• Korean Journal of Pharmacognosy
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• v.34 no.1 s.132
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• pp.18-24
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• 2003

The repeated column chromatographic separation of the MeOH extract of Laportea bulbifera Weddell resulted in the isolation of five flavonoids. Structures of the isolated compounds have been identified as $isorhamnetin-7-O-{\alpha}-L-rhamnoside$ (1), $isorhamnetin-3-O-{\alpha}-L-rhamnoside$ (2), $isorhamnetin-3,7-O-{\alpha}-L-dirhamnoside$ (3), $isorhamnetin-3-O-{\alpha}-L-rhamnopyranosyl-(1{\rightarrow}2)-{\beta}-galactopyranoside$ (4), $isorhamnetin-3-O-{\alpha}-rhamosyl-(1{\rightarrow}2)-rhamnoside$ (5) by spectroscopic means.

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.11a
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• pp.22-27
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• 1999

고급복합재료(advanced composite material)는 여러 가지 훌륭한 장점에도 불구하고 건설기술자에게는 그 이론이 너무 복잡하여 건설구조에 대한 응용이 지연되고 있다. [$\alpha/\beta/\beta/\gamma/\alpha/\alpha/\beta$]r, $\alpha$=-$\beta$, $\gamma$=0$^{\circ}$ 또는 90$^{\circ}$ 와 같은 몇 가지 배향각을 갖은 적층판은, r이 증가함에 따라, $B_{i,j}$강성이 0으로 접근한다(1995). 건설구조물은 그 치수가 커서 r이 증가해도 지간 대 두께비가 충분히 커서, 횡방향 변형율(${\varepsilon}_{xz}$,${\varepsilon}_{yz}$)의 영향이 무시될 수 있다. 이 경우 판의 지배방정식은 간단한 특별직교이방성판의 식으로 변화된다. 김덕현은 토목구조물에 흔히 적용될 수 있는 이러한 배향각을 가진 적층판의 지배방정식을 취급이 간단한 특별직교 이방성 판의 경우로 변경시킨 다음 해석을 더 간단히 진행할 수 있도록 기술자들이 유사 등방성 상수(quasi-isotropic constant)를 사용하여 낮익은 등방성판의 방정식을 사용하여 답을 구한 다음 그가 개발한 "수정계수(correction factor)"를 사용하여 "정확한"해를 구하는 방법을 발표한바 있다(1991).는 방법을 발표한바 있다(1991).

• BMB Reports
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• v.42 no.5
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• pp.260-264
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• 2009

Tumor necrosis factor-$\alpha$ (TNF-$\alpha$) exhibits cytotoxicity towards various tumor cells in vitro and induces apoptotic necrosis in transplanted tumors in vivo. It also shows severe toxicity when used systemically for the treatment of cancer patients, hampering the development of TNF-$\alpha$ as a potential anticancer drug. In order to understand the structure-function relation of TNF-$\alpha$ with respect to receptor binding, we selected four regions on the bottom of the TNF-$\alpha$ trimer that are in close contact with the receptor and carried out mutagenesis studies and computational modeling. From the study, various TNF-$\alpha$ muteins with a high therapeutic index were identified. These results will provide a structural basis for the design of highly potent TNF-$\alpha$ for therapeutic purposes. By conjugating TNF-$\alpha$ muteins with a high therapeutic index to a fusion partner, which targets a marker of angiogenesis, it could be possible to develop TNF-$\alpha$ based anticancer drugs.

• Microbiology and Biotechnology Letters
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• v.13 no.3
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• pp.223-232
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• 1985

To find microorganisms of producing $\alpha$-amylase inhibitors, actinomycetes were isolated from soil samples that were collected at different locations in Korea and screened for enzyme inhibitory activity. A strain of these microbes had a high inhibitory activity and was identified as one of the genus Streptomyces by morphological, biochemical and physiological studies according to the methods of the International Streptomyces Project (ISP). The medium used consisted of 3 ％ corn starch, 0.2％ yeast extract and 0.8％ peptone (pH 7.0). When this strain was aerobically cultured in the medium on a rotary shaker, the highest inhibitory activity was obtained after four days. This inhibitor had inhibitory activities on various $\alpha$-amylases and glucoamylase, but not on $\beta$-amylase.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.1
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• pp.107-110
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• 2001

In order to estimate the UV-A line's cut efficiency it lens, it was measured the light transmittance in the 320~400nm wavelength regions. We obtained the area to integrate the light transmittance of standard CR-39 and sample in the 320~400nm wavelength regions and established ${\alpha}$, ${\beta}$ of UV-A line's cut efficiency by contrast its area. We obtained the absolute cut efficiency ${\alpha}$ CR=0.59 value of CR-39 Lens, and if ${\alpha}$ was the absolute cut efficiency value of the lens to estimate UV-A cut effect, the relative cut efficiency ${\beta}$ was $1.69{\alpha}$. It was obtained the absolute and the relative UV exclusion index through each $a=(1-{\alpha}){\times}100%$, $b=(1-{\beta}){\times}100%$.

• Journal of Microbiology and Biotechnology
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• v.20 no.3
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• pp.563-568
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• 2010

The Val289 residue in the $\alpha$-amylase of Bacillus amyloliquefaciens, which is equivalent to the Ala289 and Val286 residues in the $\alpha$-amylases of B. stearothermophilus and B. licheniformis, respectively, was studied by site-directed mutagenesis. This residue was substituted with 10 different amino acids by random substitution of the Val codon. In these mutant $\alpha$-amylases, Val289 was substituted with Ile, Tyr, Phe, Leu, Gly, Pro, Ser, Arg, Glu, and Asp. Compared with the wild-type $\alpha$-amylase, the mutant $\alpha$-amylase Val289Ile showed 20% more hydrolytic activity, whereas Val289Phe and Val289Leu showed 50% lesser activity. On the other hand, the mutant $\alpha$-amylases Val289Gly, Val289Tyr, Val289Ser, and Val289Pro showed less than 15% activity. The substitution of Val289 with Arg, Asp, or Glu resulted in complete loss of the $\alpha$-amylase activity. Interestingly, the mutant $\alpha$-amylase Val289Tyr had acquired a transglycosylation activity, which resulted in the change of product profile of the reaction, giving a longer oligosaccharide.

• Korean Journal of Animal Reproduction
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• v.26 no.4
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• pp.395-399
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• 2002

Human chorionic gonadotropin (hCG) is a member of the glycoprotein hormone family which includes FSH. hCG TSH. These hormone family is characterized by a heterodimeric structure composed a common $\alpha$-subunit noncovalently linked to a hormone specific $\beta$-subunit. To determine u and $\beta$ -subunits can be synthesized as a single polypeptide chain (tethered-hCG) and also display biological activity, the tethered-hCC and -FSH molecule by fusing the carboxyl terminus of the hCG $\beta$-subunit to the amino terminus of the $\alpha$-subunit was constructed. To determine the importance of $\alpha$ COOH -terminal amino acid, we also deleted the $\alpha$ COOH-terminal amino acids. The expressing vectors were transfected into CHO-K 1 cells. The tethered-wthCG and -wtFSH was efficiently secreted. The $\alpha$ Δ83hCG and $\alpha$ Δ 83FSH mutants had no secretion. These results are the first conclusive evidence that COOH-terminal amino acids are very important for secretion in human glycoprotein hormone $\alpha$-subunit. These results demonstrated that the $\alpha$ Δ83hCG and $\alpha$ Δ 83FSH mutants could be play a pivotal role in the secretion of tethered-molecule.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.5
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• pp.331-336
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• 2010

In rapidly growing tumors, hypoxia commonly develops due to the imbalance between $O_2$ consumption and supply. Hypoxia Inducible Factor (HIF)-$1{\alpha}$ is a transcription factor responsible for tumor growth and angiogenesis in the hypoxic microenvironment; thus, its inhibition is regarded as a promising strategy for cancer therapy. Given that CamKII or PARP inhibitors are emerging anticancer agents, we investigated if they have the potential to be developed as new HIF-$1{\alpha}$-targeting drugs. When treating various cancer cells with the inhibitors, we found that a CamKII inhibitor, KN-62, effectively suppressed HIF-$1{\alpha}$ specifically in hepatoma cells. To examine the effect of KN-62 on HIF-$1{\alpha}$-driven gene expression, we analyzed the EPO-enhancer reporter activity and mRNA levels of HIF-$1{\alpha}$ downstream genes, such as EPO, LOX and CA9. Both the reporter activity and the mRNA expression were repressed by KN-62. We also found that KN-62 suppressed HIF-$1{\alpha}$ by impairing synthesis of HIF-$1{\alpha}$ protein. Based on these results, we propose that KN-62 is a candidate as a HIF-$1{\alpha}$-targeting anticancer agent.

• Journal of Biomedical Engineering Research
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• v.29 no.5
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• pp.355-363
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• 2008

In order to extract only the alpha activity related signals from EEG recordings, we have applied Constrained Independent Component Analysis (cICA), a new extension of ICA in which some a priori knowledge of the alpha activity is utilized to extract only desired components. Its extraction (or filtering) performance has been compared to that of the conventional band-pass filtering via the scalp alpha power maps and cortical source maps of the alpha activity. Our results demonstrate that the alpha power maps and cortical source maps from the cICA-extracted alpha signals reveal more focalized alpha generating regions of the brain than those from the band-pass filtered alpha EEG signals. Furthermore they match more closely the activated regions of the brain mapped using fMRI, validating our results. We believe that the cICA-based filtering approach of EEG signals is a more effective means of extracting a specific brain activity reflected in EEG signals that will result in more accurate source localization or imaging maps.

• Food Science and Biotechnology
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• v.16 no.6
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• pp.902-909
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• 2007

Granular maize starch was treated with Thermus scotoductus 4-${\alpha}$-glucanotransferase (${\alpha}$-GTase), and its physicochemical properties were determined. The gelatinization and pasting temperatures of ${\alpha}$-GTase-modified starch were decreased by higher enzyme concentrations. ${\alpha}$-GTase treatment lowered the peak, setback, and [mal viscosity of the starch. At a higher level of enzyme treatment, the melting peak of the amylose-lipid complex was undetectable on the DSC thermogram. Also, ${\alpha}$-GTase-modified starch showed a slower retrogradation rate. The enzyme treatment changed the dynamic rheological properties of the starch, leading to decreases in its elastic (G') and viscous (G") moduli. ${\alpha}$-GTase-modified starch showed more liquid-like characteristics, whereas normal maize starch was more elastic and solid-like. Gel permeation chromatography of modified starch showed that amylose was degraded, and a low molecular-weight fraction with $M_w$ of $1.1{\times}10^5$ was produced. Branch chain-length (BCL) distribution of modified starch showed increases in BCL (DP>20), which could result from the glucans degraded from amylose molecules transferred to the branch chains of amylopectin by inter-/intra-molecular transglycosylation of ${\alpha}$-GTase. These new physicochemical functionalities of the modified starch produced by ${\alpha}$-GTase treatment are applicable to starch-based products in various industries.