• Journal of Ginseng Research
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• v.40 no.2
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• pp.97-104
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• 2016

Background: Rhizobacteria play an important role in plant defense and could be promising sources of biocontrol agents. This study aimed to screen antagonistic bacteria and develop a biocontrol system for root rot complex of Panax notoginseng. Methods: Pure-culture methods were used to isolate bacteria from the rhizosphere soil of notoginseng plants. The identification of isolates was based on the analysis of 16S ribosomal RNA (rRNA) sequences. Results: A total of 279 bacteria were obtained from rhizosphere soils of healthy and root-rot notoginseng plants, and uncultivated soil. Among all the isolates, 88 showed antagonistic activity to at least one of three phytopathogenic fungi, Fusarium oxysporum, Fusarium solani, and Phoma herbarum mainly causing root rot disease of P. notoginseng. Based on the 16S rRNA sequencing, the antagonistic bacteria were characterized into four clusters, Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetesi. The genus Bacillus was the most frequently isolated, and Bacillus siamensis (Hs02), Bacillus atrophaeus (Hs09) showed strong antagonistic activity to the three pathogens. The distribution pattern differed in soil types, genera Achromobacter, Acidovorax, Brevibacterium, Brevundimonas, Flavimonas, and Streptomyces were only found in rhizosphere of healthy plants, while Delftia, Leclercia, Brevibacillus, Microbacterium, Pantoea, Rhizobium, and Stenotrophomonas only exist in soil of diseased plant, and Acinetobacter only exist in uncultivated soil. Conclusion: The results suggest that diverse bacteria exist in the P. notoginseng rhizosphere soil, with differences in community in the same field, and antagonistic isolates may be good potential biological control agent for the notoginseng root-rot diseases caused by F. oxysporum, Fusarium solani, and Panax herbarum.

• Journal of Ginseng Research
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• v.32 no.4
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• pp.332-336
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• 2008

Red ginseng is classified according to outer form and the quality of internal tissue, and red ginseng below third grade can't be sold. Also there are many differences in price according to grade. So if inferior Red ginseng is sold, economic loss and claim take place. This research is done conducted to investigate the possibility of the non-destruction internal tissue investigation of red ginseng. It is observed and compared that MR image after getting MR image agrees with real cutting side in 10-13% water content of red ginseng. The MR image can be obtained to see the internal section of red ginseng with equal condition of time, temperature and slice thickness in spin echo pulse sequence. The MR signal of red ginseng is very weak, because it contains low water density. So it takes about 30 minutes with the measurement of single point image (SPI). But the suitable time to distinguish internal tissues is about 9 seconds in TE (Echo Time) 2.23 ms, TR (Repetition Time) 150ms. The image to discriminate internal tissues in 9 seconds can be obtained when slice thickness is 10 mm with changes of 3, 5, 10 mm. The image obtained after 30 minutes' boiling of 55 degrees has clearer image than that of normal temperature. It is thought that MR signal is stronger through active motion of water particles as temperature increases. With this method MR image of red ginseng can be obtained and characteristics of internal tissues can be observed in such a short time.

• The Journal of Engineering Research
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• v.3 no.1
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• pp.181-187
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• 1998

Hydroxyapatite was used as implant materials, because it has a good biocompatibility and is similar to human bone. However it is not expected to have a high strength as implant materials because of a low fracture strength after sintering of HAp. Alumina ($\alpha$-alumina) shows a stable chemical properties and high strength in physiological environments. Thus it was tried to use a HAp coatings on Alumina substrate as implant materials. In this study, HAp was coated on Alumina substrate by lon Beam Assisted Deposition(IBAD). Then Ag was impregnated on HAp coating layer, which showed antimicrobial effects. To carry out the ion exchange of $Ag^+$ with $Ca^{2+}$ in HAp on the surface, HAp coated alumina substrate was immersed in 20ppm, 100ppm $AgNO_3$ solution at room temperature for 48 hours. Antimicrobial test was studied by using bacteria, which normally caused periprosthetic infections. The follwing bacteria was used in antimicrobial test. Escherichia coli, Pseudomonas aeruginosa (gram negative) and staphylococcus epidermidis (gram positive). Ag impregnated HAp shows very good antimicrobial effects against these bacteria. The surface structure of sample, which was treated in $AgNO_3$ solution was studied by SEM, XRD. Ag release curve was studied in Simulated Body Fluid (SBF) solution.

• The Journal of the Petrological Society of Korea
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• v.10 no.3
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• pp.148-156
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• 2001

We report $^{230}Th/^{234}U$ disequilibrium ages of fracture-filling carbonate veins from the Ipsil and Janghangri fault zones, Gyeongju, Korea by multiple collector inductively coupled plasma mass spectrometry. The U and Th fraction was extracted from totally dissolved samples by rapid and convenient coprecipitation and ion exchange chemistry. The recovery was around 80% for Th and 70% for U. The $^{234}U/^{238}U,\;^{230}Th/^{232}Th$ ratios were analysed for this preconcentrated fraction and the U/Th ratio was directly analysed for untreated sample solution. The $^{234}U-^{230}Th$ system is in secular equilibrium for the Ipsil carbonate samples, supporting previously reported ESR ages. The detrital-corrected $^{230}Th/^{234}U$ age of the Janghangri carbonate samples is $48\pm$41 ka, which constrains the minimum age of the fracture zone.

• The Journal of the Petrological Society of Korea
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• v.19 no.3
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• pp.181-197
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• 2010

This study is for finding a geoscientific factor for clarifying the source soil of the ancient earthenware finding. The used samples were the earthenware, soil and rocks, which were collected at the Gyeongju, Gyeongsan and Haman area. The chemical and mineralogical study for the samples were carried out for understanding the change of mineralogical and chemical composition among them. The mineralogical compositions of the earthenware are different from those of the soils from the surrounding area, which suggests that the mineralogical approach for clarifying the source soil of the earthenware should be difficult. Major element compositions of the earthenware also are different from those of the surrounding soils, which suggests that the comparison of the chemical composition using the major elements might be difficult for deducing the source soil of the earthenware. However, PAAS-normalized rare earth element (REE) patterns and Nd model ages among the rock, soils and earthenware from the same sampling sites show similar characteristics one another compared to those of the major element compositions. Nd-Sr isotopic systematics among the earthenware, soils and rocks also show a close relationship. Our results suggest that REE and Nd-Sr isotope geochemistry might be more useful than the other geochemical technique in clarifying the source soils of the ancient earthenware.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.99-103
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• 2005

Nitrogen content of liquid manures varies from $3g\;kg^{-1}\;to\;7g\;kg^{-1}$ according to the collecting seasons. The application effects of liquid manure on the yield of rice are the best in LPM+LPM treatment, although the lodging of crops increased and the quality of rice is deteriorated. When application with LPM+CF treatment and CF+LPM treatment showed no difference in rice yield and quality, compared with CE+CF treatment. Therefore, use of liquid manure on farmland should be limited as once per year during cultivation duration and liquid manure is fully fermented during 6 months at least in order to decrease the damage of crops by application of unmatured liquid manure. Also, application amount of liquid manure should be carefully determined by considering the mineral (especially nitrogen) contents of liquid manure and the recommended fertilizer levels for various crops.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.356-356
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• 2017

A field experiment was performed to evaluate the effects of tillage systems and fertilizer management on yield and nutrient uptake in Soybean. The plant height, fresh weight and dry weight of conventional tillage were much higher those observed for no-tillage. Significant differences in plant height were observed under tillage practices combined with fertilizer treatment. However, the greatest plant height (128.47 cm) was observed in conventional tillage with chemical fertilizer, and the lowest (45.4 cm) was observed in the no-tillage with green manure treatment. The highest fresh weight (172.4 g) and dry weight (44.1 g) were observed from the no-tillage chemical treatment in the late flowering stage of soybean. The plant concentration of nitrate was higher (2.29%) in no-tillage with green manure than it was with chemical fertilization. However, nitrogen increased steadily in all treatments, and the highest quantity of total nitrogen (476.7 Kg/ha) was observed in no-tillage with green manure. The N content in the soil decreased gradually just after the vegetative stage. Tillage practices and additional fertilizer application had an adverse effect on the uptake of N, P and K in soybean seeds. The nitrogen concentration in seeds was found to be increased in the no-tillage with green manure treatment. The uptake of more nitrogen induced a better yield. Thus, the no-tillage with green manure treatment had the greatest yield, although no significant difference was observed among foliar-applications and additional fertilization. Additionally, the phosphorus and potassium concentrations in seeds remained the same between the conventional tillage and no-tillage treatments. The results obtained in this study indicate that no-tillage strategies with fertilizers may influence the growth characteristics and mineral uptake in soybean.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.127-127
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• 2017

Aluminum is the most abundant metallic element in the Earth's crust and considered as the most limiting factor for plant productivity in acidic soils. The inhibition of root growth is recognized as the primary effect of Al toxicity. Seeds of wheat cv. Keumkang (Korean cultivar) were germinated on petridish for 5 days and then transferred hydroponic apparatus which was treated with $0{\mu}M$ $AlCl_3$ (control), $100{\mu}M$ $AlCl_3$ and $150{\mu}M$ $AlCl_3$ for 5 days. The length of roots, shoots and fresh weight of wheat seedlings were decreased under aluminum stress. The concentrations of $K^+$, $Mg^{2+}$ and $Ac^{2+}$ were decreased whereas $Al^{3+}$ and $P_2O_5{^-}$ concentration was increased under aluminum stress. Using confocal microscopy, the fluorescence intensity of aluminum was increased with morin staining. In this study, a proteome analysis was performed to identify proteins, which is responsible to aluminum stress in wheat roots. In 10-day-old seedlings, proteins were extracted from roots and separated by 2-DE, stained by CBB. Using image analysis, a total of 47 differentially expressed protein spots were selected, whereas 19 protein spots were significantly up-regulated such as s-adenosylmethionine, oxalate oxidase, malate dehydrogenase, cysteine synthase, ascorbate peroxidase and 28 protein spots were significantly down-regulated such as heat shock protein 70, o-methytransferase 4, enolase, amylogenin by aluminum stress following protein spots analyzed by LTQ-FTICR mass spectrometry. The results provide the global picture of Al toxicity-induced alterations of protein profiles in wheat roots, and identify the Al toxicity-responsive proteins related to various biological processes that may provide some novel clues about plant Al tolerance.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.24-24
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• 2017

Heavy metals at toxic levels have the capability to interact with several vital cellular biomolecules such as nuclear proteins and DNA, leading to oxidative stress in plants. The present study was performed to explore the metal tolerance mechanism in Sorghum seedling. Morpho-physiological and metal ions uptake changes were observed prominently in the seedlings when the plants were subjected to different concentrations of $CuSO_4$ and $CdCl_2$. The observed morphological changes revealed that the plants treated with Cu and Cd displayed dramatically altered shoot lengths, fresh weights, and relative water content. In addition, the concentration of Cu and Cd was markedly increased by treatment with Cu and Cd, and the amount of interacting ions taken up by the shoots and roots was significantly and directly correlated with the applied level of Cu and Cd. Using the 2-DE method, a total of 24 and 21 differentially expressed protein spots from sorghum leaves and roots respectively, 33 protein spots from sorghum leaves under Cd stress were analyzed using MALDI-TOF/TOF MS. However, the over-expression of GAPDH plays a significant role in assisting Sorghum bicolor to attenuate the adverse effects of oxidative stress caused by Cu, and the proteins involved in resistance to stress helped the sorghum plants to tolerate high levels of Cu. Significant changes were absorbed in the levels of proteins known to be involved in carbohydrate metabolism, transcriptional regulation, translation and stress responses. In addition, the up-regulation of glutathione S-transferase and cytochrome P450 may play a significant role in Cd-related toxicity and stress responses. The results obtained from the present study may provide insights into the tolerance mechanism of seedling leaves and roots in Sorghum under heavy metal stress.

• Economic and Environmental Geology
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• v.30 no.1
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• pp.61-65
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• 1997

Cadmium occurs as a minor element in sphalerite ((Zn, Fe)S) from the Boseong-Jangheung gold-silver mine district. We analyzed the abundance of cadmium in sphalerite using an electron probe micro analyzer (EPMA) and discussed the natural sources of cadmium in terms of bedrock geochemistry, in order to preliminarily reconnoiter the potential cadmium contamination in mine districts. Cadmium contents of sphalerites from the Au-Ag mines (Bodeok, Mundeok, Jeonbo, Boknae, Keumsan) in the Boseong-Jangheung district are considerably high, compared with cadmium contents of sphalerites (average = 0.5 wt.% Cd, maximum = 4.4 wt.% Cd) in the world. Sphalerites from the Keumsan mine (average = 9.49 wt.% Cd, maximum=11.22 wt. Cd) are highly enriched in cadmium. Our data suggest that the Boseong-Jangheung area is an important potential site of cadmium contamination in Korea. Based on bedrock geochemistry, natural causes of cadmium enrichment in sphalerite from the mine district are thought to be the mixing of cadmium leached from organic-rich, metasedimentary rocks (including coal) and/or black shales. From this study, we propose that the pinpointing of potential sites of pollution by toxic heavy metals can be done effectively through detailed reconnaisance study on mineralogical compositions of ore minerals such as sphalerite from the mine area.