• Current Research on Agriculture and Life Sciences
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• v.1
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• pp.179-188
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• 1983

This study was conducted to find out the most fabourable breeding structure for the maximum genetic gain of live weight, the most important economic traits of Korean native cattle, in order to achieve the improvement goals for meat productivity of the native cattle early and effectively. For estimating genetic gain and population mean changes, the following factors were investigated under the assumation that 675,000 heads of over-two-year old cows were maintained each generation and 15% of the cows were culled every year: 1. The proportion of cow population inseminated by A I bulls; 30, 40, 50, 60, 70% 2. The number of semen doses produced from each A I bull per year; 5,000, 7,000, 10,000, 15,000, 20,000 doses. 3. The average body weight of A I bulls; 480, 520, 600, 640, 680, 720kg/18 months of age. The estimated results are summarized as follows: 1. The genetic gain of live weight is affected greately by the levels of A I bulls' body weight and the genetic gain was estimated 28.66~36.31kg per generation. 2. The proportion of genetic gain from sire selection were estimated 80~90%. 3. When the average body weight of A I bulls increase 40kg per generation and more than 50% of cow population is inseminated by A I bulls, then the phenotypic mean value of live weight of bulls at the age of 18 months and heifers at the age of 2 years are expected to be reached 600kg and 520kg in the A I population; 560kg and 480kg in the whole population, respectively, after 5th generation.

• The Korean Journal of Community Living Science
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• v.26 no.3
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• pp.511-522
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• 2015

This study investigates the acute and repeated-dose oral toxicity of crude antifungal compounds produced by Lactobacillus plantarum AF1 (Lb. plantarum AF1) and Lactobacillus plantarum HD1 (Lb. plantarum HD1) in male and female Sprague Dawley rats. In the acute toxicity study, crude antifungal compounds (500, 1,000, and 2,000 mg/kg) did not reduce mortality or produce significant changes in general behaviors or the gross appearance of external and internal organs. In the repeated-dose toxicity study, crude antifungal compounds were administered orally to rats at doses of 500, 1,000, and 2,000 mg/kg daily for 28 days. There were no test-article-related deaths, abnormal clinical signs, or body weight changes. In addition, there were no significant differences between groups treated with crude antifungal compounds and the control group in their organ weight, hematological and serum biochemical parameters, or any other factors. These results suggest that the acute or repeated-dose oral administration of crude antifungal compounds produced by Lb. plantarum AF1 plus Lb. plantarum HD1 is not toxic in male and female rats.

• Elastomers and Composites
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• v.46 no.4
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• pp.304-310
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• 2011

In this study, we prepared poly(ethylene-ter-1-hexene-ter-divinylbenzene) using briged rac-$Et[Ind]_2ZrCl_2$ or unbriged $Cp_2ZrCl_2$ metallocene catalysts. Bridged rac-$Et[Ind]_2ZrCl_2$ catalyst showed relatively good results compared with unbridged one. When cocatalyst/catalyst molar ratio was 3000, catalytic activity indicated more than 8000(kg of polymer/$mol{\cdot}h$) which was very remarkable value. As a polymerization time increased, the weight-average molecular weight of the terpolymer gradually increased to some degree. In the case of a polymerization time of 50 minutes, the state of the terpolymer became amorphous. The range of the weight-average molecular weight and the densities of the terpolymer was 110,000~200,000 and $0.85{\sim}0.89g/cm^3$, respectively. The thermal properties and the structure of the terpolymer were also identified.

• Korean Journal of Organic Agriculture
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• v.19 no.4
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• pp.543-551
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• 2011

This study was conducted to evaluate nutrient production of both orchardgrass and several clovers as a green manure in a 'Niitaka' pear (Pyrus pyriforia) orchard. The experiment was conducted at diligent farmer in Boseong in Chonnam on March 26 of 2010, and the treatments included; 1) orchard grass (2.0kg/$1,000m^2$), 2) orchard grass (1.0kg/$1,000m^2$)+ladino clover (1.0 kg/$1,000m^2$), 3) orchard grass (1.0kg/$1,000m^2$)+red clover (1.0kg/$1,000m^2$), and 4) orchard grass (1.0kg/$1,000m^2$) +white clover (1.0kg/$1,000m^2$). Lengths of orchardgrass and clovers were greater in July than those of June and September. Seeding of orchardgrass without clovers in June and July increased dry weight of green manure crops compared with the seeding of orchardgrass with clovers, resulting in greater annual total dry weight. Various green manure treatments produced different amounts of total N and $P_2O_5$ from each raw materials and did not satisfy amounts of those nutrients for proper annual growth of ten- to twelve-year-old pear tree. Amounts of $K_2O$ producing from green manures, however, satisfied for proper growth of the pear trees.

• Membrane Journal
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• v.20 no.1
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• pp.21-28
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• 2010

Organic/inorganic composite electrolyte membranes were prepared for dye sensitized solar cell (DSSC). Poly (ethylene glycol) (PEG)s with various molecular weight (600, 1,500, 2,000 and 3,400) were ethoxysilated to fabricate organic/inorganic composite materials through sol-gel processes. The electrolyte membranes were produced by doping the composite materials with KI and $I_2$, and their ionic conducting behaviors were investigated. The ionic conductivity of the composite membrane was highly affected by PEG molecular weight. The highest conductivity was shown by the composite membrane prepared with PEG with the molecular weight of 2,000. The composite electrolyte membranes showed considerable improvement of ionic conductivity. Compared to PEO electrolyte membranes, the composite electrolyte membrane by PEG, MW 2,000 showed much higher ionic conductivity.

• Journal of Conservation Science
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• v.32 no.2
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• pp.155-165
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• 2016

This study aimed at verifying the effect of hydroxypropyl cellulose(HPC) treatment on polyethylene glycol(PEG)-treated waterlogged wood for surface stabilizing. This research investigated macroscopic and microscopic appearance, color change, weight change, and dimensional change. And effect of HPC was verified through variance analysis (ANOVA) and least significant difference test(LSD). HPC formed thin layer on the surface of wood specimen, and blocked the pore of tracheid and the gap between the crack. Specimens without deterioration showed no invisible change except HPC 1,000,000 treatment group. Whitening was appeared at the sound surface of HPC 1,000,000 treated wood. Specimens with deterioration showed a little color difference change by external moisture adsorption. Thin layer of HPC on the surface of wood specimen was maintained after the deterioration, and this HPC layer significantly suppressed the weight and dimensional change by moisture adsorption.

• Biomolecules & Therapeutics
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• v.7 no.2
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• pp.185-190
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• 1999

The current study was performed to determine the acute oral toxicity of P55A, a crude extract of 1 : 1 mixture of Phellodendron amurense cortex and Aralia elata cortex, in SD rats and beagle dogs. 5 rats of each sex were treated with a single dose of P55A orally at doses of 0 and 5,000 mg/kg respectively. Also 2 dogs of each sex were treated with a single dose of P55A orally at doses of 0 and 2,000 mgAg, respectively. After the treatment, clinical signs, and body weight change were observed for 14 days. All rats survived during the study and did not show any clinical sign. Body weight gain showed no significant difference between the control and treated rats. Grossly, no lesion was observed in the rats. All dogs survived during the study. In clinical signs, dark stool was observed in the 2,000 mg/kg treated dogs at day 1 after administration. The animals recovered from general signs at day 2 after administration. Body weight gain showed no significant difference between the control and treated dogs. Grossly, no lesion was observed in the dogs. It is suggested that the LD$_{50}$ of P55A by oral administration was estimated to be over 5,000 mg/kg in both sexes of rats and 2,000 mg/kg in both sexes of beagle dogs.s.

• Journal of Environmental Health Sciences
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• v.27 no.3
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• pp.43-48
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• 2001

Terephthalic acid and ethylene glycol resulting form the weight-reduction process of polyester make trouble in the operation of activated sludge process. Also, polyester weight loss wastewater shows high pH, high organic strength and wide variation of organic loading. Therefore, this study was conducted in order to improve treatment efficiency by activated sludge process with Pseudomonas sp degrading components of polyester weight loss wastewater. The CO $D_{Mn}$ and BO $S_{5}$ of the waste wastewater were 560~3,000 mg/$\ell$ and 8000~3,000 mg/$\ell$, respectively. pH was 11.8~12.3. COD removal efficiency by activated sludge-coagulation process with Pseudomonas sp was 94.1~95.8% for 35 hr of hydraulic retention time. Total organic carbon removal efficiency was 97.1%. Ethylene glycol and terephthalic acid in the wastewater were completely degraded during 32 hr of hydraulic retention time.e.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1512-1518
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• 2013

Polycarbonates (PCs) with six different end capping agents were synthesized from melt polymerization. Chemical structure of the synthesized PC was determined by FT-IR spectroscopy. The average molecular weight and distribution, glass transition and thermal degradation temperatures were determined by GPC, DSC and TGA. Average molecular weight changed with the chemical structure of end capping agent, and 4-tert-butylphenol was estimated as the optimum end capping agent. The average molecular weights of PCs decreased with the concentration of the agent, the number average molecular weight was observed as 20,000 - 30,000 when 0.05-0.15 mol% of 4-tert-butylphenol added in PCs. The melt viscosities and glass transition temperature of the PCs decreased with molecular weight. The change for adding method of the agent affected on both the molecular weight distribution and decrease in power law index.

• Environmental Analysis Health and Toxicology
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• v.4 no.3_4
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• pp.77-86
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• 1989

Influences of u-tocopherol on the toxicity of vitamin A acetate in male rats were studied. The obtained results are as follows; 1) The administration of vitamin A acetate 500,000 IU/Kg i.p. twice at 3 days interval decreased the liver weight/body weight and increased the spleen weight/body weight, and increased activities of SGOT and alkaline phosphatase, and also increased BUN and creatinine. 2) ${\alpha}$-Tocopherol administered together with vitamin A acetate as given as the above 1) poteniated the increase of SGOT activity caused by vitamin A acetate and reduced the increase of alkaline phosphatase activity and creatinine which were caused by vitamin A acetate. 3) The administration of vitamin A acetate 500,000 IU/Kg i.p. twice a week for 4 weeks showed remarkable decrease of body weight gain and the effect of it was larger in later stage than in early. It increased significantly liver weight/body weight and further increased the activities of SGOT, SGPT and alkaline phosphatase, and showed no influnence on BUN and creatinine. 4) ${\alpha}$-Tocopherol administered together with vitamin A acetate as given as the above 3) reduced the decrease of body weight gain caused by vitamin A acetate, and potentiated remarkably the increased activities of SGOT and alkaline phosphatase which were caused by vitamin A acetate.