• Asian-Australasian Journal of Animal Sciences
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• v.24 no.8
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• pp.1053-1059
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• 2011

The objective of this study was to assess the teratogenic and embryotoxic effects of clomiphene citrate in mice. The pregnant mice were administered a single dose of clomiphene citrate at different concentrations i.e 1.0, 2.0, 4.0 and 6.0 ${\mu}g/g$ BW on day 8 of gestation. Fetuses recovered on day 18 of gestation were analyzed on morphological, morphometric and histological basis. Morphological observations showed defects like open eyelids, anophthalmia, fore and hindlimb micromelia, meromelia, amelia, sacral hygroma, hydrocephaly, hemorrhagic spots, kyphosis and clubbed feet. Morphometric analysis indicated a significant (p<0.001) reduction in fetal body weight, crown rump length, head circumference, eye circumference, forelimb and hindlimb lengths and tail size against controls. The histological observations showed brain defects like hydrocephaly, enlarged ventricles and undifferentiated neuroglial cells in cerebellum. Cleft palate, underdeveloped pharynx and atrophy of jaw muscles were the common anatomical defects of pharyngeal region. It is concluded that the concentrations of clomiphene citrate used during the present study proved teratogenic in mice fetuses.

• Journal of the Korea Institute of Building Construction
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• v.8 no.4
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• pp.87-93
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• 2008

With an increased use of alternative aggregate due to exhaustion of quality aggregate resources, the amount of used crushed aggregates have been increased and as a result, development of admixture materials has also been improved and its amount of use is increasing from day to day in order to secure quality in concrete. Accordingly, the purpose of this study is to make concrete of good quality by using chemical admixture developed in this study by replacement rate of fine aggregate. At first, susceptibility, compressive strength ratio and length change ratio in both fresh and hardened concrete were evaluated according to corresponding regulation. As for high performance related regulation, APC NO.3 and PC series were going to rule, and as for AE agent regulation, replacement ratio of fine aggregate of high performance chemical admixture was 10:0 and other chemical admixture met quality regulation for AE agent.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.24 no.2
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• pp.35-41
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• 1979

To observe the effects of temperature and photoperiod on the growth and yield of winter wheat (Triticum aestivum, L) eight varieties including Chang Kwang were tested at various treatments like longday-high temperature (24hrs-20\circ), shortdayhigh temperature (12hrs-20\circ), longday-low temperature (24hrs-14\circ) and shortday-low temperature (12hrs-14\circ). Among the traits measured, days to heading, plant height, spike length, number of spikes per hill and grain yield per hill were generally decreased at high temperature and long day treatment and increased at low temperature and shortday condition. Number of grains per spike was decreased at low temperature and short day condition while increased at longday and high temperature conditions. Grain weight was decreased significantly at high temperature and shortday while increased at low temperature and longday treatment.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2000.04a
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• pp.43-50
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• 2000

The flow field of a 1 Ton/Day entrained-flow gasifier constructed in KIER was numerical simulate in this paper. The standard $k-{\varepsilon}$ turbulence model and simple procedure was used with the Primitive-Variable methods during computation. In order to find the influence factors of the flow field which may have great effects on coal gasification process inside gasifier, difference geometry parameters at various operating conditions were studied by simulation methods. The calculation results show that the basic shape of the flow field is still parabolic even the oxygen gas is injected from the off-axis position. There exist an obvious external recirculation zone with a length less than 1.0m and a small internal recirculation region nears the inlet part. The flow field inside the new gasifier is nearly similar as that of the old 0.5T/D gasifier at same position if the design of burner remains unchanged.

• Development and Reproduction
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• v.16 no.1
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• pp.1-8
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• 2012

The reproduction of animals is a way to maintain their species and demands a large amount of energy. The golden hamsters are seasonal breeders whose reproductive activities are regulated by photoperiod (length of day time in a day). The photic information received is transported to the pineal gland via many steps. Melatonin produced by the pineal gland affects the reproductive neuroendocrine system to manage reproductive activities. The major regulator neurons, secreting gonadotropin-releasing hormone, integrate all kinds of information to govern the reproductive frame hypothalamuspituitary-gonad axis. The elements impinging on the neurons are recently outspread. Thus the present review is to briefly survey the elements discovered newly and subjected to the active research realm and their correlations, focusing on the regulation of reproduction in mainly male golden hamsters as a representative animal.

• Child Health Nursing Research
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• v.10 no.3
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• pp.282-290
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• 2004

Purpose: The measure the degree of computer game addiction; to examine the relationship between computer game addiction and contributing factors; and to discover the predictors of computer game addiction of elementary school children of Korea. Method: Data were assembled from questionnaires distributed among 455 children from four elementary schools in Gyung-buk Province. Result: The level of computer game addiction of subjects was rather low, and correlated significantly with gender, academic performance, family economic status, playmates for leisure time, place of playing computer game, length of the habit of playing game, average playing time of game per day, frequency of PC-room(Internet Cafe for game) visits per week, game partners and reasons for playing game. Multiple regression analysis showed that 45％ of the computer game addiction was significantly related to gender(21％), impulsiveness(10％), average playing time of game per day(9％), depression(2％) and other variables(3％) such as playmates for leisure time, academic performance and frequency of PC-room visits per week. Conclusion: We suggest these results be used to develop a computer game addiction prevention program.

• Journal of Practical Agriculture & Fisheries Research
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• v.12 no.1
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• pp.21-27
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• 2010

The objective of this study was to determine the effects of "Green-one" organic nutrient on mycelial growth and fruiting of P. ostreatus. The dilution concentrations of "Green-one" was treated as follows. There was control, 100, 200, 400 concentrations. That treatments were treated with step of each mycelial growth step. The best of growth steps was mycelial scratching step. At that time, DPI(Day required for primordial formation after inoculation) was shortened for 1 day. Valid germination stipe are 15 pieces, 3 pieces more than control. Stipe length and stipe diameter was long each 4mm, 3mm more than control. Pileus size is shortened than control. Yields per one bottle(g/850cc) was 146g increased 6.5% than control 137g/850cc.

• Journal of Bio-Environment Control
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• v.22 no.1
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• pp.43-47
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• 2013

This study was conducted to develop the most effective method in promoting onion set in cultivars 'Josaengsseondebol' and 'Daeji' for all year-round production. This was done by extending the day length for 41 days. For both cultivars, the period to reach the maximum number of leaves developed was shortened as the exposure to day length increased. Between the two cultivars, 'Josaengsseondebol' reaches its maximum leaf formation for a shorter duration compared with 'Daeji'. In effect to bulb size, cultivar 'Josaengsseondebol' having a night break of 1, 2, and 16 hours light condition had better bulb enlargement compared with the non-treated bulbs. In the case of cultivar 'Daeji', only bulbs exposed to a night break of 2 and 16 hours light condition had better bulb enlargement. The percentage of marketable set yield in cultivar 'Josaengsseondebol' having a night break of 1 hr, 2 hrs, 16 hrs light condition, and control or untreated bulbs were 84%, 92%, 90%, and 6% respectively. In the case of cultivar 'Daeji', treated with a night break of 1 hr, 2 hrs, 16 hrs light condition, and untreated bulbs had a percentage marketable set yield of 7%, 55%, 64%, and 0% respectively. Based on these results, it is therefore concluded that night break treatment is considered to be effective method in promoting off-season onion set cultivation in cultivar 'Josaengsseondebol'.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.3
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• pp.241-249
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• 2006

Purpose For the reconstruction of craniofacial deformities, the distraction osteogenesis is an useful method which can make new soft tissues as well as new bone. Although the distraction osteogenesis is an effective procedure in quantitative aspects, the new bone formed by this procedure can be coarse in qualitive aspects sometimes. Materials and methods Twelve rabbits, weighing about 2 kg, were included and the prefabricated distraction device were used. After a latency period of 5 days, in the experimental group (n=6), the mandible was distracted at the rate of 1.0 mm/day for 2 days and then compressed with 1.0 mm for the next 3rd day, therefore distracted totally to a length of 1.0 mm for 3 days. This procedure was repeated 5 times and, as a result, the experimental group was distracted to a length of 5.0 mm for 15 days finally. In the control group (n=6), the mandible was distracted totally to a length of 5.0 mm at the rate of 1 mm/day. At 2 weeks and 8 weeks of consolidation in the control group, 3 rabbits in each group were sacrificed and their biopsy specimens from the distracted mandible were taken. Results All animals showed the mandibular elongation clinically and radiographically. Histologically, many blood vessels, osteoblasts and immature bones formed by osteoid deposition were observed in the experimental group at 2 weeks. At 8 weeks, the bony trabeculae were thicker than the ones in the control group and were composed of lamella bones and woven bones in the experimental group. On histomorphometric analysis, the bone deposition area of the distracted site was broader in the experimental group $(273.8{\pm}115.7\;cm^2)$ than the one in the control group $(199.4{\pm}101.4\;cm^2)$. Futhermore, the modified rate of bone deposition area was higher in the experimental group (48${\pm}$20%) than the one in the control group (35${\pm}$18%). However, these data showed no significant differences statistically. Conclusion These results suggest that the distraction osteogenesis by using an alternating distraction/compression protocols is an effective method for increasing new bone formation in distracted areas.

• Journal of Science Education
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• v.44 no.1
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• pp.1-14
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• 2020

In this study, we analyzed the written and drawn explanations of thirty elementary school pre-service teachers in order to examine their perception on the seasonal length of day and night. The main findings are as follows: First, pre-service teachers used the most common term in the description of the texts, such as meridian altitude, axis of rotation, and revolution, and there were more misconceptions in the drawn explanation than in the written explanation. Second, by analyzing the pre-service teachers' perceptions by combining written and drawn explanations, it is possible to detect scientific errors that the distance between the Earth and the Sun is closer when the axis of rotation is tilted in relation to the revolution and seasonal changes due to changes in the orbital radius of the Earth. In addition, there have been types of explanations such as seasonally changing meridian altitudes related to the rotation of the Earth but no change in the location of the Sun. Based on the results of the analysis, we discussed the lack of experience in constructing an explanatory system of specific phenomena using scientific knowledge, lack of observational experiences about natural phenomena, and lack of exposure to other explanatory systems that cause cognitive conflicts. We hope that it will be concrete and practical help to improve the understanding of pre-service teachers in the science domain of primary teacher training program.