Graphene-based carbon nanostructures with nanometer dimensions have been of great interest due to the existence of a bandgap. So far, well-ordered edge structure and uniformly synthesized graphene quantum dots (GQDs) with a hexagonal single-crystalline structure have not been directly observed owing to the limited precision of current synthesis approaches. Herein, we report on a novel approach not just for the synthesis of the size-controlled single-crystalline GQDs with hexagonal shape but also for a new discovery on constructing 2D and 3D graphene single crystal structures from d-glucose via catalytic solution chemistry. With size-controlled single-crystalline GQDs, we elucidated the crucial role of edge states on luminescence from the correlation between their crystalline size and exciton lifetime. Furthermore, blue-emissive single-crystalline GQDs were used as an emitter on light-emitting diodes and exhibit stable deep-blue emission regardless of the voltage and doping level.

PurposeIncomplete Kawasaki disease (KD) is frequently associated with delayed diagnosis and treatment. Delayed diagnosis leads to increasing risk of coronary artery aneurysm. Anterior uveitis is an important ocular sign of KD. The purpose of this study was to assess differences in laboratory findings, including echocardiographic measurements, clinical characteristics such as fever duration and treatment responses between KD patients with and those without uveitis.MethodsWe conducted a prospective study with 110 KD patients from January 2008 to June 2013. The study group (n=32, KD with uveitis) was compared with the control group (n=78, KD without uveitis). Laboratory data were obtained from each patient including complete blood count (CBC), erythrocyte sedimentation rate (ESR), platelet count, and level of alanine aminotransferase, aspartate aminotransferase, serum total protein, albumin, C-reactive protein (CRP), and N-terminal probrain natriuretic peptide (NT-pro BNP). Echocardiographic measurements and intravenous immunoglobulin responses were compared between the two groups.ResultsThe incidence of uveitis was 29.0%. Neutrophil counts and patient age were higher in the uveitis group than in the control group. ESR and CRP level were slightly increased in the uveitis group compared with the control group, but the difference between the two groups was not significant. No significant differences in coronary arterial complication and treatment responses were observed between the two groups.ConclusionUveitis is an important ocular sign in the diagnosis of incomplete KD. It is significantly associated with patient age and neutrophil count.

Simple but exceptionally efficient 4-diphenylaminocarbazole host material, 4-DPACz, is presented and compared with its positional isomer, 1-DPACz. The shift of diphenylamino substituent from the 1-position to 4-position of carbazole resulted in an increase in the HOMO energy level as well as an increase in triplet energy level. Having a high triplet energy level (2.76 eV) and well-matched HOMO energy level (-5.61 eV), 4-DPACz showed reduced driving voltage and higher efficiencies for solution-processed green PhOLEDs compated to PVK as well as 1-DPACz. Maximum luminous, power, and external quantum efficiencies reaching to 47.9 cd A, 25.2 lm W, and 14.3%, respectively, were achieved with a device configuration of [ITO/PEDOT:PSS/4-DPACz:Ir(mppy)/TPBi/CsF/Al]. Additional enhancement of efficiencies of 4-DPACz was verified when incorporating another dopant, Ir(Si-bppy)(acac), resulting in 59.1 cd A, 29.5 lm W, and 15.8%. Furthermore, reduced efficiency roll-off was clearly observed for 4-DPACz compared with PVK. Such improved device characteristics of 4-DPACz were attributed to its high hole mobility and charge balance inside the emitting layer therof. The excellent results using such a simple-structured 4-DPACz could promote various applications of this 4-DPACz unit as a building block structure for further possible oligomeric, dendritic, and polymeric materials.

ObjectiveIt was proposed that the ability to recognize facial emotions is closely related to complex neurocognitive processes and/or skills related to theory of mind (ToM). This study examines whether ToM skills mediate the relationship between higher neurocognitive functions, such as reasoning ability, and facial emotion recognition.MethodsA total of 200 healthy subjects (101 males, 99 females) were recruited. Facial emotion recognition was measured through the use of 64 facial emotional stimuli that were selected from photographs from the Korean Facial Expressions of Emotion (KOFEE). Participants were requested to complete the Theory of Mind Picture Stories task and Standard Progressive Matrices (SPM).ResultsMultiple regression analysis showed that the SPM score (t=3.19, p=0.002, β=0.22) and the overall ToM score (t=2.56, p=0.011, β=0.18) were primarily associated with a total hit rate (%) of the emotion recognition task. Hierarchical regression analysis through a three-step mediation model showed that ToM may partially mediate the relationship between SPM and performance on facial emotion recognition.ConclusionThese findings imply that higher neurocognitive functioning, inclusive of reasoning, may not only directly contribute towards facial emotion recognition but also influence ToM, which in turn, influences facial emotion recognition. These findings are particularly true for healthy young people.