Thermal degradation of natural and treated hemp hurds under air and nitrogen atmosphere

Sustainability goals are essential driving principles for the development of innovative materials in the construction industry. Natural fibers represent an attractive alternative as reinforcing material due to good mechanical properties and sustainability prerequisites. The study has been focused on the comparative investigation of chemical and physical treatments of hemp hurds and their influence on the thermal behavior of main hemp constituents in air and nitrogen atmosphere. Thermal decomposition of hemp hurds involves several parallel reactions related to heat and mass transfer processes. A comparison of DSC and TG/DTG results of hemp hurds samples before and after treatments demonstrates a better thermal stability for treated samples. It is caused by changes in chemical composition due to a partial removal of non-cellulosic components from hemp hurds structure, an increase in cellulose content and decrease in its degree of polymerization. The results show different thermal behavior of the hurds samples heated under nitrogen and air atmosphere. Based on DTG records, several-stage process of mass loss has been found for the samples under air, whereas only two-stage process under nitrogen.

     

8-Hydroxyquinoline as a building block for artificial receptors: binding preferences in the recognition of glycopyranosides

8-Hydroxyquinoline-based receptors 1-3, containing a trisubstituted triethylbenzene core, were prepared and their binding properties towards glycosides were evaluated. (1)H NMR and fluorescence titrations as well as binding studies in two-phase systems, such as dissolution of solid carbohydrates in apolar media and phase transfer of sugars from aqueous into organic solvents, revealed β- vs.α-anomer binding preferences in the recognition of glycosides. Compared to the previously described three-armed aminopyridine-based receptor, compounds 1 and 2 showed significantly increased affinity to β-galactoside. Receptor 2, incorporating two 8-hydroxyquinoline units, was shown to be the most effective receptor for β-galactoside. Compound 3, bearing one 8-hydroxyquinoline group, was found to be a highly effective receptor for β-glucoside and shown to be a more powerful receptor than the quinoline-based compound 4, indicating an important role of the quinoline hydroxy group in the complex formation.     

Discovery of novel selective serotonin reuptake inhibitors through development of a protein-based pharmacophore

The serotonin transporter (SERT), a member of the neurotransmitter sodium symporter (NSS) family, is responsible for the reuptake of serotonin from the synaptic cleft to maintain neurotransmitter homeostasis. SERT is established as an important target in the treatment of anxiety and depression. Because a high-resolution crystal structure is not available, a computational model of SERT was built based upon the X-ray coordinates of the leucine transporter LeuT, a bacterial NSS homologue. The model was used to develop the first SERT structure-based pharmacophore. Virtual screening (VS) of a small molecule structural library using the generated SERT computational model yielded candidate ligands of diverse scaffolds. Pharmacological analysis of the VS hits identified two SERT-selective compounds, potential lead compounds for further SERT-related medication development.