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.

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PurposeHigh-functioning autism spectrum disorder (ASD) involves pragmatic impairment of language skills. Among numerous tasks for assessing pragmatic linguistic skills, idioms are important to evaluating high-functioning ASD. Nevertheless, no assessment tool has been developed with specific consideration of Korean culture. Therefore, we designed the Korean Autism Social Language Task (KASLAT) to test idiom comprehension in ASD. The aim of the current study was to introduce this novel psychological tool and evaluate idiom comprehension deficits in high-functioning ASD.Materials and MethodsThe participants included 42 children, ages 6-11 years, who visited our child psychiatric clinic between April 2014 and May 2015. The ASD group comprised 16 children; the attention deficit hyperactivity disorder (ADHD) group consisted of 16 children. An additional 10 normal control children who had not been diagnosed with either disorder participated in this study. Idiom comprehension ability was assessed in these three groups using the KASLAT.ResultsBoth ASD and ADHD groups had significantly lower scores on the matched and mismatched tasks, compared to the normal control children (matched tasks mean score: ASD 11.56, ADHD 11.56, normal control 14.30; mismatched tasks mean score: ASD 6.50, ADHD 4.31, normal control 11.30). However, no significant differences were found in scores of KASLAT between the ADHD and ASD groups.ConclusionThese findings suggest that children with ASD exhibit greater impairment in idiom comprehension, compared to normal control children. The KASLAT may be useful in evaluating idiom comprehension ability.

PurposeAutism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social communication impairments and repetitive behaviors or restricted interests. Impaired pragmatic language comprehension is a universal feature in individuals with ASD. However, the underlying neural basis of pragmatic language is poorly understood. In the present study, we examined neural activation patterns associated with impaired pragmatic language comprehension in ASD, compared to typically developing children (TDC).Materials and MethodsFunctional magnetic resonance imaging (fMRI) was applied to 15 children with ASD and 18 TDC using the Korean pragmatic language task.ResultsChildren with ASD were less accurate than TDC at comprehending idioms, particularly when they were required to interpret idioms with mismatched images (mismatched condition). Children with ASD also showed different patterns of neural activity than TDC in all three conditions (neutral, matched, and mismatched). Specifically, children with ASD showed decreased activation in the right inferior frontal gyrus (IFG) (Brodmann area 47) in the mismatched condition, compared with TDC (IFG; t(31)=3.17, p<0.001).ConclusionThese results suggest that children with ASD face difficulties in comprehending pragmatic expressions and apply different pragmatic language processes at the neural level.

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