The molecular dynamics of a ferroelectric liquid crystal, denoted ZLL 7/*, is investigated by means of (2)H NMR relaxation. The spin-lattice (T(1Q) and T(1Z)) and spin-spin (T(2)) relaxation times of two isotopomers of ZLL 7/*, labeled on the phenyl and biphenyl fragments, are measured and their behavior upon passing from the SmA to the hexatic phase, through the ferroelectric SmC*, antiferroelectric SmC*(A), and re-entrant ferroelectric SmC*(re) phases, is discussed. A comparison between the measured T(2) and T(2)*, directly related to the experimental linewidth, provides information on the heterogeneity of the system, thus allowing confirmation of previous hypotheses concerning the structural and ordering properties of the SmC*(A) and SmC*(re) phases.
View Article and Find Full Text PDFThe ability of some 2-alkyl(aryl)-4,6-dimethoxy-1,3,5-triazine derivatives to interfere with production of reactive oxygen species (ROS) by human phagocytes was evaluated in an in-vitro cell model. Superoxide anion (O(2)(-*)) production by human polymorphonuclear cells (PMNs), challenged by the chemotactic agent N-formylmethionyl-leucyl-phenylalanine (FMLP), was inhibited in a dose-dependent manner by all the compounds tested, compounds 3, 4 and 5 being statistically the most active. Adhesion of PMNs to vascular endothelial cells (ECs) is a critical step in recruitment and infiltration of leucocytes into tissues during inflammation, and the effects of 1,3,5-triazine derivatives on PMN adhesion to ECs from the human umbilical vein (HUVEC) were also investigated.
View Article and Find Full Text PDFThe cytotoxic activities of new 2-alkyl-4,6-dihetero(N,O)alkyl-1,3,5-triazines toward selected tumor cell lines have been evaluated, and for the first time, the potential of 2-alkyl-4,6-dialkoxy-1,3,5-triazines has been shown.
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