• Korean journal of food and cookery science
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• v.28 no.1
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• pp.51-55
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• 2012

This study was conducted to investigate the physicochemical properties of citrus peel extracts with different hot water extraction and enzymatic hydrolysis conditions. Enzymatic hydrolysis was also employed using Viscozyme L and results were compared with that of optimized hot water extract. Hot water extraction was performed under different parameters; the sample to solvent ratio(1:20, 1:15, 1:10), extraction time(2, 4 hrs), extraction temperature(85, $95^{\circ}C$) and enzymatic hydrolysis(0, 1%) and the subsequent extracts were used for determining their physicochemical properties, such as total yield, total phenolics, total flavonoids, and electron donating ability (EDA). With the increase in the sample to solvent ratio and extraction time, total yield, total phenolics, total flavonoids and EDA increased. But extraction temperature did not significantly affect the hot water extract. As hot water extract was hydrolyzed by the enzyme, total yield and active ingredients increased rapidly. In the result of total yield, total phenolics, total flavonoids and EDA, the activity of enzyme-treated extract was higher than those of enzyme-untreated extract. Based upon the overall hot water extraction efficiency, it was found that 20 times volume or 120 min at a time at $95^{\circ}C$ after enzyme treatment was optimal.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.3
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• pp.213-219
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• 2013

A field study was conducted to understand nitrogen use efficiency of high yielding Japonica rice varieties under three levels of nitrogen fertilizer (90, 150 and 210 kg N $ha^{-1}$) in Iksan, Korea. Two high yielding rice varieties, Boramchan and Deuraechan, and an control variety, Dongjin2, were grown in fine silty paddy. Nitrogen use efficiencies (NUE) were 83.3, 56.3, and 41.2 in 90, 150, and 210 kg N $ha^{-1}$ fertilizer level, respectively. Total nitrogen uptake varied significantly among nitrogen levels and varieties. Variety Dongjin2 showed the highest nitrogen uptake efficiency (NUpE), while Boramchan and Deuraechan showed higher nitrogen utilization efficiency (NUtE). However, Nitrogen harvest index (NHI) was higher in Boramchan (0.58) than Deuraechan (0.57) and Dongjin2 (0.53). Rough rice yield showed linear relationship with total nitrogen uptake ($R^2$=0.72) within the range of nitrogen treatments. Boramchan produced significantly higher rough rice yield (8546 kg $ha^{-1}$) which mainly due to higher number of panicles per $m^2$ compared to Deuraechan (7714 kg $ha^{-1}$). Deuraechan showed higher number of spikelets per panicle, but showed lower yield due to lower number of panicle per $m^2$. Rice varieties showed different nitrogen uptake ability and NUE at different nitrogen level. Plant breeders and agronomist should take advantage of the significant variations and relationships among grain yield, NUpE, and NUE.

• Microbiology and Biotechnology Letters
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• v.13 no.2
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• pp.119-127
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• 1985

A series of Escherichia coli mutants were exmined for ability to convert glucose and ammonium salts into phenylalanine. This enabled the biochemical changes having major. effects on phenylaianine yield, and interactions between mutations, to be identified. Changes to the common pathway of aromatic biosynthesis having a major effects include desensitization of the first enzyme (3-deoxy-D-arabinoheptulosonate synthase) to end-product inhibition, and removal of repression of enzyme synthesis. It is suggested that the 3-deoxy-D-arabino-heptulosonate synthase Phe isoenzyme has a more important effect on yield. Similarly, removal of repression and end-product inhibition on the phenylalanine terminal pathway increased yield, and changes to both common and branch pathways were synergistic. Blockage of the typrosine and tryptophan pathways had minor effects on phenylalanine yield, and a mutation affecting aramatic amino acid transport (aroP) decreased yield. With multiple-mutation strains hish specific rates of product formation (ie 0.1-0.17g phenylalanine/g cells/h) were obtained.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.252-252
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• 2022

Genotype-by-environment interaction (GEI) refers to the comparative response of genotypes to different environments conditions. Thus, understanding GEI is a fundamental component for selecting superior genotypes for breeding programs. The significance of utilizing early maturing cultivars not only provides flexibility in planting dates, but also serves as an effective strategy to reduce methane emission from the paddy fields. In this study, we conducted multi-environment trials (METs) to evaluate yield-related traits such as culm length, panicle length, panicle number, spikelet per plant, and thousand grain weight. A total of eighty-one Korean commercial rice cultivars categorized as early maturing cultivars, were cultivated in three regions, two planting seasons for two years. The genotype main effect plus genotype-by-environment interaction (GGE) biplot analysis of yield-related traits and grain yield explained 70.02-91.24% of genotype plus GEI variation, and exhibited various patterns of mega-environment delineation, discriminating ability, representativeness, and genotype rankings across the planting seasons and environments. Moreover, simultaneous selection using weighted average of absolute scores from the singular value decomposition (WAASB) and multi-trait stability index (MTSI) revealed six highly recommended genotypes with high stability and crop productivity. The winning genotypes under specific environment can be utilized as useful genetic materials to develop regional specialty cultivars, and recommended genotypes can be used as elite climate-resilient parents to improve yield-potential and reduce methane emission as part to accomplish carbon-neutrality.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.374-377
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• 2001

On the basis of high-osmotic tolerance and xylitol productivity, it was isolated a novel strain from soil of rice field. An isolated strain was tentatively designated as Candida sp. HY200, deduced from the systematic approaches of bacterial identification by Biolog $Microlog^{TM}$ and, revealed an interesting ability of flocculation during the cultivation. With respect to the osmotic-tolerance and flocculation ability, experiment was carried out to investigate the production of xylitol in high xylose concentration. When xylose concentration was 260 g/L, it was obtained 205 g/L xylitol with 79% of yield and 2.14 g/L ${\cdot}$ h of productivity Consequently, We convinced that Candida sp. HY200 stands a very favorable comparison with C. tropicalis.

• Journal of the Korean Society of Tobacco Science
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• v.4 no.1
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• pp.21-27
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• 1982

Six flue-cured cultivars of Nicotiana tabacum L., 15 possible $F_1$ hybrids and 15 $F_2$ populations among them, and 15 haploid populations of $F_1$ hybrids and 6 haploid from parents, were evaluated. The variances of general combining ability were predominant for all characters studied in $F_1$ hybrid and $F_2$ population, and in haploid populations of $F_1$ hybrids except leaf width, value and reducing sugar. There were significant correlations between generations in variances and ranks of parental GCA effects estimated from general combining ability analysis of $F_1,\;F_2$ and haploid generation of $F_1$ hybrids for yield, stem height, days to flower. leaves per plant, value and total alkaloids.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.269-270
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• 2018

Urea is liquefied when it is dissolved in water and has the effect of increasing water. It is known that when using urea, it is generally possible to reduce the number of design units in order to ensure the same flow-ability, because the effect of increasing the water when using urea in the manufacturing of concrete is known. In this study, the change of basic properties of concrete when using urea was investigated in concrete production, and the effect of reducing the unit yield was confirmed.

• Mycobiology
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• v.31 no.4
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• pp.209-213
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• 2003

Aspergillus flavus K-03 isolated from poultry forming soil in Korea was studied for its ability to produce extracellular proteases on basal medium containing 2%(w/v) chicken feathers. The fungus was observed to be a potent producer of such enzymes. Keratinolytic enzyme secretion was the best at 15 days of incubation period at pH 9 and temperature $40^{\circ}C$. No relationship existed between the enzyme yield and increase of biomass. Enzyme production was suppressed by exogenous sugars in descending order arabinose>maltose>mannose>fructose. But glucose did not influence the enzyme activity. The keratinolytic enzyme released by the fungus demonstrated the ability to decompose keratin substrates as chicken feather when exogenous glucose was present. The keratinolytic activity was inhibited by $HgCl_2$ and serine-protease inhibitors such as phenymethylsulfonyl fluoride(100%), chymostain(88%), crystalline soybean trypsin inhibtor(80%), antipain(45%) and aprotinin(40%), and was not by cystein-protease and aspartyl-protease inhibitors. The enzyme activity is only partially inhibited by metallo-protease inhibitor. Thus, the enzyme secreted by A. flavus K-03 belongs to the alkaline serine-type protease.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.211-216
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• 2007

The objective of this paper is to present the results of an experimental and a finite-element investigation into the behavior of X80 grade pipes subjected to bending. For the pipe specimens comprising the test series, different D/t is applied to be representative of those that can be expected in the field. Results from the numerical models are checked against the observations in the testing program and the ability of numerical solutions to predict pipe moment capacity. curvatures. and buckling modes is established. A finite-element model was developed using the finite-element simulator to predict the local buckling behavior of pipes. The comparison between the numerical and the experimental results demonstrates the ability of the analytical model to predict the local buckling behavior of pipes when deformed well into the post-yield range.

• Macromolecular Research
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• v.17 no.7
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• pp.522-527
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• 2009

A photocrosslinkable polyphosphazene was used for molecular imprinting. We synthesized polyphosphazene (3) having urea groups for complexation with N-carbobenzyloxyglycin (Z-Gly-OH, template) and chalcone groups for cross-linking reaction. As substituents, 4-hydroxycha1cone (1) and N-(4-hydroxyphenyl)-N'-ethylurea (2) were prepared. Choloro groups of poly(dichlorophosphazene) were replaced by the sequential treatment with sodium salts of compounds 1 and 2, and trifluoroethanol. The template molecule was complexed with the urea groups on the polymer chains via hydrogen bonding. A thin polymer film was prepared by casting a solution of the complex of polymer 3 and the template in dimethylformamide on a quartz cell and irradiated with 365 nm UV light to yield a cross-linked film with a thickness of about $16{\mu}m$. The template molecules in the film were removed by Soxhlet extraction with methanol/acetic acid. The control polymer film was prepared in the same manner for the preparation of the imprinted polymer film, except that the template and triethylamine were omitted. In the rebinding test, the imprinted film exhibited much higher recognition ability for the template than the control polymer. We also investigated the specific recognition ability of the imprinted polymer for the template and its structural analogues. The rebinding tests were conducted using Z-Glu-OH, Z-Asp($O^tBu$)-OH, and Z-Glu-OMe. The imprinted film showed higher specific recognition ability for the template and the lowest response for Z-Asp($O^tBu$)-OH.