The Influence of the Aircraft Operating Fluids on the Mechanical Parameters of the Airport Surface Concrete.

The authors of the article assessed the impact of operating fluids used to service aircraft on changing mechanical parameters of cement concrete intended for airport pavement. The research concerned concrete designed with the use of CEM I 42.5N LH NA low-alkali cement, broken granite aggregate, fine washed aggregate, and admixtures.

GC separation of 2-substituted ethyl propionate enantiomers on permethylated and 2,6-dimethyl-3-pentyl beta- and gamma-cyclodextrin stationary phases.

In this work, the capillary gas chromatographic enantiomer separation of eight congeneric compounds with general formulae CH3-HCX-COOC2H5 (where X = Cl, Br, I, CN, OH, OC2H5, OC6H5 and NHCOCF3) on four different permethyl- and 2,6-di-O-methyl-3-O-pentyl- beta- and gamma-CD stationary phases has been studied. The separation of enantiomers was evaluated in terms of the interactions of the X substituent of studied derivatives, as well as the nature of the 3-O-alkyl group in the 2,6-di-O-methyl-3-O-alkyl-CDs and the CDs cavity size. The differences in thermodynamic data [deltaH and -deltaS] obtained for studied compounds and the selectivity of modified beta- and gamma-cyclodextrin phases in gas chromatographic separation were evaluated.

[Certain biochemical markers in women with abnormal states of the reproductive system].

The concentrations of collagen, hydroxyproline, glycosaminoglycans and estradiol were determined in 60 women aged 51 to 60 years (mean: 55.6 +/- 4.4).