• Korean Journal of Microbiology
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• v.52 no.3
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• pp.278-285
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• 2016

The bifunctional PheA protein, having chorismate mutase and prephenate dehydratase (CMPD) activities, is one of the key regulatory enzymes in the aromatic amino acid biosynthesis in Escherichia coli, and is negatively regulated by an end-product, phenyalanine. Therefore, PheA protein has been thought as useful for protein engineering to utilize mass production of essential amino acid phenylalanine. To obtain feedback resistant PheA protein against phenylalanine, we mutated by using random mutagenesis, extensively screened, and obtained $pheA^{FBR}$ gene encoding a feedback resistant PheA protein. The mutant PheA protein contains substitution of Leu to Phe at the position of 118, displaying that higher affinity (about $290{\mu}M$) for prephenate in comparison with that (about $850{\mu}M$) of wild type PheA protein. Kinetic analysis showed that the saturation curve of $PheA^{FBR}$ against phenyalanine is hyperbolic rather than that of $PheA^{WT}$, which is sigmoidal, indicating that the L118F mutant enzyme has no cooperative effects in prephenate binding in the presence of phenylalanine. In vitro enzymatic assay showed that the mutant protein exhibited increased activity by above 3.5 folds compared to the wild type enzyme. Moreover, L118F mutant protein appeared insensitive to feedback inhibition with keeping 40% of enzymatic activity even in the presence of 10 mM phenylalanine at which the activity of wild type $PheA^{WT}$ was not observed. The substitution of Leu to Phe in CMPD may induce significant conformational change for this enzyme to acquire feedback resistance to end-product of the pathway by modulating kinetic properties.

• Korean Journal of Agricultural and Forest Meteorology
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• v.4 no.1
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• pp.49-57
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• 2002

This study was conducted to find out buffer capacities of forest soils by the treatment of simulated acid rain(SAR) of four forests(Q. spp., P. rigida, P. koraiensis, L. leptolepis) in Kyunghee university's practice forest. All soils of each forest stand were treated by simulated acid rain at the level of pH 3.0, 4.0, 5.0 respectively. The result obtained from this study can be summarized as follows: Soil pH was measured by soil depth of each forest stand. The deeper soil depth was, the higher soil pH was. Also it was appeared that base saturation of sample soils was the highest as 17.42% in P. rigida stand and cation exchange capacity(C.E.C) was the highest as 29.87 me/100 g in Q. spp. stand. for responses of soil leachates to acidification treatment with pH 3.0 simulated acid rain(SAR), as simulated acid rain(SAR)-input was increased, pH value of soil leachates appeared high temporarily, but soon pH value of soil leachates had been low gradually. At the rest of pH 4.0, pH 5.0 treatment, pH value of soil leachates was high proportionably. The amounts of TBC of primary stage had a difference as pH level of simulated acid rain and forest stands. But as simulated acid rain(SAR)-input was increased. Amount of TBC was diminished. Also the amounts of TBC of primary stage in acidification treatment with pH 3.0, 4.0 simulated acid rain(SAR) was higher that of acidification treatment with pH 5.0 simulated acid rain(SAR). These trend showed obvious difference at low soil acidity and high TBC. The amounts of activity Al of primary stage appeared high as increasing the input acidity of simulated acid rain(SAR). Also, by soil depth, the amounts of Activity Al was different between A layer(0-15 cm) and AB layer(0-30 cm). There was considerable the correlation between simulated acid rain-input and activity Al change. But this was oppositional trend in soil leachates of pH 4.0, 5.0 treatment and total base cations(TBC).

• Economic and Environmental Geology
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• v.44 no.4
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• pp.273-288
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• 2011

Chon-Ashuu copper mining claim area is located, in terms of the geotectonic setting, in the northern part of the suture line which is bounded with the marginal part of Issik-kul micro-continent on the southern part of North Tien-Shan terrane. The geological blocks of Chon-Ashuu districts belong to the southern tip of Kazakhstan orocline. The rock formation of this area are composed of the continental crust or/and arc collage and the paleo-continental fragments-accretionary wedge complex of pre-Altaid orogenic materials. ASI(Alumina Saturation Index) of Paleozoic plutonic rocks in Chon-Ashuu area belong to the peraluminous and metaluminous rocks which were generated from fractional crystallization of Island and volcanic arc crusts in syn-post collisional plate. The geology of the ChonAshuu area consists of upper Proterozoic and Paleozoic rock formations. According to Harker variation diagrams for Chon-Ashuu arenaceous sedimentary rocks, the silty sandstone of Chon-Ashuu area showing the mineralogical immaturity were derived from Island arc or the marginal environments of active continent in Cambro-Carboniferous period. Numerous intrusive rocks of Chon-Ashuu area are distributed along north east trending tectonic structures and are bounded on four sides by the conjugate pattern. The most common type of the plutonic rocks are granodiorite and monzodiorite. According to the molecular normative An-Ab-Or composition (Barker, 1979), the plutonic rocks in Chon-Ashuu area are classified into tonalite - trondhjemite - granodiorite (TTG) series which are an aggregation of rocks which is the country rock of copper mineralization, that are formed by melting of hydrous mafic crust at high pressure.

• The Journal of Engineering Geology
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• v.8 no.3
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• pp.247-259
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• 1998

Groundwater quality of the natural mineral water was investigated in hydrochemical aspects in order to ensure that mineral water meets stringent health standards. There exist 20 mineral water plants in the Daebo granite and 4 mineral water plants in the Bulguksa granite, respectively. Both granite areas show some differences in water chemistry. The pH, EC, hardness, total ionic contents in groundwater of the Daebo granite area are higher relative to those of the Bulguksa granite area. The content of major cations is in the order of Ca>Na>Mg>K, while that of major anions shows the order of $HCO_3>SO_4$>Cl>F. The fact that the $Ca-Na-HCO_3$ type is most predominant among water types may reflect that the dissolution of plagioclase that is most abundant in granitic rocks plays a most important role in groundwater chemistry. Representative correlation coefficients between chemical species are variable depending on geology. In the Daebo granite area, $Ca-HCO_3(0.84),{\;}Mg-HCO_3(0.81),{\;}SiO_2-Cl(0.74),{\;}Na-HCO_3(0.70)$ show relatively good correlationships. In the Bulguksa granite area, fairly good correlationships are found among some components such as K-Mg(0.93), $K-HCO_3(0.92)$, Mg-Cl(0.92), $Cl-HCO_3(0.91)$, and K-F(0.90). According to saturation index, most chemical species are undersaturated with respect to major minerals, except for some silica phases. Groundwater is slightly undersaturated with respect to calcite, whereas it is still greatly undersaturated with respect to dolomite, gypsum and fluorite. Based on the phase equilibrium it is clear that groundwater is mostly in equilibrium with kaolinite and becomes undersaturated with respect to feldspars, evolved from the stability area of gibbsite during water-rock interaction. While the activity of silica increases, there is no remarkable increase in the acivities of alkali ions and pH, which indicates that some amounts of silicic acid dissolved from silica phases as well as feldspars were provided to groundwater. It is concluded that chemical evolution of groundwater in granite aquifers may continue to proceed with increasing pH.

• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.1
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• pp.69-76
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• 2002

This pot experiment was conducted to find out the forage productivity and contents of mineral nutrients in an orchardgrass sward as affected by the compost lime, and phosphorus applications on the newly reclaimed and arable pasture soils. This 1st part was concerned with the effect of compost application. The results obtained are summarized as follows: 1. There were considerable differences between the newly reclaimed and arable pasture soils in the soil chemical properties as fellows(newly reclaimed soil ↔ arable pasture soil): poor ↔common in pH and contents of Ca and Mg; Poor ↔ good in content of available P$_2$O$_{5}$, base saturation, and mutual balance of Ca : Mg : K; common ↔ good in K content; good ↔ good in absorption coefficient of P$_2$O$_{5}$; poor ↔ somewhat poor in CEC. The contents of available P$_2$O$_{5}$ in both soils after experiment were relatively higher in the compost block than non-compost block. It was recognized that the compost application was resulted in the CEC increase in the newly reclaimed soil. 2. The vigour at early growth of orchardgrass was better in the arable pasture soil then newly reclaimed soil. In the newly reclaimed soil, the vigour at early growth of orchardgrass was remarkedly enhanced by compost application. 3. Under the non-compost application, the orchardgrass yield was higher in the arable pasture soil by 50.9% than newly reclaimed soil. Compared with the non-compost application, the orchardgrass yields were increased in the newly reclaimed soil by 17.1% and the arable pasture soil by 7.6% by the compost application. 4. The concentrations of Ca, Mg, and P in orchardgrass were relatively higher in the arable pasture soil than the newly reclaimed soil, whereas there was no difference in the K concentration. It was recognized that the concentrations of Mg and P in orchardgrass were higher in the compost block than the non-compost block.block.

• Journal of The Korean Society of Grassland and Forage Science
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• v.9 no.1
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• pp.26-33
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• 1989

This pot experiments were conducted to find out the optimal fertilization ratios of the N:S:P anions and K:Ca:Mg cations of major nutrients in an orchardgrass/ladino clover mixed sward. The optimum ratios in equivalent basis were computed by the Homes systematic variations technique. The soil samples were collected from the newly reclaimed soils, which are located on colluvial hilly area with a good consideration for the hilly pasture development. The results were summarized as follows; 1, the optimum fertilization ratios of major nutrients for the high yields by the forage species in a mixed sward were obtained (Table 4 in detail); N:S:P = 3:l: 1 and K:Ca:Mg = 1:l: 1 for grass and grass plus legume, and N:S:P = 1:6:43 and K:Ca:Mg = 1: 3: 1 for legume in general. 2. The yield increases from the systematic variations in this mixed sward were laid in following order; N > P >S-group and K >Mg >Ca-group for grass and grass plus legume, and P >S >N-group and Ca >Mg > K-group for legume. Especially, the yields were greatly increased at the N-group for grass, and at the Pand Ca-groups for legume. 3. Soil pH-value was descreased at the Sgroup, and somewhat increased at the Ca- and Mg-groups. The content of available $P_2O_5$, CEC and base saturation were greatest with the Ca-group. 4. At the N-group, the N-contents were highest and the P-contents were lowest in grass and grass plus legume, which resulted in the highest Ca/P ratio of 2.15 among the anion groups. Whereas the highest Ca/P ratio of 9.20 in legume was obtained at the Ca-group. Legume showed in general higher Ca/P ratio and lower K/(Ca+Mg) ratio than these in grass. 5 . There were differences in the effects of systematic variations of major nutrients on the dry matter yields and the mineral yields. The optimum fertilization ratios of anions and cations for the high mineral yields were obtained (Table E), which showed differences comparing with the ratios for the high dry matter yields. The antagonis between the cations K and Mg was known from the point of mineral yields of mixed forages.

• Korean Journal of Environmental Biology
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• v.26 no.2
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• pp.57-65
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• 2008

The effects of light quality and irradiance on the growth of centric diatom, Skeletonema costatum (Jinhae Bay strain) were investigated in the laboratory. At 20$^{\circ}C$ and 30 psu, the irradiance-growth curve showed the maximum growth rate of 1.17 day$^{-1}$ with half-saturation photon flux density (PFD) (K$_s$) of 92.4 $\mu$mol photons $m^{-2}s^{-1}$, $\mu$=1.17 (I-5.28)/(I+81.8), (r=0.98), and a compensation PFD (I$_0$) was 5.28 $\mu$mol photons $m^{-2}s^{-1}$. The 10 equated to a depth of 3$\sim$5 m from March to May, 11 m in June and 4 m from July to September in Jinhae Bay. These responses suggested that irradiance at the depth near the surface layer in Jinhae Bay would provide favorable conditions for S. costatum. To assess the effects of light (i.e. wavelengths) on the growth, nine wave-lengths were used ranging from near ultraviolet to near-infrared supplied by light emitting diode. At an irradiance level of 25 $\mu$mol photons $m^{-2}s^{-1}$, S. costatum grew under wavelengths of 405, 470, 505, 525, 568 and 644 nm, but did not grow at 590 and 623 nm; whereas S. costatum grew at all wavelengths at 100 $\mu$mol photons $m^{-2}s^{-1}$. This implies that S. costatum is likely to grow well in enclosed water bodies where suspended particles absorbs most of the blue wavelengths, and dominated by yellow-orange wavelengths.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.1
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• pp.91-98
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• 2007

The aim of this study was to examine the difference of the depth of sedation using the Bispectral index assessment with and without the added submucosal Midazolam to oral Chloral hydrate and Hydroxyzine for pediatric patients. Twenty seven sedation cases were performed in this study Selection criteria included good health(ASA I), 2 to 6 years of age, the need for sedation to receive dental treatment including anesthesia, and restorative procedure over at least two teeth. Patients were randomly classified into one group taking oral Chloral hydrate(60 mg/kg) and Hydroxyzine(1 mg/kg) and the other group recieving Chloral hydrate(60 mg/kg), Hydroxyzine(1 mg/kg) and submucosal Midazolam(0.1 mg/kg). Nitrous Oxide(50%) was used for both group during sedation. Patients were monitored using a pulse oximeter and a Bispectral monitor. A behavior scale was rated as quiet(Q), crying(C), movement(M), or struggling(S) every 2 minutes watching a recorded videotape. Analysis showed a significant difference in mean Bispectral index and SD during sedation across two groups(P<0.001). The group of patients injected with submucosal Midazolam in addition to oral Chloral hydrate and Hydroxyzine showed a lower mean Bispectral index and a narrower SD. PR and SpO2 for both groups remained within the normal values. Submucosal Midazolam improved the sedation quality by deepening sedation depth without compromising safety and enabled the sedation pattern to be kept more stable.

• Tuberculosis and Respiratory Diseases
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• v.46 no.6
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• pp.836-845
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• 1999

Background : Obesity is present in the majority of adult patients with obstructive sleep apnea(OSA) and is considered to be a major risk factor for its development. A reduction in body weight has been associated with substantial improvement in the severity of apnea. However, a variety of treatment strategies for obesity have yielded limited sucess. This study was done to determine resting energy expenditure(REE) in patients with obstructive sleep apnea and the correlation between the severity of sleep apnea and REE, and to investigate whether leptin influences REE and correlated with the severity of sleep apnea in 39 patients with OSA and 45 controls matched for obesity. Method : Overnight polysomnography was performed on all subjects using standard techniques. Measurements of REE were made using a Sensormedic Vmax 229 and a canopy system. Serum leptin concentration was measured by human leptin RIA kit of LINCO Research INC. Results : REE was greater in patients with OSA compared with controls, but there was no difference between the two groups on REE%. And also there was no significant correlation between anthropometric data, polysomnographic data and REE%. Serum leptin was linearly related to body mass index(BMI), apnea index, apnea hypopnea index and lowest arterial oxygen saturation($SaO_2$) but not related to REE%. Conclusion : This study suggests the followings. Firstly patients patients with sleep apnea have a pattern of obesity characterized by energy homeostasis at an elevated body weight set-point. In order to achieve a lower body weight in these patients, it may be necessary to increase energy expenditure by increasing physical activity. Secondly leptin level was not correlated with REE, suggesting that leptin may predominantly regulate body fat by altering eating behavior rather than calorigenesis. Lastly leptin level was significantly correlated with the severity of sleep apnea. These elevated level of leptin in patients of sleep apnea may be related to the obesity, however it needs further studies to determine the relationship between the severity of sleep apnea and serum leptin.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.2
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• pp.95-100
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• 2012

This study was determined to analysis marine environmental and phytoplankton monitoring in Wando coastal waters in August during the period of 2009-2010 and provided the basic environmental data against Southwest Sea of Korea. In August, 2009, the distribution of water temperature and salinity showed an unique characteristics for all of stations, which was associated with a long duration of rainfall after July, 2009 and a lack of sunshine. In the lower of August, 2010, the stratification of water temperature and salinity was shown, which was caused by an intensive sunshine after the middle of August, 2010. Gangjin Bay and Gogeundo waters showed a highly different water temperature and transparency. It is thought that two regions have a distinct water mass and characteristics. In dissolved oxygen and oxygen saturation were higher according to higher water depth regardless of stations. In August, 2009, different dominant species occurred that Gangjin Bay showed a higher cell density of diatom, but Gonyaulax polygramma played an important role in dominant species in Gogeundo waters. It is associated with the introduction red tide water of G. polygramma occurring to southern coastal water in August, 2009. In August, 2010, diatom was extremely higher cell density compared with that of dinoflagellate that regarded as adaptive microrganism against higher quantity of suspended solid in Wando waters. Although Wando has a record of Cochlodinium red tide, this species may be difficult to grow and persist. Dominant species, diatom, play an important role in food organism for shellfish and forming a ecological lineage.