Origin of macroscopic adhesion in organic light-emitting diodes analyzed at different length scales.

Organic light-emitting diodes (OLEDs) have been widely studied because of their various advantages. OLEDs are multi-layered structures consisting of organic and inorganic materials arranged in a heterojunction; the nature of adhesion at their heterogeneous interfaces has a significant effect on their properties. In this study, the origin of macroscopic adhesion was explored in OLEDs using a combination of microscopy techniques applied at different length scales.

Diesterified nitrone rescues nitroso-redox levels and increases myocyte contraction via increased SR Ca(2+) handling.

Nitric oxide (NO) and superoxide (O(2) (-)) are important cardiac signaling molecules that regulate myocyte contraction. For appropriate regulation, NO and O(2) (.-) must exist at defined levels.

Reactivities of superoxide and hydroperoxyl radicals with disubstituted cyclic nitrones: a DFT study.

The unique ability of nitrone spin traps to detect and characterize transient free radicals by electron paramagnetic resonance (EPR) spectroscopy has fueled the development of new spin traps with improved properties. Among a variety of free radicals in chemical and biological systems, superoxide radical anion (O(2)(•-)) plays a critical role as a precursor to other more oxidizing species such as hydroxyl radical (HO(•)), peroxynitrite (ONOO(-)), and hypochlorous acid (HOCl), and therefore the direct detection of O(2)(•-) is important. To overcome the limitations of conventional cyclic nitrones, that is, poor reactivity with O(2)(•-), instability of the O(2)(•-) adduct, and poor cellular target specificity, synthesis of disubstituted nitrones has become attractive.

Fast reactivity of a cyclic nitrone-calix[4]pyrrole conjugate with superoxide radical anion: theoretical and experimental studies.

Nitrone spin traps have been employed as probes for the identification of transient radical species in chemical and biological systems using electron paramagnetic resonance (EPR) spectroscopy and have exhibited pharmacological activity against oxidative-stress-mediated diseases. Since superoxide radical anion (O2(•-)) is a major precursor to most reactive oxygen species and calix[4]pyrroles have been shown to exhibit high affinity to anions, a cyclic nitrone conjugate of calix[4]pyrrole (CalixMPO) was designed, synthesized, and characterized. Computational studies at the PCM/B3LYP/6-31+G(d,p)//B3LYP/6-31G(d) level suggest a pendant-type linkage between the calix[4]pyrrole and the nitrone to be the most efficient design for spin trapping of O2(•-), giving exoergic reaction enthalpies (ΔH(298K,aq)) and free energies (ΔG(298K,aq)) of -16.