Se Hyun Kim

Yeungnam University, Onyang, South Chungcheong, South Korea

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Publications (129)496.14 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Organic field-effect transistors (OFETs) that operated with good electrical stability were prepared by synthesizing fluorinated polyimide (PI) gate dielectrics based on 6FDA-PDA-PDA PI and 6FDA-CF3Bz-PDA PI. 6FDA-PDA-PDA PI and 6FDA-CF3Bz-PDA PI contain 6 and 18 fluorine atoms per repeat unit, respectively. These fluorinated polymers provided smooth surface topographies and surface energies that decreased as the number of fluorine atoms in the polymer backbone increased. These properties led to a better crystalline morphology in the semiconductor film grown over their surfaces. The number of fluorine atoms in the PI backbone increased, the field-effect mobility improved, and the threshold voltage shifted toward positive values (from -0.38 to +2.21 V) in the OFETs with pentacene and triethylsilylethynyl anthradithiophene. In addition, the highly fluorinated polyimide dielectric showed negligible hysteresis and a notable gate bias stability under both a N2 environment and ambient air.
    ACS Applied Materials & Interfaces 08/2014; · 5.01 Impact Factor
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    ABSTRACT: We report herein that a mixed layer of the electron-donating copper phthalocyanine (CuPc) and electron-accepting N,N-ditridecyl perylene diimide (PTCDI-C13) can be an efficient hole injection layer (HIL) for highperformance organic light-emitting diodes (OLEDs). From photophysical, morphological, and structural studies combined with electrical analysis based on the Mott–Schottky model, we conclude that the excellent miscibility between CuPc and PTCDI-C13 enables highly efficient charge transfer, and thus effective p-doping of CuPc, leading to increased hole conductivity of the HIL. As a result, turn-on voltages as low as 2.45 V and greatly improved thermal stabilities as compared to those of OLEDs with conventional CuPc HILs are observed.
    Science of Advanced Materials 08/2014; 6(8). · 2.51 Impact Factor
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    ABSTRACT: The evidence of the association between depression and metabolic syndrome is increasing, but the existence of sex differences in this association remains controversial. The aim of this study was to investigate the association between subjective depressive symptoms and metabolic syndrome and each of its components by sex in the Korean population.
    Progress in Neuro-Psychopharmacology and Biological Psychiatry 06/2014; · 3.55 Impact Factor
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    ABSTRACT: Printed low-voltage complementary inverters based on electrolyte gated transistors are demonstrated. The printed complementary inverters showed gain of 18 and power dissipation below 10 nW. 5-stage ring oscillators operate at 2 V with an oscillation frequency of 2.2 kHz, corresponding to stage delays of less than 50 μs. The printed circuits exhibit good stability under continuous dynamic operation.
    Advanced Materials 06/2014; · 14.83 Impact Factor
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    ABSTRACT: Increased levels of alanine aminotransferase (ALT) are a biomarker for metabolic syndrome (MetS), but this relationship remains unproven in patients with schizophrenia. We assessed the relationship between aminotransferase levels and MetS in patients with schizophrenia. This pooled analysis from two open-label prospective studies included 342 patients with schizophrenia who did not meet criteria for MetS at baseline. The development of MetS was assessed at weeks 12 and 24. MetS developed in 19.1 % of patients during the 24-week follow-up period. ALT levels were significantly associated with incident MetS: for each sex-specific standard deviation increase in log ALT, the odds ratio (OR) of MetS was 1.357 (p = .006) after adjusting for age, sex, duration of illness, smoking, and previous use of antipsychotics. This result remained significant after adjusting for interim weight changes. Compared with patients in the lowest quartile, the OR of MetS in those in the highest quartile within the normal range of ALT levels was 4.276 (p = .024). However, this association was significant only in male patients. Using a cutoff value of 23.0 U/L, sensitivity and specificity were 70.6 and 68.3 %, respectively, in male patients whose ALT levels were in the normal range. A prospective association between ALT levels and MetS highlights the value of ALT levels, even mild ALT elevations within the normal range, as a predictor of the MetS risk in male patients. Baseline liver function tests and monitoring should be obtained during antipsychotic treatment to identify the risk for MetS.
    Psychopharmacology 05/2014; · 4.06 Impact Factor
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    ABSTRACT: Organic electronic devices require a passivation layer that protects the active layers from moisture and oxygen because most organic materials are very sensitive to such gases. Passivation films for the encapsulation of organic electronic devices need excellent stability and mechanical properties. Although Al2O3 films obtained with plasma enhanced atomic layer deposition (PEALD) have been tested as passivation layers because of their excellent gas barrier properties, amorphous Al2O3 films are significantly corroded by water. In this study, we examined the deformation of PEALD Al2O3 films when immersed in water, and attempted to fabricate a corrosion-resistant passivation film by using a PEALD-based Al2O3/TiO2 nano-lamination (NL) technique. Our Al2O3/TiO2 NL films were found to exhibit excellent water anti-corrosion and low gas permeation and require only low-temperature processing (< 100°C). Organic thin film transistors with excellent air-stability (52 days under high humidity (a relative humidity of 90% and a temperature of 38°C)) air were fabricated.
    ACS Applied Materials & Interfaces 04/2014; · 5.01 Impact Factor
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    ABSTRACT: We investigated possible association between depressive disorders and BDNF Val66Met and 5-HTTLPR. Brain derived neurotrophic factor (BDNF) gene and serotonin transporter (SLC6A4) gene are promising candidate genes for depressive disorders. It has been suggested that BDNF promotes the survival and differentiation of serotonergic neurons and that serotonergic transmission exerts powerful control over BDNF gene expression.
    Psychiatry investigation 04/2014; 11(2):192-9. · 1.06 Impact Factor
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    ABSTRACT: The enzymatic activity of histone deacetylases (HDACs) leads to a histone deacetylation-mediated condensed chromatic structure, resulting in transcriptional repression, which has been implicated in the modifications of neural circuits and behaviors. Repeated treatment with electroconvulsive seizure (ECS) induces changes in histone acetylation, expression of various genes, and intrabrain cellular changes, including neurogenesis. In this study, we examined the effects of repeated ECS on the expression of class I HDACs and related changes in histone modifications and gene expression in the rat frontal cortex. Ten days of repeated ECS treatments (E10X) up-regulated HDAC2 expression at the mRNA and protein levels in the rat frontal cortex compared with sham-treated controls; this was evident in the nuclei of neuronal cells in the prefrontal, cingulate, orbital, and insular cortices. Among the known HDAC2 target genes, mRNA expression of N-methyl-d-aspartate (NMDA) receptor signaling-related genes, including early growth response-1 (Egr1), c-Fos, glutamate receptor, ionotropic, N-methyl d-aspartate 2A (Nr2a), Nr2b, neuritin1 (Nrn1), and calcium/calmodulin-dependent protein kinase II alpha (Camk2α), were decreased, and the histone acetylation of H3 and/or H4 proteins was also reduced by E10X. Chromatin immunoprecipitation analysis revealed that HDAC2 occupancy in the promoters of down-regulated genes was increased significantly. Moreover, administration of sodium butyrate, a HDAC inhibitor, during the course of E10X ameliorated the ECS-induced down-regulation of genes in the rat frontal cortex. These findings suggest that induction of HDAC2 by repeated ECS treatment could play an important role in the down-regulation of NMDA receptor signaling-related genes in the rat frontal cortex through histone modification.
    The International Journal of Neuropsychopharmacology 03/2014; · 5.64 Impact Factor
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    ABSTRACT: This study was aimed at investigating or designed to investigate long-term clinical outcomes of risperidone long-acting injectable (RLAI) in patients with schizophrenia or schizoaffective disorder. An open-label, 48-week, prospective study of RLAI treatment was carried out at 63 centers in South Korea. Initial and maintenance dosage of RLAI were adjusted according to clinical judgment. Efficacy was measured by the remission rate, continuation rate, and changes in the clinical measurements such as eight items of the Positive and Negative Symptom Scale (PANSS), the Clinical Global Impression - Severity, and the Schizophrenia Quality of Life Scale. In terms of the safety, Simpson-Angus rating Scale, adverse events (AEs), and BMI were investigated. Of the 522 patients who were enrolled, 472 patients who had been assessed on the eight items of PANSS at baseline and at least once during RLAI treatment were included in the intention-to-treat (ITT) population. The per-protocol (PP) population included 184 patients (39.0%), who completed all assessments during 48 weeks of the follow-up period. Total scores of eight items of PANSS, Clinical Global Impression - Severity, and Schizophrenia Quality of Life Scale were reduced significantly from baseline to endpoint in both ITT and PP populations. The mean dose (SD) of RLAI was 33.2 (7.6) mg. In the PP population, the number of patients who scored 1-3 on eight items of PANSS were 47 (25.5%) at baseline and 144 (78.3%) at 48 weeks. According to the remission defining as scores 1-3 on eight items of PANSS sustaining of at least 6 months' duration by Andreasen, the numbers of patients who achieved remission were 45 (24.5%) at 24 weeks and 120 (65.2%) at 48 weeks. A significant decrease in the mean score of Simpson-Angus rating Scale and a significant increase in BMI over time in last observation carried forward were observed, and patients who fulfilled the remission criteria during the study showed more weight gain than those who did not. During the study period, a total of 645 AEs were noted in 233 patients (49.3%) who were included in the ITT population. Sixty-nine serious AEs in 51 patients were reported, but all of them were not directly attributable to administration of RLAI. This prospective, open-label study showed improvements in symptom and AEs and a significant increase in BMI during 48 weeks of biweekly RLAI treatment. The rate of study completion was 39.0% and the remission rate among those who completed the study was 65.2%. None of the serious AEs were directly related to the administration of RLAI.
    International clinical psychopharmacology 02/2014; · 3.35 Impact Factor
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    ABSTRACT: Organic Field-Effect Transistors On page 288, Hoichang Yang, Se Hyun Kim, and co-workers demonstrate low-voltage-operated high-performance triethylsilylethynyl anthradithiophene (TES-ADT)-based organic field-effect transistors by introducing simple and facile solution-processed interface engineering to lowcapacitance dielectrics, yielding surface-mediated layer-like crystals of TES-ADT with more-efficient charge transport, in comparison with the intrinsically multigrain structures of pentacene crystals.
    Advanced Materials 01/2014; 26(2):194. · 14.83 Impact Factor
  • Organic Electronics 01/2014; · 3.84 Impact Factor
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    ABSTRACT: Hydrophobic organo-compatible but low-capacitance dielectrics (10.5 nFcm(-2) ), polystyrene-grafted SiO2 could induce surface-mediated large crystal grains of face-to-face stacked triethylsilylethynyl anthradithiophene (TES-ADT), producing more efficient charge-carrier transport, in comparison to μm-sized pentacene crystals containing a face-to-edge packing. Low-voltage operating TES-ADT OFETs showed good device performance (μFET ≈ 1.3 cm(2) V(-1) s(-1) , Vth ≈ 0.5 V, SS ≈ 0.2 V), as well as excellent device reliability.
    Advanced Materials 01/2014; 26(2):288-292. · 14.83 Impact Factor
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    ABSTRACT: Circadian rhythm disturbance is highly prevalent in attention deficit hyperactivity disorder (ADHD). Recently, the association between the CLOCK gene and ADHD has been demonstrated in clinical samples, and the CLOCK gene's role was thought to be mediated by rhythm dysregulation. Meanwhile, ADHD has been suggested as the extreme end of a continuously distributed trait that can be found in the general population. Therefore, we examined two possibilities: (1) an ADHD-related continuous trait may be associated with the CLOCK gene, and (2) this association may be mediated by the degree of individuals' evening preference. To explore these possibilities, we performed a quantitative trait locus association study with a sample of 1,289 healthy adults. The Wender Utah Rating Scale (WURS) and the Composite Scale of Morningness (CSM) were utilized to measure the quantitative traits. Quantitative association analysis was performed using PLINK software. We found that rs1801260 (=T3111C) was associated with WURS scores in both allele-wise (p = 0.018) and haplotype-wise analyses (range of p values: 0.0155-0.0171) in male participants only. After controlling for the CSM total score as a covariate, the strength of the association did not change at all, suggesting that the association was not mediated by evening preference. Despite the very weak association signal, our results provide evidence that the CLOCK gene's association with ADHD in clinical samples may be generalizable to traits measured in the normal population. However, as our results failed to show a mediating role of evening preference, ongoing efforts are needed to identify the mechanisms by which the CLOCK gene determines ADHD-related traits.
    European Archives of Psychiatry and Clinical Neuroscience 09/2013; · 2.75 Impact Factor
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    ABSTRACT: An In/Ga-free doping method of zinc oxide (ZnO) is demonstrated utilizing a printable charge transfer doping layer (CTDL) based on (3-aminopropyl)triethoxysilane (APS) molecules. The self-assembled APS molecules placed on top of ZnO thin-films lead to n-type doping of ZnO and filling shallow electron traps, due to the strong electron-donating characteristics of the amine group in APS molecules. The CTDL doping can tune the threshold voltage and the moblity of the ZnO thin-film transistors (TFTs) as one vary the grafting density of the APS moleucles and the thickness of the underneath ZnO thin-films. From an optimized condition, high performance ZnO TFTs can be achieved that exhibit an electron mobility as high as 4.2 cm2/Vs with an on/off current ratio larger than 107. More importantly, the method is applicaple to simple inkjet processes, which lead to produce high-performance depletion load ZnO inverters through selective deposition of CTDL on ZnO thin-films.
    ACS Applied Materials & Interfaces 09/2013; · 5.01 Impact Factor
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    ABSTRACT: The close association between mucinous histology and microsatellite instability (MSI) may have hindered the evaluation of prognostic significance of mucinous histology. The aim of this retrospective study was to investigate whether mucinous histology was associated with a worse prognosis, independent of MSI status, compared to nonmucinous histology in patients with stage III colon cancer. This study enrolled 394 consecutive patients with stage III colorectal cancer treated with adjuvant FOLFOX after curative resection (R0). Clinicopathological information was retrospectively reviewed. Tumors were analyzed for MSI by polymerase chain reaction to determine MSI status. Kaplan-Meier method, log-rank test, and Cox proportional hazard regression models were used. The estimated rate of 3-year disease-free survival (DFS) in patients with nonmucinous adenocarcinoma (NMA 79.2 %) was significantly greater than that in patients with mucinous adenocarcinoma (MA) and adenocarcinoma with mucinous component (MC) (56.9 %; log-rank, P = 0.002). In univariate analysis, histology (NMA vs. MA/MC), American Joint Committee on Cancer stage (IIIA, IIIB, and IIIC), and lymphovascular invasion (present vs. absent) were significantly associated with DFS. In multivariate analysis, mucinous histology (MA/MC) was associated with decreased DFS in all patients (hazard ratio 1.82, 95 % confidence interval 1.03-3.23, P = 0.0403). In patients with MA/MC, no difference in DFS was observed between MSI and microsatellite stability (log-rank, P = 0.732). Mucinous histology is an independent poor prognostic factor for DFS in patients with stage III colon cancer after adjuvant FOLFOX chemotherapy.
    Annals of Surgical Oncology 08/2013; · 4.12 Impact Factor
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    ABSTRACT: We report performance optimization and stability analysis of aerosol-jet-printed electrolyte-gated transistors (EGTs) based on the polymer semiconductor poly(3-hexylthiophene) (P3HT). EGTs were optimized with respect to printed P3HT thickness and the completed device annealing temperature. EGTs with relatively thin P3HT films (∼50 nm) annealed at 120 °C have the best performance and display an unusual combination of metrics including sub-1-V operation, ON/OFF current ratios of 10(6), OFF currents of <10(-10) A (<10(-6) A cm(-2)), saturation hole mobilities of 1.3 cm(2) V(-1) s(-1), threshold voltages of -0.3 V, and subthreshold swings of 70 mV decade(-1). Furthermore, optimized EGTs printed on polyester substrates are extremely robust to bias stress and repeated mechanical bending strain. Collectively, the results suggest that optimized P3HT-based EGTs are promising devices for printed, flexible electronics.
    ACS Applied Materials & Interfaces 07/2013; · 5.01 Impact Factor
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    ABSTRACT: A growing body of evidence suggests that the circadian molecular system is involved in the pathogenic and therapeutic mechanisms underlying bipolar disorders. Lithium, a representative mood stabilizer, has been reported to induce the Period2 (PER2) gene; however, the underlying molecular mechanisms require further study. We found that lithium upregulated PER2 expression at the transcriptional level in neuronally differentiated SH-SY5Y human neuroblastoma cells. Promoter reporter analyses using serial deletions of the PER2 promoter revealed that two early growth response 1 (Egr1)-binding sites (EBS) between positions -180 and -100 are required for maximal activation of the PER2 promoter by lithium. Ectopic expression of Egr1 enhanced lithium-induced PER2 promoter activity, while a point mutation in EBS abolished it. Electrophoretic mobility shift assays and chromatin immunoprecipitation indicated that Egr1 bound directly to the PER2 promoter. Stimulation of the extracellular-signal regulated kinase (ERK)1/2/Elk1 pathway by lithium was functionally linked to PER2 expression through Egr1 induction, and lithium-induced PER2 expression was strongly attenuated by depletion of Egr1 by siRNA. Lithium also upregulated the expression of Per2 and Egr1 in mouse frontal cortex. Induction of Per2 by lithium was attenuated in Egr1(-/-) mice. In conclusion, lithium stimulates PER2 transcription through the ERK/Elk1/Egr1 pathway in neuronal cells, indicating a connection between the ERK-Egr1 pathway and a circadian gene system in the mechanism of action of lithium.
    Biochimica et Biophysica Acta 06/2013; · 4.66 Impact Factor
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    ABSTRACT: RATIONALE: Clozapine affects the extracellular signal-regulated kinase 1/2 (ERK1/2) pathway in the brain, which plays an important role in its antipsychotic action. However, previous findings are inconsistent, and related molecular mechanisms require further clarification. OBJECTIVES: Time- and dose-dependent effects of clozapine on the ERK1/2 pathway and its regulatory mechanism were investigated in rat frontal cortex. METHODS AND RESULTS: At 15, 30, 60, and 120 min after intraperitoneal injection of clozapine (5, 10, and 20 mg/kg), changes in ERK1/2, its upstream canonical kinases (Raf1 and mitogen-activated protein kinase kinase 1/2 [MEK1/2]), and its downstream molecule (p90 ribosomal S6 kinase [p90RSK]) were investigated in rat frontal cortex. At 15 min, p-Raf1, p-MEK1/2, p-ERK1/2, and p-p90RSK all increased dose-dependently. At 30 min, p-ERK1/2 and p-p90RSK showed no significant changes, while dose-dependent increases in p-Raf1 and p-MEK1/2 were found. At 60 and 120 min, although p-ERK1/2 and p-p90RSK decreased, increases in p-Raf1 and p-MEK1/2 were maintained. A clozapine-induced reduction in ERK1/2 phosphorylation was evident at both tyrosine and threonine residues, suggesting the involvement of dual specificity phosphatases (DUSPs; mitogen-activated protein kinase phosphatases [MKPs]). mRNA expression of seven Dusps that can dephosphorylate ERK1/2 were examined; Mkp-1 (Dusp1) mRNA increased following clozapine treatment. Moreover, MKP-1 protein and phosphatase activity increased, and binding of MKP-1 to ERK1/2 was also upregulated by clozapine administration. CONCLUSIONS: In rat frontal cortex, clozapine regulates ERK1/2 phosphorylation via MKP-1, which induces uncoupling between Raf1-MEK1/2 and ERK1/2-p90RSK activity. These findings suggest an important role of MKP-1 in the mechanism of action of clozapine.
    Psychopharmacology 06/2013; · 4.06 Impact Factor
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    ABSTRACT: We examined the reliability and factor structure of the Korean version of the 20-item Subjective Well-being Under Neuroleptic Treatment Scale (SWN-20) with Korean patients of schizophrenia and drew comparisons with the factors of the original authors and of comparable studies from Greece and Turkey to uncover evidences of possible cultural differences in the conceptualization of subjective well-being. The SWN-20 was found to be reliable and the factors seemed to reflect the emphasis often found in Asia on the wholeness of mind and body, and of self, others, and surroundings. Nonetheless, some crucial commonalities with other studies regarding the first primary factor suggested that a measure of well-being that is relatively consistent across cultures may be derived.
    Comprehensive psychiatry 06/2013; · 2.08 Impact Factor
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    ABSTRACT: Intracerebroventricular (ICV) injection of ouabain, a specific Na/K-ATPase inhibitor, induces behavioral changes in rats in a putative animal model of mania. The binding of ouabain to Na/K-ATPase affects signaling molecules in vitro, including ERK1/2 and Akt, which promote protein translation. We have also reported that ERK1/2 and Akt in the brain are involved in the ouabain-induced hyperactivity of rats. In this study, rats were given an ICV injection of ouabain, and then their frontal cortices were examined to determine the effects of ouabain on the mTOR/p70S6K/S6 signaling pathway and protein translation, which are important in modifications of neural circuits and behavior. Rats showed ouabain-induced hyperactivity up to 8 h following injection, and increased phosphorylation levels of mTOR, p70S6K, S6, eIF4B, and 4E-BP at 1, 2, 4, and 8 h following ouabain injection. Immunohistochemical analyses revealed that increased p-S6 immunoreactivity in the cytoplasm of neurons by ouabain was evident in the prefrontal, cingulate, and orbital cortex. These findings suggested increased translation initiation in response to ouabain. The rate of protein synthesis was measured as the amount of [(3)H]-leucine incorporation in the cell-free extracts of frontal cortical tissues, and showed a significant increase at 8 h after ouabain injection. These results suggest that ICV injection of ouabain induced activation of the protein translation initiation pathway regulated by ERK1/2 and Akt, and prolonged hyperactivity in rats. In conclusion, protein translation pathway could play an important role in ouabain-induced hyperactivity in a rodent model of mania.
    Progress in Neuro-Psychopharmacology and Biological Psychiatry 05/2013; · 3.55 Impact Factor

Publication Stats

665 Citations
496.14 Total Impact Points

Institutions

  • 2014
    • Yeungnam University
      Onyang, South Chungcheong, South Korea
  • 2010–2014
    • Seoul National University
      • • Research Institute of Veterinary Medicine
      • • Medical Research Center
      • • Department of Biomedical Sciences
      Sŏul, Seoul, South Korea
    • Inha University
      Chemulpo, Incheon, South Korea
  • 2012–2013
    • University of Minnesota Duluth
      Duluth, Minnesota, United States
  • 2009–2013
    • Eulji University
      • Department of Psychiatry
      Sŏul, Seoul, South Korea
    • Seoul National University Bundang Hospital
      • Department of Neuropsychiatry
      Seoul, Seoul, South Korea
  • 2007–2013
    • Yonsei University Hospital
      • Department of Internal Medicine
      Seoul, Seoul, South Korea
  • 2006–2013
    • Seoul National University Hospital
      • Department of Neuropsychiatry
      Sŏul, Seoul, South Korea
    • Pohang University of Science and Technology
      • Department of Chemical Engineering
      Antō, North Gyeongsang, South Korea
  • 2011–2012
    • Konkuk University
      • Research Center for Transcription Control
      Sŏul, Seoul, South Korea
    • Yonsei University
      • • Division of Medical Oncology
      • • Department of Internal Medicine
      Seoul, Seoul, South Korea
    • Kyung Hee University
      • Graduate School of East-West Medical Science
      Sŏul, Seoul, South Korea
  • 2008
    • Sungkyunkwan University
      • Department of Psychiatry
      Sŏul, Seoul, South Korea
  • 2003
    • CHA University
      • College of Medicine
      Sŏul, Seoul, South Korea