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        검색결과 10,008

        2941.
        2018.11 구독 인증기관·개인회원 무료
        To preserve the superior genetic resources and restore the endangered species, Somatic cell nuclear transfer (SCNT) has been used widely. In Korea, the research of dog cloning has made outstanding achievements including the production of the world`s first cloned dog. Sapsaree (Sapsalgae), the representative dog of Gyeongsan-si was designated as a Korea natural monument (No. 368). This male dog used in this study has azoospermia due to unknown cause. In this study, the aim was to confirm the cause of infertility in the cell donor dog and to evaluate the reproduction potential of dog cloning using infertile male dog by SCNT. First, to confirm the infertility of the cell donor dog, the reproductive history and the testis were evaluated. The breeding histology was not recorded in individual document. In histopathology, the Sertoli cell tumor was confirmed in biopsy of the cell donor dog after death. But, these tumors are predominantly in older dogs. Second, we produced the cloned dogs with the somatic cells of the infertile dog and the appearance was similar with the cell donor dog. Also, microsatellite analysis confirmed the genetic relationship between the cell donor and clone dogs. Third, the potential breeding capacity of the cloned dog was confirmed. In T4 assay, the normal dog (same age with cloned dogs), cell donor dog, and cloned dogs was investigated. The cell donor dog with azoospermia had very low T4 level, and cloned dogs showed higher level of T4 than normal dogs. In CASA, There was no significant difference in sperm motor ability between normal dogs and cloned dogs. As a result, cloned dogs produced by SCNT had no problem regarding the reproductive function of the testis. In AI experiment, the semen of clone dogs was used to fertilize a natural female bitch and was diagnosed pregnancy by ultrasonography. In total, 7 puppies were born by normal delivery (male: 3, female: 4). In conclusion, this study confirmed that the reproduction problem of non-genetic infertility can generate a normal descendant by SCNT. Also, the first successful research to restore infertile dogs was completed. Furthermore, SCNT would be useful for the restoration of endangered species and application of superior traits.
        2942.
        2018.11 구독 인증기관·개인회원 무료
        Although some factors, including season, age, type of estrus (natural estrus vs. induced estrus) and semen type (conventional vs. sexed), affect the conception rate following artificial insemination (AI) in dairy cattle, there is little information about the influence of ovarian characteristics, such as preovulatory follicle (PF) location at estrus, on fertility in dairy cattle. In most breeds of cattle the right ovary appears to function more actively than the left and about sixty percent of pregnancies in dairy cattle occur in the right horn of uterus (Reece and Tuner, 1938). Our study aimed to compare conception rates in dairy cattle between PFs that developed in the left ovary and those that developed in the right ovary at estrus. In this study, we examined the locational effect (left or right ovary) of the preovulatory follicle (PF) on fertility in dairy cattle. In total, 955 artificial inseminations (AI) were analyzed. At AI, PF locations were examined using rectal palpation, and dairy cattle were divided into two groups on their PF locations: (i) the PF located in the left ovary (L-PF); and (ii) the PF located in the right ovary (R-PF). Pregnancy was diagnosed by rectal palpation or ultrasonographic examination 60 days after AI. The conception rate was 38.1% in all dairy cattle. Conception rate was higher in the R-PF (40.8%) than in the L-PF (33.2%). In summary, PF development in the right ovary was associated with increased conception rates in dairy cattle.
        2943.
        2018.11 구독 인증기관·개인회원 무료
        Induced pluripotent stem cell (iPSC)-derived mesenchymal stem cells (iMSCs) serve as a unique source for cell therapy. We investigated whether exosomes from iMSCs promote the proliferation of human keratinocytes (HaCaT) and human dermal fibroblasts (HDFs). iPSCs were established from human Wharton’s jelly MSCs and were allowed to differentiate into iMSCs. Exosomes were collected from the culture supernatant of MSCs (MSC-exo) and iMSCs (iMSC-exo), and their characteristics were investigated. Both exosome types possessed basic characteristics of exosomes and were taken up by skin cells in vitro and in vivo. A significant increase in HaCaT proliferation was observed with iMSC-exo, although both exosomes increased the viability and cell cycle progression in HaCaT and HDFs. No significant difference was observed in the closure of wound scratch and the expression of reparative genes between cells treated with the two exosome types. Both exosomes enhanced the secretion of collagen in HaCaT and HDFs; however, an increase in fibronectin level was observed only in HaCaT, and this effect was better with iMSC-exo treatment. Only iMSC-exo increased the phosphorylation of extracellular signal-regulated kinase (ERK)-1/2. Our results indicate that iMSC-exo promote the proliferation of skin cells by stimulating ERK1/2 and highlight the application of iMSCs for producing exosomes.
        2944.
        2018.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study examined the color reproducibility and color fastness of digital textile printing for nylon sublimation transfer. After measuring the temperature and time suited to nylon sublimation transfer, the researchers conducted various tests for comparison and analysis including polyester transfer paper on polyester fabric to check dyeing characteristics, color change, sharpness, and the rubbing fastness of the dyeing samples for nylon sublimation transfer. These tests produced the following results. At 185℃ and 187℃, the sublimation transfer dyeing characteristics of nylon were similar to those of polyester and the researchers even observed superior color development in some colors; at a low temperature of 180℃, the sample that was worked on had the lowest level of color development. The examination of color difference (ΔE), which compared L*a*b* values, showed that the ΔE value of magenta was 10.34, that of yellow was 24.70, and that of black was 15.28. These results highlight the important role of heat treatment temperature and time on color development in nylon sublimation transfer. Concerning sharpness, the samples subjected to higher temperature heat treatment exhibited fewer color spreading phenomena around lines. Thus, dyeing properties and fastness can be enhanced by elongating time at low temperatures and shortening time at high temperatures; however, considering production time constraints as well as the need to produce industrially marketable quantities, the findings of this study suggest that the heat treatment temperature most suitable for nylon sublimation transfer is 187℃ for a duration of 50 seconds.
        4,000원
        2945.
        2018.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study analyzed and discussed the competition relation between various media platforms, particularly fashion magazine, the Internet portal, and social networking (SNS) that provide fashion contents. The following results were obtained through this study. First, the Internet portal ranks the highest in all factors, followed by SNS, and fashion magazine as the lowest. Second, the Internet portal was competing with fashion magazine and SNS because there is an overlap between the two platforms. By contrast, SNS has a relatively low degree of overlap with fashion magazines, and they are complementary to each other. Third, the Internet portal has a strong advantage over fashion magazine and SNS in all factors. On the basis of the results of this study, we can summarize remarkable points in strategy formulation as follows. First, the Internet portal, which is popularized by “usage accessibility,” is expected to continue to dominate the competition over other media platforms while providing greater gratification to users of fashion contents. Second, the competitiveness of fashion magazines, which has been shrinking dramatically, lies in the diversity and quality of fashion contents. Innovating ways to develop creative fashion content and improve the quality through more in-depth analysis of the reader is essential. Third, SNS is slightly behind the Internet portal as a whole; however, it is one of the emerging platforms in the fashion content market because of its competitive advantage in terms of gratification opportunities.
        5,700원
        2946.
        2018.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to promote the elderly apparel industry for the increasing numbers of elderly obese male population. In the study, a total number of 249 males between the ages of 60 to 85 were studied to analyze their body types and differences. The group had a Rohrer Index of 1.6 or higher and BMI of 25 or higher. The noticeable physical differences in the group were shorter waist front length, bigger waist and hip circumferences with increasing age and slimmer limbs that are associated with the natural aging process with or without obesity. The obese body types have been classified in the following 3 different categories. Type 1 is the group that has lower body obesity with broad shoulders and relatively slimmer abdomen than a heavy bottom. A total number of 84 people belonged to the type 1 obesity category which makes up 33.8% of the total. Type 2 is the group that has upper body obesity with especially large abdominal obesity. A total number of 76 people, 30.5% of the total, were classified as type 2. Type 3 is the group that has whole body obesity with balanced obesity in the whole body. A total number of 89 people, 35.7% of the total, made up type 3.
        4,600원
        2947.
        2018.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Visible and IR windows require a combination of high optical transparency and superior thermal and mechanical properties. Materials, fabrication and characterization of transparent ceramics for visible/IR windows are discussed in this review. The transparent polycrystalline Y2O3, Y2O3-MgO nanocomposites and MgAl2O4 spinel ceramics are fabricated by advanced ceramic processing and the use of special sintering technologies. Ceramic processing conditions for achieveing fully densified transparent ceramics are strongly dependent on the initial powder characteristics. In addition, appropriate use of sintering technologies, including vacuum sintering, hot-pressing and spark plasama sintering methods, results in outstanding thermal and mechanical properties as well as high optical transparency of the final products. Specifically, the elimination of light scattering factors, including residual pores, second phases and grain boundaries, is a key technique for improving the characteristics of the transparent ceramics. This paper discusses the current research issues related to synthesis methods and sintering processes for yttria-based transparent ceramics and MgAl2O4 spinel.
        4,500원
        2948.
        2018.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Microbubbles oxygen transfer to water was simulated based on experimental results obtained from the bubbles generation operated under varying liquid supply velocity to the multi-step orifices of the generator. It had been known that liquid supply velocity and bubble size are inversely related. In the oxygen transfer, a non-steady state was assumed and the pseudo stagnation caused the slow movement of bubbles from the bottom to the water surface. Two parameters were considered for the simulation: They represent a factor to correct the pseudo stagnation state and a scale which represented the amount of bubbles in supply versus time. The sum of absolute error determined by fitting regression to the experimental results was comparable to that of the American Society of Civil Engineers (ASCE) model, which is based on concentration differential as the driving force. Hence, considering the bubbles formation factors, the simulation process has the potential to be easily used for applications by introducing two parameters in the assumptions. Compared with the ASCE model, the simulation method reproduced the experimental results well by detailed conditions.
        4,000원
        2949.
        2018.10 구독 인증기관 무료, 개인회원 유료
        Rotor disc (로터 디스크)는 중대형 유조선에서 유류를 하역하는 장치인 COPT (Cargo Oil Pump Turbine)의 터빈을 고속으로 회전시키는 핵심 부품이다. 이 rotor disc는 중심 shaft에 여러 개의 turbine을 원주상으로 배열하고 체결하여 제작한다. 현재의 제작 방법으로는 turbine blade를 배열하고 shroud 덮개로 연결하여 riveting 방식으로 체결한다. 이런 고전적인 방법은 blade pitch의 불균일은 물론 작업 시 오류로 인해 blade에 손상이 가는 경우가 있다. 이러한 단점을 해결하기 위해서는 조립식의 rotor disc를 설계하여 제작방식을 변경해야 한다. 설계뿐만 아니라 조립식의 disc가 구조적으로 안정한지를 평가해야 한다. 본 논문은 blade의 설계와 이를 조립하였을 때에 구조안전성을 평가하기 위해 구조 해석하여 그 안전성을 검증 한다.
        3,000원
        2950.
        2018.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Epizootic HPAIV, H5N6, and H5N8 infections produced severe loss in poultry and wild birds in the Republic of Korea from 2016 to 2017. But pathological lesions and antigen distribution of the novel HPAIV H5N6 clade 2.3.4.4 in natural cases have been rarely reported. Herein, we describe the pathological lesions and antigen localization in chickens (layer and Korean native), ducks, and Japanese quail naturally infected by HPAIV H5N6. Grossly, severe reddening, swelling, and some necrotic foci, which were similar to septicemia or viremia, were observed in skin and many visceral organs including trachea, lung, liver, spleen, and pancreas. Histopathologically, pulmonary congestion and edema, as well as necrotizing hepatitis, splenitis, pancreatitis, myocarditis, and encephalitis were observed. Immunohistochemically, numerous HPAIV antigens were detected in necrotic parenchymal cells and in blood vessels of the respiratory, lymphoid, digestive, urinary, nervous, and cardiovascular systems. The results indicate that HPAIV H5N6 spread to the entire body via blood and caused severe damage throughout the entire body. The HPAI H5N6 clade 2.3.4.4 virus was isolated from samples of all four cases.
        4,000원
        2951.
        2018.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to examine the effect of new inoculants on in vitro digestibility and fermentation characteristics of high moisture rye silage. Rye was harvested at heading stage and divided into 5 treatments, following: No additives(CON); L. plantarum R48-27(NI1); L. buchneri R4-26(NI2); mixture of NI1 and NI2 at 1:1 ratio(MIX); and L. buchneri(LB). The rye forage was ensiled into 10 L bucket silo for 100 days. In vitro digestibility of dry matter and neutral detergent fiber were highest(p<0.05) in NI2 silage. The pH in NI2 and LB silages were lower(p<0.05) than CON silage. Lactate concentration was highest(p<0.05) in NI1 silage. While concentrations of acetate and propionate were highest(p<0.05) in MIX silage. Lactates : acetate ratio was highest(p<0.05) in NI1 silage, but lowest in LB silage. Butyrate concentrations of NI2 and LB silages were lower(p<0.05) than that in CON and NI1 silages. Lactic acid bacteria (LAB) count in all inoculated silages was higher(p<0.05) than that in CON silage, while yeast count in LB silage was lower than in CON, NI1, and MIX silages. In conclusion, application of NI2 inoculant could improve potentially fermentation quality and digestibility of high moisture rye silage.
        4,000원
        2954.
        2018.10 구독 인증기관·개인회원 무료
        This paper analyzed the disparity and causality between regional and industrial employment to invigorate balanced regional development of employment-side. This paper conducted of a Gini-coefficient decomposition method and Panel Granger causality test using the row-data of the Census on Establishments that were obtained from Statistics Korea. As a result of Gini-coefficient decomposition, although the growth rates of Gini-coefficient of employment are on the decrease, Gini-coefficient still increase in Korea. Most of employment disparity occurred from regional disparity between SMA (Seoul Metropolitan Area) and Non-SMA and from industrial disparity within the service industry. The amount of contribution to total disparity of inter/intra regional on employment were differed by industry. The causal relationship between an employment growths in the manufacture industry and an employment growths in the service industry were analyzed using a Panel Granger causality test. As a result, mutually causality were estimated in the analysis of national dimension. However, when limited region to the Non-SMA, only the employment growth in manufacture industry increases the employment growth in service industry. In order to reduce an employment disparity, strategies for resolving the regional disparity by industry are needed. For regional employment growths, strategies for the service industry in the SMA, and for the manufacture industry in the Non-SMA are needed.
        2955.
        2018.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objectives of this study were to determine in vitro dry matter and energy utilization of hatchery waste products and to confirm whether in vivo energy digestibility of hatchery waste products could be estimated using in vitro data. Two in vitro assays were conducted for infertile eggs, unhatched eggs, culled chicks, and a mixture(20% dried infertile eggs, 20% dried unhatched eggs, and 60% dried culled chicks). In Exp.1, in vitro dry matter disappearance (IVDMD) of hatchery waste products was determined. In Exp.2, in vitro energy disappearance (IVED) was determined using undigested residues from Exp.1. The IVDMD of infertile eggs, unhatched eggs, culled chicks, and the mixture were 81.7, 88.7, 83.9, and 85.4%, respectively. The IVED of the test ingredients were 74.4, 85.1, 77.6, and 79.8%, respectively. Both IVDMD and IVED were greater in unhatched eggs compared with infertile eggs and culled chicks (p<0.05). In vivo energy digestibility was estimated well using prediction equations for hatchery waste products developed in the present study: In vivo energy digestibility(%) = 2.52 × IVDMD (%) – 133.95 with r2 = 0.70 and in vivo energy digestibility(%) = 1.63 × IVED(%) – 50.03 with r2 = 0.67. In conclusion, energy utilization of unhatched eggs was the greatest among test ingredients and energy utilization of hatchery waste products can be estimated using data from in vitro procedures.
        4,000원
        2956.
        2018.10 구독 인증기관·개인회원 무료
        The first checklist of the Marsh Beetles (Coleoptera: Scirtidae) is presented based on literature records and specimens collected from Korean peninsula. The total of 19 species belonging to seven genera were catalogued. All recorded genus Cyphon species from Korean peninsula are transferred to genus Contacyphon by Zwick et al., 2013: Contacyphon coreanicus Klausnitzer, 1975, C. consobrinus Nyholm, 1949, C. laevipennis, C. padi (Linnaeus, 1758), C. palustris Thomson, 1855. Of these C. padi (Linnaeus), Hydrocyphon nakanei Yoshitomi, 2001, H. satoi Yoshitomi, 2001, Odeles inornata (Lewis, 1895), and Scirtes sobrinus Lewis, 1895 are recorded for the first time in South Korea. Photographs of dorsal adults and line drawings of diagnostic characters of new recorded Scirtids are provided. This work was supported by a grant from the National Institute of Biological Resources (NIBR), funded by the Ministry of Environment (MOE) of the Republic of Korea (NIBR201801201).