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Search Results: 1 - 10 of 31704 matches for " Hee-Sun Won "
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Efficient 2-Step Protocol and Its Discriminative Feature Selections in Secure Similar Document Detection
Sang-Pil Kim,Myeong-Sun Gil,Yang-Sae Moon,Hee-Sun Won
Computer Science , 2015,
Abstract: Secure similar document detection (SSDD) identifies similar documents of two parties while each party does not disclose its own sensitive documents to another party. In this paper, we propose an efficient 2-step protocol that exploits a feature selection as the lower-dimensional transformation and presents discriminative feature selections to maximize the performance of the protocol. For this, we first analyze that the existing 1-step protocol causes serious computation and communication overhead for high dimensional document vectors. To alleviate the overhead, we next present the feature selection-based 2-step protocol and formally prove its correctness. The proposed 2-step protocol works as follows: (1) in the filtering step, it uses low dimensional vectors obtained by the feature selection to filter out non-similar documents; (2) in the post-processing step, it identifies similar documents only from the non-filtered documents by using the 1-step protocol. As the feature selection, we first consider the simplest one, random projection (RP), and propose its 2-step solution SSDD-RP. We then present two discriminative feature selections and their solutions: SSDD-LF (local frequency) which selects a few dimensions locally frequent in the current querying vector and SSDD-GF (global frequency) which selects ones globally frequent in the set of all document vectors. We finally propose a hybrid one, SSDD-HF (hybrid frequency), that takes advantage of both SSDD-LF and SSDD-GF. We empirically show that the proposed 2-step protocol outperforms the 1-step protocol by three or four orders of magnitude.
A multilevel analysis of social capital and self-reported health: evidence from Seoul, South Korea
Sehee Han, Heaseung Kim, Hee-Sun Lee
International Journal for Equity in Health , 2012, DOI: 10.1186/1475-9276-11-3
Abstract: We conducted a cross-sectional survey from December 2010 to April 2011 in Seoul, South Korea. The target population included respondents aged 25 years and older who have resided in the same administrative area since 2008. The final sample for this study consisted of 4,730 respondents within all 25 of Seoul's administrative areas.In our final model, individual-level social capital, including network sources (OR = 1.23; 95% CI = 1.11-1.37) and organizational participation (OR = 2.55; 95% CI = 2.11-3.08) was positively associated with good/very good health. Interestingly, the individual × area organizational participation cross-level interaction was negatively associated with good/very good health (OR = 0.40; 95% CI = 0.32-0.50), indicating that in areas with higher organizational participation, individuals with high organizational participation were less likely to report good/very good health when compared to low organizational participation individuals.Our study provides evidence that individual-level social capital is associated with self-reported health, even after controlling for both individual and area-level confounders. Although this study did not find significant relationships between area-level organizational participation and self-reported health, this study found the cross-level interaction for social capital. Hence, in areas with lower organizational participation, the probability of reporting good/very good health is higher for individuals with high organizational participation than individuals with low organizational participation. This study, albeit tentatively, suggests that policy makers should focus upon social capital when making policies which aim to enhance one's health.It has been widely acknowledged that places where people live are a crucial factor for individual health [1-3]. Previous studies have been focused on various physical aspects of places (e.g., environmental pollution) [4]. Other than these factors, there is a growing body of evidenc
Protein Kinase C-Dependent Dephosphorylation of Tyrosine Hydroxylase Requires the B56δ Heterotrimeric Form of Protein Phosphatase 2A
Jung-Hyuck Ahn, Yong Kim, Hee-Sun Kim, Paul Greengard, Angus C. Nairn
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0026292
Abstract: Tyrosine hydroxylase, which plays a critical role in regulation of dopamine synthesis, is known to be controlled by phosphorylation at several critical sites. One of these sites, Ser40, is phosphorylated by a number of protein kinases, including protein kinase A. The major protein phosphatase that dephosphorylates Ser40 is protein phosphatase-2A (PP2A). A recent study has also linked protein kinase C to the dephosphorylation of Ser40 [1], but the mechanism is unclear. PP2A isoforms are comprised of catalytic, scaffold, and regulatory subunits, the regulatory B subunits being able to influence cellular localization and substrate selection. In the current study, we find that protein kinase C is able to phosphorylate a key regulatory site in the B56δ subunit leading to activation of PP2A. In turn, activation of the B56δ-containing heterotrimeric form of PP2A is responsible for enhanced dephosphorylation of Ser40 of tyrosine hydroylase in response to stimulation of PKC. In support of this mechanism, down-regulation of B56δ expression in N27 cells using RNAi was found to increase dopamine synthesis. Together these studies reveal molecular details of how protein kinase C is linked to reduced tyrosine hydroxylase activity via control of PP2A, and also add to the complexity of protein kinase/protein phosphatase interactions.
Anti-Inflammatory Effect of Ginsenoside Rg5 in Lipopolysaccharide-Stimulated BV2 Microglial Cells
Yu Young Lee,Jin-Sun Park,Ji-Sun Jung,Dong-Hyun Kim,Hee-Sun Kim
International Journal of Molecular Sciences , 2013, DOI: 10.3390/ijms14059820
Abstract: Microglia are resident immune cells in the central nervous system. They play a role in normal brain development and neuronal recovery. However, overactivation of microglia causes neuronal death, which is associated with neurodegenerative diseases, such as Parkinson’s disease and Alzheimer’s disease. Therefore, controlling microglial activation has been suggested as an important target for treatment of neurodegenerative diseases. In the present study, we investigated the anti-inflammatory effect of ginsenoside Rg5 in lipopolysaccharide (LPS)-stimulated BV2 microglial cells and rat primary microglia. The data showed that Rg5 suppressed LPS-induced nitric oxide (NO) production and proinflammatory TNF-α secretion. In addition, Rg5 inhibited the mRNA expressions of iNOS, TNF-α, IL-1b, COX-2 and MMP-9 induced by LPS. Further mechanistic studies revealed that Rg5 inhibited the phophorylations of PI3K/Akt and MAPKs and the DNA binding activities of NF-kB and AP-1, which are upstream molecules controlling inflammatory reactions. Moreover, Rg5 suppressed ROS production with upregulation of hemeoxygenase-1 (HO-1) expression in LPS-stimulated BV2 cells. Overall, microglial inactivation by ginsenoside Rg5 may provide a therapeutic potential for various neuroinflammatory disorders.
Anti-Inflammatory Effects of α-Galactosylceramide Analogs in Activated Microglia: Involvement of the p38 MAPK Signaling Pathway
Yeon-Hui Jeong, Yongju Kim, Heebum Song, Young Sun Chung, Seung Bum Park, Hee-Sun Kim
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0087030
Abstract: Microglial activation plays a pivotal role in the development and progression of neurodegenerative diseases. Thus, anti-inflammatory agents that control microglial activation can serve as potential therapeutic agents for neurodegenerative diseases. Here, we designed and synthesized α-galactosylceramide (α-GalCer) analogs to exert anti-inflammatory effects in activated microglia. We performed biological evaluations of 25 α-GalCer analogs and observed an interesting preliminary structure-activity relationship in their inhibitory influence on NO release and TNF-α production in LPS-stimulated BV2 microglial cells. After identification of 4d and 4e as hit compounds, we further investigated the underlying mechanism of their anti-inflammatory effects using RT-PCR analysis. We confirmed that 4d and 4e regulate the expression of iNOS, COX-2, IL-1β, and IL-6 at the mRNA level and the expression of TNF-α at the post-transcriptional level. In addition, both 4d and 4e inhibited LPS-induced DNA binding activities of NF-κB and AP-1 and phosphorylation of p38 MAPK without affecting other MAP kinases. When we examined the anti-inflammatory effect of a p38 MAPK-specific inhibitor, SB203580, on microglial activation, we observed an identical inhibitory pattern as that of 4d and 4e, not only on NO and TNF-α production but also on the DNA binding activities of NF-κB and AP-1. Taken together, these results suggest that p38 MAPK plays an important role in the anti-inflammatory effects of 4d and 4e via the modulation of NF-κB and AP-1 activities.
Hypoxia Antagonizes Glucose Deprivation on Interleukin 6 Expression in an Akt Dependent, but HIF-1/2α Independent Manner
Sung Ji Choi, Ik Jae Shin, Kang-Hoon Je, Eun Kyoung Min, Eun Ji Kim, Hee-Sun Kim, Senyon Choe, Dong-Eog Kim, Dong Kun Lee
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0058662
Abstract: Although both glucose deprivation and hypoxia have been reported to promote cascades of biological alterations that lead to induction of inflammatory mediators, we hypothesized that glucose deprivation and hypoxia might show neutral, synergistic or antagonistic effects to each other on gene expression of inflammatory mediators depending on the regulatory components in their promoters. Gene expression of interleukin 6 (IL-6) was analyzed by real-time PCR, ELISA, or Western blot. Effects of glucose deprivation and/or hypoxia on activation of signaling pathways were analyzed by time-dependent phosphorylation patterns of signaling molecules. We demonstrate that hypoxia antagonized the effects of glucose deprivation on induction of IL-6 gene expression in microglia, macrophages, and monocytes. Hypoxia also antagonized thapsigargin-induced IL-6 gene expression. Hypoxia enhanced phosphorylation of Akt, and inhibition of Akt was able to reverse the effects of hypoxia on IL-6 gene expression. However, inhibition of HIF-1/2α did not reverse the effects of hypoxia on IL-6 gene expression. In addition, phosphorylation of p38, but not JNK, was responsible for the effects of glucose deprivation on IL-6 gene expression.
An Iterative Algorithm for Generalized Mixed Equilibrium Problems and Fixed Points of Nonexpansive Semigroups  [PDF]
Jong Kyu Kim, Salahud din, Won Hee Won Hee
Journal of Applied Mathematics and Physics (JAMP) , 2017, DOI: 10.4236/jamp.2017.52025
Abstract:
In this works, by using the modified viscosity approximation method associated with Meir-Keeler contractions, we proved the convergence theorem for solving the fixed point problem of a nonexpansive semigroup and generalized mixed equilibrium problems in Hilbert spaces.
Obesity and obstructive sleep apnea, bariatric surgery and follow-up post treatment  [PDF]
Won Hee Seo, Christian Guilleminault
Health (Health) , 2013, DOI: 10.4236/health.2013.58A3006
Abstract:

Bariatric surgery is a valid treatment alternative for obese patients with obstructive sleep apnea (OSA), but subjects who are overweight or obese represent a poor model to investigate the role of OSA treatment on cardiovascular variables, calling into question the attribution of cardiovascular and metabolic problems associated with OSA with excess weight. Seventeen patients with significant obesity who demonstrated OSA with a high apnea-hypopnea index (AHI) were treated with bariatric surgery alone after refusal of nasal continuous positive airway pressure (CPAP) treatment. At approximately 3 years post-surgery, subjects demonstrated a significant drop in blood pressure measured at rest, improvement in sleepiness and fatigue visual analogue scales, but continued to complain of daytime sleepiness. Polysomnography in these subjects demonstrated relative improvement in AHI, but patients continued to have a significant number of respiratory events and episodes of flow limitation.  Subsequent treatment with a dental device led to further improvement in nocturnal respiration, but did not reduce AHI to a normal range on repeat polysomnography. In this study we demonstrate that bariatric surgery alone and in conjunction with a dental device may significantly reduce AHI but does not eliminate daytime fatigue and sleepiness. Systematic long term follow-up examining the persistence of sleep related abnormalities should be performed particularly if daytime fatigue or sleepiness is still present in patients with OSA after treatment with bariatric surgery

Protective effect of the methanol extract from Cryptotaenia japonica Hassk. against lipopolysaccharide-induced inflammation in vitro and in vivo
Kang Hee,Bang Tae-Sun,Lee Ji-Won,Lew Jae-Hwan
BMC Complementary and Alternative Medicine , 2012, DOI: 10.1186/1472-6882-12-199
Abstract: Background In folk medicine, the aerial part of Crytotaenia japonica Hassk. (CJ), is applied for treatment of the common cold, cough, urinary problems, pneumonia, and skin rashes. In this paper, the in vitro and in vivo anti-inflammatory activity of CJ methanol extract was tested using lipopolysaccharide (LPS)-induced inflammatory models. Methods We measured nitric oxide (NO), inducible NO synthase (iNOS), and inflammatory cytokine levels from LPS-stimulated mouse peritoneal macrophages. Also, several cellular signaling molecules which regulate the expressions of these inflammatory markers were examined. Finally, we tested whether oral administration of CJ methanol extract might affect the serum cytokine levels in LPS-injected mice. Results CJ methanol extract reduced NO release via iNOS protein inhibition. The extract was also shown to decrease the secretions of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-12. Analysis of signaling molecules showed that CJ inhibited the phosphorylation of STAT1, p38, JNK and ERK1/2 as well as IκBα degradation. Finally, CJ decreased the serum levels of TNF-α and IL-6 in LPS-injected mice. Conclusions Our results demonstrated the anti-inflammatory activity of CJ methanol extract and its possible underlying mechanisms that involve modulation of IκBα, MAPK, and STAT1 activities.
Effects on Growth and Osteogenic Differentiation of Mesenchymal Stem Cells by the Zinc-Added Sol-Gel Bioactive Glass Granules
Sun-Ae Oh,So-Hee Kim,Jong-Eun Won,Jung-Ju Kim
Journal of Tissue Engineering , 2010, DOI: 10.4061/2010/475260
Abstract:
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