• Journal of Korean Tunnelling and Underground Space Association
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• v.10 no.1
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• pp.69-79
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• 2008

Prediction of ground condition ahead of tunnel face might be the most important factor to prevent collapse during tunnel excavation. In this study, a non-destructive method to evaluate the phase velocity in model rock mass using wavelet transform of surface wave was proposed aiming at ground condition assessment ahead of tunnel face. Model tests using gypsum as a rocklike material composed of two layers were performed. A Piezoelectric actuator with frequencies ranging from 150 Hz to 5 kHz was selected as a harmonic source. The acceleration history was measured with two accelerometers. Wavelet transform analysis was used to obtain the dispersion curves from the measured data. The experimental results showed that the near-field effects can be neglected if the distance between two receivers is chosen to be three times the wavelength. A simple inversion method using weighted factor based on the normal distribution was proposed. The inversion results showed that the predicted phase velocity agreed reasonably well with the measured one when the wavelength influence factor was 0.2. The depth of propagation of surface wave was from 0.42 to 0.63 times the wavelength. The range of wavelength varying with phase velocity in dispersion curve matched well with that estimated by inversion technique.

• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.6
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• pp.431-450
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• 2011

When a circular vertical shaft is constructed below the groundwater level, additional forces caused by groundwater flow besides horizontal effective stresses will act on the wall. The inward direction of the groundwater flow will be inclined to the vertical wall and its direction will change depending on the wall depth. In this paper, to figure out the effect of seepage forces acting on the circular vertical shaft, the slope of the inclined flow varying with the depth is divided into vertical and horizontal components to derive the coefficient of earth pressure considering the seepage pressure and to obtain the vertical stress by taking the seepage pressure into account. The control volume in this study is assumed to be the same with that of the dry ground condition within which the earth pressure is acting on the wall by the creation of the plastic zone during shaft excavation. An example study shows that the vertical stress increases by about 1.4 times and the horizontal earth pressure increases up to 2.5 times compared to the dry ground condition. The estimated values from the proposed equation considering seepage forces and the calculated values from numerical analysis with "effective stress plus seepage force" show similar values, which verifies appropriateness of the proposed equation to estimate the earth pressure under the seepage condition.

• Korean Journal of Plant Tissue Culture
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• v.28 no.3
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• pp.159-164
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• 2001

To produce novel bioactive flavonoids, Gericudranin A and Gericudranin B, a cell culture system of Cudrania tricuspidata including callus induction and optimization of culture conditions was established. Friable calli were efficiently induced from the hypocotyl segments of seedlings on B5 medium supplemented with 1.0 mg/L NAA, 0.1 mg/L kinetin and 3% sucrose. Several factors were optimized for the Gericudranin production and the cell growth in suspension cultures. Low level of basal salt medium (1/8 MS), 1.0 mg/L IAA and 0.1 mg/L zeatin, and high level of sucrose (5%) were effective for the production of Gericudranins, whereas WPM with 1.0 mg/L NAA, 0.1 mg/L zeatin, and 5% sucrose were more effective for the cell growth. When cells were cultured on MS liquid medium supplemented with 1.0 mg/L IBA, about 2200 $\mu\textrm{g}$/g dry wt of Gericudranin A could be produced. The level might be about 10 times of the native inner bark. About 2350 $\mu\textrm{g}$/g dry wt of Gericudranin B was also produced on MS liquid medium with 5% sucrose, 1.0 mg/L NAA, 0.1 mg/L kinetin. The content was estimated about 3 times of the level of native inner bark.

• Journal of Plant Biotechnology
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• v.45 no.1
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• pp.63-70
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• 2018

Brazzein is the smallest sweet protein and was isolated from the fruit pulp of Pentadiplandra brazzeana Baillon, native to tropical Africa. From ancient times, the indigenous people used this fruit in their diet to add sweetness to their daily food. Brazzein is 500 to 2000 times sweeter than sucrose on a weight basis and 9500 times sweeter on a molar basis. This unique property has led to increasing interest in this protein. However, it is expensive and difficult to produce brazzein other than in its native growing conditions which limits its availability for use as a food additive. In this study, we report high production yields of, brazzein protein in transgenic rice plants. An ORF region encoding brazzein and driven by the $2{\times}CaMV\;35S$ promoter was introduced into rice genome (Oryza sativa Japonica) via Agrobacterium-mediated transformation. After transformation, 17 regenerated plant lines were obtained and these transgene-containing plants were confirmed by PCR analysis. In addition, the selected plant lines were analyzed by Taqman PCR and results showed that 9 T0 lines were found to have a single copy out of 17 transgenic plants. Moreover, high and genetically stable expression of brazzein was confirmed by western blot analysis. These results demonstrate that recombinant brazzein was efficiently expressed in transgenic rice plants, and that we have developed a new rice variety with a natural sweetener.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.6
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• pp.1197-1203
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• 2001

This study was conducted to examine the effects of dietary xylooligosaccharide on UDP-glucuronyl transferase (UDP-GTase) activity and excretion of fecal sterols in rat fed high cholesterol diet. Sprague-Dawley male rats weighing 100$\pm$10 g were randomly divided into five groups, one with normal diet and four with high cholesterol diets containing 1% cholesterol (w/w). The high groups with cholesterol diet groups were classified into xylooligosaccharide free diet (C), 5% xylooligosaccharide diet (C5XO), 10% xylooligosaccharide diet (C10XO), and 15% xylooligosaccharide diet (C15XO) group according to the five groups of dietary xylooligosaccharide by weights. The experimental diets were fed ad libidum for 4 weeks. Fecal weights were increased 86% by xylooligosaccharide. Fecal total lipid contents including fecal neutral and acidic sterols in xylooligosaccharide groups were significantly higher than those of the normal and C groups, and especially that of C10XO group was the highest among all experimental groups. Activity of UDP-glucuronyl transferase (UDP-GTase) in liver in C group was 35% higher than that of normal group and the activities in C5XO, C10XO and C15XO groups were 15%, 41%, and 21% higher than in C group, respectively. Fecal bile acid excretions per day were increased 3.1, 3.6 and, 2.8 folds in C5XO, C10XO, and C15XO groups, respectively, compared with that of C group. Contents of neutral sterol, coprostanol, and coprostanone were higher in xylooligosaccharide groups than in C group. These results suggest that dietary xylooligosaccharide may act as potential substitute for a dietary fiber capable of improving a gastrointestinal function and lipid metabolism.

• Journal of Korean Society of Forest Science
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• v.104 no.1
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• pp.67-75
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• 2015

This research is to investigate the four years growth mountain-cultivated ginseng ripened twenty-two weeks into four years fermented persimmon vinegar (tentatively: Sansamcho) ingestion on obese-related factors during dietary control. The Sansamcho was ingested orally, two times a day, after every meal for six weeks to the male rats. Groups were divided into the control (CON), the restricted diet (RD), and the weight cycling (WC). And, each groups has its own sub-groups as the -control (-CON), 2.5 times diluted Sansamcho ingestion (-MPV2.5), and 5.0 times diluted Sansamcho ingestion (-MPV5.0) groups, respectively. The number of rat was consisted of seven in each group. After six weeks rearing periods was done, abdominal fats (retroperitoneal fat, mesentery fat, and epididymal fat) and energy metabolic-related protein (AMPK: AMP-activated protein kinase; PPAR-${\alpha}$: peroxisome proliferator-activated receptor-${\alpha}$; and CPT-1: carnitine palmitoyltransferase-1) were weighed and analyzed. Amount of stored fat was significantly or tended to decrease by Sansamcho ingestion. In addition, sum of fats increasing were suppressed by the material. On the contrary, energy metabolism-related protein expression was significantly increased or tended to increase by Sansamcho ingestion. This results suggested that increased energy metabolism using Sansamcho was restrained effectively visceral fat store by high-fat diet and/or dietary control. In other words, it has a good function to suppress weight cycling which is the most insoluble problem. Therefore, the fusion material, Sansamcho, may expect to utilize as the obese-suppression-food.

• Korean Journal of Food Science and Technology
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• v.37 no.2
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• pp.261-267
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• 2005

Phase II enzymes are transcriptionally induced by synthetic chemical agents and natural products, and such induction plays critical roles in protection against chemical carcinogens and other toxic xenobiotics. To discover natural products for use as cancer chemopreventive agents, the ability of Citrus aurantium Linn (Jikak) to induce activities of quinone reductase (QR) and glutathione S-transferase (GST) in wild-type murine hepatoma cell line (Hepa 1c1c7) and Ah-receptor-defective mutant of the same cell line (Bprcl) was investigated. Hexane and chloroform fractions of C. aurantium Linn (Jikak) at doses not exhibiting cytotoxicity were effective inducers of QR (${\sim}1.8-fold$) and GST (${\sim}1.5-fold$) in Hepa 1c1c7 cells, whereas showed low QR induction potency in Bprcl cells, which indicates they have weak monofunctional action. Results suggest C. aurantium Linn (Jikak) as potentially useful cancer chemopteventive agent.

• Korean Journal of Plant Tissue Culture
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• v.25 no.4
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• pp.277-282
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• 1998

Whereas cationic extracellular peroxidases (PODs) were observed in the suspension cultures of rose (Rosa sp. L. cv Pual's scarlet) grown under normal conditions, new anionic isozymes were induced within 24 hr by the treatment of low host-specific elicitor (10 mg glucan/L media) prepared from yeast cell wall. Prominent anionic (pI 6.1) and cationic POD (pI 8.4) were purified and characterized to understand the physiological role of the enzymes. Both enzymes were purified (ca.200 fold) by the ammonium sulfate precipitation, ion exchange chromate-graphy and gel filtration chromatography. The Km values of the purified anionic POD for ferulic acid and $\textrm{H}_2\textrm{O}_2$ were 4.64 mM and 0.72 mM, whereas those of the cationic POD were 1.38 mM and 0.48 mM, respetively. The activity of the anionic POD as NADH oxidase was twice higher than that of cationic POD. The NADH oxidation in the anionic POD fraction was inhibited by 60% on the addition of 0.1 mM coniferyl alcohol, while that in the cationic fraction was inhibited by 15%.

• Asian Journal of Turfgrass Science
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• v.20 no.2
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• pp.157-165
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• 2006

This study was initiated to investigate herbicidal selectivity margin with annual bluegrass and bentgrass according to growth stages through herbicidal spectrum of bispyribac-sodium and therefore to examine application possibility to prevent annual bluegrass selectively. The herbicidal efncacy by pre-emergence application was generally low. But a high herbicidal efficacy was observed over 90% for Shehpherd's purse. Foliar treatment resulted in a higher herbicidal efficacy in all tested plants except dallisgrass, lovegrass, curled dock and bentgrass as compared with pre-emergence application. We found bispyribac-sodium could be used as a selective weeding chemical between annual bluegrass and bentgrass. In regard to dose-responses to the growth stage, annual bluegrass was more susceptible to bispyribac-sodium than bentgrass for the same dosage. Particularly, bispyribac-sodium application in inflorescence emergence stage showed a greater herbicidal selectivity margin of 6.8 times with annual bluegrass over creeping bentgrass after 28 days from the application. These data demonstrated that annual bluegrass was more sensitive to bispyribac-sodium over creeping bentgrass.

• Journal of Plant Biotechnology
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• v.34 no.1
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• pp.61-68
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• 2007

To develop rice (Oryza sativa L.) cultivars to be planted on salt-affected sites, cell lines with enhanced proline content and resistance to growth inhibition by Azetidine-2-carboxylic acid (AZCA), a proline analogue, were screened out among calli irradiated with gamma ray of 50, 70, 90, and 120 Gy. The calli had been derived from embryo culture of the cultivar Donganbyeo. Selected AZCA resistant lines that had high proline accumulation were used as sources for selection of NaCl resistant lines. To determine an optimum concentration for selection of NaCl resistant lines, Donganbyeo seeds were initially cultured on the media containing various NaCl concentrations (0 to 2.5%) for 40 days, and 1.5% NaCl concentration was determined as the optimum concentration. One hundred sixteen salt-tolerant (ST) lines were selected from bulked 20,000 seeds of the AZCA resistant $M_{3}$ seeds in the medium containing 1.5% NaCl. The putative 33 lines ($M_{4}$ generation) considered with salt-tolerance were further analyzed for salt tolerance, amino acid and ion contents, and expression patterns of the salt tolerance-related genes. Out of the 33 lines, 7 lines were confirmed to have superior salt tolerance. Based on growth comparison of the entries, the selected mutant lines exhibited greater shoot length with average 1.5 times, root length with 1.3 times, root numbers with 1.1 times, and fresh weight with 1.5 times than control. Proline contents were increased maximum 20%, 100% and 20% in the leaf, seed and callus, respectively, of the selected lines. Compared to control, amino acid contents of the mutants were 24 to 29%, 49 to 143%, 32 to 60% higher in the leaf, seed and callus, respectively. The ratio of $Na^{+}/K^{+}$ for most of the ST-lines were lower than that of control, ranging from 1.0 to 3.8 for the leaf and 11.5 to 28.5 for the root, while the control had 3.5 and 32.9 in the leaf and root, respectively. The transcription patterns for the P5CS and NHXI genes observed by RT-PCR analysis indicated that these genes were actively expressed under salt stress. The selected mutants will be useful for the development of rice cultivar resistant to salt stress.