• Clinical and Experimental Reproductive Medicine
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• v.40 no.2
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• pp.83-89
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• 2013

Objective: To investigate outcomes of stimulated IVF cycles in which GnRH antagonist was omitted on the ovulation triggering day. Methods: A total of 86 women who underwent controlled ovarian hyperstimulation with recombinant FSH and GnRH antagonist flexible multiple-dose protocols were recruited and prospectively randomized into the conventional group (group A) or cessation group (group B). The GnRH antagonist, 0.25 mg/day of cetrorelix, was started when the leading follicle reached 14 mm in diameter and was continuously administered until the hCG triggering day (group A, 43 cycles) or until the day before hCG administration (group B, 43 cycles). The maturity of oocytes, fertilization rate, embryo quality, and implantation and clinical pregnancy rates were evaluated. Results: The duration of ovarian stimulation, total dose of gonadotropins, serum estradiol levels on hCG administration day, and number of oocytes retrieved were not significantly different between the two groups. The total dose of GnRH antagonist was significantly lower in group B than group A ($2.5{\pm}0.9$ vs. $3.2{\pm}0.8$ ampoules, p<0.05). There was no premature luteinization in any of the subjects. The proportion of mature oocytes and fertilization rate were not significantly different in group B than group A (70.7% vs. 66.7%; 71.1% vs. 66.4%, respectively). There were no significant differences in the implantation or clinical pregnancy rates. Conclusion: Our prospective randomized study suggested that cessation of GnRH antagonist on the hCG administration day during a flexible multiple-dose protocol could reduce the total dose of GnRH antagonist without compromising its effects on pregnancy rates.

• Journal of Animal Science and Technology
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• v.65 no.4
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• pp.759-766
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• 2023

Visual estrus observation can only be confirmed at a rate of 50%-60%, which is lower than that obtained using a biosensor. Thus, the use of biosensors provides more opportunities for artificial insemination because it is easier to confirm estrus than by visual observation. This study determines the accuracy of estrus prediction using a ruminoreticular biosensor by analyzing ruminoreticular temperature during the estrus cycle and measuring changes in body activity. One hundred and twenty-five Hanwoo cows (64 with a ruminal biosensor in the test group and 61 without biosensors in the control group) were studied. Ruminoreticular temperatures and body activities were measured every 10 min. The first service of artificial insemination used gonadotropin-releasing hormone (GnRH)-based fixed-time artificial insemination protocol in the control and test groups. The test group received artificial insemination based on the estrus prediction made by the biosensor, and the control group received artificial insemination according to visual estrus observation. Before artificial insemination, the ruminoreticular temperature was maintained at an average of 38.95 ± 0.05℃ for 13 h (-21 to -9 h), 0.73℃ higher than the average temperature observed at -48 h (38.22 ± 0.06℃). The body activity, measured using an indwelling 3-axis accelerometer, averaged 1502.57 ± 27.35 for approximately 21 h from -4 to -24 h before artificial insemination, showing 203 indexes higher body activity than -48 hours (1299 ± 9.72). Therefore, using an information and communication techonology (ICT)-based biosensor is highly effective because it can reduce the reproductive cost of a farm by accurately detecting estrus and increasing the rate of estrus confirmation in cattle.

• Korean Journal of Environmental Agriculture
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• v.19 no.3
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• pp.191-193
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• 2000

To find out the countermeasure to plant damage at soil contaminated with oil, several adsorbents such as muck, peat, sawdust and PEAT SORB were treated at diesel oil contaminated soil. As the results, sawdust and PEAT SORB showed better effect of oil adsorption than muck and peat. Removal rate of diesel oil with sawdust treatment was higher than 95% at the condition which the ratio of adsorbent amount to oil was higher than 1:2(w/v). And the releasing amount of oil from adsorbent-oil complex was very small. With the oil treatment of $4,000\;L{\cdot}ha^{-1}$ at tillering stage, rice plant height and chlorophyll content were lower than control at non-adsorbent treatment, but those were increased at sawdust treatment.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.14 no.4
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• pp.225-247
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• 2010

In this paper, we establish a two-competitive-prey and one-predator Holling type II system by introducing a proportional periodic impulsive harvesting for all species and a constant periodic releasing, or immigrating, for the predator at different fixed time. We show the boundedness of the system and find conditions for the local and global stabilities of two-prey-free periodic solutions by using Floquet theory for the impulsive differential equation, small amplitude perturbation skills and comparison techniques. Also, we prove that the system is permanent under some conditions and give sufficient conditions under which one of the two preys is extinct and the remaining two species are permanent. In addition, we take account of the system with seasonality as a periodic forcing term in the intrinsic growth rate of prey population and then find conditions for the stability of the two-prey-free periodic solutions and for the permanence of this system. We discuss the complex dynamical aspects of these systems via bifurcation diagrams.

• The Korean Journal of Malacology
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• v.32 no.2
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• pp.67-71
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• 2016

In order to obtain a large number of fertilized eggs for seedling production, experiment was carried out examine effects of serotonin on spawning of the Pacific oyster Crassostrea gigas. The shorter response time to initial spawning in case of serotonin injection showed, the higher serotonin injected with 7.6-27 min. The response time to initial sperm releasing showed the same tendency with female. The highest response rates and eggs amount spawned were showed in the highest concentration. The serotonin injection had no effect on frequency of germinal vesicle breakdown (GVBD), fertilization and hatching rate.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.503-506
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• 2015

Ever since Samsung Electronics has released its first Galaxy Note series, it has been releasing a new different Galaxy model every year and now Galaxy Note 4 has been released in 2015. The consumers' interest in 'Phablet' has been growing since the release of Galaxy Note 1, and the market share rate for Phablet, which was only about 2 % out of the entire mobile phone market in 2013, has grown to 10% within just a year. This thesis analyzed the response of consumers about the Phablet, and expected the future of the Phablet market. Consumer behavior analysis was conducted through a questionnaire.

• Journal of the Korean Chemical Society
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• v.17 no.3
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• pp.198-206
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• 1973

We produced the glass beads using a spherical vessel which is rotable with the mix ture of releasing agent and glass powder in a electric furnace (apparatus 1), a tubing apparatus of electric furnace which can be gravitated a cullet (apparatus 2) and a tubing apparatus which is dispersible glass powders with the flame of propane gas (apparatus 3). The substrates which are Korean sodium silicates glass 1, 2, boro silicates glass and lead silicates glass are used and the size of cullets is 60-300 mesh. In the results of experimental apparatus, the preferable temperature of apparatus 1 is 880$^{\circ}C$, apparatus 2 is 980$^{\circ}C$ and apparatus 3 is 1100$^{\circ}C$. However, the method of apparatus 3 is more effective than the methods of apparatus 1 and 2 in view of treating time and rate of adhesion.

• Journal of Environmental Science International
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• v.11 no.12
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• pp.1261-1265
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• 2002

This study was focused on the investigation of the characteristics of organics and nitrogen removal with the recycle ratio in anoxic/oxic(A/O) packed bed process that consisted of the anoxic reactor and the aerobic reactor. As increasing the recycle ratio by 0.5, 1.0, 2.0, the COD removal efficiency increased by 94.0%, 98.5%, 98.8% respectively. The aerobic reactor showed the perfect nitrification efficiency by 98.5%, 99.2%, 98.0% respectively. The T-N removal efficiency with the recycle ratio, increased by 56%, 67%, 70% respectively. As increasing the recycle ratio by 0.5, 1.0, 2.0, T-P removal efficiency decreased by 62.1%, 57.4%, 51.3% respectively. The process by releasing the stored phosphorus in the anoxic reactor and uptaking the excess phosphorus in the aerobic reactor, occurred well comparatively when recycle ratio is 0.5. But this process did not occur when the recycle ratio is 1.0 and 2.0. And optimum pH of nitrification was about 6~7 and alkalinity decreased as nitrification rate increased. As increasing the recycle ratio in the anoxic reactor, DO concentration and ORP increased.

• Progress in Superconductivity and Cryogenics
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• v.18 no.1
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• pp.28-32
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• 2016

There are a few thousand abandoned metal mines in South Korea. The abandoned mines cause several environmental problems including releasing acid mine drainage (AMD), which contain a very high acidity and heavy metal ions such as Fe, Cu, Cd, Pb, and As. Iron oxides can be formed from the AMD by increasing the solution pH and inducing precipitation. Current study focused on the formation of iron oxide in an AMD and used the oxide for adsorption of heavy metals. The heavy metal adsorbed iron oxide was separated with a superconducting magnet. The duration of iron oxide formation affected on the type of mineral and the degree of magnetization. The removal rate of heavy metal by the adsorption process with the formed iron oxide was highly dependent on the type of iron oxide and the solution pH. A high gradient magnetic separation (HGMS) system successfully separated the iron oxide and harmful heavy metals.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.3
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• pp.409-416
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• 2003

This study was carried out to find a cholesterol removal rate, flavor development and bitter amino acid productions in Cheddar cheese treated with $\beta$-cyclodextrin (CD): 1) Control (no homogenization, no $\beta$-CD), and 2) Milk treatment (1000 psi milk homogenization, 1% $\beta$-CD). The cholesterol removal of the cheese was 79.3%. The production of short-chain free fatty acids (FFA) increased with a ripening time in both control and milk treated cheese. The releasing quantity of short-chain FFA was higher in milk treated cheese than control at 5 and 7 mo ripening. Not much difference was found in neutral volatile compound production between samples. In bitter-tasted amino acids, milk treatment group produced much higher than control. In sensory analysis, texture score of control Cheddar cheese significantly increased with ripening time, however, that in cholesterol-reduced cheese decreased dramatically. Our results indicated that the cheese made by $\beta$-CD treated milk with low pressure homogenization showed an effective cholesterol reduction and a rapid cheese ripening, while no capture of flavor compounds by $\beta$-CD.