• Journal of Animal Science and Technology
• /
• v.54 no.3
• /
• pp.165-174
• /
• 2012

For horse breeders or managers, it is critical to understand the estrous cycle of mares. Breeding of mares cannot be successfully achieved throughout the whole year as mares breed seasonally. Mares are only able to breed when day length is more than 16 h, and this period is known as the breeding season. Their estrous cycle is approximately 21 days with 5-7 days of estrus and 14 to 15 days of a diestrus period. The estrous cycle of the mare is mainly controlled by gonadotropins, which control follicular development and ovulation. Mares exhibit unique ovulatory events which are not observed in other species. A LH surge occurs for several days, with levels of LH reaching their peak after ovulation. The LH level at the time of LH peak is lower than most other species. The unique anatomical structure of the ovaries of mares is known to limit the number of eggs ovulated. Several attempts have been made to develop chemical/hormonal agents which might be used to manipulate the timed ovulation of mares. Agents that have been tested include hCG, native GnRH, Deslorelin (Ovuplant, GnRH-agonist), Buserelin (GnRH analogue), equine pituitary extracts and equine chorionic gonadotropin (eCG or PMSG). However, the function, purity or stability of these agents is not reliable. Recombinant equine LH, an alternative agent for the timed ovulation, has been developed and tested for its biological activities, through the use of both in vitro and in vivo experiments. The reLH was suggested to be a reliable agent in inducing ovulation within 48 h after being administered through injection, when the size of dominant follicle is 35 mm in diameter.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.40 no.4
• /
• pp.346-353
• /
• 2012

The Laser-Induced Breakdown Spectroscopy (LIBS) has great advantages as an analytical technique, namely real-time analysis without sample preparation, ideal for mobile chemical sensor for space exploration. The LIBS plasma characteristics are strongly dependent on the surrounding pressure. In this study, seven types of target (C, Ti, Ni, Cu, Sn, Al, Zn) were investigated for their elemental lifetime. The target was located in vacuum chamber which has the pressure range of 760 to $10^{-5}$ torr. As the pressure is decreased, the elemental lifetimes of carbon and titanium declined, while all other targets showed increased lifetimes until reaching 1 torr and declined with continued pressure decrease. The boiling point and electronegativity amongst the physicochemical properties of the samples are used to explain this peculiarity.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.22 no.4
• /
• pp.108-113
• /
• 2018

Researches on strengthening and rehabilitation methods are being widely conducted due to the deterioration of existing concrete structures. Use of externally bonded Carbon Fiber Reinforced Polymers (CFRP) strips for the rehabilitation is a cost-effective and time-saving method. Generally, the CFRP layout for the shear strengthening was a uni-directional layout. Many researches have focused on the variables of the uni-directional CFRP layout such as the amount of material, angle, and spacing. Pilot tests indicated that the effective confinement of the concrete member can be provided with the bi-directional CFRP layout than the uni-directional layout. Therefore, the test was carried out after the uni- and bi-directional strengthening work using the same amount of CFRP material. CFRP anchors were installed to prevent unexpected premature CFRP delamination failure before reaching CFRP fracture strain. The effectiveness of the CFRP anchor and bi-directional CFRP layout for shear strengthening was verified based on the principal tensile strain contours.

• The Journal of the Korea Contents Association
• /
• v.8 no.8
• /
• pp.244-252
• /
• 2008

This research differentiate the technique of Jungkwon-jirugi, one of the basic movements of Taekwondo, into two movements stop-jirugi and push-jirugi and gives analysis of the impulse, acceleration and velocity in the point of motor control. For this, we tried graphic analysis using an acceleration sensor and high speed camera which was made from USA in 2005 and took pictures at 250 frames per second. We reached the following conclusions. First, the acceleration wave of push-jirugi was a period longer than stop-jirugi, meaning that the push-jirugi motion asserts force for a longer time. Second, the acceleration and velocity graph shows that the highest velocity occurs on the point when the acceleration begins to decrease right after reaching its maximum. Third, according to the image analysis using the high speed camera, we could find out that the shoulder is pushed a little even in the stop-jirugi motion.

• Korean Journal of Construction Engineering and Management
• /
• v.9 no.5
• /
• pp.95-103
• /
• 2008

In recent years, there has been more reconstruction and redevelopment of apartments rather than efforts to consider alternative to extend the life time oh the apartments. It is essential to try to develop ways to adequately maintain and to use the apartment facilities efficiently in order to preserve earth environment and the limited resource. However, lacking research on the effects obtained through remodelling and maintenance have interfered with the vitalizing of the market. The objective of this study is to propose criterions and methods with which to evaluate adequacy of developing method. A survey was performed to investigate important evaluating methods in order to obtain advices that can smoothly progress improve apartment developing method. This study applied AHP(Analytical Hierarchy Process) methods for reasonable dependancy of developing in apartment. Through this study, the flow of apartment market is elevated to reaching the level in advanced nation.

• Nuclear Engineering and Technology
• /
• v.51 no.8
• /
• pp.1964-1969
• /
• 2019

The safety and efficiency of nuclear reactors largely depend on the monitoring and control of nuclear radiation. Due to the unique nuclear-physical characteristics, Hf is one of the most promising materials for the manufacturing of the control rods and the emitters of neutron detectors. It is proposed to use the Compton neutron detector with the emitter made of Hf in the In-core Instrumentation System (ICIS) for monitoring the neutron field. The main advantages of such a detector in comparison the conventional β-emission sensors are the possibility of reaching of a higher cumulative radiation dose and the absence of signal delays. The response time of the detection is extremely important when a nuclear reactor is operating near its critical operational parameters. Taking Hf as an example, the general principles for calculating the chains of materials transformation under neutron irradiation are reported. The influence of ^179m1Hf on the Hf composition changing dynamics and the process of transmutants' (Ta, W) generation were determined. The effect of these processes on the absorbing properties of Hf, which inevitably predetermine the lifetime of the detector and its ability to generate a signal, is estimated.

• The Journal of Pediatrics of Korean Medicine
• /
• v.21 no.1
• /
• pp.253-270
• /
• 2007

Objectives : This study has been carried out to understand the effect of Cimicifugae Rhizoma and Seungmagalgeuntang on the hyperglycemic mice induced with Streptozotocin(STZ). Methods : The 60mg/kg of STZ was fed into mice twice by 24 h interval and then 120mg/kg STZ was fed again 3 days after the earlier feeding, Control group was administered mice with 0.9% saline(2mL/kg/day), and experimental groups were administered Cimicifugae Rhizoma extract(CA group, 10mg/kg/day; CB group, 30mg/kg/day) or Seungmagalgeuntang(SA group, 10mg/kg/day; SB group, 30mg/kg/day) after hyperglycemic induction for 6 weeks. Results : The body weight of experimental groups higher than control. The blood glucose concentration of the control group increased continuously reaching to 298.9 mg/dL after 6 weeks, however, significantly(p<0.01 or p<0.05) decreased in the SA and SB groups compared with control group. Blood insulin level significantly(p<0.01) increased in the experimental groups. The activities of SOD and catalase were more decreased in the experimental group than control group compared with normal group. In the point of pancreatic immunohistochemical change, the experimental group's pancreatic islets have increased and enlarged and the concentration of insulin-positive beta cells has also increased, comparing with the control group. Meanwhile forms of nucleus and mitochondria in the experimental group's hepatic cells were almost similar to the normal group. Conclusion : The result from the six weeks of observation demonstrates that the extracts from Cimicifugae Rhizoma and Seungmagalgeuntang have positive effects on lowering blood sugar level and elevating insulin concentration. The extract had also effects on recovering and regenerating pancreatic tissue of the hyperglycemic mice induced with STZ. At the same time, it had a protective effect against hepatotoxicity as well.

• Journal of Conservation Science
• /
• v.26 no.4
• /
• pp.459-465
• /
• 2010

The 5th century kiln that produced pottery coffins was found for the first time in Korea, located in the Oryang-dong remains in the city of Naju. This kiln, located in the central area of the Yeongsan River, provides important data for research on mortuary practices in prehistoric society, including the structure of production and patterns of distribution and consumption. For this study, the remains of five ancient tombs and pottery coffins excavated from the 4th century Mandong archaeological site were chosen to determine the area of consumption of pottery coffins produced at the Oryang-dong kiln. The samples from each area of remains were analyzed for minor elements using neutron activation analysis method, and from these results, the identities of the corresponding production areas were investigated using the multi-variant statistical analysis of discriminant analysis. The evidence strongly suggests that pottery coffins produced at the Oryang-dong kiln in Naju were used in ancient tombs of the Bannam mound in Naju, the Okyari mound in Yeongam, and the Banam mound in Hampyeong, reaching those sites through trade and distribution. The findings also suggest that pottery coffins from the Mandong archeological site in Gochang and the Inpyeong mound in Muan were not produced at the Oryang-dong kiln in Naju, but rather were brought from pottery kilns in different production areas, through trade and distribution.

• Journal of Microbiology and Biotechnology
• /
• v.20 no.12
• /
• pp.1630-1636
• /
• 2010

During the fermentation process of Saccharomyces cerevisiae, yeast cells must rapidly respond to a wide variety of external stresses in order to survive the constantly changing environment, including ethanol stress. The accumulation of ethanol can severely inhibit cell growth activity and productivity. Thus, the response to changing ethanol concentrations is one of the most important stress reactions in S. cerevisiae and worthy of thorough investigation. Therefore, this study examined the relationship between ethanol tolerance in S. cerevisiae and a unique protein called alcohol sensitive RING/PHD finger 1 protein (Asr1p). A real-time PCR showed that upon exposure to 8% ethanol, the expression of Asr1 was continuously enhanced, reaching a peak 2 h after stimulation. This result was confirmed by monitoring the fluorescence levels using a strain with a green fluorescent protein tagged to the C-terminal of Asr1p. The fluorescent microscopy also revealed a change in the subcellular localization before and after stimulation. Furthermore, the disruption of the Asr1 gene resulted in hypersensitivity on the medium containing ethanol, when compared with the wild-type strain. Thus, when taken together, the present results suggest that Asr1 is involved in the response to ethanol stress in the yeast S. cerevisiae.

• Korean Journal of Food Science and Technology
• /
• v.36 no.5
• /
• pp.711-716
• /
• 2004

Gamma irradiation was applied to dried pollack to improve its microbiological quality and evaluate quality stability of irradiated samples. Thermoluminescence (TL) properties of minerals separated from irradiated samples were measured for possible use in identifying irradiation treatment. Dried pollack was packaged in commercial unit (PVC film, 0.06 mm thickness) and stored at $15{\pm}1^{\circ}C$ for 6 months. Samples showed over $10^4\;CFU/g$ in total aerobic bacteria or yeasts&molds, which increased during storage, reaching $10^6-10^7\;CFU/g$ at 3rd month of storage. Irradiation at 3 kGy was effective for improving hygienic quality for 6 months, keeping microbial population under 20 CFU/g. Gamma irradiation at 3 kGy or less did not significantly influence physicochemical quality attributes, such as browning, TBA value, volatile basic nitrogen, trimethylamine, and sensory properties, whereas storage time remarkably induced quality changes of dried pollack. TL analysis was proved suitable for identifying irradiated from non-irradiated samples over 6 months of storage.