Dong Hoon Choi

Korea Institute of Science and Technology, Sŏul, Seoul, South Korea

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Publications (52)159.57 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: We obtained fibroblast- (FDM) and preosteoblast- (PDM) derived matrices in vitro from their respective cells. Our hypothesis was that these naturally occurring cell-derived matrices (CDMs) would provide a better microenvironment for the multi-lineage differentiation of human mesenchymal stromal cells (hMSCs) than those based on traditional single-protein-based platforms. Cells cultured for 5-6 days were decellularized with detergents and enzymes. The resulting matrices showed a fibrillar surface texture. Under osteogenic conditions, human bone-marrow-derived stromal cells (HS-5) exhibited higher amounts of both mineralized nodule formation and alkaline phosphatase (ALP) expression than those cultured on plastic or gelatin. Osteogenic markers (Col I, osteopontin, and cbfa1) and ALP activity from cells cultured on PDM were notably upregulated at 4 weeks. The use of FDM significantly improved the cellular expression of chondrogenic markers (Sox 9 and Col II), while downregulating that of Col I at 4 weeks. Both CDMs were more effective in inducing cellular synthesis of glycosaminoglycan content than control substrates. We also investigated the effect of matrix surface texture on hMSC (PT-2501) differentiation; soluble matrix (S-matrix)-coated substrates exhibited a localized fibronectin (FN) alignment, whereas natural matrix (N-matrix)-coated substrates preserved the naturally formed FN fibrillar alignment. hMSCs cultured for 4 weeks on N-matrices under osteogenic or chondrogenic conditions deposited a greater amount of calcium and proteoglycan than those cultured on S-matrices as assessed by von Kossa and Safranin O staining. In contrast to the expression levels of lineage-specific markers for cells cultured on gelatin, FN, or S-matrices, those cultured on N-matrices yielded highly upregulated levels. This study demonstrates not only the capacity of CDM for being an effective inductive template for the multi-lineage differentiation of hMSCs, but also the critical biophysical role that the matrix fibrillar texture itself plays on the induction of stem cell differentiation.
    Cell and Tissue Research 05/2014; · 3.68 Impact Factor
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    ABSTRACT: An optimized electrodropping system produces homogeneous core-shell microcapsules (C-S MCs) by using poly(L-lactic-co-glycolic acid) (PLGA) and alginate. Fluorescence imaging clearly shows the C-S domain in the MC. For release control, the use of high-molecular-weight PLGA (HMW 270 000) restrains the initial burst release of protein compared to that of low-MW PLGA (LMW 40 000). Layer-by-layer (LBL) assembly of chitosan and alginate on MCs is also useful in controlling the release profile of biomolecules. LBL (7-layer) treatment is effective in suppressing the initial burst release of protein compared to no LBL (0-layer). The difference of cumulative albumin release between HMW (7-layer LBL) and LMW (0-layer LBL) PLGA is determined to be more than 40% on day 5. When dual angiogenic growth factors (GFs), such as platelet-derived GF (PDGF) and vascular endothelial GF (VEGF), are encapsulated separately in the core and shell domains, respectively, the VEGF release rate is much greater than that of PDGF, and the difference of the cumulative release percentage between the two GFs is about 30% on day 7 with LMW core PLGA and more than 45% with HMW core PLGA. As for the angiogenic potential of MC GFs with human umbilical vein endothelial cells (HUVECs), the fluorescence signal of CD31+ suggests that the angiogenic sprout of ECs is more active in MC-mediated GF delivery than conventional GF delivery, and this difference is significant, based on the number of capillary branches in the unit area. This study demonstrates that the fabrication of biocompatible C-S MCs is possible, and that the release control of biomolecules is adjustable. Furthermore, MC-mediated GFs remain in an active form and can upregulate the angiogenic activity of ECs.
    Small 04/2013; · 7.82 Impact Factor
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    ABSTRACT: We report the fabrication of photofunctional Co-Cr alloy plate that is prepared by a simple modification process for photodynamic application. Photoinduced functionality is provided by the photosensitizer of hematoporphyrin (Hp) that initially generates reactive oxygen species (ROS) such as superoxide anion radical and singlet oxygen. The photosensitizer with carboxyl group was chemically bonded to the surface of the Co-Cr alloy plate by esterification reaction. Microstructure and elemental composition of the Co-Cr alloy plate were checked with scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDS). Fabrication of the photofunctionality of the Co-Cr alloy plate was confirmed with X-ray photoelectron spectroscopy (XPS), reflectance UV-Vis absorption, and emission spectroscopy. Reactive oxygen generation from the photofunctional Co-Cr alloy plate was confirmed by using the decomposition reaction of 1,3-diphenylisobenzofuran (DPBF). The results suggest that the immobilized photosensitizer molecules on the surface of Co-Cr alloy plate still possess their optical and functional properties including reactive oxygen generation. To open the possibility for its application as a photodynamic material to biological system, the fabricated photofunctional Co-Cr alloy is applied to the decomposition of smooth muscle cells.
    International Journal of Photoenergy 04/2013; 2013. · 2.66 Impact Factor
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    ABSTRACT: Two anthracene-based star-shaped conjugated small molecules, 5′,5″-(9,10-bis((4-hexylphenyl)ethynyl)anthracene-2,6-diyl)bis(5-hexyl-2,2′-bithiophene), HBantHBT, and 5′,5″-(9,10-bis(phenylethynyl)anthracene-2,6-diyl)bis(5-hexyl-2,2′-bithiophene), BantHBT, are used as electron-cascade donor materials by incorporating them into organic photovoltaic cells prepared using a poly((5,5-E-alpha-((2-thienyl)methylene)-2-thiopheneacetonitrile)-alt-2,6-[(1,5-didecyloxy)naphthalene])) (PBTADN):[6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) blend. The small molecules penetrate the PBTADN:PC71BM blend layer to yield complementary absorption spectra through appropriate energy level alignment and optimal domain sizes for charge carrier transfer. A high short-circuit current (JSC) and fill factor (FF) are obtained using solar cells prepared with the ternary blend. The highest photovoltaic performance of the PBTADN:BantHBT:PC71BM blend solar cells is characterized by a JSC of 11.0 mA cm−2, an open circuit voltage (VOC) of 0.91 V, a FF of 56.4%, and a power conversion efficiency (PCE) of 5.6% under AM1.5G illumination (with a high intensity of 100 mW−2). The effects of the small molecules on the ternary blend are investigated by comparison with the traditional poly(3-hexylthiophene) (P3HT):[6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) system.
    Advanced Functional Materials 03/2013; 23(12). · 10.44 Impact Factor
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    ABSTRACT: Recently, biological applications start to be reimplemented into the applications which exploit many cores of GPUs for better computation performance. Therefore, by providing virtualized GPUs to VMs in cloud computing environment, many biological applications will willingly move into cloud environment to enhance their computation performance and utilize infinite cloud computing resource while reducing expenses for computations. In this paper, we propose a BioCloud system architecture that enables VMs to use GPUs in cloud environment. Because much of the previous research has focused on the sharing mechanism of GPUs among VMs, they cannot achieve enough performance for biological applications of which computation throughput is more crucial rather than sharing. The proposed system exploits the pass-through mode of PCI express (PCI-E) channel. By making each VM be able to access underlying GPUs directly, applications can show almost the same performance as when those are in native environment. In addition, our scheme multiplexes GPUs by using hot plug-in/out device features of PCI-E channel. By adding or removing GPUs in each VM in on-demand manner, VMs in the same physical host can time-share their GPUs. We implemented the proposed system using the Xen VMM and NVIDIA GPUs and showed that our prototype is highly effective for biological GPU applications in cloud environment.
    BioMed research international. 01/2013; 2013:939460.
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    Dong Hoon Choi, Heeseung Jo, Myungho Lee
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    ABSTRACT: The current GPU virtualization techniques incur large overheads when executing application programs mainly due to the fine-grain time-sharing scheduling of the GPU among multiple Virtual Machines (VMs). Besides, the current techniques lack of portability, because they include the APIs for the GPU computations in the VM monitor. In this paper, we propose a low overhead and high performance GPU virtualization approach on a heterogeneous HPC system based on the open-source Xen. Our proposed techniques are tailored to the bio applications. In our virtualization framework, we allow a VM to solely occupy a GPU once the VM is assigned a GPU instead of relying on the time-sharing the GPU. This improves the performance of the applications and the utilization of the GPUs. Our techniques also allow a direct pass-through to the GPU by using the IOMMU virtualization features embedded in the hardware for the high portability. Experimental studies using microbiology genome analysis applications show that our proposed techniques based on the direct pass-through significantly reduce the overheads compared with the previous Domain0 based approaches. Furthermore, our approach closely matches the performance for the applications to the bare machine or rather improves the performance.
    KIPS Transactions on Software and Data Engineering. 01/2013; 2(2).
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    ABSTRACT: Danshen is a traditional Chinese medicine with many beneficial effects on cardiovascular diseases. The aim of this study was to evaluate the mechanisms responsible for the antiatherogenic effect of water soluble Danshen extracts (DEs). Rat vascular smooth muscle cells (VSMCs) and human umbilical vein endothelial cells (HUVECs) were treated with DE. To evaluate the effects of DE in vivo, carotid balloon injury and tail vein thrombosis were induced in Sprague-Dawley (SD) rats and iliac artery stent was induced in New Zealand white rabbits. The inhibitory action of DE on platelet aggregation was confirmed with an impedance aggregometer. DE inhibited the production of reactive oxygen species, and the migration and proliferation of platelet-derived growth factor-BB stimulated VSMCs. Furthermore, DE prevented inflammation and apoptosis in HUVECs. Both effects of DE were reconfirmed in both rat models. DE treatment attenuated platelet aggregation in both in vivo and ex vivo conditions. Pretreatment with DE prevented tail vein thrombosis, which is normally induced by κ-carrageenan injection. Lastly, DE-treated rabbits showed decreased in-stent restenosis of stented iliac arteries. These results suggest that water soluble DE modulates key atherogenic events in VSMCs, endothelial cells, and platelets in both in vitro and in vivo conditions.
    Evidence-based Complementary and Alternative Medicine 01/2013; 2013:623639. · 1.72 Impact Factor
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    ABSTRACT: This study sought to compare everolimus-eluting stents (EES) with zotarolimus-eluting stents (ZES) in patients with acute myocardial infarction (AMI). There is a paucity of data to exclusively evaluate the safety and efficacy of second-generation drug-eluting stents (DES) in the setting of AMI. The present study enrolled 3,309 AMI patients treated with ZES (n = 1,608) or EES (n = 1,701) in a large-scale, prospective, multicenter registry-KAMIR (Korea Acute Myocardial Infarction Registry). Propensity score matching was applied to adjust for differences in baseline clinical and angiographic characteristics, producing a total of 2,646 patients (1,343 receiving ZES, and 1,343 receiving EES). Target lesion failure (TLF) was defined as the composite of cardiac death, recurrent nonfatal myocardial infarction, or target lesion revascularization. Major clinical outcomes at 1 year were compared between the 2 propensity score-matched groups. After propensity score matching, baseline clinical and angiographic characteristics were similar between the 2 groups. Clinical outcomes of the propensity score-matched patients showed that, despite similar incidences of recurrent nonfatal myocardial infarction and in-hospital and 1-year mortality, patients in the EES group had significantly lower rates of TLF (6.5% vs. 8.7%, p = 0.029) and probable or definite stent thrombosis (0.3% vs. 1.6%, p < 0.001), compared with those in the ZES group. Furthermore, there was a numerically lower rate of target lesion revascularization (1.2% vs. 2.2%, p = 0.051) in the EES group than in the ZES group. In this propensity-matched comparison, EES seems to be superior to ZES in reducing TLF and stent thrombosis in patients with AMI.
    JACC. Cardiovascular Interventions 09/2012; 5(9):936-45. · 1.07 Impact Factor
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    ABSTRACT: Latest High Performance Computing (HPC) platforms are built with heterogeneous chips such as multicore microprocessors and multicore GPUs (Graphic Processing units), thus they are commonly called as Heterogeneous High Performance Computing (HPC) platforms. Parallelizing applications on such platforms is mostly dominated by SIMD style of parallelism mainly to exploit GPUs' excellent floatingpoint performance. However, it is a restricted parallel model because the multiple CPU cores are not participating in the parallel execution, thus the full performance potential of heterogeneous architectures is not exploited. In this paper, we propose a generalized parallelization methodology to efficiently map applications onto the heterogeneous architectures and to exploit their full performance potential. For the methodology, we develop strategies to map parallel tasks onto different components of the heterogeneous architectures. A general parallel execution model beyond SIMD is adopted in the task mapping.
    01/2012;
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    ABSTRACT: Fabrication and photophysical study of photofunctional nanoporous alumina membrane (PNAM) were performed, and its application of photodynamic antimicrobial chemotherapy (PACT) was investigated. Nanoporous alumina membrane (NAM) was fabricated by two-step aluminium anodic oxidation process. Surface of the fabricated NAM was modified with organo-silane agent to induce covalent bonding between NAM and a photosensitizer (PtCP: [5,10,15-triphenyl-20-(4-methoxycarbonylphenyl)-porphyrin] platinum). PtCP was covalently bonded to the surface of the modified NAM by nucleophilic acyl substitution reaction process. The morphology and the photophysical properties of the fabricated PNAM were confirmed with field emission scanning electron microscope (FE-SEM), steady-state spectroscopies, and nanosecond laser-induced time-resolved spectroscopy. For the efficacy study of PNAM in PACT, an enveloped animal virus, vesicular stomatitis virus (VSV), was utilized as a target organism. Antiviral effect of the PNAM-PACT was measured by the extent of suppression of plaque-forming units (PFU) after the light irradiation. In the cultures inoculated with PACT-treated VSV, the suppression of PFU was prominent, which demonstrates that PNAM is a potential bio clean-up tool.
    Journal of Nanomaterials 01/2012; 2012. · 1.55 Impact Factor
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    ABSTRACT: Dendritic cells (DC) present α-galactosylceramide (αGalCer) to invariant T-cell receptor-expressing natural killer T cells (iNKT) activating these cells to secrete a variety of cytokines, which in turn results in DC maturation and activation of other cell types, including NK cells, B cells, and conventional T cells. In this study, we showed that αGalCer-pulsing of antigen-activated CD8 T cells before adoptive transfer to tumor-bearing mice caused a marked increase in donor T-cell proliferation, precursor frequency, and cytotoxic lymphocyte activity. This effect was interleukin (IL)-2 dependent and involved both natural killer T cells (NKT) and DCs, as mice lacking IL-2, NKTs, and DCs lacked any enhanced response to adoptively transferred αGalCer-loaded CD8 T cells. iNKT activation was mediated by transfer of αGalCer from the cell membrane of the donor CD8 T cells onto the αGalCer receptor CD1d which is present on host DCs. αGalCer transfer was increased by prior activation of the donor CD8 T cells and required AP-2-mediated endocytosis by host DCs. In addition, host iNKT cell activation led to strong IL-2 synthesis, thereby increasing expansion and differentiation of donor CD8 T cells. Transfer of these cells led to improved therapeutic efficacy against established solid tumors in mice. Thus, our findings illustrate how αGalCer loading of CD8 T cells after antigen activation in vitro may leverage the therapeutic potential of adoptive T-cell therapies.
    Cancer Research 12/2011; 71(24):7442-51. · 9.28 Impact Factor
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    ABSTRACT: In patients with ST-segment elevation myocardial infarction (STEMI) and multivessel disease, complete revascularization (CR) for non-culprit lesions is not routinely recommended. The aim of this study was to compare the clinical outcomes of multivessel compared with infarct-related artery (IRA)-only revascularization in patients undergoing primary percutaneous coronary intervention (PCI) for STEMI. From the Korean Acute Myocardial Infarction Registry (KAMIR) database, 1,094 STEMI patients with multivessel disease who underwent primary PCI with drug-eluting stents were enrolled in this study. The patients were divided into two groups: culprit-vessel-only revascularization (COR, n=827) group; multivessel revascularization, including non-IRA (MVR, n=267) group. The primary endpoint of this study included major adverse cardiac events (MACEs), such as death, myocardial infarction, or target or nontarget lesion revascularization at one year. There was no difference in clinical characteristics between the two groups. During the one-year follow-up, 102 (15.2%) patients in the COR group and 32 (14.2%) in the MVR group experienced at least one MACE (p=0.330). There were no differences between the two groups in terms of rates of death, myocardial infarction, or revascularization (2.1% vs. 2.0%, 0.7% vs. 0.8%, and 11.7% vs. 10.1%, respectively; p=0.822, 0.910, and 0.301, respectively). The MACE rate was higher in the incompletely revascularized patients than in the completely revascularized patients (15% vs. 9.5%, p=0.039), and the difference was attributable to a higher rate of nontarget vessel revascularization (8.6% vs. 1.8%, p=0.002). Although multivessel angioplasty during primary PCI for STEMI did not reduce the MACE rate compared with culprit-vessel-only PCI, CR was associated with a lower rate of repeat revascularization after multivessel PCI.
    Korean Circulation Journal 12/2011; 41(12):718-25.
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    ABSTRACT: In patients with non-ST-elevation myocardial infarction (NSTEMI), current guidelines did not recommend optimal revascularization management in multivessel coronary artery disease. We compared clinical outcomes between multivessel revascularization and culprit-only revascularization in this setting. A total of 1919 patients with multivessel disease (1011 patients; multivessel revascularization group, 908 patients; culprit-only revascularization group) diagnosed as NSTEMI was enrolled in a nationwide prospective Korea Acute Myocardial Infarction Registry (KAMIR) from November 2005 to January 2008. The primary end-points were major adverse cardiac events (MACE), all-causes of deaths, myocardial infarction (MI), and repeated percutaneous coronary intervention (PCI) during 1-year clinical follow-up. Also, subgroup analysis was performed in patients with high TIMI (Thrombolysis In Myocardial Infarction) risk score (≥ 4) to find efficacy of multivessel PCI in high-risk patients. Baseline clinical characteristics and the risk factors of coronary artery disease were similar between both groups. In angiography, three-vessel lesion was more presented in the multivessel group (46.1% vs. 40.9%, p = 0.024) and rates of left anterior descending and left main stem coronary artery as culprit vessel were higher in the multivessel group (p = 0.003 and p = 0.001 respectively). In-hospital mortality was higher in the culprit-only group (1.4% vs. 2.9%, p = 0.025). Primary end-points occurred in 241 patients (15.5%) during 1-year follow-up. Multivessel revascularization reduced MACEs [hazard ratio (HR) 0.658, 95% confidence interval (CI) 0.45 to 0.96, p = 0.031], death or myocardial infarction (HR 0.58, 95% CI 0.35 to 0.97, p = 0.037) and non-target vessel revascularization (HR 0.44, 95% CI 0.24 to 0.81, p = 0.008). There were no significant differences in target lesion revascularization (TLR; HR 1.38, 95% CI 0.51 to 3.71, p = 0.529) and target vessel revascularization (TVR; HR 0.28, 95% CI 0.05 to 1.47, p = 0.131). In subgroup analysis in patients with a higher TIMI risk score, similar results were presented. Multivessel revascularization in multivessel coronary artery disease presenting with NSTEMI showed better clinical outcomes without significant in-stent restenosis and progression of diseased-vessel compared to culprit-only revascularization.
    International journal of cardiology 12/2011; 153(2):148-53. · 6.18 Impact Factor
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    ABSTRACT: There are few data available on the prognosis of painless ST-segment elevation myocardial infarction (STEMI). The aim of this study was to determine the incidence, clinical characteristics, and outcomes of painless STEMI. We analyzed the Korea Acute Myocardial Infarction Registry (KAMIR) study, which enrolled 7,288 patients with STEMI (61.8 ± 12.8 years old, 74% men; painless STEMI group, n = 763; painful STEMI group, n = 6,525). End points were in-hospital mortality and 1-year major adverse cardiac events (MACEs). Patients with painless STEMI were older and more likely to be women, nonsmokers, diabetic, and normolipidemic and to have a higher Killip class. The painless group had more in-hospital deaths (5.9% vs 3.6%, p = 0.026) and 1-year MACEs (26% vs 19%, p = 0.002). In Cox proportional hazards analysis, hypotension (hazard ratio [HR] 4.40, 95% confidence interval [CI] 1.41 to 13.78, p = 0.011), low left ventricular ejection fraction (HR 3.12, 95% CI 1.21 to 8.07, p = 0.019), and a high Killip class (HR 3.48, 95% CI 1.19 to 10.22, p = 0.023) were independent predictors of 1-year MACEs in patients with painless STEMI. In conclusion, painless STEMI was associated with more adverse outcomes than painful STEMI and late detection may have contributed significantly to total ischemic burden. These results warrant more investigations for methodologic development in the diagnosis of silent ischemia and painless STEMI.
    The American journal of cardiology 11/2011; 109(3):337-43. · 3.58 Impact Factor
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    ABSTRACT: We investigated whether statin therapy could be beneficial in patients with acute myocardial infarction (AMI) who have baseline low-density lipoprotein cholesterol (LDL-C) levels below 70 mg/dl. Intensive lipid-lowering therapy with a target LDL-C value <70 mg/dl is recommended in patients with very high cardiovascular risk. However, whether to use statin therapy in patients with baseline LDL-C levels below 70 mg/dl is controversial. We analyzed 1,054 patients with AMI who had baseline LDL-C levels below 70 mg/dl and survived at discharge from the Korean Acute MI Registry between November 2005 and December 2007. They were divided into 2 groups according to the prescribing of statins at discharge (statin group n = 607; nonstatin group n = 447). The primary endpoint was the composite of 1-year major adverse cardiac events, including death, recurrent MI, target vessel revascularization, and coronary artery bypass grafting. Statin therapy significantly reduced the risk of the composite primary endpoint (adjusted hazard ratio [HR]: 0.56; 95% confidence interval [CI]: 0.34 to 0.89; p = 0.015). Statin therapy reduced the risk of cardiac death (HR: 0.47; 95% CI: 0.23 to 0.93; p = 0.031) and coronary revascularization (HR: 0.45, 95% CI: 0.24 to 0.85; p = 0.013). However, there were no differences in the risk of the composite of all-cause death, recurrent MI, and repeated percutaneous coronary intervention rate. Statin therapy in patients with AMI with LDL-C levels below 70 mg/dl was associated with improved clinical outcome.
    Journal of the American College of Cardiology 10/2011; 58(16):1664-71. · 14.09 Impact Factor
  • American heart journal 07/2011; 162(1):e21-2. · 4.65 Impact Factor
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    ABSTRACT: Photoinduced energy- and electron-transfer processes of donor-σ-acceptor molecules composed of [1,2,4,5-tetrakis((E)-2-(50-hexyl-2,20-bithiophen-5-yl)vinyl)benzene] (HPBT) with one, two and four entities of perylenediimide (PDI) forming HPBT–PDIn (n = 1, 2 and 4) have been examined in this article by utilizing steady-state absorption and emission, computational, electrochemical and time-resolved transient absorption studies. The HPBT–PDIn molecules are connected through long non-conjugated σ-bonds that may prevent the direct overlap of HPBT and PDI energy levels. Electrochemical studies suggest the exothermic photoinduced electron transfer processes when HPBT and PDI are selectively excited. Upon excitation the HPBT entity, the steady-state emission and femtosecond transient absorption measurements of HPBT–PDIn revealed an efficient energy transfer from the singlet excited HPBT to PDI with time constants on the order of ∼1010 s−1. The energy donor–acceptor distance, r = ∼22 Å, is calculated from the experimental energy transfer rates using Förster theory and from the MO calculations using ab initio B3LYP/6-311G method. By selective excitation the PDI entity, the electron-transfer processes take place from HPBT to the singlet excited PDI with time constants on the order of ∼108 s−1. The slow rates of electron transfer and energy transfer processes indicated that these molecules tend to take conformations with relatively long distance between HPBT and PDI entities.
    Journal of Photochemistry and Photobiology A: Chemistry. 02/2011; 218(1):17-25.
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    ABSTRACT: The optimal loading dose of clopidogrel in Asian patients with ST-segment elevation myocardial infarction (STEMI) has not been fully investigated. We compared bleeding, vascular complications, and midterm outcomes of a 300-mg versus a 600-mg loading dose of clopidogrel in a large series of Korean patients with STEMI undergoing primary percutaneous coronary intervention (PCI). A total of 2,664 STEMI patients (age 61.96 ± 11.91 years, men 70.4%) who underwent primary PCI were enrolled in this study. The patients were divided into a standard loading dose group (300 mg; n = 1,447 patients) and a high loading dose group (600 mg; n = 1,217 patients). Bleeding and vascular complications, and in-hospital and clinical outcomes up to 12 months were compared between the 2 groups. In-hospital bleeding and vascular complications were similar between the 2 groups. There were no differences in bleeding and vascular complications and in 1- and 12-month clinical outcomes, including mortality, myocardial infarction, repeated PCI, and major adverse cardiac events, between the 2 groups. These findings were consistent even after the propensity score-matched analysis. The standard loading dose of clopidogrel may be as safe and similarly effective as the high loading dose in Asian STEMI patients undergoing primary PCI.
    American heart journal 02/2011; 161(2):373-382.e1-3. · 4.65 Impact Factor
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    ABSTRACT: Assessment of risk at time of discharge could be a useful tool for guiding postdischarge management. The aim of this study was to develop a novel and simple assessment tool for better hospital discharge risk stratification. The study included 3,997 hospital-discharged patients with acute myocardial infarction who were enrolled in the nationwide prospective Korea Acute Myocardial Infarction Registry-1 (KAMIR-1) from November 2005 through December 2006. The new risk score system was tested in 1,461 hospital-discharged patients who were admitted from January 2007 through January 2008 (KAMIR-2). The new risk score system was compared to the Global Registry of Acute Coronary Events (GRACE) postdischarge risk model during a 12-month clinical follow-up. During 1-year follow-up, all-cause death occurred in 228 patients (5.7%) and 81 patients (5.5%) in the development and validation cohorts, respectively. The new risk score (KAMIR score) was constructed using 6 independent variables related to the primary end point using a multivariable Cox regression analysis: age, Killip class, serum creatinine, no in-hospital percutaneous coronary intervention, left ventricular ejection fraction, and admission glucose based on multivariate-adjusted risk relation. The KAMIR score demonstrated significant differences in its predictive accuracy for 1-year mortality compared to the GRACE score for the developmental and validation cohorts. In conclusion, the KAMIR score for patients with acute myocardial infarction is a simpler and better risk scoring system than the GRACE hospital discharge risk model in prediction of 1-year mortality.
    The American journal of cardiology 01/2011; 107(7):965-971.e1. · 3.58 Impact Factor
  • Jung-Ho Um, Sang Bae Park, J.H. Seo, Dong Hoon Choi
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    ABSTRACT: Recently the importance of genomic data analysis is growing to realize the personalized treatment of human cancers. Next generation sequencing (NGS) technique is a cost-effective way to get such data sets for the cancer data analysis. Hence, most of bioinformatics research groups use NGS technique to process their study. Since NGS produces data sets of lots of short reads, it requires more computing resources to analyze those sets of data. To solve this issue, cloud computing is a candidate that can elastically manage the requirement of computing resources. In this paper, we propose a bio-cloud service for large scale NGS data analysis based on virtualized computing infrastructure. It has been developed by collaboration of KISTI and KOBIC to enhance the productivity of KOBIC's RNA re-sequencing study.
    Computer Sciences and Convergence Information Technology (ICCIT), 2011 6th International Conference on; 01/2011

Publication Stats

265 Citations
159.57 Total Impact Points

Institutions

  • 2010–2014
    • Korea Institute of Science and Technology
      • Center for Biomaterials
      Sŏul, Seoul, South Korea
  • 2013
    • Chonbuk National University
      Tsiuentcheou, North Jeolla, South Korea
    • Korea Institute of Science and Technology Information (KISTI)
      Daiden, Daejeon, South Korea
  • 2012–2013
    • Yonsei University
      • College of Medicine
      Sŏul, Seoul, South Korea
    • Tianjin Medical University
      T’ien-ching-shih, Tianjin Shi, China
  • 2010–2013
    • Yonsei University Hospital
      • Department of Internal Medicine
      Sŏul, Seoul, South Korea
  • 2007–2013
    • Korea University
      • Department of Chemistry
      Sŏul, Seoul, South Korea
  • 2011
    • Pohang University of Science and Technology
      • Division of Molecular and Life Sciences
      Andong, North Gyeongsang, South Korea
    • Yeungnam University
      • Division of Internal Medicine
      Onyang, South Chungcheong, South Korea
  • 2009–2011
    • Chonnam National University
      • Department of Internal Medicine
      Gwangju, Gwangju, South Korea
    • Chonnam National University Hospital
      Sŏul, Seoul, South Korea