• Parasites, Hosts and Diseases
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• v.28 no.2
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• pp.71-78
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• 1990

To assess the role of cAMP on the growth and proliferation of Toxoplasma in HL-60 cells we tested the effect of exogenous cAMP and cAMP analogues to the co-culture system of Toxoplasma and HL-60 cells. cAMP, dbcAMP, and br-cAMP stimulated the growth of Texoplasma at a specific concentration, i.e., 100 mM, l00 mM, and 10-1 mM, respectively. There were differences in growth induction kinetics and in the rate of promotion. These results were further verified by treating the co-culture with adenylate cyclase activator, pNHppG, cAMP phosphodiesterase activators, imidasole and A23187, and cAMP phosphodiesterase inhibitors, IBMX, compound 48/80, and theophylline, separately. When the cytosolic cAMP levels increased by the reagents mentioned above, Toxoplasma in the cytoplasm of HL-60 cells stimulated to proliferate more rapidly with concentration-dependent modes compared to the control, and vice versa. It is suggested that some mechanisms are activated by the high levels of cAMP in the cytoplasm, which result in the stimulation of Toxoplasma proliferation.

• Korean Journal of Plant Tissue Culture
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• v.24 no.2
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• pp.119-124
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• 1997

Plantlets were regenerated from various explants (shoot tip, leaf blade, petiole and root segments) via organogenesis and/or somatic embryogenesis from Armoracia rusticana(Lam) Gaerth., Mey, et Scherb.. Shoot regeneration rate from callus was highest on the MS mediums supplemented with 0.5 ㎎/L IAA, 5.0㎎/L BA and 10.0㎎/L spermine. A Low frequency of regeneration occurred on hormone-free MS medium. Multiple shooks were regenerated at a pH of 4.0 to 8.0 on MS medium supplemented with 1.0 ㎎/L BA and 0.1 ㎎/L NAA. Polyamines promoted shoot- and root-formation by 2 to 4 times normal, Specific proteins associated with organogenesis were identified. Somatic embryogenesis occurred directly from the leaf blade, petiole and root segments cultured on MS medium with 2.0 ㎎/L BA and 2.0 ㎎/L BA and 2.0 ㎎/L NAA. Three types of regeneration in A, rusticana were clearly established, which could be applied to the study of morphogenesis and genetics at cell, tissue and organ levels.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.4
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• pp.247-255
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• 2003

A bacterium, KJA-118 showing a strong chitinase activity, was isolated and identified as Bacillus cereus. The strain produced maximum level of chitinase, when grown aerobically at $30^{\circ}C$ for 4 days in basal broth containing 1% colloidal chitin in the initial pH adjusted to 6.0. Among various carbon sources such as crab shell powder, chitin powder, colloidal chitin, and R. solani mycelium, maximum chitinase activity was found in culture broth supplemented with R. solani mycelium. When KJA-118 was incubated with R. solani, the cell wall of the fungus was found to be completely destroyed. SDS-PAGE and active staining results revealed that KJA-118 produced three isoforms of chitinase with molecular weights of 68 kDa, 47 kDa, and 37 kDa. When the suspension of KJA-118 was treated to cucumber seedlings, reducing rate of damping-off caused by R. solani was about 28.1%.

• Korean Journal of Ecology and Environment
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• v.39 no.1 s.115
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• pp.52-61
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• 2006

The aim of this study was to analyze the seasonal patterns of zooplankton community dynamics in the lower Nakdong River (Mulgum, RK; river kilometer; 27 km from the estuarine barrage), with a Self-Organizing Map (SOM) based on weekly sampled data collected over ten years(1994 ${\sim}$ 2003). It is well known that zooplankton groups had important role in the food web of freshwater ecosystems, however, less attention has been paid to this group compared with other community constituents. A non-linear patterning algorithm of the SOM was applied to discover the relationship among river environments and zooplankton community dynamics. Limnological variables (water temperature, dissolved oxygen, pH , Secchi transparency, turbidity, chlorophyll a, discharge, etc.) were taken into account to implement patterning seasonal changes of zooplankton community structures (consisting of rotifers, cladocerans and copepods). The trained SOM model allocated zooplankton on the map plane with limnological parameters. Three zooplankton groups had high similarities to one another in their changing seasonal patterns, Among the limnological variables, water temporature was highly related to the zooplankton community dynamics (especially for cladocerans). The SOM model illustrated the suppression of zooplankton due to the increased river discharge, particularly in summer. Chlorophyll a concentrations were separated from zooplankton data set on the map plane, which would intimate the herbivorous activity of dominant grazers. This study introduces the zooplankton dynamics associated with limnological parameters using a nonlinear method, and the information will be useful for managing the river ecosystem, with respect to the food web interactions.

• Journal of the Korea Concrete Institute
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• v.17 no.5 s.89
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• pp.811-818
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• 2005

It is well known that the fluidity and the fluidity loss of fresh concrete are affected by the kind of organic admixtures. Organic admixture can improve the properties of concrete. Sulfonated Naphthalene-Formaldehyde(SNF) Superplasticizer is used representatively, but has a problem in fluidity loss. In this study, we synthesized the Sulfonated Melamine-Formaldehyde(SMF) superplasticizer at the various synthetic conditions and compared the physical properties with SMF superplasticizer. SW superplasticizer is synthesized with four synthetic steps. Step 1 is hydroxymethylation, Step. 2 is Sulfonation, Step. 3 is Polymerization and Step. 4 is Stabilization. Synthesis of SMF superplasticizer depends on pH, temperature and reaction time. In this reaction, we changed the mole ratio of melamine to formaldehyde at 1:3, 1:4, and the amount of acid catalyst at Step. 3. After application of SMF superplasticizer and its mixture with SNF superplasticizer to cement pastes and mortars, we measured the physical properties of them at the different dosages(0.5, 1.0, 1.5 wt%) to cement. All samples including superplasticizer showed higher compressive strengths and slump, smaller pore size and porosity than CEM

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3731-3739
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• 2009

One-chambered sediment cells with a variety of anodic electrodes were tested for generation of electricity. Material used for anodes was iron, brass, zinc/iron, copper and graphite felt which was used for a common cathode. The estuarine sediment served as supplier of oxidants or electron-producing microbial habitat which evoked electrons via fast metal corrosion reactions or a complicated microbial electron transfer mechanism, respectively. Maximum power density and current density were found to be $6.90\;W/m^2$ (iron/zinc) and $7.76\;A/m^2$ (iron), respectively. Interestingly, copper wrapped with carbon cloth produced better electric performance than copper only, by 60%, possibly because the cloth not only prevented rapid corrosion on the copper surface by some degrees, but also helped growing some electron-emitting microbes on its surface. At anodes oxidation reduction potential(ORP) was kept to be stationary over time except at the very initial period. The pH reduction in the copper and copper/carbon electrodes could be a sign of organic acid production due to a chemical change in the sediment. The simple estimation of interfacial, electrical resistances of electrodes and electrolyte in the sediment cell that a key to the electricity generation should be in how to control corrosion rate or microbial electron transfer activity.

• Journal of Embryo Transfer
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• v.10 no.1
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• pp.73-82
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• 1995

large scale production of cloned embryos requires the technology of multiple generation nuclear transplantation(NT) using NT embryos as the subsequent donor nuclei. The purposes of this study were producing the second generation cloned rabbit embryos, and also to determine the electrofusion rate and in vitro developmental potential comparatively in the cloned embryos of the first and second NT generation. The embryos of 16-cell stage were collected from the mated does by flushing oviducts with Dulbecco's phosphate buffered saline(D-PBS) containing 10% fetal calf serum(FCS) at 47 hours after hCG injection In the first generation NT, the nuclear donor embryos were synchronized in the phase of Gi /S transition of 32-cell stage. The first generation NT embryos which were developed to 8-cell were synchronized in Gi /S transition phase of the following 16-cell stage and used as donor nuclei for second generation Synchronization of the cell cycle of blastomeres was induced, first, using an inhibitor of microtuble polymerization, colcemid for 10 hours to arrest blastomeres in M phase, and secondly, using a DNA synthesis inhibitor, aphidicolin for 1.5 to 2 hours to arrest them in Gi /S transition boundary. The recipient cytoplasms were obtained by removing the nucleus and the first polar body from the oocytes collected at 14 hours after hCG injection. The separated donor blastomeres were injected into the enucleated recipient oocytes by micromanipulation and were electrofused by electrical stimulation of three pulses for 60 $\mu$sec at 1.25 kV /cm in 0.28 M rnannitol solution The fused oocytes were co-cultured with a monolayer of rabbit oviductal epithelial cells in M-199 solution containing 10% FCS for 120 hours at 39$^{\circ}C$ in a 5% $CO_2$ incubator. Following in vitro culture of the first and second generation cloned embryos to blastocyst stage, they were stained with Hoechst 33342 dye for counting the number of blastomeres by fluorescence microscopy. The results obtained were summarized as follows: 1. The electrofusion rate was found to be similar as 79.4 and 91.5% in the first and second generation NT rabbit embryos, respectively. 2. The in vitro developmental potential to blastocyst stage of the second generation NT embryos (23.3%) was found significantly(p<0.05) lower, compared with that of the first generation NT embryos (56.8%). 3. The mean blastomeres counts of embryos developed to blastosyst stage following in vitro culture for 120 hours and also their daily cell cycles during the culture period were decreased significantly (p<0.05) to 104.3 cells and 1.33 cylces in the second NT generation, compoared with 210.4 cells and 1.54 cycles in the first NT generation, respectively.

• Korean Journal of Food Science and Technology
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• v.39 no.1
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• pp.55-60
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• 2007

This study used glucomannan as a fat substitute to produce low-fat patties with chicken meat, of which consumer consumption is increasing. In the case of a cooked meat patty, the crude fat content of the group treated with glucomannan was higher than that of a control when cooked. The cooking loss and reduction rate in the diameter of the control patties were higher than those of the group treated with glucomannan. Cohesiveness and chewiness of the group treated with glucomannan were higher than those of the control. As a result of sensory evaluation, there were no significant differences in the tenderness, color, odor and overall taste among the patties, but the juiciness of the group treated with glucomannan was lower than that of the control. There were no big differences in the pH of the patties during the frozen storage period. The volatile basic nitrogen (VBN) content of all of the types of patties gradually increased up to 7.97-8.56 mg% at the fourth week of storage, but these VBN values are hygienically safe. From these results, there was no large quality difference between a low-fat chicken patty to which glucomannan was added and a control. Therefore, it was confirmed that a good quality low-fat chicken patty can be made by controlling the fat and glucomannan content.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.4
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• pp.103-111
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• 2002

The purpose of this study is to investigate influence of NaCl precisely in recycling process of food waste and in places where food waste compost is used, because NaCl with food waste has caused concerns of adverse effects in the process of food waste recycling and in plates where final products is used. The influence of NaCl in composting was measured through temperature, concentration of carbon dioxide ($CO_2$) and pH. NaCl didn't cause bad effects until 1%(wet base) of NaCl concentration for composting, showed adverse effects gradually at 2% and 3% and affected composting deeply at 6%. The influence of NaCl in composting was insignificant until 3% of NaCl concentration but decomposing efficiency of organic compounds was interfered with more than 3%. NaCl concentration has to be maintained less than 1%(wet base) to minimize adverse effects of NaCl in composting however NaCl concentration with food waste used in real composting facilities is so lower than 1 %(wet base) that the bad influence in food waste composting is slight. Compost(final product) was collected from real food waste recycling facilities in A city, S city, K-Gu and S-Gu and controlled NaCl concentration artificially such as 0.5%, 0.8%, 1.2%, 1.6%, 2.0%, 2.5% and 3.0% to investigate influence of NaCl on growth of plants. In results of plant test and pot experiment, according to quality of compost sampled, the influence of NaCl is insufficient until 3% and bad effects appeared clearly more than 3%. The bad effects showed less than 3% because compost sampled was not stabilized fully.

• Analytical Science and Technology
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• v.26 no.1
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• pp.19-26
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• 2013

Gibberllic acid ($GA_3$) is one of gibberellins (GAs) that are a class of plant growth hormones that exert profound and diverse effects on plant growth and development. $GA_3$ is essentially non-UV absorbing and is difficult to assay by UV-detector. For effective extraction of gibberellic acid from fruits by using liquid-liquid extraction, optimized pH and extraction solvent were established. The selective and sensitive derivative of $GA_3$ for HPLC/UV-vis was derivatized using phenacyl bromide, and the experimental factors, including reaction time, reaction temperature and amount of derivatizing reagent and base were investigated for the effective synthesis. The derivatized $GA_3$ with phenacyl bromide was effectively analyzed by HPLC/UV-vis. The structure of derivatized $GA_3$ was confirmed by HPLC/ESI-MS. For apple, LOD and LOQ were 0.008 mg/kg and 0.027 mg/kg, respectively. For pear, LOD and LOQ were 0.003 mg/kg, 0.012 mg/kg, respectively. The established method can be applied to more effective analysis of $GA_3$ from plant and food.