• Applied Biological Chemistry
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• v.40 no.1
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• pp.53-57
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• 1997

The rate of hydrolysis of insecticidal 1-(6-chloro-3-pyridylmethyl) -2-nitro-iminoimidazolidine (common name; imidacloprid) have been investigated in 15%(v/v) aqueous dioxane at $45^{\circ}C$. From the kinetics and non-kinetics data such as pH-effect, solvent effect(m=0.04, n=0.30 IT m<${\Delta}H^{\neq}=16.14kcal{\cdot}mol^{-1}\;&\;{\Delta}S^{\neq}=-0.03e.u.$), rate equation ($k_{obs.}=4.56{\times}10^{-3}[OH^-]$) and analysis of hydrolysis product, 1-(6-chloro-3-pyridylmethyl-2)-imidazolidinon, the hydrolysis mechanism of imidacloprid is proposed that the specific base catalyzed hydrolysis($K_{OH^-}$) through nucleophilic addition-elimination ($Ad_N-E$) mechanism proceed via intermediate, 1-(6-chloro-3- pyridylmethyl)-2-hydroxy-2-imidazolidinylisonitraminate (I) and ${\beta}$-3-(6-chloro-3-pyridylmethyl)aminoethyl-1-nitrourea(III). And the half-life(t1/2) of hydrolytic degradation at pH 8.0 and $45^{\circ}C$ was about 4.5 months.

• Journal of Animal Environmental Science
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• v.17 no.1
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• pp.49-54
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• 2011

Animal manure is produced annually 43.7 million tonnes in Korea. Among them, about 85.6 % are used as compost or liquid fertilizer to the agricultural land. The animal manure can be effectively utilized by mixing with organic byproducts that result in generation of biogas from anaerobic co-digestion process. This study aimed to optimize the content of total solid materials (TS) and determine the effect of organic byproduct on the co-digestion process. Prior to the byproduct treatments, determination of proper content of TS was conducted by controlling at 5 or 10 %. For the byproduct treatments, swine manure without adding the byproduct was used for control treatment, and swine manure mixed with either corn silage or kitchen waste was used for other treatments. Volume of biomethane ($CH_4$) generated from digested materials was quantified before and after byproduct treatments. In result, a 1.4-fold higher biomethane, about 0.556 L/$L{\cdot}d$, was produced when the content of TS was controlled at 10 %, compared at 5 %, about 0.389 L/$L{\cdot}d$. When the swine manure was mixed with the corn silage or kitchen waste, a two-fold higher biomethane was produced, about 1.theand 1.0heL/$L{\cdot}d$, respectively, compared to the control treatment. Biogas production from organic dry matter (odm) was a3, 362eand 2h6 L/kg odm${\cdot}$d for control, corn silage, and kitchen waste treatment, respectively. The lower biogas production in the treatment of kitchen waste than that of corn silage is associated with its relatively high odm contents. The methane concentration during the whole process ranged from 40 at the beginning to 70 % at the end of process for both the control and kitchen waste treatments, and ranged from 52 to 70 % for the corn silage treatment. Hydrogen sulfide ($H_2S$) concentration ranged between 350 and 500 ppm. All the integrated results indicate that addition of organic byproduct into animal manure can double the generation of biogas from anaerobic fermentation process.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.2
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• pp.161-167
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• 2013

The aim of this study was to investigate the protective effects of methanolic extract from perilla (Perilla frutescens Britt var. japonica) leaves (PLME) on oxidative injury from hydrogen peroxide ($H_2O_2$) in human HaCaT keratinoctyes. Cells were co-incubated with various concentrations (0~200 ${\mu}g/mL$) of PLME for 24 hr, and then exposed to $H_2O_2$ (500 ${\mu}M$) for 4 hr. $H_2O_2$ significantly decreased cell viability (p<0.05). However, PLME provided protection from $H_2O_2$-induced HaCaT cell oxidation in a dose-dependent manner. To further investigate the protective effects of PLME on $H_2O_2$-induced oxidative stress in HaCaT cells, the cellular levels of lipid peroxidation, and antioxidant enzymes (including superoxide dismutase (SOD), glutathione peroxidase (GSH-px) and catalase (CAT)) were measured. PLME decreased cellular levels of lipid peroxidation, and also increased the activities of antioxidant enzymes. In addition, the antioxidant activities of PLME were also determined by DPPH and hydroxyl (${\cdot}OH$) radical scavenging assay, and major antioxidant compounds of PLME were measured by colorimetric methods. DPPH and ${\cdot}OH$ radical scavenging activities of PLME increased in a dose dependent manner and was similar to the DPPH scavenging activity of ascorbic acid at 50 ${\mu}g/mL$; however PLME activities were stronger than ascorbic acid (50 ${\mu}g/mL$) in the ${\cdot}OH$ scavenging assay. The amounts of antioxidant compounds, including total polyphenolics, total flavonoids, and total ascorbic acid from PLME were $52.2{\pm}1.1$ mg gallic acid (GAE)/g, $33.7{\pm}4.7$ mg rutin (RUE)/g, and $17.0{\pm}0.5$ mg ascorbic acid (AA)/g, respectively. These results suggest that PLME has a strong free radical-scavenging activity and a protective effect against $H_2O_2$-induced oxidative stress in the keratinocytes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.3
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• pp.360-366
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• 2014

Kimchi is a Korean traditional fermented food with various health functionalities. However, the protective effects of kimchi against Alzheimer's disease (AD) have not been studied yet. In this study, the protective activities of kimchi extract against oxidative stress and AD were investigated in an amyloid beta ($A{\beta}$)-induced AD model using ICR mice. Kimchi extract exerted strong scavenging activities against 1,1-diphenyl-2-picrylhydrazyl and hydroxyl radical. In addition, T-maze, object cognition, and water maze tests were carried out using the AD model. The $A{\beta}_{25-35}$-injected groups showed impairment of cognition and memory. However, the abilities of novel object recognition and new route awareness were improved by administration of kimchi extract (100 and 200 mg/kg/day) for 2 weeks. Furthermore, the results on water maze test indicated that kimchi extract exerted protective activity against cognitive impairment induced by $A{\beta}_{25-35}$. The present study suggested that kimchi protected against $A{\beta}$-induced impairment of memory and cognition as well as attenuated oxidative stress.

• Resources Recycling
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• v.17 no.6
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• pp.10-16
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• 2008

In this study, the crystallization of cerium carbonate from cerium chloride solution by addition of ammonium bicarbonate was investigated. The concentration of reactants such as cerium chloride(0.5-2M) and ammonium bicarbonate, and reaction temperature($20-60^{\circ}C$) have a great effect on the crystal types of cerium carbonate such as lanthanite-type cerium carbonate[$Ce_2(CO_3)_3{\cdot}8H_2O$] and tengerite-type cerium carbonate[$Ce_2(CO_3)_3{\cdot}2.5H_2O$]. The crystallinity of cerium carbonate changed from lanthanite to tengerite as the concentration of reactants and reaction temperature increased. Transformation of cerium carbonate hydrate was transformed to cerium hydroxy carbonate depended on the drying conditions. Cerium carbonate of lanthanite and tengerite has the shape of aggregates with plate type crystal, and the size of lanthanite and tengerite crystal was $3{\mu}m$ and $5{\mu}m$, respectively. Cerium hydroxy carbonate has the shape of aggregates with needle type crystal, and the crystal size was about $7{\mu}m$.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.3
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• pp.441-451
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• 2000

Sludge produced from water treatment plants contains plenty of aluminum due to addition of coagulants, polyaluminum chloride(PACI) which has been widely used in most of water treatment plants. however. the whole of PACI is imported from other countries. In this research. the effective methods for recycling PACI from sludge of water treatment plants were developed and evaluated. Aluminum chloride hexahydrate($AlCl_3{\cdot}6H_2O$) was obtained by sparging HCl gas aluminum extracted from sludge using hydrochloric acid (HCI). This aluminum chloride hexahydrate was solidified by decomposition at $180^{\circ}C$. and dissolved in water to produce PACI. The optimum extraction rate was obtained at the condition of 10 minutes of reaction time. $105^{\circ}C$ of reaction temperature. 27.65%(W/W) of HCI concentration. The KS experiment proved that manufactured aluminum chloride hexahydrate was 98.7% degree and the recycled PACI coagulants agreed with the KS standard. The optimum temperature of decomposition was $180^{\circ}C$ and the basicity of the PACI was decided upon the extent of decomposition The compared experiments between purchased coagulant and manufactured coagulant presented that both coagulants had same performance for turbidity, DOC, $UV_{254}$ absorbance. and chlorophyll-a.

• Horticultural Science & Technology
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• v.31 no.1
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• pp.14-23
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• 2013

This study evaluated the influence of light quality and intensity during healing and acclimatization on the $CO_2$ exchange rate, growth, and morphogenesis of grafted pepper (Capsicum annuum L.) transplants, using a system for the continuous measurement of the $CO_2$ exchange rate. C. annuum L. 'Nokkwang' and 'Tantan' were used as scions and rootstocks, respectively. Before grafting, the transplants were grown for four weeks in a growth chamber with artificial light, where the temperature was set at $25/18^{\circ}C$ (light/dark period) and the light period was 14 hours $d^{-1}$. The grafted pepper transplants were then healed and acclimatized under different light quality conditions using fluorescent lamps (control) and red, blue, and red + blue light-emitting diodes (LEDs). All the transplants were irradiated for 12 hours per day, for six days, at a photosynthetic photon flux (PPF) of 50, 100, or 180 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. The higher PPF levels increased the $CO_2$ exchange rate during the healing and acclimatization. A smaller increase in the $CO_2$ exchange rates was observed in the transplants under red LEDs. At a PPF of 180 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, the $CO_2$ exchange rate of the transplants irradiated with red LEDs was lowest and it was 37% lower than those irradiated with fluorescent lamps. The $CO_2$ exchange rates of transplants irradiated with blue LEDs was the highest and 20% higher than those irradiated under fluorescent lamps. The graft take was not affected by the light quality. The grafted pepper transplants irradiated with red LEDs had a lower SPAD value, leaf dry weight, and dry matter content. The transplants irradiated with blue LEDs had longer shoot length and heavier stem fresh weight than those irradiated with the other treatments. Leaves irradiated with the red LED had the smallest leaf area and showed leaf epinasty. In addition, the palisade and spongy cells of the pepper leaves were dysplastic and exhibited hyperplasia. Grafted pepper transplants treated with red + blue LEDs showed similar growth and morphology to those transplants irradiated with fluorescent lamps. These results suggest that high-quality grafted pepper transplants can be obtained by healing and acclimatization under a combination of blue and red lights at a high PPF level.

• Fire Science and Engineering
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• v.24 no.1
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• pp.90-94
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• 2010

In this study it is intended to review the moving characteristics of smoke by performing visualization simulation for the calculation of the optimal smoke exhaust air volume in case a fire occurs in tunnels where transverse ventilation is applied, and to obtain basic data necessary for the design of smoke exhaust systems by deriving optimal smoke exhaust operational conditions under various conditions. As a result of this study, if it was assumed 0 critical velocity in the tunnel, the smoke exhaust air volume was limited within 250 meter in the road-tunnel disaster prevention indicator and the exhaust efficiency was from 55.1% to 95.8% in the result of this study. If the wind velocity is in the tunnel, the exhaust rate intends to increase rapidly and the exhaust efficiency is decreased. In addition, if the wind velocity is increased, the exhaust rate should be increased in compared with the generation rate of smoke in maximum 1.8 or 1.04 times. In this study, when the wind velocity is in the tunnel, the limited exhaust rate is $84m^3/s{\cdot}250m$. And if it was assumed 1.75 m/s critical velocity in the tunnel, the exhaust rate would be defined $393m^3/s{\cdot}250m$($Q_E$ = 80 + 5Ar).

• Korean Chemical Engineering Research
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• v.54 no.1
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• pp.135-139
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• 2016

We developed a liquid-liquid extraction method using an inorganic salt to dramatically improve the recovery efficiency of the anticancer agent paclitaxel from plant cell cultures. As a result of liquid-liquid extraction using a diverse types of inorganic salt (NaCl, KCl, $K_2HPO_4$, $NaH_2PO_4$, $NaH_2PO_4{\cdot}2H_2O$), NaCl gave the highest yield (~96%) and lowest partition coefficient (0.053) of paclitaxel. The optimal NaCl/solvent ratio, methylene chloride/MeOH ratio, and pure paclitaxel content for liquid-liquid extraction using NaCl were 1% (w/v), 26% (v/v), and 0.066% (w/v), respectively. Under the optimal conditions developed in the present method, most of the paclitaxel (~96%) was recovered from biomass by a single extraction step. In addition, this method facilitated 3-fold higher recovery efficiency of paclitaxel in a shorter extraction number than the conventional liquid-liquid extraction method.

• ALGAE
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• v.20 no.2
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• pp.121-125
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• 2005

The modern integrated fish-seaweed mariculture has been tested to reduce the environmental impacts of an intensive fed culture. To obtain the best seaweed bioremediation performance, the effects of therapeutants used for fish disease control on the selected seaweed species should be considered. As a selected seaweed, Porphyra yezoensis was tested with six commercial antibiotics including erythromycin thiocyanate_A, erythromycin thiocyanate_B, oxytetracycline, doxycycline, pefloxacin, and amoxicillin trihydrate under the batch incubation at a photon flux density of 10 $\mu$mol ${\cdot}m^{-2}\;{\cdot}\;s^{-1}$ at 15$^{\circ}C$. Among the tested commercial antibiotics, erythromycin thiocyanate_A, erythromycin thiocyanate_B, oxytetracycline, and doxycycline showed decreases in Fv/Fm, the photochemical efficiency of photosystem II, with a dose-dependant and time-dependant manner. From the quenching analysis of chlorophyll fluorescence, three differential patterns were observed in the antibiotics-treated Porphyra: (1) high nonphotochemical quenching (NPQ) and low photochemical quenching (qP) in the cases of Erythromycin thiocyanate_B and amoxicillin trihydrate, (2) high NPQ and high qP in the case of pefloxacin and (3) low NPQ and low qP in the case of oxytetracycline. These results indicated that antibiotics affected in various ways on the photosynthetic apparatus, reflecting differential lesion sites of antibiotics. In addition, the rates of ammonium uptake also decreased with a decrease of Fv/Fm in P. yezoensis thalli treated with erythromycin thiocyanate_B and oxytetracycline. Therefore, the four antibiotics mentioned could affect the bioremediation capacity of the selected seaweed species in the integrated fish-seaweed mariculture system due to the decrease of photosynthetic activity and the simultaneous decrease of ammonium uptake.