• Journal of the Korean Ceramic Society
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• v.11 no.3
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• pp.19-26
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• 1974

Mechanical properties of the system PbO-B2O3-V2O5 low melting glass during crystallization by heat-treatment were investigated. Wettability of the system PbO-B2O3-V2O5 was excellent and appropriate for commercial sealing as a low melting solder glass. Crystals, during heat-treated at 30$0^{\circ}C$ of the system PbO-B2O3-V2O5 were $\beta$-4PbO.B2O3, 5PbO.4B2O3, and Pb2V2O7 mainly. The percent of crystallinity was 82$\pm$5%. Mechanical properties of the system PbO-B2O3-V2O5 were influenced not only by the differences of density and coefficient of thermal expansion and the stress induced from the difference in the density and coefficient of thermal expansion between glass phase and crystals but also crystallization conditions.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.10
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• pp.103-109
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• 2003

We have proposed the 4-Dimensional Multiple-Subcarrier Modulation with fixed bias in Optical Wireless Communications. Here, the 4-D signal vectors are derived from the optimization technique of signal waveforms maximizing the minimum distance between signal points in an n-dimensional Euclidean sphere. The resulting vectors are used in generating the output amplitude of impulse generator in a Multiple-Subcarrier Modulation scheme. We have achieved that the normalized power requirement of the proposed system is maximum 3 dB and 3.3 dB smaller than those of normal QPSK, Reserved Subcarrier, and Minimum Power scheme, respectively. Also, in the range of 1.125 ∼ 1.25 of the normalized bandwidth, the proposed system has maximum 3 dB, 2 ∼ 4 dB, 0 ∼ 3 dB smaller bandwidth requirement compare to normal QPSK, Res. Subcarrier, Min. Power schemes, respectively.

• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1199-1203
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• 2003

Polyphenols were isolated from Korean green tea using Sephadex LH-20 and HPLC. The isolated polyphenols were procyanidin B-4, procyanidin B-2-3,3'-digallate, prodelphinidin C-2-3,3'-di-O-digallate, (+)-catechin-3-O-rhamnose, procyandin B-5, procyanidin B-7-3-0-gallate, gallate, epiafzelechin-$(4{\beta}{\rightarrow}8)$-epiafzelechin, procyanidin B-3-3-O-rhamnose, afzelechin-$(4{\alpha}{\rightarrow}8)$-catechin, prodelphinidin B-5-3,3'-di-O-digallate and (+)-taxifolin-3-O-D-xyloside. The inhibitory effects of prodelphinidin C-2-3,3'-di-O-gallate and procyanidin B-2-3,3'-digallate $(at\;100{\mu}M)$ on angiotensin.converting enzyme were 68.8 and 54.6%, respectively, while the inhibitory effects of prodelphinidin C-2-3,3'-di-O-gallated and procyanidin B-2-3,3'-digallate $(at\;100{\mu}m)$ on xanthine oxidase were 54.5 and 38.2%, respectively. Lastly, the inhibitory activities of prodelphinidin C-2-3,3'-di-O-gallate $(at\;100{\mu}m)$ on tyrosinase was 42.1%.

• Membrane Journal
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• v.25 no.2
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• pp.115-122
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• 2015

$SiO_2{\cdot}B_2O_3$ was prepared by trimethylborate (TMB)/tetraethylorthosilicate (TEOS) mole ratio 0.01 at $800^{\circ}C$. PDMS[poly(dimethysiloxane)]-$SiO_2{\cdot}B_2O_3$ composite membranes were prepared by adding porous $SiO_2{\cdot}B_2O_3$ to PDMS. To investigate the characteristics of PDMS-$SiO_2{\cdot}B_2O_3$ composite membrane, we observed PDMS-$SiO_2{\cdot}B_2O_3$ composite membrane using TG-DTA, FT-IR, BET, X-ray, and SEM. PDMS-$SiO_2{\cdot}B_2O_3$ composite membrane was studied on the permeabilities of $H_2$ and $N_2$ and the selectivity ($H_2/N_2$). Following the results of TG-DTA, BET, X-ray, FT-IR, $SiO_2{\cdot}B_2O_3$ was the amorphous porous $SiO_2{\cdot}B_2O_3$ with $247.6868m^2/g$ surface area and $37.7821{\AA}$ the mean of pore diameter. According to the TGA measurements, the thermal stability of PDMS-$SiO_2{\cdot}B_2O_3$ composite membrane was enhanced by inserting $SiO_2{\cdot}B_2O_3$. SEM observation showed that the size of dispersed $SiO_2{\cdot}B_2O_3$ in the PDMS-$SiO_2{\cdot}B_2O_3$ composite membrane was about $1{\mu}m$. The increasing of $SiO_2{\cdot}B_2O_3$ content in PDMS leaded the following results in the gas permeation experiment: the permeability of both $H_2$ and $N_2$ was increased, and the permeability of $H_2$ was higher than $N_2$, but the selectivity($H_2/N_2$) was decreased.

• Bulletin of the Korean Chemical Society
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• v.35 no.10
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• pp.2990-2994
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• 2014

The studies on design and synthesis of new monocyclic ${\beta}$-lactam esters 4(R/S)-(1'-methoxycarbonylpropyl- 2'(R/S)-thio)-3(R)-phenylacetamidoazetidin-2-one (3a) and 4(R/S)-(1'-methoxycarbonyl-2'-methylpropyl-2'- thio)-3(R)-phenylacetamidoazetidin-2-one (3b) were described. Compounds 3a and 3b were specifically designed to retain all penicillin substructures except the bicyclic system, which would be conceived by cleaving the C(3)-N(4) bond of penicillin G. Compounds 3a and 3b are of particular interest in the context of the structural elucidation of monocyclic ${\beta}$-lactams originated from penicillin. Key intermediates, ${\beta}$-mercapto esters 6a and 6b, were synthesized from conjugate acids 4a and 4b using three-step synthetic sequences, respectively, and 4(S)-acetoxy-3(S)-phenylacetamidoazetidin-2-one (7) was obtained from the degradation of penicillin G. Reactions of 6a and 6b with 7, thus obtained, provided the target compounds 3a and 3b, respectively.

• Journal of Applied Biological Chemistry
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• v.43 no.4
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• pp.273-276
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• 2000

In the course of surveying the anti-plaque agents for dental caries prevention, the extract of Korean green tea leaves (KGTL) was tested for inhibitory activity against Streptococcus mutans adhering to glass surfaces in the presence of crude glucosyltransferase (GTase). The extracts of KGTL showed a positive inhibitory activity against GTase. The active compound was purified through Sephadex LH-20 and MCI gel CHP-20P columns. A positive reaction was shown in the anisaldehyde-$H_2SO_4$ test, which confirmed the condensed tannin. The inhibitory compound was identified as 3-galloylprocyanidin $B_3$ through IR, negative FAB-mass, and $^{1}H$-NMR spectroscopic analyses. Acetone extract and 3- galloylprocyanidin $B_3$ of KGTL showed inhibitory effect against GTase. The percent of inhibition was determinated to be 71.84% (P<0.01) with 10 mM 3-galloylprocyanidin B3. The 3-galloylprocyanidin $B_3$, which possessed a galloyl, showed a higher inhibitory activity against glucosyltransferase than monomeric (+)-catechin and procyanidine $B_3$ which had no galloyl group.

• BMB Reports
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• v.39 no.4
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• pp.361-370
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• 2006

Genetic variation and molecular phylogeny of 22 taxa representing 14 extant species and 3 unidentified taxa of Boesenbergia in Thailand and four outgroup species (Cornukaempferia aurantiflora, Hedychium biflorum, Kaempferia parviflora, and Scaphochlamys rubescens) were examined by sequencing of 3 chloroplast (cp) DNA regions (matK, psbA-trnH and petA-psbJ). Low interspecific genetic divergence (0.25-1.74%) were observed in these investigated taxa. The 50% majority-rule consensus tree constructed from combined chloroplast DNA sequences allocated Boesenbergia in this study into 3 different groups. Using psbA-1F/psbA-3R primers, an insertion of 491 bp was observed in B. petiolata. Restriction analysis of the amplicon (380-410 bp) from the remaining species with Rsa I further differentiated Boesenbergia to 2 groupings; I (B. basispicata, B. longiflora, B. longipes, B. plicata, B. pulcherrima, B. tenuispicata, B. thorelii, B. xiphostachya, Boesenbergia sp.1 and Boesenbergia sp.3; phylogenetic clade A) that possesses a Rsa I restriction site and II (B. curtisii, B. regalis, B. rotunda and Boesenbergia sp.2; phylogenetic clade B and B. siamensis; phylogenetic clade C) that lacks a restriction site of Rsa I. Single nucleotide polymorphism (SNP) and indels found can be unambiguously applied to authenticate specie-origin of all investigated samples and revealed that Boesenbergia sp.1, Boesenbergia sp.2 and B. pulcherrima (Mahidol University, Kanchanaburi), B. cf. pulcherrima1 (Prachuap Khiri Khan) and B. cf. pulcherrima2 (Thong Pha Phum, Kanchanaburi) are B. plicata, B. rotunda and B. pulcherrima, respectively. In addition, molecular data also suggested that Boesenbergia sp.3 should be further differentiated from B. longiflora and regarded as a newly unidentified Boesenbergia species.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.3
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• pp.428-436
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• 2003

Epidemiological studies have observed a negative association between increased consumption of green and yellow vegetables and cancer incidence. These vegetables contain carotenoids, which are reported to exhibit anticarcinogenic effects. Overexpression of ErbB2 and ErbB3 genes is a frequent event in several human cancers. The present study was performed to determine whether $\alpha$-carotene, $\beta$-carotene, lutein, or lycopene inhibits cell growth and to assess such an effect is related to changes in the levels of the ErbB receptor family and tile ErbB3 receptor signaling pathway in HT-29 cells. HT-29 cells were cultured in serum-free medium in the presence of various concentrations (0~100 $\mu$M) of the individual carotenoids. $\alpha$ -Carotene and lycopene significantly inhibited cell growth in a dose-dependent manner, whereas lutein slightly inhibited cell growth and $\beta$-carotene increased cell growth. Lycopene is more potent than $\alpha$ -carotene in inhibiting HT-29 cell growth. Lycopene inhibited DNA synthesis and induced apoptosis of HT-29 cells. The ErbB3 ligand heregulin (HRG) increased cell growth but did not prevent the lycopene-induced inhibition of cell growth. Lycopene decreased ErbB2 protein levels in a dose-dependent manner. Immunoprecipitation/Western blot studies revealed that lycopene inhibited HRG-induced phosphorylation of ErbB3, recruitment of the 985 regulatory subunit of phosphatidylinositol 3-kinase (PI3K) to the ErbB3 receptor, and phosphorylation of Akt. These results indicate that downregulation of ErbB2/ErbB3/PI3K/Akt signaling may be one of the mechanisms by which lycopene inhibits HT-29 cell pro-liferation and induces apoptosis.

• Food Science and Preservation
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• v.20 no.3
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• pp.379-385
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• 2013

To establish the optimal manufacturing conditions of soybean koji, soybean Koji prepared with Aspergillus oryzae 6-M-1 and Bacillus subtilis 3-B-1 isolated from traditional Korean meju. During 7 days of making Koji, the amount of amino-type nitrogen was getting more increase. The amount of amino-type nitrogen of Koji prepared with A. oryzae 6-M-1 was 686.16 mg% (w/w), that of Koji with B. subtilis 3-B-1 was 643.46 mg% (w/w) at seventh day of making Koji. The ${\alpha}$-amylase activity of Koji prepared with A. oryzae 6-M-1 was 1472.54 unit/g, that of Koji with B. subtilis 3-B-1 was 791.00 units/g on the seventh day of the making. The acidic protease activity of Koji prepared with A. oryzae 6-M-1 was 309.00 unit/g, that of Koji with B. subtilis 3-B-1 was 135.88 unit/g at 7th day of making. The amount of amino-type nitrogen and enzyme activities of soybean Koji prepared with A. oryzae 6-M-1 and B. subtilis 3-B-1 were produced more than those of wheat flour Koji made in factory. Sensory evaluation on a commercial doenjang and doenjangs prepared with A. oryzae 6-M-1 and B. subtilis 3-B-1 was not significantly different at p<0.05.

• Korean Journal of Plant Taxonomy
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• v.38 no.4
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• pp.509-522
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• 2008

한국산 가막사리속(Bidens L.)에 포함된 10분류군(8종 2변종)의 수과형태를 연구하기 위하여 입체현미경과 주사전자현미경을 이용하여 관찰하였다. 연구된 가막사리속에서 까끄라기를 제외한 수과의 크기는 $3.0-19.5{\times}0.7-2.6 mm$이다. 관모는2-4개의 까끄라기로 구성되어 있고, 까끄라기의 길이는 2.2-5.6 mm이다. 강모의 배열은 1-3열이었다. 수과의 다형화가 6개의 분류군(B. bipinnata, B. biternata, B. frondosa, B. parviflora, B. pilosa var. pilosa, B. tripartita var. tripartita)에서 확인되었다. 수과의 형태와 까끄라기의 수에 의해 4가지 유형으로 구분되었다. - Type A: 장타원형이고, 까끄라기 수는 2개(B. parviflora); Type B: 장타원형이고, 까끄라기 수는 3개 이상(B. bipinnata, B. biternata, B. pilosa var. pilosa, B. pilosa var. minor) Type C: 도란형이고, 까끄라기의 수는 2개(B. frondosa, B. radiata var. radiata, B. radiata var. pinnatifida, B. tripartita var. tripartita); Type D: 도란형이고, 까끄라기의 수는 3개 이상(B. cernua). 까끄라기의 강모 표면무늬는 3가지 즉 나선상, 평활상, 불규칙한 직선형으로 나타났다. 수과의 표면은 각피층이 발달한 다각형, 평활상 그리고 굴곡형으로 나타났다. 수과형질의 분류학적 적용에 대하여 간략하게 토의하였다. 수과형질을 바탕으로 한국산 가막사리속 분류군에 대한 검색표를 제시하였다.