TLR3-mediated signal induces proinflammatory cytokine and chemokine gene expression in astrocytes: Differential signaling mechanisms of TLR3-induced IP-10 and IL-8 gene expression

Park, Chanhee,Lee, Soojin,Cho, Ik-Hyun,Lee, Hyun Kyoung,Kim, Donghoon,Choi, Se-Young,Oh, Seog Bae,Park, Kyungpyo,Kim, Joong Soo,Lee, Sung Joong Wiley Subscription Services, Inc., A Wiley Company 2006 GLIA Vol.53 No.3

<P>Viral infection is one of the leading causes of brain encephalitis and meningitis. Recently, it was reported that Toll-like receptor-3 (TLR3) induces a double-stranded RNA (dsRNA)-mediated inflammatory signal in the cells of the innate immune system, and studies suggested that dsRNA may induce inflammation in the central nervous system (CNS) by activating the CNS-resident glial cells. To explore further the connection between dsRNA and inflammation in the CNS, we have studied the effects of dsRNA stimulation in astrocytes. Our results show that the injection of polyinosinic-polycytidylic acid (poly(I:C)), a synthetic dsRNA, into the striatum of the mouse brain induces the activation of astrocytes and the expression of TNF-α, IFN-β, and IP-10. Stimulation with poly(I:C) also induces the expression of these proinflammatory genes in primary astrocytes and in CRT-MG, a human astrocyte cell line. Furthermore, our studies on the intracellular signaling pathways reveal that poly(I:C) stimulation activates IκB kinase (IKK), extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) in CRT-MG. Pharmacological inhibitors of nuclear factor-κB (NF-κB), JNK, ERK, glycogen synthase kinase-3β (GSK-3β), and dsRNA-activated protein kinase (PKR) inhibit the expression of IL-8 and IP-10 in astrocytes, indicating that the activation of these signaling molecules is required for the TLR3-mediated chemokine gene induction. Interestingly, the inhibition of PI3 kinase suppressed the expression of IP-10, but upregulated the expression of IL-8, suggesting differential roles for PI3 kinase, depending on the target genes. These data suggest that the TLR3 expressed on astrocytes may initiate an inflammatory response upon viral infection in the CNS. © 2005 Wiley-Liss, Inc.</P>

Genetic variation through Dissociation (Ds) insertional mutagenesis system for rice in Korea: progress and current status

Park, Dong-Soo,Park, Soo-Kwon,Han, Sang-Ik,Wang, Hoe-Jeong,Jun, Nam-Soo,Manigbas, Norvie L.,Woo, Young-Min,Ahn, Byoung-Ohg,Yun, Doh-Won,Yoon, Ung-Han,Kim, Yong-Hwan,Lee, Myung-Chul,Kim, Doh-Hoon,Nam, Springer-Verlag 2009 Molecular breeding Vol.24 No.1

Reception Power Estimation Using Transmitter Identification Signal for Single Frequency Network

Sung Ik Park,Heung Mook Kim,Wangrok Oh IEEE 2009 IEEE transactions on broadcasting Vol.55 No.3

<P>In a single frequency network (SFN) based on the Advanced Television Systems Committee (ATSC) terrestrial digital television (DTV) system, receivers inevitably suffer from the interference generated by using the same frequency among multiple transmitters or repeaters. The amount of the interference can be handled by adjusting transmit power and time of each transmitter and repeater. Hence, it is crucial to estimate the individual reception power from each transmitter or repeater at the given point of interest. This paper presents an efficient method to estimate the individual reception power from each transmitter or repeater. The field test results are provided to evaluate the proposed method. The proposed method exploits the transmitter identification (TxID) signals which are embedded in existing 8-VSB signals.</P>

A Collagen/Smooth Muscle Cell-Incorporated Elastic Scaffold for Tissue-Engineered Vascular Grafts

Park, In Su,Kim, Sang-Heon,Kim, Young Ha,Kim, Ik Hwan,Kim, Soo Hyun Informa UK (TaylorFrancis) 2009 Journal of Biomaterials Science. Polymer Edition Vol.20 No.11

<P>Biodegradable tubular scaffolds have been developed for vascular graft application. This study was focused to improve the adhesion and proliferation of vascular smooth muscle cells (SMCs) in a tubular scaffold. Tubular scaffolds (ID 4 mm, OD 6 mm) were fabricated from a biodegradable elastic polymer, poly(L-lactide-co-epsilon-caprolactone) (PLCL) (50:50, M(n) 1.58 x 10(5)), by an extrusion/particulate leaching method. SMCs suspended in a collagen solution were infiltrated in tubular PLCL scaffolds under vacuum and incubated for 1 h at 37 degrees C to form a collagenous gel. Results from SEM image analysis showed that collagen was infiltrated into the inside of the scaffolds. Cell adhesion and proliferation rate increased in collagen/SMC-incorporated tubular PLCL scaffolds as compared with the scaffolds in which only SMCs were seeded. From SEM image and histological analysis, we further found that SMCs grew on the inside as well as on the surface of collagen/SMCs-incorporated scaffolds and the cells continued to grow as a monolayer on collagen fibers. In particular, cell proliferation and elastin contents were the highest in a PLCL scaffold with 50-100 microm pore size than any other scaffolds used in this experiment. A collagen/SMC-incorporated PLCL scaffold may support SMC growth and functions and can be used as a scaffold for tissue engineering to facilitate small-diameter vascular-tissue formation.</P>

An Efficient Receiver Structure for Robust Data Transmission using TxID Signal in the ATSC DTV System

Park, Sung, Ik,Kim, Heung, Mook,Wang, Xianbin,Wu, Yiyan,Oh, Wangrok IEEE 2010 IEEE transactions on consumer electronics Vol.56 No.2

<P>In a single frequency network (SFN) for Advanced Television Systems Committee (ATSC) terrestrial digital television (DTV) system, the interferences due to the multiple transmitters and/or repeaters using same frequency is inevitable. This interference problem can be solved by adjusting transmit power and time of each transmitter and repeater within a SFN. To assist this process, a transmitter identification (TxID) signal, which is embedded in the transmit signal from each transmitter or repeater, is recommended in the ATSC terrestrial DTV system. In this paper, we investigate the previous proposed robust data transmission schemes using the TxID signal and propose an efficient receiver structure for detection of the embedded data in TxID signals. Based on the laboratory test, we verify that the proposed scheme offers an additional reliable communication link supporting up to 160 bps data rate, which is at least 13 dB robust compared to the conventional DTV system</P>

Long Range Ultrasonic Guided Wave Technique for Inspection of Pipes

Park, Ik Keun,Kim, Yong Kwon,Kim, Hyun Mook,Song, Won Joon,Cho, Yong Sang Trans Tech Publications, Ltd. 2006 Key Engineering Materials Vol.321 No.-

<P>Conventional non-destructive techniques for inspection of weld in pipelines require significant test time and high cost. In this paper, a study in the application of ultrasonic guided waves to long range inspection of the pipeline is presented. The characteristics and setup of a long range guided wave inspection system and experimental results in pipes of various diameters are introduced. The experimental results in mock-up pipes with cluster type defects show that the limit of detectable wall thickness reduction with this guided wave system is 2~3% in the pipe cross section area and the wall thickness reduction of 5% in cross section area can be detected when actual detection level is used. Therefore, the applicability of the ultrasonic guided wave technique to long range pipeline inspection for wall thickness reduction is verified.</P>

Antioxidative activities of white rose flower extract and pharmaceutical advantages of its hexane fraction via free radical scavenging effects

Park, Dongsun,Jeon, Jeong Hee,Kwon, Sang-Chul,Shin, Sunhee,Jang, Ja Young,Jeong, Heon Sang,Lee, Do Ik,Kim, Yun-Bae,Joo, Seong Soo Canadian Science Publishing 2009 Biochemistry and cell biology Vol.87 No.6

<P> In this study, we determined the antioxidant activities of two different solvent fractions(butanol and hexane) obtained from white Rosa rugosa flowers by employing various assays such as 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH), 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, and nitric oxide (NO) scavenging and inhibition activity in S-nitroso-N-acetylpenicillamine (SNAP) in the RAW264.7 model. In addition, more advanced antioxidant assays were conducted, including lipid peroxidation, hydroxyl radical-mediated oxidation, DNA fragmentation, apoptosis, and cell growth. The results revealed that the hexane fraction, which contained a significant amount of polyphenols and volatile components, had excellent antioxidant potency and could scavenge free radicals of DPPH and ABTS. Interestingly, the hexane fraction inhibited lipid peroxidation to almost the same degree as a chemical antioxidant. In the NO assay, the hexane fraction effectively scavenged free radicals at all dose ranges and is expected to inhibit NO production in mammalian cells. The hexane fraction effectively prevented oxidative damage, which was induced by Cu<SUP>2+</SUP>/H2O2, to target proteins at lower concentrations (@@>@@1 μg·mL<SUP>-1</SUP>). The DNA fragmentation and the cell-level assays suggest that the hexane fraction may play a crucial role in inhibiting peroxynitrite and H2O2 attack. Based on the findings described in this study, the hexane fraction holds promise for use as a novel pharmaceutical antioxidant. </P>

Ultrasonic Guided-Wave Mode Identification in Pipe by Using Air-Coupled Transducer and Time-Frequency Analysis

Park, Ik Keun,Kim, Hyun Mook,Kim, Yong Kwon,Cho, Yong Sang Trans Tech Publications, Ltd. 2006 Key Engineering Materials Vol.321 No.-

<P>For efficient NDE of pipes, essential components of power plant facilities, ultrasonic guided waves were generated and received applying an air-coupled transducer and comb one as non-contact technology. Mode generation and selection were predicted based on theoretical dispersive curve and the element space of a comb transducer. In addition, a receiving angle of the air-coupled transducer was determined to acquire the predicted modes by theoretical phase velocity of each mode. Theoretical dispersive curve was compared with the results of the time-frequency spectroscopes based on the wavelet transform and 2D-FFT to identify the characteristics of the received mode. The received modes show a good agreement with the predicted ones.</P>

Endovenous Laser Ablation of Varicose Veins after Direct Percutaneous Puncture: Early Results

PARK, SANG WOO,YUN, IK JIN,HWANG, JAE JOON,LEE, SONG AM,KIM, JUN SEOK,CHANG, SEONG-HWAN,CHEE, HYUN KEUN,HONG, SUK JOO Blackwell Publishing Inc 2007 Dermatologic surgery Vol.33 No.10

<P>BACKGROUND</P><P>Although endovenous laser ablation has been demonstrated to effectively occlude incompetent saphenous veins, it does not treat branch varicosities directly.</P><P>OBJECTIVE</P><P>The objective was to evaluate the technical feasibility and early results of the direct ablation of branch varicosities using a 980-nm diode laser.</P><P>MATERIALS AND METHODS</P><P>From July to August 2005, 17 patients (21 limbs; male:female ratio, 7:10; mean age, 50.1 years; range, 24–62 years) with varicose veins were enrolled in this study. Endovenous laser ablation was performed in incompetent saphenous veins. Thereafter, branch varicosities were percutaneously punctured and a direct laser ablation was performed using a 400-μm laser fiber. Patients were evaluated at 1 week and at 1-, 3-, and 6-month intervals.</P><P>RESULTS</P><P>Technical success in branch varicosities was achieved in 11 of 15 limbs (71.4%). Continued closure of treated saphenous veins was evident in 11 of 11 limbs (100%) at 1-month follow-up. Successful ablation in varicose tributaries was seen in 6 of 11 limbs (54.5%) at 1-month follow-up and ablation failed in 5 limbs. One of the 11 limbs (9%) had a skin burn that required treatment.</P><P>CONCLUSION</P><P>Despite partly successful occlusion, we suggest that direct laser ablation cannot replace classic methods of treating branch varicosities, because of its high failure rate and the risk of skin burns.</P>

Design of signed powers-of-two coefficient perfect reconstruction QMF Bank using CORDIC algorithms

Sang Yoon Park,Nam Ik Cho IEEE 2006 IEEE transactions on circuits and systems. a publi Vol.53 No.6

<P>Lattice structures have several advantages over the tapped delay line form, especially for the hardware implementation of general digital filters. It is also efficient for the implementation of quadrature mirror filter (QMF), because the perfect reconstruction is preserved under the coefficient quantization. Moreover, if lattice coefficients are implemented in signed powers-of-two (SPT), the hardware complexity can also be reduced. But the discrete coefficient space with the SPT representation is sparse when the number of nonzero bits is small. This paper proposes a structure of orthogonal QMF lattice with SPT coefficients, which has much denser discrete coefficient space than the conventional structure. While the conventional approaches directly quantize the lattice coefficients into SPT form, the proposed algorithm considers the quantization in the SPT angle space. For this, each lattice stage is implemented by the cascade of several variants of COordinate Rotation DIgital Computer. The resulting angle space and corresponding discrete coefficient space is much denser than the one generated by the conventional direct quantization approach. An efficient coefficient search algorithm for this structure is also proposed. Since the proposed architecture provides denser coefficient space, it shows less coefficient quantization error than the conventional QMF lattice</P>