Sang Hyun Lee

Sejong University, Sŏul, Seoul, South Korea

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Publications (293)715.65 Total impact

  • Neurology 04/2015; 84(16):e121. DOI:10.1212/WNL.0000000000001497 · 8.30 Impact Factor
  • Hye Young Yun, Young Ho Kim, Sang Hyun Lee
    Plant Disease 04/2015; DOI:10.1094/PDIS-03-15-0313-PDN · 2.74 Impact Factor
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    ABSTRACT: Meningiomas are the most common benign intracranial tumors and make up 13-26% of all primary intracranial tumors. Clinical presentation of hemorrhage is rare in these tumors occurring in approximately 1.3% of cases and subdural hemorrhages are even more uncommon. The mechanism of hemorrhage is still unclear and may vary according to histologic type, location and the type of hemorrhage. We experienced a case of 61-year-old woman with a benign meningioma presenting as a subdural hemorrhage. She developed sudden onset of headache right after aggressively coughing. Her headache persisted for a week before she was admitted to the emergency room of National Cancer Center. She had a past medical history of ovarian cancer which had been treated and was allegedly recurrence-free for 2 years. At the time of admission, a headache was the only symptom and imaging studies showed a right frontal hemorrhagic subdural mass lesion accompanying an ipsilateral subdural hematoma. Elective surgery was performed and intraoperative findings revealed the hallmark characteristics of a meningioma with mixed stage diffuse subdural hematoma. Permanent pathology result determined it was a conventional meningioma (World Health Organization grade I). From this case, we discuss the rare presentation of subdural hemorrhage in meningioma and related points by reviewing the literature of previous studies.
    04/2015; 3(1):30-3. DOI:10.14791/btrt.2015.3.1.30
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    ABSTRACT: A conformal coating strategy with nanocarbon to enhance photoelectrochemical responses and the long-term stability of ZnO quantum dots is described. Strong anchoring bonds between a ZnO core and nanocarbon shell ameliorate the poor electrochemical stability of ZnO (such as photocorrosion) in liquid electrolyte. The conjugation of the graphene QD and C60 to the ZnO QDs leads to 71% and 99% quenching of the UV photoluminescence (PL) emission, respectively. Also, the decay time of the nanocomposites at UV wavelengths measured much faster than that for the reference of bare ZnO QDs. The moderate energy states and good charge conductance of the nanocarbons result in ultrafast charge transport from the ZnO core to the nanocarbon shell. Thereby, the ZnO core–nanocarbon shell quantum dots shows significantly improved light harvesting performance. The PEC cell test for water oxidation and conventional degradation test using organic dyes exhibited that the photoelectrochemical activities could be significantly improved. At 1.23 V (vs. RHE) in pH 6.9 electrolyte, 6 times enhanced photocurrent density was achieved by the conformal coating with C60 (0.235 mA/cm2 for ZnO–C60 photoanodes). In particular, the strong Zn–O–C bond structures on the ZnO surface prevented photoinduced holes from being consumed by the photocorrosion reaction of ZnO, thereby improving long-term stability.
    Nano Energy 04/2015; 13:258. DOI:10.1016/j.nanoen.2015.02.013 · 10.21 Impact Factor
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    ABSTRACT: To increase algal growth in treated livestock waste water, we designed a culture system targeting symbiotic bacteria. Microbacterium sp. HJ1 is a symbiotic bacteria associated with Chlorella vulgaris, which was found to increase the growth rate when controlled by nitrogen addition. The validated analysis model for nitrogen source mixture was used to analyze the growth and final pH of Microbacterium sp. HJ1, in different compositions of nitrogen sources, by elucidating the functions of each nitrogen ions such as NO3−, NO2−, and NH4+. By modifying the growth medium made from treated livestock waste water with additional nitrogen source, we were able to increase dry cell weight (DCW) of C. vulgaris by 65.7% and chlorophyll a contents by 78.8%. This is an example of an indirect method to increase algal biomass by changing the population of symbiotic bacteria, and it is the practical application of positive effects from symbiotic bacteria to the host.
    Biomass and Bioenergy 03/2015; 74. DOI:10.1016/j.biombioe.2015.01.012 · 3.41 Impact Factor
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    ABSTRACT: Microbial algal system can serve as a potential source for the production of much high value bioproducts and biofuels. The quality and intensity of light are the key elements to optimize the production of algal biomass and fatty acid contents. This study presents the effect of differential LED flashing light conditions on the growth of microalgae, Acutodesmus obliquus. The induced light stress was optimized for its biomass and fatty acid content. The microalgae are exposed to various frequency of intermittent LED flashing light (blue and red lights) at three different phases in the 18day cell growth (log, lag and stationary phase). The frequency of light flashing rate was adjusted to 120, 10, 5, 3.75, and 1times per min. The effect of light stress on growth and fatty acids composition of A. obliquus induced an increase in algae growth and fatty acid production. Different optimal timing for light stress was subjected to elucidate the effect of light stress on algae growth and fatty acid production. The results showed an increase in the algae growth (1.2mg/L of chl a content) under light stress condition at FT10 (flashing time, 10times per min) from the initial day (log phase) compared with the control experiment (0.4mg/L of chl a content). However, the total fatty acids (71mg/g) and volumetric FAME production (9.4ml/l) level was found to be significant under FT5 (flashing time, 5times per min), adopting flashing light from day 10 (stationary phase). TEM studies also revealed the deposition of lipid to be largest in the 18day old cells under flashing light (FT5) condition, representing maximum accumulation of lipids bodies (up to 770nm diameter in particle size) occupying approximately 42% of the total area of the cell. Copyright © 2015 Elsevier B.V. All rights reserved.
    Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 03/2015; 145:245-253. DOI:10.1016/j.saa.2015.03.035 · 2.13 Impact Factor
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    Mayumi Kitagawa, Sang Hyun Lee
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    ABSTRACT: Understanding the molecular network of orderly mitotic exit to re-establish a functional interphase nucleus is critical because disordered mitotic exit inevitably leads to genomic instability. In contrast to the mechanisms of the entrance to mitosis, however, little is known about what controls the orderly exit from mitosis, particularly in mammalian cells. The chromosomal passenger complex (CPC), which is composed of Aurora B, INCENP, Borealin and Survivin, is one of the most widely studied and highly conserved hetero-tetrameric complexes. The CPC orchestrates proper chromosome segregation with cytokinesis by targeting to specific locations at different stages of mitosis. Recent studies reveal that controlling CPC localization and Aurora B kinase activity also serves as a key surveillance mechanism for the orderly mitotic exit. This ensures the reformation of a functional interphase nucleus from condensed mitotic chromosomes by delaying mitotic exit and cytokinetic processes in response to defects in chromosome segregation. In this review, we will summarize the latest insight into the molecular mechanisms that regulate CPC localization during mitotic exit and discuss how targeting Aurora B activity to different locations at different times impacts executing multiple mitotic exit events in order and recently proposed surveillance mechanisms. Finally, we briefly discuss the potential implication of deregulated Aurora B in inducing genomic damage and tumorigenesis with current efforts in targeting Aurora B activity for anti-cancer therapy.
    Frontiers in Cell and Developmental Biology 03/2015; 3:14. DOI:10.3389/fcell.2015.00014
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    ABSTRACT: Artificial wood films containing cellulose, xylan, and lignin were easily prepared by the dissolution of wood components in 1-ethyl-3-methylimidazolium acetate followed by reconstitution with distilled water. The composition and characteristics of wood films were highly controllable and predictable through the variation of the concentration of each component in the wood solution. The water vapor solubility of the wood films was increased when the xylan content was increased and the content of lignin was decreased. The biodegradability of the artificial wood films was investigated with cellulase from Trichoderma viride. The relative degradability of the wood film prepared with 5% cellulose and 5% lignin was 42%, whereas that of the wood film made with 5% cellulose and 5% xylan was 189%. The biodegradability of cellulose in the wood films correlated well with the content of xylan and lignin, and it was enhanced when the xylan content was increased and the content of lignin was decreased. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42109.
    Journal of Applied Polymer Science 03/2015; 132(25). DOI:10.1002/app.42109 · 1.64 Impact Factor
  • Sang Hyun Lee, Illsoo Sohn
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    ABSTRACT: This letter develops a distributed algorithm for relay pairing in bandwidth exchange (BE) based cooperative forwarding scenarios, where each node can delegate a fraction of its allocated resources to a neighboring node as an incentive for relaying. Determining the relay pairs that maximize the overall network utility yields a non-bipartite matching problem, which incurs a considerable computational load when implemented in a centralized way. To resolve this challenge, we use a message-passing framework to develop an efficient distributed solution. Simulation results verify that the proposed algorithm outperforms existing approaches.
    IEEE Communications Letters 03/2015; 19(3):459-462. DOI:10.1109/LCOMM.2014.2385064 · 1.46 Impact Factor
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    ABSTRACT: Two new naphthalene diglucosides named nepenthosides A (1) and B (2), together with eleven known compounds (3-13), were isolated from the carnivorous plant Nepenthes mirabilis. The structures of these compounds were elucidated based on extensive spectroscopic analysis, including 1D- and 2D-NMR, and MS. The antioxidant activities of compounds 1-13 were evaluated in terms of their peroxyl radical-scavenging (trolox equivalent, TE) and reducing capacities. All isolates showed peroxyl radical-scavenging and reducing activities at concentrations of 1.0 and 10.0 μM. Anti-osteoporotic activities were investigated using murine osteoclastic RAW 264.7 cells. Compounds 1-7 and 9-12 significantly suppressed tartrate-resistant acid phosphatase activity down to 91.13 ± 1.18 to 42.39 ± 1.11 %, relative to the control (100 %) in nuclear factor-κB ligand (RANκL)-induced osteoclastic RAW 264.7 macrophage cells.
    Archives of Pharmacal Research 02/2015; DOI:10.1007/s12272-015-0576-9 · 1.75 Impact Factor
  • Sang Hyun Lee, Sung-Yoon Jung, Jae Kyun Kwon
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    ABSTRACT: The recent interest in short-range optical wireless communication technology driven by the widespread deployment of solid state lighting has led to significant efforts on the standardization of visible light communication. In such efforts, the consideration of dimming support poses fundamental challenges on the VLC system design that have not been addressed elsewhere. This article overviews the technical considerations for enhancing the VLC physical layer by summarizing the state-of-the-art advancements in modulation and coding technologies dedicated to VLC systems. In addition, the technical challenges for system enhancement under lighting restrictions are described.
    IEEE Communications Magazine 02/2015; 53(2):136-143. DOI:10.1109/MCOM.2015.7045402 · 4.46 Impact Factor
  • Sang Hyun Lee, Jae Kyun Kwon
    01/2015; 40(1):240-245. DOI:10.7840/kics.2015.40.1.240
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    ABSTRACT: Wood component-based composite hydrogels have potential applications in biomedical fields owing to their low cost, biodegradability, and biocompatibility. The controllable properties of wood mimetic composites containing three major wood components are useful for enzyme immobilization. Here, lipase from Candida rugosa was entrapped in wood mimetic beads containing cellulose, xylan, and lignin by dissolving wood components with lipase in [Emim][Ac], followed by reconstitution. Lipase entrapped in cellulose/xylan/lignin beads in a 5:3:2 ratio showed the highest activity; this ratio is very similar to that in natural wood. The lipase entrapped in various wood mimetic beads showed increased thermal and pH stability. The half-life times of lipase entrapped in cellulose/alkali lignin hydrogel were 31- and 82-times higher than those of free lipase during incubation under denaturing conditions of high temperature and low pH, respectively. Owing to their biocompatibility, biodegradability, and controllable properties, wood mimetic hydrogel beads can be used to immobilize various enzymes for applications in the biomedical, bioelectronic, and biocatalytic fields.
    Carbohydrate Polymers 01/2015; 115:223–229. DOI:10.1016/j.carbpol.2014.08.096 · 3.92 Impact Factor
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    ABSTRACT: The methanolic extract of Nepenthes mirabilis (Nepenthaceae) showed significant in vitro antioxidant (peroxyl radical-scavenging and reducing effects) and anti-osteoporotic (pre-osteoclastic RAW 264.7 cells) activities. Phytochemical investigation of chloroform and ethyl acetate partitions of N. mirabilis branches and leaves allowed to isolate 13 compounds (1–13), including two new naphthoquinones, nepenthones F (1) and G (2), together with 11 known compounds. The structures of the isolated compounds were established mainly by extensive analysis of the 1D and 2D NMR, as well as HRMS data. The isolated compounds also were further evaluated for in vitro antioxidant and anti-osteoclast activities. Among them, compounds 10 and 11 showed potent antioxidant effects. While compounds 4 and 12 showed significant inhibition on receptor activation for nuclear factor κB ligand (RANκL)-induced osteoclast formation in murine bone-marrow macrophages.
    Phytochemistry Letters 01/2015; 11. DOI:10.1016/j.phytol.2015.01.009 · 1.54 Impact Factor
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    ABSTRACT: Two new compounds, chrysinoneside A (1) and (-)-trans-chrysanthenol-6-O-β-D-glucopyranoside (2), along with 17 known compounds (3-19) were isolated from Chrysanthemum indicum flowers. The total phenolic and flavonoid contents of various fractions were determined. The EtOAC fraction had the highest total phenolic content (525.84 ± 23.51 mg GAE/g DR) and the total flavonoid content (63.49 ± 3.32 mg QE/g DR). The EtOAc and water fractions showed the greatest peroxyl radical-scavenging capacity and the ability to reduce Cu(I) ions, with ORAC and CUPRAC values ranging from 24.00 ± 0.44 to 28.06 ± 1.35 and 16.90 ± 0.51 to 49.77 ± 0.97 μM, respectively. Compounds 5-11, 18, and 19 displayed strong effects in both peroxyl radical-scavenging and reducing capacity assays at a concentration of 10 μM. The anti-osteoporosis activity of these compounds was also evaluated. Compounds 10, 13, and 19 exhibited the most potent tartrate-resistant acid phosphatase activity in receptor activator of nuclear factor-κB ligand-induced osteoclastic RAW 264.7 cells with values of 105.95 ± 1.18, 110.32 ± 3.95, and 112.58 ± 6.42%, respectively. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.
    Phytotherapy Research 01/2015; 29(4). DOI:10.1002/ptr.5281 · 2.40 Impact Factor
  • Plant Disease 01/2015; DOI:10.1094/PDIS-11-14-1203-PDN · 2.74 Impact Factor
  • Journal of Neurology Neurosurgery & Psychiatry 01/2015; DOI:10.1136/jnnp-2014-309761 · 5.58 Impact Factor
  • Sang Hyun Lee, IllSoo Sohn
    IEEE Transactions on Wireless Communications 01/2015; DOI:10.1109/TWC.2015.2422701 · 2.76 Impact Factor
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    ABSTRACT: Although the varied neurotoxicity of intrathecal (IT) chemotherapy for treatment of childhood acute leukemia is well known, most are related to transient post-puncture headache, drug-induced arachnoiditis, or leukoencephalopathy after methotrexate or cytarabine. Cerebral vasospasm leading to acute infarct after IT chemotherapy is very uncommon in children. Reported herein is a rare case of diffuse cerebral vasospasm with subsequent cerebral infarct after IT cytarabine in a 7-year-old boy with acute lymphoblastic leukemia, who successfully recovered with supportive management, and a review of the literature.
    Pediatrics International 12/2014; 56(6):921-924. DOI:10.1111/ped.12394 · 0.73 Impact Factor
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    ABSTRACT: In this article, we report the results of electrochemical monitoring regarding a multicellular photosynthetic cyanobacterial species using a photoelectrochemical sensor. The sensor utilizes the photosynthesis-based reducing action of the cyanobacteria (Spirulina maxima) on an electrochemical mediator (2-hydroxyl-1,4-naphthoquinone) and reoxidation of the mediator at an electrode. When the amperometric signals from the cyanobacteria are compared with dry cell weight, chlorophyll a concentration, and pH, the amperometric signals from the system show a considerable relationship with the chlorophyll a concentration in the cyanobacteria during the cultivation over 54 days.
    Sensors and Actuators B Chemical 12/2014; 205:9–11. DOI:10.1016/j.snb.2014.08.047 · 3.84 Impact Factor

Publication Stats

3k Citations
715.65 Total Impact Points

Institutions

  • 2015
    • Sejong University
      Sŏul, Seoul, South Korea
    • Gwangju Institute of Science and Technology
      Gwangju, Gwangju, South Korea
  • 2013–2015
    • Duke-NUS Graduate Medical School Singapore
      • PhD Program in Cancer and Stem Cell Biology
      Tumasik, Singapore
    • Kumoh National Institute of Technology
      Sŏul, Seoul, South Korea
    • National Health Insurance Corporation Ilsan Hospital
      Sŏul, Seoul, South Korea
    • Nonsan Hana Hospital
      Ronsan, Chungcheongnam-do, South Korea
  • 2011–2015
    • Hannam University
      • Department of Food and Nutrition
      Daiden, Daejeon, South Korea
    • Korea Atomic Energy Research Institute (KAERI)
      Daiden, Daejeon, South Korea
    • Dankook University
      • Department Architectural Engineering
      Eidō, Chungcheongbuk-do, South Korea
  • 2009–2015
    • Konkuk University
      Sŏul, Seoul, South Korea
    • Rensselaer Polytechnic Institute
      • Department of Chemical and Biological Engineering
      Троя, New York, United States
  • 2004–2015
    • National Cancer Center Korea
      • • Biometric Research Branch
      • • Specific Organs Cancer Branch
      • • Radiation Medicine Branch
      Kōyō, Gyeonggi-do, South Korea
  • 2014
    • Korea Polar Research Institute
      Sŏul, Seoul, South Korea
    • Inje University
      Kŭmhae, Gyeongsangnam-do, South Korea
    • Korea Astronomy and Space Science Institute
      Daiden, Daejeon, South Korea
    • Ulsan University Hospital
      Urusan, Ulsan, South Korea
    • Kongju National University
      • Department of Atmospheric Sciences
      Gongju, Chungcheongnam-do, South Korea
  • 2011–2014
    • Harvard University
      Cambridge, Massachusetts, United States
  • 2010–2014
    • Sungkyunkwan University
      • Samsung Medical Center
      Sŏul, Seoul, South Korea
    • Kangwon National University
      Shunsen, Gangwon, South Korea
  • 2006–2014
    • Korea Forest Research Institute
      Sŏul, Seoul, South Korea
    • Chung-Ang University
      Sŏul, Seoul, South Korea
    • Massachusetts Institute of Technology
      • Department of Civil and Environmental Engineering
      Cambridge, Massachusetts, United States
  • 2002–2014
    • Pusan National University
      • • Department of Internal Medicine
      • • Department of Polymer Science and Engineering
      • • Department of Earth Science Education
      Tsau-liang-hai, Busan, South Korea
    • Samsung Advanced Institute of Technology
      Usan-ri, Gyeonggi Province, South Korea
    • University of Seoul
      • Depatrment of Materials Science and Engineering
      Sŏul, Seoul, South Korea
  • 2009–2013
    • University of Texas at Austin
      • Department of Electrical & Computer Engineering
      Austin, Texas, United States
  • 2012
    • Chungnam National University
      • College of Pharmacy
      Daiden, Daejeon, South Korea
    • University of South Australia
      Tarndarnya, South Australia, Australia
    • Sangji University
      • Department of Pharmaceutical Engineering
      Wŏnju, Gangwon, South Korea
  • 2010–2012
    • Dana-Farber Cancer Institute
      • Department of Cancer Biology
      Boston, Massachusetts, United States
    • Yeungnam University
      • School of Chemical Engineering
      Onyang, South Chungcheong, South Korea
    • Oak Ridge National Laboratory
      Oak Ridge, Florida, United States
  • 2006–2012
    • Korea Research Institute of Standards and Science
      • Division of Physical Metrology
      Sŏul, Seoul, South Korea
    • Tohoku University
      • • Graduate School of Environmental Studies
      • • Center for Interdisciplinary Research
      Sendai, Kagoshima, Japan
  • 2003–2012
    • Chonnam National University
      • • College of Agriculture and Life Sciences
      • • Department of Electrical, Electronic Communication and Computer Engineering
      • • Department of Cardiology
      Gwangju, Gwangju, South Korea
    • Seoul National University Hospital
      • Department of Radiology
      Sŏul, Seoul, South Korea
  • 2005–2010
    • University of California, San Francisco
      • Diller Family Comprehensive Cancer Center
      San Francisco, California, United States
    • University of Ulsan
      • Department of Materials Engineering
      Urusan, Ulsan, South Korea
    • Korea Advanced Institute of Science and Technology
      • Satellite Technology Research Center
      Sŏul, Seoul, South Korea
  • 2003–2010
    • Chonbuk National University
      • Department of Chemical Engineering
      Tsiuentcheou, North Jeolla, South Korea
  • 2005–2009
    • Yonsei University
      • • Department of Civil and Environmental Engineering
      • • Department of Electrical and Electronic Engineering
      Seoul, Seoul, South Korea
  • 2003–2009
    • Pohang University of Science and Technology
      • • Department of Chemical Engineering
      • • Division of Molecular and Life Sciences
      Geijitsu, North Gyeongsang, South Korea
  • 2008
    • Hanyang University
      • Division of Chemical Engineering and Bioengineering
      Sŏul, Seoul, South Korea
  • 2006–2008
    • Inha University
      • Department of Biological Engineering
      Sŏul, Seoul, South Korea
  • 2007
    • Silla University
      Tsau-liang-hai, Busan, South Korea
    • Andong National University
      • School of Materials Science and Engineering
      Antō, Gyeongsangbuk-do, South Korea
  • 2003–2005
    • Electronics and Telecommunications Research Institute
      Sŏul, Seoul, South Korea
  • 2000
    • Seoul National University
      • Department of Physiology
      Sŏul, Seoul, South Korea
  • 1976
    • Hope College
      Holland, Michigan, United States