RESUMEN
Multiferroic materialsare widely used in microelectronics because they are sensitive to elastic, magnetic, and electric fields and there is an intrinsic coupling between them. In particular, transition metal-doped BaTiO3 is consideredas a viable multiferroic because of the simultaneous presence of ferroelectricity and magnetism.In this work, we study the electrical and thermal properties of Mn-doped BaTiO3 ceramics that can be used for multicaloric applications. We found that Mn doping leads to the broadening and shifting of the phase transition accompanied with simultaneous decrease of latent heat and entropy. Mn doping causes a decrease in the bulk resistivity while contact resistance remains intact. Doped ceramics can withstand high electric fields(up to 40 kV/cm) and exhibit linear I-V characteristics followed by the Schottkylimited current in contrast to earlier observations. As such, these ceramics are promising for multicaloric applications.
RESUMEN
Since ancient times, edible sea cucumbers have been considered a jewel of the seabed and used in Asian folk medicine for stimulation of resistance against different diseases. However, the power of this sea food has not been established on a molecular level. A particular group of triterpene glycosides was found to be characteristic metabolites of the animals, responsible for this biological action. Using one of them, cucumarioside A2-2 (CA2-2) from the edible Cucumaria japonica species as an example as well as inhibitory analysis, patch-clamp on single macrophages, small interfering RNA technique, immunoblotting, SPR analysis, computer modeling and other methods, we demonstrate low doses of CA2-2 specifically to interact with P2X receptors (predominantly P2X4) on membranes of mature macrophages, enhancing the reversible ATP-dependent Ca2+ intake and recovering Ca2+ transport at inactivation of these receptors. As result, interaction of glycosides of this type with P2X receptors leads to activation of cellular immunity.
Asunto(s)
Cucumaria/química , Glicósidos/farmacología , Macrófagos/metabolismo , Receptores Purinérgicos P2X/metabolismo , Adenosina Trifosfato/química , Animales , Sitios de Unión , Calcio/química , Macrófagos/efectos de los fármacos , Ratones , Ratones Endogámicos BALB C , Conformación Molecular , Técnicas de Placa-Clamp , ARN Interferente Pequeño/metabolismo , Saponinas/farmacología , Resonancia por Plasmón de Superficie , Triterpenos/farmacologíaRESUMEN
Urupocidins A and B (1 and 2), bisguanidine alkaloids with an unprecedented skeleton system, derived from polyketide precursors and containing an unusual N-alkyl-N-hydroxyguanidine moiety, have been isolated from the sponge Monanhora pulchra. The structures of 1 and 2, including absolute configuration, were established using the detailed analysis of 1D and 2D NMR, CD, and mass spectra as well as chemical transformations. Compound 1 increases nitric oxide production in murine macrophages via inducing iNOS expression.
