• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6A
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• pp.535-542
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• 2010

Precise estimation of a structure's dynamic characteristics is indispensable for ensuring stable dynamic responses during lifetime especially for the structures which can experience resonance such as railway bridges. In this paper, the results of forced vibration tests of different excitation methods (vibration exciter and impact hammer) are compared to examine the differences and the cause of differences of extracted natural frequencies. Consequently a natural frequency modification method is suggested to eliminate effects of non-structural disturbance factors. Also, sequential forced vibration tests are performed before and after track construction according to the construction stage of a railway bridge, and the variation of natural frequencies are examined. Effect of added mass of vibration exciter and variation of support condition due to the level of excitation force are concluded as the major cause of natural frequency differences. Thus eliminating these effects can enhance the reliability of the extracted natural frequencies. Construction of track affects not only the mass of structure but also the stiffness of the structure. Also, the amount of increase in stiffness varies according to the level of structural deflection. Therefore, reasonable estimation of the level of structural response during operation is important for precise natural frequency calculation at design phase.

• Journal of Life Science
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• v.17 no.4 s.84
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• pp.529-534
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• 2007

The effects of dietary eggs on liver and serum lipids, serum protein and mineral concentrations, and enzyme activities in male rats were studied. Sprague-Dawley rats were fed four types of diets for 4 weeks, respectively: a control diet, a control diet supplemented with 5, 10 or 15% eggs powder. In rats fed 5, 10 or 15% egg diets the body weight gain, the food intake, the weights of kidney and epididymal fat pad were similar to those in rats fed the control diet. The hepatic weight, hepatic cholesterol and triglyceride concentrations of rats fed the all egg diets were significantly higher than those of rats fed the control diet. The concentrations of total cholesterol, HDL-cholesterol, LDL+VLDL-cholesterol, triglyceride and phospholipid in the serum of rats fed the all egg diets were similar to those of rats fed the control diet. In the rats fed 5% egg diet the HDL-cholesterol/total-cholesterol ratios was significantly increased, and the atherogenic index was significantly decreased compared with those in the rats fed 10 or 15% egg diets. The serum total protein and albumin concentrations of rats fed 10 or 15% egg diets were significantly increased compared with those of rats fed the control diet. The serum calcium levels of rats fed the all egg diets were significantly increased compared with those of rats fed the control diet. No differences were noted in the concentrations of urea nitrogen, creatinine, glucose and hemoglobin, and activities of GOT, GPT, ${\gamma}-GTP$ and alkaline phosphatase in the serum among the rats with on all the experimental diets. These results showed that the all egg diets feeding increased cholesterol and triglyceride concentrations in liver, but no differences lipids and lipoprotein cholesterol concentrations in serum of rats.

• Journal of Life Science
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• v.16 no.6
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• pp.932-937
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• 2006

The effects of cheonggukjang (CK) on the weight gains, serum and hepatic lipids levels were investigated in adult female rats fed the cholesterol diets. Sprague-Dawley strain rats were given four different types of diet for 4 weeks, respectively: a normal diet, a control diet (10% fat + 0.5% cholesterol), a 5% or 10% CK diets (control diet + 5% or 10% CK powder). The body weights, food intake and food efficiency ratios, and the uterine fat pad weights of 5% CK and 10% CK groups were more significantly decreased than those of the control group. The liver cholesterol and triglyceride levels were significantly lower of the 10% CK group than those of the control group. The concentrations of serum triglyceride, total cholesterol, LDL+VLDL-cholesterol, and atherogenic index ratios were significantly decreased in the 10% CK group compared with those in the control group. The HDL-cholesterol/total-cholesterol ratios was significantly increased in the 10% CK group compared with those in the control group. The fecal total lipid excretion of the 5% and 10% CK groups were more increased than those in the control group. These results showed that the 10% cheonggukjang feeding decreased the triglyceride, total cholesterol, LDL+VLDL-cholesterol and atherogenic index ratios in serum as well as the triglyceride and cholesterol in liver, and increased the HDL-cholesterol/total-cholesterol ratio in serum.

• Journal of Life Science
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• v.16 no.7 s.80
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• pp.1127-1132
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• 2006

Effects of dietary supplementation of Pleurotus eryngii(PE) to a diet containig the cholesterol on lipid levels in the liver and serum, and enzyme activities of rats were studied by feeding 8-weeks old male rats with the four diets for 4 weeks, respectively: normal diet, control diet (10% fat + 0.5% cholesterol), 3% and 5% PE diets (control diet + 3% and 5% PE dry powder). The body weight gains and food efficiency ratios of the 3% and 5% PE diet groups were significantly lower than those of the control group. The liver and epididymal fat pad weights, and hepatic triglyceride Levels of the 5% PE diet group were more significantly decreased than those of the control group. The concentrations in serum triglyceride, total cholesterol, LDL+VLDL-cholesterol, and atherogenic index ratios were significantly lower in the 3% or 5% PE groups compared to those of the control group. Ratio of HDL-cholesterol to total-cholesterol was significantly higher in the 3% and 5% PE groups compared to that of the control group. The fecal total lipid excretion of the 5% PE diet group was more significantly decreased than that of the control group. There was no significant difference in the hepatic cholesterol, and the serum HDL-cholesterol concentrations, and the GOT, GPT and ${\gamma}-GTP$ activities among the experimental groups. These results showed that the Pleurotus eryngii powder feeding decreased the total cholesterol, LDL-cholesterol and atherogenic index, and increased the ratio of HDL-cholesterol to total-cholesterol in serum of the rats.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.5
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• pp.821-826
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• 2004

The effects of the fruiting body of Agaricus blazei Murill on the weight gains, food intakes, food efficiency ratios, serum and hepatic lipids concentrations were investigated in male rats. Sprague-Dawley rats, 21 weeks old, were given four different types of diets for a succeeding period of 10 weeks: either a normal diet (5% corn oil), a high fat diet (high fat; 20% lard), a 3% or 5% Agaricus diet (high fat diet+3% or 5% Agaricus powder). The body weight gains and food efficiency ratios of the rats fed 5% Agaricus diet were significantly lower than those of the rats fed high fat diet. The hepatic and kidney weights of the rats fed Agaricus diets were similar to those of the rats fed high fat diet. The epididymal fat pad weights of the rats fed 3% or 5% Agaricus diets were significantly lower than those of the rats fed high fat diet. The concentrations of hepatic and serum triglyceride in the rats fed 5% Agaricus diet were significantly lower than those in the rats fed high fat diet. But the hepatic total cholesterol of rats fed the 3% or 5% Agaricus diets were similar to those of rats fed the high fat diet. The concentrations of serum total cholesterol, LDL-cholesterol and atherogenic index in rats fed the 3% or 5% Agaricus diets were significantly decreased compared with those of rats fed the high fat diet. The HDL-cholesterol/total- cholesterol ratios of the rat fed 3% or 5% Agaricus diet were significantly increased compared with those of rats fed the high fat diet. There were no differences in serum concentrations of HDL-cholesterol and phospholipid among the experimental groups. These results showed that the 5% Agaricus diet feeding decreased the total cholesterol, the triglyceride, the LDL-cholesterol and the atherogenic index, and increased the HDL-cholesterol/total-cholesterol ratio in serum of rats.

• Journal of Life Science
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• v.15 no.3 s.70
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• pp.479-485
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• 2005

The 994 throat swabs obtained from 688 adults and 306 children patients with respiratory diseases were examined for Mycoplasma pneumoniae infection by culture method. Antimicrobial susceptibilities of the resulting 123 M. pneumoniae isolates were evaluated by testing minimum inhibitory concentrations (MICs) of erythromycin, minocycline, tetracycline, josamycin, sparfloxacin, ofloxacin, and ciprofloxacin by a broth micro-dilution method. The erythromycin resistant strains of M. pneumoniae was determined above $1.0{\mu}g/ml$ of MIC for erythromycin. The erythromycin resistant strains of M. pneumoniae was confirmed resistant gene mutation of the portions of genes 23S rRNA (domain II and V), and ribosomal protein 14 and L22 by PCR amplified and their nucleotide sequenses were compared to those of the susceptible strain M129. The isolation rate of M. pneumoniae was $12.9\%$ (89/688) for the adults and $11.1\%$ (34/306) for the children. The $MICs_{90}$ of the M. pneumoniae isolates were $0.12{\mu}g/ml$ for minocycline, $0.25{\mu}g/ml$ for sparfloxacin, $0.5{\mu}g/ml$ for ciprofloxacin, ofloxacin, and tetracycline, respectively, and $2.0{\mu}g/ml$ for josamycin and erythromycin, respectively. The isolation rate of erythromycin resistant M. pneumoniae from patients was $49.4\%\;(44/89)$ for the adults, $47.1\%\;(16/34)$ for children, and $48.8\%\;(60/123)$ for the total. No mutation could be detected in the ribosomal protein L22 region, but all strains were mutated in the ribosomal protein L4 as two point mutation M144V. Two point mutations in domain V of 23S rRNA were selected in the presense of erythromycin resistant M. pneumoniae isolates, such as one strain was G2057C mutant, two strains were A2059C mutants, three strains were C2611G mutants, four strains were A2058C mutants, five strains were A2058T mutants, twenty strains were A2059G mutants, and twenty-five strains were A2058G mutants, respectively. These results show that erythromycin was not the most active compound against M. pneumoniae infection in Korea and clinical studies of macrolides in human patients are demanded.