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Search Results: 1 - 10 of 5709 matches for " Heon-Sang Jeong "
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Anti-inflammatory and arthritic effects of thiacremonone, a novel sulfurcompound isolated from garlic via inhibition of NF-κB
Jung Ban, Ju Oh, Tae Kim, Dae Kim, Heon-Sang Jeong, Sang Han, Jin Hong
Arthritis Research & Therapy , 2009, DOI: 10.1186/ar2819
Abstract: The anti-inflammatory and arthritis effects of thiacremone in in vivo were investigated in 12-O-tetradecanoylphorbol-13-acetate-induced ear edema, carrageenan and mycobacterium butyricum-induced inflammatory and arthritis models. Lipopolysaccharide-induced nitric oxide (NO) production was determined by Griess method. The DNA binding activity of NF-κB was investigated by electrophoretic mobility shift assay. NF-κB and inducible nitric oxide synthetase (iNOS) transcriptional activity was determined by luciferase assay. Expression of iNOS and cyclooxygenase-2 (COX-2) was determined by western blot.The results showed that topical application of thiacremonone (1 or 2 μg/ear) suppressed the 12-O-tetradecanoylphorbol-13-acetate-induced (1 μg/ear) ear edema. Thiacremonone (1-10 mg/kg) administered directly into the plantar surface of hind paw also suppressed the carrageenan (1.5 mg/paw) and mycobacterium butyricum (2 mg/paw)-induced inflammatory and arthritic responses as well as expression of iNOS and COX-2, in addition to NF-κB DNA-binding activity. In further in vitro study, thiacremonone (2.5-10 μg/ml) inhibited lipopolysaccharide (LPS, 1 μg/ml)-induced nitric oxide (NO) production, and NF-κB transcriptional and DNA binding activity in a dose dependent manner. The inhibition of NO by thiacremonone was consistent with the inhibitory effect on LPS-induced inducible nitric oxide synthase (iNOS) and COX-2 expression, as well as iNOS transcriptional activity. Moreover, thiacremonone inhibited LPS-induced p50 and p65 nuclear translocation, resulting in an inhibition of the DNA binding activity of the NF-κB. These inhibitory effects on NF-κB activity and NO generation were suppressed by reducing agents dithiothreitol (DTT) and glutathione, and were abrogated in p50 (C62S)-mutant cells, suggesting that the sulfhydryl group of NF-κB molecules may be a target of thiacremonone.The present results suggested that thiacremonone exerted its anti-inflammatory and anti-arthritic propert
Inhibitory effect of a tyrosine-fructose Maillard reaction product, 2,4-bis(p-hydroxyphenyl)-2-butenal on amyloid-β generation and inflammatory reactions via inhibition of NF-κB and STAT3 activation in cultured astrocytes and microglial BV-2 cells
Young-Jung Lee, Dong-Young Choi, Im Seup Choi, Jin-Yi Han, Heon-Sang Jeong, Sang Bae Han, Ki-Wan Oh, Jin Tae Hong
Journal of Neuroinflammation , 2011, DOI: 10.1186/1742-2094-8-132
Abstract: Cultured astrocytes and microglial BV-2 cells were treated with LPS (1 μg/ml) for 24 h, in the presence (1, 2, 5 μM) or absence of 2,4-bis(p-hydroxyphenyl)-2-butenal, and harvested. We performed molecular biological analyses to determine the levels of inflammatory and amyloid-related proteins and molecules, cytokines, Aβ, and secretases activity. Nuclear factor-kappa B (NF-κB) DNA binding activity was determined using gel mobility shift assays.We found that 2,4-bis(p-hydroxyphenyl)-2-butenal (1, 2, 5 μM) suppresses the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) as well as the production of nitric oxide (NO), reactive oxygen species (ROS), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) in LPS (1 μg/ml)-stimulated astrocytes and microglial BV-2 cells. Further, 2,4-bis(p-hydroxyphenyl)-2-butenal inhibited the transcriptional and DNA binding activity of NF-κB--a transcription factor that regulates genes involved in neuroinflammation and amyloidogenesis via inhibition of IκB degradation as well as nuclear translocation of p50 and p65. Consistent with the inhibitory effect on inflammatory reactions, 2,4-bis(p-hydroxyphenyl)-2-butenal inhibited LPS-elevated Aβ42 levels through attenuation of β- and γ-secretase activities. Moreover, studies using signal transducer and activator of transcription 3 (STAT3) siRNA and a pharmacological inhibitor showed that 2,4-bis(p-hydroxyphenyl)-2-butenal inhibits LPS-induced activation of STAT3.These results indicate that 2,4-bis(p-hydroxyphenyl)-2-butenal inhibits neuroinflammatory reactions and amyloidogenesis through inhibition of NF-κB and STAT3 activation, and suggest that 2,4-bis(p-hydroxyphenyl)-2-butenal may be useful for the treatment of neuroinflammatory diseases like Alzheimer's disease.Alzheimer's disease (AD) is an age-related neurodegenerative disease characterized by the accumulation of beta amyloid (Aβ), an insoluble peptide deposited extracellularly in the brain, causing s
3D N=2 massive super Yang-Mills and membranes/D2-branes in a curved background
Seungjoon Hyun,Jeong-Hyuck Park,Sang-Heon Yi
Physics , 2003, DOI: 10.1088/1126-6708/2003/03/004
Abstract: We present a three dimensional novel massive N=2 super Yang-Mills action as a low energy effective worldvolume description of the D2-branes on a pp-wave. The action contains the Myers term, mass terms for three Higgs, and terms mixing the electric fields with other two Higgs. We derive the action in three different ways, from the M-theory matrix model, from the supermembrane action, and from the Dirac-Born-Infeld action. We verify the consistent mutual agreement and comment how each approach is complementary to another. In particular, we give the eleven dimensional geometric interpretation of the vacua in the worldvolume theory as the membranes tilted to the eleventh direction with the giant gravitons around.
Noncritical Einstein-Weyl Gravity and the AdS/CFT Correspondence
Seungjoon Hyun,Wooje Jang,Jaehoon Jeong,Sang-Heon Yi
Physics , 2011, DOI: 10.1007/JHEP01(2012)054
Abstract: We explore four-dimensional Einstein-Weyl gravity and supergravity on anti-de Sitter spacetime. For a specific range of the coupling with appropriate boundary conditions, we show the effective equivalence of the theory with Einstein gravity and AdS supergravity at the quadratic Lagrangian level. Furthermore we show that these equivalences can be promoted to the full nonlinear level. We also show that the similar behavior holds for the generalized Gibbons-Hawking terms. From this we find that the correlation functions in the dual conformal field theory of Einstein-Weyl gravity and supergravity can be readily read off from corresponding ones from Einstein gravity and AdS supergravity. We also give comments on some issues in critical gravity and supergravity as well as conformal gravity and supergravity.
On Classical Equivalence Between Noncritical and Einstein Gravity : The AdS/CFT Perspectives
Seungjoon Hyun,Wooje Jang,Jaehoon Jeong,Sang-Heon Yi
Physics , 2012, DOI: 10.1007/JHEP04(2012)030
Abstract: We find that noncritical gravity, a special class of higher derivative gravity, is classically equivalent to Einstein gravity at the full nonlinear level. We obtain the viscosity-to-entropy ratio and the second order transport coefficients of the dual fluid of noncritical gravity to all orders in the coupling of higher derivative terms. We also compute the holographic entanglement entropy in the dual CFT of noncritical gravity. All these results confirm the nonlinear equivalence between noncritical gravity and Einstein gravity at the classical level.
Fake Supersymmetry and Extremal Black Holes
Seungjoon Hyun,Jaehoon Jeong,Sang-Heon Yi
Physics , 2012, DOI: 10.1007/JHEP03(2013)020
Abstract: We derive the BPS type of first order differential equations for the rotating black hole solutions in the three-dimensional Einstein gravity coupled minimally with a self-interacting scalar field, using fake supersymmetry formalism. It turns out that the formalism is not complete and should be augmented by an additional equation to imply the full equations of motion. We identify this additional equation as a constraint by using an effective action method. By computing the renormalized boundary stress tensor, we obtain the mass and angular momentum of the black hole solutions of these first order equations and confirm that they saturate the BPS bound.
Seoul National University Renal Stone Complexity Score for Predicting Stone-Free Rate after Percutaneous Nephrolithotomy
Chang Wook Jeong, Jin-Woo Jung, Woo Heon Cha, Byung Ki Lee, Sangchul Lee, Seong Jin Jeong, Sung Kyu Hong, Seok-Soo Byun, Sang Eun Lee
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0065888
Abstract: Objectives Currently, no standardized method is available to predict success rate after percutaneous nephrolithotomy. We devised and validated the Seoul National University Renal Stone Complexity (S-ReSC) scoring system for predicting the stone-free rate after single-tract percutaneous nephrolithotomy (sPCNL). Patients and Methods The data of 155 consecutive patients who underwent sPCNL were retrospectively analyzed. Preoperative computed tomography images were reviewed. The S-ReSC score was assigned from 1 to 9 based on the number of sites involved in the renal pelvis (#1), superior and inferior major calyceal groups (#2–3), and anterior and posterior minor calyceal groups of the superior (#4–5), middle (#6–7), and inferior calyx (#8–9). The inter- and intra-observer agreements were accessed using the weighted kappa (κ). The stone-free rate and complication rate were evaluated according to the S-ReSC score. The predictive accuracy of the S-ReSC score was assessed using the area under the receiver operating characteristic curve (AUC). Results The overall SFR was 72.3%. The mean S-ReSC score was 3.15±2.1. The weighted kappas for the inter- and intra-observer agreements were 0.832 and 0.982, respectively. The SFRs in low (1 and 2), medium (3 and 4), and high (5 or higher) S-ReSC scores were 96.0%, 69.0%, and 28.9%, respectively (p<0.001). The predictive accuracy was very high (AUC 0.860). After adjusting for other variables, the S-ReSC score was still a significant predictor of the SFR by multiple logistic regression. The complication rates were increased to low (18.7%), medium (28.6%), and high (34.2%) (p = 0.166). Conclusions The S-ReSC scoring system is easy to use and reproducible. This score accurately predicts the stone-free rate after sPCNL. Furthermore, this score represents the complexity of surgery.
A Study of Changes in Risk Appetite in the Stock Market and the Housing Market before and after the Global Financial Crisis in 2008 Using the vKOSPI  [PDF]
Jin Yong Yang, Sang-Heon Lee
Modern Economy (ME) , 2013, DOI: 10.4236/me.2013.411077
Abstract: This study analyzes the empirical relationship between the vKOSPI, which is the Korean VIX (implied volatility index), and the housing market (rent1-to-house price ratio) based on monthly data from January 2003 to November 2012. The data were divided into two parts before and after the global financial crisis in 2008 and were analyzed by using the Vector Autoregressive (VAR) Model. The research results show that the influence of vKOSPI on the housing market changes from symmetric to asymmetric since the global financial crisis in 2008. Before the global crisis in 2008, the influence of the vKOSPI on the house price index and rent index is almost the same, so the influence on the rent-to-house price ratio is not statistically significant. However, since the global crisis in 2008, the influence of the vKOSPI on the two prices has changed asymmetrically and the influence on the rent-to-house price ratio was statistically significant. Second, the influence of the vKOSPI fluctuation on house sale prices and rent is shown differently according to the rise/fall of the vKOSPI. In the event of the vKOSPI rising, house prices would fall greatly. On the other hand, in the event of the vKOSPI falling, the rise in housing prices is relatively small. This means that while the boosted sentiment of investors in the stock market is not transferred to the housing sales market, the aggravated sentiment of investors affects the housing sales market easily. In conclusion, the uncertainty has been represented in the vKOSPI and the preference for risky assets has an asymmetrical influence on the market dependent upon the kind of market. We suspect that this is caused by complex factors including shrinking expectations for future house prices.

Born-Infeld Type Extension of (Non-)Critical Gravity
Sang-Heon Yi
Physics , 2012, DOI: 10.1103/PhysRevD.86.024023
Abstract: We consider the Born-Infeld type extension of (non-)critical gravity which is higher curvature gravity on Anti de-Sitter space with specific combinations of scalar curvature and Ricci tensor. This theory may also be viewed as a natural extension of three-dimensional Born-Infeld new massive gravity to arbitrary dimensions. We show that this extension is consistent with holographic $c$-theorem and scalar graviton modes are absent in this theory. After showing that ghost modes in the theory can be truncated consistently by appropriate boundary conditions, we argue that the theory is classically equivalent to Einstein gravity at the non-linear level. Black hole solutions are discussed in the view point of the full non-linear classical equivalence between the theory and Einstein gravity. Holographic entanglement entropy in the theory is also briefly commented on.
Broad Energy HPGe Gamma Spectrometry for Dose Rate Estimation for Trapped Charge Dating
Jeong Hee Han,Jeong-Heon Choi
Journal of Analytical Science & Technology , 2010,
Abstract: Gamma-ray spectrometry has been widely used in various environmental and natural sciences by its ability to determine the concentrations of each radionuclide of the samples, and also because of the easiness in sample preparation and measurement procedures. Recently, its applicability is being extended for Quaternary geochronology, by providing information on the rate of energy absorbed by phosphor minerals (i.e. dose rate) used in trapped charge dating methods. To measure the radionuclides emitting low energy gamma ray (particularly, 210Pb and 234Th), which are subjected to be easily absorbed by detector-cryostat materials and sample itself, various HPGe detectors have been developed, because these detectors have high resolution capacity and are relatively easy for maintenance. In this paper, we review the characteristics of p-type coaxial HPGe, well-type HPGe and broad energy HPGe (BEGe) gamma-ray detector, and these are compared with each other, particularly with a view to establishing the most appropriate measurement procedure for estimating the dose rate for trapped charge dating methods. Also various calibration factors to analyse the low-level environmental samples are discussed. Especially self-absorption correction method using sample weight is suggested.
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