Waxes species distribution

Data from one escolar-associated outbreak found no correlation between BMI, age, health status, and amount of fish consumed to the severity and occurrence of symptoms, while other factors, such as variability in wax ester content in different fillet cut depths, could be relevant (Yohannes et al., 2002). Unlike some fish species, such as herring, which have uniform muscle oil content along the body (Brandes and Dietrich, 1953), muscle oil content in escolar and oilfish is not evenly distributed. Bone (1972) found that muscle oil content in oilfish increases from 14.5% (near vertebral column) to 24.7% (near the skin). A similar trend was also observed by Ruiz-Gutierrez et al. (1997) with higher oil content found in subcutaneous muscles than the periosteum. However, the lipid profile for... 

Figure 11.10 shows the molecular weight distribution for the oils and Figure 11.11 for the waxes derived from the fluidized-bed pyrolysis of the plastic mixture in relation to pyrolysis temperature. The oils show a higher proportion of low-molecular-weight species compared with the waxes and a clear bimodal distribution for the oils and waxes. The two peaks occur at molecular weights of about 120 and about 1200 Da., depending on whether... 

As previously mentioned, the triglycerides found in biomass are esters of the triol, glycerol, and fatty acids (Fig. 3.6). These water-insoluble, oil-soluble esters are common in many biomass species, especially the oilseed crops, but the concentrations are small compared to those of the polysaccharides and lignins. Many saturated fatty acids have been identified as constituents of the lipids. Surprisingly, almost all the fatty acids that have been found in natural lipids are straight-chain acids containing an even number of carbon atoms. Most lipids in biomass are esters of two or three fatty acids, the most common of which are lauric (Cn), myristic (Cu), palmitic (Cia), oleic (Cis), and linoleic (Cis) acids. Palmitic acid is of widest occurrence and is the major constituent (35 to 45%) of the fatty acids of palm oil. Lauric acid is the most abundant fatty acid of palm-kemel oil (52%), coconut oil (48%), and babassu nut oil (46%). The monounsaturated oleic acid and polyunsaturated linoleic acid comprise about 90% of sunflower oil fatty acids. Linoleic acid is the dominant fatty acid in com oil (55%), soybean oil (53%), and safflower oil (75%). Saturated fatty acids of 18 or more carbon atoms are widely distributed, but are usually present in biomass only in trace amounts, except in waxes. 

All these lipophilic components perform a function for the living tree. The exact function is not understood for all substances. The composition of the lipophilic wood extractives varies from species to species, and is far from homogeneously distributed in the tree. All woods contain sterols, waxes, glycerides and other aliphatic extractives. However, softwood contains considerable quantities of rosin acids (e.g. abietic acid), but these acids do not exist in hardwood (e.g. birch and aspen). Certain components are predominantly located in the bark of the tree. The sterol fraction from birch and aspen bark comprises almost exclusively beta-sitosterol by way of example. 

Table 4.1. Distribution of uropygial gland wax esters among avian species ...

Branched-chain alkanes are common in cuticular wax although much less widely distributed than n-alkanes. They comprise a major proportion (nearly 50%) of the alkane fraction from some Nicotiana and Geonium species. Generally, the iso- and anteiso-alkanes (cf Table 1) with odd and even numbers of carbon atoms, respectively, are the main examples although compounds with internal and/or multiple methyl branching and even cycloalkanes have been reported as minor components" " . iso-Alkanes with even-carbon numbers (e.g. C32 and C34 compounds) occur in wax from rose and lavender petals, respectively, and iso and anteiso homologues lower than the range listed in Table 4 (e.g. C21-C23 compounds) have been found in lilac blossom. ... 

The most important fundamentals of continuous thermodynamics will be outlined below. Firstly, let us consider a continuous ensemble consisting of a very large number of chemically similar species only differing in the characterization variable M. For example, this can be a polymer, a petroleum fraction or a wax. As characterization variable, the molar mass, the normal boiling-point temperature or the number of carbon atoms may be considered. The extensive distribution function w(M) is defined by... 

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