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Search Results: 1 - 10 of 10141 matches for " Seung-Won Park "
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15-deoxy-Δ12,14-prostaglandin J2 Down-Regulates Activin-Induced Activin Receptor, Smad, and Cytokines Expression via Suppression of NF-κB and MAPK Signaling in HepG2 Cells
Seung-Won Park,Chunghee Cho,Byung-Nam Cho,Youngchul Kim,Tae Won Goo,Young Il Kim
PPAR Research , 2013, DOI: 10.1155/2013/751261
Abstract: 15-Deoxy- -prostaglandin J2 (15d-PGJ2) and activin are implicated in the control of apoptosis, cell proliferation, and inflammation in cells. We examined both the mechanism by which 15d-PGJ2 regulates the transcription of activin-induced activin receptors (ActR) and Smads in HepG2 cells and the involvement of the nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways in this regulation. Activin A (25?ng/mL) inhibited HepG2 cell proliferation, whereas 15d-PGJ2 (2?μM and 5?μM) had no effect. Activin A and 15d-PGJ2 showed different regulatory effects on ActR and Smad expression, NF-κB p65 activity and MEK/ERK phosphorylation, whereas they both decreased IL-6 production and increased IL-8 production. When co-stimulated with 15d-PGJ2 and activin, 15d-PGJ2 inhibited the activin-induced increases in ActR and Smad expression, and decreased activin-induced IL-6 production. However, it increased activin-induced IL-8 production. In addition, 15d-PGJ2 inhibited activin-induced NF-κB p65 activity and activin-induced MEK/ERK phosphorylation. These results suggest that 15d-PGJ2 suppresses activin-induced ActR and Smad expression, down-regulates IL-6 production, and up-regulates IL-8 production via suppression of NF-κB and MAPK signaling pathway in HepG2 cells. Regulation of ActR and Smad transcript expression and cytokine production involves NF-κB and the MAPK pathway via interaction with 15d-PGJ2/activin/Smad signaling. 1. Introduction Activins are either heterodimers or homodimers of inhibin β subunits (βAβA, βBβB, or βAβB) [1]. The biological activities of activins are mediated by receptor complexes that consist of 2 different activin serine/threonine kinase receptors (ActR), type I (ActR I) and type II (ActR II) [2]. Smad2 and Smad3 proteins are phosphorylated by specific activated type I serine/threonine kinase receptors. Formation of dimeric complexes leads to phosphorylation of Smad2 and Smad3, subsequent complex formation with Smad4, and regulation of activin-responsive genes [3, 4]. Smad7 functions as an inhibitor of transforming growth factor-β (TGF-β) family signaling, including activin signaling [5, 6]. Activin-responsive genes have been implicated in the control of homeostasis, development, proliferation, apoptosis, differentiation, and inflammation in diverse cellular systems [2]. 15-Deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) is a derivative of prostaglandin D2 and is a natural ligand of peroxisome proliferator-activated receptor-gamma (PPARγ), which is a transcriptional nuclear receptor [7, 8]. 15d-PGJ2 has a broad spectrum of
A low level of serum total testosterone is independently associated with nonalcoholic fatty liver disease
Sunmi Kim, Hyuktae Kwon, Jin-Ho Park, Belong Cho, Donghee Kim, Seung-Won Oh, Cheol Min Lee, Ho-Chun Choi
BMC Gastroenterology , 2012, DOI: 10.1186/1471-230x-12-69
Abstract: This study is a retrospective observational cross-sectional one of healthy Korean men and was conducted at the Seoul National University Hospital Healthcare System Gangnam Center. We used data obtained from 495 men who were at least 20?years of age and who had undergone blood testing, abdominal computed tomography, and ultrasonography. Multiple logistic regression analysis was used to explore the association of serum total testosterone levels with NAFLD.Men in the low serum testosterone quintile were at a higher risk for NAFLD than men in the highest serum testosterone quintile. After adjusting for age, smoking, diabetes, exercise, BMI, triglycerides, and high-density-lipoprotein cholesterol, subjects with serum testosterone levels in the lowest quintile had an odds ratio (OR) (95% confidence interval (CI)) of 5.12 (2.43–10.77) for NAFLD (p value, 0.0004). The inverse association between serum testosterone and NAFLD was attenuated by further adjustment for variables including VAT; however, it remained statistically significant (OR (95% CI): 4.52 (2.09–9.80) in the lowest quintile; p value=0.004).A low serum total testosterone level was independently associated with NAFLD. This report is the first one suggesting the association remains unchanged even after controlling for VAT and insulin resistance.
Standardized positive controls for detection of norovirus by reverse transcription PCR
Sung-Geun Lee, Soe-Hyun Lee, Seung-Won Park, Chang-Il Suh, Weon-Hwa Jheong, SeHwan Oh, Soon-Young Paik
Virology Journal , 2011, DOI: 10.1186/1743-422x-8-260
Abstract: In the current study, four types of RNA transcripts were produced from plasmids: norovirus GI-5 and GII-4 capsid regions with human rotavirus (VP7 gene derived) fragment insertions, and norovirus GI-6 and GII-4 capsid regions with hepatitis A virus (VP1/P2A gene derived) fragment insertions. These size-distinguishable products were used as positive controls under the RT-PCR assay conditions used to detect NoV in stool and groundwater samples. Their reliability and reproducibility was confirmed by multiple sets of experiments.These standardized products may contribute to the reliable and accurate diagnosis by RT-PCR of norovirus outbreaks, when conducted by laboratories located in different regions.Gastroenteritis, also known as "stomach flu", is a major public health concern and causes over 1.8 million deaths worldwide every year in children younger than five. Several studies and diagnostic analyses have shown that noroviruses (NoVs) are the leading cause of acute nonbacterial gastroenteritis. Although the gastroenteritis caused by NoVs is mild and of short duration, it affects persons of all ages and sometimes leads to death. Although severe illness is rare, complications related to dehydration can occur in very young and elderly individuals, and those with weakened immune systems. Depending on whether the dehydration is treated promptly, patients in these groups may face life-threatening risks. Therefore, the detection and monitoring of NoV is an important task for national public health agencies [1,2].Norovirus is a member of the Caliciviridae family and has been classified into five genogroups (GI to GV) based on capsid gene sequence homology. The positive-sense, single-stranded RNA genome sized 7.6 kb contains three open reading frames (ORFs) [3,4]. The NoVs that are the most common causative agents of human infection are in the GI and GII genogroups; each of these genogroups is further divided into 8 and 17 genotypes, respectively [4-6].When sensitive diagnost
Long Concept Query on Conceptual Taxonomies
Yi Zhang,Yanghua Xiao,Seung-won Hwang,Wei Wang
Computer Science , 2015,
Abstract: This paper studies the problem of finding typical entities when the concept is given as a query. For a short concept such as university, this is a well-studied problem of retrieving knowledge base such as Microsoft's Probase and Google's isA database pre-materializing entities found for the concept in Hearst patterns of the web corpus. However, we find most real-life queries are long concept queries (LCQs), such as top American private university, which cannot and should not be pre-materialized. Our goal is an online construction of entity retrieval for LCQs. We argue a naive baseline of rewriting LCQs into an intersection of an expanded set of composing short concepts leads to highly precise results with extremely low recall. Instead, we propose to augment the concept list, by identifying related concepts of the query concept. However, as such increase of recall often invites false positives and decreases precision in return, we propose the following two techniques: First, we identify concepts with different relatedness to generate linear orderings and pairwise ordering constraints. Second, we rank entities trying to avoid conflicts with these constraints, to prune out lowly ranked one (likely false positives). With these novel techniques, our approach significantly outperforms state-of-the-arts.
Iterative PSF Estimation and Its Application to Shift Invariant and Variant Blur Reduction
Seung-Won Jung,Byeong-Doo Choi,Sung-Jea Ko
EURASIP Journal on Advances in Signal Processing , 2009, DOI: 10.1155/2009/909636
Abstract: Among image restoration approaches, image deconvolution has been considered a powerful solution. In image deconvolution, a point spread function (PSF), which describes the blur of the image, needs to be determined. Therefore, in this paper, we propose an iterative PSF estimation algorithm which is able to estimate an accurate PSF. In real-world motion-blurred images, a simple parametric model of the PSF fails when a camera moves in an arbitrary direction with an inconsistent speed during an exposure time. Moreover, the PSF normally changes with spatial location. In order to accurately estimate the complex PSF of a real motion blurred image, we iteratively update the PSF by using a directional spreading operator. The directional spreading is applied to the PSF when it reduces the amount of the blur and the restoration artifacts. Then, to generalize the proposed technique to the linear shift variant (LSV) model, a piecewise invariant approach is adopted by the proposed image segmentation method. Experimental results show that the proposed method effectively estimates the PSF and restores the degraded images.
Efficient and scalable geometric hashing method for searching protein 3D structures
Gook-Pil Roh,Seung-won Hwang,Byoung-Kee Yi
Computer Science , 2011,
Abstract: As the structural databases continue to expand, efficient methods are required to search similar structures of the query structure from the database. There are many previous works about comparing protein 3D structures and scanning the database with a query structure. However, they generally have limitations on practical use because of large computational and storage requirements. We propose two new types of queries for searching similar sub-structures on the structural database: LSPM (Local Spatial Pattern Matching) and RLSPM (Reverse LSPM). Between two types of queries, we focus on RLSPM problem, because it is more practical and general than LSPM. As a naive algorithm, we adopt geometric hashing techniques to RLSPM problem and then propose our proposed algorithm which improves the baseline algorithm to deal with large-scale data and provide an efficient matching algorithm. We employ the sub-sampling and Z-ordering to reduce the storage requirement and execution time, respectively. We conduct our experiments to show the correctness and reliability of the proposed method. Our experiment shows that the true positive rate is at least 0.8 using the reliability measure.
Entity Suggestion by Example using a Conceptual Taxonomy
Yi Zhang,Yanghua Xiao,Seung-won Hwang,Haixun Wang,X. Sean Wang,Wei Wang
Computer Science , 2015,
Abstract: Entity suggestion by example (ESbE) refers to a type of entity acquisition query in which a user provides a set of example entities as the query and obtains in return some entities that best complete the concept underlying the given query. Such entity acquisition queries can be useful in many applications such as related-entity recommendation and query expansion. A number of ESbE query processing solutions exist in the literature. However, they mostly build only on the idea of entity co-occurrences either in text or web lists, without taking advantage of the existence of many web-scale conceptual taxonomies that consist of hierarchical isA relationships between entity-concept pairs. This paper provides a query processing method based on the relevance models between entity sets and concepts. These relevance models can be used to obtain the fine-grained concepts implied by the query entity set, and the entities that belong to a given concept, thereby providing the entity suggestions. Extensive evaluations with real data sets show that the accuracy of the queries processed with this new method is significantly higher than that of existing solutions.
Spatial Skyline Queries: An Efficient Geometric Algorithm
Wanbin Son,Mu-Woong Lee,Hee-Kap Ahn,Seung-won Hwang
Computer Science , 2009,
Abstract: As more data-intensive applications emerge, advanced retrieval semantics, such as ranking or skylines, have attracted attention. Geographic information systems are such an application with massive spatial data. Our goal is to efficiently support skyline queries over massive spatial data. To achieve this goal, we first observe that the best known algorithm VS2, despite its claim, may fail to deliver correct results. In contrast, we present a simple and efficient algorithm that computes the correct results. To validate the effectiveness and efficiency of our algorithm, we provide an extensive empirical comparison of our algorithm and VS2 in several aspects.
RNA-Seq Approach for Genetic Improvement of Meat Quality in Pig and Evolutionary Insight into the Substrate Specificity of Animal Carbonyl Reductases
Won Yong Jung, Seul Gi Kwon, Minky Son, Eun Seok Cho, Yuno Lee, Jae Hwan Kim, Byeong-Woo Kim, Da Hye Park, Jung Hye Hwang, Tae Wan Kim, Hwa Choon Park, Beom Young Park, Jong-Soon Choi, Kwang Keun Cho, Ki Hwa Chung, Young Min Song, Il Suk Kim, Sang Keun Jin, Doo Hwan Kim, Seung-Won Lee, Keun Woo Lee, Woo Young Bang, Chul Wook Kim
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0042198
Abstract: Changes in meat quality traits are strongly associated with alterations in postmortem metabolism which depend on genetic variations, especially nonsynonymous single nucleotide variations (nsSNVs) having critical effects on protein structure and function. To selectively identify metabolism-related nsSNVs, next-generation transcriptome sequencing (RNA-Seq) was carried out using RNAs from porcine liver, which contains a diverse range of metabolic enzymes. The multiplex SNV genotyping analysis showed that various metabolism-related genes had different nsSNV alleles. Moreover, many nsSNVs were significantly associated with multiple meat quality traits. Particularly, ch7:g.22112616A>G SNV was identified to create a single amino acid change (Thr/Ala) at the 145th residue of H1.3-like protein, very close to the putative 147th threonine phosphorylation site, suggesting that the nsSNV may affect multiple meat quality traits by affecting the epigenetic regulation of postmortem metabolism-related gene expression. Besides, one nonsynonymous variation, probably generated by gene duplication, led to a stop signal in porcine testicular carbonyl reductase (PTCR), resulting in a C-terminal (E281-A288) deletion. Molecular docking and energy minimization calculations indicated that the binding affinity of wild-type PTCR to 5α-DHT, a C21-steroid, was superior to that of C-terminal-deleted PTCR or human carbonyl reductase, which was very consistent with experimental data, reported previously. Furthermore, P284 was identified as an important residue mediating the specific interaction between PTCR and 5α-DHT, and phylogenetic analysis showed that P284 is an evolutionarily conserved residue among animal carbonyl reductases, which suggests that the C-terminal tails of these reductases may have evolved under evolutionary pressure to increase the substrate specificity for C21-steroids and facilitate metabolic adaptation. Altogether, our RNA-Seq revealed that selective nsSNVs were associated with meat quality traits that could be useful for successful marker-assisted selection in pigs and also represents a useful resource to enhance understanding of protein folding, substrate specificity, and the evolution of enzymes such as carbonyl reductase.
A New Human Perception-Based Over-Exposure Detection Method for Color Images
Yeo-Jin Yoon,Keun-Yung Byun,Dae-Hong Lee,Seung-Won Jung,Sung-Jea Ko
Sensors , 2014, DOI: 10.3390/s140917159
Abstract: To correct an over-exposure within an image, the over-exposed region (OER) must first be detected. Detecting the OER accurately has a significant effect on the performance of the over-exposure correction. However, the results of conventional OER detection methods, which generally use the brightness and color information of each pixel, often deviate from the actual OER perceived by the human eye. To overcome this problem, in this paper, we propose a novel method for detecting the perceived OER more accurately. Based on the observation that recognizing the OER in an image is dependent on the saturation sensitivity of the human visual system (HVS), we detect the OER by thresholding the saturation value of each pixel. Here, a function of the proposed method, which is designed based on the results of a subjective evaluation on the saturation sensitivity of the HVS, adaptively determines the saturation threshold value using the color and the perceived brightness of each pixel. Experimental results demonstrate that the proposed method accurately detects the perceived OER, and furthermore, the over-exposure correction can be improved by adopting the proposed OER detection method.
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