• Journal of Biosystems Engineering
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• 제8권2호
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• pp.26-38
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• 1983

Binder harvesters introduced to Korea were originally designed to be used for Japonica varieties which are highly resistant to shattering. In order to improve the performance of the binder to Indica varieties which are easily shattered and have shorter stem, mechanical modifications of the binder are inevitable. Shattering losses of the binder can be classified into two major parts; one incurred before and one after binding operations. The latter has been evaluated as great as the former. Previous studies indicated that the high discharge losses resulted from a great impact force of the discharge arm on the rice bundle during the discharge process. This study was intended to theoretically analyze the discharge mechanism of four-bar linkage. For this purpose, two commercially available binder harvesters having a four-bar linkage as a discharge mechanism were analyzed. Using the results from the motion analysis and the other structural constraints of the machines, they were modified and experimentally compared with the machines without modification to see whether any decrease in grain losses was obtained. The results obtained in this study are summarized as follows: 1. The path, velocity and acceleration of discharge arm were computer analyzed by vector analysis. Using results of the analysis and intrinsic constraints of the binder, discharge mechanism was modified to reduce the impact force on bundle by discharge arm in the range where the discharge performance was not deteriorated. This modification of the discharge mechanism could be done with an aid of four-bar linkage synthesis technique. As a result, average velocity and acceleration of the discharge arm during the discharge process were reduced respectively by 19 percent and 33 percent for binder A, and 17 percent and 35 percent for binder B. 2. Through the modification of the discharge mechanism, discharge losses of binder A were reduced by 42-56 percent for Milyang 23, Poongsan and Hangang chal, and discharge losses of binder B were reduced by 13-20 percent for Milyang 23 and Poongsan. 3. Discharge losses were decreased as the bundle size became larger and the size effect on the decrease rate appeared more significant in the binders with modifications than in those without modifications.

• Journal of Microbiology and Biotechnology
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• 제11권6호
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• pp.1115-1119
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• 2001

Eight Escherichia coli cells with aerobic growth deflects were isolated by the insertion of ${\lambda}placMu53$, a hybrid bacteriophage of ${\lambda}$ and Mu, which created transcriptional fusion to lacZY. Two of these mutants, CLIO and CLl2, were irradiated with UV to obtain specialized transducing phages. The phages that took out the neighboring chromosomal DNA of the related gene responsible for deflective aerobic growth were identified. The in vivo cloned chromosomal sequence revealed that the mutated gene of CLIO was located at min 34.5 on the Escherichia coli linkage map and 1,599,515 on the physical map. The physical map indicated that there were 7 cistrons in the operon. We named this operon oxg10. The promoter sequence of oxg10 exhibited a possible binding site far SoxS, a transcriptional regulator that activates the transcription of various SoxRS regulon genes. Transferring the oxg10:: ${\lambda}placMu53$ mutation into the wild-type strain, RZ4500, resulted in the inhibition of normal aerobic growth, while the salute mutation in strain MO inhibited aerobic cell growth completely. The full operon sequences of oxg10 were cloned from the Excherichia coli genomic library. The mutated gene of CLl2 was identified to be a sucA gene encoding the ${\alpha}$-ketoglutarate dehydrogenase El component in the TCA cycle.

• Journal of Photoscience
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• 제9권2호
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• pp.33-36
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• 2002

In vertebrate rhodopsins the glutamic acid at position 113 serves as a counterion to stabilize the protonated retinylidene Schiff base linkage and to shift the spectrum to the visible region. Invertebrate rhodopsins and retinochrome have the amino acid residue different from glutamic acid or asparatic acid at this position and therefore, these pigments may have a counterion at different position. We first investigated the counterion in retinochrome by site specific mutagenesis. The results showed that the counterion is the glutamic acid at position 181, where almost of all the pigments including vertebrate and invertebrate rhodopsins in the rhodopsin family have a glutamic acid or an aspartic acid. In vertebrate rhodopsins, however, Glu 181 does not act as a counterion, and the red-sensitive cone pigments have a histidine at this position, which serves as a chloride-binding site for red-shift of the absorption spectrum. These findings suggested that the role of Glu181 as a counterion may be weakened by the newly acquired counterion at position 113. Taken together with our recent studies on an invertebrate-type rhodopsin, the rhodopsin diversity was discussed from viewpoint of counterion.

• 한국자기공명학회논문지
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• 제2권2호
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• pp.131-140
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• 1998

The calcium-induced structural changes in the skeletal muscle regulatory protein troponin C (NTnC) involve a transition from a ‘closed’to an ‘open’structure with the concomitant exposure of a large hydrophobic interaction site for target proteins. Structural studies have served to define this conformational change and elucidate the mechanism of the linkage between calcium binding and the induced structural changes. There are now several structures of NTnC available from both NMR and X-ray crystallography. Comparison of the calcium bound structures reveals differences in the level of opening. We have considered the concept of a flexible open state of NTnC as a possible explanation for this apparent discrepancy. We also present simulations of the closed-to-open transition which are in agreement with the flexibility concept and with experimental energetics data.

• Bulletin of the Korean Chemical Society
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• 제6권5호
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• pp.300-303
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• 1985

To understand the nature of the linkage between chromophore and apoprotein in the photoreceptor of Stentor coeruleus, a conformational analysis has been carried out on the dipeptide amides linked to the chromophore hypericin using an empirical potential function. The conformational energies for the dipeptide amides of Glu (OHyp)-X-NHMe, where X = Leu, Phe, Asp, and Tyr, have been calculated to investigate the influence of peptide residues in stabilizing conformers. It was found that the increase of acidity of hypericin upon photoexcitation may be facilitated by the formation of intramolecular hydrogen bonds between hydroxyl groups of hypericin and carbonyl groups of peptide backbone, and that the stabilities of dipeptide amides do not significantly depend on peptide residues directly linked to chromophore.

• Korean Chemical Engineering Research
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• 제44권3호
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• pp.254-258
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• 2006

휘발성 유기화합물을 제거하는 허니콤 흡착제의 제조 성분인 무기질 섬유에 흡착력이 뛰어난 제올라이트를 화학 결합시켰다. 무기질 섬유를 염산, 황산 또는 플루오르화 수소산 등으로 처리하여 표면의 불순물을 제거하여 제올라이트의 접합 능력을 향상시켰다. 무기질 섬유와 제올라이트의 표면에 매달은 클로로프로필, 아미노프로필 또는 에폭시기 등을 서로 반응시켜 두 물질을 화학 결합시켰으며, 연결 화합물로 고분자 폴리에틸렌이민을 사용하기도 하였다. 결합상태는 전자현미경으로 관찰하였고, BET 표면적 분석을 통하여 제올라이트 접합량을 유추하였다. 폴리에틸렌이민을 사용하면 제올라이트를 무기질 섬유에 많이 결합시킬 수 있었다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권2호
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• pp.112-117
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• 2004

The performance of an immuno-analytical system can be assessed in terms of its analytical sensitivity, i.e., the detection limit of an analyte, which is determined by the amount of analyte molecules bound to the capture antibody that has been immobilized onto a solid surface. To increase the number of the binding complexes, we have investigated a site-directed immobilization of an antibody that has the ability to resolve a current problem associated with a random arrangement of the insolubilized immunoglobulin. The binding molecules were chemically reduced to produce thiol groups that were limited at the hinge region, and then, the reduced products were coupled to biotin. This biotinylated antibody was bound to a streptavidin-coated surface via the streptavidin-biotin reaction. This method can control the orientation of the antibody molecules present on a solid surface and also can significantly reduce the possibility of steric hindrance in the antigen-antibody reactions. In a two-site immunoassay, the introduction of the site-directly immobilized antibody as the capture enhanced the sensitivity of analyte detection approximately 10 times compared to that of the antibody randomly coupled to biotin. Such a novel approach would offer a protocol of antibody immobilization in order for the possibility of constructing a high performance immunochip.

• Molecules and Cells
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• 제20권1호
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• pp.1-16
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• 2005

The peptidyl transferase center (PTC) is located in a protein free environment, thus confirming that the ribosome is a ribozyme. This arched void has dimensions suitable for accommodating the 3'ends of the A-and the P-site tRNAs, and is situated within a universal sizable symmetry-related region that connects all ribosomal functional centers involved in amino-acid polymerization. The linkage between the elaborate PTC architecture and the A-site tRNA position revealed that the A-to P-site passage of the tRNA 3'end is performed by a rotatory motion, which leads to stereochemistry suitable for peptide bond formation and for substrate mediated catalysis, thus suggesting that the PTC evolved by genefusion. Adjacent to the PTC is the entrance of the protein exit tunnel, shown to play active roles in sequence-specific gating of nascent chains and in responding to cellular signals. This tunnel also provides a site that may be exploited for local co-translational folding and seems to assist in nascent chain trafficking into the hydrophobic space formed by the first bacterial chaperone, the trigger factor. Many antibiotics target ribosomes. Although the ribosome is highly conserved, subtle sequence and/or conformational variations enable drug selectivity, thus facilitating clinical usage. Comparisons of high-resolution structures of complexes of antibiotics bound to ribosomes from eubacteria resembling pathogens, to an archaeon that shares properties with eukaryotes and to its mutant that allows antibiotics binding, demonstrated the unambiguous difference between mere binding and therapeutical effectiveness. The observed variability in antibiotics inhibitory modes, accompanied by the elucidation of the structural basis to antibiotics mechanism justifies expectations for structural based improved properties of existing compounds as well as for the development of novel drugs.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2006년도 Proceedings of The Convention
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• pp.103-115
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• 2006

$\beta$-Glucan is a glucose polymer that has linkage of $\beta$-(1,3), -(1,4) and -(1,6). As exclusively found in fungal and bacterial cell wall, not in animal, $\beta$-glucans are recognized by innate immune system. Dendritic cells (DC) or macrophages possesses pattern recognition molecule (PRM) for binding $\beta$-glucan as pathogen-associated molecular pattern (PAMP). Recently $\beta$-glucan receptor was cloned from DC and named as dectin-l which belongs to type II C-type lectin family. Human dectin-1 is consisted of 7 exons and 6 introns. The polypeptide of dectin-1 has 247 amino acids and has cytoplasmic, transmembrane, stalk and carbohydrate recognition domains. Dectin-1 could recognize variety of beta-1,3 and/or beta-1,6 glucan linkages, but not alpha-glucans. In our macrophage cell line culture system, dectin-1 mRNA was detected in RA W264.7 cells by reverse transcription-polymerase chain reaction (RT-PCR). Dectin-1 was also detected in the murine organs of spleen, thymus, lung and intestines. Treatment of RA W264.7 cells with $\beta$-glucans of Ganoderma lucidum (GLG) resulted in increased expression of IL-6 and TNF-$\alpha$ in the presence of LPS. However, GLG alone did not increase IL-6 nor TNF-$\alpha$. These results suggest that receptor dectin-1 cooperate with CD14 to activate signal transduction that is very critical in immunoresponse.

• 대한의생명과학회지
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• 제14권4호
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• pp.203-210
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• 2008

One of cell surface receptor proteins, human folate receptor (hFR) involves in the uptake of folates through cell membrane into cytoplasm, and is anchored to the plasma membrane by a fatty acid linkage, which has been identified in some cells as a glycosylphosphatidylinositol (GPI)-tailed protein with a molecular mass of about 40 kDa. The hFR is released by phosphatidylinositol phospholipase C (PI-PLC) because it contains fatty acids and inositol on the GPI tail. Caveolin decorates the cytoplasmic surface of caveolae and has been proposed to have a structural role in maintaining caveolae. It is unknown whether caveolin is involved in targeting, and is necessary for the function of GPI-tailed proteins. To compare the ability of folic acid binding, internalization and expression of hFR, and the effect of caveolin at the both apical and basolateral side of cell surfaces in Chinese hamster ovary (CHO) clone cells overexpressed the hFR and/or caveolin. Our present results suggest a possibility that the overexpression of caveolin does not be involved in expression of hFR, but plays a role as a factor in PI-PLC releasing kinetics, and for a regulation of formation, processing and function of hFR in CHO clone cells overexpressed cavcolin.