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        검색결과 71

        2.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, analyzed the cause of failure of the cardan shaft for water propulsion of an armored wheeled vehicle. During the development test(DT), the vehicle was deflected to the left on the water. As a result of the confirmation, increasing angular displacement and abrasion of SPIDER(Universal joint) occurred. As a result of a structure analysis and torsion fracture test, cause of failure is not insufficient design and strength deficit of each parts. and as a result of a simulation review of the assembly layout of each part, it was confirmed that excessive rotational vibration occurred. In order to solve this problem, improved the assembly layout of the water propulsion system and the worn SPIDER lubrication. Since there has been no occurrence of the same case between military operations so far, it has been confirmed that the improvement plan is appropriate.
        4,000원
        6.
        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.
        13.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 젖소의 분만계절에 비유곡선 모수를 추정하고, 추정된 비유곡선 모수를 이용하여 우리나라 젖소의 비유특성에 대한 기초자료를 제공하고자 실시하였다. 자료는 2009년부터 2011년까지 분만한 1산차 14,189두의 농협중앙회 검정자료를 이용하였으며, 비유곡선 모수는 Wood 모형을 적용하여, SAS 9.2 NLIN Procedure를 이용해 추정하였다. Wood 모형으로 추정 된 비유곡선 함수는 봄, 여름, 가을 및 겨울 분만에 대해 각각 yt=17.1726t0.2074e-0.00243t, yt=17.4108t0.1868e-0.00206t, yt=16.1367t0.2171e-0.00224t 및 yt=15.7759t0.2378e-0.00258t이었다. 봄, 여름, 가을 및 겨울의 분만에 대한 추정최고유량과 최고유량도달시기는 각각 32.55 kg, 84.70일, 31.53 kg, 90.99일, 32.21 kg, 96.51일 및 32.95 kg, 90.20일 이었다. 겨울의 분만이 여름의 분만보다 추정최고유량이 높았다. 또한 봄의 분만이 다른 계절보다 최고유량도달시기가 더 빨랐다.
        4,000원
        15.
        2011.10 구독 인증기관·개인회원 무료
        Cell transplantation therapy using adult stem cells has recently been identified as a potential treatment for spinal cord injury (SCI). But, recovery after traumatic SCI is very limited. As dogs are physiologically much more similar to human compared with other traditional mammalian models in disease presentation and clinical responses, a number of researches demonstrated canis familiaris is a suitable model for human diseases. This study investigated the effect of transplantation of canine Mesenchymal Stem Cells (cMSC) and neural-induced cMSC (nMSC) to understand how these cells improve neurological function in canine SCI model. The differentiation of cMSC into neural precursor cells was induced in dulbecco’s modified eagle’s medium supplemented with N2-supplement, dibutyryl cyclic adenosine monophosphate, and butylated hydroxyanisole. SCI was induced between T1 and T2 by surgical hemi-section in adult dogs, and then assigned to two groups according to the applied cell types (cMSC vs nMSC). Pelleted cMSC or nMSC were transplanted directly into the injured site after SCI, respectively. Analysis of motor function after transplantation was evaluated by modified Olby score. Magnetic resonance imaging (MRI), histological and immunohistichemical analysis were also performed. Functional recovery in group of cMSC was increasing gradually after transplantation and was higher than nMSC. In MRI, we could not confirm any difference between the cMSC and nMSC experimental groups. Immunohistochemically, beta3-tubuline and nestin were observed in injury site of two experimental groups with the expression level close to non-injured groups. Transplantation of mesenchymal stem cells could promote neuronal reconstruction and repair motor function in SCI. These showed mesenchymal stem cells could be a great candidate as a therapeutic tools in degeneration disease, and dogs could be used to explore human regenerative medicine as a promising animal model. This research was supported by iPET (Grants 110056032CG000), Ministry for Food, Agriculture, Forestry and Fisheries, Republic of Korea.
        16.
        2011.10 구독 인증기관·개인회원 무료
        Acteoside (verbascoside) is a typical phenylethanoid glycoside, extracted from various plants. It has various biological functions such as anti-oxidant, anti-inflammation, and anti-hypertension. Specially, it was powerful anti-oxidants either by direct scavenging of reactive oxygen and nitrogen species, or by acting as chain-breaking peroxyl radical scavengers. We examined the role of acteoside in IVM medium on the morphological progress of meiosis, developmental competence, and ROS in porcine oocytes. And we investigated effect of acteoside on the oocytes condition represented by cytoplasmic maturation by homogeneous distribution and formation of cytoplasmic organelles and regulation of apoptosis-related genes. The selected COCs were cultured in TCM-199 with various concentration of acteoside: 0 (control), 10, 30, and 50 μM. After 22 h of maturation with hormones, the oocytes were washed twice in a fresh maturation medium before being cultured in hormone-free medium for additional 22 h. The oocytes maturation rates of supplemented with acteoside were no significantly different compared with control group (71.13, 75.96, 72.95 and 73.68%, respectively). Level of ROS was significantly decreased in acteoside treated group. Furthermore, the parthenogenetic blastocyst rate was significantly improved in 10 μM acteoside treated group compared with control group (40.03 vs. 22.95%). During IVM, 10 μM acteoside treated oocytes showed that the mitochondria and lipid droplet were smaller and homogeneous distribution in cytoplasm compare with non-treated control oocytes. And reverse transcription polymerase chain reaction (RT-PCR) witarthenogenetic blstocysts revealed that acteoside increased the anti-apoptoticgenes, otherwise reibued pro-apoptotic genes. In conclusion, our results represents that addition of acteoside to the IVM medium has a beneficial effect in physiology of porcine oocytes such as viability and activation, providing a improved method for porcine oocytes in vitro.
        17.
        2010.11 구독 인증기관·개인회원 무료
        유류오염사고 해안방제시스템 구축을 위한 해안 구획분할을 연구하였다. 해 안 구획분할은 유류오염사고 발생시 오염피해평가, 방제 및 복원방법 선택, 방제전략 수립, 방제종료기준 선정 등을 위한 해안특성 정보 데이터베이스 구축을 위한 기본 단 위 구역 선정에 활용된다. 외국 사례의 검토를 통하여 체계적인 해안 구획분할 방안을 연구하고, 국내 적용을 위한 주요 검토사항을 제시하였다. 또한 해안 구획분할 적용에 있어 고려해야할 해안 특성요소를 검토하고 해안 특성요소를 반영할 수 있는 해안 구획 분할 방안을 제시하였으며, 분할된 해안 구획의 특성과 최적 방제방법을 연계할 수 있 는 방안을 연구하였다. 해안 구획분할 연구는 해안방제의 기초자료로 활용될 수 있으 며, 해안방제를 위한 정보시스템 구축에 기본 데이터베이스 단위로 적용될 수 있다.
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