The effect of instructions on postural-suprapostural interactions in three working memory tasks.

Examining postural control while simultaneously performing a cognitive, or suprapostural task, has shown a fairly consistent trend of improving postural control in young healthy adults and provides insight into postural control mechanisms used in everyday life. However, the role of attention driven by explicit verbal instructions while dual-tasking is less understood. Therefore, the purpose of this investigation is to determine the effects of explicit verbal instructions on the postural-suprapostural interactions among various domains of working memory.

Study of the mechanism of thermal chemical processes in the crystals of YAF tripeptides by means of mass spectrometry and solid state NMR.

Thermal reactions in two Tyr-Ala-Phe (YAF) tripeptide crystals with different molecular packing (monoclinic and hexagonal), distinct stereochemistry of central amino acid (D or L alanine) and specific arrangement of molecules in the crystal lattice (head-to-tail) were investigated. Samples were heated up to 180 °C, while the melting point for YAF crystals is above the 220 °C. Below the melting temperature, in both cases the chemical reactions leading to formation of cyclic dipeptides (YA diketopiperazine) and leaving of phenylalanine were observed.

Differentiation of diastereoisomers of protected 1,2-diaminoalkylphosphonic acids by EI mass spectrometry and density functional theory.

Electron ionization mass spectrometry and density functional theory (DFT) calculations have been used to study the fragmentation of diastereoisomers of protected 1,2-diaminoalkylphosphonic acids. The loss of a diethoxyphosphoryl group and the elimination of diethyl phosphonate were found to be competitive fragmentation processes, which can be used to differentiate both stereoisomers. Selective deuterated analogs and product- and precursor-ion mass spectra allowed the elucidation of the fragmentation mechanisms.

Stereochemical effects in fragmentation of diastereoisomers of protected diethyl 1,2-diamino-alkylphosphonates.

Diastereoisomers of diethyl 5-substituted (2-thioxo-imidazolidin-4-yl)phosphonates, which can be regarded as protected diethyl 1,2-diaminoalkylphosphonates, have been analyzed by electron ionization mass spectrometry. Significant differences in the fragmentation of cis- and trans-diastereoisomers were found. The stereospecificity of the elimination of diethyl phosphonate and the loss of the diethoxyphosphoryl group were studied using specific labeled compounds and collision-induced dissociation.