Visualization of Glutamate Decarboxylase Activity in Barley Seeds under Salinity Stress Using Mass Microscope

γ-Aminobutyric acid (GABA) accumulates in plants in response to environmental stresses. The activity levels of glutamate decarboxylase (GAD), an enzyme involved in GABA biosynthesis, are reported to increase during germination under salinity stress. However, it is not clear which tissues of the plant seeds are affected by GAD activity in response to salinity stress. In this study, the effects of salinity stress on the distribution of barley seeds GAD activity during germination were investigated. The mass spectrometry imaging (MSI) method was optimized, and the distribution of GAD activity in germinated seeds exposed to salinity stress at different germination stages from 12 to 48 h after imbibition was investigated. In this study, MSI was successfully applied to enzyme histochemistry to visualize the relative GAD activity in germinating barley seeds for the first time. The salinity stress increased the GAD activity, mostly due to the increase in relative GAD activity in the embryo. Higher GAD activity was detected in seeds exposed to salinity stress in the scutellum or aleurone layer, which are difficult to separate for extraction. This method can be used to clarify the role of GABA shunts, including GAD enzyme responses, in barley seeds under stress

5,9-Dioxa-13b-Oxophosphanaphtho[3,2,1-<i>de</i>]anthracenes Prepared by Tandem Phospha-Friedel–Crafts Reaction as Hole-/Exciton-Blocking Materials for OLEDs

We report a short synthesis of phosphorus-fused triarylphosphine oxides, 5,9-dioxa-13b-oxophosphanaphtho­[3,2,1-<i>de</i>]­anthracenes (DOPNAs), based on a tandem phospha-Friedel–Crafts reaction. Phosphorescence, UV–visible absorption, and photoelectron yield spectroscopy of vacuum-deposited thin films revealed that the triplet energies, optical band gaps, and ionization potentials of these materials were sufficiently large for them to be utilized in organic light-emitting diodes (OLEDs). Therefore, we fabricated a set of phosphorescent OLEDs based on the above phosphine oxides, confirming that the utilization of these compounds as hole-/exciton-blocking materials significantly improved OLED efficiencies and lifetimes

Reconstruction of the House of Culture

Josiek, Miriam - příjmení z předávacího seznamuPrezenční226 - Katedra architekturyvelmi dobř

Triplet-Energy Control of Polycyclic Aromatic Hydrocarbons by BN Replacement: Development of Ambipolar Host Materials for Phosphorescent Organic Light-Emitting Diodes

In this work, we achieved the triplet-energy control of polycyclic aromatic hydrocarbons (PAHs) by replacing the Carbon−Carbon (CC) unit with a Boron−Nitrogen (BN) unit. Time-dependent density functional theory calculations suggested that the insertion of the BN unit may cause localization of the singly occupied molecular orbitals 1 and 2 (SOMO1/SOMO2) in the triplet state, which in turn can reduce the exchange interaction and dramatically increase the high singlet–triplet excitation energy (<i>E</i>_T). The PAH containing the BN unit, 4b-aza-12b-boradibenzo­[<i>g</i>,<i>p</i>]­chrysene, showed a large <i>E</i>_T value and ambipolar carrier-transport abilities. The introduction of a phenyl substituent on 4b-aza-12b-boradibenzo­[<i>g</i>,<i>p</i>]­chrysene slightly reduced the <i>E</i>_T values and the carrier-transport abilities, but increased the glass-transition temperatures. On the basis of these findings, we successfully built phosphorescent organic light-emitting diodes using the BN compounds as host materials, which exhibit a superior performance over the device using a representative host material, 4,4′-bis­(<i>N</i>-carbazolyl)-1,1′-biphenyl, not only in terms of efficiency but also in terms of device lifetime. This study demonstrated the potential of BN-embedded polycyclic aromatics in organic electronics and showed a novel strategy to achieve triplet-energy control of aromatic compounds