The combination of ion mobility mass spectrometry studies and theoretical calculations including docking studies permitted a detailed structural description of noncovalent complexes of folic acid (FA) and native cyclodextrins (α-CD, β-CD, and γ-CD). The mode of noncovalent association depended on the cavity size of the cyclodextrin. The structure of FA/α-CD represented the exclusion complex in which the aminobenzoic moiety and the aromatic pteridine ring of folic acid remain outside the cyclodextrin cavity, while the glutamate residue is anchored in the interior of the α-cyclodextrin. A rotaxane-type structure was proposed for the FA/β-CD complex with the aminobenzoic part of FA being trapped in the central cavity of β-CD. The glutamate residue and the aromatic pteridine ring interact with the primary and secondary rim hydroxyl residues, respectively, enhancing complex stability. Two possible structures of FA/γ-CD were suggested, the first one being analogous to the FA/β-CD complex and the second one being more stable-in which the aromatic pteridine ring penetrates into the CD cavity while the glutamate residue with the aminobenzoic part of FA is exposed to the cone exterior of CD at its wider edge. Further insight into the association behavior of the folic acid toward cyclodextrins evaluated by thermodynamic calculations indicates that the process is highly exothermic. The complex stability increased in the order FA/α-CD < FA/β-CD < FA/γ-CD. This order is consistent with the previously determined relative gas-phase stability established based on the dissociation efficiency curves of the FA/CD complexes.
An important role in the extraction and utilisation of siliceous rocks was played by the Udorka Valley region, situated in the south-eastern part of the Ryczów Upland. In this region, numerous outcropsof various siliceous rocks are located including outcrops of chocolate flint, and many sites with artefacts from chocolate flint dated from the Middle Palaeolithic. In Udorka Valley, in the area of chocolate flint outcrop, a number of small depressions in the ground with unfinished flint artefacts were encountered and which have been tentatively considered to be remnants of the activities of prehistoric miners. The area under scrutiny was investigated using airborne laser scanning methods (LiDAR, ALS). This paper presents the preliminary results.
This project aims to reconstruct the settlement patterns and palaeoenvironment of the Saspów Valley in the Polish Jura by combining unpublished archaeological fieldwork with results of recent excavations at 13 cave sites.
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