• Environmental Analysis Health and Toxicology
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• v.27
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• pp.5.1-5.10
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• 2012

Objectives: The purpose of this study was to assess the risk of ingestion exposure of lead by particle sizes of crumb rubber in artificial turf filling material with consideration of bioavailability. Methods: This study estimated the ingestion exposure by particle sizes (more than 250 um or less than 250 um) focusing on recyclable ethylene propylene diene monomer crumb rubber being used as artificial turf filling. Analysis on crumb rubber was conducted using body ingestion exposure estimate method in which total content test method, acid extraction method and digestion extraction method are reflected. Bioavailability which is a calibrating factor was reflected in ingestion exposure estimate method and applied in exposure assessment and risk assessment. Two methods using acid extraction and digestion extraction concentration were compared and evaluated. Results: As a result of the ingestion exposure of crumb rubber material, the average lead exposure amount to the digestion extraction result among crumb rubber was calculated to be $1.56{\times}10^{-4}$ mg/kg-day for low grade elementary school students and $4.87{\times}10^{-5}$ mg/kg-day for middle and high school students in 250 um or less particle size, and that to the acid extraction result was higher than the digestion extraction result. Results of digestion extraction and acid extraction showed that the hazard quotient was estimated by about over 2 times more in particle size of lower than 250 um than in higher than 250 um. There was a case of an elementary school student in which the hazard quotient exceeded 0.1. Conclusions: Results of this study confirm that the exposure of lead ingestion and risk level increases as the particle size of crumb rubber gets smaller.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.5
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• pp.728-733
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• 2023

The diet composition of octopus Octopus vulgaris was studied using 392 specimens collected from January to December 2020 in the coastal waters of Yeosu, Korea. The body weight ranged from 86.4 to 3,645.4 g. The most important prey item in the diet of O. vulgaris was decapods, which constituted 43.9% in ranking index (%RI). The second largest prey item was Pisces (%RI=27.9%), and cephalopods (%RI=21.8%) constituted the third largest prey item. The average trophic level of O. vulgaris was 3.97±0.59. Ontogenetic changes were significant among size classes (<400 g, 400-800 g, ≥800 g). The small size class (<400 g) mainly fed on decapods, whereas the medium (400-800 g) and large size (≥800 g) classes mainly fed on cephalopods and Pisces, respectively. The dietary composition varied significantly with season.

• Journal of Biosystems Engineering
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• v.6 no.2
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• pp.65-76
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• 1982

This survey was conducted to investigate the status of repair and maintenance of 4 wheel tractor for a basic reference to the improvement of quality and proper utilization of tractors. Thirty two counties from eight provinces, except Jeju, were covered in this study in order to investigate annual break-down and repair of tractor in 1980. The analyzed results are summarized as follows; 1. The average number of break-down of large size tractors(47ps) was 5.0 times in a year and it was about twice of that of small size tractors(19-23ps). The break-down frequency per 100 hours of use was 1.11 times in the large size and 0.65 times in the small size tractors. 2. 75.6 percent of total break-down was occured in main body of tractor and 24.4 percent in attachments. In particular, the break-down of plow and rotavator was more than 80 percent of total break-down of the small size tractor attachments. 3. The large size tractors which were occured more than one times of break-down a year was 75 percent and its rate of the small size tractor was 62 percent. But 9 percent of tractor surveyed had more than ten times of break-down in a year 4. The frequency of break-down had a peak in May, and it was directly proportional to the hours of use. 5. The causes of break-down were poor maintenance and operation by 29.8 precent, old parts by 30.2 percent, poor quality of parts by 20.6 percent, poor field condition by 16.3 percent and others by 3.1 percent. 6. Annual number of repair was 5.5 times and among them 55.6 percent was done by shop and 44.4 percent by operator. 7. Total required repair time was 30.6 hours a year in the large size tractor and 19.9 hours in the small size tractor. Average repair time was 3.62 hours a time. 8. Annual repair cost was 278 thousand won in the large size tractor and 70 thousand won in the small size tractor. The repair cost per hour of use was 621 won in the large size and 198 won in the small size tractor. 9. The repair cost rate of tractor(Y) was regulated with tractor age (X) as follow; Y=0.752X In case of the service life of tractor was 10 years, the total repair cost rate was 64 percent.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.1
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• pp.74-81
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• 2010

The effects of different levels of natural clay enterosorbent on the growth, nutrient availability, and genital organs of post-weaning female pigs fed with an addition of zearalenone (ZEA) were investigated in the study. A total of thirty-five post-weaning gilts ($L{\times}Y{\times}D$) with an average body weight of 12.36${\pm}$1.46 kg were used in the test. The gilts were raised individually in metabolism cages and fed a corn-soybean meal-whey basal diet with an addition of 0 or 1 mg/kg of ZEA for 24 d with four levels of natural clay enterosorbent added in the feed. The treatments were: i) control; ii) control+2.5 g/kg clay; iii) control+1 mg/kg ZEA; iv) control+1 mg/kg ZEA+1.25 g/kg clay; v) control+1 mg/kg ZEA+2.5 g/kg clay; vi) control+1 mg/kg ZEA+5.0 g/kg clay; vii) control+1 mg/kg ZEA +10 g/kg clay. Pigs fed diets contaminated with additional purified ZEA had significantly reduced apparent digestibility of crude protein (CP), gross energy (GE) and apparent metabolic rate of GE (ME/GE, p<0.05) without changes of net protein utilization (NPU, p>0.05). Final body weight, average daily gain (ADG), average daily feed intake (ADFI), vulva length, vulva width, vulva area, relative weights of genital organ and proliferative changes of the ovary tissues in gilts fed ZEA-contaminated diet were increased (p<0.05) compared to the gilts fed the control diet. Addition of natural clay enterosorbent in the ZEA-contaminated diet showed a positive protection effect on ZEA feeding, and the protection was increased linearly or quadratically as clay content increased. However, in pigs fed a diet with clay alone at 2.5 g/kg level there was no significant impact (p>0.05) on all the parameters as compared to the control. It is suggested that feeding ZEA at about 1.0 mg/kg for 24 days might result in a deleterious effect in pigs, and addition of 5 or 10 g clay enterosorbent per kg diet can effectively neutralize the detrimental effects of the ZEA feeding.

• Journal of Chest Surgery
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• v.33 no.9
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• pp.716-722
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• 2000

Background: Modified Blalock-Taussig shunt using 3mm or 3.5mm PTFE graft has been performed in patients with small body weight or in candidates for single ventricle palliation. However, there are few reports concerning clinical outcomes in terms of pulmonary artery growth and shunt patency rate after shunt operations using such a small graft. Material and Method: Twenty-five patients rate after shunt operations using 3 or 3.5 mm sized grafts from September 1996 to August 1999. We retrospectively assessed the pulmonary artery growth and the shunt patency rate by reviewing the pre-and post-operative pulmonary angiograms. The risk factors for late death and second shunt operations were also analyzed. To assess the presence of any correlation between body weight and selection of the graft size, regression analysis was done in 81 cases of shunt operations performed during the same period. Result: There were 1(4%) early death and 5(20%) late deaths. The survivors were followed up for an average of 7.34 months. The pulmonary artery index increased significantly from 129$\pm$66$\textrm{mm}^2$/$m^2$ to 213$\pm$114 $\textrm{mm}^2$/$m^2$(p=0.002). The shunt patency rate assessed at postoperative 2, 4, 6 and 8 months were 82.5%, 77%, 73% and 42% respectively with a marked decline between 6 and 8 months. Asplenia was a frequent finding for the patients with late death although the incidence failed to reach statistical significance(p=0.078). Pre-operative diagnosis of PA with VSD was found to be a statistically significant risk factor for a second shunt operation(p=0.01). Body weight(a) at operation and graft size(b) used in the shunt operations revealed strong correlation and could be expressed by the following formula; b=0.128a + 3.233. Conclusion: Adequate growth of pulmonary artery and satisfactory early patency rate could be obtained by modified Blalock-Taussing shunt using 3mm or 3.5mm graft. However, during 6 to 8 months after shunt operations, the patency rate fell sharply, which implicates that close observation and early intervention are mandatory in this period.

• Korean Journal of Ichthyology
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• v.13 no.2
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• pp.93-99
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• 2001

Skin mucous cells in the three regions of the body in Pseudobagrus fulvidaraco and Leiocassius nitidus were investigated using three histochemical methods (PAS, AB-PAS and HID). In the two species, components of mucous cell were not distinguished in each region, but presented a differences in position and type, size, and count in all regions. Mucous cells of P. fulvidraco were located in two layers, a superficial epithelial cell and the space within alarm substance cells (ASCs). Mucous cells of L. nitidus were situated only in the superficial epithelial cell layer. The size of mucous cells in the ASC layer were larger than those of the superficial epithelial cells for all measured values: diameter, length, width, and area. In the superficial epithelial cell layer, the average number of mucous cells within the three regions did not differ significantly between species by unpaired T-test, but the average number of those within two cell layers of P. fulvidraco had a similarity at each region by paired T-test. The dismilarity in dorsal and ventral regions in average number of ASCs between P. fulvidraco and L. niditus was confirmed by unpaired T-test.

• Journal of Animal Environmental Science
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• v.15 no.2
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• pp.139-146
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• 2009

This study was carried out to investigate the reproductive and weaned performances in sow farms, which located in Boryeong city, Chungnam. Data surveyed a total of 10,394 litters of sow recorded from April, 2007 to March, 2008 were collected and analyzed. The results obtained were as follows; 1. The average of number of sow and farrowing rate were 314.10 sows and 78.77%, respectively. And then, there was not significant difference among seasons in number of sows, but significant difference among season was found in farrowing rate (p<0.05). 2. The average of litter size at farrowing and at initial sucking were 11.04 and 10.22 pigs, respectively. The significant differences were not all found in litter size among seasons. 3. The number of pigs, age and growth rate at weaning were 9.23 pigs, 25.77 days and 91.48%, respectively. The significant differences among seasons were not found in number of pigs and age at weaning. However, there was significant difference in growth rate at weaning (P<0.05). 4. The average of farrowing rate of sows per year, pigs from sow per year (PSY), and body weight at marketing were 2.25 times, 20.75 pigs, and 110.46 kg, respectively. The significant differences among seasons were not found in farrowing rate per year and weight at marketing, but that was found only in PSY (p<0.05), respectively.

• Korean Journal of Ichthyology
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• v.35 no.3
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• pp.177-182
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• 2023

Total 158 Conger myriaster were examined and the range of Preanal length (PaL) was 8.2~40.1 cm and average Preanal length was 17.3 cm. Proportion of the empty stomach was 30.4% and individuals, which the prey items were found in stomach, were 110. The most important prey component in the diets of C. myriaster was Pisces that constituted 54.4% in %IRI (Index of relative importance). Engraulis japonicus was the most important prey component in Pisces. Macrura was the second largest prey component and Crangon hakodatei was the most important prey component in Macrura. The result of analysis in ontogenetic changes significantly exhibited among three size classes (<15.0 cm, 15.0~20.0 cm, ≥20.0 cm). The proportion of Macrura decreased as increasing body size, whereas the consumption of Pisces increased gradually. As body size of C. myriaster increased, the mean weight of prey per stomach (mW/ST) increased (one way-ANOVA, P<0.05).

• Korean Journal of Environment and Ecology
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• v.28 no.3
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• pp.281-286
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• 2014

This study was conducted to investigate the individual size and age of Kaloula borealis, a pair in amplexus. In June 2013, the total 23 pairs of Kaloula borealis were captured in the wetland located in Seongsan-eup and Daejeong-eup, Jeju Island. Size and age of each individual have been examined and as a result of analyzing SVL (snout-vent length), weight, length of forelimb and hindlimb of the collected 23 pairs, the females were shown to have the heavier weight and the longer SVL and hindlimb compared to males. No significant difference in the length of forelimb has been found between the female and the male. The average age of the male of the pair in amplexus was shown to be $5.17{\pm}0.26$, whereas the female was shown to be $6.22{\pm}0.28$, which indicates the higher average age in female compared to the male. The age range of Kaloula borealis was distributed from at least 3 years to 10 years at the maximum. A positive correlation was shown between age of the male and SVL; however, no significant difference was found in female. This study result expected to be utilized as an important base data in establishing the preservation and restoration strategy of endangered species, Kaloula borealis.

• Journal of the Korean Ceramic Society
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• v.39 no.10
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• pp.994-1000
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• 2002

Oxygen permeability and the mechanical properties of mixed ionic-electronic conductive $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_{3-{\delta}}$ perovskite-type membrane, fabricated by solid state reaction, were investigated with regard to microstructure. The microstructure of the membrane was controlled by changing the sintering temperature and holding time. The average grain size and relative density were evaluated as a function of sintering conditions. As the fraction of grain boundary decreased, oxygen permeability showed a tendency to increase. Especially the maximum oxygen flux of 0.37 ml/$cm^2$${\cdot}$min was measured for the specimen sintered at 1300${\circ}C$ for 10 h, which has high density and relatively large grain size. Fracture strength was dependent on the relative density of sintered body, while fracture toughness increased with average grain size.