• Journal of Animal Science and Technology
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• v.49 no.4
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• pp.437-442
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• 2007

The melanocortin-4 receptor(MC4R) is virtually expressed in all brain regions and plays an important role in energy homeostasis in mammals. MC4R has been intensively studied as a trait gene controlling economically important traits, such as growth and feed conversion, etc. Six hundreds and sixty Duroc pigs were genotyped for the MC4R locus and analyzed their relationships with breeding values for average daily gain(ADG), backfat thickness(BF), days to 90kg(D90) and feed conversion(FC). The estimated genotype frequencies for the all Duroc pigs were: 30.8%, 45.2%, 24.1% for AA, AB and BB genotypes, respectively. The mutant A allele was significantly associated with ADG, D90 and BF whereas no significant relationship was found with FC. The change of gene frequencies by generation was shown in both selected and culled groups. These results indicate that the MC4R polymorphism could be integrated in the present selection program to realize a marker-assisted selection for the growth traits of the Duroc population.

• Journal of Animal Science and Technology
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• v.49 no.4
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• pp.443-450
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• 2007

This study was designed to investigate the seasonal variation in semen characteristics and the change of motility during semen frozen/thawed, and conception rates were observed following AI at the different times after estrus synchronization. Semen collected from March to May showed significantly lower semen quality than the other months (P<0.05) and semen characteristics (volume, total sperm and motility) were significantly higher in October. Sperm motility after thawing in frozen semen were significantly lower in non-breeding season than in breeding season (P<0.05). Conception rate after treatment of estrus synchronization and AI different time after CIDR device removal, at 60 hour was higher than those of any other times through AI but there was no significantly difference between AI times. Semen characteristics change gradually during the breeding and non-breeding season. These results were considered as a model for the use of assisted reproductive techniques for AI of deer in Korea.

• Journal of Animal Science and Technology
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• v.49 no.4
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• pp.451-458
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• 2007

This study was to investigate the effectiveness of pre-weaning injection of gonadotropin and scheduled fixed-time insemination on sow fertility. Sows were randomly assigned to receive gonadotropin 2 days before weaning, 1 day after weaning or none as control. In gonadotropin treated groups, half of sows were inseminated twice at 24 and 36 hours after onset estrus and half of sows were inseminated twice at scheduled fixed-time. Weaning to onset of estrus was the shortest in lactating sows injected with gonadotropin prior to weaning. Liter size was significantly higher in AI groups after detection of estrus, compared to fixed-time AI group. Results of these experiments indicated that injection of gonadotropin in lactating sows could initiate the final follicular development, and has potential to enhance the reintegration of estrus. Further researches are needed to define the relationship between reduced interval of wean to onset estrus and enhanced fertility in lactating sows.

• Journal of Korea Water Resources Association
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• v.51 no.1
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• pp.61-70
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• 2018

This study examined how to determine the optimal sediment level in dam reservoir for efficient plan and operation of dam. Currently, Korea is applying a horizontally accumulated method for sediment level estimation for the safety design of dam and so the method estimated relatively higher level than others. However, the sediment level of dam reservoir should be accurately estimated because it is an important factor in assessing life cycle of a dam. The sediment level in dam reservoir can be determined by SED-2D model linked with RMA-2, horizontally accumulated method, area increment method, and empirical area reduction method. The estimated sediment level from each method was compared with the observed sediment level measured in 2007 in Imha dam reservoir, Korea and then the optimal method was determined. Also, the future sediment level was predicted by each method for the future trend analysis of sediment level. As the results, the most accurate sediment level was estimated by the empirical area reduction method and the future trend of sediment level variation followed the past trend. Therefore, we have found that the empirical area reduction method is a proper one for more accurate estimation of sediment level and it can be validated by the results from a numerical model of SED-2D linked with RMA-2 model.

• Korean Journal of Microbiology
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• v.32 no.2
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• pp.147-154
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• 1994

Nuclease was secreted to the environmental media from the Escherichia coli JM107 tranformant harboring the extracellular nuclease gene of Serratia marcescens in the plasmid of pNUC4. Under the growth conditions, the amount of secreted enzyme was increased in parallel with bacterial growth conditions, the amount of secreted enzyme was increased in parallel with bacterial growth. The enzyme was purified using chromatofraphic procedures of Matrex green gel and heparin agarose affinity gel, resulted in 50-fold purification with 15% recovery of the enzyme. The apparent molecular weight of the enzyme was estimated to be 29Kda by sodium dodecylsulfate denaturing gel electrophoresis. Using the purified enzyme, polyclonal antibody was obtained from the rabbit. The specificity of the antibody was confirmed by immunoblotting and immunoprecipitaion. For the investigation of cellular distribution of the enzyme, cells were fractionated into three fractions; cytoplasm, periplasm and extracellular fluid. While more than 80% of the enzymatic activity was detected in the extracellular fluid and periplasm, a little was found in the cytoplasm, indicating that the enzyme was likely to be immediately exported to the membrane for excretion after biosynthesis. These results were confirmed again by immunocytochemistry technique using the antibody.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.3
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• pp.225-231
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• 2019

Purpose: This study was undertaken to compare fracture and flexural strength of provisional restorative resins fabricated by additive manufacturing, subtractive manufacturing, and conventional direct technique. Materials and methods: Five types of provisional restorative resin made with different methods were investigated: Stereolithography apparatus (SLA) 3D printer (S3Z), two digital light processing (DLP) 3D printer (D3Z, D3P), milling method (MIL), conventional method (CON). For fracture strength test, premolar shaped specimens were prepared by each method and stored in distilled water at $37^{\circ}C$ for 24 hours. Compressive load was measured using a universal testing machine (UTM). For flexural strength test, rectangular bar specimens ($25{\times}2{\times}2mm$) were prepared by each method according to ISO 10477 and flexural strength was measured by UTM. Results: Fracture strengths of the S3Z, D3Z, and D3P groups fabricated by additive manufacturing were not significantly different from those of MIL and CON groups (P>.05/10=.005). On the other hand, the flexural strengths of S3Z, D3P, and MIL groups were significantly higher than that of CON group (P<.05), but the flexural strength of D3Z group was significantly lower than that of CON group (P<.05). Conclusion: Within the limitation of our study, provisional restorative resins made from additive manufacturing showed clinically comparable fracture and flexural strength as those made by subtractive manufacturing and conventional method.

• Korean Journal of Veterinary Service
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• v.42 no.1
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• pp.25-30
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• 2019

The objective of this study was to assess the possibility of detecting Foot-and-Mouth Disease Virus (FMDV) from the herd-based oral fluids specimens collected by the cotton ropes from pig farms that were found as FMDV nonstructural protein (NSP) antibodies positive. The cotton ropes were applied to detect FMDV in the selected pig farms which NSP antibodies were continuously detected in 2016, including the one pig farm which FMDV antigen were detected at the specimens from the pigsty environment. As the result, FMDV antigen were not detected in the oral fluid specimens collected by the cotton ropes. Theoretically, to detect FMDV antigen from the pigs with NSP antibodies has very low possibility because FMDV antigen disappeared at the time when NSP antibodies were produced by FMDV. Therefore, in order to detect FMDV antigen from the oral fluids using the cotton rope, it would be more effective to be applied to target the FMDV infected pigs rather than the NSP antibodies positive pigs. The collected oral fluids using cotton rope could be useful test specimens to monitor high-density pig populations for FMDV infection. Then, oral fluids sampling using cotton rope will be used for the efficient FMDV surveillance to detect FMDV antigen.

• Journal of the Korean society of biological therapies in psychiatry
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• v.24 no.3
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• pp.184-193
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• 2018

Objectives : This study investigated the effects of social support and chronic medical conditions on depressive symptoms in elderly people living alone in a rural community. Methods : Sociodemographic information on 173 subjects aged 65 years or older who lived alone in a rural community and were recipients of National Basic Livelihood Security was collected and analyzed. All participants completed the Korean Form of the Geriatric Depression Scale and the Lubben Social Network Scale. Additionally, the current prevalence of chronic medical conditions that interfere with the activities of daily living was examined. Multiple logistic regression analysis was conducted to analyze the associations of social support and chronic medical conditions with depressive symptoms. Results : Social support(odds ratio: OR, 0.96; 95% confidence interval: 95% CI, 0.92-0.99) and chronic medical conditions(OR, 1.59; 95% CI, 1.23-2.05) were significantly associated with depressive symptoms in all subjects. When analyzed by gender, social support served as a protective factor against depressive symptoms in elderly men only(OR, 0.91; 95% CI, 0.83-0.99), and chronic medical conditions increased the risk of depressive symptoms in elderly women only(OR, 1.74; 95% CI, 1.26-2.40). Furthermore, osteoarthritis and lumbar pain were risk factors for depressive symptoms in all subjects(OR, 2.24; 95% CI, 1.10-4.56 and OR, 2.10; 95% CI, 1.08-4.12) and in elderly women(OR, 4.07; 95% CI, 1.68-9.84 and OR, 3.34; 95% CI, 1.47-7.57), respectively. Conclusion : This study indicates that improving the social support and managing the chronic medical conditions of elderly people living alone are important for the prevention of depression in this population. Additionally, the present results suggest that it is necessary to establish different depression-prevention strategies for elderly men and women living alone.

• The Journal of the Korea Contents Association
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• v.21 no.2
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• pp.78-84
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• 2021

Issues have arisen over the monopoly of housing sales guarantees by the Housing and Urban Guarantee Corporation. If the Ministry of Land, Infrastructure and Transport appoints an additional guarantee institution, there is concern that the property protection between the two parties is insufficient due to excessive competition and the weakening of urban regeneration resources. It argues that housing supply policies for stabilization of the housing market can be smoothly implemented through monopoly projects. This is judged to be an abuse of market dominant position under the Fair Trade Act, and excessive restrictions on pre-sale guarantee requirements may cause delays in business and infringement of property rights of members. First, the establishment of a designation system for market dominant operators of the Fair Trade Commission enables new entry of private guarantee institutions. Second, it is necessary to improve regulations under Article 63 of the Fair Trade Act (consultation on the establishment of laws restricting competition, etc.). Third, through the establishment of the 「Rules on Housing Supply」 under Article 15 (2), the Minister of Land, Infrastructure and Transport can additionally designate a guarantee institution, thereby guaranteeing the right to select a pre-sale guarantee for the business entity. In addition, it is expected that at least one of a number of guarantee insurance companies can be designated to improve the efficiency of the distribution of social benefits, thereby lowering the volatility of housing prices. Listen and suggest.

• Journal of Digital Convergence
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• v.19 no.3
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• pp.245-251
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• 2021

This study was to investigate the effect of the new surface treatment method of zirconia on the shear bond strength with resin cement. The zirconia specimens were classified according to the surface treatment. CON: non-treatment, HF: 10 minutes exposure to 9% HF, ZS15: Apply 15% ZrO2 slurry, ZS30: Apply 30% ZrO2 slurry, ZS50: Apply 50% ZrO2 slurry. The resin cement was layered on the surface treated zirconia, and the shear bond strength between the zirconia and the resin cement was measured after thermo-cycling. The statistical methods for shear bond strength were Kruskal-Wallis test, Mann-Whitney U test, and Bonferroni correction(α=.05/10=.005). ZS15, ZS30, and ZS50 groups treated with zirconia slurry showed higher shear bond strength than CON and HF groups(p<.05/10=.005). Within the limits of this study, the surface treatment using zirconia slurry increased the shear bond strength with resin cement. The new surface treatment method complements and improves the limitations of the adhesion of zirconia, so that various clinical applications of zirconia can be expected.