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    Phospholipid and triacylglycerol fatty acid composition of major life stages of sunn pest, Eurygaster integriceps (Heteroptera: Scutelleridae)
    (Elsevier Science Inc, 2002) Bashan, M; Akbas, H; Yurdakoc, K
    Phospholipid and triacylglycerol fatty acid compositions of whole animals from all life stages of Eurygaster integriceps, including eggs, nymphs, pre-diapausing adults and diapausing adults, were determined. The fatty acid composition of total lipids of their food, wheat, was also determined. The major components of the insects and their food were the expected C16 and C18 saturated and unsaturated fatty acids. Since fatty acid compositions of third-stadium nymphs were not similar to the profiles of their food, most likely, dietary fatty acids are modified by the insect. The fact is that the food does not provide C20 polyunsaturated fatty acids, but the insect tissue lipids include these components. We suggest biosynthesis of the C20 components by elongation/desaturation of C18:2n-6, an abundant component of the diets. We also show differences in fatty acid profiles from each of the life stages. (C) 2002 Elsevier Science Inc. All rights reserved.
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    Preparation and characterization of polyoxometallates of molybdenum, tungsten and their salts
    (Marcel Dekker Inc, 1997) Akba, O; Guzel, F; Yurdakoc, K; Gumgum, B; Tez, Z
    In this work, confirmation of the molecular formula and investigation of the structural stability of the prepared various types of heteropoly acids and their salts by TGA are reported. Specific surface areas of the samples were determined by the BET-single point N-2 adsorption method. Scanning electron microscopy (SEM) was used for the of surface topography of the samples in the sense of crystalline and amorphous states and the acidities of these solid samples were determined based on the color changes of suitable indicator solutions by the way of a butylamine titration method. Impurities, weight ratios and bonding states of the characteristic elements of the samples were determined from XRD, EDX and FTIR studies.