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        검색결과 409

        128.
        2018.11 구독 인증기관·개인회원 무료
        Sow longevity is important for efficient and profitable pig farming. Recently, there has been an increasing interest in social genetic effect (SGE) of pigs on stress-tolerance and behavior. The present study aimed to estimate genetic correlations among average daily gain (ADG), stayability (STAY), and number of piglets born alive at the first parity (NBA1) in Korean Yorkshire pigs, using the SGE model. The phenotypic records of ADG and reproductive traits of 33,120 and 11,654 pigs, respectively, were evaluated. The direct effect on ADG had a significantly negative genetic relationship with STAY, whereas the social effect on ADG had a neutral genetic relationship. In addition, the genetic correlation between the social effects on ADG and NBA1 tended to be positive, unlike the direct effects. The genetic correlation of the total effect on ADG with that of STAY was negative but non-significant, owing to the social effect. These results suggested that total genetic effect on growth in the SGE model might reduce the negative effect on sow longevity owing to the growth potential of pigs. We recommend including social effects as selection criteria in breeding programs to obtain satisfactory genetic changes in both growth and longevity.
        129.
        2018.11 구독 인증기관·개인회원 무료
        Cryopreservation of boar semen is continually researched in reproductive technologies and genetic resource banking in breed conservation. For evaluating the boar semen quality, sperm motility (MOT) is an important parameter because the movement of spermatozoa indicates active metabolism, membrane integrity and fertilizing capacity. Recently, polymorphisms reported to be significant association with sperm MOT. This study was conducted to evaluate the SNP in the coding region of ESR1 (g.672C>T inexon 1) as a positional controlling for motility and kinematic characteristics of post-thawed boar semen. To results,The g.672C>T was significantly associated with frozen semen motility and kinematic characteristics. g.158 T>C SNP was high significantly associated with MOT, VCL, VSL and VAP Also, the SNP was low significantly associated with ALH.Therefore, we suggest that theSNP in the coding region of ESR1 (g.672C>T in exon 1) may be used as a molecular marker for Duroc boar Post-thawed semen quality.
        130.
        2018.11 구독 인증기관·개인회원 무료
        Estrogen receptor 2 (ESR2) is involved in oestrogen-related apoptosis in cell cycle spermatogenesis but their effects have not yet confirmed in pig. Therefore, this study was performed to investigatetheir association with semen motility and kinematic characteristics. DNA samples from 126 Duroc pigs with records of sperm motility and kinematic characteristics [Total motile spermatozoa (MOT), Curvilinear velocity(VCL), Straight-line velocity(VSL), the ratio between VSL and VCL(LIN), Amplitude of Lateral Head displacement(ALH)] were used in present study. A single nucleotide polymorphism (g.35547A>G) was associated with MOT, VCL, VAP and ALH in Duroc population (p < 0.05). Therefore, we suggest that the porcine ESR2 may be used as a molecular marker for Duroc boar semen quality, although its functional effect was not clear yet. These results will improve the understanding of the functions of the ESR2 in spermatogenesis within the reproductive tracts, and will shed light on ESR2 as a candidate gene in the selection of good sperm quality boars.
        131.
        2018.11 구독 인증기관·개인회원 무료
        Acute kidney injury (AKI) is a disorder that is manifested by a sudden decrease of renal function within several hours, and AKI remains a significant cause that can lead to increasing morbidity and mortality. Although AKI has been extensively studies in animal models, translating the results from animal studies into clinical use has not been successful due to various factors including basal etiology of kidney deficiency and comorbidities and the complexity of this pathology. As a golden parameter, measuring serum creatinine (SCr) and blood urea nitrogen (BUN) has been conventionally used for determining the renal function, however, these biomarkers has been regarded suboptimal to identify renal injuries in early stages. In this study, we attempted to screen other serum biomarkers in early AKI event using cynomolgus monkeys. Two male monkeys, aged 60 months, were subjected to ischemic injury by unilateral clamping of renal pedicles for forty five minutes and then subsequently reperfused; the unclamped kidney was regarded as non-injured controls. Compared with control kidneys, we have found that the concentration of several inflammatory proteins including MCP1, TGFα, GSTα, were higher in the renal vein of injured kidney compared with control side after 24 and 48 hours of AKI. However, changes of serum level of KIM-1, which is one of the most-widely studied marker in rodent studies, were not different after AKI. Our results provide an useful information while developing a novel marker in AKI.
        134.
        2018.10 구독 인증기관·개인회원 무료
        The existing ethyl formate fumigant is carbon dioxide (CO2) mixed liquified gas in metal cylinder, but this product type costs a lot to manufacture, translate and maintain cylinder. To supplement these problems, we have developed a new ethyl formate fumigation technique with nitrogen (N2) carrier. We assessed the susceptibility of mealy bugs, the most frequently detected pests in imported banana, and phytotoxicity of banana fruits. Ethyl formate and nitrogen were concurrently treated on citrus mealybug, one of the most resistant mealybug to fumigant, and ethyl formate was treated with LC50 product of independent treatment dosage. Nitrogen was treated with 7 dosages from 79% to 95% concentration. Phytotoxicity of banana was assessed by treating EF 35 mg/L with N2 79% for 14 days, and color, sugar contents and loss of weight were measured. EF with N2 treatment showed more than 50% of mortality on every growth stages, and there was no significant difference between control and treatment banana fruits. These results indicate that concurrent treatment of EF and N2 can be used to control mealybug in banana fruits.
        136.
        2018.05 구독 인증기관·개인회원 무료
        Conventional airport concrete pavement design uses empirical design method presented by FAA but it is not accurate because it does not consider environment load. In case of mechanistic - empirical design method used overseas, it needs to be modified according to domestic conditions. In this paper, a stress regression model considering environmental load and dual tandem gear load is developed as a mechanical - empirical design process and verified by fatigue model calibration. First of all, literature review was conducted on airports using DT gear as a design aircraft among domestic airports, and the physical properties of concrete pavement layers of each airport were identified. In addition, the environmental load is divided into the temperature load and the moisture load, and the temperature load is calculated from the climatic data of the region where the domestic airport is located, and the moisture load is calculated through the drying shrinkage prediction model developed through the previous study. The stresses occurring in concrete slabs under environmental loads and traffic loads were predicted using FEAFAA, which is a finite element analysis program, and factors predicted to affect concrete pavement were selected for the stress regression.As a result of the sensitivity analysis of the selected factors, the joint spacing, slab thickness, gear load, and road bearing capacity coefficient affected the stress behavior of the slab by more than 5% of the reference stress.According to the mechanical design, the finite element analysis was carried out for the consideration of only the traffic load and the environmental load and the traffic load based on the design factors. Based on the analysis results, multiple regression analysis was performed using the statistical analysis program SPSS and the stress regression equation was calculated. Then, the stress model for the environmental load and the traffic load was calculated and the final stress model with each stress model as the independent variable was derived. Using the calculated stress regression model, the stress was calculated and the bending strength of the concrete was divided to calculate the stress - to - strength ratio, and the appropriate fatigue model was selected and the correction was performed by the least squares method. This study was supported by Incheon International Airport Corporation(BEX00625)
        137.
        2018.05 구독 인증기관·개인회원 무료
        Recently, in Seoul, Korea, GPR (Ground Penetration Rader)-based road cavities exploration technology was introduced for the exact cause analysis of road subsidence. The city of Seoul has identified a total of 2504 cavity in 2017 by using the introduced road cavities exploration technology, which shows that the incidence rate of road subsidence is reduced by 67%. However, GPR-based exploration technology is mainly concerned with cavities in the underground of the road pavement, and there is no effective method for areas with a danger zone depth of 1.5m or more and special areas such as narrow sidewalk. The EM (Electro Magnetic) method can be used to check the existence of cavities and poor ground in the underground using information on the location, shape, and electrical conductivity of the anomaly zone in the underground by measuring the electromagnetic field. Therefore, in this study, want to predict with a danger zone area by exploring the underground in the narrow sidewalk or park road by using the EM equipment which is capable of deep geological exploration, non - contact and equipment size change. In the previous research, the underground exploration was performed by simulating the ground and the cavities and the cavities including the metal. As a result, it was confirmed that an electrical resistivity anomaly zone occurred in the cavity regardless of the existence of the metal. Therefore, in order to analysis the applicability of the EM method in the underground cavities area according to the field simulation, this study will conduct the outside experiment by simulating actual sidewalk or asphalt pavement. In the future, the researchers will plan to examine the applicability of various factors such as type, condition and depth of road pavement.
        138.
        2018.05 구독 인증기관·개인회원 무료
        Airport concrete pavement slabs show contraction and expansion behavior due to environmental factors such as temperature and humidity. Among the various environmental factors, temperature is the most influential factor in the concrete slab. However, it is inadequate to consider air temperature or surface temperature as influential factors especially for airport concrete slabs with very large thicknesses. Therefore, this study intends to utilize the equivalent linear temperature difference calculated from the data of the thermometer embedded in 5 depths(50mm, 150mm, 250mm, 350mm, 450mm) on the airport concrete slab. Equivalent linear temperature difference is the temperature difference between the uppermost and lowermost part of the concrete slab, which shows the same behavior due to actual temperature. Since the upper part of the concrete slab is more affected by air temperature than the lower part, the daily temperature range is large. Therefore, the equivalent linear temperature difference increases during the day and decreases at night, and concrete slabs show curl-down during the day and curl-up at night. This daily variation of curling behavior causes a difference in HWD experimental results. The HWD(Heavy Weight Deflectometer) test is mainly performed to investigate the condition of the pavement. And the calculated values are deflection, ISM(Impact Stiffness Modulus), LTE(Load Transfer Efficiency). The equivalent linear temperature difference represents the behavior of the concrete slab by the environmental load, and the calculated values by the HWD test represent the behavior. Therefore, the purpose of this study is to investigate the behavior of concrete slab by combined load including environmental load and traffic load through correlation analysis between these values. This study was supported by Incheon International Airport Corporation(BEX00625) and Korea Airports Corporation.
        139.
        2018.05 구독 인증기관·개인회원 무료
        Airport concrete slabs behave by combined loads including environmental loads and traffic loads. To analyze the behavior of concrete slabs by combined load, the dynamic strain gages were embedded at 2 depths(50mm, 450mm) and 3 locations(corner, Center and Mid-Edge). And the thermometers were embedded at 5 depths(50mm, 150mm, 250mm, 350mm, 450mm) in actual airport concrete slabs. HWD(Heavy Weight Deflectometer) is a device to measure the deflection by applying an impact load. The values calculated by the HWD test are deflection, ISM(Impact Stiffness Modulus), LTE(Load Transfer Efficiency). Concrete slabs tend to expand during the summer when the temperature is high, and contract during the winter when the temperature is low. In addition, the drying shrinkage occurs as age increases. Field HWD test were conducted in March, May, August, and November to examine seasonal and age-specific changes. Furthermore, the temperature difference between top and bottom of concrete slabs causes the curl-up and curl-down behavior. The test was conducted 3 times at 12o`clock, 16o`clock, 21o`clock, 3o`clock, 7o`clock to examine temporal changes. The strain of the slab at HWD strike was measured 500 times per second because the strain occurred instantaneously, and the temperature was measure 1 times per 10 minutes. The calculated values and the measured values varied according to environmental loads. In order to examine these values in various angles, the equivalent linear temperature difference obtained by converting the temperature by depth into the uppermost lowermost temperature difference, the temperature of the slab which changes seasonally as a whole, and the drying shrinkage which occurs as the age increases are considered. Therefore, the purpose of this study is to clarify the behavior of concrete slabs by combined load considering long - term drying shrinkage, annual variation of temperature, and daily variations. This study was supported by Incheon International Airport Corporation(BEX00625) and Korea Airports Corporation.
        140.
        2018.05 구독 인증기관·개인회원 무료
        In this study, proposed how to design an airport concrete pavement expansion joint considering the weather conditions and material properties. Currently, expansion joint spacing of airport concrete pavement in korea is not designed according to a clear standard, but it is designed to an empirical level. Various types of Admixture are used in concrete pavement and depending on the material characteristics or local environmental factors, there is a substantial difference in the extent and shrinkage to which the package is inflated. Significant differences are made in the extent to which the pavement expands or shrinkage depending on the material characteristics used or the local environmental factors. But, expansion joint design performed on empirical criteria cannot reflect these materials and environmental characteristics, resulting in unpredictable damage such as blow-up. To analyzing behavior of airport concrete pavement, horizontal displacement gauges, static strain gauges and thermometers are installed in the 3rd phase construction sites at Incheon International Airport. In this study, the relationship between the temperature and horizontal displacement of the concrete pavement was analyzed using the measured depth temperatures and the horizontal displacement data at the expansion joints at the Incheon airport site. The Finite Element Analysis Model of Incheon International Airport pavement was used to compare the difference between actual behavior and analytical behavior. In addition, it is proposed to design a suitable expansion joint spacing by considering the maximum expansion of concrete pavement and shrinkage caused by material expansion (e.g., ASR) and shrinkage due to water loss. This study was supported by Incheon International Airport Corporation (BEX00625).