• Fibers and Polymers
• /
• v.5 no.4
• /
• pp.253-258
• /
• 2004

Living nature of photoinduced cationic polymerization of isobutyl vinyl ether (IBVE) in the presence of various combinations of diphenyliodonium halide (DPIX), a photocationic initiator and zinc halide $(ZnX_2)$ in methylene chloride has been investigated. Attainment of $100\%$ conversion and a linear relationship between $\%$conversion and number average molar mass of the resulting polymer, strongly suggests the living nature of this system. Livingness of the polymerization system was observed irrespective to the type of halide anion of the initiator and zinc salts unless the reaction temperature is not higher than $-30^{\circ}C$. The rate of polymerization decreases in the order of iodide > bromide > chloride when halide salt of DPIX and $ZnX_2$ are used. It is postulated that the cationic initiation is started by the insertion of weakly basic monomer in to the activated C-X terminal of the monomer adduct which is a reaction product of monomer and HX, a photolytic product of DPIX, formed in situ during the photo-irradiation process. It was concluded that polymerization is initiated by the insertion of weakly basic monomer into activated C- X terminal of monomer adduct due to the pulling action of$ZnX_2$, which successively producing a new polarized C-X terminal for the propagation in cationic nature. This led us to a conclusion that the living nature of this cationic polymerization is ascribable to the polarized C-X growing terminal, which is stable enough to depress the processes of chain transfer or termination process.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.10B
• /
• pp.939-945
• /
• 2008

Tn this paper we described the process and the results of an implementation of Internet terminal using G.729.1 wideband speech codec for next generation network. For this purpose firstly we chose a high performance RISC application processor having DSP features for speech codec processing and enhanced Multimedia Accelerator(eMMA) function for video codec. In the implementation of this terminal, we used G.729.1 codec recently standardized in ITU-T which is a new scalable speech and audio codec that extends 0.729 speech coding standard. To adopt G.729.1 codec to this terminal we transformed most of the fixed point C codes which require more complexity into assembly codes so as to minimize processing time in the processor. As a result of this work we reduced the execution time of the original C codes about 80% and operated in real time on the terminal. For video we used H.263/MPEG-4 codec which is supported by the eMMA with hardware in the processor. In the SIP call processing test connected to real network we obtained under looms end-to-end delay and 3.8 MOS value measured with PESQ instrument. Besides this terminal operated well with commercial terminals.

• Journal of Navigation and Port Research
• /
• v.35 no.2
• /
• pp.167-172
• /
• 2011

The motivation of this study is the recent advancement of the Straddle Carrier (S/C). Previously Straddle Carrier (S/C) system was used focusing on container lift on/off due to its lower driving speed than that of (Y/T). Shuttle Carrier is evaluated as an upgraded Straddle Carrier. Recently, however, the driving speed of (S/C) has been improved to the level of Yard Tractor and Trailer systems (Y/T), which is 30Km per hour which makes (S/C) qualified as terminal in-yard transportation equipment. This paper, therefore, aims to evaluate three types of terminal in-yard transportation equipments such as (Y/T), (AGV) and the advanced (S/C) from economic perspective. The results revealed that by observing the total costs of equipment, (S/C) is a cheaper option than (Y/T) over 20 years, and than (AGV) over 6 years.

• Journal of Microbiology and Biotechnology
• /
• v.27 no.4
• /
• pp.775-784
• /
• 2017

A neutral xylanase (CcXyn) was identified from Coprinus cinereus. It has a single GH10 catalytic domain with a basic amino acid-rich extension (PVRRK) at the C-terminus. In this study, the wild-type (CcXyn) and C-terminus-truncated xylanase ($CcXyn-{\Delta}5C$) were heterologously expressed in Pichia pastoris and their characteristics were comparatively analyzed with aims to examine the effect of this extension on the enzyme function. The circular dichorism analysis indicated that both enzymes in general had a similar structure, but $CcXyn-{\Delta}5C$ contained less ${\alpha}-helices$ (42.9%) and more random coil contents (35.5%) than CcXyn (47.0% and 32.8%, respectively). Both enzymes had the same pH (7.0) and temperature ($45^{\circ}C$) optima, and similar substrate specificity on different xylans. They all hydrolyzed beechwood xylan primarily to xylobiose and xylotriose. The amounts of xylobiose and xylotriose accounted for 91.5% and 92.2% (w/w) of total xylooligosaccharides (XOS) generated from beechwood by CcXyn and $CcXyn-{\Delta}5C$, respectively. However, truncation of the C-terminal 5-amino-acids extension significantly improved the thermostability, SDS resistance, and pH stability at pH 6.0-9.0. Furthermore, $CcXyn-{\Delta}5C$ exhibited a much lower $K_m$ value than CcXyn (0.27 mg/ml vs 0.83 mg/ml), and therefore, the catalytic efficiency of $CcXyn-{\Delta}5C$ was 2.4-times higher than that of CcXyn. These properties make $CcXyn-{\Delta}5C$ a good model for the structure-function study of $({\alpha}/{\beta})_8$-barrel-folded enzymes and a promising candidate for various applications, especially in the detergent industry and XOS production.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.9
• /
• pp.2629-2634
• /
• 2013

Fisetin is a naturally occurring flavonoid with some anti-cancer and anti-inflammation capabilities. In this study, we perform docking studies between human c-Jun N-terminal kinase 1 (JNK 1) and fisetin and proposed a binding model of fisetin and JNK 1, in which the hydroxyl groups of the B ring and oxygen at the 4-position of the C ring play key roles in binding interactions with JNK. Fluorescence quenching and saturation-transfer difference (STD) NMR experiments showed that fisetin exhibits good binding affinity to JNK, $1.32{\times}10^8M^{-1}$. The anti-inflammatory activity of fisetin was also investigated. Fisetin significantly suppressed tumor necrosis factor, the NO production, and macrophage inflammatory cytokine release in LPS-stimulated RAW264.7 mouse macrophages. We found that the anti-inflammatory cascade of fisetin was mediated through the JNK, and cyclooxygenase (COX)-2 pathways. Our findings suggest the potential of fisetin as an anti-inflammatory agent.

• Journal of Microbiology and Biotechnology
• /
• v.20 no.12
• /
• pp.1756-1763
• /
• 2010

Pasteurella multocida serogroup D strain, which produces P. multocida toxin (PMT), is a widespread and harmful pathogen of respiratory diseases such as pneumonia and progressive atrophic rhinitis (PAR) in swine. Vaccination has been considered the most desirable and effective approach for controlling the diseases caused by toxigenic P. multocida. To investigate the antigenicity and immunogenicity of partial fragments of recombinant PMT, recombinant proteins of the N-terminal (PMT-A), middle (PMT-B), C-terminal (PMT-C), and middle-C-terminal (PMT2.3) regions of PMT were successfully produced in an Escherichia coli expression system. The molecular masses of PMT-A, PMT-B, PMT-C, and PMT2.3 were ca. 53, 55, 35, and 84 kDa, respectively, purified by nickel-nitrilotriacetic acid (Ni-NTA) affinity column chromatography. All the recombinant proteins except for PMT-A showed immune responses to antisera obtained from a swine showing symptoms of PAR. Moreover, high titers of PMT-specific antibodies were raised from mice immunized with each of the recombinant proteins; however, the immunoreactivities of the antibodies to authentic PMT and heat-inactivated whole bacteria were different, respectively. In the protection study, the highest protection against homologous challenge was shown in the case of PMT2.3; relatively poor protections occurred for the other PMT fragments.

• Animal cells and systems
• /
• v.5 no.2
• /
• pp.133-137
• /
• 2001

Long terminal repeats (LTRs) of the human endogenous retrovirus K family (HERV-K) have been found to be coexpressed with sequences of genes closely located nearby. We examined transcribed HERV-K LTR elements in human brain tissue. Using cDNA synthesized from mRNA of the human brain, we performed PCR amplification and identified ten HERV-K LTR elements. These LTR elements showed a high degree of sequence similarity (92.4-99.7%) with the human-specific LTR elements. A phylogenetic tree obtained by the neighbor-joining method revealed that HERV-K LTR elements could be divided into two groups through evolutionary divergence. Some HERV-K LTR elements (HKL-B7, HKL-B8, HKL-B10) belonging to the group II from human brain cDNA were closely related to the human-specific HERV-K LTR elements. Our data suggest that HERV-K LTR element are active in the human brain; they could conceivably play a pathogenic role in human diseases such as psychosis.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2012.10a
• /
• pp.723-724
• /
• 2012

• Proceedings of the KIEE Conference
• /
• 2001.07c
• /
• pp.1442-1444
• /
• 2001

A new low-temperature poly-Si TFT employing a counter-doped lateral body terminal is proposed and fabricated, in order to enhance the stability of poly-Si TFT driving circuits. The LBT structure effectively suppresses the kink effect by collecting the counter-polarity carriers and suppresses the hot carrier effect by reducing the peak lateral field at the drain junction. The proposed device is immune to dynamic stress, so that it is suitable for low voltage and high speed driving circuits of AMLCD.

• BMB Reports
• /
• v.47 no.4
• /
• pp.192-196
• /
• 2014

RNA polymerase II carboxyl-terminal domain (pol II CTD) phosphatases are a newly emerging family of phosphatases that are members of DXDX (T/V). The subfamily includes Small CTD phosphatases, like SCP1, SCP2, SCP3, TIMM50, HSPC129 and UBLCP. Extensive study of SCP1 has elicited the diversified roles of the small C terminal domain phosphatase. The SCP1 plays a vital role in various biological activities, like neuronal gene silencing and preferential Ser5 dephosphorylation, acts as a cardiac hypertrophy inducer with the help of its intronic miRNAs, and has shown a key role in cell cycle regulation. This short review offers an explanation of the mechanism of action of small CTD phosphatases, in different biological activities and metabolic processes.