For colloidal quantum dot light-emitting diodes (QD-LEDs), blue emissive device has always been inferior to green and red counterparts with respect to device efficiency, primarily because blue QDs possess inherently unfavorable energy levels relative to green and red ones, rendering hole injection to blue QDs from neighboring hole transport layer (HTL) inefficient. Herein, unprecedented synthesis of blue CdZnS/ZnS core/shell QDs that exhibit an exceptional photoluminescence (PL) quantum yield of 98%, extraordinarily large size of 11.5 nm with a shell thickness of 2.6 nm, and high stability against a repeated purification process is reported. All-solution-processed, multilayered blue QD-LEDs, consisting of an HTL of poly(9-vinlycarbazole), emissive layer of CdZnS/ZnS QDs, and electron transport layer of ZnO nanoparticles, are fabricated. Our best device displays not only a maximum luminance of 2624 cd/m(2), luminous efficiency of 2.2 cd/A, and external quantum efficiency of 7.1%, but also no red-shift and broadening in electroluminescence (EL) spectra with increasing voltage as well as a spectral match between PL and EL.

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Aging is an inevitable process of life. Defined by progressive physiological and functional loss of tissues and organs, aging increases the risk of mortality for the organism. The aging process is affected by various factors, including genetic and epigenetic ones. Here, we review the chromatin-specific epigenetic changes that occur during normal (chronological) aging and in premature aging diseases. Taking advantage of the reversible nature of epigenetic modifications, we will also discuss possible lifespan expansion strategies through epigenetic modulation, which was considered irreversible until recently.

BackgroundChildren and parents experience significant anxiety and distress during the preoperative period. This is important because preoperative anxiety in children is associated with adverse postoperative outcome. So we suggest behaviorally oriented preoperative anxiety intervention program based on the anesthesia and psychology with smartphone application, world-widely used.MethodsA total 120 patients (aged 1-10 years old) who were scheduled for elective surgery under general anesthesia was included in this randomized controlled trial. We randomized the patients into three groups, with using intravenous (IV) midazolam sedation (M group), with using smartphone application program (S group), and with using low dose IV midazolam plus smartphone application program (SM group). And the child anxiety was assessed using the modified Yale Preoperative Anxiety Scale (mYPAS) at holding area, 5 min after intervention, entrance to operating room.ResultsIn all three groups, mYPAS after intervention were lower than the preoperative holding area (M group 52.8 ± 11.8 vs 41.0 ± 7.0, S group 59.2 ± 17.6 vs 36.4 ± 7.3, SM group 58.3 ± 17.5 vs 26.0 ± 3.4). A comparison of mYPAS scores between each group showed that the S group reduced anxiety lower than M group (P < 0.01), and the SM group exhibited significantly lower anxiety than the two other groups (P < 0.01).ConclusionsThe preoperative preparation program using smartphone application is simple and customized by individual development that effective in the reduction of preoperative anxiety.