• Journal of Life Science
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• v.18 no.2
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• pp.206-212
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• 2008

The quorum sensing (QS) regulatory network has been the subject of extensive studies during recent years and has also attracted a lot of attention because it both positively and negatively regulates various putative virulence factors, although initially considered to be a specialized system of Vibrio fischeri and related species. In this study, to identify the novel materials which inhibit QS system of microorganisms, extracts of eighteen natural products were tested by bioassay using N-(3-oxohexanoyl)-$_L$-homoserine lactone and N-(3-oxooctanoyl)-$_L$-homoserine lactone synthesized in this experiment and an Agrobacterium tumefaciens NT1 biosensor strain containing a traI::lacZ fusion. The result indicated that the extracts of cabbage, leek, and onion exhibited the QS inhibition activity. Thus, materials contained in the extracts were isolated via recycling preparative HPLC and were purified via a JAIGEL-LS255 column. The common fraction corresponding to a peak of the 83 min point of them quenched the quorum sensing of A. tumefaciens NT1 biosensor strain in ABMM containing X-gal and was designated quorum sensing inhibitor-83 min (QSI-83). The QSI-83 exhibited the heat stability and did not inhibit the growth of A. tumefaciens NTl. Furthermore, thin layer chromatography (TLC) results suggested that these novel materials may be antagonists of N-acyl homoserine lactone or may inhibit the QS autoinducer synthesis by Pseudomonas syringae pv. tabaci.

• Journal of the Korean earth science society
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• v.25 no.6
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• pp.443-473
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• 2004

In northern Gohung granitic gneiss, porphyroblastic gneiss and migmatitic gneiss are widely distributed. Gneisses were plotted in granodiorite domain on an lUGS silica-alkali diagram. The amounts of trace elements (Li, Zn, Sc, Sr, Ni, V Y etc.) vs. $SiO_2$, somewhat decreased. Plagioclase showed a wide compositional range ($An_{32-48}$). $X_{alm}$ and $X_{sps}$ were higher in garnet rim and $X_{pyp}$ in garnet core. The rocks in the study area were formed from S and I-type magmas which generated from syn-collision and the late to post-orogenic tectonic environment. Metamorphic P-T conditions u·ere low to medium pressure, high temperature (803-913$^{\circ}C$, 6.1-7.3 kb) and overprinted by retrograde metamorphism (570-726$^{\circ}C$, 2.2-5.1 kb) and chloritization.

• Journal of the Korean earth science society
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• v.38 no.7
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• pp.561-569
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• 2017

Fault plane solutions of the Iksan earthquake ($M_L=3.85$) and two aftershocks were obtained using the FOCMEC (FOCal MEChanism determination) program. The main event showed the characteristic of strike slip faulting with reverse component. It has the fault planes with NE-SW or NW-SE direction. This is similar to the fault characteristics of earthquake pattern in the inland area of the Korean Peninsula. In order to detect micro-earthquake events, continuous seismic waveform data of the thirteen seismic stations within a radius of 100km from epicenter were analyzed by PQLII program (PASSCAL, 2017) for the period from December 15, 2015 to January 22, 2016. The epicenters of nineteen micro-events were newly determined by Hypoinverse-2000 program. They are not concentrated along some lineaments or fault lines. The intensity of the Iksan earthquake was obtained by estimating the telephone inquiries, the degree of ground shaking or damage all around the southern peninsula. The instrumental intensity was also obtained using PGA (Peak Ground Acceleration) records. As a result, the maximum MM intensity was estimated to be V near the epicenter.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.11
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• pp.1731-1736
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• 2014

The quality characteristics, enzyme activity, and antioxidative activity of fermented wild grass juices were investigated during fermentation and ripening for 6 months. Fermented wild grass juice was prepared from wild grasses (Oenothera biennis, Portulaca oleracea, and Rhus verniciflua) and sugar. Wild grasses and sugar mixed at the same ratio (1:1, w/w) and ripened at $20^{\circ}C$ for 3 months after fermentation for 3 months at $20^{\circ}C$. The $^{\circ}Bx$ of all fermented wild grass juices (FWGJ) decreased during fermentation. The pH of all FWGJ decreased gradually during fermentation and did not show any significant difference during ripening. Viscosity of FWGJ increased during fermentation but decreased during ripening periods in all tested samples. Total viable cell of FWGJ decreased after fermentation for 1 month, whereas lactic acid bacteria were not detected during fermentation. Enzyme activity was lower than 1 unit during fermentation and ripening period in all tested FWGJ samples. Enzyme activity of commercial FWGJ (Acanthopanax sessiliflorum, Oenanthe javanica, Plantago asiatica L., Platycodon grandiflorum, Orostachys japonicus A.) showed lower activity of 1 unit following invertase, cellulase, and amylase activity.

• Journal of Mushroom
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• v.8 no.4
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• pp.142-149
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• 2010

This study was conducted to investigate the physiological activities of the ethanol extracts from 10 different strains of Pholiota nameko. In addition, the ${\beta}$-glucan and polyphenol contents from these strains were also measured. Total polyphenol contents from all the strains were more than 40 mg% with the highest content of $61.50{\pm}0.59$ mg% and ${\beta}$-glucan contents were 30% with the highest content of $37.20{\pm}1.12%$. The highest inhibitory activities on ${\alpha}$-amyloglucosidase activity and nitric oxide production were $13.78{\pm}0.56%$ and $56.59{\pm}7.11%$, respectively. However, ethanol extracts from all the strains have little effects on DPPH radical and nitrite scavenging rates and the activity of angiotensin I converting enzyme. The cytotoxic activity of ethanol extracts from all the strains on A549 cell was shown upto 30% with the highest effect of $47.96{\pm}8.46%$ treated at 1 mg/mL concentration.

• Journal of Mushroom
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• v.15 no.2
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• pp.73-77
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• 2017

In Korea, oyster mushroom is one of the commonly cultivated mushrooms. In 2013, the cultivation areas and products of oyster mushrooms were 60,039 M/T and 201 ha, respectively. Many species of oyster mushrooms are cultivated in various countries. These include Pleurotus ostreatus, P. florida, P. sajor-caju, P. eryngii, P. citrinopileatus, P. salmoneostramineus and P. cystidiosus. P. citrinopileatus is a yellow oyster mushroom famous for its health benefits such as anti-cancer and anti-oxidant effects. Therefore, a cultivar P. citrinopileatus 'Jangdari' was developed to improve yield and the ability to grow well at lower temperatures. Two parent strains 'Gumbit (KMCC02150)' and 'KMCC02145' were selected based on their morphological characteristics. 'Jangdari' was developed by the method of Mon-Mon crossing between monokaryons derived from 'Gumbit' and 'KMCC02145', and finally selected through continuous cultivation tests. The optimum temperature for mycelial growth was $30^{\circ}C$. The cultivar could grow well at high temperatures, especially $16{\sim}24^{\circ}C$. Fruiting body production per bottle (850 mL) was about 90.0 g. Stipe length and thickness of 'Jangdari' were similar to those of 'Gumbit'. 'Jangdari' was more resistant to low temperature than 'Gumbit', and thus it could be cultivated with oyster mushrooms (P. ostreatus). In addition, while cultivating 'Jangdari', it is not required to scrape out the upper side of bottle's sawdust medium; hence, its cultivation is expected to save energy and time.

• Korean Journal of Environmental Agriculture
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• v.24 no.4
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• pp.398-403
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• 2005

To establish law-put fertilization technique and increase of fertilization efficiency during cultivation of plastic film mulching for plastic the improvement of soil properties, nutrition efficiency and yield by banded subsoil fertilization (BSF) using band spoty applicator was conducted at radish (Raphanus sativus L.) field in Honan Agricultural Research Institute from 1997 to 1998 for 2 years. These results were as follows. T-N, available $P_2O_5$ exchangeable Ca and K contents of soil were increased those of before experiment especially in BSF treatment. Also, the content of soil $NO_3-N$ was higher in BSF as fertilization amount is increasing than in CF (conventional fertilization). Uptake amounts of nitrogen fertilized were high in BSF during overall the growth period of plant and N utilization was high by $21.9{\sim}30.4%$ in BSF compared to in CF. The rate of fertilizer loss by rainfall was largely reduced, because all fertilizer applied was putted around the root zone. The total yields of fresh radish BSF treatments were more increased $13{\sim}37%$ than that of CF treatment.

• Korean Journal of Ecology and Environment
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• v.52 no.4
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• pp.333-339
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• 2019

The Red swamp crawfish Procambarus clarkii is native to the southern United States and inhibits all over the world including the United States, Asia, Africa and Europe. In Europe, it is known to disrupt ecosystems such as competition with native crayfish. In this study, habitats of red swamp crawfish were identified in Jiseok stream (15.5 km section) and Daecho stream (6.1 km section) of Youngsan river. A total 33 red swamp crawfish were captured. A female captured in Jiseok stream carried 215 newly hatched red swamp crawfish in her the burrow. As a result of the analysis of the habitat environment, the water temperature was ranged of 2.4~32.8℃, conductivity was 53.4~502.3 μS cm^-1 and DO was 0.74~22.64 mg L^-1. As a result of measuring HOBO, the temperature ranged from -9~48.1℃, showing a change of 57.1℃ throughout the year. The variation of the water temperature throughout the year from 2.9~33.9℃ was found to be 31℃. Red swamp crawfish have a high adaptability and a wide range of environmental resistance, and report a sharp increase in newly invaded areas, negatively affecting indigenous organisms. In addition, it can be used as a medium for the spread of diseases and parasites, so prompt investigation and research should be carried out.

• Korean Journal of Materials Research
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• v.2 no.1
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• pp.65-75
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• 1992

0.4wt%C steel added with V and/or Nb were forged and followed by air cooling. The structure-property relationships were examined and multiple regression analysis was conducted to quantify the magnitudes of effects of microalloying elements on the properties of the steels. All material's tensile strength are greater than $70kg/\textrm{mm}^2$, so they are equal to or superior to Q/T material's(S45C). Their impact energies are less than 40J, so they are 50% of Q/T material's. Increasing the content of V from 0.10 to 0.15 wt% had brought improvement in UTS about 20% but with some sacrifice of impact energy. These were the results from the precipitation strengthening by fine dispersion of VC in ferrite, increment of pearlite volume fraction and decrement of pearlite interlamellar spacings. However, increasing the content of Nb from 0.05 to 0.l0wt % slightly improved UTS and impact energy. NbC precipitates were more effective in suppression of austenite grain coarsening than VC precipitates. Combined additions of V+Nb were more effective to bring impact toughness than sole addition. Optimum combination of strength and toughness was accomplished wish 0.4C-1. 19Mn-0.05S-0.12V-0.07Nb steel.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.11
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• pp.1705-1709
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• 2010

Peppers (Capsicum annuum L.) are a rich source of phytochemicals including polyphenolics, flavonoids, capsaicinoids and ascorbic acid. Capsaicinoids are a group of 12 or more related alkaloids responsible for the pungent sensation in the fruits of the genus Capsicum. Ascorbic acid is another functional and nutritional constituent of peppers. In this study, the contents of two major capsaicinoids (capsaicin and dihydrocapsaicin) and ascorbic acid in 131 pepper breeding lines were quantified by HPLC. In 131 pepper breeding lines, capsaicin and dihydrocapsaicin contents were in the range of 0.0 to 219.6 and 0.0 to 110.8 mg/100 g, respectively. The breeding lines with higher capsaicin content contained higher dihydrocapsaicin content as well. Ascorbic acid contents were 264.9 to 1695.5 mg/100 g for the 131 pepper breeding lines. The analytical method validation parameters including accuracy, repeatability, and reproducibility were calculated to ensure the method's validity. This study provides basic information to plant breeders and biotechnologists who are planning to breed genotypes with high content of phytochemicals.