Thermally activated processes in an organic long-persistent luminescence system.

Glow-in-the-dark materials can store absorbed photon energy and emit light for long periods of time. While inorganic long-persistent luminescence (LPL) materials are crystalline and often require rare metals, organic LPL (OLPL) materials are flexible and require no rare metals. The emission process of OLPL systems consists of photoinduced charge separation, charge accumulation, and emission from charge recombination. Although emission processes of OLPL systems have been investigated, the charge separation and accumulation processes remain enigmatic. In this study, we investigated the charge carrier dynamics of a binary OLPL system comprising of electron donors and acceptors. We confirmed the presence of thermal activation processes, thermally activated delayed fluorescence and thermoluminescence in the OLPL system.

Organic Long-Persistent Luminescence from a Flexible and Transparent Doped Polymer.

Long-persistent luminescence (LPL) materials have a wide range of applications, such as in architectural decorations, safety signs, watch dials, and glow-in-the-dark toys. Present LPL materials based on inorganics must be processed into powders and blended with polymer matrices before use. However, micropowders of inorganic LPL materials show poor compatibility with common polymers, limiting the mechanical properties and transparency of the composites. Here, a polymer-based organic LPL (OLPL) system that is flexible, transparent, and solution processable is reported. Following low-power excitation at room temperature, this polymer-based OLPL system exhibits LPL after phosphorescence from the donor.

Evaluation of dopamine D2/D3 and serotonin 5-HT2A receptor occupancy for a novel antipsychotic, lurasidone, in conscious common marmosets using small-animal positron emission tomography.

RATIONALE: Lurasidone is a novel antipsychotic drug with potent binding affinity for dopamine D(2) and serotonin (5-hydroxytryptamine, 5-HT)(2A), 5-HT(7), and 5-HT(1A) receptors. Previous pharmacological studies have revealed that lurasidone exhibits a preferable profile (potent antipsychotic activity and lower incidence of catalepsy) to other antipsychotic drugs, although the contribution of receptor subtypes to this profile remains unclear. OBJECTIVES: To compare target engagements of lurasidone with those of an atypical antipsychotic, olanzapine, we performed evaluation of dopamine D(2)/D(3) and serotonin 5-HT(2A) receptor occupancy in vivo by positron emission tomography (PET) with conscious common marmosets. METHODS: We measured brain receptor occupancies in conscious common marmosets after oral administrations of lurasidone or olanzapine by PET with [(11)C]raclopride and [(11)C]R-(+)-α-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenylethyl)]-4-piperidine methanol (MDL 100907) for D(2)/D(3) and 5-HT(2A) receptors, respectively. RESULTS: Increases in brain D(2)/D(3) receptor occupancies of both lurasidone and olanzapine, which reached >80 % at maximum, were observed in the striatum with significant correlations to plasma drug levels. However, lurasidone showed lower 5-HT(2A) receptor occupancy in the frontal cortex within the same dose range, while olanzapine showed broadly comparable 5-HT(2A) and D(2)/D(3) receptor occupancies. CONCLUSIONS: Compared with olanzapine, lurasidone preferentially binds to D(2)/D(3) receptors rather than 5-HT(2A) receptors in common marmosets. These results suggest that the contribution of in vivo 5-HT(2A) receptor blocking activity to the pharmacological profile of lurasidone might differ from olanzapine in terms of the low risk of extrapyramidal syndrome and efficacy against negative symptoms.