final chamber of Subbotina linaperta from ODP Site 689 is apparent through the loss of cancellation on the test surface (Fig. le) and it is also possible to see the trace of a broken final chamber on the specimen from Hampden Beach... 

Hemeeben, C. Olsson, R. K. 2006. Wall textures of Eocene planktonic foraminifera. In PEARSON, P. N. ET AL. (eds) Atlas of Eocene Planktonic Foraminifera. Cushman Foundation Special Pubhcation,... 

The detailed texture of the fibre has been a point of some recent discussion. The cell wall textures are known as axial, transverse, crossed helicoidal and random (Figure 12.7). 

S. Lepxjratti, Andreas Voigt, Rita Mitlohner, Gleb Sukhorukov, Edwin Donath and Helmuth Moehwald., Scanning Force Microscopy Investigation of Polyelectrolyte Nano- and Microcapsule Wall Texture, Langmuir, 16(9), 4059-4063 (2000). 

HOW CELLULOSE SYNTHASE DENSITY IN THE PLASMA MEMBRANE MAY DICTATE CELL WALL TEXTURE... 

Cellulose microfibrils are deposited by cellulose synthases into the cell wall in often strikingly regular patterns. Here we discuss several mechanisms that have been put forward to explain the alignment of cellulose microfibrils that gives rise to ordered cell wall textures the hypothesis that cortical microtubules align cellulose microfibrils during their deposition, the liquid crystal hypothesis in which cellulose microfibrils self-assemble into textures after their deposition, the templated incorporation hypothesis, and the geometrical theory in which the density of active cellulose synthase complexes inside the plasma membrane may dictate the architecture of the cell wall. 

The cell wall texture is a composite of cellulose microfibrils (CMFs) arranged in one CMF thick lamellae. The orientation of the CMFs within a lamella is constant, but may vary from lamella to lamella. The most striking texture is the helicoidal wall, which consists of subsequent lamellae in which the orientation of the CMFs... 

We have formulated a geometrical, mathematical theory for CMF ordering during their deposition, which allows production of axial, helical, crossed, helicoidal, and random wall textures (Emons 1994 Emons and Kieft 1994 Emons and Mulder 1997 1998 2000 2001 2001 Emons et al. 2002 Mulder et al. 2004). Before reviewing our theory, we first discuss the most important alternate CMF ordering hypotheses that have been proposed (1) microtubule-directed CMF orientation, (2) self-assembly like liquid crystals, (3) templated incorporation hypothesis. In addition, we will respond to criticism that has been put forward against the geometrical theory and discuss those predictions from the theory that can be tested experimentally and, therefore, potentially, verify or falsify the theory. 

In 1962, Green stated that ...the control of the cylindrical cell form in plants appears to reside in the orientation of the reinforcing CMFs in the side walls... and that ...control of new synthesis of oriented wall texture is shown to be in... 

Figure 11 -2. Different cell wall textures as predicted by the geometrical model. The ribbons shown represent the tracks of CMFs, obtained from the explicit solutions to the CMF evolution equation, (a) The helicoidal texture in which the angle of orientation between subsequent lamellae changes by a constant amount, (b) A crossed polylamel-late texture with alternate lamellae with transverse and axial oriented CMFs. (c) A purely axial texture, (d) A helical texture in which the CMFs have an almost constant winding angle See Color Plate of this figure beginning on page 355)...

Another problem one could have with the geometrical model is that it would not be able to account for local differences in texture in different faces of the same cell, as are seen in epidermal cells of leaves. However there is no reason to suppose that a cell would not be able to regulate the cellulose to matrix ratio and, therefore, its wall texture in different wall facets. 

The geometrical theory predicts definite effects on the CMF angle and hence on the resultant wall texture following changes in the amount of active synthases (N), the cellulose to matrix ratio (d) and cell geometry (D). The amount of active synthases, moreover, is determined in a definite fashion by the intrinsic parameters of the model shown in Table 11-1 the length of the CSAD, the speed of movement of CSAD, the cellulose synthase lifetime and synthase production curve shape. To verify, falsify, or improve the model we should measure these parameters and relate them to the types of textures formed. 

PAINT THE PATCH. Cover the patching compound with paint that matches the surrounding wall. If the wall is textured, spray it with wall texture spray to match, let dry overnight, and then paint. 

Leporatti, S., Voigt, A., Mitlohner, R., Sukhorukov, G., Donath, E., Mohwald, H. Scanning force microscopy investigation of polyelectrolyte nano- and microcapsule wall texture. Langmuir, 2000,16,4059-4063. 

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