Correlation of Educational Material Ontology with the Individual Knowledge Structure of Students

In this paper we experimentally study the influence of the storage structure of the educational material, in particular ontologies, on the effectiveness of its use for students that have various levels of skills. The foreign language is used as a subject domain. The results of the research show that ontological structures are effective for storing the teaching material, but they must be transformable, in order not to cause the conflict with the already̵̵existing̵̵individual̵̵knowledge̵̵structure̵̵of̵̵the̵̵students

Synthesis, Structure, and Characterization of Chromo(fluoro)ionophores with Cation-Triggered Emission Based on <i>N</i>‑Methylaza-Crown-Ether Styryl Dyes

Novel 2-benzothiazole-, 4-pyridine-, and 2- and 4-quinoline-based styryl dyes containing an <i>N</i>-methylbenzoaza-15­(18)-crown-5­(6)-ether moiety were synthesized. A detailed electronic spectroscopy study revealed high performance of these compounds as optical molecular sensors for alkali and alkaline-earth metal cations. They were shown to considerably surpass analogous chromoionophores based on <i>N</i>-phenylaza-crown ethers regarding both the ionochromism and the cation-binding ability. In addition, they act as fluorescent sensors for the metal cations by demonstrating cation-triggered emission. Upon complexation with Ba²⁺, the fluorescence enhancement factor reaches 61. The structural features of dyes and their metal complexes were studied by NMR spectroscopy and X-ray diffraction. The high degree of macrocycle preorganization was found to be one of the factors determining the high cation-binding ability of the sensor molecules based on <i>N</i>-methylbenzoaza-crown ethers