• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.234-234
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• 2010

The PR transitions in asymmetric dot-in-double-quantum-well (DdWELL) photodetector is identified by bias-dependent spectral behaviors. Discrete n-i-n infrared photodetectors were fabricated on a 30-period asymmetric InAs-QD/[InGaAs/GaAs]/AlGaAs DdWELL wafer that was prepared by MBE technique. A 2.0-monolayer (ML) InAs QD ensemble was embedded in upper combined well of InGaAs/GaAs and each stack is separated by a 50-nm AlGaAs barrier. Each pixel has circular aperture of 300 um in diameter, and the mesa cell ($410{\times}410\;{\mu}m^2$) was defined by shallow etching. PR measurements were performed in the spectral range of $3{\sim}13\;{\mu}m$ (~ 100-400 meV) by using a Fourier-transform infrared (FTIR) spectrometer and a low-noise preamplifier. The asymmetric photodetector exhibits unique transition behaviors that near-/far-infrared (NIR/FIR) photoresponse (PR) bands are blue/red shifted by the electric field, contrasted to mid-infrared (MIR) with no dependence. In addition, the MIR-FIR dual-band spectra change into single-band feature by the polarity. A four-level energy band model is proposed for the transition scheme, and the field dependence of FIR bands numerically calculated by a simplified DdWELL structure is in good agreement with that of the PR spectra. The wavelength shift by the field strength and the spectral change by the polarity are discussed on the basis of four-level transition.

• Korean Journal of Organic Agriculture
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• v.12 no.2
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• pp.219-230
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• 2004

In recent years, the consumption of livestock products were markedly decreased by awareness of world-widely occurred diseases including mad cow disease, Foot and mouth disease, Hog cholera, and Poultry Influenza virus. the consumers ara also wanting to have highly safe food such as organic animal products because of concerning about residual of antibiotics in animal products. However, disease control and impairment of productivity are the major problem in organic animal production. On these points of view, the present study was undertaken to investigate the effects of 1% or 2% of dietary probiotics fortified with various minerals on improvement of egg production and egg quality in old lay6r feeding low quality feed mainly composed of food waste, sesame meal, and rice bran. After 4 weeks of experimental feeding, the diameter of spreading of egg white was clearly decreased from 11.2cm of control eggs to 10.5m and 10.1m in 1% and 2% treatment group eggs, respectively. The color of egg yolk was 9.3 in control eggs but remarkably increased in treatment groups showing 10.1~10.2. Egg production was 75.8% in control layers but significantly increased to 79.8% of 1% treatment group and 82.9% of 2% treatment group layers. Egg weights (C : 66.3g, 1% : 73.2g, and 2% : 76.7g) and egg shell thickness (C : 0.33mm, 1% : 0.35mm and 2% : 0.36mm) were also increased by the addition of 1% or 2% of probiotics when compared to those of control group eggs. All together, it has been suggested that dietary addition of probiotics fortified with various minerals can improve the egg quality and egg production in layer's productivities by the recycling of organic waste resources such as food waste and agricultural by-products.

• Molecules and Cells
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• v.28 no.2
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• pp.119-124
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• 2009

Anti cancer agent 5-FU (Fluoro Uracil) is a prodrug that can be metabolized and then activated to interfere with RNA and DNA homeostasis. However, the majority of administered 5-FU is known to be catabolized in vivo in the liver where Dihydropyrimidine dehydrogenase (DPD) is abundantly expressed to degrade 5-FU. The biological factors that correlate with the response to 5-FU-based chemotherapy have been proposed to include uridine phosphorylase (UPP), thymidine phosphorylase (TPP), p53 and microsatellite instability. Among these, the expression of UPP is known to be controlled by cytokines such as $TNF-{\alpha}$, IL1 and $IFN-{\gamma}$. Our preliminary study using a DNA microarray technique showed that basic fibroblast growth factor (bFGF) markedly induced the expression of UPP1 at the transcription level. In the present study, we investigated whether bFGF could modulate the expression of UPP1 in osteo-lineage cells and examined the sensitivity of these cells to 5-FU mediated apoptosis.

• Journal of Food Hygiene and Safety
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• v.24 no.1
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• pp.27-37
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• 2009

In an effort to evaluate the currents in pesticide residues, 3,020 agricultural products were tested by multiresidue method with 260 pesticides, obtained from the circulation market of in the Gangbuk province in 2007.20.4%(616/3020) of the products were determined to contain pesticides residues, but only 4.1%(124/3020) of these were deemed to be unsuitable by the korea Food Code. Unsuitably products were spinach(21.0%), perilla leaf(17.3%), ulgari(13.6%), leek(12.4%), crowndaisy(12.4%), asterscaber(12.4%), chard(11.1%). Detected pesticides were procymidone(3.9%), endosulfan(2.6%), chlorfenapyr(2.2%), bifenthrin(1.3%), cypermethrin(0.7%), metalaxyl(0.9%), azoxystrobin(0.3%) and chlorothalonil(0.7%). Sixty-four pesticides were detected and 11 pesticides were newly detected in 2007. Thirty-one pesticides in agricultural products exceeded their MRLs.

• Korean Journal of Food Science and Technology
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• v.19 no.2
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• pp.146-150
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• 1987

The effects of pH and added salts on the partition coefficients of proteins in a polyethylene glycol)-dextran aqueous two-phase system were investigated. The partition coefficients attained the lowest value at the isoelectric point of proteins in an equal volume aqueous two-phase system containing 5% PEG and 9.5% dextran in 5 mM phosphate buffer solution. The coefficients increased dramatically at pH 11; BSA which had highest effective hydrophobicity marked 50-fold increase, while ${\beta}-lactoglobulin$ and ovalbumin which had low hydrophobicity 10-fold increase, respectively. The effect of added salts varied with the pH. The partition coefficient increased by the addition of salt at pH 3.0 but decreased drastically at pH 7.0. The partition coefficient increased in the order of added Li < Na < K at pH 3.0 and decreased in the order of added Li < Na < K at pH 11.0.

• Korean Journal of Food Science and Technology
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• v.19 no.2
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• pp.140-145
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• 1987

The partition coefficient of the proteins of known effective hydrophobicity was determined in a poly (ethylene glycol)-dextran aqueous two-phase system. The changes in the partition coefficient was also determined when a fraction of PEG-palmitate (PEG-P) was added to the system. The partition coefficient of the proteins increased as the concentrations of PEG and dextran increased at a constant phase volume ration irrespective of the effective hydrophobicity of the proteins. When small amounts of PEG-P were added to the PEG phase, the partition coefficients of BSA and ${\beta}-lactoglobulin$, which had relative hydrophobicity (RI) of 700 and 120, respectively, increased more than ten-fold, whereas ovalbumin whose RI was 5 showed little change. The drastic increases m the partition coefficient were observed by the addition of PEG-P in 2% level to the PEG system. Addition of PEG-P over 5% level resulted in a slight further increase in the partition coefficient of all proteins tested.

• Natural Product Sciences
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• v.9 no.2
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• pp.112-116
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• 2003

The antitumor and immunostimulating activities of Acanthopanax sessiliflorus fruits were investigated. Polysaccharide isolated from this plant, when administered consecutively for 9 days at 50 and 100 mg/kg i.p. in mice, caused a significant increase in the life span and a significant decrease in the tumor weight and volume in mice inoculated with Sarcoma-180 tumor cells. Polysaccharide was also demonstrated to exhibit phagocytosis-enhancing activity as measured by the carbon clearance in mice. Polysaccharide, when administered i.p. at 50 and 100 mg/kg/day for 3 consecutive days, exhibited a significant RCtr/RCc [the rate of regression coefficient of the animals teated (RCtr) to that of the control (RCc)], being 1.44 (PI = 1), 1.52 (PI = 2) which was approximately the same with that of enhancement of phagocytosis, its potency as expressed by the regression coefficient ratio of zymosan (RCtr/RCc = 1.55, PI = 2), a typical phagocytosis enhancer. Polysaccharide also caused a significant increase in the acid phosphatase activity representing lysosomal enzymes in macrophages at 1-100 ig/ml in vitro in compliance with in vivo results. These results suggest that the antitumor activity of polysaccharide might be related to the immunostimulating function.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.1
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• pp.73-77
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• 2002

The Sec61 trimeric complex ($\alpha$,$\beta$, and ${\gamma}$ subunits) is one of the Sec-complex responsible for post-translational protein translocation across the endoplasmic reticulum membrane in diverse organisms. In this study, a cDNA encoding the Sec61p ${\gamma}$ subunit homologue was isolated from the cDNA library of the mole cricket, Gryllotalpa orientalis. Sequence analysis of a 442-bp cDNA clone showed it to contain an open reading frame of 68 amino acid residues consisted of 204-bp. The homologues of the gene were found in the GenBank database in a diverse organism including insect, mammals, fungi, and plants. The deduced amino acid sequence of Sec61p ${\gamma}$ subunit homologue of the mole cricket showed the highest homology to the gene of the singly known insect, Drosophila melanogester (93% identity), and the least homology to that of the baker's yeast, Saccharomyces cerevisiae (37.2%). Phylogenetic analysis also confirmed a close relationship between the insect Sec61p ${\gamma}$ subunit homologues of G. orientalis and D. melanogester. Hydropathy analysis of the cricket mole and published other data suggested that the hydrophobic segment close to C-terminus is predicted to be the putative membrane anchor, Multiple alignment of the Sec61p ${\gamma}$ subunit homologue among several organisms showed the presence of several conserved domains including the conserved proline at position 28.

• International Journal of Industrial Entomology and Biomaterials
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• v.16 no.1
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• pp.7-13
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• 2008

We investigated mating conditions about care temperature of queen before mating, mating period, and number of queen per mating cage to improve mating rate of Bombus terrestris. Among $19^{\circ}C$, $22^{\circ}C$ and $25^{\circ}C$, care temperatures of queen before mating, queen cared at $19^{\circ}C$ was more effective than those at $22^{\circ}C$ and $25^{\circ}C$ in death rate during care and mating periods, and colony development In case of mating period, oviposition rate and preoviposition periods at queen mated during 3 days were 89.3% and 11.4 days, respectively, which was higher and earlier than those of queen mated during 5 days and 7 days. The rate of worker emergence, colony foundation and progeny-queen production at 3 days-mated queen were also 2.0-11.6% higher than those at queen mated during 5 days and 7 days. In number of queen per mating cage, the rate of worker emergence, colony foundation and progeny-queen production queen mated at mating cage with 10 queens and 30 males were 41.5%, 25.9% and 23.2%, respectively. These values correspond to 1.5-6.8 folds those queen mated at cage with 20 queens and 30 queens. Therefore, we supposed that care temperature favorable for B. terrestris queen was $19^{\circ}C$ and the period need to mating was 3 days, and the number of queen per mating cage ($55{\times}45{\times}65\;cm$) was 10.

• Journal of Wetlands Research
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• v.14 no.2
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• pp.277-288
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• 2012

Estuary is unique habitat ground under substantial changes of water quality, river side, bed material, and micro topography. Construction of SinGok underwater weir with excessive dredging for downstream of weir has changed hydraulic conditions of Han River. This study investigates spatial changes of estuary and expansion process of vegetation on sandbar for JangHang estuary in Han River through analysis of physical and ecological characteristics. As a result of investigation, we found that area of sandbar in JangHang estuary is expanded six times compared between 1985 and 2006, and area of Phragmites australis is gradually decreased while area of Salix subfragilis Anderson. is increased. Also the analysis result of soil layer shows that the Jang-Hang wetlands are created by effect from river, and woody plants are settled from middle part of wetlands, then spread to upper and lower part of wetlands.