• Journal of Korean Society of Forest Science
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• v.78 no.4
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• pp.401-411
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• 1989

The embryos of Pinus taeda, P. rigida, and P. taeda ${\times}$ rigida were cultured for adventitious shoot regeneration in vitro. Culture media were modified from Gresshoff and Doy (MGD), Murashige and Skoog (MMS), Lloyd and McCown (MLM), and Schenk and Hildebrandt (MSH). NAA was added to initiation media at a concentration of 0.1 or 0.01 mg/l. BAP was used at the concentrations of 0.1. 0.5, 1, 2, or 5mg/l. Each explant was induced for 3-4 weeks on solid medium. All explants were cultured up to 16 weeks. Illumination was about $1506{\pm}540lux$ at the level of the tissues in the growth room with a temperature of $25{\pm}2^{\circ}C$. A 16-hour photoperiod per 24 hours was used. Half-strength medium was used for all the subcultures. For shoot production by loblolly pine, MMS, MLM, or MSH is preferred with 5 mg/l BAP with either 0.1 or 0.01 mg/l NAA. For shoot production by pitch pine, MMS, MLM, or MSH is recommended with 2 or 5 mg/l BAP with 0.1 mg/l NAA. For shoot production by the hybrid pine, MMS or MLM is more effective with 1, 2 or 5 mg/l BAP with 0.1 mg/l NAA. There were no differences recognized among the species tried in the patterns of bud formation and shoot development. Different composition of media, in major and minor salts or possibly in vitamins, should be tested for the two developmental stages of adventitious shoots ; the induction of shoot buds and the elongation of them into shoots.

• Phonetics and Speech Sciences
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• v.4 no.3
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• pp.31-41
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• 2012

Recent studies have shown that the stop system of Korean is undergoing a sound change in terms of the two acoustic parameters, voice onset time (VOT) and fundamental frequency (f0). Because of a VOT merger of a consonantal opposition and onset-f0 interaction, the relative importance of the two parameters has been changing in Korean where f0 is a primary cue and VOT is a secondary cue in distinguishing lax from aspirated stops in speech production as well as perception. In English, however, VOT is a primary cue and f0 is a secondary cue in contrasting voiced and voiceless stops. This study examines how Korean English learners use the two acoustic parameters of L1 in producing L2 English stops and whether the sound change of acoustic parameters in L1 affects L2 speech production. The data were collected from six adult Korean English learners. Results show that Korean English learners use not only VOT but also f0 to contrast L2 voiced and voiceless stops. However, unlike VOT variations among speakers, the magnitude effect of onset consonants on f0 in L2 English was steady and robust, indicating that f0 also plays an important role in contrasting the [voice] contrast in L2 English. The results suggest that the important role of f0 in contrasting lax and aspirated stops in L1 Korean is transferred to the contrast of voiced and voiceless stops in L2 English. The results imply that, for Korean English learners, f0 rather than VOT will play an important perceptual cue in contrasting voiced and voiceless stops in L2 English.

• BMB Reports
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• v.32 no.5
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• pp.480-485
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• 1999

Tyrosine phenol-lyase of thermophilic Symbiobacterium sp. SC-1, which is obligately and symbiotically dependent on thermophilic Bacillus sp. SK-1, was purified and characterized. The enzyme is composed of four identical subunits and contains approximately 1 mol of pyridoxal 5'-phosphate (PLP) per mol subunit as a cofactor. The enzyme showed absorption maxima at 330 and 420 nm, and lost this absorption profile by treatment with phenylhydrazine. The apparent dissociation constsnt, $K'_D$, for PLP was determined with the apoenzyme to be about $1.2\;{\mu}M$. The isoelectric point was 4.9. The optimal temperature and pH for the $\alpha,\beta$-elimination of L-tyrosine were found to be $80^{\circ}C$ and pH 8.0, respectively. The substrate specificity of the enzyme was very broad: L-amino acids including L-tyrosine, 3,4-dihydroxyphenyl-L-alanine (L-DOPA), L-cysteine, L-serine, S-methyl-L-cysteine, $\beta$-chloro-L-alanine, and S-(o-nitrophenyl)-L-cysteine all served as substrates. D-Tyrosine and D-serine were also decomposed into pyruvic acid and ammonia at rates of 7% and 31% relative to their corresponding L-enantiomers, respectively. D-Alanine, which was inert as a substrate in a, $\beta$-elimination, was the only D-amino acid racemized by the enzyme. The $K_m$ values for L-tyrosine, L-DOPA, S-(o-nitrophenyl)-L-cysteine, $\beta$-chloro-L-alanine, and S-methyl-L-cysteine were 0.19, 9.9, 0.36, 12, and 5.5 mM, respectively.

• Journal of Plant Biotechnology
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• v.33 no.2
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• pp.99-104
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• 2006

This study was performed to investigate regeneration of plants differentiated from hybrid embryos between L. longifilorum Georgia and L. elegans Kakutanohikari. In addition, proliferation of callus and process of differentiation were investigated by histological observation. The germination of hybrid embryos was observed in 86 individuals from 48 slice cultures. Plant regeneration was effective on a medium supplemented with 1 mg/L HPh, and only callus proliferation was the highest in combination of 0.1 mg/L HPh and 1 mg/L BA. Also, plant regeneration was the most effective on a medium supplemented with 50 mg/L pyridoxine. We concluded that somatic embryos were formed from procambium of callus and proliferation of embryonic or proembryonic cells were stimulated with NAA from procambial cells.

• Membrane and Water Treatment
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• v.4 no.1
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• pp.1-9
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• 2013

The process of electromembrane transformation of L-lysine monohydrochlorides into their zwitterionic form in four- and two-chamber electrodialysis apparatus was investigated. The process of transformation at various concentrations of lysine monohydrochloride (0.1-0.6 mol.L-1) was studied and it was established that at the optimum density of current optimal concentrations of lysine hydrochloride during electrodyalisis was in the range of 0.2-0.4 mol.L-1. It was determined that the process of total transformation was accomplished when pH of the lysine solution achieved 10. Changes of concentrations of $Cl^-$ ions and lysine diffused into the neighboring chamber were determined depending on the time. The method developed by us allows adjusting the removal coefficient of $Cl^-$ ions during transformation to a maximal value, the losses of lysine diffused into the next chamber after its return to the technological cycle being less than 1.0 %. The specific energy consumption during the process of transformation in two- and four-chamber electrodialyzers was 0.19 and 0.205 A.h.kg-1 and the current efficiency was 75.9 and 73.1 %, correspondingly. Study of the process of electromembrane transformation allowed obtaining zwitterionic form of L-lysine from L-lysine monohydrochloride with minimal reagent and energy consumption.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.6
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• pp.541-545
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• 2000

This study examines the effects of alginic acid, a source of dietary fiber, in a glucose-derived media. In particular, we examined how the presence or absence of alginic acid affected the differentiation and triglyceride densities of 3T3-L1 cells. We established that the addition of insulin-like growth factor-I (IGE-I) to 3T3-L1 cells results in acceleration of differentiation. We sought to determine the role of alginic acid in the production of fat by adding alginic acid to 3T3-L1 cells and examining its ability to limit or potentiate this stimulatory effects of IGE-I and IGF binding proteins. We have determined that alginic acid restricts 3T3-L1 cell differentiation and the creation of triglycerides, effectively attenuating 3T3-L1 cell metablolism and growth.

• ALGAE
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• v.22 no.3
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• pp.193-199
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• 2007

This study was carried out to investigate the charateristics of environmental factors and the species compositions of phytoplanktons and periphytons in order to analyze the marine ecosystem (DOK1-3) with freshwater (Mul) in the coast of Dokdo. Mean values of conductivity (TSD) (44.3 mS cm–1), total dissolved solids (30.9 mg L–1), salinity (31.8 psu), total suspended solids (39.2 mg L–1), and ash-free dry matter (AFDM) (8.8 mg L–1) were higher in DOK1- 3 than those in Mul (3.2 mS cm–1, 2.3 mg L–1, 1.9 psu, 2.8 mg L–1 and 2.8 mg L–1, espectively), while mean amounts of soluble reactive phosphorus (SRP) (7.5 μg P L–1) and soluble reactive silicon (SRS) (0.1 μg Si L–1) were significantly lower in DOK1-3 than those in Mul (117.3 μg P L–1 and 4,105 μg Si L–1, respectively). The phytoplanktons was a total of 59 species in Dokdo, which were composed of 1 species (1.7%) for Chrysophyceae, 43 species (72.9%) for Bacillariophyceae and 15 species (25.4%) for Dinophyceae. The biomass (Chl-a, phaeopigment and AFDM) of epilithic algae (ELA), epizooic algae (EZA) and epiphytic algae (EPA) were varied with the kinds of substrates (EPA > ELA > EZA) in the whole stations. Water environments was comparatively clean in the coast of Dokdo as comparing with those of the land. However, the monitoring of marine ecosystem in the Dokdo should be continued for species conservation according to the global warming by the climatic change.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.8
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• pp.1257-1261
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• 2004

Antioxidant activities of traditional liquors produced in Chungcheong-do were studied. The contents of organic acids, carbohydrate, and protein of the traditional liquors were 0.30~0.95%, 1.4~11.1% and 1.5~37.3 mg%, respectively. Especially, the contents of phenolic compounds of L-3 was the highest (205.8 $\mu\textrm{g}$/mL). L-5, L-4 and L-3 showed higher antioxidant activities than the others on hemoglobin-induced linoleic acid system. L-5 also showed high reducing power and scavenging effect on DPPH radical. Scavenging effects on hydroxyl radicals in L-6, L-5 and L-4 showed higher activities (42~53%) than those of the others. The highest scavenging effect on superoxide anion radical was observed in L-5 ($IC_{50}$/: 1.1 $\mu\textrm{g}$).

• KSBB Journal
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• v.5 no.4
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• pp.383-390
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• 1990

Alcoholic distillery waste was utilized as dual purposes to produce citric acid and to reduce the amount of waste to be treated. Enzyme and acid hydrolysis of this waste were studied to suggest effective way of present purpose. Enzymatic hydrolysis of this naked barley alcoholic distillery waste by $\alpha$-and $\beta$-amylase gave glucose as 8g/l concentration at $55^{\circ}C$ for 6 hours, which produced 1g/l citric acid and 5.33g/l mycelial. This waste material hydrolyzed with 25% HCl at $120^{\circ}C$ showed 21.5g/l glucose and produced 1.75g/l citric acid with 4.9g/1 mycelial. The glucose concentration was decreased to 3.44g/l by further 2nd acid hydrolysis because the monosugars were decomposed at prolonged hydrolysis conditions. The addition of 3g/l $NH_4NO_3$ increased the mycelial growth but reduced the amount of citric acid formed. The formation of citric acid was increased at low concentration of manganese ion.

• Journal of the Chungcheong Mathematical Society
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• v.8 no.1
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• pp.105-110
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• 1995

Suppose A is a local global ring (with many units) and $T{\subset}A$ is a preordering. Let $a_i{\in}A^*$, $i=1,2,{\cdots},n$ and $a{\in}({\sum}_{i=1}^{l-1}\;a_iT){\cap}A^*$. Then, for any integer l, 1 < l ${\leq}$ n, there exist $x{\in}({\sum}_{i=1}^{l-1}\;a_iT){\cap}A^*$ and $y{\in}({\sum}_{i=l}^n\;a_iT){\cap}A^*$ such that a=x+y.