• Korean Journal of Soil Science and Fertilizer
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• v.38 no.1
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• pp.38-44
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• 2005

In addition to the variation in nitrate accumulation of vegetables due to environmental conditions, there is also a distinct genetic variation. The variation of nitrate accumulation in some cultivars of lettuce and spinach commonly cultivated in Korea was investigated. Ten cultivars for both lettuce and spinach were grown in plastic containers filled with a 1:1 mixture of perlite and vermiculite with application of Hoagland No. 2 nutrient solution of high nitrate content (17.3 mM N) in a greenhouse condition. Plants were harvested four weeks after transplanting four-leaf stage seedlings. Plant growth was measured by fresh and dry matter of shoot, and contents of nitrate and other inorganic ions and organic solutes including sugar, amino acids and organic acids were measured. Large and significant genotypical variations in the nitrate content of the plants were found for both lettuce and spinach, and high negative correlations between nitrate content and fresh or dry weight were found in lettuce and spinach. Variation in nitrate accumulation of lettuce and spinach cultivars was not directly related to the differences in contents of organic and inorganic solutes, and this result indicates that photosynthesis and osmotic regulation are not directly related with the nitrate accumulation. Considering the correlations between nitrate content and plant growth of this study, it can be simply suggested that different cultivars of lettuce and spinach have their own inherited growth and physiological characteristics and also optimum nitrogen level required for the growth. Therefore when available nitrogen in root media is higher than the optimum level required for the inherited growth potential, some of the excess nitrate supplied can be accumulated in plants.

• The Korean Journal of Pesticide Science
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• v.18 no.2
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• pp.88-94
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• 2014

Among pre-harvest environmental factors, increasing attention has been paid to the effects of chemical and microbiological factors on fresh produce. The occurrence and prevalence of these factors have been usually studied with regard to the final products at the post-harvesting stage and/or when they are sold in the market. However, the origin and routes of transmission of both factors remain to be clarified. In the present study, we examined the contamination levels of food-borne pathogens and chemical factors such as pesticide residues and heavy metals in 83 and 43 samples, respectively, including various soil, water, and fertilizer samples, as well as post-harvested and processed samples. Among the organic farming samples, only one pesticide, dimethomorph, was detected in the soil sample, however no pesticides were observed from any other samples in organic farming system. Thus, it was thought that might be contaminated from conventional farm land in the vicinity. Whereas many pesticide residues were detected in conventional farming systems such as soil, fertilizer, water, and fresh produce as expected. Furthermore, heavy metals detected from all tested samples did not shown contamination levels higher than the standard limit. We comparatively assessed the levels of contamination by food-borne pathogens on the samples from organic and conventional farming systems, and found aerobic bacteria at approximately 7 log CFU/g, with no significant differences observed between the two systems. Coliforms were present at lower levels than aerobic bacteria. No human pathogens were present among the coliforms detected, indicating that these bacteria are saprophytes without the ability to cause food-borne illnesses. In contrast, among the high-risk food-borne pathogens, only sporadic cells of Bacillus cereus were found on samples of organic farming system. These data extend previous findings that the most prevalent food-borne pathogen is B. cereus and demonstrate that it spreads to whole living plants via soil.

• Clinical and Experimental Reproductive Medicine
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• v.37 no.2
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• pp.143-151
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• 2010

Objective: The aim of this study was to compare day 3 embryo transfer (D3ET) with day 5 ET (D5ET) in fresh in vitro fertilization (IVF) cycle on pregnancy outcomes. Methods: We conducted a retrospective matched case control study that included 90 women with D3ET and 90 women with D5ET from January 2007 to June 2009. Subjects were matched for reproductive profiles and IVF cycle characteristics. Two good quality embryos were transferred in both groups. Pregnancy rates (PR), implantation rate, and multiple PR were compared. Results: Demographics, stimulation parameters and embryological data were comparable in both groups. Main pregnancy outcomes with D3ET and D5ET groups were not statistically different: implantation rate (39.4% vs. 32.8%), positive PR (57.8% vs. 46.7%), clinical PR (53.3% vs. 45.6%), ongoing PR (50.0% vs. 42.2%), respectively. Both groups showed high multiple PR (37.5% vs. 34.1). Conclusion: D5ET may not be beneficial and necessary in comparison with D3ET on pregnancy outcomes, and elective single ET should be considered to decrease multiple pregnancies in women with favorable conditions and good quality embryos undergoing IVF.

• Journal of Mushroom
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• v.13 no.3
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• pp.163-169
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• 2015

The in vitro experiment was conducted to ensure the supplemental level of spent Flammulina velutipes mushroom substrates (SMS) as an energy source in manufacturing of whole crop sorghum silage. Sorghum harvested at heading stage was ensiled with spent mushroom substrates of 20% (S-20), 40% (S-40) and 60% (S-60) as fresh matter basis for 6 week. The experiment was conducted by 3, 6, 9, 12, 24, 48 hrs of incubation time with 3 replications. The silages were evaluated fermentation characteristics and dry matter digestibility (DMD) in vitro. The pH of in vitro solution was inclined to decrease with elapsing the incubation time, and that of the S-20 was significantly (P<0.05) lower than the other treatment at 48 hr of incubation. Gas production was greater (P<0.05) in the S-20 than the other treatments at 6 and 12 hrs of incubation. The microbial growth in vitro was inclined to decrease following 24 hr of incubation, and thereafter sustained the similar levels. In vitro dry matter digestibility (IVDMD) was lowered by increasing the supplemental level of spent mushroom substrate, and was a low level in the S-60 throughout whole incubation time. Although the IVDMD for S-40 was steadily increased from 9 hr of incubation and reached to similar level with the S-20 at 48 hour of incubation, however SMS for whole crop sorghum silage fermentation might as well add about 20 to 30% in fresh matter basis when considering DMD.

• Horticultural Science & Technology
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• v.32 no.4
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• pp.484-492
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• 2014

We quantified the effects of the composition and concentration of fertilizer solutions on the growth and nutrient uptake of 'Maehyang' strawberry at the vegetative growth stage. Acid fertilizer (AF), neutral fertilizer (NF), and basic fertilizer (BF) with concentrations of 100 or $200mg{\cdot}L^{-1}$ based on N, were formulated and applied during the 100 days after transplanting, at which point crop growth and tissue nutrient contents were analyzed. The soil solutions were sampled every two weeks to measure the pH, EC and nutrient concentrations. BF was a more effective fertilizer compared to AF and NF for growth of 'Maehyang' strawberry when fertilizer concentrations were controlled to $100mg{\cdot}L^{-1}$. By contrast, the fresh and dry weights were greatest in the NF treatment when fertilizer concentrations were controlled to $200mg{\cdot}L^{-1}$. The tissue contents of N, P, and Na were 2.20, 0.51 and 0.10%, respectively, in the NF 200 treatment, and these were the highest among all treatments tested. The highest contents of K, Ca and Mg were 2.60% in AF 200, 0.95% in BF 200 and 0.45% in BF 100, respectively. During the fertilization period, the highest and lowest pHs were 6.13 in BF 100 and 4.92 in AF 200. The lowest EC was $1.376dS{\cdot}m^{-1}$ in BF 100 and the highest was $4.936dS{\cdot}m^{-1}$ in NF 200 treatments. The highest $NH_4{^+}$ concentrations in the soil solution occurred during the AF 200 treatment, followed by those with NF 200 and AF 100. When fertilizer concentrations were equal, AF treatment gave rise to the highest $Ca^{+2}$ and $Mg^{+2}$ concentrations, followed by NF and BF, until day 84 of fertilization. The BF treatments had the highest $NO_3{^-}$ concentrations followed by NF and AF. The trends for $PO_4^{-3}$ concentrations were similar in all fertilizer treatments when the fertilizer concentrations were equal. The above results indicate that neutral and basic fertilizers were most effective to promote 'Maehyang' strawberry growth when fertilizer solutions were controlled to low or high concentrations, respectively. These findings are useful for planning fertilization programs for vegetative propagation of 'Maehyang' strawberry.

• Horticultural Science & Technology
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• v.30 no.4
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• pp.442-448
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• 2012

Many outbreaks of food-borne illnesses have been associated with the consumption of fresh vegetables and fruits contaminated with food-borne pathogens. Contaminated medium, manure and irrigation water are probable vehicles for the pathogen in many outbreaks. The aim of this study was to determine the potential transfer of Escherichia coli and Bacillus cereus from medium and soil fertilized with contaminated compost or irrigation with contaminated water to the edible parts of lettuce. Moreover, survivals of the two pathogens on lettuce contaminated medium, soil and irrigation water were estimated. Lettuce seeds were planted in medium contaminated with 7.5 log colony forming unit (CFU)/g of E. coli and B. cereus. Seedlings grown in the contaminated medium were transplanted in soil fertilized with contaminated pig manure compost or uncontaminated soil. Contaminated irrigation water with E. coli and B. cereus at 8.0 log CFU/mL was applied only once on the plant by sprinkle irrigation and surface irrigation. Although E. coli and B. cereus in medium and sprouted lettuce after planting seeds were reduced as time passed, these pathogens survived in seedling raising stage for extended periods. The numbers of E. coli and B. cereus in lettuce grown on contaminated soil were detected over 4.0 log CFU/g for 21 days. The numbers of E. coli and B. cereus in lettuce applied by sprinkle irrigation were higher than those of surface irrigation by 5.0 log CFU/g. Our results indicated that contaminated medium, soil and irrigation water can play an important role in the presence of food-borne pathogens on vegetables.

• The Journal of the Petrological Society of Korea
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• v.13 no.4
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• pp.224-237
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• 2004

The anorthositic rocks of the study area are divided into the northern Sancheong and southern Hadong anorthositic rocks depending on the different distribution patterns and lithologies. In order to evaluate the characteristics of the hydrothermal systems developed in the study area, oxygen and hydrogen isotopic compositions of the anorthositic rocks were measured. Oxygen isotopic values of the plagioclase exhibit an interesting spatial distribution. Plagioclase collected from the Sancheong anorthositic rocks in the northern part tends to have a relatively restricted range of $\delta$$^{18/0}$ values between 7.3 and 8.8$\textperthousand$, which are heavier than 'normal' $\delta$$^{18/O}$ value (6-6.5$\textperthousand$) typical for plagioclase of the fresh mantle-derived anorthosite, whereas plagioclase from the southern part is characterized by a wide range of $\delta$$^{18/O}$ values between -4.4 and 8.2$\textperthousand$ and much lighter values than 'normal' value for plagioclase of the fresh mantle-derived anorthosite. Plagioclase from the middle part has $\delta$$^{18/O}$ values heavier than the plagioclase from the southern part, but lighter than that from the northern part. The spatial distribution of $\delta$$^{18/O}$ values suggests that the decoupled hydrothermal flow systems might have been developed in the study area. Meteoric water dominated in the hydrothermal flow systems developed in the southern area, whereas magmatic fluid dominated in the northern area. The relationship between water content and hydrogen isotopic composition of anorthosites shows a positive correlation. The positive correlation indicates that fluids exsolved from magma during magmatic differentiation caused deuteric alteration of anorthositic rocks involving replacement of pyroxenes to amphiboles. After the deuteric alteration, hydrothermal system developed by meteoric water dominated the southern area, and erased record of the hydrothermal system developed by magmatic fluid at earlier stage. However, the development of meteoric hydrothermal system has been limited in the southern area only, and could not affect the Sancheong anorthositic rocks in the northern area. The abundant occurrences of secondary alteration minerals such as sericite, calcite, and chlorite in the southern Hadong anorthosite relative to the northern Sancheong anorthositc seem to be related to the overlapping of two distinct hydrothermal systems in the southern area.

• Journal of Fisheries and Marine Sciences Education
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• v.18 no.3
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• pp.209-217
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• 2006

In this study, chemical compositions of Helice tridens tientsinensis(Htt, sea crab) and changes of chemical compositions in fermented sea crab tested according to different storage days(10, 16, 20, 25, 29, 55, 61, 67). The average amount of chemical compositions in raw Htt, it contains 77.12% of moisture, 1.96% of ash, 18.93% of crude protein, 0.26% of crude lipid. During storage time the amount of moisture and crude protein decreased, but crude lipid and ash increased. The amount of volatile basic nitrogen in Htt showed 6.56 mg/100g. The fermented sea crab in brine stored at the temperature of $5^{\circ}C$ showed 23.72 mg/100g of freshness even after 55 days. It showed first stage of decomposition(31.69 mg/100g) after 61 days. it is most efficient to store fermented sea crab at a low temperature. The amount of free amino acid composition in fresh Htt, was measured as follow ;arginine(1140.88 mg/100g), alanine(311.26 mg/100g), prorine(214.63 mg/100g), serine(113.56 mg/100g), taurine(90.80 mg/100g). The amount of amino acid in fermented sea crab increased as the storage days increased. Fatty acid contents in fresh Htt showed the largest amount of erucic acid (27.39 area%) and pentadecenoic acid (19.44 area%), oleic acid (17.68 area%), palmitic acid (11.00 area%), stearic acid (6.89 area%), and elaidic acid (6.15 area%) in order. In fermented sea crab, a small change was noticed in quantity, but the obvious increased composions were palmitoleic and heneicosanoic acid etc.

• Horticultural Science & Technology
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• v.31 no.1
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• pp.65-71
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• 2013

This research was conducted to evaluate the influence of $NO_3{^-}:NH_4{^+}$ ratios in fertilizer solution on the vegetative growth and fruit yield of hot pepper (Capsicum annuum L.) through pot cultivation. The Hoaglad's solution was modified to contain various $NO_3{^-}:NH_4{^+}$ ratios such as 100:0 (A), 73:37 (B), 50:50 (C), 27:73 (D), 0:100 (E), and no nitrogen (F). Plants were transplanted into root substrates and the modified solutions were applied as plant needed in plastic house. There were no statistical significances among the treatments from A through D in the fresh and dry weights, and number of leaves 31 days after transplanting, but elevation of $NH_4{^+}$ ratios in the solution decreased the fresh fruit weight 62 days after transplanting with statistical differences. In the results of inorganic element analysis based on the dry weight of fully expanded mature leaves, N and P contents as well as micro cations such as Fe, Mn, Zn, and Cu increased as $NH_4{^+}$ ratios were elevated 62 days after transplanting. However, those of macro cations such as K, Ca, and Mg resulted in decreasing tendency. The elevation of $NH_4{^+}$ ratios in fertilizer solution resulted in the increase of EC and total N concentrations ($NO_3{^-}+NH_4{^+}$), but this decreased the pH as well as Ca and Mg concentrations in soil solution 62 days after transplanting. The K concentration in soil solution was the highest in the treatments of C and followed by D, B, E, and A. The above results indicate that the proper $NO_3{^-}:NH_4{^+}$ ratio in the nutrient solution is 73:27 (B) or 100:0 (A) and the B solution is proper for the vegetative growth and that of A is proper for reproductive growth stage.

• Journal of agriculture & life science
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• v.46 no.1
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• pp.91-103
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• 2012

The aim of this study was to develop a rapid and cheap bioassay of four lignans (schisandrin, schisandrin C, the gomisin A and gomisin N) isolated from Schizandra chinensis Baill on seed germination and seedling growth of the radish. Its structure was determined by analysis of MS and NMR spectroscopic data. Radish seeds immersed for 1 hr in the solutions of $10^{-5}M$, $10^{-6}M$ and $10^{-7}M$ of schisandrin, schisandrin C, gomisin A, and gomisin N, seed germination was observed with in 60 hr after all of the treatments. Also, the seeds were germinated faster compared to untreated controls. At early germination stage, 48 hr after the treatment of the lignans, the suppression of germination was observed from all treatments; the suppression due to schisandrin and gomisin A was the highest at the concentration of $10^{-6}M$. The level of suppression increased as the concentration increased in the treatment of schisandrin C and gomisin N. Percent germination of seed after 184 hr was increased 90% at all treatments. For the effects of lignan treatment on seedling growth in radish, the growth of hypocotyl was promoted by gomisin A and gomisin N at all concentrations. Root elongation was significantly promoted by schisandrin and gomisin N at $10^{-5}M$ and $10^{-6}M$, respectively. Fresh and dry weights of the seedlings were high at a low concentration of $10^{-7}M$, but significantly reduced by schisandrin C at a high concentration of $10^{-5}M$. The results of the germination activity and seedling growth of the lignans from S. chinensis suggest their potential use as natural growth regulators.