Lamellar appearance

Plants were probably the first to have polyester outerwear, as the aerial parts of higher plants are covered with a cuticle whose structural component is a polyester called cutin. Even plants that live under water in the oceans, such as Zoestra marina, are covered with cutin. This lipid-derived polyester covering is unique to plants, as animals use carbohydrate or protein polymers as their outer covering. Cutin, the insoluble cuticular polymer of plants, is composed of inter-esterified hydroxy and hydroxy epoxy fatty acids derived from the common cellular fatty acids and is attached to the outer epidermal layer of cells by a pectinaceous layer (Fig. 1). The insoluble polymer is embedded in a complex mixture of soluble lipids collectively called waxes [1], Electron microscopic examination of the cuticle usually shows an amorphous appearance but in some plants the cuticle has a lamellar appearance (Fig. 2). 

Fig. 4.6 Cellular localization of FAAFI in human keratinocytes. Co-localization of FAAFI with calnexin (marker to endoplasmic reticulum). Human keratinocytes (HaCaT cells) were co-stained with anti-FAAH (in green) and anti-calnexin (in red) antibodies. Superimposition of the two stainings (merge) revealed a vesicular region of the endoplasmic reticulum where FAAH and calnexin largely overlapped (yellow). Dot structures, where FAAH and calnexin co-localized, are indicated by the white arrows in the inset at the bottom of the merge panel. The remaining part of the reticulum, with lamellar appearence, did not display any colocalization of the two proteins. Courtesy of Dr. Sergio Oddi (University of Teramo, Italy)...

CeHulosc.—Cellulose acetate in dilute aqueous solutions has been deacetylated and thus precipitated in order to grow single crystals of cellulose 11. The crystals had a ribbon-like lamellar appearance. Best results were obtained using methylamine as the deac lating agent. 

Suberized layers in plant roots have been ultrastructurally characterized in detail (457). The characteristic lamellar appearance has been observed in the en-dodermal cell walls of the roots of several plants (286, 309, 381, 403, 495). Similarly, suberin layers have been observed in hypodermal and epidermal cells of plant roots (77, 78, 122, 174, 334, 365, 366, 380, 498). Lamellar suberin has also been ultrastructurally characterized at various internal locations in the plant such as the bundle sheath of grasses (51, 118, 173, 331, 332), the chalazal region of the seedcoat (111), and in the cell wall of crystal idioblasts (441, 479, 480) (Fig. 6.4.3). 

Mg yA1 2> or P-(MgAl). Thus aluminum occurs in magnesium alloys both in soHd solution and as the intermediary intermetaUic phase. The latter is clear white and in slight rehef in poHshed and etched samples. In as-cast alloys, the hard phase occurs in massive form, but when precipitated from sohd solution a lamellar stmcture is formed similar to peadite in steel. When produced by aging at low temperatures, it appears as fine particles. 

The second difference is related to the structure of the lamellar phase. The Euler characteristic has been assumed zero in the whole lamellar phase by Gompper and Kraus [47], whereas we show that it fluctuates strongly in the lamellar phase between the transition line and the topological disorder fine. The notion of the topological disorder line has not appeared in their paper. We think that the topological disorder line is much closer to the transition... 

Structured laundry liquids are currently available in Europe and were recently introduced in the United States [50,51]. These products typically contain high levels of surfactants and builder salts, as well as enzymes and other additives. In the presence of high ionic strength, the combination of certain anionic and nonionic surfactants form lamellar liquid crystals. Under the microscope (electron microscope, freeze fracturing) these appear as round droplets with an onion-like, multilayered structure. Formation of these droplets or sperulites permits the incorporation of high levels of surfactants and builders in a pourable liquid form. Stability of the dispersion is enhanced by the addition of polymers that absorb onto the droplet surface to reduce aggregation. 

Copolymers (graft or block) made of immiscible sequences give rise to biphasic morphologies depending on the ratio of immiscible sequences (or of their lengths). Such possible microstructures are reported in Figure 33. A minor phase can be dispersed as nodules (spheres) or filaments (cylinders) while, when concentrations of both phases get similar, lamellar (interpenetrated) structures can appear. It should be noted that rather similar morphologies could also be found in (compatibilised) polymer blends. 

Fig. 8 Various structure parameters appearing in the crystallization process of PET at 80 °C A, characteristic wavelength of SD D, dense domain size L, long period /p, persistence length Dc, lamellar stem length [19]...

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