• Microbiology and Biotechnology Letters
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• v.2 no.2
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• pp.79-82
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• 1974

Present experiments were designed to estimate the effects of pretreatments by various kinds of alkalis to the agricultural wastes such as cereal straws as the substrate on the production of cellulosic single-cell protein. Among the various kinds of alkalis NaOH was proved to be the most effective on improving the digestibility of cellulose by the bacteria isolated. NH$_4$OH which is inferior to NaOH in the effectiveness of treatment might have more economic advantage in the price, and the ammonium salt resulted from the neutralization can be used as the nitrogen source by bacteria. The treatment with higher concentration than 1 normality of NH$_4$OH didn't increase the productivility of cell mass. About five per cent of (NH$_4$)$_2$SO$_4$ in medium resulted from the neutralization didn't have any influence in the cell mass productivility. Futhermore, the cell mass productibility was higher in the case of neutralization than alkali free washing. The digestibility of straws was increased from 7.9％ to 46.0％ by NH$_4$OH treatment, and 6.3∼6.45g of dry cell were obtained from 40g of NH$_4$OH treated straws. In the case of NaOH treatment, 8.6g of cell mass was obtained from 40g of substrate.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.5
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• pp.340-349
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• 2013

The present paper investigates the availability of seawater as the absorbents to capture carbon dioxide ($CO_2$) emitted from the coal fired power plant (CFPP). For the purpose of the study, readily obtainable alkali materials in CFPP such as coal fly ash (FA), NaOH and $Ca(OH)_2$ are added to seawater to prepare the absorbents and their $CO_2$ capture performances are discussed. FA can be effectively used the additives to increase $CO_2$ capture capacity of seawater to a some extent. This is ascribed that some alkali components in FA are leached into seawater and they contribute to $CO_2$ capture in the solution. However, their leaching amount and rate are restricted by the various ions in seawater. The performance of NaOH added seawater is even lower than that of NaOH added water because $OH^-$ is substantially consumed on $Ma(OH)_2$ production prior to carbonation. $CO_2$ absorption capacity of $Ca(OH)_2$ added seawater is slightly larger than that of $Ca(OH)_2$ added water. This is because that $Ca^{2+}$ which originally present in raw seawater can participate in carbonation reaction.

• Nutrition Research and Practice
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• v.9 no.2
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• pp.158-164
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• 2015

BACKGROUND/OBJECTIVES: Vitamin D deficiency is common in hemodialysis patients. The aim of this study was to identify whether or not sun exposure and dietary vitamin D intake have effects on serum 25-hydroxyvitamin D (25(OH)D) status in hemodialysis (HD) patients. The objective was to identify the main determinants of serum vitamin D status in the study subjects. SUBJECTS/METHODS: A cross-sectional study of 47 HD patients (19 males and 28 females) was performed. We assessed serum 25(OH)D and $1,25(OH)_2D$ levels between August and September 2012 and analyzed the prevalence of vitamin D deficiency in HD patients. To evaluate the determinants of serum 25(OH)D levels, we surveyed dietary vitamin D intake, degree of sun exposure, and outdoor activities. To compare biological variables, serum 25(OH)D was stratified as below 15 ng/ml or above 15 ng/ml. RESULTS: Mean 25(OH)D and $1,25(OH)_2D$ levels were $13.5{\pm}5.8ng/ml$ and $20.6{\pm}11.8pg/ml$, respectively. The proportions of serum 25(OH)D deficiency (< 15 ng/ml), insufficiency (15-< 30 ng/ml), and sufficiency (${\geq}30ng/ml$) in subjects were 72.4%, 23.4%, and 4.3%, respectively. Prevalence of vitamin D deficiency in female patients was 78.6%, whereas that in males was 63.2% (P = 0.046). Vitamin D intake and sun exposure time were not significantly different between the two stratified serum 25(OH)D levels. Dietary intake of vitamin D did not contribute to increased serum 25(OH)D levels in HD patients. The main effective factors affecting serum 25(OH)D status were found to be the sun exposure and active outdoor exercise. CONCLUSIONS: Hypovitaminosis D is common in HD patients and is higher in females than in males. Sun exposure is the most important determinant of serum 25(OH)D status in HD patients.

• Korean Journal of Materials Research
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• v.22 no.1
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• pp.54-60
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• 2012

The particle size of MgO was examined as a function of the Na content in $Mg(OH)_2$ powders and the calcination temperature. $Mg(OH)_2$ suspension was obtained by dropwise precipitation of $Mg(NO_3)_2{\cdot}6H_2O$ and NaOH solutions. The suspension was diluted by varying the dilution volume ratio of distilled water to $Mg(OH)_2$ suspension to change the Na salt concentration in the suspension. $Mg(OH)_2$ slurry was filtered and dried at $60^{\circ}C$ under vacuum, and then its $Mg(OH)_2$ powder was calcined to produce MgO with different amount of Na content at $500\sim900^{\circ}C$ under air. Investigation of the physical and chemical properties of the various MgO powders with dilution ratio and calcination temperature variation was done by X-ray diffraction, transmission electron microscopy, BET specific surface area and thermal gravimetric analysis. It was observed that MgO particle size could depend on the condition of calcination temperature and dilution ratio of the $Mg(OH)_2$ suspension. The particle size of the MgO depends on the Na content remaining in the $Mg(OH)_2$ powder, which powder was prepared by changing the dilution ratio of the $Mg(OH)_2$ suspension. This change increased as the calcination temperature increased and decreased as the dilution ratio increased. The growth of MgO particle size according to the increase of temperature was more effective when there was a relatively high content of Na. The increase of Na content lowered the temperature at which decomposition of $Mg(OH)_2$ to MgO took place, thereby promoting the crystal growth of MgO.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.04a
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• pp.101-110
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• 2011

The experiment was conducted to evaluate the different NaOH pretreatment concentrations (0.25%, 0.50%, 0.75%, and 1.00%) on enzymatic saccharification (with cellulase, and ${\beta}$-glucosidase) and fermentation (by Saccharomyces cerevisiaeKCCM 11304) for bioethanol production from rice straw and rice husk. Pretreatment of rice straw and rice husk were conducted under both natural and powder state to observe the potentiality of the biomass condition (natural and powder state). In this study, glucose and ethanol production were increased with the increase of NaOH percentage for both rice straw and rice husk (natural and powder state). For rice straw, the highest amount of glucose was obtained in 1.00% NaOH pretreatment (0.81 g $g^{-1}$ in a natural, and 0.63 g $g^{-1}$ in a powder state pretreatment). Similarly, for rice husk, the highest amount of glucose was obtained in 1.00% NaOH pretreatment (0.47 g $g^{-1}$ in a natural, and 0.46 g $g^{-1}$ in a powder state pretreatment). However, 0.75% NaOH pretreatment resulted in glucose yield near about 1.00% NaOH pretreatment for both rice straw and rice husk (natural and powder state). On the other hand, for rice straw, the highest amount of ethanol was obtained in 1.00% NaOH pretreatment (0.36 g $g^{-1}$ in a natural, and 0.31 g $g^{-1}$ in a powder state pretreatment). In addition, for rice husk, the highest amount of ethanol was also obtained in 1.00% NaOH pretreatment (0.24 g $g^{-1}$ in a natural, and 0.23 g $g^{-1}$ in a powder state pretreatment). Moreover, 0.75% NaOH pretreatment resulted in ethanol yield near about 1.00% NaOH pretreatment for both rice straw and rice husk (natural and powder state). It was confirmed that higher amount of NaOH use is cost effective. Moreover, higher amount of glucose and ethanol was observed when powder was prepared after pretreatment. So 0.75% NaOH pretreatment in a natural state is supposed to be suitable for enzymatic saccharification and fermentation for bioethanol production.

• Journal of the Korea Institute of Building Construction
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• v.18 no.3
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• pp.203-210
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• 2018

Corrosion of the rebar is one of the main factors affecting the durability of reinforced concrete in the world which lead to the failure of the reinforced concrete structures. In this research, a new method of fixing $CO_2$ is practiced to improve the carbonation resistance of the concrete. Brucite($Mg(OH)_2$), a kind of common $CO_2$ fixation materials, was added into ordinary Portland cement paste. Samples containing 0%, 5%, 10%, and 15% $Mg(OH)_2$ were exposed to an accelerated carbonation curing regime with 20% concentration of $CO_2$, 60% relative humidity, and a temperature of $20^{\circ}C$ until tested at 3d, 7d, 14d and 28d. After 28d of $CO_2$ accelerated curing, in the paste containing $Mg(OH)_2$, magnesian calcite was detected by SEM-EDX. Meanwhile, the paste containing $Mg(OH)_2$ exhibit the better pore distribution than ordinary Portland cement paste and the compressive strength of the cement paste containing $Mg(OH)_2$ were more than 50Mpa.

• Korean Journal of Materials Research
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• v.21 no.11
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• pp.587-591
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• 2011

The effect of the precipitator (NaOH, $NH_4OH$) and the amount of the precipitator (150, 200, 250, 300 ml) on the formation of $Fe_3(PO_4)_2$, which is the precursor used for cathode material $LiFePO_4$ in Li-ion rechargeable batteries was investigated by the co-precipitation method. A pure precursor of olivine $LiFePO_4$ was successfully prepared with coprecipitation from an aqueous solution containing trivalent iron ions. The acid solution was prepared by mixing 150 ml $FeSO_4$(1M) and 100 ml $H_3PO_4$(1M). The concentration of the NaOH and $NH_4OH$ solution was 1 M. The reaction temperature (25$^{\circ}C$) and reaction time (30 min) were fixed. Nitrogen gas (500 ml/min) was flowed during the reaction to prevent oxidation of $Fe^{2+}$. Single phase $Fe_3(PO_4)_2$ was formed when 150, 200, 250 and 300 ml NaOH solutions were added and 150, 200 ml $NH_4OH$ solutions were added. However, $Fe_3(PO_4)_2$ and $NH_4FePO_4$ were formed when 250 and 300 ml $NH_4OH$ was added. The morphology of the $Fe_3(PO_4)_2$ changed according to the pH. Plate-like lenticular shaped $Fe_3(PO_4)_2$ formed in the acidic solution below pH 5 and plate-like rhombus shaped $Fe_3(PO_4)_2$ formed around pH 9. For the $NH_4OH$, the pH value after 30 min reaction was higher with the same amount of additions of NaOH and $NH_4OH$. It is believed that the formation mechanism of $Fe_3(PO_4)_2$ is quite different between NaOH and $NH_4OH$. Further investigation on this mechanism is needed. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and the pH value was measured by pH-Meter.

• Journal of Life Science
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• v.32 no.10
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• pp.749-761
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• 2022

This study evaluated the antioxidizing and antiproliferative effects of Angelica japonica extract and its solvent-partitioned fractions. A dried sample of the halophyte A. japonica was extracted twice using methylene chloride (CH₂Cl₂) and extracted twice again using methanol (MeOH). The combined crude extracts were then fractionated by solvent polarity into distilled water (water), n-butanol (n-BuOH), 85% aqueous methanol (85% aq.MeOH), and n-hexane fractions. The antioxidant activities of the crude extracts and their solvent-partitioned fractions were assessed according to their DPPH radical and peroxynitrite scavenging abilities, formation of intracellular reactive oxygen species (ROS), DNA oxidation, NO production, and ferric reducing antioxidant power (FRAP). The crude extract showed significant antioxidant activity in the overall antioxidizing bioassay systems. Among solvent-partitioned fractions, good antioxidant activities were observed in n-BuOH and 85% aq.MeOH fractions and significantly correlated with the polyphenol and flavonoid contents of the samples. Furthermore, all samples tested, including the crude extract, not only showed cytotoxic effects against human cancer cells (AGS, HT-29, MCF-7, and HT-1080) but also prevented cell migration in a dose-dependent manner in the wound healing assay using HT 1080. Among the solvent-partitioned fractions, the 85% aq.MeOH fraction most effectively inhibited the invasion of HT-1080 cells. Therefore, these results suggest that A. japonica may be a potential antioxidizing and antiproliferative agent.

• 한국연소학회:학술대회논문집
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• 2004.11a
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• pp.91-96
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• 2004

Simultaneous CH and OH planar laser induced fluorescence(PLIF) and stereoscopic particle image velocimetry (PIV) measurements have been developed to investigate the local flame structure of turbulent premixed flames. The developed simultaneous two radical concentrations and three component velocity measurements on a two-dimensional plane was applied for relatively high Reynolds number turbulent premixed flames in a swirl stabilized combustor. All measurements were conducted for methane-air premixed flames in the corrugated flamelets regime. Strong three-dimensional fluctuation implies that misunderstanding of the flame/turbulent interactions would be caused by the analysis of two-component velocity distribution in a cross section. Furthermore, comparisons of CH-OH PLIF and three-component velocity field show that the burned gases not always have high-speed velocity in relatively high Reynolds number turbulent premixed flame. The Reynolds number dependence of the flame front was clearly captured by the simultaneous CH-OH PLIF and stereoscopic PIV measurements.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.211-213
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• 2014

Simultaneous measurements of planar laser-induced fluorescence (PLIF) of OH radicals and particle image velocimetry (PIV) were used to investigate the strain rates and OH structure characteristics of turbulent syngas non-premixed jet flames close to blowoff. Mean values of the maximum principal strain rate on OH layer decreases with the axial distance, and its standard deviation is significantly large upstream. Strain rate on stabilization region of the stable flame is only about a half of that of the flame near blowoff.