• Journal of Life Science
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• v.12 no.1
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• pp.87-95
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• 2002

It was observed that the hot water extract of the leaves of Capsicum annuum L., a Korean edible plant, had a potent anti-complementary activity. Crude polysaccharide fraction(CAL-0) was obtained by methanol reflux, ethanol precipitation, dialysis and lyophilization. CAL-0 contained 51.8% of total sugar, 8.2% of uronic acid and 16.8% of protein, and consisted of mainly arabinose, galactose and glucose as neutral sugars and galacturonic acid as uronic acid. The anti-complementary activity of CAL-0 decreased greatly by periodate oxidation, but was not changed by pronase treatment. Also, the anti-complementary activity of CAL-0 was reduced partially in the absence of the $Ca^{2+}$ ion. The crude polysaccharide CAL-0 was found to activate the C3 component both in the presence and in the absence of $Ca^{2+}$ through the crossed-immunoelectrophoresis suggesting that those involved in both classical and alternative complement pathway CAL-0 was further separated to an unabsorbed fraction(CAL-1) and six absorbed fractions(CAL-2longrightarrowCAL-7) on DEAE Sepharose CL-6B ion exchange column. Among them four major fractions in activity and yield were obtained, and consisted mainly of arabinose, galactose and glucose with various molar ratios. The major fraction, CAL-2, was purified to give a high molecular fraction(CAL-2-I) and a low molecular fraction(CAL-2-II) on Sepharose CL-6B column. The anti-complementary activity of CAL-2-I, a molecular weight of about 61,000, was higher than it of CAL-2-II.-II.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.4 s.95
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• pp.397-401
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• 2005

In this paper, a slot-coupled microstrip antenna with switchable polarization is proposed for the polarization diversity applications in the complicated communication environment. The proposed antenna is fed by a microstrip line through one of two slots located with the interval of $\lambda{g}/4$ in the ground plane. By switching the PIN diode between opened and shorted termination which is located at the tip of the microstrip line, the switching function between horizontal and vertical polarization was confirmed experimentally. The measured resonant frequencies of the fabricated antenna are $2.41\;\cal{GHz}\;2.40\;\cal{GHz}$ and the cross polarization levels are $19\;\cal{dB},\;23\;\cal{dB},\;the\;-10\;\cal{dB}$ return loss bandwidths are $95\;\cal{MHz}\;100\;\cal{MHz}$ in horizontal and vertical polarization, respectively, and the antenna gain is almost $6\;\cal{dBi}$.

• Kyungpook Mathematical Journal
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• v.45 no.2
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• pp.199-209
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• 2005

An ideal space is ${\cal{I}}-resolvable$ if it has two disjoint ${\cal{I}}-dense$ subsets. We answer the question: If X is ${\cal{I}}-resolvable$, then is X (${\cal{I}}\;{\cup}\;{\cal{N}$)-resolvable?, posed by Dontchev, Ganster and Rose. We give three generalizations of the well known Banach Category Theorem and deduce the Banach category Theorem as a corollary. Characterizations of completely codense ideals and ${\cal{I}-locally$ closed sets are given and their properties are discussed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.4 s.95
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• pp.345-350
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• 2005

An X-band push-push VCO for low cost applications is proposed. The designed push-push oscillator achieves a wide tuning range in the X-band by the collector bias tuning instead of extra varactor diodes. The measurement shows a wide tuning bandwidth of $900\;\cal{MHz}\;from\;10.9\;\cal{GHz}\;to\;11.8\;\cal{GHz}$ with a drain bias voltage varying from 4 to 9 V, excellent fudamental suppression of $-30\;\cal{dBc}$ and good phase noise of $-115\;\cal{dBc/Hz}\;@\;1\;\cal{MHz}$ offset.

• Economic and Environmental Geology
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• v.38 no.2 s.171
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• pp.135-142
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• 2005

In order to investigate the contamination level and seasonal variation of heavy metals and evaluate the bioavailability of toxic elements, environmental geochemical survey was undertaken at the Dogok Au-Ag-Cu mine area. The main pollution sources in the area were suggested as tailings, mine waste materials and mine water. Elevated levels of $140{\cal}mg/{\cal}kg{\;}As,{\;}107{\cal}mg/{\cal}kg{\;}Cd,{\;} 3017{\cal}mg/{\cal}kg{\;}Cu,{\;}12926{\cal}mg/{\cal}kg{\;}Pb,{\;}9094{\cal}mg/{\cal}kg$ Zn(before rainy season) were found in mine tailings. Concentrations of heavy metals in farmland soils exceeded normal level in nature soil (Bowen, 1979). The highest level of heavy metals was found in water samples near the mine tailing dumps regarded as a main pollution source of toxic elements in the area. These concentrations decreased to downstream due to the effect of dilution. From the results of sequential extraction analyses for tailings and soils, non-residual forms of heavy metals were found, which indicate the contamination to be progressing by continuing weathering and oxidation. Cadmium and Zn would be of the highest mobility in all samples. The bioavailability of Cd, Cu, Zn and As using SBET analysis from paddy soils was $53.3{\%},{\;}46.5{\%},{\;}41.0{\%}$ and $37.0\%$, respectively. The farmland soil sample(S3) showed the highest total concentration and bioavailability of heavy metals.

• Kyungpook Mathematical Journal
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• v.50 no.4
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• pp.537-543
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• 2010

Let X be a regular $T_1$-space such that each single point set is a $G_{\delta}$ set. Denot 'hereditarily closure-preserving' by 'HCP'. To consider a question of closed maps of S. Lin in [6], we improve some results of Foged in [1], and prove the following propositions. Proposition 1. $D\;=\;\{x{\in}X\;:\;\mid\{F{\in}\cal{F}:x{\in}F\}\mid{\geq}{\aleph}_0\}$ is discrete and closed if $\cal{F}$ is a collection of HCP. Proposition 2. $\cal{H}\;=\;\{{\cup}\cal{F}'\;:\;F'$ is an fininte subcolletion of $\cal{F}_n\}$ is HCP if $\cal{F}$ is a collection of HCP. Proposition 3. Let (X,$\tau$) have a $\sigma$-HCP k-network. Then (X,$\tau$) has a $\sigma$-HCP k-network F = ${\cup}_n\cal{F}_n$ such that such tat: (i) $\cal{F}_n\;\subset\;\cal{F}_{n+1}$, (ii) $D_n\;=\;\{x{\in}X\;:\;\mid\{F{\in}\cal{F}_n\;:\;x{\in}F\}\mid\;{\geq}\;{\aleph}_0\}$ is a discrete closed set and (iii) each $\cal{F}_n$ is closed to finite intersections.

• Journal of Microbiology and Biotechnology
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• v.17 no.8
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• pp.1308-1315
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• 2007

Lipase B from Candida antarctica (CalB) displayed on the cell surface of H. polymorpha has been functionally improved for catalytic activity by molecular evolution. CalB was displayed on the cell surface by fusing to a cell-wall anchor motif (CwpF). A library of CalB mutants was constructed by in vivo recombination in H. polymorpha. Several mutants with increased whole-cell CalB activity were acquired from screening seven thousand transformants. The two independent mutants CalB 10 and CalB 14 showed an approximately 5 times greater whole-cell activity than the wild-type. When these mutants were made as a soluble form, CalB 10 showed 6 times greater activity and CalB 14 showed an 11 times greater activity compared with the wild-type. Sequence analyses of mutant CALB genes revealed amino acid substitutions of $Leu^{278}Pro$ in CalB10 and $Leu^{278}Pro/Leu^{219}Gln$ in CalB14. The substituted $Pro^{278}$ in both mutants was located near the proline site of the ${\alpha}$10 helix. This mutation was assumed to induce a conformational change in the ${\alpha}$10 helix and increased the $k_{cat}$ value of mutant CalB approximately 6 times. Site-directed mutagenized CalB, LQ ($Leu^{219}Gln$) was secreted into the culture supernatant at an amount of approximately 3 times more without an increase in the CalB transcript level, compared with the wild-type.

• KSBB Journal
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• v.23 no.5
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• pp.403-407
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• 2008

Recently, Candida antarctica lipase B (CalB) draws attention from industries for various applications for food, detergent, fine chemical, and biodiesel, because of its characteristics as an efficient biocatalyst. Since many industrial processes carry out in organic solvent and at high temperature, CalB, which is stable under harsh condition, is in demand from many industries. In order to reform CalB promptly, the expression system which has advantages of ease to use and low cost for gene libraries screening was developed using E. coli. The E. coli strains, Rosettagami with competence for enhanced disulfide bond formation, Novablue, and $DH5{\alpha}$, were exploited in this study. To obtain the soluble CalB, the pCold I vector expressing the cloned gene at $15^{\circ}C$ and the chaperone plasmids containing groES/groEL, groES/groEL/tig, tig, dnaK/dnaJ/grpE, and dnaK/dnaJ/grpE/groES/groEL were used for coexpression of CalB and chaperones. The colonies expressing functional lipase were selected by employing the halo plate containing 1% tributyrin, and the CalB expression was confirmed by SDS-PAGE. E. coli Rosettagami and $DH5{\alpha}$ harbouring groES/groEL chaperones were able to express soluble CalB effectively. From a facilitative point of view, E. coli $DH5{\alpha}$ is more suitable for further mutation study.

• The Korean Journal of Ecology
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• v.28 no.1
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• pp.37-43
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• 2005

This study presents the Mid-Lateglacial vegetation history of southwestern Korea. From the result of AMS dating and pollen analysis, four local pollen assemblage zones(BS) were recognized. The four local pollen assemblage zones are BS 1. 12,222cal BC$\sim$9,160cal BC: cool-temperate northern/altimontane mixed coniferous & deciduous broad-leaved forest, BS 2. 9,160cal BC$\sim$ 4,210cal BC: cool-temperate central/montane deciduous broad-leaved forest, BS 3. 4,210cal BC$\sim$125cal BC: cool-Temperate southern/submontane mixed coniferous & deciduous broad-leaved forest. BS 4. BC125cal ${\sim}$present: warm-temperate/cool-temperate southern/submontane coniferous forest. Pine forest expanded since 4,210cal BC and full-scale rice cultivation might started since 2,120cal BC. A radical expansion of Pinus densiflora forest after postglacial stage might be caused by human impacts including full-scale agriculture.

• Communications of the Korean Mathematical Society
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• v.25 no.4
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• pp.497-510
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• 2010

Let R be a ring and n a fixed non-negative integer. $\cal{TI}_n$ (resp. $\cal{TF}_n$) denotes the class of all right R-modules of FGT-injective dimensions at most n (resp. all left R-modules of FGT-flat dimensions at most n). We prove that, if R is a right $\prod$-coherent ring, then every right R-module has a $\cal{TI}_n$-cover and every left R-module has a $\cal{TF}_n$-preenvelope. A right R-module M is called n-TI-injective in case $Ext^1$(N,M) = 0 for any $N\;{\in}\;\cal{TI}_n$. A left R-module F is said to be n-TI-flat if $Tor_1$(N, F) = 0 for any $N\;{\in}\;\cal{TI}_n$. Some properties of n-TI-injective and n-TI-flat modules and their relations with $\cal{TI}_n$-(pre)covers and $\cal{TF}_n$-preenvelopes are also studied.