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Search Results: 1 - 10 of 19696 matches for " Byoung-Joon Song "
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PPAR/RXR Regulation of Fatty Acid Metabolism and Fatty Acid -Hydroxylase (CYP4) Isozymes: Implications for Prevention of Lipotoxicity in Fatty Liver Disease
James P. Hardwick,Douglas Osei-Hyiaman,Homer Wiland,Mohamed A. Abdelmegeed,Byoung-Joon Song
PPAR Research , 2009, DOI: 10.1155/2009/952734
Abstract: Fatty liver disease is a common lipid metabolism disorder influenced by the combination of individual genetic makeup, drug exposure, and life-style choices that are frequently associated with metabolic syndrome, which encompasses obesity, dyslipidemia, hypertension, hypertriglyceridemia, and insulin resistant diabetes. Common to obesity related dyslipidemia is the excessive storage of hepatic fatty acids (steatosis), due to a decrease in mitochondria -oxidation with an increase in both peroxisomal -oxidation, and microsomal -oxidation of fatty acids through peroxisome proliferator activated receptors (PPARs). How steatosis increases PPAR activated gene expression of fatty acid transport proteins, peroxisomal and mitochondrial fatty acid -oxidation and -oxidation of fatty acids genes regardless of whether dietary fatty acids are polyunsaturated (PUFA), monounsaturated (MUFA), or saturated (SFA) may be determined by the interplay of PPARs and HNF4 with the fatty acid transport proteins L-FABP and ACBP. In hepatic steatosis and steatohepatitis, the -oxidation cytochrome P450 CYP4A gene expression is increased even with reduced hepatic levels of PPAR. Although numerous studies have suggested the role ethanol-inducible CYP2E1 in contributing to increased oxidative stress, Cyp2e1-null mice still develop steatohepatitis with a dramatic increase in CYP4A gene expression. This strongly implies that CYP4A fatty acid -hydroxylase P450s may play an important role in the development of steatohepatitis. In this review and tutorial, we briefly describe how fatty acids are partitioned by fatty acid transport proteins to either anabolic or catabolic pathways regulated by PPARs, and we explore how medium-chain fatty acid (MCFA) CYP4A and long-chain fatty acid (LCFA) CYP4F -hydroxylase genes are regulated in fatty liver. We finally propose a hypothesis that increased CYP4A expression with a decrease in CYP4F genes may promote the progression of steatosis to steatohepatitis.
Zidovudine (AZT) and Hepatic Lipid Accumulation: Implication of Inflammation, Oxidative and Endoplasmic Reticulum Stress Mediators
Atrayee Banerjee, Mohamed A. Abdelmegeed, Sehwan Jang, Byoung-Joon Song
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0076850
Abstract: The clinical effectiveness of Zidovudine (AZT) is constrained due to its side-effects including hepatic steatosis and toxicity. However, the mechanism(s) of hepatic lipid accumulation in AZT-treated individuals is unknown. We hypothesized that AZT-mediated oxidative and endoplasmic reticulum (ER) stress may play a role in the AZT-induced hepatic lipid accumulation. AZT treatment of C57BL/6J female mice (400 mg/day/kg body weight, i.p.) for 10 consecutive days significantly increased hepatic triglyceride levels and inflammation. Markers of oxidative stress such as protein oxidation, nitration, glycation and lipid peroxidation were significantly higher in the AZT-treated mice compared to vehicle controls. Further, the levels of ER stress marker proteins like GRP78, p-PERK, and p-eIF2α were significantly elevated in AZT-treated mice. The level of nuclear SREBP-1c, a transcription factor involved in fat synthesis, was increased while significantly decreased protein levels of phospho-acetyl-CoA carboxylase, phospho-AMP kinase and PPARα as well as inactivation of 3-keto-acyl-CoA thiolase in the mitochondrial fatty acid β-oxidation pathway were observed in AZT-exposed mice compared to those in control animals. Collectively, these data suggest that elevated oxidative and ER stress plays a key role, at least partially, in lipid accumulation, inflammation and hepatotoxicity in AZT-treated mice.
Induction of Neuronal Death by Microglial AGE-Albumin: Implications for Alzheimer’s Disease
Kyunghee Byun, Enkhjaigal Bayarsaikhan, Daesik Kim, Chae Young Kim, Inhee Mook-Jung, Sun Ha Paek, Seung U. Kim, Tadashi Yamamoto, Moo-Ho Won, Byoung-Joon Song, Young Mok Park, Bonghee Lee
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0037917
Abstract: Advanced glycation end products (AGEs) have long been considered as potent molecules promoting neuronal cell death and contributing to neurodegenerative disorders such as Alzheimer’s disease (AD). In this study, we demonstrate that AGE-albumin, the most abundant AGE product in human AD brains, is synthesized in activated microglial cells and secreted into the extracellular space. The rate of AGE-albumin synthesis in human microglial cells is markedly increased by amyloid-β exposure and oxidative stress. Exogenous AGE-albumin upregulates the receptor protein for AGE (RAGE) and augments calcium influx, leading to apoptosis of human primary neurons. In animal experiments, soluble RAGE (sRAGE), pyridoxamine or ALT-711 prevented Aβ-induced neuronal death in rat brains. Collectively, these results provide evidence for a new mechanism by which microglial cells promote death of neuronal cells through synthesis and secretion of AGE-albumin, thereby likely contributing to neurodegenerative diseases such as AD.
Intrusion-Tolerant Jini Service Architecture for Integrating Security and Survivability Support in DSN
Sung-Ki Kim,Byung-Gyu Kim,Byoung-Joon Min
International Journal of Distributed Sensor Networks , 2014, DOI: 10.1155/2014/695240
Abstract: Ubiquitous service environment based on DSN (distributed sensor networks) is poor in reliability of connection and has a high probability that the intrusion and the system failure may occur. In this paper, we propose an intrusion-tolerant Jini service architecture for integrating security and survivability support in order to provide end users with Jini services having a persistent state in ubiquitous environments. The proposed architecture is able to protect Jini service delivery not only from faults such as network partitioning or server crash but also from attacks exploiting flaws. It is designed to provide performance enough to show a low response latency so as to support seamless service usage. Through the experiment on a testbed, we have confirmed that the architecture is able to provide high security and availability at the level that the degradation of services quality is ignorable. 1. Introduction Jini [1], also called Apache River [2], is a java-based middleware supporting share of resources such as ubiquitous devices and software on networks while it copes with the heterogeneity of the lower levels such as the various types of devices or communication protocols. A service that can cause us to use these pervasive resources is called the ubiquitous service. Jini provides a mechanism that discovers available services through the lookup services and make a connection to the services that clients requested. It is important to enhance the survivability of the ubiquitous service because we live depending on the ubiquitous service environment providing valuable services through pervasive use of computation in everyday experiences. However, the networked systems in the environment are apt to be partitioned due to a poor reliability of connection and have a high probability that the intrusion against a system providing services and the failure of the services may happen [3]. Therefore, it is very important to guarantee that the legitimate users make use of trustable services without discontinuance or obstacle of the services they are enjoying. The standard Jini has two main problems in regard to these requirements. First, the Jini does not support building of fault tolerance services to mask the failure of services leased for resource use [4]. Second, the Jini has an insufficient security mechanism that cannot support dynamic trust establishment within a Jini system [5]. The former problem means that clients cannot keep using their service they are enjoying persistently when a Jini system is partitioned due to both communication link failures and
On the Delay Scaling Laws of Cache Networks
Boram Jin,Se-Young Yun,Deawoo Kim,Jinwoo Shin,Yung Yi,Seongik Hong,Byoung-Joon,Lee
Computer Science , 2013,
Abstract: The Internet is becoming more and more content-oriented, where one of main components in content-oriented Internet architectures is network caching. Despite a surge of extensive use of network cashing in the current and future Internet architectures, analysis on the performance of general cache networks are still quite limited due to complex inter-plays among various components and thus analytical intractability. We study asymptotic delay performance of cache networks, in particular, focusing on the impact of heterogeneous content popularities and nodes' geometric `importances' in caching policies. Our theoretical findings provide useful engineering implications such as when and how various factors have impact on caching performance, and we provide extensive simulation results on the real Internet topology.
A proof of some Sch tzenberger-type results for Eulerian paths and circuits on digraphs
Byoung-Song Chwe
International Journal of Mathematics and Mathematical Sciences , 1994, DOI: 10.1155/s0161171294000736
Abstract: This paper shows that the number of even Eulerian paths equals the number of odd Eulerian paths when the number of arcs is at least twice the number of vertices of a digraph.
Distributed Sensor Network Based on RFID System for Localization of Multiple Mobile Agents  [PDF]
Byoung-Suk Choi, Joon-Woo Lee, Ju-Jang Lee, Kyoung-Taik Park
Wireless Sensor Network (WSN) , 2011, DOI: 10.4236/wsn.2011.31001
Abstract: This paper presents a distributed wireless sensor network for multiple mobile agents localization. Localization of mobile agents, such as mobile robots, humans, and moving objects, in an indoor space is essential for robot-robot interaction (RRI) and human-robot interaction (HRI). The standard localization system, which is based on sensors installed in the robot body, is not suitable for multiple agents. Therefore, the concept of sensor network, which uses wireless sensors distributed in a specified space, is used in this study. By analyzing related studies, two solutions are proposed for the localization of mobile agents including humans: a new hardware system and a new software algorithm. The first solution focuses on the architectural design of the wireless sensor network for multiple agent localization. A passive RFID system is used, and then the architecture of the sensor network is adapted to suit the target system. The second solution centers on a localization algorithm based on the sensor network. The proposed localization algorithm improves the accuracy in the multiple agent localization system. The algorithm uses the displacement conditions of the mobile agents and the recognition changes between the RFID tags and RFID reader. Through experiments using a real platform, the usefulness of the proposed system is verified.
Atypical primary meningioma in the nasal septum with malignant transformation and distant metastasis
Byoung Joon Baek, Ji Hye Lee, Jae Min Shin, Chi Kyou Lee, Koen Hyeong Lee
BMC Cancer , 2012, DOI: 10.1186/1471-2407-12-275
Abstract: A 44-year-old male presented with a 2-month history of left-side nasal obstruction and frequent episodes of epistaxis. A friable mass originating from the nasal septum was resected completely via an endoscopic endonasal approach. According to WHO criteria, the tumor was diagnosed as an atypical meningioma radiologically and histopathologically. Two years later, a tumor recurred at the primary site with the same histopathological findings, and the patient was given local external radiotherapy (6840?cGy in 38 fractions). Two months after this local recurrence, a left anterior chest wall mass and a left parietal area scalp mass were observed. The subcutaneous mass was resected and showed histological evidence of malignant transformation. Several months after the last operation, the patient died.We describe the clinical, radiological, and bio-pathological features of this unique case and review the literature on atypical PEMs originating in the nasal septum. To our knowledge, this is the first reported case of an atypical PEM originating from the nasal septum that recurred with malignant transformation and extracranial metastasis.
Molecular Evidence of Lateral Gene Transfer in rpoB Gene of Mycobacterium yongonense Strains via Multilocus Sequence Analysis
Byoung-Jun Kim, Seok-Hyun Hong, Yoon-Hoh Kook, Bum-Joon Kim
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0051846
Abstract: Recently, a novel species, Mycobacterium yongonense (DSM 45126T), was introduced and while it is phylogenetically related to Mycobacterium intracellulare, it has a distinct RNA polymerase β-subunit gene (rpoB) sequence that is identical to that of Mycobacterium parascrofulaceum, which is a distantly related scotochromogen, which suggests the acquisition of the rpoB gene via a potential lateral gene transfer (LGT) event. The aims of this study are to prove the presence of the LGT event in the rpoB gene of the M. yongonense strains via multilocus sequence analysis (MLSA). In order to determine the potential of an LGT event in the rpoB gene of the M. yongonense, the MLSA based on full rpoB sequences (3447 or 3450 bp) and on partial sequences of five other targets [16S rRNA (1383 or 1395 bp), hsp65 (603 bp), dnaJ (192 bp), recA (1053 bp), and sodA (501 bp)] were conducted. Incongruences between the phylogenetic analysis of the full rpoB and the five other genes in a total of three M. yongonense strains [two clinical strains (MOTT-12 and MOTT-27) and one type strain (DSM 45126T)] were observed, suggesting that rpoB gene of three M. yongonense strains may have been acquired very recently via an LGT event from M. parascrofulaceum, which is a distantly related scotochromogen.
BER-Based Physical Layer Security with Finite Codelength: Combining Strong Converse and Error Amplification
Il-Min Kim,Byoung-Hoon Kim,Joon Kui Ahn
Mathematics , 2014,
Abstract: A bit error rate (BER)-based physical layer security approach is proposed for finite blocklength. For secure communication in the sense of high BER, the information-theoretic strong converse is combined with cryptographic error amplification achieved by substitution permutation networks (SPNs) based on confusion and diffusion. For discrete memoryless channels (DMCs), an analytical framework is provided showing the tradeoffs among finite blocklength, maximum/minimum possible transmission rates, and BER requirements for the legitimate receiver and the eavesdropper. Also, the security gap is analytically studied for Gaussian channels and the concept is extended to other DMCs including binary symmetric channels (BSCs) and binary erasure channels (BECs). For fading channels, the transmit power is optimized to minimize the outage probability of the legitimate receiver subject to a BER threshold for the eavesdropper.
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