Yu Jin Kim

Seoul National University Bundang Hospital, Sŏul, Seoul, South Korea

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Publications (143)365.36 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: With increasing annealing temperature (Tanneal), the magnitude of the electric fields for the antiferroelectric-to-ferro-electric (EAF) and ferroelectric-to-antiferroelectric (EFA) transition of a 9.2 nm thick Hf0.3Zr0.7O2 film decreased. The energy storage densities of the Hf0.3Zr0.7O2 films crystallized at 400 °C, 500 °C, and 600 °C were as large as 42.2 J/cm3, 40.4 J/cm3, and 28.3 J/cm3, respectively, at the electric field of 4.35 MV/cm. The maximum dielectric constant of the Hf0.3Zr0.7O2 film crystallized at 600 °C was the largest (∼46) as it had the smallest EAF and EFA, whereas the leakage current density of the film crystallized at 400 °C was the smallest. The 400 °C of Tanneal was the optimum condition for energy storage application. (© 2014 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim)
    physica status solidi (RRL) - Rapid Research Letters 10/2014; 9999. · 2.39 Impact Factor
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    ABSTRACT: Organic bulk heterojunction photovoltaic devices based on a series of three naphtho[2,1-b:3,4-b′]dithiophene (NDT) derivatives blended with phenyl-C71-butyric acid methyl ester were studied. These three derivatives, which have NDT units with various thiophene-chain lengths, were employed as the donor polymers. The influence of their molecular structures on the correlation between their solar-cell performances and their degree of crystallization was assessed. The grazing-incidence angle X-ray diffraction and atomic force microscopy results showed that the three derivatives exhibit three distinct nanoscale morphologies. We correlated these morphologies with the device physics by determining the J–V characteristics and the hole and electron mobilities of the devices. On the basis of our results, we propose new rules for the design of future generations of NDT-based polymers for use in bulk heterojunction solar cells.
    ChemPhysChem 08/2014; · 3.35 Impact Factor
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    ABSTRACT: We designed and synthesized a dithienobenzodithiophene (DTBDT)-based molecule with a planar molecular geometry, DTBDT-TTPD, for the fabrication of solution-processable organic solar cells (OSCs). DTBDT-TTPD exhibited both a low optical band gap of 1.88 eV and a low-lying highest occupied molecular orbital (HOMO) energy level of –5.61 eV, indicating that DTBDT-TTPD is a promising electron donor for use in OSCs. OSCs prepared with DTBDT-TTPD as the electron donor and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as the electron acceptor were fabricated. An optimized power conversion efficiency of 4.98% with a high short circuit current of 10.6 mA/cm2 was achieved after finely tuning the morphology through an annealing step. These results indicate that DTBDT-TTPD is an effective compound for producing very promising characteristics in small molecule solar cell devices.
    J. Mater. Chem. A. 08/2014;
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    ABSTRACT: Phlebectasia, also known as venous aneurysm, is a rare condition, especially in the upper part of the body. The authors present an unusual case of aneurysm-like dilatation of the periorbital vein with a previous blunt trauma history, along with its corresponding venous anatomy. In addition, the proper diagnostic process is described and the need for prompt removal of periorbital phlebectasia emphasized.
    Journal of Plastic Reconstructive & Aesthetic Surgery 08/2014; · 1.44 Impact Factor
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    ABSTRACT: We report on tuning of the interfacial properties of a highly sensitive organic photodiode by introducing a buffer layer between the anode and the semiconductor layer. The effects of different buffer layers consisting of a self-assembled monolayer (SAM), PEDOT:PSS, and pentacene on the morphology and crystallinity of the upper-deposited bulk heterojunction semiconductor layer are carefully analyzed combined with electrical analysis. The active layer is controlled to be nearly homogeneous and to have low crystallinity by using a SAM or PEDOT:PSS buffer layers, whereas a highly crystalline morphology is realized by using the pentacene buffer layer. When exposed to light pulses, the external quantum efficiency and thus the photocurrent are slightly higher for the PEDOT:PSS-based photodiode; however the dark current is the lowest for the pentacene-based photodiode. We discuss the origin of the high sensitivity (a detectivity of 1.3 × 10(12) Jones and a linear dynamic range of 95 dB) of the pentacene-based photodiode, particularly in terms of the morphology-driven low dark current.
    Physical Chemistry Chemical Physics 07/2014; · 4.20 Impact Factor
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    ABSTRACT: A series of small molecules that contained identical π-spacers (ethyne), a central diketopyrrolopyrrole (DPP) unit, and different aromatic electron-donating end-groups were synthesized and used in organic solar cells (OSCs) to study the effect of electron-donating groups on the device performance. The three compounds, DPP-A-Ph, DPP-A-Na, and DPP-A-An, possessed intense absorption bands that covered a wide range, from 350 to 750 nm, and relatively low HOMO energy levels, from -5.50 to -5.55 eV. DPP-A-An, which contained anthracene end-groups, demonstrated a stronger absorbance and a higher hole mobility than DPP-A-Ph, which contained phenyl groups, and DPP-A-Na, which contained naphthalene units. The power-conversion efficiencies (PCEs) of OSCs based on organic:PC71 BM blends (1:1, w/w) with a processed DIO additive were 3.93 % for DPP-A-An, 3.02 % for DPP-Na, and 2.26 % for DPP-A-Ph. These findings suggest that a DPP core that is functionalized with electron-donating capping groups constitutes a promising new class of solution-processable small molecules for OSC applications.
    Chemistry - An Asian Journal 07/2014; · 4.57 Impact Factor
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    ABSTRACT: Combined pulmonary fibrosis and emphysema (CPFE) have different pulmonary function tests (PFTs) and outcomes than idiopathic pulmonary fibrosis (IPF). The intention of this study was to identify unknown differences between CPFE and IPF by a retrospective comparison of clinical data including baseline and annual changes in pulmonary function, comorbidities, laboratory findings, clinical characteristics and cause of hospitalization.
    Tuberculosis and Respiratory Diseases 07/2014; 77(1):18-23.
  • Advanced Energy Materials 07/2014; · 14.39 Impact Factor
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    ABSTRACT: Vancomycin-resistant enterococci (VRE) are one of the leading causes of nosocomial infection at intensive care unit (ICU). Rapid and sensitive detection of VRE infection is in high demand for timely and suitable antibiotic treatment. Here, we optimized a distinct DNA-based diagnostic technique, loop-mediated isothermal amplification (LAMP) for rapid detection of the presence of vanA gene, a critical component of the gene cluster required for vancomycin resistance. Amplification efficiency was optimal at 62 ˚C and with 2mM MgSO4. The detection limit of the DNA template was 80pg and LAMP amplicons were detected within 40min; thereby suggesting a potential applicability of LAMP as a sensitive and urgent diagnostic method. Furthermore, positive LAMP reaction was directly detected with the naked-eye by monitoring the formation of a white precipitate or the color change induced by hydroxyl naphtol blue (HNB) dye. Finally, 56 clinical isolates were successfully tested for the presence of vanA gene by LAMP, which was determined to be more sensitive than PCR. Together, our results clearly demonstrate the usefulness of LAMP for the diagnosis of VRE infection.
    Journal of microbiological methods. 06/2014;
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    ABSTRACT: A solution-processed alkylselenophene-substituted benzodithiophene (BDT) small molecule, namely, 3,3′-((4,8-bis(5-(2-ethylhexyl)selenophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl)bis(thiophene-5,2-diyl))bis(5-octyl-1-(thiophen-2-yl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione) (BDTSe-TTPD), with broad absorption and suitable energy levels was synthesized. The widely used solvents o-dichlorobenzene (o-DCB), chlorobenzene (CB) or chloroform (CF) were used as the spin-coating solvent, to fabricate efficient photovoltaic devices with BDTSe-TTPD as the donor material and PC71BM as the acceptor. Devices made from a CF solution demonstrated better performance in terms of short-circuit current, fill factor and power conversion efficiency, as compared to the devices made from the o-DCB and CB solutions. Finally, by optimizing the thickness of the active layer, a power conversion efficiency of 4.37% was achieved on devices with an area of 0.09 cm2, under 100 mW cm−2 of simulated AM 1.5 irradiation.
    J. Mater. Chem. C. 06/2014; 2(25).
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    ABSTRACT: The TiN/Hf0.5Zr0.5O2/TiN capacitor can endure up to 109 times the electric cycling, which is promising for the next‐generation memory. RuO2 top electrode was reduced during annealing due to the reactive TiN bottom electrode, resulting in the degradation of the ferroelectric properties and endurance. The endurance of the TiN/Hf0.5Zr0.5O2/TiN capacitors is optimized by changing the film thickness and the post‐annealing temperature.
    physica status solidi (RRL) - Rapid Research Letters 06/2014; 8(6). · 2.39 Impact Factor
  • Qing Jin, Ling Li, Yu Jin Kim, Nam Soo Han
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    ABSTRACT: AimsLeuconostoc citreum is an important lactic acid bacterium in fermented foods, but dextran production often causes undesired ropiness. To prevent this side effect, a dextran-free mutant needs to be created.Methods and ResultsHomologous recombination of the dextransucrase gene (dsrC) was conducted using a segregationally unstable plasmid, pCBM32-DSUDs. A mutant was obtained on sucrose agar medium, and a site-specific insertional inactivation in the gene was confirmed. When cultured in sucrose medium, the mutant strain produced no dextransucrase or dextran. Additionally, it showed a longer lag phase (9 h) than the wild type strain (3 h), providing new insights into the role of dextransucrase in carbohydrate metabolism of Leuconostoc.Conclusions In this study, a dextransucrase knock-out mutant was constructed. It was found that L. citreum dextransucrase not only synthesizes dextran for cell protection but also provide fructose as an important carbon source for cell growth.Significance and Impact of the StudyThis knock-out mutation was generated for the first time in L. citreum. The dextran-free mutant has the potential to be used for various industrial purposes, including as a starter culture for production of non-viscous fermented foods and as a dextran-free host for production of recombinant proteins.This article is protected by copyright. All rights reserved.
    Journal of Applied Microbiology 06/2014; · 2.20 Impact Factor
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    ABSTRACT: MET, a cell surface receptor for hepatocyte growth factor, is involved in the development of triple-negative/basal-like breast cancer (TNBC/BLBC). However, its utility as a therapeutic target in this subtype of breast cancer is poorly understood. To evaluate MET fully as a potential therapeutic target for TNBC/BLBC, we investigated the relationship between MET expression and clinical outcomes of patients with breast cancer and the functional effect of MET inhibition. Using automated immunohistochemistry (Ventana), we analyzed MET expression in 924 breast cancer patients with relevant clinicopathologic parameters. BLBC showed the strongest relationship with MET expression (57.5%, p < 0.001). High expression of MET in breast cancer resulted in poor overall survival (p = 0.001) and disease-free survival (DFS, p = 0.010). MET expression was relatively high in TNBC cell lines, and the silencing of MET via small interfering RNA reduced cell proliferation and migration. We observed reduced TNBC cell viability after treatment with the MET inhibitor PHA-665752. In the most drug-resistant cell line, MDA-MB-468, which showed elevated epidermal growth factor receptor (EGFR) expression, silencing of EGFR resulted in increased sensitivity to PHA-665752 treatment. We confirmed that PHA-665752 synergizes with the EGFR inhibitor erlotinib to decrease the viability of MDA-MB-468 cells. TNBC patients coexpressing MET and EGFR showed significantly worse DFS than that in patients expressing EGFR alone (p = 0.021). Our findings strongly suggest that MET may be a therapeutic target in TNBC and that the combined therapy targeting MET and EGFR may be beneficial for the treatment of TNBC/BLBC patients.
    International Journal of Cancer 05/2014; 134(10). · 6.20 Impact Factor
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    ABSTRACT: To evaluate the effect of side chain characteristics on the photovoltaic performance of small molecules containing both benzodithiophene (BDT) and thienopyrroledione (TPD), we designed and synthesized two such molecules, one containing a branched 2-ethylhexyl (2EH) side chain on the BDT unit () and the other containing a linear n-octyl (C8) side chain on the BDT unit (). The optical and electrochemical properties and crystalline structures of these molecules were examined. Compared to , showed stronger light absorption, longer-range ordering and shorter π-π stacking distances between backbones. As a result, the power conversion efficiency of a bulk heterojunction solar cell based on (2.40%) was substantially higher than that of the device (1.12%).
    Physical Chemistry Chemical Physics 03/2014; · 4.20 Impact Factor
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    ABSTRACT: We report a series of benzotriazole-based semicrystalline π-conjugated polymers with noncovalent conformational locks for applications in polymer field-effect transistors. The benzotriazole moiety is a versatile electron-deficient building block that offers two chemically functionalizable sites, 2(N) and 5, 6(C) positions, allowing easy modulation of the solution processability and electronic structures of the resulting polymers. Fluorine or alkoxy substituents were introduced to the benzotriazole unit to enhance the molecular ordering through intra- and intermolecular F···S, F···H–C, C–F···πF, or S···O attractive interactions. The fluorinated polymer (PTBTz-F) showed remarkably enhanced hole mobility (μh = 1.9 cm2/(V·s), on/off ratio = 8 × 107) upon thermal annealing at 305 °C, compared to the unsubstituted one (PTBTz) (μh = 7.0 × 10–3 cm2/(V·s), on/off ratio = 3 × 106). Alkoxy unit substitution (PTBTz-OR) also improved the carrier mobility up to 0.019 cm2/(V·s) with an on/off ratio of 4 × 105. Fluorine or alkoxy substitution induced tight interchain ordering with edge-on orientation, as confirmed by X-ray diffraction measurements. In particular, fluorinated PTBTz-F showed high thermal stability (Td 453 °C) and the remarkable device characteristics with deep frontier orbital levels.
    Chemistry of Materials. 03/2014; 26(6):2147–2154.
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    ABSTRACT: To elucidate the origin of the formation of the ferroelectric phase in Hf0.5Zr0.5O2 films, the effects of film strain and crystallographic orientation on the properties were examined. Using a (111)-textured Pt bottom electrode, Hf0.5Zr0.5O2 films with a (111)-preferred texture inappropriate for transforming their phase from non-ferroelectric tetragonal to ferroelectric orthorhombic phase were deposited. In contrast, randomly oriented Hf0.5Zr0.5O2 films, grown on the TiN electrode, showed feasible ferroelectric properties due to their transformation to the ferroelectric orthorhombic phase. The origin of such transformation is the large in-plane tensile strain for the elongation of the c-axis of the tetragonal phase.
    01/2014; 104(7).
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    ABSTRACT: Two small molecules named BT-TPD and TBDT-TTPD with a thieno[3,4-c]pyrrole-4,6-dione (TPD) unit were designed and synthesized for solution-processed bulk-heterojunction solar cells. Their thermal, electrochemical, optical, charge-transport, and photovoltaic characteristics were investigated. These compounds exhibit strong absorption at 460-560 nm and low highest occupied molecular orbital levels (-5.36 eV). Field-effect hole mobilities of these compounds are 1.7-7.7×10(-3) cm(2) V(-1) s(-1) . Small-molecule organic solar cells based on blends of these donor molecules and a acceptor display power conversion efficiencies as high as 4.62 % under the illumination of AM 1.5G, 100 mW cm(-2) .
    Chemistry - An Asian Journal 01/2014; · 4.57 Impact Factor
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    ABSTRACT: Rhabdomyosarcoma (RMS) is the most commonly occurring type of soft tissue tumor in children. However, it is rare in adults, and therefore, very little is known about the most appropriate treatment strategy for adult RMS patients. We performed genomic analysis of RMS cells derived from a 27-year-old male patient whose disease was refractory to treatment. A peritoneal seeding nodule from the primary tumor, pleural metastases, malignant pleural effusion, and ascites obtained during disease progression, were analyzed. Whole exome sequencing revealed 23 candidate variants, and 10 of 23 mutations were validated by Sanger sequencing. Three of 10 mutations were present in both primary and metastatic tumors, and 3 mutations were detected only in metastatic specimens. Comparative genomic hybridization array analysis revealed prominent amplification in the 12q13-14 region, and more specifically, the CDK4 proto-oncogene was highly amplified. ALK overexpression was observed at both protein and RNA levels. However, an ALK fusion assay using NanoString technology failed to show any ALK rearrangements. Little genetic heterogeneity was observed between primary and metastatic RMS cells. We propose that CDK4, located at 12q14, is a potential target for drug development for RMS treatment.
    Scientific Reports 01/2014; 4:3623. · 5.08 Impact Factor
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    ABSTRACT: Objective Advanced airway management is one of the fundamental skills of advanced cardiac life support (ACLS). A failed initial intubation attempt (FIIA) is common and has shown to be associated with adverse events. We analysed the association between FIIA and the overall effectiveness of ACLS. Methods Using emergency department (ED) Out-of-hospital cardiac arrest (OHCA) registry data from 2008 to 2012, non-traumatic ED-resuscitated adult OHCA patients on whom endotracheal intubation was initially tried were identified. Prehospital and demographic factors and patient outcomes were retrieved from the registry. The presence of a FIIA was determined by reviewing nurse-documented CPR records. The primary outcome was achieving a return of spontaneous circulation (ROSC). The secondary outcomes were time to ROSC and the ROSC rate during the first 30 minutes of ED resuscitation. Results The study population (n = 512) was divided into two groups based on the presence of a FIIA (N = 77). Both groups were comparable without significant differences in demographic or prehospital factors. In the FIIA group, the unadjusted and adjusted odds ratios (ORs) for achieving a ROSC were 0.50 (95% confidence interval [CI], 0.31-0.81) and 0.40 (95% CI, 0.23-0.71), respectively. Multivariable median regression analysis revealed that FIIA was associated with an average delay of 3 minutes in the time to ROSC (3.08; 95% CI, 0.08-5.80). Competing risk regression analysis revealed a significantly slower ROSC rate during the first 15 minutes (adjusted subhazard ratio, 0.52; 95% CI, 0.35-0.79) in the FIIA group. Conclusion FIIA is an independent risk factor for the decreased effectiveness of ACLS.
    Resuscitation 01/2014; · 4.10 Impact Factor
  • Organic Electronics 01/2014; · 3.84 Impact Factor

Publication Stats

364 Citations
365.36 Total Impact Points

Institutions

  • 2014
    • Seoul National University Bundang Hospital
      • Department of Emergency Medicine
      Sŏul, Seoul, South Korea
    • MEDIPOST Biomedical Research Institute
      Sŏul, Seoul, South Korea
  • 2013–2014
    • Pohang University of Science and Technology
      • Department of Chemical Engineering
      Geijitsu, North Gyeongsang, South Korea
    • Hallym University Medical Center
      • Department of Pathology
      Seoul, Seoul, South Korea
  • 2011–2014
    • Seoul National University
      • Department of Materials Science and Engineering
      Sŏul, Seoul, South Korea
  • 2007–2014
    • Yonsei University Hospital
      • Department of Internal Medicine
      Sŏul, Seoul, South Korea
  • 2012–2013
    • Kongju National University
      Gongju, South Chungcheong, South Korea
    • Sungkyunkwan University
      • • Department of Pathology
      • • School of Medicine
      Sŏul, Seoul, South Korea
    • Korea Research Institute of Bioscience and Biotechnology KRIBB
      • Functional Metabolite Research Center
      Anzan, Gyeonggi Province, South Korea
  • 2011–2012
    • Myongji Hospital
      Kōyō, Gyeonggi Province, South Korea
  • 2009–2012
    • Chungbuk National University
      • Department of Food Science and Technology
      Chinch'ŏn, North Chungcheong, South Korea
  • 2008–2012
    • Gachon University
      • Department of Internal Medicine
      Sŏngnam, Gyeonggi Province, South Korea
    • Hallym University
      • College of Medicine
      Seoul, Seoul, South Korea
  • 2007–2008
    • Hanyang University
      • Department of Biomedical Engineering
      Sŏul, Seoul, South Korea
  • 2003–2007
    • Inha University
      • • College of Medicine
      • • Department of Plastic Surgery
      Seoul, Seoul, South Korea
  • 2004
    • Inha University Hospital
      Sinhyeon, South Gyeongsang, South Korea