• Applied Chemistry for Engineering
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• v.29 no.5
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• pp.581-588
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• 2018

In this article, electrochemical investigation of the transfer reaction of ionizable cefotiam (CTM), an antibiotic molecule across a polarized water/1,2-dichloroethane (water/1,2-DCE) interface was studied. Ion partition diagram providing the preferred charged form of CTM in either water or 1,2-DCE phase was established via the voltammetric evaluation of the transfer process of differently charged CTM species depending upon the pH variation of aqueous solutions. Thermodynamic information including the formal transfer potential and formal Gibbs transfer energy values in addition to important pharmacokinetics including partition coefficients of ionizable CTM were also evaluated. In particular, the current associated with the transfer of CTM present at pH 3.0 aqueous solution proportionally increased with respect to the CTM concentration which was further used for developing CTM sensitive ion sensor. In order to improve the portability and convenient usage, a single microhole interface fabricated in a supportive polyethylene terephthalate film was used of which hole was filled with a polyvinylchloride-2-nitrophenyloctylether (PVC-NPOE) gel replacing 1,2-DCE, a toxic organic solvent. A dynamic range of $1-10{\mu}M$ CTM was obtained.

• Journal of the Korean Chemical Society
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• v.17 no.3
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• pp.224-228
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• 1973

In the fermentation for preparation of petroprotein by Rhodotorula sp. in $C_{12}{\sim}C_{14}$n-alkane mixture it was investigated how the effects due to the difference of chemical form of the nitrogen sources are, that is, how the inorganic nitrogen sources such as nitrates and ammonium salts and organic nitrogen source such as urea effect on the view of fermentation time and yield and how the ratios of nitrogen to carbon with $NaNo_3$ effect. Then following results were obtained: the time required to maximum growth, when $NaNo_3$ or $(NH_4)_2SO_4$ was used as nitrogen source, was 40 hrs. and 45 hrs., respectively, but when urea was used, it was 66 hrs. much longer than above nitrogen sources. On the view of yield, however, in use of the both inorganic sources, when the yield is represented as consumption of 0.1 N-NaOH, it was 0.36 and 0.38 ml, respectively, but, in the case of urea, it amounted to 0.78 ml. In the effect of the ratios of nitrogen to carbon in medium, when n-alkane mixture was added in 1 % (vol.) and N/C with $NaNo_3$ was 0.2 the best results were obtained and generally the higher the value of the ratio the better growth effects were shown.

• Journal of the Korean Chemical Society
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• v.17 no.3
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• pp.174-181
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• 1973

Dichlorodiacetatotitanium(IV) dissolves in alcohols with chemical reaction. Such solvolytic reaction of $TiCl_2(OAc)_2$with various alcohols has been studied by means of solution NMR spectroscopy and chemical analysis of the isolated products. The reaction of $TiCl_2(OAc)_2$ with primary alcohols has shown to be a quantitative two-step ligand substitution process as shown in the following: $TiCl_2(OAc)_2+ROH{\to}TiCl_2(OAc)_2(OR)+AcOH$ $TiCl_2(OAc)_2(OR)+ROH{\to}TiCl_2(OAc)_2+AcOH$The molecular form initially soluble in organic solvents has been found to be the monosubstituted species $TiCl_2(OAc)(OR)$. Alcoholysis with t-butyl alcohol has shown remarkable differences. When the mole ratio of t-butyl alcohol to $TiCl_2(OAc)_2$ is less than 1/2, the following reaction is dominant. $TiCl_2(OAc)_2+t-ButOH{\to}TiCl_2(OAc)_2+t-ButCl$However, at higher mole ratio another substitution process resembling the first step reaction with primary alcohols is competitively accompanied. The reaction with t-butyl alcohol also differs from that with primary alcohols in that only one either of the two chloro-or acetato-ligands in $TiCl_2(OAc)_2$ is subjected to substitution.

• Korean Journal of Childcare and Education
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• v.5 no.1
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• pp.41-57
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• 2009

This study investigated the teaching practice of students attending a three-year early childhood education course in K City, Gyeonggi Province, as well as the educational environments of 72 kindergartens and child care centers where they received field training and which were located in Gangseo-gu, Seoul, Incheon Metropolitan City, Bucheon, and Ilsan. After four weeks of teaching practice, those prospective teachers were surveyed for their objective opinions and current state regarding the practice guidance for students, teachers' working hours and wages, and female dominance in number among early childhood educators and heads of early childhood education institutions. Those data were collected to understand the operations of early childhood education institutions and the current teaching practice. According to the analysis results, the students of the early childhood education major said the four-week teaching practice was very helpful for them to understand the field and thus had positive receptions of it. Most of the prospective teachers felt the heaviest burden and experienced the biggest shortcomings in practical skills such as music, art, and hand play during class. They also felt a partial need for male counterparts. Those findings will help prospective teachers understand the field further before going out on the field and the teaching bodies have specific ideas about what kind of guidance is provided by kindergartens or child care centers. In addition, they will hopefully serve as basic data to form organic connections between the educational institutions and the field to produce more talented early childhood education teachers.

• Clean Technology
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• v.10 no.4
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• pp.221-228
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• 2004

Ethoxylated Nonyl Phenol Series (NP-series), nonionic surfactants, were applied for forming microemulsions in supercritical $CO_2$. Measurement results of the solubility in supercritical $CO_2$ are in the following; NP-series were high soluble in carbon dioxide in spite of the fact that those were not $CO_2$-philic surfactants traditionally well known. Water in $CO_2$ microemulsions were also formed stably. A complexation of hydrophilic lengths for $CO_2$-philic parts of NP-Series surfactants was optimized by NP-4 surfactant(N=4) for forming the microemulsions through the experiments. Formation of microemulsions was confirmed by measuring the UV-Visible spectrum through a spectroscopic method and existence of water in the microemulsions was confirmed as well. In order to apply it for a metal surface treatment or electroplating, an experiment for forming acid(organic, inorganic) solution in $CO_2$ microemulsions was carried out. Ionic surfactant in the reaction to an acid solution became unstable to form microemulsions, however, nonionic surfactant was formed stably in the reaction. Results of the study will be utilized for expanding the application scope of supercritical $CO_2$ which is an environmental-friendly solvent.

• Korean Journal of Environmental Agriculture
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• v.26 no.1
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• pp.49-54
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• 2007

This study was conducted to determine effects of composted livestock manure application on soil nutrient change. PVC pot $(30\times100cm)$ was filled with either volcanic ash soil (Gujwa series) or non-volcanic ash soil (Aewol series) and the 20 cm surface soils were applied with composted livestock manures of cattle pig and poultry at the rates of 0, 50, 100 and 150 ton/ha, respectively. After 210 days soils samples of phosphate, potassium, calcium, and magnesium affected by application of the compost. The applied composted were equivalent to the application of organic matter of $23\sim111$ ton/ha and nitrogen of $80\sim450$ ton/ha. Availability rate of phosphate after the application of composted livestock manures ranged from 1.6 to 91.7% according to the different composted. It was much higher in the non-volcanic ash soil than in the volcanic ash soil. Availability rate of potassium fractional recovery rate change ranged from 22 to 94% according to the different manures. It was larger in the composted Availability rate of calcium 38 to 93% and $9\sim90%$ in volcanic ash soil and non-volcanic ash soil, respectively, It was higher in the composted manures followed by cattle and composted pig manures. Availability rate magnesium ranged from 12 to 41% and $1\sim9%$ in volcanic ash soil and non-volcanic ash soil, respectively. The rate was higher in the composted poultry manure followed by pig and composted cattle manures.

• Research in Plant Disease
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• v.24 no.1
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• pp.33-40
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• 2018

This study was conducted to evaluate the antifungal activity of 19 agro-materials that have been registered for organic cultivation in Korea, after inoculation of pear leaves with Venturia nashicola and Gymnosporangium asiaticum. In V. nashicola, most of the nine agro- materials containing sulfur and copper completely inhibited spore germination, and some of the spores that germinated did not form appressoria. However, in only lime sulfur, Neobordeaux (cupric sulfate), and Wheengaris (sulfur)showed antifungal activity against G. asiaticum. Among the agro-materials containing plant extracts, Wheengarujaba (wood vinegar+spirits+rhubarb) inhibited conidial germination in V. nashicola and G. asiaticum by 100% and 71.6%, respectively. Among the agro-materials containing antifungal microorganisms, Cheongotan (Streptomyces griseus) reduced spore germination rate of V. nashicola to 88.8%; moreover, formation of appressoria or intracellular accumulation was not observed. Application of Topsid (Paenibacillus polymyxa) reduced spore germination rates in V. nashicola and G. asiaticum to 71.0% and 90.6%, respectively, and the formation of appressoria was not observed. Studying the antifungal activity of agro-materials because of cumulative applications under the field conditions is necessary, owing to their contact fungicidal effect and the induced-resistance by microbial metabolites and natural compounds.

• Journal of Physiology & Pathology in Korean Medicine
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• v.30 no.1
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• pp.27-32
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• 2016

Streptococcus mutans plays a virtal role in trigering dental caries establishment due to its ability to synthesize two significant factors. The two factors are organic acids and glucans. The former demineralized dental enamel and the latter mediates the attachment of bacteria to tooth surface. It is believed that demineralization of dental enamel and attachment of bacteria are the crucial events that indicate and develop dental caries. For this reason, we studied the effect of the ethanol extracts of Radix Pulsatillae on the growth and acid production of S. mutans. Ethanol extracts of the Radix Pulsatillae showed concentration dependent inhibitory activity against the growth and acid production of S. mutans, and produced significant inhibition compared to the control groups (p<0.05). The extracts inhibited S. mutans adherence to hydroxyapatite treated with saliva, and cell adherence was repressed by Radix Pulsatillae. the ethanol extract of Radix Pulsatillae showed remarkable inhibition of glucosyltransferase, which synthesizes water insoluble glucan form sucrose. Phytochemical analysis showed Radix Pulsatillae contained major components such as phenolic compounds, glycosides, steroids, terpenoid, and saponin. These results suggest that Radix Pulsatillae may have anti-cariogenic properties, which may be related with major components such as phenolic compounds, glycosides, steroids, terpenoid, and saponin.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.3
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• pp.392-400
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• 2004

This research uses the $TiO_2$/UV process to verify the most suitable condition and possibility to dispose dyeing wastewater that contains pigment and a large amount of pollutants. For this, this research has enforced experiments that compare photo adsorption, photolysis, and photo catalyst oxidation reaction, and also evaluated and analyzed the change of pH and $TiO_2$ dosage, irradiation rates of ultraviolet rays and the dosage change and injection method of $H_2O_2$. According to the results of the dyeing wastewater experiment of storehouse catalyst that uses the new form of $TiO_2$, the photo catalyst oxidation reaction proved to be more effective than photo adsorption and photolysis; 35%, 21% in the case of $TCOD_{cr}$ and 39%, 28% in the case of chromaticity. Taking into consideration the reaction time, amount of photo catalyst reaction and irradiation amount of ultraviolet rays, the decomposition efficiency of pH change proved to be most effective at pH 4. On the whole, the acidity area proved to be effective in dyeing water exclusion than neutral and alkalinity areas. Having evaluated the influence of $TiO_2$ dosage, not only does the decomposition efficiency continuously improve as the $TiO_2$ dosage increases but the shielding effect does not occur also when the $TiO_2$ is at a fixed state. The influence of ultraviolet irradiation amount concluded in the result that as the ultraviolet irradiation amount increases the decomposition efficiency continually increased, but in the case of chromaticity when the irradiation amount was higher than 37.8mW/cm2 the removal efficiency is slowed remarkably. The influence of $H_2O_2$ dosage evaluation reached the results that although the decomposition efficiency increases with the increase of $H_2O_2$ dosage, when above 150mg (total dosage: 1200mg) $H_2O_2$ consumes OH radical itself and reduces the decomposition efficiency. Also in the case of the $H_2O_2$ injection method rather than injecting in the whole amount of $H_2O_2$ (1200mg) needed at the beginning all at once, injecting divided quantities of $H_2O_2$ whenever the electric current density falls below 10mgfl reduces the wases of OH radical due to an excess of $H_2O_2$ and in tum heightens the decomposition efficiency.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.5
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• pp.646-653
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• 2013

Four crossbred Sindhi heifers with an average body weight (BW) of 135 kg and a mean age of 17 months were used to investigate the effect of feeding different combinations of rice straw and ensiled water hyacinth (EWH) supplemented with a source of protein in the form of cottonseed cake (CSC) on intake and digestibility. Four treatments consisting of graded levels of EWH were arranged in a $4{\times}4$ Latin square. The levels of EWH were set at: 0 (EWH0), 15 (EWH15), 30 (EWH30), and 45% (EWH45) of an expected total dietary dry matter (DM) intake of 30 g total DM per kg BW per day. Rice straw was offered ad libitum, while CSC was given at a fixed level of 5 g DM/kg body weight (BW). Voluntary intake and digestibility were measured consecutively in the 4 experimental periods which each lasted 28 days. The crude protein (CP) content of EWH, rice straw and CSC were 174, 53 and 370 g/kg DM, respectively. Rice straw had the highest neutral detergent fibre (NDFom) content (666 g/kg DM), followed by EWH (503 g/kg DM) and the lowest content was 418 g/kg DM in the CSC. The actual EWH contents in the consumed diets were 0, 17, 32 and 52% for EWH0, EWH15, EWH30 and EWH45, respectively. Rice straw intake decreased with level of EWH offered from 3049 for EWH0 to 1014 g/day for EWH45. Crude protein intake was 16, 25 and 33% higher (p<0.001) in EWH15, EWH30 and EWH45 treatments, respectively, as compared to EWH0. Digestibility of organic matter (OM), CP, NDFom and acid detergent fibre (ADFom) increased with increasing level of EWH offered. The highest OM digestibility (72.2%) was found for treatment EWH45 and the lowest (47.4%) for treatment EWH0. In spite of similar dietary CP contents, CP digestibility increased by 21 (EWH15), 31 (EWH30) and 40% (EWH45) with increasing level of EWH in comparison with treatment EWH0. It is concluded that increasing level of EWH in cattle diets considerably improved CP intake and digestibility of nutrients.